Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3807430 A
Publication typeGrant
Publication dateApr 30, 1974
Filing dateJul 24, 1972
Priority dateJul 24, 1972
Publication numberUS 3807430 A, US 3807430A, US-A-3807430, US3807430 A, US3807430A
InventorsKeller J
Original AssigneeKeller J
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Flushing flow control emitter unit
US 3807430 A
Abstract
A flow control emitter unit allowing maximum discharge at low pressures for clean out purposes, and restricting flow at higher pressures whereby continual low volume flow is maintained. A pressure responsive member is biased to a position where flow is through the member and directly through outlet ports in the housing carrying the pressure responsive member. In response to a predetermined pressure acting on the pressure responsive member it is moved to a position whereby free flow to the outlet ports is cutoff and flow to the outlet ports is through a variable restriction. The flow through the variable restriction is governed by the pressure acting on the pressure responsive member.
Images(2)
Previous page
Next page
Description  (OCR text may contain errors)

United States Patent I 191 1 330mm Keller Apr. 30, 1974 F LUSHING FLOW CONTROL EMI'I'IER Primary Examiner-Henry T. Klinksiek UNIT Assistant Examiner-Robert J. Miller [76] Inventor: Jack Keller, 951 E. 320 North,

Logan, Utah 84321 57 ABSTRACT [22] Filed: July 1972 I A flow control emitter unit allowing maximum dis- [21] Appl. No.: 274,302 charge at low pressures for clean out purposes, and restricting flow at higher pressures whereby continual low volume flow is maintained. A pressure responsive [52] US. Cl 137/504, 137/525, 137/525.3 member is biased to a position Where flow is through [51] Ill. Cl. the member and g y through Outlet ports in the [58] held of Search 137/504 525's; housing carrying the pressure responsive member. In 61/13; 239/5 542 response to a predetermined pressure acting on the pressure responsive member it is moved to a position [56] m cued whereby free flow to the outlet ports is cutoff and flow UNITED STATES PATENTS to the outlet ports is through a variable restriction. 3,714,964 2/1973 Livingston 137/504 x The flow through the variable restriction is governed 2,938,538 5/1960 Allen 137/504 by the pressure acting on the pressure responsive 2,960,109 11/1960 Wils0n.... 137/525 X member 7 3,207,171 9/1965 Kryman...; 137/5253 X i. I 12 Claims, 11 Drawing Figures I 20 c/ I l2 33 sewn/V \\A\\III.\\\\\\\Z e xi l2 A v A 2 2 $1 g s e slewmae PATENTEU "R W SHEET 2 BF 2 xw im l Ti 1 FLUSI-IING FLOW CONTROL EMITTER UNIT,

BRIEF DESCRIPTION OF THE INVENTION 1. Field of the Invention This invention relates to emitter 'units for irrigation uses and is particularly related to such units capable of providing both a flushing action at low input pressures and a discharge control action at higher output pressures.

2. Prior Art It has long been recognized that in irrigation, both surface and subterranean, it is often desirable to provide for continuous slow rate water application, i.e., in the range of we to gallons per hour, each from discharge ports along a small diameter pipeline. In order to achieve such a controlled, low volume, continuous flow uniformly in a system using a number of emitters (or drippers) discharging from a main feed line and to minimize variations in discharge resulting from friction losses, topography, etc., it has been found necessary to maintain a relatively high main line pressure.

Where orifice type emitters have been utilized, it has been necessary to use extremely small discharge openings, which tend to clog during use or even during periods of non-use, particularly when they are buried for subterranean irrigation. To prevent clogging, it has been known to use emitters wherein a relativelyunobstructed flow is permitted at low start up" pressures in the main line and that gradually restrict flow as'the main line pressure increases. U.S. Pat. No. 3,546,884, for example, shows such an emitter. In some such devices, a metering stem may be provided to project into and through a flow control orifice and the mechanical movement of the port and stem relative to one another partially eliminates clogging problems. Emitters, or drippers, of this type are disclosed, for example, in U.S. Pat. No. 3,518,831.

SUMMARY OF THE INVENTION The emitter of the present invention is also the flushing type. However, it provides for an initial high volume flushing flow, exceeding the volume of controlled flow thereafter permitted, at low line pressure and particularly during start up of the system and does not rely on mechanical interaction of a relatively movable stem and orifice although such devices can be incorporated into the emitter of the invention if desired. With the emitter of the present invention initial high volume flow is maintained through relatively large, fully unobstructed ports, until the line pressure has essentially reached a predetermined seating pressure. Thereafter, the flow pattern is changed to be through a control orifice having an opening size varied inversely to the pressure in the main line such that a substantially constant Principal features of the invention include a housing having an inlet passage and at least one outlet port. A deformable member, having a flow passage means therethrough, is positioned between the inlet passages and outlet port. A pressure responsive member, ar-

ranged to be acted on by liquid entering the housing, snaps against the deformable member to inversely change the size of the flow passage means proportionately to changes in input pressure.

Other features of the invention include a non-linearly acting pressure responsive member that allows essentially full flushing flow until the seating pressure is reached. Thereafter, with only slight incremental pressure increases the pressure responsive member is quickly and fully moved to a seated, flow restricting position. Means are provided to maintain the resiliency of the pressure responsive member and to quickly return it to its open flow position when the pressure acting thereon is reduced below the seating pressure.

In one embodiment, the pressure responsive means comprises a Belleville spring diaphragm with a central passage therethrough. In other embodiments, the pressure responsive member comprises a specially constructed diaphragm or a leaf spring having both ends or one end secured.

The deformable member may comprise a single notched O-ring, or other partitions with notches or ports provided therein. The partitions are made sufficiently resilient that when the pressure responsive member is biased against them by pressure they will deform to change the size of the notches or ports and will return to their original configuration when the pressure is removed. v

A retainer ring provides means for preventing the pressure responsive available materials and is economically constructed. The. hardness of the deformable member will determine the rate of restriction of flow through the notches or ports thereof, if the other components remain unchanged, and it is a simple matter to replace a deformable member with one having different characteristics to change the flow characteristics of the emitter.

Additional objects and features of the invention will become apparent from the following detailed description and drawings disclosing what are presently contemplated as being the best modes of the invention.

THE DRAWINGS FIG. 1 is a side elevational view of a portion of an irrigation line incorporating a pair of emitters of the invention;

FIG. 2, an enlarged vertical sectional view, taken on the line 2-2 of FIG. I;

FIG.'3, a typical flow curve for the unit shown in FIGS. 1 and 2;

FIG. 4, a view like FIG. 2 but showing another embodiment of the pressure responsive member used;

FIG. 5, a view of the pressure responsive member as in FIG. 4, but in its relaxed state;

FIG. 6, a view like that of FIG. 2, but showing a different type of pressure responsive member;

FIG. 6a, a fragmentary vertical section, taken on the line 6a--6a of FIG. 6;

FIG. 7, a similar view, showing another arrangement of the emitter, utilizing the pressure responsive member shown in FIG. 6;

FIG. 7a, a fragmentary vertical section, taken on the line 7a7a of FIG. 7;

FIG. 8, a top plan view of a single inlet, multiple outlet emitter of the invention; and

FIG. 8a, a vertical section taken on the line 8a-8a of FIG. 8.

DETAILED DESCRIPTION Referring now to the drawings:

In the illustrated embodiment of FIGS. 1 and 2, the emitter (or dripper) of the invention is shown generally at 10. As shown, the emitter includes a cylindrical housing '11 that is exteriorly threaded at both ends. A cap 12 is adapted to be screwed onto the threads at one end and the other end is adapted to be threaded into an interiorly threaded fitting 13 of a liquid supply pipe 14. The supply pipe is connected in conventional fashion to a source (not shown) of liquid under pressure. When the emitter is used for irrigation purposes the liquid fed through the pipe 14 may be water having the purity of drinking water or relatively dirty water from canals, rivers, etc. Fertilizers, herbicides, pesticides, etc. may also be dissolved in the water for distribution to the crops being irrigated.

Cap 12 has a central, upstanding retainer ring 15 formed therein and a flexible O-ring 16 is adapted to tightly seat in the retainer ring. At least one notch 17 is formed in the edge of the O-ring and a corresponding notch 18 may be formed, if desired, in the edge of retaining ring 15.

A dish-shaped diaphragm 19 of the type commonly known as a Belleville spring has its edge securely held between flat washers 20 and 21 that are clamped between housing 11 and cap 12.

Ports 22 and 23 are provided through cap 12, outside of retainer ring 15, and a port 24 is provided through the center of diaphragm 19.

In operation, liquid from pipe 14 enters housing 11 and acts against diaphragm 19. So long as the pressure in housing 11 is not great enough to flex diaphragm 19, the diaphragm remains in essentially the solid line position of FIG. 2, and flow is through the port 24 and out the ports 22 and 23. However, when the pressure acting on diaphragm 19 is sufficient to flex the diaphragm the central portion thereof snaps almost to the plane of the fixed outer edge to engage the O-ring 16, as shown by the dotted line position of the diaphragm in FIG. 2. With the diaphragm seated on the O-ring there is no direct flow from port 24 in the diaphragm to ports 22 and 23. Instead, the flow is through the port 24 and into the space formed within O-ring 16, through the opening or orifice formed by notch 17 and the portion of diaphragm I9 bridging thereover and then out ports 22 and 23. As the line pressure continues to build up, after flexing the diaphragm against the O-ring, the pressure acts on the diaphragm to push it more tightly against the O-ring, deforming the notch and thereby further restricting flow therethrough in inverse proportion to the pressure acting on the diaphragm.

Retainer ring 15, in addition to holding the Oring 16 in place, also limits the extent of compression of the O- ring by the diaphragm and keeps the center of diaphragm 19 from inverting such that it would not have the natural tendency or resiliency to return to the position shown in solid lines in FIG. 2.

The O-ring is preferably made of a suitable rubber, nylon or resinous material having resilient characteristics, and the hardness of the O-ring will determine the extent of closing of the notch 17 as the diaphragm is pressed thereagainst by pressure in the housing 11.

A notch 17, of the type shown in FIG. 2, forms with the seated diaphragm '19 an orifice that regulates flow from port 24 to ports 22 and 23. The notch is a preferred orifice forming structure since, should the orifice become clogged, it will be immediately cleaned out as soon as the pressure acting on diaphragm 19 is sufficiently reduced and the diaphragm moves away from the O-ring.

Other restricted openings can be provided instead of notch 17, and other partition arrangements between the port 24 and ports 22 and 23 can be used in lieu of O-ring 16. For example, a specially constructed ring partition having a hole or slot therethrough could be used to give the desired control, but the notch is preferred because it is less apt to become and remain clogged.

With the diaphragm spring of FIGS. 1 and 2, it has been found that a typical discharge curve of the emitter of the invention is as shown in FIG. 3. As shown, with the unit tested, the diaphragm is spaced from the O- ring and is in its relaxed position until a pressure of just under 4 pounds per square inch develops on the diaphragm, at which time approximately 7 /2 gallons per hour of water is being discharged from the emitter ports 22 and 23. As the pressure on the diaphragm changes from just under to just over 4 pounds per square inch, the diaphragm seats on the O-ring and the flow through the emitter falls off to about 1.2 gallons per hour. Thereafter, as the pressure on the diaphragm increases from just above 4 pounds per square inch to 30 pounds per square inch, the discharge gradually increases from 1.2 gallons per hour to 3 gallons per hour. This discharge rate is maintained even as the line pressure acting on the diaphragm increases to 60 pounds per square inch. It is apparent that since a constant discharge rate can be maintained over such an extended pressure range, many emitters, FIG. 1, can be used on a supply line and very little, if any, flow rate change will occur due to friction losses, topography changes, etc. of a line having a sufficiently high input head pressure. It is also apparent that the initial high flow rate, i.e., 7 /2 gallons per hour through the large flow openings will wash obstructing particles from the emitter ports and purge the O-ring notch 17 before the regulated control through the notch 17 is initiated.

It is also possible to use a specially constructed, prestressed diaphragm to regulate flow through the emitter. Thus, as shown in FIG. 4, a resilient diaphragm 30 can be used in place of the diaphragm 19 previously disclosed. In this embodiment, a resilient diaphragm, made of rubber or the like, has a central portion 31 with a central port 32 therethrough. A thick edge portion 33 surrounds central portion 31 and is angled outwardly therefrom so that when it is positioned the central portion will be pre-stressed and taut. The diaphragm 30 is secured by rotating edge portion 33 into the plane of portion 31 and clamping it between housing 11 and cap 12, thereby stretching the central portion 31 across a ring 34 formed on cap 12. Ring 34 is concentric with retainer ring 15 and surrounds the ports 22 and 23.

In operation of the embodiment shown in FIG. 4, flow is through port 32 and ports 22 and 23 until sufficient pressure acts on the central portion 31 to force it against retainer ring 15. At this time, flow is through port 32 and notch 17 and then through ports 22 and 23. As pressure acting on diaphragm increases over that necessary to seat the diaphragm on the retainer ring the diaphragm deforms into and restricts flow through notch 17. Thus, the flow through the notch is regulated and the size of the orifice formed by the notch and the diaphragm is governed by the pressure on the diaphragm and is made smaller as the pressure increases and the diaphragm distorts into the notch.

In FIGS. 6, 6a, 7 and 7a, there are shown embodiments of the invention wherein the pressure actuated diaphragm is replaced by a pressure actuated reed or leaf spring.

In the embodiment of FIGS. 6 and 6a, a leaf spring 40 is clamped at one end between the housing 11 and cap 12. The spring 40 is wide enough to fully cover the resilient O-ring l6 and is positioned to be directly in the path of a port 41 through a partition 42 covering the end of housing 11 and clamped between the housing and cap 12.

In operation of the embodiment of FIGS. 6 and 6a, liquid from line 14 enters housing 11 and discharges as a jet through port 41, impinging against the spring 40. While the pressure in housing 11 is sufficiently low the jet will not have sufficient impact force to overcome the inherent resilient positioning of the leaf spring and the incoming water will merely flow around the spring and out the emitter discharge port 43.

Emitter discharge port 43 goes through cap 12 and,

unlike the previously disclosed discharge ports 22 and 23, is within the retaining ring 15 and O-ring 16.

When the pressure in housing 11 has increased to a seating pressure determined by the resiliency characteristics of leaf spring 40 the jet through port 41 has sufficient impact .force to drive the spring against the O-ring as shown in FIG. 6a. The differential pressure of the incoming fluid, acting on the spring and the downstream pressure is then sufficient to hold it seated on the O-ring until the pressure in the housing 11 again drops below the seating pressure.

Controlled flow is permitted through the orifice formed between notch 17 and the spring and as the pressure in housing 11 increases and presses the spring against the O-ring the orifice size will be reduced, thereby maintaining a substantially constant flow through the notch and to discharge port 43, in the manner previously described.

It will be apparent that while the spring 40 is shown angled and as having one end secured, that other bowed or straight spring structures could be used and that both ends of the spring used could be secured, with the spring arranged to bridge the O-ring when little or no impact force is applied and to be moved against the O-ring when the impact force has increased sufficiently.

As shown in FIG. 7, the same concepts involving use of a leaf or reed spring, impact driven against a notched, resilient valve seat can be used in a tubular housing of slimmer profile than the housing 11 heretofore described.

In FIG. 7, the housing, shown generally at 50, includes an inlet through-bore 51 and a parallel blind bore 52. A cap 53 is threaded onto housing and closes the open end of blind bore 52 and one end of through-bore .51. A discharge port 54 extends through the wall of blind bore 52 and an O-ring 55, notched at 56 surrounds port 54 and is held in place by a retainer ring 57.

A leaf spring 58 has one end inserted into a slot 5? provided therefor below bore 52 and the other end is angled away from but adapted to completely overlie the O-ring 55. A port 60 extends through the wall 61 between bores 51 and 52 such that liquid entering bore 51 passes through port 60 to strike the spring 58. As in the previously described embodiment, water entering bore 51 at a pressure below the seating pressure of the spring does not create a jet with sufficient impact to move the spring against O-ring 55. However, when the seating pressure is reached the jet has sufficient impact force to move the spring against the O-ring where it is held by the inlet pressure acting on the spring.

It will be apparent that other blind bores, not shown,

could as well be spaced radially around bore 51 and that pressure responsive, impact receiving springs, inlet bores, outlet bores and notched partitions such as O- ring 55 could be provided each blind bore in the same manner as has been described. One common partitioned housing can be used to form all of the bores and the clustered construction will allow controlled flow in a plurality of directions, from a single liquid feed. 7 It is also possible to use a single pressure responsive member to control flow through a plurality of outlets. As shown for example in FIGS. 8 and 8a, there is provided a tubular housing 70, exteriorly threaded at both ends so that one end can be threaded into a main liquid supply line and such that a cap 71 can be threaded onto the other end. Cap 71 has a plurality of discharge'ports 72 through the end thereof and each port opens into a space between adjacent ones of partitions 73 (four such partitions being shown) that extend from the end of cap 71 and radially between an O-ring retainer 74 and a flat washer 75 positioned inside cap 71.

A dish-shaped, Belleville spring-type diaphragm 76 has its outer edge held between washer 75 and a washer 77 and the washers are clamped between housing 70 and cap 71. An O-ring 78 is positioned within O-ring retainer 74 and has a notch 79, aligned with a notch 80 in the O-ring retainer, for each space formed between adjacent partitions 73. The edges 73a of partitions 73 are shaped to just receive and engage the diaphragm when the diaphragm seats against the O-ring in the same manner described in connection with the embodiment of FIGS. 1 and 2. In this embodiment, however,

initial high volume, low pressure flow will be through port 81 in the center of diaphragm 76, over and past the O-ring notches 79 and out the discharge ports 72. Continued pressure on the diaphragm will distort each I of the notches 79 to provide regulation of flow through each such notch into the space formed by the diaphragm, the cap and adjacent partitions 73 and out the discharge ports 72. The discharge curve through each outlet port 72 could be essentially as shown in FIG. 3. While not shown, it should be apparent that a flexible hose or other such structure can be connected to one or more of the ports 72 to convey the liquid passed therethrough to a desired point of use, either above or below ground.

Although a preferred form of my invention has been herein disclosed, it is to be understood that the present disclosure is by way of example and that variations are possible, without departing from the scope of the hereinafter claimed subject matter, which subject matter I regard as my invention.

I claim: 1. A flushing, flow control emitter unit comprising a housing;

an inlet to said housing;

an outlet from said housing;

a partition in said housing and between said inlet and said outlet;

a restricted passage across said partition;

pressure responsive means in the housing between said inlet and said outlet, said pressure responsive means being normally spaced from the partition, whereby flow from the inlet to the outlet is over said partition and said pressure responsive means being arranged to be actuated by a seating pressure at the inlet to seat on the partition, whereby flow from said inlet to said outlet is only through the restricted passage across said partition.

2. An emitter unit as in claim 1, wherein the partition is of deformable material.

3. An emitter unit as in claim 2, wherein the partition is an O-ring; and

the restricted passage comprises a notch in the sur-' face of the O-ring on which the pressure responsive means seats.

4. An emitter unit as in claim 3, wherein the pressure responsive means comprises a dish-shaped, Belleville spring-type diaphragm having a central port therethrough.

5. An emitter unit as in claim 1, wherein the pressure responsive means comprises a dish-shaped, Belleville spring-type diaphragm having a central port therethrough.

6. An emitter unit as in claim 1, wherein the pressure responsive means comprises a resilient diaphragm with a central port therethrough.

7. An emitter unit as in claim 6, wherein the housing includes a ring over which the resilient diaphragm is pre-stressed.

8. An emitter unit as in claim 1, wherein the pressure responsive means comprises a leaf spring biased away from the partition; and

means forming an orifice in the inlet, in alignment with the spring, whereby liquid entering the inlet passes through the orifice to impinge on the spring.

9. An emitter unit as in claim 1, including a plurality of outlets from said housing, each exiting from a separate compartment, and a partition and pressure responsive member between each outlet and the inlet and a restricted passage across each partition.

10. A flushing, flow control emitter unit as in claim 1, including a plurality of outlets, wall means forming with the partition and the housing, a separate compartment for each outlet, and a restricted passage across the partition at each compartment, whereby said pressure responsive member seats on the wall means and the partition.

11. A flushing flow control emitter unit comprising a tubular housing having one end adapted to be connected into a' liquid supply line;

a cap closing the other end of the housing;

a dish-shaped, Belleville spring-type diaphragm having a central port therethrough and its peripheral edge sealingly clamped between the housing and the cap;

an O-ring retainer projecting from the cap into the housing to proximate the plane of the edge of the diaphragm;

an O-ring in the retainer and projecting from the cap slightly beyond the retainer;

a notch in the O-ring at the side opposite the cap; and

seated thereon.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2938538 *Aug 16, 1956May 31, 1960Thompson Ramo Wooldridge IncFlow regulating valve
US2960109 *Jan 7, 1957Nov 15, 1960Gen Controls CoFlow regulator
US3207171 *May 9, 1962Sep 21, 1965R E Chapin Mfg Works IncBack-flow preventing valve
US3714964 *Aug 6, 1970Feb 6, 1973Factory Mutual Res CorpDouble rate flow controller
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3954223 *Jun 20, 1975May 4, 1976Rain Bird Sprinkler Mfg., CorporationTrickle irrigator
US4011893 *Feb 3, 1975Mar 15, 1977Clarence BentleyFlow control valve
US4019629 *Feb 13, 1975Apr 26, 1977Dubner Robert BPressurized tennis ball container
US4022244 *Dec 14, 1973May 10, 1977Oman William SIrrigation purge valve
US4059228 *Sep 3, 1974Nov 22, 1977Salco Products, Inc.Self cleaning, pressure responsive emitter valve for soil irrigation
US4210287 *Nov 21, 1978Jul 1, 1980Hydro-Plan Engineering Ltd.Drip irrigation system
US4382549 *Oct 22, 1980May 10, 1983Christy Mark HIrrigation emitter
US4385727 *Oct 22, 1980May 31, 1983Lloyd SpencerIrrigation emitter tube
US4464900 *Apr 28, 1982Aug 14, 1984Autmotive Products plcFlow valve
US4471812 *Mar 1, 1982Sep 18, 1984Paul BertschRemote relief-vent device
US4502631 *Mar 24, 1983Mar 5, 1985Rain Bird Sprinkler Mfg. Corp.Trickle irrigation unit
US4573640 *Dec 1, 1982Mar 4, 1986Hydro-Plan Engineering Ltd.Irrigation emitter unit
US4613080 *Jun 29, 1984Sep 23, 1986Rain Bird Sprinkler Mfg. Corp.Multiple outlet trickle irrigation unit
US4631917 *Feb 19, 1985Dec 30, 1986Wales Desmond EAir valve for improving the performance of an internal combustion engine
US4846215 *Jun 7, 1988Jul 11, 1989Marathon Oil CompanyBack pressure regulator
US4966185 *Jan 6, 1989Oct 30, 1990Henk SchramInflatable body with a valve and a packaging with such a body
US5295506 *Dec 14, 1992Mar 22, 1994Smith Allan LFlow control apparatus
US5564468 *Aug 9, 1992Oct 15, 1996Robert Bosch GmbhSeat-style pressure-relief valve
US6089272 *Feb 5, 1999Jul 18, 20003By Ltd.Check valve
US6095185 *Jul 27, 1999Aug 1, 2000Rosenberg; PeretzFluid-flow control device particularly useful as a drip-irrigation emitter
US6113369 *Jul 22, 1998Sep 5, 2000Knorr-Bremse Systems For Commerical Vehicles Ltd.Reed valve arrangement and gas compressor employing a reed valve arrangement
US6213408 *Nov 18, 1999Apr 10, 2001Eureka Technologies LtdFlow regulator and corresponding method with pressure responsive flow regulation
US6843248Apr 18, 2001Jan 18, 20053M Innovative Properties CompanyFiltering face mask that has a new exhalation valve
US6854463 *May 11, 1994Feb 15, 20053M Innovative Properties CompanyFiltering face mask that has a new exhalation valve
US7311104Apr 18, 2001Dec 25, 20073M Innovative Properties CompanyMethod of making a filtering face mask that has an exhalation valve
US7428903 *Oct 6, 2000Sep 30, 20083M Innovative Properties CompanyFibrous filtration face mask having a new unidirectional fluid valve
US7493900 *Oct 3, 2000Feb 24, 20093M Innovative Properties CompanyFibrous filtration face mask having a new unidirectional fluid valve
US7766262May 14, 2007Aug 3, 2010Gillespie Barton WIrrigation systems including flush valves, and methods for flushing debris from irrigation systems
US8302887Mar 31, 2006Nov 6, 2012Rain Bird CorporationDrip emitter
US8628032 *Dec 31, 2008Jan 14, 2014Rain Bird CorporationLow flow irrigation emitter
DE2748055A1 *Oct 26, 1977May 11, 1978Dan BronSteuergeraet fuer eine fluidstroemung
WO2001036106A1 *Nov 9, 2000May 25, 2001Eureka Tech LtdFlow regulators
Classifications
U.S. Classification137/504, 137/859, 239/542, 137/855
International ClassificationA01G25/02, F16K25/00, F16K25/02
Cooperative ClassificationA01G25/023, F16K25/02
European ClassificationF16K25/02, A01G25/02B