The vacuum pumps need matters needing attention:
1. The vacuum pump working pressure should satisfy the vacuum equipment vacuum and pressure requirements.Such as: vacuum coating requirements of 1 × 10-5mmHg vacuum degree, the vacuum pump vacuum degree and at least 5 × 10-6mmHg.Often choose to pump vacuum degree of vacuum equipment vacuum degree higher than one half to one order of magnitude.
2. To correctly select the vacuum pump working point.Each pump has certain working pressure range, such as: diffusion pump for 10-3~10-7mmHg, in such a wide pressure range, the pumping speed as the pressure changes, its stable working pressure range of 5 × 10-4~5 × 10-6mmHg.Thus, the working point of the pump should be selected in this range, and can't make it in the 10-8mmHg under a long-term work.And as the titanium sublimation pump can work under the 10-2mmHg, but its working pressure should be less than 1 × 10-5mmHg as well.
3. Vacuum pump in the working pressure, should be able to discharge vacuum equipment process generated by all the gas volume.
4. The right combination of vacuum pump.Because the vacuum pump is selectively pumping gas, therefore, sometimes using a pump can not meet the requirements of pumping gas, need several pump combination, complement each other in order to meet the requirements of pumping gas.Such as titanium sublimation pump on hydrogen with high pumping speed, but does not draw a helium, and the triode sputtering ion pump, (or bipolar type asymmetric cathode sputter ion pump) on argon has a certain speed, the two together, can make the vacuum device to get a better degree of vacuum.In addition, some vacuum pump can work in pressure, the need for vacuum; some vacuum pump outlet pressure below atmospheric pressure, need to pump before, they need to pump used in combination.
5. Vacuum equipment for oil pollution requirements.If the equipment in strict requirements without oil, should choose all kinds of pumps, such as: water ring pump, molecular sieve adsorption pump, sputter ion pump, cryogenic pump.If the requirements are not strict, can choose to have the fuel pump, plus some oil pollution prevention measures, such as adding cold trap, baffle, oil well, also can achieve the clean vacuum.
6. Understand the pumped gas composition, gas containing excluding condensable vapor, there is no dust particles, has no corrosion.Selection of vacuum pump, need to know the gas composition, the choice of the corresponding pump was pumping gas.If the gas containing steam, particles, and corrosive gas, should be considered in the pump inlet pipe on the installation of auxiliary equipment, such as condenser, dust collector.
7. Vacuum pump oil vapor is discharged to the environment influence how.If environmental pollution is not permitted, can choose oil-free vacuum pump, or the oil vapor is exhausted to outdoor.
8. When the vacuum pump works produced by vibration on the process and environment has no effect.If the process is not allowed, should choose no vibration of the pump or the taking of anti vibration measures.
9. Vacuum pump prices, operation and repair costs.