Abstract:
A safety valve for a lawn sprinkler system having at least one subterranean flow line and at least one head for spraying irrigation water. The valve includes a tubular member connected between the flow line and the head. The tubular member has an axial passage therethrough for the flow of water from the flow line to the head. A seat is located within the passage. A ball is located in the passage upstream of the seat. The ball is axially movable from an open position upstream of the seat to a closed position in engagement with the seat if the water flowing through passage reaches a selected flow rate. A coiled spring in the passage is in engagement with the ball for urging the ball toward the open position

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates in general to valves for water lines, and particularly to a safety valve for a water sprinkler system that stops the flow in the event of a malfunction.  
       BACKGROUND OF THE INVENTION  
       [0002]     A typical lawn sprinkling system has lateral flow lines buried in various parts of the lawn, plant beds, and the like. One or more risers or sprinkler heads connect to each lateral flow line and extend upward to level at or above the surface of the ground. The sprinkler heads include types that pop up when supplied with water pressure as well as types that are stationary and have orifices located above the ground.  
         [0003]     A solenoid operated valve is connected to the various flowlines for selectively applying water pressure for a timed interval. A controller controls the solenoid valve to automatically supply water pressure. The user can adjust the days for watering as well as the duration of timed intervals and the particular flow lines to receive water pressure.  
         [0004]     If one of the heads breaks, an excessive amount of water will flow through the broken head for each timed interval. Because the controller is automatic and the owner not always present during watering intervals, the owner may not realize for some time that the head is broken. Various patents disclose devices to remedy excessive water discharge in the event of a sprinkler head breakage, but improvements are desired. For example, the safety valve member in some of the devices is located above ground in the riser. Typically, a failure is caused by breakage of the riser, and in these types of devices, the safety valve must be replaced after one failure.  
       SUMMARY OF THE INVENTION  
       [0005]     In this invention, a flow line safety valve installs between the flow line and the outlet. The valve comprises a tubular member having a passage therethrough for the flow of fluid from the flow line. A seat located within the passage. A valve element is located in the passage upstream of the seat. The valve element is movable from an open position upstream of the seat to a closed position in engagement with the seat if the fluid flowing through passage reaches a selected flow rate. A spring biases the valve element toward the open position. If the flow rate increases above a selected maximum due to a malfunction, the flow pressure on the valve element causes the valve element to overcome the force of the spring and move to the closed position.  
         [0006]     In one embodiment, the valve element is attached to the spring so as to place the spring in tension when moving to the closed position. In another embodiment, the valve element places the spring in compression when moving to the closed position.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  is a vertical sectional view of a first embodiment of a safety valve in accordance with this invention shown installed with a sprinkler head.  
         [0008]      FIG. 2  is a view of the valve and sprinkler head of  FIG. 1 , showing the sprinkler head in an operational position.  
         [0009]      FIG. 3  is a sectional view of the sprinkler head and valve of  FIG. 1 , showing the orifice member removed and the valve in a closed position.  
         [0010]      FIG. 4  is a sectional view of the safety valve of  FIG. 1  taken along the line  4 - 4  of  FIG. 1 .  
         [0011]      FIG. 5  is a top view of an alternate embodiment of a safety valve in accordance with this invention.  
         [0012]      FIG. 6  is a sectional view of the valve of  FIG. 5 , taken along the line  6 - 6  of  FIG. 5 .  
         [0013]      FIG. 7  is a sectional view of the valve of  FIG. 6 , taken along the line  7 - 7  of  FIG. 5 .  
         [0014]      FIG. 8  is a sectional view of the valve of  FIG. 5 , taken along the line  8 - 8  of  FIG. 6 .  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]     Referring to  FIG. 1 , a sprinkler assembly  11  is schematically shown with a safety valve  13  constructed in accordance with this invention. Sprinkler assembly  11  may be of a number of different types and designs, and the particular one shown is for example only. Sprinkler assembly  11  includes a “T” or flow line junction  15  that connects into a buried water sprinkler flow line (not shown). Water pressure will be present in flow line junction  15  only when a remote solenoid valve (not shown) actuates to allow water flow. A remote controller (not shown) turns on and off the various solenoid valves. The user can adjust the controller to select the intervals between watering cycles, the duration of each watering cycle, and which flow line or circuit is to receive water pressure. Flow line junction  15  has an upward facing receptacle  17  which may have a threaded upper end.  
         [0016]     Safety valve  13  has a tubular body  19  that secures to receptacle  17 , such as by threads. A retainer  21  is mounted within a central bore  22  in body  19 . As illustrated in  FIG. 4 , retainer  21  in this example comprises a pair of thin rods mounted perpendicular to each other and to the side wall of bore  22 . Rods  21  define apertures to allow water to pass through. Retainer  21  could be of a variety of types other than rods, such as a plate containing apertures.  
         [0017]     A coil spring  23  has an upstream end secured to retainer  21  on the longitudinal axis of body  19 . Coil spring  23  is normally in its natural state, not in tension. The upper end of coil spring  23  is secured to a ball  25 . Ball  25  is of a rather firm elastomeric material in the preferred embodiment.  
         [0018]     A downward facing seat  27  is formed in the upper end of body  19 . Seat  27  is generally conical or a portion of a sphere for sealing when contacted by ball  25 . Ball  25  will be located below seat  27  when no water pressure is present in junction  15 . When water pressure is present, as shown in  FIG. 2 , and if the water flow through seat  27  is less than a selected flow rate, ball  25  will still be located below seat  27  because of the force of spring  23 . If the water flow rate through seat  27  exceeds the selected maximum, as shown in  FIG. 3 , ball  25  will stretch spring  23 , contact seat  27  and prevent flow through seat  27 .  
         [0019]     A conventional sprinkler head mounts to the downstream end of safety valve body  19 . For example, the sprinkler head may include a riser  29  that secures to the upper end of safety valve body  19 , preferably by threads. In the prior art, riser  29  would normally secure to receptacle  17 . However in this invention, safety valve  13  locates between riser  29  and receptacle  17 . Riser  29  could be integrally formed with valve body  19 . Riser  29  is a tubular member having an upper end that may be flush with ground level  30  for lawn areas that are mowed, or optionally riser  29  may extend above ground  30 , particularly if located in flower gardens or adjacent bushes. Safety valve  13  will normally be located below ground.  
         [0020]     A cap  31  secures to the upper end of riser  29 , normally by threads. Cap  31  has a tubular inner seal member  33  extending downward and concentrically located within the inner diameter of riser  29 . Seal member  33  is shown as being integrally formed with cap  31 , however it may be formed of a softer material and joined to cap  31 . Seal member  33  may include an O-ring or other type of seal. In this embodiment, seal member  33  has an internal tapered surface located on its lower end for serving as a seal.  
         [0021]     An extension tube  35  is slidably carried within riser  29  in this example. Extension tube  35  is a tubular member with a side wall that fits closely within the inner diameter of seal member  33 . Extension tube  35  has a radially extending flange  37  on its lower end. A fillet is formed between flange  37  and the cylindrical portion of extension tube  35  for mating with the tapered surface on seal member  33  while in the upper position shown in  FIG. 2 . A coil spring  39  encircles extension tube  35  and biases extension tube  35  downward. Coil spring  39  has an upper end that engages cap  31  and a lower end that engages flange  37 .  
         [0022]     An orifice member  41  is located on the upper end of extension tube  35 . In this example, orifice member  41  is secured by threads to extension tube  35 , but it could be integrally formed. Orifice member  41  has an orifice  43  that has a selected circumferential pattern for directing a spray outward in a desired direction. For example, orifice  43  may extend 45 degrees, 90 degrees, 180 degrees or other amounts. Also, orifice members  41  with adjustable orifices  43  are available.  
         [0023]     In operation, with no water pressure present in flow line junction  15 , sprinkler assembly  11  will appear as shown in  FIG. 1 . Ball  25  will be spaced below seat  27 . Extension tube  35  will be in its lower position. When a remote solenoid valve (not shown) opens, water pressure enters junction  15  and acts against extension tube  35 , pushing it upward to the upper position shown in  FIG. 2 . The water pressure will compress coil spring  39 , and flange  37  will abut and seal against seal member  33 . Because of the small flow area of orifice  43  relative to the inner diameter of seat  27 , the flow of water will not be sufficient to cause ball  25  to rise and seal against seat  27 . The water flows past retainer  21 , through seat  27  and out orifice  43 . The tension of spring  23  is selected to prevent ball  25  from contacting seat  27  unless the flow rate exceeds a selected maximum.  
         [0024]      FIG. 3  illustrates sprinkler assembly  11  in a malfunctioned condition. In this example, orifice member  41  has detached itself from extension tube  35  for one reason or another. Alternately, other malfunctions could exist, such as extension tube  35  cracking or breaking, which otherwise would allow substantial flow out through other portions of sprinkler head  11  rather than orifice  43  ( FIG. 2 ). When the remote solenoid valve (not shown) turns on the water pressure, normally the water would flow out the extension tube  35  at a much higher rate than the normal flow rate through orifice  43 . Unless the owner observes the malfunction, excessive water would be dispensed through the broken sprinkler assembly  11 , and other sprinkler assemblies on the same circuit would possibly lack sufficient pressure to properly work.  
         [0025]     Safety valve  13  avoids this occurrence, because the high flow rate of water will overcome the force of spring  23 , and push ball  25  up into sealing engagement with seat  27 . Ball  25  will prevent any water flow through extension tube  35  when sealed, enabling the remaining sprinkler heads on the same circuit to operate normally. When the water pressure is removed, ball  25  will return to its lower position shown in  FIGS. 1 and 2 . Ball  25  will again seal against seat  27  when water pressure is again returned. This will continue until the malfunctioning sprinkler assembly  11  is detected and repaired or replaced. Safety valve  13  can be re-used with the replacement sprinkler assembly  11 .  
         [0026]     Although shown utilizing a spring  23  that relies on tension to restrain ball  25 , a compressive spring could alternately be utilized to prevent ball  25  from sealing unless the flow rate exceeds a certain level as shown in the embodiment of  FIG. 5-8 . Safety valve  45  comprises a tubular member having an upper body  47  and a lower body  49  secured together, such as by threads, an adhesive, sonic welding, or other means. Lower body  49  has a threaded end  51  for securing to a flow line, such as flow line  15  ( FIG. 1 ). Upper body  53  has a threaded receptacle  53  for connection to a sprinkler head assembly, such as riser  29  ( FIG. 1 ). In the embodiment shown, upper body  47  has flats formed on its exterior for receiving a wrench to secure safety valve  45  between a flow line and a sprinkler head. An axial passage  55  extends through bodies  47 ,  49 .  
         [0027]     A partition  57  is formed in upper body  53  within passage  55 . An inner tube  59  is molded integrally with or otherwise joined to partition  57  and extends downwardly or in an upstream direction. Inner tube  59  is smaller than the inner diameter of upper body  47  at that point. An annular recess  61  in partition  57  extends around inner tube  59 .  
         [0028]     A coiled spring  63  has an upper or downstream portion that locates in annular recess  61 . Spring  63  encircles inner tube  59  and protrudes past inner tube  59  in an upstream direction. A valve element, such as ball  65 , is carried in axial passage  55  for axial movement between a closed position and an open position. In the closed position, ball  65  seals against the open lower end of inner tube  59 , that serves as a seat. In an open position, ball  65  is spaced below the open end of inner tube  59 , as shown in the position shown in  FIGS. 6 and 7 . Spring  63  engages ball  65 , urging it toward the open position. In this embodiment, spring  63  is smaller in diameter than ball  65 . With no water flowing through passage  55 , ball  65  will rest on an upward facing shoulder  69  in lower body  49 .  
         [0029]     As shown in  FIGS. 6 and 7  a plurality of guide ribs  67  extend inward from the inner surface of upper body  47 . Guide ribs  67  extend axially from partition  57  to the lower end of upper body  47 . Guide ribs  67  are spaced apart from each other and located circumferentially around ball  65 . The diameter circumscribed by the interior surfaces of guide ribs  67  is slightly greater than the diameter of ball  65 .  
         [0030]     Referring to  FIGS. 5 and 7 , upper body  47  may optionally have cavities  71  formed therein for strengthening upper body  47 . Preferably bodies  47 ,  49  are formed of plastic, and ball  65  is of an elastomeric material, such as nitrile rubber. Ball  65  is preferably not buoyant in water.  
         [0031]     In the operation of the second embodiment, when the controller (not shown) supplies water pressure to passage  55 , the water will flow around ball  65  and through inner tube  59  to the sprinkler head (not shown), as indicated by the arrows in  FIGS. 6 and 7 . If the sprinkler head functions properly, the flow rate will not be high enough to overcome the force of spring  63 , causing ball  65  to remain generally in the position shown in  FIG. 6 . Because of the spherical shape of ball  65  and the clearances around ball  65  while in the open position, the pressure drop during normal operation is not significant. When the timed duration elapses, the water pressure stops and ball  65  drops to a position resting on shoulder  69 .  
         [0032]     If the sprinkler head is broken, the flow rate will be higher. The pressure of the water is sufficient to overcome the force of spring  63  and push ball  65  to the closed position in sealing engagement with the lower end of tube  59 . This engagement completely blocks further water flow. Ball  65  will remain in that position until the timed interval is over and the water pressure removed by the controller. If the sprinkler head has not been replaced or repaired by the time of the next watering cycle, the water pressure will again cause ball  65  to move into sealing engagement with the lower end of tube  59 . Ball  65  will block flow each time water pressure is supplied to safety valve  45  until the sprinkler head is repaired or replaced.  
         [0033]     The invention has significant advantages. The safety valve moves to a closed position completely blocking water flow when an excessive flow rate is detected. If a sprinkler head breaks, the safety valve avoids wasting water. The safety valve resets itself with each subsequent watering cycle. The safety valve can be installed at any attitude or angle, other than just vertical. The safety valve can be re-used with a new sprinkler head that replaces a broken one.  
         [0034]     While the invention has been shown in only one of its forms, it should be apparent to those skilled in the art that it is not so limited but is susceptible to various changes without departing from the scope of the invention. For example, rather than a separate coiled spring in the first embodiment, the bias member could be an elastic strap integrally formed with the ball. The safety valve may be useful for flow lines other than sprinklers, such as the water lines to clothes washing machines.