Abstract:
A pop-up sprinkler includes an outer housing having an inlet passage and an inlet for connection to a source of pressurized fluid. A riser is mounted in the housing for moving from a normally retracted position to an operative extended position in response to fluid pressure. A pressure responsive inlet valve assembly is mounted in the outer housing adjacent the inlet passage and includes a valve seat and a valve member. The inlet valve assembly further includes a velocity control disc that is biased into engagement with the valve seat. The velocity control disc initially meters inlet fluid for limiting a rate of opening of the valve member for controlling flow of fluid through the inlet and extension of the riser to the extended position. The velocity control disc is made of an elastomeric material and is deflectable radially inwardly to accommodate debris.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to irrigation sprinklers, and more particularly, to an improved velocity control disc for an inlet valve assembly of a pop-up sprinkler. 
     The use of irrigation systems for watering plants where rainfall is inadequate is common throughout the world today. One of the most widely used systems, particularly for lawns and athletic fields, is a sprinkler system wherein a plurality of pop-up sprinklers are positioned about a land area for uniformly distributing water in accordance with a watering program executed by a controller. These sprinklers have a telescoping riser which retracts into a fixed sub-surface housing when not in use. When pressurized water is supplied to the sprinkler, the riser extends or pops-up from the sub-surface housing to eject a stream of water. 
     Sprinklers of this type are widely used on golf courses and other turf applications. These are usually high pressure systems and are frequently subjected to significant forces each time water is supplied to them, particularly when they are supplied with a high pressure combination of air and water. These high forces over a lifetime of use can damage sprinklers and reduce their useful life. The highest forces result when a sprinkler is subjected to surge conditions, such as when the system is being winterized or being refilled with water in the spring. In climates where irrigation systems are subject to freezing, the water must be removed from the system before winter. The water is purged from the system by means of compressed air. The compressed air acts much more rapidly than water and usually results in the risers shooting up rapidly with very high forces resulting in damage to the sprinklers. High surge forces also frequently occur when empty pipes are being filled with water. As the lines are being filled, air or a combination of water and air is forced into each sprinkler and vented through the same. Under these conditions the riser frequently shoots up at a high velocity and is slammed against the stationary outer housing with relatively great force. 
     Attempts to solve this problem by making the sprinklers heavier and stronger have been unsatisfactory because of increased costs. The dual medium of water and air makes unsatisfactory the use of slow opening valves to control the out-flow. 
     Another problem frequently encountered in so-called “valve-in-head” sprinklers is that large particles get trapped between the moving valve member and seat during closing of the valve. This results in continuous leakage until the sprinkler is cycled again. The valve seat can also be damaged. 
     Therefore, there is a need for a means for reducing the extension velocity of the riser of a pop-up sprinkler in order to prolong its life. There is also a need for a valve-in-head sprinkler design that reduces the tendency for large particles to become trapped against the valve seat. 
     Accordingly, it would be desirable that a sprinkler be available having a means for reducing the riser extension velocity to prevent the resultant high forces and consequential damage. It would also be desirable that a sprinkler have some means for reducing the tendency for large particles to become trapped against the valve seat. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     Accordingly, it is a primary object of the present invention to provide a pop-up sprinkler having an improved inlet valve assembly for controlling riser extension velocities and reducing high forces normally resulting therefrom. 
     In accordance with the present invention, a pop-up sprinkler includes an outer housing having an inlet passage and an inlet for connection to a source of pressurized fluid. A riser is in the housing for moving from a normally retracted position to an operative extended position in response to fluid pressure. A pressure responsive inlet valve assembly is mounted in the outer housing adjacent the inlet passage and includes a valve seat and a valve member. The inlet valve assembly further includes a velocity control disc that is biased into engagement with the valve seat. The velocity control disc initially meters inlet fluid for limiting a rate of opening of the valve member for controlling flow of fluid through the inlet and extension of the riser to the extended position. The velocity control disc is made of an elastomeric material and is deflectable radially inwardly to accommodate debris. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects and advantages of the present invention will become apparent from the following description when read in conjunction with the drawings wherein: 
     FIG. 1 is a vertical sectional view of a prior art pop-up sprinkler incorporating a conventional inlet valve assembly; 
     FIG. 2 is an enlarged vertical sectional view showing further details of the inlet valve assembly illustrated in FIG. 1; 
     FIG. 3 is an enlarged fragmentary vertical sectional view showing details of the left half of a preferred embodiment of the inlet valve assembly of the present invention in its closed position; 
     FIG. 4 is a view similar to FIG. 3 showing details of the right half of the inlet valve assembly in its open position; and 
     FIG. 5 is an enlarged fragmentary vertical sectional view of the valve seat and velocity control disc of the inlet valve assembly of FIG. 3 when the inlet valve assembly is in its closed and a piece of grit is lodged against the valve seat and is deflecting the velocity control disc inwardly. 
     Throughout the drawing figures, like reference numerals refer to like parts. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, there is illustrated a conventional pop-up sprinkler  10 . It includes a generally cylindrical tubular outer housing  12  having a threaded inlet  14  at a lower end for mounting to the end of a threaded pipe or the like (not illustrated) connected to a supply line. The supply line is typically a PVC pipe that is connected to a source of pressurized fluid which may be water, air, or a combination of water and air. An upper outlet end of the housing  12  is provided with a split retaining ring  16  detachably mounted in an annular recess  18  for securing a retractably mounted cylindrical tubular inner housing or riser  20 . 
     The riser  20  (FIG. 1) is retractably mounted inside the outer housing  12  for extension upwardly therefrom. The riser  20  includes a nozzle  22  mounted in an upper or outer end thereof for distributing a stream of water therefrom. The nozzle  22  is mounted in a passage or socket  24  in a head  26  that is rotatably driven by means of a turbine  28  through a reduction gear drive train  30 , as more fully described hereafter. 
     The particular sprinkler  10  (FIG. 1) is designed for watering golf courses and playing fields. The nozzle  22  rotates in a partial or full circle about a central vertical axis of the outer housing  12 . A second nozzle  32  is mounted in the head  26  opposite the nozzle  22 . The nozzle  32  communicates via a port  34  with a through passage  36  to improve the distribution of the stream of water closer in to the sprinkler  10 . 
     The riser  20  (FIG. 1) is retractably mounted within a bore  38  of the outer housing  12 , and is oriented by a plurality of circumferentially spaced internal ribs  40  and by means of teeth  42  on radial flange  44  at the lower end thereof An elongated coil compression spring  46  engages a shoulder or flange  44  at the lower end of the riser  20 , and is confined within the bore by means of the retaining ring  16  at the upper end. The riser  20  is normally biased by the coil spring  46  to its lowermost or retracted position, as illustrated in FIG. 1, when the water pressure is shut off. The spring  46  is positioned between the annular flange  44  and a ring  48  at the upper end of the housing  12 , which biases against an outer annular seal assembly  50  retained in position by the retaining ring  16 . 
     The riser  20  (FIG. 1) carries the rotating head  26  from its retracted position in the outer housing  12  to an extended position above the ground surface where the head  26  rotates and distributes water. The riser  20  converges at the top with inwardly tapering walls to an opening  52  in which is rotatably mounted a tubular shaft  54 , having an upper end extending above the upper end of housing  20  and upon which the rotating head  26  is mounted. The shaft  54  serves to mount the head  26  to convey water from the inlet  14  to the outlet nozzles  22  and  32 . The shaft  54  also transfers torque from the gear drive train  30  to the rotating head  26 . 
     The driving assembly for rotating the head  26  is mounted in the riser  20  and includes support structure  56  having a journal  58  in which the lower end of the tubular shaft  54  is rotatably mounted. A shoulder surrounds the opening  52  and is engaged by a shoulder on rotary shaft  54 . 
     The turbine  28  rotates in response to water flowing upwardly through the sprinkler  10 . The turbine  28  is mounted on a shaft  60  which drivingly rotates a pinion gear which meshes with and drives a reduction gear unit  62  having a larger driven gear and a smaller pinion gear. The reduction gear unit  62  further drives a reduction gear  64  which in turn drives a reduction gear unit  66  further driving a reduction gear  68 . The reduction gear  68  is the final drive component in the reduction drive gear train  30 . The gear  68  meshes with a gear  70  on a shaft  72  for driving a pinion  74  which in turn drives an internal ring gear  76  which drives the tubular shaft  54 . inlet valve assembly  80  (FIG. 1) is mounted inside the lower end of the outer housing  12  adjacent the inlet  14  and controls fluid entering the sprinkler  10 . The valve assembly  80  also functions as a check valve in that it prevents back flow. The valve assembly  80  comprises a housing  82  (FIG. 2) which may or may not be integral with the outer housing  12 . The housing  82  is shown as a separate insert in FIG.  2 . The housing  82  is of a generally cylindrical configuration and is positioned coaxially within the bore of outer housing  12  adjacent the inlet  14 . The housing  82  includes an outer cylindrical wall  84  having an internal bore  86  in which a generally cylindrical valve member  88  is reciprocally mounted. 
     The valve member  88  (FIG. 2) has a generally cylindrical configuration including a circular face  90  (FIG. 1) on which is mounted an elastomeric valve seal  92  (FIG. 2) for sealingly engaging an annular valve seat  94  surrounding the inlet  14 . The valve member  88  is reciprocally mounted in the bore  86  by means of an annular seal  96  and guided by a plurality of ribs  98 . An annular retainer ring  100  threadably mounts to the interior of the valve seal  92  and retains the seal  96  in place. A coil-type spring  102  normally biases the valve member  88  to its closed or seated position as shown in FIGS. 1 and 2. 
     The valve member  88  (FIG. 2) closes the bore  86  forming a closed chamber  104  which is normally pressurized to maintain the valve member  88  in its closed or seated position. A rivet  106  engages a retaining and strainer washer disc  108  which engages and retains the valve seal  92  on the face of the valve member  88 . Pressurized fluid from the inlet  14  flows very slowly past slots in the edge of disc  108  via a tortuous passage through the face  90  of valve member  88  into chamber  104  and maintains the valve member  88  in its normally closed position. Further details of this construction are described in U.S. Pat. No. 5,979,863, of Bradley M. Lousberg, granted Nov. 9, 1999, entitled, “Irrigation Control Valve and Screen”, the entire disclosure of which is specifically incorporated herein by reference. 
     The chamber  104  is vented via a passage  110  (FIG. 2) in the housing  82  and an outlet  112  in the outer housing  12  by a remotely controlled solenoid or hydraulically actuated valve (not shown). The outlet  112  is connected to the solenoid or hydraulically actuated valve by a hose  114 . This venting enables inlet fluid to open the valve member  88 . When the valve member  88  is in its raised open position, water from the inlet  14  can flow radially outwardly past the valve seat  94  and through flow passages between circumferentially spaced ribs  116 . When the incoming fluid is air or a mixture of air and water, the valve member  88  may open rapidly causing a very rapid extension of the riser  20 , which may damage the sprinkler  10 . 
     In accordance with the present invention, the sprinkler  10  has a modified inlet valve assembly  120  illustrated in FIG.  3 . An elastomeric velocity control disc  122  is mounted in overlapping fashion concentric with the circular base  124   a  of a cylindrical valve member  124 . A lower valve metering assembly  126  surrounds a metal metering rod  127 . The velocity control disc  122  is sandwiched between the lower valve metering assembly  126  and the circular base  124   a  of the valve member  124 . The valve member  124  is supported for vertical reciprocation by a flexible elastomeric hinge valve member  128 . The radially inward lip  128   a  of the hinge valve member  128  is held against the upper circular edge of the valve member  124  by the wrap-around upper annular edge of a cylindrical mounting cup  130 . The radially outward lip  128   b  of the hinge valve member  128  is clamped between a lower cylindrical retainer  132  and an upper cylindrical cover member  134 . The upper end of the metering rod  127  is snugly received inside a socket  136  integrally formed on the underside of the cover member  134 . A plurality of radially, extending, circumferentially and axially spaced fins  140  connect the cover member  134  to a circular rim  142  held in place in the outer housing  12  by a split snap ring  144 . The fins  140  center the cover member  134 . The spaces between the fins  140  define major flow paths for water flowing from the inlet  14  past the valve seat  94  when the inlet valve assembly  120  is in its raised open position illustrated in FIG.  4 . The lower retainer  132  and upper cover member  134  have inclined opposing walls that form a region with a V-shaped cross-section for limiting upper and lower movement of the central flexible web  128   c  of the elastomeric hinge valve member  128 . The upper end of a coil spring  146  surrounds a cylindrical shoulder  148  integrally formed on the underside of the cover member  134 . The lower end of the coil spring  146  engages the flat bottom wall of the mounting cup  130  to bias the inlet valve assembly  120  to its closed position illustrated in FIG.  3 . 
     An upper pressure chamber  150  (FIG. 3) in the inlet valve assembly  120  is selectively vented via passage  152  (FIG. 4) through a C-shaped hose  154  terminating in a barbed fitting  156 . The barbed fitting  156  is connected via another hose (not illustrated) to a solenoid actuated or hydraulically actuated pilot valve (not illustrated). 
     The velocity control disc  122  (FIG. 3) has a generally disc shaped configuration with a serpentine cross-section. The velocity control disc  122  has a radially inwardly tapered outer peripheral wiper  122   a  (FIG. 5) that engages (or provides a close fit with) the wall of the valve seat  94  and the passage leading to the inlet  14  to meter the incoming air and/or water during initial opening of the inlet valve assembly  120 . This results in a slower pop-up stroke of the riser  20  and/or a lower impact at the end of its stroke. The velocity control disc  122  also acts to strain relatively large debris particles such as  160  during closing as the velocity control disc  122  can deflect radially inwardly and keep the debris particle  160  from being trapped between the velocity control disc  122  and valve seat  94 . The valve member  124  has a radially inwardly tapered wall  124   b  that normally provides a gap between the velocity control disc  122  and the valve member  124 . This gap is visible in FIGS. 3 and 4. The gap disappears when the large debris particle  160  (FIG. 5) pushes the outermost portion of the velocity control disc  122  inwardly. 
     In operation, when a fluid such as air and/or water is supplied under high pressure to the inlet of the sprinkler  10  and the chamber  150  (FIG. 3) is vented. The inlet fluid acts against the lower face of the inlet valve assembly  120  to force it away from the seat  94 . Fluid initially begins flowing around the peripheral edge of the velocity control disc  122  and is initially metered, resulting in a slower opening of the valve member  124  and a slower flow of fluid into the sprinkler  10 . This results in a slower movement of the riser  20  to its extended position and lessens the resulting impact force when the coil spring  46  (FIG. 1) reaches the end of its compression. The velocity control disc  122  thus serves as a metering or damping means. When the inlet valve assembly  120  is being closed or shut down after a run cycle of the sprinkler  10 , the elastomeric velocity control disc  122  extends into the inlet passage immediately upstream of the female threaded inlet  14 . The velocity control disc  122  begins metering the water and forcing it at high across the valve seat  94 . This flushes debris such as the particle  160  away from the seat  94  to insure a more complete seal. The disc  122  also deflects or deforms to prevent damage to the valve seat  94  by the debris particle  160 . The velocity control disc  122  may have notches around its peripheral edges, as shown in FIG. 5 of my U.S. Pat. No. 5,927,607. This provides additional fluid bleed. 
     While I have illustrated and described my invention by means of specific embodiments, it should be understood that numerous changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the appended claims: