Self-flushing irrigation valve

Abstract

A self-flushing irrigating valve formed, at least in part, of an elastically deformable material which, when subjected to differential pressures below a preselected value, occupies an open position forming a passage for the flushing of water therethrough; and when subjected to differential pressures above a preselected value, forms a constricted passage for trickle flow of water therethrough. The valve, when in its trickle flow condition, tends to effect further constriction on further increase in differential pressure thereby tending to produce a uniform flow rate through a range of effective pressures.

I claim: 
     
       1. A self-flushing valve for disposition in a chamber, the chamber being subjected periodically to fluid under pressure whereby, on initiation of a pressure period, the fluid pressure progressively rises from a minimum pressure to a maximum pressure and, on termination of the pressure period, the fluid pressure progressively falls from its maximum pressure to the minimum pressure, the self-flushing valve comprising: a. means forming an exit port in the chamber and, on flow of fluid therethrough, creating in its vicinity, a region of reduced pressure;   .[.b. and valve means including at least one flexible wall formed of elastomeric material having a first surface subjected to the fluid pressure in the chamber as supplied thereto, and an opposing surface exposed to the pressure as reduced in the vicinity of the exit port;   c. the wall being yieldably biased, when the difference between the chamber pressure and reduced pressure is below a predetermined value to occupy a position permitting flushing flow of liquid through the exit port and outlet;   d. the wall being movable, when the difference between said pressures exceeds said predetermined value, to throttle the exit port;   e. and the wall, when in its throttling position defining at least in part, a trickle passage forming an entrance to the exit port..]. .Iadd.   b. and a tubular valve means including confronting wall elements defining an exit end and an entrance end displaced axially from the exit end, the interior of the valve means being exposed to said region of reduced pressure and including opposed wall elements, at least one of which is formed of elastomeric material adapted to occupy a first position forming with the other wall elements, an axially extending flush passage discharging through the chamber exit port, and a second position collapsed toward the other wall elements to form therewith a trickle passage of substantially reduced cross-sectional area;   c. the flexible wall element being responsive to increase of the pressure differential in the chamber and the flush passage above a predetermined value to cause movement of the wall element from its first position to its second position thereby converting the flush passage to a trickle passage;   d. the flexible wall element exerting a counterforce, when in its second position, tending to return the wall element to its first position, and being movable from its second position to its first position upon reduction of the pressure differential in the chamber and trickle passage below said predetermined value. .Iaddend.   
     
     
       2. A self-flushing valve as defined in claim 1, wherein: .[.a. the wall is part of a tubular member extending into the chamber from the exit port and providing a plurality of said walls forming, when in their biased condition, a flushing passage preceding the exit port, and mutually collapsible to form said trickle passage..]. .Iadd.   a. a plurality of flexible wall elements are provided and are mutually collapsible to form said trickle passage. .Iaddend.   
     
     
       3. A self-flushing valve as defined in claim 1, wherein: a. the valve means includes a rigid wall .Iadd.element .Iaddend.confronting the flexible wall .Iadd.element, .Iaddend..[.the.]. .Iadd.said .Iaddend.wall .Iadd.elements .Iaddend..[.being complementary.]. .Iadd.complementing each other .Iaddend.to form the flushing passage or the trickle passage.  .[.4. A self-flushing valve as defined in claim 1, wherein:   a. a valve seat surrounds the entrance end of the exit port;   b. the wall is a flap member biased to an angular position, clearing the valve seat for flushing flow of fluid and yieldably movable into engagement with the valve seat to throttle the exit port;   c. and the trickle passage is a groove defined between the flap and the   
     
     
        valve seat when the flap is in its throttling position..]. 5. A self-flushing valve as defined in claim 1, wherein: a. .[.portions of the.]. .Iadd.said flexible .Iaddend.wall element .[.of the trickle passage are contrictable.]. .Iadd.is yieldable .Iaddend.in .Iadd.direct .Iaddend.response to increasing pressure in the chamber above said predetermined value .[.thereby tending.]. to maintain a .Iadd.substantially .Iaddend.constant rate of trickle .Iadd.flow through the outlet over a relatively wide range of pressure variations in the   
     
     
        chamber. .Iaddend. 6. A self-flushing valve for controlling flow from a periodically pressurized fluid system wherein fluid pressure progressively rises from a minimum pressure to a maximum pressure on initiation of a pressure period and progressively falls from the maximum pressure to the minimum pressure on termination of the pressure period, the self-flushing valve comprising: a. housing means defining a chamber having a major inlet communicating with the fluid system and a minor outlet for the discharge of fluid from the system;   b. and a tubular valve formed, at least in part, of elastomeric material disposed in the chamber, one end thereof being in communication with the outlet, and the other end thereof positioned to receive fluid through the inlet for flow within the tubular valve to the outlet;   c. at least portions of the walls of the .[.tube.]. .Iadd.tubular valve .Iaddend.being in confronting relation and forming outer surfaces exposed to pressure of the fluid in the chamber surrounding the valve, and inner surfaces exposed to the reduced pressure incidental to flow of fluid through the valve and outlet;   d. said walls being biased, when the pressure differential across the walls is below a preselected value, to maintain the tubular valve in a condition for flushing said value, said walls being collapsible toward each other to reduce the flow therethrough to a trickle flow;   e. the tubular valve on reduction of pressure differential across said walls, tending to return to a condition of flushing flow, whereby the tubular valve assumes a flushing condition at the beginning and end of   
     
     
        each pressure period. 7. A self-flushing valve as defined in claim 6, wherein: a. the tubular valve is polygonal in cross section, each side having obtusely related walls confronting like walls and defining, when the valve is in its flushing flow condition, a central bore with radiating channels, and defining, when the valve is in its trickle flow condition, a minute   
     
     
        central passage. 8. A self-flushing valve as defined in claim 6, wherein: a. the tubular valve is formed by a pair of walls .[.joined at their margins.]., the midportions of the walls being spaced from each other when the valve is in its flushing flow condition, and in mutual contact when the valve is in its trickle flow condition, at least one of the walls having a minute flow channel forming with the other wall, a passageway to   
     
     
        effect the trickle flow condition. 9. A self-flushing valve as defined in claim 6, wherein: a. the tubular valve is polygonal in cross section and at least one trickle flow channel extends along at least one of the walls, the inner surfaces of the walls being spaced from each other when the valve is in its flushing flow condition, and being in mutual contact when the valve is in its trickle flow condition except for the trickle flow channel and   
     
     
        covering portion of a confronting wall. 10. A self-flushing valve as defined in claim 6, wherein: a. the chamber is annular and the housing means receives a centrally disposed supply tube;   b. a set of tubular valves is joined to and extends axially from a common   
     
     
        base ring surrounding the supply tube. 11. A self-flushing valve as defined in claim 10, wherein: a. each tubular valve includes a longitudinally faceted fixed wall forming a circular wall of the chamber, and a pair of confronting faceted yieldable walls defining with the fixed wall a generally triangular flushing passage, the walls being mutually engageable with each other and with the fixed wall to close the flushing passage to a trickle passage.   
     
     
            A self-flushing valve as defined in claim 6, which further includes: a. an anti-syphon valve .Iadd.causing .Iaddend.admission of air into the   
     
     
        chamber on generation of a negative pressure therein. 13. A self-flushing valve as defined in claim 6, wherein: a. said walls are further yieldable after forming the trickle passage to cause shrinking of the trickle passage with increased pressure differential thereby tending to produce constant trickle flow with change   
     
     
        in supply pressure in the range above said preselected value. 14. A self-flushing valve as defined in claim 6, wherein: a. the housing means includes a pair of complementary cylindrical housing members, one axial end thereof being adapted for connection to a supply line and forming the inlet to the chamber, the opposite axial end having .Iadd.a plurality of .Iaddend.said .[.outlet .]. .Iadd.outlets .Iaddend.;   b. and a .[.single.]. .Iadd.ring of .Iaddend.tubular valve means is   
     
     
        disposed axially in the chamber. 15. A self-flushing valve as defined in claim 6, wherein: a. the housing means includes a pair of complementary cylindrical housing members, one axial end thereof being adapted for connection to a supply line and forming a centrally disposed inlet, the chamber being annular and surrounding the inlet;   b. at least one axial end of the housing means having a ring of said outlets;   c. a set of the tubular valves are arranged in a circle and are joined to a common base ring having apertures communicating between the valves and said outlets;   d. and a set of distributor tubes are secured in the housing means outlets.   
     
     
        6. A self-flushing valve, comprising: a. means defining an outlet port surrounded by a valve seat;   b. a flap valve element for the valve port formed of elastomeric material;   c. means sealing clamping the flap valve by one margin at one side of the valve seat;   d. the valve element forming adjacent the clamping means on integral hinge element, the hinge element being yieldably biased to hold the valve element on an angular relation to the port to permit flushing flow of fluid between the valve element and valve seat and out the port, the hinge element being yieldable and the valve element being of sufficient area to cooperate with the valve seat so as to create a predetermined pressure differential caused by flushing flow through the port to close upon the valve seat;   e. the valve seat and flap valve element defining therebetween a trickle flow passage operable upon closure of the flap valve element upon the   
     
     
        valve seat element. 17. A self-flushing valve as defined in claim 16, wherein: a. the valve element when closed relative to the other valve seat to produce trickle flow is yieldable to pressure changes to effect corresponding change in the area of the trickle flow passage, thereby tending to produce constant trickle flow of fluid through a range of fluid   
     
     
        pressures. 18. A self-flushing valve, comprising: a. tubular member having an inlet at one end and an outlet at its other end;   b. the tubular member including a plurality of side walls normally disposed in angular relation and joined longitudinally to form alternately, longitudinally extending acute apeces and obtuse apeces and collectively defining an internal flushing passage for fluid communicating between said inlet and outlet;   c. the side wall being resiliently yieldable in response to a predetermined pressure differential between their outer surfaces and inner surfaces to collapse inward into mutually sealing relation;   d. and trickle passage means for fluid formed at their obtuse apeces when the side walls are in their collapsed condition and communicating between   
     
     
        said inlet and outlet. 19. A self-flushing valve as defined in claim 18, wherein: a. the trickle passage means being constrictible in response to increased external pressure to maintain substantially constant flow of fluid therethrough. .Iadd. 20. A self flushing valve for disposition in a fluid passageway, the passageway being subjected periodically to fluid under pressure whereby, on initiation of a pressure period the fluid pressure progressively rises from a minimum pressure to a maximum pressure, and on termination of the pressure period, the fluid pressure progressively falls from its maximum pressure to its minimum pressure, the self flushing valve comprising:   a. valve means including a pair of mutually confronting wall elements normally spaced to form a flush flow passage having a major transverse dimension and a minor transverse dimension, the flush flow passage having a first end forming an entrance end communicating with the fluid passageway and a second end disposed longitudinally therefrom forming an outlet end, the flush flow passage creating on fluid flow therethrough a region or reduced pressure;   b. at least one of the wall elements being formed of elastomeric material having a first surface exposed to fluid pressure in the fluid passageway and a second surface subjected to the region of reduced pressure in the flush flow passage to cause collapse toward the other wall element to close the flush flow passage upon increase of fluid pressure above its minimum pressure;   c. the flexible wall element exerting a counterforce tending to cause separation from the other wall element upon approach of the fluid pressure towards its minimum pressure to cause a final flush flow between the wall elements;   d. and the wall elements including confronting portions forming a trickle passage therebetween upon closure of the flush flow passage for trickle   
     
     
        flow from the fluid passageway to the outlet. .Iaddend. .Iadd. 21.  A self flushing valve comprising: a. means forming a fluid passageway, the passageway being subjected periodically to fluid under pressure whereby, on initiation of a pressure period, the fluid pressure progressively rises from a minimum pressure to a maximum pressure, and on termination of the pressure period, the fluid pressure progressively falls from its maximum pressure to its minimum pressure;   b. valve means including a pair of mutually confronting wall elements normally spaced to form a flush flow passage having a major transverse dimension and a minor transverse dimension, the flush flow passage having a first end forming an entrance end communicating with the fluid passageway and a second end disposed longitudinally therefrom forming an outlet end, the flush flow passage creating on fluid flow therethrough a region of reduced pressure;   c. at least one of the wall elements being formed of elastomeric material having a first surface exposed to fluid pressure in the fluid passageway and a second surface subjected to the region of reduced pressure in the flush flow passage to cause collapse toward the other wall element to close the flush flow passage upon increase of fluid pressure above its minimum pressure;   d. at least one of the wall elements having at least one groove of preselected dimension forming, upon closure of the flush passage, a trickle passage, the trickle passage undergoing constriction as the fluid pressure increases thereby to produce an essentially constant rate of trickle flow through a range of fluid pressure;   e. the flexible wall element exerting a counterforce tending to cause separation from the other wall element upon approach of the fluid pressure towards its minimum pressure to cause a final flush flow between the wall   
     
     
        elements. .Iaddend..Iadd. 22.  A self flushing valve, as defined in claim 21, wherein: a. both wall elements are flexible and mutually collapse toward each other to close the flush passage and form the trickle passage. .Iaddend..Iadd. 23. A self flushing valve, as defined in claim 21, wherein:   a. upon collapse of the flush flow passage, the entrance end of the trickle passage coincides with the entrance end of the flush flow passage. .Iaddend.