JP2504870B2 - Valve drive - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive unit for opening and closing a valve, and more specifically, it applies a resilient repulsive force of a compression spring or a working fluid pressure to a valve shaft via a piston to close a diaphragm valve. The present invention relates to the improvement of the valve drive section that holds the state.

[0002]

2. Description of the Related Art A valve drive unit is known in which a valve shaft is connected to a piston provided in a cylinder so as to be reciprocally movable directly or via a transmission mechanism, and the piston is reciprocated to open and close the valve. A known valve drive unit, in which a compression spring is arranged between a cylinder cap or spring receiver and a piston, opens the valve by pushing up the piston with the working fluid pressure, releases the working fluid pressure, and repels the compression spring. Close the valve by lowering the piston. When the valve is closed, the compression spring expands and its elastic repulsion force is minimized, but the minimum elastic repulsion force holds the valve closed against the pressure of the fluid in the valve that tries to open the valve. A known valve drive unit that can introduce pressure air to both sides of the piston is to introduce pressure air to the upper side and discharge the pressure air from the lower side to close the valve, and then close the valve with the thrust of the pressure air. Hold.

[0003]

When the fluid working pressure of the valve is increased, the force by which the fluid tries to open the valve is increased when the valve is fully closed. Therefore, the valve closing holding force must be increased. For this reason, when the elastic repulsive force of the compression spring of the valve drive unit or the working fluid pressure is increased, the valve drive unit is correspondingly made large and sturdy. This large and robust valve drive is expensive and poses the problem of constraining the installation space. Moreover, this runs counter to the demand for smaller valves.

The present invention has been made to solve these problems, and an object of the present invention is to provide a valve drive unit having a valve closing holding force larger than that of a conventional valve drive unit. To do.

[0005]

In order to achieve the above object, the means adopted by the present invention is a body including a cylinder,
A valve including a piston reciprocally inserted in the cylinder, a valve shaft that reciprocates together with the piston but is axially movable within a predetermined range, and a drive unit that reciprocates the piston. In the drive unit, the lever is mounted inside the cylinder, and the thrust of the piston is enlarged and transmitted to the valve shaft through the lever.

[0006]

The valve using the compression spring is, as described above,
By the minimum elastic repulsion force of the compression spring acting on the piston,
A valve that does not use a compression spring presses the valve shaft by the thrust of the working fluid pressure acting on the piston to hold the valve closed, but at this time, the piston and valve shaft can slide to each other in the axial direction to some extent. Yes, the piston pushes the valve shaft further downward, that is, in the direction of closing the valve, via the lever. As a result, the elastic repulsive force of the compression spring or the thrust of the working fluid pressure acting on the piston is expanded by the lever, which becomes the valve closing holding force, so that only the minimum elastic repulsive force or the working fluid pressure of the conventional compression spring is applied. The valve closing force is significantly increased as compared with the one that was dependent on. Therefore, if the size of the compression spring or the working fluid pressure is the same as the conventional one, that is, if the size of the valve drive unit is the same as the conventional one, the usable fluid pressure becomes higher and the working fluid pressure becomes If the same, smaller compression springs or working fluid pressures can be used, i.e. the valve drive can be made smaller.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A valve drive unit according to the present invention will be specifically described based on the embodiments shown in the drawings. The embodiment of FIGS. 1 and 2 is a diaphragm valve that opens and closes the valve with air. The valve includes a valve body 10 having a flow passage 11 and a valve seat 12 that divides the flow passage 11 therein, a diaphragm 20 that covers an upper opening of the valve seat 12, and a bonnet that tightly fixes the periphery of the diaphragm to the valve body 10. A cylinder 31 integrated with the valve shaft 15, a valve shaft 15 whose lower end is locked to the center of the upper surface of the diaphragm 20 via a compressor 16, a cap 33 connected and fixed to the upper surface of the cylinder 31, and a valve shaft 15
A nut 13 and a flange 14 that are fitted to the piston, a piston 40 that is fitted so as to be slidable in the axial direction between the nut and the flange, and an O-ring 41 provided on the outer peripheral surface of the piston.
With. The cylinder 31 and the cap 33 are the main body of the valve drive unit.
Forming 30. Bolt the base 54 on the inner bottom surface of the cylinder 31.
Mounted by 55, lever 50 through pin 53 to its lever
Lock the shaft. Roll 51 through pin 52 at the top of the lever
Lock the shaft. When the piston 40 reaches the lower limit position, the roll 51 abuts the conical lower surface of the piston 40 and the lever projection 56
Contacts the step 17 of the valve shaft 15. Pin that serves as the fulcrum of lever 50
The distance from 53 to the contact point between roll 51 and piston 40 is pin 53
Since it is set to be 2 to 3 times the distance from the projection 56 to the contact point of the step portion 17, the thrust of the piston 40 is expanded by 2 to 3 times and acts on the valve shaft 15.

As shown in FIG. 3, when pressurized air is introduced from the lower inlet / outlet port 43 of the cylinder 31 and the upper inlet / outlet port 45 is released, the piston 40 moves to the upper limit position and the valve shaft 15 via the nut 13. Push up to open the valve. At this time, the lever 50 is the valve shaft
It falls to the side by the step 17 of 15. As shown in Figure 1,
When the lower inlet / outlet port 43 is opened and pressurized air is introduced from the upper inlet / outlet port 45, the piston 40 descends and pushes down the valve shaft 15 via the flange 14. At this time, the conical lower surface of the piston 40 comes into contact with the roll 51 of the lever 50 to raise the lever. Lever 50
When standing up, its protrusion 56 abuts the step portion 17 of the valve shaft 15,
The thrust of the piston 40 is enlarged and transmitted to the valve shaft 15.

The embodiment shown in FIGS. 4 and 5 is a diaphragm valve in which the valve is opened by air pressure and closed by a compression spring. Cylinder 31
Inside, the compression spring 45 is arranged between the upper surface of the piston 40 and the lower surface of the spring receiver 44, and the configuration is the same as the above embodiment except that the pressure air inlet / outlet 43 is provided only on the lower side of the piston 40. Is. On the inner bottom surface of the cylinder 31, the lever 54 is attached to the base 54.
The lever 50 is fixed via the pin 50, and the lever 50 is pivotally mounted on the lever base via the pin 53. A roll 51 is pivotally attached to the upper end of the lever 50 via a pin 52.

As shown in FIG. 5, when pressurized air is introduced from the inlet / outlet 43, the piston 40 pushes up the valve shaft 15 via the nut 13, and the diaphragm 20 separates from the valve seat 12, so that the flow passage 11
The open valve opens. As shown in FIG. 6, the valve opening is 100%
When, the compression spring is compressed and the elastic repulsion force is 20
It becomes 0 Kgf. When the compressed air is discharged, the compression spring 45 pushes the piston 40 downward together with the valve shaft 15 as shown in FIG.
Since the diaphragm 20 is in close contact with the valve seat 12, the valve is closed.
As shown in FIG. 6, when the valve is fully closed, the elastic repulsive force of the compression spring reaches a minimum of 100 kgf, but the conical lower surface of the piston 40 contacts the roll 51 and the projection 56 contacts the step portion 17. Therefore, the thrust exerted by the compression spring 45 on the valve shaft 15 is enlarged by a factor of 2 to 3 to 200 to 300 Kgf,
The valve is maintained in the closed state by the expanded thrust, that is, the valve closing holding force. When the compression spring is enlarged and the same valve closing holding force is obtained without using the lever 50, the cylinder and the cap have the sizes shown by the chain line in FIG.

Although the diaphragm valve is shown as an example,
The present invention is not limited to the diaphragm valve, and can be applied to all valves including a valve drive unit that reciprocates a piston to open and close the valve.

[0012]

As described above, the valve drive unit of the present invention has the compression spring acting on the piston when the valve is closed or the lever for expanding the thrust of the working fluid pressure and transmitting it to the valve shaft. Alternatively, unlike the case where the thrust of the working fluid pressure is transmitted to the valve shaft as it is, the valve closing holding force is significantly increased.
Therefore, the valve drive unit of the present invention can have a higher fluid use pressure if the size is the same as the conventional one, and the valve drive unit can be made smaller if the fluid use pressure is the same. It has the excellent effect of being able to

[Brief description of drawings]

FIG. 1 is a front view of a diaphragm valve having a valve drive unit according to an embodiment of the present invention, and a cross section of the right half shows a state in which the valve is closed.

2 is a sectional view taken along the line BB of FIG.

3 is a diagram showing a state where the valve of FIG. 1 is opened,

FIG. 4 is a diagram corresponding to FIG. 1 of another embodiment,

FIG. 5 is a diagram corresponding to FIG.

6 is a graph showing the thrust acting on the valve shaft of the embodiment of FIG.

[Explanation of symbols]

 13: Nut 14: Flange 15: Valve shaft 17: Step portion 30: Body 31: Cylinder 40: Piston 50: Lever 51: Roll (one end) 53: Pin 54: Lever base 56: Protrusion (other end)

Claims (1)

(57) [Claims] 1. A body (30) including a cylinder (31) and a piston (40) reciprocally slidably inserted in the cylinder.
And a valve shaft (15) reciprocally provided with the piston.
And driving means (43, 44, for sliding the piston back and forth)
45) in a valve drive part, wherein a nut (13) and a flange (14) are fixed to the valve shaft, and the piston is attached to the valve shaft so as to be slidable between the nut and the flange. When the lever (50) is pivotally attached to the inner bottom portion of the cylinder and the piston comes to the valve closed position, one end (51) of the lever engages with the lower surface of the piston and the other end (56). Is engaged with a stepped portion (17) of the valve shaft to increase the thrust of the piston and transmit the thrust to the valve shaft.