Key points of vacuum pump selection and use

The effect of vacuum pump is pumping gas molecules from the vacuum chamber, reduce the gas pressure of vacuum chamber, make it meet the requirements of vacuum degree.Generally speaking from the atmosphere to the extremely high vacuum has a large range, so far has not been a vacuum system can cover the scope.Therefore, in order to reach the technical index of different products, the efficiency and the working life of the equipment requirements, different vacuum sections need to choose a different vacuum system configuration.To achieve the best configuration, select the vacuum system, all point should consider the following:

1, determine the scope of the work of vacuum
You must check to make sure the vacuum degree of each technical requirement.Because each kind of technology has its adaptive scope of vacuum degree, must be determined carefully study.

2, determine the ultimate vacuum
On the basis of the determined the technological requirements of vacuum check limiting vacuum of vacuum pump system, because the system of the ultimate vacuum decided the best job in the vacuum of the system.System, in general, the limit of the vacuum system of vacuum degree of work that are lower than 20%, 50% lower than the ultimate vacuum pump before.

3, is pumped gas species, and swept volume
Check to make sure the process requirement types and swept volume of extraction.Because if the smoke gas species react with liquid in the pump, pump system will be contaminated.At the same time must consider the exhaust time and determine appropriate extraction process of gas volume.

4, vacuum volume
Check to make sure the time required to meet the requirements of vacuum, vacuum pipe flow resistance and leakage.Consider meet the requirements after vacuum needs in the conditions of process requirement, to maintain the vacuum extraction rate.

5, vacuum pump calculation formula

S = 2.303 V/tLog (P1 / P2)

Among them:
S for the vacuum pump suction rate (L/S)
V is for vacuum chamber volume (L)
T to reach for the vacuum degree required by the time (s)
P1 for initial vacuum (Torr)
P2 for vacuum degree (Torr)

Such as:
V = 500 l
T = 30 s
P1 = 760 torr
The P2 = 50 torr
Is: S = 2.303 V/t Log (P1 / P2) = 2.303 x500/30 xlog (760/50) = 35.4 L/S

On the type of course is just the theoretical calculation results, there are a number of variable factors not taken into account, such as pipe flow resistance, leakage, flow resistance of the filter, is pumped gas temperature, etc.In fact should also take into consideration of the factor of safety.

Vacuum pump is a kind of rotary varactor pump , which need to equipped with backing pump ,such as rotary vane vacuum pump , rotary piston vacuum pump, oil diffusion vacuum pump and so on , and then which fit for use in a wide range of pressure , with large pumping speed  , pumping gas containing dust and water vapor is not sensitive , the vacuum pump is widely used in metallurgy, chemical industry, food, electronic plating, etc.