Low-pressure, compact, clog-resistant inline pressure-compensating flow devices for drip irrigation

Abstract

Flow devices for irrigation, also referred to as emitters or drip emitters, having improved operating parameters are disclosed. The emitters can be low-pressure and compact, designed for use within an irrigation tube or line, also referred to as inline, and can enable affordable, clean-energy technology for drip irrigation. The emitter can include a diaphragm pocket, a channel, and / or a labyrinth passage recessed within the body to regulate flow. The emitter can be designed for low activation pressure, consistent pressure compensation operation up to 4 bars of inlet pressure, and compact as compared to conventional emitters. In some embodiments, the channels of the labyrinth passage can be sufficiently wide to support superior clog resistance while having a flow-cross section that can allow a particle sized up to about 0.425 mm to flow therethrough without clogging.

Description

LOW-PRESSURE, COMPACT, CLOG-RESISTANT INLINE PRESSURE-COMPENSATING FLOW DEVICES FOR DRIP IRRIGATIONCROSS-REFERENCE TO RELATED APPLICATION

[0001] The present disclosure claims priority to and the benefit of U.S. Provisional Application No. 63 / 487,371, entitled “Low-Pressure, Compact, Clog-Resistant Inline Pressure-Compensating Drip Emitter,” filed on February 28, 2023, and U.S. Provisional Application No. 63 / 533,524, entitled “Pressure-Compensating Flow Devices for Drip Irrigation,” filed on August 18, 2023, the contents of each which is incorporated by reference herein in its entirety.FIELD100021 The present disclosure relates to flow devices for irrigation, and more particularly relates to a low-pressure, compact, clog-resistant inline pressure-compensating emitters designed to enable affordable, clean-energy technology for drip irrigation.BACKGROUND

[0003] Growing food demand, climate change, and constrained natural resources create the need for large-scale, sustainable agricultural intensification. Drip irrigation can use a network of pressurized tubing laid across the field with attached or bonded flow metering devices to ensure targeted, uniform irrigation. Use of the flow-metering devices, called emitters or drip emitters, among other terms used herein or otherwise known to those skilled in the art, can avoid water otherwise lost due to soil percolation or environmental evaporation. Despite the ability of drip irrigation to be more water efficient than traditional irrigation technologies, its adoption and retention is limited due, at least in part, to its high hydraulic equipment costs, particularly in low / middle-income countries.

[0004] Emitters used in conventional irrigation systems contribute directly to raw material costs and additionally dictate tube thickness and related material consumption. For example, conventional drip emitters can be about 1.5 inches to about 2 inches long, as discussed below, which results in use of thick wall tubes of about 1 millimeter to 1 .2 millimeters in thicknessthat are used to support the emitters disposed therein. These thick tubes increase material costs. Further, conventional emitters typically have shallow and / or narrow channels formed therein, which can lead to more frequent clogging with silt, bacteria, and microbial particles that cannot be filtered out by conventional means without intensive capital costs or significant human labor.100051 Accordingly, there is a need for a flow device for use in an irrigation system that is low-pressure, compact, and exhibits clog resistance performance.SUMMARY

[0006] The present application is directed to flow devices for use in conjunction with drip irrigation systems. The flow devices of the present embodiments can include a low-pressure, compact, clog-resistant inline pressure-compensating emitter. The emitter can include a body having a diaphragm pocket, a channel or weir, and a labyrinth forming a tortuous passage through the body. A top cover can be placed on top of the body to seal the diaphragm within the diaphragm pocket. Typically, pressure compensating (PC) inline drip emitter components can be injection molded, then welded together, and then thermally bonded to the inner wall of the drip line during tube extrusion / pultrusion itself. In some embodiments, the parameters of the emitter can be designed for low activation pressure, e.g., about 0.35 bar, consistent PC operation, e.g., up to 4 bar inlet pressure, and / or compactness e.g., about 0.85 inches long, and maintaining at least 80% of nominal flow rate while permitting passage of particles up to an approximate range of about 102 microns large to about 120 microns large. The design framework of the emitter of the present embodiments can combine parametric modeling and experimental sensitivity results to achieve the desired parameters.

[0007] One exemplary embodiment of an irrigation emitter includes a body with a volume defined between a pair of opposed walls, a pair of opposed sidewalls, and a top wall having a proximal-facing surface that is opposed to a bottom wall having a distal-facing surface. The body includes a diaphragm pocket, a lands, one or more channels formed in the lands, and a labyrinth. The diaphragm pocket is recessed into the proximal-facing surface. The lands is disposed within the diaphragm pocket that protrudes proximally from a bottom surface of the diaphragm pocket. The labyrinth is in fluid communication with the diaphragm pocket, the labyrinth forming a plurality of recessed channels within the proximal-facing surface. The emitter has an activation pressure that can be as low as 0.3 bar, a length of the labyrinth thatis no greater than 0.4 inches, and is configured to flow one of a particle sized up to about 120 microns without a significant reduction in flow rate for a pressure-compensating (PC) emitter or a particle sized up to about 400 microns without a significant reduction in flow rate for a non-pressure-compensating (NPC) emitter.

[0008] The plurality of recessed channels can include a plurality of symmetric legs disposed about a central longitudinal axis of the body, each leg comprising include at least four teeth. The labyrinth can be configured to fit within an envelope of about 0.37 inches x about 0.3 inches. A width of the labyrinth may not exceed about 0.3 inches. The one or more channels of the labyrinth can include one or more of a variable depth channel, a branching channel, or a channel with a trapezoidal cross-section. A flow rate through the channel with the trapezoidal cross-section can be substantially constant between about 0.9 L / hr to about 1.25 L / hr at pressures above 5 psi. In some embodiments, the trapezoidal crosssection can have a height (hciian) of up to about 0.010 inches and a width (wChan) of up to about 0.025 inches.

[0009] A style of the one or more channels can include one or more of a ramp-style, a branching-style, or a trapezoidal style. With respect to variable depth channels, a flow rate through a cross-section of the variable depth channel can have a radially outward slope that is approximately in a range from about 1 degree to about 2 degrees. A flow rate through a cross-section of the variable depth channel can be substantially constant between about 0.8 L / hr to about 1.4 L / hr at pressures between about 5 to about 50 psi. A hydraulic resistance of the one or more channels can increase linearly with pressure above the activation pressure to ensure a constant flow rate. A flow cross-section of the labyrinth can be approximately in a range of about 0.5 mm to about 1 mm deep and approximately in a range of about 0.59 mm to about 0.67 mm wide, with at least six (6) pairs of teeth being formed on a leg of the labyrinth.

[0010] The emitter can further include a top cover disposed above the proximal-facing surface body, with the top cover including one or more filters therein to receive a fluid from an external source. In some embodiments, the external source can be an irrigation system. The emitter can be bonded to a tube of the irrigation system at a set spacing from a second emitter having the same features as the irrigation emitter. In some embodiments, the emitter can include an inlet.

[0011] The emitter can further include a diaphragm disposed on a shelf formed within the diaphragm pocket. The diaphragm can include a silicone rubber membrane. In some embodiments, the diaphragm can be substantially circular. A shape of the diaphragm can correspond to a shape of the diaphragm pocket. The diaphragm pocket can be substantially circular.100121 One exemplary embodiment of a method of controlling flow during irrigation includes flowing a fluid into a body of an emitter, with the body having a volume that is defined between a pair of opposed walls, a pair of opposed sidewalls, and a top wall having a proximal-facing surface that is opposed to a bottom wall having a distal-facing surface. The fluid passes onto a diaphragm disposed in the body to deflect the diaphragm into a diaphragm pocket recessed into the proximal-facing surface. The fluid enters a labyrinth having a length that is no greater than about 9.5504 millimeters that is in fluid communication with the diaphragm pocket to flow through a plurality of recessed channels within the proximal-facing surface without significantly reducing a flow rate for one of fluid particles sized up to about 400 microns for a non-pressure-compensating (NPC) emitter or fluid particles sized up to about 120 microns for a pressure-compensating (PC) emitter, exits the labyrinth into a diaphragm cavity disposed below the diaphragm, and flows through a channel out of the body.

[0013] Flow rate of the emitter can be adjusted without changing activation pressure by changing a height of a lands surface, a geometry of the channel, and dimensions of the labyrinth simultaneously. A hydraulic resistance of the one or more channels can be increased linearly with pressure above the activation pressure to set a constant flow rate. In some embodiments, a device can be positioned within one or more tubes of an irrigation system such that it is in-line with a flow of fluid that passes through the one or more tubes. Positioning the device can further include thermally bonding the device to an inner wall of a drip line of the one or more tubes. In some embodiments, positioning the device can further include molding and inserting the device into the one or more tubes at set spacings. In some embodiments, fluid can pass onto the diaphragm until the diaphragm contacts a lands disposed in the diaphragm pocket that extends proximally from the distal-facing surface.100141 The channel can include one or more of a variable depth channel, a branching channel, or a trapezoidal channel. A flow rate through the channel with the trapezoidal crosssection can be substantially constant between about 0.9 L / hr to about 1.25 L / hr at pressuresabove 5 psi. In some embodiments, the trapezoidal cross-section can have a height (hciian) of up to about 0.010 inches and a width (wChan) of up to about 0.025 inches. In some embodiments, the fluid can flow through a cover having tapering oblong extrusions that make an angle approximately between about 35 degrees to about 55 degrees with the incoming flow into a tube in which the body of the emitter is disposed to create a hydrodynamic boundary layer that prevents particulate entry into an inlet of the cover and speeds up smaller particles passing between them to prevent entry into the body of the emitter.

[0015] Another exemplary embodiment of an irrigation emitter includes a body having a volume defined between a pair of opposed walls, a pair of opposed sidewalls, and a top wall having a proximal-facing surface that is opposed to a bottom wall having a distal-facing surface. The body includes a labyrinth forming a plurality of recessed channels within the proximal-facing surface. The emitter has an activation pressure that can be as low as 0.3 bar, a length that is no greater than 0.85 inches, and is configured to flow a particle sized up to about 400 microns without a significant reduction in flow rate for a non-pressure- compensating (NPC) emitter.

[0016] In some embodiments, the flow rate through the NPC emitter can range between about 1.02 to about 3.8 liters / hour at 1 bar.

[0017] One exemplary embodiment of a hydraulic system includes a pump configured to produce water using hydraulic pressure, a drip emitter of the embodiments discussed in the present disclosure, and a tube for connecting the pump to a multiplicity of drip emitters.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] This disclosure will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0019] FIG. 1A is a schematic representation of a farm in fluid communication with an irrigation system having emitters of the present embodiments disposed therein;

[0020] FIG. IB is a perspective view of an inside of a tube of FIG. 1 A having emitters of the present embodiments disposed therein;

[0021] FIG. 1C is a graphical illustration of a relationship of conventional emitter flow rate versus pressure with activation pressure highlighted, and the break-up of pump pressure in a prior art field in which emitters of the present embodiments can be used;

[0022] FIG. 2A is a perspective view of one example of an emitter of the present embodiments;

[0023] FIG. 2B is a schematic top view of the emitter of FIG. 2 A;

[0024] FIG. 3A is a partially transparent perspective view of the emitter of FIG. 2A highlighting a weir thereof;

[0025] FIG. 3B is a schematic detailed cross-sectional view of a trapezoidal weir that can be used in place of the weir of FIG. 3A;

[0026] FIG. 3C is a schematic detailed cross-sectional view of a branching weir that can be used in place of the weir of FIG. 3A;

[0027] FIG. 3D is a schematic detailed cross-sectional view of a variable-depth weir that can be used in place of the weir of FIG. 3A;

[0028] FIG. 4A is the schematic detailed cross-sectional view of the trapezoidal weir of FIG. 3B with example dimensions thereof;

[0029] FIG. 4B is a graphical illustration of a performance of flow rate versus pressure of the trapezoidal weir of FIG. 4A;

[0030] FIG. 4C is a graphical illustration of a performance of flow rate versus grit size of the trapezoidal weir of FIG. 4A;

[0031] FIG. 5A is the schematic detailed cross-sectional view of the branching weir of FIG. 3C with example dimensions thereof;

[0032] FIG. 5B is a graphical illustration of a performance of flow rate versus pressure of the branching weir of FIG. 5 A;

[0033] FIG. 5C is a graphical illustration of a performance of flow rate versus grit size of the branching weir of FIG. 5 A;

[0034] FIG. 6A is the schematic detailed cross-sectional view of the variable-depth weir of FIG. 3D with example dimensions thereof;

[0035] FIG. 6B is a graphical illustration of a performance of flow rate versus pressure of the variable-depth weir of FIG. 6A;

[0036] FIG. 6C is a graphical illustration of a performance of flow rate versus grit size of the variable-depth weir of FIG. 6A;

[0037] FIG. 7A is a perspective view of a non-pressure compensating variant of an emitter of the present embodiments, that is comprised primarily of a hydraulic labyrinth;

[0038] FIG. 7B is a detailed top view of a plurality of teeth of a labyrinth of FIG. 7A;

[0039] FIG. 7C is a chart illustrating non-limiting examples of parameters that can aide in determining properties of the labyrinth of the emitter;

[0040] FIG. 8A is a perspective view of the emitter of FIG. 2A highlighting a diaphragm pocket and a labyrinth;

[0041] FIG. 8B is a top view of the emitter of FIG. 8 A showing example dimensions thereof;

[0042] FIG. 8C is a side view of the emitter of FIG. 8A showing example dimensions thereof;

[0043] FIG. 9 is a graph illustrating flow rate through a labyrinth of the emitter of FIG. 8 A for varying parameters;

[0044] FIG. 10 is a emitter model algorithm showcasing an emitter model and flow chart used to size an emitter of the present embodiments;

[0045] FIG. 11 A is a perspective view of one embodiment of an emitter having a top cover disposed above it and illustrating an example embodiment of operation of the emitter;

[0046] FIG. 1 IB is a perspective view of the emitter of FIG. 11 A illustrating an example embodiment of operation of the emitter;

[0047] FIG. 12 is a graph illustrating a relationship of flow rate and pressure for preactivation of a diaphragm of the emitter and post-activation of a diaphragm of the emitter of the present embodiments;

[0048] FIG. 13A is a schematic perspective view of the emitter of FIG. 2A disposed inside of a tube with a flow that flows through the tube entering an inlet; and

[0049] FIG. 13B is a magnified schematic view of the inlet of FIG. 13 A having particleladen flow accelerating therethrough.DETAILED DESCRIPTION

[0050] Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will understand that the systems and methods specifically described herein and illustrated in the accompanying drawings are nonlimiting exemplary embodiments and that the scope of the present disclosure is defined solely by the claims. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present disclosure. Terms commonly known to those skilled in the art for components and / or processes of the structure, function, manufacture, and use of the devices and methods disclosed herein and the like may be used interchangeably herein. A person skilled in the art, in view of the claims, present disclosure, and knowledge of the skilled person, will understand such terms are merely examples of such components and / or processes, and other components, designs, processes, and / or actions are possible.

[0051] The present disclosure generally relates to flow devices for use in conjunction with drip irrigation systems. The types of drip emitters currently out on the market can include pressure-compensating (PC) drip emitters and non-pressure-compensating (NPC) drip emitters. At least one novel feature of the drip emitters of the present embodiments includes a low-pressure, compact, clog resistant emitter designed to be used in drip irrigation. Drip irrigation is a form of irrigation that can deliver water directly to the root zone via a network of pressurized tubing and emitters, avoiding water losses associated with conveyance andevaporation. Emitters can be flow metering devices that ensure targeted and regulated watering of crops. In some embodiments, these emitters can be positioned in-line within the tubes that flow fluid to crops by thermally bonding the emitters to the inner wall of the drip line during tube extrusion / pultrusion. The in-line emitters can be molded and inserted into the tube at set spacings and are used for growing horticultural crops.100521 FIG. 1A illustrates an irrigation system 10 that is fluid communication with a field 12 having crops 14 planted therein. As shown, the irrigation system 10 can be integrated with an off-grid solar energy system 20 that can use solar energy to pump water from a water source 30 to the field via one or more tubes 40. Targeted irrigation can involve a flow metering device disposed at each plant site. As shown, each crop 14 can be associated with a flow control device or an emitter 50. These tubes 40 can be disposed alongside the plant such that the outlet of the emitters 50 faces the root zone and ensures targeted watering. The tubes 40 and emitters 50 can be located above ground or buried alongside the plants. The tubes 40 can be manufactured to have a desired thickness (ttUbe) to allow the tubes 40 and the emitters 50 to be buried at a certain depth and / or withstand subterranean and environmental forces to prevent the tubes 40 from cracking and / or breaking.

[0053] In some embodiments, each tube 40 can include a plurality of emitters 50 disposed therein to ensure targeted and regulated watering of crops. For example, as shown in FIG.IB, the emitters 50 can be spaced a distance apart (Lemitter) within a diameter of the tube (dtube), with the spacing being based, at least in part, on the crop being grown. Conventional manufacturers may offer products with nominal emitter spacings that are one or more of, for example, 12 inches, 16 inches, 18 inches, 24 inches, and / or 36 inches, of which farmers pick a spacing that best serve their crop, crop layout, and / or harvesting plans.

[0054] FIG. 1C illustrates an exemplary embodiment of a prior art pressure breakdown in a typical field, e.g., irrigated using a surface water source such as a storage pond or tank, in which the tube 40 having the emitters 50 can be disposed. Adoption and retention of drip irrigation may conventionally be partly limited by energy demand and cost associated with using a pump to pressurize the tubes 40. PC drip emitters are passive flow control devices that have a constant outlet flow rate above a minimum inlet pressure called the activation pressure. In drip irrigation systems deployed on medium-large fields (e.g. , approximately >1 hectare) or on undulating terrains, this characteristic can be important to ensure uniform irrigation across the field because pressure variation in the drip lines can lead to significantirrigation variation to plants. Conventional PC emitters do not support low-pressure operation. Specifically, conventional PC emitters may have an activation pressure (Pact) in the range of 0.4 bar to 1.0 bar, which requires pump size and energy demand to be sufficient to ensure that the farthest emitter in a group of emitters is at least able to achieve its activation pressure to ensure irrigation uniformity. That is, the activation pressure can be a large component of pump pressure of the irrigation system that is being used. For example, as shown for the field of FIG. 1C, a pump pressure of at least 2.0 bar is used to maintain a Pact of 1.0 bar in the emitter due, at least in part, to the presence of pipe friction loss (0.4 bar) and filters, fertilizer tanks, and so forth (0.6 bar). Reducing activation pressure to be less than about 0.5 bar, less than about 0.4 bar, and / or less than about 0.35 bar, as in the emitters of the present embodiments, can reduce energy costs of pump operation and reduce the pump pressure used in the drip irrigation system while ensuring irrigation uniformity.

[0055] FIGS. 2A-2B illustrate the emitter 50 of the present embodiments in greater detail. The emitter 50 of the present embodiments can include at least three novel aspects that distinguishes the emitter from conventional drip irrigation components: i) pressurecompensating, clog-resistant weirs / channels; ii) compact labyrinth design; and iii) a novel inlet design.100561 As shown, the emitter 50 can include a body 51 having a diaphragm pocket 52 configured to receive a diaphragm 53 therein. The body 51 can be made from made from low- or high-density polyethylene As shown, the diaphragm pocket 52 can be circular, though it will be appreciated that in some embodiments, the diaphragm pocket can be rectangular, or alternate shapes. The diaphragm 53 (as seen in FIGS. 11A-1 IB) can be made of silicone rubber or any other elastomeric material or membrane that can be disposed within the diaphragm pocket. The diaphragm pocket 52 can include a seat or ledge 58 for placement of the diaphragm 53. The bottom surface of the diaphragm pocket 52 can include a lands 54 with a channel or weir 56 embedded in it. As inlet pressure above diaphragm 53 increases, the diaphragm 53 deflects towards the lands 54 to a degree such that contact may occur therebetween. In such embodiments, the channel / weir 56 can form the only flow passage for water. Increasing pressure may increase interaction or contact between the diaphragm 53 and the lands 54, thereby modulating the channel / weir 56 hydraulic resistance, ensuring that the flow rate is constant (or at least substantially constant, with a person skilled in the art being understand what constitutes a constant or substantially constant flow rate). The lands 54 canhave a single straight channel / weir or multiple or a branching geometry. The lands 54 can be raised above the bottom of the diaphragm pocket 53 to provide flow area around the channel / weir 56 where particles that otherwise may block the channel / weir 56 may collect safely. The channel / weir 56 can terminate at an outlet 57 that is defined by the lands 54 within the diaphragm pocket 52 to allow water to flow out of the emitter 50, as discussed below. The present design is such that the emitter 50 can be easily configured to run at different flow rates. The depth of the diaphragm pocket 52 can be fixed across multiple flow rates, so that the height of the lands 54 above the diaphragm pocket 52 bottom and crosssection of the weir / channel 56 can be adjusted to tune pressure and flow rate at which the diaphragm 53 may contact the lands 54. In some embodiments, the emitter 50 can include a welding rib 55 for welding with a top cover (as seen in in FIG. 8A, for example). The welding rib 55 can ensure a targeted, leak- free welding joint between emitter body and cover, unlike prior designs which may involve an emitter body-cover weld that encompasses the free surface area of the emitter. This can ensure that welding does not produce excessive plastic flash or melt that could enter the flow passages and hamper manufacturing uniformity. Additionally, the welding rib 55 can limit the size of the heat affected area during the welding process, which may reduce the risk of molded features being thermally deformed during welding. Emitters can maintain a constant flow rate using these weirs or channels 56 that can have a depth approximately in a range of about 10 microns to about 250 microns, approximately in a range of about 50 microns to about 250 microns, and / or approximately in a range of 10 microns to about 100 microns.

[0057] To achieve the desired volume use and hydraulic performance (activation pressure and rated flow rate), the emitter 50 can be parametrically modeled to increase the efficiency of the emitter architecture. For example, modeling the contact between the lands 54 and the diaphragm 53 can be difficult in two-dimensions. To simplify this modeling, circular shaped diaphragms can be used, whose axis symmetry allows the contact problem to be onedimensional, and hence more tractable. This increase in tractability can then influence other components of the emitter. This model can simulate and / or estimate flow rate vs. pressure as a function of geometry and material property, which can then be put together in an Ohm’s law approach to formulate flow rate as a function of pressure. Further, one or more components can be parametrically modeled. For example, the channel 56 of the present embodiments can be pressure-compensating and / or clog resistant. In some embodiments, the channel 56 can be modeled via analytical models and / or Computational Fluid Dynamics(CFD) to include geometries, e.g., ramp-style, branching- style, and / or trapezoidal style, which can improve emitter performance as compared to conventional emitters.

[0058] It will be appreciated that the geometry of the channel or weir 56 can assist in making the present design more clog-resistant than predecessor designs. The minimum depth of the channel / weir 56 can be set to ensure that particles smaller than 125 microns may easily pass through the channel / weir 56 while larger particles may not enter. FIGS. 3A-3D illustrate exemplary embodiments of the emitter 50 and several channel / weir designs having a rectangular weir 56, trapezoidal weir 56', a branching weir 56", and a variable-depth weir 56"', respectively. As shown in FIG. 3B, the trapezoidal weir 56' can have a cross-section in which the angle between the side walls of the weir / channel and diaphragm is an acute angle. This angle can support a larger hydraulic resistance than a rectangular cross-section weir of the same depth. In the present embodiment, this can allow the weir / channel depth to be deeper than an equivalent rectangular cross-section weir / channel, which may enhance clogging resistance. In the branching weir 56", as shown in FIG. 3C, two or more branches 56a", 56b" can merge into a single passage. Even if one of the multiple branches (e.g., 56a") at the channel / weir 56" entry clogs due to, for example, particle entry, the remaining branches (e.g., 56b") may permit desired flow rate without a loss in performance. The geometry of the branches can be selected such that the depths or widths of the branches 56a" and 56b" are distinct from the depth or width of the merged branch to ensure that pressurecompensation is achieved along with clog resistance. In the variable-depth weir 56"' configuration, as shown in FIG. 3D, the weir can have a rectangular cross-section that can be used for consistent performance up to about 4 bar, in which the channel or weir 56 can include a variable-depth weir that slopes at an angle of approximately 1.66°, e.g., has a sloped floor, from about 0.002 inches to about 0.004 inches in the radially outward direction, which can create sustained PC action up to 4 bar inlet pressure. Characteristics of the variable-depth weir 56’" are discussed in greater detail below. In some embodiments, a flow rate through a variable depth cross-section weir having a radially outward slope can be approximately in a range from about 1 degree to about 2 degrees. Moreover, a flow rate through a cross-section of the variable depth weir can be substantially constant between about 0.8 L / hr to about 1.4 L / hr at pressures between about 5 to about 50 psi

[0059] FIG. 4A illustrates the trapezoidal weir 56' of FIG. 3B with exemplary dimensions for a height of the trapezoidal cross-section (hChan) of the trapezoidal weir 56' of 0.0065inches and width of the trapezoidal cross-section (wChan) of the weir 56' of 0.016 inches, and FIGS. 4B-4C illustrate the performance of the trapezoidal weir 56' of these example dimensions. In some embodiments, the height of the trapezoidal cross-section (hchan) of the trapezoidal weir 56' can be up to about 0.010 inches and the width (wchan) can be up to about 0.025 inches. As shown, performance of the trapezoidal weir 56' can be such that the fluid boundary layer interaction of the acute corners of the trapezoidal cross-section can create significant hydraulic resistance allowing desired flow rate to be maintained, while also simultaneously allowing for a deeper cross-section than a hydraulically equivalent rectangular cross-section, so that it may be resistant to clogging up to a larger sized particle than conventional emitters. As shown in FIG. 4B, such a channel / weir can maintain a substantially constant flow rate as pressure increases, with less than 10% change in flow rate as pressure increases from about 5 psi to about 25 psi. From a clogging perspective, a test in which progressively larger particles are added to emitter inflow shows that the trapezoidal channel / weir may permit particles up to 120 US mesh grit size (102 microns) without substantial clogging as shown in FIG. 4C. After fully clogging, the weir / channel can permit up to 20% recovery in flow if the pressure at its inlet is stopped and restarted. The result is that this weir / channel geometry can help the emitter simultaneously achieve substantial pressure-compensation while resisting clogging, all while being contained within a substantially more compact physical envelope.

[0060] FIGS. 5A and 6A illustrate the branching weir 56" of FIG. 3C and the variabledepth weir 56"' of FIG. 3D of the listed dimensions, respectively. Further, FIGS. 5B-5C illustrate the performance of the branching weir 56" of these example dimensions, and FIGS. 6B-6C illustrate the performance of the variable-depth weir 56'" of these example dimensions. For example, as shown in FIG. 5B, performance of the branching weir 56" can be such that the flow rate through such an emitter increases from about 0.9 L / hr to about 1.5 L / hr over a pressure range of about 5 to about 50 psi.. In a clogging test, the branching / channel weir can also permit particles up to 100 US mesh grit size (122 microns) while having just approximately 40% decrease in nominal flow rate. Upon restart after fully clogging, the branching weir 56" can recover approximately 30% of its nominal flow rate. By introducing a redundant entry to the main weir / channel, the branching geometry can help the emitter permit passage of particles that can be up to about 20 microns larger in size than the trapezoidal weir / channel 56' without substantial clogging. In the current example, thismay come at the expense of a slight decrease in pressure-compensating ability, which may be acceptable over small-medium farms.

[0061] Performance of the variable-depth weir 56"', as shown in FIG. 6B, can be such that the flow rate rises from approximately about 0.9 L / hr to about 1.25 L / hr between approximately 5 psi and approximately 50 psi.. In a clogging test, this weir / channel can maintain up to about 80% of its nominal flow rate while permitting passage of particles as large as 100 US mesh openings (122 microns) and recovering up to about 40% of its nominal flow rate upon a pressure restart. In another embodiment of this geometry the depth of the weir / channel can be uniformly reduced by about 0.0015 inches without changing the angle to improve the pressure compensation.

[0062] LABYRINTH

[0063] While a PC emitter may include a turbulent labyrinth, a hyperelastic rubber diaphragm that interacts with a lands and channel / weir, FIG 7 A shows how an NPC emitter may include a single molded body with a turbulent labyrinth that provides a constant hydraulic resistance. As shown in FIG. 2B, for example, the diaphragm pocket 52 of the PC emitter 50 of the present embodiments can be in fluid communication with a labyrinth 60 that forms a tortuous passage within the body of the emitter 50 to flow fluid through the emitter, as discussed in greater detail below. The labyrinth 60 can have one u-tum, as shown, though, in some embodiments, two or more u-tums are possible. In some embodiments, the body 51 can include a transfer channel or transfer port 61 (as seen in FIG. 2B) connecting an exit of the labyrinth 60 and the diaphragm pocket 52. As shown, in some embodiments, the transfer channel 61 can be disposed on a bottom side (or the like) of the emitter 50 such that a person skilled in the art will recognize how such a configuration of the transfer channel 61 can be implemented within the emitter 50 in view of the figures provided and knowledge of the skilled person to transfer water flowing through the labyrinth 60 into the diaphragm pocket 52. Water flow through the transfer channel is discussed in greater detail in FIGS. 11 A-l IB below. The labyrinth 60 in the emitter 50 can be configured to control and / or regulate an activation pressure and / or a rated flow rate through the emitter 50, while being compact and having exceptional clog resistance performance. For example, in some embodiments, the labyrinth 60 can allow the activation pressure of the emitter 50 to be about 85% lower than a conventional commercial product.

[0064] FIGS. 7A-7C illustrate a geometry of the body 51 of an emitter 50' having a tractable labyrinth 60'. The labyrinth 60' can be a zig-zag flow feature designed to create pressure loss through turbulent energy dissipation. Functionally, labyrinths perform akin to orifices, i.e., flow rate oc pressure1'2. This relationship can allow labyrinth hydraulic performance to be defined by the constant of turbulent hydraulic resistance, Kiab = (AP / Q2), where AP is the pressure drop across the labyrinth, Q is the flow rate in m3 / s, and Kiab is presented in kg / m7. In some embodiments, the labyrinth 60 can be a standalone NPC emitter package.

[0065] As shown, the labyrinth 60 can be split into two substantially symmetric legs 74' disposed about a central longitudinal axis L of the body 51 ' having a sequence of staggered teeth-like structures or teeth 70' (seen in FIG. 7B). The fluid flow that passes through the labyrinth 60' can be adjusted to flow around or past these teeth 70'. This flow can create recirculation zones between the teeth 70', which can be an integral feature of the labyrinth 60'. In some embodiments, the overall length and width of each leg 74' can be restricted by the target volume consumption and cover-body welding considerations. As a result, the emitter 50', much like the emitter 50, can include one or more clearances or spaces 59' around one or more edges of the body 51' to accommodate for welding of the body 51' and a top cover 62 (as shown in FIG. 8A, for example).

[0066] As shown in FIG. 7B, a shape of the teeth 70' can be triangular. The exact shape of the teeth 70' may be dictated, at least in part, by space available to fit sufficient teeth to adequately regulate fluid flow as well as limits of injection molding, among other factors. The sharpness of the tooth 70' can be limited by mold venting limits, resulting in a rounded tip with a minimum achievable radius of about 0.0025 inches (63.5 microns). Moreover, the emitter 50' can include a space 72' for alignment pins (as seen in FIG. 2A), welding ribs, stop posts, and so forth, the purpose of which, at least in view of the present disclosure, are understood by a person skilled in the art. In some embodiments, these modifications can result in the entire labyrinth 60' fitting within approximately 9 millimeters of the emitter 50', while having sufficient hydraulic resistance to achieve approximately 1 L / hr at 1 bar of pressure, which is a commercially valuable flow rate. It will be appreciated that while the teeth 70' are discussed with respect to emitter 50', these parameters and / or measurements can be applied to emitter 50, as well as other emitters provided for herein, emitters derivable in view of the present disclosure, or emitters known to those skilled in the art.

[0067] In some embodiments of the labyrinth 60', its geometry, and hence fluid resistance, may be determined by at least 14 parameters including aforementioned clearances (tabulated in bold in FIG 7C), making its design procedure complicated. Some non-limiting examples of these parameters are shown in FIG. 7C and are illustrated in FIGS. 7A and 7B. These parameters can define the various dimensions of the teeth 70', e.g., tooth triangle height (btooth), tooth tip gap (btip), and / or tooth triangle base length (Ltoothbase), among others, which can impact tooth spacing (Lspace), labyrinth length (Liab), and so forth. In some embodiments, consolidation of the manufacturing limits, material volume consumption target, and / or near- symmetric embodiment enable the effect fluid resistance of the labyrinth to be determined by three parameters only: tip gap (btiP), labyrinth depth (hiab), and number of teeth (Nteeth), greatly simplifying adjustment of labyrinth 60' to achieve different target flow rates, as discussed below. Other parameters that can determine properties of the labyrinth 60', and hence the emitter 50', are shown in FIG. 7C, but are often constrained by manufacturing and / or practical considerations. In some embodiments, flow rate of the emitter 50' can be adjusted without changing activation pressure by changing the height of the lands surface, channel geometry, and dimensions of labyrinth simultaneously.

[0068] The labyrinths 60, 60' of the present embodiments can be used in a PC and / or an NPC emitter. Values for hydraulic resistance and the like can be based on the various parameters of the labyrinths 60, 60', but this process can be simplified by leveraging symmetry, manufacturing, and / or practical considerations such as clogging. In the current embodiments, for example, the labyrinth geometry can be adjusted using just three (3) out of the 14 distinct parameters: the number of teeth (Nteeth); tooth tip gap (btiP); and labyrinth depth (hiab), with the depth being measured by a distance in which the labyrinth 60' is recessed into the body 51'. Along the length of the emitter body, the number of teeth (Nteeth) times the sum of tooth base length and tooth spacing in each leg 74' can be the overall length which can be ideally minimized to reduce overall plastic mass of the emitter, thus placing an indirect tradeoff consideration between number of teeth (Nteeth) and tooth triangle base length (LtOothbase). In some embodiments, the tooth count can be selected to be six (6) per side to have reasonably shaped teeth with adequate spacing for particles, which can be increased or reduced by adjusting the gap between the teeth to adjust the resistance using the proportional relation: Kiaboc Nteeth. Along the width, the tooth tip gap (btiP) and twice the tooth triangle base height (btooth) can add up to be the width of one leg 74' of the labyrinth 60', which may be restricted, for example, to ensure that the labyrinth fits within a typical drip irrigation tubewithout being a significant impediment to overall flow. Recognizing that it is the tooth tip gap (btip) that affects hydrodynamic behavior, the tooth triangle base height (btooth) can therefore be set indirectly. In some embodiments, the tooth tip radius (rtip) can be sought to be minimized based on aforementioned injection molding venting limits, e.g., an injection molding limitation of about 0.0025 inches. In some embodiments, the tooth tip gap (btiP) of the labyrinth 60' can be about 0.000 to about 0.004 inches.

[0069] FIGS. 8A-8C illustrate perspective, top, and side views, respectively, at least for purposes of providing non-limiting, example dimensions of the emitter 50. It will be appreciated that these dimensions are merely examples, and one or more of the lengths, widths, depths, spacings, and / or other measurements of the emitter being capable of manufacture larger and / or smaller than indicated.

[0070] FIG. 9 illustrates a flow rate graph for the labyrinths 60, 60' of the present embodiments. As shown, the flow rate, and therefore the labyrinth hydraulic resistance, can be impacted by one or more of depth (hub) or tip gap (btip). The depth (hiab) and the tip gap (btip) can be adjusted to measure flow rate and a polynomial fit can be determined to calculate flow rate values at each combination of depth (hiab) or tip gap (btiP). As mentioned above, these adjustments alongside adjustments in lands depth and weir / channel cross-section can allow for example, in some embodiments, a flow rate of fluid supported through the PC emitter can be approximately in a range of about 1 liter / hour to about 4 liters / hour, approximately in a range of about 1.5 liter / hour to about 4 liters / hour, and / or approximately in a range of about 1.5 liters / hour to about 2 liters / hour. A flow rate supported through the NPC emitter can range between about 1.16 liters / hour to about 3.8 liters / hour at 1 bar.

[0071] Compactness of the emitter 50 can be achieved by decreasing overall length of the emitter body 51. The overall length, in turn, can be driven, at least in part, by the size of the diaphragm pocket 52, length of the labyrinth 60, and / or clearances 59 for top cover-emitter body welding, the latter of which is driven by manufacturing considerations. Further, the width of the emitter body 51 (bemitter) may be considered equal to the sum of the diaphragm seat 58 diameter and clearance around the seat 58. As shown and described herein, the emitter 50 can have a width that fits within typical tubing 40 without creating significant obstruction to flow. This can allow the width, and therefore the diaphragm seat 58 outer diameter, to be set to its maximum value. Thus, the variable or adjustable aspect of the length of the emitter body 51 may be considered to be the length (Liab) of the labyrinth 60alone. Commercial emitters comparable to emitter body 51 presented herein may typically have labyrinth lengths in the range of about 16 mm to about 24 mm. In contrast, in some embodiments, the labyrinth 60 of the present embodiments can have a length that is approximately in a range of about 9 mm to about 10 mm, or have a singular length that is approximately 0.4 inches, or approximately 0.376 inches (i.e., about 9.5504 mm long).100721 As shown, in the illustrated embodiment, the labyrinth 60 can make up a large portion of the body 51 of the emitter 50, e.g., about 40% to about 50% of the emitter 50, with a length LI of the emitter 50 being approximately between about 0.8 inches and 1 inch, or about two (2) times to about 2.5 times greater than the labyrinth length (Liab), and a width (bemitter) of the emitter 50 being about 1.25 times to about 1.75 times greater than a width (biab) of the labyrinth 60, when including clearances for cover-emitter body welding, etc. In some embodiments, for example, the labyrinth length (L^b) can be about 0.376 inches, or 9.56 millimeters, while a width of the labyrinth (biab) can be less than about 0.297 inches, or 7.54 millimeters. The remaining dimensions of the emitter 50 are shown in FIGS. 8B-8C, with one or more of these dimensions being customizable relative to the others to regulate flow rate, hydraulic resistance, and the like, as discussed above.

[0073] In some embodiments, a length of the labyrinth 60 does not exceed about 9.5 mm (or about 0.37 inches) and a width of the labyrinth 60 does not exceed about 7.54 mm (or about 0.3 inches). As a result, the PC emitter 50 using this compact labyrinth can use significantly less raw material than comparable products to prepare, allowing for a direct decrease in up-front cost of production. For example, the presently disclosed emitter 50 can represent up to about 59.5% material volume saved compared to Toro BlueLine 1.0 L / hour PC emitter, which can serve as a comparable commercial product. The Toro BlueLine 1.0 L / hour PC emitter is two (2) inches long. Tuning the tip gap can allow the depth of the current labyrinth 60 to be about 0.68 mm as compared to a comparable product from Dripnet PC that has a depth of about 0.6 mm for the same product flow rate. This extra depth can result in a significant improvement in clog resistance. For example, the labyrinth 60 can be designed to allow particle sizes of about 0.4 mm diameter to pass therethrough. That is, when added to the PC emitter, while the labyrinth permits 0.4 mm large particles, the maximum particle size of the aforementioned weir / channel limits can be limited to about 100 microns to about 120 microns.

[0074] The labyrinth 60 can be a volume-intensive component of the drip irrigation emitter 50, and thus labyrinths as provided for herein can be a volume-intensive component of drip irrigation emitters. For example, the labyrinth 60 of the present embodiments can have a hydraulic resistance that can support low activation pressure (e.g., which can be defined as 0.4 bar or lower for the purposes of this disclosure), though the activation pressure can go as low as 0.3 bar, and can be compact (fits within an envelope of about 0.37 inches by about 0.3 inches). It will be appreciated that, in some embodiments, low activation pressure can be achieved by increasing the diameter of the diaphragm 53, but this is practically limited by the overall width of the emitter body (bemittei) and the clearances. Moreover, clog resistance of the emitters of the present embodiments can be measured by particle size of which the labyrinth supports flow therethrough. In some embodiments, the labyrinth 60 can include a tooth tip gap (btip) of between about 0 mm and about 0.15 mm and a flow cross-section that at any point that is deeper than 0.6 mm (0.027 inches), with a 0.4 mm minimum face gap between adjacent teeth to support superior clog resistance as compared to conventional emitters. For example, the flow-cross section can allow a particle sized up to about 0.42 mm (corresponding to 40 US mesh, the coarsest available irrigation filter) to pass through the labyrinth 60 without significantly reducing a flow rate through said labyrinth 60. One having skilled in the art will recognize that conventional emitters are listed to use 80 US mesh or 120 US mesh, which highlights the superior clog resistance of the presently disclosed labyrinth. It will be appreciated that for the purposes of this disclosure, “without significantly reducing a flow rate” can refer to the emitter maintaining at least 80% of nominal flow rate, or more than 20% reduction in flow rate relative to nominal flow rate. In some embodiments, a flow cross-section of the labyrinth can be approximately in a range of about 0.5 mm to about 1 mm deep and approximately in a range of about 0.59 mm to about 0.67 mm wide, while having at least six (6) pairs of teeth on a single labyrinth passage or leg 74 that is no more than 0.4 inches long (about 10 mm long), or 0.37 inches long (about 9.5504 mm long).

[0075] DESIGN PROCESS AND OPERATION

[0076] The emitters of the present embodiments can exhibit several novel elements as compared to conventional emitters. For example, the design process for the emitter(s) can include a hybrid analytical-experimental design framework where the diaphragm pocket, which is geometrically one-dimensional, can be modeled analytically, while the labyrinth 60 can be designed using aforementioned experimental sensitivity studies informed bymanufacturing topology constraints. The hybrid analytical-experimental approach can allow leverage of the speed of the model and quantitative indicators of the sensitivity studies to reduce the number of test prototypes for design of the emitters.

[0077] Another novel aspect of the present disclosure is that, unlike prior design approaches that either designed emitters using a trial- and-error approach or were unable to model the contact mechanics between the diaphragm 53 and the lands 54, the presently disclosed techniques can use a numerical algorithm to linearize the nonlinear governing physics of emitter operation using an iterative scheme. FIG. 10 illustrates an exemplary embodiment of an emitter model algorithm that can be used for such modeling. By using an iterative loop in which an assumed deflected shape for the diaphragm is used to calculate the flow rate, which in turn helps better evaluate the deflected shape, the algorithm can help segment the structural and fluid mechanical aspects of emitter operation to serve as a direct, physical model of the emitters. Once sufficient iterations are performed at a single pressure, or flow rate variation between subsequent iterations is minuscule, for example <1%, the algorithm can move to the next pressure point. Difference between pressure points is typically 0.01 bar to 0.05 bar, with deflection from the previous pressure point can be used as an initial guess for the next pressure point. If the inlet pressure (Pi) is greater than the maximum pressure (Pmax), the run can be ended, the final pressure and flow rate can be inspected, and deflection plots can be created.

[0078] For example, as discussed above, the hydraulic resistance of the channel 56 can be designed to increase linearly with pressure above the activation pressure to ensure a constant flow rate. In conventional emitter designs (e.g., emitters from Netafim, Toro, Rainbird, etc.), the resistance of the channel can be a function of both contact radius / length between diaphragm and lands and the extent of diaphragm shear into the channel. The diaphragm shear in conventional designs can use extensive coupled computational simulations to characterize and is challenging to customize for a target performance, be it hydraulic or clogging based. To avoid this complexity, a shear-resistant channel / weir flow passage can be used in the emitter 50 of the present embodiments. This channel can be intentionally sized to prevent the shearing of the diaphragm 53 into it. In such embodiments, the resistance can be dependent at least in part on the contact radius / length and the cross-section of the channel 56, thereby removing the complexity of shear from the design. In some embodiments of theshear-resistant channel, the width of the channel 56 can be limited to about 0.33 mm and the depth can be limited to at least about 0.05 mm.

[0079] FIGS. 11 A-l IB illustrate the operation of the emitter 50 via steps enumerated (1 )- (6), with steps ( 1 )-(3) illustrated in FIG. 11 A and steps (4)-(6) illustrated in FIG. 1 IB. For the purpose of operation, in some embodiments, such as those shown in FIG. 11 A, the emitter 50 can include a top cover 62 or seal that rests on top of the body 51 to prevent fluid from escaping therefrom and ensures that fluid flow moves progressively through the flow features without leaking or bypassing any regions. The top cover 62 may also include features that interface with the emitter 50 production line, enabling handling and conveyance. In the illustrated embodiment, the top cover 62 is shown as being spaced apart from the body 51 , though this is done primarily for illustrative purposes and in use the cover is typically coupled to the body 51 using any number of known coupling techniques, such as laser welding or ultrasonically welding the top cover 62 to the body 51. In some embodiments of the emitter body 51 , clearances around hydraulic features can be sized to support both laser and ultrasonic welding. The top cover 62 can include a filter 63 therein for allowing water from a pump of the system 20 to pass into the emitter 50.

[0080] At the start of operation, as shown at step (1), the water can enter the emitter 50 through the diaphragm pocket 52 through the inlet 63 and / or filter(s) 64 in the top cover or seal 62, with the filter being discussed in greater detail below. The water can be traveling from and / or as directed by a pump (not shown). The water can push and / or deflect the diaphragm 53 down towards and / or onto the lands 54, as indicated at step (2). From the diaphragm pocket 52, the water can be directed to enter the tortuous path of the labyrinth 60, as indicated at step (3). The zig-zag nature of the labyrinth 60 can promote turbulence which can dissipate energy, thereby decreasing losing pressure as it travels through the labyrinth 60.

[0081] Turning to FIG. 1 IB, as indicated at step (4), the low-pressure water can enter the diaphragm pocket 52 below the diaphragm 53 via the transfer channel or transfer port 61, in which a difference in pressure above and below the diaphragm 53 can cause it to deflect towards bottom of the cavity. In turn, the diaphragm 53 can contact the lands 54. This can occur at or around the activation pressure at which point the pressure drop across the labyrinth (and therefore top and bottom of the diaphragm) is given by:where Qrated isthe desired flow rate of the emitter. In this manner, the labyrinth is central to supporting the pressure-compensating operation of the emitter.

[0082] Prior to contact between the diaphragm 53 and the lands 54, a flow rate of the emitter 50 can rise with a square root of the inlet pressure. Once contact is established, the flow can be forced through the weir / channel 56 in the lands 54, whose flow resistance can increase linearly with pressure, which can keep outlet flow rate constant, as indicated at step (5). A length of the channel 56 can be a radius of contact patch of the diaphragm 53 and the lands 54, as shown at step (6). For a low flow rate emitter, which can be desirable for at least certain plants, this effective load on the diaphragm 53 can be diminished (since Qrated islow), creating activation at high pressure. To reduce the activation pressure, which may be desirable for cost-constrained settings or to support the affordable integration of solar energy sources, a high hydraulic resistance labyrinth can be created to compensate for the low rated flowrate. A high resistance labyrinth can be achieved through the use of diminutive flow features through which flow is squeezed (which may be clog-prone) and / or a voluminous labyrinth that may be wide but has enough repeating units to create a given resistance (which may be material intensive). In the current embodiment, the labyrinth 60 can be designed by adjusting tip gap (btiP), depth (hiat>), and number of teeth (Nteeth), as discussed above, to support a low flow rate of 1 liter / hour despite fitting within an envelope of about 0.37 inches by about 0.3 inches, and having passage area for large particles (at least up to 400 micron or 40 mesh filter compatible in the case of an NPC emitter) to pass through.

[0083] FIG. 12 illustrates the relationship of flow rate and pressure pre-activation and postactivation in greater detail. As shown, pre-activation, such as when the pressure in the emitter 50 is lower than the activation pressure (Pact), flow rate can increase with pressure, such as between steps (1) and (2) of FIG. 11 A, in which the water has entered the emitter 50 but the diaphragm 53 has not yet been sufficiently deflected to contact the lands 54. This creates hydraulic resistance values as shown in (i). Once the diaphragm 53 contacts the lands 54 in step (2), pressure is greater than activation pressure (Pact), and the flow rate can be constant against pressure, with channel resistance increasing with contact radius between the diaphragm 53 and the lands, as shown in (ii).

[0084] The emitters 50 of the present embodiments can consistently operate to pressure regulate in approximately a range between about 0.3 bar (4.35 psi) and about 4 bar (58 psi), while comparable conventional emitters can only pressure regulate up between 0.4 bar (6 psi)to 3.5 bar (51 psi). The wide pressure range can allow the emitter 50 to be used over a range of field sizes from small fields (e.g., approximately 800 ft. on side), to large fields, where high pump pressures are more likely to be operated where the low activation pressure can help reduce lifetime electricity / solar costs for affordable operation.

[0085] As discussed above, the emitter 50 can include the inlet 64 formed in the top cover 62 to help prevent entry of foreign particles into the emitter, thereby improving clogging performance thereof. For example, FIGS. 1 A-13B illustrate the emitter 50 disposed in the tube 40, e.g., a drip tube, with a particle-laden flow 71 that flows through the inlet 72. A detailed view of the inlet is shown in FIG. 13B. As shown, the inlet 64 can be located on the top cover 62, for instance above the center of the diaphragm 53. Rather than relying on geometric dimensions to keep contaminants out, which are ineffective and still allow silt, bacteria, and microbials, among other contaminants, to pass therethrough, the inlet 64 of the present embodiments can use hydrodynamic effects to filter out contaminants. The inlet can include football- shaped extrusions 76, which can form a nozzle-shaped cross section between them and are at an angle to the bulk flow 71 in the tube. Water can enter the tube through the gap between the nozzles 64 seen in FIG. 13B. The designs of the inlet 64 of the present embodiments can leverage hydrodynamic effects for clog resistance. For example, the inlet 64 can include nozzle-style and manta-ray style designs 76 that can allow improved filtration of particles to prevent clogging of the emitter 50. The leading edge of the football fins 76 can create a fluid boundary layer that may deflect a number of particles that would otherwise enter the emitter via inlet 64. The angle of the football fins 76 can create a preferential direction for water to flow past and into the emitter. The downstream side of the inlet may force water to spiral about the axis of the tube, creating a dirty corkscrew flow created at the outlet 74 of the tube 40. The primary hydraulic of the inlet depend on an angle of attack, 0, which may center approximately around 45 degrees, and / or be in approximately a range approximately between about 35 degrees to about 55 degrees. For example, in some embodiments, the top cover 62 can have tapering oblong extrusions that make an angle approximately between about 35 degrees to about 55 degrees with the incoming flow into the tube in which the emitter body 51 is disposed to create a hydrodynamic boundary layer that prevents particulate entry into the inlet 64 and speeds up smaller particles passing between them to prevent entry into the emitter body 51.

[0086] Examples of the above-described embodiments can include the following:1. An irrigation emitter, comprising: a body having a volume defined between a pair of opposed walls, a pair of opposed sidewalls, and a top wall having a proximal-facing surface that is opposed to a bottom wall having a distal-facing surface, the body including: a diaphragm pocket recessed into the proximal-facing surface; a lands disposed within the diaphragm pocket that protrudes proximally from a bottom surface of the diaphragm pocket; one or more channels formed in the lands; and a labyrinth in fluid communication with the diaphragm pocket, the labyrinth forming a plurality of recessed channels within the proximal-facing surface, wherein the emitter has an activation pressure that can be as low as 0.3 bar, a length of the labyrinth that is no greater than 0.4 inches, and is configured to flow one of a particle sized up to about 120 microns without a significant reduction in flow rate for a pressurecompensating (PC) emitter or a particle sized up to about 400 microns without a significant reduction in flow rate for a non-pressure-compensating (NPC) emitter.2. The emitter of example 1, wherein a hydraulic resistance of the one or more channels increases linearly with pressure above the activation pressure to ensure a constant flow rate.3. The emitter of example 1 or example 2, wherein a flow cross-section of the labyrinth is approximately in a range of about 0.5 mm to about 1 mm deep and approximately in a range of about 0.59 mm to about 0.67 mm wide, with at least six pairs of teeth being formed on a leg of the labyrinth.4. The emitter of any of examples 1 to 3, further comprising a diaphragm disposed on a shelf formed within the diaphragm pocket.5. The emitter of example 4, wherein the diaphragm includes a silicone rubber membrane.6. The emitter of example 4 or example 5, wherein the diaphragm is substantially circular.7. The emitter of any of examples 4 to 6, wherein a shape of the diaphragm corresponds to a shape of the diaphragm pocket.8. The emitter of any of examples 1 to 7, wherein the diaphragm pocket is substantially circular.9. The emitter of any of examples 1 to 8, wherein the labyrinth is configured to fit within an envelope of about 0.37 inches x about 0.3 inches.10. The emitter of any of examples 1 to 9, wherein a width of the labyrinth does not exceed about 0.3 inches.11. The emitter of example 1 , wherein the one or more channels comprises one or more of a variable depth channel, a branching channel, or a channel with a trapezoidal cross-section.12. The emitter of example 11, wherein a flow rate through the channel with the trapezoidal cross-section is substantially constant between about 0.9 L / hr to about 1.25 L / hr at pressures above 5 psi.13. The emitter of any of examples 11 to 13, wherein the trapezoidal cross-section has a height (hchan) of up to about 0.010 inches and a width (wchan) of up to about 0.025 inches.14. The emitter of any of examples 11 to 13, wherein a flow rate through a cross-section of the variable depth channel having a radially outward slope is approximately in a range from about 1 degree to about 2 degrees.15. The emitter of any of examples 11 to 13, wherein a flow rate through a cross-section of the variable depth channel is substantially constant between about 0.8 L / hr to about 1.4 L / hr at pressures between about 5 to about 50 psi.16. The emitter of any of examples 1 to 15, wherein the plurality of recessed channels comprises a plurality of symmetric legs disposed about a central longitudinal axis of the body, each leg comprising include at least four teeth.17. The emitter of any of examples 1 to 16, further comprising a top cover disposed above the proximal-facing surface body, the top cover including one or more filters therein to receive a fluid from an external source.18. The emitter of example 17, wherein the external source is an irrigation system.19. The emitter of example 18, wherein the emitter is bonded to a tube of the irrigation system at a set spacing from a second emitter having the same features as the irrigation emitter.20. The emitter of any of examples 1 to 19, wherein a style of the one or more channels comprise one or more of a ramp-style, a branching-style, or a trapezoidal style.21. The emitter of any of examples 1 to 20, further comprising an inlet.22. A method of controlling flow during irrigation, comprising: flowing a fluid into a body of an emitter, the body having a volume that is defined between a pair of opposed walls, a pair of opposed sidewalls, and a top wall having a proximal-facing surface that is opposed to a bottom wall having a distal-facing surface, wherein the fluid: passes onto a diaphragm disposed in the body to deflect the diaphragm into a diaphragm pocket recessed into the proximal-facing surface; enters a labyrinth having a length that is no greater than about 9.5504 millimeters that is in fluid communication with the diaphragm pocket to flow through a plurality of recessed channels within the proximal-facing surface without significantly reducing a flow rate for one of fluid particles sized up to about 400 microns for a non- pressure-compensating (NPC) emitter or fluid particles sized up to about 120 microns for a pressure-compensating (PC) emitter; exits the labyrinth into a diaphragm cavity disposed below the diaphragm; and flows through a channel out of the body.23. The method of example 22, further comprising adjusting the flow rate of the emitter without changing activation pressure by changing a height of a lands surface, a geometry of the channel, and dimensions of the labyrinth simultaneously.24. The method of example 22 or example 23, further comprising increasing a hydraulic resistance of the one or more channels linearly with pressure above the activation pressure to set a constant flow rate.25. The method of any of examples 22 to 24, further comprising positioning a device within one or more tubes of an irrigation system such that it is in-line with a flow of fluid that passes through the one or more tubes.26. The method of any of examples 22 to 25, wherein positioning the device further comprises thermally bonding the device to an inner wall of a drip line of the one or more tubes.27. The method of any of examples 22 to 26, wherein positioning the device further comprises molding and inserting the device into the one or more tubes at set spacings.28. The method of any of examples 22 to 27, wherein the fluid passes onto the diaphragm until the diaphragm contacts a lands disposed in the diaphragm pocket that extends proximally from the distal-facing surface.29. The method of any of examples 22 to 28, wherein the channel comprises one or more of a variable depth channel, a branching channel, or a trapezoidal channel.30. The method of example 29, wherein a flow rate through the channel with the trapezoidal cross-section is substantially constant between about 0.9 L / hr to about 1.25 L / hr at pressures above 5 psi.31. The method of example 29 or example 30, wherein the trapezoidal cross-section has a height (hchan) of up to about 0.010 inches and a width (wchan) of up to about 0.025 inches.32. The method of any of examples 21 to 31, wherein the fluid flows through a cover having tapering oblong extrusions that make an angle approximately between about 35 degrees to about 55 degrees with the incoming flow into a tube in which the body of the emitter is disposed to create a hydrodynamic boundary layer that prevents particulate entry into an inlet of the cover and speeds up smaller particles passing between them to prevent entry into the body of the emitter.33. An irrigation emitter, comprising: a body having a volume defined between a pair of opposed walls, a pair of opposed sidewalls, and a top wall having a proximal-facing surface that is opposed to a bottom wall having a distal-facing surface, the body including: a labyrinth forming a plurality of recessed channels within the proximal-facing surface, wherein the emitter has an activation pressure that can be as low as 0.3 bar, a length that is no greater than 0.85 inches, and is configured to flow a particle sized up to about 400microns without a significant reduction in flow rate for a non-pressure-compensating (NPC) emitter.34. The emitter of example 33, wherein a flow rate through the NPC emitter can range between about 1.02 to about 3.8 liters / hour at 1 bar.35. A hydraulic system comprising: a. a pump configured to produce water using hydraulic pressure; b. an drip emitter of example 1 ; and c. a tube for connecting the pump to a multiplicity of drip emitters.

[0087] One skilled in the art will appreciate further features and advantages of the disclosures based on the provided for descriptions and embodiments. Accordingly, the inventions are not to be limited by what has been particularly shown and described. To the extent the present disclosure includes illustrations and descriptions that include prototypes, bench models, or schematic illustrations of set-ups, a person skilled in the art will recognize how to rely upon the present disclosure to integrate the techniques, systems, devices, and methods provided into a product and / or method of irrigating, such as drip emitters. Further a person skilled in the art will appreciate how to manufacture emitters like those provided for herein using production methods such as milling of a homogenous material (e.g. aluminum or a plastic) via a milling machine.

[0088] Some non-limiting claims that are supported by the contents of the present disclosure are provided below.

Claims

What is claimed is:

1. An irrigation emitter, comprising: a body having a volume defined between a pair of opposed walls, a pair of opposed sidewalls, and a top wall having a proximal-facing surface that is opposed to a bottom wall having a distal-facing surface, the body including: a diaphragm pocket recessed into the proximal-facing surface; a lands disposed within the diaphragm pocket that protrudes proximally from a bottom surface of the diaphragm pocket; one or more channels formed in the lands; and a labyrinth in fluid communication with the diaphragm pocket, the labyrinth forming a plurality of recessed channels within the proximal-facing surface, wherein the emitter has an activation pressure that can be as low as 0.3 bar, a length of the labyrinth that is no greater than 0.4 inches, and is configured to flow one of a particle sized up to about 120 microns without a significant reduction in flow rate for a pressurecompensating (PC) emitter or a particle sized up to about 400 microns without a significant reduction in flow rate for a non-pressure-compensating (NPC) emitter.

2. The emitter of claim 1, wherein a hydraulic resistance of the one or more channels increases linearly with pressure above the activation pressure to ensure a constant flow rate.

3. The emitter of claim 1, wherein a flow cross-section of the labyrinth is approximately in a range of about 0.5 mm to about 1 mm deep and approximately in a range of about 0.59 mm to about 0.67 mm wide, with at least six pairs of teeth being formed on a leg of the labyrinth.

4. The emitter of claim 1, further comprising a diaphragm disposed on a shelf formed within the diaphragm pocket.

5. The emitter of claim 1, wherein a width of the labyrinth does not exceed about 0.3 inches.

6. The emitter of claim 1, wherein the one or more channels comprises one or more of a variable depth channel, a branching channel, or a channel with a trapezoidal cross-section.

7. The emitter of claim 6, wherein a flow rate through the channel with the trapezoidal cross-section is substantially constant between about 0.9 L / hr to about 1.25 L / hr at pressures above 5 psi.

8. The emitter of claim 6, wherein the trapezoidal cross-section has a height (hchan) of up to about 0.010 inches and a width (wChan) of up to about 0.025 inches.

9. The emitter of claim 6, wherein a flow rate through a cross-section of the variable depth channel having a radially outward slope is approximately in a range from about 1 degree to about 2 degrees.

10. The emitter of claim 6, wherein a flow rate through a cross-section of the variable depth channel is substantially constant between about 0.8 L / hr to about 1.4 L / hr at pressures between about 5 to about 50 psi.

11. The emitter of claim 1 , wherein the emitter body receives the fluid from an irrigation system.

12. The emitter of claim 1, further comprising an inlet.

13. A method of controlling flow during irrigation, comprising: flowing a fluid into a body of an emitter, the body having a volume that is defined between a pair of opposed walls, a pair of opposed sidewalls, and a top wall having a proximal-facing surface that is opposed to a bottom wall having a distal-facing surface, wherein the fluid: passes onto a diaphragm disposed in the body to deflect the diaphragm into a diaphragm pocket recessed into the proximal-facing surface; enters a labyrinth having a length that is no greater than about 9.5504 millimeters that is in fluid communication with the diaphragm pocket to flow through a plurality of recessed channels within the proximal-facing surface without significantly reducing a flow rate for one of fluid particles sized up to about 400 microns for a non- pressure-compensating (NPC) emitter or fluid particles sized up to about 120 microns for a pressure-compensating (PC) emitter; exits the labyrinth into a diaphragm cavity disposed below the diaphragm; and flows through a channel out of the body.

14. The method of claim 14, further comprising adjusting the flow rate of the emitter without changing activation pressure by changing a height of a lands surface, a geometry of the channel, and dimensions of the labyrinth simultaneously.

15. The method of claim 14, further comprising increasing a hydraulic resistance of the one or more channels linearly with pressure above the activation pressure to set a constant flow rate.

16. The method of claim 14, further comprising positioning a device within one or more tubes of an irrigation system such that it is in-line with a flow of fluid that passes through the one or more tubes.

17. The method of claim 14, wherein the fluid passes onto the diaphragm until the diaphragm contacts a lands disposed in the diaphragm pocket that extends proximally from the distal-facing surface.

18. The method of claim 14, wherein the channel comprises one or more of a variable depth channel, a branching channel, or a trapezoidal channel.

19. The method of claim 14, wherein the fluid flows through a cover having tapering oblong extrusions that make an angle approximately between about 35 degrees to about 55 degrees with the incoming flow into a tube in which the body of the emitter is disposed to create a hydrodynamic boundary layer that prevents particulate entry into an inlet of the cover and speeds up smaller particles passing between them to prevent entry into the body of the emitter.

20. A hydraulic system comprising: a. a pump configured to produce water using hydraulic pressure; b. an drip emitter of claim 1 ; and c. a tube for connecting the pump to a multiplicity of drip emitters.

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