Patent Application
20090188991
1. Field of the Invention
The present invention relates to irrigation nozzles or sprinkler heads, as used in automatic lawn sprinkling and other irrigation systems.
2. Discussion of Related Art
In-ground irrigation nozzles (e.g., sprinkler heads) have been on the market for many years and come in many different configurations for depositing a selected amount of irrigation fluid (e.g., water) upon a designated landscape area through a spray. For a good performing spray, the amount of water sprayed is minimized to: (a) reduce runoff, yet (b) still adequately irrigate the entire area and (c) do so in a reasonable amount of time. The amount of water used is defined as “precipitation rate” (or “PR”) commonly measured and expressed in “inches per hour” or “in/hr.”
Uniform distribution is desirable and the uniformity in distribution of that water is commonly measured and expressed in terms of the Scheduling Coefficient (“SC”), which can be used as a multiplier to determine how much longer a spray must run in order to irrigate the driest patch to the same amount as the mean application rate for the entire area. Optimum precipitation rates depend on soil conditions, but in general it is desirable to have an irrigation nozzle assembly (or sprinkler) with a PR of 1 in/hr or less. SC values of 1.5 or less are considered good within the irrigation industry, with an absolute best being 1.0.
In order to achieve good spray performance, some nozzles on the market today utilize rotating parts, friction plates, and viscous brakes. U.S. Pat. No. 6,942,164, to Walker is a useful example of a rotating sprinkler or nozzle. While these rotator nozzles can achieve a PR around 0.5 in/hr and good distribution, they are relatively costly compared to fixed sprays. Current sprinkler heads with fixed sprays have no moving parts and are used in short to medium spray throw distances (up to 15 feet or so), but have PR's greater than 1 in/hr and varying spray distribution, including dual spray designs.
Current fixed sprays are “non-fluidic” and so rely on spreading an impinging jet into a fan spray (i.e., a liquid sheet). This shears the spray and so can make finer drops having lower velocity. As a result, these nozzles have high PR (about 1.4 and above), especially at longer throws (throw is also referred to as radius, in some applications). For a 360 deg spray (i.e., a full spray), non fluidic nozzles typically use a swirl spray that produces a conical sheet. Swirling sheets also produce fine drops and low velocity, resulting in a low throw (or short radius).
Fixed sprays are available in throws (or radii) ranging from 5′ to 15′ with a 25% throw adjustment for each nozzle. Achieving throws from 5′ to 10′ at low PR (PR≦1) is relatively easy even for non fluidic sprays. However as the throw increases (i.e. for 12′ and 15′), velocity and droplet size become critical, and PR increases (PR>1.4) for non-fluidic sprays.
Applicants have discovered that fluidic spray nozzles may be designed for a wide range of PR values, and particularly PR≦1 all through the range of 5′-15′, but these results required a significant amount of new development work, experimentation and testing.
Generally speaking, fluidic oscillators are known in the prior art for their ability to provide a wide range of liquid spray patterns by cyclically deflecting a liquid jet. Examples of fluidic oscillators may be found in many patents, including U.S. Pat. Nos. 3,185,166 (Horton & Bowles), 3,563,462 (Bauer), 4,052,002 (Stouffer & Bray), 4,151,955 (Stouffer), 4,157,161 (Bauer), 4,231,519 (Stouffer), which was reissued as RE 33,158, 4,508,267 (Stouffer), 5,035,361 (Stouffer), 5,213,269 (Srinath), 5,971,301 (Stouffer), 6,186,409 (Srinath) and 6,253,782 (Raghu), which are summarized below.
The operation of most fluidic oscillators is usually characterized by the cyclic deflection of a fluid jet without the use of mechanical moving parts. Consequently, an advantage of fluidic oscillators is that they are not subject to the wear and tear which adversely affects the reliability and operation of pneumatic oscillators and reciprocating nozzles. The fluidic oscillators described in U.S. Pat. No. 3,185,166 (Horton & Bowles) are characterized by the use of boundary layer attachment (i.e., the “Coanda effect,” so named for Henri Coanda, the first to explain the tendency for a jet issuing from an orifice to deflect from its normal path (so as to attach to a nearby sidewall) and the use of downstream feedback passages which serve to cause the jet issuing from a power nozzle to oscillate between right and left side exit ports.
At the risk of boring those having skill in this rather specialized art, a rather substantive background is provided here. It is understood that the three-dimensional character of the flow from such fluidics can take a variety of forms depending upon the three-dimensional shape of the fluidic. For example, oscillators described in U.S. Pat. No. 4,052,002 (Stouffer & Bray) are characterized by the selection of the dimensions of the fluidic such that no ambient fluid or primary jet fluid is ingested back into the fluidic's interaction region, which yields a relatively uniform spray pattern made up of droplets of more uniform size. The absence of inflow or ingestion from outlet region is achieved by creating a static pressure at the upstream end of interaction region which is higher than the static pressure in outlet region. This pressure difference is created by a combination of factors, including: (a) the width T of the exhaust throat is only slightly wider than power nozzle so that the egressing power jet fully seals the interaction region from outlet region; and (b) the length D of the interaction region from the power nozzle to throat, which length is significantly shorter than in prior ‘fluid ingesting’ oscillators. It should be noted that the width X of control passages is smaller than the power nozzle. If the width of power nozzle at its narrowest point is W, then the following relationships were found to be suitable, although not necessarily exclusive, for operation in the manner described: T=1.1-2.5 W and D=4-9 W, with the ratios of these dimensions also being found to control the fan angle over which the fluid is sprayed. By adding a divider in this fluidic's outlet region, it becomes what can be referred to as two-outlet oscillator of the type that might be used in a windshield washer system. See, for example, U.S. Pat. No. 4,157,161 to Bauer.
The fluidic oscillators described in U.S. Pat. No. 4,231,519 (Stouffer, reissued as U.S. Pat. No. RE 33,158), are also unique in that they employ yet another fluid flow phenomena to yield an oscillating fluid output. The oscillators of U.S. Pat. No. 4,231,519 are characterized by their utilization of the phenomena of vortex generation, within an expansion chamber prior to the fluidic's throat, as a means for dispersing fluid. It comprises a jet inlet that empties into an expansion chamber which has an outlet throat at its downstream end. It also has an interconnection passage that allows fluid to flow from one side to the other of the areas surrounding the jet's inlet into its expansion chamber. The general nature of the flow in such fluidics is that vortices are seen to be formed near the throat. As the vortices grow in size they cause the centerline of the fluid flowing through the expansion chamber to be deflected to one side or the other such that the fan angle of the jet issuing from the throat ranges from approximately +45 degrees to −45 degrees. The result of these flow oscillations is a complicated spray pattern, which at a given instant takes a sinusoidal form (similar to that shown in
The fluidic oscillators disclosed in U.S. Pat. Nos. 5,213,269 (Srinath) and 5,971,301 (Stouffer) are referred to as “box oscillators” having interconnects which serve to help control the oscillating dynamics of the flow that exits from the fluidic's throat. For example, the effect of these interconnects, assuming that they are appropriately dimensioned relative to the other geometry of the fluidic, is generally seen to be about a doubling of the fan angle of the fluid exiting from the fluidic's throat. FIG. 8(a) from U.S. Pat. No. 5,213,269 shows an embodiment in which the interconnect takes the form of passage that connects points on opposite side of the fluid's throat. FIG. 8(b) from U.S. Pat. No. 5,971,301 shows an embodiment in which the interconnect takes the form of a slot in the bottom wall of the fluidic's interaction region.
U.S. Pat. No. 6,253,782 (Raghu) discloses a fluidic oscillator of the type that provides a shaped interaction region having two entering power nozzles and a single throat through which the resulting fluid flow exits the fluidic oscillator. See
In order to function properly, fluidic oscillators need to have proper sealing so as to not cause leaking across flow channels. The typical construction for the fluidic oscillator has been to fabricate the fluidic circuit in one surface and sealed with another surface.
Irrigation nozzles such as lawn sprinklers, generally, and fluidic oscillators, generally, are distinct technologies and each are known to persons in their respective areas of the different arts, but there has not yet been a satisfactory way to combine them into a reliable and cost effective structure or method for generating adequately high velocity and large droplet size in a manner that would be advantageous for irrigation applications, where a long throw is desired with low flow rate, so that the “precipitation rate” can be reduced.
Fluidic sprays rely on a jet that oscillates to produce a fan spray. Thus, the output is not a liquid sheet but a stream that has high velocity with good droplet size. This knowledge has been applied to the long felt need to provide a reliable, inexpensive and uniform system and method for irrigating a selected region.
Other considerations have also been addressed. Sprinkler systems used for irrigating lawns and parks must be serviced periodically, to prevent damage from expansion of freezing water in the pipes and sprinkler heads. Annually, the systems are cleared of water, often with compressed air, to drive all water out of the pipes and sprinkler components. The following spring, water is re-introduced into the system and that water must first displace the air in the pipes.
Recent advances in fluidics technology have been evaluated for use in irrigation systems, partly because fluidic oscillators can be adapted to provide a very uniform pattern of fluid dispersion over an area selected for irrigation. These new fluidic circuits provide significantly different hydraulic impedance to the flow of water, when compared to an open spray nozzle, however, and so the introduction of water into a system having trapped air in the lines presents a new challenge.
Specifically, the applicants have discovered a problem with a fluidic equipped prototype sprinkler or nozzle assembly. The issue was that under some conditions, mainly after winterization of a residential or commercial irrigation system, there is an air void in the plumbing leading up to the fluidic equipped nozzle. When the water is turned back on to the system a wave of water travels at a high rate of speed down the plumbing, displacing the air. This instantaneous impact created by the density difference between the remaining air void and wave of water generates excessive loads that can damage a fluidic nozzle insert or force it out of the housing. The impact force produced by the “surge” turns out to be quite high, close to 30 lbf.
There is a need, therefore, for a convenient, reliable and inexpensive assembly structure and method for protecting a fluidic equipped irrigation nozzle from the water-hammer like effect of this first inrush of water.
The nozzle assemblies and method of present invention overcome the above mentioned difficulties by providing a reliable and inexpensive system and method for irrigating a selected area. By combining selected lawn sprinkler technologies with newly configured fluidic oscillators, the problems discussed above are overcome. A reliable and cost effective structure and method are shown to generate adequately large, high Velocity droplets for irrigation applications, where a long throw is desired with low flow rate, so that the “precipitation rate” can be reduced.
In accordance with the present invention, a sprinkler head or irrigation nozzle achieves long throw distance using a “fixed” assembly with no oscillating or rotating parts. In order to throw long distance, velocity and droplet size are very important in addition to the initial aim angle. The applicants have discovered that velocity plays a stronger role than droplet size to determine the throw. These discoveries enable the development of a nozzle that can provide low PR for fluidic sprays.
The present invention effectively utilizes fluidic technology to achieve good spray performance, obtaining a PR of 1 in/hr or less and good spray distribution with a SC of about 1.5 without utilizing any moving components and which is significantly more cost effective than rotator nozzles.
The fluidic irrigation nozzle (or sprinkler head) assembly of the present invention includes a cylindrical housing having an exterior sidewall with one or more slots in which spray generating fluidic inserts or plugs are inserted. Depending on the spray configuration desired, the appropriate number of inserts (or fluidic circuit chips) are assembled, with the remaining slots filled with blanks. The inserts seal against the housing so that irrigation fluid (e.g., water) is emitted or exits only through insert throat openings.
In an alternative embodiment, the fluidic oscillators are permanently bonded within the slots, or are integral with the housing's exterior surface.
The top of the housing preferably has markings to indicate the nominal throw radius and the spray arc for the appropriate spray configuration. A radius adjustment screw is threaded through the housing and accessed by the installer or user from above with a simple flat-bladed screwdriver. The radius adjustment screw is used to change the amount of irrigation fluid flow that enters the insert(s) and therefore affects the throw radius of the emitted spray.
The exemplary nozzle assemblies of the present invention are described in greater detail below, but each is configured with a housing that will work in standard sprinkler systems, in place of standard fixed or pop-up sprinkler heads. In the illustrated embodiments, the housing has a substantially cylindrical exterior sidewall with an outside diameter of 19.18 mm, an axial length of 11.18 mm, terminates distally in an transverse flange having an outside diameter of 22.86 mm and carries, on its proximal end, a narrower threaded proximal tubular segment with an outside diameter of 15.01 mm. While the illustrated embodiments are “male” meaning that the proximal segment carries external threads (e.g., ⅝-28), the nozzle assemblies are also readily configured as “female” meaning that the connecting threads are carried within the proximal tubular segment's interior sidewall, near the proximal end.
Obtaining the improved performance of the present nozzle assembly is not a matter of simply grafting a fluidic circuit into the sidewall of a sprinkler nozzle, however, because new problems were encountered. Sprinkler systems used for irrigating lawns and parks must be serviced periodically, to prevent damage from expansion of freezing water in the pipes and sprinkler heads. Annually, sprinkler systems are cleared of water, often with compressed air, to drive all water out of the pipes and sprinkler components. The following spring, water is re-introduced into the system and that water must initially displace the air in the pipes.
The prototype fluidic oscillators which have been be adapted to provide a very uniform pattern of fluid dispersion over an area selected for irrigation provide significantly different hydraulic impedance to the flow of water, when compared to an open spray nozzle. And so the introduction of water into a system having trapped air in the lines presented a new challenge. Specifically, the applicants have discovered a problem with a fluidic equipped sprinkler or nozzle assembly. In a new installation or after winterization of a residential or commercial irrigation system, the air void in the plumbing leading up to the fluidic equipped nozzle gives way to inrushing water, which has considerable mass. When the water is turned on, a wave of water travels at a high rate of speed down the plumbing, displacing the air, which hisses out through the relatively tiny fluidic circuit orifices, until the inrushing water crashes into the fluidic circuit's inlets. An instantaneous impact is created by the density difference between the remaining air being voided and wave of water and that impact generates excessive loads that can damage a fluidic nozzle insert or force it out of the housing. The impact force produced by the “surge” turns out to be quite high, close to thirty pounds-force (“30 lbf”).
The structure and method of an illustrative embodiment of the present invention protects a fluidic equipped irrigation nozzle from the water-hammer like effect of this first inrush of water. In one embodiment, a ring-shaped Pressure Compensating Device (“PCD”) holder is dimensioned to be press-fit onto the bottom of the housing. The PCD holder or ring acts as a restrictor and shutoff for the radius adjustment screw. The PCD holder also seals against a filter basket, which provides a sieve or screen and prevents debris larger than a certain size from entering the insert(s) and clogging them, and can serve to hold a PCD gasket, an optional item that can be used to help stabilize flow under varying supply pressure.
In an alternative embodiment, a filter basket snaps into the housing and provides a valve seat surface for the radius adjustment screw's proximal end. The spray performance is relatively stable under various pressures, due to the fluidic oscillator(s).
A basic fluidic irrigation nozzle or sprinkler head in accordance with the present invention can have a variety of spray patterns. Fixed sprays are available as Q (90 deg), H (180 deg), TQ (270 deg), F (360 deg), T (120 deg), TT (240 deg), as well as 60 deg, 150 deg and 210 deg sprays and as specialty sprays. In the elementary form, a selected fluidic insert such as a Three Jet Island or a Mushroom has been used to produce a 90 deg fan. This could be a single spray or a double spray, having a fluidic geometry on both sides of an insert. In the elementary form, the fluidic irrigation nozzle is quite satisfactory, however there were some issues with radius control and low PR. In order to optimize the spray (i.e. achieve PR<1 and SC ˜1.5), a preferred fluidic embodiment utilizes a split throat mushroom on one side and a single mushroom circuit on the other. This combination yields PR<=1, SC<=1.5 and, when combined with the filter interface and radius adjustment screw, robust radius control.
One embodiment for the fluidic has been adapted for enhanced uniformity over a selected spray area, and includes “bumps” which are dimensioned and positioned to optimize the oscillating pattern for use in some applications. The “bump” embodiment fluidic circuit and method can redistribute bands of heavy flow, resulting in a more uniform flow distribution while using no power or moving parts. In the exemplary embodiment, a bump or upwardly projecting protrusion is added to the floor of the circuit downstream of the throat, near the heavy portion of the spray. The exemplary protrusion is cylindrical in shape, but other shapes may be used. The protrusion does not take up the entire the height of the circuit. The fluidic circuit sweeps a stream of fluid back and forth across the opening. As the heavy stream passes over the protrusion, the flow is diverted over and around the protrusion, and broken into smaller drops. When the stream continues on to the other extreme of its travel, it is not affected by the protrusion. In a case where it is desirable to smooth the heavy center of a fluidic's spray without affecting the crisp edges of the spray, the protrusions are located closer to the splitter than to the outer edge of the spray. There are options for breaking up the heavy ends of a fluidic's spray. One large bump or protrusion can be used, centered within the sweep of the oscillating stream, or two substantially symmetrically arrayed equal-size protrusions may be used, closer to the edges of the spray. For a wider fan, using two protrusions will be more effective in redistributing the heavy ends. However, two separate bumps may not fit under a narrower fan, in which case, a single protrusion may be used. As noted before, the protrusions need not be circular in cross-section; a racetrack-shaped protrusion is another option.
The effect of these protrusions makes the spray from a circuit more uniform, because heavy spikes in the spray pattern are suppressed and the spray's uniformity over a selected azimuth or angular spray region is improved. Larger protrusions will have more of an effect on the spray. Applicants have been successful with protrusions 5-15% the height of the circuit, and more recently, with protrusions 5-40% the height of the circuit. The diameter of the protrusions (e.g., 0.3 mm) can vary from a fraction of the throat width to the same order of magnitude as the throat width.
The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of a specific embodiment thereof, particularly when taken in conjunction with the accompanying drawings, wherein like reference numerals in the various figures are utilized to designate like components.
a is a top view of another fluidic circuit, illustrating diameter and lateral placement of a single upwardly projecting protrusion or “bump” feature at the outlet, to increase the uniformity of the spray emitted from the fluidic circuit, in accordance with the present invention.
b is a top view of yet another fluidic circuit, illustrating diameter and lateral placement of a first and second upwardly projecting protrusions or “bump” features at the outlet, to increase the uniformity of the spray emitted from the fluidic circuit, in accordance with the present invention.
Turning now to
Nozzle assembly 150, illustrated in
Nozzle assembly 150 can be configured to include one, two, three or four fluidic circuit inserts or chips 101 which are dimensioned to be tightly received in and held by the radially arrayed slots 110 defined within the sidewall of housing 103. The ports or slots 110 provide a channel for fluid communication between the housing's interior lumen and the exterior of the housing. Blanks or plugs 102 are also dimensioned to fit tightly within housing slots 110, and those slots fitted with a plug 102 are sealed and thus prevent any fluid passing between the housing's interior and the housing's exterior in the radial direction of the sealed slot. Housing 103 has a distal or top closed end with an annular distal flange and a dished or recessed circular end wall having a vertical and axially aligned, threaded bore that threadably receives an axially aligned adjustment screw 104. The distal end or top of adjustment screw 104 preferably includes a transverse slot sized to receive a slotted screw driver. Adjustment screw 104 has an elongate shaft with threads extending from the distal end to a central portion of the shaft and the proximal end or bottom of adjustment screw 104 includes a frustoconical head which defines a flow-restricting valve plug end.
Nozzle assembly 150 also includes a cylindrical collar or Pressure Compensating Device (“PCD”) holder which also defines a hollow interior lumen with an inwardly projecting annular flange that is contoured to provide a sealing surface which can act in cooperation with the flow restricting valve plug end at the proximal end of adjustment screw 104 to adjust the flow entering the lumen within housing 103. As can be seen by reference to the cross sectional view of
In order to throw droplets of irrigation fluid over a long distance, velocity and droplet size are very important, as is the initial aim angle. Applicants have discovered that velocity plays a stronger role than droplet size to determine the throw. This discovery enables a low PR through the proper configuration and use of fluidic sprays. Irrigation nozzle assembly 150 effectively utilizes fluidic technology to achieve good spray performance, obtaining a PR of 1 in/hr or less and good spray distribution with a SC of about 1.5 without utilizing any moving components. As a result lawn sprinkler using nozzle 150 is significantly more cost effective than prior art rotator nozzles.
Alternatively, using 10% greater flow yields a PR of 1.1 inch per hour with an SC in the range of 1 to 2, for various examples of the nozzle assembly.
The nozzle assembly is capable of providing a relatively constant precipitation rate (or Matched Precipitation Rate “MPR”) over a range of throw, radius (e.g., 5, 10 or 15 feet) or arc (e.g., 90, 120, 180 or 360 degree) conditions.
Referring again to
A basic fluidic irrigation nozzle in accordance with the present invention can have a variety of spray patterns. Fixed sprays are available as Q (meaning “quarter” for 90 deg), H (meaning “half” for 180 deg), TQ (meaning “three-quarter” for 270 deg), F (meaning “full” for 360 deg), T (meaning “third” for 120 deg), TT (meaning “two-thirds” for 240 deg) and as specialty sprays. In the elementary form, a selected fluidic insert such as a Three Jet Island (e.g., as shown in
The internal structures of the fluidic oscillators are further described in this applicant's other patents and pending applications. For example, the “Mushroom” oscillator as shown in
In the elementary form, the fluidic irrigation nozzle is quite satisfactory; however there were some issues with adjusting radius control while maintaining low PR. In order to optimize the spray (i.e. achieve PR<1 and SC ˜1.5), a fluidic circuit embodiment ‘A’ using a split throat mushroom on one side and a single mushroom circuit on the other was developed. This combination yields PR<1, SC of 1.5 and robust radius control. Nozzle assembly and fluidic circuit embodiments with this combination of fluidics are illustrated in
An alternative embodiment is illustrated in
Fluidic “chips” or inserts (e.g., A, B or C as shown in
The sprays also have a good distribution or SC. In the embodiment of
The fluidic circuit or insert 101 (or “A”) is a split throat mushroom on one side and a standard mushroom on the other side. The split throat mushroom produces a 90 deg fan and enables an increase in droplet velocity of 20% compared to a standard mushroom with 90 deg fan.
In the embodiments of
Returning to
The ‘top’ mushroom oscillator (diagrammed in
The ‘bottom’ mushroom oscillator (diagrammed in
Fluidic circuits (e.g., 101, 201, 301 or 401) are inserted in one, two, three or four slots (e.g., 110) in the housing (e.g., 103, 203 or 403) to produce fan angles from 90° (for using only one fluid for one quadrant) to 360° (using four fluidics to spray into all four quadrants). The remaining slots are filled with blanks (e.g., 102, 202 or 402). Other fan angle combinations can also be used.
Referring now to
Turning now to another embodiment shown in
Since the ‘top’ 3-jet island oscillator 301A produces a uniform 50° fan and the ‘bottom’ mushroom oscillator 301B produces a 90° fan with 20° heavy ended bands, an overlay of the two fans shows that the top and bottom fans, when superimposed, are complementary. The uniform 50° fan of the top spray fills the light center of the 90° fan of the bottom spray. Both sprays target the far field, while the smaller drops and lower velocity of the light center of the bottom spray contribute to the near field.
As before, the inserts, chips or circuits (e.g., 301) are inserted in one to four slots in the housing to produce fan angles from 90° to 360°. The remaining slots are filled with blanks 302. Other fan angle combinations can also be used.
Turning now to
As in the other embodiment described above, the interior sidewall surfaces of each port or slot 410 are preferably dimensioned for cost effective fabrication using molding methods and preferably include sidewall grooves positioned and dimensioned to form a “snap fit” with ridges or tabs in mating inserts (e.g., 401) or blanks (e.g., 402).
For nozzle assembly 450, the ‘top’ feedback oscillator produces a relatively uniform 90° fan that targets the far field (long range), and the ‘bottom’ feedback oscillator produces a relatively uniform 90° fan that targets the near field (short range). A kit can be configured with one to four inserts or chips 401 for insertion in one to four slots 410 in the housing to produce fan angles from 90° to 360°. The remaining slots, if any, are filled with blanks 402. Other fan angle combinations can also be used.
Testing of prototype fluidic irrigation assemblies such as those shown in
SC values are expected to improve further with added development and adjustment (e.g., should get better with center “bulge” brought in on fixed sprays, assuming same spray uniformity.
Special Considerations for Pressure Spikes in Sprinkler Assemblies:
As noted above, sprinkler systems used for irrigating lawns and parks must be serviced periodically, to prevent damage from expansion of freezing water in the pipes and sprinkler heads. Annually, the systems are cleared of water, often with compressed air, to drive all water out of the pipes and sprinkler components. The following spring, water is re-introduced into the system and that water must first displace the air in the pipes.
Recent advances in fluidics technology have been evaluated for use in irrigation systems, and these new fluidic circuits provide significantly different hydraulic impedance to the flow of water, when compared to an open spray nozzle, so the introduction of water into a system having trapped air in the lines presents a new challenge. Specifically, the applicants have discovered a problem with a fluidic equipped sprinkler or nozzle assembly. The issue was that under some conditions, mainly after winterization of a residential or commercial irrigation system, there is an air void in the plumbing leading up to the fluidic equipped nozzle. When the water is turned back on to the system, a wave of water travels at a high rate of speed down the plumbing, displacing the air. This instantaneous impact created by the density difference between the remaining air void and wave of water generates excessive loads that can damage a fluidic nozzle insert (e.g., 101) or force it out of the housing. The impact force produced by the “surge” turns out to be quite high, close to 30 lbf. This impact force is accommodated by use of a new fluidic insert retaining structure.
Referring now to FIGS. 2 and 19-22, sprinkler assembly 250 includes a sprinkler housing 203A including an interior lumen and an exterior sidewall, with at least one fluidic-circuit-receiving port or slot 210 carrying a fluidic insert 201 configured to receive irrigation fluid passing into the housing lumen and, in cooperation with the port or slot 210, passes irrigation fluid and projects the irrigation fluid in a desired spray pattern. Fluidic insert 201 is held precisely in place by a retention ring 205 (as shown in FIGS. 2,19 and 20 adapted for insertion into the housing's interior lumen to provide a snap or friction fit with the fluidic insert 201. Retention ring 205 fits into the pre-existing sprinkler housing or package, is preferably molded of plastic material and is made as a single component for economic purposes, and does not have any effect on external appearance or fluidic performance as other more traditional fasteners would.
In an alternative embodiment, the fluidic oscillators 201 are permanently bonded within the slots, or are integral with the housing's exterior surface.
As with the embodiments described above, nozzle assembly 250 is configured with a housing 203A that will work in standard sprinkler systems, with a substantially cylindrical exterior sidewall having an outside diameter of 19.18 mm, an axial length of 11.18 mm, which terminates distally in an transverse flange having an outside diameter of 22.86 mm and carries, on its proximal end, a narrower threaded proximal tubular segment with an outside diameter of 15.01 mm. While the illustrated embodiment is “male” meaning that the proximal segment carries external threads (e.g., ⅝-28), the nozzle assembly is also readily configured as “female” meaning that the connecting threads are carried within the proximal tubular segment's interior sidewall, near the proximal end holding snap-in filter segment 206.
One, two, three or four fluidic circuit inserts or chips 201 are dimensioned to be tightly received in and held by the radially arrayed slots 210 defined within the sidewall of housing 203A. The slots 210 provide a channel for fluid communication between the housing's interior lumen and the exterior of the housing. There are also between one and three plugs 202 which are also dimensioned to fit tightly within housing slots 210, and those slots fitted with a plug 202 are sealed and thus prevent any fluid passing between the housing's interior and the housing's exterior in the radial direction of the sealed slot. Housing 203A has a distal or top closed end with an annular distal flange and a dished or recessed circular end wall having a vertical and axially aligned, threaded bore that threadably receives axially aligned adjustment screw 204. The distal end or top of adjustment screw 204 preferably includes a transverse slot sized to receive a slotted screw driver. Adjustment screw 204 has an elongate shaft with threads extending from the distal end to a central portion of the shaft and the proximal end or bottom of adjustment screw 204 includes a frustoconical head which defines a flow-restricting valve plug end that can be sealed against the upper surface or interface of filter 206.
The control of fluid flow and the radius of the spray is provided by a flow conditioning proximal head of screw 204 which can be advanced to shut off fluid flow on the distal interface surface of filter 206. The shape of the head now preferred is illustrated in
Retention ring 205 can be customized to fit into other commercial sprinklers or Fluidic Nozzle housings. Sprinkler assembly 250 has the cylindrical interior lumen or passage and latching retention ring 250 is inserted into that lumen (pushed into the ID of the housing from underneath). Upon complete insertion, tab features 260 mate to a “tail” or latch interface 270 on fluidic insert 201 that has been installed in sprinkler assembly 250. The latch “tail” 270 on fluidic insert 201 allows fluidic inserts to be assembled normally into housing 203A without any special tooling features or assembly processes. The insert “tail” 270 also has a web and gusset for additional strength. In order to accommodate the webbing on the insert “tail” 270 there is a slot 272 cut in each latch point on the retention ring. The latch point on the retention ring is widened to ensure that the proper level of shear area is retained for the stresses and strains the part is subjected to under the hydraulic surge's mechanical load (i.e., during surge). Tab features 260 and central square opening in retention ring 205 are strategically positioned to avoid disruption of flow conditioning prior to irrigation fluid entry into the inlet of insert 201.
Retention ring 205 is retained in housing 203A by a snap undercut or groove cut into the interior wall of the housing. Retention ring has a circumferential raised boss or ridge dimensioned to snap-fit into the housing's snap undercut, thereby securing the retention ring in place and latching any installed fluidic insert 201 in place. This is a critical aspect since applicants have found that if the ring is allowed to move, then insert retention is compromised. Further to that applicants are relying on the filter 206 to serve as a backup support to stop the retention ring from flexing or moving under the forces of the hydraulic surge.
Retention ring 205 is preferably molded out of a conventional plastic resin as used in the rest of the sprinkler assembly. Similar material selection guarantees that there are no unexpected chemical or environmental reactions with other subcomponents. If needed, for added strength, the ring can be molded from a resin with glass reinforcement.
Applicants have determined that nozzle assembly 205 provides a uniquely advantageous solution to the problem because it will fit into the pre-existing package, allows the use of plastic material and a single component for economic purposes, and does not have any effect on external appearance or fluidic performance as other reinforcing fasteners would. Furthermore the retention ring concept is readily adapted for use in other sprinkler head-Fluidic Nozzle housings. Due to a number of manufacturing requirements, applicants were not able to implement other designs to retain the inserts in the housing. Some ideas that were considered include:
(a) ultrasonically welding the fluidic insert into the housing—this was not desirable as welding has been found to damage the critical spray geometry and affect performance;
(b) using an external spring steel ring—Placing a generic spring steel ring around the perimeter of the housing (e.g., 103) could achieve the purpose but requires enough space on the front of the fluidic inserts to capture the ring—this external ring also poses a potential problem in damaging annular seals on the sprinkler pop-up assembly; and
(c) “Nailing”—through an access hole in the housing; a metal or plastic rod could have been driven into the insert; although this is an extremely robust method it creates a number of issues. (i) It creates a leak path for the irrigation fluid, (ii) poor repeatability in installation force and location could damage critical spray geometry, and (iii) the added cost of multiple parts was deemed not economically feasible.
Another embodiment substitutes an internal spring steel ring 505 (see
Special Considerations for Spray Pattern Uniformity:
As noted above, a fluidic nozzle creates a stream of fluid that oscillates within an included angle, known as the fan angle. The distribution of the fluid within this fan will vary depending on the type of fluidic circuit used. For example, in a mushroom circuit (e.g., as shown in
The fluid distribution can be important in several applications for fluidic nozzles. In an irrigation nozzle, for example, it is desirable to distribute water evenly over a given area or shape (for example, a quarter circle.) If a heavy-ended fluidic were to be used in such a case, more fluid would be deposited on the edges of the spray, and less in the center. Furthermore, since the trajectory of the droplets is related to droplet size and velocity, the irrigation nozzle will tend to throw water further on the ends than in the middle.
In use, fluidic circuit 601 sweeps a stream of fluid back and forth across the outlet's opening. As the heavy stream passes over protrusion 600, the flow is diverted over and around the protrusion 600, and broken into smaller drops. When the stream continues on to the other extreme of its travel, it is not affected by protrusion 600. In the exemplary embodiment shown in FIG. 25., it was deemed desirable to smooth the heavy center of the spray without affecting the crisp edges of the spray. Therefore, first and second protrusions 600 are located closer to the outlet's vertical splitter 101A than to the outer edge of the spray.
a and 26b show two options for breaking up the heavy ends of spray. One large protrusion 602 can be used, centered within the sweep of the oscillating stream (
The effect of these protrusions on the fluidic's spray pattern is illustrated in
Larger protrusions will have more of an effect on the spray. Applicants were initially successful with protrusions 5-15% the height of the fluidic circuit's vertical extent, and later work has yielded beneficial results with protrusions or bumps with a height 5-15% the height of the fluidic circuit's vertical extent. The diameter of the protrusions can vary from a fraction of the throat width (as in the embodiment of
There are various applications for a fluidic circuit including the pattern-modifying bumps, in accordance with the present invention. For example, a lawn sprinkler pop-up head can include one or more fluidic circuits adapted to spray over a very specific area, preferably with optimum spray pattern uniformity or irrigation fluid distribution uniformity. An exemplary sprinkler assembly has a sprinkler housing (e.g., 103, as shown in
In addition to the exemplary embodiments shown in the Figs, it is possible to employ an embodiment using only one circuit. The mushroom circuit shown in
Those having skill in the art will recognize that the structures, apparatus and methods of the present invention make available a long throw Pop-Up Irrigation Nozzle assembly having no oscillating or rotating parts, with a cylindrical body having a fluid inlet and a sidewall defining at least one fluidic circuit that is configured to generate a selected spray pattern when irrigation fluid flows through the body. In order to throw long distance, droplet velocity, droplet size and droplet initial aim angle are used to determine the throw to provide a low precipitation rate (“PR”) for fluidic sprays of irrigation fluid, whereby the nozzle assembly and method of the present invention achieve a PR of 1 in/hr or less and good spray distribution with a scheduling coefficient (“SC”) of about 1.5, all without utilizing any moving components, and so provide a significantly more cost effective nozzle assembly, as compared to prior art rotator nozzles.
Testing of later developed fluidic irrigation assemblies such as those shown in
The nozzle assemblies illustrated herein may also be used with a “Yawed” fluidic oscillator as an insert (e.g., 701 or 801, as shown in
Having described preferred embodiments of a new and improved method, it is believed that other modifications, variations and changes will be suggested to those skilled in the art in view of the teachings set forth herein. It is therefore to be understood that all such variations, modifications and changes are believed to fall within the scope of the present invention, as set forth in the following claims.
This application claims priority to related and commonly owned U.S. provisional patent application No. 61/012,200, filed Dec. 7, 2007, the entire disclosure of which is incorporated herein by reference. This application also claims priority to related and commonly owned U.S. provisional patent application Nos. 61/136,744 and 61/136,745, each filed Sep. 30, 2008, the entire disclosures of which are also incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61012200 | Dec 2007 | US | |
| 61136744 | Sep 2008 | US | |
| 61137745 | Aug 2008 | US |
