The manufacturer of silent oil-free vacuum pump will let you know the selection and application of oil-free vacuum pump
General requirements for oil-free vacuum pump: (1) cleaning, (2) safety, (3) wear resistance, (4) low cost, (5) convenient maintenance, (6) stable performance, (7) low vibration noise. Only in this way can the pump have the value of use and promotion.
(1) For cleaning requirements, those vacuum pumps lubricated with oil have a potential source of oil vapor pollution. This problem should be well solved in the absence of oil pumps, and the other is the source of dust pollution. In order to reduce or remove the dust pollution in the vacuum system, the oil-free dry pump can be considered as an oil-free, dust-free and truly clean vacuum pump.
(2) Requirements for safety. Pumping out some active gases and some by-products will deposit in the pump. In serious cases, it will interfere with the normal operation of the pump and reduce the service life of the pump. It is safe to pump oxygen without an oil pump.
(3) Operating costs. Using PFPE pump oil is expensive. Although the service life is long, users need to change the pump oil every six months, and the price is about $200 per 1kg. Therefore, the dry-type pump must have a low cost, which makes users feel that it is cheaper to use no oil pump.
Is the dry pump really oil-free? According to the previous definition, the extraction chamber is oil-free. The mechanical transmission part also needs oil lubrication, such as multi-stage Roots pumps, claw pumps and screw dry pumps. The bearings of the transmission gears need lubrication. The labyrinth seal structure is used to isolate the pump cavity and gearbox. The simple method is to fill dry inert gas between the pump cavity and the parts that need lubrication, or install the sealing ring. In particular, roots pump must have good anti backflow measures. Most Roots pumps are used under low pressure. The labyrinth structure can prevent the lubricating oil from entering the pump chamber, but it may allow the gas to pass through, because the gas pressure in the gearbox is not limited. If the gas pressure in the gearbox is greater than the pressure in the pump chamber, there is a pressure gradient, and the oil vapor in the gearbox will diffuse into the pump chamber. Therefore, the structural design of roots pump should be well considered. Decompress and pre pump the oil pool in the gearbox, control the gas pressure in the gearbox, and isolate the oil pool from the pump cavity through the lip seal ring.