JPH0263576A - Coating material supplying mechanism - Google Patents

Abstract

PURPOSE:To assure the fixed rate of a coating material to be discharged by operating a pressure regulating chamber so as to obtain a set discharge quantity when a discharge quantity set signal is outputted. CONSTITUTION:The air of the pressure corresponding to the set discharge quantity is supplied from an electropneumatic converter 23 to the pressure regulating chamber 18 in accordance with the pressure regulating signal outputted simultaneously with the discharge quantity set signal to increase the discharge quantity of a fixed delivery pump 5 and tube pipings 8, 11 instantaneously attain the expanded state corresponding to an increase in the discharge quantity when the above-mentioned discharge quantity set signal is outputted from a controller 16. The coating material in a tube piping 8 flows into the pressure regulating chamber 18 and the air of the pressure corresponding to the set discharge quantity is supplied from the electropneumatic converter 23 to the pressure regulating chamber 18 so that the tube pipings 8, 11 instantaneously attain the shrinkage state corresponding to the decrease in the discharge quantity when the signal to decrease the discharge quantity is emitted. The coating material of the required volume is, therefore, immediately discharged from a coater 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a coating agent supply mechanism for supplying coating agents such as paints of various colors and a main ingredient or curing agent of a two-component hot-mixing paint to a coating machine.

[Conventional technology]

Conventionally, in a general coating material supply mechanism, the coating material is pumped from a coating material supply source through a coating material feed pipe line by a circulation pump, and is transferred from a flexible tube piping from a coating material supply pipe that is branched to the feed pipe line. Coating agent is supplied to the applicator through the applicator and not discharged from the applicator is returned to the applicator supply source through the applicator return pipe (
(Refer to Utility Model Application Publication No. 57-8297.3).

Then, the pressure of the coating agent supplied from the coating agent supply source to the coating machine is adjusted by a regulator (pressure adjustment valve) installed in the coating agent supply piping, and the discharge amount of the coating machine is appropriately controlled. ing.

However, the viscosity of coating agents varies depending on the type of coating agent and the type and amount of solvent contained in it, and the viscosity of the same coating agent also changes depending on the temperature difference between morning and evening, so it is not possible to simply adjust the pressure of coating agent using a regulator. There was a problem in that it was not possible to delicately control the discharge amount of the coating agent.

For this reason, in automotive painting, which requires high-quality paint films, a regulator and metering pump are installed in the coating agent supply piping, and the rotation of the metering pump is controlled by an inverter to precisely control the amount of coating agent discharged. A control method has been adopted (see Japanese Utility Model Application Publication No. 58-58869).

[Problem to be solved by the invention]

However, metering pumps that are designed to delicately control the amount of coating material that can be delivered are very small, so it takes a long time to start dispensing the coating material until the amount reaches the required value. The drawback was that it took time to increase the amount to the required value.

In other words, immediately after increasing the rotational speed of the metering pump to a predetermined value and starting dispensing the coating agent from the applicator, or immediately after increasing the amount of dispensing agent, the metering pump is connected between the metering pump and the applicator. For 5 to 6 seconds until the tubing reaches an expanded state corresponding to the pressure of the coating agent sent by the metering pump, the discharge amount of the coating agent will be lower than the required value, and during this period, only the area where the coating agent was applied will be damaged. A problem arises in that the coating film becomes thinner than in the area. In addition, in the case of a two-component hot-mix paint, there is a problem that the mixing ratio of the base agent and curing agent changes, resulting in poor coating film quality.

In addition, immediately after the rotation speed of the metering pump is lowered to a predetermined value to reduce the discharge amount of the coating agent, the discharge amount of the coating agent may exceed the required value only while the tube is contracted due to the pressure drop of the coating agent. becomes.

In other words, when you start dispensing the coating agent or change the dispensing amount, the tube connected between the metering pump and the applicator expands or contracts, and the volume inside the pipe changes temporarily. Therefore, during this period, it was not possible to ensure quantitative properties of the coating agent discharged from the coating machine.

Therefore, the present invention aims to quickly (reach) the dispensing amount of the dispensing agent to the required value immediately after driving the metering pump at a predetermined rotational speed to start dispensing the dispensing agent, or immediately after increasing or decreasing the rotational speed of the metering pump. The objective is to solve this problem and improve the quality of the coating film.

[Means to solve the problem]

In order to achieve this object, the present invention provides a coating agent that supplies a coating agent sent from a coating agent supply source by a metering pump to a coating machine through a tube piping connected to a coating agent supply piping that interposes the pump. In the supply mechanism, a pressure adjustment chamber that instantaneously adjusts or reduces the internal pressure of the tube is connected to the tube, and the metering pump is driven at a predetermined rotation speed to discharge a required amount of coating agent from the coating machine. The present invention is characterized in that a control device is provided that outputs a pressure adjustment signal that operates the pressure adjustment chamber so that the set discharge amount is obtained when the discharge amount setting signal for setting the discharge amount is output.

[Effect]

According to the present invention, when a discharge amount setting signal that drives the metering pump at a predetermined rotational speed and discharges a required amount of coating agent from the applicator is output, a pressure adjustment signal that causes the control device to operate the pressure adjustment chamber is output. is output, and due to the function of the pressure adjustment chamber, the inside of the tube is momentarily pressurized when the dispensing agent starts or when the dispensing amount is increased, and when the dispensing amount of the dispensing agent is decreased, The pressure inside the tube is instantly reduced, and the discharge amount set to the required value is immediately obtained.

〔Example〕

Embodiments of the present invention will be specifically described below based on the drawings.

FIG. 1 is a flow sheet showing an example of a coating agent supply mechanism according to the present invention, and FIG. 2 is a time chart showing its operation.

In the coating agent supply mechanism shown in this example, coating agent is pumped from a coating agent supply source (1) through a coating agent feed pipe line (3) in which a circulation pump (2) is interposed, and a regulator (4) and a metering agent. A coating agent supply pipe (6) with a pump (5) interposed therein, a tube pipe (8) connected between the pipe (6) and the color change valve (7), and a color change valve (7). The coating machine (qo) is supplied through a tube pipe (11) connected between the manifold (9) to be attached and the coating machine (10).

In addition, the color change valve (7) is connected to a coating agent supply source (
A tube pipe 03) returning to 1) is connected.

The coating agent feed pipe (3) has a regulator downstream of the part to which the coating agent supply pipe (6) is connected, which maintains the pressure of the coating agent pumped by the circulation pump (2) at a constant high pressure. 0/8 is interposed.

Regulator (4) installed in coating agent supply pipe (6)
is adapted to reduce the pressure of the coating agent sent from the coating agent feed pipe line (3) to the metering pump (5) to a constant value.

The metering pump (5) is a gear pump in which the rotational speed of its motor q9 is variably controlled by an inverter (+7) based on a discharge amount setting signal output from a control device (10).

The tube piping (8) connected to the coating agent supply piping (6) that interposes this metering pump (5) has a pressure adjustment chamber (18) that instantly adjusts the internal pressure of the piping (8). ) are connected via a branch pipe 09.

A branch pipe 09) connecting the tube pipe (8) and the pressure adjustment chamber (18) is provided with a valve (PV, ) in the middle thereof for communicating and cutting off the pipe line.

In addition, between the coating agent supply pipe (6) and the branch pipe θ9), a pressure adjustment chamber θ9 is provided which branches from the coating agent supply pipe (6) between the metering pump (5) and the regulator (4). A bypass pipe O connected to the branch pipe (19) is connected between the valve (pv+) and the bypass pipe C.
! A drain pipe (21) for discharging the coating agent is connected to the connecting portion between [D and the branch pipe 09].

The bypass piping ce and the liquid drain piping (21) are equipped with valves (pvz) and (PV3) that cut off communication between the pipes, respectively.
is interposed.

The pressure regulating chamber (10) uses a diaphragm pump that is operated by a fluid pressure difference acting on both sides of the diaphragm (22), with the pressure of the coating material acting on one side of the diaphragm (22) and the pressure on the other side. is an electropneumatic converter (
23) through an air pipe (24) with an air vent valve (SQL) interposed therein.

Then, the control device Q6) drives the motor 05) of the metering pump (5) at a predetermined rotation speed when starting to discharge the coating agent from the coating machine GO) or when changing the discharge amount of the coating agent. At the same time, the pressure adjustment chamber (
18) The pressure adjustment signal that activates each valve (SQL)
', (PVI), (PVz), (PV3) and the electro-pneumatic converter (23).

That is, by switching the color change valve (7), the tube piping (8) and (11) are communicated with each other, and the coating machine (10)
When starting the dispensing of the coating agent or changing the dispensing amount, the control device (10
) outputs a discharge amount setting signal to the inverter 0'r) to drive the metering pump (5) at a predetermined rotation speed.

At the same time, the control device 0ω sends a pressure adjustment signal to the electropneumatic converter (23) and the pressure adjustment chamber (1).
A signal that temporarily connects the air pipe (24) connected between the valve (8) and the branch pipe 09 connected between the pressure adjustment chamber (18) and the metering pump θ8) is transmitted to A signal is output to the electro-pneumatic converter (23) and the valve (pv,), and a signal that temporarily supplies air to the pressure adjustment chamber 08) at a pressure corresponding to the set discharge amount of the coating agent. ) is output for.

In addition, from the electro-pneumatic converter (23) to the pressure adjustment chamber Q8)
The pressure of the air supplied to the tube is controlled based on a pressure detection signal from a pressure sensor (25) that detects the internal pressure of the tube (8).

Therefore, at the start of dispensing the coating material (T1 in Figure 2), the air piping (
Under the pressure of air supplied to the pressure regulating chamber (18) through the tube piping (8) and (11)
The internal pressure of the pipes (8) and (11) increases instantly.
reaches an expanded state according to the set discharge amount of the coating agent.

Therefore, a predetermined amount of the coating agent is discharged from the coating machine (10) at the same time as the coating agent starts to be discharged.

As soon as a predetermined amount of the coating agent starts to be discharged, the valves (SOL) and (PVI) are switched as shown in Fig. 1, and at the same time, the valve (PVz) is operated and the bypass pipe C! 0 is temporarily brought into communication with the pressure regulating chamber (
The pressure of the coating material acting on one side of the diaphragm (22) forming part 18) is returned to the original pressure that is constantly controlled by the regulator (4), and the pressure regulating chamber Q8) can cope with the increase in the discharge amount. Wait in state.

In this state, when the control device 0ω outputs a discharge amount setting signal that increases the rotation speed of the metering pump (5) to increase the discharge amount (T, in Figure 2), the pressure adjustment signal is output at the same time as the signal. Based on the signal, air at a predetermined pressure according to the set discharge amount is supplied from the electro-pneumatic converter (23) to the pressure adjustment chamber (10), and the tubes (8) and (11) instantly discharge the coating agent. An expanded state corresponding to the increase in amount is reached, and the coating agent aω immediately discharges the coating agent increased to the required amount.

After the discharge amount is increased, the pressure adjustment chamber θ
The pressure of the coating agent acting on one side of the diaphragm (22) in step 8) is returned to the original constant pressure, and the system waits in a state that can cope with the next increase in the discharge amount.

In this state, when a discharge rate setting signal is output that increases the rotation speed of the metering pump (5) to further increase the discharge rate (
T3) in Figure 2), an electro-pneumatic converter (23) based on the pressure adjustment signal
) is supplied to the pressure adjustment chamber side at a predetermined pressure according to the set discharge amount, and the tube piping (8) and (It
) instantaneously reaches an expanded state corresponding to the increase in the amount of coating agent discharged, and the coating agent (10) immediately discharges the required amount of coating agent.

After the discharge amount is increased, the valves (SQL) and (PV+) are switched as shown in Fig. 1, and at the same time,
The valve (PV3) is operated and the liquid draining pipe (21) is temporarily brought into communication, and the branch pipe Q9) is connected from the pipe (21) between the pressure adjustment chamber 0 powder and the valve (pv+). A pressure adjustment chamber (18) is provided so that the coating agent inside is extracted and depressurized to cope with the reduction in the discharge amount.
Wait with the pressure acting on one side of the diaphragm (22) set to zero.

In this state, when the control device (16) outputs a discharge amount setting signal that lowers the rotation speed of the metering pump (5) to reduce the discharge amount (T4 in Fig. 2), the signal is output at the same time. Based on the pressure adjustment signal, the 4) rev (PVl) is opened and the coating agent in the tube piping (8) is transferred to the branch piping 0.
9) into the pressure adjustment chamber a0, and air at a predetermined pressure corresponding to the set discharge amount is supplied from the electro-pneumatic converter (23) to the pressure adjustment chamber (18), and the tube piping (8) and θ0 are A contracted state corresponding to the decrease in the amount of coating agent discharged is instantaneously reached, and the coating agent reduced to the required amount is immediately discharged from the coating machine θ0).

Thereafter, when a discharge amount setting signal that further reduces the discharge amount is output (T in Fig. 2), the above-mentioned operation is repeated to immediately discharge the coating agent reduced to the required amount from the applicator (10). be able to.

By doing the above, when the applicator (10) starts discharging the coating agent or increases the dispensing amount, the internal pressure of the tube piping (8) and 01) can be instantly increased to the required value, and When the discharge amount is decreased, the pressure inside the pipe is instantly lowered to the required value, and the predetermined discharge amount can be obtained immediately. (See the discharge amount of the present invention shown by the solid line).

Therefore, for example, in color change painting, after the previous color paint is finished and color change cleaning is performed, the next color paint can be applied immediately, and the tube piping (
Since there is no need to wait until the internal pressures of pipes 8) and (11) are increased by the metering pump (5), the color change time can be significantly shortened.

In addition, even during painting, the amount of paint discharged can be instantly increased or decreased in response to changes in the shape and size of the object to be painted, and the paint film will not become partially thin or thick. The quality of the coating is significantly improved.

Furthermore, when applying a two-component hot-forming paint, it is possible to always maintain a constant mixing ratio of the main agent and curing agent supplied to the coating machine, thereby preventing the occurrence of paint film defects.

In particular, before increasing or decreasing the discharge amount of the coating material, check the valve (pv
If the pressure in the branch pipe θ9) connected between +) and the pressure adjustment chamber (18) is adjusted to a predetermined pressure in accordance with the increase or decrease in the discharge amount, the predetermined discharge amount can be reached more quickly. can get.

Note that the pressure adjustment chamber (18) is not limited to a diaphragm pump, and may be a cylinder, a balloon, or the like, and in short, any configuration that can instantly adjust the internal pressure of the tube piping (8) and (11) is sufficient. .

Moreover, the pressure adjustment chamber 02 may be one in which a balloon having an inlet and an outlet formed at both ends is directly interposed in the conduit of the tube piping (8).

Further, the coating agent from the coating agent supply source (1) is supplied to the circulation pump (2).
) may be used to supply the coating machine qω only by the metering pump (5).

〔Effect of the invention〕

As described above, according to the present invention, when the metering pump is driven at a predetermined rotational speed to start discharging the coating agent from the applicator, or while the coating agent is being discharged, the rotational speed of the metering pump is increased or decreased. In some cases, the amount of coating agent discharged quickly reaches the required value determined by the rotation speed of the metering pump, which prevents insufficient coating at the start of painting and improves coating quality. It can significantly shorten the color change time, and even during painting, when increasing or decreasing the amount of coating material dispensed according to changes in the shape and size of the object to be coated, it is possible to avoid insufficient coating or excessive coating. This has a very excellent effect in that it can prevent the occurrence of paint film defects caused by the mixing ratio of the main component and curing agent of the two-component hot-forming paint being disrupted.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet showing an example of a coating agent supply mechanism according to the present invention, and FIG. 2 is a time chart showing its operation. Explanation of symbols (1) - Coating agent supply source, (5) Fixed amount pump, (
6) - Coating agent supply piping, (8) --- Tube piping, θ
0)...Coating machine, θω motor, (16)--Control device, 0'r)--Inverter, θ8) Pressure adjustment chamber.

Claims (1)

[Claims] The coating agent sent from the coating agent supply source (1) by the metering pump (5) is transferred to the coating agent supply piping (in which the pump (5) is interposed).
The applicator (
10), a pressure adjustment chamber (18) is connected to the tube (8) to instantly adjust the internal pressure thereof, and the metering pump (5) is controlled to a predetermined level. The coating machine (10
) A control device (16) that outputs a pressure adjustment signal that operates the pressure adjustment chamber (18) so that the set discharge amount is obtained when a discharge amount setting signal that causes the required amount of coating agent to be discharged is output from the controller (16). A coating agent supply mechanism characterized by being provided with.