Method of cleaning a nozzle

Abstract

The invention relates to a method of cleaning a nozzle in a valve (5) for dispensing a liquid, in particular a viscous liquid, such as a colorant or pigment for paints, by means of a cleaning implement, preferably a brush (10), comprising the steps of cleaning the implement (10) with a cleaning liquid (12), allowing the implement (10) to dry, and cleaning the nozzle with the dried implement (10).

Description

Technical Field

[0001] The invention relates to a method of cleaning a nozzle in a valve for dispensing a liquid, in particular a viscous liquid, such as a colorant or pigment for paints, by means of a cleaning implement, preferably a brush. The invention also relates to an apparatus for dispensing a plurality of liquids, in particular viscous liquids, such as colorants and pigments for paints, comprising a support, such as a turntable or a linear table, a plurality of containers for a liquid, mounted on the support and provided with a pump and a valve for dispensing the liquid from the container via a nozzle in the valve, an implement, preferably a brush, for cleaning the nozzle, and a reservoir for supplying a cleaning liquid to the implement.Background Art

[0002] EP 1 990 102 relates to a dispensing device for dispensing a number of liquids, comprising a movable support, a dispensing assembly supported on said support, each dispensing assembly comprising a liquid reservoir and a pump having a dispensing opening, a stationary pump actuation device configured to cooperate with a pump, and a stationary cleaning device for cleaning a dispensing opening positioned at a cleaning location. Said cleaning device comprises a cleaning brush comprising a central portion rotatable about an axis of rotation and a number of bristles extending from said central portion, wherein said bristles are arranged on only a part of the circumference of said central portion so that in a rotational rest position of said cleaning brush none of said bristles contacts said dispensing opening when positioned in said cleaning location.

[0003] It is an object of the present invention to provide an improved dispenser, in particular one that enables more accurate dispensing and / or dispensing of smaller droplets, e.g. droplets equal to or smaller than 0.04 ml.Summary of the disclosure

[0004] To this end, the method according to the present invention comprises the steps as defined in claim 1.

[0005] In current practice, the brush that is used to clean the nozzles in dispensers for colorants or pigments for paints is wetted permanently or at least just prior to cleaning the nozzles. A typical brush for cleaning such nozzles is bristled, rotatable and / or cylindrical and, during cleaning, the bristles in the upper part of the brush contact the nozzle located above it, while its lower bristles extend in, e.g. rotate through, a cleaning liquid in a reservoir located below the brush. Cleaning the nozzle(s) with a wetted brush leaves the nozzle(s) wet after a cleaning cycle and during subsequent dispensing of the liquid from the nozzle. It was found that the presence of cleaning liquid on or near a nozzle negatively affects the accuracy and / or reproducibility of dispensing very small amounts from the nozzle. It was also found that nozzles can be effectively cleaned with a dry brush and that a nozzle thus cleaned is capable of more accurately and / or reproducibly dispensing small amounts of liquid, e.g. amounts equal to or smaller than 0.04 millilitre (ml) or even equal to or smaller than 0.03 ml, and thus e.g. dispense amounts small enough and accurately enough to mix samples (testers).

[0006] In an embodiment, the method comprises the step of dispensing the liquid from the nozzle that has been cleaned with the dried implement, preferably dispensing an amount of the liquid that is equal to or smaller than 0.5 ml, preferably equal to or smaller than 0.04 ml, preferably equal to or smaller than 0.03 ml, preferably equal to or smaller than 0.015 ml.

[0007] The nozzle is cleaned with the dried implement a plurality of times, e.g. at least 20 times or at least 50 times, and / or a plurality of nozzles, e.g. all nozzles of a dispenser comprising a plurality, e.g. sixteen or thirty-two, assemblies of a container, pump, and valve, are cleaned with the dried implement, before the implement is again cleaned with the cleaning liquid.

[0008] In a refinement, after cleaning the nozzle a plurality of times, e.g. at least 20 times or at least 50 times, with the dried implement and / or cleaning a plurality of nozzles with the dried implement, the implement is wetted with the cleaning liquid and cleaned and / or the nozzle or nozzles are wetted with the cleaning liquid and cleaned by means of the implement.

[0009] In an example, the implement is not wetted or cleaned and remains dry during the day, e.g. during business hours, or during a predetermined number of nozzles cleaned, and subsequently the implement and preferably also the nozzle(s) are wetted and cleaned during the night, e.g. after / outside business hours, or after a predetermined number of nozzles have been cleaned. This procedure facilitates cleaning the nozzle e.g. following a period of limited or no use or a prolonged maintenance interval.

[0010] In a further refinement, after wetting, residues in the implement or on or near the nozzle(s) are allowed to dissolve in the cleaning liquid during a predetermined time, e.g. for at least two minutes, preferably at least five minutes, before the implement and / or the nozzle(s) are cleaned.

[0011] In an embodiment, cleaning liquid is removed from one or more nozzles by means of a dry implement.

[0012] In another embodiment, which requires less moving parts, the cleaning liquid is applied, preferably jetted, sprayed or dripped, onto a top or side section of the implement.

[0013] In another embodiment, the cleaning liquid contains an agent that promotes the settling of material cleaned off the nozzle(s), such as residues of colorant or pigment removed from the nozzle (s) .

[0014] The invention further relates to an apparatus as defined in claim 9.

[0015] In an embodiment, the apparatus comprises an actuator to supply cleaning liquid to the implement, e.g. via a conduit and one or more nozzles directed towards the implement, and / or immerse at least a part of the implement in the cleaning liquid.

[0016] In another embodiment, the implement is located in or above the reservoir, and the reservoir comprises an actuator, e.g. a block or float movable by a motor, e.g. a stepper motor, to raise and lower the level of cleaning liquid in the reservoir to, respectively, immerse and wet the implement or prevent the implement from contacting the cleaning liquid.

[0017] The controller is arranged to operate the implement to clean the nozzle or nozzles a plurality of times, e.g. at least 20 times or at least 50 times, while it is dry and to then operate the implement and / or the actuator to wet and clean the implement and preferably also the nozzle(s) with the cleaning liquid.

[0018] In a refinement, the controller is configured to allow, after the implement and / or the nozzles have been wetted, residues in the implement and / or on or near the nozzle(s) to dissolve in the cleaning liquid during a predetermined time, e.g. for at least two minutes, preferably at least five minutes, and then operate the implement and / or the actuator to clean the implement, e.g. against a pressure roller, and / or the nozzle(s).

[0019] In an embodiment, the controller is configured to wet the implement and all nozzles or at least the nozzles that have been used during the last cleaning, allow residues to dissolve in the cleaning liquid, wet the nozzles again to remove the cleaning liquid containing residues from the nozzles, dry the implement, and clean the liquid from the nozzles with the dried implement.

[0020] In another embodiment, a plurality of the valves comprise a housing and a valve member rotatably fitted in the housing and comprising a nozzle configured such that the liquid will be dispensed directly from the valve member, i.e. without an additional downstream channel, spout, or the like, and / or a plurality of the nozzles has a diameter equal to or smaller than 2 mm, preferably equal to or smaller than 1.5 mm.

[0021] In an embodiment, the controller comprises a processor and a memory and is configured to receive data on the use of the nozzle(s), e.g. the number of dispenses and / or the amount(s) dispensed, to process such data, and to operate one or more drivers that cause the implement and, if required, the nozzle(s) to be wetted.

[0022] Although a brush is the preferred cleaning implement, alternative implements include a roller, sponge or cloth, which are preferably cylindrical and / or rotatable.

[0023] Within the framework of the present invention the term "liquid" is defined as any flowable material that comprises a liquid phase and thus includes suspensions and emulsions. Colorants often contain high density pigments or particles suspended in (instable) liquid binder / solvent solutions.Brief description of the drawings

[0024] The disclosed dispenser and cleaning device will be further explained with reference to the accompanying drawings in which a presently preferred embodiment of the invention is shown schematically. Details, that are not necessary for understanding the present invention, may have been omitted. Figure 1 is a perspective view of a dispensing for a plurality of colorants and pigments for paints. Figure 2 is show detail of the dispenser shown Figure 1, including a rotary brush. Figures 3 and 4 are side views of a first embodiment of the present invention comprising a rotary brush and a reservoir configured for immersing a lower section of the brush in a cleaning liquid. Figure 5 is a side view of a second embodiment of the present invention comprising and a nozzle configured to spray a cleaning liquid on an lower section of the brush. Detailed description of the presently preferred embodiments

[0025] Figure 1 shows a dispenser 1 for a plurality of colorants and / or pigments for paints, comprising a support, in this example a turntable 2, and a plurality of containers 3 for a liquid mounted on the support. Each container is connected to an assembly of a pump, in this example a piston pump 4, and a valve 5 for dispensing the liquid from the container via a nozzle in the valve. The assemblies are mounted on the turntable at equidistant positions along its circumference.

[0026] In this example, the valves comprise a rotatable valve member, such as a ball of cylinder, and the nozzle is defined in the valve member, e.g. as a radial channel, preferably having a diameter equal to or smaller than 2 mm. The liquid is dispensed downwards (following the direction of gravity) and directly from the valve member.

[0027] The dispenser comprises, in its front, a door 6 containing actuators for operating the pump and valve of the assembly directly behind it. By turning the table, a selected assembly of pump and valve can be aligned with the actuators in the door and liquid can be withdrawn from the respective container and dispensed in a receptacle (not shown) on a table beneath the valve.

[0028] Further information regarding suitable dispensers and procedures for driving the various components, are disclosed in, for instance, European patent applications EP 800 858, EP 1 492 970, EP 1 688 652, and EP 2 198 950.

[0029] As shown in Figure 2, a rotary brush 10 is located below the turntable 2, such that its bristles contact the nozzle of the valve directly above it and the nozzle can be cleaned by rotating the brush. Further, the brush is located in or above a reservoir 11 containing cleaning liquid 12. In general, suitable cleaning liquids include water, alcohol, liquid hydrocarbons, and mixtures of water and alcohol or soap. The liquid can contain additives, such as agents that promote the settling of material cleaned off the nozzle(s).

[0030] In the embodiment shown in Figures 3 and 4, the reservoir 11 is provided with a block 13 or float that is movable between two positions, a lowered positon (Figure 3) and a raised position (Figure 4). In the lowered positon (Figure 3), the block causes the level of the cleaning liquid 12 in the reservoir to rise, such that a lower section of the brush is immersed in the liquid and the brush and, upon rotation of the brush, the nozzle are wetted and cleaned with the liquid. In the raised position (Figure 4), the block causes the level of the cleaning liquid in the reservoir to drop, such that contact between the brush and the cleaning liquid is prevented. In this latter position, the brush can be dried, e.g. through evaporation and, if accelerated drying is required, by forced convection and / or a pressure roller 14. Further, in this position, the brush, once dried, will remain dry and, in consequence, the nozzles are clean with a dry brush.

[0031] The embodiment shown in Figure 5 comprises one or more jets 15 to wet the brush 10. The jets are supplied with cleaning liquid from the reservoir 11 by means of a conduit 16 and a pump 17 and directed to a top section of the brush. When the pump is deactivated, the brush can be dried.

[0032] It was found that the nozzles can be effectively cleaned with a dry brush and a nozzle thus cleaned is capable of more accurately and / or reproducibly dispensing small amounts of liquid, e.g. amounts equal to or smaller than 0.04 millilitre (ml) or even equal to or smaller than 0.03 ml, and thus e.g. dispense amounts small enough and accurately enough to mix samples (testers).

[0033] The invention is not restricted to the embodiments described above and can be varied in numerous ways within the scope of the claims. For example, the level of the cleaning liquid in the reservoir, at least at the location of the brush, can be adjusted by simply tilting the reservoir.

Claims

1. Method of cleaning a nozzle in a valve (5) for dispensing a liquid, in particular a viscous liquid, such as a colorant or pigment for paints, by means of a cleaning implement, preferably a brush (10), wherein a reservoir (11) is configured to supply a cleaning liquid (12) to the implement (10); wherein a controller is configured to operate the implement (10) and / or the reservoir (11) and comprises a processor and a memory, which controller is configured to receive data on the use of the nozzle, to process said data, and to operate an actuator (13; 17) to wet the implement; wherein the controller is further configured to wet the implement (10) with the cleaning liquid (12) from the reservoir, to allow the implement (10) to dry, and to clean the nozzle of one or more of a plurality of containers with the dried implement (10), the method comprising the steps of: cleaning the implement (10) with the cleaning liquid (12); allowing the implement (10) to dry, and cleaning the nozzle with the dried implement (10), wherein the nozzle is cleaned with the dried implement (10) a plurality of times and / or a plurality of nozzles are cleaned with the dried implement (10), before the implement (10) is again cleaned with the cleaning liquid.

2. Method according to claim 1, comprising the step of dispensing the liquid from the nozzle that has been cleaned with the dried implement (10).

3. Method according to claim 2, comprising dispensing an amount of the liquid that is equal to or smaller than 0.5 ml, preferably equal to or smaller than 0.04 ml, preferably equal to or smaller than 0.03 ml, preferably equal to or smaller than 0.015 ml.

4. Method according to any one of the preceding claims, wherein, after cleaning the nozzle a plurality of times with the dried implement (10) and / or cleaning a plurality of nozzles with the dried implement (10), the implement (10) is wetted with the cleaning liquid (12) and cleaned and / or the nozzle or nozzles are wetted with the cleaning liquid (12) and cleaned by means of the implement (10).

5. Method according to claim 4, wherein, after wetting, residues in the implement (10) or on or near the nozzle(s) are allowed to dissolve in the cleaning liquid (12) during a predetermined time before the implement (10) and / or the nozzle(s) are cleaned.

6. Method according to any one of the preceding claims, wherein the cleaning liquid (12) is removed from one or more nozzles by means of a dry implement (10).

7. Method according to any one of the preceding claims, wherein the cleaning liquid (12) is applied, preferably jetted, sprayed or dripped, onto a top or side section of the implement (10).

8. Method according to any one of the preceding claims, wherein the cleaning liquid (12) contains an agent that promotes the settling of material cleaned of the nozzle(s).

9. Apparatus (1) for dispensing a plurality of liquids, in particular viscous liquids, such as colorants and pigments for paints, comprising a support, such as a turntable (2) or a linear table, a plurality of containers (3) for a liquid, mounted on the support (2) and provided with a pump (4) and a valve (5) for dispensing the liquid from the container (3) via a nozzle in the valve (5), an implement (10) for cleaning the nozzle, a reservoir (11) for supplying a cleaning liquid (12) to the implement (10), an actuator (13, 17) and a controller for operating the implement (10) and / or the reservoir (11) and comprising a processor and a memory, which controller is configured to receive data on the use of the nozzle, to process said data, and to operate the actuator, which controller is further configured to wet the implement (10) with the cleaning liquid (12) from the reservoir, to allow the implement (10) to dry, and to clean the nozzle of one or more of the plurality of containers with the dried implement (10), wherein the controller is arranged to operate the implement (10) to clean the nozzle of one or more of the plurality of containers a plurality of times while it is dry and to then operate the implement (10) and / or the actuator (13; 17) to wet and clean the implement (10).

10. Apparatus (1) according to claim 9, comprising an actuator (13; 17) to supply cleaning liquid (12) to the implement (10) and / or immerse at least a part of the implement (10) in the cleaning liquid (12).

11. Apparatus (1) according to claim 10, wherein the implement (10) is located in or above the reservoir (11), and the reservoir (11) comprises an actuator (13) to raise and lower the level of cleaning liquid (12) in the reservoir (11) to, respectively, wet the implement (10) or prevent the implement (10) from contacting the cleaning liquid (12).

12. Apparatus (1) according to any one of the claims 9-11, wherein the controller is arranged to operate the implement (10) and / or the actuator (13; 17) to wet and clean also the nozzle(s) with the cleaning liquid (12).

13. Apparatus (1) according to claim 12, wherein the controller is configured to allow, after the implement (10) and / or the nozzles have been wetted, residues in the implement (10) and / or on or near the nozzle(s) to dissolve in the cleaning liquid (12) during a predetermined time and then operate the implement (10) and / or the actuator (13; 17) to clean the implement (10) and / or the nozzle(s).

14. Apparatus (1) according to any one of the claims 9-13, wherein a plurality of the valves (5) comprise a housing and a valve member rotatably fitted in the housing and comprising a nozzle configured such that the liquid will be dispensed directly from the valve member and / or wherein a plurality of the valves has a nozzle with a diameter equal to or smaller than 2 mm, preferably equal to or smaller than 1.5 mm.

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