『Keyence Gas Flow Meter Technology: Compact Inline Thermal Dispersion Transmitters for Compressed Nitrogen』Related information(clamp on meter|electromagnetic meter|venturi meterrotameter|orifice meter|ultrasonic flow meter|mass flow meter|coriolis mass flow meter|coriolis flow meter|magnetic flow meter|magmeter flow meter|magflow flow meter|mag meter flow meter|electromagnetic flow meter|vortex flow meter|turbine flow meter|thermal mass flow meter|thermal flow meter|rotameter flow meter)
Keyence Gas Flow Meter Technology: Compact Inline Thermal Dispersion Transmitters for Compressed Nitrogen
Quick Answer: Thermal dispersion transmitters are the most practical choice for compressed nitrogen flow measurement. Silver Instruments supplies compact inline models with 4-20 mA HART output, ATEX Zone 1 options, and direct mass flow readings in kg/h or Nm3/h. You do not need separate pressure and temperature compensation.
Why Compressed Nitrogen Flow Measurement Needs Thermal Dispersion
Compressed nitrogen is dry, clean, and non conductive. This rules out electromagnetic flow meters. Turbine meters can work but moving parts wear out in dry gas. Vortex meters need a minimum velocity and enough straight pipe. Thermal dispersion mass flow meters do not need moving parts. They measure mass flow directly. Most engineers skip the extra pressure and temperature transmitters because nitrogen mass flow is what the process needs.
Here is the thing. A thermal dispersion transmitter uses two PT100 sensors in the gas stream. One sensor reads the gas temperature. The other sensor is heated. The flow cools the heated sensor. The cooling rate has a direct relation to mass velocity. The electronics convert this into a mass flow signal.
Keyence gas flow meter technology has made the market aware of compact sensing for compressed air and nitrogen. Silver Instruments supplies a full inline thermal mass flow meter for pipe sizes DN15 to DN50. It fits into the same installation envelope and gives direct mass flow output.
How a Compact Inline Thermal Transmitter Works
The transmitter body fits directly into the pipe section or as an insertion probe with a compression fitting. For small lines from DN15 to DN25 we recommend inline flow bodies. For DN32 to DN50 you can use either inline or insertion types. The inline body gives better accuracy in short straight runs.
Two PT100 RTDs are sealed in stainless steel 316L thermowells. The reference sensor measures gas temperature at the inlet. The heated sensor runs about 30 °C above the gas temperature. As nitrogen flows across the heated sensor, heat is carried away. The control circuit adjusts power to keep the temperature difference constant. The required power corresponds to mass flow.
You get direct readings in kg/h, Nm3/h, or standard liters per minute. No need for pressure and temperature compensation. The output is 4-20 mA HART as standard. Modbus RTU is optional. Accuracy is typically ±1.5 percent of reading plus ±0.5 percent of full scale. Response time is under 2 seconds.
Key Installation Parameters for Nitrogen Service
Specify these values before you order: pressure in bar, temperature in °C, pipe size in DN, and flow range. For compressed nitrogen most systems run between 6 bar and 16 bar. Gas temperature is often 20 °C to 60 °C. Small purge lines operate at DN15. Main distribution headers may reach DN50 or larger.
We have seen this on customer sites many times. A paint manufacturer in Vietnam asked for a DN25 nitrogen flow meter at 8 bar. They wanted to monitor nitrogen blanketing flow into solvent storage tanks. The process needed a compact transmitter with no moving parts and a local display. The Silver Instruments inline thermal dispersion transmitter fit directly into the 25 mm stainless steel line. It gave stable readings from 2 kg/h up to 120 kg/h.
For compressors and nitrogen generators, the flow meter should be installed after the dryer and filter. The gas must be dry and free of oil mist. Thermal dispersion sensors are sensitive to liquid droplets. Install the meter in a straight pipe section with at least 10 pipe diameters upstream and 5 diameters downstream. If you have less straight run, use a flow conditioner or move the meter to a longer run.
Silver Instruments Model Range and Outputs
Silver Instruments offers thermal mass flow meters for compressed nitrogen in inline and insertion configurations. Small sizes are DN15, DN20, DN25, DN32, DN40, and DN50. Larger insertion models handle DN65 to
The transmitter is available with an integrated display or a remote display. The electronics enclosure can be aluminum or stainless steel. Hazardous area approvals include ATEX Zone 1 and Zone 2 for gas atmospheres. Many customers in the Middle East and Latin America order the ATEX Zone 1 version for compressor stations and refinery purging.
Outputs are 4-20 mA HART, pulse, and RS485 Modbus. You can also get two relay alarms for low flow and high flow switching. The local display shows mass flow, total flow, gas temperature, and alarm status. Setup is done with three push buttons. No special software is required for basic commissioning.
Typical Applications in Specific Industries
Food and beverage plants use nitrogen to purge oxygen from packaging lines. A snack food producer in Indonesia installed DN15 inline thermal meters on each nitrogen injection point. The compact body fit inside the machine frame. The 4-20 mA signal went directly to the PLC. The totalizer helped them track nitrogen cost per package.
Electronics manufacturers use nitrogen during reflow soldering. The flow rate must stay constant to prevent oxidation. A contract electronics assembler in Australia needed a DN20 meter with a fast response. The thermal dispersion transmitter detected flow changes within one second. This allowed the PLC to shut down the oven if nitrogen flow dropped below a setpoint.
Oil and gas operators use nitrogen for pipeline purging and pressure testing. A service company in Oman bought insertion thermal meters for temporary nitrogen skids. The meters survived outdoor installation because the electronics were rated IP67. The 4-20 mA HART signal enabled remote monitoring from the control cabin.
Chemical plants in Latin America use nitrogen blanketing on reactors. The flow range is often low, below 50 kg/h. The thermal dispersion meter gives better turndown than a vortex meter in this low velocity zone. A 100:1 turndown is common. This means one meter covers both normal purge flow and high trip flow.
FAQ: Compressed Nitrogen Flow Measurement
What is the minimum pipe size for a thermal dispersion nitrogen flow meter?
DN15. Smaller tube sizes can be quoted as special versions.
Do I need pressure and temperature compensation for compressed nitrogen mass flow?
No. Thermal dispersion mass flow meters measure mass flow directly. The transmitter compensates internally for gas temperature changes. You only need to set the gas type in the menu.
Can the transmitter be used in hazardous areas?
Yes. Silver Instruments offers ATEX Zone 1 and Zone 2 approvals for gas atmospheres. For nitrogen service in oil and gas, specify the Ex d version.
What is the output signal?
The standard output is 4-20 mA HART. Optional outputs include RS485 Modbus RTU, pulse, and two relay alarms.
How do I request a quote for a nitrogen flow meter?
Send us your pressure in bar, temperature in °C, pipe size in DN, and flow range. Also mention the required output and hazardous area classification.
Request a Quote with Your Process Data
Send us your pressure (bar), temperature (°C), pipe size (DN), and flow range. Also include the gas type, required output, and hazardous area class. Our engineers will select the correct inline or insertion thermal mass flow meter for your compressed nitrogen line.
Contact Silver Automation Instruments today.
Tel: +86-25-68650347
Whatsapp: +86-25-52155837
WeChat: +86 15365082610
We respond to most technical quotes within 24 hours. Many customers in Southeast Asia, Australia, Latin America, Africa, and the Middle East already use our thermal dispersion meters for nitrogen, compressed air, and natural gas. You can get the same direct reading without excess piping modifications.
Hot Blog
Related AD
