JP3142304B2 - Controller with seal breakage detection mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller provided with a seal failure detecting mechanism, and a purpose thereof is to allow fluid flowing into the controller from a flow passage of the controller to leak outside due to breakage of a seal in the controller. It is an object of the present invention to provide a controller with a seal portion breakage detection mechanism that detects this immediately when a failure occurs.

[0002]

2. Description of the Related Art In a chemical plant, the flow rate of raw materials and fuel, the magnitude of pressure, the height of liquid level, the temperature, etc. are measured and are always controlled to constant values. Is provided. The flow rate in this chemical plant,
The pressure and the like are all adjusted by the flow rate of the fluid, and in the present chemical industry, almost a pneumatic diaphragm control valve is used as a valve used for the flow rate adjustment.

[0003] The diaphragm valve has, for example, the structure shown in FIG. 11. This diaphragm valve consists of a handle (a), valve stem (b), diaphragm holder (c), diaphragm (d), valve body (e), bonnet
(f), bonnet presser (g), spring (h), body (i)
Is the main configuration.

To close the valve, turning the handle (a) lowers the valve stem (b) and deforms the diaphragm (d) by pressing the valve stem (b). It descends against (h) and closes channel (j). To open the valve,
Turn the handle (a) in the opposite direction to raise the valve stem (b). Then, the valve body is actuated by the spring force of the spring (h).
(e) also rises, the flow path (j) is opened, and the diaphragm (d) returns to its original shape by the pressure of the valve body (e).

In the example shown in FIG. 11, the valve is in an open state, and the fluid flowing in the pipe also flows into the spring housing space (l) in the body (i). This fluid is normally shielded by the diaphragm (d),
does not flow out of (i).

[0006] However, the diaphragm (d) may cause fatigue due to long-term use, or foreign matter caught in opening and closing.
If it is damaged for any reason, fluid will leak from that area. Leaked fluid is bonnet (f) and bonnet retainer (g)
Or leaks out through a leak check hole (m) (indicated by a broken line) formed in the bonnet retainer (g).

[0007] Such leakage not only hinders the normal circulation of the fluid, but also can lead to a serious accident in the case of a chemical plant that handles dangerous substances such as toxic gas and flammable gas. It is a danger. Therefore, when the above-mentioned fluid leakage occurs, it is necessary to detect the leakage immediately and replace the damaged part. Conventionally, such a means for detecting the fluid leakage from the control valve is, for example, a plant. A method of monitoring a leak from the control valve by attaching a leak sound detection sensor for detecting a leak sound from the control valve to the section has been used. Alternatively, only measures such as a double structure of the control valve (diaphragm) have been adopted for the control valve itself.

[0008]

However, the above-mentioned prior art has the following problems. When installing a leak sound detection sensor in a part of the plant, the sensor detects the sound due to the jet stream of the fluid ejected from the gap between the valves, so that the leak sound of the leaked fluid is detected by the sensor. If it is not spread, it will not be detected,
There was a problem that the damaged portion could not be found at the same time as the valve was damaged. On the other hand, when the diaphragm valve has a double structure, there is a problem that if the first-stage diaphragm is broken, it cannot be recognized. Although these conventional techniques are effective means for detecting breakage of the seal portion of the controller, they lack the immediacy, and therefore, the industry has developed a controller which can detect breakage of the seal portion (diaphragm) of the controller in a very short time. Creation was desired.

[0009]

SUMMARY OF THE INVENTION The present invention provides a seal breakage detection system comprising a hole formed on an outer surface of a controller for controlling a flow rate of a fluid, and a leak detection member attached to the hole to detect leakage of the fluid. A controller with a mechanism, wherein the hole communicates with a gap in the controller, the leak detection member is responsive to the presence of a specific fluid, and the hole communicates with a leak detection member attached to the outside. By providing a controller with a seal portion breakage detecting mechanism characterized by the above, all of the above-mentioned conventional disadvantages are eliminated.

[0010]

The fluid leaks out of the seal portion due to the breakage of the seal portion in the controller or the intrusion of foreign matter into the seal portion, and when the fluid fills the gap in the controller, the fluid flows into the hole formed in the outer surface of the controller. Also filled with fluid. The presence of the fluid flowing into the hole sensitizes the leak detection member attached to the hole.
If the leak detection member is a fluid sensing sensor, this sensor senses the presence of fluid and communicates this to the signal generator,
The breakage of the seal portion can be detected by the signal from the signal generator. If the leak detection member is discolored by contact with a specific fluid, the breakage of the seal portion can be easily detected by visually observing the discoloration of the leak detection member.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a controller with a seal portion damage detection mechanism according to the present invention will be described below with reference to the drawings.

In FIG. 1, (1) shows a diaphragm valve which is a controller in which the present invention has been developed. This diaphragm valve (1) has a handle (2) as described in the description of the prior art.
, Valve stem (3), Diaphragm presser (4), Diaphragm (5)
, A valve body (6), a bonnet (7), a bonnet retainer (8), a spring (9), and a body (10). Channel
As described above, the opening and closing of (11) is performed by moving the valve (6) up and down by operating the handle (2). O-rings (28) and (29) are interposed between the body (10) and the bonnet presser (8) and between the bonnet (7) and the valve stem (3). The outer surface of the diaphragm valve (1), in this embodiment, a bonnet presser
On the outer surface of (8), a hole (13) communicating with the gap (12) in the diaphragm valve (1) is formed, and on the inner periphery of the hole (13), a female screw (1) is formed.
3a) is formed. A leak detection member (14) is attached to the hole (13). Hereinafter, each embodiment of the leak detecting member (14) will be described with reference to FIGS.

FIG. 2 shows a leak detecting member (14) according to the present invention.
Of the first embodiment is shown. In the first embodiment shown in the drawing, a pair of upper and lower covering members (15) which are screwed with female screws (13a) of the holes (13) are provided, and the leakage detecting members (14) are provided in the covering members (15). Is installed. In the present invention, the leak detecting member (14) is not particularly limited, and any material such as a sensor or a discoloring substance can be suitably used as long as it is sensitive to the presence of a specific fluid.

FIG. 3 shows a leak detecting member (14) according to the present invention.
Is shown in the second embodiment. In the second embodiment shown in the drawing, a fluid sensor is provided as a leak detecting member (14) in the cover (15), and the fluid sensor (14) is electrically connected to a signal generator (16) outside the controller. Communication.

In the present invention, the fluid sensing sensor (14) is not particularly limited, and may be any sensor that is sensitive to the presence of a specific fluid. An example of the fluid sensor (14) is a catalytic combustion type gas sensor (141) as shown in FIG.

The structure of the sensor element (141a) of the catalytic combustion type gas sensor (141) is not particularly limited. For example, a platinum wire coil (141a-2) is formed of a catalyst in which platinum or palladium is supported on alumina shown in FIG. ) May be covered and baked at a high temperature of about 1000 ° C. Connect this sensor element (141a) to 3
When heated to 00 to 400 ° C. and an electric current is applied to the platinum wire coil (141a-2), when a fuel gas such as methane comes into contact, combustion occurs by a catalytic action. Therefore, the sensor element (141
a) The temperature of the internal platinum wire coil (141a-2) increases, and the electrical resistance increases. On the other hand, the electric resistance of the coil does not change on the compensating element that does not support the noble metal catalyst. Therefore, when the sensor element (141a) and the compensating element are combined, a voltage difference occurs in the electric circuit, and the fuel gas can be detected by measuring the voltage difference.

This catalytic combustion type gas sensor (141) is hardly affected by ambient temperature and humidity, and has high accuracy and excellent reproducibility, so that it is suitable for use in a plant such as petrochemical industry. .

In the present invention, as the fluid sensing sensor (14), in addition to the above-described catalytic combustion type gas sensor (141), a metal oxide semiconductor type gas sensor (142) shown in FIG. 6 can be exemplified as a preferred embodiment.

The metal oxide semiconductor type sensor element (142a) is a metal oxide semiconductor as shown in FIG. 7 of the gas sensor (142), the tin oxide is particularly n- type semiconductor (S _n O ₂₎ sintered body ( 142a-1) is sandwiched between a pair of platinum-based alloy wire coils (142a-2), and the periphery of the coil is covered with the same semiconductor material. A voltage is applied to one of the coils (142a-2) so that it also serves as a heater, and the sintered body is further passed through two coils.
The sintered body (142a-1) is heated to about 350 ° C by Joule heat generated by applying a current to (142a-1). When the heated sintered body (142a-1) adsorbs flammable gas such as hydrogen, alcohol, methane, etc., the electron concentration on the surface of the sintered body (142a-1) increases. ) The resistance of itself drops sharply. The flammable gas can be detected from the change in the electric resistance.

The change in the electrical resistance of the tin oxide (S _n O ₂₎ sintered body (142a-1) is different degrees depending on the type of the temperature and the combustible gas of the sintered body. For example, easily oxidizable gases such as hydrogen, carbon monoxide, and alcohol are
42a-1) The sensitivity becomes maximum at the temperature, but the sensitivity becomes maximum at the temperature of the sintered body (142a-1) of 500 ° C. or more for methane and isobutane. The same applies to the type of sintered body. For example, a sintered body of zinc oxide other than tin oxide (SnO ₂ ) has high sensitivity to ethyl alcohol, while iron- Tin composite oxides (eg, ferric oxide (2-FeO ₃ , hematite)) show high sensitivity to propane and isobutane.
As described above, it is possible to selectively detect a specific gas component by changing the temperature of the sintered body itself or changing the type of the sintered body.

The metal oxide semiconductor type gas sensor (142) as described above is excellent in long-term stability and durability, and is sensitive to aging even if it changes with time. Suitable for mechanisms.

In addition to the catalytic combustion type gas sensor (141) and the metal oxide semiconductor type gas sensor (142), two electrodes (A
Known sensors such as a galvanic cell type sensor (143) composed of (b), (Ac), a diaphragm (B) and an electrolyte (C) (see FIG. 8) and a potentiostatic electrolytic type sensor are also suitable for the present invention. Used for In addition, a constant potential electrolytic sensor, an Augusta sensor, a gas heat conduction sensor, and the like can all be suitably used.

In the second embodiment, the fluid sensor (14) senses the presence of a fluid filled in the space of the controller (1) and transmits a signal to the signal generator (16), A predetermined signal is transmitted from the generator 16 (for example, see FIG. 9). Therefore, the breakage of the seal portion can be detected at a location away from the controller (diaphragm valve).

Next, a third embodiment of the seal breakage detecting mechanism of the controller according to the present invention will be described. In the third embodiment shown in FIG. 10, the leak detecting member (14) is a fluid detecting tube (142) and is inserted into the covering (15). This fluid detection tube (1
42) is filled with a color changing agent (142-a) which changes color when it comes into contact with a specific fluid. The color-changing agent (142-a) is a substance in which a color-changing substance is coated on the surface of an inorganic carrier particle, and the color-changing substance is colored or decolorized upon contact with a specific fluid. Any one is suitably used as long as it is not particularly limited. This discoloration can be caused by reaction with the chemical components of the fluid or by changes in pH and moisture content. As an example of this, for example, those having a property of discoloring due to a change in pH, such as methyl red and bromthymol blue, are exemplified. In the third embodiment, when the seal portion of the controller (diaphragm valve) (1) is damaged and fluid leaks from the damaged portion, the leaked fluid is removed from the gap in the controller (1).
It fills (12) and flows into the fluid detection tube (142) through a hole (13) formed on the outer surface of the controller (1). Fluid sensing tube
When the discoloring agent (142-a) in (142) comes into contact with the fluid flowing into the fluid detection tube (142), the discoloring agent is discolored and the discolored agent is discolored.
Visual inspection of (142-a) makes it possible to easily detect breakage of the seal portion.

In each of the above-described embodiments, the hole (13) formed on the outer surface of the controller (diaphragm valve (1)) is used as a leak check hole in a commercialization process before mounting the leak detecting member (14). The hole (13)
A defective product can be checked based on whether a fluid is allowed to flow in from the flow path and the fluid is detected from the flow path (11). Further, in the first and second embodiments, the leak sensor can be promptly dealt with by connecting the leak detection sensor (14) to a monitor or alarm system by wiring.

[0026]

As described above in detail, the present invention relates to a seal portion comprising a hole formed on an outer surface of a controller for controlling a flow rate of a fluid, and a leak detecting member attached to the hole to detect a leak of the fluid. A controller with a damage detection mechanism, wherein the hole communicates with a gap in the controller, the leak detection member is responsive to the presence of a specific fluid, and the hole is externally mounted with the leak detection member attached. Since the controller is provided with a seal portion damage detection mechanism, the controller has the following effects. That is, when the fluid from the flow path of the controller flows out due to breakage of the seal portion in the controller,
A leak detection member is sensitive to the presence of the escaping fluid. Therefore, the breakage of the seal portion in the controller can be easily and promptly detected. In the present invention, when the fluid handled by the plant is a poisonous gas or a flammable gas, the dangerous gas flows out of the hole provided with the leak detection member. Therefore, in such a case, it is natural that sufficient care must be taken to prevent a person from approaching the hazardous gas that has leaked to the outside or to cause ignition from the hazardous gas.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a controller in which a controller with a seal portion damage detection mechanism according to the present invention appears.

FIG. 2 is an enlarged sectional explanatory view showing one embodiment of a controller with a seal portion damage detection mechanism according to the present invention.

FIG. 3 is an enlarged sectional explanatory view showing one embodiment of the present invention.

FIG. 4 is an explanatory view of a catalytic combustion type gas sensor which is an embodiment of the fluid detection sensor which is the leak detection member.

FIG. 5 is an enlarged view of a sensor element of the catalytic combustion type gas sensor shown in FIG.

FIG. 6 is a structural explanatory view of a sensor element of a metal oxide semiconductor type gas sensor which is an embodiment of a fluid detection sensor which is a leak detection member of the controller with the seal portion damage detection mechanism according to the present invention.

7 is an explanatory view of a sintered body of the sensor element shown in FIG.

FIG. 8 is a structural explanatory view of a galvanic cell type sensor which is an embodiment of a fluid detection sensor which is a leak detection member of the controller with a seal portion damage detection mechanism according to the present invention.

FIG. 9 is an enlarged cross-sectional explanatory view showing one embodiment of a signal generator used in the controller with a seal portion damage detection mechanism according to the present invention.

FIG. 10 is an enlarged sectional explanatory view showing an embodiment of a controller with a seal portion damage detection mechanism according to the present invention.

FIG. 11 is a partial sectional explanatory view showing an example of a conventional controller.

[Explanation of symbols]

 1 Controller (diaphragm valve) 12 Air gap 13 Hole 14 Leak detection member 15 Coating 16 Signal generator

Continuation of the front page (56) References JP-A-51-107184 (JP, A) JP-A-61-50032 (JP, A) JP-A-60-108725 (JP, A) JP-A-2-140341 (JP) U.S. Pat. No. 4,901,751 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01M 3/04

Claims (3)

(57) [Claims] 1. A hole formed on an outer surface of a controller for controlling a flow rate of a fluid, and the hole is attached to the hole to detect leakage of the fluid.
A leak detecting member including a leak detecting member, wherein the hole communicates with a gap in the controller, the leak detecting member is responsive to the presence of a specific fluid, and the hole detects a leak. A controller with a seal portion breakage detection mechanism, wherein the controller is connected to the outside with the detection member attached. 2. The leak detection member is a fluid sensor, which is mounted in a hole on the outer surface of the controller and is electrically connected to a signal generator outside the controller. 2. The controller with a seal portion breakage detecting mechanism according to claim 1, wherein the controller detects the presence of a fluid filled in the gap in the controller and transmits a signal to the signal generator. 3. The controller with a seal portion damage detection mechanism according to claim 1, wherein the color of the leak detection member is changed by contact with a specific fluid.