oil-type rotary vane vacuum pump of maintenance

Oil-type rotary vane vacuum pump is a very mature and reliable vacuum pump, usually also called oil pump, mechanical pump, rotary vane pump, etc. It is low-cost and can achieve a good vacuum degree. It is widely used in vacuum packaging machines, vacuum heat treatment, coating, Mass spectrometers, sample pretreatment, freeze drying, glove boxes, leak detection and other applications that are not sensitive to oil vapor, and are often used as backing pumps for ultra-high vacuum molecular pumps.

Single-stage or double-stage, the one that suits you is the best

The oil-type rotary vane pump is divided into single-stage and double-stage. The two-stage rotary vane pump compresses the gas twice, which effectively reduces the backflow, so the vacuum is better, but the condensable gas is also easier to enter the pump. Condensation destroys vacuum pump oil. It is very important to choose a suitable vacuum pump according to the actual application.

Generally speaking, for applications that require a relatively high degree of vacuum and less condensable gases, use a two-stage rotary vane pump, such as the 2XZ-C, 2X-A series of EVP VACUUM; for applications with more condensable gases, choose Single-stage rotary vane pumps, such as EVP VACUUM single-stage rotary vane pump SV series.

At the same time, EVP VACUUM has specially developed an oil-free scroll vacuum pump (EVP-PB) for laboratories and mass spectrometry instruments, which has high performance temperature and can also be used to pump non-corrosive organic solvent gases.

Proper use of gas ballast

Some processes themselves will generate a lot of water vapor, such as vacuum drying, vacuum freeze drying, etc., and the inner wall of the vacuum chamber will also absorb moisture (especially in the humid season), and these moisture will vaporize under vacuum to form a large amount of water. steam. After the water vapor is compressed in the vacuum pump, it will condense into liquid water and accumulate in the pump, causing problems such as pump oil emulsification, shaft seal oil leakage, internal rust, increased noise, and poor ultimate vacuum.

Avoiding condensation of water vapor requires the use of gas ballast. The gas ballast plays the role of adding air into the vacuum pump. When the gas ballast port is opened, the external dry gas is sucked in to dilute the water vapor in the pump, thereby avoiding the condensation of water vapor.

For applications with high water vapor content, it is recommended to keep the gas ballast open; for applications that require ultimate vacuum or low water vapor content, you can let the pump continue to run with gas ballast for about 1 hour when drainage is required, and then close the gas ballast port again .

Air filters must be installed for applications with a lot of dust

In dusty applications, an air inlet dust filter should be added to prevent dust inhalation. Otherwise, a large amount of dust will enter the pump cavity, which will cause serious wear of the pump cavity and make the whole pump lose its maintenance value.

No working under high pressure for long periods of time

Many rough vacuum pumps, including oil rotary vane vacuum pumps, can be started directly from atmospheric pressure, but it does not mean that they can work under atmospheric pressure or poor vacuum for a long time. When the rotary vane vacuum pump works under a relatively poor vacuum degree for a long time, a large amount of lubricating oil will be sprayed out from the exhaust port in the form of oil mist or even oil droplets, resulting in the loss of pump oil; in addition, when the vacuum degree is relatively poor, the vacuum pump Fever is also more severe.

Try to avoid cold start

Oil rotary vane vacuum pumps generally require the ambient temperature to be above 5 degrees Celsius. When the temperature is too low, the viscosity of the lubricating oil will drop and even sand will form. At this time, power on and start will cause serious failures such as motor burnout, coupling damage, and even rotor twisting.

Regular maintenance

The pump oil of the oil rotary vane pump plays the role of lubrication, sealing and cooling. The dust in the process gas and the metal debris worn off during the operation of the pump will enter the pump oil, and the condensable steam that is not successfully discharged will also be condensed. After mixing in the pump oil, if it reaches a certain level, it will cause the pump oil to change color, emulsify, and reduce the lubricating performance. Therefore, it is necessary to replace the pump oil regularly. Some rotary vane pumps are equipped with special oil filters. To be replaced together. The frequency of pump oil replacement depends on the actual process and the type of pump oil. It is generally recommended to replace it every six months to one year.

In case of abnormality, check and repair in time

The rotary vane vacuum pump needs to be inspected and repaired in time every 5 years, or when the pump has abnormal noise, high pump temperature, oil leakage from the shaft seal, etc. during operation, so as to avoid more serious damage.

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