Irrigation device and method

Description

CROSS-REFERENCE

The present application claims priority from U.S. Provisional Patent Application No. 60/808,782 filed May 25, 2006, the contents of which are hereby incorporated in their entirety by reference, and which is not admitted to be prior art by its mention in the background.

FIELD OF THE INVENTION

The invention relates to an apparatus and method for injecting a fluid into soil, and more particularly to a device and method for use in the subsurface irrigation of plant roots.

BACKGROUND OF THE INVENTION

Subsurface irrigation of plant roots is well-known to reduce surface evaporation and to be useful for efficiently providing water, fertilizer, and other beneficial chemicals directly to the roots of plants with low losses, good control, reduced runoff, and reduced costs.

A number of devices for subsurface irrigation are known. U.S. Pat. No. 749,758 to Templeton discloses a device with a single nozzle or cutting teeth to aid in soil penetration; U.S. Pat. No. 1,937,172 to Starner et al. discloses a device with a sharp, wedge-shaped tip, the twisting of which aids in soil penetration; U.S. Pat. No. 2,333,727 to Lucas discloses an tip for soil penetration comprising a relatively sharp prong that aids in penetrating the soil ahead of the irrigating openings in the tube; U.S. Pat. No. 4,170,948 to Strickland discloses a device having a tapered single nozzle which is inserted into soil with the aid of a vibrating device attached to the pipe and powered by the water flow; and U.S. Pat. No. 4,697,952 to Maddock teaches the drilling of an irrigation hole using a down tube with a single outlet at its tip.

These approaches suffer from the drawback that the soil penetration of these devices attributable to the action of water flow upon the soil is relatively inefficient, requiring either a sharp tip or other additional means such as a vibrating device or cutting teeth to aid in penetrating the soil. However, sharp tips or cutting teeth readily damage plant roots thereby promoting disease, and damage buried structures such as cables. The need for additional devices such as vibrating devices is cumbersome, expensive and renders such devices unattractive for domestic use. Inefficient soil penetration also means that the tubes of these devices should be strongly constructed in order to withstand the greater forces that must be applied to them, thereby increasing weight and expense.

Notwithstanding the existence of a variety of subsurface irrigation devices in the prior art, there is a continuing need for more efficient and lightweight devices better adapted to domestic use and more enjoyable to use, and the present invention substantially fulfills these needs. All this and more will become apparent to one of ordinary skill upon reading the disclosure, drawings, statements, and claims appended hereto.

SUMMARY OF THE INVENTION

The present invention is directed to device and method for subsurface irrigation of soil and plant roots. In particular, the invention provides an irrigation device capable of insertion into soil to any desired irrigation depth with a minimum of effort, in which insertion is substantially aided by the flow of irrigation fluid dispensed from a novel and improved nozzle.

In a first embodiment, an irrigation device according to the present invention comprises a rigid tube comprising, at its proximal end, a means, such as a threaded fitting or compression fitting, for attaching to a source of pressurized fluid, for example a source of irrigation water from a mains supply, or a source that is pumped from portable container or from a large container attached to a vehicle. The distal end of the tube comprises a tip that seals said end but for a plurality of orifices disposed through the tip that permit the pressurized fluid in the tube to flow from said end at one or more acute angles relative to the major longitudinal axis of the tube. The device further comprises a means to regulate the flow of fluid within the tube, such as a ball valve or other suitable valve.

To minimize damage to plant roots or other sensitive buried structures such as buried cables or the like, the tip is substantially blunt, for example having a convex or hemispherical or other non-sharp outer surface.

The orifices are positioned to release more than one stream of the pressurized fluid. In particular, improved soil penetration is obtained from a device in which the openings are positioned to produce streams at one or more acute angles with respect to the major longitudinal axis of the pipe. Without thereby being limited by theory, it is believed that turbulence caused by the plurality of streams aids in the soil penetrating characteristics of the device compared to prior art devices.

In use, the steps of the method of the present invention can be performed in orders other than the order set forth below. The method comprises attaching a source of pressurized fluid to the attachment means of a device according to the present invention, for example by threadingly engaging a hose-pipe to a receptacle at the proximal end of the device; adjusting the valve means to provide streams of pressurized liquid from the tip; contacting the soil with the distal end of the device with downward pressure, such as for example gentle hand pressure; permitting the device to penetrate the soil to the desired, predetermined irrigation depth; and adjusting the valve means to provide a predetermined flow of fluid for a predetermined time in order to accomplish subsurface irrigation. For example, a high rate of irrigation can be obtained by adjusting the valve means to the point that irrigation fluid ceases to backflow to the surface.

It should be understood that an advantage of the present device is that the degree of downward pressure required to penetrate the soil is lessened by the soil displacing properties of the tip. The turbulent flow of pressurized irrigation fluid efficiently loosens and displaces the soil from the path of the tip, thereby reducing the required downward pressure. Further, visual cues such as irrigation fluid subsequently emerging at the soil surface can optionally be used to indicate the completion of irrigation.

It is therefore an object of the present invention to provide a device and method for subsurface irrigation of plant roots such as tree roots in which damage to the roots or other sensitive subsurface structures is minimized.

It is a further object of the present invention to provide a device capable of insertion to any desired irrigation depth with minimal physical effort and without the need for prior drilling of irrigation holes or the prior placement of permanent irrigation lines.

It is a further object to provide a subsurface irrigation device in which soil penetration is substantially aided by provision of a novel tip capable of producing multiple streams of fluid at one or more acute angles with respect to the major longitudinal axis of the tube, whereby a turbulent flow is produced upon contact with the soil and efficient soil penetration is obtained.

It is yet a further object to provide an efficient subsurface irrigation device that can be used to introduce fertilizer, pesticide, herbicide, or the like, at desired subsurface locations without loss of material or pollution due to surface application and runoff.

Thus, in a second embodiment, the irrigation device according to the present invention further comprises a reservoir for holding a pesticide, herbicide, insecticide, or the like, the reservoir being in fluid communication with the interior of the tube, either directly or via a second valve means, and whereby the reservoir fluid is drawn into and mixed with the irrigation fluid during operation of the device.

In a third embodiment, the tube of an irrigation device according to the present invention further comprises a detachable coupling whereby the length of the tube can be adjusted by inserting or removing tube sections of selectable length to adjust that length of the device in order to adjust the depth of irrigation.

In a fourth embodiment, markings are provided on the exterior of the device to facilitate irrigation at a reproducible desired depth.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:

FIG. 1 shows a perspective view of an embodiment of a subsurface irrigation device according to the present invention.

FIG. 2 shows a perspective view of an alternative embodiment of the subsurface irrigation device according to the present invention further comprising a reservoir for fertilizer, pesticide, herbicide, or the like.

FIG. 3 shows selected views of the tip of an embodiment of the subsurface irrigation device according to the present invention. A: longitudinal perspective view; B: longitudinal cross-sectional view; and C: end perspective view.

FIG. 4 shows a view of a subsurface irrigation device according to the present invention in use.

DETAILED DESCRIPTION

Certain exemplary but non-limiting embodiments of the present invention are now described with reference to the attached drawings.

Referring now to FIG. 1, an irrigation device 100 according to the present invention is shown. The device 100 comprises rigid tube 110. Tube 110 comprises a proximal end 120 comprising attachment means 130 for connecting the interior of the tube 110 to a source of pressurized liquid, and a distal end 140 comprising a tip 145 having plurality of openings 150 that are further described with reference to FIG. 3. Tube 110 can be constructed from any water-impermeable material of sufficient rigidity, strength and durability. The cross-sectional shape of tube 110 is preferable circular, but other cross-sections can also be used. Thus, as used herein, the term “tube” encompasses, for example and without limitation, oval, square, and triangular cross sections. In preferred embodiments, the tube is constructed from PVC, but other plastics, metals, fiber glass, and the like, can be used. The length of tube 110 in preferred embodiments is from about 15″ to about 60″. The tube can be of unitary construction, or can be constructed by assembling discrete parts as shown in the embodiment of FIG. 1.

The improved soil penetrating properties of the present device means that lighter and less stiff materials can be used for the tube because the device can be inserted into soil without undue force. Thus, as used herein, the term “rigid” refers to a self-supporting structure of sufficient rigidity for use according to the methods herein. For example, it is not required that the tube be sufficiently rigid as not to deform in use. Standard PVC pipe, such as 0.5 inch i.d. PVC pipe, can be used to form the pipe of a device of the present invention and is considered herein a “rigid tube” although it may deform to some extent in use.

Means 130 for attaching the proximal end of the tube to a source of pressurized liquid are well-known in the art and can include, for example, a threaded fitting, a snap-connector, a bayonet fitting, a shrink fit, or simply the insertion of the proximal end of the device into a hose with or without a securing clip surrounding the hose. By such means, a substantially leak-free connection can be formed whereby the source of pressurized liquid and the interior of tube 110 are placed in fluid communication. For ease of handling, and to avoid bending and crimping an attached hose, the pipe 110 optionally comprises a bend 160, such as a perpendicular bend, towards the proximal end 120. Notwithstanding bend 160, pipe 110 comprises a major longitudinal axis 180, to which the directions of the streams of pressurized fluid emitted by the tip 145 are referenced.

A valve means 170 is provided to regulate and control the flow of liquid within tube 110. In the embodiment of FIG. 1, a ball valve is shown, but a variety of suitable valves are well known to those of skill in the plumbing and irrigation arts. Preferably, valves capable of incremental regulation of the flow are used. For example, the valve means 170 can be operated by a rotating handle or can be coupled to a trigger-type actuator, whereby the flow is controlled by the degree of rotation of the handle, or the pressure applied to the trigger-type actuator, respectively. The valve can be manually operated or can, for example, be remotely operated using a solenoid valve. The position of the valve along the tube is not particularly limited, and is preferably positioned between bend 160 and attachment means 130.

Optionally, tube 110 can further comprise a means for adjusting the length of the tube, such as for example detachable coupling 190 for reversibly inserting an extension tube. A selection of insertable pipe portions can be provided having differing lengths and/or diameters, according to the depth of irrigation desired, the condition or composition of the soil, or other factors, and the selected portion(s) can used to extend tube 110 by means of their insertion and attachment at the detachable coupling.

To aid in locating the desired depth of irrigation, the outer surface of the tube can optionally further comprise depth markings 195 such as, for example, one-inch markings measured from openings 150.

Referring now to FIG. 2, a second exemplary irrigation device 200 according to the present invention is shown further comprising a reservoir 210 for fertilizer, pesticide, herbicide, or the like. The reservoir 210 can be in the form of a plastic bottle or other suitably shaped and constructed container, and can be clear or opaque. Optionally, reservoir 210 is affixed to the tube by any suitable attachment means, such as by straps 220, or by clamps, screws, bolts, or the like, or by unitary molding of the reservoir 210 and the tube. Alternatively, the reservoir 210 is not mounted to the tube and can be a reservoir such as a free-standing tank or a large tank mounted to a vehicle.

Reservoir 210 is fluidly connected to the interior of the tube, for example by pipe 230 at attachment point 240. Without being limited by theory, in use the flow of fluid in tube 110 generates a reduced pressure or siphoning effect that draws liquid from reservoir 210, which thereby become diluted and mixed to form the irrigating fluid. Alternatively and optionally, the liquid can be pumped or metered from a reservoir into the tube, and a second valve 250 can be interposed between the reservoir 210 and the tube 110.

Referring now to FIG. 3, there are shown selected views 300 of the tip 310 of an embodiment of the subsurface irrigation device according to the present invention.

The longitudinal perspective view in FIG. 3A illustrates substantially blunt tip 310. The blunt tip preferably comprises a convex outer surface. Most preferably the outer surface of the tip is hemispherical. The substantially blunt tip is advantageous in avoiding damage to plant roots or other buried structures such as cables and the like. Disposed within and through tip 310 is a plurality of openings or orifices 320 fluidly connecting the interior and exterior of the tip.

As shown in longitudinal cross-sectional view in FIG. 3B, the orifices are disposed and oriented to produce, in use, a plurality of streams of liquid at one or more acute angles 330, 340 in a plurality of directions 360, 370, 380, with respect to longitudinal axis 350 of the tube. Optionally, one of the openings 390 produces a stream of liquid coincident with longitudinal axis 350. Other numbers and orientations of orifices can be used within the scope of the present invention. For example, the orifices can be arranged to produce a helical flow pattern by offsetting the centerline of one or more orifices with respect to longitudinal axis 350 of the tube. The term “acute” as used herein with respect to both helical, non-helical, or other flow patterns, refers to the condition that the angle subtended by the direction of a stream produced by an orifice and any plane containing the longitudinal axis 350 of the tube is less than 90 degrees. Preferably the acute angles 330, 340 are from about 0 to about 45 degrees, and most preferable from about 0 to about 25 degrees. Preferably, the tip comprises from 2 to about 20 orifices.

The plurality of orifices as described herein produces a turbulent flow when placed in contact with the soil, which improves ground penetration.

Operation and use of a subsurface irrigation device according to the present invention is shown in FIG. 4. If the device is to be used to irrigate the roots of a plant 420, the proximal end of the device is attached to a source of pressurized fluid 440 such as water, the second end of the device is placed upon the surface of the soil 430 and the operator exerts a moderate downward pressure on the device. Because of the turbulent flow emitted from the tip, the device readily penetrates soil to a predetermined irrigation depth. The downward pressure is then be removed, and the flow adjusted using the valve means to deliver a predetermined irrigation flow-rate for a predetermined time. It will be appreciated that the device can readily be moved from one irrigation position to another with a minimum of time, effort and wasted fluid.

The device of the present invention provides a number of advantages over the prior art. The enhanced soil penetrating properties of the device mean that the device can be constructed of lighter materials and is thereby more portable and easier to use. The ability to easily move the device to irrigate at different subsurface locations means that irrigating liquid is more efficiently applied, with less waste, and surface losses due to evaporation are minimized. Polluting runoff of gardening chemicals is also reduced. These advantages therefore provide benefits to the plants, the user, and the community.

Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible and can be envisaged within the scope and spirit of the present invention. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.

Now that the invention has been described: