A Brief Knowledge on Vacuum Pumps Oils Used in the Process


Vacuum pumps are a small yet vital part of a whole vacuum coating process. Over the top comes the importance of vacuum pumps meant for the completion of a work cycle. Just as the vacuum pumps form an unavoidable part of vacuum work process, so is oil for the vacuum pumps!

In everyday work life, we come across different types of oils used in vacuum pumps technically termed as synthetic vacuum pump oil, mineral oil, diffusion pump oil and many more. But it’s very important to learn, which pump needs which oil, else the result can be a blunder!

When connected with vacuum pumps to complete your task, first, you need to learn about the vacuum pumps and its parts, afterward familiarize yourself with the oils used to complete the vacuum cycles. Each pump type comes with its own conditions on the requirements for oil and in the long run, needs to be inspected as well as periodically replaced. These vacuum oils are specifically formulated for vacuum applications and come in varieties like hydrocarbon, silicone and other.

Description of Vacuum Oil

Vacuum pump oil is a mechanical lubricant forming a medium to trap gas molecules. Chemically vacuum pump oils are stable in nature, nonreactive to most types of gases and materials, and have low-vapor pressure.

Learn When to Change Vacuum Pump Oil

This absolutely depends on the type of oil used in the vacuum pump. On a rough estimation, it is recommended to change the synthetic vacuum pump oil after its initial 100 operating hours to ensure minimal internal wear.

For successive changes, verify the color of the oil, or perform tests on the vacuum pump oil to determine if oil change is anyways important for the whole system. Testing oil is quite constructive if in the total process it generates acids but not particles; in such cases, the oil composition degraded even though it looks clean.

How does dirty oil appear?

Before filling up the vacuum pump to the brim, save a small blended sample to occasionally compare the appearance of the oil in the vacuum pump. Change the pump oil if it gains an unusual color in the long run like contains small particles, darkens the color, or appears turbid or dirty!

General Guidelines on Vacuum Pump Oil

If the oil looks like honey – you have time to change it. If the vacuum oils look like molasses – it’s the right time to change it!

If in the work process, the pumps get exposed to acids, the oil appears proper although it is contaminated. On such occasions, it’s recommended to test your oil structure. Proper maintenance of the oil minimizes the internal wear and tear issue and increases the lifespan of the pump.

Before opening the filter house or tearing down away any of the units, be precautions because the hazardous gases concentrated in the vacuum pumps and filters. Take proper safety precautions prior to handling the mess!

Make sure vacuum pump has cooled down, but let the vacuum pump oil be a little warm for easy removal and oil changing process. The hotter the vacuum pump oil, the less viscous oil will be. If changing the oil of a cold unit, run the pump for a small period to ensure all particles and debris flow freely allowing draining properly.

How to Proceed with the Oil Draining

  1. Isolate the pump by disconnecting it from the process.
  2. Place a waste container and remove the oil drain plug to let the dirty oil flow out. When the flow slows down, screw back the oil-drain plug, switch on the pump for 10 seconds and switch it off again. Once more remove the oil-drain plug and drain out the remaining oil.
  3. Check flat gasket for corrosion or wear, if any replace it before pouring in clean oil.
  4. Remove the oil-filling plug and fill it with fresh oil to the top of the sight glass.
  5. Now, the system is ready for a fresh start!

Whether you are using synthetic vacuum pump oil or mineral oil or diffusion pump oil or any other, a good knowledge about it can make your work easy and more productive!