阅读说明：本技术 固体着色剂分配装置和包括该装置的着色机 (Solid colorant dispensing device and tinting machine comprising such a device ) 是由 P·P·M·汤姆马森 J·霍夫曼 J·J·E·惠宁 于 2020-03-05 设计创作，主要内容包括：本发明涉及一种固体着色剂分配装置(1),用于以时间控制的方式分配成剂量的固体球形着色剂颗粒(2),所述分配装置包括供应容器(3),该供应容器(3)具有喷嘴(5),该喷嘴(5)用于分配具有数量平均粒径和数量粒径分布的所述颗粒,其中,所述颗粒的所述数量粒径分布的标准偏差与所述数量平均粒径的比小于25％。所述喷嘴包括具有直径(7)的分配出口(6),所述直径(7)将所述颗粒的所述数量平均粒径考虑在内。所述分配装置包括控制组件(8),该控制组件(8)用于通过考虑所述颗粒的所述特性以及所述喷嘴(5)的所述出口的所述直径,控制所述颗粒的剂量的分配。本发明还涉及一种包括所述固体着色剂分配装置的着色机。(The invention relates to a solid colorant dispensing device (1) for dispensing in a time-controlled manner doses of solid spherical colorant particles (2), comprising a supply container (3), which supply container (3) has a nozzle (5), which nozzle (5) serves for dispensing the particles with a number average particle diameter and a number particle diameter distribution, wherein the ratio of the standard deviation of the number particle diameter distribution of the particles to the number average particle diameter is less than 25%. The nozzle comprises a dispensing outlet (6) having a diameter (7), the diameter (7) taking into account the number average particle size of the particles. The dispensing device comprises a control assembly (8), which control assembly (8) is adapted to control the dispensing of a dose of the particles by taking into account the characteristics of the particles and the diameter of the outlet of the nozzle (5). The invention also relates to a tinting machine comprising said solid colorant dispensing device.)

1. A solid colorant dispensing device (1) configured to dispense at least one dose of solid spherical colorant particles (2) in a time-controlled manner, the solid colorant dispensing device (1) comprising:

-a supply container (3), said supply container (3) comprising a free end portion (4), said free end portion (4) being provided with a nozzle (5), which nozzle (5) is configured and arranged to dispense said at least one dose of solid spherical colorant particles (2) during operation of said solid colorant dispensing device (1), said solid spherical colorant particles (2) having the following properties:

-a number average particle size; and

-a number particle size distribution, wherein the ratio of the standard deviation of the number particle size distribution to the number average particle size of the solid colorant particles is less than 25%, preferably less than 22%, more preferably less than 20%, wherein the particle size analysis-image analysis method-first part according to ISO13322-1: 2004: a static image analysis method, using an Onchio particle size particle shape analyzer to determine the number particle size distribution by light scattering and full-automatic image analysis;

the nozzle (5) comprises a dispensing outlet (6) having a diameter (7), the diameter (7) taking into account the number average particle size of the solid spherical colorant particles (2); and is

Characterized in that said solid colorant dispensing device (1) comprises:

-a control assembly (8), which control assembly (8) is configured and arranged to control the dispensing of the at least one dose of solid spherical colorant particles (2) in a time-controlled manner by taking into account the characteristics of the solid spherical colorant particles (2) and the diameter (7) of the dispensing outlet (6) of the nozzle (5).

2. The solid colorant dispensing device (1) according to claim 1, wherein the control assembly (8) comprises a solenoid (9), the solenoid (9) comprising a spring-loaded plunger (10), wherein the spring-loaded plunger (10) is configured and arranged with respect to the dispensing outlet (6) of the nozzle (5) when the solenoid (9) is in an inactive state to prevent the nozzle (5) from dispensing solid spherical colorant particles (2), and the spring-loaded plunger (10) is configured and arranged with respect to the dispensing outlet (6) of the nozzle (5) when the solenoid (9) is in an active state to allow the nozzle (5) to dispense solid spherical colorant particles (2).

3. The solid colorant dispensing device (1) according to claim 2, wherein the spring-loaded plunger (10) of the solenoid (9) is arranged such that a longitudinal centerline (11) of the spring-loaded plunger (10) is oriented transversely to a longitudinal centerline (12) of the nozzle (5).

4. The solid colorant dispensing device (1) according to claim 2 or 3, wherein the spring-loaded plunger (10) has a free end (13), the free end (13) being arrangeable in relation to the dispensing outlet (6) of the nozzle (6) for controlling the dispensing of the solid spherical colorant particles (2), wherein the free end (13) has an outer circumference (14), the outer circumference (14) having a shape configured to: when the free end (13) partially obstructs the dispensing outlet (6), a uniform flow of the solid spherical colorant particles (2) dispensed is ensured.

5. The solid colorant dispensing device (1) according to any one of the preceding claims, wherein a detection unit (16) is provided, which detection unit (16) is configured and arranged to determine a current inventory (17) of solid spherical colorant particles (2) in the supply vessel (3) and to provide a detection signal corresponding to the determined current inventory (17) to the control assembly (8).

6. The solid colorant dispensing device (1) according to any one of the preceding claims, wherein the supply container (3) comprises a first portion (18) having the free end portion (4) and a second portion (20) having an end portion (21), the free end portion (4) being provided with the nozzle (5), an end portion (21) of the second portion (20) being in open communication with an end portion (22) of the first portion (18) arranged opposite the nozzle (5), thereby providing a transition (19) between the second portion (20) and the first portion (18), the first portion (18) has a tapered inner wall (23), the tapered inner wall (23) being arranged at an angle (a) in the range of 15-55 degrees with respect to a longitudinal centre line (24) of the first portion (18), preferably the angle (a) equals 30 degrees.

7. The solid colorant dispensing device (1) according to claim 6 as dependent on claim 5, wherein the control assembly (8) is configured to set a dispensing time interval during which the solenoid (9) switches from the inactive state to the active state and back to the inactive state to allow the nozzle (5) to dispense a dose of solid spherical colorant particles (2) taking into account at least the diameter (7) of the dispensing outlet (6) of the nozzle (5), the angle (a) of the tapered inner wall (23) of the first portion (18) of the supply vessel (3), the current inventory (17) of solid spherical colorant particles (2) in the supply vessel (3), and a response time of the solenoid (9), wherein the response time of the solenoid (9) is dependent on receiving a switching signal from the control assembly (8) to switch between the inactive state and the active state.

8. The solid colorant dispensing device (1) according to any one of claims 2-7, wherein an overflow compartment (26) is provided, the overflow compartment (26) being configured and arranged with respect to the dispensing outlet (6) of the nozzle (5) to receive solid spherical colorant particles (2) dispensed by the nozzle (5) as a result of displacing the spring-loaded plunger (10) in response to switching the solenoid (9) from the active state to the inactive state.

9. The solid colorant dispensing device (1) according to any one of the preceding claims, wherein a vibration unit (27) is provided, which vibration unit (27) is configured and arranged to allow the supply container (3) to vibrate at a frequency in the range of 0-55Hz during operation of the solid colorant dispensing device (1).

10. The solid colorant dispensing device (1) according to any one of the preceding claims, wherein a replaceable cartridge (28, 39) containing solid spherical colorant particles (2) is provided, the replaceable cartridge (28, 39) being associated with the supply container (3) so as to provide an inventory of solid spherical colorant particles (2) to the supply container (3) and to allow automatic replenishment of the inventory in the supply container (3) with solid spherical colorant particles (2) from the replaceable cartridge (28, 39) in response to dispensing of at least one dose of solid spherical colorant particles (2) via the nozzle (5) until the replaceable cartridge (28, 39) is empty.

11. The solid colorant dispensing device (1) according to any one of the preceding claims, wherein the number average particle diameter of the solid spherical colorant particles (2) is in the range of 400-1400 μ ι η, preferably in the range of 500-1300 μ ι η, more preferably in the range of 600-1000 μ ι η.

12. The solid colorant dispensing device (1) according to any one of the preceding claims, wherein the solid spherical colorant particles (2) comprise 30-97 wt% pigment, less than 5 wt% solvent and 3-40 wt% surfactant, wherein wt% is related to the total weight of the solid spherical colorant particles (2).

13. The solid colorant dispensing device (1) according to any one of the preceding claims, wherein the dispensing outlet (6) of the nozzle (5) has a diameter (7) in the range of 5-15 mm.

14. The solid colorant dispensing device of any of claims 2-13, wherein the spring-loaded plunger has a stroke (15) in the range of 5mm-16 mm.

15. A tinting machine (29) configured to tint a base coating composition (30) with at least one dose of solid spherical colorant particles (2), the at least one dose of solid spherical colorant particles (2) being dispensed in a time-controlled manner by at least one solid colorant dispensing device (1) according to any preceding claim, the tinting machine (29) comprising:

-a receiving space (31) configured and arranged to receive a paint container (32) containing the base paint composition (30), the base paint composition (30) to be pigmented with the at least one dose of solid spherical colorant particles (2);

-a guide (33) configured and arranged to guide the at least one dose of solid spherical colorant particles (2) dispensed by the at least one solid colorant dispensing device (1) into the coating material container (32);

-a main control assembly (34) configured and arranged to communicate with the control assembly (8) of the at least one solid colorant dispensing device (1) to control the dispensing (2) of the at least one dose of solid spherical colorant particles by the at least one solid colorant dispensing device (1).

Technical Field

The present invention relates to a solid colorant dispensing device configured to dispense at least one dose (one charge) of solid spherical colorant particles in a time-controlled manner. The invention also relates to a tinting machine configured to tint a base coating composition with at least one dose of solid spherical colorant particles dispensed in a time-controlled manner by at least one solid colorant dispensing device according to the invention.

Background

Paint and stain manufacturers typically dispense small amounts of pre-mixed paints and stains of popular colors. To meet consumer demand and to be able to match existing painted or tinted surfaces, manufacturers typically also dispense a set of tintable paints and several concentrated colorants. These are combined at the end point of sale using a colorant dispensing device and shaker mixing equipment to produce small batches of custom colored coating in a larger color array than the limited color array available in the pre-mix product.

Basically, colorant dispensing devices known in the art are configured to dispense liquid colorants or solid colorants. The present invention is directed to a colorant dispensing device configured to dispense solid colorant particles.

Known solid colorant dispensing devices typically use a weight measurement of solid colorant particles to color the base coating composition. Gravimetric metering may include calculating the mass of the solid colorant particles to be metered using a mathematical equation and determining the mass of the solid colorant particles using a scale.

The disadvantage of the gravimetric metering of solid colorant particles is that it is a rather delicate process, especially when small amounts of solid colorant particles are to be metered. In this case, small changes in the environment (e.g. vibrations or air turbulence) may lead to serious weighing errors. Thus, it is possible to obtain pigmented or colored coating compositions that do not meet the required color specifications.

Another disadvantage of gravimetric metering of solid colorant particles is that the particles of different solid colorants must be metered sequentially because each individual particle of solid colorant must be weighed individually. Thus, the use of gravimetric metering to prepare a coloured coating composition involving particles of different solid colourants can be quite complex and expensive, as it requires considerable hardware, such as one balance and several containers, and it is quite time consuming, as precise metering is to be achieved using a stepwise principle involving multiple weighing. Furthermore, gravimetric metering of large amounts of solid colorants requires first coloring in a separate container, since the balance cannot withstand a large container containing the base coating composition to be colored. Due to the weight limitations imposed by the balance, gravimetric metering of large quantities of solid colorants needs to be performed in multiple steps.

US patent application US2017/0051151a1 discloses a testing device configured for testing volumetric metering of solid colorant particles. The testing apparatus includes a vessel or container having an opening for charging the solid colorant particles. The opening can be opened or closed by a plunger that can move up and down. By moving the plunger upwards, the feeding of the solid colorant granules through the opening under the influence of gravity is started for a determined period of time. When the plunger moves downward, the opening closes and the feed of solid colorant particles stops.

The solid colorant particles have a number average particle size and a number particle size distribution, wherein the ratio of the standard deviation of the number particle size distribution to the number average particle size of the solid spherical colorant particles is less than 25%, wherein the ratio of the number particle size distribution to the number average particle size is determined according to "ISO 13322-1:2004, particle size analysis-image analysis method-part one: static image analysis method ", the number particle size distribution was determined by light scattering and fully automated image analysis using an oerio particle size particle shape (occio ZEPHYR ESR) analyzer.

A disadvantage of the volumetric metering of solid colorant particles using the test device according to US2017/0051151a1 is that it does not allow volumetric metering of solid colorant particles with at least the same metering accuracy as can be achieved using gravimetric metering.

In view of the above, there is a need to provide an improved solid colorant dispensing device that can be used in a tinting machine for tinting base coating compositions and which obviates or at least reduces one or more of the above-mentioned disadvantages associated with solid colorant dispensing devices known in the art.

Disclosure of Invention

It is an object of the present invention to provide a solid colorant dispensing device configured to dispense at least one dose of solid spherical colorant particles in a time-controlled manner. The solid colorant dispensing device according to the present invention preempts or at least reduces at least one of the above and/or other disadvantages associated with solid colorant dispensing devices known in the art by enabling solid spherical colorant particles to be dispensed in a less delicate but more efficient manner while achieving at least the same metering accuracy as compared to solid colorant dispensing devices known in the art.

Another object of the present invention is to provide a tinting machine configured to tint a base coating composition with at least one dose of solid spherical colorant particles dispensed in a time-controlled manner by at least one solid colorant dispensing device according to the present invention. The tinting machine according to the invention, in which the solid colorant dispensing device according to the invention is applied, enables improved control of the tinting of the base coating composition. The resulting pigmented base coating composition has at least the same properties, but generally improved properties, compared to the properties of pigmented base coating compositions obtained using gravimetric metering of solid colorant particles.

Aspects of the invention are set out in the accompanying independent and dependent claims. Features from the independent and dependent claims may be combined as appropriate and not merely as explicitly set out in the claims. Furthermore, all the features may be replaced by other technically equivalent features.

At least one of the above objects is achieved by a solid colorant dispensing device configured to dispense at least one dose of solid spherical colorant particles in a time-controlled manner, the solid colorant dispensing device comprising:

-a supply container comprising a free end portion provided with a nozzle configured and arranged to dispense said at least one dose of solid spherical colorant particles during operation of said solid colorant dispensing device, said solid spherical colorant particles having the following characteristics:

-a number average particle size; and

-a number particle size distribution, wherein the ratio of the standard deviation of the number particle size distribution to the number average particle size of the solid colorant particles is less than 25%, preferably less than 22%, more preferably less than 20%, wherein the particle size analysis-image analysis method-first part according to ISO13322-1: 2004: a static image analysis method, using an Onchio particle size particle shape analyzer to determine the number particle size distribution by light scattering and full-automatic image analysis;

the nozzle comprises a dispensing outlet having a diameter that takes into account the number average particle size of the solid spherical colorant particles; and

-a control assembly configured and arranged to control the dispensing of the at least one dose of solid spherical colorant particles in a time-controlled manner by taking into account the characteristics of the solid spherical colorant particles and the diameter of the dispensing outlet of the nozzle.

It will be appreciated by those skilled in the art that the above-described time-controlled metering of at least one dose of solid spherical colorant particles enables volumetric metering of the solid spherical colorant particles rather than gravimetric metering thereof. Volumetric metering of solid spherical colorant particles is faster than gravimetric metering because volumetric metering, as opposed to gravimetric metering, does not require mid-scale (scale) measurements of the solid spherical colorant particles to be metered. Furthermore, volumetric metering requires less hardware because no scales and any additional containers associated with any intermediate scale measurements are required. Furthermore, volumetric metering enables at least two doses of different solid spherical colorant particles to be metered simultaneously. In this way, the metering time can be reduced even further.

Furthermore, it will be appreciated by the skilled person that the properties of the solid spherical colorant particles, in particular the fact that the ratio of the standard deviation of the number particle size distribution of the solid spherical colorant particles to the number average particle size is less than 25%, preferably less than 22%, more preferably less than 20%, enable accurate volumetric metering thereof. Due to the well-defined shape and narrow number particle size distribution of the solid spherical colorant particles (also known as pearlescence), the solid spherical colorant particles can be dispensed at a predictable and well-controlled flow rate. Furthermore, the narrow number particle size distribution of the solid spherical colorant particles allows the tap density and the bulk density of the solid spherical colorant particles to have respective values as close as possible. Furthermore, due to their well-defined characteristics, in particular shape and narrow number particle size distribution, the control assembly can control the dispensing of at least one dose of solid spherical colorant particles in a time-controlled manner by taking into account the properties of said particles and the diameter of the dispensing outlet of the nozzle of the supply container. From the above it is clear that solid colorant particles having at least one of an irregular shape and a broad, even bimodal number particle size distribution are not suitable for use with the solid colorant dispensing device according to the present invention.

It should be noted that one skilled in the art will appreciate that the particle size and particle size distribution of the solid colorant particles may be determined using any particle size and shape analyzer, such as the ochio size particle shape (occio ZEPHYR ESR) analyzer, which operates according to ISO13322-1:2004, particle size analysis-image analysis method-first part: a static image analysis method.

In the context of the present invention, an OCCHIO ZEPHYR ESR analyzer has been used, which performs precise size and shape analysis of free-flowing powders with particle sizes ranging from 20 μm to 30 μm. Each solid colorant particle sample was provided to a vibratory feeder where it was transported to a vertical shaft (drop craft) to obtain the gravity dispersion of the sample in an occio ZEPHYR ESR analyzer. Thereafter, a picture of all particles in focus is taken using the camera. For each sample, a particle size of 50000 particles was analyzed. Statistical evaluation was performed using the CALLISTO software.

It is to be noted that a colorant is to be interpreted as any substance (e.g. dye, pigment, ink or paint) that can affect the color or can change the hue of something else. A solid colorant is a solid composition that can be added to a point-of-sale coating container that has an internal volume that is already large (e.g., two-thirds or more of the container volume) but is not filled with a base coating composition in order to change the hue or brightness of such base coating compositions, as well as compositions containing pigments. An advantage of dispensing colourant in the form of solid spherical particles is that the environment of the dispenser unit becomes less dirty than colourants supplied in particular in powder form. Furthermore, the use of solid spherical colorant particles reduces the chance of inhalation by the operator of the dispensing device according to the invention.

Based on the foregoing, it will be appreciated by those skilled in the art that the solid colorant dispensing device according to the present invention is capable of volumetric metering of at least one dose of solid spherical colorant particles in a less elaborate but more efficient manner than using gravimetric metering, while achieving at least the same metering accuracy.

In an embodiment of the solid colorant dispensing apparatus according to the invention, the control assembly comprises a solenoid comprising a spring-loaded plunger, wherein when the solenoid is in an inactive state, the spring-loaded plunger is configured and arranged with respect to the dispensing outlet of the nozzle to prevent the nozzle from dispensing solid spherical colorant particles, and when the solenoid is in an active state, the spring-loaded plunger is configured and arranged with respect to the dispensing outlet of the nozzle to allow the nozzle to dispense solid spherical colorant particles. By using a solenoid and a spring-loaded plunger, even very small doses of solid spherical colorant particles can be accurately dispensed in a time-controlled manner. In this way, the solid colorant dispensing device according to the invention has at least the same metering capability as that achievable with prior art solid colorant dispensing devices. However, the solid colorant dispensing device according to the present invention allows volumetric metering, which has the above-mentioned advantages over commonly used gravimetric metering techniques.

In an embodiment of the solid colorant dispensing device according to the invention, the spring-loaded plunger of the solenoid is arranged such that a longitudinal centre line of the spring-loaded plunger is oriented transversely to a longitudinal centre line of the nozzle. It will be appreciated by those skilled in the art that in this way the spring loaded plunger enables very rapid and accurate control of the opening and closing of the dispensing outlet of the nozzle and thus the dose of solid spherical colorant particles dispensed.

In an embodiment of the solid colorant dispensing device according to the invention, the spring-loaded plunger has a free end portion which is arrangeable in relation to the dispensing outlet of the nozzle for controlling the dispensing of the solid spherical colorant particles, wherein the free end portion has an outer circumference which is shaped such that: when the free end portion partially obstructs the dispensing outlet, a uniform flow of the solid spherical colorant particles dispensed is ensured. It will be appreciated by those skilled in the art that when the flow of the dispensed solid spherical colorant particles is disturbed by the free end of the spring loaded plunger, this will adversely affect the metering accuracy. If the outer periphery has a shape that provides a sharp edge behind which solid spherical colorant particles can catch, the flow of the dispensed solid spherical colorant particles can be disturbed. By providing the free end of the spring-loaded plunger with an outer periphery shaped to prevent solid spherical colorant particles from hanging behind the rim of the outer periphery as they flow out of the dispensing outlet of the nozzle as long as the dispensing outlet of the nozzle is partially obstructed by the free end, a uniform flow of dispensed particles can be ensured. Therefore, high dispensing accuracy can be achieved.

In an embodiment of the solid colorant dispensing device according to the invention, a detection unit is provided which is configured and arranged to determine a current inventory of solid spherical colorant particles in the supply vessel and to provide a detection signal corresponding to the determined current inventory to the control assembly. In this way, it is possible to detect in time when the inventory of solid spherical colorant particles in the container needs to be replenished. Thus, it can be avoided that the amount of solid spherical colorant particles in the supply container becomes so low that linear metering accuracy is no longer applicable. In addition, unnecessary down time due to lack of solid spherical colorant particles can be avoided.

In an embodiment of the solid colorant dispensing device according to the invention, the supply container comprises a first part having the free end portion provided with the nozzle and a second part having an end which is in open communication with an end of the first part arranged opposite the nozzle, thereby providing a transition between the second part and the first part, the first part having a conical inner wall arranged at an angle in the range of 15-55 degrees, preferably equal to 30 degrees, with respect to a longitudinal centre line of the first part. Due to the conical inner wall, all solid spherical colorant particles are directed towards the dispensing outlet of the nozzle. It will be appreciated by those skilled in the art that the nozzle dispenses solid spherical colorant particles at a flow rate that is dependent on the height, and therefore the amount, of the solid spherical colorant particles of the inventory of solid spherical colorant particles present above the transition between the second portion and the first portion of the supply vessel. Furthermore, the flow rate depends on the number average particle diameter of the solid spherical colorant particles, the diameter of the dispensing outlet of the nozzle and the angle of the conical inner wall of the first portion of the supply vessel.

In an embodiment of the solid colorant dispensing device according to the invention, the control assembly is configured to set a dispensing time interval, during the dispensing time interval, the solenoid switches from the inactive state to the active state and back to the inactive state, to allow the nozzle to dispense a dose of solid spherical colorant particles taking into account at least the diameter of the dispensing outlet of the nozzle, the angle of the tapered inner wall of the first portion of the supply vessel, the current inventory of solid spherical colorant particles in the supply vessel, and a response time of the solenoid, wherein a response time of the solenoid is dependent on a switching signal received from the control assembly to switch between the inactive state and the active state.

In an embodiment of the solid colorant dispensing device according to the invention, an overflow compartment is provided, which is configured and arranged with respect to the dispensing outlet of the nozzle to receive solid spherical colorant particles dispensed by the nozzle as a result of displacing the spring-loaded plunger in response to switching the solenoid from the active state to the inactive state. It will be appreciated by the person skilled in the art that the amount of solid spherical colorant particles received in the overflow compartment may also be considered in relation to the desired amount of solid spherical colorant particles to be dispensed. In this way, the loss of solid spherical colorant particles can be minimized. Furthermore, it will be appreciated by those skilled in the art that the overflow compartment prevents the dispensing outlet of the nozzle from clogging. Furthermore, in order to achieve accurate metering, the amount of solid spherical colorant particles that eventually enter the overflow compartment needs to be taken into account when setting the dispensing time interval.

In an embodiment of the solid colorant dispensing device according to the invention, a vibration unit is provided which is configured and arranged to allow the supply container to vibrate at a frequency in the range of 0-55Hz during operation of the solid colorant dispensing device. The vibration unit may be any device, such as a vibration motor that allows at least the first portion of the supply container to vibrate during operation of the solid colorant dispensing device. It will be appreciated by those skilled in the art that the dispensing of solid spherical colorant particles may be interrupted due to bridging of the solid spherical colorant particles near the dispensing outlet of the nozzle. By vibrating at least the first part of the supply container, bridging of solid spherical colorant particles can be prevented. Furthermore, by vibrating at least the first portion of the supply container, an improved build-up of solid spherical colorant particles in the supply container may be obtained, since residual air between the particles may be removed.

In an embodiment of the solid colorant dispensing apparatus according to the invention, a replaceable cartridge containing solid spherical colorant particles is provided, the replaceable cartridge being associated with the supply container so as to provide an inventory of solid spherical colorant particles to the supply container and to allow the inventory in the supply container to be automatically replenished with solid spherical colorant particles from the replaceable cartridge until the replaceable cartridge is empty in response to dispensing at least one dose of solid spherical colorant particles via the nozzle.

The replaceable cartridge is used to initially fill the supply container at least to a level above a predetermined height above a transition between the second portion and the first portion of the supply container. Typically, the supply container is filled with solid spherical colorant particles from a replaceable cartridge. In case the capacity of the exchangeable cartridge is equal to the capacity of the supply container, the exchangeable cartridge will be empty after the initial filling of the supply container and needs to be exchanged for another exchangeable cartridge. In the case where the volume of the replaceable cartridge is greater than the volume of the supply container, solid spherical colorant particles remaining in the replaceable cartridge after the initial filling of the supply container are inserted into the supply container until the replaceable cartridge is empty, and a dose of the solid spherical colorant particles is dispensed each time by the nozzle. In the case where the volume of the replaceable cartridge is less than the volume of the supply container, it is important that the current inventory of solid spherical colorant particles in the supply container can be replenished at least to a level above a predetermined height above the transition between the second portion and the first portion of the supply container.

One skilled in the art will appreciate that the nozzle may dispense solid spherical colorant particles at a substantially constant flow rate until the inventory of solid spherical colorant particles reaches a predetermined height above the transition between the second portion and the first portion of the supply vessel. The flow rate begins to decrease when the inventory of solid spherical colorant particles falls below a predetermined height above the transition between the second portion and the first portion of the supply vessel. In that case, the detection unit provides a signal to the control assembly indicating that the current inventory of solid spherical colorant particles needs to be replenished and that an empty replaceable cartridge needs to be replaced.

In an embodiment of the solid colorant dispensing device according to the invention, the number average particle diameter of the solid spherical colorant particles is in the range of 400 μm to 1400 μm, preferably in the range of 500 μm to 1300 μm, more preferably in the range of 600 μm to 1000 μm.

In an embodiment of the solid colorant dispensing device according to the invention, the solid spherical colorant particles comprise 30 wt% to 97 wt% pigment, less than 5 wt% solvent and 3 wt% to 40 wt% surfactant, wherein wt% is related to the total weight of the solid spherical colorant particles.

In an embodiment of the solid colorant dispensing device according to the invention, the dispensing outlet of the nozzle has a diameter in the range of 5mm-15 mm.

It will be appreciated by those skilled in the art that the diameter of the dispensing outlet of the nozzle will be selected taking into account the number average particle size of the solid spherical colorant particles. For solid spherical colorant particles having a number average particle size in the range of 400 μm to 1400 μm, a dispensing outlet having a diameter of less than 5mm will be easily clogged. However, for solid spherical colorant particles having a number average particle size within the above range, if the dispensing outlet is greater than 15mm in diameter, the switching of the solenoid between the inactive and active states will be critical, since the switching speed will not be fast enough to prevent dispensing of too many solid spherical colorant particles. For solid spherical colorant particles having a number average particle size in the range of 400 μm to 1400 μm, the dispensing outlet of the nozzle preferably has a diameter of 8 mm.

In an embodiment of the solid colorant dispensing device according to the invention, the spring-loaded plunger has a stroke in the range of 5mm to 16 mm. In this way, when the solenoid is in the inactive state, the free end of the spring-loaded plunger is positioned relative to the dispensing outlet of the nozzle to prevent dispensing of solid spherical colorant particles by blocking the dispensing outlet in use of the dispensing device. Blocking the dispensing outlet. As mentioned above, for solid spherical colorant particles having a number average particle size in the range of 400 μm to 1400 μm, the dispensing outlet of the nozzle preferably has a diameter of 8 mm. In that case, the free end of the plunger preferably has a stroke of 8.2 mm.

According to another aspect of the present invention, there is provided a tinting machine configured to tint a base coating composition with at least one dose of solid spherical colorant particles dispensed in a time-controlled manner by a solid colorant dispensing apparatus according to the present invention. The color mixer includes:

-a receiving space configured and arranged to receive a paint container containing the base paint composition to be pigmented with the at least one dose of solid spherical colorant particles;

-a guide configured and arranged to guide the at least one dose of solid spherical colorant particles dispensed by the at least one solid colorant dispensing device into the coating container;

-a main control assembly configured and arranged to communicate with the control assembly of the at least one solid colorant dispensing device to control the dispensing of the at least one dose of solid spherical colorant particles by the at least one solid colorant dispensing device.

It will be appreciated by the skilled person that the tinting machine according to the invention is capable of dispensing at least one dose of solid spherical colourant particles directly into a paint container containing a base paint composition which requires tinting, since no balance is required in the volumetric metering. In this way, the balance is no longer a limiting factor with respect to the size and/or weight of the paint container.

An exemplary embodiment of a tinting machine according to the invention comprises a plurality of solid colorant dispensing devices according to the invention, wherein the plurality comprises at least two solid colorant dispensing devices. To limit the footprint of the tinting machine, those skilled in the art will appreciate that a matrix arrangement is preferred for the plurality of solid colorant dispensing devices. A main control assembly of the tinting machine is configured and arranged to communicate individually with each control assembly of a different solid colorant dispensing device of the plurality of dispensing devices. Thus, the main control assembly is capable of controlling the solid colorant dispensing devices of the plurality of dispensing devices to simultaneously or sequentially dispense doses of solid spherical colorant particles. It will be appreciated by those skilled in the art that the use of a tinting machine according to the invention to tint base coating compositions can be much faster than the use of a gravimetric tinting machine.

Drawings

Further characteristics and advantages of the invention will become apparent from the description of the invention in the form of an exemplary and non-limiting embodiment of a solid colorant dispensing device and of a tinting machine comprising such a dispensing device.

Those skilled in the art will appreciate that the described embodiments of the solid colorant dispensing device and the tinting machine are merely exemplary in nature and should not be construed as limiting the scope of protection in any way. It will be appreciated by those skilled in the art that alternative and equivalent embodiments of the solid colorant dispensing device and the tinting machine are contemplated and may be made without departing from the scope of the invention.

Reference will now be made to the drawings in the drawings. The figures are schematic in nature and, thus, are not necessarily drawn to scale. Further, the same reference numerals denote the same or similar parts. On the basis of the attached drawings, it is shown,

FIG. 1 shows a schematic perspective view of an exemplary, non-limiting embodiment of a solid colorant dispensing apparatus according to the present invention;

FIG. 2 shows an enlarged view of the spring loaded plunger, the dispensing outlet of the nozzle and the overflow compartment of the solid colorant dispensing device shown in FIG. 1;

FIG. 3 shows a schematic bottom view of the solid colorant dispensing apparatus shown in FIG. 1 when the solenoid is in an inactive state and the spring-loaded plunger is disposed about the dispensing outlet of the nozzle of the supply container to prevent dispensing of solid spherical colorant particles;

FIG. 4 shows a schematic bottom view of the solid colorant dispensing device shown in FIG. 1 when the solenoid is in an active state and the spring-loaded plunger is disposed about the dispensing outlet of the nozzle of the supply container to allow dispensing of a dose of solid spherical colorant particles;

FIG. 5A shows a schematic side view of a solid colorant dispensing apparatus having an empty supply container with a first replaceable cartridge placed on top of the supply container to fill the supply container with solid spherical colorant particles according to the embodiment shown in FIG. 1;

FIG. 5B schematically illustrates the solid colorant dispensing device shown in FIG. 5A with the supply container filled with solid spherical colorant particles and the first replaceable cartridge empty;

FIG. 5C schematically illustrates the situation where the supply container of the solid colorant dispensing apparatus shown in FIG. 5B is filled with solid spherical colorant particles from a first replaceable cartridge and the first replaceable cartridge has been replaced with a second replaceable cartridge filled with solid spherical colorant particles;

FIG. 5D schematically illustrates the situation where the supply container of the solid colorant dispensing device shown in FIG. 5C is filled with solid spherical colorant particles and the second replaceable cartridge contains the remaining solid spherical colorant particles 2;

FIG. 5E schematically illustrates a situation in which the second replaceable cartridge is empty and the supply container of the solid colorant dispensing device is still filled;

FIG. 5F schematically illustrates a situation in which the second replaceable cartridge is completely empty and the current inventory of solid spherical colorant particles in the supply vessel is at a predetermined height above the transition between the first portion and the second portion of the supply vessel of the solid colorant dispensing device; and

fig. 6 shows a schematic perspective view of an exemplary, non-limiting embodiment of a tinting machine according to the invention.

Detailed Description

Fig. 1 shows a schematic perspective view of an exemplary, non-limiting embodiment of a solid colorant dispensing device 1 according to the present invention, which is configured to dispense at least one dose of solid spherical colorant particles 2 in a time-controlled manner. The solid colorant dispensing device 1 comprises a supply container 3, the supply container 3 having a free end portion 4, the free end portion 4 being provided with a nozzle 5, the nozzle 5 being constructed and arranged to dispense the at least one dose of solid spherical colorant particles 2 during operation of the solid colorant dispensing device 1. The solid spherical colorant particles 2 have a number average particle diameter and a number particle diameter distribution that enable volume metering of the solid spherical colorant particles 2. The ratio of the standard deviation of the number particle size distribution of the solid spherical colorant particles 2 to the number average particle size is less than 25%, preferably less than 22%, more preferably less than 20%. It will be appreciated by those skilled in the art that due to the well-defined shape and narrow number particle size distribution of the solid spherical colorant particles 2 (also known as pearlescence), the solid spherical colorant particles 2 can be dispensed at a predictable and controllable flow rate. Particle size analysis-image analysis method-first part according to ISO13322-1: 2004: number particle size distribution was determined by light scattering and fully automated image analysis using a static image analysis method of an ohyo particle size particle shape (occio ZEPHYR ESR) analyzer.

The number average particle diameter of the solid spherical colorant particles 2 is in the range of 400 μm to 1400 μm, preferably in the range of 500 μm to 1300 μm, and more preferably in the range of 600 μm to 1000 μm. The solid spherical colorant particles 2 comprise from 30 wt% to 97 wt% of a pigment, less than 5 wt% of a solvent, and from 3 wt% to 40 wt% of a surfactant, wherein the wt% is related to the total weight of the solid spherical colorant particles 2.

The nozzle 5 of the supply container 3 of the solid colorant dispensing device 1 shown in fig. 1 further comprises a dispensing outlet 6, the dispensing outlet 6 being shown in more detail in fig. 2, 3A and 3B. The dispensing outlet 6 has a diameter 7, taking into account the number average particle diameter of the solid spherical colorant particles 2. Fig. 2 also shows an enlarged view of the overflow compartment 26 of the solid colorant dispensing device 1 shown in fig. 1.

The solid colorant dispensing apparatus 1 shown in fig. 1 further comprises a control assembly 8, the control assembly 8 being configured and arranged to: the dispensing of the at least one dose of solid spherical colorant particles 2 is controlled in a time-controlled manner by taking into account the well-defined characteristics of the solid spherical colorant particles 2, in particular the shape and the number particle size distribution, and the diameter 7 of the dispensing outlet 6 of the nozzle 5.

The control assembly 8 of the solid colorant dispensing device 1 according to the exemplary, non-limiting embodiment shown in fig. 1 comprises a solenoid 9, the solenoid 9 comprising a spring-loaded plunger 10. When the solenoid 9 is in an inactive state, i.e. when no electrical bias is provided to the solenoid, a spring-loaded plunger 10 is arranged with respect to the dispensing outlet 6 of the nozzle 5 to prevent the nozzle 5 from dispensing solid spherical colorant particles 2. This is shown in more detail in fig. 3. However, when the solenoid 9 is in an active state, i.e. when an electrical bias is provided to the solenoid, the spring-loaded plunger 10 is arranged with respect to the dispensing outlet 6 of the nozzle 5 to allow the nozzle 5 to dispense the solid spherical colorant particles 2. This is shown in more detail in fig. 4.

It will be appreciated by those skilled in the art that by using a solenoid 9 comprising a spring loaded plunger 10, even very small doses of solid spherical colorant particles can be accurately dispensed in a time controlled manner. In this way, the solid colorant dispensing device 1 according to the invention has a dispensing capacity that is at least as great as that achievable with prior art solid colorant dispensing devices. However, the solid colorant dispensing device 1 according to the invention allows volumetric metering, which has the above-mentioned advantages over the commonly used gravimetric metering techniques.

According to the exemplary, non-limiting embodiment of the solid colorant dispensing device 1 shown in fig. 1, the spring-loaded plunger 10 of the solenoid 9 is arranged such that its longitudinal centerline 11 is oriented transversely to the longitudinal centerline 12 of the nozzle 5. It will be appreciated by those skilled in the art that in this way the spring loaded plunger 10 enables very rapid and accurate control of the opening and closing of the dispensing outlet 6 of the nozzle 5 and hence the dose of solid spherical colorant particles 2 dispensed.

The exemplary, non-limiting embodiment of the solid colorant dispensing device 1 shown in fig. 1 includes a vibration unit 27, such as a vibration motor or any other suitable device, the vibration unit 27 being configured and arranged to allow the supply vessel 3 to vibrate at a frequency in the range of 0-55Hz during operation of the solid colorant dispensing device 1. It will be appreciated by those skilled in the art that by vibrating the supply container, so-called bridging of the solid spherical colorant particles 2 located near the dispensing outlet 6 of the nozzle 5, which would interrupt the dispensing of the solid spherical colorant particles 2, may be prevented. Furthermore, by vibrating the supply container 3, an improved packing of the solid spherical colorant particles 2 in the supply container 3 can be obtained, since residual air between the particles can be removed.

The exemplary, non-limiting embodiment of the solid colorant dispensing device 1 shown in fig. 1 further comprises a detection unit 16, the detection unit 16 being configured and arranged to determine a current inventory 17 of solid spherical colorant particles 2 in the supply vessel 3 and to provide a detection signal corresponding to the determined current inventory 17 to the control assembly 8. Those skilled in the art will appreciate that the detection unit 16 may be operatively connected to the control assembly 8 using, for example, at least one of an electrical connection and an optical connection. The connection may be established in at least one of a wired and wireless manner. The detection unit 16 enables timely detection of when the stock 17 of solid spherical colorant particles 2 in the container 3 needs to be replenished. Thus, unnecessary downtime due to the lack of solid spherical colorant particles 2 can be avoided.

In the exemplary, non-limiting embodiment of the solid colorant dispensing device 1 shown in fig. 1, the supply container 3 comprises a first portion 18 having a free end portion 4 and a second portion 20 having an end portion 21, the free end portion 4 being provided with the nozzle 5, the end portion 21 of the second portion 20 being connected in open communication to an end portion 22 of the first portion 18 arranged opposite the nozzle 5, so as to provide a transition 19 between the second portion 20 and the first portion 18. The first portion 18 has a tapered inner wall 23, which tapered inner wall 23 is arranged at an angle a in the range of 15-55 degrees, preferably equal to 30 degrees, with respect to its longitudinal centre line 24. Because of the conical inner wall 23, all solid spherical colorant particles 2 are directed towards the dispensing outlet 6 of the nozzle 5. It will be appreciated by those skilled in the art that the nozzle 5 dispenses the solid spherical colorant particles 2 at a flow rate that is dependent on the height, and therefore the amount, of the solid spherical colorant particles 2 of the current inventory 17 of solid spherical colorant particles 2 present above the transition 19 between the second portion 20 and the first portion 18 of the supply vessel 3. In addition, the flow rate depends on the number average particle diameter of the solid spherical colorant particles 2, the diameter 7 of the dispensing outlet 6 of the nozzle 5 and the angle α of the conical inner wall 23 of the first portion 18 of the supply container 3. The total height of the supply container 3 is typically in the range 40mm-600mm, preferably 223 mm.

It is noted that the control assembly 8 is configured to set a dispensing time interval during which the solenoid 9 is switched from the inactive state to the active state and back to the inactive state to allow the nozzle 5 to dispense a dose of solid spherical colorant particles 2 taking into account at least the diameter 7 of the dispensing outlet 6 of the nozzle 5, the angle α of the tapered inner wall 23 of the first portion 18 of the supply vessel 3, the current inventory 17 of solid spherical colorant particles 2 in the supply vessel 3, and the response time of the solenoid 9, wherein the response time of the solenoid 9 is dependent on receiving a switching signal from said control assembly 8 to switch between said inactive state and said active state. Typical dispensing time intervals for the solid colorant dispensing device 1 according to the invention are in the range of 5ms to 100 ms.

It will be appreciated by those skilled in the art that the solenoid 9 switches from the inactive state to the active state by applying an electrical bias to the solenoid 9 during a set dispensing time interval. In the active state, the spring-loaded plunger 10 is retracted. Thus, the nozzle 5 can dispense solid spherical colorant particles 2, since the dispensing outlet 6 of the nozzle is at most partially blocked by the spring-loaded plunger 10. It will be appreciated by those skilled in the art that it is preferred that the dispensing outlet 6 of the nozzle 5 is completely unobstructed by the spring loaded plunger 10 when the solenoid 9 is active. At the end of the dispensing time interval, the solenoid 9 switches from the active state back to the inactive state. As a result, the spring-loaded plunger 10 is displaced by the spring associated with the plunger, thereby blocking the dispensing outlet 6 of the nozzle 5 to prevent the nozzle 5 from dispensing solid spherical colorant particles 2.

Fig. 2 shows an enlarged view of the spring-loaded plunger 10, the dispensing outlet 6 of the nozzle and the overflow compartment 26 of the solid colorant dispensing device 1 shown in fig. 1. Fig. 2 provides a better view of the arrangement of these components with respect to each other. The overflow compartment 26 is constructed and arranged with respect to the dispensing outlet 6 of the nozzle to receive solid spherical colorant particles 2 dispensed by the nozzle as a result of displacement of the spring-loaded plunger 10 to block the dispensing outlet 6 of the nozzle in response to switching the solenoid from the active state to the inactive state. It will be appreciated by the person skilled in the art that the amount of solid spherical colorant particles 2 received in the overflow compartment 26 may also be considered in relation to the desired amount of solid spherical colorant particles 2 to be dispensed. The solid spherical colourant granules 2 received in the overflow compartment 26 are also directed into a paint container containing the base paint composition to be coloured. In this way, unnecessary loss of solid spherical colorant particles 2 can be minimized.

It will be appreciated by those skilled in the art that the diameter 7 of the dispensing outlet 6 of the nozzle will be selected taking into account the number average particle size of the solid spherical colorant particles 2. For solid spherical colorant particles 2 having a number average particle size in the range of 400 μm to 1400 μm, a dispensing outlet 6 having a diameter 7 of less than 5mm will become too susceptible to clogging. However, for solid spherical colorant particles 2 having a number average particle size within the above range, if the diameter 7 of the dispensing outlet 6 is greater than 15mm, switching of the solenoid 9 between the inactive state and the active state will be very difficult, since the switching speed will not be fast enough to prevent dispensing of too many solid spherical colorant particles 2. For solid spherical colorant granules 2 having a number average particle diameter in the range of 400 μm to 1400 μm, the diameter 7 of the dispensing outlet 6 of the nozzle is in the range of 5mm to 15mm, preferably 8 mm.

Fig. 2 shows that the spring-loaded plunger 10 is provided with an elongated recess. Thus, mechanical friction may be reduced and a faster displacement of the spring loaded plunger 10 may be achieved. Thus, an allocation interval around the lower boundary of the above-mentioned 5ms-100ms range can be achieved.

Although not shown, the side of the spring-loaded plunger that is arranged to face the dispensing outlet of the nozzle preferably has a flat surface. In this way, a constant and uniform outflow of solid spherical colorant particles from the nozzle can be achieved when the solenoid moves the spring-loaded plunger.

Fig. 3 shows a schematic bottom view of the solid colorant dispensing device 1 shown in fig. 1 when the solenoid 9 is in an inactive state and the spring-loaded plunger 10 is arranged with respect to the dispensing outlet 6 of the nozzle of the supply container 3 to prevent dispensing of the solid spherical colorant particles 2.

Fig. 4 shows a schematic bottom view of the solid colorant dispensing device 1 shown in fig. 1 when the solenoid 9 is active and the spring-loaded plunger 10 is arranged with respect to the dispensing outlet 6 of the nozzle of the supply container 3 to allow dispensing of a dose of solid spherical colorant particles 2.

As can be seen from fig. 2, 3 and 4, the spring-loaded plunger 10 has a free end 13, which free end 13 can be arranged in relation to the dispensing outlet 6 of the nozzle 5 to control the dispensing of the solid spherical colorant particles 2, as described above. Fig. 2, 3 and 4 show an exemplary embodiment of the free end 13 of the spring-loaded plunger 10. According to this embodiment, the free end 13 has an outer periphery 14, the shape of the outer periphery 14 being configured to ensure a uniform flow of the dispensed solid spherical colorant particles 2 when the free end 13 partially obstructs the dispensing outlet 6. It will be appreciated by those skilled in the art that when the flow of the solid spherical colorant granules 2 being dispensed is disturbed by the free end 13 of the spring loaded plunger 10, this will adversely affect the metering accuracy. If the outer periphery 14 has a shape that provides a sharp edge behind which the solid spherical colorant particles 2 can catch, the flow of the dispensed solid spherical colorant particles can be disturbed. By the free end 13 of the spring-loaded plunger 10 being provided with an outer periphery whose shape prevents solid spherical colorant particles from hanging behind the edge of the outer periphery of the nozzle as they flow out of the dispensing outlet 6 thereof as long as the dispensing outlet 6 is partially blocked by the free end 13, a uniform flow of dispensed particles can be ensured. Therefore, high dispensing accuracy can be achieved.

According to an embodiment of the free end 13 of the plunger 10 as a spring, the outer circumference of the free end 13 has a semi-circular shape. It will be appreciated by those skilled in the art that the outer periphery 14 of the free end 13 of the spring loaded plunger 10 may have any polygonal shape that enables uniform flow of the solid spherical colorant particles 2 being dispensed.

A comparison of the position of the free end of the spring loaded plunger 10 as shown in figures 3 and 4 respectively shows that the spring loaded plunger 10 has a stroke 15. According to the embodiment of the solid colorant dispensing device shown in fig. 1-4, the stroke 15 of the spring-loaded plunger 10 is typically in the range of 5mm-16 mm. The stroke 15 of the spring loaded plunger 10 must be such that, when the solenoid 9 is in an inactive state, the free end 13 of the spring loaded plunger 10 is positioned relative to the dispensing outlet 6 of the nozzle to prevent dispensing of the solid spherical colorant particles 2 by blocking the dispensing outlet 6. However, when the solenoid 9 is active, the stroke must be sufficient to displace the free end 13 of the spring-loaded plunger 10 with respect to the dispensing outlet 6 of the nozzle to allow a uniform flow of solid spherical colorant particles 2 to be dispensed by the nozzle. As mentioned above, for solid spherical colorant granules 2 having a number average particle diameter in the range of 400 μm to 1400 μm, the dispensing outlet 6 of the nozzle preferably has a diameter 7 of 8 mm. In that case, the free end 13 of the spring-loaded plunger 10 preferably has a stroke of 8.2 mm.

Fig. 5A shows a schematic side view of a solid colorant dispensing device 1 according to the embodiment shown in fig. 1, the solid colorant dispensing device 1 having an empty supply container 3, a first replaceable cartridge 28 being placed on top of the empty supply container 3 to fill the supply container 3 with solid spherical colorant particles 2. It will be appreciated by those skilled in the art that the first replaceable cartridge 28 may be used to initially fill the supply container 3 to a level above the predetermined height 35 above the transition 19 between the first portion 18 and the second portion 20 of the supply container 3. The supply container 3 is typically filled with solid spherical colorant particles 2 from the first replaceable cartridge 28, after which the first replaceable cartridge 28 is emptied, as shown in fig. 5B. Fig. 5C schematically shows a case where the supply container 3 of the solid colorant dispensing device 1 shown in fig. 5B is filled with solid spherical colorant particles from the first replaceable cartridge 28, and the first replaceable cartridge 28 has been replaced with the second replaceable cartridge 39 filled with the solid spherical colorant particles. The second replaceable cartridge 39 is configured to allow the inventory of solid spherical colorant particles 2 in the supply container 3 to be automatically replenished with solid spherical colorant particles 2 from the second replaceable cartridge 39 until the second replaceable cartridge 39 is empty, each time a dose of solid spherical colorant particles 2 is dispensed by the dispensing outlet 6 of the nozzle. Fig. 5D schematically illustrates a case where the supply container 3 of the solid colorant dispensing device 1 illustrated in fig. 5C is filled with solid spherical colorant particles 2 and the second replaceable cartridge 39 includes the remaining solid spherical colorant particles 2.

Fig. 5E schematically illustrates a situation in which the second replaceable cartridge 39 is empty and the supply container 3 of the solid colorant dispensing device 1 is still filled. Those skilled in the art will appreciate that the solid spherical colorant particles 2 may be dispensed at a flow rate that decreases in a substantially linear manner as the height of the inventory of solid spherical colorant particles 2 decreases until the inventory of solid spherical colorant particles reaches the transition 19 between the first portion 18 and the second portion 20 of the supply vessel 3. For a supply container 3 comprising solid spherical colorant particles 2 having a number average particle diameter in the range of 400 μm to 1400 μm and a height reaching a predetermined height 35 (see fig. 5F) above a transition 19 between the first portion 18 and the second portion 20 of the supply container 3, and having a nozzle with a dispensing outlet 6 having a diameter of 8mm and having a first portion 18 with its conical inner wall 23 at an angle α of 30 degrees with respect to its longitudinal centerline 24, the solid spherical colorant particles 2 can be dispensed at a flow rate in the range of 200 ml/min to 400 ml/min. Due to the well-defined nature of the solid spherical colorant particles 2, the solid spherical colorant particles 2 can be dispensed in a constant homogenous flow. This allows even small doses of solid spherical colorant particles 2 to be metered very precisely in volume.

Fig. 5F schematically illustrates a situation in which the second replaceable cartridge 39 is completely empty and the current inventory of solid spherical colorant particles 2 in the supply container 3 is at the above-mentioned predetermined height 35 above the transition 19 between the first portion 18 and the second portion 20 of the supply container 3 of the solid colorant dispensing device 1. It will be appreciated by those skilled in the art that the flow rate becomes very low if the inventory of solid spherical colorant particles 2 drops below a predetermined height 35 above the transition 19 between the first portion 18 and the second portion 20 of the supply vessel 3. The detection unit 16 should provide a signal to the control assembly 8 that the current inventory of solid spherical colorant particles 2 in the supply vessel 3 has reached a predetermined height 35 above the transition 19 between the first portion 18 and the second portion 20 of the supply vessel 3, and therefore needs replenishment. This may be accomplished by replacing the empty second replaceable cartridge 39 with a third replaceable cartridge (not shown) that is filled with solid spherical colorant particles 2 at least sufficient to replenish the current inventory of solid spherical colorant particles 2 in the supply vessel 3 above the predetermined height 35 above the transition 19 between the first portion 18 and the second portion 20 of the supply vessel 3. Typically, the third replaceable cartridge will be filled with solid spherical colorant particles of the desired kind.

Although not explicitly shown in the figures, it will be understood by those skilled in the art that alternative cartridges having a larger volume than the volume of the supply container of the solid colorant dispensing device according to the present invention may also be applied. In that case, the solid spherical colorant particles will remain in the first replaceable cartridge after the initial filling of the supply container with solid spherical colorant particles from the first replaceable cartridge. The first replaceable cartridge may be configured to allow the inventory of solid spherical colorant particles in the supply container to be automatically replenished with remaining solid spherical colorant particles from the first replaceable cartridge until the first replaceable cartridge is empty, each time a dose of solid spherical colorant particles is dispensed by the dispensing outlet of the nozzle. In fact, the situation described in relation to fig. 5D to 5F applies in a similar manner with regard to the replenishment of solid spherical colorant particles in the supply container, and the replacement of the first replaceable cartridge when the first replaceable cartridge is empty and the current inventory of solid spherical colorant particles in the supply container has reached a predetermined height above the transition between the first and second portions of the supply container.

Furthermore, it will be appreciated by those skilled in the art that in the case of the use of replaceable cartridges having a capacity less than the capacity of the supply container, it is important that the current inventory of solid spherical colorant particles in the supply container can be replenished at least to a level above a predetermined height above the transition between the second and first portions of the supply container.

Fig. 6 shows a schematic perspective view of an exemplary, non-limiting embodiment of a tinting machine 29 according to the invention. The tinting machine 29 is configured to tint the base coating composition 30 with at least one dose of solid spherical colorant particles 2, the at least one dose of solid spherical colorant particles 2 being dispensed in a time-controlled manner by at least one solid colorant dispensing device 1 according to the present invention. According to the exemplary embodiment shown in fig. 6, the tinting machine 29 comprises a matrix of sixteen solid colorant dispensing devices 1 according to the invention. It will be appreciated by those skilled in the art that any suitable number of solid colorant dispensing devices 1 may be used, depending on the specifications required for the tinting machine. In principle, all dispensing devices can be provided with replaceable cartridges 28, 39 comprising a specific kind of solid spherical colorant particles 2 having the above-mentioned well-defined characteristics. However, it is also possible to provide the replaceable cartridges 28, 39 only to a subset of the solid colorant dispensing devices 1 of the matrix of solid colorant dispensing devices 1, and not to the remaining solid colorant dispensing devices 1 that are not being employed. According to the exemplary, non-limiting embodiment of the tinting machine 29 shown in fig. 6, ten of the sixteen solid colorant dispensing devices 1 have been provided with replaceable cartridges 28, 39. It will be appreciated by those skilled in the art that the matrix arrangement of the solid colorant dispensing devices 1 is particularly advantageous for limiting the footprint of the tinting machine 29.

Furthermore, the tinting machine 29 shown in fig. 6 comprises a receiving space 31, which receiving space 31 is constructed and arranged to receive a paint container 32 containing said base paint composition 30, said base paint composition 30 being to be tinted with at least one dose of solid spherical colourant particles 2. Tinting machine 29 further comprises a guide 33, which guide 33 is configured and arranged to guide the at least one dose of solid spherical colorant particles 2 dispensed by the at least one solid colorant dispensing device 1 into the coating container 32.

The tinting machine 29 shown in figure 6 also comprises a main control assembly 34, the main control assembly 34 being configured and arranged to communicate with each of the ten solid colourant dispenser devices 1 employed. Thus, the main control assembly 34 may control the control assembly of each of ten solid colorant dispensing devices 1 in an exemplary matrix of sixteen dispensing devices 1 to simultaneously or sequentially dispense doses of solid spherical colorant particles 2. It will be appreciated in the art that the colouring of the base coating composition 30 using the tinting machine 29 according to the invention can be much faster than using a gravimetric-based tinting machine, since at least one dose of solid spherical colourant particles 2 can be dispensed directly into a coating container 32 containing the base coating composition 30 to be coloured.

Those skilled in the art will appreciate that the connection between the main control assembly 34 and any one of the ten solid colorant dispensing apparatuses 1 may be established by at least one of wired and wireless means.

Fig. 6 shows that an exemplary embodiment of tinting machine 29 is further provided with a vibration system 38, which vibration system 38 is configured and arranged to allow the guide 33 to vibrate to enhance the guidance of solid spherical colorant particles towards the paint container 32. The vibration system may vibrate guide 33 at a frequency in the range of 0-55 Hz.

Furthermore, it is worth noting that the guiding of the solid spherical colorant particles towards the paint container 32 may be further improved by providing an inner wall of the supply container and the guide of the solid colorant dispensing device which is in direct contact with at least one of the solid spherical colorant particles comprising aluminum or a polymer mixture suitable for injection molding. The inner wall is configured to be antistatic, abrasion resistant, hydrophobic and to have a surface roughness (Ra) of at most 0.3 μm.

The present invention may be summarized as relating to a solid colorant dispensing device 1 for dispensing doses of solid spherical colorant particles 2 in a time-controlled manner, comprising a supply container 3, which supply container 3 has a nozzle 5 for dispensing said particles having a number average particle diameter and a number particle diameter distribution, wherein the ratio of the standard deviation of the number particle diameter distribution of said particles to the number average particle diameter is less than 25%. The nozzle comprises a dispensing outlet 6 having a diameter 7, which diameter 7 takes into account the number average particle size of said particles. The dispensing device comprises a control assembly 8 for controlling the dispensing of the dose of the particles by taking into account the characteristics of the particles and the diameter of the nozzle outlet. The invention also relates to a tinting machine 29 comprising said solid colorant dispensing device.

It will be clear to a person skilled in the art that the scope of the present invention is not limited to the examples discussed in the foregoing, but that several amendments and modifications thereof are possible without deviating from the scope of the present invention as defined in the attached claims. In particular, combinations of particular features of the various aspects of the invention may be made. One aspect of the invention may be further advantageously enhanced by adding features described in relation to another aspect of the invention. While the invention has been illustrated and described in detail in the drawings and the description, such illustration and description are to be considered illustrative or exemplary only, and not restrictive.

The invention is not limited to the disclosed embodiments. Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other steps or elements, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims shall not be construed as limiting the scope of the invention.

Reference mark

1 solid colorant dispensing device

2 solid spherical colorant particles

3 supply container

4 free end portion of supply container

5 spray nozzle

6-nozzle dispensing outlet

7 diameter of the dispensing outlet

8 control assembly

9 solenoid

10 spring type plunger

11 longitudinal center line of spring type plunger

12 longitudinal center line of nozzle

Free end of 13 spring type plunger

Outer periphery of free end of 14-spring type plunger

15 spring type plunger stroke

16 detection unit

17 Current inventory of solid spherical colorant particles

18 first part of supply container

19 transition between the first and second parts of the supply container

20 second part of the supply container

21 free end of the second part of the supply container

22 end of the first part of the supply container arranged opposite to the nozzle

23 tapered inner wall of the first part of the supply container

24 longitudinal centerline of the first portion of the supply vessel

Angle of arrangement of conical inner wall of first part of alpha feed vessel with respect to its longitudinal centre line

26 overflow compartment

27 vibration unit

28 first replaceable cartridge

29 coloring machine

30 base coating composition

31 receiving space

32 paint container

33 guide piece

34 Main control assembly

35 is located at a predetermined height above the transition between the first and second parts of the supply container

Angle between beta guide bottom and centre line of paint container, centre line of paint container is transverse to longitudinal centre line of paint container

36 longitudinal centerline of paint container

37 center line of the paint container oriented transverse to the longitudinal center line of the paint container

38 vibration system for guides of a tinting machine

39 second replaceable cartridge