Badger Meter vs Siemens Clarification Equipment: Comparison & Best Fit

Introduction

In wastewater treatment plant (WWTP) design, the clarifier is the hydraulic control center of the process, but its efficiency is entirely dependent on the accuracy of the feedback loops controlling it. A common challenge engineers face is the disconnect between mechanical clarification systems and the instrumentation required to optimize them. While mechanical failure is obvious, sensor drift or misapplication in Return Activated Sludge (RAS) lines or sludge blanket monitoring often goes unnoticed until a bulking event occurs, potentially costing utilities tens of thousands of dollars in violations and chemical correction. It is estimated that over 30% of clarifier performance issues are attributed not to the rake mechanism, but to improper process control data.

This brings us to the critical evaluation of Badger Meter vs Siemens Clarification Equipment: Comparison & Best Fit. It is important to clarify the scope immediately: while Siemens (often via legacy Envirex/Evoqua lines) manufactures mechanical clarifier structures, both Siemens and Badger Meter are titans in the process instrumentation that governs clarification. For the consulting engineer, the “equipment” choice is often a choice of sensing technology—flow meters, sludge blanket detectors, and solids analyzers—that integrate with the plant SCADA.

This article focuses on the engineering selection of this critical monitoring and control equipment. It analyzes how these manufacturers approach the harsh environment of primary and secondary clarification, where abrasion, grease coating, and low-flow velocities wreak havoc on standard specifications. By understanding the nuance in electrode materials, liner durability, and signal processing, engineers can specify systems that ensure the biological process remains stable.

How to Select / Specify

Selecting the right instrumentation for clarification loops requires a departure from standard clean-water specifications. The fluid dynamics of sludge, combined with the criticality of the RAS/WAS balance, demands a rigorous approach to the Badger Meter vs Siemens Clarification Equipment: Comparison & Best Fit analysis.

Duty Conditions & Operating Envelope

The operating envelope in clarification service is defined by solids concentration and velocity variability. Unlike potable water, clarifier influent and effluent lines handle fluid densities that fluctuate significantly.

• RAS Flow Measurement: The meter must handle solids concentrations typically ranging from 0.5% to 1.5% (5,000 to 15,000 mg/L). Engineers must verify that the magnetic flow meter’s signal-to-noise ratio is sufficient to distinguish flow velocity from the “noise” generated by particulate impact on electrodes.
• Velocity Turndown: Clarifiers experience diurnal flow patterns. Equipment must maintain accuracy (typically ±0.5%) at velocities as low as 1.0 ft/s during low-flow periods, while withstanding scour velocities up to 10-15 ft/s during storm events.
• Sludge Blanket Monitoring: Optical or ultrasonic sensors must penetrate the “fluff” layer to accurately identify the dense bed. The duty condition here is not pressure, but turbidity stratification. The sensor must be programmable to ignore transient clouds of solids.

Materials & Compatibility

Corrosion is rarely the primary failure mode in clarifier instrumentation; abrasion and coating are the true enemies.

• Liner Selection: For magnetic flow meters in RAS/WAS service, standard PTFE liners can sometimes delaminate under vacuum conditions or wear prematurely if grit removal is poor. Polyurethane or Neoprene liners are often preferred for their abrasion resistance, provided they are chemically compatible with any polymers added upstream.
• Electrode Material: In standard municipal wastewater, Stainless Steel 316L is the baseline. However, if the plant accepts industrial influent with high chloride content or corrosive chemicals, Hastelloy C-276 is the mandatory upgrade to prevent pitting.
• Sensor Housing: Sludge blanket detectors submerged in the clarifier must be constructed of non-corrosive PVC, CPVC, or Stainless Steel. Aluminum housings, even if coated, are generally unacceptable due to the corrosive nature of the headspace gases (H2S) and the liquid itself.

Hydraulics & Process Performance

The hydraulic profile of the clarifier piping gallery often challenges installation requirements. Accurate metering requires a stable velocity profile.

• Flow Disturbance: Magnetic flow meters typically require 5 pipe diameters (5D) upstream and 3D downstream of straight run. However, clarifier galleries are notoriously cramped, with elbows and check valves immediately adjacent to pumps.
• Tech Tip: If 5D/3D is impossible, engineers must evaluate equipment that offers “zero diameter” or reduced run requirements without significant accuracy degradation. Both Badger and Siemens offer solutions here, but the specific model’s coil geometry dictates performance.
• Head Loss: While generally negligible for full-bore mag meters, insertion-style meters or Venturi tubes (less common now) can introduce head loss that must be accounted for in the RAS pump hydraulic curve calculation.

Installation Environment & Constructability

The physical environment of a clarifier gallery or bridge is hostile to electronics.

• Ingress Protection: Equipment mounted on the clarifier bridge (sludge blanket sensors, drive monitors) must be rated NEMA 4X (IP65/66) at minimum. For sensors inside the tank or in flood-prone galleries, IP68 (continuous submersion) is the only safe specification.
• Cable Runs: Signal cables for bridge-mounted sensors must route through slip rings in circular clarifiers. The specification must account for signal integrity (shielding) passing through these rotating contacts.
• Separation: High-voltage power cables for the rake drive motor can induce noise in low-voltage 4-20mA sensor cables. Proper conduit separation is non-negotiable.

Reliability, Redundancy & Failure Modes

In the context of Badger Meter vs Siemens Clarification Equipment: Comparison & Best Fit, reliability is measured by maintenance intervals.

• Coating Detection: Grease and biological slime will coat electrodes over time, insulating them and causing signal drift. Advanced flow meters feature “electrode cleaning” circuitry (high frequency or capacitive checks) or diagnostic alarms that notify SCADA when impedance rises, indicating a coating issue.
• MTBF: The electronics (transmitter) are usually the weak link, not the flow tube. Look for modular designs where the transmitter can be replaced without removing the flow tube from the line—a critical constructability and maintenance feature.

PRO TIP: When specifying flow meters for RAS lines, mandate “Empty Pipe Detection.” If a RAS pump fails or loses prime, the meter should not read a false positive or erratic value. It must lock to zero to prevent the control system from ramping up other pumps erroneously.

Controls & Automation Interfaces

Integration capability separates modern hardware from legacy equipment.

• Protocols: While 4-20mA is standard, modern design favors digital bus integration. Siemens equipment typically excels in Profibus/Profinet environments (common in Siemens PLC architectures), while Badger Meter devices are highly flexible with EtherNet/IP, Modbus TCP/IP, and BACnet.
• Diagnostics availability: The engineer should specify that diagnostic data (coil temp, electrode impedance, signal strength) be available over the digital bus, not just the process variable (flow rate). This enables predictive maintenance.

Lifecycle Cost Drivers

The purchase price of a 12-inch mag meter is a fraction of its 20-year cost.

• Calibration Verification: Pulling a 12-inch meter for calibration is expensive and disruptive. Specify meters that support in-situ verification tools (electronic simulators) that validate the transmitter and sensor health without removal.
• Power Consumption: In large plants with hundreds of instruments, the power draw of field devices adds up, though it is secondary to the pumping cost.
• Consumables: For sludge blanket sensors, consider if they use wipers (mechanical wear parts) or air cleaning (compressor O&M required).

Comparison Tables

The following tables provide a direct technical comparison to assist in the Badger Meter vs Siemens Clarification Equipment: Comparison & Best Fit decision process. Table 1 focuses on the primary product lines utilized in clarification service, while Table 2 outlines the application suitability based on process constraints.

Table 1: Manufacturer & Technology Profile (Clarification Instrumentation)

Manufacturer / Product Line	Primary Technology	Key Features	Limitations / Considerations	Maintenance Profile
Badger Meter ModMAG M2000 / M5000	Electromagnetic Flow	Broad liner options; M5000 is battery-powered (good for remote vaults); Class 1 Div 2 ratings available. High accuracy (±0.25%).	Battery versions have lower sample rates (less responsive to rapid flow changes).	Low. Electrode cleaning required in greasy service. Verification tool available.
Siemens SITRANS F M (MAG 5100/6000)	Electromagnetic Flow	SENSORPROM memory unit stores calibration (plug-and-play transmitter swap); Composite liners available; Deep integration with Siemens TIA Portal.	Proprietary memory chip dependency; Profibus bias in older specs (though Modbus available).	Low. SENSORPROM simplifies electronics replacement significantly.
Badger Meter (ATi/s::can) Optical / Acoustic Analyzers	Sludge Blanket / TSS	Advanced spectral analysis for solids; Self-cleaning capabilities; Multi-parameter probes (TSS + Turbidity).	Optical windows require consistent cleaning (wipers/air); Sensitivity to color changes in industrial waste.	Medium. Consumable wipers/seals. Periodic validation against lab samples.
Siemens Echomax / SITRANS Probe LU	Ultrasonic Level	Sonic Intelligence echo processing filters out rake arm interference; “Auto False-Echo Suppression”.	Foam on surface can absorb signal; “Fluff” layers can sometimes be misread as hard blankets without proper tuning.	Low. Non-contact. Requires periodic cleaning of transducer face if splashing occurs.

Table 2: Application Fit Matrix

Application Scenario	Badger Meter Best Fit	Siemens Best Fit	Key Engineering Constraint	Selection Verdict
RAS Pumping (High Vibration/Solids)	ModMAG with Polyurethane Liner	MAG 5100 W with Hard Rubber	Abrasion resistance and vibration immunity.	Tie. Decision often drives by existing SCADA standard (EtherNet/IP vs Profibus).
Clarifier Blanket Level	Smart Sensors (s::can)	Echomax Transducers	Distinguishing “fluff” from settled sludge.	Siemens for simple top-down level; Badger for analytical profiling.
Remote/Vault Metering (No Power)	ModMAG M5000 (Battery)	MAG 8000 (Battery)	Power availability vs. Data transmission frequency.	Badger M5000 is widely favored for robust battery life and ease of access.
Plant-Wide Automation Upgrade	Flexible Protocols	TIA Portal Integration	Ease of integration config.	Siemens wins if the plant uses Siemens PLCs; otherwise neutral.

Engineer & Operator Field Notes

Theory often diverges from practice in the field. The following notes cover real-world experiences with commissioning and maintaining clarification instrumentation.

Commissioning & Acceptance Testing

The Site Acceptance Test (SAT) is where the specification is validated. For clarification equipment, the most critical step is the “Zero Verification.”

• The Zeroing Challenge: To properly zero a mag meter, the pipe must be full of liquid but with absolutely zero velocity. In a RAS gallery, achieving this is difficult because isolation valves often leak slightly. Engineers should specify double block-and-bleed valves or ensure downstream check valves are tight before attempting to zero. Attempting to zero a meter with even 0.1 ft/s of flow will offset the calibration across the entire range.
• Signal Damping: During startup, RAS flow can be turbulent. Operators often crank up the “damping” or “smoothing” parameter in the transmitter to stabilize the reading. However, over-damping (e.g., >30 seconds) makes the control loop sluggish. A best practice is to keep damping under 10 seconds and address the hydraulic noise source if possible.

Common Specification Mistakes

One of the most frequent errors in Badger Meter vs Siemens Clarification Equipment specifications involves the ground reference.

• Grounding Rings: In plastic piping (PVC/HDPE) often found in smaller chemical feed or sampling lines, there is no earth ground for the fluid. Without grounding rings (or a grounding electrode built into the sensor), the meter will read stray electrical noise as flow. Both manufacturers offer built-in grounding electrodes—specify them to save installation labor.
• Remote Electronics Cable Length: Specifying remote transmitters (mounted on the wall away from the pipe) is good for ergonomics, but there is a hard limit on cable length (typically 100-300ft depending on conductivity). Exceeding this without a signal booster results in signal degradation.

COMMON MISTAKE: Specifying standard ultrasonic level sensors for sludge blankets without accounting for the rake arm. As the rake passes under the sensor, it creates a massive echo. Modern controllers (like Siemens Hydroranger) have algorithms to ignore this repeating target, but they must be mapped during commissioning. Failure to map the rake results in a “High Level” alarm every time the arm passes.

O&M Burden & Strategy

Maintenance teams prefer equipment that tells them when it’s sick.

• Predictive Maintenance: Use the verification tools (e.g., Siemens Verificator or Badger Meter Verification) annually. This generates a pass/fail report for regulatory compliance without removing the meter.
• Sludge Blanket Sensor Cleaning: Optical sensors in the clarifier require frequent cleaning. If the plant does not have an automatic air-blast system specified, operators must manually wipe the lenses weekly. This is a high-labor activity that is often neglected, leading to useless data. Always specify the auto-clean option.

Design Details / Calculations

Proper integration of clarification equipment requires adherence to specific sizing logic and standards.

Sizing Logic & Methodology

Do not simply match the meter size to the pipe size. This is “line-size” specifying and is often incorrect for metering.

1. Determine Flow Range: Identify Minimum Day (low flow) and Peak Hour (storm) RAS rates.
2. Calculate Velocity: $V = Q / A$.
   • $Q$ = Flow (cfs)
   • $A$ = Area (sq ft)
3. Check Constraints:
   • Minimum velocity > 2.0 ft/s (to prevent solids deposition in the meter tube).
   • Maximum velocity < 20 ft/s (to prevent liner wear).
   • Ideal operation is 4-10 ft/s.
4. Reduce if Necessary: If the 12-inch pipe yields only 1.0 ft/s at average flow, it is engineering best practice to reduce the meter section to 8-inch or 10-inch to increase velocity and accuracy, provided the head loss is acceptable.

Specification Checklist

When writing the CSI Division 40 specification (Process Integration), ensure the following are explicitly defined:

• Flange Compatibility: ANSI Class 150 is standard, but check if mating to DIN standard equipment on imported clarifiers.
• Power Supply: 24VDC is safer and standard for instrumentation, but 120VAC is common in older plants. Ensure the spec matches the panel design.
• Coating: Epoxy coating on the exterior of the flow tube to resist the damp, corrosive gallery environment.
• Tagging: Stainless steel tag wired to the device with the exact SCADA tag ID (e.g., 20-FIT-101).

Standards & Compliance

• AWWA C700 Series: While primarily for cold water meters, principles of accuracy apply.
• NSF-61: Required if the clarifier effluent is potentially reused or enters a potable source (less common for wastewater, but relevant for water treatment clarifiers).
• NEC (NFPA 70): Hazardous location classification. Clarifier galleries are often Class 1 Div 2 (due to methane possibility if ventilation fails) or unclassified. If enclosed and poorly ventilated, explosion-proof (Ex d) or Intrinsically Safe (IS) barriers may be required for the instrumentation.

Frequently Asked Questions

What is the primary difference between Badger Meter and Siemens for clarification applications?

The primary difference lies in their core focus and integration. Siemens (often under the Milltronics or Sitrans brand) offers a portfolio deeply integrated with their automation and drives (PLC/VFD) ecosystem, making them a strong choice for plants utilizing Siemens control architectures. Badger Meter focuses heavily on independent, high-precision measurement and has recently expanded into water quality analytics (ATi/s::can). For pure flow measurement, they are functionally equivalent; for holistic clarifier control (drives + sensors), Siemens provides a single-source advantage.

How do you select the correct liner for a RAS flow meter?

Liner selection is driven by abrasion and chemical resistance. For Return Activated Sludge (RAS), Polyurethane or Neoprene are typically best because they resist the abrasion of grit and sand often found in primary sludge better than PTFE (Teflon). PTFE is slick but can be soft and prone to delamination under vacuum pressure if a pipe drains. Hard Rubber is a durable, cost-effective legacy standard that also performs well in general wastewater.

Why do ultrasonic sludge blanket detectors fail in secondary clarifiers?

Ultrasonic detectors often fail due to the “fluff layer” problem. Secondary clarifiers often have a low-density cloud of solids floating above the dense blanket. Basic ultrasonic sensors may bounce the signal off this fluff, reporting a high blanket level when the actual bed is low. Advanced sensors allow the engineer to adjust the “sensitivity” or “gain” to penetrate the light fluff and detect the denser interface below. Optical sensors (turbidity based) are generally more accurate for profiling but require physical contact and cleaning.

How often should mag meters in clarification service be calibrated?

True wet calibration requires removing the meter and placing it on a flow rig, which is rarely done after installation. Instead, electronic verification should be performed annually. This involves using a manufacturer-specific tool (like the Siemens Verificator or Badger Meter Verify device) to check the magnetism of the coils and the integrity of the transmitter electronics. If the verification passes, the meter is considered within calibration tolerance for process control purposes.

Can I use insertion flow meters for clarifier piping?

Insertion mag meters are an option for very large pipes (>24 inches) where a full-bore meter is cost-prohibitive. However, they are generally not recommended for RAS/WAS lines. Insertion probes are prone to fouling (ragging) where the sensor enters the flow stream. They also rely on a developed flow profile which is rare in clarifier galleries. Full-bore electromagnetic meters are the industry standard for reliability and low maintenance.

Conclusion

Key Takeaways for Engineers

• Define Scope: “Equipment” selection is a choice of instrumentation (Process Control) vs. Mechanics. This article focused on the critical sensors that drive the process.
• Velocity Matters: Do not line-size flow meters. Size for a velocity range of 2-10 ft/s to ensure accuracy and self-cleaning.
• Abrasion Resistance: Specify Polyurethane or Neoprene liners for RAS/WAS applications to extend lifecycle.
• Integration Strategy: Choose Siemens if deep integration with TIA Portal/Siemens PLCs is a priority. Choose Badger Meter for highly flexible, protocol-agnostic, and specialized analytical applications.
• Maintenance Access: Ensure zero-flow conditions can be achieved for calibration, and specify auto-cleaning for any optical sensors.

In the evaluation of Badger Meter vs Siemens Clarification Equipment: Comparison & Best Fit, there is no single “winner,” but there are distinct “best fits” based on plant architecture. For facilities heavily invested in the Siemens automation ecosystem, the synergy between SITRANS instrumentation and SIMATIC controls offers a streamlined, single-source lifecycle advantage.

Conversely, for engineers designing open-architecture systems or retrofitting existing plants where instrument-level flexibility is paramount, Badger Meter’s ModMAG and s::can lines offer robust, high-performance solutions that stand independently of the PLC brand. The consulting engineer’s role is to look beyond the brand name and specify the physics—materials, hydraulics, and signal processing—that will survive the hostile environment of the clarifier gallery.

source https://www.waterandwastewater.com/badger-meter-vs-siemens-clarification-equipment-comparison-best-fit/

Krohne vs ABB Clarification Equipment: Comparison & Best Fit

Introduction

The secondary clarifier is often described as the most critical bottleneck in activated sludge systems, yet its performance is frequently limited by the quality of the data feeding the control loops. For municipal consulting engineers and plant directors, the “black box” nature of clarification—where settling zones and compression layers are hidden beneath the surface—presents a persistent operational challenge. A surprising industry statistic suggests that up to 40% of unintentional solids carryover events are caused not by hydraulic overload, but by instrument failure or lack of visibility into sludge blanket dynamics, leading to delayed Return Activated Sludge (RAS) adjustments.

When engineers evaluate the market for reliable process monitoring, the conversation often centers on Krohne vs ABB Clarification Equipment: Comparison & Best Fit. It is important to clarify a fundamental distinction immediately: neither Krohne nor ABB typically manufactures the heavy mechanical clarification equipment (such as scraper mechanisms, drive cages, or suction headers). Rather, they manufacture the critical instrumentation and control equipment that serves as the nervous system for the clarifier. Without precise electromagnetic flowmeters for RAS/WAS lines, accurate turbidity sensors for effluent compliance, and reliable sludge blanket level detectors, the mechanical equipment cannot operate efficiently.

This technology is utilized across municipal wastewater treatment plants (WWTPs) and industrial effluent treatment systems (ETPs). From primary sedimentation to final clarification and gravity thickening, the instrumentation must survive harsh, corrosive, and bio-fouling environments. The consequences of poor specification in this area are severe: abrasive sludge can destroy standard flowmeter liners in months, and optical sensors without adequate cleaning systems can drift within hours, rendering automation useless.

This article provides a rigorous technical analysis to help engineers accomplish a specific goal: specifying the correct instrumentation package for clarification systems. We will move beyond brochure specifications to analyze the real-world performance, maintenance burdens, and application suitability of the Krohne and ABB portfolios.

How to Select / Specify Clarification Instrumentation

Selecting the right sensor suite requires a deep understanding of the process dynamics within a clarifier. Engineers must evaluate the equipment based on the specific constraints of sludge handling and optical measurement.

Duty Conditions & Operating Envelope

The operating envelope for clarification instrumentation varies significantly between primary and secondary stages. For flow metering (RAS/WAS), the solids concentration is the primary variable. Primary sludge can range from 3% to 6% solids, often containing grit and rags that pose abrasion and clogging risks. Secondary sludge (RAS) is typically 0.5% to 1.5% solids but is biologically active, leading to rapid biofilm formation on sensor surfaces.

When evaluating Krohne vs ABB Clarification Equipment: Comparison & Best Fit regarding duty conditions, engineers must verify the liner material and electrode design of magnetic flowmeters. For sludge blanket level monitoring, the “operating envelope” refers to the distinct stratification layers. The sensor must distinguish between the fluffy “rag layer” (hindered settling zone) and the compacted sludge bed. Devices that rely solely on a single ultrasonic echo often fail in bulking sludge conditions, whereas optical profilers can detect density gradients.

Materials & Compatibility

Corrosion and abrasion are the twin enemies of clarifier instrumentation.

• Flowmeter Liners: For abrasive primary sludge or grit removal lines, soft rubber or polyurethane liners are often specified for their resilience. However, in chemically aggressive industrial clarification (e.g., metal finishing or pulp and paper), PTFE or PFA liners are required.
• Electrodes: Standard 316L Stainless Steel is generally sufficient for municipal wastewater. However, if ferric chloride or alum is dosed upstream for phosphorus removal, the chloride content can cause pitting. In these cases, Hastelloy C or Titanium electrodes should be specified.
• Submerged Components: Sludge blanket sensors operate underwater continuously. Housings should be 316L SS or high-grade PVDF. Cable jackets must be resistant to UV radiation (where exposed on the bridge) and hydrolysis (where submerged).

Hydraulics & Process Performance

Hydraulic conditions significantly impact sensor performance. Magnetic flowmeters generally require 5 diameters (5D) of straight pipe upstream and 2D downstream to ensure a symmetric flow profile. In retrofits, where RAS galleries are cramped, this is often impossible. Here, the selection turns to technology capable of handling flow disturbances.

For suspended solids and turbidity sensors, hydraulic velocity is critical. If the sample flow is too low across the sensor face, solids will settle and foul the lens. If too high, it may shear flocs or cause cavitation bubbles that scatter light, creating false high readings. Specifications must define the installation angle (typically 45 degrees downstream) to utilize self-cleaning hydraulic forces.

Installation Environment & Constructability

The physical installation environment on a clarifier bridge presents unique challenges.

• Rotating Bridges: For circular clarifiers with rotating bridges, power and signal transmission must pass through a slip ring assembly. Engineers must specify 2-wire (loop-powered) devices where possible to minimize the number of slip ring channels required. Wireless signal transmission is becoming a viable alternative to noisy slip rings.
• Mounting Locations: Sludge blanket sensors must be mounted away from the feed well (turbulence) and the scum beach. The optimal location is typically 1/3 to 1/2 of the radius in from the outer wall, where the blanket is most stable.
• Sun and Temperature: Transmitters mounted on the bridge are exposed to direct sunlight. UV shields or sunshades are mandatory specification items to prevent LCD screen blackening and internal electronics overheating.

Reliability, Redundancy & Failure Modes

In the context of Krohne vs ABB Clarification Equipment: Comparison & Best Fit, reliability is defined by the Mean Time Between Maintenance (MTBM). The most common failure mode for analytical sensors is fouling. An optical sensor without a wiper or air-blast cleaning system will fail within 24-48 hours in wastewater.

Redundancy strategies often involve “voting logic.” For critical RAS flow, plants may rely on a magmeter as the primary instrument, with a V-notch weir measurement or pump speed curve calculation as a backup validation variable in the SCADA system.

Controls & Automation Interfaces

Integration with the plant SCADA is paramount.

• Protocols: While 4-20mA HART is the industry standard, modern specifications increasingly call for EtherNet/IP or Profibus for deeper diagnostics. This allows the instrument to report not just the process variable (e.g., Flow), but also its health status (e.g., “Electrode Coating Detected”).
• Control Strategies: Sludge blanket level data is used to control the RAS pump speed. If the blanket rises, the RAS rate increases. This loop requires a damped signal; raw data is often too noisy. The instrument transmitter should have adjustable damping settings (0-100 seconds).

Maintainability, Safety & Access

Clarifier bridges can be slippery and dangerous in winter. Operators should not have to lean over handrails to clean sensors.

• Retraction Assemblies: Specify rail-mounting kits with pivot arms or chain-hoist retrievers that allow the operator to pull the sensor onto the walkway for cleaning without breaking the plane of the handrail.
• Remote Electronics: Whenever possible, specify remote-mounted transmitters located at the end of the bridge or in a gallery, rather than compact versions mounted on the sensor itself. This keeps the operator interface accessible.

Lifecycle Cost Drivers

The Total Cost of Ownership (TCO) analysis typically favors higher-spec instruments in clarification.

• CAPEX: A motorized optical sludge profiler costs significantly more ($8k-$12k) than a simple ultrasonic gap switch ($2k-$4k).
• OPEX: The ultrasonic switch requires manual calibration and frequently gives false readings during upset conditions, requiring operator intervention. The motorized profiler provides a true depth profile and self-cleans. The labor savings over 10 years often justify the higher CAPEX.
• Consumables: Consider the cost of wiper blades, reagents (if applicable for other analytes), and backup batteries for wireless units.

Comparison Tables: Krohne vs ABB

The following tables provide a direct comparison of the instrumentation portfolios relevant to clarification. Table 1 focuses on the specific technology strengths of each manufacturer, while Table 2 assists engineers in selecting the best fit based on application constraints.

Table 1: Manufacturer Technology Profile (Clarification Scope)

Comparison of Key Instrumentation Lines for Clarifiers

Manufacturer	Core Product Lines	Primary Strengths	Best-Fit Applications	Limitations / Considerations
Krohne	OPTISYS SLM 2100 (Optical Sludge Blanket) OPTIFLUX 2000/4000 (Magmeters) OPTISENS (Turbidity/TSS)	Optical Profiling: The SLM 2100 is a market leader for physically tracking the sludge interface using a motorized optical sensor. Diagnostics: Excellent conductivity diagnostics in magmeters to detect gas bubbles or coating.	Secondary Clarifier Blanket Level (precise interface tracking). WAS Flow (high solids handling). Thickener Bed Level.	The motorized cable system requires mechanical maintenance (pulleys/cable) compared to non-contact sonic sensors.
ABB	WaterMaster / ProcessMaster (Magmeters) Aztec Series (ATS430) (Turbidity/TSS) LST Series (Ultrasonic Level)	Self-Verification: VeriMaster software allows in-situ verification of flowmeter calibration without removal. Sensor Design: ATS430 turbidity sensor features a highly effective wiper system and robust optical design.	RAS/WAS Flow Metering (especially remote locations). Effluent Turbidity Compliance. Remote data access situations.	Historically less focused on motorized sludge blanket profiling compared to Krohne; relies more on ultrasonic/sonic echo technologies or partner solutions for interface level.

Table 2: Application Fit Matrix

Decision Matrix for Selecting Krohne vs ABB Solutions

Application Scenario	Critical Constraint	Krohne Best Fit	ABB Best Fit	Engineering Verdict
RAS Flow Measurement	Pipe Vibration & Grease Coating	OPTIFLUX 4300 Capacitive coupled options available for extreme coating.	WaterMaster Octagonal bore reduces sensitivity to profile disturbance; advanced signal filtering.	Tie. ABB WaterMaster is often preferred for ease of verification; Krohne excels if media is extremely noisy.
Sludge Blanket Level	Fluffy/Bulking Sludge (Poor SVI)	OPTISYS SLM 2100 Directly measures suspended solids concentration at depth.	Ultrasonic/Sonar May struggle to distinguish rag layer from blanket.	Krohne Wins. For difficult settling sludge, the direct immersion optical profiler provides superior data to sonar.
Effluent Turbidity	Low Detection Limit (Regulatory)	OPTISENS TUR 2000 Standard 90-degree scatter method.	Aztec ATS430 Advanced optical design with minimal drift.	ABB Wins. The Aztec series has a strong legacy in municipal compliance monitoring with robust wiper mechanisms.
Installation Constraints	Buried Sensor / Flooded Vaults	IP68 Ratings Robust potting options available.	Potting & Remote Cables Sensors designed for indefinite submersion.	Tie. Both manufacturers offer excellent IP68/NEMA 6P options for magmeters.

Engineer & Operator Field Notes

The difference between a successful installation and a maintenance nightmare often lies in the details of commissioning and daily operation. The following notes are compiled from field experiences with Krohne vs ABB Clarification Equipment: Comparison & Best Fit implementations.

Commissioning & Acceptance Testing

Commissioning clarification instrumentation requires more than just powering up the device.

• Zero-Point Calibration (Magmeters): Never assume the factory zero is perfect for your installation. Fill the RAS pipe, ensure the liquid is static (zero flow), and perform a zero calibration in the field. This accounts for local electrical noise and grounding conditions.
• Blanket Profiling Setup: For the Krohne OPTISYS or similar profiling units, you must define the “bottom” and the “surface.” Commissioning must include a “teach” cycle where the probe lowers to the floor (or a preset stop) to map the tank depth. You must also configure the sensitivity threshold—at what TSS concentration does the instrument decide it has hit the “blanket”? A common error is setting this too low, causing the sensor to report the fluff layer as the blanket.
• Interference Mapping: If using ultrasonic/sonar technologies (common in some ABB configurations), you must map out false echoes caused by skimmer arms, launder troughs, or internal piping.

PRO TIP: When commissioning optical sludge blanket sensors, lower a manual “Sludge Judge” (clear plastic core sampler) alongside the automatic sensor. Compare the visual interface in the tube with the digital reading. Adjust the sensor’s concentration threshold until it matches the visual “top of blanket” observed in the Sludge Judge.

Common Specification Mistakes

One of the most frequent errors in clarifying specifications is over-specification of accuracy and under-specification of cleaning.

• Accuracy vs. Repeatability: In sludge blanket monitoring, ±1 cm accuracy is irrelevant if the blanket is undulating by ±10 cm. Repeatability is more important. Do not pay for lab-grade accuracy where process noise dominates.
• Missing Flush Ports: Specifying flowmeters on sludge lines without flushing rings or ports is a critical mistake. When (not if) the line plugs or needs maintenance, operators need a way to inject high-pressure water or air to clear the sensor without dismantling the flange.
• Liner Selection: Specifying PTFE (Teflon) liners for vacuum service lines (suction side of RAS pumps) can lead to liner collapse if the pipe goes into deep vacuum. Use polyurethane or hard rubber liners, or ensuring the PTFE is bonded/anchored for vacuum service.

O&M Burden & Strategy

Maintenance strategies differ between the technologies.

• Wiper Maintenance: Optical sensors (turbidity/TSS) usually have mechanical wipers. These rubber wipers wear out. A preventive maintenance (PM) task should be scheduled every 3-6 months to inspect and replace the wiper blade. A worn wiper smears the algae rather than removing it, causing signal drift.
• Desiccant Packs: Both Krohne and ABB transmitters (if not fully potted) often contain desiccant packs to manage humidity. These must be checked annually. Moisture ingress is the leading cause of electronics failure in outdoor bridge-mounted units.
• Magmeter Electrodes: In high-grease applications (scum pumping), electrodes can become insulated. While modern meters (Krohne’s Virtual Reference, ABB’s Coating Detection) can diagnose this, they cannot fix it. Periodic mechanical cleaning or chemical flushing may be required.

Troubleshooting Guide

• Symptom: Sludge blanket level reads “0” or “Full” continuously.
  Root Cause: For optical profilers, the cable may be tangled or the sensor stuck in the cleaning station. For sonar, the signal may be absorbed by a heavy “fluff” layer, causing loss of echo.
  Fix: Check the cable winding mechanism. Increase gain on sonar units (carefully).
• Symptom: Flowmeter reading wanders when pump is off.
  Root Cause: Ground loop or poor grounding rings.
  Fix: Ensure grounding rings are installed (especially on plastic pipe) and bonded to the sensor housing and earth ground.

Design Details & Calculations

Sizing Logic & Methodology

Proper sizing of flowmeters for clarifier service involves balancing velocity constraints.

The Velocity Sweet Spot:
Flowmeters on RAS/WAS lines should be sized to maintain a velocity between 3 ft/s and 10 ft/s (1 m/s to 3 m/s).

• < 3 ft/s: Risk of solids settling in the meter tube and grease coating the electrodes.
• > 10 ft/s: Excessive wear on the liner (abrasion) and potential for hydraulic noise.

Example Calculation:
Assume a WAS flow rate of 300 GPM.
Using a 4-inch meter: Area = 0.087 ft². Velocity = (300 / 448.8) / 0.087 ≈ 7.7 ft/s. (Acceptable)
Using a 6-inch meter: Area = 0.196 ft². Velocity = (300 / 448.8) / 0.196 ≈ 3.4 ft/s. (Marginal – risk of settling)
Decision: Select the 4-inch meter, even if the connecting piping is 6-inch, and use concentric reducers.

Specification Checklist

When writing the spec for Krohne vs ABB Clarification Equipment: Comparison & Best Fit, ensure the following items are explicitly requested:

1. Transmitter Enclosure: NEMA 4X / IP66 minimum; Stainless Steel or Polycarbonate (avoid painted aluminum in corrosive salt air).
2. Cable Length: Specify factory-potted cables of sufficient length to reach the junction box without field splicing (splicing introduces signal noise).
3. Sunshades: Mandatory for all outdoor transmitters.
4. Cleaning System: Mandatory “automatic mechanical wiper” or “air purge” for optical sensors.
5. Certifications: CSA/UL approval for the electrical components. Verification certificate (factory calibration) included in O&M manual.

Standards & Compliance

• AWWA M33: Flowmeters in Water Supply (Guidelines for magnetic flowmeter selection).
• ISO 1554: Wastewater treatment plant instrumentation standards.
• NEC (NFPA 70): Wiring methods for wet and corrosive locations (Article 500 if explosion-proof is required, though rare in open clarifiers).

Frequently Asked Questions

What is the main difference between Krohne OPTISYS and ABB Aztec for clarification?

The primary difference lies in the technology application. The Krohne OPTISYS SLM 2100 is widely recognized as a “sludge blanket profiler,” meaning it physically lowers a sensor on a cable to map the stratification layers of the clarifier. The ABB Aztec series (specifically ATS430) is primarily an optical turbidity/TSS sensor used for fixed-point monitoring (e.g., effluent quality or mixed liquor). While both measure solids, Krohne’s profiling capability is more specific to blanket level control.

Which flowmeter liner material is best for RAS/WAS applications?

For Return Activated Sludge (RAS) and Waste Activated Sludge (WAS), Polyurethane or Hard Rubber are typically the best fit. They offer excellent abrasion resistance against grit and sand found in sludge. PTFE (Teflon) is often overkill and can be susceptible to damage if vacuum conditions occur or if the liner is not bonded. PFA is a high-end alternative for high-temperature or chemically aggressive industrial sludge.

How often should clarifier sensors be calibrated?

Magnetic flowmeters (Krohne or ABB) are inherently stable and typically do not require “calibration” (adjustment) for years. However, they should undergo verification annually using the manufacturer’s verification tool (e.g., ABB VeriMaster or Krohne OPTICHECK) to confirm electronics health. Optical sensors (turbidity/sludge level) require more frequent attention; zero checks should be performed monthly, and comparison against grab samples (lab analysis) should be done weekly or bi-weekly to adjust the slope/gain.

Why do my sludge blanket readings fluctuate wildly?

Wild fluctuations are usually caused by either: 1) The rake arm passing under the sensor (causing a physical disturbance or echo interference), or 2) The sensor mistaking the “rag layer” (fluff) for the compact bed. To fix this, increase the signal damping (time constant) in the transmitter to smooth out the rake arm interference. If using an optical profiler, adjust the TSS threshold setting higher so it ignores the light fluff layer.

Is it better to use ultrasonic or optical sensors for sludge level?

For clarifiers with good settling characteristics, ultrasonic (sonar) is cheaper and requires no maintenance (no moving parts). However, for plants with bulking sludge, high fluff layers, or frequent process upsets, optical profiling (like the Krohne SLM) is superior. Optical sensors physically detect the density change, whereas sonar can be “fooled” by soft layers that absorb the sound wave, leading to “loss of echo” errors.

Conclusion

KEY TAKEAWAYS

• Clarification Equipment Context: Krohne and ABB supply the instrumentation (eyes and ears), not the mechanical scrapers.
• Flow Metering: Both offer Tier-1 magnetic flowmeters. ABB’s WaterMaster is noted for user-friendly verification; Krohne’s OPTIFLUX is noted for extreme durability in abrasive/noisy media.
• Blanket Level: Krohne’s OPTISYS SLM 2100 (optical profiler) is the industry benchmark for difficult settling conditions where sonar fails.
• Turbidity/Compliance: ABB’s Aztec series offers robust wiping mechanisms ideal for final effluent monitoring.
• Velocity Rule: Size RAS/WAS meters for 3-10 ft/s to prevent fouling; never size simply based on “line size.”
• Maintenance: Optical sensors must have automatic cleaning systems specified, or they will become O&M burdens.

In the evaluation of Krohne vs ABB Clarification Equipment: Comparison & Best Fit, the decision rarely comes down to a single “winner” for the entire plant. A nuanced engineering approach often yields the best results. For Sludge Blanket Level Profiling, Krohne holds a technical edge with the OPTISYS SLM 2100 due to its direct-measurement profiling capability, which is critical for automating RAS pumps in plants with variable sludge settling characteristics.

However, for Effluent Compliance and Flow Metering, ABB provides a highly competitive offering. The WaterMaster flowmeter’s onboard diagnostics and the Aztec turbidity system’s reliability make them favorites for regulatory reporting points. Engineers should focus less on brand loyalty and more on the specific physics of the measurement point: use optical profiling for the blanket, robust magmeters with proper liners for the sludge lines, and wiper-equipped optical sensors for the clear well.

Ultimately, the “best fit” is an instrument that survives the environment. By specifying NEMA 4X/IP68 enclosures, proper cleaning mechanisms, and correct hydraulic sizing, engineers can ensure that whichever manufacturer is selected, the clarifier operates with the visibility required for stable process control.

source https://www.waterandwastewater.com/krohne-vs-abb-clarification-equipment-comparison-best-fit/

Krohne vs Endress+Hauser Chemical Feed & Storage Equipment: Comparison & Best Fit

INTRODUCTION

In municipal and industrial water treatment, the “set it and forget it” mentality regarding chemical feed systems is a primary driver of operational inefficiency and compliance violations. While metering pumps and storage tanks are the muscles of the system, the instrumentation—specifically flow meters and level transmitters—acts as the nervous system. A surprising industry statistic suggests that up to 30% of chemical dosing costs are wasted due to overdosing caused by sensor drift, poor turndown ratios, or incorrect material specification. For engineers specifying plant upgrades or greenfield projects, the choice often narrows to two European giants: Krohne and Endress+Hauser (E+H).

This article provides a rigorous technical analysis of Krohne vs Endress+Hauser Chemical Feed & Storage Equipment: Comparison & Best Fit, focusing on the instrumentation that monitors and controls these critical process loops. These technologies are deployed in harsh environments, ranging from ferric chloride storage to sodium hypochlorite dosing and polymer injection. The consequences of poor selection in this category are severe: run-dry pump failures, chemical spills, inaccurate billing, and regulatory fines for disinfection byproducts or discharge violations.

Design engineers and plant directors must look beyond brand loyalty and evaluate these manufacturers based on electrode noise rejection, liner permeability, diagnostic capabilities, and lifecycle support. This guide dissects the engineering nuances required to select the right tool for the specific chemical application, ensuring process stability and cost containment.

HOW TO SELECT / SPECIFY

Selecting instrumentation for chemical feed and storage is fundamentally different from specifying general process water meters. The fluids are non-Newtonian, corrosive, conductive, or prone to off-gassing. Below are the engineering criteria essential for navigating the Krohne vs Endress+Hauser Chemical Feed & Storage Equipment: Comparison & Best Fit landscape.

Duty Conditions & Operating Envelope

The operating envelope for chemical feed is characterized by low flow rates and high turndown requirements. Unlike raw water intake lines, chemical feed lines often operate at velocities below 1 ft/s, which challenges the accuracy of standard electromagnetic flow meters. Engineers must verify the low-flow cutoff points and accuracy curves at the bottom 10% of the range.

Pressure surges from positive displacement metering pumps (diaphragm or peristaltic) create pulsating flows. The selected flow meter must have a high sampling frequency and advanced signal processing to average these pulsations without creating “noisy” output that destabilizes the PID control loop. For storage applications, temperature fluctuations significantly affect ultrasonic signal speed; therefore, integrated temperature compensation is mandatory.

Materials & Compatibility

Chemical compatibility is the single most common failure mode. Standard EPDM or NBR liners used in water applications will fail within weeks in Sodium Hypochlorite or Sulfuric Acid service.

• Liners: PTFE (Teflon) and PFA are industry standards for aggressive chemicals. However, for vacuum service (which can occur during tank unloading or pump suction conditions), PFA must be reinforced (often with a wire mesh or robust bonding) to prevent liner collapse.
• Electrodes: Hastelloy C is a baseline, but Tantalum, Platinum, or Titanium may be required for specific oxidizers. Krohne is noted for its ceramic measuring tubes in certain product lines, which eliminate the liner entirely, offering superior dimensional stability under temperature and pressure cycling.
• Permeability: Chlorine gas and other small-molecule chemicals can permeate standard PTFE liners over time, corroding the coils behind the liner. High-density/virgin PTFE or ceramic designs are critical countermeasures.

Hydraulics & Process Performance

In chemical feed skids, straight pipe runs are a luxury often unavailable due to space constraints. Engineers must evaluate the upstream and downstream straight-run requirements (expressed in Pipe Diameters, e.g., 5D/3D). Both Krohne and E+H offer “0D” or reduced-run models, but the physics behind how they achieve accuracy differs. Understanding the trade-off between installation footprint and measurement uncertainty is vital.

For Coriolis mass flow meters (often used for polymer or high-value chemicals), pressure drop becomes a critical design parameter. High-viscosity neat polymer can cause significant head loss through the bent tubes of a Coriolis meter. The specification must define the maximum allowable pressure drop at peak viscosity.

Installation Environment & Constructability

Chemical rooms are often classified as hazardous environments or, at a minimum, corrosive atmospheres. Plastic (polycarbonate) transmitter housings may degrade when exposed to UV or chemical fumes over decades. Aluminum or Stainless Steel housings (NEMA 4X/IP67 or IP68) are preferred.

Constructability note: Chemical feed lines are typically small bore (0.5″ to 2″). The weight of the flow meter relative to the PVC or CPVC piping is a structural concern. Adequate pipe support immediately adjacent to the meter flanges is required to prevent stress fractures in the plastic piping.

Reliability, Redundancy & Failure Modes

A primary failure mode in magmeters for chemical service is electrode coating. Non-conductive coatings (like grease or polymer buildup) insulate the signal, while conductive coatings can short the signal. Advanced diagnostics that monitor electrode impedance are necessary to trigger maintenance alarms before measurement is lost.

For level measurement in storage tanks, redundancy is best achieved by using dissimilar technologies. For example, a non-contact Radar level transmitter serves as the primary continuous measurement, while high-high and low-low mechanical float switches or vibrating forks provide hard-wired interlocks for spill prevention and pump protection.

Controls & Automation Interfaces

Modern chemical feed systems are moving away from simple 4-20mA analog signals toward digital protocols (EtherNet/IP, Modbus TCP, PROFIBUS) to extract diagnostic data. Both E+H and Krohne offer extensive digital integration.

The key differentiator is the depth of data available. Can the SCADA system read the “Electrode Coating Detection” status? Can the “Empty Pipe” alarm be distinguished from a general fault? Specifications must explicitly state which variables are to be mapped to the PLC, not just “digital communication provided.”

Maintainability, Safety & Access

Chemical storage tanks are confined spaces. Instrumentation that requires removal for calibration poses safety risks and operational downtime. Non-contact radar is superior to ultrasonic or hydrostatic pressure sensors in this regard, as radar is generally unaffected by vapors and does not require entering the tank for maintenance.

Remote mount transmitters are recommended for chemical feed applications. Keeping the electronics away from potential leaks at the flange connections protects the expensive components and allows operators to read displays safely from eye level rather than climbing ladders or crouching behind pump skids.

Lifecycle Cost Drivers

While the CAPEX difference between a high-end E+H Promag and a mid-range competitor might be 20%, the OPEX implications are vast. A meter with 0.2% accuracy versus 0.5% accuracy can save thousands of dollars annually in unnecessary chemical consumption for large plants. Additionally, “Heartbeat” (E+H) or “Opticheck” (Krohne) verification technologies allow for regulatory compliance verification without removing the meter from the line, saving significant labor hours and process interruption costs.

COMPARISON TABLES

The following tables provide a direct engineering comparison to assist in the Krohne vs Endress+Hauser Chemical Feed & Storage Equipment: Comparison & Best Fit decision process. Table 1 focuses on the specific product lines relevant to this sector, while Table 2 outlines application suitability.

Table 1: Manufacturer & Product Line Analysis

Technical Comparison of Primary Chemical Feed Instrumentation Lines

Feature / Category	Krohne (Key Lines: OPTIFLUX, OPTIWAVE)	Endress+Hauser (Key Lines: Proline Promag, Micropilot)	Engineering Considerations
Electromagnetic Flow (Magmeters)	OPTIFLUX 4000/5000: Known for robust ceramic liners (high purity, dimensionally stable). “Virtual Reference” grounding eliminates need for grounding rings in many apps.	Proline Promag W/H/P: Strong focus on diagnostics (Heartbeat Technology). Broad liner options (PFA, PTFE). Integrated grounding electrodes often available.	Ceramic liners (Krohne) are excellent for high corrosion/abrasion but brittle under mechanical shock. PFA (E+H) is versatile but requires protection against vacuum collapse.
Coriolis Mass Flow	OPTIMASS Series: Features Entrained Gas Management (EGM) which maintains measurement even with up to 100% gas entrainment (bubbles).	Proline Promass Q/F: Excellent density measurement accuracy. Heartbeat Technology provides coating detection and tube integrity verification.	EGM is a significant advantage for Krohne in applications where pumps may cavitate or chemicals off-gas (e.g., Sodium Hypo).
Radar Level (Storage)	OPTIWAVE Series: Strong portfolio in FMCW (Frequency Modulated Continuous Wave) radar, offering high accuracy in difficult tank geometries.	Micropilot FMR Series: 80 GHz technology handles condensation and buildup well. Bluetooth commissioning via SmartBlue app is highly operator-friendly.	80 GHz radar (available from both, but popularized by E+H) has a narrower beam angle, making it easier to install near tank walls or agitators.
Verification Technology	OPTICHECK: Portable service tool or integrated verification. Focuses on circuit and sensor integrity.	Heartbeat Technology: deeply integrated, continuous self-monitoring. Generates verification reports internally without external tools.	E+H Heartbeat is often preferred for automated compliance reporting; Krohne’s approach is robust but historically more service-tool oriented.
Maintenance Profile	High reliability in extreme chemical applications due to ceramic liner options. Lower electronic failure rates in high-vibration environments.	Modular electronics (easy swap). Diagnostic messages are clear text (NAMUR NE 107 compliant), simplifying troubleshooting for operators.	E+H generally offers a more user-friendly interface for less experienced technicians; Krohne is favored by purists for mechanical robustness.

Table 2: Application Fit Matrix

Best Fit Technology by Chemical Application

Application	Preferred Technology	Krohne Strength	Endress+Hauser Strength	Key Constraints
Sodium Hypochlorite (Feed)	Magmeter (Ceramic or PFA liner)	Ceramic liner is impervious to Cl2 permeation. EGM handles off-gassing bubbles.	Heartbeat detects electrode coating/buildup. Titanium electrodes standard option.	Off-gassing can disrupt ultrasonic/mag signals. Venting is critical.
Polymer (Neat/Dilute)	Coriolis (Mass Flow)	Single straight tube designs minimize pressure drop and shear.	Viscosity measurement allows for real-time dilution control.	Non-Newtonian fluid. Avoid gear meters; stick to Coriolis or Mag (if conductive).
Ferric/Alum (Storage)	Radar (Non-Contact)	Drop antennas prevent corrosion from condensation.	80 GHz radar ignores buildup on antenna; Bluetooth setup avoids opening tank.	Crystallization and fumes kill ultrasonic sensors. Use Radar.
Hydrofluosilicic Acid (Fluoride)	Magmeter	Specific material options for aggressive acid resistance.	Safety integrity levels (SIL) for overdosing protection.	Highly corrosive; Tantalum or Platinum electrodes often required.

ENGINEER & OPERATOR FIELD NOTES

Real-world experience often diverges from catalog specifications. The following notes are compiled from field observations regarding Krohne vs Endress+Hauser Chemical Feed & Storage Equipment: Comparison & Best Fit integration.

Commissioning & Acceptance Testing

Factory Acceptance Tests (FAT): For critical chemical dosing skids, require a wet calibration at the factory. Standard “dry” electronic calibration may not suffice for non-Newtonian fluids like polymer. Ensure the calibration certificate references the specific serial number of the unit.

Site Acceptance Tests (SAT):
1. Zero Point Calibration: This is critical for magmeters. The pipe must be full of liquid but at zero flow. A common error is zeroing the meter with an empty pipe or a partially full pipe, which offsets the entire calibration curve.
2. Conductivity Verification: Verify the chemical’s conductivity meets the minimum threshold (typically >5 µS/cm for water, but often >20 µS/cm for certain magmeters).
3. Damping Settings: Adjust the damping (time constant) to smooth out the pulsating flow from metering pumps. A value between 3 to 5 seconds is a typical starting point.

PRO TIP: When commissioning Radar Level Transmitters in plastic tanks, remember that radar waves can pass through the plastic roof. If there are metal pipes or cable trays above the tank, the radar might read them as the level. Use the “False Echo Suppression” or “Map-out” function in the transmitter to mask these signals.

Common Specification Mistakes

Oversizing the Meter: Engineers often match the flow meter size to the line size (e.g., 2-inch pipe = 2-inch meter). In chemical feed, flow rates are low. A 2-inch meter operating at 0.5 GPM will be at the very bottom of its range, resulting in poor accuracy and unstable control. Always size the meter based on the flow velocity range (ideally 2-10 ft/s), not the pipe size. It is common to reduce the line size at the meter (e.g., 2-inch pipe down to 0.5-inch meter) to increase velocity and accuracy.

Ignoring Grounding: Plastic pipes (PVC/CPVC) do not conduct electricity. For a magmeter to work, the fluid potential must be referenced to the sensor. Failing to specify grounding rings (or referencing electrodes) results in a wandering signal. Krohne’s “Virtual Reference” feature on specific models can eliminate the need for grounding rings, which is a major installation advantage in corrosive plastics.

O&M Burden & Strategy

Preventive Maintenance (PM):
– Monthly: Check transmitter display for error codes. Verify local reading matches SCADA.
– Quarterly: Inspect cable glands for chemical corrosion (chlorine attack on rubber seals).
– Annually: Perform electronic verification (Heartbeat/Opticheck). Compare totalizer readings against tank drawdown (volumetric check).

Spare Parts: Chemical feed sensors are critical path. Lead times for exotic materials (Tantalum electrodes, Ceramic liners) can be 8-12 weeks. Plants should stock one spare flow meter for each critical pipe size/type, or use “universal” spares where possible (e.g., stocking a high-spec unit that covers multiple lower-spec applications).

Troubleshooting Guide

• Symptom: Flow reading fluctuates wildly (noisy signal).
  • Root Cause: Air entrainment, electrode coating, or improper grounding.
  • Fix: Verify pump suction isn’t drawing air. Check grounding rings. Increase damping.
• Symptom: Level reading stuck at top of tank.
  • Root Cause: Radar lost echo or locked onto condensation near the antenna.
  • Fix: Check antenna condition. Increase “blocking distance.” Verify tank venting isn’t creating pressure that obscures the signal (rare for radar, common for ultrasonic).

DESIGN DETAILS / CALCULATIONS

Engineering the correct installation is as important as selecting the brand. Here are the design details pertinent to the Krohne vs Endress+Hauser Chemical Feed & Storage Equipment: Comparison & Best Fit discussion.

Sizing Logic & Methodology

To properly size a magnetic flow meter for chemical feed:

1. Determine Peak and Minimum Flow: Obtain the metering pump’s max capacity and the minimum required dose.
2. Calculate Velocity: Use the formula (V = frac{0.4085 times Q}{d^2}) where (V) is velocity (ft/s), (Q) is flow (GPM), and (d) is inner diameter (inches).
3. Target Velocity: Select a meter diameter that yields a velocity between 2 and 15 ft/s at normal operating flow.
   • Note: Velocities below 1 ft/s allow solids (lime, polymer) to settle and coat electrodes.
   • Note: Velocities above 20 ft/s can cause liner abrasion.
4. Check Pressure Drop: If reducing the meter size significantly, calculate head loss to ensure the metering pump has sufficient discharge head.

Specification Checklist

When writing the spec, ensure the following are included to avoid change orders:

• Liner Material: explicitly defined (e.g., “PFA or Ceramic”). Do not allow “Manufacturer Standard.”
• Electrode Material: defined based on chemical safety data sheet (SDS).
• Flange Rating: ANSI 150# is standard, but verify matches piping spec.
• Power Supply: 24VDC is safer and standard for instrumentation; 120VAC requires different conduit separation.
• Cable Length: For remote transmitters, specify the cable length required to reach the operator panel.
• Certifications: NSF-61 for all wetted parts if dosing into potable water.

Standards & Compliance

• AWWA C704: Standard for Propeller-Type Meters (less relevant here, but M6 manuals cover Magmeters).
• NSF/ANSI 61: Drinking Water System Components – Health Effects. Mandatory for potable water contact. Both Krohne and E+H offer NSF-61 certified liners.
• NEMA 4X / IP67: Minimum enclosure rating for washdown areas.
• NEC Article 500: Hazardous location classification (e.g., Methanol feed is Class 1, Div 1).

FAQ SECTION

What is the difference between Krohne’s Virtual Reference and E+H’s Grounding Electrodes?

In electromagnetic flow meters, the fluid potential must be equalized with the sensor body for accurate measurement. E+H typically uses a dedicated grounding electrode (a third electrode in the tube) or external grounding rings to achieve this. Krohne’s “Virtual Reference” allows the meter to operate without grounding rings by using an advanced input amplifier circuit that measures the potential difference relative to the ungrounded liquid. This reduces installation cost and leak points, particularly in plastic piping systems common in chemical feed.

How do you select between Ultrasonic and Radar for chemical storage tanks?

Radar is generally superior for chemical storage. Ultrasonic sensors rely on sound waves traveling through air; vapors from chemicals (like Hydrochloric Acid or Ammonia) change the speed of sound, causing measurement errors. Vapors can also absorb the signal. Radar (electromagnetic waves) is largely unaffected by vapor, pressure, or temperature changes in the headspace. While Ultrasonic is cheaper, the lifecycle reliability of Radar in chemical service makes it the best fit for Krohne vs Endress+Hauser Chemical Feed & Storage Equipment decisions.

What is the typical lifespan of a magmeter in Ferric Chloride service?

Ferric Chloride is highly abrasive and corrosive. A standard PTFE-lined magmeter might last 3-7 years depending on velocity and solids content. However, using a high-purity Ceramic measuring tube (a strength of Krohne’s Optiflux 5000 series) can extend this lifespan to 15+ years because the ceramic is nearly diamond-hard and chemically inert. The limitation is thermal shock; ceramic cannot handle rapid temperature spikes.

Does Endress+Hauser Heartbeat Technology replace wet calibration?

Not entirely, but it extends the interval. Heartbeat Technology performs an internal verification of the electronics and magnetic circuit with high coverage (often >95%). Regulatory agencies (like the EPA or state equivalents) are increasingly accepting “electronic verification” reports to extend the requirement for physical wet calibration or pull-checks. However, most permits still require a physical drawdown test or comparison against a master meter every 3-5 years.

Why is minimum flow velocity critical for chemical feed flow meters?

Operating a magmeter below 1 ft/s (0.3 m/s) significantly degrades accuracy (signal-to-noise ratio drops). More importantly, in chemical applications like lime slurry or polymer, low velocity allows buildup to form on the electrodes. Once electrodes are coated, the signal is insulated, causing the meter to read zero or drift. Sizing the meter smaller than the pipe to maintain >2 ft/s velocity is a standard engineering best practice.

How does “Entrained Gas Management” impact chemical dosing accuracy?

Sodium Hypochlorite and Hydrogen Peroxide naturally off-gas, creating bubbles in the feed line. Standard Coriolis or Magmeters may stall or output error values when bubbles pass through. Krohne’s EGM (Entrained Gas Management) allows the meter to maintain measurement even with high gas void fractions. E+H has similar multi-frequency technology. Without this feature, pumps may trip on “flow failure” alarms falsely due to bubbles, causing disinfection interruptions.

CONCLUSION

KEY TAKEAWAYS

• Don’t Oversize: Size flow meters based on fluid velocity (2-10 ft/s), not pipe diameter. This is the #1 design error in chemical feed.
• Material Matters: Use Ceramic liners for high abrasion/corrosion (Krohne strength) and PFA with grounding electrodes for general aggressive chems (E+H strength).
• Radar > Ultrasonic: For chemical storage, always specify Radar to avoid vapor/gas interference.
• Check the Grounding: In plastic piping, use grounding rings or Virtual Reference technology to ensure signal stability.
• Verification Saves Labor: Specify advanced diagnostics (Heartbeat/Opticheck) to reduce the frequency of confined-space tank entries or system shutdowns for calibration.

The choice within the Krohne vs Endress+Hauser Chemical Feed & Storage Equipment: Comparison & Best Fit matrix ultimately depends on the specific chemical profile and the plant’s maintenance philosophy. Both manufacturers offer top-tier, reliable instrumentation that exceeds the capabilities of lower-cost alternatives.

Krohne typically holds an edge in applications requiring extreme mechanical robustness, such as highly abrasive slurries or vacuum conditions where their fused ceramic liners provide unmatched durability. Their Virtual Reference technology also simplifies installation in the plastic piping systems ubiquitous in chemical feed.

Endress+Hauser often leads in terms of user interface, digital integration, and diagnostic accessibility. Their Heartbeat Technology is a benchmark for predictive maintenance, allowing operators to see electrode coating buildup before it causes a failure. For facilities prioritizing Industry 4.0 integration and ease of use for less specialized technicians, E+H is a strong contender.

Engineers should treat the flow meter and level transmitter not as accessories, but as the primary control authorities of the chemical feed system. Investing in the correct liner material, proper sizing, and advanced diagnostics yields a Return on Investment measured in process uptime, chemical savings, and regulatory compliance.

source https://www.waterandwastewater.com/krohne-vs-endresshauser-chemical-feed-storage-equipment-comparison-best-fit/

Krohne vs Thermo Fisher Anti-Cavitation Equipment: Comparison & Best Fit

Introduction

Cavitation is the silent killer of hydraulic efficiency and mechanical integrity in water and wastewater systems. For municipal and industrial engineers, the challenge is rarely just about selecting a pump; it is about selecting the instrumentation loop that can survive, detect, and mitigate the conditions that lead to cavitation. When incipient cavitation creates two-phase flow (bubbles and liquid) or when process upset conditions introduce entrained gas, standard flow measurement and protection equipment often fail, leading to blind control loops and catastrophic pump damage.

A surprising industry statistic suggests that over 30% of unplanned pump failures in wastewater treatment plants are directly linked to undetected cavitation or dry-run scenarios that standard instrumentation failed to catch in time. Engineers typically rely on discharge pressure or motor amperage to detect these issues, but these are lagging indicators. By the time the amperage drops, the damage to the impeller or seal may already be occurring. The more effective approach is utilizing advanced flow instrumentation capable of maintaining measurement integrity during entrained gas events, thereby allowing the control system (SCADA/PLC) to react before hydraulic failure occurs.

This article provides a technical deep-dive into the specific instrument capabilities of two major market players, focusing on the Krohne vs Thermo Fisher Anti-Cavitation Equipment: Comparison & Best Fit. While neither company manufactures “anti-cavitation valves” in the traditional sense, both provide critical sensing technologies—specifically Coriolis, Electromagnetic, and Ultrasonic flow meters—that engineers utilize to monitor cavitation-prone regimes.

In municipal lift stations, thickened sludge lines, and industrial chemical dosing skids, the ability of a meter to distinguish between signal noise and actual flow during gas entrainment is the difference between a nuisance alarm and a saved asset. Poor specification here results in “chattering” control valves, VFD hunting, and eventual equipment failure. This guide will assist engineers in specifying the correct technology for these harsh hydraulic environments.

How to Select / Specify

Selecting the right instrumentation to manage and monitor cavitation risks requires a departure from standard datasheet specification. Standard accuracy statements (e.g., “±0.5%”) usually apply only to single-phase liquids. In a Krohne vs Thermo Fisher Anti-Cavitation Equipment: Comparison & Best Fit analysis, the primary selection criteria must shift toward signal stability, damping capabilities, and multi-phase performance.

Duty Conditions & Operating Envelope

The operating envelope must be defined not just by flow rate, but by the hydraulic state of the fluid. Engineers must calculate the Net Positive Suction Head Available (NPSHa) versus Required (NPSHr) and identify where the intersection occurs relative to the measurement point.

• Void Fraction (Gas Content): Standard magnetic flowmeters often experience signal jumping when gas bubbles pass the electrodes. Coriolis meters can stall completely. You must specify the expected percentage of entrained gas (by volume). Technologies like Krohne’s EGM (Entrained Gas Management) are designed to maintain oscillation up to 100% gas entrainment, whereas standard ultrasonic meters from Thermo Fisher may rely on Doppler shifts which actually require bubbles, or Transit Time which fails with bubbles.
• Vapor Pressure & Temperature: In industrial wastewater or hot water applications, the margin to flashing is slim. The equipment selected must withstand rapid temperature fluctuations associated with collapsing vapor bubbles.
• Turndown Ratio: Cavitation often occurs during low-flow/high-head conditions (recirculation) or high-flow/run-out conditions. The selected device must maintain accuracy across the entire pump curve, not just the Best Efficiency Point (BEP).

Materials & Compatibility

Cavitation creates shock waves that can erode liner materials and damage sensor internals. When comparing equipment, material hardness and bond strength are paramount.

• Liner Adhesion: In magnetic flowmeters, vacuum conditions caused by cavitation or siphon effects can collapse liners. PFA liners with mechanical reinforcement (wire mesh) or ceramic liners are superior to standard PTFE liners in these applications.
• Sensor Tube Material: For Coriolis meters, Titanium tubes offer superior resistance to the fatigue caused by the high-frequency vibrations of cavitation compared to 316L Stainless Steel, though at a higher capital cost.
• Electrode Material: In wastewater with high solids and potential cavitation, signal noise is high. Utilizing low-noise electrodes (e.g., Tantalum or specialized stainless designs) can improve the signal-to-noise ratio.

Hydraulics & Process Performance

The interaction between the fluid mechanics and the sensor physics is the critical differentiator.

• Signal Damping: The device must offer adjustable damping (time constants). However, excessive damping hides the spikes that indicate the onset of cavitation. The best fit is equipment that offers “smart” filtering—rejecting hydraulic noise while reporting the fundamental flow variable.
• Diagnosis of Sound Speed: Advanced flowmeters can measure the speed of sound through the medium. A drop in the speed of sound is a primary indicator of micro-bubbles (incipient cavitation). Equipment that outputs this diagnostic variable allows the SCADA system to trim pump speed automatically.

Installation Environment & Constructability

Cavitation is frequently caused by poor piping geometry (elbows too close to pump suction). The monitoring equipment is often forced into these compromised locations.

• Straight Run Requirements: Thermo Fisher’s clamp-on ultrasonic meters generally require significant straight runs (10D-20D) to resolve the flow profile. If placed near a cavitating pump, the distorted profile will yield significant errors. Krohne’s electromagnetic and Coriolis meters generally require less straight run (0D-5D depending on the model), making them more suitable for tight pump rooms.
• Vibration Immunity: Cavitating pumps generate structural vibration. Coriolis meters, which rely on vibration for measurement, must have effective decoupling (massive splitters or adaptive filtering) to operate in this environment.

Reliability, Redundancy & Failure Modes

How does the device fail when the fluid turns into a foam or slug flow? This is the central question in the Krohne vs Thermo Fisher Anti-Cavitation Equipment: Comparison & Best Fit discussion.

• Measurement Stall: Many legacy Coriolis meters “freeze” the last known good value when density drops rapidly (gas entrainment). This is dangerous for control loops. The specification should require continuous measurement updates even during multi-phase events.
• Redundancy: For critical lift stations, engineers should consider using the flowmeter’s density output as a check against the pressure transmitter. If pressure drops and density drops simultaneously, cavitation is confirmed.

Controls & Automation Interfaces

The “equipment” is only as good as its integration into the control strategy.

• Diagnostic Outputs: Modern specifications should require the output of “Process Noise” or “Drive Gain” (for Coriolis) via Modbus, EtherNet/IP, or PROFIBUS. This value correlates directly to the energy required to drive the sensor tubes and is a proxy for aeration/cavitation levels.
• Response Time: The total loop time (sensor sensing + processing + output + PLC scan) must be faster than the time it takes for cavitation to damage a seal.

Lifecycle Cost Drivers

While instrumentation is a fraction of the pump cost, its failure leads to expensive pump repairs.

• CAPEX: Thermo Fisher clamp-on ultrasonics are generally lower CAPEX and non-intrusive, requiring no shutdown to install. Krohne Coriolis mass flow meters represent a high CAPEX.
• OPEX: The hidden OPEX is the cost of false alarms. If a meter falsely reports low flow due to bubbles, and the PLC shuts down the plant, the operational cost spikes. Equipment with advanced Entrained Gas Management (EGM) reduces these nuisance trips.

Comparison Tables

The following tables break down the technical differences between the primary technologies offered by these manufacturers in the context of difficult, cavitation-prone hydraulic regimes. Table 1 compares the technological approaches, while Table 2 focuses on application suitability.

Table 1: Technology Comparison – Performance in Multi-Phase/Cavitating Flow

Feature / Characteristic	Krohne (Focus: OPTIMASS / OPTIFLUX)	Thermo Fisher (Focus: Polysonic / Sx30)
Primary Technology	Coriolis Mass Flow (with EGM) & Electromagnetic	Ultrasonic (Doppler & Transit Time)
Response to Gas Bubbles (0-5%)	OPTIMASS: Continuous measurement; EGM algorithm maintains tube oscillation. OPTIFLUX: Generally stable, some noise on electrodes.	Doppler: Requires bubbles/solids to function (Good). Transit Time: Signal usually fails or degrades significantly.
Response to Slug Flow (>10% Gas)	Maintains operation; accuracy degrades but flow indication persists. Does not stall.	Signal loss is likely for Transit Time. Doppler may saturate or become erratic if signal attenuation is too high.
Process Noise Filtering	Advanced digital signal processing (DSP) specific to rejecting hydraulic noise.	Variable depending on model; often relies on signal strength averaging.
Cavitation Detection Capability	High. Can output “Drive Gain” or “Density” drops to SCADA to trigger pump protection.	Moderate. Can use “Signal Strength” or “Sound Speed” changes as a diagnostic.
Structural Vibration Immunity	Modern twin-tube designs are well-balanced, but extreme pump vibration requires careful mounting.	Clamp-on sensors are susceptible to pipe wall noise caused by cavitation; wetted transducers are better.
Maintenance Profile	Low. No moving parts. Clean-in-place (CIP) compatible.	Low for clamp-on (no process contact). Coupling gel may need refreshing on clamp-ons.

Table 2: Application Fit Matrix – Where to Specify Which Brand/Tech

Application Scenario	Best Fit Strategy	Krohne Strengths	Thermo Fisher Strengths
Return Activated Sludge (RAS) Risk: Air entrainment from aeration basins.	Electromagnetic or Doppler Ultrasonic	OPTIFLUX: Industry standard, robust liners, handles solids well.	Polysonic (Doppler): Excellent non-intrusive option for aerated liquids. Good retrofit solution.
Polymer Dosing Risk: Off-gassing, pulsating flow.	Coriolis Mass Flow	OPTIMASS: Unmatched ability to handle viscosity changes and gas bubbles without stalling.	Less applicable; ultrasonic signals struggle with viscous, attenuating polymers.
Raw Sewage Lift Stations Risk: Cavitation, ragging, vibration.	Electromagnetic	OPTIFLUX: Full bore design prevents clogging. Diagnostic functions detect electrode noise.	Doppler: Can work, but pipe liners (cement/epoxy) in old pipes block ultrasonic signals.
Effluent / Clean Water Pumping Risk: High head cavitation.	Transit Time Ultrasonic or Mag	OPTIFLUX: High accuracy, minimal pressure drop.	Transit Time: Very accurate for clean water; clamp-on allows easy verification of pump performance.

Engineer & Operator Field Notes

Specifying the hardware is only step one. The operational success of the Krohne vs Thermo Fisher Anti-Cavitation Equipment: Comparison & Best Fit largely depends on commissioning and maintenance strategies.

Commissioning & Acceptance Testing

When commissioning flow instrumentation in systems prone to cavitation, standard “zero and span” procedures are insufficient.

• Zero Calibration: Never perform a zero calibration while the pump is running, especially if the pump is vibrating. Ensure the pipe is full and the fluid is static. For Thermo Fisher clamp-on meters, ensure the acoustic coupling is verified with the diagnostic signal strength (“Signal Quality” > 50-60%).
• Drive Gain Baserunning (Coriolis): For Krohne OPTIMASS units, record the “Drive Gain” or “Tube Amplitude” when the system is running normally. Set a PLC alarm at 10-15% above this baseline. This differential will be your early warning system for cavitation (which requires more energy to drive the tubes).
• Sound Speed Validation (Ultrasonic): For Thermo Fisher units, validate the measured sound speed against the theoretical sound speed of the fluid at the current temperature. A significant deviation often indicates entrained air or poor sensor spacing.

Pro Tip: In wastewater applications, disable “Flow Cutoff” or “Low Flow Cutoff” during troubleshooting. These features often mask the erratic, low-amplitude signals that occur during the onset of cavitation, hiding the problem until it becomes severe.

Common Specification Mistakes

Engineers often copy-paste specifications from previous projects without analyzing the hydraulic profile.

• Over-Smoothing: Specifying a high damping value (e.g., 30 seconds) to get a “steady number” on the SCADA screen. This hides the hydraulic instability. Operators think the flow is stable while the pump is destroying itself. Keep damping low (< 3-5 seconds) and use the PLC to average for reporting, while using raw data for control logic.
• Ignoring Pipe Liners: Specifying clamp-on ultrasonic meters (Thermo Fisher) for cement-lined ductile iron pipe. The liner often delaminates or contains air gaps, blocking the acoustic signal. In these cases, a wetted electromagnetic meter (Krohne) is mandatory.

O&M Burden & Strategy

• Coupling Compound (Ultrasonic): Thermo Fisher clamp-on meters utilize a coupling gel. In hot pump rooms or outdoor applications, this gel can dry out over 1-2 years, causing signal loss. Maintenance schedules must include re-coupling.
• Electrode Coating (Mag Meters): Grease buildup in wastewater acts as an insulator. While Krohne meters often feature “virtual reference” or advanced diagnostics to detect coating, they eventually require cleaning. Specify meters with electrode cleaning circuits or removable measuring tubes if coating is rapid.

Troubleshooting Guide

Symptom: Flow reading spikes erratically.

• Diagnosis: Check the raw signal noise. If using a Krohne Mag meter, look at the electrode noise value. If high, it could be solids impingement or cavitation bubbles collapsing near the electrode.
• Test: Throttle the discharge valve slightly (increasing backpressure). If the noise disappears and the flow signal stabilizes, the issue was cavitation, not electrical noise.

Design Details / Calculations

To properly apply Krohne vs Thermo Fisher Anti-Cavitation Equipment: Comparison & Best Fit principles, engineers must understand the sizing logic that governs multi-phase flow capability.

Sizing Logic & Methodology

The goal is to size the meter such that the fluid velocity is high enough to carry entrained gas bubbles through the sensor (preventing accumulation/slugging) but not so high that it creates additional pressure drop leading to flashing.

1. Determine Minimum Velocity: In vertical lines, fluid velocity must exceed the “bubble rise velocity.” A rule of thumb for wastewater is to maintain > 3-5 ft/s (1-1.5 m/s) through the meter.
2. Calculate Pressure Drop: Use the manufacturer’s sizing software. Ensure that the pressure at the meter outlet remains above the fluid’s vapor pressure plus a safety margin (typically 5 psi).
   Check: $P_{outlet} > P_{vapor} + P_{margin}$
3. Evaluate Sigma (Cavitation Index): For control valves or restrictions near the meter:
   $sigma = (P_{upstream} – P_{vapor}) / (P_{upstream} – P_{downstream})$
   If $sigma$ is approaching 1.0, measurement instability is guaranteed. Move the flowmeter upstream of the restriction (valve) if possible to keep it in the high-pressure zone.

Common Mistake: Installing flowmeters on the suction side of a pump to “monitor suction conditions.” This creates a pressure drop exactly where you cannot afford it (lowering NPSHa). Always install flowmeters on the discharge side, unless strictly necessary and sized with negligible pressure drop (e.g., full-bore mag meter).

Specification Checklist

When writing the Division 40 specification, include:

• For Gas-Prone Applications: “Flowmeter shall utilize digital signal processing capable of maintaining measurement during two-phase flow events up to 20% gas by volume (Void Fraction).”
• Diagnostic Output: “Transmitter shall provide a secondary analog or digital output proportional to signal strength, drive gain, or sound speed to facilitate predictive maintenance.”
• Empty Pipe Detection: “Sensor must include active empty pipe detection to prevent false totalization during dry-run conditions.”

Standards & Compliance

• AWWA M6: Manual of Water Supply Practices for Water Meters.
• ISO 4064: Water meters for cold potable water and hot water.
• NAMUR NE 107: Self-monitoring and diagnosis of field devices. Specifying NE 107 compliance ensures the meter communicates errors (like “Entrained Gas”) in a standardized format.

FAQ Section

What is Entrained Gas Management (EGM) in Krohne flowmeters?

Entrained Gas Management (EGM) is a proprietary technology developed by Krohne for their OPTIMASS Coriolis flowmeters. Historically, Coriolis meters would stall (stop measuring) when gas bubbles dampened the tube vibration. EGM allows the meter to maintain tube oscillation and continue measuring mass flow and density even with entrained gas levels ranging from 0% to 100% (slug flow). This is critical for applications like polymer dosing or unloading tankers where air ingestion is common.

Can Thermo Fisher ultrasonic meters measure cavitating flow?

It depends on the technology used. Thermo Fisher’s Doppler ultrasonic meters (like the Polysonic series) actually require discontinuities like bubbles or solids to reflect the signal, so they may function well in aerated wastewater. However, their Transit Time meters (designed for clean liquids) will often fail or lose signal if significant cavitation bubbles interrupt the acoustic beam. Selection must be based on the specific type of ultrasonic technology.

How does a flowmeter help prevent pump cavitation?

The flowmeter itself does not prevent cavitation, but it acts as the “eyes” of the control system. By monitoring diagnostic variables—such as a drop in the speed of sound (Ultrasonic) or an increase in drive gain (Coriolis)—the PLC can detect the onset of micro-bubbles before audible cavitation occurs. The control logic can then automatically reduce pump speed (VFD) or throttle a valve to restore NPSH margin, saving the pump from damage.

What is the difference between Krohne and Thermo Fisher for wastewater applications?

Krohne is generally more focused on inline, wetted instrumentation like Electromagnetic (Mag) meters and Coriolis meters, which are standard for permanent, high-accuracy wastewater process control. Thermo Fisher is often favored for portable or non-intrusive applications using clamp-on ultrasonic technology, or for analytical measurements (pH, DO). For a permanent sludge line flowmeter, a Krohne Mag meter is the typical engineering choice; for a temporary check of a raw water line, a Thermo Fisher clamp-on is ideal.

Why is magnetic flowmeter signal noise a problem during cavitation?

Cavitation bubbles collapsing near the electrodes of a magnetic flowmeter create electrical spikes that look like flow. This results in a “noisy” signal where the flow rate jumps erratically on the SCADA screen. If the noise is severe, it can mask the true flow rate or cause false totalization. High-end meters (like Krohne’s OPTIFLUX) use specific filtering algorithms and high-frequency excitation to distinguish this hydraulic noise from the actual flow signal.

What is the typical cost difference between these technologies?

Cost varies by pipe size. For small diameters (< 2 inch), a Krohne Coriolis meter is significantly more expensive ($3,000-$6,000+) than a simple mag meter ($1,000-$2,000). Thermo Fisher clamp-on ultrasonic meters have a fixed cost regardless of pipe size (typically $4,000-$8,000 depending on features), making them very expensive for small pipes but highly cost-effective for large pipes (> 24 inch) where inline mag meters become extremely costly.

Conclusion

Key Takeaways

• Define “Anti-Cavitation”: In this context, it refers to instrumentation that can survive and detect cavitation to protect pumps, not valves that prevent it physically.
• Technology Fit: Use Krohne Coriolis (with EGM) for high-value chemical dosing with gas risk. Use Thermo Fisher Doppler Ultrasonic for non-intrusive monitoring of aerated sludge/wastewater.
• Avoid Transit Time: Do not specify Transit Time ultrasonic meters for pump suction/discharge where cavitation is expected; the signal will likely fail.
• Use Diagnostics: Specification must require the output of diagnostic variables (Drive Gain, Signal Strength, Speed of Sound) to the SCADA system for predictive pump protection.
• Installation Matters: Avoid placing clamp-on meters on lined pipes or near elbows in cavitation-prone lines. Inline Mag meters offer the best reliability for permanent installations in tight pump rooms.

The decision between Krohne vs Thermo Fisher Anti-Cavitation Equipment: Comparison & Best Fit ultimately comes down to the criticality of the measurement and the physical access to the pipe. For permanent, mission-critical control loops in wastewater lift stations or sludge processing—where the fluid may contain entrained gas or solids—Krohne’s electromagnetic and EGM-equipped Coriolis meters offer superior resilience and integration capabilities. They provide the robustness required to survive the hydraulic shocks of cavitation while maintaining measurement authority.

However, for retrofit applications, temporary troubleshooting of suspected cavitation issues, or monitoring large-diameter raw water lines where cutting the pipe is impossible, Thermo Fisher’s ultrasonic solutions provide an invaluable toolset. The “Best Fit” is achieved not by brand loyalty, but by matching the sensor physics (Conductivity vs. Acoustics vs. Coriolis Force) to the specific void fraction and turbulence of the application. Engineers who specify based on these hydraulic realities will reduce lifecycle costs and extend the operational life of their pumping assets.

source https://www.waterandwastewater.com/krohne-vs-thermo-fisher-anti-cavitation-equipment-comparison-best-fit/