Performance Measurement And Application Of Multiple Molecular Drag Pump

A new kind of multiple molecular drag pump (MMDP), which has excellent performances in either high-vacuum, or mid-vacuum areas is invented recently. MMDP has a series of advantages: simple structure, large pumping speed, high working pressure and throughput, low power consumption and no hydrocarbon contamination, so it will has wide application in the future.In the paper, the principle and the structures of MMDP are discussed. The performances are tested, and its application in various fields, especially, in vacuum furnace is analyzed. One of MMDP has been used to replace an oil jet pump in a vacuum melting furnace. The experimental results are: Pumping time is reduced 50%. Energy consumption is only 3% of that of jet pump. Quality of melting alloys is improved notably.The research of this topic shows that not only MMDP has excellent performances in high-vacuum area, but also it has very attractive performances in mid-vacuum area: The maximum inlet pressure of MMDP is about 300 Pa. Pumping speed is nearly equal to that of root' pump at 20 Pa, and is more than 5 times of that at pressure below 1 Pa. Energy consumption is only 5% of that of root' pump. Furthermore, MMDP can separate vacuum chamber completely from fore-vacuum pumps at pressure region of 0.1-1 OOPa, which is the most serious region of hydrocarbon contamination, and create a new way to obtain clean vacuum. Hence, MMDP will bring to a revolution in the future vacuum technology.