Irrigation emitter
This is a continuation, of application Ser. No. 529,712, filed Dec. 5, 1974, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention is related to my previous U.S. Pat. No. 3,767,124 and like the preceding patent accomplishes self-flushing when the water supply is first turned on, and during final flow when the water is shut-off. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an irrigation emitter which is summarized in the following objects: 
     First, to provide an irrigation emitter wherein a fixed passage wall element having a central restricted flow groove confronts a flexible passage wall element contacting the fixed element along its side margins to form with the fixed element, a flush passage, when subjected to minimal pressure at the start and finish of a flow cycle and to form a restricted passage confined to the groove when subjected to increased pressure during a flow cycle. 
     Second, to provide an irrigation emitter, an embodiment of which is arranged for connection to a flow line through a lateral port and includes a yieldable retainer clip to secure the emitter in essentially parallel contiguous relation with the flow line, this embodiment having a single flush passage and corresponding restricted flow passage or a pair of coaxial oppositely directed passages. 
     Third, to provide an irrigation emitter wherein other embodiments include a set of fixed and flexible passage forming elements arranged in a circle. 
     Fourth, to provide an irrigation emitter as indicated in the previous object which with minimum change in parts may be arranged for drip flow, trickle flow, mist spray or sprinkler spray during an irrigation flow cycle and, in each case, undergoes flush flow at the start and finish of a flow cycle. 
     Fifth, to provide an irrigation emitter, as indicated in the preceding object, wherein when arranged for mist or sprinkler spray discharge may also be arranged to produce spray patterns arranging from a segmental spray to a full circle spray. 
     Sixth, to provide an irrigation emitter which utilizes a novely arranged irrigation line and a ring of removably attached distributor tubes. 
    
    
     DESCRIPTION OF THE FIGURES 
     FIG. 1 is an end view of one embodiment of the irrigation emitter having a single emitter outlet. 
     FIG. 2 is a side view thereof shown in position on an irrigation line. 
     FIG. 3 is an enlarged longitudinal sectional view thereof taken through 3--3 of FIG. 1. 
     FIG. 4 is a transverse sectional view thereof taken through 4--4 of FIG. 3 showing the emitter in its flush condition. 
     FIG. 5 is a sectional view corresponding to FIG. 4 showing the emitter in drip condition. 
     FIG. 6 is a further enlarged sectional view taken through circle 6 of FIG. 5 showing the drip passage. 
     FIG. 7 is a side view corresponding to FIG. 2 showing a further embodiment wherein the emitter has two oppositely directed outlets. 
     FIG. 8 is an end view taken through 8--8 of FIG. 9 showing partly in section, a further embodiment of the irrigation emitter wherein a plurality of emitter outlets are arranged in a circle. 
     FIG. 9 is a side view thereof. 
     FIGS. 10 and 11 are enlarged fragmentary sectional views thereof taken respectively through 10--10 and 11--11 of FIG. 8. 
     FIG. 12 is a fragmentary sectional view taken through 12--12 of FIG. 10. 
     FIG. 13 is an end view of the fixed wall member shown in FIGS. 8, 10, 11 and 12. 
     FIG. 14 is an end view of the flexible wall member shown in FIGS. 8, 10, 11 and 12. 
     FIG. 15 is a reduced fragmentary sectional view corresponding to the region within circle 15 of FIG. 10, showing a manner of connection to a supply line having a set of integral distributor lines. 
     FIG. 16 is a transverse sectional view of a supply line of the type indicated in FIG. 15; that is, having a ring of distributor tubes. 
     FIG. 17 is a similar transverse sectional view of a modified supply line which, when free of pressure, occupies a flat shape. 
     FIG. 18 is a plan view of a further embodiment of the irrigation emitter arranged for mist or sprinkler discharge to produce a segmental spray pattern. 
     FIG. 19 is an enlarged transverse sectional view thereof taken through 19--19 of FIG. 18. 
     FIG. 20 is an enlarged fragmentary transverse sectional view thereof taken through 20--20 of FIG. 18. 
     FIGS. 21, 22, 23 and 24 are transverse sectional views at the same scale as FIG. 18 taken respectively through 21--21, 22--22, 23--23 and 24--24 of FIG. 19. 
     FIG. 25 is a side view partly in section of a further embodiment utilizing most of the elements of the embodiment shown in FIGS. 18 through 24 but which is adapted to produce a drip discharge from a ring of outlets. 
     FIG. 26 is a fragmentary sectional view corresponding to FIG. 19, but at a reduced scale, illustrating an embodiment wherein the fixed wall and flexible wall of the flush passage are curved in the same direction. 
     FIG. 27 is a sectional view thereof taken through 27--27 of FIG. 26. 
    
    
     Referring to FIGS. 1 through 5, the embodiment of the irrigation emitter here illustrated includes a tubular inner shell 1 of essentially rigid plastic material capable of being injection molded. The shell forms a fixed concave passage wall 2 having a centered longitudinally extending drip or minimum flow groove 3. Joined to the side margins of the wall 2 is a confronting concave wall 4, the two walls forming a longitudinally extending cavity which is essentially almond or oval shaped in cross section. Continuing from one end of the inner member is an integral cap 5 having a short laterally extending flanged stem 6, forming an inlet passage 7. 
     Initially slidably fitting the inner shell 1, is an outer shell 8, also molded of essentially rigid plastic material which is cemented or otherwise permanently attached thereto. The end of the shell 8 opposite from the cap 5 is provided with an internal shoulder 9 confronting the end of the inner shell 1 and continues to form a tubular extension 10 forming an outlet passage 11. Extending laterally from the outer shell 8 in the same direction as the stem 6 is a pair of curved arms forming a clip 12. 
     Received in the inner shell 1 is a longitudinally extending concave resilient passage wall 13 formed of rubber or other elastomer and arranged so that its side edges 14 contact the side margins of the passage wall 2 or nearly so. A clearance space is provided between the resilient wall 13 and the confronting wall 4. The resilient passage wall preferably increases in thickness from the cap end of the inner shell toward the tubular extension 9 and terminates in a perforated flange 15 adapted to be clamped between the shoulder 9 and extremity of the inner shell 1. 
     Operation of the embodiment irrigation emitter shown in FIGS. 1 through 6 is as follows: 
     The flanged stem 6 is pressed into a perforation provided in an irrigation tube 16, and the clip 12 is pressed over the tube to secure the emitter in place. When so connected, a passageway is formed through the inlet passage 7, between the fixed and resilient passage walls 2 and 13 and through the outlet passage 11. When water is initially supplied to the irrigation tube; the walls 2 and 13 form a flush passage; however, when the entering pressure rises to between one and three pounds, a differential pressure is created which causes sudden collapse of the resilient wall 13 against the surface of the fixed wall 2 limiting flow to the capacity of the groove 3 as indicated in FIGS. 5 and 6 and by dotted lines in FIG. 3. The size of the groove 3 is predetermined to produce a drip or trickle flow from less than 1 gallon per hour to 3 or more gallons per hour. 
     Also the shape of the groove 3, thickness and hardness of the resilient wall 13 may be preselected so that the rate of flow through the groove may be constant throughout a wide range of pressures; for example, from 5 pounds per square inch or less to more than 60 pounds per square inch, or if desired a preselected rise or fall in flow may be provided. 
     Because the effective length of the drip passage formed by the groove and confronting resilient wall may have substantial axial extent, (in the order of 3/8 to a 1/2 inch or more), accurate control of flow is more readily obtained than if the effective length were substantially less. 
     Also the substantial width of the flush passage formed between the fixed wall and resilient wall (in the order of 3/8 to a 1/2 inch) the collapsing force required is minimal thereby increasing the number of emitters which may be provided for an irrigator line of given size and length; while maintaining flush passages of adequate size to minimize the need to filter the irrigation water. The ability to shift from flush flow to drip flow is also enhanced by the fact that the edges of the resilient wall 13 are in essentially free line contact rather than foldably connected to the walls 3 or to side extensions of the resilient wall 13. 
     In order to minimize entrance of dirt into the outlet passage 11, or to permit placement of the discharge end of the emitter at a desired location, the outlet passage may have an enlarged end to receive a distributor tube 17. 
     Referring to FIG. 7, should it be desired to provide a pair of outlets, a pair of axially aligned inner shells 1 may be joined to a common connector 18 having a lateral stem 6. A pair of outer shells 8 fit over the inner shells and a pair of clips 12 secure the dual emitter to a flow line. 
     Referring to FIGS. 8 through 15. The embodiment here illustrated provides a ring of emitters and includes a housing 19 injection molded of rigid or semi-rigid plastic material and having an annular outer wall 20 and an annular inner wall 21 joined thereto by an annular connecting web 22 having a ring of axially directed outlet passages 23. The inner wall 21 receives an end of an irrigation tube 24 which may be cemented or screwthreaded in place. 
     Fitted between the walls 20 and 21 is an annular fluted member injection molded of rigid or semi-rigid plastic material and forming a ring of integrally connected fixed concave passage walls 25, each having a groove 26 for drip flow. Interposed between the outer wall 20 and fixed passage walls is a ring of inwardly facing concave resilient passage walls 27, formed of rubber or other elastomer, and separated by slits. As described in reference to the first embodiment, the lateral edges 26 of the resilient walls 27a contact or nearly so, the lateral margins of the corresponding fixed walls to form flush passages. The resilient walls 27 are joined at one end by an annular sealing flange 28 which is clamped between the inner end of the fluted member which forms the fixed walls 25. The flange is provided with outlet ports 29 in the form of short tubes extending into the outlet passages 23. 
     The opposite ends of the inner wall 21 and each fixed wall 25 are provided with entrance notches 30 and 31, and alignment notches 32 and 33 interposed circumferentiallly displaced from the notches 30 and 31, which when radially aligned also position the entrance notches in radial alignment. The housing 19 receives a cap member 34 which is permanently cemented or heat sealed or clamped to the outer wall 20. The cap member 34 is provided with radial webs 35 which fit the alignment notches 32 and 33. Each outlet passage 23 receives a distributor tube 36. 
     Each emitter formed by a fixed wall 25 and resilient wall 27 functions in the manner of the fixed wall 2 and resilient wall 13 of the first described embodiment. The embodiment shown in FIGS. 8 through 14 may be mounted at the end of an irrigation line or on a riser. If a double ended cap member is substituted for the cap member 34, a pair of housings 19 may extend in opposite directions in the manner of the dual emitter shown in FIG. 7. In this case, the pair of housings 19 serve to connect sections of an irrigation line in end-to-end relation. Also, if fewer outlets for unit length of the irrigation line is required, the cap member 34 may be provided with an extension sleeve to receive the end of the next section of the irrigation line. 
     In order to simplify installation, particularly when the irrigation line sections are arranged in end-to-end relation, a special irrigation line 37 may be provided as shown in FIGS. 15 and 16. The line 37 is extruded with a ring of distributor tubes 38 integrally attached by severable webs 39. End portions of the tubes are severed as indicated in FIG. 15 for insertion into corresponding outlet passages 23. The inner wall 21 and the outlet passages 23 may have rudimentary grooves to match the component parts of the webs 39 when severed to provide water tight joints which may be cemented. Alternatively, the wall 21 may be slit so as to receive the webs 39 and permit the tubes 38 to remain connected to the line 37. 
     Assuming that each emitter unit is provided with eight emitters and a pair of emitter units are provided at each station in the emitter line. Then if an outlet is needed at each foot, the line between each emitter unit pair would be 16 feet. If the discharge point is intended to be adjacent the irrigation line, then it is merely necessary to cut the distributor tubes at 1 foot intervals. In this case, only 50 percent of the eight 16 foot long distributor tubes is used. This extra length may be utilized if it is desired to place outlet points laterally of the irrigation line; that is, appropriate lengths of distributor tubes may be stripped from the line and their ends placed at appropriate lateral locations. 
     In order to insure sufficient rise in pressure to effect transfer from flush to drip condition, the irrigation line may be extruded in a flat condition as indicated by 40. The initially flat condition of the irrigation line causes the emitter outlets within each housing 19 or pair of housings to progress from flush condition to drip condition in sequence assuming, of course that the capacity of the irrigation line exceeds the flush capacity of the emitters in a single corresponding housing or pair of housings. The concept of a normally collapsed emitter line or section thereof is more fully disclosed in my prior U.S. Pat. No. 3,779,468. pg,13 
     Reference is now directed to FIGS. 18 through 24. The construction here illustrated also provides a ring of outlets, however the drip or minimum flow passages direct the water against deflector surfaces to produce a spray pattern and, in this regard, is a further development of an embodiment shown in the aforementioned U.S. Pat. No. 3,779,468. The present embodiment of the emitter is intended to discharge one or more segmental sprays. For example, the emitter is divided into eight units, each arranged to discharge a spray subtending a 45° angle. By closing selected units, the spray pattern may range from 45° to a full circle in 45° increments. 
     More particularly, this embodiment includes a cylindrical housing 41 injection molded of rigid or semi-rigid plastic material. The housing is closed at one end, except for an inlet fitting 41a, and is provided with a set of longitudinally extending internal ribs 42. Received in the housing 41 is a resilient tubular sleeve 43 formed of rubber or other elastomeric material and having outwardly curving flute elements 44 of arcuate cross section separated by slits and received between the ribs 42. Any one or all of the flute elements serve as the resilient walls of corresponding discharge passages. The flute elements are joined together at their upper ends to form an annular sealing band 45 which overlies the upper end of the housing 41 including a radial portion and an axial portion. Fitted over the band 45 and upper end of the housing 41 is an annular retainer ring 46 having an upwardly and outwardly sloping top surface in the form of an obtuse cone. 
     Received over the retainer ring 46 is a cap 47 having an axially extending shell 48 fitting within the sleeve 43. In the construction illustrated, the emitter is provided with four active units and four inactive units, so as to discharge a half-circle spray pattern. Accordingly, one-half of the shell 48 is provided with four flute elements 49 which are convex to confirm to corresponding flexible flute elements 44, and four flute or fixed walls 50 which are concave; that is, curve in the opposite direction with respect to the corresponding flexible flute elements to form therewith flush passages of almond shape cross section. Each concave flute element 50 is provided with a minimum flow groove 51. 
     The portion of the cap 47 corresponding to the region of the shell 48 having the convex flute elements 49 forms a port circle flange 52 overlying and resting on the ring 46. The remaining portion of the cap 47 is provided with a complementary part circle flange 53 with underlying ribs 54. Between each pair of ribs 54, the underside of the flange 53 slopes upwardly with respect to the upperside of the ring 46 and is provided with a radially outwardly diverging flow directing recesses 55 having radially inner apeces continuing from the corresponding minimum flow grooves 51. The upper surface of the cap 47 may be embossed with triangles 56 to suggest the spray pattern. 
     The bottom of the housing 41 is provided with upwardly converging arms 57 terminating in a screwthreaded collar 58 and the center of the cap 41 is perforated to receive a screw 59 which secures the housing 41, sleeve 43, ring 46 and cap 47 together as a unit. The shell 48 and sleeve 43 terminate short of the bottom end of the housing 41 to provide access to the passageways formed by the concave flute elements 50 and corresponding flexible flute elements 44. 
     Operation of the embodiment shown in FIGS. 18 through 24 is as follows: 
     At the start of the irrigation cycle, upward flush flow occurs through the flush flow passage between the mutually concave walls formed by the flute elements 44 and 50 until a predetermined pressure differential across the flute elements 44 is produced whereupon the flute elements collapse limiting flow to the minimal flow grooves 51. This pressure differential may range between less than 1 pound or a few pounds, depending on the strength of the elastomer. 
     If it is desired to cause a mist discharge, the grooves 51 may be equal to the area provided for higher rates of drip or trickle flow. The water on striking the apex end of each recess 55 is caused to fan outwardly producing a mist spray. If it is desired to use the emitter as a sprayer, the dimensions of the grooves 51 are further increased. 
     Reference is now directed to FIG. 25. The embodiment here shown is intended for use as a drip or trickle emitter; however, the housing 41 and tubular sleeve 43 with its flute elements 44 are used. In place of the retainer ring 46 and cap 47, a cap 58 is provided. The cap includes a shell 48 having only concave flute elements 50. In place of the flange elements 52 and 53, a flange 60 is provided having an underlying profile corresponding to the ring 46. The cap 58 is provided with outlet ports 61 communicating with the flush flow passages and drip flow passages formed by the confronting concave flute elements 44 and 50. The outlet ports include tube receiving sockets 62 to receive a set of distributor tubes 63. 
     The embodiment shown in FIG. 5 is particularly suitable for attachment to the end of a hose for garden watering or to a side fitting provided on an irrigation supply line. If used in an orchard, one unit may be used for each tree to be irrigated. Initially, selected tubes may be closed, then as the tree grows the number of active tubes may be increased. Conveniently, this may be accomplished by tube loops of desired length extending between pairs of outlets, which may be severed as more outlets are needed. 
     It should be noted, that while it is preferred that both the fixed and flexible flutes have approximately the same and opposite curvature; the relative contours may vary substantially or one may be flat providing the desired area of the flush flow passage is maintained. 
     Unless restriction is provided continuously or at intervals in the irrigation supply line as disclosed in the aforementioned U.S. Pat. No. 3,779,468, the number of emitters that can be used in a given line is limited if full flushing is desired. That is, if too many emitters are in flush condition, the water pressure may not reach the one to three pounds required to collapse the emitters to drip flow. 
     The number of emitters may be increased by reducing the cross section of the passage when in flush flow condition. This may be accomplished by providing flexible flute elements 64 which curve toward rather than away from the flute elements 50 as shown in FIGS. 26 and 27. A particle too large to pass through the flush passage will lodge at the entrance end when the emitter is in drip flow; then, if the particle is not too large, when the pressure drops to produce flush flow, the force on the particle, though small may be sufficient to drive the particle through. 
     Having fully described my invention it is to be understood that I am not to be limited to the details herein set forth, but that my invention is of the full scope of the appended claims.