JPH06331142A - Gas shutting-off device - Google Patents

Abstract

PURPOSE:To provide a gas shutting-off device not causing any explosion of gas even in the case that a gas having a characteristic of ignition is leaked from its bomb. CONSTITUTION:A gas sensor 5 detects that a gas is leaked from a bomb 2 and a gas leakage signal is fed out to a control panel 10A, resulting in that before a shutting-off valve 2a of the bomb 2 is closed in response to a signal got from the control panel 10A, the releasing valve 9a of a replacement bomb 9 installed outside a cylinder cabinet 1A is opened in response to a signal got from the control panel 10A as well, an inert gas is discharged into the cylinder cabinet 1A so as to replace with gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas shutoff device, and more particularly to a gas shutoff device which prevents gas explosion even if gas leak is stopped when gas leak is detected.

[0002]

2. Description of the Related Art FIG. 3 is a schematic block diagram partially showing a conventional gas shutoff device. In the figure, 1 is a housing box, for example, a cylinder cabinet. A container such as a cylinder 2 is placed in the cylinder cabinet 1. The cylinder 2 is filled with a raw material gas for manufacturing a semiconductor, an optical fiber, or the like, for example, a special material gas such as monosilane, phosphine, arsine, or diborane.
It should be noted that these gases have the property of spontaneous ignition that easily ignites in the air, and self-decomposition that causes a rapid pressure increase due to the chain decomposition of the gas in the air. It also has the property of being corrosive. For this reason, great care is taken in handling this gas, and the cylinder 2 filled with gas is placed in the cylinder cabinet 1 as described above and is isolated from the atmosphere. Further, the cylinder 2 is provided with a shutoff valve 2a (also referred to as a pneumatic valve) that closes the main valve of the cylinder 2 by being opened / closed by a remote operation described later, and a gas to a destination such as a factory through the shutoff valve 2a. A supply pipe 2b is provided.

On the ceiling of the cylinder cabinet 1, a gas detector for detecting a gas leak, for example, a silane sensor, is provided with an exhaust duct 3 for taking in air from the outside and exhausting a gas leaked inside, a ventilation fan 4 and the like. 5 are provided.

Reference numeral 10 denotes a control panel provided in a management office or the like, which is a microprocessor (MPU) for performing various processes.
11, a read-only memory (ROM) 12 connected to the MPU 11 for storing constants such as programs and gas leakage levels, and a random access memory (ROM) connected to the MPU 11 for storing various data and instructions ( RA
M) 13, an interface (I / F) 14 connected between the MPU 11 and the gas detector 5, and an I / F 15 connected between the MPU 11 and the shutoff valve 2a of the cylinder 2. . The various elements 5 and 2a in the cylinder cabinet 1 and the control panel 10 are connected by signal lines indicated by broken lines.

The conventional gas shutoff device is constructed as described above. When gas leaks from the cylinder 2 to the inside of the cylinder cabinet 1, the leaked gas is detected by the gas detector 5 and the gas is sent to the control panel 10. Send a leak signal. Then, a gas leak signal flows to the control panel 10, and the control panel 10 alerts the manager that the gas leakage has occurred. Therefore,
The administrator remotely operates the control panel 10 to stop the gas leakage by the shutoff valve 2a of the cylinder 2 such as the shutoff valve 2a disclosed in Japanese Utility Model Publication No. 5-5360.

[0006]

Gas leakage occurs due to loose joints in gas pipes, cracks in welding, and the like.
When the rate of gas leakage is slow, the gas spontaneously ignites, but when the rate of leakage is high, the gas continues to leak without ignition and diffuses in a raw gas state. If this raw gas state continues in the cylinder cabinet 1, the gas and air eventually mix and enter the explosion range. In this state, if the shutoff valve 2a of the cylinder 2 is closed from the control panel 10 as described above,
Since the leak rate at the time of closing is slow, spontaneous ignition will occur. In other words, this spontaneous combustion causes the pressure to rise rapidly, causing a large explosion. When handling flammable gases like this, the cylinder 2
It is highly possible that a large explosion will occur if the shutoff valve 2a is closed unnecessarily, and the gas concentration in the cylinder cabinet 1 is high even if the shutoff valve 2a is closed, so it is not known when the explosion will occur for some reason. There were challenges.

Therefore, the present invention has been made in order to solve the above-mentioned problems, and an object thereof is to obtain a gas shutoff device in which a gas explosion does not occur even if a gas leak is stopped when a gas leak is detected. .

[0008]

A gas shutoff device according to the present invention is provided with a shutoff valve which is filled with a gas having an ignitability and the like and which is opened and closed by a remote operation to stop the gas from leaking. A container, a container for containing the container, a gas detector provided in the container for detecting gas leaked from the container, filled with an inert gas, and opened / closed by remote control And a replacement container provided with a release valve for releasing the inert gas.

[0009]

In the present invention, when a gas leak is detected by the gas detector, the open valve of the replacement container is opened to replace the inside of the housing box with the inert gas so that the gas explosion does not occur.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic block diagram partially showing an embodiment of a gas shutoff device according to the present invention. In the cylinder cabinet 1A used in the present invention, FIG.
The cylinder 2 filled with the special material gas described in the related art example is placed. Further, an exhaust duct 3, a ventilation fan 4 and a gas detector 5 are also provided on the ceiling of the cylinder cabinet 1A.

Further, according to the present invention, a display portion 6 for indicating whether the current state is safe or dangerous is provided on the front surface of the cylinder cabinet 1A, and the oxygen concentration for measuring the oxygen concentration in the cylinder cabinet 1A is measured. A meter 7 is provided, for example, on the ceiling, and a pressure detector, such as a pressure sensor 8 for detecting the gas pressure on the secondary side of the cylinder 2, is provided, for example, on the secondary side of the shutoff valve 2a of the cylinder 2. In addition, in order to release an inert gas such as nitrogen into the cylinder cabinet 1A when a gas leak is detected, the cylinder 9 which is a replacement container filled with the inert gas is a cylinder cabinet 1A.
Is located outside of. An opening valve 9a that releases an inert gas by opening and closing the replacement cylinder 9 by remote control, and extends from the replacement cylinder 9 into the cylinder cabinet 1A through the opening valve 9a and discharges an inert gas. A pipe 9b having a discharge port 9c is provided. The opening valve 9a of the replacement cylinder 9 is the shutoff valve 2 of the cylinder 2.
It is the same as a.

The control panel 10A used in the present invention is also the MPU 11, the ROM 12, and the RAM explained in the conventional example of FIG.
13 and I / Fs 14 and 15, and a timer 17 connected to the MPU 11 via the I / F 16. In addition, the display unit 6 and the oxygen concentration meter 7 are the gas detector 5
Together with the signal line connected to the MPU 11 via the I / F 14, and the pressure detector 8 and the opening valve 9a of the replacement cylinder 9 together with the shutoff valve 2a of the cylinder 2 via the signal line.
It is connected to the MPU 11 via 15. The signal line may be provided for each device or may be commonly provided.

Next, the operation of the gas shutoff device of the present invention will be described. Similarly to the conventional example, when gas leaks from the cylinder 2 into the cylinder cabinet 1A, the gas detector 5 detects the leaked gas and sends a gas leak signal to the control panel 10A. As a result, "danger" is displayed by a signal from the control panel 10A to the display unit 6 of the cylinder cabinet 1A. Next, before closing the shutoff valve 2a of the cylinder 2, the opening valve 9 of the replacement cylinder 9 is signaled by a signal from the control panel 10A.
By automatically opening a, the inert gas filled in the replacement cylinder 9 is discharged into the cylinder cabinet 1A from the discharge port 9c through the pipe 9b. As a result, the mixed atmosphere of the flammable gas and the air in the cylinder cabinet 1A is replaced with the inert gas, and as a result, the concentration of oxygen is lowered (this is measured by the oxygen concentration meter 7) and the gas and the air are mixed. The mixed atmosphere of (oxygen) is forced out of the explosion range. After that, or after a lapse of a certain time from the start of the discharge of the inert gas (that is, after a predetermined set time by the timer 17 in the control panel 10A), the shutoff valve 2a of the cylinder 2 is automatically closed as in the conventional example. . The subsequent gas pressure on the secondary side of the cylinder 2 is detected by the pressure detector 8. When it is detected that the detection level of the pressure detector 8 becomes equal to or lower than a predetermined value, the control panel 10A notifies the safety and sends a safety signal to the display unit 6 to display a safety display.

By doing so, the control panel 10A can confirm that the inside of the cylinder cabinet 1A has become safe. Further, it is safe because the display portion 6 of the cylinder cabinet 1A shows the state of the inside of the cylinder cabinet 1A, and a person in the vicinity does not approach innocently.

Even if the gas leak rate decreases to the rate of self-ignition when the shutoff valve 2a is closed, there is insufficient oxygen, so self-ignition and therefore explosion does not occur. As described above, in the present invention, the gas leaked from the cylinder 2 can be safely discharged from the exhaust duct 3 to the outside of the cylinder cabinet 1A, and the gas explosion does not occur even when the shutoff valve 2a of the cylinder 2 is closed.

Next, the operation of the control panel 10A will be described with reference to the flowchart of FIG. First, in step S1, based on the program stored in the ROM 12,
The MPU 11 reads the detection level of the gas detector 5 via the I / F 14, and the detection level is read in step S2.
It is determined whether or not there is a gas leak by comparing with a predetermined value in the OM 12. If it is determined that the gas is not leaking, the program returns to step S1, but if the gas is leaking, the program proceeds to step S3 to display “danger” on the display unit 6 and to open the replacement cylinder 9 at step S4. Valve 9
When a is opened, the inert gas is discharged into the cylinder cabinet 1A as described above. Next, the program proceeds to step S5, at the same time when the opening valve 9a is opened, the timer 17 in the control panel 10A is started, and at step S6, the timer 1
7 determines whether a predetermined set time has elapsed, and if it has elapsed, the shutoff valve 2a of the cylinder 2 is closed in step S7 to stop gas leakage.

However, if it is determined in step S6 that the predetermined set time has not elapsed, the process proceeds to step S8 to read the detection level of the oxygen concentration meter 7, and in step S9 the detection level is set to a predetermined value K () in the ROM 12. If the oxygen concentration is less than K, the process returns to step S6. If the oxygen concentration is less than K, the process proceeds to step S7. The timer 17 and the oxygen concentration meter 7 are the shutoff valve closing permission means, and the shutoff valve 2a is closed, that is, not closed unless either the condition of step S6 or S9 is satisfied.
By doing so, the shut-off valve 2a is closed after the cylinder cabinet 1A is sufficiently filled with the inert gas.

After closing the shut-off valve 2a of the cylinder 2 in step S7, the flow advances to step S10 to read the gas pressure level detected by the pressure detector 8, and in step S11 this detection level is set to a predetermined value in the ROM 12. Compared with A, if gas pressure <A is not satisfied, the process returns to step S10, but if gas pressure <A, the process proceeds to step S12. This predetermined value A is a value slightly larger than 0, and the shutoff valve 2a
Is completely closed and the pressure on the secondary side of the cylinder 2 becomes 0, the process proceeds to step S12. And step S12
After "Danger" is erased on the display unit 6 and "Safety" is displayed, the program returns to step S1. At this time, the opening valve 9a of the replacement cylinder 9 is closed.

FIG. 1 shows an example in which the replacement cylinder 9 is placed outside the cylinder cabinet 1A. However, if the cylinder cabinet 1A has sufficient space, the replacement cylinder 9 is placed inside the cylinder cabinet 1A. May be.
Further, instead of the safety display, the state may be notified by voice.

[0020]

As described above in detail, the gas shut-off device according to the present invention is a shut-off device that is filled with gas having a property of ignitability and is opened / closed by remote control to stop the leakage of the gas. A container provided with a valve, a storage box for storing this container, a gas detector provided in the storage box for detecting gas leaked from the container, filled with an inert gas, and operated remotely. A replacement container provided with an opening valve that releases the inert gas when opened and closed, and when the gas leak is detected by the gas detector, the opening valve of the replacement container is opened to open the replacement container. Since the inside of the containing box is replaced with the inert gas, the inside of the containing box is filled with the inert gas, and therefore, when the shutoff valve of the container is closed, even if the gas leak rate becomes slower, ignition does not occur. ,
As a result, the gas explosion does not occur. Further, since the replacement container is placed outside the storage box, there is an effect that the gas is not ignited even if static electricity is generated when the opening valve of the replacement container is opened. Further, since the shutoff valve of the container is closed after a certain time after the inert gas is released, that is, after a predetermined set time of the timer, the shutoff valve cannot be closed even if the shutoff valve is manually closed. There is also an effect that erroneous operation can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing a partial block diagram of an embodiment of a gas shutoff device according to the present invention.

FIG. 2 is a flowchart for explaining the operation of the present invention.

FIG. 3 is a schematic configuration diagram showing a partial block diagram of a conventional gas shutoff device.

[Explanation of symbols]

 1A Cylinder cabinet 2 Cylinder 2a Shut-off valve 5 Gas detector 6 Display 7 Oxygen concentration meter 8 Pressure detector 9 Replacement cylinder 9a Open valve 10A Control panel 11 MPU 17 Timer

Claims (3)

[Claims] 1. A gas having properties such as ignitability is filled,
Further, a container provided with a shutoff valve that stops the gas leakage by being opened and closed by remote operation, a storage box that stores this container, and a gas that is provided inside the storage box and that leaks from the container is detected. A gas shutoff device comprising: a gas detector; and a replacement container further provided with an opening valve that is filled with an inert gas and that is opened and closed by remote control to release the inert gas, When the gas leak is detected by the gas detector,
A gas shutoff device, characterized in that an opening valve of the replacement container is opened to replace the inside of the accommodation box with the inert gas. 2. The gas shutoff device according to claim 1, wherein the replacement container is placed outside the storage box. 3. A timer is provided which is activated at the same time when the opening valve of the replacement container is opened, and the shutoff valve of the container is closed after a predetermined set time of the timer.
Or the gas shutoff device of 2.