JP5102093B2 - Supply amount setting method of two-component paint supply device - Google Patents

Description

The present invention relates to a method of supplying respective liquids to a premixing apparatus that alternately supplies two liquids in advance and uniformly disperses them when a multi-component paint is uniformly stirred and mixed in a mixer.

In the field of spray coating, two-component polyurethane coating and two-component epoxy coating form a coating film by reaction curing by mixing and spraying a curing agent, which is a catalyst, with the main component having a small solvent component. Has been used for a long time because of its excellent coating properties such as weather resistance, chemical resistance and water resistance.

In response to environmental pollution problems in recent years, organic solvents can be eliminated during coating film formation, drying furnaces can be eliminated and the temperature can be reduced, and effective use is expected as an effective coating method for energy saving. ing.

However, in a two-part or multi-part paint such as a two-part polyurethane paint or a two-part epoxy paint, when mixing the curing agent with the main agent, it is necessary to mix accurately and uniformly at the mixing ratio set by the paint. If this mixing condition varies, not only the formed coating film will not exhibit sufficient performance, but also a partial coating performance spot will occur, resulting in poor coating quality and durability. Will cause. Therefore, in painting, a supply device that feeds the paint supplied to the coating machine in an accurately and uniformly mixed state plays an important role.

Various methods have been proposed to accurately supply at a stable mixing ratio. The liquids are alternately supplied in the required amount, mixed and mixed in the premixer, and sufficiently stirred and mixed in the main mixer. After that, the method of supplying to the coating machine is easy to control the flow rate of each liquid corresponding to various mixing ratios, and when each liquid is supplied at the same time, depending on the conditions, one of the liquids flows backward and curing due to the reaction occurs. However, there is a problem that the passage is clogged, and the advantage is that stable mixing is possible.

Examples of such an apparatus can be found in Japanese Patent Application Laid-Open No. 11-347393. In this case, the premixer is made the minimum size to minimize the amount of paint that is wasted when changing or washing the paint, but the ratio of the two liquids to be mixed varies depending on the paint used. When the value is large, the amount of one liquid supplied per time decreases, and it becomes difficult to accurately control the flow rate. Therefore, the total of both liquids becomes the minimum necessary when the smaller amount at the maximum mixing ratio can be controlled.

On the other hand, the supply amount per time supplied to the premixer, that is, the total supply amount of the liquid a (generally the main agent) and the liquid b (generally the curing agent) can be accommodated in the premixer. Must be. If it is increased, it is sent to the main mixer in a state where one of the liquids that cannot be accommodated is insufficient, so that uniform mixing cannot be performed.

Furthermore, in the method of controlling the supply of each liquid, the actual flow rate is detected by a flow meter, the correction amount with the set value is fed back to the control device, and the supply amount of the other liquid is changed. If it is larger, the correction amount also increases in proportion to the ratio. For example, in the case of 20: 1, it is necessary to supply 20 times as large as the amount of fluctuation caused by the smaller one as the correction amount. This tendency becomes stronger from the responsiveness of the valve as the overall paint flow rate increases.
JP 11-347393 A

When the capacity of the premixer is set, if there is an error in the actual flow rate just by allocating the supply amount of each liquid according to the mixing ratio, supplying the correction amount corresponding to the error will cause an excess supply amount May not fit. In particular, when the mixing ratio is increased, the possibility is high, and the mixing becomes uneven, resulting in variations in coating quality.

In a multi-component paint supply device that uniformly mixes a multi-component paint in which the curing agent is dispersed in the main agent by a pre-mix device at a predetermined ratio in a main mixer and supplies it to the coating device, the pre-mix device and the main agent are cured When alternately supplying each liquid of the agent, an amount obtained by subtracting an amount proportional to the mixing chamber volume of the premix according to the mixing ratio of the main agent with respect to the curing agent from the mixing chamber volume is 1 cycle. A supply amount of the main agent and the curing agent is used, and an amount distributed according to a mixing ratio of the main agent and the curing agent is supplied as each supply amount.

According to the above, the total amount of the main agent to be supplied and the curing agent is always set smaller than the mixing chamber volume of the premix, and the set amount becomes smaller as the mixing ratio becomes higher. There will be more room to spare. Therefore, even if the correction supply amount is increased at the same magnification as the mixing ratio with respect to the fluctuation amount, it is possible to reliably store and distribute each liquid evenly as set.

Since the supply amount of the main agent and the curing agent per one time is set according to the mixing ratio, an appropriate value is always set within a range where there is no problem, so the mixing ratio of the paint to be used is not considered each time. Is automatically derived from and incorporated into the controller to allow optimal mixing.

FIG. 1 is a block diagram showing the construction of a multi-component paint supply apparatus including a mixing apparatus for carrying out the present invention. The liquid a serving as the main agent is sent from the supply device 1a to the premixer 4 through the flow meter 2a and the on-off valve 3a. On the other hand, the liquid b serving as a curing agent is sent from the supply device 1b to the premixer 4 through the flow meter 2b and the on-off valve 3b. The main agent and the curing agent are sent to the static mixer 5 as a mixed liquid premixed in the premixer 4, where the mixture is sufficiently agitated and mixed through the paint pressure reducing valve 6 and the like, and the discharge on / off valve of the spray gun 7 and the like. It is discharged via.

The premixer 4 is provided with a controller 8 as a means for supplying and controlling the flow rate of the main agent and the curing agent at a preset mixing ratio, and is associated with the detection signal of the flow meter and the control signal of the on-off valve, Control such as alternately supplying the main agent and the curing agent is performed based on a program input or stored in advance.

The premixer 4 forms a mixing chamber 14 having a predetermined internal volume. After the main agent flows in from one inlet 9 and the curing agent is mixed in the mixing chamber, the other outlet 11 enters the static mixer 5. It is sent. Inside the mixing chamber, there is provided a jet 10 for dispersing the curing agent in the main agent. The main agent and the curing agent are alternately fed into the mixing chamber 14 from the supply device, and one cycle is completed with one supply.

The volume in the mixing chamber 14 is normally about 30 ml to 50 ml, and is made as small as possible for the reasons described above. The mixing ratio of the multi-component paint to be used varies, and usually 1: 1 to 20: 1 is a range that is often used. Therefore, if the capacity is 50 ml, it is sufficient to control the supply of 25 ml each in the case of 1: 1, but in the case of 20: 1, the supply amount of the curing agent must be controlled to 2.38 ml with respect to 47.6 ml of the main agent. If it is necessary to apply even in the case of a higher mixing ratio, the control of the supply amount is required to be more strict, or the capacity of the mixing chamber will be expanded.

Although the supply amount is controlled by an on-off valve, the actual flow rate varies depending on the valve operation, flow resistance of the pipeline, etc. In general, the actual flow rate detected by the flow meter is fed back and corrected in the next cycle. The method to do is taken. For this reason, the amount of the main agent and the curing agent added is set to be smaller than the mixing chamber capacity as an initial set value so that it can be accommodated in the mixing chamber including the supply amount when increased by correction.

FIG. 2 shows a graph showing the relationship between the main agent and the curing agent supply amount set according to the mixing ratio when the volume is 50 ml in the practice of the present invention. The solid line indicates the total amount (depending on the mixing ratio). The corrected capacity) and the dotted line indicate the supply amount of the curing agent.

The total supply amount is a value obtained by subtracting the mixing ratio from 50 ml. In the case of 20: 1, 50-20 = 30 (ml). The supply amount of the curing agent is about 1.43 ml by dividing 30 ml by a ratio of 20 and 1. In practice, the higher the mixing ratio, the more difficult it is to control the supply amount, and there is a possibility that the rate of error from the actual flow rate will increase. Further, the supply amount of the main agent to be corrected next with respect to the error corresponds to 20 times as much as 20: 1, and is set to a supply amount that leaves a margin.

As a result, the dispersion state of the main agent and the curing agent in the premixer was confirmed at several mixing ratios. As a result, a stable dispersion state was produced without overflowing from the container, and reliable mixing was possible. Based on the above criteria, it is possible to enable proper supply by multiplying the mixing ratio subtracted by the balance between the capacity of the mixer and the maximum mixing ratio by a coefficient. In the above embodiment, the coefficient is 1 because the volume is 50 ml and the maximum mixing magnification is 20.

For example, if the supply accuracy is improved and the volume of the mixer can be reduced, if the supply ratio is extremely reduced by subtracting the mixing ratio from the capacity as it is, the value multiplied by a constant of 1 or less should be subtracted. It is sufficient to set a certain lower limit value so that it does not fall below that. In addition, when the control of the coating with a large discharge amount cannot catch up, the mixer itself can be handled with a large capacity by subtracting one or more coefficients. Usually, the amount of supply in one cycle can be adjusted to 2/3 to 1/3 of the mixer capacity, so that various mixing ratios can be accommodated.

Therefore, according to this method, it is possible to easily set an appropriate supply amount regardless of the mixing ratio, and to remove the burden and troublesomeness of the operator. Moreover, if it is used as a control program, stable supply control can always be achieved. In the embodiment, the volume (ml) is basically described, but the same applies even if the mass (g) is replaced.

1 is an overall configuration block diagram of a paint supply apparatus including a mixing apparatus to which the present invention is applied. The graph which shows the setting value of the supply amount set by this invention.

Explanation of symbols

1a, 1b, supply devices 2a, 2b, flow meters 3a, 3b, on-off valve 4, premixer
5. Static mixer 9, main agent inlet
10, injection port
11. Outlet of mixed liquid

Claims (1)

In a multi-liquid coating material supply apparatus that uniformly mixes a multi-liquid paint in which a curing agent is dispersed in a main agent by a pre-mix device in a predetermined ratio in advance with a main mixer and supplies it to a coating apparatus, When alternately supplying each liquid of the curing agent, the amount obtained by subtracting the amount proportional to the mixing ratio from the mixing chamber volume is subtracted from the mixing chamber volume of the premix according to the mixing ratio of the main agent to the curing agent. A method for setting the supply amount of a two-component paint supply device in which the supply amount of the main agent and the curing agent per cycle is set to the supply amount according to the mixing ratio of the main agent and the curing agent.

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