JP2002156068A - Driving device for butterfly valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving device of a valve capable of closing a valve while reducing a rotating speed of a valve rod connected to a cylinder without lowering the cutoff torque just before the closing of the valve, being operated by single working pressure, and dispensing with accessories and a control mechanism mounted on the external of the cylinder. SOLUTION: A depressurizing piston provided with a slit having a contraction part is mounted on a pressure chamber partition of a single-acting cylinder device for driving the valve rod, and opening and closing the valve element in a state that it can come into and out of the pressure chamber, the depressurizing piston is projected into the pressure chamber to quickly discharge the air from the slit in closing the valve, and the air is discharged from the contraction part of the slit just before the closing of the valve, whereby the movement of the depressurizing piston is decelerated, and simultaneously the movement of a valve driving piston abutted on the depressurizing piston is decelerated to decelerate the rotation in the valve closing direction of the valve element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butterfly valve driving device, and more particularly to a butterfly valve driving device capable of changing a speed at the time of closing a valve body.

[0002]

2. Description of the Related Art Conventionally, it has been known to control the opening and closing of a line by attaching a butterfly valve to a pipeline through which various fluids flow, and to rapidly shut off or open the flow passage depending on the fluid in the pipeline. It is required that the valve be closed rapidly in the event of a disaster or an emergency such as an accident to minimize damage. In such a case, a single-acting high-speed cylinder device that does not require a power source is frequently used as a valve driving device. Furthermore, in recent years, there has been a demand for accurate control of the flow rate with a butterfly valve. In such a case, a single-acting high-speed cylinder device is used as a driving device. However, when the valve element is driven using a single-acting high-speed cylinder device, the valve element is suddenly pressed against the valve seat surface to close the valve seat, so that the valve seat is easily damaged and there is a problem in durability. Therefore, in order to reduce the valve speed immediately before closing the valve and to protect the valve seat, a single-acting cylinder device having a mechanism for gradually changing the speed until the valve closes has been proposed, For example, it is disclosed in Japanese Patent Publication No. 59-5191.

A valve closing speed control device disclosed in Japanese Patent Publication No. 59-5191 discloses a valve closing speed control device in which a piston rod end of a single-acting cylinder device connected to a valve shaft is closed just before the valve closes. The single-acting cylinder is actuated according to the moving speed of the hydraulic cylinder by contacting the rod. However, such a valve closing speed control device has a structure in which a single-acting cylinder device connected to a valve shaft operates pneumatically, whereas a hydraulic cylinder that controls the speed of the single-acting cylinder device is a hydraulic cylinder. It is a structure that operates with hydraulic pressure such as, requires accessories and a control mechanism outside the single-acting cylinder device, requires two types of cylinder devices with different pressure sources, complicates the mechanism, Since an operating pressure source must be prepared and various operating devices such as a switching valve and a flow control valve must be prepared corresponding to a plurality of operating pressures, there is a disadvantage that the cost is increased and the control is complicated.

[0004]

SUMMARY OF THE INVENTION The present invention enables the valve to be closed without reducing the closing torque while reducing the rotational speed of the valve stem connected to the cylinder immediately before the valve is closed. An object of the present invention is to provide a valve driving device that can operate at a single operating pressure and does not require any accessories or a control mechanism outside the cylinder.

[0005]

In order to solve the above-mentioned problems, the present invention employs a flow-contracting device in a pressurizing chamber partition of a single-acting cylinder device which drives a valve rod to open and close a valve body. A pressure-releasing piston having a slit formed therein is provided so as to be able to freely enter and exit the pressurized chamber, and when the valve is closed, the pressure-releasing piston is protruded into the pressure chamber to rapidly exhaust the gas from the slit. So that the movement of the depressurizing piston is decelerated, and at the same time, the movement of the valve driving piston in contact with the depressurizing piston is decelerated to reduce the rotation of the valve body in the valve closing direction. It is characterized by having done.

A spring is provided on the depressurizing piston so as to always project toward the pressurizing chamber, and a valve returning piston is connected to one end of the valve driving piston.
The valve return piston is provided with a spring which constantly urges in the return direction, and the spring force of the spring is greater than the spring force of the spring provided on the pressure release piston.

[0007] The valve return piston is characterized in that a stopper pin for limiting the amount of movement is freely abuttable.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below. The present invention provides a depressurizing piston formed with a slit having a contraction portion in a pressurizing chamber partition of a single-acting cylinder device that opens and closes a valve body by driving a valve rod, and the pressurizing chamber for closing a valve. When the pressure is released, the decompression piston is protruded into the pressurized chamber by the spring force of the spring, and the exhaust port is opened. Move the piston in the valve closing direction. And immediately before closing the valve,
By causing exhaust from the contraction part of the slit,
The movement of the depressurizing piston is decelerated, the movement of the valve driving piston in contact with the depressurizing piston is decelerated, and the rotation of the valve body in the valve closing direction is decelerated and slowly rotated. Features. When the valve driving piston is pressurized in the valve opening direction, the depressurizing piston is urged by the pressure in the pressurizing chamber in a direction to close the exhaust port, and the pressure in the pressurizing chamber is not discharged. Also, when the valve is driven in the valve closing direction from the fully open position, the pressure in the pressurizing chamber is discharged,
The depressurizing piston projects into the pressurizing chamber by the spring force of the spring, and is rapidly exhausted through the slit of the depressurizing piston, so that the pressure in the pressurizing chamber rapidly decreases and the valve rapidly changes until immediately before closing. It is turned. Immediately before closing the valve, resistance to pressure discharge is exerted by the contraction portion of the slit, rotation of the valve is decelerated, and rapid closing of the valve is avoided, so that damage to the valve seat due to collision with the valve body is prevented. I can do it.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, (1) is a valve stem of a rotary valve having a rotating valve element such as a butterfly valve, and is attached to a driving piston rod (3) of a single-acting cylinder device (2). Arm (4)
And is rotated by the operation of the single-acting cylinder device. One end of the drive piston rod (3) is connected to a drive piston (6) disposed in the drive cylinder (5), and the other end is a return cylinder (7).
Connected to a return piston (8) disposed therein. A depressurizing piston (10) having a slit is provided in a partition (9) of the driving cylinder (5), and the depressurizing piston (10) is provided.
Is slidably housed in the cylinder (12) while being urged by the small spring (11) so as to always project toward the driving piston (6). An exhaust port (13) is formed in the cylinder (12), and a switching valve (15) is provided via a check valve (14).
Linked to A slit (16) having a contraction portion (17) as shown in FIGS. 2 and 3 is formed in the depressurizing piston (10), and the air in the pressurizing chamber (18) of the single-acting cylinder is formed. It can be discharged from the slit (16) and the contraction part (17)
In this case, the amount of discharge is reduced to act as resistance.

The pressurizing chamber (19) of the return cylinder (7)
Is connected to the pressurizing chamber (18) of the drive cylinder (5), and when the drive piston (6) is driven, the return piston (8) is simultaneously operated in the same direction.
In (8), a large spring (20) is stretched, and a stopper pin (21) for setting a working distance is provided. The large spring (20) has a greater resilient force than the small spring (11) stretched over the decompression piston (10), and when returning, against the small spring (11), the decompression piston (10). ) Is returned to the exhaust stop position.

Referring to FIG. 1, the figure shows a fully closed state of the valve body. In this state, when the switching valve (15) is switched to the left port in the figure, the air pressure passes through the check valve (22). The driving piston (6) flows into the left side of the driving piston (6), that is, into the pressurizing chamber (18), and the driving piston (6) moves rightward in the drawing. When the driving piston (6) moves rightward, the driving piston rod (3) moves rightward, and the valve stem (1) connected by the arm (4) is driven and rotated in the valve opening direction. The valve is opened as shown in FIG. Since the pressurizing chamber (19) of the return piston (8) connected to the pressurizing chamber (18) of the driving piston (6) is also pressurized, the piston (8) compresses the large spring (20). While moving to the right, until it comes into contact with the stopper pin (21), and becomes the fully open state in FIG. In this fully open state, the pressurizing chamber
Due to the pressure in (18), the depressurizing piston (10) is in a non-operating state in which it does not project into the pressurizing chamber (18) as shown in FIG.
The pressurized air in the pressurized chamber (18) is not discharged.

In order to rotate the valve element in the valve closing direction from the fully opened state, first, as shown in FIG. 5, the port of the switching valve (15) is switched to stop the supply of air pressure, and at the same time, the pressurizing chamber (18) The inside is communicated with the atmosphere via a throttle valve (23) to exhaust air. Since the pressure in the pressurizing chamber (18) decreases due to the start of evacuation, the depressurizing piston (10) is resiliently pressed by the small spring (11).
Into the pressurizing chamber (1
8) The air pressure inside is discharged quickly. With the discharge of the air pressure in the pressurizing chamber, the driving piston (6) rapidly moves to the left in the drawing, and the valve stem connected to the piston rod (3).
(1) is rotated in the valve closing direction. Immediately before closing the valve, the driving piston (6) comes into contact with the decompression piston (10), and the decompression piston (10) is pushed into the partition (9) by the elastic force of the large spring (20). With the movement of the pressure release piston (10), the slit (16) is closed and only the contraction portion (17) is opened, so resistance to air pressure discharge occurs and the drive piston
The movement of (6) is decelerated, and the deceleration of the piston is transmitted to the valve stem (1) via the piston rod (3), and the rotation of the valve stem is slowed down, and the valve element is moved at a slow speed immediately before closing the valve. Close the valve by contacting the valve seat. Therefore, the valve body and the seat ring do not suddenly come into contact with each other, and the seat ring can be prevented from being damaged. In this case, there is no change in the operating torque of the driving piston (6), and the valve closing torque of the valve rod (1) rotated via the piston rod (3) does not decrease.

[0013]

According to the present invention, since the operation of the driving piston is decelerated immediately before the valve is closed, abrupt contact between the valve body and the valve seat is avoided, and the durability of the valve seat is reduced. And a longer life can be achieved. Also, the valve can be opened without deceleration when operating from the valve-closing position to the valve-opening position, and can be decelerated only when opening and closing the valve. Further, by replacing the partition wall of the existing single-acting cylinder with a partition wall having a depressurizing piston, it can be changed to a drive device having an opening / closing speed variable function according to the present invention. It is.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing the structure of the present invention;
Shows valve-closed position

FIG. 2 is a cross-sectional view schematically showing an enlarged main part.

FIG. 3 is a perspective view of a depressurizing piston.

FIG. 4 is a sectional view similar to FIG. 1, showing a state during valve opening;

FIG. 5 is a cross-sectional view similar to FIG. 1 in a state where the valve is switched from a valve-open position to a valve-closed position;

[Explanation of symbols]

 (1) Valve stem (2) Single acting cylinder device (3) Driving piston rod (4) Arm (5) Driving cylinder (6) Driving piston (7) Return cylinder (8) Return piston (9 ) Partition wall (10) Depressurizing piston (11) Small spring (12) Cylinder (13) Exhaust port (14) Check valve (15) Switching valve (16) Slit (17) Shrinkage part (18) Pressurizing chamber ( 19) Pressurizing chamber (20) Large spring (21) Stopper pin (22) Check valve (23) Throttle valve

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16K 31/42 F16K 31/42 A F term (Reference) 3H055 AA02 AA13 AA22 GG13 JJ11 JJ14 3H056 AA04 BB02 BB04 BB08 BB24 CA03 CB03 CC05 CC12 CD04 CE01 DD05 DD08 DD09 EE08 3H081 AA03 AA25 BB03 BB14 CC15 DD37 HH05

Claims (4)

[Claims] 1. A depressurizing piston having a slit having a contraction portion is provided in a pressurizing chamber partition of a single-acting cylinder device for driving a valve rod to open and close a valve body so as to freely enter and exit the pressurizing chamber. When the valve is closed, the depressurizing piston is projected into the pressurized chamber to quickly exhaust air from the slit, and immediately before closing the valve, the exhaust is performed from the contraction portion of the slit to slow down the movement of the depressurizing piston and simultaneously release the air. A butterfly valve driving device, wherein a movement of a valve driving piston abutting on a pressure piston is decelerated to reduce a rotation of a valve body in a valve closing direction. 2. The driving device according to claim 1, wherein a spring is stretched on the depressurizing piston so as to always protrude toward the pressurizing chamber. 3. A valve-returning piston is connected to one end of the valve-driving piston, and a spring that constantly urges the valve-returning piston in a returning direction is stretched, and the spring force of the spring is released. 3. The driving device according to claim 2, wherein the driving force is greater than the elastic force of a spring stretched over the pressure piston. 4. The drive device according to claim 3, wherein a stopper pin for limiting the amount of movement of the valve return piston is freely abuttable.