The use of water ring vacuum pumps is already a very common type of equipment. How do we test the pumping rate of water ring vacuum pumps during normal use?
(1) Water ring type vacuum pump with voltage regulator: The rotor type wire of this vacuum pump adopts arc type, which adopts involute type, and also adopts combination line type, which has been described in detail above. Again, the difference between this pump and the dry vacuum pump is that the front pump can be used to directly discharge the atmosphere without air cooling, but it is cooled by water. A pressure regulating box is installed on the air outlet of the pump casing, which can stabilize the sound. The effect of pressure is very convenient to use.
(2) Water ring vacuum pump with separator and muffler in direct air: The structure, working principle and rotor profile of this vacuum pump are exactly the same as those discussed above. It is also a kind of water cooling with a foreline pump. The so-called wet water ring vacuum pump that discharges the atmosphere; the only difference is that there is no surge tank on the air outlet, but a gas water separator is installed on the pipeline of the air inlet, and the pipeline is installed on the air outlet. Separation and muffler to play the role of gas-water separation and noise reduction.
The pumping rate of the water ring vacuum pump is determined by the constant pressure method. The test hood is directly connected at the inlet of the pump. The outlet of the pump is connected with the mechanical pump of the front stage oil seal. The vacuum gauge is used to measure the pressure at the inlet and the outlet. The adjustable needle valve is in communication with the test cover. Measurements can only be taken after the vacuum pump has been started and stable conditions have been reached. The pumping rate is measured from the appropriate value close to the ultimate vacuum, and is measured until the pump's allowable inlet pressure is near. Four points are measured in each order of magnitude, and the distribution should basically match the ratio of 1, 2, 5, 7, for example 1xl0-2, 2x10-2, 5x10-2 and 7xl0-2 four points, in the measurement process, each time the needle valve is adjusted to reach a certain pressure, at least after 3 minutes, the pressure reading on the vacuum gauge is stable, and the pressure data can be recorded. . If the pressure changes, the average value of the pressure during the measurement should be used.
The structural dimensions of the test hood are specified in the ministerial standard (JB1875-73), and the inner diameter D of the test hood should be equal to the inlet diameter of the pump.
In the device for measuring the pumping rate of the water ring vacuum pump, the vacuum gauge used shall be a seat type compression vacuum gauge and an oil U-type vacuum gauge, and calibrated by a compression type vacuum gauge with an accuracy of 10% or more, the air intake port plane of the vacuum gauge. It should be parallel to the direction of the airflow. The flow meter used for the flow side quantity must have secondary accuracy within the measurement range.
