JPH0632212Y2 - Paint supply switching valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a paint supply switching valve for supplying paint of an appropriate color to a coating machine.

[Prior Art] With the increase in the number of colors applied to automobiles and the like, it is necessary to successively change the colors with a single coating machine, and a paint supply device that supplies different colors to a single coating machine. Is proposed.

FIG. 3 shows a schematic configuration diagram of the already proposed paint supply device, in which a plurality of paint supply switching valves 3A, 3B, 3C for supplying different color paint to the paint passage 2 leading to the coating machine 1 are provided. Then, these paint supply switching valves are selectively operated to supply the paint of a desired color to the coating machine 1 through the arbitrary switching valves. These paint supply switching valves allow the paint stored in the tank 4 to be supplied. The circulating path 6 is caused to flow by the pump 5 which is constantly driven to suppress the precipitation of the coloring metal powder in the paint. And
When the coating material is sent to the coating machine 1, the circulation passage 6 of any one of the coating material supply switching valves is closed and the sealing portion 8 closing the coating material outlet 7 is opened.

However, the sealing surface of the sealing portion 8 is easily scratched by the metal powder contained in the paint, which causes a leak.

The pressure of the paint by the pump 5 is not necessarily the same. For example, when the pressure of the paint of A color in the paint supply switching valve 3A is higher than the pressure of the paint of B color and C in the paint supply valves 3B and 3C, The high-pressure A-color paint flowing through the flow path 2 leaks into the valves 3B and 3C from scratches in the sealing portion 8 of the low-pressure paint supply switching valves 3B and 3C, and causes the circulation path 6 of these valves to flow. A serious accident may occur in which the colors of the B and C color paints mix through the tank 4 and change.

In order to prevent this accident, it is conceivable to install a check valve upstream of the sealing portion 8, but it is preferable to provide a separate check valve because it increases the cost of the entire device and increases the number of pipes. Absent. In addition, since the check valve operates with a differential pressure, when the flow rate is small like paint, the opening of the valve is small and dust is easily clogged, so there is also a problem that the check function cannot be fully exerted.

[Problems to be Solved by the Invention] An object of the present invention is to provide a paint supply switching valve that is free from the risk of color mixture due to paint leakage, by providing a backflow prevention member made of a soft material that can close the discharge port. It is to provide as something.

[Means for Solving the Problems] In order to achieve the above object, the paint supply switching valve of the present invention is
A valve rod having a paint inlet, a circulation port, a paint outlet, a discharge port that connects the paint inlet and the paint outlet, a seal part that disconnects the communication between the paint inlet and the circulation port, and a sealing part that opens and closes the paint outlet. And a circulation position for communicating the paint inlet and the circulation port by the operation of the valve rod and closing the paint outlet by the sealing portion to circulate the paint, and opening the paint outlet and providing the paint inlet by the sealing portion. In a paint supply switching valve that cuts off the communication with the circulation port and switches the paint from the paint outlet to the supply position for supplying the paint to the coating machine, in the valve rod of the paint supply switching valve, the discharge port at the circulation position of the valve rod. And a backflow preventing member made of a soft material for closing the communication between the paint outlet and the paint inlet and the circulation port.

[Operation] When the paint supply switching valve is in the circulation position for circulating the paint, the sealing portion and the backflow prevention member close the paint outlet and the discharge port to shut off the supply of the paint to the paint outlet and to supply the paint. When the switching valve is switched to the supply position, the backflow prevention member and the sealing portion open the discharge port and the paint outlet, and the paint is supplied to the paint outlet.

In this case, even if the paint flowing through the paint passage leaks from the seal part of the paint supply switching valve at the circulating position to the paint valve,
The backflow prevention member made of a soft material provided on the valve rod is easily displaced by the pressure of the leaked paint to close the discharge port and shut off the flow of the paint into the paint inlet and the circulation port. Discoloration can be reliably prevented.

Further, when the paint supply switching valve is switched to the supply position, the backflow preventing member is displaced by the pressure of the paint flowing through the switching valve to open the discharge port, so that dust clogging occurs even if the flow rate of the paint is small. There is no.

The backflow prevention member is less expensive than a separate check valve, hardly increases the cost, and does not require piping work.

[Embodiment] FIG. 1 shows a paint supply switching valve in an embodiment of the present invention, and FIG. 2 shows a schematic configuration diagram of the entire paint supply apparatus.

As shown in FIG. 2, this paint supply device is provided with a plurality of paint supply switching valves 11, ... For supplying paints of different colors to the paint flow passage 2 leading to the coating machine 1. By selectively operating the paint supply switching valve 11, ..., A paint of a desired color is supplied to the coating machine 1 from any paint supply switching valve. When changing the color to be coated, the base of the paint flow path 2 is changed. Pour a thinner or the like from the end toward the coating machine 1,
After cleaning the flow path 2, the paint of another color is pressure-fed to the coating machine 1 by operating the other paint supply switching valve 11.

The paint supply switching valve 11, ... Is provided with a switching unit 12 for switching the paint between a circulating position and a supply position, a sealing unit 13 for sealing the paint outlet 7, and a backflow prevention member 14 described later. Is switched to a circulation position, and the paint that is pumped from the tank by the pump 5 that is constantly driven is caused to flow in the circulation path 6 to suppress the precipitation of metal powder in the paint, and when the paint is sent to the coating machine 1,
The switching section 12 is switched to the supply position and the sealing section 13 and the backflow prevention member 14 are opened.

Next, the structure of the paint supply switching valve 11 will be described with reference to FIG.

Flow path member to which the valve body 16 of the paint supply switching valve 11 is attached
Reference numeral 17 denotes a coating flow path 2 having a rectangular cross section which leads to the coating machine 1 inside.
At the mounting position of the paint supply switching valve 11, a concave hole 17a for reaching the paint passage 2 for mounting the valve body 16 together with the valve seat base 18 is formed, and the inner surface of the paint passage 2 is In order to prevent the paint from adhering and facilitate the cleaning at the time of changing the color, it is preferable to perform mirror finishing.

The valve body 16 has a paint inlet 20 and a circulation port 21 at opposite positions.
Has a discharge port 22 communicating with the paint outlet 7 at a position orthogonal to these, and at the tip of a valve rod 23 penetrating the discharge port 22, the paint flow to a valve seat 18a provided on the valve seat base 18 A sealing portion 13 is formed to contact and separate from the road side to seal the paint outlet 7. The valve rod 23 constituting the switching unit 12 is an intermediate paint inlet.
Seal part 25 that comes in contact with and separates from the seal seat 24 between the 20 and the circulation port 21
And a sealing portion 13 that seals between the paint inlet 20 at the tip and the flow path 2, and a seal between the discharge ports 22 to prevent mixing of paint of another color into the circulation port 21. The seat 27 is provided with a flange 27 that comes in contact with and separates from the seat 26, and the backflow prevention member 14 that opens and closes the discharge port 22 is attached to the flange 27.

The backflow prevention member 14 is formed of a soft material such as a soft synthetic resin that withstands paint and thinner, and the flange 27 has a seal seat 26.
When it comes close to the seal seat 26, it abuts the seal seat 26 to prevent the paint from leaking from the paint outlet 7 to the circulation port 21, and when the flange 27 separates from the seal seat 26, the backflow prevention member 14 opens the seal seat 26.

The bonnet 30 covering the valve body 16 is provided with a partition plate 31 between the valve body 16 and a pilot port 35 and a breathing port 36 are opened in a pressure chamber 33 and a breathing chamber 34 defined by a piston 32, respectively, and a seal ring. The piston 32 is fixed to the tip of the valve rod 33 protruding from the partition plate 31 via 38, and the return spring 39 is compressed in the breathing chamber 34.

In the paint supply switching valve having the above configuration, in the state where the pilot fluid is not supplied to the pilot port 35 of the paint supply switching valve 11, the seal portion 25 opens the seal seat 24 by the urging force of the return spring 39, The sealing portion 13 is the valve seat 18a
The backflow prevention member 14 seals the seal seats 26, and the paint circulates in the circulation path 6. In this case, even if the pressure of the other-color paint that is pressure-fed to the paint passage 2 from the other paint supply switching valve is high and leaks from the sealing portion 13, the backflow prevention member 14 made of a soft material due to the pressure of this paint. Seal seat 26
Is firmly sealed, it is possible to reliably prevent the mixing of the paint of another color into the circulation path 6.

When pilot air is supplied to the pilot port 35,
The piston 32 and the valve rod 23 move downward in the figure, and the contact of the seal portion 25 with the seal seat 24 causes the switching portion 12 to move to the inlet 20 and the outlet 22.
Switch to the communication position where
Opens the seal seat 26 and the sealing portion 13 opens the valve seat 18a, so that the paint is pumped into the paint flow path 2. Therefore,
The backflow prevention member 14 does not become clogged with dust or the like even when the flow rate is low, is cheaper than a separate check valve, and does not require piping. In this case, the sealing of the seal seat 24 by the seal portion 25 does not necessarily need to be reliably performed.

[Advantage of the Invention] The paint supply switching valve of the present invention is provided with a backflow preventing member made of a soft material that blocks the leakage of the paint from the paint outlet to the paint inlet and the circulation port, so that the paint circulating It is possible to reliably prevent the paint of another color from mixing into the supply switching valve.

Further, the backflow prevention member made of a soft material is cheaper than a separate check valve and hardly increases the cost, and the number of pipes can be omitted, and the switching position between the valve rod supply position and the circulation position can be changed. Since it can be easily displaced to open and close the discharge port, there is no risk of dust clogging.

[Brief description of drawings]

FIG. 1 is a sectional view of a paint supply switching valve according to an embodiment of the present invention, FIG. 2 is a block diagram showing the overall structure, and FIG. 3 is a block diagram of a conventional paint supply device. 7 ... Paint outlet, 11 ... Paint supply switching valve, 13 ... Sealing part, 14 ... Backflow prevention member, 20 ... Paint inlet, 21 ... Circulation port, 22 ... Discharge port, 23 ... Valve Stick, 25 …… Seal part.

Claims (1)

[Scope of utility model registration request] 1. A paint inlet, a circulation port, a paint outlet, a discharge port for communicating the paint inlet and the paint outlet, a seal portion for disconnecting the communication between the paint inlet and the circulation port, and a seal for opening and closing the paint outlet. A valve rod having a portion, and a circulation position for circulating the paint by operating the valve rod to connect the paint inlet and the circulation port and to close the paint outlet by the sealing portion;
In a paint supply switching valve that opens to the paint outlet and shuts off the communication between the paint inlet and the circulation port by the seal part and switches to the supply position for supplying the paint from the paint outlet to the coating machine, the valve rod of the paint supply switching valve In addition, a backflow prevention member made of a soft material is provided to close the discharge port at the circulation position of the valve rod to block the communication between the paint outlet and the paint inlet and the circulation port. Switching valve.