Tank control and pump protection for air compressor system including a 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 include a low liquid level sensor useful to determine a low liquid level of condensate in the expansion tank. The low liquid level sensor can produce a signal indicating a low level of condensate which can be used to shut off a pump that pulls water from the expansion tank and provides it to the condenser of the refrigerated dryer.

What is claimed is: 
     
         1 . An apparatus comprising:
 A compressor system structured to compress a gas and provide a wet flow of gas and water vapor, the compressor system also including a refrigerated dryer structured to remove water vapor from the wet flow of gas and water vapor, the refrigerated dryer including an evaporator in fluid flow communication with the wet flow of gas and water vapor, the evaporator structured to condense the water vapor to form a condensate and provide the condensate to an expansion tank where the water vapor is harvested for later use with the condenser to cool the condenser, the expansion tank in fluid communication with a pump, the pump controlled by a switch to de-activate the pump if a level of condensate in the expansion tank is at a minimum level, and an overflow sensor structured to divert harvested condensate from the expansion tank when a level of condensate in the expansion tank reaches a maximum level.   
     
     
         2 . The apparatus of  claim 1 , wherein the overflow sensor is in electrical communication with a valve structured to vent condensate from the expansion tank. 
     
     
         3 . The apparatus of  claim 1 , wherein the expansion tank is a closed vessel, and which further includes a valve to regulate the diversion of condensate from the expansion tank. 
     
     
         4 . The apparatus of  claim 3 , wherein an overflow level is below a physical overflow level such that the pump will be activated to divert condensate from the expansion tank through the valve prior to an actual overflow event where condensate rises to a level that backflows into a passage. 
     
     
         5 . The apparatus of  claim 1 , wherein the overflow sensor is positioned to sense a level of condensate within the expansion tank that corresponds to an overflow condition. 
     
     
         6 . The apparatus of  claim 1 , which further includes a controller structured to receive an electrical signal from the overflow sensor, the controller having a module configured to activate the valve when the overflow sensor indicates a high condensate level. 
     
     
         7 . The apparatus of  claim 6 , wherein the overflow sensor is positioned to sense a level of condensate within the expansion tank that corresponds to an overflow condition that is below a physical overflow level of the expansion tank. 
     
     
         8 . An apparatus comprising:
 an air compressor system including:
 an air compressor operable to provide a flow of compressed air; 
 a refrigerated dryer in fluid communication with a compressed flow stream of the air compressor, the refrigerated dryer structured to remove moisture from the flow of compressed air, the refrigerated dryer including:
 a refrigeration compressor oriented to compress a refrigeration working fluid; 
 a condenser that cools a compressed refrigeration working fluid; 
 an evaporator that produces condensate from water vapor in the compressed air through cooling action of the evaporator; 
 
 wherein the air compressor system further includes:
 an expansion tank and pump configured to receive harvested condensate from the evaporator and provide the harvested condensate to the condenser, the tank including a low condensate level sensor and a high condensate level sensor; and 
 wherein the high condensate level sensor is in electrical communication with the pump such that detection of a high condensate level triggers the air compressor system to expel condensate from the expansion tank. 
 
   
     
     
         9 . The apparatus of  claim 8 , which further includes a controller in electrical communication with the high condensate level sensor and low condensate level sensor. 
     
     
         10 . The apparatus of  claim 9 , wherein the pump is prohibited through action of the controller from pumping if the low condensate level sensor indicates a low condensate level, which further includes a valve in fluid communication with the expansion tank which is activated by the controller when diverting condensate from the expansion tank, and wherein the controller is an electronic switch. 
     
     
         11 . The apparatus of  claim 8 , which further includes a valve in fluid communication with the expansion tank, the valve structured to divert condensate from the expansion tank when the controller operates upon a signal from the high condensate level sensor. 
     
     
         12 . The apparatus of  claim 11 , which further includes a conduit structured to supply water to the expansion tank from a utility water supply when the low condensate level sensor indicates a low condensate level in the expansion tank, and wherein. 
     
     
         13 . The apparatus of  claim 12 , which further includes a temperature sensor on an output side of the condenser, the controller structured to activate the pump to provide water to the condenser when a temperature signal of the temperature sensor satisfies a predetermined temperature value. 
     
     
         14 . The apparatus of  claim 13 , wherein the pump is locked out from activating when the low condensate level sensor provides a signal indicating a low condensate level. 
     
     
         15 . The apparatus of  claim 14 , wherein the high condensate level sensor includes a sensing element to sense a level of condensate which is located below a level which provides an overflow event. 
     
     
         16 . A method comprising:
 operating a gas compressor to pressurize a gas;   providing a pressurized gas from the gas compressor to a heat exchanger of a refrigerated dryer, the refrigerated dryer having a condenser, evaporator, and expansion tank, the evaporator in thermal communication with a pressurized gas passage of the heat exchanger, the expansion tank structured to receive condensate produced by operation of the evaporator;   harvesting condensate into the expansion tank which is produced by the evaporator as it cools the pressurized gas;   signaling a low condensate level in the expansion tank when condensate is at a low level;   signaling a high condensate level in the expansion tank when condensate is at a high level; and   diverting condensate from the expansion tank when condensate is at the high level.   
     
     
         17 . The method of  claim 16 , wherein the diverting includes providing a high condensate level signal to a controller, the controller structured to operate upon the signaling a high condensate level. 
     
     
         18 . The method of  claim 17 , wherein the diverting includes activating a valve to vent condensate from the expansion tank upon the signaling a high condensate level. 
     
     
         19 . The method of  claim 18 , which further includes supplying water from a utility water supply to the expansion tank upon the signaling a low condensate level in the expansion tank. 
     
     
         20 . The method of  claim 19 , which further includes pumping condensate from the expansion tank and supplying condensate to the condenser, and which further includes measuring a temperature of an outlet of the condenser and regulating the pump based upon the measuring a temperature. 
     
     
         21 . The method of  claim 16 , which further includes inhibiting the pump from withdrawing condensate from the expansion tank when the signaling a low condensate level in the expansion tank is occurring.