Abstract:
A fluid pressure regulator comprising a tubular housing having a fluid inlet at one end thereof and a fluid outlet at an opposite end and a fluid passage therebetween; a tubular plunger mounted for reciprocal movement in the fluid passage, the plunger having a flow control end and a piston end; a seat in the fluid passage including a seating surface located axially upstream of the plunger and adapted to be approached or engaged by a lower edge of the flow control end of the plunger, the seat supported centrally within the fluid passage by a single radially-oriented strut.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This invention relates to valves and pressure regulators generally, and specifically to a fluid (water) pressure regulator, particularly suited for (but not limited to) use in agricultural irrigation systems.  
         [0002]     It is well known to use pressure regulators in irrigation systems in order to provide constant, regulated outlet pressure over a wide range of regulator inlet pressures, to thereby insure the supply of water is maintained at a uniform pressure to a sprinkler or other irrigation device. The need for such regulators is particularly acute in low pressure systems because even slight variations in pressure along a system operating at low pressure causes much greater variations and discharges than the same system operating at high pressure.  
         [0003]     The assignee of this invention currently manufactures and sells fluid pressure regulators of the flow-through type, having an inlet at one end of a tubular housing and an outlet at the other end of the tubular housing. A valve or regulator seat is fixed within the housing and is adapted to be engaged by a tubular plunger which is spring biased away from the seat (in the direction of fluid flow) so that under normal conditions, maximum flow through the regulator is permitted. In the event of a pressure surge, the plunger is moved by back pressure within a diaphragm chamber, against the action of an opposed coil spring (and against atmospheric pressure), toward the regulator seat to thereby decrease flow through the regulator until the pressure is reduced, at which point the plunger will stop or, if pressure decreases sufficiently, move upwardly away from the seat to thereby increase the flow. In this way, the regulator constantly seeks an equilibrium position to maintain a uniform outlet pressure. The typical arrangement where the regulator or valve seat is located in the center of the flowpath, supported by multiple (e.g., four) radial struts or spokes, is problematic however, especially in dirty water conditions. Specifically, fibrous debris such as grass tends to hairpin about the radial struts and obstruct the flowpath, decreasing the operational performance characteristics of the regulator. Multiple struts also increase pressure loss through the regulator.  
       BRIEF DESCRIPTION OF THE INVENTION  
       [0004]     In accordance with one exemplary embodiment of the invention, the pressure regulator or valve seat is comprised of a circular disc supported concentrically within a center opening of an annular support ring that also corresponds to a center portion of the flowpath or fluid passage. In order to minimize the hairpinning problem experienced with prior pressure regulators, the circular disc is supported within the center opening of the support ring by a single radially extending strut. In one embodiment, the underside of the strut has a rounded V-shape along its underside, with the majority of the strut located below or axially upstream of the seat. In a second embodiment, the underside of the strut is sloped upwardly from its radially outer end to its radially inner end to even further reduce the possibility of fibrous material hairpinning and remaining on the strut.  
         [0005]     Accordingly, in one aspect, the present invention relates to a fluid pressure regulator comprising a tubular housing having a fluid inlet at one end thereof and a fluid outlet at an opposite end and a fluid passage therebetween; a tubular plunger mounted for reciprocal movement in the fluid passage, the plunger having a flow control end and a piston end; a seat in the fluid passage including a seating surface located axially upstream of the plunger and adapted to be approached or engaged by a lower edge of the flow control end of the plunger, the seat supported centrally within the fluid passage by a single radially-oriented strut.  
         [0006]     In another aspect, the invention relates to a valve seat for a valve or pressure regulator comprising an annular support ring defining a central flow opening and a disc having a seating surface supported concentrically within the center opening by a single radially-oriented strut.  
         [0007]     In still another aspect, the invention relates to a valve seat for a valve or pressure regulator comprising an annular support ring defining a central flow opening and a disc having a seating surface supported concentrically within the center opening by a single radial strut connected to an underside of the disc; wherein the seating surface is surrounded by an upstanding peripheral flange; and further wherein the underside of the strut is formed with an underside that slopes in a downstream direction from a radially outer end thereof to a radially inner end thereof.  
         [0008]     The invention will now be described in detail in connection with the drawings identified below. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a cross section through a pressure regulator in accordance with an exemplary embodiment of the invention;  
         [0010]      FIG. 2  is a perspective view of a pressure regulator seat removed from the pressure regulator shown in  FIG. 1 ;  
         [0011]      FIG. 3  is a plan view of the pressure regulator seat shown in  FIG. 2 ;  
         [0012]      FIG. 4  is a side elevation of the pressure regulator seat shown in  FIG. 2 ; and  
         [0013]      FIG. 5  is a side elevation of a pressure regulator seat in accordance with a second embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0014]     With reference to  FIGS. 1-3 , a fluid pressure regulator  10  in accordance with an exemplary embodiment of this invention includes a tubular housing including an inlet section  12  and an outlet section  14  secured together by means of fasteners such as screws  16 . The pressure regulator  10  is of the flow-through type, with an inlet  18  provided at one end of inlet housing section  12 , and an outlet  20  provided at the distal end of the outlet housing section  14 . It will further be appreciated that the inlet  18  of the regulator may be threaded internally or externally in any of a number of thread configurations and sized to facilitate attachment to variously sized hoses or other conduits. The outlet  20  is shown to be externally threaded (but could be interiorly threaded), and is adapted to receive in a typical arrangement, a rotary impact type sprinkler, a fixed spray head, or other sprinkler device.  
         [0015]     In the following description, any reference to “upper” or “lower” is based on the orientation of the pressure regulator as shown in  FIG. 1  and is not intended to in any way limit the scope of the invention.  
         [0016]     A tubular sleeve  22  is located within the inlet section  12 , with a cap  24  substantially closing the upper open end of the sleeve  22 . The lower end  26  of the sleeve and the cap  24  are each formed with axially aligned center openings that permit a piston or plunger  28  to move axially back and forth within the openings. The piston or plunger  28  is provided with a radial piston flange  30  nearer the upper end of the plunger, with a disc-like spring retainer  32  located adjacent and upstream (in a flow direction) of the piston flange  30 . A flexible diaphragm  34  extends radially between the housing and the piston or plunger. Specifically, the radially outer end of the diaphragm is clamped between the upper end of sleeve  22  and the lower end of the cap  24 , and the radially inner end of the diaphragm is clamped between the spring retainer  32  and the piston flange  30 . This arrangement creates a pressure or diaphragm chamber  36  between the diaphragm  34  and the cap  24  that is subject to regulator outlet pressure via a path from a series of cut-outs  38  in the upper end of sleeve  22 , along the piston or plunger  28 , and past an O-ring  40  located in an annular recess  42  in the outlet housing section  14 .  
         [0017]     A coil spring  44  is arranged within the sleeve  22  and surrounds the plunger  28 . The spring  44  extends axially between the radially-oriented bottom wall  46  of the sleeve  22  and the spring retainer  32 , thus biasing the plunger  28  in an upward or maximum flow direction.  
         [0018]     Within the inlet section  12  of the regulator housing, and adjacent the inlet  18 , there is formed an annular shoulder  48  and an adjacent cylindrical surface  50 . These surfaces are designed to receive a replaceable, plastic valve or regulator seat  52 .  
         [0019]     The regulator seat  52 , best seen in  FIGS. 2-4 , comprises a circular disc  54  supported concentrically within a center opening  56  of an annular support ring  58 . More specifically, the circular disc  54  includes a substantially flat, annular seating surface  60  substantially surrounded by an upstanding peripheral annular flange or wall  62 . The center of the disc  54  is formed with a blind recess  64  in the molding process. A single, radially-oriented support strut  66  extends from the underside of recess  64  (i.e., approximately centered relative to the seat  52 ) radially outwardly to the annular support ring  58 .  FIGS. 1 and 4  clearly illustrate the rounded V-shaped profile of the underside of the strut  66 .  
         [0020]     The annular support ring  58  is formed with a flat annular surface  68  on its underside that seats on the annular horizontal shoulder  48  located adjacent the internal thread  70  at the inlet  18 . Circumferentially spaced vertical ribs  72  reduce friction between the annular support ring  58  and the housing surface  50 , facilitating removal and/or replacement of the seat if needed. A flat upper surface  74  of the support ring  58  is engaged by the lower edge of an annular wall  76  on the sleeve  22 . An annular rib  78  on upper surface  74  of the seat  52  locates the sleeve vis-à-vis the support ring  58  in that rib  78  is received between the wall  76  and a concentric radially inner wall  80  also formed on the lower edge of the sleeve  22 .  
         [0021]     By supporting the seat  52  in this manner, it can be appreciated that surface area dedicated to supporting the seat within the center of the regulator flowpath or fluid passage has been kept to a minimum. As best seen in  FIG. 4 , there is an open flowpath of about 340° around the seat, significantly reducing the potential for obstruction, and also minimizing pressure loss through the regulator.  
         [0022]     Seat  52  is preferably formed of a rigid plastic material, for example, a glass fiber reinforced polyphenylene sulfide (PPS) resin. Preferably, the material has a minimum flexural modulus of 1.8 Msi (ASTM D790).  
         [0023]     For one size regulator, the seat  52  may have an outside diameter of 0.494 inch and the support ring  58  may have an inner diameter of 0.669 inch. The outer diameter of the support ring  58  may be 1.135 inch and the height may be 0.400 inch. Of course, the dimensions may change for different size regulators.  
         [0024]     Returning to  FIG. 1 , adjacent the annular walls  76  and  80 , there are seated a pair of inner and outer O-rings  82 ,  84 , respectively, which insure that fluid flowing through the regulator, in the direction from inlet  18  to outlet  20  as indicated by the flow arrow F, is constrained to flow through the reciprocable plunger  28  and around the seat  52  as described below.  
         [0025]     Note that the cap  24  is held securely in place within a counterbore formed in the housing outlet section  14  so that, upon assembly of the upper housing section  14  to the lower housing inlet section  12 , the sleeve  22 , cap  24  and seat  52  are firmly clamped and thus fixed within the housing.  
         [0026]     The upper end of the regulator plunger  28  (above the piston flange  30 ) slides or reciprocates within the center opening of the sleeve cap  24 . The outer peripheral surface engages O-ring  40  as it reciprocates within the housing, and the upper end of the plunger  28  terminates at a free, downstream end  86  that is adapted to engage an annular shoulder  88  provided in the upper housing section  14 , thus providing a stop for upward or opening movement of the plunger  28 .  
         [0027]     In use, fluid flows through the regulator from inlet  18  around the seat  52  and through the plunger  28  and outlet  20 . Under normal flow pressure conditions, the plunger  28  is biased upwardly as viewed in  FIG. 1  so that the flow through the regulator is maximized. In the event of a pressure build-up within the line or device downstream of the outlet  20 , water pressure in chamber  36  will increase, causing the plunger  28  to move in an upstream direction toward the seat surface  60 . The diaphragm  34  maintains an effective fluid-tight seal so that no fluid enters the chamber  90  between the plunger  28  and the sleeve  22  in which the spring  44  is located. Chamber  90  is, however, vented to atmosphere by a plurality of notches or grooves (not shown), and, therefore, pressure exerted on piston flange  30  must not only overcome spring  44 , but atmospheric pressure as well.  
         [0028]     Depending upon the amount of back pressure developed within the regulator  10 , the plunger  28  may move downwardly so that the tapered annular edge  92  approaches the surface  60  to reduce flow through the regulator, or under extreme pressure conditions, seats on surface  60  to thereby prevent flow through the regulator. Upon a subsequent decrease in back pressure, the spring  44 , along with atmospheric pressure, will serve to overcome whatever back pressure is present to thereby move the plunger  28  upwardly toward the outlet  20 , thereby opening the fluid flow passage between the plunger  28  and the seat  52 . In this way, the plunger or piston  28  continuously seeks an equilibrium position, insuring uniform pressure at the outlet  20 .  
         [0029]     With reference now to  FIG. 5 , an alternative seat  152  is similar to seat  52  and, as such, similar reference numerals, but with the prefix “1” added, are used to designate corresponding parts of the seat. The shape of strut  166  has been altered so that its underside (i.e., the surface exposed to the inlet flow) slopes upwardly, i.e., in a downstream direction, from its radially outer end to its radially inner end. The sloped surface further assists in preventing hairpinning of fibrous debris in that the fibrous material is likely to slide along the strut and be carried away by the flow of water through the regulator. To accommodate the reconfigured strut  166 , an axial slot (not shown) must be provided in the housing section  12 , extending partially through the thread  70  ( FIG. 1 ).  
         [0030]     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.