Method and apparatus for decompressing a compressor

Abstract

Methods, computer readable media, and apparatus are disclosed for decompressing an air compressor. The methods including compressing air, the compressed air flowing through a first path through a first non-return valve to a first receiver; and in response to determining to take the air compressor off-load, closing an air inlet valve of the air compressor to stop air from entering the air compressor, opening a second path from the air outlet of the air compressor to approximately atmospheric pressure to lower the air pressure at the air inlet of the air compressor, stopping a first flow of oil from the first receiver to the air compressor, wherein the first flow of oil is for cooling the compressor, stopping a second flow of oil from a separator for a working air to the air compressor, and flowing oil from the first receiver to the air compressor for lubrication.

1 . An air compressor system, comprising:
 an air compressor having an air inlet and an air outlet, the air compressor configured to compress air from the air inlet and to deliver a volume of compressed air to the air outlet;   an adjustable air inlet valve connected to the air inlet of the air compressor, wherein the adjustable air inlet valve is configured to be adjustable to regulate how much air can flow into the air inlet of the air compressor;   a first receiver having an air inlet and an air outlet, the first receiver configured to store compressed air;   a main air discharge passage connected to the air outlet of the air compressor and the air inlet of the first receiver;   a first non-return valve disposed in the main air discharge passage between the air outlet of the air compressor and the air inlet of the receiver;   a second receiver having an air inlet and an air outlet, the second receiver configured to separate oil from compressed air;   a secondary discharge passage connected to the air inlet of the second receiver and the main air discharge passage upstream from the first non-return valve;   an oil separator disposed in the first receiver;   a first oil line disposed to permit oil to flow from the oil separator to the air compressor;   a first oil stop valve disposed in the first oil line and configured to have an open position where oil can flow between the oil separator and the air inlet of the air compressor and a closed position where the oil cannot flow between the oil separator and the air inlet of the air compressor;   a second oil line disposed to permit oil to flow from the first receiver to the air compressor;   a second oil stop valve disposed in the second oil line and configured to have an open position where oil can flow from the first receiver to the air compressor and a closed position where oil cannot flow from the first receiver to the air compressor;   an isolation valve disposed in the air flow between the main air discharge passage and the air inlet of the second receiver, wherein the isolation valve is configured to have an open position where air from the main air discharge passage can flow through the secondary discharge passage and a closed position where air from the main air discharge passage cannot flow through the secondary discharge passage; and   a controller in communication with the adjustable air inlet valve and the isolation valve, wherein the controller is configured to take the air compressor off load by shutting the adjustable air inlet valve and opening the isolation valve, wherein the first oil stop valve and the second oil stop valve are configured to be open when the air compressor is on load and to be closed when the air compressor is off load.   
     
     
         2 . The air compressor system of  claim 1 , further comprising:
 a second non-return valve disposed in the air flow between the secondary discharge passage and the air outlet of the second receiver;   
     
     
         3 . The air compressor system of  claim 1 , wherein the second non-return valve is configured to maintain the second receiver at approximately atmospheric pressure. 
     
     
         4 . The air compressor system of  claim 1 , further comprising a third oil line configured to permit oil to flow from the first receiver to the air compressor. 
     
     
         5 . The air compressor system of  claim 1 , wherein the controller is further configured to first shut the adjustable inlet valve and then after waiting a predetermined time to open the isolation valve. 
     
     
         6 . The air compressor system of  claim 1 , further comprising an engine configured to drive the air compressor. 
     
     
         7 . The air compressor system of  claim 2 , wherein the second non-return valve is disposed between the air outlet of the second receiver and atmospheric air. 
     
     
         8 . The air compressor system of  claim 1 , further comprising a secondary air compressor having an air inlet and an air outlet, wherein the air inlet is disposed to compress air from the air outlet of the compressor to deliver a volume of compressed air to the air inlet of the second receiver, and wherein the controller is further configured to turn on the secondary air compressor after opening the isolation valve and closing the adjustable air inlet valve. 
     
     
         9 . The air compressor system of  claim 1 , further comprising a pressure sensor in communication with the controller and disposed to measure the pressure of the first receiver, wherein the controller is further configured to determine when to take the air compressor off load based at least partially on the measured air pressure of the first receiver, and wherein the controller is configured to take the air compressor off load by closing the adjustable air inlet valve, opening the isolation valve, and turning the secondary air compressor on. 
     
     
         10 . The air compressor system of  claim 1 , further comprising an oil line connected to the second receiver and connected to one of: the main discharge passage upstream from the first non-return valve, the main discharge passage downstream from the first non-return valve, and the first receiver. 
     
     
         11 . The air compressor system of  claim 1 , further comprising a second isolation valve in communication with the controller;
 a pressure sensor in communication with the controller and disposed to measure the pressure of the first receiver, wherein the controller is further configured to take the air compressor off load by determining a pressure of the first receiver, and if the pressure of the first receiver is below a threshold value then closing the isolation valve and opening the second isolation valve, otherwise opening the isolation valve and closing the second isolation valve; and   a secondary air compressor having an air inlet and an air outlet, wherein the air inlet is disposed to compress air from the air outlet of the compressor to deliver a volume of compressed air to the secondary discharge passage, and wherein the controller is further configured to turn on the secondary air compressor after closing the adjustable air inlet valve.   
     
     
         12 . A method of decompressing an air compressor having an air inlet and an air outlet, the method comprising:
 compressing air from an air inlet to an air outlet, the compressed air flowing through a first path through a first non-return valve to a first receiver; and   in response to determining to take the air compressor off-load, closing an air inlet valve of the air compressor to stop air from entering the air compressor, opening a second path from the air outlet of the air compressor to approximately atmospheric pressure to lower the air pressure at the air outlet of the air compressor, stopping a first flow of oil from the first receiver to the air compressor, wherein the first flow of oil is for cooling the compressor, stopping a second flow of oil from a separator for a working air to the air compressor, and flowing oil from the first receiver to the air compressor for lubrication.   
     
     
         13 . The method of  claim 12 , wherein opening a second path comprises:
 opening a second path by opening a second non-return valve from the air outlet of the air compressor to a second receiver, wherein the second receiver is at approximately atmospheric pressure.   
     
     
         14 . The method of  claim 12 , wherein opening a second path includes opening a second path by opening an isolation valve, wherein the isolation valve is connected to the air outlet of the air compressor upstream from the first non-return valve. 
     
     
         15 . The method of  claim 12 , wherein stopping air from entering the air inlet of the compressor comprises:
 stopping air from entering the air inlet of the air compressor by closing an air inlet valve of the compressor.   
     
     
         16 . The method of  claim 12 , further comprising turning on a second air compressor disposed in the second path to suck air out of the air inlet of the air compressor. 
     
     
         17 . The method of  claim 12 , wherein the second reserve is connected to a non-return valve and the non-return valve is connected to atmospheric pressure. 
     
     
         18 . The method of  claim 12 , further comprising separating oil from the compressed air in the second receiver and flowing the oil to the first receiver. 
     
     
         19 . A method of decompressing an air compressor having an air inlet and an air outlet, the method comprising:
 compressing air from an air inlet to an air outlet, the compressed air flowing through a first path through a first non-return valve to a first receiver; and   in response to determining to take the air compressor off-load,   
       closing an air inlet valve of the air compressor to stop air from entering the air compressor, and 
       if a receiver pressure is above a threshold, then opening a second path from the air outlet of the air compressor to approximately atmospheric pressure, otherwise opening a third path from the air outlet of the air compressor to the first receiver. 
     
     
         20 . The method of  claim 19 , further comprising stopping a first flow of oil from the first receiver to the air compressor, wherein the first flow of oil is for cooling the compressor, stopping a second flow of oil from a separator for a working air to the air compressor, and flowing oil from the first receiver to the air compressor for lubrication.