JPS5814286Y2 - butterfly valve - Google Patents

Description

[Detailed description of the invention] This invention relates to a butterfly valve installed in a gas pipeline or the like.

Conventional valves of this type (Japanese Unexamined Patent Publication No. 50-92520, 5
2. 65941) has the structure shown in FIG. You will be forcibly guided along the

That is, pin a is guided along an arc of approximately 90 degrees around the valve stem 38 and whose radius is the effective length of the drive arm 36, whereas the axis of pin b is at the same time guided at a significantly shorter radius. 30 about the pivot axis defined by pin C.

Due to the fact that both the drive arm 36 and the link 30 have their starting positions parallel to each other and the angle of inclination is small, the movement of both parts relative to the valve plate 33 is at the beginning of the movement trajectory controlled by the drive arm as well as the link. This is done substantially tangentially to the circle drawn, but in substantially the same manner, so that the valve plate 33 in the chain line position is separated substantially perpendicularly from the valve body valve seat 32.

Therefore, near the valve closed position, the drive arm 36 is connected to the link 30.
It works as a nearly parallelogram link mechanism.

However, as the valve plate gradually moves away from the closed position,
Since the radius of the link 30 is smaller than the radius of the drive arm 36, the change in motion becomes noticeable, and the valve plate 33
Immediately after separation from pin b, the axis of pin b begins to deflect additionally to the side, so that valve plate 33 changes from an initially approximately vertical separation movement to a circular movement as the adjustment angle of the drive arm increases. However, during this movement, the line connecting pins b and pins C of link 30 gradually comes to intersect the line connecting pin a and the valve shaft of the drive arm, and when the adjustment angle reaches approximately 90 degrees, valve plate 33 also It is swiveled through 90 degrees to the solid line position and lies flat in the passage of the passing fluid, opening the flow cross-section of the valve body 31.

During this time, the distance between the pins b and a is kept constant throughout.

34, 35, 39 are brackets.

In the above conventional type, fluid pressure is applied to the valve plate 33 when the valve is closed.
When opening this valve from a state in which it is acting, the valve plate 33
Therefore, there is a problem in that the load torque applied to the valve shaft 38 via the drive arm 36 increases.

This will be explained in detail with reference to FIG. 6, in which the length of the drive arm 36 is smaller than the length of the sunk 30.

That is, when the length of the drive arm 36' is made shorter than the link 30', as the drive arm 36' pivots from the chain line position in the valve opening direction, the link 30' changes the distance between pins a and b to a constant length t. You can turn while keeping the

Then, it turns at solid line position 1, but after that, the distance between the locus of pin a of drive arm 36' and the locus of pin b of link 30' becomes larger than the above-mentioned t, so link 3
0' cannot be turned any further and the valve cannot be opened any further.

As described above, in the conventional type, as long as the drive arm is placed closer to the valve plate than the link, it cannot be made smaller than the link.

Since the link is involved in the pivoting movement of the valve plate, there is a limit to how short it can be made.

Therefore, the drive arm has to become longer in relation to the link, and the longer the drive arm, the greater the load torque.

Regardless of whether it is a link or a drive arm, the valve plate can be rotated by lengthening the one on the valve plate side, so by making the link on the valve plate side, the drive arm can be rotated as much as possible. However, in this case, the link comes into contact with the valve shaft, that is, the pivot axis of the drive arm, and therefore cannot pivot sufficiently.

Therefore, the technical problem of this invention is to make the drive arm as short as possible by arranging the link on the valve plate side, and to enable the link to rotate sufficiently without coming into contact with the valve shaft.

The technical measures taken to solve the above technical problems are:
The other end of the link is pivotally connected via a horizontal pin b to a bracket placed at the center of the back of the valve plate between pin a of the drive arm and the valve plate, and the link is shaped like a dogleg. The drive arm is curved in the opposite direction to the plate, and the length of the drive arm is made shorter than the link, and when fully closed, pin C and pin B
The line connecting the valve stem and pin a should be located closer to the valve plate and almost parallel to the line connecting the valve stem and pin a.

The operation of the above technical means is as follows.

In other words, when the valve is closed, the line connecting pins C and B of the link is closer to the valve plate than the valve stem, but since the link is curved in an almost dogleg shape, the link straddles the valve stem. , on the opposite side of the valve plate relative to the valve stem.

Therefore, during the valve opening operation, the link pivots in a direction away from the valve stem, and does not come into contact with the valve stem, allowing the link to pivot sufficiently to fully open the valve.

To change the face valve plate from the fully open state to the fully closed state, perform the operation in the opposite manner to the above.

This invention produces the following unique effects.

When the valve receives heat and undergoes thermal deformation, the difference between the amount of thermal distortion of the link and the amount of thermal distortion of the drive arm is determined by a line connecting pins B and C that can be applied to the nearly doglegged curved part of the link. By absorbing displacement in the direction that intersects with
The relative distance from the line connecting the link and the drive arm can be varied, reducing the internal stress generated in the link and the drive arm, making the valve opening and closing smoother, and ensuring the valve is closed.

Examples of this invention will be described below.

In FIGS. 1 and 2, 1 is a valve box, and a valve seat 16 is provided on one side of the valve box.

A valve plate 2 is rotatably provided in the valve box 1 so that a valve seat 20 provided on the outer peripheral edge of the valve plate 2 can come into contact with a valve seat 16 of the valve box.

A bracket 7 is provided at the center of the back surface of the valve plate 2, and one end of the bracket 7 is pivotally connected via a horizontal pin C to a bracket 8 of a holder 17 provided on the upper part of the valve box. The other end of the link 3 curved in the opposite direction is the horizontal pin b
It is pivotally connected via.

A rotary valve shaft 5 is horizontally disposed in the valve box 1 between the link 3 and the valve plate 2 and slightly above the horizontal pin b, with both ends supported by bearings 9. A pulley 15 is connected to one end of the shaft by a reducer 10.
It is designed to be driven through.

11 is a bushing, 12 is a backing, and 13 is a backing presser.

One end of a pair of left and right drive arms 4, 4 is fixed to the twisted valve shaft 5, and the other ends of the arms 4, 4 are on the same horizontal plane as the horizontal pin b, and are connected to the horizontal pin with respect to the valve plate 2. It is pivotally connected via a horizontal pin a to a bracket 6 which is located rearward of b and slightly higher than bracket 7 on the side of the valve plate 2 relative to the vertical plane passing through the axis of the valve shaft 5.

14 is a drain pipe. Next, the operation of the above embodiment will be explained.

To open the valve plate 2, the valve shaft 5 is rotated by a speed reducer 10, and the drive arms 4, 4 having one end fixed to the valve shaft 5, are gradually rotated.

Then, the valve plate 2 attached to the other end of the drive arm 4.4
initially separates the valve body valve seat 20 almost vertically from the valve body valve seat 16 while being supported by the link 3, and then begins to pivot downward about an axis parallel to the valve seat 16, until the valve body 9
When it rotates 0 degrees, it is in a fully open state flat with the flow path (3rd
figure).

On the other hand, when the valve shaft 5 is rotated in the opposite direction from this state, the drive arms 4, 4 gradually rotate in the reverse direction, and the valve plate 2 starts to rotate upward, and when the rotation approaches 90 degrees, the valve body valve seat 20 The valve body moves vertically toward the valve seat 16 and comes into contact with it, and is in a fully closed state (FIGS. 1 and 2).

At this time, the valve body valve seat 20 overlaps and comes into close contact with the valve body valve seat 16, so that the flow of fluid flowing through the flow path is completely blocked.

FIG. 4 shows another embodiment of this invention, in which the horizontal pin of the link 3 is installed by attaching the receiver 17 to the upper part of the valve body 1 via the stud 18 and the upper and lower nuts 19. The position of C can be finely adjusted up and down.

If such a receiver 17 is used, it is possible to mount the horizontal pin C at the desired setting position even if there is an accuracy error during manufacturing and assembly.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view showing an embodiment of this invention, Fig. 2 is a partial longitudinal sectional side view of the same as above, Fig. 3 is a longitudinal sectional side view explaining the operation, and Fig. 4 is another embodiment of this invention. FIGS. 5 and 6 are longitudinal sectional side views of the conventional device. 1-... Valve box, 2... Valve plate, 3...
...Link, 4゜4... Drive arm, 5...
...Valve stem, a, b, c horizontal pins.

Claims (1)

[Scope of utility model registration request] One end of the drive arm is fixed to a rotary valve shaft installed horizontally in the valve box, and the other end of the drive arm is attached via a horizontal pin a to a bracket arranged in approximately the same horizontal plane as the center of the back of the valve plate. One end of a link having a different length from the driving arm is pivotally connected to the inner wall of the valve box via a horizontal pin C, and the other end of this link serves as a parallel link mechanism that cooperates with the driving arm. In a butterfly valve connected to a plate, the other end of the link is pivoted between pin a of the drive arm and the valve plate and pivoted to a bracket placed at the center of the back of the valve plate via a horizontal pin b, The link is curved in a substantially dogleg shape in the opposite direction to the valve plate, and the length of the drive arm is made shorter than the link, and the line connecting pin C and pin b when fully closed is connected to the valve shaft and pin a. A butterfly valve characterized by being located on the valve plate side and almost parallel to the line connecting the lines.