Combined oil and water separator in an air brake dryer

Abstract

A filter assembly for separating and removing a liquid from a compressed fluid stream includes a filter element for separating the liquid from the fluid, a purge valve, and an elongated valve operator for actuating the purge valve. The top of the filter element has a shroud that decreases the flow area of the entering fluid stream to induce a vortex of the fluid, allowing the liquid to separate from the fluid. The purge valve is located at the bottom of the filter element for draining the separated liquid. The elongated valve operator axially extends through the filter element and is moveable by an actuating piston located at the top of the filter element, in response to elevated pressure in the filter assembly. The filtered air is dried through a desiccant body and then outputted from the filter assembly to be used in an air brake system.

What is claimed is: 
     
         1 . A filter element for separating and removing a liquid from a fluid comprising:
 a longitudinally extending body of coalescing media for separating the liquid from the fluid having a top end and a bottom end distally opposite the top end; and   a purge valve assembly at the bottom end of the body of coalescing media, wherein the purge valve assembly has a purge valve biased in a closed position and ii moveable to an open position to drain the liquid out of the filter assembly, a sump for holding the liquid when the purge valve is in the closed position, and a valve seat defined by the sump against which the purge valve is seated when in the closed position.   
     
     
         2 . The filter element according to  claim 1  further comprising:
 an elongated valve operator axially extending through the body of coalescing media between the top end and the bottom end, wherein the elongated valve operator is configured to move the purge valve between the closed position and the open position. 
 
     
     
         3 . The filter element according to  claim 2 , wherein the elongated valve operator engages a head of the purge valve. 
     
     
         4 . The filter element according to  claim 1 , wherein the bottom end defines a purge port and the purge valve assembly is arranged in the purge port. 
     
     
         5 . The filter element according to  claim 1  further comprising an actuating piston located proximate the top end and distally opposite the purge valve, wherein the actuating piston moves the purge valve. 
     
     
         6 . The filter element according to  claim 1 , wherein the purge valve assembly is arranged along a longitudinal axis defined by the body of coalescing media. 
     
     
         7 . The filter element according to  claim 1  further comprising a spring that biases the purge valve in the closed position. 
     
     
         8 . The filter element according to  claim 1 , wherein the purge valve is a poppet valve. 
     
     
         9 . The filter element according to  claim 1 , wherein the sump is cone-shaped. 
     
     
         10 . The filter element according to  claim 1 , wherein the filter element includes a first end cap having a central body portion fixed to the top end of the body of coalescing media, and a second end cap arranged at the bottom end of the body of coalescing media. 
     
     
         11 . The filter element according to  claim 10 , wherein the second end cap has a central body portion in which the purge valve assembly is contained. 
     
     
         12 . The filter element according to  claim 10 , wherein the second end cap has a radially extending flange for attaching the second end cap to the second end of the body of coalescing media. 
     
     
         13 . The filter element according to  claim 10 , wherein the second end cap has a snap ring for securing the purge valve assembly within the second end cap. 
     
     
         14 . The filter element according to  claim 10 , wherein the purge valve assembly is housed in the second end cap. 
     
     
         15 . The filter element according to  claim 10 , wherein the first end cap has a shroud that extends longitudinally from the central body portion and has a radially outer annular surface that progressively increases in diameter from a first end of the shroud to a second end of the shroud in a direction toward the bottom end of the of body of coalescing media. 
     
     
         16 . A filter assembly for separating and removing a liquid from a fluid comprising:
 the filter element according to  claim 1 ;   a filter head having a fluid inlet and an actuating piston; and   an elongated valve operator that axially extends through the filter element between the top end and the bottom end and is configured to move the purge valve between the closed position and the open position, wherein the actuating piston is configured to move the purge valve by acting on the valve operator, in response to elevated pressure in the filter assembly.   
     
     
         17 . The filter assembly according to  claim 16 , wherein the filter head includes an atmospheric reference chamber and a governor pressure chamber that are separated by the actuating piston, wherein the actuating piston is moveable within the atmospheric reference chamber when elevated pressure is communicated to the governor pressure chamber. 
     
     
         18 . The filter assembly according to  claim 17 , wherein the fluid inlet is spiral-shaped and the filter element is configured to reduce a flow area of fluid entering the filter element from the fluid inlet, to induce a vortex of the fluid. 
     
     
         19 . The filter assembly according to  claim 18  further comprising:
 a shroud at the top end of the filter element that extends longitudinally from a first end toward a second end of the shroud and has a radially outer annular surface that progressively increases in diameter from the first end toward the second end of the shroud, wherein the shroud is configured to reduce the flow area of fluid to induce the vortex, and accelerate a speed of the vortex, allowing the liquid to separate from the vortex.