EP1286784B1 - Method for production and spray-application of a multicomponent paint - Google Patents

Abstract

The invention concerns a method for production and spray-application of a multicomponent paint in an installation comprising a main line (3) at one end of which emerges a conduit (4) supplying a base colour shade, and at the other end of which is mounted a sprayer (14), said line comprising a flow rate regulating device (10) controlling the flow of the product dispensed by the sprayer. Said method consists in: inputting at least a hardener in the main line from a secondary line; measuring in the main line the flow rate of the mixture comprising a base colour shade and hardeners; then, on the basis of the base colour shade/hardener volumetric ratio of the specific mixture, regulating the flow rate of each of the hardeners so as to obtain the predetermined volumetric ratio.

Description

The subject of the present invention is a process for producing and applying a multi-component paint by spraying, as well as an installation for carrying out this process.

A multi-component paint is constituted by a base, generally tinted, hereinafter referred to as base color, which must be mixed in a precise ratio with at least one hardener before being sprayed by any paint-splashing device.

A solution evoked by the document EP-0210 282 It would consist in mounting on the base circuit a metering pump driven by a motor itself powered by a frequency converter to vary its speed and therefore the product flow. It would also be necessary to have, on each feed circuit of the hardener, a metering pump driven by a motor - even powered by a frequency converter, the installation comprising a system capable of driving the two frequency converters to obtain the correct flow and the right mix ratio. It is also known to have, on each of the circuits, downstream of the metering pump, a flow sensor for controlling that each of the flow rates and the mixing ratio are in accordance with the desired values. The mixed product passes through a static mixer to homogenize the mixture before spraying.

The document US 5,887,975 discloses a mixing system and method for mixing one or more liquid sub-components of colors. The system includes subcomponent input lines connected to a reducing tubing. A solenoid valve "on / off" in each line is arranged to allow or prohibit the fluid from entering the reducing tubing. The reducing tubing includes the multiple inlet passages that converge to form a single outlet passage. A flow meter is in communication with the outlet passage for measuring the flow of subcomponent fluid through the tubing. Using the flow meter, a control system makes the solenoid valves open and close to meter subcomponent fluids passing from the various flow of output. From the reducing tubing, the outlet passage is connected with an integrator where the subcomponents are partially mixed. A static mixer relates to the efficiency of the integrator to completely mix the fluids.

Generally, an installation is designed to make and apply paints of different colors. It is possible in such a case to provide a block of color change or hues upstream of the metering pump. It is then necessary to perform a complete cleaning, during a change of colors, of the entire line between the color change block and the sprayer. In order to lose as little product as possible during the color change phases, the pump set is located as close as possible to the sprayer in an area classified as explosive according to the standards in force, which requires the use of approved equipment. It is also possible to provide a pump unit for each shade. The essential disadvantage of this type of device lies in the number of equipment used as well as in the unit cost of each of them. In effect, as indicated above, it is necessary to multiply the number of pump units and drives associated with them. If it is desired to limit the number of pump units, in particular to use only one group per shade, it is appropriate when changing colors to perform a complete cleaning that is long, and relatively difficult to perform and requires consumption important rinsing product such as solvent. However, because of the increase in production rates, a color change must be made quickly and under the most advantageous economic conditions possible by limiting the consumption of rinsing product.

It should be noted that these multi-component paints are increasingly used as they allow to meet environmental protection standards that require reducing solvent discharges and also reduce the energy required for cooking. Indeed, multicomponent paints comprise substantially less solvent than conventional products.

However, installations for producing and applying multi-component paint are distinct from the installations intended for the production and application of conventional solvent-based paints, these installations generally comprising a color change block, a device for flow control such as a pressure regulator or a positive displacement pump for controlling the flow rate and a flow meter. The conventional plants last type cited can not be reused immediately for realization and spray application of multi-component paints.

The object of the invention is to provide a method and an installation for the production and application by spraying of multicomponent paints, which are of a reasonable cost, which minimize the time of color change and the quantities of rinse aid necessary to clean the installation during a change of colors, and which allow the passage of interesting economic conditions of an installation intended for the realization of a conventional monocomponent paint to an installation intended for the realization and the application of a multi-component paint.

For this purpose, the method for producing and applying a multi-component paint spray in an installation according to one of claims 1 to 10 is characterized in that a flow meter permanently measures a flow rate of the basic dye mixture. / hardeners and drives a pump motor unit via a frequency converter, so that the hardener flow sent by the pump in a main line respects a predetermined volumetric ratio hue base / hardeners.

An installation for carrying out this method comprising a main line at one end of which opens, via a valve, at least one supply duct of a base color at the other end of which is mounted a sprayer, this line comprising a flow control device imposing the flow rate of the product dispensed by spraying, the main line opens at least one secondary line at the end of which opens, via a valve, at least one feed duct of a hardener, this line being equipped with a motorcycle pump unit for transferring the hardener in the main line, the latter comprising, downstream from the point of junction with the secondary line and upstream of the pressure regulator, a flowmeter which continuously measures the flow rate of the base dye / hardener mixture, characterized in that the flowmeter controls the pump unit via a variator of frequency, so that the hardener flow sent by the pump in the main line allows to respect a predetermined volumetric ratio base hue / harden ur.

The installation according to the invention is very close to a conventional installation, since it simply comprises the addition of at least one hardener line comprising a pump unit driven by a frequency converter, which joins the baseline upstream. the flowmeter. It should be noted that unlike the installations which have been described above and which constitute the state of the art, it is not necessary to provide in this case a dosing pump on the main line. and a metering pump on the secondary line, with a regulation of these two pumps, since in this case, the pump which is arranged on the secondary line is controlled from the total mixing rate which is imposed by the pressure regulator. According to one embodiment of this installation, the secondary line is equipped, at its upstream end, with a power supply unit in which open, through valves, several supply ducts base shades. In addition, the secondary line is equipped, at its upstream end, with a power supply into which open, through valves, several hardener supply ducts. According to one embodiment of this installation, the flowmeter mounted on the main line is a gearwheel flowmeter. This geared-wheel flowmeter acts in the manner of an encoder on the motor control means of the pump.

In order to achieve mixing of the base color and hardeners, a static mixer is arranged on the main line downstream of the flow meter. This static mixer may, for example, be in the form of a longitudinal propeller driven in rotation by the product flow allowing an intimate mixing of the components.

In order to allow or not the passage of base color and hardeners to the main line, two interlocking valves are arranged on the main and secondary lines immediately upstream of their point of convergence.

• un rinçage lors d'un changement de teintes ou de durcisseur et
• un rinçage lorsque la limite de durée de vie du produit mélangé est atteinte.

The installation is advantageously completed by a supply of rinsing product and air for cleaning and drying of the various pipes and components of the main line and the secondary line. There are two types of cleaning or rinsing that can be implemented:

• a rinse when changing color or hardener and
• rinsing when the life limit of the mixed product is reached.

In order to allow a rinsing during a color change, a source of rinsing product feeds pipes opening through valves at the upstream ends respectively of the main line and the secondary line. It is thus possible to clean the main and secondary lines to the outlet of the cleaning product by the sprayer. After cleaning, the product should be evacuated rinsing remaining. For this purpose, the installation comprises a source of compressed air feeding ducts opening through valves at the upstream ends respectively of the main line and the secondary line.

In order to achieve an emergency rinse when the life limit of the mixed product is reached in the main line, the source of rinse aid also feeds two pipes opening into two three-way valves mounted on the main line and on the main line. the secondary line upstream of the interlocking valves, and allowing the passage of rinsing product alternating with respectively the base color and the hardener. This makes it possible to rinse only the pipes comprising mixed product. This is made possible by the use of the three-way valves to choose between the product and the rinsing product, disposed a few tens of centimeters from the respective interlock valves mounted on the main line and the secondary line.

Finally, this installation includes a controller for controlling the various functions of the installation and a control panel forming an interface with the operator and making it possible in particular to select the colors, to adjust the flow rate of the product to be sprayed, to adjust, if is not memorized, a basic hue / hardener volume ratio, and start a hue change sequence whose different phases are managed by the controller.

In any case, the invention will be better understood from the description which follows, with reference to the single figure of the appended schematic drawing showing by way of nonlimiting example a block diagram of the installation comprising for a better understanding only a hardener line.

The installation shown in the drawing comprises a color change block 2 from which extends a main line constituted by a conduit 3. In the color change block open a number of conduits 4 via valves 5 In drawing only two ducts 4 are shown, but of course the number of ducts 4 capable of bringing different basic colors can be multiplied. In line 3, from the color change block 2 is disposed a three-way valve 6, then a 2-way interlock valve 7. Downstream of the valve 7 is mounted a flowmeter 8 with toothed wheels, then a static mixer 9, for example in the form of a longitudinal helix, a pressure regulator 10 on the supply of which is mounted a manometer 12, the pressure being controlled by the operator by actuating a display 13 or manually through a pressure gauge pressure reducer. On the main line 3 is finally mounted a sprayer 14 which, in the non-use position, can be placed in a rinsing box 15 connected to a product recovery receptacle.

In the main line 3 opens a secondary line 16, immediately upstream of the flow meter 8, via a latching valve 17. At the end of this line 16 is mounted a block 18 for supplying hardener, in which open, through valves 19, conduits 20 may bring different types of hardeners. At the output of the hardener supply block 18 are mounted a hardener presence sensor 22, then a pump 23 actuated by a motor 24 equipped with a frequency converter 26 for adjusting the speed of rotation of the pump. Downstream of the pump 23 is disposed on the secondary line a three-way valve 25. As shown schematically in the drawing, the flowmeter is connected to the control 26 of the motor to vary, through the frequency converter, the speed of rotation of the pump, to adapt it to the volume of mixture dye-hardener to achieve. The display 13 is connected to a PLC 27 acting in particular on the control of the motor 26.

The installation also comprises a source of rinsing product such as a solvent 28 connected by conduits 29, 30 respectively to the color change block 2 and to the hardener feed unit 18. These two ducts are respectively equipped with valves 32 and 34. The rinsing product source 28 is also connected respectively by conduits 35 and 36 to the main line 3 and to the secondary line 16 in which it opens at the three-way valves 6 and 25.

The installation finally comprises a source 37 for supplying compressed air supplying, via conduits 38 and 39, respectively the color change block 32 and the block supplying hardener 18, the conduit 38 opening into the color change block 2 via a valve 40 and the conduit 39 opening into the block 18 via a three-way valve 42, joining at this level the supply duct 30 of the same block solvent.

The operation of this installation is as follows. A base shade feeding the color change block 2 through an open valve 5 flows in the main line 3 through the valve 6, the valve 7, to the flow meter 8. In the secondary line 16, a hardener feeds the block 18 through an open valve 19, this hardener being driven by the pump 23 after detection by the sensor 22. The three-way valve 25 ensures the passage of the hardener as well as the shut-off valve 17 which is open . The hardener then joins the main line 3, to form with the base color a mixture whose flow rate is measured by the flow meter 8. The operator having set the desired flow rate at the display 13 or pressure gauge 12, which controls the pressure regulator, the flowmeter supplies to the pump unit 23, 24, via the motor control which acts on a frequency converter, the speed of rotation of the pump to adapt the hardener flow to the amount of it desired in the mixture. The rate of hardener delivered by the pump 23 results from the predetermined ratio between base color and hardener. The product mixture passes through the static mixer, and the pressure regulator 10 before being dispensed by the sprayer 14. If, during operation, the operator changes the overall product flow, the flow meter will provide the information to the engine control which will accordingly change the speed of rotation of the pump 23. The sprayer may be a manual or automatic sprayer mounted at the end of the arm of a robot.

When changing colors, lines 3 and 16 should be cleaned. For this purpose, after closing valves 5 and 19 previously bringing a shade and a hardener in blocks 2 and 18, it is proceeded to the sending rinsing product at the blocks, through the conduits 29 and 30, the valves 32 and 34 supplying the blocks then being open. The rinsing product flows in the main line 3 and in the secondary line 16 to the pistol 14 which is in the open position, the solvent being discharged into the rinsing box 15. After cleaning by the rinsing product, the lines 3 and 16 are dried with compressed air from the source of compressed air 37, the air being brought to the level of the color change blocks 2 and feeding hardener 18 through the conduits 38, 39, the valves 40 and 34 being open, and the three-way valve 42 being switched to allow the passage of air With this assembly, it is possible to rinse only the basic circuit in case there is no change in hardener.

If there is a risk of hardening of the product constituted by the mixture of base color / hardener in line 3, it is necessary to carry out an so-called emergency rinsing, which requires only the rinsing of the part of the pipe comprising the product. mixed. For this purpose, the three-way valves 6 and 25 are tilted in the position in which they allow either the passage of the base color and a hardener, but rinsing product.

The controller 27 controls the various functions of the installation and the display 13 or control panel forming an interface with the operator makes it possible in particular to select the colors, to adjust the flow rate of the product sprayed, to adjust, if is not memorized, a volume ratio of basic tint / hardener and start a sequence of change of colors whose different phases including cleaning are managed automatically. The PLC also reads the value of the total flow rate of the mixture circulating in the installation.

As is apparent from the foregoing, the invention provides a great improvement to the existing technique by providing a method and an installation for producing and spraying a two-component paint consisting of a base shade and a hardener, allowing the implementation of a conventional installation on which can be grafted a hardener feed line.

In variants, not shown, the main line could supply a second sprayer itself equipped with its pressure regulator, or the installation could include several secondary lines of hardeners.

Claims (11)

1. An installation for making up and spray-applying a multi-component paint consisting of a base shade and at least one curing agent, comprising a main line (3) into one end of which there leads, via a valve (5), at least one feed duct (4) for a base shade and at the other end of which there is mounted a sprayer (14), said line (3) comprising a flow rate regulating device (10) setting the flow rate of the product distributed by spraying, the main line (3) having at least one secondary line (16) leading into it, into the end of which there leads, via a valve (19), at least one feed duct (20) for a curing agent, said line (16) being equipped with a motor-driven pump (23, 24) intended to transfer the curing agent into the main line (3), the latter comprising downstream of the junction with the secondary line and upstream of the flow rate regulator (10) a flow meter (8) which continuously measures the flow rate of the base shade/curing agent mixture,
   characterised in that the flow meter (8) drives the motor-driven pump through the intermediary of a frequency variator (26), such that the flow rate of curing agent sent by the pump (23) into the main line (3) allows compliance with a predetermined base shade/curing agent volume ratio.
2. An installation according to claim 1, characterised in that the main line (3) is equipped, at its upstream end, with a colour changing block (2) into which there lead, by way of valves (5), a plurality of base shade feed ducts (4).
3. An installation according to one of claims 1 and 2, characterised in that the secondary line (16) is equipped, at its upstream end, with a supply block (18) into which lead, by way of valves (19), a plurality of curing agent feed ducts (20).
4. An installation according to one of claims 1 to 3, characterised in that the flow meter (8) mounted on the main line (3) is a gearwheel flow meter.
5. An installation according to one of claims 1 to 4, characterised in that a static mixer (9) is disposed on the main line downstream of the flow meter (8).
6. An installation according to one of claims 1 to 5, characterised in that two switch-on valves (7, 17) are disposed on the main line (3) and secondary line (16) immediately upstream of the meeting point thereof.
7. An installation according to one of claims 1 to 6, characterised in that it comprises a source of rinsing product such as a solvent (28) supplying ducts (29, 30) leading by way of valves (32, 34) into the respective upstream ends of the main line (3) and of the secondary line (16).
8. An installation according to claims 6 and 7, characterised in that the rinsing product source (28) further supplies two ducts (35, 36) leading into two three-way valves (6, 25) mounted on the main line (3) and the secondary line (16) upstream of the switch-on valves (7, 17) and allowing solvent to pass alternately with respectively the base shade and the curing agent.
9. An installation according to one of claims 1 to 8, characterised in that it comprises a compressed air source (37) supplying ducts (38, 39) leading by way of valves (40, 34) into upstream ends respectively of the main line (3) and the secondary line (16).
10. An installation according to all of claims 1 to 9, characterised in that it comprises an automatic controller (27) controlling the various functions of the installation and a control panel (13) forming an interface with the operator and in particular allowing shade selection, setting of the flow rate of the product to be sprayed, setting, if it has not been saved, of a base shade/curing agent volume ratio, and initiation of a shade changing sequence, of which the various stages are managed by the automatic controller.
11. A method of making up and spray-applying a multi-component paint in an installation according to one of the preceding claims, characterised in that the flow meter (8) continuously measures the flow rate of the base shade/curing agent mixture and drives the motor-driven pump (23, 24) through the intermediary of the frequency variator (26), such that the flow rate of the curing agent sent by the pump (23) into the main line (3) complies with the predetermined base shade/curing agent volume ratio.

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