Cooling pre-admission

Fig. 2.22 Diagram of a Roots pump with pre-admission cooling...

The total emissions from the system are not increased by the large quantities of cold gas, since a closed refrigerating cycle is maintained by vray of an externally ananged gas cooler and condenser (Fig. 2.37). The hot exhaust gas is made to pass through the cooler and is partly returned in the form of cold gas for pre-admission cooling into the pump. The pump... 

S.3.4.6 Roots Vacuum Pumps with Pre-Admission Cooling Facility... 

The operating principle of a Roots vacuum pump with a pre-admission cooling facility is the same as for the pumps described above, but with the following difference. 

However, in the case of a vacuum pump with a pre-admission cooling facility, compressed and cooled down gas, cooled by means of a downstream gas cooler is admitted through the pre-admission channel into the pump chamber before the pump chamber is opened towards the exhaust port thereby ensuring direct... 

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