Assembly for and Method of Dispensing a Liquid

Abstract

Assembly for dispensing a liquid, in particular a colorant for paint, comprising a container for holding a liquid, a pump, a valve, at least one dispense opening, and comprising or associated with a controller arranged to operate the pump and the valve to withdraw liquid from the container and to dispense liquid via the opening and to operate the pump and the valve to purge liquid from the pump to the container via the dispense opening.

Claims

1. An assembly for dispensing a liquid comprising: a container for holding a liquid, a pump, a valve, at least one dispense opening, and a controller to operate the pump and the valve to withdraw liquid from the container and to dispense liquid via the opening and to operate the pump and the valve to purge liquid from the pump to the container via the dispense opening.

2. The assembly according to claim 1, comprising at least one further dispense opening having a diameter different from a diameter of the first dispense opening, and wherein the controller is arranged to operate the pump and the valve to purge liquid from the pump to the container via the at least one further dispense opening.

3. The assembly according to claim 1, wherein the valve, in a first position, connects the container to the pump and, in a second or further position, connects the pump to the or a dispense opening.

4. The assembly according to claim 1, wherein the valve comprises a rotatable valve member and the dispense opening is/are disposed in the valve member.

5. The assembly according to claim 4, wherein the dispense openings are all located within 120°, of rotation of the valve member from each other.

6. The assembly according to claim 1, wherein the valve, in a further position, closes the pump and wherein the controller is arranged to establish whether the medium inside the pump is compressible or expandable.

7. The assembly according to claims 1, wherein the valve comprises a plurality of different openings and/or a variable opening and wherein the controller is arranged to establish whether flow resistance in the liquid over the opening(s).

8. The assembly according to claim 1, wherein the controller comprises a memory programmed to purge the dispense opening(s) and/or establish compressibility, expandability and/or flow resistance automatically.

9. The assembly according to claimsl, wherein the pump is a positive displacement pump.

10. An apparatus for dispensing a plurality of liquids, in particular colorants for paint, comprising a plurality of assemblies according to claim 1.

11. A method of dispensing a liquid, from an assembly comprising a container holding a liquid, a pump, a valve, and at least one dispense opening, the method comprising the steps of withdrawing liquid from the container and dispensing the liquid from the dispense opening, and characterised by purging liquid from the pump to the container via the dispense opening.

12. The method according to claim 11, wherein the assembly comprises a further dispense opening and wherein liquid is purged from the pump to the container via the further dispense opening.

13. The method according to claim 11, wherein the pump is closed by means of the valve and the method further comprises establishing the degree of compressibility or expandability of the liquid in the pump.

14. The method according to claim 11, further comprising varying an opening, between the pump and the container, generating a flow of the liquid through different openings and establishing flow resistance of the liquid through the different openings.

15. The method according to of claim 11, wherein purging the dispense opening and establishing compressibility, expandability and flow resistance is performed automatically.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The disclosed invention will be further explained with reference to the accompanying drawings in which presently preferred embodiments of the invention are shown schematically.

[0027] FIG. 1 is a perspective view of a part of a disclosed apparatus for dispensing viscous liquid.

[0028] FIG. 2 is cross-sectional side view of a disclosed valve assembly suitable for use in the apparatus of FIG. 1.

[0029] FIG. 3 is a partial detailed view of the valve assembly of FIG. 2.

[0030] FIG. 4 is a cross-sectional front view of the valve assembly as shown in FIG. 3.

[0031] FIGS. 5A and 5B show the same detail as FIG. 3 at different positions of the valve.

[0032] FIG. 6 shows part of a further embodiment comprising a different valve at seven positions.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0033] FIG. 1 illustrates the main parts of an example of an apparatus 1 for dispensing viscous liquids, such as colorants or dyes. This particular dispensing apparatus includes a turntable 2 rotatable about a vertical axis by means of a drive (not shown) in order to rotate the turntable 2 between discrete positions. On the turntable 2, there are mounted a plurality of assemblies 3, each comprising a container 4 for holding a liquid, pump 5, and a valve 6. Further details of the said apparatus and turntable are disclosed in U.S. Pat. No. 6,273,298, the contents of which are incorporated herein by reference.

[0034] FIGS. 2 to 4 show cross-sections of the pump 5 and valve 6. The pump 5 is a piston pump and includes a piston rod 5A provided with a piston 5B, disposed within a cylinder 5C of the pump 5, and an upper flange 5D. The flange 5D can be engaged by a controller 7 comprising an actuator (not shown) adapted to move the piston rod 5A and the piston 5B upwards during an intake stroke and downwards during a dispense stroke and an actuator (not shown) to operate the valve 6.

[0035] The controller 7 and actuators are stationary and arranged to position one of the assemblies 3 in line with the actuators in order to enable actuating the pump 5 and the valve 6. The cylinder 5C is mounted in the top part of a pump housing 9, which defines a cavity 10 and further includes an inlet channel 11 that is separated from the cavity 10 and adapted to be in fluid communication with a container 4 as shown in FIG. 1.

[0036] A valve housing 12, comprising a cover 12A, is attached to the lower part of the pump housing 9 by means of respective flanges 13, 14. A valve member, in this example a ball 15, is fitted in the housing 12 by means of two annular bearings 16A, 16B made of, e.g., a polymeric material, such as PTFE (Teflon). The valve member 15 is provided with a lever 17 with which it can be rotated about an axis A by means of the corresponding actuator. The valve housing 12 further defines a cavity 18 limited at its upper part by a first opening 19, through which the cavity 18 communicates with the cavity 10 of the pump housing 9. The valve housing 12 further includes a second opening 20 in its bottom part and a third opening 21 which communicates with the inlet channel 11 in the pump housing 9. The valve member 15 includes a first channel 22, extending along the axis A and communicating with the first opening 19 in the housing 12. It further includes at least two dispense openings, in this example in the form of outlet channels 23, 24, and an inlet channel 25, all radially extending from the first channel 22 to the circumference of the valve member 15. In this particular embodiment, the diameter of one of the outlet channels 23 is smaller than that of the other 24 and the diameter of both outlet channels 23, 24 is smaller than that of the inlet channel 25. Further, both of these diameters are smaller than the diameter of the outlet opening 20 in the housing 12 and the central axes of channels 23-25 are all located on the same sectional plane through the valve member 15 and are respectively, e.g., 30° C. and 100° C. apart.

[0037] FIGS. 2 to 4 show the intake position of the valve member, where the inlet channel 25 of the valve member 15 is in registry with the third opening 21 of the valve housing 12 and thus with the inlet channel 11. In other words, the container communicates with the cavity 10 in the pump housing 9 and the cylinder 7. In this position, the cavity 10 and cylinder 7 now can be filled with a desired amount of the liquid from the container by moving the piston 6 upwards over a desired or predetermined length. It is noted that, in this position, the inlet channel 22 temporarily serves as an outlet channel.

[0038] As soon as an appropriate amount of liquid is taken in, the valve member 15 can be rotated to the desired dispensing position, i.e., until the desired dispense channel 23, 24 is in register with the opening 20 in the housing and the piston 6 can be moved downwards to dispense a desired or predetermined amount from the said opening 20. If this amount of liquid is relatively small and/or the dosage should be precise, the relatively narrow output channel 23 is appropriate and, if this amount is relatively large and/or should be dispensed rapidly, the relatively wide output channel 24 is appropriate. Thus, the valve assembly enables the tailored and, if need be, precise and/or rapid dispensing of viscous liquids, without having to exchange the valve assembly or components of the valve assembly.

[0039] During purging, shown in FIGS. 5A and 5B, the valve member 15 is rotated until the desired dispense channel—the larger diameter channel in FIG. 5A and the smaller diameter channel in FIG. 5B—to be purged is in register with the third opening 22 in the housing 12, which communicates with container 4. In these positions, the piston 6 is moved downwards to purge a predetermined amount of liquid through the dispense channel back to the container 4.

[0040] FIG. 6 shows a further embodiment of a valve according to the present invention in seven positions. In this embodiment, the radial dispense channels 23, 24 are 108° apart and the intake channel 25 is positioned in between the dispense channels. The positions are, in succession, intake or return of liquid via the intake channel 25, purging the larger diameter dispense channel 24 by returning liquid to the container, purging the smaller diameter dispense channel 23 by returning liquid to the container, closing the pump from all suction and dispense openings and routes fluid, dispensing via the smaller diameter dispense channel 23, dispensing via the larger diameter dispense channel 24, and dispensing via the intake channel 25.

[0041] As a matter of course, the invention is not restricted to the above-disclosed embodiment and can be varied in numerous ways within the scope of the claims.