WO2008001451A1

WO2008001451A1 - Paint supply system

Info

Publication number: WO2008001451A1
Application number: PCT/JP2006/313021
Authority: WO
Inventors: Shinji Katayama
Original assignee: Durr Japan K.K.
Priority date: 2006-06-27
Filing date: 2006-06-29
Publication date: 2008-01-03
Also published as: JP2009213945A

Abstract

A paint supply system where pulsation is prevented with the instantaneous flow rate of paint secured and where settling of the paint is prevented. The paint supply system (10) has a paint flow path (3), painting machines (21, 22), a pump (6), and a buffer device (7). The paint is supplied from a tank (5) to the paint flow path (3), and the paint in the paint flow path (3) can return to the tank (5). The paint is supplied to the painting machines (21, 22) via a branch path (40) connected to the paint path (3). The pump (6) draws the paint from the tank (5) and sends it out. The buffer device (7) receives a specific amount of the paint sent from the pump (6) and sends out the received paint under a specific pressure to the paint path (3).

Description

Specification

Paint supply system

Technical field

The present invention relates to a paint supply system. In particular, the present invention relates to a paint supply system that supplies paint to a plurality of coating machines arranged in a paint line and collects surplus paint.

Background art

[0002] For example, a paint supply system for painting a car body of an automobile is provided on both sides and the upper part of a painting booth in order to apply undercoat, intermediate coat, and topcoat to various parts such as a roof part and a side part of the car body. A number of painting machines such as painting guns are arranged along the painting line. The paint supply system connects the paint tank and each painter with a pair of paint supply pipes, supplies the paint in the paint tank by a pressure feed pump, and supplies the excess paint from each painter to a pair of paint return pipes. Is collected in the paint tank.

[0003] Since the paint supply system as described above changes the paint color depending on the vehicle type, etc., the same number of paint piping lines as the number of paint colors are provided, and color change valves (hereinafter referred to as CCV) connected to each paint machine. Therefore, the paint piping line is selectively switched with respect to the coating machine. However, since the conventional paint supply system has a pair of paint supply pipes and a pair of paint return pipes on both sides of the paint booth, the pipe length is very long and the paint volume in all the pipes is large. Yes. Therefore, a large amount of paint must be discarded at the time of color change, paint loss increases, the loss of thinner used for cleaning also increases, and the time required for color change becomes long and the efficiency becomes poor.

[0004] Therefore, in a paint supply system that supplies paint to a plurality of coating machines provided on both sides of the paint line and collects surplus paint !, all paint supply piping and paint return piping A coating supply system has been invented that shortens the length and reduces the loss of paint during color change and the loss of cleaning thinner (see, for example, Patent Document 1).

Patent Document 1: JP-A-6-343914

Disclosure of the invention Problems to be solved by the invention

FIG. 4 is a piping diagram of a paint supply system according to Patent Document 1. FIG. 4 of the present application corresponds to FIG. In FIG. 4, a plurality of pairs of painting machines 86 and 86 are arranged at predetermined intervals on both sides of the painting booth 8 provided in the painting line. In addition, a plurality of coating machines 87 are appropriately arranged above the painting booth 8. For example, a pair of applicators 86 · 86 paints the sides of the car body, and a painter 87 paints the roof of the car body.

In FIG. 4, a paint supply pipe 80 is provided on one side of the painting booth 8 in the length direction of the painting line, and a paint return pipe 81 is provided on the other side of the painting booth 8. Is arranged. The downstream end of the paint supply pipe 80 is communicated with the upstream end of the paint return pipe 81 through the orifice 82 at the line end of the paint line. Further, the upstream end of the paint supply pipe 80 is connected to the pressure pump 84. The pressure pump 84 pumps the paint in the paint tank 83. Further, the downstream end of the paint return pipe 81 is connected to the paint tank 83 via the back pressure valve 85.

[0007] In FIG. 4, the painting booth 8 includes a plurality of paint supply pipes 80 and a plurality of paint return pipes 81 at positions where a pair of painters 86 and 86 or a painter 87 are provided. Binos piping 86a is installed. A pair of painters 86 · 86 or painter 87 is connected to these bypass pipes 86a. Then, paint is supplied from these bypass pipes 86a to the respective painting machines 86 and 87. A CCV87 is connected to each painter 86 · 87, and the CCV87 allows selection of multiple colors of paint piping lines.

[0008] In the paint supply system shown in Fig. 4, the paint flowing out from the paint tank 83 flows into the paint supply pipe 80 by the pressure feed pump 84, flows out into the paint return pipe 81 through the orifice 82, and a plurality of bypass pipes. The paint also flows from the paint supply pipe 80 to the paint return pipe 81 through 86a. Therefore, painting by each painting machine 86 · 87 becomes possible. Further, surplus paint that has not been used for painting is collected in the paint tank 83 from the paint return pipe 81. By such movement, the paint is circulated.

[0009] In FIG. 4, the piping line is simply provided with one paint supply pipe 80 on one side of the painting booth 8 and one paint return pipe 81 on the other side. It has a line configuration, and the total pipe length is greatly reduced compared to the conventional one. Therefore, paint in all pipes As the volume is significantly reduced, the loss of paint during color change when discarding paint that is no longer used and the loss of thinner used for cleaning are reduced, and the work time required for this color change is also shortened. The efficiency increases.

[0010] Further, since the total pipe length is shortened, the pressure loss force between the upstream end of the paint supply pipe 80 and the downstream end of the paint return pipe 81 is reduced, and the capacity of the pressure feed pump 84 needs to be increased. There is an advantage that the pipe diameter can be narrowed without any problems. In particular, reducing the pipe diameter has the advantage of reducing the piping space when bundling multicolored painted piping lines.

In FIG. 4, since the paint supply pipe 80 and the paint return pipe 81 communicate with each other through the orifice 82, the flow velocity of the paint flowing into the paint return pipe 81 can be reduced by the orifice 82. The pressure in the paint supply pipe 80 is kept higher than the pressure in the paint return pipe 81. In other words, if a pressure difference is created by the orifice 82 so that the minimum flow rate at which the metallic piece of paint does not precipitate in each pipe or higher flow rate is obtained, the pressure difference ensures that the paint is surely applied to each bypass pipe 86a. It can be applied without using a regulator as in the past. For this reason, there is no problem of deformation of the metallic pieces in the paint due to the use of the regulator, and a high-quality coating is applied.

[0012] The above-mentioned paint supply pipe 80 and paint return pipe 81 are called main lines, and the bypass pipe 86a and the pipe leading to the coating machine 86 · 87 via the CCV are called branch lines. It is.

[0013] In general, paints are roughly classified into water-based paints and oil-based paints. In industrial paint supply systems, the proportion of water-based paint used is increasing compared to oil-based paints that use organic solvents. Water-based paints have the disadvantage of a large pressure loss in piping lines, which generally have a higher viscosity than oil-based paints. However, water-based paints do not use organic solvents with high volatility like oil-based paints, so there is an advantage that the effect of solidification due to sedimentation in the piping line is low.

[0014] Taking advantage of this water-based paint, paint supply systems in which the main line circulates the paint and the branch line does not circulate the paint are terminated. However, this paint supply system discharges the paint in the branch line so that it does not solidify during long-term shutdown. It is necessary to keep it. Therefore, even for paint supply systems for water-based paints, the so-called two-pipe method, in which paint circulates in the main line and branch line, is the mainstream.

[0015] A paint supply system that can share water-based paint or oil-based paint, and in the branch line, in particular, a paint supply system having a swing function is required in order to make the oil-based paint uniform so as not to settle. And

[0016] In the industrial paint supply system shown in FIG. 4, electrostatic coating machines are often used as the coating machines. In particular, electrostatic coating machines equipped with a canister (pressure vessel) type voltage block function are widely used for electrostatic coating by direct application of water-based paint. The paint supply system requires a supply amount of 4-5 liters Zmin because the canister has a capacity of 200 cc to 700 cc and it is necessary to fill the canister with a short time when changing colors.

[0017] As described above, a paint supply system using a caster requires a paint supply amount about five times that of a general paint supply system, and considering the simultaneous operation of a plurality of electrostatic coating machines, The supply capacity of pumps and piping is very large. For example, the net paint usage per car body is 3-4 liters. The current supply capacity of force pumps and pipes is about 10 times the net paint usage.

[0018] There is a need for a paint supply system that has a paint supply capacity that is close to the net amount used, and that satisfies the instantaneous paint supply capacity of a electrostatic electrostatic coater using a caster method. .

Furthermore, in the paint supply system as shown in FIG. 4, a plunger pump is used as a pressure feed pump. Plunger pumps are disadvantageous in that they have many pulsations that are superior in preventing paint deterioration by circulating paint. There is an example in which a surge chamber is connected in series with a plunger pump to suppress pulsation, but the effect is limited.

[0020] A canister-type electrostatic coating machine using a painting robot is not affected by pulsation, but spray painting using a coating gun, so-called hand-painted painting, has a large influence of pulsation. The two-pipe paint supply system generally does not have a pressure adjustment valve on the paint gun, and the paint discharge rate at the beginning of spraying by the paint gun is large. I have a problem.

[0021] It may be possible to use an electric rotary pump in place of the plunger pump. The power is expensive, and the paint is deteriorated such that the metallic piece of the paint is pulverized and is not put to practical use. There is a need for a paint supply system that can prevent pulsation even if an inexpensive plunger pump or diaphragm pump is used as a pressure pump. The above is the subject of the present invention.

The present invention has been made in view of such problems, and provides a paint supply system that prevents pulsation while ensuring an instantaneous flow rate of paint, and prevents sedimentation of paint in a branch line. For the purpose.

Means for solving the problem

[0023] The present inventor has found that the pressure pot and the swinging big (Pig) can be used to prevent pulsation while securing the instantaneous flow rate of the paint, and to prevent the paint from settling in the branch line. Based on this, we have invented the following new paint supply system: o

[0024] (1) Tank force A paint flow path through which paint is supplied and paint can be returned to the tank, and a coating machine to which the paint is supplied through a branch path connected to the paint flow path are provided. A paint supply system, wherein the tank-powered paint is sucked and a fixed volume is accommodated in a pressure-feeding pump for sending the paint and the paint delivered from the pressure-feed pump, and the contained paint is stored in the paint flow path. And a shock absorber for pumping at a constant pressure.

[0025] The paint supply system according to the invention of (1) includes a paint flow path and a coating machine. It is also equipped with a pressure pump and a shock absorber. The paint channel is supplied with paint from the tank and can return to the tank. The coating machine is supplied with paint via a branch path connected to the paint flow path. The pressure pump sucks the paint from the tank and delivers the paint. The shock absorber stores a constant volume of paint sent from the pressure pump pump and pumps the stored paint to the paint flow path at a constant pressure.

[0026] Here, paint is stored in the tank! / The paint may be an aqueous paint or an oil paint and may be a mixed paint in which a pigment and a vehicle (liquid component) are mixed. Turn on the stirrer that stirs the mixed paint so that the pigment and vehicle do not separate or settle and thicken. It is preferable to provide the For example, the stirrer is operated by a hydraulic motor.

[0027] A pressure feed pump is provided between one end of the tank and the paint flow path, and the pressure feed pump is driven to supply the paint from the tank to the one end side of the paint flow path. The paint can be returned to the tank via the back pressure valve. In the paint flow path, the paint can be returned to the tank means that the surplus paint of the painting machine can be collected in the tank. The paint flow path is a closed circuit surrounding the paint line, and the paint is collected in the tank. It is also possible to circulate the paint through the paint flow path. Here, the paint channel is a so-called main line, and is a pipe as a substance.

[0028] The coating machine is an electrostatic coating machine having a painter robot voltage block function and a gear pump type spray coating machine using a coating robot. The paint is supplied through a branch path connected to the paint flow path, which is a so-called hand-painted coater. Here, the branch path is a so-called branch line, which is a tube as a substance. The branch path may be provided with a swaying device for swaying the paint in the branch path as will be described later.

[0029] As will be described later, it is preferable that the coating machines are arranged in parallel so as to face each other along both sides of the painting line. The electrostatic coating machine, the spray coating machine, and the painting gun described above are arranged in parallel. It is possible to appropriately configure a painting line that can be arranged with these coating machines.

[0030] The pressure feed pump includes a centrifugal pump such as a spiral pump that utilizes the liquid transfer principle by centrifugal force, and a volume rotary type based on the liquid transfer principle based on a rotary volume change such as a screw pump. These pumps may be included, and a volume reciprocating pump described later may be included. Centrifugal pumps have the difference that positive displacement pumps with pulsation from the discharge port have positive reciprocating pumps with small pulsation from the discharge port, and pulsation from the discharge port. When the pressure pump is driven, the tank force also sucks the paint and sends it out. And the coating material which also sent out the pressure pumping force is accommodated in the shock absorber.

[0031] As will be described later, the shock absorber is a container as a substance, and functions to accommodate a certain volume of paint to be delivered by a pressure pump force. A shock absorber containing a certain volume of paint means that the volume of the paint fluctuates. For the paint consumption of the coating machine, When the amount of paint supplied is large, the capacity of the paint increases, and when the amount of paint supplied by the pressure pump is small, the capacity of the paint decreases.

[0032] The shock absorber is set to have a maximum capacity so that the container does not become full of paint, and a minimum capacity is set so that the paint does not become empty in the container. The shock absorber controls the coating material in the container to vary between the maximum capacity. Here, the capacity of the pressure pump is set so that the amount of paint supplied per unit time of the pressure pump exceeds the amount of paint consumed per unit time of the coating machine!

[0033] By supplying the compressed fluid to the container, the shock absorber can pressurize the paint, which is an incompressible fluid, at a constant pressure regardless of the volume fluctuation of the paint in the container. Then, the paint contained in the container can be pumped to the paint flow path at a constant pressure. Pumping the paint contained in the container at a constant pressure to the paint flow path means that the paint is supplied to the paint flow path at a constant flow speed determined by the pipe diameter of the paint flow path and the pressure. ing.

[0034] Since the paint supply system according to the invention of (1) pumps the paint contained in the shock absorber to the paint flow path at a constant pressure, for example, the filling of the paint into the canister has a large capacity. Can be averaged because of the short time. In the conventional paint supply system, paint is immediately supplied from the pressure pump to the paint flow path, the so-called main line. Therefore, in order to secure an instantaneous amount of paint supply, the capacity of the pressure pump can be increased, It was necessary to increase the main line diameter. In the paint supply system according to the invention of (1), an instantaneous flow rate of the paint can be secured by interposing a shock absorber between the pressure feed pump and the main line. It can also be said that it can support existing facilities.

(2) It is interposed between the tank and the pressure pump, and can be switched between a direction in which the paint flows out from the tank to the pressure feed pump or a direction in which the paint returns from the paint flow path to the tank. A direction control valve is provided, and the shock absorber includes a container for storing a fixed volume of paint, a liquid level detector for detecting the volume of the paint stored in the container, and a maximum capacity of the paint stored in the container. (1) The paint supply system according to (1), further comprising: a control unit that receives the signal of the liquid level detector and switches the direction control valve so as to maintain a minimum capacity.

[0036] The paint supply system according to the invention of (2) includes a directional control valve. Also, the shock absorber is , A container, a liquid level detector, and control means. The direction control valve is interposed between the tank and the pressure pump. The directional control valve can be switched to the direction in which the paint flows out to the tank force pump, or the direction in which the paint returns to the paint flow force tank. The container contains a certain volume of paint. The liquid level detector detects the volume of paint contained in the container. The control means receives the signal of the liquid level detector and switches the direction control valve so that the paint contained in the container is maintained between the maximum capacity and the minimum capacity.

[0037] The directional control valve can suck the paint into the tank force pump by switching the directional control valve, which is a three-way valve, to the first direction. When the direction control valve is switched to the second direction, the flow path to the tank force pump is closed and the paint can be returned to the paint flow force tank. The direction control valve is a pilot operated directional control valve by hydraulic pressure or an explosion-proof electromagnetic valve, and the direction of paint flow is switched by a signal to a control unit described later.

[0038] The container is a cylindrical sealed container, preferably a pressure container. Paint flows in from the bottom of the container and compressed fluid is supplied from the top of the container. If the amount of paint supplied by the pressure pump is higher than the amount of paint consumed by the coating machine, the liquid level of the paint in the container will increase, and if the amount of paint supplied by the pressure pump is low1, the paint in the container will The liquid level decreases.

Here, the maximum volume and the minimum volume of the container are converted into the liquid level, and the maximum liquid level and the minimum liquid level are set in advance. It can also be said that it is converted into a high level and a low level. The paint discharge port is located between the low level and the bottom of the container. The liquid level detector converts the high level and low level detection values of the liquid level into electrical signals. As the liquid level detector, a magnetic float type liquid level meter, an ultrasonic level meter, a light reflection detector or the like is appropriately used.

[0040] The control means includes a control panel, which receives the detection signal of the liquid level detector and transmits a switching signal for switching the direction control valve. When a low level signal is sent to the control board, the control board switches the directional control valve to the first direction. The container is then filled with paint from the tank. When a high level signal is sent to the control board, the control board switches the direction control valve to the second direction. The paint channel can also return the paint to the tank.

[0041] The paint supply system according to the invention of (2) has the maximum capacity and the minimum capacity of the paint contained in the container. In order to maintain the capacity, a simple control is performed to switch the direction control valve by receiving the signal of the liquid level detector. Here, while the paint is being replenished to the container, the circulation of the paint in the paint flow path is stopped, but it is considered that the effect of the sedimentation of the paint is small.

[0042] (3) The paint supply system according to (2), wherein the shock absorber includes supply means for supplying a compressed fluid so that a space in the container maintains a constant pressure.

[0043] In the paint supply system according to the invention of (3), a pressure regulating valve and a direction switching valve are connected in series between a compressed fluid source and a container provided with a compressed fluid source for storing air or nitrogen gas. For example, a pressure gauge is provided in the container, and when the space in the container falls below a predetermined pressure, the direction switching valve is switched so that the compressed fluid can be supplied to the container. When the space in the container is within the predetermined pressure, close the direction switching valve. When the space in the container exceeds the predetermined pressure, the direction switching valve is switched so that the compressed fluid flows backward to the compressed fluid source side.

[0044] In the paint supply system according to the invention of (3), as described above, the shock absorber constitutes the supply means for supplying the compressed fluid, so that the space in the container can be maintained at a constant pressure with the compressed fluid. . Compressed fluid has the advantage of a fast response time to a constant pressure with respect to varying paint capacity.

[0045] (4) The paint supply system according to (3), wherein the compressed fluid is nitrogen gas.

[0046] By using nitrogen gas, which is an inert gas, as the compressed fluid, for example, oxidation of the paint can be prevented.

[0047] (5) The paint supply system according to any one of (1) to (4), wherein the pressure feed pump is a volume reciprocating pump.

[0048] The positive displacement pump may include a plunger pump or a diaphragm pump based on a liquid transfer principle based on a reciprocating volume change. These pumps are generally inexpensive and are suitable for practical use because the metallic pieces of paint are not crushed and the paint does not deteriorate.

[0049] In the paint supply system according to the invention of (5), the paint sent out by the pumping pump force is supplied to the paint flow path after being accommodated in the buffer device, that is, the paint flow is buffered. Therefore, the pulsation which generate | occur | produces with a pressure pump can be prevented. The shock absorber is a co It can also be said that it functions in the same way as a capacitor and constitutes a smoothing circuit. The paint supply system according to the invention of (5) is particularly suitable for a paint supply system including so-called hand-blown coating.

[0050] (6) A paint supply system comprising a paint flow path through which paint is supplied and a coating machine connected on the path of a branch path connected in parallel to the paint flow path. The swing device includes a cylinder tube connected in series to the branch path, a first bigg accommodated in the cylinder tube so as to be able to reciprocate, and the first big force. A pair of piston rods extending in opposite directions, a pair of rod covers provided at both ends of the cylinder tube for slidably guiding the piston rods, and fixed to the tip portions of the piston rods A pair of second biggs that seal the branch path, and an operation in which the pair of second big moves to one end side of the branch path and an action to move to the other end side of the branch path are alternated By being repeated in A paint supply system in which the paint in the branch path is swayed, and one of the second biggs comes into contact with the opposing rod cover and stops.

[0051] The paint supply system according to the invention of (6) includes a paint flow path, a coating machine, and a swinging device! Paint is supplied to the paint channel. The coating machine is connected on the way of a branch path connected in parallel to the paint flow path. The swing device swings the paint in the branch path.

[0052] In the paint supply system according to the invention of (6), the swing device has a cylinder tube, a first big wig, and a pair of second big wigs. Further, the swing device has a pair of piston rods and a pair of rod covers. The cylinder tube is connected in series to the branch path. The first big is accommodated in the cylinder tube so as to be able to reciprocate. The pair of piston rods extends in the opposite direction to the first piper. A pair of rod covers are provided at both ends of the cylinder tube, and each piston rod is slidably guided. The pair of second biggs are fixed to the tip portions of the pair of piston rods, and seal the branch path.

[0053] Then, in the paint supply system according to the invention of (6), the operation of moving the pair of second biggs to one end side of the branch path and the operation of moving to the other end side of the branch path are alternately repeated. As a result, the paint in the branch path is moved. In addition, either one of the second big bears comes into contact with the opposing rod force bar and stops. Here, the paint flow path is a so-called main line, and this main line force branch path, so-called branch line, is connected in parallel. For example, this branch path is bifurcated, with both tip ends connected to the paint flow path and the base end connected to the coating machine. It can also be said that the branch path bypasses the paint flow path, and that the flow path of the branch path terminates in the coating machine. Connected on the way.

[0055] The first big wig is preferably reciprocated by air pressure, and the first port is provided on one rod cover, and the second port is provided on the other rod cover. Then, by supplying compressed air to the first port and exhausting air in the cylinder tube from the second port, the first big wig moves in the first direction, and the pair of second big wigs disperses the paint in the branch path. Move to one end. On the other hand, by supplying compressed air to the second port and exhausting the air in the cylinder tube from the first port, the first big wig moves in the second direction, and the pair of second big wigs separates the paint. Move to the other end.

[0056] By switching the direction control valve provided at the extended ends of the first and second ports, the operation of moving to one end side of the branch path and the operation of moving to the other end side of the branch path are alternately repeated. By doing so, the pair of second biggs sway the paint in the branch path.

[0057] In general, the big is advantageous in that the moving distance is not restricted, but it is difficult to specify the stop position. Therefore, for example, a piece of metal is built in the big and the stop position is detected by a magnetic sensor or the like. The coating machine using CCV has a lot of tubes to be branched, and the tubes are generally densely packed. Therefore, the position detection method using a magnetic sensor etc. requires an electric circuit and is an economical magnetic sensor. Is also difficult to arrange.

[0058] Since the paint supply system according to the invention of (6) is configured such that the swinging device is mechanically configured so that the second bigg of either V or the shift comes into contact with the opposing rod force bar and stops. It is economical because it does not require an electric circuit such as stop position detection. In addition, since the components are arranged in series with the branch path, the swing device is compact, and even if a large number of tubes that form the branch path are densely packed, such as a coating machine using CCV, The moving device can be easily arranged. Further, since the swinging device has the second bigg at both ends, there is an advantage that the pressure balance is achieved and the thrust of the first bigg is small. [0059] (7) The branch path is connected to a plurality of the coating machines arranged in parallel so as to face each other along both sides of the coating line. The paint supply system according to the invention

[0060] In the paint supply system according to the present invention, the paint delivered from the pressure pump pump is stored in the buffer device and then supplied to the paint flow path, so that the paint flow is buffered and the instantaneous flow rate of the paint is reduced. It can be secured. In addition, when a volume reciprocating pump is used as the pressure pump, pulsation generated by the pressure pump can be prevented.

[0061] Further, the coating material supply system according to the present invention is provided with a swing device in the branch path to prevent sedimentation of the paint in the branch path. The swing device according to the present invention is economical and compact, and is suitable for a paint supply system in which a coating machine with a CCV is disposed. Further, the swing device according to the present invention has the biggs at both ends, so that there is an advantage that the pressure balance is achieved and the thrust for the swing is small.

Brief Description of Drawings

FIG. 1 is a piping diagram showing an embodiment of a paint supply system according to the present invention.

FIG. 2 is an enlarged view of a main part of the paint supply system according to the embodiment, and is a state diagram in which the swing device moves the paint in the branch path to one end side.

FIG. 3 is an enlarged view of a main part of the paint supply system according to the embodiment, and is a state diagram in which the swing device has moved the paint in the branch path to the other end side.

FIG. 4 is a piping diagram of a conventional paint supply system.

Explanation of symbols

[0063] 3 Paint channel

4 Shaking device

5 tanks

6 Pressure pump

7 Shock absorber

10 Paint supply system

21-22 coating machine 40 forks

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a piping diagram showing an embodiment of a paint supply system according to the present invention. Figure 2

FIG. 3 is an enlarged view of a main part of the paint supply system according to the embodiment, and is a state diagram in which the swing device moves the paint in the branch path to one end side. FIG. 3 is an enlarged view of a main part of the coating material supply system according to the embodiment, in which the swing device moves the coating material in the branch path to the other end side.

[0066] First, the configuration of the paint supply system according to the present invention will be described. In FIG. 1, the paint supply system 10 has a plurality of pairs of coating machines 21 and 22 arranged at predetermined intervals on both sides of the painting booth 1 provided in the painting line.

In FIG. 1, the first painting booth 11 is provided with a plurality of pairs of spray painting machines using painting guns, so-called hand-blown painting machines 21. In the second coating booth 12, a plurality of pairs of electrostatic coating machines 22 equipped with a rotary atomizing device are arranged. The electrostatic coating machine 22 is supported by a coating robot. The third painting booth 13 has a pair of hand-blown painting machines 21. Although FIG. 1 shows an embodiment in which different types of coating machines are arranged together, the present invention is not limited to this embodiment.

[0068] In FIG. 1, the paint supply pipe 31 is arranged on one side of the painting booth 1 in the length direction of the painting line, and the paint return pipe 32 is arranged on the other side of the painting booth 1. Has been. The downstream end of the paint supply pipe 31 communicates with the upstream end of the paint return pipe 32 at the line end of the paint line. In this specification, both the paint supply pipe 31 and the paint return pipe 32 are collectively referred to as a paint flow path 3. Here, the paint channel 3 is a so-called mainline.

In FIG. 1, the coating machines 21 and 22 are supplied with the paint via a plurality of branch paths 40 connected to the paint flow path 3. The branch path 40 is a so-called branch line, and is a tube as a substance. The branch path 40 is provided with a swinging device 4 for swinging the paint in the branch path 40 (see FIGS. 2 and 3). The configuration and operation of the swing device 4 will be described later.

In FIG. 1, the paint supply system 10 includes a tank 5, a pressure pump 6, and a shock absorber 7. ing. The paint channel 3 is supplied with paint from the tank 5 and can return the paint to the tank 5. The pressure pump 6 sucks the paint from the tank 5 and delivers the paint. The shock absorber 7 accommodates a constant volume of paint delivered from the pressure pump 6 and pumps the accommodated paint into the paint flow path 3 at a constant pressure.

In FIG. 1, paint is stored in the tank 5. The paint may be a water-based paint or an oil-based paint, and may be a mixed paint in which a pigment and a vehicle are mixed. An agitator 51 for agitating the mixed paint is provided in the tank 5 so that the pigment and the vehicle do not separate or settle and thicken. For example, the agitator 51 is operated by a hydraulic motor.

In FIG. 1, the paint supply system 10 includes a direction control valve 34. The direction control valve 34 can suck the paint from the tank 5 to the pressure feed pump 6 by switching the direction control valve 34, which is a three-way valve, to the first direction. When the direction control valve 34 is switched to the second direction, the flow path from the tank 5 to the pressure pump 6 is closed, and the paint can be returned from the paint flow path 3 to the tank 5. It is returned to the paint force S tank 5 through a back pressure valve 33 provided on the other end side of the paint flow path 3.

In FIG. 1, the pressure pump 6 uses a positive displacement pump. Volumetric reciprocating pumps include plunger pumps or diaphragm pumps. These pumps are generally inexpensive and are suitable for practical use because the paint does not deteriorate without the metallic pieces of the paint being crushed. Yes. When the pressure pump 6 is driven, the paint is sucked from the tank 5 and sent out. The paint delivered from the pressure pump 6 is accommodated in the shock absorber 7 via the filter 75.

In FIG. 1, the shock absorber 7 includes a container 71, a liquid level detector 72, and control means. Container 71 contains a certain volume of paint. The liquid level detector 72 detects the volume of the paint stored in the container 71. The control means receives the signal of the liquid level detector 72 and switches the direction control valve 34 so that the paint contained in the container 71 is maintained between the maximum capacity and the minimum capacity.

In FIG. 1, a container 71 is a cylindrical sealed container and is a pressure container. Then, the paint flows from a supply port 71 a provided at the bottom of the container 71, and the compressed fluid A is supplied from the top of the container 71. Applying pump 6 to the paint consumption of paint machine 21 When the supply amount of paint is large, the liquid level of the paint in the container 71 increases. When the supply quantity of paint in the pressure pump 6 is small, the liquid level of the paint in the container 71 decreases.

[0076] The maximum volume and the minimum volume of the container 71 are converted into the liquid level, and the maximum liquid level and the minimum liquid level are preset. In Figure 1, the paint fluctuates between a high level H and a low level L. The paint discharge port 71 b is provided between the low level L and the bottom of the container 71. The liquid level detector 72 converts the detected values of the high level H and low level L of the liquid level into electrical signals.

In FIG. 1, the control means includes a control panel 73. The control panel 73 receives the detection signal from the liquid level detector 72 and transmits a switching signal for switching the direction control valve 34. When the low level signal is transmitted to the control panel 73, the control panel 73 switches the direction control valve 34 in the first direction. The container 71 is then supplied with paint from the tank 5. When the no-level signal is transmitted to the control panel 73, the control panel 73 switches the direction control valve 34 to the second direction. Then, the paint can be returned from the paint flow path 3 to the tank 5.

In FIG. 1, the paint supply system 10 is provided with a compressed fluid source (not shown) for storing air or nitrogen gas. Further, a pressure regulating valve 74a and a direction switching valve 74b are connected in series between the compressed fluid source and the container 71. The container 71 is provided with a pressure gauge (not shown), and when the space in the container 71 becomes a predetermined pressure or less, the direction switching valve 74b is switched so that the compressed fluid A can be supplied to the container 71. When the space in the container 71 is within a predetermined pressure, the direction switching valve 74b is closed. When the space in the container 71 exceeds a predetermined pressure, the direction switching valve 74b is switched so that the compressed fluid A flows backward to the compressed fluid source side.

Thus, the shock absorber 7 includes the supply means 74 that supplies the compressed fluid A so that the space in the container 71 maintains a constant pressure. Here, the supply means 74 includes a compressed fluid source, includes a pressure regulating valve 74a and a direction switching valve 74b, includes a pressure gauge that detects the space pressure in the container 71, and controls the direction switching valve 74b. Can be included.

Next, the operation of the paint supply system according to the present invention will be described. The shock absorber 7 is a container 71 as a substance, and functions to accommodate a certain volume of paint delivered from the pressure pump 6. When the paint supply amount of the pressure pump 6 is large relative to the paint consumption of the coating machine 21 · 22, the capacity of the paint increases, and when the paint supply amount of the pressure pump 6 is small, the capacity of the paint increases. Decrease. Thus, the capacity of the paint in the container 71 varies.

The buffer device 7 has a maximum capacity so that the container 71 is not filled with paint.

Further, the minimum capacity is set so that the paint does not become empty in the container 71. The shock absorber 7 is controlled so that the paint in the container 71 varies between the maximum capacity and the maximum capacity. In the paint supply system 10 according to the present invention, the capacity of the pressure pump 6 is set so that the amount of paint supplied per unit time of the pressure pump 6 exceeds the amount of paint consumed per unit time of the coating machines 21 and 22. .

[0082] By supplying the compressed fluid A to the container 71, the shock absorber 7 can pressurize the paint, which is an uncompressed fluid, at a constant pressure regardless of the change in the capacity of the paint in the container 71. Then, the paint contained in the container 71 can be pumped to the paint channel 3 at a constant pressure. The paint stored in the container 71 is supplied to the paint flow path 3 at a constant flow rate determined by the pipe diameter and pressure of the paint flow path 3.

As described above, the paint supply system according to the present invention stores the paint delivered from the pressure pump in the buffer device and then supplies the paint to the paint flow path. That is, the paint flow is buffered. Therefore, the pulsation which generate | occur | produces with a capacity | capacitance reciprocating pressure pump can be prevented. The paint supply system according to the present invention is particularly suitable for a paint supply system including so-called hand-blown coating.

[0084] In addition, since the paint supply system according to the present invention pumps the paint contained in the shock absorber to the paint flow path at a constant pressure, for example, the canister may be filled with a large amount of paint. Because it is a short time, it can be averaged. In the paint supply system according to the present invention, it is also possible to secure an instantaneous flow rate of the paint by interposing a buffer device between the pressure feed pump and the main line. It can be said that it can be used with existing equipment.

[0085] The paint supply system according to the present invention receives the signal of the liquid level detector and switches the direction control valve so that the paint contained in the container maintains between the maximum capacity and the minimum capacity. Simple control is implemented. Furthermore, since the shock absorber includes supply means for supplying the compressed fluid so that the space in the container maintains a constant pressure, the space in the container can maintain the constant pressure with the compressed fluid. Compressed fluids have the advantage of a fast response time to a constant pressure with respect to varying paint capacities. Air or nitrogen gas is used as the compressed fluid. For example, the use of nitrogen gas, which is an inert gas, as the compressed fluid can prevent, for example, acidification of the paint.

Next, the configuration of the swing device according to the present invention will be described. 2 or 3, the swing device 4 has a cylinder tube 41, a first big 42, and a pair of second big 43a'43b. Further, the swing device 4 has a pair of piston rods 44a'44b and a pair of rod covers 45a'45b.

In FIG. 2 or FIG. 3, the cylinder tube 41 is connected in series to the branch path 40. The first big 42 is accommodated in the cylinder tube 41 so as to reciprocate. The pair of piston rods 44a'44b extend from the first big 42 in opposite directions. The pair of rod covers 45a'45b are provided at both ends of the cylinder tube 41, and guide the piston rods 44a'44b to be slidable. The pair of second big 43a'43b is fixed to the respective tip portions of the pair of piston rods 44a'44b, and seals the branch path 40.

In FIG. 1, the paint flow path 3 is a so-called main line, and this main line force branch path 40, so-called branch line, is connected in parallel. The branch path 40 is bifurcated, with both tip ends connected to the paint flow path 3 and base ends connected to the coating machines 21 and 22. It can also be said that the branch path 40 bypasses the paint flow path 3. It can be said that the flow path of the branch path 40 terminates in the coating machine 21 · 22. The coating machines 21 and 22 are connected on the way of the branch path 40 connected in parallel to the paint flow path 3.

[0089] In FIG. 2 or FIG. 3, the first big 42 is reciprocated by air pressure. The rod cover 45a is provided with a first port P1 serving as a compressed air flow path, and the rod cover 45b is provided with a second port P2 serving as a compressed air flow path. By supplying compressed air to the first port P1 and exhausting air in the cylinder tube 41 from the second port P2, the first big 42 moves in the first direction, and the pair of second big 43a '43b Move the paint to one end of the branch 40 (see Figure 2). On the other hand, by supplying compressed air to the second port P2 and exhausting air in the cylinder tube 41 from the first port P1, the first big 42 moves in the second direction, and a pair of second big 43a ' 43b moves the paint to the other end of the branch path 40 (see FIG. 3).

[0090] In FIG. 2 or FIG. 3, the directional control valve provided at the extended end of the first and second ports Ρ1 and Ρ2

By switching (not shown), the movement to one end of the branch path 40 and the branch path 4 The operation of moving to the other end side of 0 is alternately repeated, so that the paint in the pair of second big 43a'43b force branch path 40 is swayed.

Next, the operation of the swing device according to the present invention will be described. The paint supply system 10 according to the present invention mechanically configures the swing device 4 so as to come into contact with the rod cover 45a or 45b opposed to one of the second big 43a'43b forces and stop. This is economical because it does not require an electric circuit for detecting the stop position as in the prior art.

[0092] Further, the swing device 4 is compact because the components are arranged in series with the branch path 40, and a large number of tubes serving as the branch path 40 are densely packed like a coating machine using CCV. However, the swing device 4 can be easily arranged. Further, since the swing device 4 has a pair of second big 43a'43b at both ends, there is an advantage that the pressure balance is achieved and the thrust of the first big 42 is small.

[0093] For example, the outer diameter of the first big 42 is about 16 mm, and the operation of the first big 42 can be easily confirmed by forming a preferred cylinder tube made of transparent synthetic resin. The swaying device 4 may be operated only for a predetermined time period using a timer that may be steadily operated. Alternatively, the swing device 4 may be controlled to operate only when the coating machine is not in operation. In the embodiment shown in FIG. 1, the swinging device 4 is disposed in all the coating machines 21 22, but the swinging device 4 can be disposed as required. The swing device of the present invention is particularly useful for an electrostatic coating machine 22 equipped with a rotary atomizer using CCV.

[0094] The present invention is a paint supply system that can share a water-based paint or an oil-based paint, and in the branch line, in particular, a paint supply having a swing function in order to achieve uniformity so that the oil-based paint does not settle. Provide a system.

Claims

The scope of the claims

[1] A paint supply comprising a paint flow path through which paint is supplied from a tank and the paint can be returned to the tank, and a coating machine to which the paint is supplied through a branch path connected to the paint flow path. Supply system,

A pump that sucks the paint from the tank and delivers the paint;

A paint supply system comprising: a buffer device that contains a fixed volume of paint delivered from the pressure pump and pumps the contained paint into the paint flow path at a constant pressure.

[2] A direction that is interposed between the tank and the pressure pump and can be switched to a direction in which the paint flows from the tank to the pressure feed pump or a direction in which the paint returns from the paint flow path to the tank. With control valve,

The shock absorber includes a container for storing a fixed volume of paint, a liquid level detector for detecting the volume of the paint stored in the container, and the paint stored in the container between a maximum capacity and a minimum capacity. 2. The paint supply system according to claim 1, further comprising a control means for switching the direction control valve by receiving a signal from the liquid level detector so as to maintain the pressure.

[3] The paint supply system according to claim 2, wherein the shock absorber includes supply means for supplying a compressed fluid so that a space in the container maintains a constant pressure.

4. The paint supply system according to claim 3, wherein the compressed fluid is nitrogen gas.

[5] The paint supply system according to any one of [1] to [4], wherein the pressure pump is a volume reciprocating pump.

[6] A paint supply system comprising: a paint flow path through which paint is supplied; and a coating machine connected on the way of a branch path connected in parallel to the paint flow path;

A swaying device for swaying the paint in the branch path is provided,

The swing device includes a cylinder tube connected in series to the branch passage, a first bigg accommodated in the cylinder tube so as to be able to reciprocate, and a pair of piston rods extending in directions opposite to the first bigg force. A pair of rod covers provided at both ends of the cylinder tube for slidably guiding the piston ports, and a pair of second covers fixed to the tip ends of the piston rods to seal the branch passages. Big, and

The movement of the pair of second biggs to one end of the branch path and the other of the branch path The operation of moving to the end side is repeated alternately to move the paint in the branch path

The coating material supply system in which any one of the second biggs abuts against the opposing rod cover and stops.

The paint supply system according to any one of claims 1 to 6, wherein the branch path is connected to a plurality of the coating machines arranged side by side so as to face each other along both sides of the coating line.