JPH0720462Y2 - Valve body opening / closing device - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve body opening / closing device for a valve in which the valve body is opened and closed by reciprocally rotating the valve stem.

[0002]

2. Description of the Related Art A driven body which is integral with a valve stem, for example, a pinion, is provided on both sides thereof with a fluid pressure cylinder and a spring pressure cylinder which are coaxial with each other. A valve body opening / closing device that engages with the driven body is well known.

In this structure, the valve rod is opened and closed by rotating the valve stem forward and backward by pushing and moving the operating rod in the forward and reverse directions with the fluid pressure and the spring.

[0004]

The above-mentioned conventional device has the following problems.

(A) Since the spring has a large load difference between the mounted state and the compressed state, there is an output loss.

(B) The piston operated by fluid pressure is
It is necessary to overcome the force required to rotate the valve body and the force to compress the spring, and a large actuation force is required.

(C) Since the spring pressure cylinder is long in order to produce a required stroke, the entire apparatus becomes large and heavy.

[0008]

In a valve body opening / closing device in which a valve stem is rotated by a forward movement of a piston housed in a fluid pressure cylinder, the fluid pressure cylinder is removed when the pressure in the fluid pressure cylinder is removed. A guide cylinder whose outer end is separated from an end wall of the cylinder is provided in the gas pressure cylinder provided so as to face the fluid pressure cylinder, and the guide cylinder is urged by the gas pressure in the gas pressure cylinder therein. A push rod for pressing the inner piston in the opposite direction is provided, and an airtight flexible diaphragm is stretched between the outer end of the guide tube and the push rod therein.

[0009]

When the fluid pressure cylinder is depressurized, the gas pressure in the gas pressure cylinder pushes the pushing rod in the fluid pressure cylinder in the opposite direction.

[0010]

1 shows an embodiment of the present invention. A fluid pressure cylinder (4) and a gas pressure cylinder (5) are coaxially arranged on both sides of a housing (3) which houses a valve stem (1) and a pinion (2) which is integral with the valve stem.

The fluid pressure cylinder (4) houses a piston (7) which is integral with a rack rod (6) which meshes with the pinion (2). On the outer end wall (8) of the fluid pressure cylinder (4), there is provided a pressure fluid supply / discharge port (9) which is usually compressed air.

The gas pressure cylinder (5) is a fluid pressure cylinder.
A guide tube (11) is formed on the boundary wall (10) between the housing (3) and the gas pressure cylinder (5) and has a diameter larger than that of the guide tube (11). The outer end of the guide tube (11) is a gas pressure cylinder.
It is slightly separated from the outer end wall (12) of (5).

Inside the guide tube (11), there are a push rod (13) whose inner end abuts against the tip of the rack rod (6), and a pressure receiving rod (15) whose outer end face (14) is formed in an arc shape. An integral piston (16) is housed. The push rod (13) and the rack rod (6) may be integrally formed.

Between the peripheral edge of the piston (16) and the outer end of the guide tube (11), there is an airtight flexible diaphragm (1) which can expand and contract in the axial direction.
7), for example, a bellows is stretched. The through hole (18) of the pushing rod (13) in the boundary wall (10) is sealed by an O-ring (19).

A liquefied gas or air having a required pressure is enclosed in the gas pressure cylinder (5) for use. Supply and discharge port
In the return process with (9) opened, the gas pressure cylinder
The gas pressure acting on the portion of the piston (16) surrounded by the airtight flexible diaphragm (17) and the conical surface of the tip of the pressure receiving rod (15) through the pushing rod (13). The rack rod (6) is actuated in the return direction, and the valve stem (1) is rotated in the reverse direction.

In the above embodiment, the rack rod (6) and the pinion are used.
Although the valve stem (1) is rotated by (2), the present invention is also applied to the one in which a pin protruding laterally from the piston rod is engaged with a fork that is integral with the valve stem. sell. In some cases, the pushing rod (13) does not include the piston (16), and the inner end of the airtight flexible diaphragm (17) is directly attached to the pushing rod (13).

[0017]

Advantages of the Invention (a) The gas pressure cylinder can be remarkably shorter in length as compared with the conventional one provided with a spring cylinder for reverse operation, and the size of the apparatus can be reduced. (b) Since the compression spring does not exist and the gas pressure cylinder is short, the weight can be reduced. (c) Since there is no compression spring, there is no need to use a special tool for disassembly or assembly, and there is no danger of harm due to the repulsive force of the compression spring. (d) Unlike the compression spring, the pressing force does not decrease at the end of the stroke, and the operation is performed with a constant force.
Definitely done.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing an embodiment of the present invention.

[Explanation of symbols]

(1) Valve stem (2) Pinion (3) Housing (4) Fluid pressure cylinder (5) Gas pressure cylinder (6) Rack rod (7) Piston (8) Outer end wall (9) Supply / discharge port (10) Boundary Wall (11) Guide tube (12) Outer end wall (13) Push rod (14) Outer end face (15) Pressure receiving rod (16) Piston (17) Airtight flexible diaphragm (18) Through hole (19) O-ring

Claims (1)

[Scope of utility model registration request] 1. A valve body opening / closing device in which a valve stem is rotated by a forward movement of a piston housed in a fluid pressure cylinder, the valve body opening / closing device facing the fluid pressure cylinder when the pressure in the fluid pressure cylinder is removed. A guide cylinder whose outer end is separated from the end wall of the cylinder is provided in the provided gas pressure cylinder, and the piston in the fluid pressure cylinder is biased therein by the gas pressure in the gas pressure cylinder. A valve body opening / closing device provided with a pushing rod for pressing in the opposite direction, and further comprising an airtight flexible diaphragm stretched between the outer end of the guide cylinder and the pushing rod therein.