JPH0325212A - Gas explosion preventing device - Google Patents

Abstract

PURPOSE:To enable execution of a release work only by disconnecting a minimum power source by a method wherein a source disconnection distance in which a distance from a position where leakage of gas occurs is gradually increased according to gas concentration and a time is provided by fuzzy inference, and based on the distance, the power source is disconnected. CONSTITUTION:A gas concentration detector 2 to detect gas concentration is arranged in the vicinity of a gas device 1, and concentration signal is inputted to a fuzzy controller 3 directly and through a differential circuit 4. With the progress of input of the signal, the fuzzy controller 3 outputs a disconnection distance signal by means of which power sources are disconnected, in order, in response to a distance from the gas device to the gas device according to a diffusion state of leak gas when leakage of gas from the gas device 1, and the output is inputted to a discriminating circuit 6. Further, the discriminating circuit 6 outputs a signal, by means of which a power source is disconnected, to a necessary source control part through comparison of distances from the gas device 1 to source control parts 7a, 8a, 9a... with each other based on a disconnection distance signal. This constitution facilitates a release work.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a prevention device for preventing an explosion in the event of a gas leak.

[Conventional technology]

Conventionally, devices are known in which a monitor or the like is installed near a gas appliance in order to detect gas leaks, etc., and when the gas concentration reaches a certain value, a buzzer or lamp is turned on to notify the gas leak status. .

[Problem to be solved by the invention]

However, when the gas concentration reaches a predetermined value, there is a risk of a gas explosion due to the opening and closing of contact switches caused by lighting lights or using electrical appliances. Furthermore, if all the t-sources are shut off by the output of a monitor or the like when a gas leak occurs, there is a drawback that it becomes difficult to perform work to eliminate the gas leak, which can even become dangerous. The technical object of the present invention is to facilitate restoration work when such a gas leak occurs and also to prevent a gas explosion.

[Means to solve the problem]

The present invention includes a gas concentration detector, a clock means that starts operating when the concentration obtained from the gas concentration detector exceeds a predetermined value, a plurality of power supply control units that individually control a plurality of 1 tB, and a gas concentration detector. A plurality of fuzzy inference units that perform fuzzy inference to sequentially cut off power supplies near the gas source as the output from the detector increases and the time for gas leakage from the clock means increases, and each fuzzy inference unit is parallel. The apparatus is characterized by having a determination section that obtains a non-fuzzy determined value of the power cutoff distance based on the output, and a discrimination circuit that connects or disconnects the plurality of power supply control sections based on the power supply cutoff distance obtained from the determination section. be.

[Effect]

According to the present invention having such characteristics, the gas concentration is detected by the gas concentration detector, the time after the concentration reaches a predetermined level is detected by the clock means, and the time is detected in correspondence with the gas concentration and the time. Fuzzy reasoning is used to obtain power-suppressing cutoff distances that gradually increase in distance from the location where the gas leak occurs, and the power is cut off based on that distance. [Effects of the Invention] Therefore, according to the present invention, it is possible to use electrical appliances at locations where gas has not reached, and as the gas diffuses, it is possible to cut off power supplies at locations distant from the gas appliances. Therefore, restoration work can be carried out by simply cutting off the minimum amount of power, and furthermore, it is possible to prevent gas explosions.

[Explanation of Examples]

FIG. 2 is a block diagram showing the overall structure of a gas explosion prevention installation according to an embodiment of the present invention. In this figure, a gas concentration detector 2 for detecting gas concentration is arranged near a gas appliance l. The gas concentration detector 2 detects the concentration when gas leaks from the gas appliance 1, and its concentration signal is given to the fuzzy controller 3 directly and via the differentiation circuit 4. The concentration signal is also given to the clock 5. The clock 5 starts operating after the time when a gas concentration exceeding a predetermined level is detected and counts the gas leakage time, and the time signal is given to the fuzzy controller 3. In response to these inputs, the fuzzy controller 3 outputs a cutoff distance signal to sequentially cut off the power supply according to the distance from gas appliance to gas appliance, depending on the diffusion state when gas leaks from the gas appliance 1. The output is given to the discrimination circuit 6. The discrimination circuit 6 connects the gas appliance 1 to each power supply control unit 7a, based on the cutoff distance M signal.
By comparing the distances to 8a, 9a, etc., a signal is given to the necessary power supply control unit to cut off the power. The power supply control units 7a, 3a, . . . are connected to electric lights and other various electric devices 7b, 8b, .
is connected. Next, the structure of the main part including the fuzzy controller 3 will be explained as follows.
This will be explained with reference to the figure. In this embodiment, fuzzy control is performed based on the output of the gas concentration detector 2, its differential output, and the time signal from the clock 5.

The fuzzy controller 3 consists of a plurality of fuzzy inference sections and a determination section. Each input shown in Figure 2 has multiple inputs,
In this embodiment, the information is transmitted to eight fuzzy subsections 11-1 to IL8. As shown in the figure, each fuzzy inference unit includes a membership function generation circuit (MFC) that generates a membership function corresponding to an input gas concentration, its differential output, and a time signal, and a membership function that generates a membership function of a distance signal to be output. A membership function generator (MFG) is provided to generate a membership function generator (MFG). Now, in this example, the gas concentration is divided into four states as a membership function as shown in Fig. 3 (a), and its differential value is divided into seven states as shown in Fig. 3 (bl, (C)). , the time after the gas leak is divided into four states.The distance signal for power cutoff is also divided into seven states as shown in Figure 3(d).Here, NL is a large negative value, and NM is a large negative value. is a medium negative value, NS is a small negative value, ZR
is almost zero, PS is a small positive value, PM is a medium positive value,
PL represents a large positive value. Furthermore, Figure 3(d)
For example, the distance from the gas appliance 1 is 4 m as zero, and the positive and negative values are expressed.

Next, the fuzzy inference units 1l-1 to 11-8 will be explained. Each fuzzy inference unit has two or three MFC21
-1~21-8.22-1~2 2-8. 2 3-
2 to 23-8. The fuzzy inference unit 11-1 is an inference unit that performs the inference of rule 1 as described later, and
In FC21-1, output S1 from gas concentration detector 2 is PS
A generation circuit (MFC) that generates the membership function of
, MFC2 2-1 output S2 from differential rotation 4 is ZR
The MFC generates a membership function, and each output is given to the MiN circuit 24-1. Also MFG25
-1 is a membership function generator (MFG) that generates a parallel membership function NM of the power cutoff distance shown in FIG. 3(d), and its parallel output is a MINrM path 26-
1 is given. MIN circuit 26-1 is MIN circuit 24
-1 output, a smaller parallel fuzzy signal is generated, and the output thereof is given to the MAX array circuit 27.

Next, the inference rules determined based on these inputs are shown below.

(Rule 1) If the gas concentration (S1) is PS and its differential value (S2) is Z
If R, let NM be the power cutoff distance (e). This rule 1 is simplified and expressed as follows.

If S1= P S and 52- Z R t
hen NMSuch a rule stipulates that when the gas concentration is high and the differential value increases in the positive direction, the distance for power cutoff increases as the time after occurrence increases, and as the differential value changes in the negative direction, it decreases. It will be done.

Such rules are shown in the table below.

In this way, eight inference rules are defined. The fuzzy inference units 11-1 to 11-8 are inference units that execute respective fuzzy inferences, and the parallel fuzzy outputs that are the inference results of the respective rules are outputted from the fuzzy inference units 11-1 to 11-8.
The signal is applied to the AX array circuit 27. MAX array circuit 2
7 calculates the maximum value for each corresponding line of each parallel line, and the parallel output is sent to the defuzzifier circuit 2.
given to 8. The defuzzifier circuit 28 obtains a non-fuzzy output by calculating the center of gravity of its output.
The output is given to the discrimination circuit 6. The discrimination circuit 6 discriminates this distance signal according to the distance between the gas appliance 1 and each power supply control section, and sends a power cutoff control signal to each power supply control section.
It is given to a, 8a...

Next, the operation of this embodiment will be explained. First, the output 81 of the gas concentration detector 2 is a predetermined value s1. And PS-0.3
, PM=0.7, and the output S2 from the differentiator circuit is
is S2o, PS-0.4, PM-0.6,
The time 33 after the gas concentration reaches the predetermined value is the predetermined value S3
(l and Z R =0.2. P S-0.8. In this case, rules 2.4 and 5 of the rule table described above are applied, and the power cutoff distance e is as follows.

ZR father-in-law 0.3. PM=0.3, PS=O.

7. Therefore, fuzzy parallel outputs are obtained from three of the eight fuzzy inference sections, and these outputs are subjected to MAX calculation by the MAX array circuit 27 of the determining section 12. As a result, as shown in Figure 3(d), the interception distance e is calculated by calculating the center of gravity.
This signal is discriminated by the discrimination circuit 6, and the power supply at that position is cut off. For example, if the distances between the gas appliance 1 and the power control units 8a and 9a in FIG. 2 are 6 m and 8 m, respectively,
is 7.5 m, the power source closer than the distance e,
That is, the power supply control units 7a and 3a are cut off. Power supply control units 9a outside of this are not shut off. Therefore, the power supply control section 7
Although the lights and electric appliances 7b and 8b connected to the power supply controllers a and 8a do not operate, the power to the appliances connected to the power supply control section 9a is not cut off. Therefore, you can continue to use lights and other electrical equipment. In this embodiment, the power supply is cut off in accordance with the distance to the gas appliance based on the concentration of the gas concentration detector, its differential value, and the time since the gas leak occurred, but a differential circuit is used. It is also possible to achieve this without.

Further, although this embodiment describes a gas explosion prevention device that performs fuzzy reasoning according to the MIN-MAX calculation rule, the present invention can also be realized by fuzzy reasoning according to other calculation rules. Further, fuzzy processing is carried out using a dedicated device for fuzzy inference (for example, Nikkei Electronics, July 28, 1987, pp. 148-152).
Page, Nikkei McGraw-Hill), but also a binary type computer, processor, etc. programmed to perform fuzzy inference. Furthermore, the membership function is not limited to the triangular shape shown in Figure 3, but may be of any shape. Furthermore, membership functions and inference rules are peripheral. It can be changed or modified as appropriate depending on the environment, the properties of the equipment, etc.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the main parts of a gas explosion prevention device according to an embodiment of the present invention, Fig. 2 is a block diagram showing its overall structure, and Fig. 3 (a) shows the gas concentration. FIG. 3(b) is a diagram showing the differential value, FIG. 3(C) is a diagram showing the membership function of time, and FIG. 3(d) is a diagram showing the membership function of the power cutoff distance. 1... Gas appliance 2... Gas concentration detector 3... Fuzzy controller
4-...Ittetsu circuit 5...Clock 6...
...Discrimination circuit 7a, 3a, 9a...1...
Power supply control section 7b. 8b. 9b...1...Electrical appliances 11-1~11~8...Fuzzy reasoning section 1
2・-・・・Decision part 21.22.23・・・・
...-MFC24.26--MiN circuit 25
...1.MFC27-...MAX array circuit 28.--Defuzzifier circuit

Claims (1)

[Claims] (1) a gas concentration detector; a clock unit that starts operating when the concentration obtained from the gas concentration detector exceeds a predetermined value; and a plurality of power supply control units that individually control the plurality of power supplies; a plurality of fuzzy inference units that perform fuzzy inference so as to sequentially cut off power supplies near the gas generation source as the output from the gas concentration detector increases and the time for gas leakage from the clock means increases; The determining unit includes a determination unit that obtains a non-fuzzy determined value of the power cutoff distance based on the parallel output of the inference unit, and a discrimination circuit that connects or disconnects the plurality of power supply control units based on the power cutoff distance obtained from the determination unit. A gas explosion prevention device featuring: