Krohne Variable area flowmeters DK46 DK47 DK48 DK800
The DK46, DK47, DK48, and DK800 are glass tube variable area (VA) flowmeters from KROHNE, designed for monitoring and adjusting extremely small flow rates of liquids and gases. They are particularly suited for sample flow monitoring in analyzer systems and gas chromatographs, as well as for measuring liquids and gases in laboratories and pilot installations. The meters operate without auxiliary power, offer integrated needle valves, and are available with SIL 2 functional safety certification.
Key Features and Benefits
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Optimized for Very Low Flows: Designed for liquid flows from ≥0.04 l/h (≥0.1 GPH) and gas flows from ≥5 Nl/h (0.22 SCFH), making them ideal for sample flow monitoring and fine dosing applications.
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Simple, Cost-Effective Measurement: The low-cost measuring principle requires no auxiliary power. The medium is visible through the borosilicate glass measuring tube, and flow is read directly from the scale at the float position.
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Integrated Needle Valve: A high-quality needle valve in the foot or head piece enables precise flow regulation directly at the measuring point.
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SIL 2 Functional Safety: Suitable for use in Safety Instrumented Systems with SIL 2 capability. In redundant design (1oo2), the meters can be used in SIL 3 applications as type A devices.
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Multiple Material and Connection Options: Process connections available in stainless steel, brass, or PVDF. Standard connections are G¼ or ¼” NPT internal thread, with other options available on request.
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Hazardous Area Approvals: Approved for use in hazardous areas with ATEX, IECEx, FM, and NEPSI certifications.
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No Wearing Parts: The float-based measuring principle has no moving parts subject to wear, ensuring long service life and minimal maintenance.
Technical Specifications (at a Glance)
| Specification | DK46 | DK47 | DK48 | DK800 |
|---|---|---|---|---|
| Accuracy (VDI/VDE 3513-2) | 4.0% of measured value | 2.5% of measured value | 1.0% of measured value | 2.5% of measured value |
| Liquid Flow Range | 0.065 to 42 GPH | 0.13 to 25 GPH | 0.01 to 25 GPH | 0.065 to 42 GPH |
| Gas Flow Range | 0.022 to 45 SCFH | 0.06 to 30 SCFH | 0.025 to 110 SCFH | 0.018 to 180 SCFH |
| Process Temperature | –5 to +100 °C | –5 to +100 °C | –5 to +100 °C | –5 to +100 °C |
| Max. Process Pressure | 10 bar (SS/brass); 4 bar (PVDF) | 10 bar (SS); 4 bar (PVDF) | 10 bar | 10 bar (SS); 4 bar (PVDF) |
| Measuring Tube | Borosilicate glass | Borosilicate glass | Borosilicate glass | Borosilicate glass |
| Fittings Material | Stainless steel, brass, PVDF | PVDF, stainless steel | Stainless steel, brass | Stainless steel, PVDF |
| Process Connection | G¼, ¼” NPT | G¼, ¼” NPT | G¼, ¼” NPT | G¼, ¼” NPT |
| SIL Certification | SIL 2 (1oo2: SIL 3) | SIL 2 (1oo2: SIL 3) | SIL 2 (1oo2: SIL 3) | SIL 2 (1oo2: SIL 3) |
| Ex Approvals | ATEX, IECEx, FM, NEPSI | ATEX, IECEx, FM, NEPSI | ATEX, IECEx, FM, NEPSI | ATEX, IECEx, FM, NEPSI |
The DK46, DK47, DK48, and DK800 provide reliable, cost-effective low-flow measurement for analyzer systems, purge panels, laboratories, and pilot installations, combining glass tube visibility, integrated flow regulation, and SIL 2 safety capability in a compact package.
Krohne Variable area flowmeters DK46 DK47 DK48 DK800
The DK46, DK47, DK48, and DK800 are glass tube variable area flowmeters from KROHNE, designed for monitoring and adjusting extremely small flow rates of liquids (from ≥0.04 l/h or ≥0.1 GPH) and gases (from ≥5 Nl/h or 0.22 SCFH). They are particularly useful for sample flow monitoring in analyzer systems and gas chromatographs, or for measuring liquids and gases in laboratories and pilot installations.
The flowmeters operate on the variable area (VA) measuring principle. The medium flows upward through a tapered borosilicate glass measuring tube, lifting a float. The float’s height position corresponds to the flow rate and is read directly from the scale engraved on the glass tube. The medium is fully visible during measurement, providing immediate visual verification of flow. The measuring principle requires no auxiliary power supply, making the meters cost-effective and simple to install.
Each model in the series offers different accuracy levels and flow ranges to suit specific application requirements. The DK46 provides an accuracy of 4.0% of measured value per VDI/VDE 3513-2, with stainless steel fittings as standard for industrial applications. The DK47 offers improved accuracy of 2.5% of measured value, with PVDF fittings suitable for corrosive media. The DK48 delivers the highest accuracy at 1.0% of measured value for demanding laboratory and pilot applications. The DK800 provides 2.5% accuracy with a broader gas flow range up to 180 SCFH.
The meters feature an integrated high-quality needle valve in the foot or head piece, enabling precise flow regulation directly at the measuring point without additional valves. The valve allows fine metering of very small volumes of liquids and gases. A differential pressure regulator option is also available to provide constant flow rates in case of varying inlet or outlet pressures.
The glass tube construction allows direct visual observation of the medium, with flow values read at the float height on the engraved scale. The meters are available with different glass tube and installation lengths ranging from 90 to 325 mm (3.55 to 12.8 inches). A maximum of two NAMUR limit switches or a 3-wire digital output can be provided for alarm or control functions.
The DK46/47/48/800 series holds SIL 2 functional safety certification, making them suitable for use in Safety Instrumented Systems. As type A devices, they can be used in SIL 3 applications when installed in redundant (1oo2) configurations. Typical safety-related applications include sample flow monitoring for process analyzer systems, gas or liquid supply monitoring for mechanical sealing systems, purging monitoring for measuring systems, and nitrogen inertization.
The meters are approved for use in hazardous areas with ATEX, IECEx, FM, and NEPSI certifications. Panel mounting blinds and supports are available for installation on purge panels or similar applications. A laboratory support is also available to convert the flowmeter into a desktop unit for laboratory use.
The DK46, DK47, DK48, and DK800 provide reliable, cost-effective low-flow measurement for analyzer systems, purge panels, laboratories, and pilot installations, combining glass tube visibility, integrated flow regulation, and SIL 2 safety capability in a compact package.