Compressor System with Controlled Lubricant Reclaim

Abstract

A compressor system with controlled lubricant reclaim includes a compressor circuit having a compressor, a condenser, and an evaporator connected by refrigerant flow line; a lubricant circuit for circulating lubricant to the compressor; a reclaim vaporizer adapted to heat a refrigerant-lubricant mixture from the evaporator whereby the mixture is heated and lubricant and refrigerant are separated to provide reclaimed lubricant to the lubricant circuit and reclaimed refrigerant to the compressor circuit; and a control unit adapted to control flow of the mixture from the evaporator to the reclaim vaporizer based upon temperature of the mixture from the evaporator and temperature of reclaimed lubricant leaving the reclaim evaporator. Methods are also provided.

1 . A compressor system with controlled lubricant reclaim, comprising:
 a compressor circuit comprising a compressor, a condenser, and an evaporator connected by refrigerant flow line;   a lubricant circuit for circulating lubricant to the compressor;   a reclaim vaporizer adapted to heat a refrigerant-lubricant mixture from the evaporator whereby the mixture is heated and lubricant and refrigerant are separated to provide reclaimed lubricant to the lubricant circuit and reclaimed refrigerant to the compressor circuit; and   a control unit adapted to control flow of the mixture from the evaporator to the reclaim vaporizer based upon temperature of the mixture from the evaporator and temperature of reclaimed lubricant leaving the reclaim evaporator.   
   
   
       2 . The system of  claim 1 , wherein the control unit comprises a valve positioned along a discharge line for conveying the mixture from the evaporator to the reclaim vaporizer. 
   
   
       3 . The system of  claim 2 , wherein the control unit is adapted to operate the valve to control flow rate of the mixture to the reclaim evaporator so as to maintain a temperature difference between the reclaimed lubricant and the mixture within a preselected range. 
   
   
       4 . The system of  claim 1 , wherein the control unit is adapted to control flow rate of the mixture to the reclaim evaporator so as to maintain a temperature difference between the reclaimed lubricant and the mixture within a preselected range. 
   
   
       5 . The system of  claim 1 , wherein the reclaim vaporizer is communicated with discharge gas from the compressor to heat the mixture. 
   
   
       6 . The system of  claim 5 , further comprising a supplemental heater for providing additional heat to the mixture in the reclaim vaporizer. 
   
   
       7 . The system of  claim 1 , wherein the compressor is a screw compressor. 
   
   
       8 . A method for controlling reclaim of lubricant in a compressor system, comprising the steps of:
 operating a compressor circuit comprising a compressor, a condenser and an evaporator and a lubricant circuit for circulating lubricant to the compressor so as to provide a refrigerant-lubricant mixture leaving the evaporator;   exposing the mixture to heat in a reclaim vaporizer so as to provide reclaimed lubricant to the lubricant circuit and reclaimed refrigerant to the compressor circuit; and   controlling flow rate of the mixture to the reclaim vaporizer based upon temperature of the mixture leaving the evaporator and temperature of the reclaimed lubricant leaving the reclaim vaporizer.   
   
   
       9 . The method of  claim 8 , wherein the controlling step comprises sensing the temperature of the mixture and the reclaimed lubricant, and controlling flow of the mixture to the reclaim vaporizer to maintain a temperature difference between reclaimed lubricant temperature and mixture temperature within a preselected range. 
   
   
       10 . A method for controlling reclaim of lubricant in a compressor system, comprising the steps of:
 operating a compressor circuit comprising a compressor, a condenser and an evaporator and a lubricant circuit for circulating lubricant to the compressor so as to provide a refrigerant-lubricant mixture leaving the evaporator;   exposing the mixture to heat in a reclaim vaporizer so as to provide reclaimed lubricant to the lubricant circuit and reclaimed refrigerant to the compressor circuit;   sensing a parameter indicative of reclaimed lubricant viscosity; and   controlling rate of exposure of the mixture to heat based upon the parameter.   
   
   
       11 . The method of  claim 10 , wherein the controlling step comprises at least one of controlling flow of mixture to the reclaim vaporizer, controlling amount of heat applied to the mixture and combinations thereof, so as to maintain reclaimed lubricant viscosity within a preselected range.