equal pitch oil-free screw vacuum pump selection

Today, we will introduce the constant pitch oil-free screw vacuum pump which has been widely used at present, and mainly explain its structural characteristics and pumping principle. The oil-free screw vacuum pump was introduced into China’s vacuum industry in the 1990s. It is a dry-type oil-free vacuum pump. At present, this kind of pump has been widely used in high-tech industries such as chemical industry, medicine, metallurgy and electronics. It has a large share in the current vacuum pump market.

Every time the screw rotor of equal pitch oil-free screw vacuum pump stops pumping process, it can be divided into the following stages: contraction suction, equal volume transportation, adiabatic tightening and equal pressure exhaust. In each stage, the physical parameters of the extracted gas such as mass, volume, temperature, pressure, internal energy will change. And the exhaust power consumption and exhaust temperature of equal pitch oil-free screw vacuum pump change with the change of inlet pressure. The contents are as follows:

Suction stage: the gas storage volume at the front end of the two screw rotors is indirectly connected with the screw pump inlet. During the process of screw migration and transformation and backward movement of suction slot, the gas storage volume continuously shrinks and expands, and the extracted gas outside the pump enters the gas storage volume under the influence of pressure difference, and the isolated gas storage volume and the gas absorbed outside it continue to move backward and stop The process of gas delivery from the pump suction port to the pump exhaust port.

The pressure of the gas is increased from the suction pressure stage to the compression stage. At the end of the contraction stage, the total mass of gas in the gas storage space increases greatly. The pressure is the exhaust pressure, and the temperature is the mixed temperature of the two sector gases. The total energy, enthalpy and entropy are also the sum of the two sector gases.

Exhaust stage: from the gas storage space and vent connected, the exhaust process of screw pump has begun. The screw rotor does the most work on the gas, which is converted into the kinetic energy, internal energy and heat release of the exhaust gas and then dissipates in the cooling system and exhaust space of the pump.

The rotor profile of equal pitch oil-free screw has the following characteristics:

(1) Can greatly reduce a lot of planning, processing and other aspects of the workload.

(2) Complete sealing can be completed with short sealing line. This type of line also has revealed triangles, but less between stages.

(3) Reduced vibration and noise. Therefore, its dynamic balancing function is better than that of single screw rotor.

(4) Easy to process and manufacture. It can effectively ensure the pumping function of vacuum pump.