Problems to be Noted When Using a Vacuum Pump

1. The working pressure of the vacuum pump should meet the ultimate vacuum and working pressure requirements of the vacuum equipment. For example, the vacuum coating requires vacuum of 1×10-5mmHg, and the vacuum degree of the selected vacuum pump should be at least 5×10-6mmHg. The vacuum level of the pump is usually chosen to be one half to one order of magnitude higher than the vacuum level of the vacuum equipment.

2. Correctly select the working point of the vacuum pump. Each pump has a certain range of working pressure, such as: the diffusion pump is 10-3~10-7mmHg. In such a wide pressure range, the pumping speed varies with pressure, and its stable working pressure range is 5×10. -4~5×10-6mmHg. Therefore, the operating point of the pump should be selected within this range, and it cannot be allowed to work long-term at 10-8mmHg. Another example is the titanium sublimation pump can work under 10-2mmHg, but its working pressure should be less than 1 × 10-5mmHg as well.

3. The vacuum pump should be able to drain all the gas generated during the vacuum equipment process under its working pressure.

4, the correct combination of vacuum pumps. Due to the selective pumping of the vacuum pump, a pump may sometimes be selected that does not meet the pumping requirements. Several types of pumps are required to be combined to supplement each other to meet the pumping requirements. For example, the titanium sublimation pump has a high pumping speed for hydrogen, but it cannot whirl, and a three-pole sputtering ion pump (or a bipolar asymmetric cathode sputtering ion pump) has a certain pumping speed for argon. Combined, it will make the vacuum device a better degree of vacuum.

In addition, some vacuum pumps cannot work under atmospheric pressure and require pre-vacuum; some vacuum pumps have lower outlet pressures than atmospheric pressure and require a foreline pump, so they all need to be combined.

5, vacuum equipment requirements for oil pollution. If the equipment strictly requires no oil, a variety of oil-free pumps should be selected, such as water ring pumps, molecular sieve adsorption pumps, sputter ion pumps, and cryogenic pumps. If the requirements are not strict, you can choose to have oil pumps, plus some oil pollution prevention measures, such as adding cold traps, baffles, oil traps, etc., can also achieve clean vacuum requirements.

6. Understand the components of the gas being pumped. The gas contains no condensable vapor, no particulate dust, no corrosion, etc.

When selecting a vacuum pump, you need to know the gas composition and select the appropriate pump for the pumped gas. If the gas contains vapors, particles, and corrosive gases, additional equipment such as condensers, dust collectors, etc., should be installed on the inlet line of the pump.

7. How the oil vapor discharged from the vacuum pump affects the environment. If the environment does not allow contamination, an oil-free vacuum pump can be selected or the oil vapor can be discharged outdoors.

8. The vibration generated by the vacuum pump has no effect on the process and environment. If the process does not allow it, choose a non-vibrating pump or take anti-vibration measures.

9, vacuum pump price, operation and maintenance costs.