Addtime： 2020-07-18 Browse times： 2953
Vacuum pump has selective pumping, so sometimes one kind of pump can't meet the requirement of air pumping. It needs several kinds of pumps to combine and supplement each other to meet the pumping requirements. If the titanium sublimation pump has a high pumping speed for hydrogen, but can not pump helium, and the tripolar sputtering ion pump (or bipolar asymmetric cathode sputtering ion pump) has a certain pumping speed for argon, the combination of the two will make the vacuum device get better vacuum degree.
Causes of high temperature: low fan speed, low air pressure and small air volume. The motor has high power, high working current and high heat output. The number of fan blades is less and the air volume is small. The bus voltage of the vacuum pump motor is 380V. Due to the cable voltage drop and uneven load distribution, the actual voltage applied by the motor is only 365v. The low voltage results in large operating current. Motor with dust, oil, reduce the heat dissipation capacity.
Solution: motor power, speed and vacuum pump matching, can not be changed. The fan is installed on the main shaft of the motor. The speed of the motor determines the speed of the fan and cannot be replaced. Although increasing the number of fan blades can play a certain role, but the dynamic balance is not easy to find after the number of blades is increased. If the alignment is not good, the motor vibration will increase. The original fan cover was lengthened by 40cm, and an axial flow fan with the same diameter as the fan cover was installed. The motor power of the axial fan was 850W, the speed was 1489r / min, and the voltage was 380V. The original fan remains. The axial fan clothing school has another power supply control, and the axial fan and the main motor are not interlocked. After the vacuum pump is started, the axial flow fan shall be started in time, and the axial flow fan shall be stopped 30 minutes after the vacuum pump is stopped to fully cool the main motor; the dust on the motor shall be removed regularly to keep the heat sink of the motor clean to increase its heat dissipation capacity; the bus voltage of the vacuum pump shall be adjusted to 400V.
In order to prevent the vacuum pump oil from returning to the pumped container when the pump is stopped, it is very important to have a built-in anti oil return device. The prevention of oil return after pump stop usually depends on the combination of gas circuit and oil circuit
A pump stop and oil return prevention device is set on the air inlet channel.
The oil return control device is arranged on the oil return circuit.
Principle of vacuum pump anti return valve: reliable anti return oil device at air inlet, double protection, no oil return, ensuring the safety of vacuum system.
Protection 1: when the pump stops, the isolation valve closes the vacuum system;
Protection two: shut off the oil circuit and inflate the pump chamber when stopping the pump.
During the operation of the vacuum pump, the control piston keeps sealing against the spring under the action of oil pressure. The disc of the anti reverse suction valve is kept in a low position (valve open) due to its own weight. After the pump stops, the oil pressure drops and the spring pushes the piston upward. This creates a path between the tank and the piston of the anti reverse suction valve. The above is the principle of vacuum pump anti return valve. Compared with the vacuum pump with spring to control anti return valve, Laibao vacuum pump has better anti return oil effect, lower failure rate and simpler maintenance.
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