With its powerful vacuum range and fast pumping speeds, the oil diffusion pump is a popular and reliable vacuum pump for many industrial and scientific applications.
Unlike some vacuum pumps, diffusion pumps contain no rotating parts. This means you don’t have to worry about problems with mechanical wear or failure. Diffusion pumps generally require minimal maintenance too.
You can reduce downtime and extend the life of your diffusion pump even further by following good practices in your day-to-day operations, and taking steps to avoid issues such as backstreaming.
Backstreaming occurs when oil doesn’t go down to the base of the pump like it should and instead gets drawn back up into the vacuum chamber. Backstreamed oil can react with heat and electrical discharge to produce deposits that contaminate the chamber walls and other pump parts. Such contamination can cause unwanted downtime and the eventual need to replace parts.
To avoid backstreaming and other problems that prevent your diffusion pump from working smoothly, follow these five simple operating tips.
1. Keep the Right Flow and Temperature in the Water Supply Line
If the water temperature is too high, the cooling coils won’t get the chamber walls cold enough to condense the vaporized pumping oil. Sluggish or blocked water flow also inhibits the cooling system, as the coils fail to get replenished with cold water and only heat up more from contact with the chamber walls.
In either case, overheated conditions inside the vacuum chamber can cause a buildup of oil vapor and consequent backstreaming. Always keep your water supply line within the temperature and flow range recommended in the pump operator’s manual.
2. Ensure the Vacuum Chamber Is Airtight
If the vacuum chamber has any leaks, oxygen from the atmosphere flows into the pump. When heated oil is exposed to oxygen, the oil burns and will eventually require replacement.
To protect the pumping oil and avoid taking your pump out of operation for service, check the vacuum chamber regularly for leaks.
3. Make Sure Your Pump Has an Integrated Heating System
Some diffusion pumps need to be paired with a separate heating component. This kind of paired configuration can cause the pump to overheat, as the independent heater controls fail to adjust for conditions within the pump.
To avoid pump overheating, always use a pump model like the Leybold DIP or DIJ which has an integrated heating system and controls the heater temperature directly.
4. Don’t Open the Backing Pump Valve at High Pressure
Opening the backing pump valve at high pressure doesn’t actually improve pumping performance. Instead, the increased pressure can blow the pumping oil away from the exhaust line and cause oil misting and backstreaming issues in the vacuum chamber.
Your diffusion pump will perform best when you keep the backing pump valve within the pressure range recommended in the pump operator’s manual.
5. Make Sure the Backing Pump Produces Adequate Flow
If your backing pump doesn’t have enough flow, high pressure can form in the exhaust line. This high pressure can result in unwanted oil misting and backstreaming in the vacuum chamber. Consult the pump operator’s manual for guidelines on maintaining the proper flow in your backing pump.
Get More From Your Diffusion Pumps
By following the proper care and operating practices, you will enjoy excellent, reliable service from your oil diffusion pump for years to come. If you need more advice on how to keep your diffusion pumps in peak condition, get in touch, and our team will be happy to help.
The above is intended only as a guide and is not a substitute for reading the operational manual. Always read the operational manual.