Controller Apparatus and Method for a Compressed Air System

Abstract

A controller apparatus is provided for a compressed air system. The controller apparatus comprises a control output for transmitting a control signal to interrupt a charge cycle of an associated compressor in a loading state. The controller apparatus further comprises control logic capable of initiating an interrupted charge cycle of the compressor based upon a moisture accumulation value indicative of the extent of moisture accumulated in an associated air dryer during the charge cycle of the compressor in the loading state.

What is claimed is: 
     
         1 . A controller apparatus for a compressed air system, the controller apparatus comprising:
 a control output for transmitting a control signal to interrupt a charge cycle of an associated compressor in a loading state; and   control logic capable of initiating an interrupted charge cycle of the compressor based upon a moisture accumulation value indicative of the extent of moisture accumulated in an associated air dryer during the charge cycle of the compressor in the loading state.   
     
     
         2 . A controller apparatus according to  claim 1 , wherein the control logic maintains an interrupted charge cycle of the compressor until the moisture accumulation value drops below a predetermined moisture accumulation threshold value. 
     
     
         3 . A controller apparatus according to  claim 1 , wherein the control logic maintains an interrupted charge cycle of the compressor until an accumulated interruption time reaches a predetermined maximum interruption time limit. 
     
     
         4 . A controller apparatus according to  claim 3 , wherein the predetermined maximum interruption time limit is substantially equal to the sum of a predetermined maximum purge reservoir charge time limit and a predetermined maximum regeneration time limit. 
     
     
         5 . A controller apparatus according to  claim 4 , wherein prior to the control logic initiating the interrupted charge cycle, the control logic initiates charging a purge reservoir with compressed air from the compressor until an accumulated purge reservoir charge time reaches the predetermined maximum purge reservoir charge time limit. 
     
     
         6 . A controller apparatus according to  claim 1 , wherein the control logic iteratively interrupts the charge cycle of the compressor until the moisture accumulation value drops below a predetermined moisture accumulation threshold value, and iteratively regenerates the air dryer. 
     
     
         7 . A compressed air apparatus comprising:
 a service reservoir;   an air dryer;   a compressor for delivering compressed air through the air dryer to the service reservoir during a charge cycle of the compressor in a loading state; and   a controller arranged to interrupt the charge cycle of the compressor in the loading state in response to a wetness accumulation value associated with the air dryer reaching a predetermined wetness threshold value.   
     
     
         8 . A compressed air apparatus according to  claim 7 , wherein the controller is arranged to interrupt the charge cycle of the compressor in the loading state in response to a pressure in the service reservoir being within a predetermined pressure range and the wetness accumulation value associated with the air dryer reaching the predetermined wetness threshold value. 
     
     
         9 . A compressed air apparatus according to  claim 7  further comprising:
 a purge reservoir into which compressed air is delivered from the compressor when the compressor is in a loading state and from which compressed air is delivered through the air dryer to atmosphere to regenerate the air dryer, when the charge cycle of the compressor is interrupted in response to the wetness accumulation value associated with the air dryer reaching the predetermined wetness threshold value. 
 
     
     
         10 . A compressed air apparatus according to  claim 7 , wherein the charge cycle of the compressor in the loading state is interrupted until a predetermined maximum interruption time limit is reached. 
     
     
         11 . A compressed air apparatus according to  claim 7 , wherein the charge cycle of the compressor in the loading state is interrupted until the wetness accumulation value associated with the air dryer drops below the predetermined wetness threshold value. 
     
     
         12 . A compressed air apparatus according to  claim 11 , wherein the charge cycle of the compressor in the loading state is interrupted until the wetness accumulation value associated with the air dryer drops below the predetermined wetness threshold value minus a predetermined wetness hysteresis value. 
     
     
         13 . A compressed air apparatus comprising:
 a service reservoir;   an air dryer;   a compressor for delivering compressed air through the air dryer to the service reservoir when pressure in the service reservoir is between a cut in pressure and a cut out pressure; and   means for interrupting delivery of compressed air through the air dryer to the service reservoir when the pressure in the service reservoir is between the cut in pressure and the cut out pressure.   
     
     
         14 . A compressed air apparatus according to  claim 13 , wherein the means for interrupting delivery of compressed air through the air dryer to the service reservoir when the pressure in the service reservoir is between the cut in pressure and the cut out pressure includes:
 means for interrupting delivery of compressed air through the air dryer to the service reservoir when a wetness accumulation value associated with the air dryer reaches a predetermined wetness threshold value and the pressure in the service reservoir is between the cut in pressure and the cut out pressure.   
     
     
         15 . A compressed air apparatus according to  claim 13 , wherein the means for interrupting delivery of compressed air through the air dryer to the service reservoir when the pressure in the service reservoir is between the cut in pressure and the cut out pressure includes:
 means for interrupting delivery of compressed air through the air dryer to the service reservoir when the pressure in the service reservoir is between the cut in pressure plus a first pressure hysteresis value and the cut out pressure minus a second pressure hysteresis value.   
     
     
         16 . A method for interrupting operation of a compressor charge cycle to remove excess moisture accumulated in an air dryer through which compressed air from a purge reservoir flows to dry the compressed air, the method comprising:
 determining a moisture accumulation value indicative of the extent of moisture accumulated in the air dryer during a charge cycle of the compressor in a loading state; and   interrupting the charge cycle of the compressor when the moisture accumulation value reaches a predetermined moisture accumulation threshold value.   
     
     
         17 . A method according to  claim 16 , wherein interrupting the charge cycle of the compressor when the moisture accumulation value reaches a predetermined moisture accumulation threshold value includes:
 iteratively interrupting the charge cycle of the compressor until the moisture accumulation value drops below the predetermined moisture accumulation threshold value; and   iteratively regenerating the air dryer.   
     
     
         18 . A method according to  claim 16 , wherein interrupting the charge cycle of the compressor when the moisture accumulation value reaches a predetermined moisture accumulation threshold value includes:
 iteratively interrupting the charge cycle of the compressor until an accumulated interruption time reaches a predetermined maximum interruption time limit.   
     
     
         19 . A method according to  claim 16 , wherein determining a moisture accumulation value indicative of the extent of moisture accumulated in the air dryer during a charge cycle of the compressor in a loading state includes:
 determining the moisture accumulation value based upon an output parameter of the compressor during the charge cycle.   
     
     
         20 . A method according to  claim 19 , wherein determining the moisture accumulation value based upon an output parameter of the compressor during the charge cycle includes:
 determining the moisture accumulation value based upon flow rate of compressed air from the compressor through the air dryer during the charge cycle.   
     
     
         21 . A method according to  claim 16  further comprising:
 after the moisture accumulation value is determined and before the charge cycle of the compressor is interrupted, charging a purge reservoir with compressed air from the compressor until an accumulated purge reservoir charge time reaches a predetermined maximum purge reservoir charge time limit.