One of the most critical parts of a vacuum system is the pump oil. “Oil” is a bit of a misnomer because modern pump oil technology has evolved well beyond the original distilled petroleum products. There are now double- and triple-distilled oils available, as well as hydro-treated oils, low sulfur oils, silicone-based synthetic oils, and flushing oils used to clean the pump. Due to the wide variety of formulations available, these are often now referred to as pump “fluids” rather than pump “oils”.
The oil in a vacuum pump serves several purposes. In addition to providing lubrication for mechanical components such as found in rotary vane pumps, the oil also provides the following:
- A seal across the vanes and duo seal between the high pressure and low-pressure side of the pump.
- Cooling of the pump by conducting heat from the stator to the outer casing where it can be dissipated.
- Protection of the metal parts from corrosion caused by the pumped gas