Current position > News detail
『Yokogawa Mass Flow Meter: Thermal and Coriolis Gas Calibration Manuals』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)
Yokogawa Mass Flow Meter: Thermal and Coriolis Gas Calibration Manuals for Gas Service
Quick Answer: The Yokogawa thermal and Coriolis gas calibration manuals focus on zero point adjustment, gas density correction, and flow factor verification. Engineers should always verify zero under process pressure for a Coriolis meter and confirm that the thermal meter gas type matches the actual process gas. Silver Automation Instruments can supply calibrated mass flow meters and field support if you send your gas type, pressure in bar, temperature in °C, pipe size in DN, and flow range in kg/h.
What the Yokogawa Calibration Manuals Cover
The thermal mass flow meter manual usually covers air and nitrogen calibration, gas conversion factors, temperature compensation, and zero cut. The Coriolis manual covers live zero, density calibration, totalizer reset, and signal output check. In gas service, the manuals specify process pressure limits. A DN25 Coriolis meter may be calibrated for 0.1 to 4.0 MPa gas line pressure. A thermal meter often has a stated reference condition at 101.325 kPa and 0 °C or 20 °C depending on the model. This difference matters because gas density changes with pressure and temperature.
Most engineers skip this part. They set the gas name in the transmitter and assume the meter is ready. That assumption causes errors of 2 to 5 percent on some thermal meters. We have seen this on customer sites many times. Last year a customer in Vietnam asked us why a biogas thermal meter read 8 percent higher than a reference meter. The meter was set to natural gas. The manual listed biogas as a separate gas code. After correcting the gas code, the reading matched within 1 percent.
Thermal Gas Calibration Steps That Matter in the Field
The first step is to confirm the actual gas type. Common gases include air, nitrogen, oxygen, carbon dioxide, argon, methane, natural gas, and biogas. The Yokogawa thermal meter stores gas curves for many gases. If the process gas is not the same as the calibration gas, use the meter factor from the calibration manual. Do not assume the factory default matches your process.
Check the installation before you adjust the meter. A thermal insertion flow meter needs enough straight run. Many manuals specify 20 DN upstream and 10 DN downstream. A short run near a butterfly valve or a control valve causes turbulence. The meter may read high or low. In one case a water treatment customer in the Middle East reported unstable gas flow readings. The manual specified 20 DN straight run upstream but the site had only 6 DN. After moving the probe, the reading stabilized.
Set the zero correctly. Close the isolation valve and wait 60 seconds. Run the zero function from the display or HART. Temperature compensation should use the built in PT100 sensor if the meter includes one. If not, enter process temperature manually. The manual often shows a table for gas density versus pressure and temperature. Use that table to verify the reference condition. A mismatch of 20 °C can shift the reading by over 6 percent on some thermal meters.
Coriolis Gas Calibration Zero and Density Checks
For a Coriolis meter in gas service, zero point adjustment has the largest impact on low flow accuracy. Install the meter in the pipe, fill it with gas at process pressure, close the downstream valve, and let flow stop completely. Wait 30 to 120 seconds for temperature and pressure to stabilize. Then run the zero procedure from the local display or HART. The Yokogawa manual uses a stable zero value. A zero shift of 0.0002 g/cm³ can create a visible error at low gas flow.
Gas density calibration is also important. Compare the meter
We have seen a paint manufacturer in Southeast Asia solve a repeat batch error by redoing the live zero on a Coriolis meter. They did the zero when the downstream valve was still open. The manual said close the valve first. After a proper zero, the batch weight improved by 1.8 percent. Most engineers forget that a small flow, even 0.1 kg/h, can ruin the zero point.
Manual Alerts and Common Field Mistakes
The calibration manuals often warn against zeroing a Coriolis meter with two phase gas. Gas and liquid mixed in the measuring tube creates a random drive gain. If the drive gain is unstable, the density and flow values will also be unstable. Clear the line and dry it before zeroing. The same warning applies to thermal meters with condensation on the sensor. Water droplets change the heat transfer and the meter reads incorrectly.
Warm up time is another point. Thermal meters need 15 to 30 minutes before the sensor temperature stabilizes. Coriolis electronics need about 5 minutes. Set the damping to a value that removes pump pulsation but does not hide real flow changes. For gas flow, a damping of 2 to 5 seconds is typical. Longer damping can mask a process leak or a valve problem.
How Silver Instruments Supports Gas Mass Flow Calibration
Silver Automation Instruments supplies thermal mass flow meters and Coriolis mass flow meters for gas and liquid service. We do not publish Yokogawa manuals but we follow similar calibration logic on our devices and we can support projects that use Yokogawa meters. We supply replacement spares, signal converters, and calibration setup advice. Send us your gas composition, pressure bar, temperature °C, pipe size DN, and flow range kg/h. We will confirm a meter model and price for your application.
Contact Silver Instruments: Tel: +86-25-68650347 | WhatsApp: +86-25-52155837 | WeChat: +86 15365082610
What gas types are covered in Yokogawa thermal mass flow calibration manuals?
Air, nitrogen, oxygen, carbon dioxide, argon, methane, natural gas, and biogas are common. Some manuals include mixed gas curves. Always confirm the exact gas code in the transmitter before you start the process.
How often should a gas mass flow meter be recalibrated?
For custody transfer or batch charging, verify zero and span every 12 months. For process monitoring, every 18 to 24 months is common. If the gas composition changes, verify density and flow factor immediately.
Can a Coriolis meter be zeroed with gas at line pressure?
Yes. The Yokogawa manual typically requires process pressure and a completely stopped flow. Close the downstream valve. Wait for stable temperature. Then run the zero procedure from the local display or HART.
What is the typical accuracy of a Yokogawa Coriolis gas mass flow meter?
Most models state liquid accuracy of ±0.1 percent of rate. Gas accuracy is often ±0.5 percent of rate depending on density and pressure. Always check the calibration sheet for the actual gas and test conditions.
What information does Silver Instruments need to quote a gas mass flow meter?
We need gas type, pressure bar, temperature °C, pipe size DN, flow range kg/h, and signal type. For hazardous areas, also send the zone classification such as ATEX Zone 1 or Zone 2.