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Composing Oil Diffusion Pumps

Oil diffusion vacuum pumps

The oil diffusion pump are family member of fluid-entrainment pumps

Leybold’s innovative heating system offers a unique advantage by reducing the average power consumption and provides significantly quicker heating-up time as compared to conventional Diffusion and Oil Booster pumps. Offering customized solutions for your application that needs high pumping speed and high vacuum, high gas throughput or when you need a large industrial booster pump along with various energy efficiency options like Energy Efficiency Controller (EEC) to reduce your carbon footprint. Leybold’s innovative direct heating concept brings a smart heating process for high energy efficiency!

Oil Diffusion pumps produce high vacuum and operate with a fast-moving stream of pump fluid in vapor form (oil vapor). All fluid-entrainment pumps have a similar pumping mechanism where the pump fluid is heated by the electrical heater vessel and the oil vapor expands after passing through the jet stack nozzles. The pumped gas molecules diffuse into the vapor stream and exit out of the pumping chamber.

The molecules of the pump fluid stream transfer by way of impact impulses to the gas molecules in the direction of the flow. Thus, the gas which is to be pumped is moved to a space with higher pressure. This technology is wear -free as it doesn’t need any moving parts. In oil diffusion pumps, corresponding vapor pressures increases during operation depending on the type of pump fluid (silicon- or mineral- oil) and the temperature as well as the design of the nozzles.

The vapor jet does not enter the process chamber since it condenses after ejecting through the nozzles on the cooled outer walls of the pump. Furthermore, the modern unique baffle design reduces the oil back streaming and oil consumption through improved condensation surface design. This simple physical mechanism makes Diffusion pump a robust technology.

The backing pressure in the pump must be low enough to allow the vapor to flow out. To ensure this, corresponding backing pumps are used, typically mechanical fore vacuum pumps from Leybold. The fore vacuum pressure also influences the vapor jet and becomes detrimental if its value exceeds a certain critical limit called maximum backing pressure or critical fore line pressure.


Unique jet stage nozzle system

The vapor stream emanates from the nozzles with supersonic speed to obtain as high a vapor stream velocity as possible. The jet stage nozzle system has 3-5 stages that results in the amazing pumping speed of Leybold oil diffusion pumps. The pump fluid vapor, which constitutes the vapor jet, is condensed at the water cooled wall of the pump housing, whereas the transported gas is further compressed (gas throughput), usually in one or more succeeding stages, before it is removed by the backing pump.

The compression ratios, which can be obtained with fluid entrainment pumps, are very high: if there is a pressure of 10-7 mbar at the high vacuum inlet port of the fluid-entrainment pump and a backing pressure of 10-1 mbar, the pumped gas is compressed by a factor of 10-6. This compression ratio ensures a stable high vacuum pressure for the application process. The ultimate pressure of fluid entrainment pumps is restricted by the value for the partial pressure of the fluid used at the operating temperature of the pump. With our high-quality diffusion pump oil LVO 500, LVO 521 and LVO540 we guarantee outstanding performance.

Leybold series oil diffusion pumps optimized for your application

Each of these product lines are optimized for costumers’ applications!

  • DIP-Line is the perfect pump for maximum pumping speed at the lowest pressure!
  • DIJ-Line realizes the maximum gas throughput already 2x10-3 mbar, which is realized by its 5-stage nozzle system.
  • Finally, the OB-Line, which is the best solution for maximum gas throughput in combination with highest pumping speed for the toughest applications!

Advantages of Leybold oil diffusion pumps

  • Energy efficient with low carbon footprint
  • Performance driven
  •  Extended uptime
  • Relatively low investment costs
  • IoT ready
  • Easy to service

Oil diffusion pumps often provide the most efficient and cost-effective environment for vacuum production processes. A small investment in timely maintenance can yield a high return in the ongoing high-level performance of your production system.

Oil diffusion pumps are well-suited for operation in several industrial application:

  •  Web coating
  • Optical coating
  • Metallurgy
  • Steel degassing
  • Heat Treatment vacuum furnaces
  • E-beam welding
  • Research and development 
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