JP2002353653A - Terminal box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a terminal box the weight of which does not increase even when the size of a plant increases. SOLUTION: A gas supply device 7 which supplies clean air or an inert gas is provided on the outside of this terminal box 1, and a gas supply pipe 3 is led into this box 1 from the device 7. A solenoid valve 2 is attached to the gas supply pipe 3 led into this box 1 so that the clean air or inert gas may be discharged into the box 1 when the valve 2 is opened. In addition, an energized state monitoring device 4 is provided in this box 1 so as to always monitor whether the inside of the box 1 is in an energized state. When the inside of the box 1 is not in the energized state, the valve 2 is opened and the clean air or inert gas is discharged into the box 1. When electric power is supplied to the inside of the box 1 and the inside of the box 1 is energized, the valve 2 is immediately closed and the supply of the clean air or inert gas into the box 1 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal box used in an atmosphere where flammable gas or flammable liquid vapor is present and in which electric equipment is housed.

[0002]

2. Description of the Related Art A terminal box used in an atmosphere where flammable gas or flammable liquid vapor exists, such as in a petroleum refining, petrochemical, or chemical synthesis plant, has a risk of explosion or fire due to electric sparks or the like. Therefore, it is necessary to classify hazardous areas according to the frequency and time at which an explosive atmosphere is generated, and to provide an explosion-proof structure corresponding to the classification.

[0003]

However, as the size of the plant increases, the number of devices that need to be housed in the terminal box also increases, so that the terminal box tends to increase in size. In order to maintain a predetermined strength even when the terminal box is enlarged as described above, the thickness of the box must be increased and the weight of the box increases.

[0004] The present invention has been proposed to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a terminal box which does not increase in weight even if the plant is enlarged. .

[0005]

In order to achieve the above object, the present invention is to automatically scavenge the inside of a terminal box with clean air or a nonflammable gas before electricity is applied to the terminal box. Is made possible. That is, the invention according to claim 1 accommodates a predetermined electric device inside,
In a terminal box used in an explosive atmosphere while wiring and connecting the electric device to the outside, the terminal box includes an energization state monitoring unit that constantly monitors whether the inside of the terminal box is energized, A gas supply pipe for supplying clean air or an inert gas from the outside into the terminal box is provided, and a first solenoid valve controlled to be opened and closed by the power supply state monitoring means is attached to the gas supply pipe. The first electromagnetic valve is configured to be closed when the inside is in an energized state.

According to the first aspect of the present invention, power is supplied to the terminal box by providing the solenoid valve which is closed when the terminal box is energized. Up to this point, clean air or non-combustible gas can be supplied into the terminal box. Lowering the risk of explosion. Further, since the flammable gas concentration can be reduced, it is possible to use ordinary equipment that is not an explosion-proof type. Further, since the solenoid valve is closed at the same time when power is supplied to the terminal box, a large amount of clean air or noncombustible gas is not always consumed.

According to a second aspect of the present invention, in the terminal box according to the first aspect, the gas supply pipe is branched into two parts in the terminal box, and the first solenoid valve is disposed on one of the branches and the other. Is provided with a flow control valve. According to the invention as set forth in claim 2 having the above-described configuration, a small amount of clean air or incombustible gas is constantly discharged into the terminal box via the flow control valve, and the pressure inside the terminal box is compared with that outside. Therefore, even if the degree of sealing of the terminal box is reduced, intrusion of flammable gas can be prevented.

According to a third aspect of the present invention, in the terminal box according to the first aspect, the gas supply pipe is branched into two in the terminal box, one of which is provided with the first solenoid valve, and the other of which is provided. And a second solenoid valve controlled to be opened and closed from outside the terminal box. According to the third aspect of the invention having the above configuration, the pressure inside the terminal box is made higher than that outside by appropriately opening and closing the second solenoid valve that is opened and closed from the outside. Therefore, even if the degree of sealing of the terminal box is reduced, intrusion of flammable gas can be prevented.

According to a fourth aspect of the present invention, in the terminal box of the third aspect, a flow control valve is connected in series to the second solenoid valve. According to the invention as set forth in claim 4 having the above-described configuration, by appropriately opening and closing the second solenoid valve whose operation is controlled from the outside, the pressure inside the terminal box can be made higher than that outside. Therefore, even if the degree of sealing of the terminal box is reduced, intrusion of flammable gas can be prevented. In addition, since a small amount of clean air or incombustible gas is discharged into the terminal box via the flow control valve, pressure fluctuations to the supply source of clean air or the like due to opening and closing of the second solenoid valve can be reduced.

According to a fifth aspect of the present invention, in the terminal box according to the first aspect, the gas supply pipe is bifurcated in the terminal box, and the first solenoid valve is provided on one of the two, and the other is provided on the other. A second electromagnetic valve is provided, and both electromagnetic valves are configured to be opened and closed by the conduction state monitoring means. According to the invention as set forth in claim 5 having the above-described configuration, the second solenoid valve that is “open” when energized is controlled to be opened and closed by the same energization state monitoring means as the first solenoid valve. Before being powered into
The first solenoid valve is opened, the second solenoid valve is closed, and the inside of the terminal box is scavenged with clean air or nonflammable gas. In addition, the first solenoid valve is automatically closed simultaneously with power supply,
Instead, the second solenoid valve is opened, and the pressure inside the terminal box can be increased as compared with the outside. Therefore, even if the degree of sealing of the terminal box is reduced, intrusion of flammable gas can be prevented.

According to a sixth aspect of the present invention, there is provided a terminal box in which a predetermined electric device is housed, the electric device is connected to the outside by wiring, and the terminal box is used in an explosive atmosphere. A power supply state monitoring means for constantly monitoring whether the inside of the terminal box is in a power supply state, and a gas supply pipe for supplying clean air or an inert gas from the outside into the terminal box. A three-way solenoid valve that is controlled to be opened and closed by the energization state monitoring means is mounted, one of which is opened when the terminal box is in a non-energized state and opened in the terminal box, and the other is used for flow rate adjustment. A valve is provided, and is configured to be opened when the terminal box is in an energized state.

According to the sixth aspect of the present invention, since the three-way solenoid valve is controlled to be opened and closed by the conduction state monitoring means, the three-way solenoid valve is supplied before the power is supplied to the terminal box. When the power is not supplied, the "open" side is opened, and when the power is supplied, the "open" side is closed, and the inside of the terminal box is scavenged with clean air or nonflammable gas. When power is turned off, the “open” side automatically closes when power is turned off, and instead opens when the power is turned on.This allows the internal pressure of the terminal box to be higher than that of the outside. Even if the degree of sealing is reduced, intrusion of combustible gas can be prevented.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a terminal box according to the present invention (hereinafter, referred to as an embodiment) will be described below with reference to the drawings. In each embodiment, the same members are denoted by the same reference numerals, and description thereof will be omitted.

(1) First Embodiment FIG. 1 is a diagram showing a configuration of a terminal box according to a first embodiment of the present invention. That is, predetermined electric equipments 5 are housed in the semi-sealed terminal box 1, and are connected to the outside by the wiring 6. A gas supply device 7 that is a supply source of clean air or an inert gas is provided outside the terminal box 1, and a gas supply pipe 3 is provided from the gas supply device 7 into the terminal box 1. . An electromagnetic valve 2 is attached to a gas supply pipe 3 introduced into the terminal box 1, and is connected so as to discharge clean air or an inert gas into the terminal box 1 when the valve is opened. .

In the terminal box 1, a power monitoring device 4 is provided.
Is provided to constantly monitor whether or not the inside of the terminal box 1 is in the energized state. Then, when the inside of the terminal box 1 is not in the energized state by the energized state monitoring device 4,
The electromagnetic valve 2 is opened so that clean air or inert gas is discharged into the terminal box 1. On the other hand, when the power is supplied to the terminal box 1 and the terminal box 1 is energized, the solenoid valve 2 is closed immediately and the supply of clean air or inert gas into the terminal box 1 is stopped.

In this embodiment having the above-described configuration, the solenoid valve 2 is opened until power is supplied to the terminal box 1, and clean air or inert gas supplied from the outside is supplied to the terminal box 1. It is released inside. Thus, even if an explosive gas or the like enters the inside of the terminal box 1 while the power supply is stopped, the explosive gas in the terminal box 1 is supplied by flowing clean air or an inert gas for a sufficient time. Etc. can be scavenged to the outside. That is, the terminal box 1 can be scavenged without supplying power to the terminal box 1.

According to the Fire Service Law, if the volume of clean air or inert gas to be scavenged becomes five times or more that of the terminal box 1, the inside of the terminal box 1 can be regarded as a safe space without explosive gas. And Therefore, it is also possible to measure the amount of clean air or inert gas supplied to the terminal box 1 and confirm that the volume of the terminal box has become five times or more, and then supply current to the terminal box. it can.

As described above, in this embodiment, by providing the solenoid valve 2 that closes the valve at the same time as the inside of the terminal box 1 is energized, the inside of the terminal box 1 is made a safe space. Since electric power is supplied for the first time, it is not necessary that the electric devices 5 housed in the terminal box 1 be explosion-proof devices. Further, since the terminal box 1 itself does not need to be explosion-proof, it is not necessary to increase the thickness of the terminal box 1 and the weight does not increase. Further, since the solenoid valve 2 is closed together with the power supply, clean air or non-combustible gas is not always consumed in large quantities.

(2) Second Embodiment This embodiment is obtained by further improving the first embodiment. That is, FIG. 2 is a diagram showing the configuration of the second embodiment of the terminal box according to the present invention, in which the gas supply pipe 3 arranged in the terminal box 1 from the gas supply device 7 branches in the terminal box 1. Thus, branch pipes 3a and 3b are formed. Also, one branched pipe 3a is provided with the same electromagnetic valve 2 as in the first embodiment, and the other branched pipe 3b is provided with a flow regulating valve 8.

In the terminal box 1, an energization state monitoring device 4 is provided similarly to the first embodiment, and is configured to constantly monitor whether or not the terminal box 1 is energized. . When the inside of the terminal box 1 is not in a conducting state, the solenoid valve 2 is opened by the conducting state monitoring device 4 so that clean air or an inert gas is discharged into the terminal box 1. I have. Further, it is configured such that clean air or inert gas is always discharged into the terminal box 1 via the flow rate control valve 8. The other configuration is the same as that of the first embodiment, and the description is omitted.

In this embodiment having the above-described configuration, the solenoid valve 2 is kept open until power is supplied to the terminal box 1, and clean air or inert gas supplied from the outside is supplied to the terminal box 1. It is configured to be released inside. Further, it is configured such that clean air or inert gas is always discharged into the terminal box 1 via the flow rate control valve 8.

Thus, even when the power supply is stopped, the terminal box 1
Even if an explosive gas or the like has entered the inside of the terminal box, the explosive gas or the like in the terminal box 1 can be scavenged to the outside by flowing clean air or an inert gas for a sufficient time. That is, the terminal box 1 can be scavenged without supplying power to the terminal box 1. Further, in the present embodiment, since clean air and inert gas are always discharged into the terminal box 1 via the flow rate regulating valve 8, the pressure inside the terminal box 1 can be increased as compared with the outside. Therefore, even if the degree of sealing of the terminal box 1 is lowered, intrusion of combustible gas can be prevented.

As described above, in the present embodiment, the solenoid valve 2 for closing the valve is provided at the same time as the inside of the terminal box 1 is energized, and the flow rate adjusting valve 8 is provided. Terminal box 1
Can be further lightened and simplified.

(3) Third Embodiment This embodiment is a modification of the second embodiment. That is, FIG. 3 is a diagram showing a configuration of a third embodiment of the terminal box according to the present invention, and one of the branched pipes 3a is provided with the same electromagnetic valve 2 as in the first embodiment, A second solenoid valve 9 whose opening and closing operation is controlled by a control power supply 10 arranged outside the terminal box 1 is provided on the other branch pipe 3b.
Is provided. The other configuration is the same as that of the second embodiment, and the description is omitted.

In this embodiment having the above-described structure, the solenoid valve 2 is kept open until power is supplied to the terminal box 1, and clean air or inert gas supplied from the outside is supplied to the terminal box 1. It is configured to be released inside. Further, in the present embodiment, by appropriately opening and closing the second solenoid valve 9 from the outside, clean air and inert gas are released into the terminal box 1, so that the pressure inside the terminal box 1 is reduced to the outside. Terminal box 1
Even if the degree of sealing is reduced, intrusion of combustible gas can be prevented.

As described above, in the present embodiment, the electromagnetic valve 2 for closing the valve is provided at the same time as the inside of the terminal box 1 is energized, and the second opening and closing control is appropriately performed from the outside.
By providing the electromagnetic valve 9, the degree of sealing of the terminal box 1 can be reduced, and the terminal box 1 can be further reduced in weight and simplified.

(4) Fourth Embodiment This embodiment is a further modification of the third embodiment. That is, FIG. 4 is a diagram showing a configuration of a fourth embodiment of the terminal box according to the present invention, and one of the branched pipes 3a is provided with the same electromagnetic valve 2 as in the first embodiment, A second solenoid valve 9 and a flow control valve 8 whose opening and closing operations are controlled by a control power supply 10 arranged outside the terminal box 1 are connected in series to the other branch pipe 3b. The other configuration is the same as that of the third embodiment, and the description is omitted.

In this embodiment having the above-described configuration, similarly to the third embodiment, the scavenging of explosive gas and the like and the pressure inside the terminal box 1 can be increased as compared with the outside. . Furthermore, in the present embodiment, a small amount of clean air or non-combustible gas can be discharged into the terminal box 1 via the flow control valve 8, so that the second solenoid valve 9
The pressure fluctuation to the supply source of the clean air or the like due to the opening and closing of can be reduced.

As described above, in the present embodiment, the solenoid valve 2 for closing the valve is provided at the same time as the inside of the terminal box 1 is energized, and the second opening and closing control is appropriately performed from the outside.
By providing the solenoid valve 9 and the flow control valve 8, the degree of sealing of the terminal box 1 can be reduced, the terminal box 1 can be further reduced in weight and simplicity, and the cleaning by opening and closing the second solenoid valve 9 can be achieved. Pressure fluctuations to the supply source of fresh air or the like can also be reduced.

(5) Fifth Embodiment This embodiment is a further improvement of the third and fourth embodiments. FIGS. 5 and 6 show a fifth embodiment of the terminal box according to the present invention. It is a figure showing composition of a 5th embodiment. That is, in the present embodiment, the opening / closing control of the second solenoid valve 9 shown in the third embodiment is configured to be performed by the energization state monitoring device 4 similarly to the solenoid valve 2. The opening and closing of the second solenoid valve 9 is opened when the inside of the terminal box 1 is energized, contrary to the opening and closing control of the solenoid valve 2, so that clean air or inert gas is filled in the terminal box 1. It is configured to be released.

In the present embodiment having the above-described configuration, as in the third and fourth embodiments,
The scavenging of explosive gas and the like and the pressure inside the terminal box 1 can be made higher than those outside. Further, the second solenoid valve 9
Is controlled by the power supply state monitoring device 4 provided in the terminal box 1, so that it is not necessary to externally control the opening and closing of the second solenoid valve 9. As described above, in the present embodiment, the terminal box 1 can be made lighter and simpler by providing two solenoid valves that open and close the terminals at the same time as the inside of the terminal box 1 is energized. Furthermore, there is no need to externally control the opening and closing of the second solenoid valve 9.

(6) Sixth Embodiment This embodiment is a modification of the second embodiment, and uses a three-way solenoid valve 11. That is, FIG. 7 is a diagram showing the configuration of the sixth embodiment of the terminal box according to the present invention, in which the gas supply pipe 3 arranged in the terminal box 1 from the gas supply device 7 is connected to the three-way solenoid valve 11. Through the branch pipe 3c, 3
It is branched to d. The distal end of the branch pipe 3c is open to the terminal box 1, and the branch pipe 3d is provided with a flow control valve 8.

Further, in the terminal box 1, an energization state monitoring device 4 is provided similarly to the first embodiment, and is configured to constantly monitor whether or not the inside of the terminal box 1 is energized. . When the inside of the terminal box 1 is not in an energized state by the energization state monitoring device 4, the branch pipe 3 c side is “open”, and the branch pipe 3 d side is “closed”. It is configured to release clean air or inert gas. On the other hand, when the terminal box 1 is energized, the branch pipe 3c immediately becomes “closed” and the branch pipe 3d becomes “open”, and a small amount of clean air or inert gas is supplied through the flow control valve 8. 1. The other configuration is the same as that of the first embodiment, and the description is omitted.

In the present embodiment having the above configuration, the terminal box 1 is not opened until the terminal box 1 is energized.
Through the side (branch pipe 3c side), scavenging with clean air or inert gas is performed. When the terminal box 1 is energized, the "open" side is automatically closed when not energized, and instead the "open" side (branch pipe 3d side) is opened when energized. Clean the terminal box 1 with a small amount of clean air or inert gas.
Release into. Thus, the pressure inside the terminal box 1 is made higher than that outside, so that even if the degree of sealing of the terminal box 1 is reduced, intrusion of flammable gas can be prevented.

As described above, in the present embodiment, by providing the three-way solenoid valve 11 and the flow regulating valve 8 that are opened and closed depending on whether or not the inside of the terminal box 1 is energized, the terminal box 1
Can be made lighter and simpler, and the three-way solenoid valve 1
Pressure fluctuations to the supply source of clean air and the like due to the opening and closing of 1 can also be reduced.

(7) Seventh Embodiment This embodiment is applicable to a case where an air device 20 such as a solenoid valve whose valve opening / closing operation is controlled by gas pressure or the like is provided in the terminal box 1. The supply gas to the air device 20 is used for scavenging the terminal box and the like. That is, as shown in FIG. 8, a gas supply pipe 21 provided for supplying gas from an external gas supply device 7 to an air device 20 such as a solenoid valve stored in advance in the terminal box 1 is connected to a terminal. It is branched in the box 1, and branch pipes 21a and 21b are formed.
An air device 20 is connected to one of the branched pipes 21a, and an electromagnetic valve 2 similar to that of the first embodiment is provided to the other branched pipe 21b.

In the terminal box 1, an energization state monitoring device 4 is provided similarly to the first embodiment, and is configured to constantly monitor whether or not the terminal box 1 is energized. . Then, when the inside of the terminal box 1 is not in a conducting state, the solenoid valve 2 is opened by the conducting state monitoring device 4 so that clean air or an inert gas is discharged into the terminal box 1. At the time of energization, the solenoid valve 2 is configured to be immediately closed. The other configuration is the same as that of the first embodiment, and the description is omitted.

In the present embodiment having the above-described configuration, air can be supplied to the solenoid valve 2 through the gas supply pipe 21 provided for the air device 20 originally housed in the terminal box 1. Scavenging inside the terminal box and pressure holding inside the terminal box 1 can be performed without laying external piping.

(8) Other Embodiments The present invention is not limited to the above-described embodiments, and the shapes and the number of the various constituent members can be appropriately changed. For example, depending on the size of the terminal box, the number of pipes for supplying clean air or inert gas into the terminal box may be increased, and the solenoid valve 2 may be installed in each of them. Also, measure the amount of clean air and inert gas supplied to the terminal box,
A configuration may also be adopted in which the terminal box cannot be energized until after the supply amount exceeds a predetermined amount.

[0040]

As described above, according to the present invention,
By providing a `` closed '' solenoid valve when energized that detects when power is first turned on in the terminal box, it releases clean air and inert gas into the terminal box when energized. Since the air can be scavenged, the weight of the terminal box can be reduced, and the electric equipment to be stored can be a non-explosion-proof equipment.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a terminal box according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a terminal box according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a terminal box according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a terminal box according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a terminal box according to a fifth embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a terminal box according to a fifth embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a terminal box according to a sixth embodiment of the present invention.

FIG. 8 is a diagram showing a configuration of a terminal box according to a seventh embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Terminal box 2 ... Electromagnetic valve 3 ... Gas supply piping 4 ... Electrification state monitoring device 5 ... Electrical equipment 6 ... Wiring 7 ... Gas supply device 8 ... Flow regulating valve 9 ... Second electromagnetic valve 10 ... External control power supply 11 ... three-way solenoid valve 20 ... air equipment 21 ... gas supply piping

Claims (6)

[Claims] 1. A terminal box in which a predetermined electric device is housed, and the electric device is wired and connected to the outside, and is used in an explosive atmosphere. And a gas supply pipe for supplying clean air or inert gas from the outside into the terminal box, and the gas supply pipe is provided with the power supply state monitoring means. A first solenoid valve controlled to open and close is attached,
A terminal box configured to close the first solenoid valve when the inside of the terminal box is energized. 2. The method according to claim 1, wherein the gas supply pipe is provided in a terminal box.
2. The terminal box according to claim 1, wherein the terminal box is branched, and the first solenoid valve is provided on one of the branches, and the flow control valve is provided on the other. 3. 3. The gas supply pipe according to claim 2, wherein
2. The branch according to claim 1, wherein the first electromagnetic valve is provided on one side, and a second electromagnetic valve controlled to be opened and closed from the outside of the terminal box is provided on the other side. Terminal box. 4. The terminal box according to claim 3, wherein a flow control valve is connected to the second solenoid valve in series. 5. The gas supply pipe according to claim 2, wherein
The first solenoid valve is disposed on one side, and the second solenoid valve is disposed on the other side, and both solenoid valves are configured to be opened and closed by the conduction state monitoring means. The terminal box according to claim 1, wherein: 6. A terminal box in which a predetermined electric device is housed, and the electric device is wired and connected to the outside, and is used in an explosive atmosphere. And a gas supply pipe for supplying clean air or inert gas from the outside into the terminal box, and the gas supply pipe is provided with the power supply state monitoring means. A three-way solenoid valve that is controlled to open and close is installed, one of which is opened and opened in the terminal box when the terminal box is in a non-energized state, and the other is provided with a flow regulating valve, A terminal box, wherein the terminal box is configured to be "open" when the inside is energized.