Vacuum pump having a silencer

Abstract

A vacuum pump is provided that includes rotor elements arranged in a suction chamber. An outlet duct is connected to an exhaust pipe. For the purpose of silencing, sound expansion spaces are provided in the outlet duct, which are integrated into the pump housing. Alternatively or in addition to these sound expansion spaces, sound expansion spaces may be provided in an inlet duct which is used for the inlet of gas ballast, said sound expansion spaces being preferably likewise integrated into the pump housing.

What is claimed is: 
     
         1 . A two-shaft vacuum pump, comprising:
 a pump housing defining a suction chamber and having a gas inlet and a gas outlet,   rotor elements arranged in said suction chamber for forming a plurality of successive pump stages,   a discharge duct connected to said gas outlet, and   at least one sound expansion space arranged between duct sections of said discharge duct, the at least one sound expansion space being partially integrated into said pump housing and partially integrated into a removable pump housing cover, the at least one sound expansion space having at least one change in cross-section.   
     
     
         2 . The vacuum pump according to  claim 1 , further comprising:
 an inlet duct for gas ballast connected to one of said pump stages, and   at least one second sound expansion space arranged between duct sections of said inlet duct, the at least one second sound expansion space being partially integrated into said pump housing and partially integrated into the removable pump housing cover, the at least one second sound expansion space having at least one change in cross-section.   
     
     
         3 . The vacuum pump according to  claim 2 , wherein in the inlet duct at least two identically configured sound expansion spaces and in the outlet duct at least two identically configured second sound expansion spaces are arranged. 
     
     
         4 . The vacuum pump according to  claim 1 , wherein at an inlet opening of the at least one sound expansion space a multiple increase of the cross-section is realized. 
     
     
         5 . The vacuum pump according to  claim 1 , wherein two identically configured sound expansion spaces are arranged one behind the other in the direction of flow. 
     
     
         6 . The vacuum pump according to  claim 1 , wherein an inlet opening and an outlet opening of the at least one sound expansion space are arranged in a staggered manner relative to each other. 
     
     
         7 . The vacuum pump according to  claim 1 , further comprising a gas ballast inlet which is open against the atmosphere or a rotary valve which is provided at the gas ballast inlet. 
     
     
         8 . The vacuum pump according to  claim 1 , further comprising at least one duct section has connected thereto a pipe section projecting into the at least one sound expansion space. 
     
     
         9 . A two-shaft vacuum pump, comprising:
 a pump housing a gas inlet and a gas outlet;   pump housing cover removably secured to the pump housing to define a suction chamber therein;   rotor elements arranged in the suction chamber and forming a plurality of successive pump stages;   a discharge duct connected to said gas outlet; and   a first sound expansion space defined by a change in cross-section of the discharge duct, the first sound expansion space being partially integrated into the pump housing and partially integrated into the pump housing cover.   
     
     
         10 . The vacuum pump according to  claim 9 , further comprising a second sound expansion space defined by another change in cross-section of the discharge duct. 
     
     
         11 . The vacuum pump according to  claim 10 , wherein the second sound expansion space is partially integrated into the pump housing and partially integrated into the pump housing cover. 
     
     
         12 . The vacuum pump according to  claim 10 , wherein the first and second sound expansion spaces are identically configured. 
     
     
         13 . The vacuum pump according to  claim 12 , wherein the first and second sound expansion spaces are arranged one behind the other in a direction of flow. 
     
     
         14 . The vacuum pump according to  claim 9 , wherein the first sound expansion space has an inlet opening with multiple changes of the cross-section. 
     
     
         15 . The vacuum pump according to  claim 9 , further comprising:
 an inlet duct connected to one of the plurality of successive pump stages; and   a third sound expansion space defined by a change in cross-section of the inlet duct, the third sound expansion space being partially integrated into the pump housing and partially integrated into the removable pump housing cover.   
     
     
         16 . The vacuum pump according to  claim 15 , further comprising a fourth sound expansion space defined by another change in cross-section of the discharge duct. 
     
     
         17 . The vacuum pump according to  claim 16 , wherein the second sound expansion space is partially integrated into the pump housing and partially integrated into the pump housing cover. 
     
     
         18 . The vacuum pump according to  claim 16 , wherein the third and fourth sound expansion spaces are identically configured. 
     
     
         19 . The vacuum pump according to  claim 15 , wherein the third sound expansion space has an inlet opening with multiple changes of the cross-section.