JP2581573B2 - Gas leak accident prevention device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a gas leakage accident prevention device.

(Prior art) As is well known, when gas leaks from various gas appliances and gas pipelines, there is a danger of causing not only a problem in human health but also a gas explosion in some cases. Not to mention the structure of various kinds of equipment and instruments, various regulations are imposed on the production, and furthermore, on the place of installation and the way of use, etc. As a result, gas leaks may occur accidentally due to abrasion or mishandling that occur naturally, and as a safety device, an alarm is activated based on the detection signals of various improved and improved gas leak detection devices. Various types of gas leakage accident prevention devices have been proposed which operate various members for supplying and stopping gas supply.

By the way, looking at the gas leak detection method incorporated in the various gas leak accident prevention devices described above, this is a method for detecting an abnormality in the gas flow rate in the gas pipeline when using the gas. And a method of detecting a decrease in the pressure of the gas in the gas pipeline when not in use.

(Problems to be Solved by the Invention) In view of the gas leakage accident prevention device that incorporates the latter method, which has been generally adopted recently, among the above-described methods, this is the case where LP gas is used. As shown in FIG. 2 for the example, the consumer stops using the gas appliances GS ₁ , GS ₂ ,... And the gas supply main pipe 1 near the LP gas cylinder B.
When the gas supply is shut off by a shutoff valve 4 (safety valve) such as an electromagnetic valve which is opened and closed by an operation button of a valve operation unit T, the main pipe 1, the branch pipe 2, and the branch pipe
If gas trapped in the gas pipeline consisting of 3 ₁ , 3 ₂ , 3 ₃ , etc. leaks for any reason,
When the gas trapped leaks in the gas conduit, using a phenomenon that the gas pressure decreases, the mode of decrease of the gas pressure detected by the pressure sensor P _1, pressure or gas pressure of the detection gas Is compared with a controller C 'having a built-in comparison circuit for comparing this gas pressure with a preset allowable gas pressure (hereinafter, this may be simply referred to as a set value or a predetermined value). Then, on the one hand, the alarm A is actuated, and on the other hand, the shut-off valve 4 is closed via the signal transmitter t from the controller C 'which keeps the shut-off valve 4 from opening even if the valve operating part T is operated. However, in this type, as with other detection methods of this type, the ambient temperature is
No consideration was given. By the way, the pressure of the gas, including the gas confined in the pipe, does not change in volume, so if the temperature (absolute temperature) is reduced by half according to Boyle-Ciel's law, the pressure will also be reduced by half. Therefore, even if there is no gas leakage, if the temperature decreases, the pressure decreases, and the controller C '
Activates the alarm A, that is, causes the alarm A to malfunction or closes the shut-off valve 4.

Incidentally, in regard to LP gas, typically the temperature variation of the standard supply pressure in LP gas 280 mm H ₂ O, the set value of the gas pressure sensor has become a 140~190mm H ₂ O, this time 1
Since the pressure change per ° C is about 40 mm H ₂ O, about 3.5 ° C
If the temperature changes (280-140) / 40, the pressure sensor will be activated and an alarm will be issued, that is, a false alarm.

Also, as described above, when a false alarm is issued, in other words, even when there is virtually no gas leakage, the valve operating unit T
Unless the function of the signal transmitter t is stopped by the operation of
There was also inconvenience and inconvenience that the shut-off valve 4 was not immediately opened by the operation of the valve operation part T.

(Means for Solving the Problems) In view of the above situation, the present invention relates to a gas pipe for forming a gas pipeline, which is provided downstream of a shutoff valve for supplying and stopping gas supply. A gas pressure detector that constantly detects the gas pressure in the gas pipe, and a shutoff valve that is connected to the gas pipe downstream of the shutoff valve and that opens and closes in accordance with the opening and closing operation of the shutoff valve. And comparing each other signal from the gas detection unit that detects the gas pressure in the gas containment tube formed so as not to cause gas leakage, and the difference is a predetermined value or more that is determined according to the ambient temperature A signal from a controller having a logic circuit that transmits a signal only when the alarm signal is generated, an alarm device that issues an alarm based on the signal, and a shut-off valve that is operated by operating a valve operating unit that opens and closes the shut-off valve. Signal to prevent release By transmitting the signal to the transmitter, it is possible to eliminate the cause of the false alarm that disturbs the human body, and to eliminate the cause of the malfunction of the shut-off valve provided for supplying and stopping the gas supply. This is a gas leakage accident prevention device characterized in various places.

(Operation) The gas leakage accident prevention device according to the present invention has the above-described configuration, and when it is used, it is attached to a gas pipe for forming a gas pipeline to supply and stop the supply of gas to gas appliances. When the shut-off valve to be provided is opened and the shut-off valve attached to the gas containment pipe is opened, gas flows into the gas pipe on the gas pipe forming side and into the gas containment pipe, and the gas can be used. Since the gas pressure in the pipe and the gas containment pipe are substantially equal, the controller that receives the gas pressure detection signal from the gas pressure detection section on the gas pipe side and the gas pressure detection section on the gas containment pipe side issues an alarm. It does not transmit the signal for operating the alarm and the signal transmitter, the alarm and the signal transmitter are not operated, and the shut-off valve can be freely operated by the valve operating section.

Further, when the use of gas is stopped for a long time, such as at night, if the shut-off valve attached to the gas pipe for forming the gas pipeline is closed and the shut-off valve attached to the gas containment pipe is also closed, the gas is released. It will be enclosed in the gas pipe and the gas containment pipe.

At this time, if there is no gas leak from the gas pipe, or if there is no gas leak exceeding a set value which is an allowable range, the gas pressure on the gas pipe side is detected following the change in ambient temperature and compared by the controller. The difference between the detection signal value from the detection unit and the detection signal value from the gas pressure detection unit on the gas containment tube side falls within a predetermined value following the temperature change, and the alarm and the signal transmitter are not activated. The shut-off valve can be freely operated by the valve operating section.

However, if there is a gas leak that exceeds the allowable range from the gas pipe for gas pipe formation, it follows the ambient temperature change, is detected under the same conditions, and the gas pipe is compared by the controller. The difference between the detection signal value from the gas pressure detection unit on the side and the detection signal value from the gas pressure detection unit on the gas containment tube side becomes equal to or greater than a predetermined value that follows the temperature change. A signal for operating the signal transmitter is transmitted, the alarm issues an alarm, and informs whether there is a gas leak, and the signal transmitter transmits a signal to maintain the closed state of the shut-off valve and maintains the closed state. It will be.

(Embodiment) Hereinafter, an embodiment of a gas leakage accident prevention device according to the present invention is shown, and the same or equivalent components as those of the conventional gas leakage accident prevention device shown in FIG. 2 are denoted by the same reference numerals. Thus, an embodiment of the present invention will be described in detail with reference to FIG. 1 in which the description is simplified and simplified.

In FIG, B is LP gas cylinder, 1 LP gas supply main pipe, 2 branch pipe, 3 _1, 3 _2, 3 _3, ... in the branch pipe, LP gas line by each of these tubes (hereinafter, A gas valve is formed near the LP gas cylinder B of the main pipe 1, and a shut-off valve (safety valve) such as a solenoid valve for supplying and stopping the supply of LP gas (hereinafter, simply referred to as gas). The branch pipes 3 ₁ , 3 ₂ , 3 ₃ ,... Are connected to gas appliances (gas ranges for combustion, etc.) GS ₁ , GS ₂ , GS ₃ ,.

P ₁ is a pressure sensor as a gas pressure detection unit installed in the main pipe 1 so as to be downstream of the shutoff valve 4.
P ₂ is a pressure sensor similar to the pressure sensor P _1, and the pressure sensor P ₂ is a gas connected to the main pipe 1 at the same position as the pressure sensor P ₁ via a shutoff valve 5 similar to the shutoff valve 4. It is installed in a strong gas containment tube M that does not cause leakage.

Further, C receives and compares the detection signals from the pressure sensors P ₁ and P ₂ which detect the gas pressure in the main pipe 1 and the gas pressure in the gas containment pipe M which change according to the ambient temperature. A signal that activates the alarm A to issue an alarm only when the gas leakage exceeds a predetermined value as an allowable gas leakage range determined in accordance with the temperature of the gas, and a cut-off valve (not shown) that opens and closes the shut-off valve 4 A signal for maintaining the closed state of the shut-off valve 4 is transmitted between the valve operating section T having an operation button and the shut-off valve 4 in preference to the open / close signal of the shut-off valve 4 from the valve operating section T. And a signal for transmitting a signal to activate the signal transmitter t. The valve operating section T also has an operation button for releasing the function of the signal transmitter t.

Therefore, gas appliances GS ₁ , GS ₂ , GS ₃ , ...
When gas is supplied to…, by operating the operation button of the valve operation unit T and simultaneously opening the shutoff valve 4 and the shutoff valve 5 via the signal transmitter t, the gas is supplied to each gas appliance GS ₁ , GS ₂ , GS ₃ ,..., And can be used by opening and closing the valves of each gas appliance GS ₁ , GS ₂ , GS ₃ ,..., While the gas is also filled in the gas containment pipe M. It will be.

Then, as at night or the like, each gas appliance _{GS 1, GS 2, GS 3} , ......
When the use is stopped, the valve operating section T is operated to close the shut-off valve 5 together with the shut-off valve 4 and the main pipe 1
, The branch pipe 2 and the branch pipes 3 ₁ , 3 ₂ , 3 ₃ ,..., Etc., and the gas in the gas containment pipe M are individually contained in the gas. sensor P _1, P
₂ will be detected.

By the way, even if the detected value of the gas pressure detected by the pressure sensors P ₁ and P ₂ cannot be leaked from either the gas pipe or the gas containment pipe M, the pressure sensors
Since P ₁ and P ₂ are under the same condition, the controller C, which has received the signals corresponding to the detection values from the two pressure sensors P ₁ and P ₂ , controls the alarm A and the signal transmitter t. It does not send a signal to activate, but if gas leaks from the gas line, it responds to the ambient temperature and follows the pressure sensor
Each detection value P ₁ and the pressure sensor P ₂ is compared in the controller C, if the difference is within tolerance value gas leakage predetermined in response to the ambient temperature, alarm device A and the signal The transmitter t is not operated, but when the value is equal to or more than the above value, a signal for activating the alarm A and the signal transmitter t is sent, the alarm A generates an alarm, and the signal transmitter t operates the valve. In order to prevent the shut-off valves 4 and 5 from being opened even when the part T is operated, a signal for keeping the shut-off valve 4 in the closed state is transmitted.

(Effects of the Invention) As is clear from the above description, according to the present invention, the conventional gas leakage that is performed by simply detecting only the gas pressure of the gas confined in the gas pipe for forming the gas pipeline. Unlike an accident prevention device, an alarm device based on a detection value that can accurately detect gas leakage that is not affected by changes in the surrounding temperature, etc., and a shut-off valve installed in the gas pipeline that controls the supply and stop of gas supply It has become possible to provide a gas leakage accident prevention device that does not cause malfunctions.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a configuration of an embodiment of a gas leakage accident prevention device according to the present invention, and FIG. 2 is a schematic diagram for explaining a configuration of an example of a conventional gas leakage accident prevention device. B; LP gas cylinder 1; Main pipe for supplying LP gas, 2; Branch pipe 3 ₁ , 3 ₂ , 3 ₃ , ...; Branch pipe 4, 5; Shut-off valve GS ₁ , GS ₂ ,…; Gas appliance P ₁ , P ₂ ; Pressure sensor C, C '; Controller, M; Gas containment tube A; Alarm, t; Signal transmitter T; Valve operating part

Claims (1)

(57) [Claims] A gas detector attached to a gas pipe of a gas pipe type for constantly detecting a gas pressure in a gas pipe downstream of a shut-off valve provided for supplying and stopping gas supply; A gas in a gas containment pipe, which is connected to a gas pipe downstream of the shutoff valve, is provided with a shutoff valve that opens and closes in accordance with the opening and closing operation of the shutoff valve, and is formed so as not to cause gas leakage. Control with a logic circuit that compares each signal from the gas pressure detector that detects the pressure and sends a signal only when the difference exceeds the allowable gas pressure determined according to the ambient temperature The signal from the vessel
An apparatus for preventing a gas leak accident, wherein the alarm is issued to an alarm device for issuing an alarm based on the signal and a signal transmitter for maintaining the closed state of the shut-off valve.