EP0441538A2

EP0441538A2 - Dispensing apparatus

Info

Publication number: EP0441538A2
Application number: EP91300786A
Authority: EP
Inventors: Thomas Campbell Wallace
Original assignee: Rawlplug Co Ltd
Current assignee: Rawlplug Co Ltd
Priority date: 1990-02-03
Filing date: 1991-01-31
Publication date: 1991-08-14
Also published as: EP0441538A3

Abstract

Dispensing apparatus is described for dispensing a first component (8) and a second component (10). The components (8, 10) are stored within a flexible container (2) and a common outlet chamber (28) is provided to receive the components when they are expelled from the container (2). The outlet chamber (28) has mixing means (32) which mixes the components (8, 10) to form a reactive mixture. Typically, the components (8, 10) are expelled from the container (2) by compression means which applies a compression force to the container. The apparatus may also comprise a housing in which the container (2) is located and the compression means may comprise a piston (24). Typically, the container (2) comprises an outer container (2) and an inner container (4) located within the outer container (2).

Description

This invention relates to dispensing apparatus and to a method of using it.
In the building industry it is often necessary to secure items against a rigid structure of, for example, concrete. Expanding bolts are a traditional way of effecting this in situations where the structure has little or no resilience and is therefore incapable of providing resistance to withdrawal of a simple screw or bolt. Expanding bolts, however, are relatively expensive and require a hole of the correct diameter to be drilled into the structure.
It has also been proposed to surround a bolt or other anchor in a drilled hole with a curable resin, so that the resin sets between the anchor and the wall of the hole to secure the anchor against withdrawal. The curable resins used are generally in two component parts each of which is reactive with the other to provide the resin on mixing. In one system these components have been provided in separate rigid chambers of a delivery apparatus, each chamber being cylindrical and having its own piston which is actuable to drive the reactive component from the chamber into a common outlet in which the components are mixed and thence delivered through a nozzle.
In another system the components are held in separate rigid chambers disposed one within the other to provide an inner cylindrical chamber and an outer annular chamber. Again, each chamber is provided with an individual piston which drives the respective reactant into a common mixing outlet.
In both of these systems it is necessary to provide an expensive and particular delivery gun having a dual drive for moving the two pistons in unison to obtain the correct mix of reactants at the outlet. Further, the chamber walls are rigid and therefore require substantial amounts of material in their manufacture; they are also designed to be disposable and are therefore expensive to replace.
According to the present invention there is provided dispensing apparatus, comprising a first component and a second component in flexible container means, a common outlet chamber disposed so as to receive the first and second components from the container means, and means for mixing the first and second components in the common outlet chamber to form a reactive mixture.
Preferably, the first and second components are expelled from the container means into the common outlet chamber by a compression force applied to the container means by compression means which could comprise a psiton.
Typically, the reactive mixture may be a curable mix which may form a rigid final product. The components may for example be monomers which react to produce a thermosetting polymer resin. However, the first and second components, when mixed, could form a deformable sealant material, such as an elastomeric polymer.
Typically, when the final mixed product is a thermosetting resin, it is a polyester resin and one component may be the resin and the other component a catalyst to cure the resin. Preferably, the ratio of resin to catalyst is 7:1.
Typically, the first and second components have substantially similar flow properties to ensure that the components are dispensed from the apparatus in the desired proportions.
The components may be held in close contact within the container means, in which case it is desirable that they should be reactive to a substantial extent only when subjected to some externally-applied treatment such as heat or intimate mixing, so as to provide a reasonable shelf life and handling capability for the apparatus. Alternatively the components may be physically separated within the container means, for example by a wall or membrane, so that they come into contact only on entering the common outlet chamber; the components may be spontaneously reactive.
The container means may be a single container, a separate container for each component, or a combination of both these. Preferably, the container means comprises an outer container which contains the first component and an inner container located within the outer container and in the first component and which contains the second component. Preferably, where one component is a resin and the other is a catalyst and they are mixed in the ratio 7:1, the first component is the resin and the second component is the catalyst, so that the resin is located between the outer and inner containers and the catalyst is located in the second container. Typically, a portion of the surface of the outer and inner containers coincide, and where the containers are cylinders the portion is a line which extends along the length of both cylinders. Preferably, the line is the seam of the containers.
The container could be polyethylene. However, preferably the container is a polyester-nylon laminate comprising a layer of nylon sandwiched between two layers of polyester. This would reduce solvent evaporation from the components and increase the shelf life of the container and components. Alternatively, the flexible container could be formed from a foil plastic laminate and this would reduce expansion of the flexible container under pressure.
The container means may be disposed within a housing such for example as a cylinder, and a piston may be provided in the housing to compress the container means to drive the components into the common outlet. A delivery gun may be provided to actuate the piston. As an alternative to using a piston the container means could be compressed manually by an operator, compressed by a roller device, compressed by rolling the container means on to itself or compressed by a power-assisted pressure applicator.
Typically, where the housing used is a cylinder the external dimensions of the flexible container are such that when the piston compresses the flexible container, the pressure exerted on the flexible container is not substantially coupled to the walls of the cylinder. Preferably, there is a radial clearance of approximately 2.5mm when a cylinder having an inside diameter of 40 mm is used. This reduces expansion of the inside diameter of the cylinder due to the pressure and helps reduce the creation of a gap between the cylinder and piston in which the flexible container may become jammed. This could jam the piston and prevent the piston expelling the components from the flexible container. Preferably, the cylinder is a standard plastic cylinder from which, conventionally, mastic silicon sealant is dispensed.
The use of the standard plastic cylinder as the housing enables the components to be dispensed using a standard, "off the shelf" mastic gun and obviates the need for a special delivery gun.
Preferably, the common outlet chamber is removable to enable the outlet chamber to be replaced. Typically, where a housing is provided the outlet chamber is coupled on to the housing. Preferably, the outlet chamber comprises a nozzle which dispenses the first and second components from the apparatus and typically the mixing means is located within the nozzle.
Typically, the outlet chamber may include cutting means so that when the flexible container means is sealed, the cutting means may be used to open the container means so the first and second components may pass into the outlet chamber. The cutting means could comprise a blade mounted on the outlet chamber which cuts the container means when the outlet chamber and container means are moved relative to each other, or a number of sharp points mounted on the outlet chamber which may pierce the container means. Preferably, the container means is opened so that the portion of the container means which is cut remains attached to the rest of the container means.
The invention is also a method of using dispensing apparatus comprising ejecting from flexible container means first and second reactive components into a common outlet, mixing the components together in the outlet and delivering the resulting mix from the outlet.
The method could be used for dispensing, for example a curable mix, into a pre-drilled hole in rigid material.
Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which:

Figs 1 and 2 are end sectional views of alternative flexible containers for use in the apparatus and method of the invention;
Figs 3 and 4 are side views of the containers of Figs 1 and 2 respectively; and
Fig. 5 is a side sectional view of apparatus in accordance with the invention.

Referring first to Figs 1 and 3, the container illustrated is a length of plastics membrane formed by extrusion into first and second channels one within the other. The channel walls of 2, 4 are interconnected at 6. The first and second channels are filled with monomers 8, 10 which when mixed react to form a curable resin which spontaneously sets rigid. The channels are crimped together for closure at both ends. Typically, the monomers 8, 10 are a polyester resin and catalyst, respectively in the ratio of 7 parts resin to 1 part catalyst.
In Figs 2 and 4 the container is formed by a single-walled extruded membrane 12, again crimped at both ends, and filled with first and second monomers 14, 16. The monomers 14, 16 are in contact along their interface 18, but do not react until intimately mixed together.
Referring now to Fig 5, the apparatus of this embodiment of the invention has a flexible container 20 similar to that of Figs 1 and 3 disposed within a cylindrical tube 22. A plastics plug 24 is provided within the tube 22 at one end and is slidable along the interior of the tube. The other end of the tube 22 is closed by a plastics cap 26 which fits over the tube end and has an externally-threaded spout 28. A tapered nozzle 30 is internally threaded and fits onto the spout 28.
In this particular example, the tube 22 is a standard tube which is normally used for single component silicon sealant and which fits a standard mastic delivery gun. The tube 22 has an inside diameter of approximately 46mm. In this example the flexible container 20 has an outside diameter of approximately 40mm so that there is a gap between the flexible container 20 and the tube 22. Hence, when the flexible container is compressed by plug 24, the pressure is not coupled onto the walls of the tube 22 which substantially prevents expansion of the tube 22 due to the plug pressure and possible jamming of the plug in the tube 22.
The nozzle 30 has an insert 32 within its bore at an end portion adjacent the cap 26, the insert 32 being in the form of a central spindle from which extend radial projections for interrupting flow of material along the nozzle 30 and producing a turbulent and mixing effect on the material.
When the apparatus is to be used, the container 20 is ruptured across one end with, for example, a knife or other cutter, and placed into the tube 22 with the ruptured end adjacent the cap 26. The plug 24 is then inserted into the other end of the tube 22 to retain the container 20.
The apparatus is then fitted into a standard delivery gun 34 such as those in common use for delivering sealant and other materials in the building and do-it-yourself markets. The gun 34 has a lever-operated piston 36 which engages the slidable plug 24 and on actuation drives the plug 24 along the tube 22, compressing the container 20. This forces the reactive components from their respective channels in the container 20 through the ruptured end of the container and thence through the spout 28 into the nozzle 30.
The reactive components are originally held in the channels of the container 20 in the correct proportions for full reaction between them, and the cross-sections of the channels are selected accordingly. Thus, when the components reach the radial projections of the insert 32 and move past them they are mixed thoroughly in the correct proportions until they form a curable resin.
Continued actuation of the gun 34 drives the resin through the outlet end of the nozzle 30 which can be directed into a pre-formed hole in concrete, brick or other rigid material. An anchor, for example in the form of a bolt or stud, is embedded in the resin which is then allowed to cure to form a rigid plug which firmly retains the anchor in the hole.
In many cases the container 20 will be of sufficient capacity for use in filling a number of holes, and it will be appreciated that the resin will cure in the nozzle 30 if this capacity is not fully utilised in less time than it takes for the resin to cure after mixing. In this case the nozzle 30 can be unscrewed from the spout 28 and replaced by a fresh nozzle 30; the cap 26 may also be replaced if necessary, and both components can be of inexpensive material and construction.
When the container 20 is exhausted it can be disposed of, and the only waste material is the membrane of which it is made, the nozzle 30, cap 26 and plug 24. The more substantial tube 22 can be re-used as it is substantially uncontaminated by resin, being protected by the container 20 and cap 26.
Thus the apparatus and method of these embodiments of the invention provide a simple and inexpensive means of delivering curable resin to a fixing system and allow a substantial proportion of the apparatus to be re-used. They also allow the use of a conventional inexpensive delivery gun instead of requiring a custom-built item.
Also, as the components are retained within the container 20, it is not necessary for the plug 24 to seal against the inside wall of the tube 22. Hence, the tube 22 may be formed by an extrusion process instead of by a moulding process. Normally this is not possible as extruded tubes do not have a fine surface finish and so the plug 24 will not seal properly with the inside wall. However, extruded tubes are cheaper and do not require a slight taper to enable them to be removed from the mould. Hence, the tube 22 can be extruded with a thicker wall using cheaper tooling than for conventional systems.
Other advantages of the system as described above are that the axial force of the gun 34 forces the cut end of the container 20 against the wall of the cap 26. This automatically creates a seal against back-flow of material inside the cap 26 and as the container 20 is flexible it fills the corners of the cap 26 which means that no special shape is required for the cap 26. Also, the container 20 crumples from the plug 24 because of the pressure in the container 20 and so prevents collapse at the cap end of the container 20.
In addition the reduced complexity in the construction of the container 20 compared with the conventional two part mixing systems also reduces the cost of the system.
In some embodiments puncturing means may be provided within the tube or cap so that the container can be inserted intact into the tube prior to use and is ruptured automatically on application of force at the commencement of the mixing and delivery operation. In some cases an alternative delivery system to the gun may be used, such as manual compression of the container or rolling the container up on itself to provide the compression force.
Modifications and improvements may be incorporated without departing from the scope of the invention.

Claims

Dispensing apparatus comprising a first component (8) and a second component (10) in flexible container means (2), a common outlet chamber (28) disposed so as to receive the first and second components (8, 10) from the container means (2), and means (32) for mixing the first and second components (8, 10) in the common outlet chamber (28) to form a reactive mixture.
Dispensing apparatus according to Claim 1, further comprising compression means (24) for applying a compression force to the container means (2).
Dispensing apparatus according to Claim 2, wherein the compression means comprises a piston (24).
Dispensing apparatus according to any of Claims 1 to 3, further comprising a housing (22) within which the container means (2) is disposed.
Dispensing apparatus according to Claim 4, wherein the common outlet chamber (28) is coupled to the housing (22).
Dispensing apparatus according to Claim 2, further comprising a housing (22) within which the container means (2) is disposed and wherein the external dimensions of the container means (2) in its uncompressed state are less than the internal dimensions of the housing (22).
Dispensing apparatus according to any of the preceding Claims, wherein the first and second components (8, 10)have similar flow properties.
Dispensing apparatus according to any of the preceding Claims, wherein the container means comprises a container (2, 4) for each component (8, 10).
Dispensing apparatus according to Claim 8, wherein the container means comprises an outer container (2) and an inner container (4) located within the outer container (2).
Dispensing apparatus according to any of the preceding Claims, wherein the common outlet chamber (28) includes cutting means engageable with the container means (2).