DIFFUSION PUMP OIL USAGE TIPS
First, before we move forward with usage tips, one of the most important aspects of ensuring optimal performance is the use of high quality diffusion pump oil. It does not need to be from us, however, you’ll find the use of high quality pump oil, even at higher cost will lead to better overall cost-effectiveness, smoother operation, stability, and reduced maintenance costs and headaches in the long run. Lower quality diffusion pump oils often work well in the short run where problems such as crystallization start to occur several months into usage. As the oil works in very rugged conditions, lower quality oil may also breakdown in layers or become charred. This is mainly caused by cutting corners to save costs during the manufacturing process. While lower quality oils will usually not damage the diffusion pump, it will require cleaning out the entire system whereby wasting the pump oil you already have inside. Below are usage tips that will help you extend the life cycle of diffusion pump oil.
- Make sure you’re using the correct model of diffusion pump oil according to your vacuum requirements and apply the correct heating temperature.
- Setup a schedule and top up the oil at regular intervals. As the same amount of heat is being applied to lowering volumes of oil, over heating and the accelerated loss of pump oil will occur.
- If you’re choosing between hydrocarbon-based or silicone-based pump oil, the silicone based pump oil is the clear winner. Silicone based diffusion pump oil will last at least 3-4 times longer and does not char or clog the pressure jets.
- Silicone-based oils decompose when exposed to alkali metals such as hydroxides of sodium, potassium, cesium. Therefore, if the vacuum process requires the use of these metals, make sure to keep them away from the pump chamber.
- For water-cooled pumps, make sure to use only purified water to reduce scaling. Additionally, check the pressure and temperature of the water to ensure the walls of the pump is properly cooled. Improper cooling of the walls may lead to over heating of the diffusion pump oil causing excessing loss of oil through back streaming, the loss of oil backing into the vacuum environment.
- Routinely check the temperature gauges to ensure they are functioning properly.
- Check the pressure of your fore pump or rotary pump to ensure you have proper exiting pressure.
- Do not expose heated oil to air, this will cause the oil to thicken.
- To ensure no air enters the diffusion pump, an essential step is making sure the o-rings and joints are properly greased with high quality silicone vacuum grease.
- Use a baffle at the mouth of the diffusion pump to keep heavier oil vapors from exiting while allowing air to flow in.
- Use a cold cap at the top of the nozzle assembly within the diffusion pump to condense vapors in that area. This will help prevent back streaming.