An explosion-proof device includes a frame having a hollow shape, the frame housing an electrical component and a battery capable of supplying the electrical component with electric power. A protection device is configured to stop electric supply to the electrical component from the battery, if there is a risk of an explosive atmosphere entering the frame. The battery is housed in an explosion-proof container, within the frame, and thus it is possible to suppress damage to surroundings effectively even in case of ignition of an explosive atmosphere flowing into the frame by the battery.

TECHNICAL FIELD

The present disclosure relates to an explosion-proof device to be used in an explosive atmosphere.

BACKGROUND ART

During disaster prevention support works and building maintenance works in an explosive atmosphere, an explosion-proof device equipped with explosion-proof measures may be used to ensure industrial safety. Such an explosion-proof device is provided with explosion-proof measures, so that electric sparks and high-temperature parts of electrical components to be used do not behave as a source of ignition for the explosive atmosphere.

Explosion-proof devices to be used in actual works are practically required to undergo a test by the type test organization. Such a test is conducted according to, for instance, the Globally Coherent Guide to Explosion-proof 2008Ex, which is an international standard, and the terms used in this specification also comply with the standard unless otherwise stated (as described below, should the standard be revised in future, the terms shall be interpreted according to the revised standard within the scope of shared technique idea). For the specific practice of the standard, one may refer to Non-patent Document 1, for instance.

As an example of such a type of explosion-proof device, Patent Documents 1 and 2 disclose an explosion-proof structure for an industrial robot that enters an explosive atmosphere and performs works. Patent Document 1 discloses an explosion-proof structure which supplies air into a frame of a robot via an air pipe from an external air supply source, and thereby maintains the pressure inside the frame to be higher than the pressure of a surrounding explosive atmosphere, for preventing the explosive gas from entering the frame, where electrical components are situated. This document particularly discloses providing a protection monitoring device which blocks power supply to the electrical components inside the frame, if there is a risk of the explosive gas entering the frame due to a pressure decrease inside the frame. Furthermore, Patent Document 2 discloses an explosion-proof structure provided with an air tank for supplying air into a frame, mounted on an outer side of the frame, which is configured to block power supply to the electrical components inside the frame in the event of a pressure decrease inside the frame, similarly to Patent Document 1.

CITATION LIST

Patent Literature

Non-Patent Document 1: Nippon Electric Control Equipment Industries Association Explosion-proof Devices Committee, Guidebook to Explosion-proof Safety (Guide to Maintenance of Explosion-proofed Electric Devices for Facility Safety)

SUMMARY

Problems to be Solved

Such a type of explosion-proof device may include a battery as a power source, housed inside the frame. In Patent Documents 1 and 2, as described above, explosion-proof measures are taken by blocking power supply to the electrical components when there is a risk of explosive gas entering the frame. However, a battery charged with electrical energy is still in the frame at an entry of the explosive gas, and may make contact with the explosive gas and behave as a source of ignition. Thus, if the battery causes the explosive gas to ignite, explosion of the battery may damage the surroundings.

At least one embodiment of the present invention was made in view of the above problem, and an object is to provide an explosion-proof device having an explosion-proof structure capable of effectively suppressing damage to the surroundings due to explosion of a battery, in case an explosive gas enters the frame.

Solution to the Problems

(1) An explosion-proof device according to at least one embodiment of the present invention comprises: a frame having a hollow shape; an electrical component disposed in the frame; a battery being disposed inside the frame and being capable of supplying the electrical component with electric power; a protection device configured to stop electric supply to the electrical component from the battery, if a pressure inside the frame becomes not greater than a predetermined pressure value or if a pressure differential between inside and outside of the frame becomes not greater than a predetermined pressure differential value; and an explosion-proof container housing the battery, inside the frame.

With the above configuration (1), the battery disposed inside the frame for supplying electric power to the electrical components is housed in the explosion-proof container, and thereby it is possible to effectively suppress effects on the surroundings with the explosion-proof container, even in case of occurrence of explosion due to the battery behaving as the source of ignition at an entry of an explosive gas into the frame.

(2) In some embodiments, in the above configuration (1), the protection device includes a switching relay disposed in a power line between the battery and the electrical component, and configured to be capable of blocking electricity to the electrical component from the battery, and the explosion-proof container houses the switching relay, along with the battery.

With the above configuration (2), the switching relay, which may be a source of ignition for an explosive gas when being switched, is housed inside the explosion-proof container as described above, and thereby it is possible to effectively suppress effects on the surroundings even if an explosive atmosphere flows into the frame and explodes due to the switching relay.

(3) In some embodiments, in the above configuration (1) or (2), the battery includes a plurality of battery cells connected in series with one another, and the explosion-proof container houses a management device configured to manage the plurality of battery cells, along with the battery.

According to the above configuration (3), in a case where the management device is provided to manage a plurality of battery cells that constitute a battery, the management device is housed in the explosion-proof container alongside with the battery. Such a management device is supplied with some power on a constant basis to manage the state of the plurality of battery cells daily. Thus, when an explosive gas enters the frame, the management device is likely to behave as a source of ignition due to the continuous power supply to the management device, despite the protection device blocking the power supply from the battery to the electrical components. However, with the management device being housed in the explosion-proof container alongside with the battery, it is possible to reduce effects on the surroundings even in case the management device behaves as a source of ignition and causes explosion.

(4) In some embodiments, in any one of the above configurations (1) to (3), the explosion-proof container comprises a pressure-resistant explosion-proof container.

With the above configuration (4), the explosion-proof container for housing the battery comprises the pressure-resistant explosion-proof container, and thereby it is possible to realize an explosion-proof structure that withstands explosion of the battery or an internal explosive gas without being damaged, wherein all joints or structural openings of the container do not allow fire to reach the external explosive atmosphere.

(5) In some embodiments, in any one of the above configurations (1) to (4), the frame comprises an internal-pressure explosion-proof container.

With the above configuration (5), with the frame comprising the internal-pressure explosion-proof container, it is possible to isolate the electrical components and the battery, which may behave as a source of ignition, from an explosive atmosphere.

(6) In some embodiments, in any one of the above configurations (1) to (5), the explosion-proof container comprises a safety-enhanced explosion-proof container.

With the above configuration (6), the explosion-proof container housing the battery comprises the safety-enhanced explosion-proof container, and thereby it is possible to enhance the safety electrically, mechanically, or thermally, and thus to prevent breakdown such as insulation failure, contact failure, and disconnection, thereby effectively suppressing electrical ignition and abnormally high temperature which may become a source of ignition.

(7) In some embodiments, in any one of the above configurations (1) to (6), the explosion-proof device comprises a traveling body including a motor mounted thereto as a power source for traveling, the motor being capable of being driven by electric power supplied from the battery.

With the above configuration (7), the above described explosion-proof structure is applied to a traveling body that enters an explosive atmosphere and performs works. With such an explosion-proof structure, only the battery that may become a source of ignition in case of an entry of an explosive gas into the frame is housed in the explosion-proof container, and thus it is possible to avoid a considerable increase in the size and weight of the explosion-proof container. Accordingly, it is possible to effectively reduce the size and weight of the traveling body, and to achieve both of good explosion-proof performance and traveling performance.

(8) In some embodiments, in any one of the above configurations (1) to (6), the explosion-proof device comprises a control panel powered by the battery serving as a normal or emergency power source.

With the above configuration (8), it is possible to apply the above protection-proof structure to a control panel fixedly situated in an explosive atmosphere.

Advantageous Effects

According to at least one embodiment of the present invention, it is possible to provide the explosion-proof device having an explosion-proof structure capable of effectively suppressing damage to the surroundings due to explosion of the battery, in case an explosive atmosphere enters the frame.

DETAILED DESCRIPTION

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It is intended, however, that unless particularly specified, dimensions, materials, shapes, relative positions and the like of components described in the embodiments shall be interpreted as illustrative only and not intended to limit the scope of the present invention.

FIG. 1is a schematic configuration diagram of an explosion-proof device10according to at least one embodiment of the present invention, andFIG. 2is a modified example of the peripheral configuration of the battery24shown inFIG. 1.

The explosion-proof device10is an industrial robot capable of entering an explosive atmosphere by driving itself and performing or supporting various works such as disaster prevention support works and building maintenance works. Environments of such works include an extensive range of fields that may generate an explosive gas, such as oil and chemical plants, manufacture/storage/handling facilities for hazardous materials such as flammable liquids, painting facilities, work sites using solvents, high-pressure gas facilities, and fuel cell related facilities.

The explosion-proof device10is a traveling body including a frame12having a hollow shape and constituting a body, and being capable of traveling with four wheels16respectively disposed on the right-front, left-front, right-rear, and left-rear sections of the frame12. A motor18is housed in the frame12, for serving as a power source for traveling. A driving force from the motor18is transmitted to the wheels16, so that the wheels16can travel on a field.

The explosion-proof device10includes a motor18capable of being driven by electric power supplied from a battery24described below, as a power source for traveling. The motor18has an output shaft connected to the wheels16via a speed reducer20. The output of the motor18is transmitted to the wheels16via the speed reducer20, and thereby traveling is realized.

It should be noted that, instead of the wheels16, another traveling unit such as a crawler may be employed.

The frame12having a hollow shape houses electrical components including the above described motor18. In the present embodiment, in particular, the frame12is configured as an internal-pressure explosion-proof device having an internal-pressure explosion-proof structure. In the internal-pressure explosion-proof structure, electrical components or parts that may behave as a source of ignition for an explosive gas are housed inside a container having a predetermined specification, and inert gas (protection gas) such as air and nitrogen is sent and pressurized into the container, thereby isolating the electrical components or the parts from an external explosive atmospheres.

The detailed specification of the internal-pressure explosion-proof structure complies with the Globally Coherent Guide to Explosion-proof 2008Ex (specifically, see the above Non-patent Document 1). Furthermore, should the guide be revised in future, the terms used in this specification shall also be interpreted according to the revised content.

The interior of the frame12is isolated from the exterior (explosive atmosphere), and thereby the frame12is maintained under an air-tight state. The frame12is filled with inert gas in advance, before the explosion-proof device10enters an explosive atmosphere.

While the frame12may have a small gap at, for instance, a part where a drive shaft connecting the wheel16and the reducer20is inserted through, in this embodiment, an air-tight state is ensured for such a gap with a seal member22disposed thereon.

Furthermore, inert gas inside the frame12is enclosed so that the pressure inside the frame12is higher than the pressure outside the frame12. In the frame12, such an internal-pressure explosion-proof structure prevents an explosive gas from entering the frame12from the surrounding explosive atmosphere.

The explosion-proof device10may include a gas supply device for filling the inside of the frame12with inert gas. For instance, the explosion-proof device10may be configured to be capable of supplying the frame12with gas via an air pipe from an air source provided independently outside the explosion-proof device10, as disclosed in Patent Document 1, or supplying the inside of the frame12with gas from an air tank storing air in advance, the air tank being mounted to the explosion-proof device10, as disclosed in Patent Document 2. Furthermore, the explosion-proof device10may include a discharge mechanism for discharging gas inside the frame12, thus being capable of adjusting the internal pressure of the frame12.

The frame12houses, as electrical components besides the above described motor18, a battery24for supplying electric power, a controller26for performing various controls on the explosion-proof device10, a driver28for driving the motor18, a pressure detection part30capable of detecting at least one of the internal pressure or the external pressure of the frame12, an explosion-proof logic circuit32for performing an explosion-proof control, and a receiver-transmitter34for receiving and transmitting various types of information with an external unit.

Although not shown inFIG. 1, the explosion-proof device10may include, in addition to the above described constituent elements, various devices corresponding to the content of work, such as a robot arm, a winch device, a lighting device, and an imaging device (camera), and the electrical components housed in the frame12may include various components for operating such a robot arm.

The battery24is an electric storage device for storing electric power to be supplied to the electrical components housed in the frame12, and is connected to the controller26, the driver28, the explosion-proof logic circuit32, and the receiver-transmitter34, via power lines L1, L2, L3, and L4, respectively, so as to be capable of supplying electric power to the controller26, the driver28, the explosion-proof logic circuit32, and the receiver-transmitter34.

In the present embodiment, the battery24comprises a lithium-ion secondary battery having a relatively large energy density. The battery24comprises a plurality of secondary battery cells24a,24b,24c, and so on, connected in series. As shown inFIG. 2, a management device (also known as battery management unit, or BMU)36may be provided to manage a variety of state parameters of the plurality of secondary battery cells24a,24b,24c, . . . , (e.g. charge amount, electric-current amount, temperature). The management device36monitors the state parameters of the respective secondary battery cells24a,24b,24c, . . . , and determines the state abnormality on the basis of the result of monitoring, then transmitting the determination result to the controller26.

The management device36obtains electric driving power from the battery24to be managed. In other words, the power supply route to the management device36is provided independently from the above described power lines L1, L2, L3, and L4. Thus, even if the power lines L1, L2, L3, and L4are blocked by the explosion-proof logic circuit32described below, the management device36can continue to receive power supply from the battery24, and can continue management of the battery24.

The controller26is a control unit for performing various controls of the explosion-proof device10, and functions by obtaining electric power from the battery24via the power line L1. The controller26generates control signals for realizing various operations of the explosion-proof device10on the basis of a predetermined program stored in advance in a storage device (not shown) such as a memory, and sends commands to the constituent elements of the explosion-proof device10to perform controls.

The driver24is a driving unit for driving the motor18, in response to the content of commands from the controller26. For instance, the driver24adjusts the control electric current of the motor18so as to correspond to the control signals obtained from the controller26, and thereby controls the driving state of the motor18and realizes traveling of the explosion-proof device10.

The pressure detection part30detects at least one of the internal pressure or the external pressure of the frame12. As described above, while the explosion-proof device10has an explosion-proof structure realized by setting the internal pressure of the frame12to be higher than the external pressure of the frame12, the internal pressure of the frame12may decrease due to some reason, causing an explosive gas to enter. The pressure detection part30detects at least one of the internal pressure or the external pressure of the frame12, and thereby performs pressure detection required to determine whether such an entry of an extensive gas could occur. For instance, the pressure detection part30may detect the differential pressure between the internal pressure and the external pressure of the frame12, thereby detecting whether there is a risk of an explosive atmosphere entering the inside of the frame12. In a case where an appropriate value is set in advance for the internal pressure of the frame12, the pressure detection part30may detect only the internal pressure of the frame12to perform the determination (in the latter case, there is no need to detect the external pressure of the frame12).

While the present embodiment described herein includes a pressure sensor as the pressure detection part30, which handles detection results as electrical signals, a pressure switch may be employed instead, which mechanically performs switching according to a pressure value.

The explosion-proof logic circuit32performs an explosion-proof control on the basis of a detection result of the pressure detection part30. Herein, a protection circuit40including a switching relay38capable of being turned on/off is disposed in the power lines for supplying electric power to the electrical components from the battery24, and if it is determined that there is a risk of an explosive gas entering the frame12on the basis of the detection result of the pressure detection part30(i.e., if it is detected that the inside of the frame12has a lower pressure than the outside), the explosion-proof logic circuit32performs a switching control with the switching relay38, thereby blocking power supply to the electrical components.

The switching relay38is a relay device that functions as an interlock breaker. Normally, the switching relay38is set to be in a closed state, as an initial state, so that electric power from the battery24is supplied to the electrical components. When the state of the switching relay38is switched to an open state by the explosion-proof logic circuit32, electric supply to the electrical components can be blocked. When the protection circuit40is operated by the explosion-proof logic circuit32, electric supply from the battery24stops, and thus it is possible to effectively prevent occurrence of explosion due to an electrical component behaving as a source of ignition, at an entry of explosive gas into the frame12.

Moreover, a predetermined display may be shown to inform an operator when the protection circuit40is operated by the explosion-proof logic circuit32.

The receiver-transmitter34is a communication device configured to be capable of performing wireless communication with a server42installed in a base station in a non-explosive atmosphere (outside an explosive atmosphere). The receiver-transmitter34includes an antenna35for receiving and transmitting radio waves for communication, disposed inside a radio-wave transparent air-tight dome, and performs wireless communication with an antenna43provided for the server42. The server42includes an operation device44an operator can operate, and a receiver-transmitter46capable of receiving and transmitting command signals from the operation device44via the antenna43. Accordingly, the explosion-proof device10can be operated remotely by an operator in a non-explosive atmosphere sending commands to the explosion-proof device10.

While the communication between the explosion-proof device10and the server42is wireless in the present embodiment, wire communication using a communication optical fiber may be applied, for instance. Furthermore, for the explosion-proof device10, wire connection with the outside via an alternative communication optical fiber may be provided alongside with wireless connection, in case of malfunction of the receiver-transmitter34. In this case, it is possible to communicate with the outside via the communication optical fiber even if the receiver-transmitter34breaks down, while it is also possible to continue communication in case of disconnection of the communication optical fiber.

Herein, the battery24disposed inside the frame12is further housed in an explosion-proof container50. In the present embodiment, in particular, the explosion-proof container50is configured as an pressure-resistant explosion-proof container having an pressure-resistant explosion-proof structure. The pressure-resistant explosion-proof structure is an explosion-proof structure comprising a container that withstands internal explosion due to an explosive gas having entered the container without being damaged, wherein all joints or structural openings of the container do not allow fire to reach the external explosive atmosphere.

According to the above described Non-Patent Document 1, such a pressure-resistant explosion-proof container is required to satisfy the following conditions. (i) The container has a strength that can withstand internal explosion sufficiently. The container is designed to have a strength that can withstand the explosive pressure in case explosion occurs inside the container. (ii) Flame having an ignition capacity does not escape through the joint surfaces forming the container. The joint surfaces of the container have “depth of gap” and “gap” such that high-temperature gas or flame is sufficiently cooled when being discharged outside through the gap in case of internal explosion, which prevents an external explosive gas from catching fire. (iii) The allowable temperature of the outer surface of the container, or the maximum surface temperature does not exceed a predetermined value. With regard to the ignition level and the temperature class specified in accordance with the ignition temperature of an explosive gas, the allowable temperature and the maximum surface temperature of the explosion-proof electric device are set so as not to exceed the specified value.

The detailed specification of the pressure-resistant explosion-proof structure complies with the Globally Coherent Guide to Explosion-proof 2008Ex and the like (see the above Non-patent Document 1 for details). Furthermore, should the guide be revised in future, the terms used in this specification shall also be interpreted according to the revised content.

Accordingly, the battery24disposed inside the frame12for supplying electric power to the electrical components is housed in the explosion-proof container50, and thereby it is possible to effectively suppress effects on the surroundings with the explosion-proof container50, even in case of occurrence of explosion due to the battery24behaving as the source of ignition at an entry of an explosive gas into the frame12.

In the present embodiment, in particular, the explosion-proof container50houses the switching relay38forming the protection circuit40with the battery24. The switching relay38may be a source of ignition for an explosive gas if a switching operation is performed while electric power is supplied. Thus, with the switching relay38, which may be a source of ignition, housed inside the explosion-proof container50as described above, it is possible to effectively suppress effects on the surroundings even if the switching relay38ignites an explosive atmosphere in the frame12to cause explosion.

Furthermore, as shown inFIG. 2, the explosion-proof container50may house the management device36along with the battery24. As described above, the management device36is supplied with power independently from the power lines for the other electrical components to manage the state of the battery24on a constant basis, and the management device36is continuously supplied with power even if the protection device40blocks electric supply to the electrical components. Accordingly, if an explosive gas enters the frame12during operation of the protection device40, the management device36receiving continuous electric supply may become a source of ignition. Thus, with the management device36housed inside the explosion-proof container50with the battery24as described above, it is possible to effectively suppress effects on the surroundings even if the management device36becomes a source of ignition for an explosive atmosphere that has entered the frame12.

With such an explosion-proof structure, only the constituent elements (battery24and management device36) that may become a source of ignition in case of an entry of an explosive gas into the frame12are housed in the explosion-proof container50, and thus it is possible to avoid a considerable increase in the size and weight of the explosion-proof container50. Accordingly, it is possible to effectively reduce the size and weight of the explosion-proof device10, and to achieve both of good explosion-proof performance and traveling performance as a traveling body.

Furthermore, the explosion-proof container50comprises a pressure-resistant explosion-proof container in the above embodiment, for the battery24comprises a lithium-ion secondary battery having a high energy density. Nevertheless, another type of explosion-proof container50may be employed corresponding to the specification of the battery24to be housed. For instance, if the battery24does not include a source of ignition other than a fuel cell, like the above management device36, the explosion-proof container50may comprise a safety-enhanced explosion-proof container. Normally, a safety-enhanced explosion-proof container has a smaller size and weight than the above described pressure-resistant explosion-proof container, and thus it is possible to reduce the size and weight of the explosion-proof device10by suitably selecting a safety-enhanced explosion-proof container in accordance with the specification of the battery24, and to improve the traveling performance.

Next, with reference toFIG. 3, another embodiment will be described.FIG. 3is a schematic configuration diagram of an explosion-proof device10′ according to another embodiment. InFIG. 3, the same constituent elements as those inFIGS. 1 and 2are associated with the same reference numerals, and not described again unless necessary.

The explosion-proof device10′ is a control panel provided fixed in an explosion-proof atmosphere, for controlling a pressure-resistant explosion-proof motor60to be controlled, disposed in an explosive atmosphere. Accordingly, the explosion-proof device10′ is different from the above described explosion-proof device10in that the explosion-proof device10′ is a non-traveling body fixed on a field.

The explosion-proof device10′ has an external power source (e.g. commercial AC source)62disposed in a non-explosive atmosphere as a normal power source. The external power source62supplies electric power to the electrical components housed in the frame12via a normal power line L5. The normal power line L5is connected to an AC/DC converter64which is one of the electrical components housed in the frame12, and the AC/DC converter is configured to convert AC power supplied from the external power source62to DC power. The DC power converted by the AC/DC converter64is supplied to the controller26serving as a control unit for the explosion-proof device10′.

Herein, the explosion-proof device10′ includes a battery24housed in the frame12, as an emergency power source. The battery24stores DC power in advance, and is connected to the controller26via an emergency power line L6. Switching relays66,68are disposed in the normal power line L5and the emergency power line L6, respectively. The switching relay66of the normal power line L5is initially set in a closed state, and the switching relay68of the emergency power line L6is set in a normal-open state. Accordingly, the controller26is normally supplied with power from the external power source64.

While the external power source62is used as a normal power source and the battery24is used as an emergency power source in the present embodiment, the battery24may be used as a normal power source and the external power source62as an emergency power source. Alternatively, a third power source may be provided as a normal or emergency power source.

On the other hand, when an abnormality occurs (e.g. the external power source62falls into a shutdown state), the controller26switches the switching relay66of the normal power line L5to an open state and the switching relay68of the emergency power line L6to a closed state, thereby switching the power supply source for the controller26to the battery24from the external power source62. Accordingly, even if an abnormality occurs in the external power source62, it is possible to continue operation of the explosion-proof device10′ by using the battery24housed inside the frame12as an emergency power source.

Furthermore, an operation part70that an operator can operate is disposed outside the frame12, and the content of operation of the operation part70is converted into electric signals by a switch74inside the frame12, before being sent to the controller26. The controller26receives the electric signals sent from the switch74to determine the operation capability of the operator, and sends control signals based on the content to a driver28. The driver controls driving current of the pressure-resistant explosion-proof motor60to be controlled on the basis of the control signals obtained from the controller26.

The explosion-proof device10′ is provided with a display76for displaying the content of operation by the operator and the content of control by the controller26. The display76is configured to be visible to the operator outside the frame12, via a tempered glass78disposed on the window section of the frame12.

Similarly to the embodiment ofFIG. 1, the frame12is filled with inert gas, thus being configured as an internal-pressure explosion-proof container capable of preventing an explosive gas from entering the frame12. The internal pressure, or the differential pressure between the inside and the outside of the frame12is detected by the pressure detection part30, and if it is determined on the basis of the detection result that there is a risk of an explosive gas entering the frame12, the explosion-proof logic circuit32switches the switching relay68of the emergency power line L6to an open state, thereby blocking power supply from the battery24. Accordingly, even if an explosive gas flows into the frame12, it is possible to effectively prevent an electrical component supplied with electric power from the battery24from becoming a source of ignition.

The battery24disposed inside the frame12is further housed in an explosion-proof container50. In the present embodiment, in particular, the explosion-proof container50is configured as a pressure-resistant explosion-proof container having a pressure-resistant explosion-proof structure. However, similarly toFIG. 1, another suitable type of explosion-proof container can be employed corresponding to the specification of the battery such as the capacity. Accordingly, the battery24disposed inside the frame12for supplying electric power to the electrical components is housed in the explosion-proof container50, and thereby it is possible to effectively suppress effects on the surroundings with the explosion-proof container50, even in case of occurrence of explosion due to the battery24behaving as the source of ignition in case an explosive gas enters the frame12.

Furthermore, the explosion-proof container50houses the switching relays66,68respectively disposed in the normal power line L5and the emergency power line L6, along with the battery24. The switching relays66,68may be a source of ignition for an explosive gas when being switched. Thus, with the switching relays66,68, which may be a source of ignition, housed inside the explosion-proof container50as described above, it is possible to effectively suppress effects on the surroundings even if the switching relays66,68ignite an explosive atmosphere in the frame12to cause explosion.

In the present embodiment, the explosion-proof container50houses the management device36along with the battery24, similarly toFIG. 2.

Accordingly, also in the explosion-proof device10′ fixed in an explosive atmosphere, the battery24disposed inside the frame12for supplying electric power to the electrical components is housed in the explosion-proof container50, and thereby it is possible to effectively suppress effects on the surroundings with the explosion-proof container50, even in case of occurrence of explosion due to the battery24behaving as the source of ignition in case an explosive gas enters the frame12.

As described above, according to at least one embodiment of the present invention, it is possible to provide the explosion-proof device10having an explosion-proof structure capable of effectively suppressing damage to the surroundings due to explosion of the battery24, in case an explosive atmosphere enters the frame12.

INDUSTRIAL APPLICABILITY

The present disclosure can be applied to an explosion-proof device to be used in an explosive atmosphere.

DESCRIPTION OF REFERENCE NUMERALS