ES2386145T3 - Apparatus for spraying liquids, and disposable inner liners and containers for use with it - Google Patents

Abstract

Apparatus for spraying liquids, comprising: a fluid reservoir (12), a removable inner liner (13), which can be crushed, located inside the reservoir, said inner lining (13) having a base (13A) and side walls (138), and a spray nozzle (4) for distributing fluid from within the inner lining (13), characterized in that the inner lining (13) has a stable shape, in its non-crushed state, which corresponds to the inside of the tank (12) and is a tight fit within it, and wherein said inner liner (13) is crushed when fluid is removed from said liner during operation of the spraying apparatus.

Description

Apparatus for spraying liquids, and disposable inner liners and containers for use with it

The present invention relates to containers, more especially, disposable containers and containers that can function as inner liners. The invention also relates to apparatus for spraying liquids (for example, spray guns) and, more especially, to the containers or liquid tanks of such apparatus.

There are many uses, in many different technical fields, for disposable containers. For example, many goods are packaged in disposable containers (for example, bags) before or after purchase. When the disposable container is a plastic bag, the buyer will often reuse it as a disposable inner liner for another receptacle, for example a garbage can. In some cases, disposable inner liners are manufactured specifically for use in other reusable receptacles: in those cases, the inner liner may be intended to aid in the removal of the contents of the receptacle (as in the case of an inner liner in a bucket of The trash); to protect the receptacle or its contents; or to facilitate, or even eliminate, the cleaning of the receptacle.

The use of an inner liner in a receptacle in which a glue-like substance, paint

or plaster mixed or contained for use may be particularly advantageous, from the point of view of facilitating cleaning of the receptacle after use and preventing substances in the receptacle from being contaminated by the remains of other substances. Receptacles in which paints are mixed or contained for use, for example, must be clean to ensure that the color or quality of the paint is not altered by traces of other substances: this is particularly important, as explained previously, when a vehicle is being repainted and the paint is required to match the existing one. To avoid contamination problems when mixing paints, the implementation in vehicle repair shops is often to use disposable wax paper cups as mixing containers, particularly when only a small amount of paint is required. An alternative approach, proposed in US-A-4,383,635, involves the disposition of a disposable container which, for use, is located in a reusable receptacle similar to a frame.

In the technical field of spray guns, it has been proposed, for various reasons, that a disposable inner liner should be used in the gun tank (see US-A-3,211,324, 3,255,972, 4,151,929 , 4,951,875, 3,432.1O4 and 5,143,294, and EP-AO 678 334). Generally, guns for spraying liquids (eg, paints, garden chemicals, etc.) are well known and typically comprise a reservoir in which a liquid to be distributed is contained, and a spray nozzle through which it is distributes the liquid, under pressure, under the control of a trigger mechanism. The liquid can be fed from the tank by gravity and / or it can be carried in a stream of pressurized fluid, for example air or water, which is supplied to the gun from an external source.

When a user wishes to change the liquid in the tank of a spray gun, it is usually necessary to clean the gun very thoroughly to ensure that no trace of the old liquid that contaminates the new liquid is kept in the gun. This applies particularly to paint spray guns since any trace of an old dose of paint held in a gun can affect the color of a new paint dose, to the point that the new paint dose becomes useless. This can cause problems especially in repair shops for vehicles where it is often required that the paint applied to a vehicle exactly matches the existing paint. Alternatively, if paint residues have been allowed to dry inside the gun, they can peel and contaminate the new paint dose. Cleaning spray guns is, however, a relatively complex and time-consuming operation. In addition, in the case of paint spray guns, the cleaning operation involves the use of relatively large amounts of solvents that, for environmental reasons, should be handled and disposed of carefully. This, in turn, can be substantially added to the cost of a painting operation. It has already been suggested (see, for example, EP-AO 678 334 mentioned above) that the use of a disposable inner liner in the paint tank (ie, the paint can) of a spray gun can simplify cleaning of the gun and reduce the required amount of solvent.

The present invention relates to the arrangement of a container that is economical enough to be disposable and which can preferably be crushed when it is to be disposed of but which, however, is relatively easy to handle and fill when used. The invention relates, more especially, to the arrangement of such a container, which is suitable for use as an inner liner in another receptacle. The present invention also relates to allowing the cleaning of spray guns and similar devices to be simplified, and thereby allowing the time and expenses associated with said operation to be reduced.

The present invention describes a container, comprising side walls and a relatively rigid thermoformed / vacuum formed base from a plastic material; in which the side walls are thin compared to the base and can be crushed, but the container is capable of being straight, without support, on the base with the extended and vertical side walls.

More especially, the present invention describes a container, comprising a base, and side walls extending from the base; wherein the base and the side walls are thermoformed / formed by vacuum together from a plastic material, such that the base is relatively rigid and the side walls are thin compared to the base and can be crushed, but the container is able to be straight, without support, on the base with extended and vertical side walls.

A container according to the invention can be used as an inner liner for a receptacle, said liner having a shape that corresponds to the inside of the receptacle. As a modification, the invention also describes, in combination with a receptacle, a disposable inner liner that fits inside the receptacle and has a shape corresponding to the interior thereof, in which said liner is thermoformed / vacuum formed from a plastic material . The inner lining can be preferably crushed, but not necessarily.

The present invention also describes a spray gun, comprising a fluid reservoir; a removable inner liner, which can be crushed, having a shape corresponding to the inside of the tank, and is a tight fit within it, and a spray nozzle for distributing fluid from inside the inner liner, in which said liner is crushed when fluid is removed from the inside during gun operation.

Also, in accordance with the invention, a spray gun is provided, comprising a fluid reservoir having a removable cover located in an opening in the tank; a removable inner lining located inside the tank and secured thereto, by the cover, on the periphery of the opening; and a spray nozzle for distributing fluid from within the inner lining; wherein said coating can be removed from the tank together with the lid.

The present invention also describes a gravity-fed spray gun, comprising a fluid reservoir having a removable cap located in an opening thereof, and a spray nozzle for distributing fluid extracted from within the reservoir through an outlet in the cap ; wherein said deposit can be disassembled from the gun and is capable of being straight on its own to allow fluid to be loaded into the tank through the opening.

The invention further describes a spray gun, comprising a fluid reservoir; and a spray nozzle for distributing fluid from within the reservoir; the deposit comprising a self-supporting container that can be disassembled from the gun and which can be crushed for disposal.

According to another aspect of the invention, a fluid reservoir for fixing to a spray gun is provided, said reservoir having a removable cover that is located in a tank opening and in which a fluid outlet for the tank is formed. ; the deposit including a removable inner liner, which can be crushed, which has a shape corresponding to the deposit, and is a tight fit within it; wherein said lining is secured to the tank by the lid on the periphery of the opening and can be removed from the tank together with the lid. The invention also describes a fluid reservoir for attachment to a spray gun, said reservoir having a removable cap that is located in a tank opening and in which a fluid outlet for the reservoir is formed, the fluid outlet for fixation to the spray gun; and an air discharge, which can be closed, at the end of the tank, away from the lid.

In accordance with a further aspect of the invention, an inner liner is provided for use in the deposition of a spray gun, said liner being formed from a plastic material and a tight fit within the reservoir; the inner lining having a relatively rigid base, and side walls that are thin compared to the base and that can be crushed.

The present invention also describes a spray gun, comprising a fluid reservoir, and a spray nozzle for distributing fluid from within the reservoir, said reservoir having a removable cap and including a removable, generally conical grid filter, secured in the reservoir by the lid

The present invention also describes a gravity-fed spray gun, comprising a fluid reservoir, and a spray nozzle for distributing fluid from within the reservoir, said reservoir having a removable lid and a removable inner liner secured in the reservoir by the lid.

The term "vacuum thermoforming / forming", as used herein, means a process by which a sheet of material is heated to a softened state and shaped into a required shape, defined by a mold, while in said softened state. It includes the case in which the application of a differential air pressure is used to help shape the material in the required manner and, in particular, it includes the case where vacuum occurs on one side of the material to help shape it in the required form (also known simply as "vacuum forming").

The expression "that can be crushed", as used herein with reference to the side walls of a container / inner liner according to the invention, indicates that the side walls may be

distorted so that, by the application of moderate pressure (for example, manual pressure), the flange of the

container can be pushed towards the base of the container, without breaking said walls. The term "paint" is used herein to include all forms of coating material to paint mode that can be applied to a surface using a spray gun, whether or not intended for Color the surface. The term includes, for example, primers, basecoats, varnishes and similar materials.

By way of example only, embodiments of the invention will be described with reference to the drawings that are

they accompany, in which: Figure 1 is a perspective view of a spray gun of the prior art, shown partially disassembled, so that it can be filled with paint;

Figure 2 shows the components of an alternative form of paint deposit for the gun of the

Figure 1, in an exploded state; Figure 3 shows the paint tank of Figure 2, in an assembled state, with an adapter for connect said tank to a spray gun;

Figure 4 shows a longitudinal cross section through the paint tank and the adapter figure 3; Figure 5 shows the paint tank of Figure 4 when attached to a spray gun;

Figure 6 shows the paint tank of Figure 4 when used on a spray gun; Figure 7 shows components of the paint tank of Figure 4 that are disassembled after their use;

Figure 8 is similar to Figure 2, but shows a modified form of paint deposit;

Figure 9 shows a longitudinal cross section through an alternative cover form for the paint deposits of figures 2 to 4, and 8; Figure 1O is similar to Figure 2, but shows another modified form of paint deposit; Figure 11 shows part of a longitudinal cross-section through the paint deposit of the

figure 1O;

Figure 12 shows a spray gun similar to that of Figure 1, but with an alternative form of paint deposit; Figure 13 shows the gun of Figure 12 with a modified form of paint deposit; Figure 14 illustrates a modification of the gun deposit of Figure 13; Figure 15 is a view, similar to Figure 3, of an alternative form of paint deposit; Figures 16 and 17 show modified forms of a component of Figure 15; Figure 18 illustrates the use of a support for the paint deposit of Figure 15; Figure 19 is a perspective view of an inner liner / container according to the invention; Fig. 2O is a similar view, but showing the inner liner / container as being

crushed for disposal;

Figures 21 (a) to 21 (c) are diagrammatic illustrations of a method for manufacturing an inner liner for the paint deposits of figures 2 to 4, and 1O; Figure 22 illustrates a modification of the method of Figure 21; Figure 23 shows a graduated jug of paint mixture; Y Figure 24 shows an inner liner according to the invention, for use with the jar

Graduated from Figure 23. Figure 1 of the drawings illustrates a typical prior art paint spray gun 1 of the gravity fed type. The gun 1 comprises a body 2, a handle 3 extending downwardly from the rear end of the body, and a spray nozzle 4 at the front end of the body. The gun is

manually operated by a trigger 5 that is pivotally mounted on the sides of it. The paint tank, or paint can, 6 containing paint (or similar material) to be discharged by the gun, is located on the upper part of the body 2 and is in communication with an internal passage passage (not visible) for air compressed, which extends through the gun from a connector 7 at the lower end of the handle 3 to the nozzle 4. When used, the connector 7 is connected to a source of compressed air (not shown) so that, when the user presses the trigger 5, compressed air is supplied through the gun to the nozzle 4 and drags and atomizes paint that is being supplied by gravity from the canister 6. The paint is then discharged through the nozzle 4 with compressed air, as a pulverized substance.

The paint that is contained in the canister 6 is often mixed by hand (for which an independent receptacle, for example a jug is required), and is poured into the canister. To ensure that there are no unwanted particles in the paint, which would deteriorate the finish of the painted surface, the paint is usually poured into the canister 6 through a filter. Figure 1 shows the lid 8 of the canister 6 removed for this purpose, and a conical filter 9 about to be located at the open end of the canister. The filter 9 is shown as being a known type of disposable conical filter, having solid sides and a portion of filter mesh 1O at the pointed end of the cone. When the canister 6 has been filled with paint, the filter 9 is disassembled and discarded, and the canister lid 8 is replaced. If the filter 9 is a reusable filter, then, similar to the gun, it should be thoroughly cleaned before it is used with a different liquid (for example, a paint of a different color or a liquid that has a different chemical composition) .

Figure 2 illustrates the components of an alternative form of paint can 11 that can be used with the gun 1 of Figure 1 (or any similar gun) instead of the canister 6. The alternative form of paint can 11 is shown mounted in figure 3 and (in cross section) in figure 4.

The paint can 11 comprises an open container 12, comparable in size to a usual paint can of a hand spray gun, which has a hole 12A for air at its base and provided with a disposable inner liner 13. The inner lining 13 corresponds in shape to the inside (and is a tight fit therein) of the container 12 and has a narrow flange 14 at the open end that sits on the upper edge of said container. The container 12 also has a disposable lid 15 which is a push fit at the open end of the inner liner 13. The lid 15 has a central opening 16 (Figure 4) from which a connector tube 17 provided, at its end, extends. , of outward extensions 18 that form a part of a bayonet connection. The opening 16 is covered by a filter mesh 19 that can be adjusted by pushing into the opening or can be an integral part of the lid 15. The lid 15 is held firmly in place on the container 12 by an annular collar 2O which it is screwed into said container, on top of said lid.

The paint can 11 is fixed to the spray gun 1 thanks to the use of an adapter 21 shown, separated from the paint can, in figure 3 and (in cross section) in figure 4. The adapter 21 is a tubular component which, at one end 22, is formed internally with the other part of the bayonet connection for attachment to the connector tube 17 of the paint can 11. At the other end 23, the adapter is shaped to match the standard fixing element of the paint can of the spray gun (typically a screw thread).

The inner lining 13 of the paint can 11, as already mentioned, corresponds in shape to the inside of the container 12 and has a narrow flange 14 at the open end that sits on the upper edge of the container. As described below, the inner liner is self-supporting, but it can also be crushed and, preferably, has a relatively rigid base 13A and relatively thin side walls 138 so that, when crushed, it is in the longitudinal direction in which it is crushed, by the side walls, instead of the base. In addition, the inner lining 13 does not have creases, corrugations, seams, connections or reinforcements, and neither grooves in the internal connection of the side walls 138 with the base 13A. Such an inner liner will be described in more detail below with reference to Figures 19 and 2O. A thermoforming process, by which such inner lining can be manufactured, is also described below.

The container 12 of the paint can 11 is formed from a plastic material, for example polyethylene or polypropylene, and can be translucent (as shown in Figure 2) or opaque, and of any suitable size. For use with a paint spray gun, containers that typically have a capacity of 25O, 5OO or 8OO ml could be used, although other sizes could be used, if required. The cover 15 is also formed from a plastic material, for example, polyethylene or polypropylene, and may be formed by an injection molding process. The lid may be translucent or opaque and may be colored. The collar 2O can be a molded plastic component, or it can be a machined metal component (eg aluminum). The adapter 21 can be a machined metal component and can be shaped, for example, from aluminum and be anodized.

To use the paint can 11, the adapter 21 is fixed (at the end 23) to the spray gun and left in position. Then, with the paint can 11 removed as shown in Figure 2, the inner liner 13 is pushed into the container 12. Then, the paint is introduced into the container, the lid 15

it is pushed into place and the collar 2O is fixed with screws tightly to keep the lid in position. The upper portion of the inner liner 13 is then trapped between the lid 15 and the container 12, and the flange 14 of the inner liner is caught between the upper edge of the container and the collar 2O, as shown in Figure 4. Advantageously, the cover 15 is formed with protruding elements (not visible) on its surface to be applied to the upper part of the inner lining and hold it. The spray gun 1 is then reversed from its normal operating position so that the end of the connector tube 17 can be fixed to the adapter 21, as illustrated in Figure 5, after which the gun can be returned to its position. normal (illustrated in Figure 6) and is available for use in the usual way. As the paint is removed from within the inner liner 13, the sides of said liner are crushed as a result of the lower pressure within the inner liner. The base of the inner lining, being more rigid, retains its shape so that the inner lining tends to crush in the longitudinal direction rather than the transverse one, thereby reducing the possibility of trapped paint pockets remaining in the inner lining. .

The user can choose to evacuate the air from inside the inner liner 13 before operating the spray gun 1, although this is not essential. However, the range of angles in which the gun will operate satisfactorily is increased, since there is no risk of air entering the gun from the paint can

11. To evacuate the air from inside the inner liner 13, the trigger 5 of the gun should be operated while it is still in the position shown in Figure 5.

After use, when the gun is to be cleaned, the gun can be reversed again and the trigger 5 can be operated briefly to allow the paint inside the gun to drain back into the inner liner in the canister 11 The canister 11 is disassembled from the gun then separating the connector tube 17 from the adapter 21 (which is held on the gun). The collar 2O is removed from the container 12, and then the lid 15 is removed, carrying with it the crushed inner liner 13, as shown in Figure 7. The lid (including the filter 19) and the inner liner are discarded, leaving container 12 and collar 2O clean and prepared for reuse with a new inner liner and lid. Only the gun itself has to be cleaned, resulting in a substantial reduction in the amount of solvent used. The risk of spillage of unused paint from the canister 11 is also substantially reduced, since the inner liner 13 is removed and discarded with the lid 15 in place. In addition, since the inner liner is discarded in a crushed state, the amount of space required to collect used inner liners is minimized.

Since the inner lining 13, as described above, is a precise fit within the container 12 and has a uniform internal surface, it is possible to mix paint in the container 12 itself rather than in a separate receptacle. In this way, cleaning of an independent mixing receptacle can be eliminated to achieve a further reduction in the amount of solvent used. This possibility does not exist when a gravity-fed gun with a usual paint can is used, as shown in 6 in Figure 1, since the latter is open at both ends. The possibility that the mixing tool punctures or damages the inner lining 13 is minimized, firstly since the inner lining fits within the container 12 accurately and, secondly, since the self-supporting nature of the inner lining (described in continued) means that it is less likely to be dragged spinning inside the container during the mixing process. To facilitate the use of the container 12 as a mixing receptacle, the side walls of the container may be provided with marks 25 (Figures 2 and 3), which allows determining the volume of the contents of said container. The general shape of the container 12 and, in particular, the fact that it is flat and stable when it is in the orientation shown in Figure 2, makes it particularly suitable for use as a mixing receptacle, such as the fact that it is translucent as already described. If, however, the container 12 is opaque, it could be formed with grooves in the side walls, through which the inner lining 13 could be seen to allow the user of the spray gun to evaluate the amount of paint in the Boat 11 at all times.

When paint is mixed in the container 12, the inclusion of the filter mesh 19 in the lid 15 of the container prevents unwanted particles in the paint from entering the spray gun. The mesh 19 can be omitted, however, if the paint is textured, or if it is mixed in a separate receptacle and filtered when it is transferred to the coated container 12 or if the presence of impurities in the paint is not important.

Although the collar 2O of the paint can 11 has been described above as being an independent article, it could be combined with the cap 15, in which case it would also be disposable. As an additional alternative, the cover 15 (with the connecting tube 17 and the mesh 19) could be formed as an integral part of the inner lining 13, to which it could be connected by an articulated connection 26, as illustrated in Figure 8. In that case, there is no need for the lid to fit inside the mouth of the inner liner to ensure that the lid and inner liner are disassembled together from the container after use: however, that would still be necessary if required. that the lid remains in place in the inner liner after use. As a further alternative, the collar 2O could be replaced by a band secured around the top of the boat 11 to keep the lid 15 and the inner liner 13 in place. The band could be secured by

canister 11 and could be formed, for example, from rubber or be part of a firm metal fastening arrangement of the type used to secure the upper parts of jars and bottles.

If a more positive application is required between the lid 15 of Figures 2 to 4 and the inner liner 13, the lid could be an elastic jump adjustment with the inner liner, rather than a push fit, as shown. The inner lining could be shaped, for example, with an inner circumferential rib located to be applied in a corresponding groove on the adjacent surface of the lid.

As a further alternative, the inward push cover 15 could be replaced by a cover 27 with the shape shown in Figure 9. The cover 27 is also a push fit within the inner liner, but is generally conical and in shape. its upper end 28, corresponds in shape with the end of the connecting tube 17 of Figures 2 to 4, so that it will be applied on the same adapter 21. The cover 27 has an outwardly extending flange 29 that will sit on the upper part of the flange 14 of the inner liner, and a shaped portion 29A that will be applied to the inner surface of the inner liner. The shape of the shaped portion 29A allows the lid 27 to be pushed into the mouth of the inner liner and also provides a recess 298 in which the edge of the inner liner can be contracted so that the lid is securely located. The shape of the shaped portion, illustrated in Figure 9, is not essential, however, and alternatives could be used that include, for example, protruding elements, as described above with reference to the cover 15 of Figure 4. The lid 27 is held in place on the container by a threaded collar, similar to the collar 2O, which will sit on the top of the flange 29 of the lid. The cover 27 can incorporate a filter similar to the filter 19 of Figures 2 to 5. Alternatively, in each case, the filter can generally have a cylindrical shape so that it can be inserted into the tubular part of the cover from the end adjacent to the bayonet connection. In that case, the internal shaped element of the tubular part of the lid should ensure that the filter is held in position when the spray gun is being used.

The components of an alternative form of paint can 3O are illustrated in Figure 1O. The canister 3O, similar to the canister 11 of Figure 2, comprises a container 12 and an inner liner 13. In this case, however, the canister 19 of the canister 11 is formed as an independent article 31 having a diameter corresponding to that of the container 12 and which includes a circumferential sealing gasket 32. In addition, the lid 15 and collar 2O of the canister of Figure 2 are replaced by a generally conical lid 33 which is a threaded fit in the container and which, at its end upper has a tubular extension 34 similar to the connector tube 17 of Figure 3, so that it will be applied to the same adapter 21. The canister 3O is mounted by pushing the inner liner 13 into the container 12 and then after paint has been introduced into the container, placing the filter 31 on the top of the container and securing it in position by fixing with screws of the lid 33. The flange 14 of the inner lining 13 and the sealing gasket 32 of the filter 31 are then both trapped between the lid 33 and the container 12, as illustrated in Figure 11, thus preventing paint leakage from the canister 3O in this position when the canister has been secured to A spray gun is inverted for use.

The adapter 21 could be dispensed with by forming the ends of the tubular parts 17, 34 of the lids of the containers 11, 3O with screw threads so that they can be applied directly to the fixing element of the standard paint can on the spray gun one.

Figure 12 illustrates an alternative spray gun in which the standard paint can 6 of the spray gun 1 (see Figure 1) is retained and is provided with an inner liner 35 that fits inside the can and extends, preferably, towards within the connection with the gun body 2 to form a liquid-tight seal with the latter, for example thanks to the use of a flexible (not visible) o-ring between the gun and the inner liner. In this case, the inner liner 35 does not crush when the paint is removed from inside the can and can be formed from a more rigid material to aid its positioning inside the canister 6. Once in position, the liner interior 35 is held in place by the cover 8 which is fixed with screws on a flange 36 extending outwardly at the open end of the inner lining. The canister 6 of Figure 12 is additionally provided with a filter 37 which is generally conical in shape and is completely formed of mesh material and which, when used, is located inside the inner liner 35. The filter 37, similar to the inner liner 35, has a flange 38 that extends outwardly which is located on the upper part of the flange 36 of the inner liner and is also held in place by the lid 8 of the canister 6.

The canister 6 of Fig. 12, unlike the canister 11 of Fig. 3, is intended to be filled with paint while it is fixed to the spray gun 1. The inner liner 35 and the filter 37 are placed in position, paint is poured in the boat, and the lid fits. During this operation, there is no risk that the filter will be dislodged and, since the filter is formed entirely of mesh material, the user can always see the level of the paint while it is being poured into the can. The gun 1 is then available for use. All the paint that distributes the gun passes through the filter 37 and there is no need, therefore, for the paint to be filtered when it is being poured into the canister 6. After use, the cover 8 is unscrewed to allow disassembly of the filter 37 and the inner liner 35. The inner liner 35 is discarded and the filter 37 is also discarded or cleaned, depending on whether or not it is disposable. The use of the inner lining 35 reduces

again the amount of solvent required to clean the gun 1, an additional reduction being possible thanks to the use of a disposable filter 37.

The filter 37 may have any suitable shape and may have, for example, grooved sides to increase the effective surface area of the filter.

In a modified arrangement, illustrated in Figure 13, the inner liner 35 and the filter 37 are combined to form a single unit 39. In this case, the filter is discarded with the inner liner.

In each of the arrangements shown in Figures 12 and 13, the inner liner 35 and the filter 37 can be removed from the canister 6 with the lid 8. In that case, it is possible to replace the usual lid 8 of the canister 6 with a lid disposable, so that the lid 8, the inner lining 35 and the filter 37 can be discarded together.

The disposable unit 39 of Figure 13 could be modified so that the paint can 6 of the spray gun 1 was replaced, instead of being fitted inside the paint can. In that case, the unit 39 could be supplied as a sealed cartridge 5O already filled with paint as illustrated in Figure 14. Externally, the cartridge 5O is similar to the paint can 6 and can be connected to the gun 1 in the same way . Since it is sealed, however, the outlet end 51 of the cartridge must be perforated and an air discharge arranged, for example at the other end 52 of the cartridge, to allow the paint to enter the gun. The user could pierce, for example, the outlet end 51 of the cartridge 5O before the cartridge (with the highest outlet end) is fixed to the gun (inverted). Alternatively, the gun 1 could be modified so that the outlet end 51 is automatically pierced when the cartridge 5O is fixed to the gun. An air discharge could then be formed at the other end 52 of the cartridge 5O after having fixed the cartridge to the gun by manually piercing said end of the cartridge or, for example, fixing an independent cover 53 that is designed to pierce the cartridge when It is placed in position. Alternatively, an air discharge, which simply has to be opened when the gun is available for use, could be preformed in the cartridge.

After use, the 5O cartridge is removed from the gun and discarded. Since the 5O cartridge contains a filter, there is no need for the supplier to filter the paint before it is loaded into the cartridge. If, however, the paint is prefiltered, then the filter in the 5O cartridge can be omitted.

Figure 15 illustrates an alternative form of paint can 4O for a spray gun 1, which is completely disposable. The paint can 4O is generally similar to the can 3O shown in Figure 1O except that the container 12 is replaced by a disposable container 41, described below, and the inner liner 13 is omitted.

The container 41 of Figure 15 can be any usual disposable container suitable for holding paint and for attachment to the lid 42 of the paint can. The container 41 may be shaped, for example, from a thin, preferably translucent plastic material (as shown), so that the contents of the container are visible and preferably have marks 43 on the side walls to allow the determination of the volume of the contents of the container. An air hole 44 is formed in the base of the container, along with some means to close the air hole when desired. Said means may be in the form of a strip of adhesive tape (not shown) that is detached again to open the hole 44 and can be re-adhered to close the hole when required. Alternatively, a top closure can be provided that is removed at once

or some simple manually operated valve mechanism. The container 41 has an external screw thread at its open end, for fixing the lid 42, which is generally similar to the lid 33 of Figure 1O and is also shaped, at its upper end 42A, for fixing to a spray gun (if necessary by means of a suitable adapter). The lid 42 may be formed from the same material as the container 41 and, as shown, may also be translucent. A flat filter mesh 45, which is also disposable, extends through the mouth of the container 41. The mesh 45 may be an independent article, which is maintained at its periphery between the lid 42 and the container 41, or it may be formed integrally with the lid.

To use the canister 4O, the lid 42 and the filter mesh 45 are removed from the container 41 which is then filled with paint (taking care that the hole 44 for the air in the base of the container is closed). It is not necessary to filter the paint when it is introduced into the container 41 and, as described above, it is possible to mix the paint in the container, thereby avoiding the need for an independent receptacle with that objective. The lid 42 and the mesh 45 are then put back into position on the container 41, the lid 42 is fixed to the spray gun (inverted) 1 which is then returned to its normal position, and the hole 44 is opened for the air in the base of the container. Spray gun 1 can now be used as usual. At the end of the spraying operation, the air hole 44 is closed again, the canister 4O is separated from the gun 1 and can then be discarded leaving only the gun to be cleaned. Before the canister 4O is separated, the spray gun 1 can be reverted and the trigger 5 of the gun actuated to allow the excess paint held in the gun to drain back into the canister. In any case, if enough paint is kept in the 4O canister, that can be resealed (instead of being discarded) and used again.

Advantageously, the container 41 of the canister is shaped so that it can be crushed after use. In some cases, it may be possible that the lid 42 can also be crushed.

Alternatively, the cover 42 could be a reusable component and would be cleaned together with the gun. With such an arrangement, it is possible that the disposable container 41 is supplied as a cartridge already filled with paint and sealed by a cover that would simply be removed before attaching the container to the lid 42. The filter mesh 45 could be a component disposable or reusable one. As an additional alternative, the container 41 and the cover 42 could be supplied together as a sealed cartridge by a removable cover, at the upper end 42A of the lid, which would be disassembled before attaching the cartridge to the gun. In that way, the cartridge is similar to the cartridge 5O of Figure 14.

Through an appropriate selection of the dimensions of the lid 42 of the paint can 4O, it is possible to use a single lid 42 with containers 41 of different sizes. The user would then select, in each case, the container 41 containing the most suitable amount of paint. It may also be desirable to provide a range of filters 45 that have different mesh sizes so that the user can select the mesh size that is most suitable for the type of paint being used. It is not essential that the filter mesh 45 has the shape and / or position shown in Figure 15: it could, for example, have a conical shape, as shown in Figure 16, and / or could be located at the outlet of The lid 42, as shown in Figure 17. Alternatively, the filter 45 can be omitted if the paint is filtered before it is introduced into the container 41, or if the presence of impurities in the paint is not important.

The cover 42 does not have to have the exact shape shown in Figure 15 and could be replaced, for example, by a push-in cover in combination with a threaded collar, as shown in Figure 2.

When the container 41 (with or without the lid 42) is supplied as a cartridge containing paint (or other coating material) it may be desirable, in some cases, for the paint / coating material to be contained in a sealed inner liner, that can be crushed inside the cartridge. This may be desirable, for example, if it is necessary to keep the paint / coating material isolated, for example from air or light, until they have been sprayed onto the surface to be coated. The hole 44 for the air in the container 41 can then be kept open all the time, or it can be omitted if the container 41 itself is not airtight.

Depending on the shape of the container 41, it may be desirable to provide a support on which the container can be placed to ensure that it does not tip over. A suitable support 5O, shown in Figure 18, comprises a portion 51 of the container that is similar in shape to container 41, but is slightly larger than it, and is provided with an enlarged base 52. The container 41 is placed in the part 51 of the container to ensure that it remains vertical while it is being filled and / or fixed to the spray gun 1.

Although the above description refers to a paint spray gun, it should be understood that it also applies to other types of spray guns including, for example, guns of the type that are attached to flexible water pipes (rather than to supply pipes of air) to spray substances such as garden chemicals. The description also applies to aspiration-fed guns, that is, guns in which the liquid outlet from the tank is located at the top of the tank when the gun is being used and liquid is removed from the tank through a tube of supply by the action of compressed air or other pressurized fluid circulating through the gun. In that case, when the deposit is provided with an inner liner, the construction of the inner liner and / or the supply tube should be such that the inner liner can be crushed without blocking the supply tube. For example, a short supply tube can be used as long as all air is removed from the inner liner before using the gun. Alternatively, a flexible supply tube could be used, which would crush with the inner lining. As an additional alternative, a modified inner liner that does not have a rigid base could be used, so that the inner liner is crushed differently than the inner liner 13 of Figure 2. Since the deposit of a suction-fed gun does not It is reversed during use, as in a gravity-fed gun, it is possible to omit the air hole in the tank, provided that the connection between the tank and the gun allows air to enter the space between the tank and the inner liner .

Returning now to the paint can 11 of Figure 2, the inner lining 13 will now be described in greater detail, together with a method by which it can be manufactured. The inner lining, shown in isolation in Figures 19 and 2O, is preferably transparent and is thermoformed from a single piece of plastic material, preferably polyethylene or polypropylene. The internal shape of the container 12 imposes the shape of the inner lining. The relatively rigid base 13A is circular and the inner lining 13, similar to the inside of the container 12, is generally cylindrical, but inclines slightly from the mouth towards the base 13A. The portion of the flange 14, similar to the base, is also relatively rigid but the side walls 138 are flexible and, as already described, can be made to crush. However, the inner lining 13 is capable of being straight, without support, on the base 13A with the side walls 138 extended and vertical as shown in Figure 19. When the inner lining 13 is crushed, the relatively rigid base 13A retains its shape but approaches the portion of the flange 14 of the inner liner as a result of the crushing of the side walls 138, as illustrated in Figure 2O. The side walls 138 are crushed, similar to a plastic bag, without breaking (for example, by separation, tearing or cracking).

In one form, the inner liner has a height of approximately 11O mm, a diameter at its base 13A of approximately 78 mm and a diameter at its mouth (excluding the portion of the flange 14) of approximately 86 mm. The base has a thickness of approximately 4OOm, the portion of the flange 14 has a thickness of approximately 9OOm, and the side walls 138 have a thickness of approximately 15Om. In another form, the inner lining has the same height and the same diameters at its base and its mouth, but the base has a thickness of approximately 3OOm, the portion of the flange is approximately 2OOm thick, and the walls laterals 138 have a thickness in the range from 5O to 25O �m.

A method of manufacturing an inner liner, as shown in Figure 19, will be described below with reference to Figures 21 (a) through 21 (c).

A 6O sheet of low density polyethylene (LDPE), approximately 25O x 225 mm and O, 5 mm thick, was tightened by its periphery in the molding frame 61 of a vacuum forming machine. The LDPE material is commercially available, for example, from the firm Plastech Extrusions Ltd. of ididnes, Cheshire, England, and the vacuum forming machine used was the model ��L8 725� of the firm C.�. Clar�e and Company Limited of Ammanford, Carmarthenshire, Wales. It will be appreciated, however, that any suitable plastic material could be used and that the method could be carried out using any suitable vacuum thermoforming / forming machine.

After the sheet 6O was placed in position, the heater bank 62 of the vacuum forming machine was moved to a position above the sheet (as shown in Figure 21 (a)), and the sheet was heated to a soft, flexible state, suitable for vacuum forming. The fact that the sheet reached the appropriate temperature could be seen by the change in its appearance from milky to transparent.

The heater bank 62 was then disassembled and the thick plate 63 of the mold was displaced upwardly from beneath the sheet 6O, leading the mold 64 to contact the sheet to deform it in an upward direction. At that time, the machine's vacuum pump was turned on to extract air from under the 6O sheet. The upward movement of the thick plate 63 of the mold6 continued until said plate reached the upper part of its stroke, in which it was sealed against the frame 61 that holds the sheet 6O (Figure 21 (b)). The mold 64 had a shape corresponding to the internal shape of the container 12 of the paint can 11 of the spray gun.

The operation of the vacuum pump continued with the thick plate of the mold sealed against the frame 61 and the pressure difference created between the upper and lower sides of the sheet 6O caused the latter (which was already in contact with the upper part of the mold 64) will come down to contact the sides of the mold (figure 21 (c)). The thick plate 63 of the mold was then moved away from the cooled sheet 6O, leaving a molded portion 65 with the desired shape of the inner liner 13 and without any crease, corrugation, seam, connection or reinforcement, or some groove in the internal joint of side walls 138 with base 13A. Following its disassembly of the frame 61, the sheet 6O was cut around the mouth of the molded portion 65 to form the flange 14 of the inner liner 13. The width of the flange 14 is determined by the position in which the sheet 6O is trimmed at this stage, and can be adjusted as required.

The process described above was found to produce a molded portion 65 (and, consequently, an inner liner 13) in which part of the plastic sheet 6O that had been in contact with the sides of the mold 64 during the forming process was substantially thinner than the part that had been in contact with the upper part of the mold. The process differs from a usual vacuum forming procedure that would aim to eliminate, as much as possible, any difference in thickness in the molded portion 65 and, for this purpose, would include the additional step of applying air pressure to the portion of air below the heated sheet 6O, after step (a) of Figure 21, to cause the sheet to take a dome shape before the thick plate 63 of the mold is sealed against the frame 61: the thickness of the sheet it would then be relatively uniform when it comes into contact with the mold 64 in step (c) of Figure 21. Generally, in the procedure illustrated in Figure 21, for a given size of sheet 6O, the size of the mold 64 has been discovered that affects the thickness of the sides of the resulting inner lining 13 more than the base. In other words, if the size of the mold 64 is increased, the thickness of the base of the resulting inner liner 13 will be approximately the same, but the sides of the inner liner will be much thinner. On the other hand, if the size of the mold is reduced, it can be discovered that a point is reached where longitudinal folds appear on the sides of the inner lining 13.

If a further reduction of the thickness of the sheet 6O is required in the event that it contacts the sides of the mold 64 in the step (c) of Figure 21, the sheet 6O may be located between two thin metal plates 66 (Figure 22 ) when it is tightened in the frame 61 of the forming machine, each metal plate 66 having a hole 67 in a mold position 64 and a size larger than the largest cross section of the mold. The plates 66 are also tightened in the frame 61 and the procedure of Figure 21 is repeated below. The effect of the plates 66 is that only the central portion of the sheet 6O is directly exposed to the heaters 62 and is extracted on the mold 64 when the latter has been displaced upwards (in this case, through the holes 67 in the plates 66). Thus, somewhat less of the sheet 6O is used in the formation of

molded portion 65 and the resulting inner liner 13 will have a slightly thinner base 13A and shoulder 14 and substantially thinner side walls 138. It is also possible to obtain a comparable result using only the upper plate 66 shown in Figure 22.

As a modification of the procedure illustrated in Figure 22, the plastic sheet 6O may be in the form of a disk of material that is pressed in its periphery between the two plates 66. Depending on the size of the disk, the tight periphery may then form the flange 14 of inner liner 13 and there may be no excess material to be trimmed.

It has been found that an inner liner 13 manufactured by a process such as that described with reference to Figures 21 and 22 will be crushed as described with reference to Figure 2O when used in the tank 11 of the spray gun of Figure 2 The inner liner 13 can also be crushed by hand by pushing the base 13A of said liner toward the rim 14. It has been found that the inner lining is typically capable of being straight, unsupported, on its base 13A and this characteristic, Although it is not essential for the use of the inner liner in the tank 11 of the spray gun, it can be useful for storage purposes. The inner lining has no folds, corrugations, seams, connections or reinforcements, and no grooves in the inner junction of the side walls 138 with the base 13A: consequently, there are no internal places where material can be trapped inside the inner liner . The base 13A of the inner lining will, of course, occupy a certain space in the base of the container 12 of the spray gun 11 and the marks on the wall of the container 12 have to be located to take this fact into account.

Although the inner lining 13 of Figure 19 has been described for use specifically in the paint can 11 of Figure 2, the same or a similar article can be used in other ways (in short, if necessary for appropriate dimensional changes ). For example, an article of the type illustrated in Figure 19 can also be used as an inner liner in many forms of receptacle other than a spray gun tank. It is often desirable to provide a receptacle with a disposable inner liner, for example to keep the receptacle clean, to facilitate cleaning, or to protect the receptacle or its contents. An inner liner of the type illustrated in Figure 19 can be used for any of these purposes and is especially useful in receptacles in which substances are mixed with each other since there are no places on the interior of the liner where material and Stay unmixed.

An article of the type illustrated in Figure 19 can be used, for example, as an interior lining in a receptacle intended to mix paint in a vehicle repair shop, in which case it will provide an attractive alternative to disposable beverage cups often used for that purpose. Before painting the repaired part of a vehicle in a repair shop, the repair operator must mix a dose of paint of the required color that matches the color of the surrounding part of the vehicle. The various components for a dose of paint should be accurately measured, in volume or weight, in a suitable container in which they are thoroughly mixed with each other before being used. If the mixture does not become thorough, or if the receptacle is not absolutely clean, the color / quality of the paint dose (and, consequently, the quality of the repair) may be affected.

To allow the paint mixture to be carried out conveniently, but effectively, an inner liner, of the type illustrated in Figure 19, can be used with a measuring container 7O, as shown in Figure 23. The container of measurement 7O is in the form of a graduated jug with a mouth 71 on a shaped flange 72 and a handle 73. The graduated jug is provided with marks 74 on the side walls, which allow the volume of the content of the graduated jug to be determined . Using the method already described with reference to Figure 21, interior coatings of the type shown in Figure 19 can be manufactured to precisely fit inside the graduated jar 7O and, using said inner coating, the various components for a dose of Paint can be mounted and mixed with each other in the 7O graduated jug without really coming into contact with the latter.

An inner liner 75 suitable for use in the graduated jar 7O is illustrated in Fig. 24. The inner liner 75 has a shape corresponding to the interior of the graduated jar 7O and is generally similar to the inner liner 13 illustrated in Fig. 19. except that the thicker portion of the flange 14, which extends outwardly, from the latter is omitted and the side walls 76 of the inner liner 75 include a shaped flange 77 corresponding to the flange 72 and the mouth 71 of the graduated jug. Since the inner lining 75 fits exactly inside the graduated jar 7O, the possibility of being punctured by the mixing tool when painting paint in the graduated jar is being minimized. In addition, since there are no places within the inner lining where material can be trapped, there is no barrier to the effective mixing of all the material that is measured inside the graduated jar. When the paint has been mixed and transferred from the 7O graduated jug (for example, to the paint can of a spray gun), the inner liner 75, preferably crushed as shown in Figure 2O, is removed and discarded, leaving 7O graduated jug clean and available for additional use.

Since the base 78 of the inner liner 75 occupies a certain amount of space in the lower part of the graduated jar 7O, the marks 74 on the side walls of the graduated jar may have to be placed to take this fact into account. Likewise, it may be desirable, depending on the shape of the graduated jar 7O, to provide an extension on the upper part of the inner liner 75 that can be folded back onto the flange 72 of the graduated jar. Alternatively, or in addition, it may be desirable to seal the inner liner 75 to the graduated jar 7O during use, for example by providing some form of shaped element on the inner liner and the graduated jar, so that they can be adjusted by elastic jump between them. on flanges 77, 72.

Although it is desirable that the inner lining 75 of the graduated jug 7O could be crushed so that it occupies less space after use, this is not absolutely essential. In addition, since the shape of the inner liner 75 is determined by the shape of the interior of the receptacle 7O in which it is to be used, there may be cases where the inner liner is not able to stand straight, without support, on the outside of the receptacle.

As an additional alternative, an article of the type shown in Figure 19 can simply be used as a container, in which case it has the advantage that, although the walls 138 are comparable in flexibility to a plastic bag, the container will be straight upright , without support, while it is being filled and also later. The container can have any appropriate size and can be used to contain many different types of items, including, for example, powders and liquids, or simply as an alternative to the plastic / paper bags that retail merchants provide to customers. . In each case, the container has the advantage that there are no internal places where material can be trapped inside the container. Depending on the contents of the container, it may be desirable to be able to close your mouth, in which case some appropriate form of closure may be provided. The closure may, for example, have the shape of an internal rib on the inside of the container around the middle of the mouth, and a groove coinciding also on the inside of the container around the other half of the mouth, into the which can be pressed the nerve to close the container. The flexibility of the walls 138 of the container further allows the walls to be pressed down around the contents, thereby reducing the empty space within the container, if required.

After use, when it is required to discard the container, the side walls 138 can be crushed by hand by pushing the flange 14 towards the base, so that the container (in this case in the manner illustrated in Figure 2O) requires less space for its elimination. As already mentioned, the side walls 138 are crushed similarly to a plastic bag without breaking (for example, by separation, tearing or cracking).

It will be appreciated that there are many different possible uses for articles of the type shown in Figure 19. Such an inner liner could be used, for example, simply as an inner liner for a garbage can in which it would have the advantage of being a better fit inside the cube than a usual inner lining in the form of a bag, and if it is easier to handle when it is removed from the cube since it will be straight upright on the base 13A. Similar inner liners could also be used in pails or other containers for materials that harden relatively quickly (eg glue, wax or plaster): in some cases, a material such as plaster is actually sold together with a mixing bucket, in which case A supply of interior linings could be included in the package. In some circumstances, it may be appropriate to have a plurality of inner liners, stacked inside each other, in position in a receptacle, so that when an inner liner is removed, the next one is already in position. Furthermore, since the receptacle is intended to contain an inner lining, it is not essential that the walls of the receptacle be solid: the receptacle could have, for example, the shape of a frame for containing the inner lining.

Generally, in an article of the type shown in Figure 19, the base 13A is typically at least 25 µm thick, more typically at least 1OO µm thick. The side walls 138 are thin in comparison to the base 13A, to the point that they can be crushed, as described, to facilitate the removal of the inner liner / container: typically, the thickness of the side walls 138 is less than half of the thickness of the base 13A and may be less than one fifth of the thickness of the base. Depending on the materials used, and the intended use of the inner liner / container, the side walls 13A will usually be less than 25O thick.

For certain uses of an article of the type shown in Figure 19, the portion of the flange 14 may not be essential and may be omitted (as in the inner lining of Figure 24). If no flange 14 is required, the sheet 6O of Figure 21 (c) would be cut, of course, immediately adjacent to the mouth of the molded portion 65. It has been found that the self-supporting nature of the inner liner / container can be retained even if the portion of the flange 14 is omitted.

It should also be noted that the base 13A of a container / inner liner of the type shown in Figure 19 does not have to be circular, but could have another shape, for example rectangular or triangular. In the case of an inner liner for a receptacle, that shape may be imposed by the shape of the receptacle, particularly if the inner liner is required to fit within the latter. In some cases, the base does not have to be rigid.

It will also be appreciated that the procedure illustrated in Figures 21 and 22 is not restricted to the manufacture of

5 inner liners for use in spray guns paint cans and can be adapted to manufacture inner liners / containers for other purposes. It will be appreciated that the process requires that the mold 64 have a slightly inclined shape, the largest cross section being at the lower end (as seen in Figures 21 and 22) to allow the sheet 6O to be disassembled when the forming operation is completed . When the procedure is used to make an inner liner that is required to adjust

10 within a container, this, in turn, requires that the container must be inclined internally in a similar manner. The inner liner / container may be formed from any suitable thermoplastic material capable of forming a thin film that is impermeable to the materials it is intended to contain. In some cases, it may be desirable to use a material in the form of a laminate. For certain applications, such as food packaging, plastics with low permeability may be preferred.

15 gases For most applications, however, polyolefins such as polyethylene or polypropylene are preferred, since they are relatively cheap, can be easily thermoformed and are inert to most aqueous and organic fluids.

Claims (12)

1. Apparatus for spraying liquids, comprising: a fluid reservoir (12), a removable inner liner (13), which can be crushed, located inside the tank, said inner liner (13) having a base (13A) and side walls (138), and a spray nozzle (4) for distributing fluid from inside the inner liner (13), characterized because The inner lining (13) has a stable shape, in its non-crushed state, which corresponds to the inside of the tank (12) and is a tight fit within it, and in which said inner lining (13) is crushed when fluid is removed from said coating during operation of the spraying apparatus.

2.

Apparatus according to claim 1, characterized in that means (12A) are provided to allow air to enter between the tank (12) and the inner lining (13), for example an air discharge, such as a hole (12A), in the deposit (12), preferably on a deposit basis (12).

3.

Apparatus according to claim 1 or claim 2, characterized in that the tank (12) and the inner lining (13) each comprise an open end container having a base and side walls, and in which a removable lid (15) is located at the open end of the tank (12) and secures the inner lining (13) to the tank (12) at said end.

Four.

Apparatus according to claim 3, characterized in that an outlet (16) is arranged in the lid (15), so that liquid passes from inside the inner liner (13) to the spray nozzle (4), and the inner liner

(13) can be removed from the tank (12) together with the cover (15).

5.

Apparatus according to claim 4, characterized in that the inner lining (13) is configured to crush in a longitudinal direction towards the outlet (16) when fluid is removed from said lining during operation of the spraying apparatus, for example, the side walls ( 138) of the inner lining (13) may be thin in comparison to the base (13A) and / or the base (13A) may be rigid compared to the side walls (138), so that the side walls (138) are they crush allowing the base (13A) to retain its shape and approach the outlet (16) when fluid is removed from the inner liner (13).

6.

Apparatus according to any of claims 3 to 5, characterized in that the open end of the tank (12) is larger than the base, for example, the tank (12) can be tilted slightly from the open end towards the base.

7.

Apparatus according to any of the preceding claims, further characterized in that a removable filter (19) for filtering liquid that passes from inside the inner lining (13) to the spray nozzle (4) is arranged.

8.

Apparatus according to any of the preceding claims, characterized in that the inner lining (13) is capable of being straight, without support, on the base (13A), in its unmashed state, with the side walls

(138) extended and vertical. 9. Apparatus according to any of the preceding claims, characterized in that the inner lining (13) has a circular base (13A) and is generally cylindrical in shape. 1O. Apparatus according to any of the preceding claims, characterized in that the inner lining (13) is thermoformed / formed by vacuum from a thermoplastic material, preferably a single piece of thermoplastic material, and preferably has a shaped shape corresponding to the internal shape of the tank. (12).

eleven.

Apparatus according to any of the preceding claims, characterized in that the inner lining (13) has, in its non-crushed state, a uniform internal surface without internal places to trap material within the inner lining (13).

12.

Apparatus according to any of the preceding claims, characterized in that the tank (12) is formed from a plastic material.

13.

Apparatus according to any of the preceding claims, the apparatus having the form of a spray gun (1) fed by gravity.