Patent Grant
6905084
The present invention relates generally to sprayer assemblies, and more particularly to an airless application system with a tip cleaning function and a product container, and to a method of spraying using such a system.
Some aerosol products use a solvent to create a solution or suspension that includes the liquefied propellant. As environmental concerns have increased, aerosol products using water have become desirable. However, water does not mix easily with many propellant agents. In addition, film producing agents, such as adhesives, are designed with close tolerances with respect to miscibility and resistance to shear.
Most adhesives are made of synthetic polymers. In water-based adhesives, the polymer latex and resin dispersion constituents are suspended using surfactants. The surfactants have very specific functions within the system and are vulnerable to changes in temperature, shear, pH, and chemical contamination.
Adhesives are designed to create a film which is tacky and resistant to contaminants that may degrade the tacky characteristic. The film must not soften and release its hold on the substrate under varying conditions of exposure to heat, water, and solvents.
The same properties which are necessary in the adhesive are problematic in delivering the adhesive using an applicator. The surfaces of the application equipment, such as a spray gun, must remain free of adhesive build-up. If adhesive residue builds-up on the surfaces of the application equipment, the equipment may clog. The adhesive residue must then be removed manually by the user, which is time consuming and disruptive.
Most water-based adhesives are applied using air-assisted equipment. The application gun is designed with tandem valves so that both the air and product valves are open at the same time. The primary product is supplied to the gun from either a low-pressure container or through a venturi siphon and is atomized by a high-pressure stream of air. The compressed air helps keep the tip clean. However, air-assisted applicators are limited to locations where compressed air is available. In addition, they are prone to maintenance problems and the equipment can be difficult to adjust.
An airless solvent-based application system incorporates a needle valve to control the flow of the product to a tip designed to impart a particular pattern to the product as it exits the tip. In order to achieve this pattern, there is a space between the valve and the orifice. The space fills and swirls the product to obtain the spray pattern. When propellant is dissolved in the formula, the expansion in the tip space helps to clear the tip. However, for a simple-pressure pot system, there is no driving force to clear the tip when the valve is closed.
The use of water-based products in aerosol packages (that is, self-contained, pre-pressurized containers) is known. Formulations which require complete segregation from the propellants (such as “bag-in-can”) are also known. However, this technology has apparently not been used successfully for an adhesive and/or in a package larger than one liter.
Therefore, there is a need for an airless application system with a sprayer which can clear the sprayer tip after each application. There is also a need for an airless application system which uses a “bag-in-can” product container.
The present invention meets this need by providing an airless application system including a primary product container and a sprayer in fluid communication with the primary product container. The sprayer includes a sprayer tip; a primary product chamber for holding a primary product to be dispensed through the sprayer tip, the primary product chamber in selective fluid communication with the sprayer tip, the primary product chamber having an outlet; a secondary product chamber outlet in selective fluid communication with the sprayer tip; a manual control which travels through a range, the range including a first position and a second position; and a valve assembly responsive to the manual control, wherein when the manual control is in the first position, the primary product chamber outlet is closed; and wherein when the manual control is in the second position, the primary product outlet is open.
The primary product container may include a relatively rigid canister, a collapsible bag within the relatively rigid canister, the collapsible bag containing a primary product, a propellant in a space between the outside of the collapsible bag and the inside of the relatively rigid canister, and a valve connected to the relatively rigid canister, the valve comprising a primary product port in selective communication with the collapsible bag and a propellant port in selective communication with the space between the outside of the collapsible bag and the inside of the relatively rigid canister. The airless application system may optionally include a perforated tube sealed in the collapsible bag.
Alternatively, the primary product container can include a relatively rigid canister, a collapsible bag within the relatively rigid canister, the collapsible bag containing a propellant, a primary product in a space between the outside of the collapsible bag and the inside of the relatively rigid canister, and a valve connected to the relatively rigid canister, the valve comprising a primary product port in selective communication with the space between the outside of the collapsible bag and the inside of the relatively rigid canister and a propellant port in selective communication with the collapsible bag.
Another aspect of the invention is a method of airless spraying of a primary product and a secondary product.
As shown in
As shown in
Primary product 400 is contained within collapsible bag 110 positioned within canister 105. Bag 110 can be made of any material suitable for the separation and containment of primary product 400, including, but not limited to, plastics, such as polyethylene, polypropylene, and multilayer films, such as a polyethylene/nylon film, and metals, such as aluminum foils, and metallized films. The bag can be formed by welding two sheets of material together at the edges. Other methods of forming the bag could also be used, if desired. Typically, bag 110 is slightly oversized and shaped to conform to the inside of the canister 105.
Primary product 400 can be a material including, but not limited to, an adhesive. Generally, the adhesive is of a type which will flow at ambient temperature. Adhesives which flow at higher temperatures could also be used under appropriate high temperature conditions. The adhesive is generally a water-based adhesive, although solvent-based adhesives could also be used. Suitable adhesives include, but are not limited to contact adhesives and pressure sensitive adhesives.
Propellant 115 is charged between canister 105 and bag 110. Propellant 115 provides the differential pressure to drive primary product 400 out of bag 110 when the appropriate valves have been opened. Propellant 115 can be liquefied gases, compressed gases, or a combination, depending on the pressures desired and any regulations which might be involved. Suitable propellants include, but are not limited to, flammable and non-flammable liquefied or compressed gases. The propellant is generally charged to a pressure in the range of about 20 to about 500 psig, typically about 50 to about 200 psig, more typically about 80 to about 120 psig.
A cylinder valve 120 is threaded onto a receiving port 125 of canister 105. As shown in
The propellant port 135 can include a vertical propellant channel 155 and a horizontal propellant channel 160. There is a propellant valve 165 which controls the opening between the vertical propellant channel 155 and the horizontal propellant channel 160. One example of a suitable valve for propellant valve 165 is a spring-type valve, such as a Schrader valve. The space between the outside of the bag 110 and the inside of the canister 105 is filled with propellant 115 through the propellant port 135. If a Schrader valve is used, a needle in the clamp mechanism actuates the Schrader valve allowing the propellant to flow into the space between the outside of the bag 110 and the inside of the canister 105. Propellant can emptied from the space using the same valve.
The cylinder valve 120 can also include a pressure relief port 170. Pressure relief channel 175 is connected to vertical propellant channel 155 by pressure relief valve 172. One example of a suitable valve for pressure relief valve 172 is a spring-operated valve. The pressure relief valve 172 can have a pre-set pressure which will activate it.
Suitable valves for the primary product valve, the propellant valve, and the pressure relief valve are well known to those of skill in the art.
Cylinder valve 120 can incorporate a quick-release air fitting 180 to allow for easy installation and removal of bags 110. The primary product port 130 can have any suitable type of fitting, such as a National Pipe Swivel Mechanical (NPSM) fitting, so that it can be attached to an appropriate hose for connection to a sprayer.
Perforated tube 185 can be sealed or molded into bag 110 to act as a siphon for primary product 400. Perforated tube 185 can be integrated into one of the seams of bag 110, if desired. Perforated tube 185 allows unrestricted access to the top of the canister 105. Perforated tube 185 provides a path for primary product 400 to pass from bag 110 through the primary product port 130 of cylinder valve 120, through hose 190 and into primary product inlet 425 (see FIGS. 1 and 12). When the appropriate valves are opened, a differential pressure higher than atmospheric pressure allows the primary product 400 to exit the bag 110. As the bag 110 collapses, the propellant 115 expands to fill the area left vacant by the primary product 400.
The procedure for filling the primary product container involves introducing the primary product into the bag through the primary product port. The propellant port can be put under vacuum while the primary product is filled, if desired. After the bag has been filled with the desired amount of primary product, the primary product port can be cleaned to ensure that the primary product valve is free of primary product and closed. The propellant is filled through the propellant port, which is then closed. The primary product container is then ready for use. To ensure that the primary product container contains the appropriate amount of primary product and propellant, the filling can be done automatically using preset primary product and propellant weight set points. The entire fill process can be automated, if desired.
The primary product container can be reused after the primary product has been dispensed. The bag will likely need to be replaced, although it could also be reused in some situations, if desired. After the bag is placed in the canister and connected to the valve, primary product and propellant could then be charged into the primary product container as discussed above, and it would be ready for reuse.
Alternatively, the primary product and the propellant could be reversed in the container. In this arrangement, the propellant is contained in the collapsible bag while the primary product is in the space between the outside of the collapsible bag and the inside of the relatively rigid canister. The propellant would expand inside the bag, forcing the primary product out of the container. The bag would be designed to withstand the pressures involved. The valve has a primary product port in selective communication with the space between the outside of the collapsible bag and the inside of the relatively rigid canister and a propellant port in selective communication with the collapsible bag. The perforated tube would be placed into the space between the outside of the collapsible bag and the inside of the relatively rigid canister to allow flow of the primary product out of the space. The pressure relief valve would be in selective communication with the collapsible bag.
When the relatively rigid canister is made of plastic in this alternate arrangement, the use of a water-based primary product would not rust the canister.
When shaft 235 is in the forward position shown in
Chamber 220 is also in communication with passageway 265 and channel 270. Channel 270 is in communication with lateral channel 275 which is in communication with secondary lateral chamber 280. Secondary lateral chamber 280 is in selective communication with secondary product chamber 285. Secondary slider 290 reciprocates within secondary lateral chamber 280 controlling secondary product chamber outlet 295. When secondary product chamber outlet 295 is closed (see FIGS. 6-10), secondary slider 290 is seated against secondary seat 300.
Shaft 235 slides through the middle of secondary slider 290. Spring 297 biases secondary slider 290 toward secondary seat 300. However, when shaft 235 is in the position shown in
Secondary product chamber 285 includes tertiary chamber 305. Tertiary slider 310 reciprocates within tertiary chamber 305 controlling secondary product chamber inlet 315. When secondary product chamber inlet 315 is closed, tertiary slider 310 is seated against tertiary seat 320. Tertiary chamber 305 is in communication with pipe 325 via tertiary port 330. Tertiary port 330 receives secondary product 500 (for example, an aerosol-type cleaning solution) via pipe 325 which is in communication with chamber 335 in handle 340. Chamber 335 includes aperture 345 which is in communication with secondary product container 350 containing secondary product 500. Secondary product container 350 is contained within handle 340.
Shaft 235 slides through the middle of tertiary slider 310. Spring 355 in tertiary chamber 305 biases tertiary slider 310 to seat against tertiary seat 320, closing the secondary product chamber inlet 315.
Primary slider ring 269, secondary slider ring 299, and tertiary slider ring 359 are secured to shaft 235 so that they do not move relative to shaft 235. The movement of shaft 235 with primary, secondary, and tertiary slider rings 269, 299, and 359, in conjunction with the action of primary spring 267, secondary spring 297, and tertiary spring 355, causes primary slider 230, secondary slider 290, and tertiary slider 310 to move.
Trigger 360 is journaled to pivot about pivot point 365 on body 370 of sprayer 200. Trigger 360 includes boss 375 at a central upward location thereon which drives valve drive shaft 380. Valve drive shaft 380 is received within aperture 385 in body 370 and is biased by spring 390 within aperture 385 which urges valve drive shaft 380, in the absence of other forces (such as manual pressure by the user), to the position shown in
Valve drive shaft 380 is connected to shaft 235 so that shaft 235 moves in concert with valve drive shaft 380.
Therefore, when trigger 360 is slightly depressed (such as would happen when the user initially depresses trigger 360 but has not yet fully depressed it), shaft 235 moves from the position shown in
As trigger 360 is depressed further, shaft 235 moves to the position shown in FIG. 7. Secondary product chamber outlet 295 remains closed because secondary slider 290 is seated against secondary seat 300. Secondary product chamber inlet 315 remains closed because tertiary slider 310 is seated against tertiary seat 320. The movement of shaft 235 forces primary slider ring 269 against the back of cavity 277 in primary slider 230, causing primary slider 230 to move away from seat 260 and opening primary product chamber outlet 225. Primary product 400 flows around primary slider 230, into chamber 200, around shaft 235, and out through sprayer tip 210.
Primary product 400 also fills passageway 265 and channel 270. A check valve 273 is placed in channel 270 to prevent primary product 400 from being pushed into any other channels or chambers. The presence of check valve 273 adjacent to spray tip 210 minimizes the amount of secondary product, such as a cleaning solution, required to displace the primary product 400.
Trigger 360 is depressed further until it reaches the fully depressed position shown on FIG. 8. The shaft 235 has moved to the fully retracted position. Primary product chamber outlet 225 remains open because primary slider 230 is not seated against primary seat 260, and primary product 400 continues to flow from sprayer tip 210. Secondary product chamber outlet 295 remains closed because secondary slider 290 is seated against seat 300. Tertiary slider ring 359 forces tertiary slider 310 away from tertiary seat 320, opening secondary product chamber inlet 315. Secondary product 500 flows into secondary product chamber 285 and fills it because secondary product chamber outlet 295 is closed.
When the user is finished applying primary product 400, trigger 360 is released and shaft 235 moves forward to the position shown in FIG. 9. Primary product 400 is still flowing through the open primary product chamber outlet 225 to sprayer tip 210. Secondary product chamber outlet 295 remains closed. Tertiary slider ring 359 has moved forward sufficiently so that tertiary spring 355 forces tertiary slider 310 against tertiary seat 320, closing secondary product chamber inlet 315. With both secondary product chamber outlet 295 and secondary product chamber inlet 315 closed, secondary product chamber 285 contains a metered amount of secondary product 500.
As trigger 360 is released further, shaft 235 moves forward to the position shown in FIG. 10. Both secondary product chamber outlet 295 and secondary product chamber inlet 315 remain closed, and secondary product chamber 285 remains filled with secondary product 500. Primary slider ring 269 has moved forward in cavity 277 sufficiently that primary spring 267 forces primary slider 230 against primary seat 260, closing primary product chamber outlet 225 and stopping the flow of primary product 400.
As trigger 360 is released further, shaft 235 moves to the position in FIG. 11. Primary product chamber outlet 225 and secondary product chamber inlet 315 remain closed. Secondary slider ring 299 has moved forward so that it forces secondary slider 290 against secondary spring 297 and away from secondary seat 300, opening secondary product chamber outlet 295 and releasing the metered amount of secondary product 500 from secondary product chamber 285. Secondary product 500 flows through secondary lateral chamber 280 and lateral channel 275. It then flows through check valve 273, channel 270, passageway 265, channel 220, around shaft 235, and out through spray tip 210. If secondary product 500 is a cleaning solution, it will clean channel 270, passageway 265, channel 220, the exposed part of shaft 235, and spray tip 210, and help prevent the build-up of primary product 400, such as an adhesive.
An alternate embodiment of a sprayer 200 is shown in FIG. 12. Sprayer 200 includes sprayer tip 410 with aperture 415 therethrough for spraying or dispensing primary product 400 and secondary product 500. The sprayer 200 further includes primary product chamber 420. Primary product chamber 420 receives the primary product 400 from primary product inlet 425. Primary product inlet 425 would be connected to the primary product container 100. Primary product chamber outlet 430 is selectively opened and closed by slider 435 and shaft 440. Slider 435 includes needle 437. Shaft 440 is attached to slider 435, and slider 435 reciprocates within primary product chamber 420. When shaft 440 is in the forward position shown in
Secondary product 500 is introduced through secondary product chamber outlet 450. Secondary product chamber outlet 450 is selectively opened and closed by needle valve 455. When needle valve 455 is closed as shown in
The design allows the secondary product 500 to be injected along the side of the gun. The direction of flow is changed so that the check valve can be placed above the needle helping to evacuate latent adhesive behind the fluid tip.
The design also allows for easy assembly. By including annular channel 463, channel 460 and check valve channel 465 do not have to line up during assembly. As shown in
Trigger 470 is journaled to pivot about pivot point 475 on body 480 of sprayer 200. Trigger 470 includes boss 485 at a central upward location thereon which drives valve drive shaft 490. Valve drive shaft 490 is received within aperture 495 in body 480 and is biased by spring 497 within aperture 495 which urges valve drive shaft 490, in the absence of other forces (such as manual pressure by the user), to the position shown, wherein the primary product 400 is blocked from flowing by slider 435. Valve drive shaft 490 is connected to shaft 440 so that shaft 440 moves in concert with valve drive shaft 490.
When trigger 470 is depressed toward handle 498, shaft 440 withdraws slider 435 from seat 445 and needle 437 from opening 439, opening primary product chamber outlet 430. Primary product 400 flows through primary product chamber 420, around slider 435 and needle 437 and out through sprayer tip 410. When the trigger is released, slider 435 moves forward to seat against seat 445 and needle 437 enters opening 439, closing primary product chamber outlet 430.
With the primary product chamber outlet 430 closed, the valve of a container of secondary product (not shown) is contacted with needle valve 455. Needle valve 455 opens, allowing the secondary product 500 to flow through needle valve 455, into chamber 460, through annular channel 463, check valve channel 465, check valve 467, groove 469, and out through sprayer tip 410. Secondary product 500, such as a cleaning solution, cleans and wets everything it comes into contact with. Secondary product 500 can be under pressure, which allows the check valve 470 to open and remain open until the needle valve 455 is disengaged from the secondary product container.
Alternatively, a secondary product chamber could be connected to the secondary product chamber outlet with a valve used to control the secondary product chamber outlet.
The sprayer may optionally include a trigger guard 499 to prevent the sprayer from being activated accidentally.
Thus, the present invention provides a portable, self-contained supply of primary and secondary product. It allows an automatic tip-cleaning function if a cleaning solution is used as the secondary solution. The system is scalable, and mobility is only limited by the weight of the product and package. In addition, it can be used with a great range of products without the addition of ingredients that are environmentally or user unfriendly (volatile organic compounds, flammable, etc.).
While certain representative embodiments and details have been shown for purposes of illustrating the invention, it will be apparent to those skilled in the art that various changes in the compositions and methods disclosed herein may be made without departing from the scope of the invention, which is defined in the appended claims.
This application claims the benefit of U.S. Provisional Application No. 60/453,691 filed Aug. 22, 2002.
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| Number | Date | Country | |
|---|---|---|---|
| 20040050962 A1 | Mar 2004 | US |
| Number | Date | Country | |
|---|---|---|---|
| 60453691 | Aug 2002 | US |
