JPS5937385A - Driving device of valve - Google Patents

Abstract

PURPOSE:To obtain a lightweight, small-sized and inexpensive driving device of a valve by increasing the open/close stroke of the valve without changing the length of the isometric link or the shift stroke. CONSTITUTION:When a handle 22 is rotated clockwise, shift members 17, 17' are shifted so as to approach together due to the screwing relation between male thread sections 20, 20' and female thread sections 16, 16' with different thread directions. Pantographs A, B are extended, a valve bar 7 is moved downward, and the valve port 3 is closed by a valve body 2. VS=nVdcotalpha where, alpha is an angle formed by a line parallel to the axis of a drive shaft 19 and a link 14 at a pin 8, (n) is the number of steps of all links, Vd is the speed of the shift members 17, 17', and VS is the speed of the valve bar 7. As the shift members 17, 17' approach together, alpha is gradually increased and VS is decreased, thereby the valve body slowly closes the valve port 3 near the close position of the valve and the water hammer is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a valve driving device used for gate valves, globe valves, and the like.

In general, when the valve is closed, in the drive device for the seed valve,
Without changing the drive speed from fully open to fully closed, the closing speed of the valve near the closed position is slowed down to prevent water hammer due to sudden closing, and to counter the increase in fluid resistance near the closed position when fully opened or closed. It is desirable that the closing force increases with the same driving force as at the intermediate opening. Conventional techniques to solve this problem include, for example, U.S. Patent No. 4,285,
The one shown in the specification of No. 493 is known. However, in the above method, the lower ends of a pair of equal-length links are pivoted to the upper end of the valve stem, and the upper ends of the equal-length links are moved toward or away from each other by a driving member to raise and lower the valve stem. Therefore, in order to increase the opening/closing stroke of the valve, which is approximately the same as the travel stroke of one of the links, the length and travel stroke of the link must be increased, and therefore the drive device must be large. This method has drawbacks such as being expensive and requiring a large installation space for the valve.

The present invention eliminates the drawbacks of the conventional devices described above, and provides a lightweight, compact, and inexpensive valve drive device that can increase the opening and closing stroke of the valve while maintaining the length and movement stroke of the equal-length link. purpose.

In order to achieve the above object, a valve driving device according to the present invention includes a valve stem having one end connected to a valve body that opens and closes a valve port in a valve box, and one end of each being pivoted to the other end of the valve stem. a pair of first equal-length links; and, separately from this, at least one link whose intermediate portion is pivoted symmetrically on the axis of the valve stem;
and a pair of second isometric links, this twenty-fourth! Each one end of the long link is pivoted to each other end of the first equal length link so as to form a cross-section, and each other end of the second equal length link is moved toward or away from each other. The pantograph is characterized in that it includes a drive member that gives telescopic movement to the pantograph.

The illustrated embodiment will be described below.

The figure shows an example of implementation on a gate valve, where 1 is a valve box, 2 is a valve port 3
A valve body that opens and closes, 4 is an upper lid, 5 is a stand fixed on the upper lid 4, 6 is a left and right half-shaped case fixed on the stand 5, and 7 is a lower end connected to the valve body 2. With the valve stem,
The lower ends of a pair of equal-length links 8, 8' are pivotally supported via pins 9 in front and behind the upper end of the valve stem 7, which passes through the upper cover 4 and is located inside the stand 5. Each upper end of the equal-length links 8, 8' has a length twice that of the links 8, 8', and their midpoints are symmetrically supported via a pin 10 on the axis of the valve stem 7. The lower ends of the pair of equal length links 11 and 11' are pivotally supported via a pin 12 so as to form a pantograph A. Further, at the upper ends of each of the equal-length links 11 and 11', there is a pair of equal-length links 1 having the same structure as the links 11 and 11', whose midpoints are pivotally supported via a pin 13.
4 and 14' are similarly pivoted via pins 15 so as to form a zonagraph B. Each upper end of the equal length links 14, 14' has a female threaded portion 16, 16'.
The lower ends of a pair of moving members 17.1'l' each having a movable member 17.1'l' installed therein are pivotally supported via a pin 18.

The female threaded portions 16 and 16' are provided with male threaded portions 20. provided on both sides of the drive shaft 190 facing each other with different twisting directions.
20' are screwed together. One end of the drive shaft 19 passes through the case cover 21 and projects to the outside of the case 6, and an operating handle 22 is fixed to this projecting end. Therefore, when the nozzle 22 is rotated, the moving members 17, 1
7' is moved toward or away from each other on the drive shaft 19, and this moving force is transmitted to the valve stem 7 via the graphs A and B. That is, when the movable members 17 and 17' approach each other, the nozzles A and B extend and move the valve stem 7 downward in the direction in which the valve body 2 closes the valve port 3, and conversely, the movable members 17 and 17 1 when ' moves away from each other. The e-tagraphs A and B are contracted and the valve stem 7 is raised in the direction in which the valve body 2 opens the valve port 3.

Reference numeral 24 denotes a bushing which is divided into left and right halves, has a slit on the side facing the valve opening, and is installed inside the case 6, and is a bushing which is connected to the movable member 17.
, 17' serve as a traveling guide that also serves as a rotation stopper when moving, and also receives a load 5- in the axial direction of the valve rod 7 acting on the moving members 17, 17'. A pair of kite grooves 25 are installed in the front and rear walls of the stand 5, and when the pantographs A and B expand and contract, the kite grooves 9, 10, and 13 are engaged to prevent the pantographs A and B from twisting. It is prevented. Also 26
27 is a packing holder, and 27 is a packing presser.

Next, the operation of the above embodiment will be explained.

The valve open state in FIG. 2, that is, the moving members 17, 17
' moves away from the maximum phase on the drive shaft 19, and the pantograph A
, B, when closing the valve from the minimum contracted state, for example, when the handle 22 is rotated clockwise, the moving member 17
, 17' is a male screw part 20.20 with a different twist direction.
Due to the threaded engagement between the female threaded portions 16 and 16', the /e intergraph A is moved toward each other by this moving force.

Since B is extended as shown in FIG. 1 and the valve stem 7 is lowered, the valve port 3 is closed by the valve body 2. The force relationship at this time is as shown in FIG.
The force (moving force) given by 17' is F, the angle formed by the link 14 and a line parallel to the axis of the drive shaft 19 in the bin 8 is α, the link 8,
When the height of 8′ is one step, the total number of steps n (=
5) If the downward force acting on the valve stem 7 is P, then the velocity of the moving members 17 and 17' is Vd.

If the speed of the valve stem 7 is 1, then Va = nVdcotα=5Vdcotα...
......(2), F and Vd are constant, n =
5. In the case of α near 5° to 15°, it becomes as shown in FIG. That is, as the moving members 17 and 17' approach each other, α gradually increases, so when F is constant (1)
From the equation, P increases to accommodate the fluid resistance R that increases as the valve closes, and v8 also increases as α increases (2)
Since it decreases according to the formula, the valve body 2 gently closes the valve port 3 near the valve closing position, and water hammer is prevented.

Next, when opening the valve, when the handle 22 is rotated counterclockwise, the moving members 17 and 17' are moved away from each other, and this moving force retracts the pantographs A and B, and the valve rod 7 is raised, so the valve port 3 is opened. At this time, the force relationship K is opposite to that in the case of closing, and the upward force (opening force) P acting on the valve stem 7 is initially thick (
, becomes smaller as the valve is opened, and the speed VB of the valve stem 7 is slow at first, but becomes faster as the valve is opened.

FIG. 5 shows another embodiment of the present invention, in which a fluid pressure cylinder 31 is slidably fitted into a case 32 via a bush 33, and a rod fixed to a piston 34 of the cylinder 31. A movable member 36 is fixed to the tip of the rod 35, and a movable member 36' is fixed to the end surface of the cylinder 31 facing the movable member 36 so that the rod 35 can move. In the above, when pressure fluid is supplied to the boat 37 of the cylinder 31, the piston 34 moves to the boat 38 side of the cylinder 31, and accordingly, the moving member 36 is moved to the moving member 36' via the rod 35.
The moving member 36' is moved closer to the cylinder 31.
and moves closer to the moving member 36,
Pantographs A and B are extended and the valves are closed. Conversely, when pressure fluid is supplied to the boat 38, the piston 34
moves toward the boat 37 and moves the movable members 36 and 36' away from each other, so that the pantographs A and B are retracted and the valves are opened. The configuration of other parts is the same as that of the previous embodiment, so the same parts are given the same reference numerals and the explanation will be omitted.

In addition, in the above embodiment, the pantograph with multiple links is
The height of the links 8.8', which are arranged in series and pivoted on the valve stem 7, is 1
Although the number of tiered links is shown as 5, it is not limited to this, and one pantograph may be installed in a row to form a 3-tier configuration, or 3 pantographs may be installed in a row. It goes without saying that the number of stages of the link can be selected as appropriate depending on the opening/closing stroke of the valve.

In addition, although the equal length links 11, 11' and 14, 14' are configured to have twice the length of the equal length links 8, 8',
It may be different from double, and it may be an equal length link]
1, 11' and 14, 14' may also have slightly different lengths, and the detailed design can be changed as appropriate.

Since this invention is configured as described above, the opening/closing stroke of the valve can be made thicker while keeping the length of the first equal-length link and the moving stroke the same.Therefore, the device itself is small and well-balanced with the valve body. In addition to being lightweight and economical, it does not require a large installation space.Furthermore, the valve can be closed near the closed position without changing the drive speed from fully open to fully open when closing the valve. Slow speed to prevent water hammer due to sudden closure,
Moreover, it has excellent effects such as increasing the closing force with the same driving force as when the opening is fully open or at an intermediate opening, against an increase in fluid resistance near the closing position.

[Brief explanation of drawings]

Fig. 1 is a partially vertical 10-front view showing one embodiment of the present invention, Fig. 2 is a partially vertical side view of the same, Fig. 3 is an enlarged sectional view of the main parts of the same, and Fig. 4 is a partial longitudinal sectional view of the same. FIG. 5 is an enlarged sectional view of a main part showing another embodiment of the present invention. 1... Valve box 2... Valve body 3...
Valve port 7... Valve rod 8.8'... Equal length link 11.11', 14, 14'... Equal length link 9.10, 12, 13, 15.18... Bin 17
．． 17', 36.36'... Moving member 19... Drive shaft 31... Cylinder A, B... Pantograph Figures 3 and 4

Claims (1)

[Claims] 1. A valve stem with one end connected to a valve body that opens and closes a valve port in a valve box, and 1 with each end pivoted to the other end of this valve stem.
a pair of first equal length links; and at least one pair of second equal length links whose intermediate portions are pivoted symmetrically on the @ line of the valve stem; Each one end of the equal length link is pivoted to each other end of the first equal length link so as to form a cross section, and each other end of the second equal length link is moved toward or away from each other. A driving device for a valve, comprising a driving member that gives telescoping motion to the pantograph.