The invention relates to a method and apparatus for generating low impact sprays, and more particularly to fluidic oscillator systems useful in liquid dispersal applications to efficiently distribute liquid in a controlled manner and in which ricochet of spray droplets from a surface is reduced and/or minimized.
Fluidic oscillators are used in many liquid dispersal applications to efficiently distribute the liquid in a controlled manner. In some of these applications, the spray is aimed at a very small angle of incidence to the surface on which the liquid is being distributed. One example is in vehicles in the rear window washer upon which it is desired to distribute liquid for cleaning purposes. Rear window washers generally need to have a wide output pattern to cover the entire wipe area. One feature of recent car designs is that the rear windows have curving tops. The curvature makes it difficult to aim the spray into the glass surface appropriately to distribute the liquid without causing overspray or ricochet of high velocity droplets from the glass surface. Both of the above effects result in wash fluid being wasted by delivering it to areas outside the glass.
One approach to solving this aiming problem is to reduce the velocity of the spray droplets so that they do not bounce off the glass surface. Traditional methods do not give an optimum solution, as described in the matrix below.
The object of the present invention is to provide a solution while providing adequate flow rate and proper velocity. According to the present invention, a number of different ways to generate the required low velocity sprays while keeping a reasonable nozzle profile are disclosed.
According to one method, a multiple power nozzle oscillator of the type in which the disclosed in FIG. 8 of Raghu U.S. Pat. No. 6,253,782 issued Jul. 3, 2001 combined with the bilevel filter arrangement shown in Srinath et al U.S. Pat. No. 6,186,409.
Still another embodiment of the invention takes the form of the bilevel reversing chamber oscillator shown in FIGS. 6A and 6B of the aforementioned Srinath et al U.S. Pat. No. 6,186,409.
Yet another embodiment of the invention employs a vortex valve to increase the resistance to inlet flow and a multiple power nozzle-type fluidic oscillator.
In yet a further embodiment and to show the versatility of the invention, the invention can use a conventional fluidic oscillator with control passages of the type disclosed in Stouffer U.S. Pat. No. 4,508,267, coupled with a vortex valve; or a conventional wall attachment, feedback type oscillator as disclosed in Bray U.S. Pat. No. 4,463,904; coupled with a vortex valve pressure reducer.
The method of the invention involves producing low energy spray droplets which are more adapted to adhere to a surface. A fluidic spray nozzle is connected to a source of liquid under pressure, and the velocity of the sprayed droplets issuing from the fluidic spray nozzles is reduced so that the spray droplets do not bounce off of the surface. The invention allows the design of the liquid spray with the following advantages:
The invention features the following:
A fluidic spray system for producing low momentum liquid droplets comprising in combination, a fluidic oscillator coupled to a supply of liquid under pressure and a vortex valve immediately upstream of said fluidic oscillator.
A fluidic spray system for producing a liquid spray in which the spray droplets have a low momentum and allows wide angle sprays to be delivered to a selected surface area without bouncing off of said selected surface, comprising, a fluidic oscillator connectable by a flow path reverser to a source of liquid under pressure and wherein said fluidic oscillator is selected from a multiple power nozzle oscillator, a reversing chamber oscillator, and a feedback oscillator, and including a non-restrictor pressure reducer upstream of said fluidic oscillator.
Optionally, the non-restrictor pressure reducer is a vortex valve.
The fluidic spray nozzle includes a first and second two-sided molded chip having a fluidic oscillator formed in the first side and a feed circuit formed in the second side, and reducing pressure by feeding liquid from the first side to the second side, and said flow reverser reversing the direction of liquid flow thereof.
A fluidic spray system for producing a liquid spray in which the spray droplets have a low momentum and allows substantially unrestricted flows to be delivered to a point of utilization on a surface comprising a fluidic oscillator having an input coupled to a supply of liquid under pressure and a vortex valve immediately upstream of the fluidic oscillator, the vortex valve having an output which is connected to the input of the fluidic oscillator.
A fluidic oscillator spray system for producing a liquid spray in which the spray droplets have a low momentum and allows for producing droplets of larger diameters and a narrower range of diameters for similar operating pressures.
The invention also features a method for producing low energy spray droplets which are adapted to adhere to a surface comprising, providing a fluidic spray nozzle connectable to a source of liquid under pressure, reducing the velocity of spray droplets issuing from the fluidic spray nozzle so that the spray droplets do not bounce off the surface.
The fluidic spray nozzle is selected from the following:
The fluidic spray nozzle includes a first and second two-sided molded chip having a fluidic oscillator formed in the first side and a feed circuit formed in the second side, and reducing pressure by feeding liquid from the first side to the second side, and reversing the direction of liquid flow thereof.
The object of the invention is to provide an improved fluidic spray system in which the liquid droplets have a low momentum and larger diameter and a narrower range of diameters so that the liquid droplets do not bounce off of a surface and/or the liquid droplets are more adapted to adhere to a surface.
The above and other objects, advantages and features of the invention will become more apparent when considered with the following specification and accompanying drawings wherein:
The operation of the different oscillators is disclosed in the aforementioned Raghu U.S. Pat. No. 6,253,782, Srinath et al U.S. Pat. No. 6,186,409, Stouffer U.S. Pat. No. 4,508,267 and Bray U.S. Pat. No. 4,463,904, all of which are incorporated herein by reference.
In each of the embodiments, the input hole or aperture is aligned with an input barb (not shown) on the housing. Referring now to
The multiple power nozzle has a pair of power nozzles P1, P2 which project a pair of fluid oscillator jets into the oscillation chamber OC and at least one outlet OL issues a pulsating or oscillating jet of liquid to a point of utilization on a surface or ambient. The two liquid jets or streams are properly sized and oriented in the oscillation chamber or interaction region OC such that the resulting flow pattern is a system of vortices that is inherently unstable and cause the two jets to cyclically change their direction. This produces a sweeping jet at the exit or outlet OL of the oscillation chamber OC.
In this embodiment, due to the fact that the power jet reverses its direction twice before exiting, the resulting spray will have relative low velocity. Thus, the requisite low velocity spray is developed while keeping a reasonable nozzle profile.
Referring now to
In
To recap, the invention provides large flow channels which decrease the possibility of clogging compared to restrictors. The droplets have low momentum, are of larger diameter, and are in a narrower range of diameters for similar operating pressure. The filter included with the reversing allows the nozzle to remain functional even if there are particulates in the flow while providing a flow path reverser. The invention allows for adequate flow rates for various purposes, such as rear window washing of cars under low-temperature environments. The invention provides controlled distribution of liquid and allows for delivering the liquid to the desired area without overspray or bouncing off the surface. The invention allows wide spray angles be designed to cover large areas without bouncing off the surfaces. Finally, the invention provides a solution of providing adequate flow rates and proper velocity of fluid sprays for certain unique situations such as described earlier herein.
While the invention has been described in relation to preferred embodiments of the invention, it will be appreciated that other embodiments, adaptations and modifications of the invention will be apparent to those skilled in the art.
This application is the subject of provisional application Ser. No. 60/256,470 filed Dec. 20, 2000 entitled GENERATION OF LOW IMPACT SPRAYS. This application is a continuation-in-part of application Ser. No. 09/417,899 filed Oct. 14, 1999 for FEEDBACK FREE FLUIDIC OSCILLATOR AND METHOD, now U.S. Pat. No. 6,253,782 and a continuation-in-part of application Ser. No. 09/457,316 filed Dec. 9, 1999, NOZZLES WITH INTEGRATED OR BUILT-IN FILTERS AND METHOD, now U.S. Pat. No. 6,186,409.
Number | Name | Date | Kind |
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3614961 | Nekrasov et al. | Oct 1971 | A |
4205786 | Babich et al. | Jun 1980 | A |
4463904 | Bray, Jr. | Aug 1984 | A |
4508267 | Stouffer | Apr 1985 | A |
6186409 | Srinath | Feb 2001 | B1 |
6253782 | Raghu | Jul 2001 | B1 |
Number | Date | Country | |
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60256470 | Dec 2000 | US |
Number | Date | Country | |
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Parent | 09417899 | Oct 1999 | US |
Child | 10016131 | US | |
Parent | 09457316 | Dec 1999 | US |
Child | 09417899 | US |