Interpretation of Vacuum Pump Selection Precautions for Vacuum Drying Ovens-

The vacuum pump is one of the necessary accessories of the vacuum drying oven. When customers choose a vacuum pump, they should pay attention to the following:

1. The working pressure of the vacuum pump should meet the ultimate vacuum and working pressure requirements of the vacuum equipment. For example: vacuum coating requires a vacuum degree of 110-5 mmHg, and the vacuum degree of the selected vacuum pump should be at least 510-6 mmHg. Generally, the vacuum degree of the pump is chosen to be half an order of magnitude greater than the vacuum degree of the vacuum equipment.

2. Correctly select the operating point of the vacuum pump. Each pump has a certain working pressure range, such as: diffusion pump is 10-3~10-7 mmHg, in such a wide pressure range, the pump pumping speed changes with the pressure and its sta working pressure rangewheat is 510-4~510-6mmHg. Therefore, the working point of the pump should be selected within this range, and it cannot work without 10-8mmHg for a long time. Another example is that the titanium sublimation pump can work at 10-2mmHg, but its working pressure should be less than 110-5mmHg.

3. Under its working pressure, the vacuum pump must be able to evacuate all the gas generated during the process from the vacuum equipment.

4. Combine the vacuum pump correctly. Due to the selective pumping of vacuum pumps, sometimes one pump cannot meet the pumping requirements, and multiple pumps must be combined to complement each other to meet the pumping requirements. For example, the titanium sublimation pump has a high pumping speed for hydrogen, but cannot pump helium, and the triode sputtering ion pump (or bipol asymmetric sputtering ion pumparea) has a certain pumping speed for argon. Combined, the vacuum device will get a better degree of vacuum. Additionally, some vacuum pumps cannot operate under atmospheric pressure and require a pre-vacuum; some vacuum pump outlet pressures are below atmospheric pressure and require a roughing pump, so they should all be used in combination.

5. Requirements for oil pollution of vacuum equipment. If the equipment is to be strictly oil-free, various oil-free pumps should be selected, such as: water ring pumps, molecular sieve adsorption pumps, sputter ion pumps, cryogenic pumps, etc. If the requirements are not strict, you may choose to have an oil pump, along with some anti-oil pollution measures, such as adding cold traps, baffles, oil traps, etc. ., can alsomeet clean vacuum requirements.

6. Understand the composition of the pumped gas, whether the gas contains condensable vapor, whether there are dust particles, whether it is corrosive, etc. When choosing a vacuum pump, you must know the gas composition, and choose the corresponding pump for the pumped gas. If the gas contains steam, particulates and corrosive gases, consideration should be given to installing ancillary equipment on the air inlet line of the pump, such as condensers, dust collectors, etc.

7. How does the oil vapor discharged from the vacuum pump affect the environment. If the environment does not allow pollution, you can choose an oil-free vacuum pump, or discharge the oil vapors outside.

8. Whether the vibrations generated by the vacuum pump will affect the process and the environment. If the process is not allowed, a vibration-free pump should be selected or anti-vibration measuresibrations should be taken.

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