1, The ultimate pressure of the vacuum pump should meet the process of work pressure.Choose the ultimate pressure of the vacuum pump is lower than the process requirements about an order of magnitude.
2, Each vacuum pump has a certain work pressure scope , therefore, the working point of the vacuum pump should be selected in this area, but can’t let it work in foreign work allows pressure to for long time.
3, vacuum pump under pressure from their work, should be able to come in during the process of vacuum process equipment all the gas quantity.
4, choose vacuum unit:
(1) when using a pump can not meet the requirement of the extraction and vacuum, need several pump combination, complement each other to meet the technological requirements.
(2) some vacuum pump can’t work under atmospheric pressure, to a vacuum;Before some vacuum pump outlet pressure below atmospheric pressure, need to pump, pump old need combined use.By the combination of vacuum pump, we call it a vacuum pump unit, it will have good vacuum and vacuum system is recommended.We should properly select combination of vacuum pump, due to the different vacuum pump for pumping gas have different requirements, such as: in the general case roots – rotary vane units shall not apply to contain more non-condensable gas system.
5, when you choose oil seal pump, you should first understand whether your vacuum system of oil pollution have requirements.When equipment strict with oil free, should choose all kinds of oil pump, such as water ring pump, cryogenic pump, etc.If not strict, you can choose to have the oil pump, add some oil pollution prevention measures, such as cold trap and oil baffle well, damper etc., can also meet the requirements of clean vacuum.
6, understanding is pumped gas composition, gas contains excluding condensable vapor, presence of dust particles, with or without corrosion, etc.Need to know when choosing a vacuum pump gas composition, gas is pumped to choose appropriate pump.If gas is contained in the steam, particles, and corrosive gas, should be considered in the pump inlet piping installation of auxiliary equipment, such as condenser, filter, etc.
7, when choosing oil seal vacuum pump, to consider the vacuum pump oil steam discharged (soot) impact on the environment.If pollution is not permitted in the environment, should choose oil-free vacuum pump, or the oil steam exhaust to the outside.
8, vacuum pump vibration of working with and without influence to the technological process and the environment, if the process does not allow, should choose no vibration of the pump and adopt measures to prevent vibration.
9, The price of liquid ring vacuum pump, operation and maintenance costs.
After we considered all kinds of situation, to finally determine a suitable for your solution:
(1) the smallest investment costs.
(2) the minimum operation cost.
(3) the first two reasonable feasible scheme of uniform distribution