Claw Vacuum Pumps Northey Principle

Claw Vacuum Pump with Inner Compression So-called claw vacuum pumps have been developed both with, and also without inner compression of the taken in vapours, respectively gases. Such pumps with inner compression were and are being manufactured of the three stage type for chemistry applications and attain pressures below 1 mbar absolute. 

In parallel to each intake cycle, the gas which was in each case taken in before is compressed. This compression is effected by gas flowing backwards into the pump chamber (opening 3). As soon as one impeller opens the intake slot, the second impeller opens in the direction of gas inlet 3 on the exhaust side. The venting gas which is at atmospheric pressure flows into the pump chamber and increases the particle density in the pump chamber to the level of atmospheric pressure. 

Since venting with cold gas is effected by a condenser related to the vacuum pump, intensive and effective cooling of the inner pump sections is attained. Finally the taken in gas and the warmed up cold gas is discharged through the exhaust gas slot 5 and is cooled down again in the downstream condenser (gas cooler) and freed of condensable substances. 

An important characteristic of this claw vacuum pump is, that the two shafts which drive the claw impellers, are exclusively suspended within the gear. A bearing on the pump chamber side does not exist. Through this simple design, this type 

3 New Developments of Screw Vacuum Pumps for the Area of Process Chemistry 

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