Addtime： 2020-07-16 Browse times： 2997
For the selection of liquid ring vacuum pump should pay attention to which of the details have its basis, the following for you to introduce liquid ring vacuum pump should pay attention to what matters of knowledge
1. Understand the composition of the extracted gas, whether there is condensable vapor in the gas, whether there is particulate dust, whether there is corrosiveness, etc. When choosing the vacuum pump, it is necessary to know the gas composition and select the corresponding pump for the extracted gas. If the gas contains steam, particles and corrosive gas, it should be considered to install auxiliary equipment such as condenser and dust collector on the air inlet pipeline of the pump.
2. Select the working point of liquid ring vacuum pump correctly. Each pump has a certain working pressure range, such as: LEM series water ring vacuum pump working pressure range of 760mmhg ~ 25mmhg (absolute pressure). In such a wide pressure range, the pumping speed of the pump varies with the pressure (refer to the performance curve of the pump for detailed changes), and its stable working pressure range is 760 ~ 60mmhg. Therefore, the working point of the pump should be selected in this range, rather than let it work for a long time under 25 ~ 30mmhg.
3. The influence of oil vapor discharged from liquid ring vacuum pump on environment is discussed. If the environment does not allow pollution, you can choose an oil-free vacuum pump, or exhaust the oil vapor to the outdoor. Whether the vibration generated during operation has any influence on the process and environment. If the process is not allowed, the pump without vibration should be selected or anti vibration measures should be taken. The price, operation and maintenance cost of vacuum pump.
4. Correct combination of liquid ring vacuum pump. Because of the selective pumping, sometimes one kind of pump can't meet the requirement of air extraction. It needs several pumps to combine and supplement each other to meet the pumping requirements. If the titanium sublimation pump has a high pumping speed for hydrogen, but can not pump helium, and the tripolar sputtering ion pump (or bipolar asymmetric cathode sputtering ion pump) has a certain pumping speed for argon, the combination of the two will make the vacuum device get better vacuum degree. In addition, some vacuum pumps can not work under atmospheric pressure and need pre vacuum; some vacuum pump outlet pressure is lower than atmospheric pressure, need the front stage pump, so all need to combine the pump.
5. Its working pressure should meet the limit vacuum and working pressure requirements of vacuum equipment. For example, a vacuum drying process requires a working vacuum of 10mmhg. The limit vacuum degree of the selected vacuum pump should be at least 2mmhg, and it is better to reach 1mmhg. Generally, the limit vacuum degree of pump is higher than that of vacuum equipment by half to one order of magnitude.
6. Requirements of vacuum equipment for oil pollution. If the equipment is strictly required to be oil-free, all kinds of oil-free pumps should be selected, such as: water ring pump, molecular sieve adsorption pump, sputtering ion pump, low-temperature pump, etc. If the requirements are not strict, you can choose to have an oil pump, plus some anti oil pollution measures, such as adding cold trap, baffle, oil trap, etc., can also meet the requirements of clean vacuum.
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