The exhaust manifold is one of the parts of the automobile engine, and its performance has air tightness requirements, because if the exhaust manifold leaks, then it will affect the engine, such as the engine's power performance, emission performance and the noise of the whole machine; therefore, the exhaust manifold needs to be fullySuitable for engine high temperature and high pressure sealing conditions. 

With the advancement of the times and the development of testing technology, traditional engine exhaust manifold air tightness testing has---Soaking method and smearing method are both availableWas eliminated.In order to improve detection efficiency and accuracy, Hirays Automation Technology Co., Ltd. has developed a popularAir tightnessDetectorThe working principle of air tightness detection using the differential pressure method is in line with the need for intelligent detection of air tightness of parts during mass production on the production line.

SoDifferential pressure method air tightness testingWhat is your job like??In fact, it is calculated by measuring the change of pressure in the container using the gas flow formula.There are four processes for detecting leakage:

（1）Inflation process: Set the system pressure to the test pressure, then open the inflation valve and leak detection valve, and fill the standard container and the workpiece under test with the required pressure.The compressed air force is equal to the test pressure. Due to the influence of gas flow, the internal pressure and temperature of the system will fluctuate at this time, and it must be continuously inflated.Until the standard container and the workpiece to be tested are fully inflated.

（2）Balancing process: close the inflation valve and leak detection valve, and cut off the passage between the gas source, the standard container, and the workpiece to be tested. Due to the inflating and closing valves,The action will cause the pulsation of the gas pressure in the container, causing the differential pressure between the standard container and the workpiece to be measured to be unstable and show irregular changes.It is necessary to delay for a period of time until the differential pressure value stabilizes before measuring the differential pressure change.

（3）Detection process: Detect the output of the differential pressure sensor. The pressure drop due to leakage is approximately proportional to time near the test pressure.，Therefore, the change in differential pressure within a certain period of time can be measured.

（4）Exhaust process: After measuring the change value of the differential pressure, the remaining gas in the standard container and the workpiece to be measured is exhausted to the atmosphere through the air valve, endingA detection process.