WO2023180766A1

WO2023180766A1 - Powder colourant dispensing and mixing apparatus

Info

Publication number: WO2023180766A1
Application number: PCT/GB2023/050759
Authority: WO
Inventors: Anthony David George Rhoades; Samuel Paul CORNISH-EVANS; Jiri DOHNALEK
Original assignee: Savaqwa Limited
Priority date: 2022-03-25
Filing date: 2023-03-24
Publication date: 2023-09-28

Abstract

A powder colourant dispensing apparatus suitable for use in an autonomous or semi-autonomous paint dispensing machine, the powder colourant dispensing apparatus comprising: a rotating carousel (120); wherein the rotating carousel comprises a first receptacle (131), the first receptacle comprising a first powder colorant substance and a second receptacle (131), the second receptacle comprising a second powder colorant substance; the rotating carousel further comprising an opening; a controller taking as an input, information about a required characteristic of a colourant product; wherein the controller calculates the required quantities of the first and second powder substances to form the colourant product, and wherein the controller can control the rotation of the carousel to output the required quantities of the first and second powder substances via the opening. Thus, the autonomous dispensing machine is able to dispense a wide variety of paint finishes and types in a just in time manner, in any quantity required.

Description

Powder Colourant Dispensing and Mixing Apparatus The present invention relates to an autonomous powder colourant dispensing and mixing machine, where resulting paint product can be produced just in time and in any colour, in any quantity and in any dilution and/or finish desired. Background In industrial paint mixing scenarios, powdered pigments are poured into a large vat of raw paint ingredients – usually poured manually from bags. Wherein Industrial paint mixers drip tints into a bucket, or container, of a base paint and stir them together via manual, or mechanical means. The base paint forms the bulk and is the foundation that other elements, known as pigments or tints, are added to make a useable paint product. A base makes the film of the paint, opaque, harder, and elastic & prevents formation of shrinkage cracks. Existing decorative paint human-operated systems, such as those found in hardware stores, simply add colour pigments to a ready-mixed base paint, this is known as ‘tinting’. If you open a can of base paint, it usually looks white in appearance. However, the bulk of base paint is actually clear. The clear portion can integrate with the materials found in the colorant, essentially accepting the solids, creating the final product. That causes the hue of the paint to change, as the colorants are incorporated into the clear material. There are many different kinds of paint bases, the main difference being the amount of white pigment and so which can incorporate the most colorant. An example of such a tinting system has been disclosed in WO/2017/081117 “Tinting Machine and Method for Dispensing Colorant into a Paint Container with Base Paint”, which describes a tinting machine with a dispenser head for dispensing one or more colorants into a base paint. Commercial systems include the AkzoNobel-Dulux Mixlab (used in Homebase in the UK) and the Sherwin Williams-Valspar lab (used in B&Q in the UK). Another alternative system of the art is the ALFA s.r.l Paint Sample Dispensing Machine, a description of which can be found here https://www.alfadispenser.com/color-tester-3-0/ and which has been disclosed in WO2016166737A1 “Dispensing Machine, In Particular For Producing Paint Sample”. Summary of Invention According to a first aspect of the present invention, there is provided a powder colourant dispensing apparatus suitable for use in an autonomous or semi-autonomous dispensing machine, the powder colourant mixing apparatus comprising: a rotating carousel; wherein the rotating carousel comprises a first receptacle, the first receptacle comprising a first powder colorant substance and a second receptacle, the second receptacle comprising a second powder colorant substance; the rotating carousel further comprising an opening; a controller taking as an input, information about a required characteristic of a colourant product; wherein the controller calculates the required quantities of the first and second powder substances to form the colourant product, and wherein the controller can control the rotation of the carousel to output the required quantities of the first and second powder substances via the opening. Preferably, wherein the opening is fluidly connected to an internal catchment chamber. Further preferably, wherein the powder colourant dispensing apparatus further comprises a piston, the piston having an outer side surface, which piston is longitudinally and movably arranged in the internal catchment chamber, such that an annular space is defined by the outer side surface of the piston and the inner surface of the internal chamber. Wherein as the carousel is rotated, the piston is lowered to extract the powder colourant substance from the opening in a required amount. Advantageously, the carousel further comprises a collection receptacle, the collection receptacle fluidly joined to the internal chamber and preferably wherein the collection receptacle may be a hopper. There is also provided a method of forming a powder paint formulation ready for dispensing, comprising the steps of: taking as an input, information about a required characteristic of a colourant product; calculating the required quantities of a first and second powder substances to form the colourant product, rotating a chamber to first position; dispensing a calculated quantity of the first powder colourant material into a receptacle; rotating the chamber to a second position; dispensing a calculated quantity of the second powder material into the receptable; and outputting the first and second powder materials. Preferably wherein the controller can further control the timing of the first and second dispensers to create a mix of the first colourant substance and the second colourant substance. Further preferably, wherein injected air is used to create a mix of the first colourant substance and the second colourant substance and/or a mechanical mixer unit. Thus, the autonomous dispensing machine is able to dispense a wide variety of paint finishes and types in a just in time manner, in any quantity required. A choice of multiple colours may be entered via an input, such as a keypad or touch enabled display screen, or may be sent to the autonomous paint dispensing machine via a wired or wireless communication to the cloud. The system controller may need to perform a conversion from an input colour space to an internal colour space and further, may need to account for a white dilution medium. Thus, the autonomous dispensing machine can dispense a wide variety of paint finishes and types in a just in time manner, in any quantity required. Preferably, the first and/or second receptacles may be formed from a flexible bag, the flexible bag provided with an airtight valve outlet sealed to the flexible bag and wherein the flexible bag is housed within a substantially rigid frame within the autonomous or semi-autonomous dispensing machine. Advantageously providing lightweight and reusable/recyclable paint cartridges that can be inserted easily by a user and carry RFID or other security markings to ensure their correct use. There may also advantageously be provided one or more cleaning fluid supply conduits, wherein the one or more cleaning fluid supply conduits are opening in the one or more dispenser heads at a cleaning fluid inlet in the internal chamber. A user may also be able to check the output characteristics of the colourant product, can adjust the characteristic and/or decide whether to proceed with the dispensing of the colourant product. Thus, advantageously giving a user full flexibility and control over the output. The first colourant substance may be one or more of a paint, a paint concentrate, an ink, an ink concentrate, a pigment, a coloured material, a powder. Thus, the present invention provides an intelligent integrated paint machine, where paint is produced just in time and in any colour, in any quantity and in any dilution and/or finish desired. This is a world first product and process for the paint industry, where only the semi-automated colour mixing/tinting of ready-mixed paint currently exists. DESCRIPTION OF FIGURES Embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings, in which: Figure 1 –is a process flow diagram showing a first embodiment of a colourant processing method of the present invention; Figure 2 – is a flow diagram showing a method of finding wavelengths of a paint and the mix they will produce for a given surface; Figures 3a and 3b – are schematic diagrams of a colourant dispensing solution, according to a first embodiment of the present invention; Figure 4 - is a schematic diagram of a vortex/swirl mixing chamber which may be used with the embodiments of either Figure 3. Figure 5 – is a flow diagram showing an output verification method, according to an embodiment of the present invention. The present techniques will be described more fully hereinafter with reference to the accompanying drawings. Like numbers refer to like elements throughout. Parts of the colour machines are not necessarily to scale and may just be representative of components of the colour machines, or other described entities. DETAILED DESCRIPTION Figure 1 is a process flow diagram showing a first embodiment of a colourant processing method of the present invention. The steps of the process flow in Figure 1 shall herein be described. Process Start: Step 1: Obtain Required Output Colour values, volume and finish of paint required Via a system controller 22, such as that described in Figures 3 to 4, an input can be obtained, which describes the characteristics, such as colour of a paint or ink to be mixed, as well as the consistency, such as viscosity or solubility (see Step 5 below). For example, a system user would simply be asked via an input (such as keypad or a touch capable display screen), the volume, type (such as Matt, or Silk, Indoor or Outdoor) and colour shade of the paint to be mixed. The user may provide a Pantone reference, an RGB colour vector, or other colour space references including wavelengths, which are handled in Step 2 following. Step 2. Convert Required Output Colour values to Machine values (optional step) In colourant mixing and/or printing apparatus, colour conversion is often required. Many colour space systems are used in the art, for example use RGB, CMY, Pantone. For example, in the art, a RGB input is usually inputted by a user, or in a file, comprising a vector of three numbers varying between 255 and 0. Each of these values determine the intensity of each of the three colours. Many equations are known for converting RGB to CMYK, for example. An alternative conversion method is described with reference to Figure 2. Step 3: Account for White However, in the prior art, white has never been accounted for with a CMYK system, as it assumes that white is the printing medium, base paint, or surface. For the invention of the present system to work effectively, it is necessary to convert an RGB vector input into a CMYK and W output (CMYKW). Using the program of the present invention, which can be found in Appendix A, the system controller 22 (of Figure 3-4) of the present invention can calculate CMYKW ratios for any inputted RGB vector, as seen in the above example. An alternative method is described with reference to Figure 2. Step 5 : Determine the volume and finish of paint required Many chemical and/or powder elements are also used to comprise a single sample of a particular type and finish of paint. For example, waterborne paints most often use acrylic emulsion polymers as binders. Solvent based resins come in a very wide range of types. Solvents are also used that act as a ‘carrier’ for the pigments and resins – the solvent may be organic (such as Mineral Turps) or may be water. Various additives are also used to enhance certain properties such as ease of brushing, mould resistance, scuff resistance, and drying time. Dependent on the required volume and finish of paint, the required volume of materials such binders, solvents and additives etc need to be calculated in precise quantities. Step 7: Output values to a colour production machine The output thus may then be utilised to deploy the resulting values using a system controller 22 of Figures 3-6 and onto a valve, or motor control system 44a, 44b, attached to each paint cartridge 5a, as shown in Figures 3-4 to dispense the required amounts of each element required. They can either be calculated by a controller within the machine, in the cloud, or via user input, as shall be herein described. End of Process However, it should be noted that when doing colour conversions, it may be physically impossible to create certain colours present in different colour-spaces. For example, the sRGB colour space is the standard RGB (red, green, blue) colour space that HP and Microsoft created cooperatively in 1996 to use on monitors, printers, and the World Wide Web. It was subsequently standardized by the International Electrotechnical Commission (IEC) as IEC 61966-2-1:1999. sRGB is also usually the assumed colour space for images that are neither tagged for a colour space, nor have an embedded colour profile. The sRGB colour space is quite restrictive and comprises less colour variations than the RGB space, for example. When compared to CMYK, the RGB model is far better as it has a wider colour spectrum. The RGB spectrum includes fluorescent greens and blues. In the CMYK system, fluorescent colours are difficult to reproduce accurately. This results in a mismatch between RGB colours and CMYK colours. So, when certain colours are converted, some may not be accurately reproduced. This inaccuracy is considered later, as described with reference to the method of Figure 7. In Figure 2, there is shown a method of finding the wavelengths of a paint, and the mix they will produce for a given surface, according to a second embodiment of the present invention. To effectively mix paints, far more so than with inks, it is very important to consider how the spectral reflectance of paints will be transmitted to the eye as the subtractive nature of paint mixing and that the high opacity can lead to the darkening of mixed paints, or variations, on a particular surface. To counteract this, a process has been created for more accurate mixing of paints for a given surface. Process Start: S1 – Obtain input colour reflectance values. The input colour reflectance values may either be directly obtained from a scan of a colour using a spectrophotometer scanner as known in the art or may be obtained by a user inputting the colour they want using an image file (such as a .png or .jpg file), or by using a Pantone refence, RGB colour reference, or a HEX number, for example. In the latter case, the user input colour references need to be converted to reflectance values and so Step 2 following needs to be used. S2 - Obtain Reflectance values of input colours (if required). Using the Lagrangian formulation and Newton’s method, the reflectance values of various colour values can be obtained. Whether by directly using a handheld scanner in Step 1, or by following both steps 1 & 2, the result needed before Step 3 is a 36x1 array of reflectance values of the input colour in the 380nm-730nm wavelength range. S3. Obtain the nearest mix ratio of paints loaded into the machine. This would be implemented using a ‘look up’ table of the reflectance values of the colourants loaded into the machine, the ratios needed for each RGB colour, and would be in the form of a 36x1 array for each colourant. A look up can then be performed to find the nearest mix ratio of paint powders loaded into the machine to result in the requested colour. S4. Find base wavelengths/reflectance values. So for the colour input, the ratios of each mix is required and thus the reflectance values of those base colours. For example, for a specific output colour if you need the below sub colours in the following ratios: R : 1 Yellow : 2 Blue : 4 Total = 1+2+4 = 7 Then the resulting reflectance wavelength calculation would look like this: RED[i] ^1/7 YELLOW[i]^2/7 BLUE[i]^4/7 This results in a new set of arrays for the ratios of colours required to make the output colour. S5. Create the final reflectance value of the output colour. The above ratio calculation is then applied to each reflectance element in the 36x1 array for each sub colours, resulting in combined reflectance curve for the resulting colour. For example for the above example the following array would be produced: RED[i] ^1/7 YELLOW[i]^2/7 BLUE[i]^4/7 RED[ii] ^1/7 YELLOW[ii]^2/7 BLUE[ii]^4/7 RED[iii] ^1/7 YELLOW[iii]^2/7 BLUE[iii]^4/7 RED[iv] ^1/7 YELLOW[iv]^2/7 BLUE[iv]^4/7 …………… …………..

S6. Convert the Total Reflectance Array to a Linear RGB colour space. This step multiplies the output of Step 5 (the combined reflectance curve array) with a T Matrix (a Light Scattering Matrix, as known in the art), in order to result in a Linear RGB colour space output. S7. Perform a Gamma Correction to the resulting Liner RGB. This step corrects for any brightness adjustments needed. S8. Convert Linear RGB to sRGB (or whatever is needed to display the output colour to the user). Certain user displays required certain colour spaces as an input to be able to display a colour, so this step would be needed to be modified for the specific implementation. End of Process Due to the possible limitations of the colourants held in the machine, that in they might not be able to be mixed in any way that could form the precise input colour requested. Thus, the colour calculated in step 5 might be a “nearest colour” or “approximate colour”. Thus this “nearest colour” or “approximate colour” could then be displayed to the user to ensure the user is happy with the “nearest colour” or “approximate colour”. Figures 3 and 3b – show schematic diagrams of a colorant dispensing apparatus, according to a first embodiment of the present invention. There is shown a circular domed carousel 120, which can take up to 6 different paint colours in individual compartments 131. The carousel comprises a lower portion 122 and an upper portion 121, separated by a circular side wall 132. It should be clear to someone skilled in the art that the carousel could be, for example, hexagonal, and may also have a different number of compartments. The side portion 132 of the carousel 120, further comprises gear teeth 126, which interact with a main gear 125, which enables rotation of the carousel 120, around a central pivot 128, in a controlled manner. The control means used to rotate the carousel 120 doesn’t necessarily have to be gears, any suitable mechanical or electrical methodology could be used, such as magnets or motors. A system controller, such a microprocessor, or FPGA, can be used control the colorant dispensing apparatus, as described in further detail with regards to Figure 1. The six compartments 131 inside the carousel 120, could either be used for powder paints, or concentrated paints or inks. If concentrated paint or ink is used, the entire carousel 120 would need to be fluidly sealed. The carousel is rotated using the main gear 125, until the lower piston 127 is below the colour to be selected. The lower piston 127 then lowers to extract powder or paints from the lower opening 133 of the relevant compartment 131 in a proportion needed for a further mixing or compaction stage, for example using the mixer described in Figure 4. The colours are stored inside the piston casing – see Figure 3b. For example, the lower piston 127 would be lowered in coordination with the amount of each colour that's required, so for a total amount of one part white two parts black, there would be a rotation between the white compartment and the black compartment and twice the amount of black would be released, to then be mixed with the white. The open section 123 has a chamfered side 124 in which pushes the paints off into a hopper or a funnel (not shown) or may lead directly to the input of the mixer as described with reference to Figure 4, or any suitable mixer known in the art and suitable for a particular application. The carousel 120 has an open side 123 and this is where the dry or concentrated paint is pushed out by the chamfered edge 124 and the piston into a hopper, or a funnel (not shown). In either case, lower piston 127 can be used on its own to extract powder or paints from the relevant compartment 131. Alternatively, upper piston 133 and lower piston 127 could be used together to compress said paint, if needed (to make a compact powder tablet for example). The lower and upper pistons are lowered and raised by the upper piston gear 129 and lower piston gear 130. This embodiment can also be used with paint concentrates and other deposition materials. Figure 4 – is a schematic diagram of a vortex/swirl mixing chamber which may be used with the embodiments of either Figure 3a & 3b. Figure 4 comprises a swirl chamber 160, with four air inputs 162, 163, 164, 165 offset on the side of the swirl chamber 160, which in operation to create a tornado affect. A fifth air inlet 167 at the top of the swirl chamber 160, drawers air down to create a Venturi effect at the lower end. Powder paint, or paint concentrate is injected via separate hydraulic lines 169 into the main chamber 160 and is mixed by the air in the vortex and output by a nozzle output valve 168. Paint pigments are powders of typically small size that tend to ‘stick together’ to form clumps or agglomerates. These must be broken down into separate particles that must then be wetted by resin and additives to stop them sticking together again. This is the process of dispersion. High speed mixers are used for combining materials and dispersing most pigments. Thus, if paint concentrates are being used, then improved performance may be obtained by using an atomiser on each input 169 in order to atomise the paint so that it mixes properly and doesn’t stick or attach to the sides of the swirl chamber 160. The inner lining of the swirl chamber 161 could also be made from non-stick material, such as PTFE, so that the paint doesn’t stick to it the inside of the swirl chamber 160. The chamber 160 itself could be made from metal or another type of plastic, whichever suits the scale and application of the vortex mixer. The air inputs 162, 163, 164, 165 are pressurised. If you needed to mix paint powder the air inlets 162, 163, 164, 165 could also take in pressurised water, solvents, binders or stabilisers, or pressurised white paint, depending on the application. In some applications, pigments need to be added slowly to a portion of the liquid paint components, with the mixer running, so there is a need to accurately enable the control of the paints flow rate. By controlling the flow rate, the system can control the ratios and amounts of the colours very easily and accurately. It should be clear to those skilled in the art, that many means can be used to control the flow of the colour mixer system as shown in Figures 3 & 4, such as solenoids, hydraulic pumps and/or actuator valves. Any combination of said devices can be used to dispense a mixture of chemical, such as solvents, binders and stabilisers, concentrates and water, or other fluids for the correct mixing application. Acrylic based paints can be used, as the paint is water based and can be heavily diluted to improve its flow. All paints have colour pigments in them; these pigments are what gives the paint its colour. Watering the paint down reduces the density of the pigments in the paint so, when the paint mixes, it may not produce the exact colour on first time use, so a feedback loop, as described below with reference to Figure 5 below might need to be deployed. It will be appreciated that if using more than one coloured paint in a single mixer unit of any of the embodiments from Figures 3 to 4 included, the internal chambers and fluid outlets of the mixer units and/or related pipe work may need to be cleaned after each dispensing operation to avoid mixing of colorant from a previous dispensing operation with those of a succeeding operation. Such purging and cleaning operations are discussed in other co- pending applications by the Applicant. It should be clear to someone skilled in the art that there are various mechanical options for mixing the required quantities and finish of paint required, depending upon the application. A systems controller (not shown) may be in communication with a cloud network, the edge, such as remote resource, which may be a tablet, smartphone or laptop when the present techniques are applied. The edge may be a tablet controlled by a user or operator. In the present example, it will be appreciated that the cloud may comprise any suitable data processing device or embedded system which can be accessed from another platform such as a remote computer, content aggregator or cloud platform which receives data posted by the colourant dispensing machines of the present invention. Figure 5 is a flow diagram showing an output verification method, according to an embodiment of the present invention. There is shown the following method steps: Method: S1. Obtain the required input colour values, type and volume of paint required S2. Transform to the nearest output colour value (if required) and display the result to a user. This step could use the methods as described in Figures 1, or 2 of the present invention, or any other suitable colour transform method as known in the art. S3. Check with the user if they want to proceed, if YES, continue with the following steps. If NO, finish process. S4. Calculate required amounts of each colourant and/or whether dilution, solvents, binders or other suitable base materials are required for the specific paint application as input in Step S1. S5. Place (or mechanically move) a catch tank under output nozzles S6. Run the deposition program to dispense the required amounts of each material, according to the embodiments described in Figures 3 & 4. S7. Mix outputted paint using embodiments as described with reference to Figures 3 & 4 inclusive (if necessary – optional step) S8. Scan the paint mixture produced using an optical colour scanner as known in the art. S9. Re-adjust the mix, based on user inputted adjustments (if necessary – optional step) S10. Re-run Steps S3 to S7 End of method Thus, in use, a user can input a hex value into the mixing machine for a paint colour that is required, or via another method, such as uploading an image or a scan of a colour, for example. Then the mixing machine, understanding what colourant materials and other base materials such as solvents, binders and dilutants it is carrying, can supply the user with the nearest colour and/or type and volume of paint that can be output and the user can accept or reject that colour and/or the presented format and/or volume options. In operation, the depositing and mixing systems of the present invention may house two, three, four or more flexible bags, or colourant cartridges, containing a material for dispensing and/or mixing, the material for dispensing contained within each flexible bag being an ink or paint selected from a cyan, magenta, yellow, black, white, green, blue or red colour. Other colour space colourants can be used. The colourant materials can be powder paints, inks, concentrated paints or inks, or any other formulation of colourant materials. The flexible bags may be housed in a substantially rigid frame or using other paint cartridge means and would be especially adapted for the colourant being mixed. The hoses, valves and mixing solutions, such as solvents, binders, stabilisers or water also being chosen for the specific application. It will be clear to one skilled in the art that many improvements and modifications can be made to the foregoing exemplary embodiments without departing from the scope of the present technique.

Claims

CLAIMS: 1. A powder colourant dispensing apparatus suitable for use in an autonomous or semi- autonomous dispensing machine, the powder colourant dispensing apparatus comprising: a. a rotating carousel; b. wherein the rotating carousel comprises a first receptacle, the first receptacle comprising a first powder colorant substance and a second receptacle, the second receptacle comprising a second powder colorant substance; c. the rotating carousel further comprising an opening; d. a controller taking as an input, information about a required characteristic of a colourant product; e. wherein the controller calculates the required quantities of the first and second powder substances to form the colourant product, and wherein the controller can control the rotation of the carousel to output the required quantities of the first and second powder substances via the opening.

2. A powder colourant dispensing apparatus according to claim 1, Wherein the opening is fluidly connected to an internal catchment chamber.

3. A powder colourant dispensing apparatus according to claim 2, wherein the powder colourant dispensing apparatus further comprises a piston, wherein the piston is longitudinally and movably arranged in the internal catchment chamber.

4. A powder colourant dispensing apparatus according to claim 3, wherein as the carousel is rotated, the piston is lowered to extract the powder colourant substance from the opening in a required amount.

5. A powder colourant dispensing apparatus according to any preceding claim, wherein the carousel further comprises a collection receptacle, the collection receptacle fluidly joined to the internal chamber.

6. A powder colourant dispensing apparatus according to claim 5, wherein the collection receptacle may be a hopper.

7. A powder colourant dispensing apparatus according to any preceding claim, wherein the carousel is fluidly sealed.

8. A powder colourant dispensing apparatus according to any preceding claim wherein the carousel rotates using gears, or other means.

9. A powder colourant dispensing apparatus according to any preceding claim, further comprising a mixer unit.

10. A method of forming a powder paint formulation ready for dispensing, comprising the steps of: a. taking as an input, information about a required characteristic of a colourant product; b. calculating the required quantities of a first and second powder substances to form the colourant product, c. rotating a chamber to first position; d. dispensing a calculated quantity of the first powder colourant material into a receptacle; e. rotating the chamber to a second position; f. dispensing a calculated quantity of the second powder material into the receptable; and g. outputting the first and second powder materials.