Hydraulic filter assembly with priority valve

Abstract

A filter module assembly utilizes a priority valve installed in a manifold to allow for continuous filtration of hydraulic fluid up to a predetermined flow value and diverts occasional high flow to a secondary circuit. This arrangement provides both a low pressure drop at a high flow condition and structural integrity (1,000,000 impulse cycles from 0 to 6000 psi) while at the same time reducing the weight by as much as 50% from a conventional design approach.

1 . A fluid flow rate responsive valve comprising: 
 (a) a valve body having a first end and a second end and defining an inlet for fluid flow through said first end, the valve body including: 
 (i) a plurality of first circular apertures defined through the periphery of the valve body and disposed towards said first end so as to define a secondary outlet; and  
 (ii) a plurality of second circular apertures defined through the periphery of the valve body and disposed towards said second end so as to define a primary outlet;  
   (b) a piston having a first end and a second end in corresponding relationship to the valve body's first and second ends, wherein the piston includes a plurality of circular apertures through the periphery thereof and a metering orifice, said piston being coaxial with, and slidably mounted within, the valve body; and    (c) a spring disposed adjacent the piston's second end, wherein the spring is biased to: 
 (i) urge the piston into a first position within the valve body to close the piston over the plurality of first circular apertures when the flow rate of the fluid through the inlet is below a predetermined threshold value, thereby allowing all of the fluid to pass from the inlet through the metering orifice and to the primary outlet; and  
 (ii) allow the piston to move away from the first position to expose the plurality of first circular apertures when the flow rate of the fluid through the inlet is above the threshold value, whereby the amount of fluid above the threshold value is directed away from the primary outlet and through said secondary outlet while the amount of fluid at and below the threshold value continues to pass through the metering orifice to the primary outlet.  
   
   
   
       2 . The valve according to  claim 1 , wherein the spring is configured such that the amount of exposure of the plurality of first circular apertures is proportional to the flow rate of the fluid.  
   
   
       3 . The valve according to  claim 1 , wherein the piston includes a first cylindrical portion adjacent said first piston end and a second cylindrical portion adjacent said second piston end, and the first portion has a larger diameter than the second portion.  
   
   
       4 . The valve according to  claim 3 , wherein the piston's plurality of circular apertures are defined through the periphery of said second cylindrical portion.  
   
   
       5 . The valve according to  claim 3 , wherein the metering orifice is defined through the interface between said first and second cylindrical portions.  
   
   
       6 . The valve according to  claim 1 , further including a retainer member disposed on an underside of the piston's second end and a spring guide disposed between said retainer and said spring.  
   
   
       7 . The valve according to  claim 1 , wherein the valve body's second end is capped off with an end fitting.  
   
   
       8 . A fluid flow rate responsive valve comprising: 
 (a) a valve body having a first end and a second end and defining an inlet for fluid flow through said first end, the valve body including a plurality of first circular apertures and a plurality of second circular apertures defined through the periphery of the valve body so as to define, respectively, a secondary outlet and a primary outlet;    (b) a piston having a first end and a second end in corresponding relationship to the valve body's first and second ends, wherein the piston includes a plurality of circular apertures through the periphery thereof and a metering orifice, said piston being coaxial with, and slidably mounted within, the valve body;    (c) a spring guide disposed adjacent the piston's second end; and    (d) a spring disposed on said spring guide such that, when a fluid flow rate through the inlet increases above a predetermined threshold value, the piston moves relative to the valve body to allow the amount of fluid above the threshold value to be directed away from the primary outlet and through the secondary outlet while the amount of fluid at and below the threshold value continues to pass through the metering orifice to the primary outlet.    
   
   
       9 . The valve according to  claim 8 , wherein the piston includes a first cylindrical portion adjacent said first piston end and a second cylindrical portion adjacent said second piston end, and the first portion has a larger diameter than the second portion.  
   
   
       10 . The valve according to  claim 9 , wherein the piston's plurality of circular apertures are defined through the periphery of said second cylindrical portion.  
   
   
       11 . The valve according to  claim 9 , wherein the metering orifice is defined through the interface between said first and second cylindrical portions.  
   
   
       12 . The valve according to  claim 8 , wherein the plurality of first circular apertures are disposed towards the valve body's first end and the plurality of second circular apertures are disposed towards the valve body's second end.  
   
   
       13 . The valve according to  claim 8 , wherein the valve body's second end is capped off with an end fitting.