KROHNE DK32/34 Variable Area Flowmeter | Metal Tube Purgemeter for Low Flow

The Industry Standard for Reliable Sample Flow Monitoring and Dosing

The KROHNE DK32/34 is a world-renowned variable area (VA) flowmeter designed for the high-precision measurement of low-flow liquids and gases. Engineered for durability in extreme process environments, this metal tube rotameter thrives where glass meters fail, handling pressures up to 220 barg (3190 psig) and temperatures up to +200°C. Whether used in nitrogen inertization, gas analyzer sample lines, or chemical injection skids, the DK32/34 provides a stable, mechanical local indication that requires no auxiliary power, ensuring safety and continuity in mission-critical applications.

High-Pressure Flow Monitoring for Analyzer Panels and Purge Systems

In the oil and gas and chemical industries, maintaining a constant sample flow to analyzers is vital. The DK32/34 excels in sample flow monitoring, featuring an integrated high-precision needle valve for fine adjustment. For systems where inlet or outlet pressures fluctuate, the DK32 can be equipped with a mechanical differential pressure regulator. To build a high-reliability analyzer conditioning system, many engineers integrate this purgemeter with the [Rosemount 3051S Pressure Transmitter] to provide real-time inlet pressure diagnostics alongside flow data.

SIL 2 Certified Safety for Hazardous Area Instrumentation

Safety and reliability are built into the core of the DK series. The DK32/34 is SIL 2 certified (IEC 61508) and is suitable for use in Safety Instrumented Systems (SIS). For applications requiring a digital bargraph indicator or higher accuracy (±2.5%) in hazardous zones, we recommend upgrading to the [KROHNE DK37 M8]. For trace-level analysis, we offer optional SilcoNert®2000 surface passivation, preventing the adsorption of moisture or sulfur components onto the stainless steel surfaces.

📊 Comprehensive Technical Specifications: KROHNE DK32/34

1. Measurement Performance

2. Operating Conditions & Physical Limits

3. Materials of Construction

4. Process Connections & Mounting

5. Electronics & Communication

6. Safety, Standards & Compliance

🛠 Advanced Engineering Insights for DK32/34

1. Solving the "Fluctuating Pressure" Problem

In many analyzer systems, the supply pressure drops as other equipment on the same line cycles on or off. For a standard VA meter, this causes the float to drop, leading to inaccurate dosing. By specifying a mechanical differential pressure regulator with your DK32, the meter maintains a constant flow rate regardless of pressure changes, ensuring your analyzer is always correctly primed.

Pro-Tip for System Integrators: To achieve full transparency of your conditioning system’s health, we recommend pairing the DK series with a [Rosemount 3051S Pressure Transmitter]. This allows for real-time inlet pressure diagnostics and automated alarming at the DCS level, preventing undetected sample loss

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2. Trace Analysis & Adsorption Prevention

When measuring sulfur or moisture at the parts-per-billion (ppb) level, standard stainless steel surfaces can "steal" molecules from the flow through a process called adsorption. The SilcoNert®2000 passivation creates a chemically inert barrier inside the DK32 tube. This ensures that the gas reaching your sensor is exactly what is in the process line, preventing dangerous delays in analytical response time.

Complementary Solution: For ultra-pure liquid dosing applications within the same analytical skid, the [KROHNE OPTIFLUX 6400] provides a perfect high-precision complement. Its PFA liner and electromagnetic principle offer the same level of chemical inertness for liquids as the SilcoNert®2000 does for gases

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3. Zero Straight Run Advantage (Space Efficiency)

The DK32/34 is a purely mechanical device that does not rely on fluid velocity profiles for measurement. Therefore, it requires zero straight pipe runs (0D). You can install a 90-degree elbow or a valve directly at the meter’s inlet without affecting the ±4% accuracy.

Comparative Sizing Note: This "0D/0D" installation capability is a massive advantage over standard ultrasonic or electromagnetic meters in tight-packaged OEM skids. If your project also requires larger-scale water measurement where space is equally limited, the [KROHNE WATERFLUX 3400] utilizes similar zero-diameter straight-run technology to provide full-bore accuracy in compact footprints.

Frequently Asked Questions

• Q: What is the main difference between the DK32 and DK34 models?

  • A: The primary difference lies in the process connection orientation. The DK32 features horizontal connections (G or NPT), making it ideal for compact panel mounting. The DK34 has vertical connections, which is preferred for straight in-line piping installations.

• Q: Why is a differential pressure regulator recommended for the DK32/34?

  • A: If your process experiences inlet or outlet pressure fluctuations, the float in a standard VA meter may drift. A differential pressure regulator maintains a constant flow rate regardless of these variations, ensuring stable sample flow to analyzers and protecting sensitive downstream equipment.

• Q: Can the DK32/34 be used in trace-level sulfur or moisture analysis?

  • A: Yes. By specifying the optional SilcoNert®2000 surface passivation, the stainless steel internals become chemically inert. This prevents the adsorption of trace molecules (like H2S or moisture) onto the metal surfaces, ensuring the sample composition remains unchanged for accurate analytical results.

• Q: Does this meter require straight pipe runs for installation?

  • A: No. One of the biggest advantages of the DK32/34 is the 0D/0D installation capability. Because it is a mechanical variable area meter, it does not rely on fluid velocity profiles, allowing you to install elbows or valves directly at the inlet without affecting accuracy.