GB2135654A - Mixing and dispensing liquids - Google Patents

Abstract

A container 1 for sealant or the like comprises a hollow cylinder with a rim 3 at each end, and a removable lid closing each end and being a push fit whereby it may be removed and replaced. In use, the upper lid of the container is removed and the container is inverted and clamped on apparatus which receives the sealant in cylinder 9 and mixes it in mixing chamber 13 with an accelerator compound stored in reservoir 11 and discharged from cylinder 10. To help the downward movement of the sealant from the container 1, the other lid thereof is removed and a heavy follower plate 30 is placed on the sealant. <IMAGE>

Description

SPECIFICATION Mixing and dispensing liquids This invention relates to liquid dispensing apparatus and methods and is particularly applicable to apparatus and methods for mixing in predetermined proportions two liquids and dispensing the resulting mixture.

Such operations are now very common and are required in connection with the use of a number of adhesives and sealants, for example. One- and two-part sealants are used extensively in the building industry, for example in the manufacture of sealed double glazing units. These units consist of two panes of glass separated by a hollow spacer and a sealant is applied around the entire periphery of the unit. Some popular sealants comprise a sealant base and an accelerator compound which have to be mixed together in predetermined proportions before the sealant is used. Factories which manufacture very large quantities of double glazing units may purchase the sealant base in 200 litre drums and the accelerator is available in smaller containers.

Machines are available for mixing and dispensing the sealant: a typical example consists in effect of two pneumatic lift pumps of different bore and/or stroke arranged to supply the respective materials to a mixing chamber. Because of the size of the drum, the drum has to be placed on the ground and the material lifted by the pumps. Because of the high viscosity of the sealant it is necessary to assist the pump action by pressing down a follower plate onto the sealant material by meaiis of a powerful air ram. Such a machine is very substantial and expensive. Further, because of the size of the machine considerable quantities of material are wasted at the end of each period of use when mixed material has top be purged from its passages.

Clearly such a machine is unsuitable for a smaller manufacturer who requires smaller quantities of mixed sealant and cannot justify the capital costs involved in the iarge machine.

Hitherto there has been no satisfactory way of measuring, mixing and dispensing a two-part sealant in relatively small quantities. Typically, smaller users of sealant may measure the components of the sealant into a container by using a plastic cup or the like and then mix the components by hand. Such a process has the disadvantages that it is inaccurate, toxic fumes and materials may be released into the working environment, the resulting sealant may be of poor quality because of air mixed into the compound and because it begins to set from the moment it is mixed, considerable time is wasted in mixing the components, and it is difficult to estimate the quantity of sealant to mix so as to avoid wastage or shortage of sealant.

Viewed from one aspect the invention provides in combination a container having a removable lid at each end and containing a liquid to be dispensed, and apparatus adapted to releasably secure the container thereon, said apparatus including means for delivering said liquid downwards from the bottom of the container.

Preferably the container has a rolled rim at each end and a lid on each end which is removable and replaceable. In use, the lower lid is placed on the container and the container is filled with the liquid.

The upper lid is then fitted. To remove the liquid from the container in accordance with the invention the upper lid is removed and the container is then inverted and positioned on the delivery apparatus. It is releasably secured thereon, for example by toggle clips engaging the lower rolled rim. The apparatus is particularly suitable for dispensing viscous liquids and to enable such liquids to flow downwards it is necessary to remove the upper lid of the container, preferably applying a weighted follower plate to the exposed liquid.

The general inventive concept of providing the viscous liquid in a container with a removable lid at each end and delivering the liquid by means of apparatus which draws the liquid downwardly of the open lower end of the container leads to many advantages, the chief of which is the ability to provide a delivering machine which is simple and economical to manufacture. Specifically, by delivering the liquid downwardly the use of a lift pump and a ram to force the liquid upwards is avoided.

Viewed from another aspect, this invention provides a method of delivering a liquid component, comprising providing the component in a container with a removable lid on each end, removing the lower lid to allow the delivery of the component downwardly, and removing the upper lid to provide a vent to allow the component to move downwardly out of the container. As mentioned above, the downward movement is preferably assisted by a follower plate placed on top of the component.

Clearly the container having a removable lid at each end and containing the component to be delivered and the use of such a container are essential elements of the aspects of the invention referred to above.

Although not limited thereto, the invention is particularly applicable to metering, mixing and delivering the two components of a two-part sealant. Typically the sealant base is viscous and the accelerator, which is to be mixed therewith in a relativeiy small proportion, e.g. one part in twelve, is more mobile. A reservoir may be provided for the second component and refilled as required. Typical accelerators are sufficiently liquid to be easily poured into a reservoir. Preferably the two components are metered by means of respective cylinders and pistons of defined stroke.

Viewed from another aspect, the invention provides apparatus for metering and mixing in predetermined proportions two liquids, comprising means for receiving and releasably securing a container of a first said liquid, a reservoir for receiving the second said liquid, two cylinders and pistons disposed at a lower level than the container and reservoir respectively, the piston rods being rigidly connected together, and means for reciprocatingly driving the piston rods, the first cylinder having an inlet for receiving the first liquid from the container and an outlet for delivering a substantially fixed amount of the first liquid to a mixing chamber on each stroke of the piston rods, and the second cylinder having an inlet for receiving the second liquid from the reservoir and an outlet for delivering a predetermined quantity of said second liquid to the mixing chamber on each stroke of the piston rods. Preferably a nonreturn valve is provided between the outlet of the first cylinder and the mixing chamber, and preferably a manually operable valve is provided in the flow path of the second liquid. The manually operable valve may be closed when it is desired to feed only the first liquid, for example to purge the mixing chamber of the mixed sealant. Alternatively the valve may be a three-port valve arranged to direct the second liquid to the mixing chamber or to return it to the reservoir.

The apparatus preferably includes a static mixer connected to receive the liquids from the mixing chamber and to deliver the mixture to an outlet A static mixer comprises a passage with a plurality of vanes disposed therein so as to force the liquids to travel a tortuous path during which they intermix. Such a mixer is preferable to a mechanical mixer which may result in undesired heating of the mixture.

Viewed from another aspect the invention provides a container for sealant or the like comprising a hollow cylinder with a rim at each end, and a removable lid closing each end and being a push fit whereby it may be removed and replaced. A moulded plastics or a cardboard cylinder may be used in some circumstances but preferably the cylinder is metal and is formed with rolled rims. Each rolled rim is preferably rolled outwardly beyond the circumference of the cylinder. This provides a portion which may be gripped by the releasable securing means when the container is positioned on the rest of the apparatus.The opening at each end of the cylinder is preferably of the full width of the cylinder, i.e., is completely free of obstructions such as a flange or the like so that the contents of the container can flow out unhindered and so that a full-width follower can be used to assist the flow.

It is to be understood that the term "liquid" as used herein is intended to cover materials of any viscosity such that they can be made to flow from a container and be moved by a piston and cylinder and includes not only mobile liquids but heavy pastes, for example.

An embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is an axial section of a container according to the invention; Figure 2 is a schematic side view of metering, mixing and dispensing apparatus according to the invention; and Figure 3 is a plan view of the apparatus of Figure 2 with the container removed.

Referring first to Figure 1, there is shown a container 1 for sealant base or the like which may for example be a drum of about 20 litres capacity.

It comprises a hollow metal cylinder 2 provided with a rolled rim 3 at each end. The cylinder 2 may be made in the conventional manner by rolling a metal sheet and forming a seal by pressing, welding or soldering. The rim 3 is rolled outwardly so as to have a diameter larger than the diameter of the cylinder 2 to enable it to be secured to the rest of the dispensing apparatus as described below and it will be noted that the opening at each end of the cylinder is of the full width of the cylinder, i.e., is completely free of obstructions such as a flange or the like. A lid 4 of conventional design is a push fit in each end of the cylinder 2 so as to be removable and replaceable. The container 1 may be filled by fitting the lower lid, filling the container and then fitting the upper lid.

Referring now to Figures 2 and 3, the dispensing apparatus comprises a tubular frame 5 provided with a pair of wheels 6 and a pair of feet 7 to enable it to be moved easily. Mounted within the frame 5 are an air motor 8 arranged to drive together the pistons of two cylinders 9 and 10. A container 1 containing for example a polysulphide or silicone sealant base is arranged to supply cylinder 9 and a reservoir 11 containing for example accelerator supplies cylinder 10. The outlets of the cylinders 9 and 10 are connected to a mixing chamber 13, the passage from the outlet of cylinder 9 being provided with a non-return valve 14 and the passage from the outlet of cylinder 10 being provided with a manually operable valve 12 which is selectively operable to cause the accelerator to be delivered either to the mixing chamber or back to the reservoir.A static mixer and delivery tube 15 is arranged to mix and deliver the two components from the mixing chamber 13. As may be seen in Figure 3, the delivery tube 15 may be pivoted outwardly of the frame 5 so as to make it more convenient to fill sealant guns and other containers with the mixed material.

Mounted at the top of the frame is a support plate 16 arranged to receive the container 1 thereon. The container 1 may, for example, be a drum of 20 litres capacity. It may be mounted on the support plate 16 via a rubber mat 17 to provide a seal for preventing leakage of sealant base. The container 1 is secured to the support plate 16 by means of releasable securing devices 1 8, preferably three in number, which engage the rolled rim 3. For example, the securing devices 18 may take the form of a small plate or arm which is urged down a threaded post by means of a nut or the like. Alternatively, quick-release toggle latches may be employed. A well 19 formed of metal sheet is positioned below the support plate 16 and connected thereto. It includes a conical portion connected to the cylinder 9 and arranged to deliver the sealant base downwardly thereto.

The air motor 8 and cylinders 9 and 10 will now be described in more detail. The driving rod 20 of the motor 8 is rigidly connected to the piston rod 21 of the cylinder 9 and the piston rod 22 of the cylinder 10 by a metal block 23. For example the rods and block may be formed with mating threads. The block 23 may be guided in its vertical travel by a pair of guide blocks mounted, for example, on a support plate connected to the frame 5. A piston 24 is mounted on the rod 21 and a piston 25 is mounted on the rod 22. The cylinders are provided with respective seals 26 and 27. In operation the motor 8 drives the two pistons rods first upwardly by a small amount to allow sealant base to flow from the well 1 9 into the cylinder 9 and to allow accelerator to flow from the reservoir 11 into the bore of the cylinder 10.Thereafter the motor 8 causes the pistons to move downwardly an equal amount to expel the respective materials from the outlets of the cylinders. Since the operating strokes of the cylinders are equal, the amounts of material expelled from each outlet will be in a fixed proportion determined by the ratio of the areas of the cylinder bores. A suitable ratio for use with common sealants is twelve parts of base to one part of accelerator. If it is desired to alter the ratio, this may be done by replacing one of the cylinders, preferably the smaller cylinder 10, with one of a different bore area. A pneumatic control device 28 is provided to control the operation of the motor 8 and may include a foot-operated switch and a quick exhaust valve. For example, the motor 8 may be a double acting cylinder controlled by a threeport spring return valve and afoot switch pilot valve.

in an alternative arrangement for use where no air supply is available the motor 8 may be replaced by an electric motor and control circuit.

In use the apparatus is pushed to the location where mixed sealant is required and connected to a suitable air supply. The reservoir 11 is then filled with accelerator through the filler opening 29. A container 1 of sealant base of the kind shown in Figure 1 is then taken and the upper lid removed.

The container is then inverted and placed on the rubber mat 1 7. The sealant base is so viscous that no significant amount of material will flow out of the container during this operation whilst the other lid is still fitted, although for less viscous material this operation may be assisted by placing a plastic sheet over the opening in the container and drawing it out after the container is positioned on the mat 17. The securing devices 18 are then tightened to clamp the container to the support plate 16 and to form a seal. Thereafter, the other lid 4 which is now on the upper end of the container 1 is removed and a heavy follower plate 30 is placed on the sealant material to cause it to flow downwardly.The valve 12 is then set to open to the mixing chamber and the motor 8 operated as many times as necessary to cause mixed sealant to emerge from the delivery tube 1 5.

Mixed sealant may then be delivered whenever required and in whatever quantities are required simply by operating the foot switch of the control device 28. After use when it is desired to purge the mixer and delivery tube 15 of mixed sealant, the valve 1 2 is operated to return accelerator to the reservoir and the motor 8 operated again-one or two times until pure sealant base emerges from the tube 1 5. The pure sealant base is generally a different colour from the mixed sealant and it is easy to tell at the end of operations when pure sealant is delivered or at the beginning of operations when the mixed sealant is delivered.

Clearly the principles of the invention may be employed in a machine arranged to deliver a one - part sealant. In this case only the motor 8 and cylinder 9 would be required.

Claims (19)

1. In combination, a container having a removable lid at each end and containing a liquid to be dispensed, and apparatus adapted to releasably secure the container thereon, said apparatus including means for delivering said liquid downwards from the bottom of the container.

2. Apparatus as claimed in claim 1 wherein the container has a rim which has a diameter larger than the diameter of the rest of the container and including releasable securing means adapted to engage the rim.

3. Apparatus as claimed in claim 1 or 2, wherein the container has a rolled rim at each end and a lid on each end which is removable and replaceable.

4. A container and liquid delivering apparatus, substantially as hereinbefore described with reference to the accompanying drawings.

5. A method of delivering a liquid component, comprising providing the component in a container with a removable lid on each end, removing the lower lid to allow the delivery of the component downwardly, and removing the upper lid to provide a vent to allow the component to move downwardly out of the container.

6. A method as claimed in claim 5, wherein the downward movement is assisted by a follower plate placed on top of the component.

7. A method of delivering a liquid component, substantially as hereinbefore described with reference to the accompanying drawings.

8. A container for sealant or the like comprising a hollow cylinder with a rim at each end, and a removable lid closing each end and being a push fit whereby it may be removed and replaced.

9. A container as claimed in claim 8, wherein the cylinder is metal and formed with rolled rims which are each rolled outwardly beyond the circumference of the cylinder.

10. A container as claimed in claim 8 or 9, wherein the opening at each end of the cylinder is of the full width of the cylinder.

11. A container substantially as hereinbefore described with reference to the accompanying drawings.

12. Apparatus for metering and mixing in predetermined proportions two liquids, comprising means for receiving and releasably securing a container of a first said liquid, a reservoir for receiving the second said liquid, two cylinders and pistons disposed at a lower level than the container and reservoir respectively, the piston rods being connected to be driven together, and means for reciprocatingly driving the piston rods, the first cylinder having an inlet for receiving the first liquid from the container and an outlet for delivering a substantially fixed amount of the first liquid to a mixing chamber on each stroke of the piston rods, and the second cylinder having an inlet for receiving the second liquid from the reservoir and an outlet for delivering a predetermined quantity of said second liquid to the mixing chamber on each stroke of the piston rods.

13. Apparatus as claimed in claim 12, wherein a non-return valve is provided between the outlet of the first cylinder and the mixing chamber.

14. Apparatus as claimed in claim 12 or 13, wherein a manually operable valve is provided in the flow path of the second liquid.

1 5. Apparatus as claimed in claim 14, wherein the manually operable valve is a three-port valve arranged to direct the second liquid to the mixing chamber or to return it to the reservoir.

1 6. Apparatus as claimed in any of claims 12 to 1 5 wherein the piston rods and a driving rod are all rigidly interconnected by means of a connecting block.

17. Apparatus as claimed in any of claims 12 to 1 6 including a static mixer connected to receive the liquids from the mixing chamber and to deliver the mixture to an outlet.

18. Apparatus as claimed in claim 17, wherein the static mixer comprises a passage with a plurality of vanes disposed therein so as to force the liquids to travel a tortuous path during which they intermix.

19. Apparatus for metering and mixing two liquids, substantially as hereinbefore described with reference to the accompanying drawings.