Spray Apparatus And Method

Abstract

A spray apparatus and method operable to concurrently discharge a spray product and air under pressure upon a surface. The air progressively atomizes the spray product upon discharge from an applicator to convert it into a fine, particulate, uniform spray. Air supply means provides air under pressure to a spray applicator as well as a spray product reservoir. Erratic air pressure fluctuation is not present in the reservoir. The air pressure requirement for the spray apparatus is relatively small. BACKGROUND OF THE INVENTION The invention relates to the field of liquid spray systems and in particular to those systems meant to provide a fine, particulate spray of a liquid and a gas, usually air under pressure. Such a system finds application, for example, in beauty salons where hair setting liquids and hair holding liquids and the like are in general use. While many of such liquids are available in aerosol cans, large scale use of aerosol cans is not economically feasible, and the use of such spray systems is preferred. One such spraying mechanism for use in beauty salons is described in U. S. Pat. No 3,122,324 to Lee. Other spray apparatus for various applications ar disclosed in U. S. Pat. No. 1,185,888 to Durham et al.; U. S. Pat. No, 2,743,134 to Smith; and U. S. Pat. No. 3,236,459 to McRitchie. These spray systems usually include a liquid or spray product reservoir for storing the spray product, and an applicator or spray means, such as a spray gun, associated with the reservoir to concurrently discharge air and the spray product on the surface to be srayed. Air supply means, usually an air compressor, supplies air or other gas under pressure to both the spray gun and the reservoir. For example, as shown in the patent to Durham et al, an air line extending from an air supply separates into two branches, the first branch supplying air under pressure to the reservoir, and a second branch to a spray nozzle. The first branch provides air pressure necessary in the reservoir to move the spray product out, while the second branch provides air under pressure at the nozzle to mix with and atomize the spray product as it is discharged. In the patent to Lee, an air line from an air supply terminates at the spray product reservoir. A second air line extends from the reservoir to a spray gun to provide it with the necessary pressurized air, whereby the reservoir actually constitutes a link in the passage of air from the air supply to the spray gun. In those spray systems of the prior art, as above described, the air supply means provides air under pressure simultaneously to the spray product reservoir and the spray gun. When the air supply line is opened, as by opening the spray nozzle, pressure in the air line drops. Air under pressure in the product reservoir, following a path of least resistance, leaves the reservoir through the inlet, flowing back into the now-lower pressure air line. When the air supply means is again operable to pressurize the system, air flows back into the product reservoir. Thus it may be seen that there is a continual flow of air into and out of the product reservoir, and the spray product in the reservoir experiences erratic pressure fluctuation. The amount and the pressure of spray product thereby delivered to the spray means necessarily fluctuates also. Liquids which are quick to evaporate, such as ether, are not susceptible of spraying in these conventional systems. With the air continually moving in and out of the reservoir, the product is quick to evaporate, saturating the air passing through the air line. In order to maintain an acceptably uniform, particulate spray at the spray nozzle, it is necessary, therefore, in the afore-mentioned spray systems, to use a relatively high air pressure as compared to that of the present invention. Due to the fluctuating supply and pressure of the spray product, if a low air pressure is utilized, the resultant spray is not fine and particulate as desired, but contains large globules of spray product. For example, the patent to Lee, when using the spray mechanism in beauty salon applications, suggests the use of an air pressure of 20 pounds per square inch. Thereby the ratio of the pressure fluctuation in the reservoir to the total pressure of the system is reduced to somewhat minimize the effect of the pressure fluctuations. Nonetheless, it would be desirable to entirely eliminate the pressure fluctuations in the reservoir, while at the same time operating a spray system at a relatively low air pressure. In addition, the product reservoir of the spraying mechanism of the patent to Lee includes a dip tube or a flexible tube extending from the top of the reservoir to the bottom, the product line being connected to the dip tube at the top. The use of such dip tubes in other systems is common. Such tubes are susceptible of malfunctioning through breakage or disconnecting or the like, as well as adding additional expense to the system. SUMMARY OF THE INVENTION The present invention provides a spray apparatus of the type described which provides a fine, uniform, particulate spray, while having a relatively low air pressure requirement. Air supply means supplies air under pressure through a main air line to a spray applicator, as a spray gun. A branch of the air line supplies air under pressure to a spray product reservoir. A spray product line extends from the reservoir to the spray gun. Disposed in the air branch to the reservoir is a one-way air valve orientated to permit the flow of air through the branch from the main air line to the reservoir, but operable to prevent the flow of air from the reservoir back into the main air line. Air thus entering the product reservoir from the main air line becomes dead or still air, and erratic pressure fluctuation due to rapid air movement is not experienced by the spray product in the reservoir, thus producing a dramatic improvement over spray systems of the prior art. The spray product is delivered through the product line to the spray gun at a uniform, even rate. At the spray gun nozzle, the spray product is concurrently discharged and atomized by air under pressure from the main air line, providing uniform, even and particulate spray heretofore unrealized by spray systems of the prior art. Yet the spray system of the invention accomplishes this result using a relatively low air pressure. For example, the present invention finds application in beauty salons, where the necessary air pressure is only 8 to 12 pounds per square inch for the spraying of hair treating products such as a hair holding product or a hair conditioning product. In terms of a method, the invention includes directing air under pressure through a main air line to a spray applicator; directing a portion of the air from the main air line through an air branch having a one-way air valve to a spray product reservoir; and directing the spray product from the reservoir through a product line to the spray applicator for concurrent discharge with air from the main air line through the applicator. An object of the invention is to provide a spray apparatus providing a fine, uniform, particulate spray of spray product. A second object of the invention is to provide such a spray system operable with a supply of relatively low pressure air. A further object of the invention is to provide such a spray system having a spray product reservoir not subject to erratic pressure fluctuations. Further objects of the invention become apparent upon the following description.

Description

IN THE DRAWINGS:

FIG. 1 presents a schematic view of the spray apparatus of the invention;

FIG. 2 is an enlarged sectional view of a one-way air valve as used in the spray apparatus of the invention;

FIG. 3 is a perspective view of a valve element as used in the air valve of FIG. 2; and

FIG. 4 is a fragmentary view of an alternative embodiment of a spray product reservoir of the spray apparatus of the invention with portions broken away for purposes of illustration.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIG. 1, there is shown schematically the various components of the spray apparatus of the invention, indicated at 10, in assembled relationship relative to one another. A product reservoir or container 11 is supported by a stand 12 on a surface 14, and is secured in place by appropriate strap 13. The container 11 contains the product to be sprayed, for example, a hair spray for use as a hair fixative by beauty salon operators. Container 11 has a lower necked-in portion 11a closed and sealed by a cap 15. One end of a spray product line 16, comprising a flexible hollow tubing, connects with an outlet of container 11 at cap 15 as by engaging a hollow pin or needle (not shown) inserted through the cap 15.

Spray means includes a spray applicator shown to be a spray gun 17 adapted to concurrently discharge a spray product and air under pressure upon a surface to be sprayed. Spray gun 17 includes a base or handle 19 and a forwardly projected barrel portion 20 terminating in an appropriate spray nozzle 21. The end portion of the barrel 20 defines a mixing chamber (not shown) for the mixing of spray product in air prior to discharge through the nozzle 21, whereby the expanding air mixes with and atomizes the spray product upon discharge, transforming it into a fine, particulate mist. A number of suitable types of spray guns or other types of applicators are commercially available. For example, a spray gun of the type disclosed by U. S. Pat. No. 3,122,324 to Lee, as shown in FIG. 1, has rendered satisfactory performance. A trigger 23 is pivotally mounted, as at 18, to the handle 19 of the gun. The product supply line and the end of an applicator air supply line 39 extend into the bottom of handle 19 upwardly to the barrel section 20. The upper end of trigger 23 is provided with a pair of fingers which respectively crimp or close the air and product lines. A spring 22 biases the trigger 23 in a normally closed position. Movement of the trigger 23 toward the handle 19 against the bias of spring 22 opens the air and product lines to allow concurrent discharge thereof.

Air supply means for supplying air under pressure to the spray apparatus is shown to include an air compressor 25 supported on a stand 26. Air compressor 25 is of a conventional, commercially available type having low power requirements and adapted to supply relatively low pressure. From the air discharge 27 of compressor 25 extends a first section 28 of a main air line 24, extending to a first T connector 29. The perpendicular leg of the connector 29 connects through a tubular branch 30 to an inlet 31 of an air pressure accumulator 32. The pressure accumulator 32 comprises a closed, empty container or vessel providing a sealed volume where air under pressure is accumulated for use when the air compressor 25 is shut off. The compressor 25 is equipped with a standard pressure switching mechanism whereby the compressor is energized when the line pressure drops to a predetermined level, and shuts off when the line pressure has been raised to a second predetermined level. By way of example, when the liquid product to be sprayed is a hair setting liquid as used by beauty operators, the compressor 25 is energized when the pressure in air line 28 drops to 8 pounds per square inch, and shuts off when the pressure in line 28 rises to 12 pounds per square inch. When, through the use of the spray gun 17, the pressure in air line 24 drops to 8 pounds per square inch, compressor 25 is energized to begin providing air under pressure to the spray apparatus. The compressor provides pressurized air to operate the spray gun and, at the same time, pressurizes accumulator 32. When the line pressure reaches 12 pounds per square inch, the compressor shuts off. The spray gun then receives air under pressure from that stored in the accumulator 32 until the line pressure again drops to 8 pounds per square inch.

A second section 34 of the main air supply line 24 extends from the first T connector to a second T connector 35. A connecting tube 33 extends from the perpendicular leg of the second T connector 35 to provide air under pressure from the main air supply line 24 to the container 11 and spray gun 17 of the spray apparatus. The main air supply line 24 continues from the second T connector 35, as at 36, where it may be extended to additional spray systems connected in series, as, for example, in a beauty salon where there may be a plurality of stations each having a separate spray product reservoir and spray applicator. If only a single spray applicator is used in the system, the main air line 24 is, of course, capped or otherwise closed at 36.

Connecting tube 33 extends from the second T connector 35 to the perpendicular leg of a third T connector 43. A reservoir inlet or container air pressure supply branch 37 extends from one of the aligned legs of the third T connector 43 to the product container 11. The end of the branch 37 opposite the third T connector 43 communicates with the interior of the container 11 as by engaging a tubular pin or needle (not shown) disposed generally in the upper portion of container 11 and opening into the interior thereof. Connected to the opposite aligned leg of the third T connector 43 is the applicator air supply line 39 which extends to the handle of the spray gun 17 as previously described. The third T connector as shown provides a reducing coupling allowing the use of a smaller diameter tubing for the branch 37 and supply line 39 than is used for the main air line 24. The use of smaller diameter tubing is preferable when a series of spray systems of the type shown receive air under pressure from a common air supply, whereby pressure drop along the main air line is minimized.

Intermediately disposed in the container pressure supply branch 37 is a one-way air valve 38. The valve 38 disposed in branch 37 accounts for the significantly improved performance of the spray apparatus of the present invention over those of the prior art. The valve 38 may be any one of several commercially available, the criteria being that the valve allow free air movement in one direction while restricting air movement in the opposite direction. In practice, a valve 38, as shown in detail in FIG. 2, has proven satisfactory. The valve 38 has a first tubular section 40 engaging a second tubular section 41. The second section 41 is provided with an end opening into which an end of the first section 40 snugly fits. The first and second sections together define a central tubular passage 42 for the passage of air. The enclosed end of the first section defines a cavity 44. A generally cylindrical, flexible rubber collapsible closure insert or valving member 45 has a shoulder 46 disposed between the outer edge of the first section 40 and an inner edge of the second section 41 of valve 38. As shown by FIG. 3, valving member 45 has a cylindrical wall extending forward from the shoulder 46. At the end of the member 45 opposite the shoulder 46, opposing side walls 46 converge and close, as at 48, thus closing the passage 42 of the valve 38. When air under pressure enters the valve through the end of the second section 41, as indicated by the arrow 49, the closure 48 yields under the air pressure and opens, allowing free passage of air. However, air entering the opposite end of the valve 38 is blocked at the closure 48, preventing passage of air in the opposite direction. The use of a valve having a soft, pliable rubber valving member, as the member 45, is preferable because of the quick closing and opening responses provided thereby.

As disposed in the container air passage branch 37, valve 38 is orientated to allow flow of air under pressure into the container 11 from the main air line 24, but operable to prevent air from flowing back through the branch 37 from the container 11.

In the use of the spray apparatus of the invention, spray product is stored in the container 11, as, for example, a hair holding spray. The compressor 25 pressurizes the spray system to a pressure of 12 pounds per square inch. The accumulator 32 and the upper or empty portion of the container 11 are also pressurized to 12 pounds per square inch. When the operator wishes to use the hair spray, he engages the trigger 23 of spray gun 19. Air and spray product are concurrently discharged from the nozzle 21, the air mixing with and atomizing the spray product to form a fine, particulate, uniform spray, as indicated at 51. While the spray gun is being used, air in the container 11 does not back up through the branch 37, whereby an erratic pressure fluctuation is not experienced by the spray product in the container. The spray 51 provided at the nozzle 21 is therefore fine and uniform. Additionally, since the spray apparatus is operated at a relatively low air pressure, the spray is gentle and easily controllable. Air pressure for the spray gun is provided by the accumulator 32. When the line pressure drops to 8 pounds per square inch, the air conpressor 25 is energized to re-pressurize the system.

The method of spraying a spray product includes providing a supply of air under pressure and directing it through a main air line to a spray applicator. A portion of the air is directed through an auxiliary branch having a one-way air valve to a spray product reservoir. Spray product from the reservoir is directed to the spray applicator for concurrent discharge therefrom along with the air.

It may thus be seen that the container 11, the inlet branch 37, and the outlet from the container 11 together comprise a reservoir system for the spray apparatus of the invention. For ease of manufacturing, if desired the spray reservoir system could be fashioned as an integral unit including a container with an inlet means and a one-way air-valve integral with the inlet means. The air valve could be built into the container, as in a recessed portion thereof, to be sheltered from damage or breakage. In such a configuration, the spray apparatus of the present invention would be adaptable for use in many existing spray systems.

An alternative embodiment of the spray product reservoir is illustrated in FIG. 4. A reservoir or container 55 holds the spray product and has a necked-in portion 56 at the bottom thereof. A plug 57 closes the container 55. A pair of hollow tubular pins or needle inserts 59 and 60 extend through the plug 57 from the exterior of the container 55 to the interior thereof. Spray product line 16 engages the outer end of the needle 59. The end of container pressure supply branch 37 engages the outer end of the needle 60. In such a configuration, the one-way air valve 38 not only prevents air movement and erratic pressure fluctuation in the container 55, but additionally prevents spray product from flowing into the air line 24.

While as shown and described, the spray apparatus of the invention employs a single spray product reservoir and a single spray applicator, there could as well be provided a plurality of spray applicators for use at a plurality of spray stations, as in a beauty salon. The several spray applicators could each be connected to a separate product reservoir, or all could be connected to a common reservoir.

Those skilled in the art will recognize that the present invention will find use in many applications other than beauty salons, where it is desirable to have a fine, particulate, low pressure spray. For example, the spraying of finishes, paints, cleaning fluids, insecticides, and the like. In the field of grinding lenses for eye glasses, before grinding, a lens is sprayed with a fine adhesive for attachment to a metal jig whereby the lens is held in place during grinding. The present spray apparatus satisfies the requirement of providing a fine, particulate spray of adhesive product under low pressure. The spray apparatus of the invention is particularly useful for the spraying of volatile products which would normally be quick to evaporate when exposed to rapid air movement and erratic pressure fluctuation. For example, the invention finds application in the medical field where it is common to spray ether on slight wounds for use as a local anesthetic.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An apparatus for the spraying of a spray product to obtain a fine particulate spray at low pressure comprising: a closed reservoir to contain the spray product; a main air line adapted to receive a supply of air under low pressure from an air supply means; spray applicator means operable to concurrently discharge air and a spray product in a fine particulate spray; said main air line connected directly to the spray applicator means to supply air under low pressure to the spray applicator means; an air pressure supply branch disposed between the main air line and the reservoir to supply air under pressure to the reservoir; a one-way air valve disposed in said air pressure supply branch orientated to allow the free passage of air from the main air line into the reservoir and restrict passage of air from the reservoir to the main air line; and a product line disposed between the reservoir and the spray applicator means to deliver spray product to the spray applicator means.

2. The spray apparatus of claim 1 including: a pressure accumulator disposed in said main air line.

3. The spray apparatus of claim 1 wherein: said spray applicator means comprises a spray gun.

4. The spray apparatus of claim 1 wherein: said one-way air valve includes a pliable, tubular, valving insert having collapsible closure means at one end.

5. The spray apparatus of claim 1 wherein: said air pressure supply branch connects with the upper portion of said reservoir.

6. The spray apparatus of claim 1 wherein: said air pressure supply branch connects with the lower portion of said reservoir.

7. The spray apparatus of claim 1 including: a plurality of said spray reservoirs associated with an equal plurality of spray applicator means; said main air line connected to each of said spray applicator means; an air pressure supply branch disposed between said main air line and each of said reservoirs; and a one-way air valve disposed in each said air pressure supply branch.

8. The spray apparatus of claim 1 wherein said spray apparatus is adapted for use in a beauty salon and including air supply means adapted to supply air to said main air line at a pressure between 8 pounds per square inch and 12 pounds per square inch.

9. In a spray apparatus of the type having a low pressure air supply means, a main air line extending from the air supply means directly to a spray applicator, and a spray product line extending to the spray applicator for the concurrent discharge of spray product and air under pressure, a spray reservoir system comprising: a closed container suitable to store a spray product; inlet means disposed on said container to admit air under pressure from said main air line; a one-way air valve integral with said inlet means orientated to allow the free passage of air from the main air line into the container and restrict passage of air from the container to the main air line; and outlet means integral with said container connected to said product line.

10. The spray reservoir system of claim 9 wherein: said inlet means is located on the upper portion of said container.

11. The spray reservoir system of claim 9 wherein: said inlet means is located on the lower portion of said container.

12. A method of spraying a spray product in a fine, particulate spray including the steps of: directing air under relatively low pressure through a main air line directly to a spray applicator; directing a portion of the air from the main air line through an air branch having a one-way air valve to a spray product reservoir; and directing the spray product from the reservoir through a product line to the spray applicator for concurrent discharge with air from the main air line through the applicator.

13. The method of claim 12 including the step of directing a portion of the air from the main air line to an air pressure accumulator.