What is Vapor Pressure of Diffusion Pump Oil?

Diffusion Pump is last in the battery of pumps for creating vacuum. So, final vacuum that is achieved in a vacuum system is generated by diffusion pump. As we understand diffusion pump has no moving parts and is solely dependent on diffusion pump oil for vacuum creation. Diffusion pump oil is therefore a very critical consumable for vacuum applications. Hence it is very important to understand the properties of Diffusion Pump Oil.

diffusion pump

One of the foremost properties while considering diffusion

Pump oil isVapor Pressure.

  • What is vapor pressure of diffusion pump oil?

Vapor pressure is the pressure that vapors of oil exert at a given temperature.

  • What is desirable in the diffusion pump – low or high vapor pressure?

A low vapor pressure is most desirable in the pump.

  • Why is low vapor pressure oil better for the diffusion pump?

A higher vapor pressure will be counterproductive to creation of vacuum. So the vapor pressure should be as low as possible.

  • What should an ideal vapor pressure be?

After much experimentation and laboratory testing, world over, scientists and engineers have arrived at the conclusion that 2×10¯⁸ Torr at 25°C should be ideal vapor pressure for good quality diffusion pump oil.

  • Does SV-SIGMA diffusion pump oil meet the highest parameter set for the vapor pressure level?

Certainly. SV-SIGMA diffusion pump oil exhibits extremely low vapor pressure in the pump. Its vapor pressure at 25 degree C is 2×10¯⁸ Torr which is ideal and quite desirable. Very narrow molecular weight distribution of the oil ensures that no back streaming takes place.

vapor pressure in the pump

Supervac Industries (India) manufactures four types of diffusion pump oils ensuring highest standards of quality.

  1. SV-DELTA: Hydro-carbon diffusion pump oil.
  2. SV- SIGMA – (Tetramethyltetraphenyltrisiloxane)

Silicone diffusion pump oil (Exact equivalent and most reliable replacement of DC 704 diffusion pump oil)

  1. SV-SIGMA PLUS – (Pentaphenyltrimethyltrisiloxane)

Silicone diffusion pump oil (Exact equivalent and most reliable replacement of DC 705 diffusion pump oil)

  1. SV- SIGMA FAST – (Mixed Phenylmethyldimethylcyclosiloxane)

Silicone diffusion pump oil (Exact equivalent and most reliable replacement of DC 702 diffusion pump oil)

 Article is written by- Anshuman Punj CEO – Supervac Industries  www.supervacoils.com

 

 

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