Drain Valve Assembly for Use in an Air Compressor System

Abstract

The present air compressor system includes an inlet connected to a compression stage, a cooling stage having an inlet connected to an outlet of the compression stage and having an outlet passage; a drain valve having an liquid inlet in and adjacent a bottom of the outlet passage of the cooling stage to drain condensation when opened; and a controller controlling the compression stage and the drain valve.

1 . An air compressor system comprising: 
 an inlet connected to a compression stage,    a cooling stage having an inlet connected to an outlet of the compression stage and an outlet passage;    a drain valve having a liquid inlet in and adjacent a bottom of the outlet passage of the cooling stage to drain condensation from the outlet passage when opened; and    a controller controlling the compression stage and the drain valve.    
   
   
       2 . The system of  claim 1 , wherein the liquid inlet of the drain valve is a siphon tube having an end adjacent a bottom of the outlet passage of the cooling stage.  
   
   
       3 . The system of  claim 2 , wherein the drain valve includes an air port connected to the outlet passage of the cooling stage whereby air passing from the air port to the drain through the open drain valve educes liquid from the outlet of the cooling stage through the siphon.  
   
   
       4 . The system of  claim 3 , wherein the air port is higher than the end of the siphon in the outlet passage of the cooling stage.  
   
   
       5 . The system of  claim 1 , wherein the system includes first and second compression stages and the cooling stage is the inter-cooling stage, and the inlet of the cooling stage is connected to an outlet of the first compression stage and the outlet passage of the cooling stage is connected to an inlet of the second compression stage.  
   
   
       6 . The system of  claim 1 , wherein the system includes first and second compression stages, and the inlet of the cooling stage is connected to an outlet passage of the second compression stage.  
   
   
       7 . The system of  claim 1 , including a check valve connecting the outlet passage of the cooling stage to a reservoir, and the drain valve is connected between the cooling stage and the check valve.  
   
   
       8 . The system of  claim 1 , wherein the drain valve is mounted in a pipe connected to and forming part of the outlet passage of the cooling stage, and the liquid inlet is in and adjacent a bottom of the pipe.  
   
   
       9 . The system of  claim 8 , the pipe is connected to the outlet passage of the cooling stage so that the bottom of the pipe adjacent the liquid inlet of the drain valve is the lowest point in the outlet passage.  
   
   
       10 . The system of  claim 1 , wherein a valve seat of the drain valve is higher than the liquid inlet.  
   
   
       11 . The system of  claim 1 , including a heater mounted adjacent the drain valve.  
   
   
       12 . The system of  claim 1 , wherein the controller operates the drain valve as an unloading valve for the compressor stage.  
   
   
       13 . The system of  claim 1 , wherein the drain valve is a pneumatic piston valve.  
   
   
       14 . The system of  claim 1 , wherein the drain valve is a solenoid valve.  
   
   
       15 . A drain valve assembly for an air compressor system, the drain valve assembly comprising: 
 a housing having a passage extending between a first and second port;    a valve chamber having a liquid inlet in and adjacent a bottom of the passage and having a drain outlet;    a valve seat in the valve chamber between the drain outlet and the liquid inlet;    a valve element responsive to an input signal to cover and uncover the valve seat.    
   
   
       16 . The assembly of  claim 15 , wherein the liquid inlet is an end of a siphon tube adjacent a bottom of the passage.  
   
   
       17 . The assembly of  claim 16 , wherein the valve chamber includes an air port connected to the passage whereby air passing from the air port to the drain outlet through the open valve seat educes liquid from the passage through the siphon.  
   
   
       18 . The assembly of  claim 17 , wherein the air port is higher than an end of the siphon connected to the passage.  
   
   
       19 . The system of  claim 15 , wherein the valve seat is higher than the liquid inlet.  
   
   
       20 . The system of  claim 15 , including a heater mounted to the housing adjacent the passage.