What is the working principle of diffusion pump?
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.
What is the operating range of diffusion pump?
DIP Oil Diffusion Pump The working principal of diffusion pumps is generally based on the transporting capacity of the vapor jet for gases. The pumping speed ranges from 3,000 l/s to 50,000 l/s and has an operating pressure range of < 10-2 to 10-7 mbar.
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 does a diffusion pump need a cooling system?
The pump external housing (or shell) is generally water-cooled to prevent thermal runaway. In all diffusion pumps, a small amount of backstreaming, movement of oil molecules into the vacuum chamber, occurs. In many applications, this is acceptable.
What are the important characteristic of a diffusion pump?
Unlike turbomolecular pumps and cryopumps, diffusion pumps have no moving parts and as a result are quite durable and reliable. They can function over pressure ranges of 10−10 to 10−2 mbar. They are driven only by convection and thus have a very low energy efficiency.
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.
What are the important characteristics of a diffusion pump?
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 …
What is a rotary pump and its operating principle?
Rotary pumps are designed with very small clearances between rotating parts and stationary parts to minimize leakage (slippage) from the discharge side back to the suction side. Rotary pumps are designed to operate at relatively low speeds to maintain these clearances.
What are the types of rotary pumps?
There are 4 types of Rotary Pumps:
- Screw Pump:
- Gear Pump:
- Lobe Pump:
- Vane Pump:
- Rotary Pumps Applications:
Where are rotary pumps used?
The main applications where rotary pumps are used are – Refrigeration Heating and Air Conditioning. They are also used as pumps carrying out high viscosity substances transfer such as lubricating oil. Lobe-type, flexible-vane or screw pump are generally used for high viscosity or metering.
What are the different types of rotary pump?
How is oil accelerated in a diffusion pump?
Diffusion pump oil is boiled into a vapor in the boiler section of the pump (see figure 1) and accelerated to sonic speed (as a vapor) through precisely controlled jets. Figure 1. Boiler section on a DIJ20 Diffusion Pump.
How does a diffusion pump differ from a mechanical pump?
Diffusion pumps differ from conventional mechanical pumps in that they use a high – speed jet of fluid to direct gas molecules in the pump throat down to the bottom of the pump and out the exhaust, which is usually called the foreline.
How can I extend the life of my diffusion pump?
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.
Where does the gas go in a diffusion pump?
As the gas travels toward the walls of the pump chamber, it traps air molecules along the way through “diffusion”.