JP2001355831A - Device equipped with internal pressure explosion preventing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device equipped with an internal pressure explosion preventing structure reduced in the cost of the same. SOLUTION: The device is equipped with the internal pressure explosion preventing structure including an internal pressure vessel 3 accommodating electric instruments 13, 15, 16, a pressure detecting means 26 for detecting a differential pressure between the inside and the outside of the vessel 3, a gas supplying means 7 for supplying protective gas into the vessel 3 and a control means 17 for controlling the electric instruments 13, 15, 16. The pressure detecting means 26 is provided in the vessel 3 and the control means 17 energizes the pressure detecting means 26 after sending a predetermined protective gas into the vessel 3 through the gas supplying means 7 while the electric instruments are energized when the differential pressure between the inside and the outside of the vessel 3, which is detected by the energizing of the pressure detecting means 26, is higher than a predetermined value. According to such a constitution, the pressure detecting means 26 is positioned in the vessel 3 and is energized after the protective gas of a predetermined amount is sent into the vessel 3 whereby the employment of instruments such as a barrier relay or the like is not required and the cost of the device can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus having an internal pressure explosion-proof structure.

[0002]

2. Description of the Related Art A conventional apparatus provided with an internal pressure explosion-proof structure includes an internal pressure vessel containing electric equipment, a gas supply means for supplying a protective gas to the internal pressure vessel, and an inside and outside of the internal pressure vessel installed outside the internal pressure vessel. And a control unit electrically connected to an electric device, a blower, a pressure detection unit, and the like. In a device equipped with a conventional internal pressure explosion-proof structure, for safety, a sufficient amount of protective gas is injected into the internal pressure container while the pressure detecting means is energized, and the differential pressure between the inside and the outside of the internal pressure container is determined. When the value is equal to or larger than the value, the electric device in the internal pressure vessel is energized.

[0003]

In a conventional apparatus having an internal pressure explosion-proof structure, the pressure detecting means is provided outside the internal pressure vessel, so that the pressure detecting means and the control unit are electrically connected. In this case, it is necessary to support an intrinsically safe explosion-proof structure so that the gas around the device is not ignited by energizing the pressure detecting means. Therefore, in a device having a conventional internal pressure explosion-proof structure, the pressure detecting means is connected to the control means via devices such as an intrinsically safe explosion-proof relay, that is, a barrier relay. As described above, in a device having a conventional internal pressure explosion-proof structure, equipment such as a barrier relay for complying with the intrinsically safe explosion-proof structure is required, resulting in an increase in device cost.

[0004] As a configuration corresponding to electric explosion-proof without using devices such as barrier relays, it is conceivable to use pressure detecting means having a pressure-resistant explosion-proof structure as pressure detecting means. However, such a pressure detecting means is expensive, and still increases the cost of the apparatus.

An object of the present invention is to reduce the cost of an apparatus having an internal pressure explosion-proof structure.

[0006]

According to the present invention, there is provided an apparatus having an internal pressure explosion-proof structure, comprising: an internal pressure vessel containing electric equipment; pressure detecting means for detecting a pressure difference between the inside and outside of the internal pressure vessel; Gas supply means for supplying a protective gas to the internal pressure container,
Control means for controlling the electrical equipment, wherein the pressure detection means is provided in the internal pressure vessel, the control means energizes the pressure detection means after the gas supply means sends a predetermined amount of protective gas into the internal pressure vessel The above-mentioned problem is solved by energizing the electric device when the pressure difference between the inside and the outside of the internal pressure container detected by energizing the pressure detecting means is equal to or more than a predetermined value.

With such a configuration, the pressure detecting means is located in the internal pressure vessel and is energized after a predetermined amount of protective gas is sent into the internal pressure vessel. It is possible to prevent ignition of gas etc. Further, the electric equipment in the internal pressure vessel is energized when the differential pressure between the inside and the outside of the internal pressure vessel detected by the pressure detecting means is equal to or higher than a predetermined value. Therefore, when electrically connecting the pressure detecting means and the control means, it is possible to configure a device corresponding to the internal pressure explosion-proof structure without having to perform connection via devices such as a barrier relay. The cost of the device can be reduced.

Further, there is provided an apparatus having the above-mentioned internal pressure explosion-proof structure, wherein the internal pressure container comprises: an electric equipment room containing electric equipment; a combustion chamber for burning with a protective gas and fuel from the electric equipment room; An exhaust passage communicating with the combustion chamber and exhausting the gas in the combustion chamber, and the gas supply means corresponds to an internal pressure explosion-proof structure if the combustion apparatus is configured to supply the protective gas into the electrical equipment chamber. This is preferable because the cost of the combustion device can be reduced. In addition, it is preferable to use a liquefied gas evaporator including the above-described combustion device because the cost of the liquefied gas evaporator can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a combustion apparatus according to the present invention will be described below with reference to FIGS. FIG. 1 is a diagram showing a schematic configuration of a combustion device which is a device having an internal pressure explosion-proof structure to which the present invention is applied, and a liquefied gas evaporator provided with the combustion device. FIG. 2 is a diagram showing a time chart of the operation of each part during the operation of the liquefied gas evaporator. The apparatus having the internal pressure explosion-proof structure of the present embodiment is a combustion apparatus having a ventilation internal pressure explosion-proof structure, and a case where the combustion apparatus of the present embodiment is used as a combustion unit of a liquefied gas evaporator will be described as an example. .

As shown in FIG. 1, the combustion apparatus 1 of this embodiment is a gas supply means for supplying a protective gas to the electric equipment chambers 3 and the combustion chambers 5, the electric equipment chambers 3 and the combustion chamber 5, which are internal pressure vessels. , An exhaust pipe 9, a fuel supply pipe 11 for supplying fuel, a gas valve 13 and an adjustment valve 14 including an electromagnetic valve provided in the fuel supply pipe 11, an ignition 15 for igniting the fuel, and a frame rod 16. And a control unit 17 for controlling combustion. The electrical equipment room 3 and the combustion chamber 5 communicate with each other via an air room 19. The electrical equipment room 3 and the air chamber 19 communicate with each other through an opening 23 formed in a part of a partition 21 that separates the electrical equipment room 3 and the air chamber 19. A fuel supply pipe 11 is inserted into the electrical equipment room 3 and the air chamber 19.
The end 25 on the side from which the fuel is ejected is open in the combustion chamber 5.

A pressure switch, which is a pressure detecting means, is activated in the electric equipment room 3 and outputs a signal when the pressure difference between the inside and the outside of the electric equipment room 3 becomes higher than a predetermined pressure difference. 26, a gas valve 13 and the like are provided. The air chamber 19 and the combustion chamber 5 communicate with each other through a communication portion 29 formed around the end 25 of the fuel supply pipe 11 in the partition wall 27 that separates the air chamber 19 and the combustion chamber 5. The control unit 17 is installed in an electrical component box 30 which is a box having a flameproof structure.

The blower 7 is an explosion-proof blower. The blower tube 31 of the blower 7 is located on the opposite side to the air chamber 19 of the electrical equipment room 3, that is, on the upstream side with respect to the flow of the protective gas in the electrical equipment room 3. Is in communication with An intake port 33 of the blower 7 communicates with an intake pipe 35. The exhaust pipe 9 communicates with the portion of the combustion chamber 5 opposite to the air chamber 19, that is, downstream of the flow of the protective gas in the combustion chamber 5. The intake port 37 of the intake pipe 35 and the exhaust port 39 of the exhaust pipe 9 open to the non-dangerous area 41, respectively. Therefore, in this embodiment, clean air is used as the protective gas, and
This air is also used as combustion air.

The combustion chamber 5 of the combustion apparatus 1 according to the present embodiment is disposed in a hot water tank 43 in which a heat medium 42 is accommodated, and a liquefied gas flows through the hot water tank 43. A heat exchanger 45 composed of a heat pipe is installed. The liquefied gas evaporator of the present embodiment heats a liquid liquefied gas flowing through the heat exchanger 45, such as liquefied petroleum gas (LPG) or liquefied natural gas (LNG), by the combustion device 1. The LPG and LNG in the gas phase are obtained by being evaporated by the heat of the medium 47. Further, the combustion device 1 uses LPG as fuel.
Or LNG. Therefore, the combustion apparatus 1 constituting the liquefied gas evaporator, that is, the electric equipment room 3, the combustion chamber 5, the blower 7, the electric equipment box 30, and the like are in the danger area 48, and the electric equipment box 30, the blower 7, and the electric equipment room. The wiring 49 for electrically connecting the gas valve 13, the ignition 15, the frame rod 16 and the like in the internal pressure vessel such as 3 is an explosion-proof wiring. Also,
The wiring 49 is a wiring 4 in an internal pressure vessel such as the electric equipment room 3.
It is electrically connected to the gas valve 13, the ignition 15, the frame rod 16, and the like via a wiring 51, which is a normal wiring electrically connected to 9.

The operation of the combustion apparatus 1 having such a configuration and the features of the present invention will be described. That is, as shown in FIG. 2, in the combustion device 1 having the ventilation type internal pressure explosion-proof structure, when the operation is started, the combustion device 1 is provided in the control unit 17 or electrically connected to the control unit 17. When the power switch and the operation command switch that are not turned on are turned on and the start / stop input is turned on by the operation start command, the control unit 17
Turns on the blower 7 and starts blowing the clean air to the electric equipment room 3. The controller 17 scavenges the inside of the internal pressure vessel with a sufficient scavenging amount, for example, 5 times or more of the clean air volume of the internal pressure vessel. At this time, the controller 17 manages the scavenging amount based on the scavenging time T. For example, the scavenging time T required to perform scavenging at least five times the volume of the internal pressure vessel is determined by the flow rate of the blower 7 and the volume of the internal pressure vessel, that is, the blower tube 31 of the blower 7, the electrical equipment room 3, and the air chamber 19. , The combustion chamber 5, and the volume of the exhaust pipe 9, and the scavenging time T is managed by setting or storing the calculated scavenging time T in the control unit 17. For the flow rate of the blower 7, for example, the relationship between the flow rate and the pressure in the internal pressure vessel is obtained in advance, and based on the relationship between the flow rate and the pressure in the internal pressure vessel, the internal pressure vessel such as the electric equipment room 3 or the air chamber 19 is used. The internal pressure is set so as to be kept higher than a predetermined pressure, for example, 49 Pa or more with respect to the outside of the internal pressure vessel.

Subsequently, when a predetermined scavenging time T has elapsed, the control unit 17 energizes the pressure switch 26 and checks the output of the pressure switch 26. At this time, if the pressure difference between the inside and outside of the electric equipment room 3 is equal to or higher than the value set in the pressure switch 26 in advance, the pressure switch 26 is turned on and a signal is output to the control unit 17. Pressure switch 2
When a signal is input to the control unit 17 from the control unit 6, the differential pressure between the inside and the outside of the internal pressure container such as the electric device room 3 and the air chamber 19 is fixed inside the electric device room 3 by the clean air. It will be kept above the value.

In a state where the signal from the pressure switch 26 is input, the control unit 17 controls the electric device having a portion where an electric spark may be generated in the electric device room 3 or the air room 19. Power is supplied to the gas valves 13, the ignition 15, the frame rod 16, and the like, which are devices. That is, while the signal from the pressure switch 26 is being input, the control unit 17 energizes the gas valve 13 to turn the gas valve 13 on, that is, to open the gas valve 13 and flow the fuel gas toward the end 25 of the fuel supply pipe 11. Then, the ignition 15 is energized for a predetermined time to ignite the fuel gas, and the flame rod 16 is energized to be turned on to detect the presence or absence of a flame. Further, when stopping combustion, the control unit 17 controls the pressure switch 26.
In the state where the signal is input, the power supply to the gas valve 13 and the frame rod 16 is cut off to stop the combustion by turning off the power, and then the power supply to the blower 7 and the pressure switch 26 is cut off to turn off the power. I do. When the combustion is started again, each electric device is energized while the signal from the pressure switch 26 is being input to the control unit 17 by the same operation as described above. In a condition where clean air such as inside 19 is difficult to be replaced with flammable gas or the like, the second scavenging time t from turning on the blower 7 to turning on the pressure switch 26 is the case where the operation is started first. Can be shorter than the scavenging time T.

As described above, in the combustion apparatus 1 having the internal pressure explosion-proof structure of the present embodiment, the pressure switch 26 as the pressure detecting means is located in the electric equipment room 3 as the internal pressure vessel. Electric equipment room 3 or air room 1 by blower 7
When a predetermined amount of protective gas, that is, clean air from the non-hazardous area 41 is started to be sent into the inside of the fuel cell 9 or the like, power is supplied when a scavenging time T has elapsed. Therefore, it is possible to prevent ignition of gas or the like when the pressure switch 26 is energized. Further, an electric device having a portion where an electric spark or the like is generated in the electric device room 3 or the air room 19, that is, the gas valve 13, the ignition 1
5. The frame rod 16 and the like are in a state where there is an input from the pressure switch 26 to the control unit 17, that is, the differential pressure between the inside and the outside of the inner pressure container such as the electric equipment room 3 and the air room 19 is higher than a predetermined value. It is energized when it is present. Therefore, a device corresponding to the internal pressure explosion-proof structure can be configured without the necessity of interposing devices such as a barrier relay to electrically connect the pressure switch 26 and the control unit 17, so that the cost of the device can be reduced. .

Further, when a commercially available barrier relay is used, since the terminal shape on the side of the barrier relay is single, it is necessary to perform wiring work so as to prevent erroneous wiring, and the wiring work cannot be performed efficiently. However, in the present embodiment, since a barrier relay becomes unnecessary, various shaped terminals can be used for wiring, and erroneous wiring can be easily prevented, so that wiring work can be performed efficiently. In addition, since there is no wiring via the barrier relay, the number of wirings is reduced and the number of assembling steps can be reduced. Also, when it is desired to use devices such as a barrier relay, and when the control unit and the devices such as the barrier relay are housed in one electrical box, the electrical box becomes large. Therefore, only the control unit 17 needs to be housed in the electrical box 30, and the electrical box can be downsized.

Further, in this embodiment, the pressure switch 2
6 is in the electrical equipment room 3, the pressure switch 26
Since it is not affected by dust or dust outside the combustion device 1, that is, in the atmosphere of the hazardous place 48, the life of the pressure detection means is extended, and the reliability of the combustion device 1 having an internal pressure explosion-proof structure is improved. can do. In addition, in the assembly, maintenance and inspection work of the combustion device 1 which is a device having an internal pressure explosion-proof structure and the liquefied gas evaporator provided with the combustion device 1, tools, the combustion device 1 and the liquefied gas evaporator are used as pressure switches. By not receiving an impact due to the collision of the component parts or the like, the life of the pressure detecting means can be extended, and the reliability of the combustion apparatus 1, which is an apparatus having an internal pressure explosion-proof structure, can be improved.

In the liquefied gas evaporator, the heat medium 4
2, there may be provided a temperature sensor for detecting the temperature or the like, a liquid level sensor for detecting the liquid level position of the heat medium, and the like. If these sensors do not correspond to the explosion-proof structure, it is necessary to connect each sensor and the like via devices such as a barrier relay when electrically connecting to the control unit 17. However, since devices such as barrier relays for connecting the pressure sensor 26 to the control unit 17 are not required, the number of devices such as barrier relays can be reduced, and the cost of the device can be reduced. If sensors such as a temperature sensor and a liquid level sensor are configured to support a pressure-resistant explosion-proof structure, devices such as a barrier relay can be eliminated from the liquefied gas evaporator, further reducing the cost of the device. be able to.

In this embodiment, the gas valve 13 is energized and turned on, and the combustion gas is ignited directly by the ignition 15 when the gas valve 13 is open. However, a proportional valve is provided in the fuel gas flow path. Such a configuration can be adopted. In addition, the fuel gas main combustion channel and pilot combustion channel,
A switching valve between the main combustion flow path and the pilot combustion flow path is provided, and pilot combustion is always performed in a standby state, and when transition to the combustion state is performed, there is an input from the pressure switch 26 to the control unit 17, The switching valve in the internal pressure vessel such as the electrical equipment room 3 may be energized to switch from pilot combustion to main combustion.

In the present embodiment, the control unit 17 is housed in the electrical box 30 formed of a single housing provided in a danger area.
Not limited to this, the control means can also be provided in the non-dangerous area 41, and the control means has a plurality of housings, for example, a plurality of housings individually housing circuits and devices corresponding to each function. It can also be configured.

Further, in the present embodiment, the combustion apparatus 1 used as a combustion section of a liquefied gas evaporator as an apparatus having an internal pressure explosion-proof structure has been described as an example. However, the present invention is not limited to this, and for example, a boiler The present invention can be applied to various types of combustion devices provided in various apparatuses and devices having a combustion unit having an internal pressure explosion-proof structure such as a heater and a dryer. Further, the present invention can be applied to not only a combustion device but also devices having various internal pressure explosion-proof structures. In addition, the present embodiment is an apparatus having a ventilation type internal pressure explosion-proof structure, but the present invention is also applicable to an apparatus having a sealed type internal pressure explosion-proof structure.

[0024]

According to the present invention, the cost of an apparatus having an internal pressure explosion-proof structure can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an embodiment of a combustion apparatus having an internal pressure explosion-proof structure to which the present invention is applied, and a liquefied gas evaporating apparatus having the combustion apparatus.

FIG. 2 is a diagram showing a time chart of the operation of each part during operation of the liquefied gas evaporator.

[Description of Signs] 1 Combustion device 3 Electrical equipment room 5 Combustion chamber 7 Blower 13 Solenoid valve 15 Ignition 16 Flame rod 17 Control unit 26 Pressure switch

Continued on the front page (72) Inventor Shosuke Yagi 23 Minami-Kashima, Futamata-cho, Tenryu-shi, Shizuoka Prefecture F-term in Yazaki Keiki Co., Ltd. 3K023 HA14 HA20 3K068 AA02 AA03 BB02 BB12 BB24 CB16 DA06

Claims (3)

[Claims] An internal pressure vessel containing an electric device; a pressure detecting means for detecting a pressure difference between the inside and the outside of the internal pressure vessel; a gas supply means for supplying a protective gas to the internal pressure vessel; An internal pressure explosion-proof structure including control means for controlling equipment, wherein the pressure detection means is provided in the internal pressure vessel, and the control means is such that the gas supply means supplies a predetermined amount of protective gas to the internal pressure vessel. After being sent into the pressure detecting means, the pressure detecting means is energized, and when the pressure difference between the inside and outside of the internal pressure container detected by energizing the pressure detecting means is equal to or more than a predetermined value, the electric equipment is energized. An apparatus characterized in that: 2. An apparatus provided with an internal pressure explosion-proof structure according to claim 1, wherein said internal pressure vessel is burned by an electric equipment room containing electric equipment, and said protective gas and fuel from said electric equipment room. A combustion chamber which communicates with the combustion chamber and exhausts a gas in the combustion chamber to exhaust the gas in the combustion chamber, and wherein the gas supply means supplies the protective gas into the electrical equipment chamber. . 3. A liquefied gas evaporator comprising the combustion device according to claim 2.