Abstract:
A sprinkler includes an outer case and a riser mounted for reciprocation within the case. The riser supports a nozzle, an impeller, and a drive linkage connecting the nozzle and the impeller. A diaphragm valve is mounted in outer case beneath the riser and includes a valve member vertically reciprocable within a valve support housing to engage and disengage a valve seat. The valve seat can reciprocate relative to the valve support housing to reduce mechanical loading.

Description:
FIELD OF THE INVENTION 
   The present invention relates to sprinklers used to irrigate lawns, gardens and landscaping, and more particularly, to so-called valve-in-head sprinklers that have built in valves for turning ON and OFF the application of water by the sprinkler. 
   BACKGROUND 
   Irrigation systems used in homes typically comprise a garage-mounted electronic controller that selectively turns a plurality of solenoid actuated valves ON and OFF in accordance with a pre-programmed watering schedule. The valves admit water to subterranean PVC pipes having several spray, rotor-type or drip-type sprinklers attached to the pipes at spaced intervals. The solenoid actuated valves are usually housed together in a plastic valve box buried near the electronic controller. 
   In some environments, such as golf courses, so called “valve-in-head” sprinklers are preferred. They have a diaphragm valve built into the lower end thereof which is typically actuated by a solenoid mounted in the sprinkler itself that opens and closes a pilot valve. Each valve-in-head sprinkler on a golf course can thus be individually actuated by an electronic controller usually mounted a considerable distance away. 
   In U.S. Pat. No. 6,491,235 of Scott et al., assigned to Hunter Industries, Inc., there is disclosed a valve-in-head sprinkler that has a top serviceable diaphragm module. The diaphragm valve module can be readily replaced without excavation and removal of the entire sprinkler if the diaphragm valve module is worn, damaged by grit or otherwise defective, e.g. if there is leakage from the top of the outer sprinkler case when the valve is in its OFF state. The telescoping riser that contains the nozzle, turbine and gear drive train is first removed from the outer sprinkler case. The diaphragm valve module, which is mounted in the lower end of the outer sprinkler case, can then be withdrawn and replaced. 
   Valve-in-head sprinklers typically operate at a relatively high pressures, e.g. over one hundred PSI, and in some cases as high as two hundred PSI. When the valve is in its  CLOSED  or turbine state such high water pressures place substantial strains on the mechanical components which can lead to failures. It would be desirable to have an improved replaceable valve module for a valve-in-head sprinkler that alleviates this problem. 
   SUMMARY OF THE INVENTION 
   In accordance with an embodiment of the invention, a sprinkler includes an outer case and a riser mounted for reciprocation within the case. The riser supports a nozzle, an impeller, and a drive linkage connecting the nozzle and the impeller. A diaphragm valve is mounted in outer case beneath the riser and includes a valve member vertically reciprocable within a valve support housing to engage and disengage a valve seat. The valve seat can reciprocate relative to the valve support housing. 
   In accordance with another embodiment of the invention a valve module for a sprinkler includes a valve support housing including a cap portion. A valve seat is connected to the valve support housing for reciprocation toward and away from the valve support housing. A valve member is reciprocable within the support housing to engage and disengage the valve seat. A diaphragm is mounted in the valve support housing and has an outer periphery connected to the valve support housing and an inner periphery connected to the valve member. A pilot hole passage is provided for venting fluid from a chamber between the diaphragm and the cap portion to permit the valve member to move between a  CLOSED  position in which the valve member is engaged with the valve seat and an OPEN position in which the valve member is disengaged with the valve seat. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a part vertical section, part side elevation view of a valve-in-head sprinkler with a replaceable valve module in accordance with an embodiment of the present invention. 
       FIG. 2  is an enlarged side elevation view of the valve module of the sprinkler of  FIG. 1  illustrating its valve in an OPEN state. 
       FIG. 3  is an enlarged side elevation view of the valve module of the sprinkler of  FIG. 1  illustrating its valve in an  CLOSED  state. 
       FIG. 4  is an enlarged vertical sectional view of the valve module of the sprinkler of  FIG. 1  illustrating its valve in an OPEN state. 
       FIG. 5  is a vertical sectional similar to  FIG. 4  illustrating the valve of the module in a  CLOSED  state. 
       FIG. 6  is an enlarged bottom plan view of valve module of the sprinkler of  FIG. 1 . 
   

   DETAILED DESCRIPTION 
   The entire disclosure of U.S. Pat. No. 6,491,235 granted Dec. 10, 2002 to Scott et al. is hereby incorporated by reference. Referring to  FIG. 1 , a valve-in-head rotor type sprinkler  10  includes a valve actuator component assembly  12  and a top serviceable diaphragm valve module  14 . The valve module  14  is mounted in the lower end of a generally cylindrical outer case  16  having a female threaded inlet  18 . A tubular riser  20  is vertically reciprocable within the outer case  16  when the valve module  12  is opened and closed. A cylindrical nozzle head or turret  22  is rotatably mounted at the upper end of the riser  20 . The riser  20  is held in its retracted position by a coil spring  23  held in place by an upper snap ring  24 . A turbine (or other impeller such as a ball drive), gear reduction, and reversing mechanism (not visible) are mounted in the riser  20  and rotate the nozzle turret  22  through an adjustable arc, as well known in the art. A lower snap ring  26  releasably holds the valve module  20  in position within the lower end of the outer case  16 . 
     FIGS. 2-6  illustrate details of the valve module  14 . The valve module  14  includes a generally cylindrical upper valve support housing  28  and a lower valve seat support basket  30  connected to the underside of the upper valve support housing  28 . The valve seat support basket  30  is formed with a frusto-conical filter screen  32  at its lower end. A cylindrical upper section  34  of the valve support basket  30  has an upper end that forms a valve seat  36 . An O-ring  38  made of suitable elastomeric material provides a seal between the valve seat support basket  30  and a shoulder  40  ( FIG. 1 ) of the outer case  16 . 
   A cylindrical piston valve member  42  is vertically reciprocable within the support housing  28 . A horizontally extending valve disk member  44  made of suitable elastomeric material extends across the lower end of the piston valve member  42  and its peripheral edge is moved into and out of sealing engagement with the valve seat  36 . The piston valve member  42  slides up and down through a circular aperture in a guide member  46 . The outer periphery of a flexible elastomeric diaphragm  48  is locked between the guide member  46  and a generally dome-shaped cap portion  50  of the valve support housing  28 . The inner periphery of the diaphragm  48  is locked between the inner and outer sections of the piston valve member  42 . A coil spring  52  is captured between the center of the cap portion  50  and the bottom of the inner section of the piston valve member  42  to bias the piston valve member to its lower  CLOSED  position illustrated in  FIG. 5 . A metering pin  54  extends through a metering plate assembly  56  attached to the underside of the piston valve member  42 , overlying the valve disk member  44 . The metering pin  54  extends axially through the center of the piston valve member  42  and its upper end is captured in a socket  58  formed in the underside of the center of the cap portion  50 . All of the components of the diaphragm valve module  14  are removable as unit from the upper end of the outer case  16  upon removal of the riser  20  which requires removal of the snap rings  24  and  26 . 
   The valve actuator component assembly  12  ( FIG. 1 ) can be actuated to vent water from the chamber  60  ( FIG. 5 ) between the upper side of the diaphragm  48  and the cap portion  50  through a pilot hole passage  61   a  ( FIG. 4 ) connected via tube  61   b  ( FIG. 1 ). The piston valve member  42  then moves from its lower  CLOSED  position illustrated in  FIG. 5  to its upper OPEN position illustrated in  FIG. 4 . This disengages the valve disk member  44  from the valve seat  36  allowing water to flow through the inlet  18 , through the filter screen  32  and out of the valve support basket  30 . When the water leaves the valve seat support basket  30  it flows between four circumferentially spaced (ninety degrees apart) vertically extending ribs  62  of the valve seat support basket  30  and through a plurality of circumferentially spaced flow passages  63  ( FIG. 6 ). This water then flows into the open lower end of the riser  20  and exits from the nozzle turret  22  in an inclined stream. 
   The valve seat support basket  30  ( FIGS. 2-5 ) is loosely connected to the valve support housing  28  so that the valve seat  36  can reciprocate vertically relative to the valve support housing  28 . By way of example only, the amount of reciprocation of the valve seat support basket  30  may be less than five millimeters. This greatly reduces the mechanical stress and loading on the ribs  62  and other components of the diaphragm valve module  14  when the diaphragm valve module  14  is in its closed or OFF state illustrated in  FIGS. 3 and 5 . The valve seat support basket  30  is connected to the upper valve support housing  28  by a retaining ring  64  ( FIG. 6 ) with four flanges  64   a  having apertures that slide vertically over four circumferentially spaced vertical retaining posts  66 . The retaining posts  66  vertically extend from the underside of the valve support housing  28 .  FIG. 4  illustrates the slightly raised position of the valve seat support basket  30  when the diaphragm valve module  14  is in its OPEN state.  FIG. 5  illustrates the slightly lowered position of the valve seat support basket  30  when the diaphragm valve module  14  is in its  CLOSED  state. The lower ends of the retaining posts  66  are swaged to provide a flare  68  ( FIGS. 2 and 6 ) to keep the retaining ring  64  from becoming detached from the valve support housing  28 . 
   The four retaining posts  66  retain the valve support basket  30  in a manner such that the valve support basket  30  is not under spring tension when the diaphragm valve module  14  is not yet installed in the outer case  16 . This prevents stress on the ribs  62 , retaining ring  64  and retaining posts  66 . The valve seat  36  is capable of independent movement relative to the valve support housing  28  so that the closing forces generated by the piston valve member  42  do not apply unwanted loading on the various components of the valve support basket  30  under relatively high water pressures, e.g. over one hundred PSI. When the diaphragm valve module  14  goes to its  CLOSED  state, the valve support basket  30  is forced downwardly until it stops against the upper end of shoulder  40  ( FIG. 1 ). The valve support housing  28  in turn moves upwardly until it stops against the underside of lower snap ring  26 . The top of the valve support housing has projections (not visible) that lock the lower snap ring  26 , providing a safety feature to prevent unsafe removal of the lower snap ring  26  when the sprinkler  10  is pressurized. The ability of the valve support basket  30  to reciprocate downwardly when the pressurized water to the sprinkler  10  is turned OFF allows the lower snap ring to be unlocked and removed. 
   While we have described an embodiment of the present invention, it should be understood that the sprinkler and diaphragm valve module can be modified in both arrangement and detail. For example, our invention can implemented in a valve-in-head sprinkler that does not have a removable diaphragm valve module. Therefore, the protection afforded our invention should only be limited in accordance with the scope of the following claims.