JP6727518B2 - Spray device and method for preventing precipitation of coating liquid - Google Patents

Description

The present invention relates to a spray device, and more particularly to a spray device for preventing the precipitation of the coating liquid and improving the durability of a piping system for supplying the coating liquid, a method for preventing the precipitation of the coating liquid in the spray device, or a cleaning of the coating liquid in the spray device. Regarding the method.

For example, molds and cores (sand molds for making hollows in molded products) used when manufacturing cast products are sprayed with a mold release agent in advance in order to enhance the mold releasability of the product. .. The coating liquid used for such a release agent is generally a mixture of solid fine particles (powder) in a solution.

By the way, when a mixed solution of powder and solution is used for a spray gun, if the coating solution stays in the piping route, the powder will settle in the staying part, causing factors such as sticking and blockage in the route. Become. Under such a background, conventionally, a spray gun has been proposed in which the coating liquid is circulated to prevent precipitation even when a spray is not used (for example, refer to Patent Documents 1 and 2).

JP, 2006-218450, A JP, 2006-055736, A

However, in the conventional structure in which the coating solution is circulated, it is necessary to provide the coating solution supply port and the return port in the spray gun body, and at least two pipes are required to connect them. In addition, a tank for storing the coating solution, an agitator for preventing the coating solution from settling in the tank, a pump for pumping the coating solution, and instruments for controlling the flow rate and pressure of the coating solution are provided in the circulation path. It is necessary, and the piping structure connecting them becomes complicated.

As the circulation path becomes longer or the path becomes more complicated in this way, the number of places where the coating liquid easily accumulates such as the bent portion of the pipe increases, and the chance of causing the coating liquid to flow poorly increases. In addition, there is also a problem that solid fine particles (powder) mixed in the coating liquid damage these fluid devices and sensors, resulting in shortened life. Moreover, maintenance workability of such a long and complicated pipe is not always easy.

The present invention has been made in view of such conventional problems, and is a highly practical technique that prevents sedimentation and the like in the path of the coating liquid in a spray device and is superior in maintainability and durability as compared with the related art. Is intended to provide.

In order to solve the above-mentioned problems, the present invention provides a spray gun having a nozzle hole that opens and closes with a needle valve, stores the coating liquid, and supplies the coating liquid to a valve chamber in the spray gun. A spray device having a cassette tank closed so as to be stored in a pressurized state, and an air supply path capable of supplying air to the valve chamber is formed in the main body of the spray gun.

In the above structure, it is preferable that the spray tank of the spray device is detachably attached to the spray gun through the coupler.

Further, it is preferable that the coupler is provided with a lock valve that automatically closes when the cassette tank is removed.

Further, it is preferable that the cassette tank is sealed so as to store the coating liquid under pressure.

Further, it is preferable that a check valve is provided in the air supply passage to flow only air to a side for supplying air into the valve chamber.

Further, the present invention provides a spray gun having a spray gun having a nozzle hole which is opened and closed by a needle valve, and a cassette tank which stores a coating solution and supplies the coating solution to a valve chamber in the spray gun. A method of prevention, wherein the cassette tank is sealed so as to store the coating liquid in a pressurized state, and when the needle valve is closed, air is pressurized through an air supply path communicating with the valve chamber. It is a method for preventing the precipitation of a coating liquid, which comprises stirring the coating liquid in the cassette tank by supplying it.

According to the present invention, by pressurizing and supplying air to the valve chamber of the spray gun through the air supply passage, the spray gun is agitated and the coating solution stored in the cassette tank is agitated to prevent precipitation of the coating solution. You can Further, the path of the coating liquid can be simplified, and the durability and maintainability of the device can be improved.

It is a figure which illustrates the spray apparatus by one Embodiment of this invention. It is a block diagram which illustrates the structure of the release agent and the supply piping of air connected to a spray apparatus. It is a figure for demonstrating the method of throwing a mold release agent into a cassette tank. It is a figure for demonstrating the cleaning method of a spray gun. It is a figure for demonstrating the method of preventing stirring and precipitation of a mold release agent in a spray apparatus. It is a figure for demonstrating the spraying operation of a spray apparatus.

Hereinafter, preferred embodiments of a spray device according to the present invention will be described with reference to the drawings. Here, a spray device 1 for applying a mold release agent, which is a mixed liquid of solid fine particles, to the surface of a mold or a sand mold (core) used when manufacturing a cast product will be described. However, the present invention is not limited to the embodiments described here, for example, a spray for painting the body of an automobile (including color painting, metallic painting, undercoating, anticorrosion treatment, etc.), or a coating material for building materials such as outer walls. It can be applied in various fields such as a spray for spraying.

FIG. 1 is a diagram illustrating a spray device 1 according to an embodiment of the present invention. The spray device 1 includes a spray gun 10, a cassette tank 20 that stores a release agent that is a coating liquid, and a coupler 30 that detachably attaches the cassette tank 20 to the spray gun 10. Note that, in FIG. 1, a cross section thereof is schematically shown in order to explain the structure of the spray gun 10 main body in an easily understandable manner.

The spray gun 10 includes a substantially cylindrical gun main body 110, a nozzle head 120 provided on the front side of the gun main body 110, and a valve opening/closing drive unit 130 formed at a rear portion of the gun main body 110.

FIG. 1 illustrates a needle valve type nozzle head 120 used in a general spray gun. In the case of this embodiment, a spray port 123 is formed at the tip of the nozzle head 120. The spray port 123 is composed of a nozzle hole 121 that ejects a release agent and an air hole 122 that surrounds the nozzle hole 121 in an annular shape. .. A needle valve 111a having a tapered shape is inserted into the nozzle hole 121 so as to advance and retract from the gun body 110 side. A valve shaft 111 integrally having a needle valve 111a is slidably supported in the gun body 110 and is driven back and forth by a valve opening/closing drive unit 130 described later. That is, when the needle valve 111a is retracted by the valve opening/closing drive unit 130, the nozzle hole 121 is opened to allow the release agent to be ejected, and when the needle valve 111a is advanced, the nozzle hole 121 is narrowed and finally closed. Is configured.

The annular air hole 122 communicates with the air supply port 125 via the air chamber 124. That is, when air (atomized air Aat described later) is pressurized and supplied from the air supply port 125, atomized air is ejected from the air hole 122 toward the front of the nozzle head 120.

The mold release agent ejected forward from the nozzle hole 121 by opening the needle valve mixes with atomized air ejected from the air hole 122 to form a spray flow, and at the same time, the spray flow is sucked up by the negative pressure effect of the air flow. And spread in a cone. Even if the atomizing air is adjusted so as to direct the spray direction of the atomized air toward the center line of the nozzle hole 121 to suppress the diffusion angle of the spray flow and increase the density of the spray flow. Good.

On the outer peripheral portion of the nozzle head 120 of the present embodiment, two protruding portions 128 that project forward (spraying direction) and face each other toward the center of the head are formed. The inner surface of the protrusion 128 is a tapered surface 128a, and a pattern air hole 126 is provided in each tapered surface 128a.

The pattern air hole 126 communicates with the air supply port 127. When air (pattern air Apt described later) is pressurized and supplied from the air supply port 127, pattern forming air is ejected from the pattern air hole 126. For example, by providing each of the pattern air holes 126 so as to be inclined toward the center line of the spray flow, the pattern forming air is blown against the spray flow from above and below to form a fan-shaped spray flow having a flat elliptical coating surface. can do.

A liquid chamber 112 which is a valve chamber communicating with the nozzle hole 121 is formed in the gun body 110. A valve shaft 111 having a needle valve 111a at its tip is slidably provided on the gun body 110 through the liquid chamber 112. In the cassette tank 20 connected to the spray gun 10 via the coupler 30, a release agent is stored under pressure as described later, and the release agent is supplied from the liquid supply port 115 provided in the gun body 110. Is pressurized and supplied to the liquid chamber 112.

Further, the gun body 110 is formed with an air supply path 113 that communicates with the liquid chamber 112 and can supply compressed air (agitating air Amx/purge air Apg described later) to the liquid chamber 112. The air supply path 113 is provided with a check valve 114 that allows pressurized supply of air and prevents leakage of the release agent from the liquid chamber 112 and backflow. In addition to the check valve, a lock valve that closes the air supply passage 113 during spraying or a blind (blind) screw that completely closes the air supply passage 113 may be attached if necessary.

At the rear part of the gun body 110, a valve opening/closing drive unit 130 is formed which moves the valve shaft 111 forward and backward to control the nozzle hole 121 to open and close. The valve opening/closing drive unit 130 includes a cylinder portion 131, a piston portion 111b formed at a rear end of the valve shaft 111, and a spring 133 interposed in the cylinder portion 131 between the piston portion 111b and the end cap 132 in a compressed state. And is configured. The spring 133 constantly biases the piston portion 111b toward the side where the needle valve 111a closes the nozzle hole 121 due to its elastic repulsive force.

When air (control air Act described later) is supplied to the air supply port 134, the pressure causes the valve shaft 111 to retreat against the repulsive force of the spring 133. At this time, the needle valve 111a is retracted to a position where the pressure of the control air and the elastic repulsive force of the spring 133 are balanced, whereby the nozzle hole 121 is opened. That is, the throttle amount of the needle valve, that is, the flow rate of the release agent ejected from the nozzle hole 121 is controlled according to the pressure of the control air.

The valve opening/closing drive unit 130 according to the present embodiment operates the air cylinder according to the pressure of the control air. However, a solenoid is provided in the valve opening/closing drive unit to drive the needle valve according to the current supplied to the solenoid. It may be one that controls the opening of the nozzle hole.

The cassette tank 20 has a closed structure capable of storing a release agent (coating liquid) under pressure. The coupler 30 is a removable joint such as a quick coupler. The coupler 30 is provided with a lock valve that automatically closes when the cassette tank 20 is removed.

FIG. 2 is a block diagram illustrating the configuration of the release agent and air supply pipes connected to the spray device 1. In the present embodiment, the air supply source 201 of the stirring air Amx and the purge air Apg, the air supply source 202 of the pattern air Apt, the air supply source 203 of the atomizing air Aat, and the air supply source 204 of the control air Act are connected to the spray gun 10. ing. Although the air supply sources 201 to 204 may be respectively configured by different compressors, all or a part of the air supply sources 201 to 204 may be provided by a circuit that divides the compressed air supplied by one compressor by a manifold. May be configured.

The spray device 1 of the present embodiment is not provided with a circulation path for the coating liquid (release agent) as in the conventional case. In addition to that, as shown in FIG. 2, the supply path of the release agent to the spray gun 10 is simplified only by the cassette tank 20 and the coupler 30. As described above, by simplifying the supply path of the coating liquid (release agent), the chances of damage due to solid fine particles mixed in the coating liquid are reduced, and as a result, the life of the spray device 1 can be extended. .. Further, for example, by using the detachable coupler 30 such as a quick coupler, the spray gun 10 and the cassette tank 20 can be easily separated and coupled, and maintenance workability such as cleaning is improved.

Next, a method of using the spray device 1 according to the present embodiment and its effects will be described.
First, as shown in FIG. 3, the liquid injection nozzle 40 is attached to the liquid injection unit 22 of the cassette tank 20, and the release agent M, which is the coating liquid, is injected into the tank body 21. The tank body 21 has a closed structure so that the release agent M is stored under pressure. Therefore, the back pressure in the space of the tank body 21 increases as the amount of the release agent M added increases, but the back pressure is maintained at a constant high pressure by the relief valve 23 provided on the upper portion of the tank body 21. ..

In order to maintain stable pressurization of the tank main body 21 in this way and to stably supply the release agent, and to confine the air pressure applied later, the liquid injection part 22 is provided with a reverse A stop valve (check valve) is preferably provided. Further, in order to ensure the convenience of liquid supply and maintenance, it is preferable that the liquid take-out nipple 24 below the cassette tank 20 is provided with a lock valve that automatically closes when the coupler 30 is removed.

In order to secure a space for air to be added later, it is preferable to add a mold release agent in an amount of about 3/4 from the full state to the tank body 21. That is, it is preferable that the compressed air for ejecting the release agent from the nozzle holes 121 is enclosed in at least about 1/3 of the space in the tank body 21.

On the other hand, as shown in FIG. 4, the inside of the spray gun 10 can be cleaned with the cassette tank 20 removed. For example, the control air Act can be applied to the valve opening/closing drive unit 130 to open the needle valve 111a, and in that state, the purge air Apg can be pressurized and supplied to the air supply passage 113. The coupler 30 is provided with a lock valve that automatically closes when the cassette tank 20 is removed, so that the mold release agent remaining in the liquid chamber 112 or the narrow valve chamber 112 ′ around the needle valve 111 a is discharged together with the purge air Apg. The holes 121 are vigorously discharged. Thereby, the inside of the spray gun 10 can be easily cleaned.

Next, as shown in FIG. 5, the cassette tank 20 is connected to the coupler 30 and attached to the spray gun 10. The cassette tank 20 is located higher than the main body of the spray gun 10. As described above, if the control air is not supplied to the valve opening/closing drive unit 130 (the air supply port 134), the needle valve 111a is closed by the elastic repulsive force of the spring 133. In this state, when the stirring air Amx is supplied from the air supply path 113, the air moves toward the cassette tank 20 through the coupler 30 and generates bubbles rising in the release agent M in the tank body 21. As a result, the release agent M is agitated, and it is possible to effectively prevent the precipitation and sticking of the solid fine particles on the bottom of the tank body 21.

In addition, in the spray device 1 of the present embodiment, the liquid level in the cassette tank 20 is lowered by the consumption of the release agent, and the back pressure Pc is also reduced accordingly. However, the back pressure Pc of the tank body 21 is returned to a high pressure while cleaning the inside of the spray gun 10 and preventing the inside of the cassette tank 20 from being settled by, for example, supplying the stirring air Amx at every interval between coating processes. It can be stored as the energy used to eject the release agent in the process of.

The spray device 1 of the present embodiment can perform the spraying operation by attaching the cassette tank 20 to the spray gun 10 as shown in FIG. When the cassette tank 20 is connected to the coupler 30, the lock valve in the coupler 30 is opened and communicated, and the mold release agent M in a pressurized state is filled in the liquid chamber 112 which is the valve chamber of the spray gun 10 in the cassette tank 20. .. Then, by supplying control air Act of a predetermined pressure from the air supply port 134 of the spray gun 10 and opening the needle valve 111a, the release agent is vigorously ejected from the nozzle hole 121 by the high back pressure Pc in the cassette tank 20.

At the same time, by atomizing air Aat from the nozzle hole 121, the liquid release agent is atomized into a spray flow. Further, the pattern air Apt can be jetted according to the application of application to form a fan-shaped spray flow having a flat elliptical application surface, for example.

1 Spray Device 10 Spray Gun 20 Cassette Tank 21 Tank Body 22 Liquid Injecting Section 24 Liquid Extraction Nipple 30 Coupler 110 Gun Body 111 Valve Shaft 111a Needle Valve 112 Liquid Chamber (Valve Chamber)
113 Air Supply Path 115 Liquid Supply Port 120 Nozzle Head 121 Nozzle Hole 122 Air Hole 123 Spray Hole 126 Pattern Air Hole 130 Valve Opening/Closing Drive Unit 133 Spring 134 Air Supply Port

Claims (6)

A spray gun having a nozzle hole that opens and closes with a needle valve, and a cassette tank that is sealed so as to store the coating liquid and supply the coating liquid to a valve chamber in the spray gun under pressure. And a spray device in which an air supply path capable of supplying air to the valve chamber is formed in the main body of the spray gun. The spray device according to claim 1, wherein the cassette tank is detachably attached to the spray gun via a coupler. The spray device according to claim 2, wherein the coupler is provided with a lock valve that automatically closes when the cassette tank is removed. The spray device according to any one of claims 1 to 3, wherein the cassette tank is sealed so as to store the coating liquid in a pressurized state. The spray device according to any one of claims 1 to 4, wherein a check valve is provided in the air supply path to flow air only to a side for supplying air into the valve chamber. A method for preventing the precipitation of a coating liquid in a spray device comprising a spray gun having a nozzle hole which is opened and closed by a needle valve, and a cassette tank which stores the coating liquid and supplies the coating liquid to a valve chamber in the spray gun,
By sealing the cassette tank so as to store the coating liquid in a pressurized state and, when closing the needle valve, pressurizing and supplying air through an air supply path communicating with the valve chamber, A method for preventing precipitation of a coating solution, which comprises stirring the coating solution in a cassette tank.