Single stage piston compressor or multistage piston compressor for cooling of an electrical motor for a single stage piston compressor or for a multistage piston compressor

Abstract

A multistage piston compressor and a method for cooling of an electrical motor for a multistage piston compressor. Conventional piston compressors produce a high part of heat dissipation. This influences negatively the energy balance of the piston compressor and requires a high expenditure in cooling agents for conserving and treating with care the piston compressor. It is therefore disclosed to furnish the always present volume changeable free chamber ( 19 ) at the piston compressor ( 1 ) as a pressure chamber and a suction chamber, and to connect this volume changeable free chamber ( 19 ) to the atmosphere through the inner chamber of the electrical motor ( 2 ).

1 . A multistage piston compressor, comprising a piston compressor ( 1 ), an electrical motor ( 2 ) and a mechanical drive ( 3 ), which mechanical drive ( 3 ) converts the rotating motion of the electric motor ( 2 ) into an oscillating linear motion and transfers the oscillating linear motion onto the piston compressor ( 1 ), wherein a multistage piston compressor ( 1 ) has at least one volume changeable low-pressure chamber ( 8 ) with a low-pressure piston ( 9 ) and at least one volume changeable high-pressure chamber ( 10 ) with a high-pressure piston ( 11 ) and wherein the low-pressure chamber ( 8 ) and the high-pressure chamber ( 10 ) of the multistage piston compressor ( 1 ) are connected by a bypass channel, ( 17 ) and wherein the low-pressure piston ( 9 ) and the high-pressure piston ( 11 ) are formed as a single piece and wherein a volume changeable free chamber ( 19 ) is disposed between the low-pressure piston ( 9 ) and the high-pressure piston ( 11 ), 
 wherein the volume changeable free chamber ( 19 ) of the piston compressor ( 1 ) is furnished as a pressure and suction chamber for a separate cooling air stream and    wherein the volume changeable free chamber ( 19 ) is connected to the atmosphere through the inner chamber of the electric motor ( 2 ).    
     
     
         2 . The single stage and multistage piston compressor according to  claim 1 , wherein the volume changeable free chamber ( 19 ) has a connection to the outer atmosphere through an admission check valve ( 27 ).  
     
     
         3 . The single stage or multistage piston compressor according to  claim 1 , wherein the low-pressure chamber ( 8 ) has a suction chamber ( 23 ) predisposed and wherein the suction chamber ( 23 ) is connected on the one hand to the low-pressure chamber ( 8 ) and on the other hand to the inner chamber of the electrical motor ( 2 ) and to the outer atmosphere.  
     
     
         4 . The single stage or multistage piston compressor according to  claim 3 , wherein the inlet opening ( 24 ) of the suction chamber ( 23 ) or the third casing opening ( 22 ) of the electrical motor ( 2 ) are disposed outside of the dirt and water endangered region for safeguarding the kind of protection of the electrical motor ( 2 ).  
     
     
         5 . A method for cooling of an electrical motor ( 2 ) for a multistage piston compressor ( 1 ), 
 wherein the air suctioned and ejected by a volume changeable free chamber ( 19 ) of the piston compressor ( 1 ) is employed as a cooling agent for the electric motor ( 2 ),    wherein the volume changeable free chamber ( 19 ) is disposed between two neighboring pressure pistons of different size.    
     
     
         6 . The method according to  claim 5 , wherein the air moved by the piston compressor ( 1 ) is alternatingly suctioned in from the atmosphere through the inner chamber of the electric motor ( 2 ) and removed into the atmosphere.  
     
     
         7 . The method according to  claim 5 , wherein the air moved by the piston compressor ( 1 ) is separately suctioned in from the atmosphere and removed into the atmosphere through the inner chamber of the electrical motor ( 2 ).  
     
     
         8 . The method according to  claim 6 , wherein the air moved by the piston compressor ( 1 ) is led simultaneously into the low-pressure chamber ( 8 ) of the compressor ( 1 ) through the inner chamber of the electric motor ( 2 ).  
     
     
         9 . A piston compressor apparatus comprising 
 a movable low pressure piston forming a volume changeable low-pressure chamber ( 8 );    a movable high-pressure piston ( 11 ) forming volume changeable high-pressure chamber ( 10 );    a common piston rod ( 12 ) connecting the low-pressure piston to the high pressure piston;    a bypass channel ( 17 ) disposed in the common piston rod and connecting the low-pressure chamber ( 8 ) and the high pressure chamber ( 10 ) and wherein the low-pressure piston ( 9 ) and the high-pressure piston ( 11 ) are formed as a single piece;    a volume changeable free chamber ( 19 ) disposed between the low-pressure piston ( 9 ) and the high-pressure piston ( 11 ), wherein the volume changeable free chamber ( 19 ) changes volume together with a motion of the low-pressure piston and of the high pressure piston, and wherein the movable low pressure piston ( 9 ), the movable high-pressure piston ( 11 ), the bypass channel ( 17 ) and the volume changeable free chamber ( 19 ) form a piston compressor ( 1 );    an electrical motor ( 2 ) for providing a rotary motion;    a motor casing surrounding the electrical motor, wherein the volume changeable free chamber ( 19 ) is connected to the atmosphere through the motor casing ( 31 ) surrounding the electric motor ( 2 );    a mechanical drive ( 3 ) connected to the electrical motor and to the piston compressor ( 1 ) and for converting the rotating motion of the electric motor ( 2 ) into an oscillating linear motion and for transferring the oscillating linear motion onto the piston compressor ( 1 ).    
     
     
         10 . The piston compressor according to  claim 9  further comprising 
 an admission check valve ( 27 ) associated with the volume changeable free chamber ( 19 ), wherein the volume changeable free chamber ( 19 ) has a connection to the outer atmosphere through the admission check valve ( 27 ).  
 
     
     
         11 . The piston compressor according to  claim 9  further comprising 
 a suction chamber ( 23 ), wherein the low-pressure chamber ( 8 ) has the suction chamber ( 23 ) predisposed and wherein the suction chamber ( 23 ) is connected on the one hand to the low-pressure chamber ( 8 ) and on the other hand to the interior of the motor casing ( 31 ) and to the outer atmosphere.  
 
     
     
         12 . The piston compressor according to  claim 11  further comprising 
 an inlet opening ( 24 ) disposed at the suction chamber ( 23 ) and disposed outside of the dirt and water endangered region for safeguarding the kind of protection of the electrical motor ( 2 ).  
 
     
     
         13 . The piston compressor according to  claim 11  further comprising 
 a third casing opening ( 22 ) disposed at the motor casing ( 31 ) and disposed outside of the dirt and water endangered region for safeguarding the kind of protection of the electrical motor ( 2 ).  
 
     
     
         14 . A method for cooling of an electrical motor ( 2 ) for a piston compressor ( 1 ) comprising 
 employing a low pressure piston having a first size;    employing a high pressure piston having a second size different from the first size;    solidly connecting thee low-pressure piston to the high pressure piston with a common piston rod ( 12 ) forming a bypass channel ( 17 );    surrounding the low-pressure piston, the high pressure piston, and the common piston rod with an inner chamber ( 5 ) for forming a volume changeable free chamber ( 19 ) between the low pressure piston and the high pressure piston;    suctioning air into the volume changeable free chamber during an increase in volume of the volume changeable free chamber, wherein the low pressure piston, the high pressure piston, the common piston rod ( 12 ) and the inner chamber ( 5 ) form a piston compressor ( 1 );    ejecting air from the free chamber during a decrease in volume of the volume changeable free chamber, wherein either the air suctioned or the air ejected by the volume changeable free chamber ( 19 ) is employed as a cooling agent for an electric motor ( 2 ).    
     
     
         15 . The method according to  claim 14  further comprising 
 moving air by the piston compressor ( 1 );  
 alternatingly suctioned the air in from the atmosphere through the inner chamber of the electric motor ( 2 ) and removing the air into the atmosphere.  
 
     
     
         16 . The method according to  claim 14  further comprising 
 moving the air moved by the piston compressor ( 1 );  
 separately suctioning air in from the atmosphere and removing air into the atmosphere through an inner chamber of a motor casing ( 31 ).  
 
     
     
         17 . The method according to  claim 16  further comprising 
 moving the air by the piston compressor ( 1 );  
 leading simultaneously air into the low-pressure chamber ( 8 ) of the compressor ( 1 ) through the inner chamber of the motor casing ( 31 ).  
 
     
     
         18 . A piston compressor apparatus comprising 
 a movable low pressure piston forming a volume changeable low-pressure chamber ( 8 );    a movable high-pressure piston ( 11 ) forming volume changeable high-pressure chamber ( 10 );    a bypass channel ( 17 ) connecting the low-pressure chamber ( 8 ) and the high pressure chamber ( 10 ) and wherein the low-pressure piston ( 9 ) and the high-pressure piston ( 11 ) are formed as a single piece;    a volume changeable free chamber ( 19 ) disposed between the low-pressure piston ( 9 ) and the high-pressure piston ( 11 ), wherein the volume changeable free chamber ( 19 ) changes volume together with a motion of the low-pressure piston and of the high pressure piston, and wherein the movable low pressure piston ( 9 ), the movable high-pressure piston ( 11 ), the bypass channel ( 17 ) and the volume changeable free chamber ( 19 ) form a piston compressor ( 1 );    an electrical motor ( 2 ) providing a rotary motion;    a motor casing surrounding the electrical motor, wherein the volume changeable free chamber ( 19 ) is connected to the atmosphere through the motor casing ( 31 ) surrounding the electric motor ( 2 );    a mechanical drive ( 3 ) connected to the electrical motor and to the piston compressor ( 1 ) and for converting the rotating motion of the electric motor ( 2 ) into an oscillating linear motion and for transfering the oscillating linear motion onto the piston compressor ( 1 ).    
     
     
         19 . The piston compressor according to  claim 18  further comprising 
 a check valve associated with the volume changeable free chamber ( 19 ), wherein the volume changeable free chamber ( 19 ) has a connection to the outer atmosphere through the check valve.  
 
     
     
         20 . The piston compressor according to  claim 19  further comprising 
 an additional check valve associated with the volume changeable free chamber ( 19 ), wherein the additional check valve is associated with the volume changeable free chamber and controls air flow through the motor casing, wherein the additional check valve is of an admission type when the check valve is of an exhaust type and wherein the additional check valve is of an exhaust type when the check valve is of an admission type.