GB2118054A

GB2118054A - Dispensing device for a paint mixing machine

Info

Publication number: GB2118054A
Application number: GB08301829A
Authority: GB
Inventors: John William Blackwell
Original assignee: AULT AND WIBORG PAINTS Ltd
Current assignee: AULT AND WIBORG PAINTS Ltd
Priority date: 1982-01-23
Filing date: 1983-01-24
Publication date: 1983-10-26
Also published as: GB8301829D0; GB2118054B

Abstract

A dispensing device for use in a paint mixing machine comprises a pressure vessel having a lid 11 and a base 12 into which a storage container 9 containing base tinter can be placed. The vessel can be pressurised to force the tinter up a tube 18 depending into the container through a valve controlled outlet. Rotary stirring means may be provided to agitate the tinter before and during dispensing operation. The stirrer may be power driven by belt or chain. <IMAGE>

Description

SPECIFICATION Dispensing device for a paint mixing machine This invention relates to a dispensing device for use in a paint mixing machine, the dispensing device being utilised to dispense a quantity of socalled tinter into a receiving container from a storage container.

Paint mixing machines are known which comprise a plurality of storage containers for the tinters. The storage containers are mounted in a motorised rack support system which can be operated to bring a particular storage container to a dispensing station at which is located the receiving container. The receiving container is carried on a weighing device which provides a signal to the machine operator of the weight of the receiving container together with its contents.

With this form of machine the storage container at the dispensing station has to be tilted by hand to transfer tinter to the receiving container. This operation requires a good deal of skill on the part of the operator particularly when the quantity of tinter to be dispensed is small. The operation is made more difficult by the fact that the viscosities of the various tinters may not be the same.

The object of the invention is to provide a dispensing device for the purpose specified in a simple and convenient form.

According to the invention a dispensing device for the purpose specified comprises a pressure vessel into which in use, a storage container containing tinter can be placed, means for pressurising the interior of the vessel, an outlet tube depending in use, into the storage container and a valve controlled outlet connected to said tube.

An example of a dispensing device in accordance with the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a cut-away view of a pressure vessel, Figures 2, 3 and 4 are sectional side elevations of different forms of valve, and Figure 5 is a view similar to Figure 1 of a further example of a pressure vessel.

The dispensing device to be described forms part of a machine which includes a plurality of dispensing devices each of which is capable of dispensing a liquid base tinter into a receiving container.

Each dispensing device comprises a container 10 conveniently formed as a pressure vessel, having a detachable lid whereby a storage container 9 containing liquid base tinter, can be loaded therein respectively. The lid of the vessel mounts a stirring device which depends into the tinter in the container so that the tinter can be continuously stirred while the machine is in operation. As shown in Figure 1, the lid 11 of the vessel is of the same depth as the base 1 2 of the vessel the latter defining a lip to accommodate a sealing member secured on the lid. The sealing member establishes a seal between the two parts of the vessel.Part of the stirring device is indicated at 13 it including a shaft 14 mounting a toothed drive pulley 1 5 and a fork 1 6 to which a paddle (not shown), is connected. The puliey in the example engages a drive belt which is driven by a suitable motor not shown.

rh, shaft 14 is provided with an axial passage through which air can be supplied to the interior of the vessel. This supply is conveniently effected by an air delivery nozzle positioned at the dispensing rotation. The nozzle includes a piston/cylinder combination which can be energised when a vessel is at the dispensing station, to bring the nozzle into contact with the pulley to allow air flow into the vessel. The vessel may however be pressurised the whole time the machine is in operation.

Moreover each pressure vessel is provided with a discharge valve shown in dotted outline in Figure 1 at 17. The valve is mounted on the lid of the vessel and is connected to a depending tube 1 8 within the vessel. The lower end of the tube lies below the level of tinter in the container 9 carried in the vessel so that when the valve is opened and the vessel is pressurised, tinter will flow up the tube through the valve. The valve includes a valve body having a discharge opening which during dispensing of the tinter will lie directly over the receiving container. The valve is operated by a powered operator (not shown), the operator itself being electrically operated either directly or indirectly by a suitable control system.

A modified form of pressure vessel is seen in Figure 5 and this comprises a base portion 41 having a depth substantially equal to the depth of the vessel. A lid 42 is provided, this defining an annular recess to receive the edge of the base. The lid 42 defines a hollow depending boss 43 which mounts a bearing bush which provides support for a hollow rotary shaft 44. An internal lid 45 is mounted about the shaft 44 but is restrained against rotation by a depending spigot which extends downwardly from the lid 42 and locates in an aperture in the internal lid 45, the aperture being larger than the spigot to allow passage of air under pressure into a paint or tinter storage container 46. The internal lid 45 locates over the open upper end of the storage container 46 and can be clipped thereto by a pair oft lips 51 which can be engaged beneath the rim of the paint container.

The lid 42 is provided with clips whereby it can be secured to the base and it is also provided with an air inlet unit for connection to a source of air under pressure. The hollow shaft 44 extends through the lid 42 and carries driving member in the form of a toothed sprocket 48 which when the pressure vessel is in position on a support rack is engaged by a drive chain whereby .he shaft can be rotated. Within the paint container 46 the shaft carries a paddle unit 47 which effects stirring of the paint or tinter within the container 46.

Extending within the shaft 44 is a tube 49 which extends from adjacent the locker end of the paint container through the shaft, to a position above the sprocket 48 where it is secured in a mounting itself secured to the lid 42. The mounting incorporates a passage communicating with the tube the passage in use being connected to a valve which can be opened to allow tinter from the container 46 to flow up the tube 49 to an outlet.

An air seal 50 is provided between the shaft 44 and the boss 43 to prevent escape of air from the vessel and a paint seal is provided at the lower end of the shaft 44 for engagement with the tube.

The design of the valve is important since it is desirable that as soon as the valve is moved to the closed position, the supply of tinter through the valve should cease and that there should be no drips from the valve due to tinter disposed between the outlet of the valve and the valve surfaces. The latter is important from the point of view of the accuracy of dispensing the tinter and also because the tinter will in some cases contain volatile solvents which may evaporate leaving a deposit in or on the valve which will hinder the operation thereof.

In one example of the valve as shown in Figure 2 the valve has a tubular body 19 one end of which is adapted for connection to the tube within the pressurised vessel. Formed in the wall of the body is an aperture or outlet 20 defining the discharge opening and rotatable within the body is a cylindrical valve member 21. The valve member has a lateral drilling 22 which can by angular movement of the valve member, be brought into register with the aperture. In addition the valve member has a longitudinal drilling 23 which communicates at one end with the lateral drilling and at the other end with the aforesaid one end of the body. Conveniently the valve member has a part spherical end portion which bears against an insert 24 of complementary shape, disposed within the body, the insert having a central drilling to allow flow of tinter to the drillings in the valve member.The valve member is resiliently biased by a coiled compression spring 25, into contact with the insert, the spring having one end engaged upon a shoulder defined on the valve member and its other end engaging an end closure 26 for the other end of the body. An actuating rod 27 is coupled to the valve member and it extends through an aperture in the end closure. The projecting portion of the rod carries a radial arm 28 mounting a peg 29 which can be engaged by the operating member of the operator the latter in this case, being of the rotary type. The thickness of the wall of the body is arranged to be as small as possible so that when the valve member is moved to the closed position the stream of tinter will be sheared by the valve member and little if any tinter will cling to the wall of the aperture 20.Moreover, the aperture is flared outwardly to further reduce the possibility of tinter clinging to its wall.

An alternative form of valve shown in Figure 3, which instead of having an angularly movable valve member has an axially movable valve member 30, the valve member being in the form of a cylindrical plug biased as in the previous example, towards an insert 31 which in this case defines a truncated conical seating. The plug during axial movement under the action of the spring closes the aperture 20 in the wall of the body before the plug engages the seating. Again therefore the tinter stream is sheared by the valve member and little if any tinter will cling to the wall of the aperture. In this case the valve member must be pulled towards the left to open the valve and the exterior end of the rod is provided with an abutment 32 which can be engaged by a suitable shaped operating member of the operator.

A further form of valve is seen in Figure 4 and this includes a tubular stem 33 which carries a valve head 34 formed from paint resistant material and having a lateral drilling 35 which communicates with the interior of the stem. The stem carries a guide assembly 36 which guides the axial movement of a tubular member 37 which carries a pressure pad 38 at its open end. Located between the pressure pad and the valve head is a coiled compression spring 39 and formed in the tubular member 37 is an opening 40 which can be brought into register with the drilling 35 by movement of the tubular member against the action of the spring, to allow discharge of tinter into the receiving container. In this example the movement of the operating member is towards the vessel. Again a shearing action is obtained.

The space in the tubular member which contains the spring should be vented to allow rapid operation of the valve.

A further form of valve which has proved to be particularly suited for controlling the flow of paint or tinter is a double diaphragm type of valve having a pair of diaphragms connected to a valve stem. Air under pressure can be applied to one or the other outer surfaces of the diaphragms to effect displacement of the valve stem between the open position in which tinter can flow from a valve inlet to an outlet and to the closed position in which the flow is prevented. An advantage of this form of valve is that it can be arranged that the tinter is drawn back from the outlet by the action of one of the diaphragms thereby preventing any drips of tinter from the outlet. A simple changeover valve is used to control the operation of the valve and this can be operated by a solenoid. It is also possible to provide the outlet with different sizes of orifice so that with a common container pressure the flow rates through the outlet can be made substantially the same even through the viscosities of the tinters may differ.

The machine is intended to be used to make up paint of a particular colour for example paint for use when respraying parts of vehicles. Such paint usually comprises a number of base tinters which are mixed together in predetermined amounts according to the desired colour. For example it may be required to mix 200 grams of one base tinter with 5 grams of another base tinter. Each paint colour will have a recipe giving the quantities of the various base tinters by weight to produce a given volume of the paint which is required.

Knowing the volume of the paint required it is possible to determine the weights of the various base tinters which are required to be put into the receiving container carried by the weighing device.

The viscosities of the base tinters will depend upon the temperature and the viscosities may vary even if they are all at the same temperature.

Although some compensation may be achieved by varying orifice size or even air pressure, it would be difficult if not impossible to adjust the flow rates through the respective valves so that the quantity could be directly related to the time the respective valve was open and hence a weighing technique is employed.

Claims

1. A dispensing device for use in a paint mixing machine, the device comprising a pressure vessel into which in use, a storage container containing tinter can be placed, means for pressurising the interior of the vessel, as outlet tube depending in use, into the storage container and a valve controlled outlet connected to said tube.

2. A device according to Claim 1 in which the outlet is formed in the wall of a thin walled tubular member.

3. A device according to Claim 2 in which the outlet is flared outwardly.

4. A device according to Claim 2 or Claim 3 including means engaging the inner surface of said tubular member whereby the column of tinter flowing through said outlet is sheared upon relative movement of said means and said member to prevent flow of tinter through the outlet.

5. A device according to Claim 2 or Claim 3 in which said tubular member is adapted at one end for connection to the pressure vessel, said one end of the tubular member communicating with said tube.

6. A device according to Claim 5 including an insert located at said one end of the tubular member, a valve member movable in the tubular member and having a surface shaped for cooperation with a surface defined on the insert, resilient means acting on the valve member to urge said surfaces into engagement with each other and an actuating rod connected to said valve member, said actuating rod extending through an end closure for the other end of the tubular member.

7. A device according to Claim 6 in which said surfaces are of part spherical form, said valve member having a lateral drilling positioned for communication with said outlet upon angular movement of the valve member, said lateral drilling communicating with said one end of the tubular member.

8. A device according to Claim 6 in which surface on the insert defining a truncated conical seating, the valve member being movable axially away from said seating to expose said outlet to the one end of the cylinder.

9. A device according to Claim 2 or Claim 3 including a tubular stem adapted to be mounted on the vessel so that the interior of the stem communicates with said tube, a valve head fixed to the stem and defining a lateral drilling communicating with the interior of the stem, said tubular member being slidable over said valve head to align said outlet with said drilling, and resilient means acting between said tubular member and the valve head.

10. A device according to Claim 9 including a guide assembly acting to guide the relative movement of the stem and tubular member.

11. A device according to any one of the preceding claims in which the pressure vessel includes a detachable lid, and a stirring device carried by said lid.

12. A device according to Claim 11 in which said stirring device comprises a drive shaft supported in a bearing defined by said lid, a paddle unit carried by said shaft and which is located in use, within the storage container, seal means acting to prevent escape of air from the interior of the vessel through said bearing, a drive member carried by said shaft exterior of the lid for engagement in use with a flexible drive member whereby the paddle can be rotated, an internal lid located about the drive shaft and adapted to locate over the open end of the storage container, and means preventing rotation of said internal lid by the drive shaft.

1 3. A device according to Claim 12 in which said shaft is hollow and said tube extends within said shaft, seal means being provided between the tube and the internal surface of the shaft to prevent flow of tinter between the shaft and the tube.

14. A device according to Claim 12 or Claim 13 in which the means preventing rotation of the internal lid comprises a spigot depending from the first mentioned lid, said spigot extending within an aperture in the internal lid, the aperture being larger in size than the spigot to allow air under pressure to enter the storage container.

1 5. A device according to Claim 1 2 including a clip carried by the internal lid which can be engaged beneath the rim of the container to secure the internal lid thereto.

1 6. A device according to Claim 1 in which the valve controlling said outlet comprises a double diaphragm valve having associated therewith a changeover control valve whereby air under pressure can be applied to one or the other diaphragm to effect opening or closing of the valve, said valve having the characteristic that tinter is drawn back from the outlet upon closure of the valve.

17. A Dispensing device for use in a paint mixing machine comprising the combination and arrangement of parts substantially as hereinbefore described with reference to the accompanying drawings.