How to choose vacuum unit in architectural coating industry? How to choose a good vacuum pump unit?
When one kind of pump can not meet the requirements of air extraction and vacuum, several pumps need to be combined to supplement each other to meet the process requirements. Some vacuum pumps can not work under atmospheric pressure and need pre vacuum; some vacuum pumps with outlet pressure lower than atmospheric pressure need front stage pumps, so they need to be combined. The combined vacuum pump is called vacuum pump unit. It can make the vacuum system get better vacuum degree and air displacement. We should choose the combined vacuum pump correctly, because different vacuum pumps have different requirements for the gas to be removed.
When you choose an oil sealed pump, you should first know whether your vacuum system has requirements for oil contamination. If the equipment is strictly required to be oil-free, all kinds of oil-free pumps should be selected;
It is necessary to know the composition of the extracted gas, whether there is condensable steam in the gas, whether there is particulate dust, whether there is corrosiveness, etc. When selecting a vacuum pump, it is necessary to know the composition of the gas and select the corresponding pump for the selected gas. If the gas contains steam, particles and corrosive gases, auxiliary devices such as condensers and dust remover should be installed on the intake pipe of the pump. When selecting oil sealed vacuum pump unit, the influence of oil vapor discharged from vacuum pump on environment should be considered.
Precautions for use of vacuum unit:
1. Unpack and rotate the coupling between the pump and the motor in the direction of the arrow;
2. Open the oil filling plug on the top of the vacuum pump oil tank and pour the vacuum pump oil into the pump. The oil level should be between half and two thirds of the visible part of the oil indicator. If the oil level is too high, fuel injection will occur. If the oil level is too low, the vacuum will be affected, and the temperature will rise and the noise will be increased, which will affect the performance of the pump. No. 1 vacuum pump oil is selected as pump oil;
3. Open the black rubber cover on the air inlet and exhaust port, add a small amount (1 teaspoon) of vacuum pump oil from the air inlet to facilitate start-up. Connect the vacuum pump and the vacuum system (the air inlet of the vacuum pump is lower than the air outlet of the instrument to be pumped). The pipe connecting the instrument to the vacuum pump should not be too long.
The diameter of the connecting pipe should not be smaller than the inner diameter of the air inlet of the vacuum pump, otherwise the pumping speed will be affected, but smaller than the outer diameter of the air inlet, otherwise the sealing degree will be affected. Pumping volume can not be too large, generally will choose the pump speed in seconds 15-20 times. Apply vacuum grease to the movable joint to enhance its sealing degree;
4. When connecting the power supply and wiring, pay attention to the wiring requirements on the motor name plate;
5. Three phase motor should pay attention to the motor rotation direction should be consistent with the direction of the arrow on the pump bracket. Or before connecting the pipeline, first connect the wire for trial run, and then block the air inlet by hand to see whether there is suction. If there is suction, the wiring is correct. Otherwise, the direction of rotation can be changed by changing any two wires (Note: when determining the direction of rotation for three-phase motor, it should be carried out instantaneously);