The electronic soap film flowmeter is a commonly used instrument for measuring gas flow, particularly suitable for low flow measurements. Its working principle is based on the flow of gas through a layer of soap film, and the rupture time of the film is proportional to the flow rate. To ensure the accuracy of the electronic soap film flowmeter, regular calibration is required. The verification device usually includes the following key parts:
1. Standard gas source
A standard gas source is used to provide a known flow rate of gas, which is typically a calibrated gas flow meter. The precision requirements for standard gas sources are high, and mass flow meters (MFM) or volumetric flow meters are usually used as reference for gas flow rates.
2. Verify the pipeline system
The calibration pipeline system includes pipelines connecting standard gas sources, electronic soap film flow meters, and exhaust systems. The pipeline should ensure stable flow and no leakage. During the calibration process, the flow rate must be kept constant, so the diameter, length, and material of the pipeline also have an impact on the calibration accuracy of the flowmeter.
3. Gas temperature and pressure measuring instruments
The temperature and pressure of gas are key factors affecting gas flow rate, therefore real-time monitoring of gas temperature and pressure is required during the calibration process. Common temperature sensors include RTD (resistance temperature detector), and pressure sensors can be either piezoresistive or piezoelectric.
4. Timing device
The electronic soap film flowmeter calculates the flow rate based on the time of film rupture, thus requiring a high-precision timing device. Typically, a digital timer or timing circuit is used to accurately record the time of film rupture.
5. Flow calculation device
Calculate the gas flow rate based on the known relationship between membrane rupture time and flow rate. This part is usually calculated in real-time through an electronic control unit (ECU) or microprocessor, and the flow rate is automatically displayed.
6. Calibration and adjustment of equipment
In order to ensure that the calibration device of the electronic soap film flowmeter is in good working condition, calibration and adjustment may be necessary. For example, checking the accuracy of membrane rupture and the stability of gas flow rate.
7. Data recording and analysis system
Modern calibration devices are usually equipped with computer systems that can record various data during the calibration process in real time, including flow rate, time, temperature, pressure, etc., and perform data analysis for accuracy calibration and adjustment.
Overview of the Verification Process:
Connect the electronic soap film flowmeter to the standard gas source and calibration pipeline system.
Adjust the standard gas source flow rate to achieve the desired flow value.
Record the time of membrane rupture through a timing device.
Calculate the flow rate based on the rupture time and known relationship.
Compare the calculated flow rate with the standard flow rate and check the error of the electronic soap film flowmeter.
Adjust according to the error to ensure the accuracy of the flowmeter.
Through this verification method, the accuracy of the electronic soap film flowmeter can be ensured to meet the application requirements.