Condenser liquid delivery regulator for a refrigerated dryer having condensate harvester

Abstract

An air compressor system useful for supplying a stream of compressed air for an end user is disclosed which includes a refrigerated dryer useful to remove moisture and harvest it from the compressed air. The refrigerated dryer includes an evaporator and a condenser, where the evaporator is useful to produce the moisture from the compressed air. The air compressor system includes an expansion tank which collects the harvested moisture from the evaporator. The expansion tank can provide liquid to a pump that conveys the liquid to a condenser of the dryer. The refrigerated dryer includes a temperature sensor that detects a temperature of refrigerated fluid associated with the condenser and regulates the pump to supply liquid to the condenser to assist in heat rejection.

What is claimed is: 
     
         1 . An apparatus comprising:
 a gas compressor system operable to produce a wet compressed gas and having a compressor outlet in fluid communication with a refrigerated dryer, the refrigerated dryer including a condenser for cooling a refrigeration fluid and a heat exchanger that exchanges heat from the wet compressed gas with a refrigeration fluid of the refrigerated dryer to cool and remove moisture from the wet compressed gas while heating the refrigeration fluid, the gas compressor system also including:
 an expansion tank structured to contain water, the expansion tank oriented to receive a condensate produced from the heat exchanger as it removes moisture from the wet compressed gas; 
 a temperature sensor configured to sense temperature of a refrigeration fluid flowing from a condenser of the refrigerated dryer to the heat exchanger; and 
 a pump in fluid communication with the expansion tank and configured to deliver water from the expansion tank to the condenser, the pump regulated by the gas compressor system when the temperature sensor detects a temperature of the refrigeration fluid at or above a predetermined temperature. 
   
     
     
         2 . The apparatus of  claim 1 , wherein regulation of the pump includes operating the pump at different speeds to provide variable flow rate of water from the expansion tank to the condenser of the refrigerated dryer. 
     
     
         3 . The apparatus of  claim 2 , wherein the expansion tank further includes a low water level sensor. 
     
     
         4 . The apparatus of  claim 3 , wherein the compressor system is structured to trigger a valve disposed between the expansion tank and a utility water supplier, the valve configured to permit introduction of water into the expansion tank from a continuous supply of water from a utility water supplier in the event that the low water level sensor detects a low water level. 
     
     
         5 . The apparatus of  claim 4 , wherein the valve is held open for a period of time in which a water level rises within the tank to a level below a pre-determined water level. 
     
     
         6 . The apparatus of  claim 4 , wherein the expansion tank further includes a high water level sensor. 
     
     
         7 . The apparatus of  claim 6 , wherein the valve is held open until the water level rises within the tank to the high water level sensor. 
     
     
         8 . The apparatus of  claim 4 , and which further includes an overflow valve structured to release water from the expansion tank when the water level reaches a pre-determined overflow condition. 
     
     
         9 . An apparatus comprising:
 a compressor system including gas compressor structured to produce a flow of wet compressed gas and a refrigerated dryer having a closed refrigeration cycle, wherein the closed refrigeration cycle includes:
 a compressor for pressurizing a refrigeration fluid and conveying the refrigeration fluid throughout the closed refrigeration cycle; 
 a condenser for cooling the refrigeration fluid after has been compressed by the compressor; and 
 an evaporator for receiving the refrigeration fluid from the condenser and exchanging heat with a wet compressed gas flow stream produced by the gas compressor; 
   wherein the compressor system also includes:
 an expansion tank configured to receive condensate produced from the evaporator, the condensate extracted from the wet compressed gas flow stream when it has been cooled by action of the evaporator; 
 a pump in fluid communication with the expansion tank and configured to provide water from the expansion tank to the condenser; and 
 a temperature sensor configured to sense temperature of the refrigeration fluid on an outlet side of the condenser; and 
   wherein the compressor system triggers the pump to provide water from the expansion tank to the condenser when a temperature signal provided by the temperature sensor exceeds a threshold indicating an elevated temperature in the refrigeration fluid on the outlet side of the condenser.   
     
     
         10 . The apparatus of  claim 9 , wherein the expansion tank is coupled with a conduit structured to flow water from a utility water source that supplies a continuous flow of water. 
     
     
         11 . The apparatus of  claim 10 , wherein the expansion tank includes a low water level sensor and the conduit includes a valve structured to open and close the conduit. 
     
     
         12 . The apparatus of  claim 11 , wherein the valve is commanded by the compressor system to open and flow water to the expansion tank when the low water level sensor indicates a low water level in the expansion tank. 
     
     
         13 . The apparatus of  claim 12 , wherein the expansion tank includes a high water level sensor, and wherein an overflow valve is coupled with the expansion tank to vent excess water when the high water level detects water. 
     
     
         14 . The apparatus of  claim 13 , wherein the compressor system is structured to command the pump to flow water for a time period shorter than a period required to overflow the expansion tank. 
     
     
         15 . The apparatus of  claim 14 , wherein the compressor system controls the pump between a number of pre-determined pump speeds. 
     
     
         16 . A method comprising:
 compressing a gas containing water vapor to form a wet compressed gas;   flowing the wet compressed gas through an evaporator heat exchanger to extract water condensate from the wet compressed gas, the evaporator heat exchanger part of a refrigerated air dryer;   harvesting the water condensate in an expansion tank; and   variably regulating a pump to provide a demand-based flow rate of water from the expansion tank to a condenser of the refrigerated dryer based upon a temperature of refrigeration fluid of the condenser, the demand-based flow rate of water a function of the temperature of the refrigeration fluid of the condenser.   
     
     
         17 . The method of  claim 16 , which further includes sensing a low water level in the expansion tank. 
     
     
         18 . The method of  claim 17 , which further includes flowing water from a continuous source of utility water in response to the sensing a low water level. 
     
     
         19 . The method of  claim 18 , which further includes closing a valve to stop the flowing of water from the continuous source of utility water, and which further includes a high water level sensor. 
     
     
         20 . The method of  claim 19 , which further includes an overflow valve configured to vent water from the expansion tank when it receives a signal indicative of a high water level sensed by the high water level sensor.