JPH10160032A - Control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily adjust elastic force of an elastic member, and enable operation in a narrow space by arranging an elastic holding member slidably with an inner surface of a cylinder case, an air introduction port for providing initial elastic force, and a screw for fixing the position of the holding member. SOLUTION: A piston-like spring pressor (holding member) 20 is slidably formed along an inner surface of a cylinder case 6, while airtightly dividing a space inside the cylinder case 6. An air introduction port 21 is formed for introducing air so as to provide a spring 9 with initial elastic force. In order to provide the spring with the initial elastic force, high pressure air is introduced from the air introduction port 21, the holding member 20 is pressed down against the elasticity of the spring 9, and it is compressed until it has the initial elastic force. A screw 8 is turned downward in such a state to fix the holding member 20. It is therefore possible to avoid difficulty such as fastening the screw 8 by the use of a large-sized tool, and easily provide initial elastic force even when a valve arrangement space is narrow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control valve for controlling a flow rate of a fluid by opening and closing a plug by driving an operating device.

[0002]

2. Description of the Related Art FIGS. 2A and 2B are partial sectional views showing a conventional control valve, wherein FIG. 2A shows an upper portion other than a valve box 13, and FIG.
3 is shown. In the drawing, 1 is a plug as a valve for controlling the flow rate of a fluid to be passed, 2 is a valve shaft for transmitting a driving force to the plug 1, 3 is a stem shaft connected to the valve shaft 2 by a stem connector 4, Reference numeral 5 denotes a piston which is connected to the stem shaft 3 and reciprocates up and down in the cylinder case 6, reference numeral 7 denotes an upper portion of the cylinder case, reference numeral 8 denotes a screw screwed to the upper portion of the cylinder case 7, and reference numeral 9 denotes the piston 5 in a downward direction in the figure. A biasing spring, 10 is a spring retainer, 11 is an air inlet / outlet for taking air in and out of a space below the piston in the cylinder case 6, 12
Is a yoke for connecting and fixing the cylinder case 6 and the valve box 13, 13 is a valve box, and 14 is a valve seat.

Next, the operation will be described. A downward biasing pressure is constantly applied to the upper surface of the piston 5 by a spring 9, and the downward biasing pressure applied to the piston 5 causes the plug 1 to move downward through the stem shaft 3 and the valve shaft 2. Energized, thereby closing the valve.

[0004] The lower surface of the piston 5 also has an air inlet / outlet 11.
From the compressed air, receives an upward biasing pressure due to air pressure, and this upward biasing pressure biases the plug 1 upward through the stem shaft 3 and the valve shaft 2, whereby the valve is actuated. open.

During operation of the control valve, by adjusting the air pressure supplied from the air inlet / outlet 11, the balance between the downward urging pressure by the spring 9 and the upward urging pressure by the air pressure changes. As a result, the plug 1 moves up and down to adjust the gap between the plug 1 and the valve seat 14, and the flow rate of the fluid is controlled.

In an initial state in which no air pressure is applied from the air inlet / outlet 11 and no upward urging pressure is applied, the plug 1 is completely closed by the downward urging pressure of the spring 9 and no fluid leakage occurs. Need to be. In order to generate the initial pressure on the plug 1 in this manner, the spring 9 needs to have an initial elastic force in a state where the spring 9 is sufficiently compressed from its natural length. Then, the screw 8 is tightened to lower the position of the spring retainer 10 so that the natural length spring 9 is sufficiently compressed.

The conventional example shown in FIG. 2 is a reverse-acting control valve in which when air is introduced from the air inlet / outlet 11, the piston 5 rises and the plug 1 rises.
Although an initial elastic force is applied to the spring 9 in order to completely close the plug 1 in the initial state where no air pressure is applied from the air and to prevent the fluid from leaking, the structure of the actuator of the conventional control valve is the same as that of the prior art. In the case of a positive-acting control valve that is overturned, that is, a positive-acting control valve in which the piston descends and the plug descends when air is introduced from the air inlet / outlet, the initial state in which air pressure from the air inlet / outlet is not applied In this case, an initial elastic force is applied to the spring so that the plug is completely opened and the fluid completely flows.

[0008]

Since the conventional control valve is configured as described above, in order to sufficiently generate the initial pressure by the spring 9, the screw 8 is tightened at the time of assembling and the spring retainer 10 is set. To the compression side,
The spring 9 had to be sufficiently compressed. The initial elastic force applied by the compression of the spring 9 is about 2 tons depending on the use of the control valve. To rotate the screw 8 holding the initial elastic force, an extremely large torque of about 30 kg torque is required. It is necessary, and even when the screw 8 is rotated by an extra-large spanner, it is necessary to turn the screw 8 with a strong force. Therefore, there is a problem that a space for a spring tightening operation is required around the control valve in which a plurality of pipes and the like are arranged, and in order to perform assembling and maintenance, the screw 8 is generally strong in a narrow space. There is a problem that it is necessary to perform an extremely difficult operation of rotating the spring 9 between the natural length and the initial length by rotating it by force.

Also, when adjusting the position of the spring holder 10 by moving the position of the spring retainer 10 to change the elastic force of the spring 9, since the elastic force of the spring 9 is always applied to the screw 8, the screw 8 is There is a problem that a large torque is required for rotation, and the operation is difficult similarly to the above.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and the elastic force of an elastic member such as a spring 9 can be easily adjusted. It is an object of the present invention to obtain a control valve that can be easily operated in the above-described manner.

[0011]

According to a first aspect of the present invention, there is provided a control valve which is formed so that a space in a cylinder case is hermetically sealed and slidable along the inner surface of the cylinder case. A holding member for holding the elastic member from the opposite side, and air can be applied from outside by introducing air from outside into a space on the side where the elastic member is not disposed among the spaces in the cylinder case defined by the holding member. And a holding member position fixing means for fixing the holding position of the holding member.

In the control valve according to the second aspect of the present invention, in the initial state in which the urging pressure of the air is not applied to the pressure member, the plug is completely closed to prevent the fluid from leaking. The elastic member is provided so as to be slidable by compressing the elastic member to a position at which an initial elastic force required for completely opening the fluid to completely flow the fluid is applied to the elastic member.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a partial cross-sectional view showing a control valve according to Embodiment 1 of the present invention. In the drawing, reference numeral 1 denotes a plug as a valve for controlling a flow rate of a fluid to be passed;
Reference numeral 2 denotes a valve shaft for transmitting a driving force to the plug 1, reference numeral 3 denotes a stem shaft connected to the valve shaft 2 by a stem connector 4 (a shaft connected to the plug), and reference numeral 5 denotes a stem shaft 3,
A piston (pressure member) reciprocating up and down in the cylinder case 6, 7 is an upper portion of the cylinder case, 8 is a screw (holding member position fixing means) screwed to the upper portion 7 of the cylinder case, and 9 is a piston 5. A spring (elastic member) for urging in a downward direction, an air inlet / outlet 11 for taking air in and out of a space below the piston in the cylinder case 6,
Reference numeral 12 denotes a yoke for connecting and fixing the cylinder case 6 and the valve box 13, reference numeral 13 denotes a valve box, and reference numeral 14 denotes a valve seat, which are the same as those of the conventional control valve shown in FIG.

The control valve of the conventional example shown in FIG. 2 is slightly different from the control valve of the first embodiment in the structure of the lift stopper for preventing the piston 5 from rising excessively. A control valve of a type in which a lift stopper is formed by using a cylinder case 6 having two portions having different diameters as the cylinder case 6. The control valve in FIG. This type of control valve constitutes a lift stopper by sharply cutting only the section to be reciprocated and adjusting the diameter of the piston 5 to this section, but this difference is not related to the gist of the present invention.

Numeral 20 denotes a piston-shaped spring retainer (holding member), which is different from the conventional spring retainer 10 in that the diameter thereof is adjusted to the inner diameter of the cylinder case 6 so as to be slidable along the inner surface of the cylinder case 6. The space inside the cylinder case 6 is airtightly partitioned. Reference numeral 21 denotes an initial compression air introduction port (air introduction port) into which air is introduced when an initial elastic force is applied to the spring 9, and 22 is above the piston 5 in the cylinder case 6 and below the piston-like spring retainer 20. This is an air hole that allows air to freely enter and exit the space.

Next, the operation will be described. A downward biasing pressure is constantly applied to the upper surface of the piston 5 by a spring 9, and the downward biasing pressure applied to the piston 5 is:
The plug 1 is urged downward via the stem shaft 3 and the valve shaft 2, whereby the valve is in a closed state. The lower surface of the piston 5 also receives an upward biasing pressure by air pressure by flowing compressed air through the air inlet / outlet 11, and the upward biasing pressure is applied to the plug 1 via the stem shaft 3 and the valve shaft 2. Urges upward, which causes the valve to open. During the operation of the control valve, by adjusting the air pressure supplied from the air inlet / outlet 11, the balance between the downward urging pressure by the spring 9 and the upward urging pressure by the air pressure changes. The gap between the plug 1 and the valve seat 14 is adjusted by moving the plug 1 up and down, and the flow rate of the fluid is controlled.

In an initial state in which no air pressure is applied from the air inlet / outlet 11 and no upward biasing pressure is applied, the plug 1 is completely closed by the downward biasing pressure of the spring 9 and no fluid leaks. Although it is necessary, the work of applying the initial elastic force of the spring 9 which is the source of the initial pressure to the plug 1 is performed as follows, unlike the conventional example.

First, a high-pressure air source such as instrumentation air generally arranged in a plant or the like is connected to the initial compression air introduction port 21 through a pressure reducing valve or the like, and the high-pressure air is introduced into the initial compression air introduction port. It is introduced through the mouth 21. As a result, the piston-shaped spring retainer 20 is lowered against the elasticity of the spring 9, and the spring 9 is compressed to a state having a predetermined initial elastic force. Then, in this state, the screw 8 is rotated and lowered to fix the piston-shaped spring retainer 20.

At this time, the force for rotating the screw 8 is
Since the elastic force of the spring 9 is not directly applied to the spring, an extremely small force is sufficient, and there is no need to perform an operation of tightening the screw 8 with a large force using a large spanner or the like as in the related art.

When the spring 9 adjusts the elastic force exerted on the piston 5 more strongly, high-pressure air is introduced from the initial compression air introduction port 21 to further lower the position of the piston-like spring retainer 20, so that In this state, rotate the screw 8 to lower it, and
Fixation.

When the elastic force applied by the spring 9 to the piston 5 is weakly adjusted, the screw 8 may be loosened as it is. However, high-pressure air is introduced from the initial compression air inlet 21 to hold down the piston-like spring. The position of 20 is lowered slightly so that the elastic force of the spring 9 is not applied to the screw 8. In this state, the screw 8 is rotated and raised, and then the introduction of high-pressure air from the initial compression air introduction port 21 is stopped. Preferably, the piston-like spring retainer 20 is raised to be fixed by the screw 8.

In the adjustment of the elastic force of the spring 9, the screw 8 can be rotated in any case without the elastic force of the spring 9 being applied to the screw 8 when the screw 8 is raised or lowered. The force for rotating the screw 8 is extremely small.

As described above, according to the first embodiment, the spring 9 can be compressed to have an initial elastic force by using high-pressure air such as instrumentation air generally usable in a plant or the like. It is not necessary to perform a difficult operation such as tightening the screw 8 with a large force using a large tool such as a large spanner, and the initial elastic force can be easily applied to the spring 9 even when the installation place of the control valve is small. And a control valve can be installed.

Also, when adjusting the strength of the elastic force of the spring 9, the screw 8 can be turned up and down by rotating the screw 8 in a state where the elastic force of the spring 9 is not directly applied to the screw 8. Work such as adjustment of the elastic force of the spring 9 can be easily performed without requiring a large work space.

In the above description, the control valve using the piston 5 as the elastic member and the pulsating member receiving the urging pressure by the air pressure is shown on both surfaces. However, another pulsating member such as a diaphragm is used as the pulsating member. In the control valve used,
It is needless to say that the present invention can be applied to a control valve having an elastic member other than the spring 9 as the elastic member. Also,
As the holding member position fixing means for fixing the piston-like spring retainer 20, a fixing means of a type other than the screw 8 may be used as long as the fixing means can be fixed. It goes without saying that a position fixing means may be provided.

In the above description, an example is shown in which the present invention is applied to a reverse-acting control valve in which the piston 5 rises and the plug 1 rises when air is introduced from the air inlet / outlet 11, but the present invention is not limited to this. Can also be applied to a positive-acting type control valve in which the piston 5 descends and the plug 1 descends when air is introduced from the air inlet / outlet 11, and almost every part of the operation device shown in FIG. It is needless to say that a holding member position fixing means such as a screw 8 may be similarly provided in a bonnet portion on the lower surface of the cylinder case 6 so as not to interfere with the stem shaft 3. Nor.

[0027]

As described above, according to the first aspect of the present invention, the space inside the cylinder case is airtightly divided so as to be slidable along the inner surface of the cylinder case. A holding member that holds an elastic member from the opposite side, and air is introduced from outside into a space on the side where the elastic member is not disposed, of the space in the cylinder case defined by the holding member so that air pressure can be applied. Since it is configured to include the provided air introduction port and the holding member position fixing means for fixing the holding position of the holding member, adjustment of the elastic force of the elastic member for applying the urging pressure to the pressing member, etc. The air pressure is introduced from the air inlet by eliminating the need to rotate the screw with the elastic force of the elastic member directly by a large tool such as a large spanner as in the conventional control valve. hand There is an effect that can be easily carried out by fixing the elastic force and the holding member securing means is moved to the target position the position of the holding member under the balance of sex member. Therefore, there is an effect that work such as adjustment of the elastic force of the elastic member of the adjustment valve can be easily performed even in a small installation place without requiring a large tool as in the related art.

According to the second aspect of the present invention, in the initial state in which the urging pressure of the air is not applied to the pressure member, the plug is completely closed and no fluid leakage occurs or the plug is completely closed. The elastic member is configured to be slidably provided by compressing the elastic member to a position where the elastic member is opened and the initial elastic force necessary for the fluid to flow completely is applied to the elastic member. The operation of applying an initial elastic force to the elastic member in a type control valve,
As in the conventional control valve, there is no need to rotate the screw to which the elastic force of the elastic member is directly applied by a large tool such as a large spanner with a large force, and the air pressure is introduced from the air inlet to the holding member so that the holding member can be rotated. By moving the position against the elastic force of the elastic member and fixing the position by fixing the holding member, there is an effect that the operation can be easily performed. Therefore, there is an effect that it is not necessary to use a large tool as in the related art, and it is possible to easily apply the initial elastic force to the elastic member and install the control valve even in a narrow installation place.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a control valve according to Embodiment 1 of the present invention.

FIG. 2 is a partially sectional side view showing a conventional control valve;
(A) shows the upper part other than the valve box, and (b) shows the part of the valve box.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plug 3 Stem shaft (shaft connected to a plug) 5 Piston (compression member) 6 Cylinder case 8 Screw (holding member position fixing means) 9 Spring (elastic member) 20 Piston spring retainer (holding member) 21 Air for initial compression Inlet (air inlet)

Claims (2)

[Claims] 1. A plug connected to a shaft connected to a plug. One surface receives an urging pressure by an elastic member, and the other surface receives an urging pressure by air pressure to reciprocate in a cylinder case and drive to the plug. A pressure transmitting member for transmitting a force, and a space in the cylinder case is airtightly formed so as to be slidable along an inner surface of the cylinder case, and holds the elastic member from the opposite side of the pressure member. A holding member, and an air introduction port provided so that air can be applied from outside to a space on the side where the elastic member is not disposed, of the space in the cylinder case defined by the holding member, and an air pressure can be applied, And a holding member position fixing means for fixing a holding position of the holding member. 2. The holding member, in an initial state in which no pneumatic biasing pressure is applied to the pressure member, in a state in which the plug is completely closed and no fluid leaks, or in a state where the plug is completely opened and the fluid flows completely. 2. The control valve according to claim 1, wherein the elastic member is slidable by compressing the elastic member to a position at which an initial elastic force necessary for attaining a state is applied to the elastic member.