JP2000059985A - Simplified explosion-proof system in hazardous place - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the explosion-proofness in a so-called 2nd grade hazardous place simply and securely with a low cost construction. SOLUTION: An electric apparatus 21 and a gas detector 22 which detects a hazardous atmosphere produced in a 2nd grade hazardous place are installed in a 2nd grade hazardous place where there is the possibility of producing a hazardous atmosphere in an abnormal state. A backup power supply 23 composed of a secondary battery such as a lead storage battery, etc., for the backup of power supply interruption is installed in a non-hazardous place. Further, a protective box 24 which is made to operate by the output of the gas detector 22 and cuts off the power supply route for the electric apparatus 21 is installed in the non-hazardous place. In a normal state, a commercial power supply current is rectified by a power supply circuit 25 to obtain a DC current which is supplied to the electric apparatus 21 and the gas detector 22 and, at the same time, supplied to the backup power supply 23 as a charging current. In a power supply interruption state, the electric apparatus 21 and a gas detector 22 are driven.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simple explosion-proof system in a hazardous place for preventing explosion in two kinds of dangerous places where a dangerous atmosphere may be generated in an abnormal state.

[0002]

2. Description of the Related Art According to the Technical Guidelines of the Industrial Safety Research Institute of the Ministry of Labor, from the viewpoint of implementing balanced explosion-proof measures, according to the time and frequency of the presence of a dangerous atmosphere,
Dangerous locations are classified into three types, a type 0 location, a type 1 location, and a type 2 location.

[0003] When electric equipment such as control equipment is used in two kinds of dangerous places where a dangerous atmosphere may be generated in an abnormal state, for example, when a flammable gas leaks in an abnormal state, these electric equipments are used. In general, it is necessary to use an electric device having a pressure-resistant explosion-proof structure as shown in FIG. 3 or an internal pressure explosion-proof structure as shown in FIG.

[0004] Here, in FIG.
Is a pressure-resistant container accommodating the electric device 1, 3 is a power supply external wire lead-in portion provided in the pressure-resistant container 2 for supplying power to the internal electric device 1, and 4 is a pressure-resistant container for connecting the electric device 1 to the external device. This is an external electric wire lead-in part provided in the container 2. In FIG. 4, reference numeral 6 denotes a housing-shaped internal pressure panel that accommodates the electric device 1, reference numeral 7 denotes a pressure adjusting valve for supplying air at a predetermined pressure from an air source (not shown) into the internal pressure panel 6, and reference numeral 8 denotes an internal pressure. An internal pressure monitoring panel 9 monitors the pressure in the panel 6 and supplies power to the electric device 1. Reference numeral 9 denotes an external wire lead-in portion from the electric device 1 to an external device.

[0005]

However, in the case of the explosion-proof structure shown in FIG. 3, since the whole is very large, a large installation space is required and the weight is very heavy. However, it is difficult and expensive.

On the other hand, in the case of the internal pressure explosion-proof structure shown in FIG. 4, since the internal pressure monitoring panel 8 and the air source are separately required, the whole structure becomes large and expensive, and especially when the air is shut off for some reason. There is a problem that the function of the stored electric equipment cannot be performed.

Therefore, in order to solve the problems in the pressure-resistant explosion-proof structure and the internal pressure explosion-proof structure, it has been proposed to provide a simple explosion-proof system by providing detection means for detecting a dangerous atmosphere in two types of dangerous places. However, when the detection means uses a commercial power supply as a power source, the power supply to the detection means itself cannot be performed at the time of a power failure, and the detection means does not operate.

For this reason, it is conceivable to provide a backup secondary battery to perform a power failure backup of the detecting means. However, since the secondary battery itself generates dangerous gas such as hydrogen, it is not possible to install the secondary battery as it is in two types of hazardous places, and the secondary battery itself must be provided with explosion-proof measures. However, there is an inconvenience that explosion-proof measures for secondary batteries are difficult and cannot be easily performed.

A first object of the present invention is to provide an inexpensive configuration for explosion protection in so-called two hazardous locations.

[0010] It is a second object of the present invention to make it easier and more reliable to prevent explosion in two types of dangerous places.

[0011]

In order to solve the above-mentioned first problem, the present invention provides a gas detector installed in two kinds of dangerous places where a dangerous atmosphere may be generated in an abnormal state; And a protection means which operates in response to the detection output of the gas detector and cuts off a power supply path of a commercial power supply to the electric equipment installed in the two types of dangerous places.

According to such a configuration, the gas detector can detect the hazardous atmosphere in the two types of hazardous places, and the output thereof activates the protection means so that the electrical equipment installed in the two types of hazardous areas can be detected. Is cut off. for that reason,
It is not necessary to make the electric equipment itself a pressure-resistant explosion-proof structure or an internal pressure explosion-proof structure as in the related art, and explosion protection in two types of hazardous locations can be performed with an inexpensive configuration.

Further, in order to solve the above-mentioned second problem, in the present invention, the gas detector uses a commercial power supply as a power supply in a normal state, and uses a backup power supply provided for a power failure backup as a power supply in a power failure. It is characterized by:

With this configuration, the gas detector operates by being supplied with power from the backup power supply even at the time of a power failure.
Even a dangerous atmosphere generated during a power outage can be detected, and the protection means can be operated by the output of the gas detector at that time.

Further, in order to solve the above-mentioned first and second problems, according to the present invention, the backup power supply comprises
The secondary battery is characterized by being supplied with a charging current by a charging means using a commercial power supply as a power source during non-power failure.

In this case, since the backup power supply is always charged unless the commercial power supply fails, it is necessary to periodically check the remaining capacity, for example, when the backup power supply is constituted by a primary battery. This is unnecessary, and maintenance of the backup power supply is simplified.

Further, in order to solve the above first and second problems, the present invention provides the above-mentioned power supply, wherein the backup power supply is provided in a recess formed in a partition wall between the two dangerous places and the non-hazardous place. It is characterized by being arranged.

By doing so, no special space is required for installing the backup power supply, the backup power supply can be installed in a non-hazardous area without protruding outside, and the appearance is not impaired. Also, installation and wiring work can be easily performed.

Further, in order to solve the above-mentioned first and second problems, the present invention is characterized in that the protection means has a pressure-resistant explosion-proof structure and is installed in the two kinds of dangerous places. I have.

In this case, due to the installation space, when it is absolutely necessary to install the protection means in two kinds of dangerous places, it is possible to install the protection means in the two kinds of dangerous places by using a pressure-resistant explosion-proof structure. In particular, it is effective as an explosion-proof system inside buildings with limited space.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described with reference to FIG.

In FIG. 1, reference numeral 20 denotes a partition wall between a non-hazardous location and a two-risk location which may generate a dangerous atmosphere in an abnormal state, and 21 denotes a two-dimensional danger location and a controlled device (not shown) Electrical equipment such as a control device for controlling the
Reference numeral 2 denotes a gas detector which is installed in a two-risk area and detects the generation of a dangerous atmosphere in the two-hazard area; 23, a backup power supply which is installed in a non-hazardous area; Reference numeral 24 designates a non-hazardous location, which is operated by a pair of normally closed contacts 24a1 and 24a2 and the output of the gas detector 22, and both normally closed contacts 24a1 and 24a.
2 is a protection box as a protection means comprising a protection circuit section 24b for opening 2;
The power supply circuit is connected to a commercial power supply and a backup power supply 23 via a1 and 24a2, respectively, and has an output terminal connected to the electric device 21 and the gas detector 22.

Then, as shown in FIG.
In the middle of the current path connecting the power supply and the commercial power supply and the backup power supply 23, both normally closed contacts 24a1,
24a2, and the normally closed contacts 24a1, 24a2
, The power supply path to the electric device 21 is cut off. Since these normally closed contacts 24a1 and 24a2 are constituted by, for example, latch relays, once opened, they can be restored only by manual operation. It should be noted that the electric device 21 referred to here means that when a dangerous atmosphere is generated,
It is an electrical device that does not hinder its function even if its function is stopped by power interruption.

The power supply circuit 25 has a built-in rectifier circuit (not shown) as charging means for rectifying the commercial AC of the commercial power supply. In a normal state, the DC output from the power supply circuit 25 is supplied to the electric equipment. At the same time as being supplied to the gas detector 21 and the gas detector 22, it is supplied as a charging current to the backup power source 23 via the normally closed contact 24a2. FIG. 1 shows an example in which the power supply circuit 25 is installed in a dangerous place, but the power supply circuit 25 may of course be installed in a non-dangerous place.

On the other hand, at the time of a power failure, the DC output of the backup power supply 23 is supplied to the electric equipment 21 and the gas detector 22, and the operation of the electric equipment 21 and the gas detector 22 at the time of the power failure is backed up. Here, the protection circuit unit 24b of the protection box 24 includes, for example, the gas detector 2
2 and a plunger that is attracted by the solenoid to open the normally closed contacts 24a1 and 24a2.

Next, the operation will be described. Now, in the state where the commercial power supply is not interrupted, if any kind of abnormality occurs and a dangerous atmosphere is generated in the two kinds of dangerous places, for example, due to the leakage of the flammable gas, the dangerous atmosphere caused by the leakage of the flammable gas is detected by the gas detector 22. Is detected, the protection circuit 24b of the protection box 24 is operated by the output of the gas detector 22 accompanying the detection of the dangerous atmosphere, and both normally closed contacts 24a1 and 24a2 of the protection box 24 are opened, so that the electrical equipment 2
1 is cut off, and the electric device 21 loses power, thereby preventing the electric device 21 from becoming an ignition source.

Here, both normally closed contacts 2 of the protection box 24
When the contacts 4a1 and 24a2 are opened, both normally closed contacts 24a1 and 24a2 are mechanically kept open. On the other hand, when the operator removes the cause of the dangerous atmosphere, the surroundings are removed. After confirming that there is no dangerous gas
This is done by a manual reset.

Further, in a state where the commercial power supply is stopped,
During a power outage, the gas detector 22 is supplied with power by the backup power supply 23. Therefore, even if any abnormality occurs during that time and a dangerous atmosphere is generated in the two hazardous locations, for example, due to a flammable gas leak, the gas detector 22 The dangerous circuit 22 detects the dangerous atmosphere due to the leakage of the flammable gas. The output of the gas detector 22 accompanying the detection of the dangerous atmosphere activates the protection circuit section 24b of the protection box 24, and the normally closed contacts 24a1, 24a2 is opened and electrical equipment 2
1 is cut off.

Since the normally closed contacts 24a1 and 24a2 can be reset only manually,
Even if the commercial power supply is restored while the power supply path to the electric device 21 is cut off by opening 4a1 and 24a2, the electric device 2
The cutoff state of the power supply path to 1 is maintained, and the electric device 21 does not become an ignition source and does not induce an explosion due to power recovery.

Therefore, according to the first embodiment, the normally closed contacts 24a1 and 24a2 of the protection box 24 are opened by the detection of the dangerous atmosphere by the gas detector 22, and the power supply path to the electric equipment 21 is changed. Since the electric device 21 can be cut off, the electric device 21 itself does not need to have a conventional expensive explosion-proof explosion-proof structure or internal pressure explosion-proof structure, and explosion-proof in two kinds of danger areas can be performed with an inexpensive configuration.

Further, even during a power failure, power is supplied to the gas detector 22 by the backup power supply 23, and a dangerous atmosphere generated during the power failure can be detected by the gas detector 22, so that the gas detector 22 at that time can be detected. With the output of 22, the two normally closed contacts 24a1 and 24a2 of the protection box 24 can be opened to maintain the power supply path to the electric device 21 in a cut-off state, thereby enabling more inexpensive and reliable explosion protection.

Further, even when the commercial power supply is restored, the normally closed contacts 24a1 and 24a2 are kept open unless manually restored, and the cutoff state of the power supply path to the electric equipment 21 is maintained. Electricity can prevent electric equipment 21 from becoming an ignition source and inducing an explosion.

Further, since the backup power supply 23 is composed of a secondary battery, it is not necessary to periodically check the remaining capacity as in the case where the backup power supply 23 is composed of a primary battery. Can be omitted.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIG.

In FIG. 2, reference numeral 30 denotes a partition wall which is installed on a floor surface 31 and partitions two types of danger areas from non-dangerous areas in a closed room. Reference numeral 33 denotes a recess formed in a part of the door 32 so as to be depressed inward, and reference numeral 34 denotes an electric device such as a control device for controlling a controlled device (not shown) which is installed in two kinds of danger areas partitioned by the partition wall 30. Equipment, 35 are gas detectors installed in two types of danger areas separated by a partition wall 30 to detect generation of a dangerous atmosphere in the two types of danger areas, and 36 is a backup for power failure provided in a recess 33 of a door 32. A backup power supply composed of a secondary battery such as a lead storage battery is provided in a two-risk area separated by a partition wall 30. The backup power supply 37 operates by the output of a gas detector 35 to shut off a power supply path to an electric device 34. Having protection A protection box as a step, 38 is a power supply circuit provided between the protection box 37 and the electric device 34 and the gas detector 35, 39 is an explosion-proof ventilation fan provided on the partition 30, and 40 is a recess of the door 32. 33 is a decorative plate covering the front surface of the panel 33.

Here, the basic configuration of the protection box 37 is the same as that of the protection box 24 of the above-described first embodiment (see FIG. 1).
It comprises a pair of normally-closed contacts provided in a current-carrying path connecting the electrical device 6 and the electric device 34, and a protection circuit unit that operates by the output of the gas detector 35 and opens both normally-closed contacts.

As in the case of the power supply circuit 25 of the first embodiment, the power supply circuit 38 has a built-in rectifier circuit as a charging means. And at the same time as being supplied to the gas detector 35, it is supplied as a charging current to the backup power supply 36 via the normally closed contact in the protection box 37.

Therefore, according to the second embodiment, since the backup power supply 36 is disposed in the recess 33 of the door 32, no special space is required for installing the backup power supply 36, and the backup power supply 36 is not required. 36 can be installed in a non-hazardous area without protruding outside, and the appearance can be prevented from being impaired. Also, the installation and wiring work of the backup power supply 36 can be easily performed.

Further, since the protection box 37 is formed in a two-risk area partitioned by the partition wall 30 with a pressure-resistant explosion-proof structure, when the protection box 37 must be installed in the two-risk area due to the installation space. To
By providing the protection box 37 with a flameproof structure, it can be installed in two types of hazardous places, and is particularly effective as a simple explosion-proof system inside buildings such as hotels with limited space.

The backup power supplies 23 and 36 are not limited to the above-described lead-acid batteries, but may be Ni-Cd
Of course, other secondary batteries such as batteries may be used. Further, the backup power supplies 23 and 36 may be primary batteries.

In the above embodiment, the electric equipment 2
1 and 34 have a built-in rectifier circuit, and a DC output from the rectifier circuit is supplied as a charging current to backup power supplies 23 and 36 via normally closed contacts of protection boxes 24 and 37 during a power outage, and a gas detector. Although the case where the drive current is supplied to the power supply 22 as described above has been described, a rectifier circuit as a charging means is provided in the protection boxes 24 and 37, and is supplied to the backup power supplies 23 and 36 as the charge current via the protection box 24 and 37, and the gas detection Needless to say, the drive current may be supplied to the devices 22 and 35.

Further, the configuration of the protection boxes 24 and 37 is not limited to the above, and it is possible to operate at least by the output of the gas detector to cut off the power supply path to the electric devices 21 and 34. Any configuration may be used.

Further, in the above-described second embodiment, the backup power supply 36 is provided in the recess 33 formed in the door 32, but the recess is formed in the partition 30 other than the door 32. Of course, it is good.

Further, the present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the gist of the present invention.

[0045]

As described above, according to the first aspect of the present invention, it is not necessary to make the electric equipment itself a conventional explosion-proof structure or an internal-pressure explosion-proof structure, so that explosion protection in two types of hazardous locations is not required. This can be performed with an inexpensive configuration.

According to the second aspect of the present invention, since the gas detector operates by being supplied with power from the backup power supply even at the time of a power failure, it can detect a dangerous atmosphere generated during the power failure. The protection means can be operated by the output of the gas detector at that time.

According to the third aspect of the present invention, since the backup power supply is always charged unless the commercial power supply is interrupted, the backup power supply is periodically charged, for example, when the backup power supply is constituted by a primary battery. It is not necessary to check the remaining capacity, and maintenance of the backup power supply is simplified.

According to the fourth aspect of the present invention, no special space is required for installing a backup power supply, and the backup power supply can be installed in a non-hazardous area without protruding outward. Does not impair.
Also, installation and wiring work can be easily performed.

According to the fifth aspect of the present invention, the protection means has a pressure-resistant explosion-proof structure, so that the protection means can be installed in two types of danger areas, particularly in buildings with limited space. It is effective as a system.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is a schematic diagram of a second embodiment of the present invention.

FIG. 3 is a schematic view of a conventional example.

FIG. 4 is a schematic view of another conventional example.

[Explanation of symbols]

 20, 30 Partition wall 21, 34 Electric equipment 22, 35 Gas detector 23, 36 Backup power supply 24, 37 Protection box (protection means) 32 Door 33 recess

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Yoshimichi Kiuchi 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi Inside Osaka Gas Co., Ltd. (72) Inventor Shojiro Oka 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi Inside Osaka Gas Co., Ltd. (72) Katsuteru Kitano 4-1-2, Hiranocho, Chuo-ku, Osaka City Inside Osaka Gas Co., Ltd. Inside the corporation

Claims (5)

[Claims] 1. A gas detector installed in two types of dangerous places where a dangerous atmosphere may be generated in an abnormal state, and an electricity installed in the two types of dangerous places operated by a detection output of the gas detector. A simple explosion-proof system in a hazardous area, comprising: protection means for interrupting a power supply path of a commercial power supply to equipment. 2. The simple gas detector according to claim 1, wherein the gas detector uses a commercial power supply as a power source during a non-power failure and a backup power supply provided for a backup during a power failure during a power failure. Explosion-proof system. 3. The simple explosion-proof system in a hazardous area according to claim 2, wherein the backup power supply is composed of a secondary battery, and a charging current is supplied by a charging unit using a commercial power supply as a power supply during a power outage. . 4. The danger according to claim 2, wherein the backup power supply is disposed in a recess formed in a partition wall between the two types of danger area and the non-danger area. Simple explosion-proof system in place. 5. The protection means has a pressure-resistant explosion-proof structure,
The simple explosion-proof system in a dangerous place according to any one of claims 1 to 4, wherein the system is installed in the two kinds of dangerous places.