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2022-07-23 13:34:31
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Today is the hottest time of the year! But do you know how the hottest weather will affect the micro differential pressure gauge? In view of the common problems of the verification procedures of the micro-differential pressure gauge, the editor will analyze the data for you here:
Micro differential pressure gauges are widely used in pharmaceutical factories and microelectronics factories to measure environmental micro differential pressures. The pointer indicates the pressure value faster. However, the micro differential pressure gauge is a special pressure gauge, which is used to measure the difference between two pressures, and the measured differential pressure value is very small, and there will be relatively common problems. The following is an analysis of these common problems.
1. The standard device cannot be completely covered
At present, the commonly used standard instruments for calibrating micro differential pressure gauges are compensating micro pressure gauges and digital pressure gauges. Some ranges of micro differential pressure gauges are 0~30Pa and the accuracy level is 4, then the allowable error is ±1.2Pa. According to the verification regulations, the allowable error of the standard table is not greater than one-fourth of the allowable error of the tested table, so the verification is 0 The standard tolerance of the ~30Pa micro-pressure gauge should not be greater than ±0.3Pa, while the tolerance of the first-class compensation micro-pressure gauge is ±0.4Pa. The digital pressure gauge for measuring micro-pressure has high requirements on the sensor, and some digital pressure The minimum tolerance of the gauge can only be ±0.5Pa. The verification regulations stipulate that if a digital pressure gauge is used as a standard device, it must be above 0.05 level and the annual stability is qualified, so it is difficult for the compensation type micro pressure gauge and digital pressure gauge to be used as the standard device. Covers all ranges of micro differential pressure gauges. For the range that cannot be covered, it cannot be judged whether it is qualified or not during the verification, and a verification certificate cannot be issued. Only a calibration certificate and uncertainty can be issued for customers' reference.
2. Static pressure zero error measurement of micro differential pressure gauge
The micro differential pressure gauge is used to measure the difference between two pressures. There are high pressure and low pressure ports, and there is a static pressure influence. The static pressure zero error should be measured, and there is no requirement for the measurement of the static pressure zero error. When the static pressure zero error of measuring the differential pressure gauge is large, it may cause a large error in the differential pressure value measured by the gauge during operation. If it exceeds the allowable error range, the differential pressure gauge cannot be judged. qualified. Therefore, it is suggested that the static pressure zero position error should be measured when calibrating the micro differential pressure gauge, and the verification certificate should be issued with caution when the static pressure zero position error is large. Static pressure zero error measurement method: connect the high pressure end and the low pressure end of the micro differential pressure gauge to the pressure generator through a three-way pipe, generate the rated static pressure through the pressure generator, and then read the change of the zero position of the gauge under test.
The experimental results show that the static pressure zero error of the micro differential pressure gauge is within the tolerance range. If the static pressure zero error is greater than the maximum allowable error, it is recommended to issue a calibration certificate and inform the customer that the static pressure zero error is too large.
3. Measurement of pressure stabilization time of micro differential pressure gauge
When applying pressure to the micro differential pressure gauge during the verification process, it is found that although the deflection of the individual gauge pointer is stable, the pointer deflection is relatively slow, and the lag occurs, which may be caused by a problem with the mechanical structure of the micro differential pressure gauge, which leads to poor sensitivity. . If the micro differential pressure gauge has a long lag time, it cannot display the measured differential pressure value in time, which may have a certain impact on the use of the enterprise. However, the verification regulations do not require the time for pressure stabilization, so it is suggested that the time required for pressure stabilization can be measured when calibrating the differential pressure gauge. Micro differential pressure gauge voltage stabilization time measurement method: apply the upper limit pressure of the micro differential pressure gauge measurement range, and measure the time from when the pressure of the standard device is stable to the time when the pressure of the tested gauge is stable. From the usual verification, it is found that the voltage stabilization time of the micro differential pressure meter is within 5s. When the voltage stabilization time of the micro differential pressure meter is more than 10s, the verification certificate should be issued with caution. It is recommended to issue a calibration certificate and inform the customer that the voltage stabilization time is too long.
Well, the above content is what Xiaobian thinks to remember. If you have other ideas or suggestions, please feel free to call Weihai Kunke Flow Meter Co., Ltd., or you can log in to the company's official website for more information. (www.kunkeandao.com/en) We also have a 24-hour customer service online, ready to help you solve practical problems at any time. Remember to pay attention to the editor, the next issue will be more exciting.
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