Comprehensive understanding of the vacuum coating machine, coating machine structure in detail (II)
(Continued from the previous issue)
Mechanical pump exhaust effect is also related to the motor’s speed and belt tightness, when the motor’s belt is relatively loose, the motor speed is very slow, the mechanical pump exhaust effect will be worse, so it is necessary to frequently maintain, check, mechanical pump oil sealing effect also need to be often check, oil is too little, can not achieve the sealing effect, the pump will leak, oil is too much, the suction hole is clogged, can not suction and exhaust, in general, in oil level Generally, the oil level is 0.5 centimeters below the line.
Booster pump is also called Roots pump: it is a mechanical pump with a pair of synchronized high-speed rotation of double lobe-shaped or multi-lobe-shaped rotor, because of its working principle is the same as the Roots blower, so it can also be called the Roots vacuum pump, this pump has a large pumping speed within the range of 100-1 Pa pressure, which makes up for the shortcomings of the mechanical pump in this range of exhaust capacity is insufficient, this pump can not start working from the atmosphere, and can not be directly discharged from the Atmosphere, its role is only to increase the pressure difference between the inlet and exhaust ports, the rest is required to complete the mechanical pump, so it must be equipped with a mechanical pump as a pre-stage pump.
Mechanical pumps must pay attention to the following issues in the process of use:
 The mechanical pump should be installed in a clean and dry place.
 The pump itself should be kept clean and dry. The oil in the pump has a sealing and lubricating effect, so it should be added according to the specified amount.
 The pump oil should be changed regularly, and the previous waste oil should be drained out first, and the period should be at least three months to half a year.
 Connect the wires according to the instructions.
 Before the mechanical pump stops working, close the air inlet valve, then stop the power and open the air valve, and put the atmosphere into the pump through the air inlet.
 The oil temperature should not exceed 75 degrees Celsius while the pump is in operation, otherwise the sealing will not be tight due to the low viscosity of the oil.
 From time to time, check the belt tightness of the mechanical pump, the rotational speed of the motor, the rotational speed of the Roots pump motor, and the sealing effect of the sealing ring.
