Liquid refrigerant pumping system

Abstract

A lubricant supply system includes first and second tanks, each including an internal volume that is divided into a first portion and a second portion. The first portion of the internal volume of the first tank and the first portion of the internal volume of the second tank are configured to alternate supplying a liquid refrigerant to a machine. A pump is in fluid communication with the second portion of the internal volume of the first tank and the second portion of the internal volume of the second tank. The pump is configured to vary a pressure of a gas in the second portion of the internal volume of the first tank and the second portion of the internal volume of the second tank.

What is claimed is: 
     
         1 . A lubricant supply system, comprising:
 a first tank defining an internal volume that is divided into a first portion and a second portion;   a second tank defining an internal volume that is divided into a first portion and a second portion, wherein the first portion of the internal volume of the first tank and the first portion of the internal volume of the second tank are configured to alternate supplying a liquid refrigerant to a machine; and   a pump in fluid communication with the second portion of the internal volume of the first tank and the second portion of the internal volume of the second tank, wherein the pump is configured to vary a pressure of a gas in the second portion of the internal volume of the first tank and the second portion of the internal volume of the second tank.   
     
     
         2 . The lubricant supply system of  claim 1 , wherein the first portion of the internal volume of the first tank and the first portion of the internal volume of the second tank are configured to be in fluid communication with a refrigeration chiller and to receive the liquid refrigerant therefrom. 
     
     
         3 . The lubricant supply system of  claim 2 , wherein the pump is configured to transfer at least a portion of the gas from the second portion of the internal volume of the first tank to the second portion of the internal volume of the second tank, thereby generating a pressure differential that draws the liquid refrigerant from the refrigeration chiller into the first portion of the internal volume of the first tank. 
     
     
         4 . The lubricant supply system of  claim 2 , wherein the pump is configured to transfer at least a portion of the gas back and forth between the second portion of the internal volume of the first tank and the second portion of the internal volume of the second tank. 
     
     
         5 . The lubricant supply system of  claim 4 , wherein the first portion of the internal volume of the first tank and the first portion of the internal volume of the first tank are configured to alternate drawing the liquid refrigerant from the refrigeration chiller based on operation of the pump. 
     
     
         6 . The lubricant supply system of  claim 1 , wherein the pump comprises:
 a first pump in fluid communication with the second portion of the internal volume of the first tank; and   a second pump in fluid communication with the second portion of the internal volume of the second tank.   
     
     
         7 . The lubricant supply system of  claim 1 , wherein the first and second portions of the internal volume of the first tank are separated by a divider, and wherein the divider comprises a diaphragm, a piston, or a bladder. 
     
     
         8 . A lubricant supply system, comprising:
 a first tank defining an internal volume that is divided into a first portion and a second portion;   a second tank defining an internal volume that is divided into a first portion and a second portion;   a refrigeration chiller including an evaporator and a condenser;   a valve in fluid communication with the first portion of the internal volume of the first tank, the evaporator, and the condenser, wherein the valve provides a path of fluid communication from the evaporator to the first portion of the internal volume of the first tank when the valve is in a first position, and wherein the valve provides a path of fluid communication from the condenser to the first portion of the internal volume of the first tank when the valve is in a second position; and   a pump in fluid communication with the second portion of the internal volume of the first tank and the second portion of the internal volume of the second tank, wherein the pump is configured to vary a pressure of a gas in the second portion of the internal volume of the first tank and the second portion of the internal volume of the second tank.   
     
     
         9 . The lubricant supply system of  claim 8 , wherein the pump is configured to simultaneously increase the pressure of the gas in the second portion of the internal volume of the first tank and decrease the pressure of the gas in the second portion of the internal volume of the second tank. 
     
     
         10 . The lubricant supply system of  claim 9 , wherein the increased pressure in the second portion of the internal volume of the first tank causes a liquid refrigerant to flow from the first portion of the internal volume of the first tank to one or more bearings in a compressor in the refrigeration chiller. 
     
     
         11 . The lubricant supply system of  claim 10 , wherein the decreased pressure in the second portion of the internal volume of the second tank causes additional liquid refrigerant to be drawn into the first portion of the internal volume of the second tank from the evaporator or the condenser. 
     
     
         12 . The lubricant supply system of  claim 11 , wherein the pump is configured to transfer at least a portion of the gas back and forth between the second portion of the internal volume of the first tank and the second portion of the internal volume of the second tank. 
     
     
         13 . The lubricant supply system of  claim 11 , wherein the pump comprises:
 a first pump in fluid communication with the second portion of the internal volume of the first tank; and   a second pump in fluid communication with the second portion of the internal volume of the second tank.   
     
     
         14 . A method for supplying a liquid refrigerant to a machine, comprising:
 causing a pressure of a gas in a first tank to decrease, which draws a liquid refrigerant into the first tank from a refrigeration chiller;   causing a pressure of a gas in second first tank to decrease, which draws additional liquid refrigerant into the second tank from the refrigeration chiller; and   causing the pressure of the gas in the first tank to increase simultaneously with the pressure of the gas in the second tank decreasing, which causes the liquid refrigerant to flow from the first tank to a bearing in a compressor in the refrigeration chiller.   
     
     
         15 . The method of  claim 14 , further comprising causing the pressure of the gas in the second tank to increase simultaneously with the pressure of the gas in the first tank decreasing, which causes the additional liquid refrigerant to flow from the second tank to the bearing in the compressor. 
     
     
         16 . The method of  claim 14 , wherein a pump causes the pressure of the gas in the first tank to increase simultaneously with the pressure of the gas in the second tank decreasing by transferring at least a portion of the gas in the first tank to the second tank. 
     
     
         17 . The method of  claim 14 , further comprising actuating a valve from a first position to a second position, wherein the liquid refrigerant flows from an evaporator of the refrigeration chiller, through the valve, and to the first tank when the valve is in the first position, and wherein the liquid refrigerant flows from a condenser of the refrigeration chiller, through the valve, and to the first tank when the valve is in the second position. 
     
     
         18 . The method of  claim 14 , wherein the first and second tanks alternate supplying the liquid refrigerant and the additional liquid refrigerant to the bearing in the compressor. 
     
     
         19 . The method of  claim 14 , further comprising closing a shut-off valve positioned proximate to an opening in the first tank through which the liquid refrigerant flows before the pressure of the gas in the first tank decreases. 
     
     
         20 . The method of  claim 14 , wherein the gas in the first tank and the liquid refrigerant in the first tank are separated by a divider, and wherein the divider comprises a diaphragm, a piston, or a bladder.