JP2665071B2 - Liquid control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid control valve.
In particular, the present invention relates to a liquid control valve in which an on-off valve and a suck-back valve are integrated.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view of a fluid control valve showing an example of the prior art. Conventionally, as shown in FIG. 3, for example, this type of liquid control valve includes a valve body 1 in which a fluid path is formed between a valve seat of an on-off valve and a valve seat of a suck-back valve, and a fluid flowing therethrough. A main body 2 of an on-off valve that opens and closes a valve seat, a valve body 3 of a suck-back valve that increases and decreases the volume of a fluid path, pistons 4 and 5 that drive each valve body, and a cylinder on which the pistons 4 and 5 slide. A pneumatic cylinder having a compression coil spring 8 for returning the parts 6, 7 and the pistons 4, 5 to a fixed position, a stroke adjusting screw 10 for adjusting the amount of movement of the valve body 3 of the suck back valve, and a lock nut 11. Have been. The liquid control valve includes a solenoid valve 12 for controlling high-pressure air that operates an on-off valve and a suck-back valve, a check valve with a variable throttle 13 for adjusting the moving speed of the suck-back valve, and air to each cylinder. An air pipe 14 to be sent is attached.

Next, the operation of the liquid control valve will be described. Here, FIG. 3 shows a state where the valve element driving high-pressure air is turned off. First, the solenoid valve 12 is switched, and when high-pressure air enters, the piston 4 for driving the valve body of the on-off valve is moved by the coil spring 8.
b, the piston 5 for driving the valve body of the suck-back valve moves downward. This causes the liquid to flow from the inlet to the outlet, as indicated by the arrow. Next, when the solenoid valve 12 is switched and high-pressure air is cut off, the on-off valve / valve drive piston 4 moves downward due to the repulsion of the coil spring 8b, and stops the flow of liquid. On the other hand, the piston 5 for driving the suck-back valve body is a check valve 13 with a variable throttle.
Moves upward slowly, increases the volume of the fluid path portion, pulls back the liquid on the outlet side (suck back operation), and returns to the state shown in FIG.

[0004]

This conventional liquid control valve requires a fluid path for each valve and a passage connecting them, so that it is difficult to reduce the volume of that part. Met. Also, valve seats and valves for opening and closing these flow paths must be arranged in the middle of these fluid paths, and it is difficult to reduce the size of the valves themselves.

[0005] It is an object of the present invention to provide a smaller liquid control valve that overcomes such problems.

[0006]

A liquid control valve according to the present invention includes a mechanism for opening and closing a valve seat by a first piston that slides in a first cylinder, and a fluid path after the valve seat. A liquid control valve having a suckback valve mechanism having a second piston that deforms a valve body that expands the pressure and a second cylinder on which the second piston slides, so as to surround the periphery of the valve seat. Wherein the fluid path portion is formed, and the first piston and cylinder and the second piston and cylinder are coaxially assembled.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIGS. 1A to 1C are sectional views showing the operation sequence of an embodiment of a liquid control valve according to the present invention. As shown in FIG. 1, the liquid control valve includes a valve body 1a having a fluid path formed around an opening of a valve seat, which is a liquid outflow / inlet, a valve seat and a fluid path of the valve body 1a. A valve body 2a for covering the valve body, a cylinder part 7a for mounting the valve body 2a between the valve body 1, and sliding in the cylinder part 7a,
A piston 5a for moving a portion of the valve body 2a corresponding to the fluid path portion in one direction, a coil spring 8a mounted in the cylinder portion 7a and applying a repulsive force to the piston 5a, and a lock nut 11a for the cylinder portion 7a. And a valve body 2a corresponding to the valve seat of the valve body 1 is moved to open and close the opening of the valve seat, and the tip is a piston 5a. , And a coil spring 8b incorporated between the other end of the piston 4a and the inner wall of the cylinder 6a.

That is, the suck back valve portion and the opening / closing valve portion have a coaxial structure. The adjustment of the suck-back amount of the suck-back valve portion is performed by a screw portion for connecting the cylinder portion 6a and the cylinder portion 7a. When the adjustment of the suck-back amount is determined, it is fixed by the lock nut 11a.

Next, the operation of the liquid control valve will be described. First, as shown in FIG. 1B, the solenoid valve 12 is switched, and high-pressure air is introduced into the cylinder 6a. As a result, the piston 4a moves upward against the coil spring 8b. Then, the portion of the valve body 2a corresponding to the valve seat is raised, the opening of the valve seat is made clear, and the liquid flows in the direction of the arrow (valve opening operation).

Next, when the solenoid valve 12 is switched and high-pressure air is cut off, the piston 4a moves downward due to the repulsive force of the coil spring 8b, and the portion of the valve body 21 corresponding to the valve seat is moved to the valve seat. To stop the flow of liquid (valve closing operation).
On the other hand, the piston 5a of the suck back valve portion moves slowly upward by the action of the check valve 13 with variable tightening,
The volume of the fluid path around the valve seat is increased, and the liquid on the outlet side is drawn back (suck back operation).

FIGS. 2A to 2C are sectional views showing the operation sequence of another embodiment of the liquid control valve of the present invention. As shown in FIG. 2, the liquid control valve is disposed between a valve body 1b having cylinder portions 6b and 7b at both ends on which pistons 4b and 5b slide, and between the cylinder portions 6b and 7b. A valve body 3a in which a valve seat having an opening serving as an inflow port and a fluid path formed by a bellows 17b surrounding the periphery of the valve seat; a valve body 3a and a valve body 1;
b and a valve element 2b having a valve closing the opening.

The valve body 2b is connected to one end of the piston 4b, and closes the opening of the valve seat by the repulsive force of the coil spring 8b. Further, the tip of the piston 5b of the suck back valve portion is connected to the valve body 3a.
The valve body 3a is moved by the movement of b, and the volume of the fluid path is changed by the expansion and contraction of the bellows 17b. On the other hand, valve body 2
Reference numeral b denotes a bellows 17a and a flange portion which is sandwiched and fixed between the bellows 17a, and is hermetically attached so that liquid does not enter the cylinder portion 6b.

Next, the operation of the liquid control valve will be described. First, as shown in FIG. 2B, when high-pressure air enters the air port 15 by switching the solenoid valve, the piston 4
b moves upward against the coil spring 8b. As a result, the valve body 2b moves upward, the bellows 17a contracts, the opening of the valve seat opens, and the liquid flows in the direction of the arrow.

Next, as shown in FIG. 2C, the solenoid valve is switched, and the supply of high-pressure air to the air port 15 is cut off. As a result, the piston 4b moves downward by the repulsive force of the coil spring 8b, closes the opening of the valve seat, and stops the flow of the liquid. At this time, the air exhausted from the air port 16 is delayed due to the action of the check valve and the throttle valve, and as shown in FIG. 2A, the piston 5b descends and the valve body 3a is moved. The bellows 17b expands, increasing the volume of the fluid path surrounded by the bellows 17b and sucking back the liquid that is about to flow out.

This liquid valve also incorporates a suck back and an open / close valve at the same time, is provided with a valve mechanism in the middle, and can be downsized as in the above-described embodiment.

[0017]

As described above, according to the present invention, the fluid passage is formed so as to surround the periphery of the opening of the valve seat, and the piston shaft for operating the valve element for opening and closing the opening of the valve seat and the fluid By providing a piston shaft for operating a valve body that changes the volume of the passage portion coaxially and by further providing a cylinder portion on which the piston slides on the same shaft, the two valve mechanisms can be stacked and assembled. This has the effect that a smaller liquid control valve can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an operation sequence of an embodiment of a liquid control valve according to the present invention.

FIG. 2 is a sectional view showing the operation sequence of another embodiment of the liquid control valve of the present invention.

FIG. 3 is a cross-sectional view of a liquid control valve showing an example of the related art.

[Explanation of symbols]

 1, 1a, 1b Valve body 2, 2a, 2b, 3, 3a Valve body 4, 4a, 4b, 5, 5a, 5b Piston 6, 6a, 6b, 7, 7a, 7b Cylinder part 8a, 8b Coil spring 9 O Ring 10 Screw 11 Lock nut 12 Solenoid valve 13 Check valve 14 Air piping 15, 16 Air port 17a, 17b Bellow

Claims (1)

(57) [Claims] A first piston that slides in a first cylinder to open and close a valve seat; a second piston that deforms a valve body that expands a fluid path after the valve seat; A liquid control valve including a suck-back valve mechanism having a second cylinder on which a second piston slides, wherein the fluid path portion is formed so as to surround a periphery of the valve seat portion, and A liquid control valve, wherein the piston and the cylinder and the second piston and the cylinder are incorporated coaxially.