Compressor shaft seal

Abstract

A seal for a compressor for sealing a shaft comprises a first seal part with a sealing edge which is provided on a circular cylindrical surface along a line which deviates from a circular shape and which is closed in itself in the peripheral direction for adjoining and sealing the shaft, and a second seal part with a sealing section which is intended to adjoin the shaft and which is hollowly cylindrical when it adjoins properly with the inside surface which comprises a return structure for a fluid.

1 . A compressor apparatus comprising:
 a housing containing a lubricant and a coolant;   a rotatable shaft penetrating the housing;   a seal adjoining the shaft to seal against leakage of the lubricant and the coolant so that the lubricant and the coolant do not leak to outside the housing, the seal comprising:   a first seal part possessing a cylindrical sealing edge adjoining the seal and seal the shaft, the sealing edge extending along a line which deviates from a circular shape and which is closed in itself in a peripheral direction, the line along which the sealing edge extends is wavy, comprising several arcs; and   a second seal part with a sealing section which is adapted to adjoin the shaft and which is hollowly cylindrical when the sealing section adjoins properly with an outside surface of the shaft, the sealing section comprising a return structure for returning a fluid, the sealing section configured to extend along the outside surface of the shaft between the first seal part and the shaft when the sealing section properly adjoins the outside surface of the shaft.   
     
     
         2 . The compressor as claimed in  claim 1 , wherein the return structure is configured as a screw thread. 
     
     
         3 . The compressor as claimed in  claim 1 , wherein the return structure comprises at least three grooves spaced apart in a peripheral direction. 
     
     
         4 . The compressor as claimed in  claim 3 , wherein when the sealing section properly adjoins the shaft, at least one of the grooves extends as an arc-shaped groove. 
     
     
         5 . The compressor as claimed in  claim 4 , wherein the arc-shaped groove possesses a gradient increasing in absolute value in a direction toward the sealing edge. 
     
     
         6 . The compressor as claimed in  claim 3 , wherein at least one of the grooves opens to a side of the sealing edge. 
     
     
         7 . The compressor as claimed in  claim 3 , wherein at least two of the grooves cross one another. 
     
     
         8 . The compressor as claimed in  claim 1 , wherein in an axial end region of the sealing section opposite the sealing edge, the return structure comprises a groove which extends peripherally as a circular ring groove. 
     
     
         9 . The compressor as claimed in  claim 8 , wherein the return structure further comprises at least one additional groove which starts from the circular ring groove. 
     
     
         10 . The compressor as claimed in one of  claim 1 , wherein the first seal part is made from a first material and the second seal part is made from a second material different from the material forming the first seal part. 
     
     
         11 . The compressor as claimed in  claim 10 , wherein the second material is polytetrafluorethylene (PTFE). 
     
     
         12 . The compressor as claimed in  claim 11 , wherein the first material is an elastomer material. 
     
     
         13 . The compressor as claimed in  claim 1 , wherein the second seal part is joined to the first seal part chemically. 
     
     
         14 . The compressor as claimed in  claim 1 , further comprising a stiffening part, wherein the first seal part is vulcanized to the stiffening part. 
     
     
         15 . The compressor as claimed in  claim 14 , wherein the stiffening part is made from a metal. 
     
     
         16 . The compressor as claimed in  claim 1 , further comprising a stiffening part, wherein the second seal part comprises a radially extending first surface region connected to at least one of the first seal part and the stiffening part, and a radially extending second surface region of the second seal part opposite the first surface region and free of contact with the stiffening part. 
     
     
         17 . The compressor as claimed in  claim 1 , wherein an axial end region of the sealing edge of the first seal part and the sealing section of the second seal part are constructed such that the sealing section extends axially and is free of collision with the sealing edge when the seal is properly installed. 
     
     
         18 . The compressor as claimed in  claim 1 , further comprising a third seal part which is adapted to surround and seal the shaft. 
     
     
         19 . The compressor as claimed in  claim 18 , wherein the third seal part comprises a gas diffusion-capable fabric that is nonwoven. 
     
     
         20 . The compressor as claimed in  claim 1 , wherein the seal comprises an outer hollow cylindrical section, a perforated disk-like section which is connected to an axial end of the outer hollow cylindrical section and continues towards inside from the outer hollow cylindrical section, and an inner hollow cylindrical section connected to an inside edge of the perforated-disk like section and extending away from the outer hollow cylindrical section. 
     
     
         21 . The compressor as claimed in  claim 20 , wherein the outer hollow cylindrical section comprises a hollow cylindrical region of a stiffening part whose outer surface is connected to a hollow-cylindrical region of the first seal part. 
     
     
         22 . The compressor as claimed in  claim 20 , wherein the perforated-disk like section comprises a perforated-disk like region of a stiffening part which is surrounded completely by the first seal part. 
     
     
         23 . The compressor as claimed in  claim 20 , wherein in the perforated-disk like section, the second seal part is connected to the first seal part. 
     
     
         24 . The compressor as claimed in  claim 20 , wherein the inner hollow cylindrical section comprises a hollow cylindrical region of a stiffening part which is completely surrounded by the first seal part. 
     
     
         25 . The compressor as claimed in  claim 20 , wherein in the inner hollow cylindrical section the first seal part forms the sealing edge. 
     
     
         26 . The compressor as claimed in  claim 1 , wherein the return structure is configured as at least one curvalinear groove. 
     
     
         27 . The compressor as claimed in  claim 26 , wherein the at least one curvalinear groove is arc-shaped. 
     
     
         28 . The compressor as claimed in  claim 1 , wherein the first seal part includes a conically shaped portion having a radially outward surface, the radially outward surface extending from a location of the first seal part which axially overlaps the sealing section of the second seal part to a free end of the first seal part, and the radially outward surface being linear over the entire length of the conically shaped portion.