How do you clean a diffusion pump?
For diffusion pumps using hydrocarbon based oils, you should dismantle the pump and clean it with a solvent as there will be residue that clog the pressure jets within the diffusion pump. Afterwards, rinse with alcohol and de-ionized water to remove the solvent.
Which oil is used in diffusion pump?
silicone oil
Most modern diffusion pumps use silicone oil or polyphenyl ethers as the working fluid.
Why silicone oil is used in diffusion pump?
As the use of hydrocarbon based pump oils are becoming less common, silicone diffusion pump fluid has become the ideal solution due to its low vapor pressure, excellent resistance to oxidation and radiation, chemical and thermal stability, and more importantly, a long life cycle before requiring an oil change.
Why is mercury used in diffusion pumps?
Diffusion pumps operate in an entirely different way; by heating the fluid (initially mercury and then later the low pressure oils) to a boil, and directing a high speed jet of vapours down onto a condensing surface, they are able to constantly push down air molecules into the bottom of the pump and thus maintain a …
When should I change my diffusion pump oil?
When should I change the diffusion pump oil? If you’re using hydrocarbon based diffusion pump oil, it should be changed approximately every 3-6 months. If you’re using silicone based diffusion pump oil, you generally do not need to replace the oil for at least 12-18 months.
How does an oil diffusion pump work?
How do oil diffusion pumps work? Oil diffusion pumps use a jet of hot oil molecules to transport gas molecules (in several stages) from the inlet to the exhaust. The nozzles accelerate the vapour to a speed exceeding the speed of sound (Laval nozzles), thus creating a high-speed vapour jet.
How do oil diffusion pumps work?
What is the difference between rotary pump and diffusion pump?
A diffusion pump, for example, uses oil vapor flow as the pumping mechanism while a rotary vane pump uses oil to lubricate and seal sliding joints between vanes and casing. So, in any wet pump, oil liquid and vapor coexist in the pumps vacuum volume.
How does a mercury diffusion pump work?
The diffusion pump uses the vapor of a boiling fluid to capture air molecules. The fluid is then moved to another location and cooled. The cooling forces the air molecules to be released. The combination of gravity and the downward direction of the vapors move the air molecules toward the bottom of the pump.
How does a mercury pump work?
The Sprengel pump is a vacuum pump that uses drops of mercury falling through a small-bore capillary tube to trap air from the system to be evacuated. The pump created the highest vacuum achievable at that time, less than 1 mPa (approximately 1×10−8 atm).
Does a vacuum pump need oil?
Vacuum pump oil is essential in keeping your vacuum pump operational. It lubricates the pumping machine, while also collecting contaminants and moisture from the evacuated systems. These application-specific oils should be pure from additives, (apart from anti-oxidation, anti-foaming, or corrosion-resistant additives).
What is a diffusion pump used for?
Diffusion pumps are probably the most commonly used mechanisms for creating a high vacuum in industrial vacuum processing. It is also commonly used in mass spectrometry, analytical instrumentation, research and development, and nanotechnology.
Why is mercury used as a diffusion pump fluid?
There is a number of advantages of using mercury as the diffusion pump fluid. The vapor pressure of the mercury is quite low. At the same time, the atomic weight is quite high. It reduces the chance of reverse diffusion in the system. The vaporization and liquefaction are quite easy for mercury.
Can a turbomolecular vacuum pump replace an oil diffusion pump?
Even as turbomolecular vacuum pumps have displaced most small laboratory sized oil diffusion pumps these days because of perceived ease of use and cleanliness, most high vacuum heat treating furnaces still rely on a large oil diffusion pumps to generate the pressures below about 10 -3 Torr needed for many metal conditioning processes.
How does a diffusion pump work and how does it work?
A diffusion pump works by boiling the fluid and then directing the hot oil vapor outwards and downwards through cone shaped jets at a very high speed. Molecules of gas entering the top of the pump are entrained in this vapor stream and redirected to the lower areas of the pump body.
What kind of oil is used in a diffusion pump?
The most frequently used diffusion pump fluid used in the heat treating industry for the last thirty or more years is silicone oil. It is available in three main grades, usually designated at 702, 704 and 705.