Vacuum pump selection method and calculation formula
The role of the vacuum pump is to extract gas molecules from the vacuum chamber, reducing the gas pressure in the vacuum chamber, to achieve the required degree of vacuum. Broadly speaking, there is a wide range of atmospheres to very high vacuum, and so far no vacuum system has been able to cover this range. Therefore, in order to meet the technical requirements of different products, work efficiency and equipment working life requirements, different vacuum sections need to choose different vacuum system configurations. For optimum configuration, the following points should be considered when choosing a vacuum system:
1, to determine the working vacuum range:
First, the vacuum required to determine each process must be checked. Because each process has its own range of vacuum degree of adaptation, we must carefully study to determine.
2, to determine the ultimate vacuum Check the vacuum level of the vacuum pump system based on the vacuum requirements of the process, because the system of the ultimate vacuum determines the system of the best working vacuum. In general, the ultimate vacuum of the system is 20% lower than the working vacuum of the system and 50% lower than the ultimate vacuum of the foreline pump.
3, the type of gas being drawn and check the exhaust gas extraction process to determine the type and amount of extraction. This is because if the type of gas being pumped reacts with the liquid in the pump, the pump system will be contaminated. At the same time must consider determining the appropriate exhaust time and exhaust gas generated during the process.
4, the vacuum volume check to determine the time required to reach the required degree of vacuum, vacuum pipe flow resistance and leakage.
Consider to achieve the requirements of the vacuum degree of vacuum in a certain process conditions required to maintain the vacuum pumping rate.
5, vacuum pump formula S = 2.303V / tLog (P1 / P2)
among them:
S is the vacuum pump suction rate (L / s)
V is the volume of the vacuum chamber (L)
t is the time required to reach the required degree of vacuum (s)
P1 is the initial degree of vacuum (Torr)
P2 is the required degree of vacuum (Torr)
E.g:
V = 500L
t = 30s
P1 = 760 Torr
P2 = 50 Torr
Then: S = 2.303V / t Log (P1 / P2) = 2.303x500 / 30xLog (760/50) = 35.4L / s
Of course, the above formula is only the theoretical calculation, there are a number of variables are not taken into account, such as pipeline flow resistance, leakage, flow resistance of the filter, was pumping gas temperature. In fact, the safety factor should also be taken into account.
Keyword Search: More Pump Product Information
Nantong Tobel Intelligent Controlling Equipment CO;LTD , https://www.tobel-tech.com