1. Field of the Invention
The present invention relates to fluidic circuits and nozzle assemblies configured with fluidic oscillators and other fluidic circuits.
2. Discussion of the Prior Art
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, the oscillating stream will tend to dwell briefly at the extremes of its travel, creating a fluid distribution or spray pattern that is called a heavy-ended fan. Some circuits may include a splitter, which can increase the maximum fan angle and spray velocity. In this case, the oscillating stream will tend to dwell on the splitter, causing a fluid distribution or spray pattern that is called a center-heavy fan.
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. Many irrigation nozzle assemblies have spray patterns with several heavy bands.
Another common application for fluidic nozzles is to distribute windshield wiper fluid across a windshield, for cleaning. In this case, parts of the windshield may be covered with large amounts of wiper fluid, while other parts get only a light coating. In many cleaning applications, it is desirable to distribute fluid as evenly as possible over specific areas.
There is a need, therefore, for a convenient, flexible, inexpensive and unobtrusive fluidic structure and fluid distribution or spray method to distribute fluid in a more uniform pattern, or to broaden the performance envelope of a given set of fluidic circuits.
Accordingly, it is an object of the present invention to overcome the above mentioned difficulties by providing a convenient, flexible, inexpensive and unobtrusive fluidic structure and fluid distribution or spray method to distribute fluid in a more uniform pattern, or to broaden the performance envelope of a given set of fluidic circuits.
In accordance with the present invention, a fluidic circuit and method can redistribute the bands of heavy flow, resulting in a more uniform flow distribution. Rather than introducing a new fluidic circuit which might carry its own advantages and disadvantages, this invention adds a feature that can be added to many fluidic circuit designs. The present invention is a passive solution, using no power or moving parts.
A bump or upwardly projecting protrusion or protuberance is added to the floor of the circuit downstream of the outlet's throat(s), near the heavy portion of the fan pattern or spray pattern defined by the oscillating stream of droplets. The protrusion projects “upwardly” in an arbitrary illustrative frame of reference and “upward” is a direction which is transverse to the direction of fluid flow, so that the protrusion projects into the passing flow of fluid (or “inwardly”).
In the exemplary embodiment, the 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 oscillating stream continues on to the end or extreme of its travel (at the edge of the fan pattern), the stream bypasses and 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 bumps or protrusions need not be circular in cross-section; an oval or 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 fan pattern defining 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 5-50% the height of the circuit. The diameter of the protrusions 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.
Referring now to
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. Housing 103 has a distal or top closed end with an axially aligned, threaded bore that threadably receives an axially aligned flow adjustment screw 104 which defines a flow-restricting valve plug end.
The cross sectional view of
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 more general terms, housing 103 provides an enclosure for a fluidic oscillator or circuit (e.g., 101) that operates on a pressurized fluid or liquid flowing through the oscillator to generate a liquid jet that flows from the oscillator and into a surrounding environment to form an oscillating spray of liquid droplets, where the oscillator has a boundary surface fabricated therein defining a channel (bounded by port 110) to provide a fluidic circuit whose geometry is configured to aid in establishing the oscillating nature of the spray of liquid droplets. Enclosure 103 includes or defines a body having an interior and an exterior surface; where a first portion of the interior surface is configured to attach to the oscillator boundary surface and form with the channel 110 an enclosed pathway through which the liquid flows. For the embodiments shown in
In accordance with the present invention, at least one throat in the second portion includes at least one bump, protrusion or protuberance (e.g., 600 or 604) configured to project upward or transversely into the outward flow of the pressurized liquid. 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 protrusion projects “upwardly” in an illustrative frame of reference wherein “upward” is a direction which is transverse to the direction of exhausting or spraying fluid flow, so that the protrusion projects into the passing flow of fluid (or “inwardly”) as that fluid passes through the outlet of the fluidic circuit or oscillator.
The enclosure can have a body configured as housing 103, with the exterior surface including a front (or exterior) face and a rear (or interior) face and an intermediate boundary surface that connects the faces, and the interior surface includes a passage (e.g., port 110) that extends between the faces, with the passage having a front and a rear section, the passage rear section forming a cavity having an opening in the body rear face (or interior) where the cavity is configured to allow for the insertion of a fluidic oscillator (e.g., 101 or 601) into the cavity, and where the passage front section is configured to include or define the throats (or outlet, where the fluid is exhausted). At least one throat in the front (or exterior) section includes at least one spray altering bump, protrusion or protuberance (e.g., 600) which is configured to project upwardly or transversely and into the flow of the exhausting pressurized liquid to alter the pattern or bands of liquid flow and to render a substantially uniform pattern from the jet's oscillating spray.
As noted above, a fluidic nozzle creates a stream of fluid that oscillates within an included angle, known as the fan angle (e.g., 60 degrees for fluidic 101 of
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 transversely projecting protrusion 600, the flow is diverted over and around the protrusion 600, and broken into smaller drops. When the laterally oscillating stream continues laterally on to the other extreme of its travel, it is not affected by protrusion 600. In the exemplary embodiment shown in
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
In addition to the exemplary embodiments shown in
Those having skill in the art will recognize that the structures, apparatus and methods of the present invention make available a fluidic oscillator adapted for use in a spray or nozzle assembly having no oscillating or rotating parts, with a body having a fluid inlet and a side all defining at least one fluidic circuit with an outlet configured with transversely projecting bumps (e.g., 600) or “speed bumps” that are placed to generate a selected spray pattern when fluid flows through the body. The fluidic circuit receives the fluid at its inlet and passes the fluid to its outlet, where the fluid oscillates in a patterned exhausted spray which passes, in places, past or over the bumps, and projects the fluid outwardly in the desired spray pattern.
While this fluidic circuit or oscillator structure has been described in an exemplary application employing a housing, the structure and method of the present invention is not limited to such applications. Generally speaking, the present invention comprises a fluidic oscillator (e.g., 601 or 701) with an inlet configured to receive pressurized liquid, an oscillating chamber in fluid communication with the inlet and configured to generate an oscillating liquid stream which oscillates through an oscillation fan pattern (e.g., as seen 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 ail such variations, modifications and changes are believed to fall within the scope of the present invention, as set forth in the claims.
This application claims priority to related and commonly owned U.S. provisional patent application No. 61/136,745, filed Sep. 30, 2009, the entire disclosure of which is incorporated herein by reference. This application is commonly owned with related U.S. patent application Nos. 61/012,200, 61/136,744 and 12/314,242 the entire disclosures of which are also incorporated herein by reference.
Number | Date | Country | |
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61136745 | Sep 2008 | US | |
61136744 | Sep 2008 | US |