Air Compressor Control

Abstract

Controlling air compressors based on a temperature of air compressed by the air compressor. A temperature of air compressed by the air compressor is sensed. The sensed compressed air temperature is compared with a predetermined threshold temperature. The air compressor is deactivated when the sensed temperature exceeds the threshold temperature. The threshold temperature may be selected to inhibit carbon formation caused by oil thermal breakdown.

1 . A method of controlling an air compressor, comprising:
 a) sensing a pressure of compressed air in a reservoir;   b) comparing the sensed pressure of the compressed air in the reservoir with a predetermined threshold pressure;   c) activating the air compressor when the compressed air in the reservoir is less than the threshold pressure;   d) sensing a temperature of air compressed by the air compressor;   e) comparing the sensed temperature of the air compressed by the air compressor with a predetermined threshold temperature; and   f) deactivating the air compressor when the sensed temperature exceeds the threshold temperature and the sensed pressure is above the threshold pressure.   
   
   
       2 . The method of  claim 1  wherein the temperature of the air compressed by the air compressor is sensed in a compressor outlet port. 
   
   
       3 . The method of  claim 1  wherein the temperature of the air compressed by the air compressor is sensed at a compression chamber. 
   
   
       4 . A method for controlling an air compressor, comprising the steps of:
 a) receiving a signal indicative of the temperature of air compressed by the air compressor;   b) comparing the temperature to a predetermined threshold temperature value;   c) receiving a signal indicative of the pressure of compressed air in a reservoir;   d) comparing the pressure with a first predetermined threshold pressure value and a second predetermined threshold pressure value; and   e) providing a control signal to deactivate the air compressor in response to the temperature exceeding the predetermined threshold temperature value and the pressure being between the first predetermined threshold pressure value and the second predetermined threshold pressure value.   
   
   
       5 . The method of  claim 4  further comprising providing a control signal to activate the air compressor when the pressure is below the first threshold pressure value. 
   
   
       6 . The method of  claim 4  wherein the temperature is indicative of the temperature of air in a compressor outlet port. 
   
   
       7 . The method of  claim 4  wherein the temperature is indicative of the temperature of air in a compression chamber. 
   
   
       8 . The method of  claim 4  wherein the temperature is sensed by a temperature sensor mounted in a compressor unloader valve that is in fluid communication with a compression chamber. 
   
   
       9 . The method of  claim 4  wherein the threshold temperature value is representative of temperature at a compressor outlet port in a range from about 325 degrees Fahrenheit to about 400 degrees Fahrenheit. 
   
   
       10 . The method of  claim 4  wherein the threshold temperature value is selected to inhibit carbon formation in the air compressor caused by oil breakdown. 
   
   
       11 . A controller for an air compressor comprising:
 a) a first input for receiving a temperature signal, the temperature signal indicative of the temperature of air at an outlet of the air compressor;   b) a second input for receiving a pressure signal, the pressure signal indicative of pressure of air in a reservoir;   c) means for comparing the temperature with a predetermined threshold temperature value and the pressure with a first predetermined threshold pressure value and a second predetermined threshold pressure value; and   d) an output for providing an air compressor control signal, wherein the air compressor control signal deactivates the compressor when the temperature exceeds the predetermined threshold temperature value and the pressure is between the first predetermined threshold pressure value and the second predetermined threshold pressure value.   
   
   
       12 . A controller for an air compressor as in  claim 11  wherein the control signal activates the compressor when the pressure is below the first predetermined threshold pressure value. 
   
   
       13 . A controller for an air compressor comprising:
 a) a first input for receiving a signal indicative of the temperature of air compressed by the air compressor;   b) a second input for receiving a signal indicative of pressure of air in a reservoir;   c) means for deactivating the air compressor in response to the temperature exceeding a predetermined threshold temperature value and the pressure being between a first predetermined threshold pressure value and a second predetermined threshold pressure value.   
   
   
       14 . A control apparatus for an air compressor, comprising:
 a) means for receiving a signal indicative of the temperature of air compressed by the air compressor;   b) means for comparing the temperature of the air compressed by the air compressor with a predetermined threshold temperature value;   c) means for receiving a signal indicative of the pressure of compressed air in a reservoir;   d) means for comparing the pressure of the compressed air in the reservoir with a first predetermined threshold pressure value and a second predetermined threshold pressure value; and   e) means for providing a control signal to unload the air compressor when the temperature exceeds the predetermined threshold temperature value and the pressure is between the first predetermined threshold pressure value and the second predetermined threshold pressure value.   
   
   
       15 . A control apparatus for an air compressor as in  claim 14  further comprising means for receiving a signal indicative of the loaded state of the air compressor. 
   
   
       16 . A control apparatus for an air compressor as in  claim 15  further comprising providing a control signal to load the air compressor when the pressure is below the first predetermined threshold pressure value. 
   
   
       17 . The control apparatus of  claim 14  wherein the temperature is sensed by a temperature sensor mounted in a compressor unloader valve that is in fluid communication with a compression chamber. 
   
   
       18 . The control apparatus of  claim 14  wherein the threshold temperature value is representative of temperature at a compressor outlet port in a range from about 325 degrees Fahrenheit to about 400 degrees Fahrenheit. 
   
   
       19 . The control apparatus of  claim 14  wherein the threshold temperature value is selected to inhibit carbon formation in the air compressor caused by oil breakdown. 
   
   
       20 . A method of controlling an air compressor comprising:
 a) receiving a signal at a controller indicative of the loaded state of the air compressor;   b) receiving a signal at the controller indicative of a temperature of air compressed by the air compressor;   c) receiving a signal at the controller indicative of a pressure in an associated reservoir; and   d) providing a control signal from the controller to deactivate the air compressor in response to the compressor being in the loaded state, the temperature exceeding a predetermined threshold temperature value, and the pressure being between a first predetermined threshold pressure value and a second predetermined threshold pressure value.