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How to maintain a unipolar rotary vane pump?

maintain a unipolar rotary vane pump

Last time BTLAS shared some tips for maintaining your double-stage rotary vane pump. Today, we’re back with some maintenance tricks to help keep your single-stage rotary vane pump running smoothly and extending its lifespan.

Whether you have a single or double-stage pump, installing an oil mist separator can provide excellent protection for your pump.

In fact, there are now original replacement oil mist separators available in China that offer performance on par with imported products, so vacuum pump users no longer need to worry about long lead times and high prices.

Let’s take a closer look at how to maintain the SV105 FP sealed single-stage rotary vane pump.


For a sealed rotary vane pump, it’s important to use the recommended oil specified on the pump body and change the oil regularly, while also observing the oil mist separator and oil filter.

The first step in maintaining the SV series is learning how to correctly replace the oil and oil filter. Be sure to change the oil soon after stopping the pump, when the oil is still warm, to prevent condensation and ensure smooth drainage.

Unscrew the drain plug and pour the old oil into a container. The rest of the steps are similar to those for a double-stage rotary vane pump: partially drain the oil, screw the plug back on, briefly start the pump (for less than 10 seconds), stop the pump, and then fully drain the remaining oil.

Make sure the sealing ring on the oil filling port is in good condition; if it shows signs of wear or damage, replace it with a new part. Wipe off any excess oil around the oil drain port, screw the plug back on, remove the oil filling plug, and refill the pump with fresh oil.

Check that the oil level is not below the minimum fill line or above the maximum fill line. After adding the new oil, run the pump for a short time to flush it out.

You can change the oil and oil filter simultaneously using an oil filter wrench to unscrew the old filter and install the new one. Wipe away any excess oil with a dry cloth.

vacuum pump filter


To change the oil mist separator on a low-suction SV series pump, remove the filter and place the screws in order. Use an original replacement filter, making sure the seal gasket is undamaged and the O-ring inside the filter is functioning properly.

If either is damaged, replace it before installing the oil mist separator. Ensure that the threads on the front screw protrude by 1mm, and install the separator with the oil guide edge facing down so that gravity helps the oil flow downward.


For larger suction SV series pumps, open the cover, remove the W-shaped metal bracket, spring, and filter. Check that the filter mounting surface inside the tank is intact.

Replace the O-ring on the exhaust port plate, lubricate it with vacuum grease, and reinstall it. Use a replacement filter, ensuring that the new filter’s side seal ring is intact. Place the new oil mist separator in the correct position inside the tank, return the spring and W-shaped bracket, and make sure the spring is behind the metal bracket.

Adjust the oil guide edge of the filter to face down. Clean off any residual oil from the cover, insert the exhaust port plate into the W-shaped metal bracket using two positioning pins, and tighten the screws to the tank using an internal hexagonal wrench.

Adjust the gas venting valve to the “open” position by turning it outward or the “closed” position by turning it inward.


BTLAS vacuum pump oil mist separators are designed as original brand replacements, using the same filter materials as the original manufacturer.

They undergo 15 inspection processes and come with test reports, receiving consistent praise from customers. Contact us today to learn more about that.

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