|
High Performance Diffusion Pumps, one of the important scientific instruments, are type of vacuum pumps that are designed to achieve higher vacuum or lower pressure, which is not possible, with the use of mechanical pumps alone. The diffusion pumps use a high-speed jet of vapor to lead residual gas molecules in the pump gullet down into the bottom of the pump and out the exhaust. This high-speed jet is achieved by boiling the fluid which is typically a low vapor pressure oil and directing the vapor through a multistage jet assembly. In some of the diffusion pumps, several jets are often used in series to enhance the pumping action. When it comes to the cooling of the high performance diffusion pump, the outside is cooled using either airflow or a water line. The working fluid condenses, as the vapor jet impacts the outer cooled shell of the diffusion pump, and is recovered, and then is directed back to the boiler. In such a case the pumped gases continues to flow to the base of the pump at increased pressure, and starts flowing out through the diffusion pump outlet, where the pressure is increased to ambient and exhausted by the secondary mechanical rough pump. It is better to take a note of the factor, which is that the oil is gaseous when entering the nozzles. It is there when in the nozzles, the flow changes from laminar, to supersonic and molecular. |
|||
|
|