Patent Publication Number: US-9403177-B2

Title: Sprinkler with multi-functional, side-load nozzle

Description:
This invention relates to sprinklers especially suited for, but not limited to agricultural sprinklers used on center-pivot irrigation machines. 
     BACKGROUND 
     Center-pivot irrigation machines include large truss spans supported on wheeled towers that rotate about a center support. The truss spans mount many sprinklers along the length of the spans, either directly or suspended from the trusses on rigid or flexible drop hoses. 
     Because sprinklers of this type (and particularly the sprinkler nozzles) are oftentimes exposed to unfiltered or poorly filtered water containing sand, dirt, debris, etc., it is necessary to periodically clean or flush the individual sprinklers including the sprinkler nozzle bores. At the same time, it is necessary to install nozzles of different orifice size along the truss span length to obtain the desired flow rate in light of the different circle diameters traced by the individual sprinklers as the machine rotates about its center support. Flushing and/or changing nozzle size generally requires at least some disassembly of the sprinkler (and possibly shutting down the machine), which, multiplied over tens or even hundreds of sprinklers, is labor intensive, time consuming and therefore costly. 
     The present invention seeks to simplify the nozzle changeover and/or flush operations by providing a multi-functional, side-loading nozzle insert that is (1) easily installed and removed, thereby facilitating nozzle changeover; and (2) when installed, easily rotated between, for example, “INSERTION”, “ON”, “OFF”, “NOZZLE FLUSH” and “LINE FLUSH” operating positions. 
     BRIEF SUMMARY OF THE INVENTION 
     In one exemplary but nonlimiting embodiment, the invention relates to a nozzle insert for side-loading into a complementary recess in a sprinkler body comprising an insert body having an axis of rotation, a nozzle bore extending through the insert body on an axis intersecting the axis of rotation; a flush groove on an outer surface of the insert body and configured to direct water laterally away from the sprinkler body; plural index tabs extending radially from the insert body at circumferentially-spaced locations, adapted to engage respective index notches in the sprinkler body; and a turning knob at a forward end of the insert body. 
     In another version, the invention relates to a sprinkler and side-loading nozzle insert assembly comprising a sprinkler body provided with a flow passage along a sprinkler body axis and a nozzle insert received in a complementary recess formed in the sprinkler body, the nozzle insert having an axis of rotation intersecting the sprinkler body axis and rotatable from an insertion position to plural operating positions; the nozzle insert comprising an insert body formed with a nozzle bore extending through the insert body on an axis intersecting the axis of rotation and alignable with the flow passage in at least two of the plural operating positions; and wherein plural radially-extending and circumferentially-spaced index tabs provided on one of the sprinkler body and the nozzle insert are arranged to engage respective plural index notches on the other of the sprinkler body and the nozzle insert as the insert body is rotated to each of the plural operating positions. 
     In still another version, the invention relates to a sprinkler comprising a sprinkler body having a flow passage and an elongated recess extending transverse to the flow passage; a nozzle insert received in the elongated recess and rotatable about an insert axis perpendicular to the flow passage, the nozzle insert provided with a nozzle bore having an inlet and an outlet orifice, and a flush groove extending substantially parallel to the nozzle bore; the nozzle insert rotatable between at least a nozzle ON position where the nozzle inlet is aligned with and adjacent the flow passage; a nozzle OFF position where said flow passage is sealed relative to said nozzle bore; a nozzle FLUSH position where the nozzle outlet orifice is aligned with and adjacent the flow passage; and a LINE FLUSH position where the flush groove communicates with the flow passage. 
     The invention will now be described in greater detail in connection with the drawings identified below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a sprinkler body and nozzle insert in accordance with a first exemplary but nonlimiting embodiment, showing the nozzle insert removed from the sprinkler body and oriented in an INSERTION position; 
         FIG. 2  is a right side, front perspective view of the nozzle insert shown in  FIG. 1 ; 
         FIG. 3  is a left side, rear perspective view of the nozzle insert shown in  FIG. 2 ; 
         FIG. 4  is a right side, top perspective view of the nozzle insert shown in  FIG. 2 ; 
         FIG. 5  is a right side, bottom perspective view of the nozzle insert shown in  FIG. 2 ; 
         FIG. 6  is an enlarged, partial front elevation view of the sprinkler body with the nozzle insert removed; 
         FIG. 7  is a perspective view similar to  FIG. 1  but with the nozzle insert installed within the sprinkler body in the INSERTION position; 
         FIG. 8  is an enlarged, partial front view of the sprinkler body and nozzle insert as shown in  FIG. 7 ; 
         FIG. 9  is an enlarged, partial rear view of the sprinkler body and nozzle insert shown in  FIG. 5 ; 
         FIG. 10  is a view similar to  FIG. 9  but partially sectioned to remove the struts at the back end of the sprinkler body; 
         FIG. 11  is a front elevation view of the sprinkler body and nozzle insert (with the water deflection plate removed), with the nozzle insert rotated in a clockwise direction from the INSERTION position to the nozzle ON position; 
         FIG. 12  is an enlarged partial rear view of the sprinkler body and nozzle insert as shown in  FIG. 11 ; 
         FIG. 13  is a partial vertical cross section viewed from the front of the sprinkler body and nozzle insert as shown in  FIG. 11 ; 
         FIG. 14  is a partial vertical cross section viewed from the right side of the sprinkler body and nozzle insert as shown in  FIG. 11 ; 
         FIG. 15  is a front elevation view similar to  FIG. 11  but with the nozzle insert rotated 45 degrees in a clockwise direction from the ON position to an intermediate position between the ON position and the OFF position; 
         FIG. 16  is an enlarged, partial rear section view of the sprinkler body and nozzle insert as shown in  FIG. 15 ; 
         FIG. 17  is a front elevation view similar to  FIGS. 11 and 15 , but with the insert rotated 45 degrees in a clockwise direction from the intermediate position shown in  FIG. 15  to the OFF position; 
         FIG. 18  is an enlarged, partial left side, rear perspective view of the sprinkler body and nozzle insert as shown in  FIG. 17 ; 
         FIG. 19  is a partial vertical cross section viewed from the right side of the sprinkler body and nozzle insert as shown in  FIG. 17 ; 
         FIG. 20  is an enlarged, partial rear section view of the sprinkler body and nozzle insert as shown in  FIG. 17 , but with the insert rotated slightly less than or about 45 degrees in a clockwise direction from the OFF position to an intermediate position between the OFF position and the NOZZLE FLUSH position; 
         FIG. 21  is a view similar to  FIG. 20  but with the insert rotated a few degrees further in the clockwise direction; 
         FIG. 22  is an enlarged, partial front view of the sprinkler body and nozzle insert as shown in  FIG. 15  but with the nozzle insert rotated 90 degrees in a clockwise direction from the OFF position to the NOZZLE FLUSH position; 
         FIG. 23  is a partial vertical cross section of the sprinkler body and nozzle insert viewed from the right side as shown in  FIG. 22 ; 
         FIG. 23A  is a view similar to  FIG. 23  but rotated to show another circumferential portion of the sprinkler body seal relative to the nozzle insert in the NOZZLE FLUSH position; 
         FIG. 24  is an enlarged, partial front view of the sprinkler body and nozzle insert as shown in  FIG. 20  but with the nozzle insert rotated 90 degrees in a clockwise direction from the NOZZLE FLUSH position to a LINE FLUSH position; 
         FIG. 25  is a partial vertical cross section of the sprinkler body and nozzle insert viewed from the right side as shown in  FIG. 24 ; 
         FIG. 26  is a partial right, rear perspective view of the sprinkler body and nozzle insert as shown in  FIG. 25 ; 
         FIG. 27  is a side elevation of a seal employed between the sprinkler body and nozzle insert in the first exemplary embodiment; 
         FIG. 28  is a perspective view of the seal shown in  FIG. 27 , but illustrating a shape of the seal when installed; 
         FIG. 29  is a top perspective view of a sprinkler body and seal retainer sleeve employed in the sprinkler body as shown in  FIGS. 1-26 ; and 
         FIG. 30  is a top perspective view of the sprinkler body as shown in  FIG. 27  but with the seal retainer sleeve removed. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates a sprinkler assembly  10  that includes a sprinkler body  12  and a nozzle insert  14  receivable within a sideways-oriented, complementary recess  16  provided in the sprinkler body  12 . The sprinkler body mounts a conventional adapter  18  via a threaded coupling at the upstream end  20  of the sprinkler body  12 . A plurality of support struts  22  are provided at the downstream end  24  of the sprinkler body, the support struts connected to a mounting ring  26  adapted for securing a conventional water deflector or distribution plate  28  formed with grooves  30  that typically cause the plate to rotate when impinged upon by a stream emitted from the sprinkler nozzle. The plate  28  may incorporate an otherwise conventional viscous brake or rotational speed-retarding device  32 . 
     Before describing the nozzle insert  14  and sprinkler body  12  in detail, it is important to note that any references to relative terms such as “upper”, “lower”, “left-side”, “right-side”, “front” and “rear”, relate to the sprinkler body and nozzle insert as oriented in the various figures and are not intended to be in any way limiting, because the sprinkler may assume other orientations in use. Since, however, the sprinkler will generally assume the orientation shown in  FIG. 1  or a reverse (inverted) orientation, it is appropriate to refer to the nozzle insert  14  as a “side-loading” nozzle insert. 
     With continued reference to  FIG. 1 , but also especially to  FIGS. 2-5 , the nozzle insert  14  is formed as a substantially-cylindrical body (or, simply, “insert body”)  34 , preferably injection-molded of hard plastic material such as PVC (or other suitable plastic or metal material). The insert body  34  has a longitudinal center axis A ( FIG. 2 ), also referred to herein as the “insert axis” or insert “axis of rotation” that, when installed in the sprinkler body, is perpendicular to a longitudinal center axis B ( FIGS. 1 and 7 ) of the sprinkler body, also referred to herein as the “sprinkler axis”. 
     The insert body  34  is formed with a nozzle bore which, in the illustrated embodiment, extends transversely of the insert axis or axis of rotation A from an inlet end  38  to an outlet end or nozzle outlet orifice  40 . As best seen in  FIGS. 4 and 13 , the nozzle bore  36  is comprised of a straight relatively larger-diameter portion  42  extending from the inlet end  38 , and an inwardly-tapered portion  44  extending from a location about midway between the inlet end and outlet end, and leading to the smaller-diameter nozzle orifice  40 . Note that, because of the internal nozzle bore shape, the outer nozzle bore wall  49  is radially spaced from the orifice  40  at the outlet end of the nozzle bore as seen, for example, in  FIGS. 1-3, 13, 23 and 23A . 
     As best seen in  FIGS. 2-5 , a “flush groove”  46  extends across a first axially-extending solid peripheral portion  48  of the insert body, substantially parallel to the nozzle bore  36  in the illustrated embodiment. The flush groove  46  is defined by the nozzle bore wall  49 , a first side wall  50  and a second side wall  52  that intersects and is extended by a rearward end wall  54  of the cylindrical insert body  34 . The flush groove  46  communicates with a sprinkler body flow passage when the nozzle insert is rotated to the NOZZLE FLUSH position as described further herein in order to direct any debris in the sprinkler body flow passage laterally away from the sprinkler body, and thus also preventing any such debris from entering the nozzle bore. 
     A second axially-extending, solid peripheral portion  56  ( FIG. 3 ) of the insert body  34  is circumferentially spaced from, and preferably diametrically opposite the first solid peripheral portion  48  and is formed with a round concave surface  58  to reduce seal drag when the insert body is rotated. When the nozzle insert  14  is rotated to the OFF position (see  FIG. 19 ), a seal  154  engages the solid peripheral portion  56  surrounding the concave surface  58  as also described further herein. 
     The insert body  34  is also formed with a forward, disk-like end face or wall  60  that, in the exemplary embodiment, is round in shape, with a diameter larger than the diameter of the remainder of the insert body  34  (including the rearward end wall  54 ). The forward end wall is formed or provided on its outward side with a relatively narrow but easily grasped turning knob  62 , which extends centrally across the end wall  60  and through the insert axis A. As shown, the turning knob  62  is tapered to a rounded point  64  at one end and thus also serves as a pointer device that indicates the rotational position of the nozzle insert  14  as indicated by position indicia, e.g., ON, OFF, NOZZLE FLUSH and FLUSH on the sprinkler body at locations corresponding to the four operation positions of the nozzle insert. (Note that the FLUSH indicator on the sprinkler body is also referred to herein as a LINE FLUSH position to more clearly distinguish it from the NOZZLE FLUSH position). To reinforce this positional aspect of the turning knob  62 , an arrow-like indicator  66  may be formed within or on the knob, oriented to match or align with the pointing direction of the knob. Because the indicator  66  is formed as a slot in the illustrated embodiment, it will accept a standard flat-blade screwdriver for situations where extra turning torque may be required due to impacted sand, etc. A nozzle orifice size reference number  68  (see for example,  FIGS. 1, 2, 7 and 8 ) may also be provided on the knob  62  above the arrow-like indicator  66 , providing the user with a clear indication of the nozzle orifice size. It will be appreciated that the nozzle orifice size number could be placed in any readily visible location on the nozzle insert  14 , but preferably on the outwardly facing surface of the forward end wall  60  or on the knob  62  itself (as shown). The nozzle inserts may also be color-coded by orifice size. In addition, the arrow-like indicator  66  as well as the nozzle orifice size reference number  68  could be provided in the form of separately-applied adhesive labels or the like. 
     It will also be appreciated that because the forward end wall  60  is larger in diameter than the insert body  34 , it will serve to shield the user from water spray that may be directed toward the user when the nozzle insert is rotated between its operating positions, or when the nozzle insert is in the NOZZLE FLUSH or LINE FLUSH positions. 
     It will also be appreciated that other reference markings or indicia may be applied to the front face of the insert body  34 . For example, a sprinkler number corresponding to a sprinkler installation location along a truss span could be applied on one side of the turning knob (or other suitable location) to assist in installing sprinklers with correct nozzle sizes in the desired sequence along a center-pivot truss span or the like. In this regard, sprinklers as described herein may be delivered to the customer slidably mounted on a string or wire in a suggested installation sequence as verified by the location numbers on the sprinklers. To this end, openings in the insert body  34  may be utilized for stringing together a series of nozzle inserts. 
     A stop tab  70  projects radially away from the forward end wall  60 , in radial alignment with the tapered, rounded point  64  on the knob  62 . This stop tab assists in the alignment of the insert  14  relative to the sprinkler body  12  for insertion, and also serves as a stop, preventing rotation of the nozzle insert  14  in one of two rotation directions from the insertion position, and preventing further rotation in the other of the two rotation directions at an opposite end of the rotational range of motion of the nozzle insert as described further herein. 
     As noted above, the insert body  34  has a rearward, disk-like end wall  54  of smaller diameter than the forward end wall  60 , but of substantially the same diameter as the solid, diametrically-opposed peripheral portions  48 ,  56 . A hollow, substantially cylindrical extension  72 , concentric with the insert body  34  and insert axis A, extends away from the rearward end wall  54 . At the distal end  74  of the substantially cylindrical extension  72 , there are four index tabs  76 ,  78 ,  80  and  82  (best seen in  FIGS. 3 and 4 ) extending radially outwardly at 90-degree intervals about the distal end  74  of the substantially cylindrical extension  72 . Each index tab has a rounded U-shape when viewed in plan, including a front face  84 , and a pair of spaced, substantially-parallel and rearwardly-extending stems  86 ,  88 . For convenience, the reference numbers  84 ,  86  and  88  are used with each of the index tabs, noting that the separate numbers for the four index tabs per se facilitate the description of the rotation of the nozzle insert  14  from the INSERTION position through four additional indexed operating positions. Note that all the index tabs have similar width dimensions as defined by front faces  84 , and similar cross-sectional shapes. Two of the index tabs, i.e., diametrically-opposed tabs  76  and  80 , have a different geometry than the remaining two tabs. Specifically, stems  88  and  86  (see  FIG. 2 ), of tabs  76  and have greater radial length dimensions, and these extended stems are substantially radially aligned as best seen in  FIG. 3 . As described further below, the extended stems, in combination with matching insert slots formed in the sprinkler body, ensure foolproof, one-way-only insertion of the nozzle insert  14  into the sprinkler body  12 . 
     By locating the index tabs  76 ,  78 ,  80  and  82  at the distal end  74  of the substantially cylindrical portion  72 , an axial gap  90  (see  FIGS. 4 and 5 ) is established between the index tabs and the rearward end wall  54 . Also note that index tab  76  is aligned with stop tab  70 . 
     Between the forward end wall  60  and the rearward end wall  54  are various structural surfaces/ribs that serve to strengthen the insert body and/or that provide bearing surfaces when the nozzle insert  14  is installed in the recess  16  in the sprinkler body  12 . For example, referring especially to  FIGS. 4 and 5 , at the nozzle bore inlet  38  the nozzle bore wall  49  is strengthened by radially-extending ribs  92 ,  94  that extend along substantially the entire length of the nozzle bore, on either side of a center web  96  extending between the rearward end wall  54  and the similarly-sized disk-like wall  98  located behind and adjacent the forward end wall  60 . Rib  94 , as well as solid peripheral portions  48 ,  56  extend beyond the wall  98  and join to the back side of the forward end wall  60 . Note that the sides  50  and  52  of the flush groove  46  also extend from and reinforce the nozzle bore wall  49  along the length of that wall. The rearward end wall  54  and the similarly sized and shaped wall  98 , along with peripheral portions  48 ,  56  provide bearing surfaces for the insert  14  as it rotates within the sprinkler body  12  as explained further herein. It will be understood that the location and configuration of the various reinforcement ribs are determined at least in part by manufacturing considerations, especially if the insert is of molded plastic construction and, as such, are not intended to limit the scope of the invention. Openings created between the forward end wall  60  and wall  98 , and as further defined by the rib  94  and peripheral wall portions  48 ,  56 , permit stringing together of multiple nozzle inserts as mentioned above. 
     Note that the sides  50  and  52  of the flush groove  46  also extend from and reinforce the nozzle bore wall  49  along the length of that wall. The rearward end wall  54  and the similarly sized and shaped wall  98 , along with peripheral portions  48 ,  56  provide bearing surfaces for the insert  14  as it rotates within the sprinkler body  12  as explained further herein. It will be understood that the location and configuration of the various reinforcement ribs are determined at least in part by manufacturing considerations, especially if the insert is of molded plastic construction and, as such, are not intended to limit the scope of the invention. 
     Returning to  FIG. 1  and with additional reference to  FIGS. 6, 7 and 9 , the sprinkler body recess  16  is defined by a substantially-cylindrical wall  100  concentric with the insert axis or axis of rotation A (see  FIG. 2 ). The recess  16  is open at a forward end  102  as viewed in  FIG. 1  and partially closed at a rearward end  104  by four, equally-spaced, radially-oriented struts  106 ,  108 ,  110  and  112 , joined at a center hub  114  ( FIG. 9 ). An internal radial flange or collar  116  is located adjacent but axially spaced forwardly of the struts  106 ,  108 ,  110  and  112 . The flange  116  is substantially axially-aligned with a distal end of a substantially cylindrical spring support  118  extending forwardly of the center hub  114 . The flange  116  is formed with four radially-oriented insert slots  120 ,  122 ,  124  and  126  that are spaced and oriented to mate with and receive the four index tabs  76 ,  78 ,  80  and  82 , respectively, on the insert body  34 . Note that the shapes of slots  120  and  124  match the shapes of the index tabs  76  and  80 , respectively that have stems with extended radial length dimensions. As noted above, with this arrangement, insertion of the insert body  34  into the sprinkler body recess  16  can only be achieved in one orientation of the insert body, i.e., with tabs  76 ,  80  aligned with insert slots  120  and  124 . This orientation of the nozzle insert  14  relative to the sprinkler body  12  is referred to herein as the INSERTION position. Upon insertion, the axial gap  90  between the index tabs and the rear end wall  54  is able to receive the flange  116 , and the gap between the flange  116  and the struts  106 ,  108 ,  110  and  112  permits the index tabs  76 ,  78 ,  80  and  82  to rotate behind the flange  116 . 
     On the back side of the flange  116  (i.e., the side facing the struts  106 ,  108 ,  110  and  112 ), there are four substantially identical index notches  128 ,  130 ,  132  and  134  ( FIG. 9 ), located circumferentially between the insert slots  120 ,  122 ,  124  and  126  and sized to receive any one of the index tabs  76 ,  78 ,  80  and  82 . As explained in greater detail below, after insertion, the nozzle insert  14  may be rotated from the INSERTION position to any of four additional operating positions, as defined by the locations of the index notches  128 ,  130 ,  132  and  134 . It will be appreciated that in other versions, the index tabs and index notches may be reversed, such that the tabs are located on the flange  116  and the notches are located, for example, on forward faces of radial projections formed on the cylindrical portion  72 . 
     Within the recess  16 , there is a pair of substantially-parallel elongated ribs  136 ,  138  that extend internally along the wall  100 , parallel to axis A. These ribs provide bearing surfaces for the insert body  34  during insertion and subsequent rotation of the nozzle insert  14  between its various operating positions. As will be appreciated, ribs  136 ,  138  also help center or align the insert  14  within the recess  16  in addition to minimizing surface friction during rotation. 
     As noted above, a generally-cylindrical spring support  118  extends forwardly of the center hub  114 . A coil spring  140  is received over the spring support and lies on the insert axis A. The forward end of the spring  140  engages the center portion of the rearward end wall  54 , inside the substantially cylindrical portion  72 , and thus exerts a force on the insert body  34  in a direction opposite the insertion direction. It will be appreciated that various spring-mounting/retaining arrangements as well as other spring types may be employed and remain within the scope of the invention. 
     With reference to  FIGS. 13 and 14 , an inlet end of the sprinkler body  12  is formed with a flow passage  142  including a first aperture  144  concentric with the sprinkler body axis B and that opens in the wall  100  so as to align with the nozzle bore  36  when the nozzle insert  14  is in the ON position. An outlet end of the sprinkler body is formed with an aperture  146  axially aligned with aperture  144  that aligns with the nozzle orifice  40  when the nozzle insert is in the same ON position. 
     The sprinkler body  12  is also formed with nozzle bore access apertures or openings  148 ,  150  (see e.g.,  FIGS. 1, 13, 18, 26 ), preferably on diametrically-opposed sides of the wall  100 , transverse to both the insert axis A and the sprinkler axis B as described further below. When the nozzle insert  14  is in either the OFF position or the LINE FLUSH position, the nozzle bore  36  is aligned with the openings  148 ,  150  providing ready access to the nozzle bore for manual cleaning in the event debris is tightly wedged in the nozzle bore and not able to be flushed out in the NOZZLE FLUSH position. 
     A seal retainer sleeve  152  is mounted in the flow passage  142  and cooperates with the edge of the aperture  144  to mount a relatively soft, rounded seal  154  engageable with the contoured edge of the bore wall  49  at the inlet end  38  of the nozzle bore  36  as described further herein (see  FIGS. 13, 14 ).  FIGS. 27 and 28  illustrate the seal  154  in isolation.  FIG. 27  shows a side elevation of the seal  154  in a normal uninstalled state, where the otherwise flexible seal assumes a substantially planar orientation. The seal  154  may be characterized as a “double o-ring” seal including joined inner and outer ring portions  156 ,  158 , which enable secure attachment about the outer ring  158 , while allowing flexing of the inner ring portion  156  to conform to the surface of the insert body  34 , i.e., the surface surrounding the nozzle bore  36  at the inlet end  38 .  FIG. 28  illustrates the shape assumed by the seal when installed, conforming to the cylindrical shape of the insert body  34 . In addition, the “double O-ring” configuration is particularly advantageous in that, as the nozzle insert body  34  rotates across the seal, the inner ring portion  156  conforms to the surface of the nozzle insert body, while the rounded shape of the inner ring portion reduces the likelihood of excessive friction that might otherwise lead to tears or other undesirable surface abrasion. At the same time, the relatively soft, flexible material provides an effective seal with only a light compression force. Traditional ball and plug valves use hard seals with high compression loads required to effect the seal, resulting in a further need for a relatively large and otherwise undesirable handle to overcome the friction. 
       FIG. 29  shows the seal retainer sleeve  152  mounted within the flow passage  142  in the sprinkler body. The seal retainer sleeve  152  supports the seal  154  about its outer peripheral edge  158  (see  FIGS. 13, 14, 19, 23 and 25 ), and effectively clamps the seal  154  between the lower edge of the seal retainer sleeve  152  and a radial flange  160  surrounding and defining the aperture  144 . Note that the lower end of the seal retainer sleeve is also shaped to conform to the inlet end  38  of the nozzle bore  36 . As noted above, this arrangement allows the inner portion  156  of the seal to flex as needed to conform to the curvature of the insert body  34 .  FIG. 30  shows the interior of the sprinkler body  12  and especially the flow passage  142 , including a flat  162  that mates with a corresponding flat  164  on the retainer sleeve  152 , facilitating proper alignment and installation of the seal retainer sleeve within the flow passage  142 . Note that the retainer sleeve  152  is held in place by the adapter  18 , and that an additional annular seal  166  (e.g., an o-ring seal) may be inserted in a groove  168  in the seal retainer sleeve thereby preventing leakage at the sleeve/adapter interface. 
     A tab  170  extends axially from the forward edge of wall  100  and cooperates with the stop tab  70  to initially assist in alignment of the nozzle insert  14  with the sprinkler body  12  in the INSERTION position, and to then also limit rotation of the insert  14  to rotation in a clockwise direction from the INSERTION position through the four indexable operating positions. In other words, at the fourth position (the LINE FLUSH position), the nozzle insert  14  can be rotated no further in the clockwise direction, and must be rotated in a counterclockwise direction to return to any one of the other three operating positions and/or to return to the INSERTION position if it is desired to remove the nozzle insert  14  from the sprinkler body  12 . 
     The sprinkler body is also provided with aligned apertures  174 ,  176  which align with the flush groove  46  when the nozzle insert is rotated to the LINE FLUSH position. 
     Operation 
       FIG. 1  illustrates the orientation of the nozzle insert  14  relative to the sprinkler body  12  required for insertion (i.e., in the INSERTION position). When the insert body  34  is properly aligned, with tab  70  engaging lower edge  172  of the stop  170  ( FIGS. 7 and 8 ) the index tab  76  is automatically aligned with the insert slot  120  ( FIGS. 9 and 10 ), permitting insertion of the nozzle insert into the sprinkler body  12 , with all the index tabs passing through respective insert slots in the radial flange  116 . The nozzle insert  14  is shown fully inserted into the complementary recess  16  in the sprinkler body  12  in  FIGS. 7-10 . Specifically, and as best seen in  FIG. 10 , the extended-length index tabs  76  and  80  have passed through the matching insert slots  120  and  124 , while index tabs  78 ,  82  have passed through the remaining insert slots  122 ,  126  ( FIG. 10 ). It will be understood that the spring  140  provides some resistance to the insertion, but the resistive force is necessary to insure good engagement of the index tabs in respective ones of the index notches  128 ,  130 ,  132  and  134  on the backside of the flange  116  as described further below. Once the insert is rotated slightly in the clockwise direction, and as the index tabs engage the backside of the radial flange  116 , the insert  14  is retained within the recess  16  so that it will not be pushed out of the recess until and unless the insert is returned to the INSERTION position. 
     Note that the sprinkler body  12  is provided with indicia on its forward wall  60  and/or on the wall  100  that indicate the various operating positions of the nozzle insert  14 . As best seen in  FIGS. 1, 7 and 18  the operating positions are indicated by the indicia PUSH &amp; TURN (for the INSERTION position), ON, OFF ( FIG. 18 ), NOZZLE FLUSH and FLUSH (for the LINE FLUSH position). 
       FIGS. 11-14  show the nozzle insert  14  rotated 45 degrees in the clockwise direction from the INSERTION position to the ON position. In the ON position, the nozzle bore  36  is axially-aligned with the apertures  144 ,  146  in the sprinkler body, with leakage prevented by the seal  154  at the inlet end  38  of the nozzle bore  36 . As noted above, the inner ring  156  of the seal will engage and conform to the contour of the bore wall  49  at the inlet  38  to the nozzle bore  36 , recognizing that the wall  100  is also cylindrical, and that the inner ring  156  of the seal conforms to the shape of the wall  100  and to the insert body  34  at the bore wall  49  ( FIG. 13 ). At the outlet orifice  40 , no seal is necessary because the nozzle orifice is of a lesser diameter than the sprinkler body outlet aperture  146  ( FIG. 14 ), providing ample space for a stream emitted from the orifice  40  to pass through the aperture  146  and subsequently impinge on the deflector plate  28 . In addition, note that the spring  140  continues to exert a force in a direction opposite the INSERTION direction and, in the ON position, the spring urges the index tabs  76 ,  78 ,  80  and  82  into the corresponding index notches on the rear face of the flange  116 . Specifically, index tab  76  is seated in index notch  128 ; index tab  78  is seated in index notch  134 ; index tab  80  is seated in index notch  132  and index tab  82  is seated in index notch  130  (see  FIG. 12 ). Note that because the index tabs  76  and  80  are radially longer than the remaining index tabs  78  and  82 , the nozzle insert will be retained within the sprinkler body recess as it rotates between its various operation positions. In addition, as the nozzle insert  14  rotates between operational positions, the rotation movement itself is facilitated by the beveled or angled edges of the index tab stems that interact with the edges of the index notches. The dimensions of the tabs and notches are such that the beveled edges engage the notch edges, preventing full seating of the tabs within the notches and facilitating rotation out of the operating positions even with the spring urging the index tabs toward the index notches. 
       FIGS. 15 and 16  illustrate the nozzle insert rotated about 45 degrees in a clockwise direction beyond the ON position to an intermediate position between the ON position and an OFF position. Here, the index tabs have rotated out of their respective index notches and are passing over the insert slots, moving counterclockwise as viewed in  FIG. 16 . Note that the extended stems on the index tabs engage the back side of the flange  116  and thus counter the force of the spring  140  even when the shorter stems align with respective insert slots. This arrangement also prevents escape of the nozzle insert  14  from the recess  16 . 
       FIGS. 17-19  illustrate the nozzle insert  14  rotated about 45 degrees further in the clockwise direction to the OFF position. In this position, and as best seen in  FIG. 19 , surface  56  and the concave surface  58  shut off flow through the sprinkler body flow passage  142 , and surface  56  is sealed by the seal  154  to prevent leakage. In this position, the index tabs  76 ,  78 ,  80  and  82  are seated, respectively in index notches  134 ,  132 ,  130  and  128  ( FIG. 18 ). In addition, the nozzle bore  36  is now aligned with the openings  148 ,  150  in the sprinkler body thus permitting the nozzle bore to be cleaned manually of any debris that is tightly wedged in the bore  36  and unable to be removed when the nozzle insert is rotated to the NOZZLE FLUSH position. 
       FIG. 20  is an enlarged, partial rear section view of the sprinkler body and nozzle insert, but with the insert rotated slightly less than or about 45 degrees in a clockwise direction (as viewed from the front) from the OFF position to an intermediate position between the OFF position and the NOZZLE FLUSH position. It can be seen that the index tabs have rotated out of their respective index notches as shown in  FIG. 18 , and here again, the mismatched index tabs ride across the back side of the flange  116 ; and because of the mismatch with the insert slots, the nozzle insert is not pushed forward by the spring  140  when the index tabs are circumferentially between the index notches on the back side of flange  116 . 
       FIG. 21  is a view similar to  FIG. 20  but with the insert rotated a few degrees further in the clockwise direction (counterclockwise as viewed in  FIG. 21 ). Note that the index tabs  76 ,  80  with lengthened stems do not match the extended insert slots  124 ,  120 , respectively, as the nozzle insert rotates away from the position shown in  FIG. 20 . Thus, the index tabs can move through the insert slots in only one position, i.e., the INSERTION position shown in  FIG. 9 . 
       FIGS. 22-23A  show the nozzle insert rotated 90 degrees in a clockwise direction from the OFF position shown in  FIG. 17  to the NOZZLE FLUSH position. Here, the nozzle bore  36  is inverted relative to its orientation in the ON position; and while not shown, it will be understood that the index tabs  76 ,  78 ,  80  and  82  are now respectively seated in index notches  132 ,  130 ,  128  and  134 . With the nozzle bore  36  inverted, flushing of the bore is facilitated by the expanding diameter of the bore in the direction of flow, i.e., from the smaller-diameter orifice  40  toward the larger-diameter inlet end  38 . In the NOZZLE FLUSH position, there is a significant gap  161  between the seal  154  and the nozzle bore wall  49 , varying about the periphery of the seal/bore wall interface (compare  FIGS. 23 and 23A ). Leakage from the nozzle orifice  40  across the bore wall  49  through the gap  161  provides a visual indicator to the user, even from long distances, that the nozzle is not in the ON position. This is important because with some nozzle sizes, the user may inadvertently leave the nozzle in the NOZZLE FLUSH position thereby producing a misdirected flow and an incorrect flow rate which, if not quickly identified, can lead to crop damage. 
       FIGS. 24-26  show the nozzle insert  14  rotated an additional 90 degrees in a clockwise direction from the NOZZLE FLUSH position to the LINE FLUSH position. Here, water from the sprinkler body flow passage  142  is introduced directly into the flush groove  46  and the water exits the aligned apertures  174 ,  176  ( FIGS. 1, 7 ) on either side of the sprinkler body, thereby flushing the flow passage  142 . Note also that in the LINE FLUSH position, the nozzle bore  36  is again aligned with the apertures or openings  148 ,  150  in the sprinkler body, enabling manual access and cleaning of the bore as described above. 
     In the LINE FLUSH position, the nozzle insert cannot be rotated further in the clockwise direction because the tab  70  is engaged with the stop tab  170 . The nozzle insert  14  can, however, be rotated in a counterclockwise direction to any one of the NOZZLE FLUSH, OFF, ON or INSERTION positions. Rotation back to the INSERTION position allows easy removal (with the assistance of the spring  140 ) and replacement of the nozzle insert with one having, for example, a larger or smaller nozzle orifice size. 
     An important feature of the illustrated embodiment is the manner in which the variously-described structural features combine to accurately align the nozzle insert  14  in the ON position. More specifically, the centerline of the nozzle bore  36  must be positioned within ±0.005″ of the sprinkler body flow passage centerline in the left to right and fore to aft directions, and must be positioned rotationally about axis A within ±0.5°. The combination of water pressure and seal compression forces the insert  14  (and hence the insert body  34 ) against ribs  136  and  138  and thereby accomplishes the left-to-right centering. The tab/detent/spring arrangement accomplishes the fore-to-aft and the rotational centering. There is also a very fine balance that has to be maintained with respect to stability and ease of use. For example, the nozzle insert needs to be securely positioned such that when jostled by crops such as corn stalks, it won&#39;t be inadvertently moved out of the desired operating position. At the same time, however, the nozzle insert must be relatively easy to insert and rotate by hand (perhaps hundreds of times in a day when doing initial assembly of pivot packages or changing out systems in the field). In addition, it is important for the user/operator to know with certainty that the nozzle is properly positioned. This is accomplished by enabling the user to feel or hear the index tabs snap or click into the index notches by reason of the axial force exerted by the spring  140 . When changing operating positions, the user can push and turn (easier option) or just turn (more torque required) the nozzle insert  14  until rotation begins. Then, if the user continues turning without pushing, the nozzle insert body will click into the next set of index notches. This rotation and spring action will accurately locate the nozzle insert so long as the nozzle insert is sufficiently free to move axially and rotationally and thereby enable the spring  140  to drive the index tabs fully home (i.e., where the beveled index tab surfaces are in full contact with the beveled index notch surfaces). 
     To insure the required freedom of movement of the nozzle insert, generous clearances are maintained between the nozzle insert and the sprinkler body wherever possible (such clearances cause the water spray mentioned above that is shielded by the forward end wall  60 ). Further in this regard, the nozzle insert itself is formed to permit water to leak past the seal  154  during position changes to flush out impacted sand, etc. 
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements.