Abstract:
The invention is directed to a sprinkler body having a side inlet and improved strength and durability. The side inlet is reinforced with additional structure at a cylindrical wall defining the side inlet. The structure may include a reinforcement rib located within the sprinkler body and intersecting the side inlet. The structure may include a plate located within the cylindrical wall, and the plate may include a collar and/or a crosspiece spanning the side inlet. The structure permits passage of water therethrough and serves to reinforce localized weakened portions or stress concentrators of the side inlet or the sprinkler body.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention is directed to a sprinkler housing having a side inlet and, in particular, to a sprinkler body having a side inlet with improved durability.  
       BACKGROUND OF THE INVENTION  
       [0002]     Irrigation systems utilize a series of pipes or conduits for conveying water from a water source to a series or network of water emitters or sprinklers. Though at one time metallic pipes were used, these suffered from exterior rust and corrosion, as well as interior fouling, and carried a high materials expense. Coatings were developed which promoted the life of metallic pipes, and the use of large diameter pipes helped alleviate the problems with interior fouling. However, cost remained an issue until polymeric piping was developed.  
         [0003]     Polymer or plastic piping offered additional benefits. For instance, threading and sealing of plastic joints is simpler and more reliable. One drawback to plastic piping has traditionally been its strength, particularly in localized regions containing stress concentrators or non-uniform mechanical properties.  
         [0004]     A common irrigation component is a sprinkler utilizing a pop-up spray head. This type often includes a deflector plate secured to a base assembly coupled to a riser or other tube. The riser is received within a sprinkler body that is typically stationary and buried in the ground with a generally vertical orientation. In this manner, the riser and spray head may move between an extended and elevated position relative to a sprinkler body and a retracted and lower position where the riser is substantially received within the sprinkler body. When extended, the spray head is positioned above the ground level to water the surrounding area.  
         [0005]     The length of the sprinkler body is typically dependent on the riser length. That is, a typical sprinkler body with a length of 4 inches may be coupled with a riser having a length of 2 inches, while another sprinkler body of 16 inches may be used with a 12 inch riser. In relatively shorter forms of the sprinkler body, the water may be received from the water source at a lower end of the sprinkler body. However, relatively longer forms for the sprinkler body usually require a side inlet. This may also vary depending on the irrigation application.  
         [0006]     Though much plastic piping can be formed as a continuous length by extrusion, for instance, other components to the irrigation system are made by injection molding. Injection molding often leads to non-uniform mechanical properties, such as a weakened point or weakening feature referred to as a knit line. Specifically, thermoplastic polymers flow at a rate dependent on their temperature. The polymeric materials are typically forced into a mold with a temperature lower than that of the plastic. Therefore, the plastic begins to cool on contact. This cooling is most pronounced at the leading edge of the injection flow, and the leading edge begins to solidify and develop a surface texture as it flows through the mold. When two leading edges meet, a visible line referred to as a knit or mold line is formed. It is known that the plastic material localized at the knit line does not tend to form as strong a bond because the polymer strands do not join and flow as well. Therefore, the knit line does not bond as well and tends to be more brittle. Though the sprinkler bodies maybe reinforced with fibers such as fiberglass, these fibers do not often cross the knit line weld interface, so the knit line does not realize the benefits of the presence of the fibers. Therefore, the knit line typically weakens the piping.  
         [0007]     One example of a component made with such a process is the sprinkler body having a side inlet. Because the geometry of a sprinkler body does not lend itself to extrusion molding, injection molding tends to be more practical to construct the body and the side inlet, as well as a short cylindrical wall that typically surrounds the inlet. From a manufacturing standpoint, principal injection techniques for forming such a sprinkler body often result in the knit line being coincident with or bisecting the side inlet and the cylindrical wall.  
         [0008]     In service, it is not uncommon for the sprinkler body to be filled with water even when the spray head is not presently emitting water. Prior to an off season, the sprinkler is cleared with air so that water does not freeze within the system, which would otherwise cause potentially catastrophic damage. Otherwise, in the absence of some type of bleed control for releasing pressure, the sprinkler body contains a full, static volume of water. In order to activate the sprinkler, the water source is opened such that a pressure surge is applied to the system, thereby forcing water through the system, raising the pop-up heads, and allowing water to be emitted.  
         [0009]     The maximum stress is experienced when the pressure surge is transmitted to the full sprinkler body. That is, the pressure directed through the sprinkler body is not free to simply pass through as the standing water in the sprinkler body must be energized to overcome its static state. This creates the highest stress on the sprinkler body. The location of the maximum stress when such a pressure surge is transmitted is the stress concentrators of the sprinkler body. More specifically, the highest stress concentrator is the knit line bisecting the side inlet and the cylindrical wall.  
         [0010]     One method for examining the strength and durability of a sprinkler body is by repeatedly recreating these conditions. Known as cycle-surge durability testing, a plugged, water-filled sprinkler body is subjected to a series of repeated high-pressure surges at levels often in excess of conditions typically used by a consumer. This allows for recognizing long-term performance deficiencies. In performing such tests, it has been found that sprinkler bodies with a side inlet underperform bodies without a side inlet. More particularly, the side-inlet sprinkler body often fails by rupturing proximate the side inlet and along the knit line.  
         [0011]     Accordingly, it is desired for a side-inlet sprinkler body having improved performance and structural integrity. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a perspective view of a sprinkler having a side-inlet sprinkler body embodying features of the present invention;  
         [0013]      FIG. 2  is a side elevation view of the sprinkler body of  FIG. 1 ;  
         [0014]      FIG. 3  is a fragmentary partial cross-sectional view of the sprinkler body of  FIG. 1 ;  
         [0015]      FIG. 4  is a cross-sectional view of the sprinkler body of  FIG. 1 ;  
         [0016]      FIG. 5  is a cross-sectional view of the sprinkler body of  FIG. 2  generally along line  5 - 5  of  FIG. 2 ;  
         [0017]      FIG. 6  is an environmental schematic of an exemplary irrigation system including the sprinkler body of  FIG. 1  and a first form of a connection to the side inlet; and  
         [0018]      FIG. 7  is an environmental schematic of an exemplary irrigation system including the sprinkler body of  FIG. 1  and a second form of a connection to the side inlet. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]     Referring initially to  FIGS. 1-5 , a sprinkler body  10  is illustrated having a generally tubular wall  11  with an internal surface  9 , a side inlet  12 , a bottom inlet  14 , and a riser opening  16 . The riser opening  16  of the sprinkler body  10  receives a riser  32  (see  FIGS. 1 and 6 ), and the riser  32  may move between an extended position ( FIG. 6 ) and a retracted position ( FIG. 7 ). More specifically, the application of water pressure into the sprinkler body  10  forces the riser  32  to move from a generally retracted position, substantially within the sprinkler body  10 , to a position extended from and above the sprinkler body  10  for emitting water to a surrounding area. When water is shut off, the riser  32  retracts from the extended position, preferably biased towards the retracted position by a spring  17 .  
         [0020]     The length of the sprinkler body  10  is dependent on the length of the riser  32 , which is in turn dependent on the application for the sprinkler and the surrounding environment. For shorter risers  32 , the sprinkler body  10  is similarly short. Conversely, longer risers  32  require a longer sprinkler body  10 . When installed with a sprinkler system, the sprinkler body  10  is sunk into the ground and is connected to the water source through piping that is also sunk, as can be seen in  FIGS. 6 and 7 . In the event the water source piping is connected to the bottom inlet  14  inlet, at least a portion of the water source piping must also be sunk in the ground to that depth. In order to minimize the depth to which the water source piping must be sunk, the sprinkler body  10  is provided with the side inlet  12  for connection to the water source piping.  
         [0021]     During installation, the inlets  12 ,  14  are either selectively connected to the water source or capped. That is, the side inlet  12  may be connected to the water source when the bottom inlet  14  is capped, or the side inlet  12  may be capped as the bottom inlet  14  receives water from the water source. The internal pressure surge and fluctuation from activating or de-activating the water pressure causes stress at the side inlet  12 , regardless of whether the side inlet  12  is capped or not.  
         [0022]     The water source may deliver water to the sprinkler body  10  through either inlet  12 ,  14  into an elongate cavity  13  defined by the internal surface  9  of the sprinkler body  10 . The side inlet  12  defines a passage  20  for permitting water received from the water source to enter the sprinkler body  10  and includes a cylindrical wall  34  for connecting to a delivery system  100  (see  FIGS. 6, 7 ).  
         [0023]     The sprinkler body  10  may be provided with reinforcement structure in the form of one or more reinforcement members. In one form, the internal surface  9  of the sprinkler body  10  includes a plurality of reinforcement members in the form of longitudinally oriented ribs  48  radially located at circumferentially spaced intervals. These ribs  48  cooperate with a riser ratchet  47 , which is a portion of the riser  32 , such that the riser  32  can freely move up and down within the sprinkler body  10 , but may not rotate within and relative to the sprinkler body  10 .  
         [0024]     As mentioned above, the side inlet  12  allows water from the water source to enter the sprinkler body  10 . More specifically, the cylindrical wall  34  is generally orthogonal to the longitudinal axis X of the sprinkler body  10  and surrounds and defines an inlet plate  18  including the inlet passage  20 . The inlet plate  18  may be flat, may follow the general contour of the tubular wall  11 , or may be located above or below the contour of the tubular wall  11 .  
         [0025]     The inlet passage  20  includes a pair of preferably semicircular ports  22  defined by the plate  18  such that ports  22  are separated by a reinforcement member in the form of a brace or crosspiece  38  and surrounded by a reinforcement member in the form of an annular collar  54 . It should be noted that the inlet passage  20  may include an alternatively numbered and shaped ports, though it is preferable that the ports  22  are surrounded by the collar  54  such that the ports  22  are separated a distance from the cylindrical wall  34 , as will be discussed below. It is also preferred that the ports  22  are shaped to minimize sharp angles that would lead to stress concentrations. The preferred crosspiece  38  has an orientation parallel to the central longitudinal axis X of the sprinkler body  10 , and one of the reinforcement ribs  48  preferably comprises or joins with the crosspiece  38  to bisect and support the side inlet  12 .  
         [0026]     The sprinkler body  10  may be formed by an injection molding process. As a result, the sprinkler body  10  often includes an area of non-uniform mechanical properties, or weakening feature, such as a knit or mold line  60 . As illustrated in  FIGS. 1 and 2 , the knit line  60  is located on the tubular wall  11  and generally extends the entire length of the body  10 , though it may extend only a portion thereof. As the knit line  60  is formed by two leading edges of molten plastic flows that are intended to have identical flow rates, the knit line  60  is generally straight though slightly irregular, a fact that is exaggerated for illustrative purposes in the accompanying figures. The knit line  60  is positioned such that it generally bisects the side inlet  12  such that a weak point of the sprinkler body  10  is along the knit line  60  and proximate the side inlet  12 . That is, though slightly irregular and not necessarily straight, the knit line  60  is generally parallel to the central longitudinal axis X and crosses the side inlet  12 . More specifically, the knit line  60  is generally aligned with the center of the side inlet  12 , and the crosspiece  38  is positioned through the center of the side inlet  12  such that the crosspiece  38  and knit line  60  are generally aligned with each other and with the longitudinal axis X. It should be noted that, when the crosspiece  38  is aligned with the knit line  60  in the region of the side inlet  12  and a reinforcement rib  48  is joined with or forms the crosspiece  38 , the entire length of the reinforcement rib  48  may, accordingly, be aligned with the knit line  60 , providing further reinforcement of the sprinkler body  10 .  
         [0027]     As discussed, the ribs  48  cooperate with the riser ratchet  47  for permitting the extension and retraction of the riser  32 . As such, the ribs  48  are sized for being received in the riser ratchet  47 . However, the size of the ribs  48  may not be the same size as that desired for the crosspiece. As can best be viewed in  FIGS. 3 and 5 , the crosspiece  38  may provide further reinforcement by having sides  42  with a greater width than sides  43  of the rib  48   a.  It should be noted that the crosspiece  38  may, alternatively, be smaller than the general width of the rib  48   a,  such as where the ports  22  are dictated to have a large size due to required fluid flow therethrough.  
         [0028]     Again referring to  FIGS. 2 and 3 , the intersection of the crosspiece  38  and the inlet plate  18  is described in more detail. The ports  22  are defined by a semicircular convex or filleted edge  46  of the collar  54  of the inlet plate  18  and a straight convex or filleted edge  44  of the crosspiece  38 . The crosspiece  38  intersects with the collar  54  at a first transition portion  39  and a second transition portion  41 . At each transition portion, the crosspiece  38  and the collar  54  form at least one rounded corner  45  and, as depicted, form four corners  45 . That is, the crosspiece  38  intersects with the collar  54  at the first transition portion  39  to form a pair of rounded corner edges  45   a  and  45   b  with each corner  45   a,    45   b  formed at the intersection of the edge  44  of the crosspiece  38  and the edge  46  of collar  54 . Furthermore, rounded corners  45   c  and  45   d  are formed at the intersection of the crosspiece  38  and the collar  54  at the second transition portion  41 . The plate  18  forms a mass or surface area  47  of the crosspiece  38  and the collar  54 , thereby increasing the material present while still facilitating water passage through the ports  22 . Because the inlet plate  18  with the surface area  47  generally is aligned with the knit line  60 , the inlet plate  18  reinforces the sprinkler body  10  in the region of the knit line  60 .  
         [0029]     As described, the reinforcement members strengthen the sprinkler body  10  along an area of maximum potential stress, specifically at the knit line  60  and proximate to the side inlet  12 . In the prior art, the injected plastic flowed first through the mold to form the tubular wall  11  and then flowed to the mold portion defining the cylindrical wall  34  of the side inlet  12 . In this manner, the knit line  60  would be generally a line along the side of the sprinkler body  10  and, slightly distorted or widened, along the side of the cylindrical wall  34  of the side inlet  12 . With the addition of the crosspiece  38 , the flow of the injected plastic does not have such precise boundaries. Prior-art sprinkler bodies typically include internal ribs, but such prior-art internal ribs do not intersect the area of maximum potential stress.  
         [0030]     More specifically, as the injected plastic forms the crosspiece  38 , the weakness of the knit line  60  is reduced in the region proximate to the cylindrical wall  34 . In one manner, the crosspiece  38  serves to join, without a knit line, both sides of the knit line  60  in the tubular wall  11  proximate to the cylindrical wall  34 . The reinforcing rib  48   a  aligned with the crosspiece  38  also serves to join both sides of the knit line  60 . To the degree that a knit line may form along the length of the reinforcing rib  48   a,  the amount of material along the knit line is increased by the combination of the reinforcing rib  48   a  and the sprinkler body  10 , making the knit line  60  itself stronger. The collar  54  also joins the entire periphery of the side inlet  12  without a knit line. The sprinkler body  10  may incorporate any combinations of these features to provide additional strength along the knit line  60  or to join the tubular wall  11  from both sides of the knit line  60 , thereby providing greater strength and durability when subjected to pressure surges.  
         [0031]     A Rain Bird® Model 1812 sprinkler body having a 12″ length was cycle-surge durability tested. In the table below, “Control” represents a standard, unmodified 1812 sprinkler body, “Reinforced I” represents the sprinkler body modified by rotating the ribs as described above so that a reinforcing rib  48   a  intersected the side inlet  12 , and “Reinforced II” represents the sprinkler body modified by adding the collar  54  and providing the crosspiece  38  with a wider dimension than the reinforcing rib  48   a.  The tests results are an average of cycles-to-failure when the sprinkler body filled with water is subjected to 0-200 psi every 5 seconds, and all failures occurred proximate to the side inlet. The following results were obtained:  
                                                                         Control   Reinforced I   Reinforced II                                    Avg. Cycles to Failure   1878   2224   2467       % Different from Control   —   +18%   +31%                  
 
         [0032]      FIGS. 6 and 7  illustrate the sprinkler body  10  connected to exemplary irrigation systems, which may include a plurality of sprinkler bodies  10  (only one is shown). In a typical irrigation system  100 , the sprinkler body  10  is connected to a lateral pipe  122 , which provides pressurized water to the sprinkler body  10 . The sprinkler body  10 , for instance, may be coupled to the lateral pipe  122  through a spoke pipe  123 , which may include one or more swing joints  124  and one or more sections of coupling pipe  126 . Generally, the spoke pipe  122  and coupling pipe  126  are PVC piping or other suitable tubing and the swing joints  124  include appropriate combinations of PVC nipples, tees, or elbow joints suitable for mating the coupling pipe  126  to the spoke pipe  123 . However, other tubing and connection methods are suitable so long as a water-tight seal is maintained. In this arrangement, irrigation system  100  provides water to sprinkler body  10  through the spoke pipe  123  and also provides water to the other sprinkler bodies  10  (not shown) through the continued and uninterrupted flow of water in the lateral pipe  122 .  
         [0033]     In use, the sprinkler body  10  is coupled with the pop-up riser  32  with a spray head  28   b,  and has a surface flange  24  positioned flush or even with the ground level. The sprinkler body  10  can be used with a variety of spray heads, which the spray head  28   b  is an example. Alternatively, as shown in  FIG. 1 , another type of spray head  28   a  is illustrated. As previously discussed, the riser  32  telescopically translates through the riser opening  16  into the cavity  13  of the sprinkler body  10 . When water is provided to the irrigation system  100 , water flows through the spoke pipe  122  and the bypass pipe  123  and into the sprinkler body  10 . At this point, the water pressure causes the riser  32  to extend a predetermined distance out of the sprinkler body  10 , as shown in  FIG. 6 , to provide water to the surrounding area. When watering is complete and the irrigation water is shut off, the riser  32  retracts or slides back into sprinkler body  10 , as shown in  FIG. 7 .  
         [0034]      FIG. 7  illustrates the sprinkler body  10  within a second exemplary irrigation system  110  using an alternative coupling method and spoke pipe  125 . In this alternative connection, a swing pipe or flexible pipe  128  is coupled to sprinkler body  10  using joints  134 . In this connection method, the joints  134  are generally male NPT pipe couplers and barb elbow joints, though any suitable method that secures or couples the swing pipe  128  to the sprinkler body  10  is suitable. As discussed above,  FIG. 7  shows the sprinkler body  10  with the spray head  28   b  and the riser  32  in the retracted or withdrawn position such that the riser  32  is telescopically received into the cavity  13  of the sprinkler body  10  and a top surface  29  of the spray head  28   b  is flush with the flange  24 .  
         [0035]     It will be understood that various changes in the details, materials, and arrangements of parts and components which have been herein described and illustrated in order to explain the nature of the invention may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.