Oil-free lubrication centrifugal refrigerant compressor and lubrication method thereof

Abstract

An oil-free lubrication centrifugal refrigerant compressor for compressing low-pressure refrigerant into high-pressure refrigerant, includes: a housing; a refrigerant pathway; a compression module; a radial bearing; a first conducting member, collecting troughs and a first exhaust member. Therein, the compression module has a rotating shaft, a compressing member and a driving member; the radial bearing is rotatably disposed around the rotating shaft; the first conducting member conducts lubricating refrigerant fluid to the outer surface of the radial bearing and the inner surface of the rotating shaft so as to provide appropriate lubrication to the radial bearing and the rotating shaft when the driving member drives the rotating shaft to rotate and activate the compressing member to compress low pressure refrigerant into high pressure refrigerant; and the first exhaust member exhausts the lubricating refrigerant fluid, thereby solving the problem of contamination caused by using oil lubricants for compressors as encountered in prior techniques.

1 . An oil-free lubrication centrifugal refrigerant compressor for compressing low-pressure refrigerant into high-pressure refrigerant, comprising:
 a housing;   a refrigerant pathway communicating with the housing and having a first pathway for inlet of low-pressure refrigerant and a second pathway for outlet of high-pressure refrigerant;   a compression module disposed inside the housing and having a rotating shaft, a compressing member, a driving member that are connected with the rotating shaft, and a fixed outer wall encloses an outside of the rotating shaft, wherein the driving member drives the rotating shaft to rotate so as to activate the compressing member to compress the lower-pressure refrigerant into the high-pressure refrigerant;   a radial bearing positioned between the fixed outer wall and the rotating shaft and rotatably disposed around the rotating shaft, wherein micro-spaces exist between an inner surface of the radial bearing and a surface of the rotating shaft and between an outer surface of the radial bearing and the fixed outer wall, and the radial bearing being further formed with at least a through hole communicating the outer surface thereof with the surface of the rotating shaft;   a first conducting member disposed inside the housing and communicated with the outer surface of the radial bearing through the fixed outer wall so as to conduct lubricating refrigerant fluid to the outer surface of the radial bearing and further to the inner surface of the rotating shaft through the through hole of the radial bearing, thereby providing lubrication between the radial bearing and the fixed outer wall and between the radial bearing and the rotating shaft during operation of the compression module;   a plurality of collecting troughs disposed at two ends of the radial bearing, respectively, and communicated with the micro-spaces for collecting the lubricating refrigerant fluid conducted to the outer and inner surfaces of the radial bearing and the rotating shaft through the first conducting member; and   a first exhaust member communicated with the collecting troughs for exhausting the lubricating refrigerant fluid from the collecting troughs.   
     
     
         2 . The compressor of  claim 1 , further comprising an axial bearing disposed between one end of the rotating shaft of the compression module and the fixed outer wall, wherein the first conducting member is further communicated to surfaces of the axial bearing for conducting the lubricating refrigerant fluid to surfaces of the axial bearing so as to provide lubrication between the axial bearing and the rotating shaft and between the axial bearing and the fixed outer wall during operation of the compression module, and the collecting troughs are further disposed around a periphery of the axial bearing so as to collect the lubricating refrigerant fluid conducted to the surfaces of the axial bearing through the first conducting member. 
     
     
         3 . The compressor of  claim 1 , wherein one end of the first conducting member is connected with a condenser disposed at an outside of the housing, and one end of the first exhaust member is connected with an evaporator or an economizer disposed at the outside of the housing. 
     
     
         4 . The compressor of  claim 1 , further comprising a second conducting member and a second exhaust member connected with the driving member of the compression module, wherein the second conducting member conducts cooling fluid to the driving member and the second exhaust member exhausts the cooling fluid from the driving member. 
     
     
         5 . The compressor of  claim 4 , wherein one end of the second conducting member is connected with a condenser disposed at an outside of the housing, and one end of the second exhaust member is connected with an evaporator or an economizer disposed at the outside of the housing. 
     
     
         6 . The compressor of  claim 1 , further comprising a pressure storage device connected with the first conducting member for storing and pressurizing the lubricating refrigerant fluid so as to allow the lubricating refrigerant fluid to actively flow to the first conducting member by pressure when the compression module starts to operate. 
     
     
         7 . The compressor of  claim 1 , wherein the compression module further comprises a labyrinth seal ring disposed around the rotating shaft close to the compressing member so as to prevent leakage of the high-pressure refrigerant. 
     
     
         8 . The compressor of  claim 1 , wherein the collecting troughs at the two ends of the radial bearing communicate with the micro-spaces of the inner and outer surfaces of the radial bearing, and the micro-spaces range form 0.03 mm to 0.1 mm. 
     
     
         9 . The compressor of  claim 1 , wherein two through holes corresponding in position to each other are disposed in the radial bearing along each of a vertical axis and a horizontal axis that are orthogonal to an axial direction of the radial bearing. 
     
     
         10 . The compressor of  claim 1 , wherein two groups of through holes corresponding to each other are disposed in the radial bearing along an axial direction in parallel with the rotating shaft. 
     
     
         11 . A lubrication method of an oil-free lubrication centrifugal refrigerant compressor for lubricating a rotating shaft of the compressor and a fixed outer wall enclosing the rotating shaft, comprising the steps of:
 (1) rotatably disposing a radial bearing having at least one through hole around the rotating shaft between the fixed outer wall and the rotating shaft, wherein micro-spaces exist between an inner surface of the radial bearing and a surface of the rotating shaft and between an outer surface of the radial bearing and the fixed outer wall, and the through hole communicates the outer surface of the radial bearing with the surface of the rotating shaft; and   (2) conducting lubricating refrigerant fluid to the outer surface of the radial bearing through the fixed outer wall and further to the inner surface of the rotating shaft through the through hole of the radial bearing, thereby providing lubrication between the radial bearing and the fixed outer wall and between the radial bearing and the rotating shaft during operation of the rotating shaft.   
     
     
         12 . The method of  claim 11 , further comprising step (3) of disposing a plurality of collecting troughs to two ends of the radial bearing so as to collect the lubricating refrigerant fluid on the inner and outer surfaces of the radial bearing and the surface of the rotating shaft. 
     
     
         13 . The method of  claim 12 , further comprising step (4) of exhausting the lubricating refrigerant fluid from the collecting troughs. 
     
     
         14 . The method of  claim 13 , wherein step (4) further comprises exhausting the lubricating refrigerant fluid to an evaporator and/or an economizer. 
     
     
         15 . The method of  claim 11 , wherein step (2) further comprises: (2-1) providing a pressure storage device for storing and pressurizing the lubricating refrigerant fluid; and (2-2) delivering the lubricating refrigerant fluid to the surfaces of the radial bearing and the rotating shaft by pressure provided by the pressure storage device. 
     
     
         16 . The method of  claim 11 , wherein step (1) further comprises disposing an axial bearing between one end of the rotating shaft and the fixed outer wall; and step (2) further comprises conducting the lubricating refrigerant fluid to surfaces of the axial bearing through the fixed outer wall. 
     
     
         17 . The method of  claim 16 , further comprising step (3) of disposing a plurality of collecting troughs around a periphery of the axial bearing so as to collect the lubricating refrigerant fluid on the surfaces of the axial bearing. 
     
     
         18 . The method of  claim 17 , further comprising step (4) of exhausting the lubricating refrigerant fluid from the collecting troughs. 
     
     
         19 . The method of  claim 16 , wherein step (2) further comprises: (2-1) providing a pressure storage device for storing and pressurizing the lubricating refrigerant fluid; and (2-2) delivering the lubricating refrigerant fluid to the surfaces of the axial bearing by pressure provided by the pressure storage device. 
     
     
         20 . The method of  claim 18 , wherein step (4) further comprises exhausting the lubricating refrigerant fluid to an evaporator and/or an economizer.