IE49254B1 - Apparatus for feeding a liquid to an applicator - Google Patents

Description

This invention relates to apparatus for feeding a liquid to an applicator, and in particular, to apparatus primarily intended for painting.

For many years it has been common practice to 5 apply a liquid to a surface using a brush, the brush first being dipped in a reservoir of the liquid and then wiped over the surface to be coated. For relatively large surface areas, rollers rather than brushes are used, the roller also being dipped in a reservoir of the liquid and then rolled across the surface to be coated. As an alternative to the use of a brush or roller, a pad has, in more recent times, sometimes been used: again, the pad is dipped in a reservoir of the liquid and then wiped across the surface to be coated.

The mooe of application described above is unduly time consuming because of the necessity to dip the applicator (brush, roller or pad), in the liquid at frequent intervals in order to replenish the supply of liquid on the applicator. This is a particular problem when the user is standing on a ladder or a - 48254 pair of steps which is frequently the ease, for example when painting a ceiling. To mitigate thi p problem it has been proposed in the case of rollers to increase the liquid capacity of the roller by providing it with its own small liquid reservoir? this attempted solution, however, considerably increases the weight of the roller making it very tiring to use.

From time to time throughout this century it has been proposed to provide the liquid applicator with a connection via a length of tube to a reservoir of liquid and to feed the liquid from the reservoir to the applicator by pressure generated by a pump.

This arrangement has the considerable advantage over the conventional arrangements described above that a user does not continually have to replenish the liquid on the applicator nor does the applicator have to be excessively heavy. These proposed pressurised arrangements have not, however, proved satisfactory. If the . reservoir of liquid and its associated pump is placed on the ground during application of the liquid then a long length of tubing is required between tbe reservoir and the applicator and this can impede the user. If, on the other hand, the reservoir and pump are carried by the user then this impedes the user during painting and is tiring as a result of the weight of the reservoir and pump assembly.

It is known to dispense a liquid from a vessel using a small capsule of pressurized gas.

For example, soda syphons have been available for some years operating on this principle. National Can Corporation have disclosed a paint apparatus in which a vessel of paint is pressure fed by pressurized gas from a capsule to a roller; in operation the vessel is rested on the ground and a long length of tubing connected between the vessel and the roller to allow a user to paint a surface, holding the roller alone. An illustration of this proposed apparatus appeared on pages 30A and 31A of the Journal of Paint Technology Vol. 40, No. 521, June 1968.

Liquid vessels pressurized by capsules of gas are also described in United States Patents Nos. 3 352 457 and 3 558 010 assigned to National Can Corporation.

The specification of United States patent No. 3,558,010 discloses an apparatus for despensing liquid in which a dispensing assembly including a gas or like fluid-containing cartridge and a regulator unit, is’ attached to a vessel and liquid dispensed from the vessel through a tube to an applicator.

The painting apparatus proposed by National Can Corporation still suffers various drawbacks. The use of a long length of tubing can impede the user as already mentioned and also this apparatus, as well as the pressurized arrangements already described, is difficult to clean and messy to use. If the painting apparatus includes its own pressure vessel for containing the paint, the paint must first be poured into this vessel and then, after painting, any paint left in the vessel must be poured out and the vessel, in addition to all the rest of the apparatus, must be cleaned.

The time saved during painting with the apparatus may thus be consumed in extra time spent preparing the apparatus for use and cleaning the apparatus after use.

To some extent, the cleaning operation can be reduced by supplying the paint in its own pressure vessel to which the pressurizing arrangement is then directly attached, since this avoids the need to clean the vessel after use. However, in this case the vessel containing the paint must be specially constructed both to withstand the pressure contained in the vessel during use and to receive the pressurizing arrangement. This greatly increases the cost of the paint vessel over a conventional paint can.

It is an object of the invention to provide an apparatus for feeding liquid under pressure , that mitigates at least some of the disadvantages described above.

According to the invention there is provided an apparatus for feeding liquid under pressure, the apparatus including: a vessel; a liquid container received, in use, within the vessel; a pressurizing assembly including a housing for receiving a capsule of liquefied or pressurized gas and pressure reducing means; a first fluid path extending from the high pressure side of the pressure reducing means, for communicating with the outlet of a capsule inserted, in use, in the housing; a second fluid path extending from the low pressure side of the pressure reducing means into the vessel and into the container; a hand-held applicator for coating a surface with a liquid, and a feed conduit, including a flexible tube extending between the vessel and the applicator, for transferring liquid from the container to the applicator, the feed conduit extending into the container.

The use of a small capsule of liquefied or pressurized gas to provide the pressure in the container provides an extremely compact, lightweight and convenient pressurizing arrangement.

The provision of a container within the vessel is an important feature of the present invention.

The liquid to be fed to an applicator can be sold in the container which is, in use, disposed in the outer vessel and can be of simple construction. After the liquid has been fed from the container, the latter can be thrown away and the vessel does not have to he cleaned.

Preferahly the top of the container is substantially closed; the feed conduit may pass through the top of the vessel and the top of the container to a location adjacent the bottom of the container; the portion of the top of the container through which the feed conduit passes may be in the form of a diaphragm, the diaphragm closing over the junction between the container wall and the feed conduit. This inhibits liquid spilling from the container into the vessel.

A small hole may be provided in the top of the container to allow gas to flow between the container and the vessel to equalize the pressure therein. Alternatively a slit may be provided in the top of the container.

The container may also include a closure member which can be secured over the diaphragm when the container is not in use to seal the container. This preserves the liquid in the container when it is not in use and prevents spillage.

The pressure reducing means may include a valve member mounted in a passage providing comnunication between the first fluid path and the second fluid path, the valve member being movable between a first position in which the passage is closed and a second position in which the passage is open, the valve member being resiliently biased, in use, into the first position, and a piston or diaphragm co-operahle with the valve member and movable away from one position in which the valve member is held in the second position by the piston or diaphragm to another position in which the valve member assumes its first position, the piston or diaphragm being biased to said one position by a spring and being biased away from said one position to another position by the pressure of gas on the low pressure side of the pressure reducing means.

The bias force of the spring acting on the piston or diaphragm may be adjustable, whereby the pressure of gas required to move the piston or diaphragm away from said one position to another position is adjustable.

In use, a capsule of liquified or pressurized gas is located in the housing. The gas may be carbon dioxide or nitrous oxide or any gas which does not have too substantial a deleterious effect on the liquids with which it will come into contact.

The vessel may comprise a body part and a lid.

The lid may be mounted on the hody part of the • vessel such that if excess pressure develops between the lid and the body part the vessel is vented between the lid and the body part.

The pressurizing assembly may he mounted on the lid.

The vessel may be arranged to be carried by a user without using his hands. In this case the user has both hands free to operate the applicator or perform any other function.

A handle may be mounted on the vessel. The handle may be of inverted rectangular 'U' shape.

A clip may be provided on the vessel for attaching the vessel to a belt, to enable a user to suspend the vessel from his waist.

A pressure relief valve may be mounted in a wall of the vessel. The pressure relief valve may be mounted on the lid of the vessel. An actuating arrangement may be provided for actuating the pressure relief valve each time the apparatus is assembled for use. Such an arrangement safeguards against the possibility of the pressure relief valve becoming stuck.

Manually operable means may be provided for venting the pressurized gas in the vessel to return 10 the pressure in the vessel to atmospheric pressure.

The venting means may be provided by the pressure reducing means. Alternatively the venting means may be provided by some other arrangement, for example by the pressure relief valve.

The applicator may, for example, be a pad, a roller or a brush. The length of flexible tube is preferably between one and two metres long. The tube must be long enough to allow a user full range of move ment of the applicator but excessive length is undesir· able as it may impede the user, increases the pressure required to feed the liquid and adds to the length of tube to be cleaned. In a particular example of the invention the tube is one and a quarter metres long. The applicator is preferably provided with a valve for controlling the flow of liquid along the tube.

By way of example, an apparatus for feeding a liquid to an applicator will now be described with reference to the accompanying drawings, in which: Figure 1 is a side view of the apparatus: Figure 2 is a sectional side view of part of the apparatus; Figure 2A is a side view of a closure member 48254 associated with a component shown in Figure 2, Figure 3 is a sectional side view of another part of the apparatus, Figure 4 is a sectional side view of a switch 5 included in the apparatus, Figure 5 is a sectional side view of a small part of the apparatus illustrating a modification which may be made to the apparatus of Figure 2, Figure 6 is a sectional side view of another 10 small part of the apparatus illustrating another modification which may be made to the apparatus of Figure 2, and Figure 7 is a sectional side view of a pressure indicator which may be incorporated in the apparatus.

The apparatus shown in the drawings is also disclosed in our British patent application No. 82.04426.

Figure 1 shows a vessel 1 of circular crosssection having a body 4 and a lid 5 in which is received a container 2 containing paint 16. The 20 vessel 1 and container 2 are made of a plastics material. A feed conduit for the paint is provided by a pipe 3 extending from the centre of the lid 5 of the vessel, towards the bottom of the container.

The container 2 has a well 6 formed in its base and the pipe 3 extends into this well. A flexible tube 7 which is one and a quarter metres long is attached to the end of the pipe 3 and leads, to a paint pad 8.

A pressurizing assembly 9 including a capsule of liquefied gas and a reduction valve (not shown in Figure 1) is mounted eccentrically on the lid 5 and pressurizes the vessel 1 and the inside and outside of the container 2. Also mounted on the lid 5 is a safety valve (not shown in Figure l) and a handle 10 which has two upright limbs extending from the diametrically opposite parts of the periphery of the lid 5 and an integral cross-member connecting the tops of the upright limbs. Thus, the handle 10 is of inverted rectangular *U* shape.

Referring now to Figure 2, which shows the upper portion of the vessel 1 and the container 2 but does not show the pressurizing assembly 9, the lid 5 is screwed onto the body 4 of the vessel and an ’0' ring 60 seals the junction between these parts. The lid 5 has an aperture in which is received a safety valve 11 in the. form of a pressure relief valve. The safety valve 11 comprises a grommet 12 and a valve member 13 received in the grommet 12. In its normal unoperated position shown in Figure 2 the valve member seals the aperture in the lid 5.

The top of the container 2 is defined hy a lid 170 permanently fitted to the container 2 and definipg a diaphragm 14 which has a central aperture through which the pipe 3 extends es a close fit and a small hole η which, ensures equalisation of pressure between the inside and outside of the container hut which, is not sufficiently large to allow paint to pass through the hole except at a very slow rate. The diaphragm 14 is inset from the top of the container defining a recess above the diaphragm which receives a sealing plug 80 (Figure 2A) when the container 2 is not in use to seal the container. While the part 14 is referred to as a diaphragm, it should he understood that this part may he of rigid construction.

The lid 5 has a central cylindrical recess within which the tube 7 is secured to the pipe 3. To assemble the apparatus the end of the tube 7 is passed through the lid 5 and fitted over the pipe 3. The tube 7 is then pulled hack through the lid 5 drawing the end of the pipe 3 into the recess. The assembly of the pipe 3 and tube 7 are a tight fit in the recess and seal the . junction of the tube 7 and the lid 5.

Referring now to Figure 3 which shows the pressurising assembly 9, the assembly has a body 18 including a screw threaded boss 19 which passes through an aperture in the lid 5 of the vessel 1 and to which a nut is secured to retain the assembly 9 on the lid 5· One or more pegs 89 on the base of the body 18 engage in corresponding recesses (not shown) in the top of the lid 5 and locate the assembly 9 on the lid 5. The assembly 9 includes a housing 20 for receiving a capsule 24 of liquid carbon dioxide. A capsule piercing member 21 including a piercer 42 is received in the body 18 and an '0' ring 23 seals the interface of the piercing member 21 and the body 18. The end of the piercing member 21 adjacent the housing 20 has a bore sized to receive the neck of the capsule 24 and an Ό’ ring 45 is seated in r the tore to seal the interface of the capsule neck and the bore. To insert a capsule 24 into the assembly 9 the housing 20 is first unscrewed. The capsule 24 is then placed in the housing 20 and the housing 20 brought into position to be screwed onto the body 18.

At this stage, the neck of the capsule 24 is' in sealing engagement with the piercing member 21 but the capsule is to the left of the position shown in Figure 3 so that the capsule is not yet pierced. As the housing 29 is now screwed onto the body 18, the housing drives the capsule onto the piercer 42 and the capsule is pierced allowing gas to flow along a fluid path from, the capsule through the piercing member 21 into a chamber 25 defined by the piercing member 21 and a valve housing 22 which is screwed onto the piercing member and whose interface with the piercing member is sealed by an '0' ring 46.

The chamber 25 is the high pressure chamber of an adjust able pressure reducing valve assembly which will now be described.

The valve housing 22 slidably receives a valve member 26 which has a closure disc 27 at one end which is in the chamber 25 and a head 28 at the other end.

The closure disc 27 abuts a seat formed on the housing 22 end is resiliently biased by a weak spring 34 against the seat. The right hand' end (as seen in Figure 3) of the body 18 has a bore 3θ in which a piston 29 is slidingly received, an '0' ring 41 being provided around the piston 29 to seal the interface of the piston 29 and the bore 3θ· The bore 30 is closed by a cap assembly 31 screwed onto the exterior of the body 18.

The piston 29 is inwardly biased by a compression spring 32 extending between the piston and the cap assembly 31· In the position shown in Figure 3 the head 28 of the valve member 26 abuts the piston 29. A chamber 33 is defined between the valve housing 22 and the piston 29; this chamber communicates with a duct 44 which extends through the boss 19 of the body 18 and thus provides a fluid path between the vessel 1 find the chamber 33· The cap assembly 31 consists of an operating member 81 screw-threaded on the body 18, an adjusting member 82 screwed into an axial passage of the member 81 so that the relative axial position of the members 81 and 82 can be adjusted by screwing the member 82 into the member 81, and a closure member 83 which fits over the outer end of the axial passage in the member 81 and which conceals the adjusting member 82 and also locks the adjusting member 82 to the operating member 81. The spring 32 extends between the piston 29 and the adjusting member 82, and the maximum separation of the piston 29 and the adjusting member 82 is limited by the engagement of an anchor 84 extending from the piston 29 with the adjusting member 82.

Before insertion of the capsule 24, with the pressure in the vessel 1 atmospheric and with the valve set to provide a finite gauge pressure in the vessel 1, the pressure in chamber 33 is atmospheric so that the piston abuts the end face of the bore 30 and the valve member 26 is pressed against the action of the spring 34 to an open position in which the closure disc 27 is spaced from the seat on the valve housing 22. Upon insertion of the capsule 24, pressurized gas passes through the chamber 25 and the chamber 33' into the vessel 1. As the pressure in the chamber 33 then increases to above atmospheric the piston 29 is pressed outwards against the bias of the spring 32 to a position in which the force of the pressure over the face of the piston substantially equals the force of the spring 32 (there is also a force applied to the piston hy the Bpring 34 But this is so small as to he insignificant). The pressure continues to increase until the piston reaches the position shown in Figure 3 at which stage the closure disc 27 abuts the valve seat of the valve housing 22 and the flow of gas from the capsule stops.

When the pressure in the vessel 1 drops, for example as a result of paint being fed from the container 2, the force exerted by the spring 32 on the piston 29 will overcome the force of the gas pressure and the valve member 26 will be pressed into the open position. Thus the piston 29 and spring 32 regulate the pressure in the vessel 1. During normal operation the operating member 81 is in the position shown in Figure 3. The pressure which this produces in the vessel 1 is dependant upon the axial position of the adjusting meaber 82 and this position is set in the factory to produce the desired pressure and the closure member 83 then positioned over the end of the adjusting member.

For example, screwing the adjusting member 82 towards the piston 29 increases the compression of the spring 32 and therefore increases the pressure at which the valve member 26 is moved into the closed position. In order to set the position to which a user screws the operating member 81, a flange 35 is provided around the periphery of the member 81 and this flange engages a projection 36 on the lid 5 of the vessel 1 when the member 81 is screwed to the pressurized position.

Another projection 37 is provided on the lid 5 and engagement of the flange 35 with this projection 37 limits the outward movement of the member 81 and prevents the cap assembly being removed after the pressurizing assembly 9 is mounted on the lid 5.

In the event of the valve member 26 becoming stuck in the open position, the pressure on the piston 29 gradually increases and the piston is moved outwards against the bias of the spring J2. The bore 30 however is grooved at 38 so that once the piston reaches the encs of the grooves compressed gas can pass around the side of the piston and out to atmosphere through another groove provided along the screw threads of the member 81 and the body 18. A.s an alternative to providing the groove, the member 81 may be apertured.

When the operating member 81 Is unscrewed so that the flange 35 abuts the projection 37, the head 84 extending from the piston 29 is compelled, by engagement with the adjusting member 82, to move outwardly. Thus even if the piston is inclined to stick, once the member 81 is unscrewed, the piston 29 will be in its outward venting position.

In the event of both the valve member 26 and the piston 29 becoming stuck there is still the safety valve member 13 in the top of the vessel 1 to stop excess pressure developing. Still another safety arrangement (not shown) may be provided by deliberately weakening a portion of the vessel 1 so that this portion of the vessel bursts in a controlled manner when the pressure exceeds a predetermined level; alternatively the vessel body 4 may be formed such that upon excess pressure developing, it distorts destroying the seal between the vessel body 4 and tbe lid 5.

Referring again to Figure 1, the paint pad 8 is in some respects similar to a conventional, pad in that it has an outer layer of material 46 supported on a foam backing layer 47 which has a closed cell structure so that it does not absorb the paint; the foam hacking layer is in turn attached to a metal backing plate 48. Unlike conventional paint pads, however, the metal hacking plate has a central aperture at which the flexible tube 7 terminates and the foam backing layer 47 contains a series of passages extending outwardly from the central aperture and terminating within the layer 46 at a plurality of locations distributed over the pad.

The flexible tube 7 passes through the handle 49 of the paint pad 8 and an on/off switch or valve 50 and a regulating screw 51 are provided on the handle 49· The on/off switch 50 is shown in Figure 4 and comprises a switch member 52 pivotally mounted intermediate its ends on the handle 49· One end of the switch member presses via a small plate 53 on the tube 7 and the other end is used to operate the switch. In the position shown in Figure 4 the switch is in the Moff position and the tube 7 is squeezed flat. If a user now pivots the switch member 52 anticlockwise (as seen in Figure 4), the member 52 passes through a dead centre position and then al I ««s the tube 7 to return through its own resilience to a circular cross-section. The plate 53 reduces the frictional force opposing movement of the tube 7 and reduces wear on the tube.

The rate of flow of paint through the tube 7 can be controlled by the regulating scfew 51. Screwing in the screw 51 restricts the internal cross-sectional area of the tube 7 by flattening the tube. In the innermost position of the screw 51 the tube may be completely closed.

The operation of the apparatus shown in Figures 1 to 4 will now be described.

Faint is supplied to a user in the container 2 with the plug 80 sealing over the diaphragm 14. The user removes the plug 60 and places the container 2 in the vessel 1 and screws the lid 5 onto the vessel 1 at the same time inserting the pipe 3 which is secured to the lid 5 into the central aperature in the diaphragm 14. The user then ensures that the switch 50 on the paint pad is in the off position and inserts a capsule 24 into the assembly 9 as already described. The vessel may be carried in the hand by the handle 10 but preferably the handle 10 is suspended from a belt passed around the waist of the user since this is less tiring and also leaves the user with a free hand. The handle 10 may be provided with a clip (not shown) for attaching the vessel 1 to a belt. The vessel 1 is pressurized by screwing in the cap assembly 31· The user adjusts the rate of flow of paint with the regulating screw or regulator 51 and is then able to paint without interruption. The switch 50 enables the user to start and stop painting at will.

In the particular example described the container has a capacity of one litre which is sufficient to paint about twelve square metres of a surface and the capsule holds four litres of gas (at atmospheric pressure). The pressure in the vessel 1 is normally regulated to be in the range of between ten ana twenty pounds per square inch above atmosphere while the pressure in -the capsule ie of the order of 700 to 900 pounds per square inch.

One capsule contains more than sufficient gas to discharge al 1 the paint from a container.

In order to recharge the vessel 1 with a new paint container the cap assembly 31 is unscrewed to the 13mit of its movement; this causes the valve member 26 to close (if it is not already closed) and compressed gas In the vessel 1 moves the piston 29 outwards and escapes to atmosphere around the edge of the piston. Even if the piston 29 tends to stick it is positively pulled outwards by engagement of the head 84 with the adjusting member 82 The lid 5 can then be unscrewed, since the vessel 1 must s be at ambient pressure, the pipe 3 withdrawn from the 15 container 2, the container removed from the vessel 1, and a nev container inserted as described above. As the pipe 3 is withdrawn through the diaphragm 14, paint on the outside of the pipe is wiped off the pipe.

It is helpful for the user to have some indication that the vessel 1 is pressurized and for this purpose a pressure indicator as shown in Figure 7 may be provided. The indicator is mounted on the vessel lid 5 which is formed with an inwardly extending circular rib 152 over which a flexible diaphragm 153 is fitted. The upper face of the diaphragm 153 carries a projection 154 which is accommodated in a hole in the lid 5- When the vessel is not pressurized the diaphragm 153 is not flexed and the top of the projection 154 is below the upper surface of the lid 5. Upon pressurisation of the vessel, however, the diaphragm 153 flexes ana the projection 154 protrudes from the lid 5; the projection 154 is preferably in a colour contrasting with the lid 5 so that it can be easily 9 2 5 4 seen.

After use the apparatus is cleaned. Only the pipe 3, tube 7 and paint pad 8, however, require to be cleaned since the other partB of the apparatus do not cone into contact with the paint. Even if the vessel 1 is inadvertently knocked over during use, the diaphragm 14 retains the paint in the container 2 so that the vessel 1 does not need cleaning. Since both the switch 50 and regplaior 51 act externally on the tube 7 they do not become contaminated with paint'. The paint pad 8 is dlsmantleable to facilitate cleaning.

The O’ ring seals are made of a material which is not affected by the fluid to which they are exposed in use.

Conveniently the vessel 1, the flexible tube 7, the assembly 9, the handle 10, and the paint pad 8 are made of plastics materials. For water based paint the container 2 is preferably made of a plastics material but, since plastics materials are attacked by solvent based paints (for example gloss paints) over an extended period of time, the container 2 is preferably made of metal if it is to contain solvent.based paints. The container 2 may be made in various other forms. For exanple the container may be made of cardboard with a metal foil liner.

It may be desirable to provide means to prevent the insertion in the vessel of an unsuitable container, that is one containing a paint of inferior grade or a grade different to the paint which the apparatus is primarily intended to feed. Such means may, for example, take the form of one or more interengaging ribs and grooves or other formations on the external surface of the container and the inner surface of the vessel, or of suitably shaping the interior contour of the vessel to inhibit the insertion therein of a container which has other than a matching shape.

If desired a multiplicity of balls may be provided 5 on the surface of the paint 16, the balls each being of a diameter slightly bigger than the internal diameter of the pipe 3 and having a density very slightly lower than that of the paint so that they float with nearly all of the ball below the paint surface. A sufficient number of balls are provided such that there are two layers of balls across the entire surface of the paint. As the level of paint in the container 2 drops to a low level the lower layer of balls approach the bottom of the pipe 3; finally when the paint level is almost down to the level of the bottom of the pipe 3 the lower layer of balls reach the level of the bottom of the pipe 3 and one of the bills becomes located over the end of the pipe 3 preventing further flow of liquid. This automatic interruption of the paint flow when the container 2 is almost empty ensures that gas does not enter the pipe 3; if gas were allowed to enter the pipe 3 this could result in sputtering of the paint from the pad 8.

In the drawings the pressure vessel 1 is shown with square comers and straight sides. In accordance with well known design procedure for such vessels, however, the comers are preferably rounded off and the sides bowed outwardly.

After use of apparatus described above, the apparatus may be cleaned by pumping a solvent, which in the case of water based paints may be water, through the apparatus using the pressure of the capsule of carbon dioxide.

In the illustrated apparatus a paint pad is attached to the free end of the tube 7. However, a paint brush or roller may alternatively be attached, these devices having an on/off switch and a regulator similar to the paint pad. When using a brush, the flow of paint may be required to be somewhat slower and this can be achieved by appropriate adjustment of the regulator on the brush handle. If desired the applicator may be of a modular construction consisting of a handle incorporating the on/off switch and the regulator and a plurality of heads including at least one pad, roller and brush which can be attached to the handle. The on/off switch and the regulator may be combined into a single control if desired. For the sake of simplicity the regulator may be omitted.

A shoulder strap may be attached to the vessel 1 to allow a user to carry the vessel over his shoulder or any other arrangement may be provided to enable a user to carry the vessel.

The lid 5 may be clasped onto the body 4 of the vessel 1 by a plurality of toggle clasps, instead of screwing the lid onto the body. This has the advantage that the '0' ring or diaphragm is not subjected to a rubbing action upon tightening of the lid 5. Furthermore the toggle clasps can be spring biased into their closed position in such a way that if the pressure in the vessel exceeds a predetermined level at least one of the toggle clasps is foreeefopen and the lid 5 lifts off the vessel body 4.

A particular example of a lifting lid assembly is shown in Figure 5. In this figure, the vessel body 104 is shown with a lifting lid 105, an 0 ring seal 106 being provided between portions of the walls 104 and 105 which with the vessel 1 unpressurized are overlapping. The lid 105 is retained on the body 104 by a ring clasp 107 screwed onto the body 104 and a number of springs108 are provided around the periphery of the lid 105 between the lid 105 and the ring clamp 107. In the position shown in Figure 5, the vessel is unpressured, the lid 105 rests on top of the body 104 and the springs 108 are substantially unstressed.

As the vessel 1 is pressurized the lid 105 lifts off the body 104 and the springs 108 become stressed.

Under normal operating pressure portions of the walls 104 and 105 continue to overlap and the '0' ring 106 seals the interface therebetween. Upon excess pressure developing, however, the springs 108 are further compressed and the lid 105 is lifted clear of the '0' ring 106 venting the vessel.

In the arrangement shown in Figure 2 the diaphragm 14 has a hole 15 which ensures equalisation of pressure between the opposite sides of the diaphragm. In place of the aperture, a slit may be provided in' the diaphragm, extending for example radially from the central aperture in the diaphragm.

Alternatively it may be possible to omit both the pin hole and the slit and rely on the diaphragm flexing in the region of its central aperture to allow the passage of gas between the diaphragm 14 and the pipe 3.

The diaphragm 14 may, if desired, initially be without the central aperture. In this case the pipe 3 is provided with a pointed end and is sufficiently stiff to puncture the diaphragm when it is first pressed through the diaphragm. It may be advantageous to neck the pipe where lt engages the diaphragm. This may be advantageous if an anti-sputter arrangement of a kind which will now be described is employed in the apparatus shown in Figure 2. Ihe anti—sputter arrangement con5 ’ sista of providing a compressioh spring UDder the container 2 so that as the container 2 empties of paint it becomes lighter and is lifted up relative to the vessel 1, and, when the container 2 is virtually empty of paint, the.end of the pipe 3 bears against the bottom of the container 2 sealing over the pipe 3· If desired a resilient member for example a closed cell foam may be provided on the bottom of the container 2 under the pipe 3 to ensure that a good seal is ohtained between the pipe and the container.

Necking the pipe 3 where it passes through the diaphragm ensures that there is very little resistance to relative motion of the container 2 and the pipe 3 and • also allows free flow of gas into the container. When the pipe 3’ is withdrawn from the container 2 after use the lower unnecked portion of the pipe is wiped clean as it passes through the diaphragm.

In the pressure reducing valve assembly shown in Figure 3 a piston 29 is used. As an alternative a diaphragm connected to the wall of the bore 3θ and spring biased in .the same manner as the piston 29 could be used. In this case it may not be possible for gas pressure to be vented through the cap 31. An alternative way of venting the gas may be to open the safety valve.

The spring 34 vhich biases the valve member 26 into its closed position may be omitted since gas pressure froa the capsule 24 can be used to perform this biasing function.

The housing 20 of the pressure reducing valve assembly 9 may be provided with external radially projecting fins to facilitate screwing and unscrewing of the housing 20. Also the capsule 24 may be located in the housing 20 in such a way that when the housing Is unscrewed the capsule 24 is automatically withdrawn from the piercer 42 and comes away with the housing from which it is then removed.

The safety valve assembly may be modified in such a way that every time the lid 5 is secured to the vessel body 4 the safety valve is tested. An arrange10 ment of this kind is shown in Figured. In this arrangement the safety valve assembly consists of a housing 110 in which a valve member 111 carrying a closure member 112 is mounted. A spring 113 biases the closure member 112 onto a spherical seat formed at the bottom of the housing 110. Upon excess pressure developing the closure member 112 is lifted off its seat venting the vessel. The interface of the vessel body 114 and screw-on lid 115 is around the outside of the body and is sealed hy an *0’ ring. On one portion of the top of the vessel body 114 a ramp shaped cam surface 116 is provided. A lever 117 is pivotally mounted on the lid 115 at one end and has a cam follower 118 on the other engaging the top of the vessel body 114. Intermediate the ends of the lever 117, the lever touches or is spaced just underneath the lower end of the valve member 111.

As the lid 115 is screwed onto the body 114, the lever 117 engages the cam surface 116 once in each revolution of the lid and this engagement raises the lever 117 lifting the valve member 111 into its vented position. When the lid is fully screwed on, the cam surface 116 is arranged to be spaced circumferentially from the cam follower 118 so that the safety valve assembly is closed.

Although the apparatus has been described with reference to the application of paint, it can be used to apply other liquids to a surface. For example it can be used to apply preservative to a wooden surface or for washing surfaces. The apparatus can also be used to feed liquids to other kinds of applicators, for example to a spray head. Vith a spray head, the apparatus can be used as a garden spray apparatus.

Claims (19)

1. CLAIMS:1. An apparatus for feeding liquid under pressure, the apparatus including: a vessel; 5 a liquid container received, in use, within the vessel; a pressurizing assembly including a housing for receiving a capsule of liquefied or pressurized gas and pressure reducing means; 10 a first fluid path extending from the high pressure side of the pressure reducing means for communicating with the outlet of a capsule inserted, in use, in the housing; a second fluid path extending from the low pressure 15 side of the pressure reducing means into the vessel and into the container; a hand-held applicator for coating a surface with a liquid, and a feed conduit, including a flexible tube extending 2. O between the vessel and the applicator, for-transferring liquid from the container to the applicator, the feed conduit extending into the container.

2. An apparatus according to claim 1, in which the top of the container is substantially closed. 25

3. An apparatus according to claim 2, in which the feed conduit passes through the top of the vessel and the top of the container to a location adjacent the bottom of the container.

4. An apparatus according to claim 3,in which the 30 bottom of the container has a well formed therein, and wherein the end of the feed conduit is within the well.

5. An apparatus according to claim 3 or 4, in which the portion of the top of the container through which the feed conduit passes is in the form of a diaphragm, the 35 diaphragm closing over the junction between the container wall and the feed conduit.

6. An apparatus according to claim 5, in which a small hole or slit is provided in the diaphragm defining a part of the second fluid path.

7. An apparatus according to claim 5 or 6 in which the container includes a closure member which can be secured over the diaphragm when the container is not in use to seal the container.

8. An apparatus according to any preceding claim in which means to prevent the insertion in the vessel of an unsuited container are provided.

9. An apparatus according to any preceding claim in which the pressure reducing means includes a valve member mounted in a passage providing communication between the first fluid path and the second fluid path, the valve member being movable between a first position in which the passage is closed and a second position in which the passage is open, the valve member being resiliently biased, in use, into the first position, and a piston or diaphragm eooperable with the valve member and movable away from one position in vSiieh the valve member is held in the second position by the piston or diaphragm to another position in which the valve member assumes its first position, the piston or diaphragm being biased to said one position by a spring and being biased away from said one position to another position by the pressure of gas on the low pressure side of the pressure reducing means.

10. An apparatus according to claim 9 in which the bias force of the spring acting on the piston or diaphragm is adjustable, whereby the pressure of gas required to move the piston or diaphragm away from said one position to another position is adjustable.

11. An apparatus according to any preceding claim in which the flexible tube is between one and two metres long.

12. An apparatus according to any preceding claim in which the feed conduit comprises a relatively rigid pipe in the vessel and a flexible tube extending between the pipe and the applicator, one end of the tube being fitted over one end of the pipe and the junction of the tube and the pipe being a tight fit in an internal recess of the vessel, the tube passing through a bore extending between the recess and the exterior of the vessel.

13. An apparatus according to any preceding claim in which the vessel includes a body part and a lid. 5

14. An apparatus according to claim 13 in which the pressurizing assembly is mounted on the lid.

15. An apparatus according to any preceding claim in which the vessel is arranged to be carried by a user without using his hands. 10

16. An apparatus according to claim 15 in which a clip is provided on the vessel for attaching the vessel to a belt.

17. An apparatus according to any preceding claim in which a pressure relief valve is mounted in a wall 15 of the vessel.

18. An apparatus for feeding liquid under pressure to an applicator, the apparatus being substantially as herein described with reference to and as illustrated by Figures 1, 2, 2A and 3 of the accompanying drawings.

19. 20 19- An apparatus according to claim 18, the apparatus being substantially as herein further described with reference to and as illustrated by Figure 4, or by Figure 5, or by Figure 6 or by Figure 7 of the accompanying drawings.