Patent Application
20070295840
1. Field of the Invention
This invention relates to fluid handling processes and apparatus. More particularly, this invention relates to new methods and apparatus for enclosing fluidic oscillators or inserts so as to improve their performance.
2. Description of the Related Art
Fluidic inserts or oscillators are well known for their ability to provide a wide range of distinctive liquid sprays. The distinctiveness of these sprays is due to the fact that they are characterized by being oscillatory in nature, as compared to the relatively steady state flows that are emitted from standard spray nozzles.
A fluidic insert is generally thought of as a thin, rectangular member that is molded or fabricated from plastic and has an especially-designed, uniform depth, liquid flow channel fabricated into either its broader top or bottom surface, and sometimes both (assuming that this fluidic insert is of the standard type that is to be inserted into the cavity of a housing whose inner walls are configured to form a liquid-tight seal around the insert and form an outside wall for the insert's boundary surface/s which contain the especially designed flow channels). Pressurized liquid enters such an insert and is sprayed from it. See, for example the fluidic insert (18) and housing (10) in FIG. 1 of the present Assignee's U.S. Pat. No. 7,014,131.
Although it is more practical from a manufacturing standpoint to construct these inserts as thin rectangular members with flow channels in their top or bottom surfaces, it should be recognized that they can be constructed so that their liquid flow channels are placed practically anywhere (e.g., on a plane that passes though the member's center) within the member's body; in such instances the insert would have a clearly defined channel inlet and outlet. For example, see the present Assignee's U.S. Pat. No. 5,820,034 which shows a two-part (50a, 50b), fluidic insert whose exterior surface is cylindrical so that this insert can be fitted into a similarly shaped housing (72).
Additionally, it is know that such fluidic inserts may be formed by using projections that extend from a base plate so as to form essentially the central part of a fluid circuit that does not have any sidewalls. The sidewalls for the flow through such inserts are formed by the boundary walls of the enclosing housing. See FIG. 2C of the present Assignee's U.S. Patent Publication No. 2006-0226266. The advantage of a fluidic insert constructed in this manner is that the overall width of the insert and its housing can be reduced, which can be important for various spraying applications (e.g., windshield washer applications) which impose geometric restrictions on allowable insert widths.
Regarding such fluidic inserts, it is also known that their flow channels need not be of a uniform depth. For example, see the present Assignee's U.S. Pat. No. 4,463,904, U.S. Pat. No. 4,645,126 and RE38,013 for fluidic oscillators in which the bottom surfaces of these channels are discretely and uniformly sloped so as to impact the ways in which the sprays from these oscillators spread as the move away from the oscillator's outlet.
There are many well known designs of fluidic circuits that are suitable for use with such fluidic inserts. Many of these have some common features, including: (a) at least one power nozzle configured to greatly accelerate the movement of the liquid that flows under pressure through the insert so that it separates from the walls downstream of the power nozzle so as to form an essentially “free” jet downstream of the power nozzle, (b) an interaction chamber through which the liquid flows and in which the flow phenomena is initiated that will eventually lead to the spray from the insert being of an oscillating nature, (c) an liquid inlet, (d) a pathway that connects the inlet and the power nozzle/s, and (e) an outlet or throat from which the liquid sprays from the insert.
Examples of fluidic circuits may be found in many patents, including the present Assignee's U.S. Pat. No. 3,563,462 (Bauer), U.S. Pat. No. 4,052,002 (Stouffer & Bray), U.S. Pat. No. 4,151,955 (Stouffer), U.S. Pat. No. 4,157,161 (Bauer), U.S. Pat. No. 4,231,519 (Stouffer), which was reissued as RE 33,158, U.S. Pat. No. 4,508,267 (Stouffer), U.S. Pat. No. 5,035,361 (Stouffer), U.S. Pat. No. 5,213,269 (Srinath), U.S. Pat. No. 5,971,301 (Stouffer), U.S. Pat. No. 6,186,409 (Srinath) and U.S. Pat. No. 6,253,782 (Raghu).
Despite much prior art relating to the development of fluidic circuits, the nature of the housings or enclosures that surround fluidic oscillators have changed only slowly over the years. For example, the overall exterior shape of a fluidic oscillator's automotive windshield washer is invariably aerodynamically configured from its rear to its front face in consideration of the fact that this housing will be mounted on an automobile's hood and in front of its windshield.
FIG. 2 of U.S. Pat. No. 6,062,491 shows a more recent housing design that is notable for its having two cavities into which cooperating fluidic oscillators are inserted. As an alternative to such configurations, it can be noted that it is also known to place more than one fluidic circuit on the same insert, see the “double spray” insert or oscillator of the present Assignee's U.S. Pat. No. 7,014,131.
Housings for fluidic inserts have also been designed for specific applications. For example, see FIGS. 5 and 8C of the present Assignee's USPPN 2004-0227021 which show a housing whose exterior surface has been especially configured to allow this housing and its enclosed fluidic oscillator to be used as part of a “quick disconnect” nozzle assembly.
For an example of a housing that is suitable for showerhead applications, see FIG. 15A of the present Assignee's U.S. Pat. No. 7,111,800. Shown there is a housing which also has an exterior surface that has been especially configured to allow this housing to be used as part of a specialized nozzle assembly (i.e., a showerhead). It also has a cavity that is especially configured to accept a stack of fluidic oscillators in which the centerlines of the adjoining oscillators have a specified, included angle of divergence.
While one generally thinks of the enclosures for these inserts or oscillators as being of an almost totally enclosing nature (in which case, we herein refer to them as housings), this need not be the case. FIG. 3 of the present Assignee's U.S. Pat. No. 5,845,845 shows a “lid” (32) for enclosing only the boundary surface of the oscillator in which the fluidic circuit is located. Note that its knobs (45, 46) are for securing the lid and are not part of the fluidic circuit.
One common feature that may not have been noticed in examining the early versions of the housings previously mentioned is that they all provide for what is called “frontal entry” or loading of the fluidic insert into the housing. More recently, it was discovered that there are advantages to sometimes designing these housings so that they provide for “rear entry” of the fluidic inserts into the housings. See FIGS. 7-8 and 10 of present Assignee's USPPN 2006-0108442.
The FIGS. 7A-7D of USPPN 2006-0108442 show various views of an enclosure or housing that has both a rear surface, with an opening which allows for the rear loading of a fluidic oscillator, and a front surface which has a portion that is configured so as to provide a throat for the fluid that flows from the fluidic oscillator. These types of housings are notable for, among other things, being the first of their type that have an element of the fluidic circuit (e.g., a throat) fabricated into the front face of the housing.
Previously and with “front entry” housings, all of the elements of a fluidic circuit were, out of necessity, always molded directed into the fluidic insert—the front face of the fluidic insert was the most downstream point of the passage from which the fluid spray issued.
The FIGS. 8A-8C of USPPN 2006-0108442 show views of the front faces of various “showerhead” enclosures that have been fabricated with many especially oriented and configured cavities in a single housing. A key advantage of such enclosures is that they provide the opportunity to use various unique arrays of fluidic oscillators to create a combined spray whose droplet flow characteristics are unique in comparison to those sprays that could be produced by any other known means.
The FIG. 10 of USPPN 2006-0108442 shows the front face of a multi-cavity “showerhead” enclosure that allows for a multiple mode of spray operation. The perimeter of this housing has a ring of conventional orifices that emit a conventional, non-oscillating jet spray intended primarily for rinsing purposes. Within this ring there exists an octagonal array of eight fluidic-oscillator-containing passages and at the center of this face is a triangular array of three fluidic-oscillator-containing passages.
The enclosures for fluidic oscillators can also be of a two-part construction (i.e., using a secondary housing which is then inserted in a specified manner into a primary housing). This proves to be especially useful in those instances in which it is desired to make the enclosures such that they allow one to adjust the direction of the spray that flow from the oscillator. The FIGS. 3A-3B and 4A-4B of the present Assignee's USPPN 2006-0226266 shows such an adjustable spray nozzle with its secondary (30) and primary (50) housings.
As fluidic oscillators have continued to be used in more types of applications, the opportunity has arisen to re-examine and improve upon the design of their housings or enclosures as a way to improve upon the overall spraying performance of the nozzle assemblies, etc. which use fluidic oscillators.
There has been summarized above, rather broadly, the prior art that is related to the present invention in order that the context of the present invention may be better understood and appreciated. In this regard, it is instructive to also consider the objects and advantages of the present invention.
It is an object of the present invention to provide an assortment of individual housings or enclosures for fluidic inserts or oscillators that can be helpful in improving upon the actual spray performance of the spray devices or nozzle assemblies that utilize fluidic oscillators.
It is an object of the present invention to provide fluidic spray assemblies (i.e., fluidic oscillators with novel enclosures) that can provide specific types of desired sprays that have heretofore not been achievable with conventional fluidic technology.
It is an object of the present invention to provide improved and more versatile fluidic inserts and their enclosures which are ideally designed for a wide range of windshield washer applications.
It is an object of the present invention to provide improved enclosures and fluidic inserts that are ideally designed for an assortment of commercial cleaning applications.
It is an object of the present invention to provide enclosures and fluidic inserts that allow a user to better direct and control the location of the areas being wetted by the sprays from such devices.
These and other objects and advantages of the present invention will become readily apparent as the invention is better understood by reference to the accompanying summary, drawings and the detailed description that follows.
Recognizing the need for the development of improved fluidic oscillators and their enclosures, the present invention is generally directed to satisfying the needs set forth above and overcoming the limitations seen in the prior art devices and methods.
In accordance with the present invention, an improved fluidic oscillator, of the type that operates on a pressurized liquid flowing through it to generate an oscillating spray of liquid droplets, includes a member into which is fabricated a two-portion, flow channel, with this first portion configured so as to create the flow phenomena in the member that yields the spray's oscillating nature, and wherein its second portion is configured so as to provide a plurality of throats by which the pressurized liquid exhausts into the surrounding environment.
In a second preferred embodiment, the present invention takes the form of an enclosure for a fluidic oscillator and includes a body having interior and exterior surfaces, with a portion of the body's interior surface configured to attach to the oscillator's boundary surface which contains its fluidic circuitry so as to form an enclosed pathway through which the liquid may flow, and wherein a portion of the body's interior surface is configured so as to provide a plurality of throats through which the pressurized liquid may exhaust.
Thus, there has been summarized above, rather broadly and understanding that there are other preferred embodiments which have not been summarized above, the present invention in order that the detailed description that follows may be better understood and appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the later presented claims to this invention.
Before explaining at least one embodiment of the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
A common problem encountered in developing and producing fluidic oscillators or inserts for use in automotive windshield applications is designing a fluidic circuit which can give the desired spray characteristics (e.g., at flow rates of 400 ml/minute and operating pressures of 9 psig, uniform coverage with spray droplets of a target area located approximately 25 cm in front of the sprayer and having a target area width of approximately 80 cm) and which can be fitted into a housing which is very limited on its allowable size. Because such housings often are situated in locations on an automobile's hood that are quite visible, their allowable dimensions are often dictated by aesthetic considerations (e.g., typical acceptable widths are on the order of 10-12 mm). The consequence of this is that the spray from the windshield washers situated in such housings must have, what is referred to as, a large horizontal fan angle, φ (i.e., defined by the lateral or horizontal boundaries of the region wetted by the spray).
Since such inserts and their enclosures are typically made by plastic injection molding methods, those knowledgeable with such manufacturing methods will understand that such manufacturing methods impose further constraints on the geometry of such inserts and their enclosures. For example, a 12 mm wide housing can only accommodate a fluidic insert having a maximum width of about 9 mm since the wall thickness of such housings must typically be about 1 mm or larger.
In striving to improve the performance of various types of fluidic sprayers, we have discovered that there are significant opportunities to create and introduce new enclosures for these fluidic oscillators that appreciably improve their performance. We have also found that still further novel designs can be provided for a generalized fluidic oscillator which can increase its performance
A preferred embodiment of the present invention 2 takes the form of a housing 10 which has a front portion 12 into which has been molded one or more elements 14 of the fluidic circuit 32 which is inscribed or molded into the fluidic insert 30 that is inserted into the housing from an opening 18 that exists in its rear face 16. See
A word needs to be mentioned regarding the novelty of this embodiment. For those knowledgeable in the design of fluid nozzles and advanced fluid dynamic principles, it should be noted that it was not an obvious matter that the situation shown here, in which multiple throats are fed by a single, relatively larger scaled fluidic circuit, would actually yield oscillating flows from each of the downstream throats. The fluid flow is these passages is very complicated and is not amenable to a theoretical solution; thus, extensive experiments had to be conducted to better understand these types of flows. It was only as a result of these experiments that it was discovered that the flow geometry shown in
It can be seen in
A second preferred embodiment of the present invention is the fluidic insert or oscillator 4 shown in
This insert is seen to have a second portion with a novel front wall 50 into which are molded multiple throats: two lower throats 52A, 52B with their adjoining, downstream expansion passages 54A, 54B and a single upper throat 52C and its downstream expansion passage 54C. Pressurized liquid enters this insert and oscillating liquid sprays issue from each of its three throats.
In this embodiment, the upstream elements of the fluidic circuit shown in
A third preferred embodiment of the present invention that is similar to that shown in
It can be noted that the present invention was discovered and created as a result of the continuing pressures to minimize the size of the fluidic spray devices for a wide range of applications, including those for windshield washers. The herein disclosed split or multiple throat housings are seen to allow for the use of only a single fluidic insert, with its advantageous larger flow passages, to be used with such housings.
The advantages of using a single insert or oscillator, over the multiple inserts, previously referenced as being shown in U.S. Pat. No. 6,062,491, U.S. Pat. No. 7,111,800 and USPPN 2006-0108442, to achieve the same spray coverage have been experimentally found to be: (a) better high viscosity or low temperature operating performance, (b) less chance of insert clogging, (c) higher possible flow rates for a given size or space restriction, and (d) higher potential exit velocities.
The prior state of the art for better spray distribution from automotive windshield washer devices often involved the use of “double spray” inserts or nozzles (i.e., two fluidic circuits on one insert, with the bottom circuit distributing fluid over a wide pattern toward the lower portion of the windshield and the top circuit distributing the spray over a smaller pattern toward the upper portion of the windshield).
The limits of available fluid flow and pressure on automotive vehicles often required that each of these circuits have smaller dimensions than those of the single circuit devices which they were replacing. However, this type of configuration presented performance problems since such smaller oscillators cannot perform as well as larger oscillators in higher viscosity fluids, such as cold washer fluid.
An advantage of the present invention is that it allows for the use of a larger dimensioned insert or oscillator (e.g., such as would be used in a single spray application) to distribute fluid like the smaller oscillators used in the double insert housings that were previously referenced in U.S. Pat. No. 6,062,491. The larger dimensioned inserts of the present invention offer significantly improved spray patterns.
The foregoing is considered as illustrative only of the principles of the invention. Accordingly, all suitable modifications and equivalents of the present disclosure may be resorted to and still considered to fall within the scope of the invention as hereinafter set forth in claims to the present invention.
This application is a continuation-in-part of Assignee's U.S. Pat. No. 7,111,800, issued Sep. 26, 2006 and filed Sep. 29, 2003 and pending patent application U.S. Ser. No. 11/245,396, USPPN 2006-0108442, Attorney Docket No. BWLS29, filed Oct. 6, 2005. This application claims the benefit of Provisional Patent Application No. 60/808,173 filed May 24, 2006 by the present inventors. The teachings of these prior patent documents are incorporated herein by reference to the extent that they do not conflict with the teaching herein.
| Number | Date | Country | |
|---|---|---|---|
| 60808173 | May 2006 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10673727 | Sep 2003 | US |
| Child | 11805802 | May 2007 | US |
| Parent | 11245396 | Oct 2005 | US |
| Child | 11805802 | May 2007 | US |
