Using differential pressure sensor and select six characteristics of attention

Differential pressure sensor is usually used to test bench, wind tunnel, the leak detection system and other applications. This article mainly explains the selecting for differential pressure, in critical pressure sensor of application, the need to pay attention to the six characteristics and considerations. A, incorrect installation direction effect, vibration, system maintenance and even leads to the differential pressure sensor position change, this is called the direction effect. For a long time, direction effect for other types of sensing technology is a problem. Even the correct installation of sensors will have the edge effect of gravity, because sensors rotate 180 degrees from the positive gravity into a negative gravity, thus the change of the stress of the 2 g. In this case, the sensor can't will exert gravity force and the force applied by pressure port. As a result, the sensor will be weighted influence combined with port pressure, gravity and send the wrong signal. To populate the silicone oil or other isolation medium of sensors, sensor rotates in the direction of the effect will be more obvious. The sensor diaphragm weight and the weight of the filling liquid will affect differential pressure sensor. Also, the sensor can't detect the real pressure, will send with azimuth change of the error value. Second, the vibration from nearby motor or fan of low frequency vibration will affect correct positioning of the sensor. Oil gas sensor, for example, may pick up the liquids in the low frequency vibration, and an inertial load, are added to the diaphragm pressure changes will be mistaken for a process. In order to avoid this kind of vibration effect, end users need to install the sensor in the distant quiet area. Similarly, if the reference with the atmosphere in port and it needs to connect to an area without vibration noise and wind. For wind tunnel, due to the installation of a pitot tube, so the two pressure ports can be fixed by tube or a hose connection to the remote installation of sensors, so as to prevent the air disturbance noise or mechanical vibrations are transmitted to the sensor. Third, overvoltage protection of overvoltage protection and reverse pressure differential pressure sensor protection has been a leak detection system manufacturer attaches great importance to the problem. These systems for applications in high differential pressure and static pressure of small leakage rate. Leak detection manufacturers are always hoping that measurement is more and more low leakage rate. Due to the leakage rate is proportional to the differential pressure directly, the manufacturers hope to be able to more and more small differential pressure measurement. To achieve this goal, needs to be increased to higher static test pressure. Four, line pressure effects besides overvoltage, also need to consider the change of the line pressure, especially in high static line pressure leak detection applications. Line pressure is applied to the sensor on the port pressure. Static line pressure, however, some changes may cause the sensor on the deformation and stress of the slight shape. The stress response, in turn, will change the sensor calibration, affect the sensor's zero point and range. A new generation of sensor design can significantly reduce the static pressure on strain sensing element. Search for a sensor with a rated low pressure effect. Five, the response time difference pressure sensor response time is another important factor, especially for the pressure control and wind tunnel applications. The response time of the sensor, Pressure on the sensor from the response of a, the time interval to produce the output signal) Mainly by the sensor sensing element and the adopted technology of the electronic components. Using capacitance diaphragm usually response of the sensor technology is very fast. Them through the sensor to detect and measure the pressure change at the ends of the capacitor voltage, the capacitor of a plate diaphragm pressure is able to reflect the minor changes. Capacitance changes can be caused by the sensor of the electronic component is detected, the electronic components after linearization, thermal compensation, modulation, output is proportional to the high level signals. Differential pressure sensor to the demand of the rapid response time depends on the application. Wind tunnel for example, in the measurement of dynamic air velocity change applications, the sensor output signal with the change of wind speed, therefore need a quick response time. For the majority of test rig, leak detection and application of wind tunnel, 10 - The response time of the 80 mm is generally acceptable. For the response time is less important normal processing and monitoring applications, response time is usually for several seconds, rather than the number of milliseconds. In the design of system, understanding the response time requirements of the pressure sensor is very important, is not always the sooner the better. If the sensor response speed is too fast, sometimes rapid sensor response short not filtering and without noise or turbulence of system pressure fluctuations. In this case, the filter output signal attenuation off these unwanted interference.