Multi-stage vacuum pump of the dry pump type

Abstract

A multi-stage vacuum pump of the dry pump type is disclosed. The multi-stage vacuum pump includes a plurality of pumping stages each respectively having an inlet and an outlet, the pumping stages being mounted in series between a suction port and a discharge port of the vacuum pump, characterized in that the vacuum pump also includes at least one valve configured to dump pressure from a pumping stage, said valve being arranged in the upper part of the vacuum pump, on the same side as the inlet of the pumping stage.

1 . A multi-stage vacuum pump of the dry pump type comprising:
 a plurality of pumping stages respectively comprising:
 an inlet; and 
 an outlet; 
   wherein the pumping stages are mounted in series between a suction port and a discharge port of the vacuum pump;   wherein the vacuum pump further comprises at least one valve configured to dump pressure from a pumping stage, said valve being arranged in the upper part of the vacuum pump, on the same side as the inlet of the pumping stage.   
     
     
         2 . The vacuum pump according to  claim 1 , wherein at least two pumping stages comprise a respective valve. 
     
     
         3 . The vacuum pump according to  claim 1 , wherein all the pumping stages comprise a respective valve. 
     
     
         4 . The vacuum pump according to  claim 1 , wherein the vacuum pump comprises at least one first valve arranged in the upper part of the vacuum pump on the same side as the inlets of the pumping stages and at least one second valve arranged in the lower part of the vacuum pump on the same side as the outlets of the pumping stages. 
     
     
         5 . The vacuum pump according to  claim 1 , wherein the at least one valve comprises at least one passage formed in the casing of the vacuum pump and connecting a central housing of a pumping stage and opening via a mouth that can be closed off by a respective mobile shutter of the valve. 
     
     
         6 . The vacuum pump according to  claim 5 , wherein the mouth is frustoconical. 
     
     
         7 . The vacuum pump according to  claim 5 , wherein the mobile shutter is chosen from a ball, a flat disk and a diaphragm. 
     
     
         8 . The vacuum pump according to  claim 1 , characterized in that the at least one valve comprises a spring. 
     
     
         9 . The vacuum pump according to  claim 1 , wherein the vacuum pump comprises a case fixed to the upper part of the casing of the vacuum pump, covering the valves and connecting the mouths of the passages of the valves to a common outlet. 
     
     
         10 . A multi-stage vacuum pump of the dry pump type comprising:
 a plurality of pumping stages respectively comprising:
 an inlet; 
 an outlet; 
   wherein the pumping stages are mounted in series between a suction port and a discharge port of the vacuum pump;   wherein the vacuum pump further comprises at least two valves configured to dump pressure from a respective pumping stage, the at least two valves respectively comprising at least one passage formed in the casing of the vacuum pump connecting a central housing of a pumping stage and opening via a mouth that can be closed off by a respective mobile shutter of the valve, the mobile shutter being chosen from a flat disk and a diaphragm.   
     
     
         11 . A multi-stage vacuum pump of the dry pump type comprising:
 a plurality of pumping stages respectively comprising:
 an inlet; and 
 an outlet; 
   wherein the pumping stages are mounted in series between a suction port and a discharge port of the vacuum pump;   wherein the vacuum pump comprises as many valves respectively configured to dump pressure from a pumping stage as there are pumping stages, so as to dump pressure from all of the pumping stages.