In the dry rotary vacuum pump, there is a structure of the power part of the dry rotary vacuum pump, i.e. the closed motor, which is used by the device where the reaction generated gas is difficult to flow into the semiconductor manufacturing device as it flows through the reaction generated gas.
In the semiconductor manufacturing process, the problem is to contaminate the semiconductor by mixing impurities such as oil in the reaction chamber. In particular, the mixing of oil from the vacuum pump used to discharge the gas in the reaction chamber becomes a problem. Therefore, rotary dry vacuum pump has been used. As a rotary dry vacuum pump, there are screw type, roots type, scroll type and so on. However, such a rotary dry vacuum pump has a rotating shaft for rotating the rotor, and a bearing is used to support the rotating shaft. In order to prevent the oil molecules of the lubricating oil from entering the exhaust chamber of the rotary dry vacuum pump, a shaft seal is arranged between the exhaust chamber and the bearing part. However, when the shaft seal is worn, there will be leakage through the shaft seal from the exhaust chamber of the rotary dry vacuum pump to the reaction chamber. This is because the motor used to rotate the rotor is in the atmosphere, and the pressure difference between the motor side and the vacuum exhaust chamber side is large. Therefore, in the case of shaft seal clearance due to wear, the air will leak into the exhaust chamber, which is also the main reason to reduce the performance of the pump. Therefore, in the rotary dry vacuum pump with a rotary driving part, a closed type motor which can make the madane also become the same pressure as the exhaust chamber is adopted. The structure of the enclosed motor is as follows: the stator winding with a rotating magnetic field generated in the stator core is used to seal the diaphragm with a frame, a side plate and a metal thin-walled cylinder diaphragm (cavity) installed on the inner diameter side of the stator, and the rotor is installed on the rotating shaft supported by the bearing fixed on the bracket and rotates freely.
Dry rotary vacuum pump main features
The lower end of the rotor is removed, and the rotor is rotated once to exhaust. A sealing structure is formed between the rotor and the internal surface of the pump, with less leakage of the rectangular section clearance. Therefore, a higher compression ratio can be obtained. The compression ratio and pumping speed of the pump are related to the leading angle of the rotor, the clearance between the rotor and the pump body, the engagement rate, the number of turns, the diameter of the rotor and the rotation speed.
Because of its large number of turns, higher compression ratio than the screw type mentioned above, and low pumping speed, the pump can be pumped from atmospheric pressure to the limit pressure of 10-1pa, and the pump with pumping speed of 40-80m3 / h is commercially available.
The larger the rotation angle of the plunger to the non oil supply position is, the greater the distance from the upper end face of the plunger to the beveled edge of the oil return hole of the opening plunger sleeve is, and the larger the oil supply quantity is. If the rotation angle of the plunger is smaller, the oil cut-off starts earlier and the oil supply quantity is smaller. When the diesel engine stops, the oil must be cut off. Therefore, turn the longitudinal groove on the plunger to the oil return hole on the plunger sleeve. At this time, in the whole plunger stroke, the fuel in the plunger sleeve always flows back to the oil passage through the longitudinal groove and the oil return hole, there is no oil pressure process, so the oil supply is equal to zero. When the plunger rotates, the fuel supply is adjusted by changing the end point of the fuel supply.
The method of adjusting oil quantity of dry rotary vacuum pump is introduced in this paper. To use a product, it is necessary to have a clear understanding of the product knowledge before it can be better used. Therefore, it is necessary for operators and factory applications to understand all aspects of the technology and operation methods of the product.
In dry rotary vacuum pumps, suction valves and exhaust valves are very important parts and are vulnerable parts. Their work directly affects the ultimate pressure, pumping speed, power consumption and reliability of reciprocating pumps.