Patent Application
20080191059
This invention relates to an irrigation spray nozzle and, more particularly, to a spray nozzle with an inverted water flow.
Irrigation nozzles have been adapted for mounting on a fixed or pop-up water supply riser. Spray type irrigation nozzles typically include at least one discharge orifice shaped to distribute water in a stream or spray pattern of a pre-selected arcuate span. One common form of such spray nozzle includes an upper deflector assembled to a lower nozzle body designed for mounting onto the riser. The deflector and nozzle body cooperatively define the discharge orifice with the selected arcuate span through which water is projected from the nozzle. Such spray nozzles commonly include a series of models that each produce a different spray pattern, such as, for example, a quarter-circle, half-circle, and full-circle spray pattern.
One shortcoming of many commercially available spray nozzles is their tendency to distribute water in a doughnut-shaped watering pattern caused by less water being distributed in the regions relatively close to and distant from the nozzle. In other words, such spray nozzles distribute most of the water to a mid-range region from the nozzle. This limited water distribution results from the arrangement between the upper deflector and the lower nozzle body. For example, water is directed upwardly from the lower nozzle body to impact the upper deflector. The deflector then redirects the water to the surrounding terrain.
In such commercially available spray nozzles, the water stream is generally comprised of two portions: an upper portion and a lower portion. The upper portion of the stream typically has a relatively low velocity because it has experienced frictional drag across the deflector. In contrast, the lower portion of the stream generally has a relatively high velocity because it has not experienced this frictional drag. As both water stream portions are emitted outwardly, gravity causes the lower velocity water to interfere with the higher velocity water, resulting in an intermediate velocity water stream that irrigates with only a mid-range doughnut pattern about the nozzle.
Accordingly, there is a need for a spray nozzle that reduces interference between low velocity and high velocity portions of the water stream. This would provide an enhanced distribution pattern by increasing the amount of water distributed to terrain outside of the limited mid-range distance, i.e., to terrain relatively near to, as well as terrain relatively distant from, the nozzle.
With reference to
In general, the inverted pattern is created by channeling the supply water first toward the top of the nozzle 10 and then back down to the deflector 12. That is, a series of upward flow passages 14 channels the water initially to a chamber 16 above the deflector 12. The water then flows from the chamber 16 through a series of downward flow passages 18 onto a top surface 20 of the deflector 12 to be redirected outward from the nozzle 10 for irrigation. Inverting the direction at the deflector 12 causes the high and low velocity components to switch as well.
More specifically, the nozzle 10 preferably includes a nozzle base 22, a nozzle body 24, and a nozzle cover 26, which, together, define the upward and downward flow passages 14 and 18, the chamber 16, and one or more deflector surfaces 20 of the nozzle 10. These components preferably are formed of a molded plastic material, or other suitable material, and although they are shown as three separate parts, they also may be combined to form one part or two parts.
With reference to
The upper end 28 of the nozzle base 22 also defines one or more flow passages 31 for the flow of water vertically upward from the water source and through the nozzle base 22. In this instance, there are four flow passages 31 with a circular cross-section and spaced circumferentially an equal distance from the ones directly adjacent thereto. The nozzle base 22 further includes one or more deflector surfaces 20. In this instance, there are four deflector surfaces 20 in between two flow passages 31 and spaced circumferentially an equal distance from the ones directly adjacent thereto. The flow passages 31 extend through seats 40 that define a top seating surface 42, which is elevated with respect to the deflector surfaces 20. Thus, the nozzle base 22 provides upward water flow and deflects water directed downward from the chamber 16 against the deflector surfaces 20 outward from the nozzle 10.
As illustrated in
In
The upward flow passages 14 are connected to the flow passages 31 of the nozzle base 22 so that water travels vertically upwardly from the nozzle base 22 through the flow passages 31 and, then, through the upward flow passages 14 to the chamber 16. In each of the nozzle bases 20a-c of
As illustrated in
With reference to
Each nozzle body 24a-b includes one or more arcuate tabs 60 that project downward from a portion of the outer periphery of the nozzle body 24a-b. Each tab 60 engages a landing 62 formed at the outer periphery of each deflector surface 20 between adjacent seats 40. The number and arrangement of arcuate tabs 60 indicate the nature of the nozzle 10, i.e., the three tabs 60 of nozzle body 24a of
In
As shown in
The flow throttling screw 36 extends through the central hub 70 and the central bore 34 of the cover 26 and the nozzle base 22, respectively. The flow throttling screw 36 is manually adjusted to throttle the flow of water through the nozzle 10. The throttling screw 36, includes a head 72, is seated in the central hub 70 of the cover 26 and may be adjusted through the use of a hand tool. The opposite end 74 of the screw 36 is in proximity to an inflow port 84 protected from debris by a filter 76. Rotation of the head 72 results in translation of the opposite end 74 for regulation of water inflow into the nozzle 10. The screw 36 may be rotated in one direction to decrease the inflow of water into the nozzle 10, and in the other to increase the inflow of water into the nozzle 10.
The filter 76 includes an upper lip 78 for mounting the filter 76 to an annular inner surface 80 of the nozzle base 22. The lip 78 is adapted for press fit or slide fit reception onto the inner surface 80 of the base 22. The filter 76 is located upstream of the flow passages, chambers, and deflectors of the nozzle 10 and restricts grit and other debris from flowing into the nozzle 10 and becoming lodged in areas that may cause the operation of the nozzle 10 to be hindered.
When water is supplied to the nozzle 10, it flows upwardly through the filter 76 and then upwardly through the flow passages 31 of the nozzle base 22. Next, water flows upwardly through the upward set of flow passages 14 of the nozzle body 24 and into the chamber 16. Water is then redirected downwardly through the downward set of flow passages 18 of the nozzle body 24, to impact on one or more of the deflector surfaces 20 of the nozzle base 22 to be redirected outwardly from the nozzle 10 for irrigation.
The down flow approach to the deflector 12 of the nozzle 10 results in an inverted velocity profile in the water leaving the deflector surface 20 in comparison to the conventional up flow approach to the deflector. The inverted water velocity profile produces a more uniform distribution of water to surrounding terrain because high velocity water is in the upper region of the profile and the lower velocity water is in the lower region of the profile, and therefore, they do not directly interfere with one another.
More specifically, in conventional spray nozzles, the water is directed upward to the deflector for deflection outward from the nozzle. The surface drag on the deflector results in low velocity water leaving the nozzle in the upper region of the profile, and higher velocity water leaving the nozzle in the lower region of the profile. Gravity then causes the lower velocity water to fall into the higher velocity water. This interference creates a compressed profile of a mid-range velocity which causes the water to carry over the desired watering area close to the nozzle and to fall short of the desired watering area furthest from the nozzle. As a result, a doughnut shaped distribution pattern around the nozzle is formed with water distributed primarily to a limited mid-range distance from the nozzle.
In contrast, the water deflected from the deflector surfaces 20 of the deflector 12 of the nozzle 10 does not interfere in this manner, resulting in a more uniform water distribution pattern. The limitation on interference is produced by the inverted flow profile. With the deflector surface 20 at the bottom of the water profile, the lower velocity flow created by the drag across the deflector surface is on the bottom portion of the profile, whereas the higher velocity water is overhead and above. Thus, lower velocity water will not tend to interfere with the higher velocity water.
In addition, the outer annular region of each deflector surface 20 is formed with radially extending grooves 50 to increase the surface area of the deflector surface 20 at the outermost region. The grooves 50 increase the frictional drag on the water across the deflector surface 20 to further reduce the velocity of the water at the bottom of the profile leaving the deflector 12. This enhances the water distribution for the area closer to the nozzle 10, while allowing the higher velocity water of the upper portion of the profile to reach the outermost area desired to be watered by the nozzle 10.
The characteristics of the water discharge profile may be tailored by changing certain aspects of the nozzle 10. For example, although four upward flow passages 14 are shown in
The flow characteristics of the water emitted from the nozzle 10 may be modified for different models by changing certain dimensions of the nozzle 10, such as, for example, the cross-sectional dimension of the upward and downward flow passages 14 and 18. The diameter of each upward flow passage 14 may be different than the diameter of each downward flow passage 18. The ratio of these diameters may be adjusted to achieve desirable water pressure and velocity values at the deflector surfaces 20 of the nozzle base 22. The use of two orifices in series provides significant advantages over nozzles having only one orifice.
For example, the cross-sectional diameter of the upward flow passages 14 may be selected so that the diameter is relatively large compared to that of the downward flow passages 18. When the ratio of these diameters is relatively large, the pressure at the downward flow passages 18 and the velocity of the emitted water are also relatively large. In other words, the use of upward flow passages 14 with relatively large diameters results in a relatively insignificant loss of water pressure and velocity for water flowing through the nozzle 10.
The diameters of the upward and downward flow passages 14 and 18 may be modified for different models. As the ratio of the diameters is modified, the flow characteristics of the nozzle 10 are changed. More specifically, as the ratio is reduced, the pressure at the downward flow passages 18 and the velocity of the emitted water is correspondingly reduced. In other words, as the diameter of the upward flow passages 14 are made narrower relative to the downward flow passages 18, water flowing through the nozzle 10 experiences a significant loss of pressure and velocity. Accordingly, manufacturing nozzles having different flow passage diameters allows for the control of desired pressure and velocity characteristics.
In this manner, it is possible to design a family of nozzles with different throw radiuses that have the same precipitation rate, i.e., the same quantity of emitted water for a given unit of area and time. For instance, it may be desired to have a nozzle with a 16 foot radius and a nozzle with an 8 foot radius with both nozzles having the same precipitation rate. Assuming predetermined cross-sectional areas for the upward and downward flow passages of the 16 foot nozzle (A14 and A18) for a desired arc, trajectory, and operating pressure, appropriate values for the cross-sectional areas of the upward and downward flow passages of the 8 foot nozzle (B14 and B18) may be calculated by applying principles of flow dynamics.
These values may be calculated in three steps. First, to reduce the throw radius in half, the velocity of water emitted from the 8 foot nozzle is reduced in half relative to the 16 foot nozzle. Second, in order to achieve a matched precipitation rate for the 8 foot nozzle having this reduced velocity, the cross-sectional area of the downward flow passage of the 8 foot nozzle, B18, must be half that of the 16 foot nozzle, A18, i.e., B18=0.5*A18. Third, the velocity of water emitted from the 8 foot nozzle is reduced in half by designing the 8 foot nozzle with the appropriate pressure-reducing ratio of (B14/B18)=1/SQRT (3)=0.58. In other words, the 16 foot and 8 foot nozzles may be designed with matching precipitation rates by designing the nozzles such that B18=0.5*A18=1.73*B14. Similar calculations may be performed to design other nozzle types having different throw radiuses but having the same precipitation rate.
The use of nozzles having flow passages 14 and 18 in series (rather than a single flow passage) provides additional advantages, including the ability to control and reduce exit velocities of emitted water. Reduced exit velocities limit the undesirable effect known as “misting.” High exit velocities cause relatively high levels of internal turbulence within the emitted water stream and cause the water stream to experience relatively greater shear forces from the surrounding air. These combined effects tend to tear smaller droplets from the emitted water stream, i.e., to cause the emitted water stream to mist. In turn, this results in high evaporation rates and wind drift, both of which reduce irrigation efficiency.
Further, the upward and downward flow passages 14 and 18 can be substantially larger in diameter than a single orifice (such as that used in a conventional up flow nozzle). For nozzles 10 with orifices in series, the ratio of the orifice size affects pressure and exit velocity characteristics. For single orifice nozzles, in contrast, these characteristics may often be determined by the size of the single orifice and may require that the single orifice be very small. Accordingly, the use of relatively large orifices in series reduces the sensitivity of nozzles to clogging with contamination that would otherwise occur in conventional nozzles employing a relatively small single orifice.
Water flow characteristics may be modified in other ways. For instance, one or more of the upward flow passages 14 of the nozzle body 24 may be plugged or blocked to match the number of open upward and downward flow passages of the nozzle body 24, thereby achieving desired pressure and velocity values. By way of example, the quarter-circle nozzle body 24a shown in
In
As shown in
The deflector surfaces 120c-d each define a relatively narrow and elongated flow channel compared to the first set. The deflector surfaces 120c-d each include an inner portion 144 that slopes relatively steeply downwardly to a nadir and, then, slopes relatively gently upwardly to transition into an outer portion 146. The sides of the deflector surfaces 120c-d define a relatively acute angle compared to the first set 120a-b. The deflector surfaces 120c-d are oriented non-radially to direct water to each side of the nozzle 110 beyond the close in area of coverage of the first set 120a-b. Thus, for example, the second set of deflector surfaces 120c-d each distribute water to a relatively distant area, such as between a 4′ by 6′ area and a 4′ by 15′ area, on opposite sides. Taken together, the deflector surfaces 120a-d provide continuous coverage for a 4′ by 15′ long narrow strip on each side of the nozzle 110.
As shown in
As shown in
The barrier walls 171 are positioned so that three of the upward flow passages 114b-d feed into chamber 116a, the larger chamber. The barrier walls 171 are also positioned so that two of the downward flow passages 118c-d extend into chamber 116a. These two downward flow passages 118c-d lie above deflector surfaces 120c-d, and, during operation, direct water downwardly against these surfaces. By orienting the barrier walls 171 to include three of the upward flow passages 114b-d, water flowing onto deflector surfaces 120c-d experiences relatively high pressure and velocity, thereby allowing distribution of water relatively distant from the nozzle 110.
In contrast, the barrier walls 171 are positioned so that only one of the upward flow passages 114a feeds into chamber 116b, the smaller chamber. During operation, water flows through the one upward flow passage 114a, into chamber 116b, through the two downward flow passages 118a-b, and onto deflector surfaces 120a-b. By orienting the barrier walls 171 to include only one of the upward flow passages 114a, water flowing onto deflector surfaces 120a-b experiences relatively low pressure and velocity, thereby allowing distribution of water relatively close to the nozzle 110. Thus, barrier walls 171 may be used to isolate one or more upward and downward flow passages 114 and 118 from others to provide different throw distances for the different deflector surfaces120a-d.
Adjustments, such as those described above, may be made to allow fine tuning of the nozzle 110 so that it exhibits desired pressure and velocity characteristics. For example, the cross-sectional areas of the upward and downward flow passages 114 and 118 may be varied to alter pressure, velocity, and throw distance, as desired.
Like the side strip nozzle 110, the corner strip nozzle 210 preferably includes a nozzle base 222 (
As shown in
As shown in
As shown in
The nozzle cover 226 of the corner strip nozzle 210 is shown in
The barrier walls 271 are oriented so that one upward and one downward flow passage correspond to each chamber. More specifically, one upward flow passage 214a feeds into, and one downward flow passage 218a extends into, chamber 216a, the smaller chamber. Similarly, the other upward and downward flow passages 214b and 218b feed and extend into, respectively, chamber 216b, the larger chamber. The downward flow passages 218a and 218b are situated above deflector surfaces 220a and 220b and direct water downwardly onto these deflector surfaces.
The barrier walls 271 are oriented so that the upward flow passage with the smaller orifice size, 214a, feeds into the smaller chamber 216a, and conversely, so that the upward flow passage with the larger orifice size, 214b, feeds into the larger chamber 216b. By designing chamber size and orifice size in this manner, water flowing onto the relatively elongated deflector surface 220b experiences relatively high pressure and velocity for distribution of water relatively distant from the nozzle 210, while water flowing onto the relatively wedge-shaped deflector surface 220a experiences relatively low pressure and velocity for distribution of water relatively close to the nozzle 210.
The foregoing relates to preferred exemplary embodiments of the invention. It is understood that other embodiments and variants are possible which lie within the spirit and scope of the invention as set forth in the following claims.
