Steps of test pumping of imported vacuum pump

Any imported vacuum pump to be repaired, repaired pump or a new pump shall be tested to see if there is any fault, the form and position of the fault, the limit vacuum degree that can be reached and the time of experience If there is any condition, the pumping rate shall be identified The specific methods and steps of test pumping are as follows: 1 Clean all parts of the pump to remove oil and dirt Remove the belt, and use the reverse switch to test the positive and negative rotation of the motor, so that its rotation direction is consistent with the arrow direction marked by the pump wheel If there is no mark on the pump wheel, press the air inlet of the pump with your palm, and turn the pulley with the other hand When you feel that there is suction inward, the rotation direction of the pulley is the correct direction, and make a mark Then install the belt Connect the test device at the air inlet of the pump before starting the pump Usually, one end of the vacuum rubber tube is inserted into a thermocouple gauge tube, and the other end is inserted into the air inlet of the pump to be tested Before this, a little castor oil should be applied on the rubber pipe mouth to make it lubricated and easy to plug The rubber pipe is clamped with an iron clip (if it is connected with a metal pipe, it is connected with a flange at the pump port, and the other end is sealed with a metal glass to connect with a gauge pipe or with a gauge pipe joint, and there is a vent valve in the middle of the pipe) First, turn the pulley by hand for several turns If there is no big obstacle, the motor can be started intermittently Run the pump properly 2 Check the operation of the vacuum pump: listen to the noise and abnormal sound of the pump; see how the valve plate of the air port is bouncing; check whether the oil reaches the oil standard center, whether there is oil leakage, air leakage and water leakage; check whether the surface of the pump cavity is deformed, etc make records one by one 3 Check the change of the vacuum degree with high-frequency spark leak detector and thermocouple vacuum gauge The spark is hit on the neck of the gauge tube (not on the gauge tube), and the vacuum degree can be judged by the glow color; normally, the glow color will gradually change from dark purple and rose red to light blue after the pump is turned on, until the glow is very tiny, only the fluorescence of the glass is seen, at this time, the vacuum degree has been higher After the glow changes to light blue, the thermocouple vacuum gauge can be used to monitor the vacuum degree At the beginning, it can also be measured by thermocouple vacuum gauge alone However, the two should not be carried out at the same time to avoid damage to the thermocouple gauge If the spark detector is used to move back and forth on the glass tube during the inspection, and the glow cannot be produced, and the spark can drill into the glass tube to form a linear shape, it indicates that the vacuum degree is very low (close to atmospheric pressure) If it is always purple, and the vacuum degree of the pump is not high, check all parts of the pump carefully to see if there is air leakage at the rubber pipe joint, etc If the thermocouple gauge has certain indication when measuring the vacuum degree, it can clamp the iron clamp or stop the pump suddenly for a short time to record the pressure change curve with time, and judge whether the pump is bad or caused by air leakage It is necessary to carefully distinguish the different conditions of three curves of air leakage, air release and pump damage, and make careful judgment When using thermocouple vacuum timing, pay attention to its test characteristics The vacuum degree it measures is the total pressure of gas including water and oil vapor The reading is related to the type of gas For the identification of imported vacuum pump, it is required to measure the partial pressure of gas with a compressed vacuum gauge, which has nothing to do with the type of gas If the pump does not record the original data, it can be generally considered that it should be repaired if it is less than 50 grids Naturally, whether the vacuum pump needs to be repaired mainly depends on the actual production needs and possible conditions.