JPH0552537U - Safety equipment for combustion equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] Prevents overheating in a wide range of combustion equipment and ensures its operation. [Structure] A linear thermal fuse wire 1 is arranged in a meandering manner on a heat shield plate 20 on the outer back of the combustion chamber 13 and the heat exchanger 15. This thermal fuse wire 1 is obtained by coating the surface of a low-temperature molten metal wire 2 with a resin 3 having a melting point similar to that of the low-temperature molten metal wire 2.
By wrapping around, the molten metal wire 2 is surely melted, the conduction is cut off, and the combustion is stopped.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a safety device that detects abnormal overheating of combustion equipment and stops combustion before reaching a dangerous level.

[0002]

[Prior Art]

 Conventionally, in order to prevent abnormal overheating of combustion equipment, a glass tube-enclosed temperature fuse has been placed on the outer rear surface of the combustion chamber and heat exchanger, and the relay of the combustion control circuit is activated by fusing the temperature fuse due to abnormal overheating. There is a known safety device that causes the combustion to stop. However, in order to protect a wide area over the entire combustor, a large number of fuses must be arranged in a scattered manner, and the workability of wiring and mounting is poor. Therefore, there is a method in which a linear body made of solder, which is a low-temperature molten metal, is used as a contact member and stretched around the outside of the combustion chamber or heat exchanger to activate the relay even if it melts even at one place due to abnormal overheating. Has been figured out.

[0003]

[Problems to be solved by the device]

 However, when a linear body of low temperature molten metal is used, it may melt at an abnormally overheated location but may not be completely melted. That is, as shown in FIG. 6, even if the low temperature molten metal F is melted, the linear shape is maintained and the electrical continuity is maintained. It is considered that this is due to the surface tension of the low temperature molten metal F. It is also considered that this is due to a decrease in fluidity due to the inclusion of oxides on the surface of the low temperature molten metal F. Therefore, in reality, a reliable operation for detecting overheating cannot be expected so much. An object of the present invention is to solve the above problems, prevent overheating in a wide range in a combustion device, and ensure its operation.

[0004]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, a safety device for a combustion device according to the present invention comprises a series of linear bodies made of a low-temperature molten metal that is electrically conductive and melts at a preset temperature. In a safety device that is disposed outside of the wire and stops the combustion of the combustion equipment when the linear body is melted due to abnormal overheating, the linear body has a melting point similar to that of the low temperature molten metal. The point is that the insulating resin is covered.

[0005]

[Action]

 In the safety device for a combustion device of the present invention having the above-mentioned configuration, when damage such as cracks occurs in the combustion chamber or the heat exchanger, heat is released from the part and the inside of the device body case is abnormally overheated, which causes low temperature. The filament made of molten metal reaches the melting point and the overheated part begins to melt. On the other hand, the resin covering the linear body also begins to melt near this temperature. At this time, the melted linear body is wrapped with the melted resin, the tip is spherical, and is completely separated at the melted portion. As a result, the linear body is always disconnected in the overheated state, the conduction of the linear body is cut off, and abnormal overheating can be reliably detected. In this way, the combustion of the combustion equipment is stopped before it becomes dangerous.

[0006]

【Example】

 In order to further clarify the configuration and operation of the present invention described above, a preferred embodiment of the safety device for a combustion device of the present invention will be described below. FIG. 1 is a vertical cross-sectional side view of a gas water heater as an embodiment, and FIG. 2 is a view taken along the line XX of FIG. The gas water heater 10 is provided in the center of the main body case 11 and performs combustion of gas with a burner 12, and water and combustion exhaust gas that are connected to the upper part of the combustion chamber 13 and are passed through an endothermic pipe 14. A heat exchanger 15 for exchanging heat with the cold water, an exhaust duct 16 for discharging the combustion exhaust after the heat exchange, and an air supply fan 17 for supplying combustion air to the combustion chamber 13. And an air supply duct 18.

A heat shield plate 20 is provided between the rear plate 19 of the main body case 11, the combustion chamber 13, and the heat exchanger 15 with a predetermined gap from the rear plate 19. As shown in FIG. 2, one linear thermal fuse wire 1 is arranged in a meandering manner in the vertical direction on the heat shield plate 20, and is fixed by heat-resistant tapes 21 at the top and bottom. As shown in FIG. 3, the thermal fuse wire 1 is connected to a series of linear bodies 2 (hereinafter referred to as a molten metal wire 2) made of a low temperature molten metal which is conductive and melts at a preset temperature. It is a tube-shaped transparent resin 3 (insulator) having a melting point of approximately 3 is coated. In this embodiment, an alloy made of tin, lead, and cadmium (melting point 145 ° C.) is used for the molten metal wire 2, and a nylon elastomer (melting point 160 ° C.) is used for the resin 3.

Both ends of the temperature fuse wire 1 are connected to a combustion control circuit (not shown) via lead wires 22 and 23 shown in FIG. In the combustion control circuit, when the disconnection of the temperature fuse wire 1 (more accurately, the disconnection of the molten metal wire 2) is detected, that is, when the lead wires 22 and 23 are switched from the conductive state to the non-conductive state, the relay ( (Not shown) is activated to stop combustion. In this embodiment, an electromagnetic control valve (not shown) that controls the fuel supply to the burner 12 is closed.

Next, the operation of the thermal fuse wire 1 of this embodiment will be described. When damage such as cracks occurs in the combustion chamber 13 or the heat exchanger 15, heat is dissipated from that part and the inside of the main body case 11 is abnormally overheated. There is a nature. When such abnormal overheating occurs, the molten metal wire 2 near the damaged portion reaches the melting point and starts melting. On the other hand, the resin 3 covering the molten metal wire 2 also begins to melt near this temperature. In this embodiment, since the resin 3 is closer to the heat source than the molten metal wire 2, even if the melting point is slightly higher than that of the molten metal wire 2, the resin 3 melts at substantially the same time. It does not matter which one melts first. At this time, the melted molten metal wire 2 is wrapped in the melted resin 3 as shown in FIG. 4, and the tip is spheroidized and completely separated. As a result, the conduction of the molten metal wire 2 is cut off, the relay is activated, and the electromagnetic control valve is closed so that the gas supply is stopped. Therefore, the combustion is stopped before it becomes dangerous.

As described above, according to this embodiment, abnormal overheat can be detected over a wide range, and its operation is reliable, resulting in extremely high reliability. Further, the mounting of the temperature fuse wire 1 is very simple, and the number of steps and the number of parts are reduced as compared with the conventional one in which a plurality of temperature fuses are scattered, and the cost can be reduced. Further, since the resin 3 covering the molten metal wire 2 is insulative, it is not necessary to provide any insulation protection such as an insulating sheet or a spacer.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention. .. For example, as shown in FIG. 5 (A), the molten metal wire 2 may be sandwiched between two resin plates 4 and 5 (having the same melting point as the molten metal wire 1). .. Further, as shown in FIG. 2B, the resin 6 knitted in a mesh shape may be coated on the surface of the molten metal wire 2 to facilitate the attachment. According to this, the molten metal wire 2 can be easily inserted by shrinking both ends of the resin 6 in the direction of the arrow a to widen the opening diameter, and then pulling in the direction of the arrow b, the resin 6 is adhered to the molten metal wire 2 closely. It can be attached. Further, in the present embodiment, the thermal fuse wire 1 is provided on the back surface of the combustion chamber 13 and the heat exchanger 15, but it may be provided on the side surface or the front surface to further enhance safety. The temperature difference between the melting point of the molten metal wire and the melting point of the resin is preferably within ± 30%.

[0012]

[Effect of the device]

 As described above in detail, in the safety device for the combustor of the present invention, the linear body made of the low-temperature molten metal is arranged outside the combustion chamber and the heat exchanger, and the melting point of the linear body is similar to that of the linear body. Since it covers the resin that has heat, it is possible to detect abnormal overheating over a wide range, and it is possible to reliably melt the linear body by melting the resin, which is extremely reliable. ..

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a gas water heater as one embodiment.

FIG. 2 is a view taken along line XX of FIG.

FIG. 3 is a schematic perspective view of a thermal fuse wire.

FIG. 4 is an explanatory diagram showing a blown state of a temperature fuse wire.

FIG. 5 is an explanatory diagram showing another embodiment.

FIG. 6 is an explanatory diagram showing a conventional molten state.

[Explanation of symbols]

1 ... Thermal fuse wire, 2 ... Molten metal wire, 3 ... Resin, 13
… Combustion chamber, 15… Heat exchanger

Claims (1)

[Scope of utility model registration request] 1. A series of linear bodies made of a low temperature molten metal which is electrically conductive and melts at a preset temperature is arranged outside a combustion chamber of a combustion device and a heat exchanger, and the linear body is provided. In the safety device that stops the combustion of the combustion equipment when it melts due to abnormal overheating, the linear body is covered with an insulating resin having a melting point similar to that of the low temperature molten metal. A characteristic safety device for combustion equipment.