JP2011020107A - Method and apparatus for mixing multiple liquid coating materials - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To supply the accurate amounts of respective liquids to a mixing apparatus even when there are three or more liquids and by any mixing ratio, and to mix coating materials by a highly accurate mixing ratio. <P>SOLUTION: A plurality of cylinders of a cylinder pump 2 driven by a servo motor for discharging a fixed quantity corresponding to a pulse number are connected and simultaneously driven, the liquids supplied from a supply liquid container into the respective cylinders are discharged in a discharge process, respective discharge paths are communicated with a mixer 1 through respective switch valves, and the other paths of the switch valves are configured to return flow to the supply liquid container of the respective cylinders. The switch valve is controlled so as to perform discharge to the mixer side during the pulse number corresponding to the required discharge amount of the respective liquids and to return the flow to the supply liquid container during the other case in the discharge process. After supplying the respective liquids to the mixer, they are mixed and agitated by an agitation means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

In the present invention, when a main agent and a curing agent are mixed and used at a certain ratio as in a reactive multi-component paint, an accurate mixing ratio can be easily obtained, and particularly effective with three or more liquids including a solvent. The present invention relates to a method and apparatus capable of mixing.

In the field of spray coating, multi-component paints, such as two-component urethane coating and two-component epoxy coating, have excellent coating film performance, as well as features such as reduction of solvents, and in industrial fields. The use of is expanding. However, what has always been a problem is that accurate mixing is required at the time of use, which is one of the major burdens on the operator.

In many of these paints, it is necessary to mix the main agent and the curing agent, add a solvent if necessary, and adjust the viscosity of the paint to be suitable for spray coating. Usually, the method of mixing and supplying to a sprayer just before using will be taken. Many methods and apparatuses have been proposed for accurate mixing, and it is important to be able to accurately supply each liquid to be mixed to the mixing means.

When supplying a liquid, the quantitativeness and accuracy depend on the type of supply device represented by a pump. In general, a positive displacement pump has a discharge amount per cycle whether it is a rotary type or a reciprocating type, and the discharge amount can be obtained from the drive amount. However, the supply amount of each liquid in the multi-component paint is required to have high accuracy and cannot vary depending on the operation position. In other words, fluctuations at the time of switching that are unavoidable in a reciprocating type or the like become a serious problem.

Therefore, a gear pump is employed as a means that requires such a highly accurate quantitative property when a quantitative property is obtained with a pump. In the case of a gear pump, since a discharge amount proportional to the rotation angle is obtained, the rotation speed (angle) of the gear pump for each liquid is set to a ratio that matches the mixing ratio according to the ratio of the liquid supplied. It is configured to be driven simultaneously and supplied to the mixer (see Patent Document 1).

However, in the case of gear pumps, the supply liquid such as the main agent and curing agent has various properties like a multi-component paint, and it is difficult to maintain quantitativeness when the viscosity is low or the thixotropy is high. It itself has a problem that it is complicated, requires accuracy, and costs high.

A syringe is known as a simple means for reliably supplying a fixed amount. Similarly, a cylinder pump that uses a piston to discharge the liquid sucked into a cylinder uses a pulse signal to drive the piston. By using a servo motor that controls the drive amount, there is a feature that enables quantitative discharge with extremely high accuracy. However, such a technical means also requires a cylinder pump for each liquid to be mixed in the case of a multi-component paint, and controls the driving of each cylinder pump according to the mixing ratio. There is a problem.

On the other hand, as a means to cope with the case where the quantitative property of the pump is not sufficient, at the stage of supplying each of the multiple liquids to the mixer by the supply device, a flow meter is provided in the flow path to measure the actual supply amount, A method is adopted in which the measured value is supplied while being fed back to the drive control device of the supply device so that the flow rate matches the required mixing ratio. (See Patent Document 2)

Such a flow rate measurement method needs to always control the supply device based on the measured value, and the control is not only complicated, but also requires maintenance to maintain the reliability of the measurement device itself, etc. Many problems are inherent. In particular, in order to accurately measure the flow rate of paint having viscosity and thixotropy, it is necessary to use an expensive Coriolis flow meter, and there are still aspects that are difficult to adopt commercially.

Japanese Patent Publication No. 05-041305 Japanese Patent Publication No. 03-018502

As described above, mixing of multi-component paints requires that each liquid be quantitatively supplied with high accuracy and be compatible with various mixing ratios. However, increasing the accuracy of any technology increases the cost, and the device itself Maintenance is also a burden on the workers. Furthermore, even if the multi-component paint itself is a paint in which additives and accelerators are mixed in addition to the usual main agent and curing agent, liquids that do not affect the reaction can be mixed in advance and handled as two parts. In painting, it is often important to improve finish accuracy by lowering the viscosity of the paint, and in that case, a solvent must be mixed according to various conditions.
In such a situation, the amount of liquid to be mixed further increases, which further increases the complexity and cost of the aforementioned apparatus.

In the present invention, even when there are three or more liquids as described above, the liquid can be supplied to the mixing device in an accurate amount at any mixing ratio, and the paint can be mixed at a highly accurate mixing ratio. Accordingly, it is an object of the present invention to obtain a suitable multi-component paint supply device by obtaining a mixing device that can perform various mixings in a multi-component paint widely and thereby does not cost much.

A plurality of cylinder pumps that are driven by a servo motor and deliver a fixed amount according to the number of pulses are connected and driven simultaneously, and the liquid supplied from the supply liquid container is discharged into each cylinder in the discharge process. And the other passage of the switching valve is returned to the supply liquid container of each cylinder according to the discharge amount required for each liquid in the discharge process. During the number of pulses, the switching valve is controlled so that the other discharge liquids are returned to the supply liquid container, and each liquid is supplied to the mixer and then mixed and stirred by the stirring means.

The apparatus is a multi-component paint mixing apparatus comprising a cylinder pump, a supply means to the cylinder pump and a discharge liquid from the cylinder pump, and a mixer having a mixing means. The cylinder pump is disposed in the cylinder. A number of pump cylinders that actuate pistons by a servo motor whose required amount is driven by pulse signals to drive the supplied liquid are arranged, and are driven simultaneously by the same servo motor. A switching valve is connected to each discharge port, one outlet of the switching valve is connected to the mixer, and the other outlet is connected to a liquid container of a supply means for supplying each liquid to each pump cylinder. Based on a preset program, the time for connecting each liquid discharged from each pump cylinder to the mixer and the time for returning to the liquid container is controlled. A control device for providing.

Each pump cylinder of the cylinder pump is provided with a control valve that communicates with the pump cylinder when each liquid from the supply means is introduced, and shuts off the discharge liquid from the supply means to the liquid container when discharged.

With the above configuration, each liquid to be mixed can be accurately supplied to the mixer, the functions of the multi-component paint can be maximized, and the paint can be stably supplied in spray coating, resulting in stable paint quality. Can keep. In particular, even three liquids including a solvent can be quantitatively mixed without any problem, and a multi-liquid paint suitable for the coating conditions can be supplied to the spray gun.

Since the cylinder pump requires only one drive source and a large number of pump cylinders, a supply device for mixing can be obtained without increasing the cost even with a large number of liquids. Any mixing ratio can be easily accommodated by changing the operation sequence of the switching valve, and can be used as a wide range of mixing and supplying devices.

Basic configuration diagram of the apparatus used to implement the present invention Sequence diagram for explaining the basic operation of the present invention Explanatory diagram showing the mechanism of quantitative supply using a pump cylinder Configuration diagram of the device explaining the operation of the pump cylinder Basic configuration diagram of an apparatus shown as an application example of the present invention

A specific configuration of the present invention can be shown in FIG. A cylinder pump 2 is used as a pump for supplying each liquid to the mixer 1 in order to mix multiple liquids. The cylinder pump 2 includes three pump cylinders 2a, 2b, and 2c. Although not shown, each pump cylinder is simultaneously and integrally driven by one common driving device.

As shown in FIG. 3, each pump cylinder is composed of a cylinder 25 and a piston 26, and a control valve 3 is provided in an inlet passage 24 for feeding liquid into the cylinder 25, and suction is performed in the cylinder 25. The liquid thus discharged is discharged from the discharge port 28 when the control valve 3 is closed and the piston 26 is operated, and the discharge is quantified by the amount of movement of the piston 26. In order to control the discharge amount, the movement of the piston 26 is transmitted to the ball screw 12 by the rotation of the servo motor 11 whose rotation is controlled by a pulse signal, as shown in FIG. A configuration in which the body 13 moves up and down and the piston 26 fixed to the moving body 13 moves up and down is generally used.

Since the discharge amount from the cylinder is pushed out in proportion to the movement amount of the piston 26, the discharge amount corresponding to the number of drive pulses of the servo motor can be controlled by the servo motor 11 in which the movement amount is accurately set. Yes. This type of pump has other necessary requirements such as airtightness between the cylinder and the piston, but their configuration is also widely known and is not particularly limited, and thus detailed description thereof is omitted.

The control valve 3 provided on the inlet passage side of each cylinder pump is connected to the discharge side of the auxiliary pump 5 that sucks and discharges the liquid contained in the liquid container 4 on the inlet side, and the outlet side to the cylinder. The communication is switched between the communication and the passage 7 returning to the liquid container 4, and it is controlled whether the liquid discharged from the auxiliary pump 5 is sent into the cylinder 25 or returned to the liquid container 4. The supply means shown here as the auxiliary pump 5 is not limited to this, and may be another supply means. Therefore, the control valve 27 may be an open / close valve to the cylinder side as long as the supply means is stopped at a predetermined discharge pressure or is returned to the suction side by closing the discharge passage.

In FIG. 1, each pump cylinder 2 having the above-described configuration and function and the configuration of its supply circuit are distinguished by adding subscripts a, b, c to the liquids to be mixed, and the main agent a, the curing agent b, and the solvent 3 liquids of c. Switching valves 6a, 6b, 6c are provided on the discharge passage 8 side of each pump cylinder 2, and one of the outlet sides is connected to supply to the mixer 1, and the other is connected to the return flow passages 7a, 7b, 7c. To the respective liquid containers 4a, 4b, 4c. Each switching valve 6a, 6b, 6c is operated by a signal from the control device 14, and the supply of each liquid is controlled based on a sequence program set and inputted in advance. The mixer 1 forms a container that receives the supply of each liquid, and is equipped with a stirrer 15 for mixing and stirring.

With the above configuration, the liquid sucked up by the auxiliary pump 5 from each liquid container 4 is supplied to each pump cylinder 2a, 2b, 2c of the cylinder pump 2 through the switching valve 6. At the stage where each liquid is sucked into each pump cylinder, the switching valve 6 shuts off the auxiliary pump 5 side, and each liquid sucked by moving the piston moves from the discharge port of each pump cylinder to the switching valves 6a, 6b, 6c. To be supplied.

At this time, the pump cylinders are simultaneously moved by a common drive source to discharge the same amount. However, the switching valve 6 provided in each discharge passage 8 is the first that the main switching valve 6a is the mixer. The switching valve 6b, 6c of the other passage is opened to the return flow passage 7b, 7c side. Accordingly, only the main agent is supplied to the mixer 1, and when the required amount is supplied, the switching valve 6a operates, and the main agent is returned to the liquid container 4a via the return flow passage 7a. At the same time, the switching valve 6b provided in the discharge passage 8b of the hardener is opened to the mixer 1 side, and only the hardener is supplied to the mixer 1 this time. When the supply amount of the curing agent reaches a predetermined amount, the switching valve 6b is actuated again and returned to the liquid container 4b through the return flow passage 7b. Similarly, the next solvent is supplied to the required amount mixer 1 and pumped. When one discharge process of the cylinder is completed, the process proceeds to the suction process by each auxiliary pump again. Such supply of each liquid is shown in a sequence as shown in FIG.

That is, in the discharge process of the cylinder pump, the liquid amount supplied from the pump cylinder of each liquid to the mixer is supplied to the mixer 1 by a necessary amount according to the mixing ratio, and other discharge liquids are supplied to the liquid container 4 side. I try to return it. These timings are controlled by a switching signal from a control device that sets the movement amount of the piston in accordance with the mixing ratio and is linked to the movement of the servo motor by the pulse signal. For this reason, even if the mixture ratio fluctuates, it is possible to cope with any mixture ratio by simply changing the timing of each switching valve 6.

In FIG. 1, since the pump cylinder is used only for mixing each liquid, the switching valve operation of each liquid is distributed and discharged sequentially in one cylinder discharge process. Is not necessarily required to be switched in order, and may be programmed to return to the liquid container side when the respective supply amounts are reached after the supply to the mixer at the same time.

The configuration shown in FIG. 4 shows an embodiment in which a multi-liquid paint supply pump cylinder 20 is added to the spray gun in addition to the configuration of FIG. Therefore, four pump cylinders are provided and driven simultaneously. A switching valve 60 is provided on the discharge side of the pump cylinder 20 for the mixed liquid. The switching is connected to the return passage 70 so that one is returned to the spray gun 10 and the other is returned to the mixer 1 side. The side is connected to a supply pump 50 that feeds out the multi-component paint mixed in the mixer 1.

Therefore, spray coating by quantitative supply is possible in the discharge process of the multi-liquid paint supply pump cylinder. However, in this case, since the suction process on the cylinder pump side alternately enters, it is necessary to establish a sequence by associating with the discharge process by the cycle time of painting. The suction process of the cylinder pump needs to be performed during the waiting time in spray coating. Furthermore, it is necessary to detect the amount of the paint stored in the mixer as necessary, and to avoid inflow more than necessary. Various devices have been proposed for such liquid level detection, but the device is not particularly limited, and an applicable device may be selected under the conditions.

Here, the liquid mixture pump cylinder 20 supplied to the spray gun 10 does not necessarily have to be simultaneously operated by the same drive source, and may be configured to be driven and controlled in accordance with the operation of the spray gun. Especially when the quality of the coating is questioned, it is necessary to control the operation to perform accurate spraying in synchronization with spraying of the spray gun, or to supply paint to multiple spray guns from a mixer. It is also necessary to select according to the coating conditions.

In the case of the present invention, a predetermined amount of liquid is supplied from each pump cylinder to the mixer and used in the mixer with stirring. It is necessary to use it repeatedly. Therefore, it can be said that it is suitable for a paint that can obtain a relatively long pot life.

1 Mixer 2 Cylinder pump
2a, 2b, 2c Pump cylinder 3, 3a, 3b, 3c Control valve 4, 4a, 4b, 4c Liquid container 5, 5a, 5b, 5c Auxiliary pump 6, 6a, 6b, 6c Switching valve 7, 7a, 7b, 7c Return passage 8, 8a, 8b, 8c Discharge passage
11 Servo motor
12 Ball screw
13 Mobile
14 Control unit
15 Stirrer
24 Entrance passage
25 cylinders
26 Piston
28 Discharge port

Claims (4)

A plurality of cylinder pumps that are driven by a servo motor and deliver a fixed amount according to the number of pulses are connected and driven simultaneously, and the liquid supplied from the supply liquid container is discharged into each cylinder in the discharge process. And the other passage of the switching valve is returned to the supply liquid container of each cylinder according to the discharge amount required for each liquid in the discharge process. Multi-component paint that controls the switching valve so that it discharges to the mixer side during the number of pulses and returns to the supply liquid container during the other periods, and after each liquid is supplied to the mixer, it is mixed and stirred by the stirring means Mixing method. In a multi-component paint mixing apparatus comprising a cylinder pump, a supply means to the cylinder pump and a discharge liquid from the cylinder pump, and a mixer having a mixing means, the cylinder pump pulses the liquid supplied into the cylinder. A large number of pump cylinders that actuate pistons by a servo motor whose required amount is driven by a signal and perform constant discharge are arranged, and each is driven by the same servo motor at the same time. A valve is connected, one outlet of the switching valve is connected to the mixer, and the other outlet is connected to a liquid container of a supply means for supplying each liquid to each pump cylinder. Control that controls the time to supply each liquid discharged from the mixer to the mixer and the time to return to the liquid container based on a preset program Multi-liquid paint mixing device formed by providing a location. Each pump cylinder of the cylinder pump is provided with a control valve that communicates with the pump cylinder when each liquid from the supply means flows in, and that shuts off during discharge operation and returns the discharge liquid from the supply means to the liquid container. Item 2. The multi-component paint mixing device according to item 2. 3. The multi-component paint mixing apparatus according to claim 2, wherein the mixer comprises a liquid container for receiving each liquid and a mechanical stirrer.

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