A working fluid extraction system for a displacement machine and a method of operating the system

Abstract

A working fluid extraction system is for a displacement machine for removing a condensable working fluid from a working fluid/lubricant mix in an interior volume of the displacement machine separate from a working chamber of the displacement machine. The system has a condenser operatively connected to the interior volume, wherein the condenser is settable to a lower temperature and/or pressure than the temperature and/or pressure of the interior volume such that working fluid is drawn from the interior volume to the condenser in use.

1 .- 25 . (cancelled) 
     
     
         26 . A working fluid extraction system for a displacement machine for removing a condensable working fluid from a working fluid/lubricant mix in an interior volume of the displacement machine separate from a working chamber of the displacement machine, wherein the system comprising a condenser operatively connected to the interior volume, wherein the condenser is settable to a lower temperature and/or pressure than the temperature and/or pressure of the interior volume such that working fluid is drawn from the interior volume to the condenser in use. 
     
     
         27 . The working fluid extraction system of  claim 26 , further comprising a first fluid pump configured to pump working fluid from the interior volume to the condenser, to assist in the draw of working fluid from the working fluid/lubricant mix in the interior volume to the condenser. 
     
     
         28 . The working fluid extraction system of  claim 26 , further comprising a condensed fluid pump configured to pump condensed working fluid from the condenser to a working fluid circuit of a thermal machine comprising the displacement machine, such that the working fluid drawn from the working fluid/lubricant mix in the interior volume can be reintroduced into a working chamber of the displacement machine. 
     
     
         29 . The working fluid extraction system of  claim 28 , further comprising a non-return valve arranged in fluid communication with the condensed fluid pump and the working fluid circuit, and configured to allow fluid to be pumped from the condensed fluid pump into the working fluid circuit, but not from the working fluid circuit to the condensed fluid pump. 
     
     
         30 . The working fluid extraction system of  claim 29 , wherein the non-return valve is configured to deliver fluid to a pressure reducing valve in the thermal machine. 
     
     
         31 . The working fluid extraction system of  claim 26 , further comprising a vent connected to the interior volume, and configured to allow excess working fluid to be expelled from the interior volume wherein the vent is a non-return valve. 
     
     
         32 . The working fluid extraction system of  claim 31 , wherein the vent is fluidly connected to a working fluid circuit of a thermal machine comprising the displacement machine, such that expelled working fluid can be reintroduced into a working chamber of the displacement machine. 
     
     
         33 . The working fluid extraction system of  claim 26 , wherein the displacement machine is a compressor. 
     
     
         34 . The working fluid extraction system of  claim 26 , further comprising a fluid separator system for separating the condensable working fluid from the lubricant in the interior volume, the fluid separator system comprising:
 a fluid separator chamber;   a fluid separator inlet operatively connected to the interior volume and configured to allow fluid communication between the interior volume and the fluid separator chamber;   a fluid separator shielding member arranged at the fluid separator inlet and configured to restrict a quantity of working fluid/lubricant mix entering the fluid separator inlet;   
       wherein the fluid separator chamber is configured in use to provide a deceleration of the working fluid/lubricant mix entering the fluid separator chamber from the fluid separator inlet, such that, in use, the working fluid/lubricant mix entering the fluid separator chamber is decelerated, thereby separating at least some working fluid from the lubricant. 
     
     
         35 . The working fluid extraction system of  claim 34 , wherein the fluid separator system further comprises a fluid separator channel fluidly connected to the fluid separator chamber, such that in use separated working fluid can be evacuated from the fluid separator chamber through the fluid separator channel wherein the condenser is operatively connected to the interior volume via the fluid separator system, such that in use, working fluid can be separated from the working fluid/lubricant mix by the fluid separator chamber, and delivered to the condenser by the fluid separator channel. 
     
     
         36 . A thermal machine comprising:
 a displacement machine comprising a working chamber and an interior volume;   an evaporator;   a pressure reducing valve;   a recuperator;   a receiver;   a filter;   a first condenser;   a condensable working fluid;   a shut-off valve located between the recuperator and the displacement machine; and   the working fluid extraction system according to  claim 26  wherein the condenser of the working fluid extraction system is a second condenser.   
     
     
         37 . The thermal machine of  claim 36 , wherein the displacement machine is a compressor. 
     
     
         38 . The thermal machine of  claim 36 , further comprising a fluid separator system for separating the condensable working fluid from the lubricant in the interior volume, the fluid separator system comprising:
 a fluid separator chamber;   a fluid separator inlet operatively connected to the interior volume and configured to allow fluid communication between the interior volume and the fluid separator chamber;   a fluid separator shielding member arranged at the fluid separator inlet and configured to restrict a quantity of working fluid/lubricant mix entering the fluid separator inlet;   
       wherein the fluid separator chamber is configured in use to provide a deceleration of fluid entering the fluid separator chamber from the fluid separator inlet, such that, in use, the working fluid/lubricant mix entering the fluid separator chamber is decelerated, thereby separating at least some working fluid from the lubricant. 
     
     
         39 . The thermal machine of  claim 38 , wherein the fluid separator system further comprises a fluid separator channel fluidly connected to the fluid separator chamber, such that in use separated working fluid can be evacuated from the fluid separator chamber through the fluid separator channel, wherein the second condenser is operatively connected to the interior volume via the fluid separator system, such that in use, working fluid can be separated from the working fluid/lubricant mix by the fluid separator chamber, and delivered to the second condenser by the fluid separator channel. 
     
     
         40 . A method of extracting working fluid from a working fluid/lubricant mix in an interior volume of a displacement machine, the method comprising the steps of:
 a. providing a working fluid extraction system according to  claim 26 ;   b. and one of the steps of:
 i. setting the temperature of the condenser to less than the temperature of the interior volume; or 
 ii. setting the pressure of the condenser to less than pressure of the interior volume; or 
 iii. setting the temperature of the condenser to less than the temperature of the interior volume and setting the pressure of the condenser to less than the pressure of the interior volume, 
   
       such that working fluid in the interior volume is drawn to the condenser. 
     
     
         41 . A method of extracting working fluid from a working fluid/lubricant mix in an interior volume of a displacement machine, the method comprising the steps of:
 c. providing a working fluid extraction system according to  claim 34 ;   d. separating the working fluid from the working fluid/lubricant mix in the fluid separator system;   e. and one of the steps of:
 i. setting the temperature of the condenser to less than the temperature of the interior volume; or 
 ii. setting the pressure of the condenser to less than pressure of the interior volume; or 
 iii. setting the temperature of the condenser to less than the temperature of the interior volume and setting the pressure of the condenser to less than the pressure of the interior volume, 
   
       such that separated working fluid is drawn to the condenser. 
     
     
         42 . A fluid separator system for separating a condensable working fluid from a lubricant in a working fluid/lubricant mix, the fluid separator system comprising:
 a fluid separator chamber;   a fluid separator inlet;   a fluid separator shielding member arranged at the fluid separator inlet and configured to restrict a quantity of working fluid/lubricant mix entering the fluid separator inlet;   
       wherein the fluid separator chamber is configured in use to provide a deceleration of fluid entering the fluid separator chamber from the fluid separator inlet, such that, in use, the working fluid/lubricant mix entering the fluid separator chamber is decelerated, thereby separating at least some of the working fluid from the lubricant. 
     
     
         43 . The fluid separator system of  claim 42 , further comprises a fluid separator channel fluidly connected to the fluid separator chamber, such that in use separated working fluid can be evacuated from the fluid separator chamber through the fluid separator channel. 
     
     
         44 . A method of separating a working fluid from a working fluid/lubricant mix the method comprising the steps of:
 f. providing a fluid separator system according to  claim 42 ;   g. passing a working fluid/lubricant mix past the fluid separator shielding member, thereby delivering a restricted quantity of working fluid/lubricant mix to the fluid separator inlet;   h. passing the working fluid/lubricant mix through the fluid separator inlet to the fluid separator chamber;   i. decelerating the working fluid/lubricant mix in the fluid separator chamber, thereby separating at least some of the working fluid from the working fluid/lubricant mix.   
     
     
         45 . The method of  claim 44 , further comprising a step of:
 j. evacuating separated working fluid from the fluid separator chamber through a fluid separator channel.