JPH0245568Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Purpose of the invention [Technical field of the invention] The invention provides a valve device that drives a valve body with a piston;
In particular, the present invention relates to a piston-driven valve device used for controlling corrosive fluids such as chemical solutions.

[Prior art and its problems]

FIG. 6 is a sectional view of a conventional piston-driven valve device, in which an inlet 1 and an outlet 2 formed in a body B communicate through a valve hole 3, and a valve body 5 is built in a valve chamber 4. has been done. A cylinder 6 is mounted on the body B, and the upper end of the cylinder 6 is connected to a head cover 7.
is sealed. The valve body 5 is attached to the tip of a piston rod 9 connected to a piston 8 housed in the cylinder 6.

In a valve device that handles corrosive fluids such as chemical solutions, a valve body 5 is integrally molded at the tip of a bellows 10 as shown in the figure, and the bellows 10 covers the portion of the piston rod 9 exposed in the valve chamber 4. is taken. The base end 11 of the bellows 10 is clamped and fixed between the body B and the cylinder 6. The piston rod 9 is connected to the valve body 5 through a threaded portion 12 at the tip thereof.

In this configuration, when pressure fluid is supplied from the port 14 to the chamber 13 on the piston rod side of the cylinder 6, the piston 8 is pushed up against the return spring 15, the valve body 5 is raised by the piston rod 9, and the valve hole 3 opens. As a result, the controlled fluid passes through the path of inlet 1 → valve hole 3 → valve chamber 4 → outlet 2. The upper limit position of the valve body 5 is defined by the piston 8 moving a distance H until it hits the lower end of the head cover 7. When the port 14 is brought into the discharge state, the piston 8 is pushed down by the return spring 15, and the valve body 5 is pushed down by the piston rod 9, so that the valve hole 3 is closed.

As the fluid to be controlled passes through the valve chamber 4, the piston rod 9 is covered with a bellows 10, as described above, in order to prevent the piston rod 9 from being corroded by corrosive fluids. However, the piston 8 and piston rod 9 rotate due to vibrations and the like during the opening and closing operations of the valve body, causing the following problems.

(1) The bellows 10 becomes loose due to the rotation of the piston 8 and the piston rod 9, and the threaded portion of the bellows 10 is damaged. Further, as a result, the bellows 10 cannot follow the piston rod 9, and the bellows 10 cannot rise by the stroke H, resulting in insufficient opening of the valve hole 3 and insufficient flow rate.

(2) Due to the rotation of the piston 8 and the piston rod 9, an excessive twisting moment is applied to the bellows 10, causing severe deformation and damage to the bellows 10 and shortening its life. Particularly when handling corrosive fluids such as chemical solutions, if the bellows 10 is damaged, it becomes impossible to protect the piston rod 9, and the bellows 10
cannot achieve its purpose.

[Technical issues of the present invention]

The technical problem of this invention is to solve these problems with conventional piston-driven valve devices and prevent the piston and piston rod from rotating, thereby preventing insufficient flow and damage or deformation of the bellows. .

(b) Structure of the invention [Technical means of the invention] The technical means of the invention taken to solve this technical problem is to cover the tip of the piston rod with a bellows equipped with a valve body at the tip, In a valve device that drives a valve body with a piston connected to The other end is bent toward the rod cover side of the cylinder and engaged with the rod cover side.

[Effect of technical means]

According to this technical means, one end of the detent member is engaged with the piston, so that the detent member cannot rotate relative to the piston. In addition, the other end of the rotation prevention member is engaged with the rod cover part, so
The anti-rotation member cannot rotate relative to the rod cover. Therefore, even if a rotational force is generated in the piston or the piston rod, the rotation preventing member cannot rotate with respect to the piston or the rod cover, so the piston or the piston rod cannot rotate with respect to the rod cover.

Since the rotation prevention member is fixed to the piston side, the rotation prevention member also moves together, and the bent portion on the rod cover side slides on the engagement portion of the rod cover.

[Example of idea]

Next, how the valve device with a detent mechanism according to the present invention is actually implemented will be explained using examples. FIG. 1 is a longitudinal cross-sectional view showing an embodiment of a valve device with a detent mechanism according to the present invention, and the same parts as in the conventional example shown in FIG. 6 are given the same reference numerals. Second
The figure is an enlarged cross-sectional view of a main part of the valve device, FIG. 3 is a cross-sectional view taken along the line AA in FIG. 2, and FIG. 4 is a cross-sectional view taken along the line B-B in FIG. 2.

Reference numeral 16 denotes a rotation preventing member made of a plate material, with a mounting hole 17 opened in the center and one end bent upward, that is, toward the piston 8 side. The other end is bent downward, that is, toward the rod cover portion 61. On the other hand, the rod cover part 6 of the piston 8
A hole 19 into which the bent piece 18 of the detent member 16 fits is formed on the first side surface, and a flat chamfer is formed on the rod cover portion 61 so that the bent piece 20 is engaged therewith. That is, in order to form a communication path between the chamber 13 on the rod cover section 61 side of the cylinder 6 and the port 14, an annular groove 62 is formed on the surface of the rod cover section 61 on the piston 8 side. It communicates with port 14. Cylindrical portion 63 inside this groove 62
A flat portion 64 is formed by partially chamfering the outer surface of the plate. The bent piece 20 is bent so as to come into close contact with this flat portion 64.

The piston rod 9 is provided with a threaded rod 91 for connection with the piston 8, and is fixed to the piston 8 by inserting the threaded rod 91 into a hole in the center of the piston 8 and tightening it with a nut 21. In this embodiment, this threaded rod 91 is inserted into the mounting hole 17 of the rotation prevention member 16, and the rotation prevention member 16 is sandwiched between the piston rod 9 and the piston 8. At this time, the upwardly bent piece 18 of the detent member 16 is fitted into the hole 19 of the piston 8 in advance,
The downwardly bent piece 20 is engaged with the flat part 643 of the rod cover part 61.

In such a configuration, by fitting the upwardly bent piece 18 into the hole 19, the detent member 1
6 becomes unrotatable with respect to the piston 8, and the downwardly bent piece 20 is attached to the flat part 6 of the rod cover part 61.
4, the rotation preventing member 16 becomes unrotatable with respect to the rod cover portion 61 as well. Therefore, even if the piston 8 and the piston rod 9 try to rotate due to vibrations during the opening and closing operations of the valve body, the piston 8 and the piston rod 9 will not rotate because they are locked to the rod cover part 61 via the rotation prevention member 16. Can not.

Note that even if the piston 8 moves up by the stroke H, the downwardly bent piece 20 of the detent member 16 is sufficiently long so that it does not separate from the flat portion 64, and the concave groove 62
It is correspondingly deep enough.

Figure 5 shows the durability test data of the valve device with a detent mechanism according to the present invention and a conventional valve device, where A shows the characteristics of the conventional valve device, and B shows the valve device with a detent mechanism according to the present invention. It shows the characteristics of The results of testing on 5 samples each for both A and B show that the valve device with a detent mechanism according to the present invention did not exhibit any abnormality even after more than 3 million operations, but the conventional valve device had 3 Abnormalities such as bellows damage and insufficient flow have occurred.

(c) Effect of the invention As described above, according to the invention, the rotation prevention member is interposed between the piston or piston rod and the rod cover side, and the rotation prevention member and the piston side and the rod cover side respectively engage with each other, so that they are mutually engaged. It is regulated so that movement in the rotational direction is not possible. Therefore, even if rotational force is applied to the piston or piston rod due to vibrations when the valve body opens and closes, the piston rod will not be able to rotate because the piston side is locked to the rod cover side via the anti-rotation member. This prevents deformation and damage to the bellows covering the tip of the piston rod, prolongs the life of the bellows, and eliminates problems such as insufficient flow due to bellows abnormalities. Furthermore, when the piston 8 and the piston rod 9 rotate, the packing 22 such as the O-ring on the outer periphery of the piston 8 and the packing 23 on the outer periphery of the piston rod 9 are likely to be twisted and damaged.
Since they cannot rotate, these gaskets also have a long lifespan.

A key is also used as a means to permit axial movement and limit rotation, but in a piston-driven valve system, the use of a key makes sealing difficult.
However, by using the folding anti-rotation member of the present invention, it becomes possible to prevent rotation regardless of the seal portion, and it can be realized with a simple structure.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a valve device with a detent mechanism according to the present invention, FIG. 2 is an enlarged sectional view of the main part of the valve device, and FIG. 3 is a sectional view taken along line AA in FIG. 2.
Fig. 4 is a sectional view taken along line B-B in Fig. 2, Fig. 5 is a diagram comparing the characteristics of a conventional valve device and a valve device with a detent mechanism according to the present invention, and Fig. 6 is a vertical cross-sectional view showing the conventional valve device. It is a front view. In the figure, 5 is a valve body, 6 is a cylinder, 61
is a rod cover part, 62 is an annular groove, 63 is a cylindrical part, 64 is a flat part, 8 is a piston, 9 is a piston rod, 91 is a threaded rod, 10 is a bellows, 16
17 is a rotation prevention member, 17 is a mounting hole, 18, 20
19 indicates a bent piece, and 19 indicates a hole.

Claims (1)

[Scope of utility model registration request] In a valve device having a structure in which a bellows with a valve body at the tip covers the tip of a piston rod and a piston connected to the piston rod drives the valve body, the rotation prevention member is attached to the piston using a mounting hole drilled in the rotation prevention member. Or a valve device with a detent mechanism attached to the piston rod side, with one end of the detent member bent toward the piston and engaged with the piston, and the other end bent toward the rod cover of the cylinder and engaged with the rod cover. .