Vacuum Pump Maintenance

Posted by Ken Bandoly on Aug 16th 2019


Operation of a vacuum pump would seem to be straight forward, but there’s a little more to it than just connecting the hoses and turning it on. Be sure to read the manufacturer supplied owners manual for your pump for proper operating procedures. If your pump did not come with a manual, you have a second hand pump or for whatever reason can not seem to locate a manual for your pump, there are some basics you should be aware of. Rotary vein pumps use the oil to not only lubricate moving parts within the pump, but also to provide a good seal within the inner workings. When turning your pump off, it is very important to allow it time to run without a vacuum applied. That means it must run without a chamber attached and allowed to pull in air. This allows the pump to push out any excess oil within the inner workings. Turning the pump off while a vacuum is applied will pull oil into the inner cylinder where the vacuum remains. Oil is not compressible, if the inner cylinder fills with oil the veins will encounter higher forces and the motor will be overburdened when it starts. Over time this will wear out your pump much faster than normal. If too much oil is pulled into the pump, the cylinder may become filled. Unable to compress the liquid, the pump may completely seize or become significantly damaged depending on the design of the pump.

Oil Change

One of the most important things you can do to improve the longevity of your rotary vein vacuum pump is to keep the oil fresh and clean. When you first start pulling a vacuum on your chamber, the area between the resin surface and the lid is full of air. This air in the chamber will match the humidity of your work area. As the air is removed, so too is the moisture within it. This and any moisture contained in the wood, resin and any dyes you might be using will eventually end up trapped in the oil of your pump. The oil in the pump is responsible for more than just lubricating parts, it also helps provide a seal in order to achieve proper vacuum. If the oil is too low or contaminated, the pump will not be able to maintain proper efficiency and will not pull as deep of a vacuum. If the oil level is too high, it may be forced out the exhaust of the pump.

Changing the oil in the pump should be done while the pump is still warm. If you have not run your pump in a while or it has already cooled down, turn it on and let it run for a while to warm up. When the oil in the pump cools, the water, oil and other contaminates will separate. Draining the oil cooled will leave a film of moisture and contamination inside the pump. This will encourage rust and corrosion and shorten the life of the pump.