JPH0740837Y2 - Overheat prevention device for combustion equipment - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention is applied to the case where a crack or the like occurs in a combustion chamber of gas combustion equipment, oil combustion equipment, a heat exchanger, or the like due to abnormal overheating that may cause a fire. In addition, the present invention relates to an overheat prevention device for a combustion device that immediately stops the supply of fuel for safety.

[Conventional technology]

As a conventional overheat prevention device for a combustion equipment of a water heater, for example, as shown in FIG. 4, one glass tube or a glass tube is provided at the rear of the outer surface of the combustion chamber 1'or the heat exchanger 2'of the combustion equipment. Generally, a ceramic tube-enclosed type thermal fuse 3'is attached and the connection terminal of the thermal fuse 3'is connected to a combustion control circuit or the like. However, a plurality of thermal fuses are connected to the combustion chamber and the heat exchanger. There are also proposals that are scatteredly provided on the outside.

[Problems to be solved by the device]

For combustion equipment such as commercial water heaters that are frequently used, the combustion chamber or heat exchanger may overheat abnormally during continuous use for a long time, causing cracks, perforations, etc. The hot exhaust gas may leak from the cracks or holes to burn the outer shell and cause a fire. However, one thermal fuse in the above-mentioned prior art is used as a combustion chamber or a rear portion of the outer surface of the heat exchanger. The one attached only to has a problem that the thermal fuse does not work if the cracks or holes in the combustion chamber or heat exchanger due to abnormal overheating are far from the thermal fuse. In the case where the fuses are scatteredly arranged on the outer surface of the combustion chamber and heat exchanger, even if many temperature fuses are mounted on the outer surface of the combustion chamber and heat exchanger, cracks, holes, etc. due to abnormal overheating may occur. Be local Therefore, the thermal fuse does not always detect this and operate reliably, and it is only a complement to the above-mentioned drawbacks even if one thermal fuse is attached, and it does not cause cracks or holes in unspecified places. It is impossible to deal with it, and moreover, it is necessary to attach a plurality of temperature fuses to the combustion chamber and a plurality of outer surfaces of the heat exchanger, so that the work such as wiring and assembling requires a great deal of time and skill, and the workability is extremely poor. However, there is a problem that the cost becomes high.

The present invention has been made in view of such problems of the conventional technology,
It is an object of the present invention to provide a device for preventing overheating of a combustion device that operates quickly and reliably regardless of the location of cracks, holes, etc. due to abnormal overheating in the combustion chamber, heat exchanger, etc.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the invention of claim 1 in the device for preventing overheating of a combustion device according to the present invention provides the entire range of at least one of the combustion chamber of the combustion device and the rear and side surfaces of the outer surface of the heat exchanger. A closed duct having an inner side wall 3a and an outer side wall 3b for guiding the hot air is provided, and an opening for concentrating and discharging the hot air in the duct is provided at the upper part of the duct, which is preset in the vicinity of the opening. A temperature sensor that operates at a different temperature is installed, and the temperature sensor is incorporated in a combustion control circuit or the like. Further, the invention of claim 2 is such that the duct has a combustion chamber and a heat exchanger. The outer surface of the duct is provided at the rear portion and both sides of the duct, and the inner wall of the duct 3 is provided.
3a is formed of a plate-shaped member having lower heat resistance than the outer wall 3b.

[Action]

In the invention according to claim 1 in the overheat prevention device for the combustion equipment of the present invention having the above-mentioned structure, even if cracks, perforations or the like due to abnormal overheating occur in any of the combustion chamber, the heat exchanger and the like. The hot air flows toward the upper opening in the duct composed of the inner wall and the outer wall provided in the entire range of at least one of the rear and side of the outer surface, and concentrates near the opening. The provided temperature sensor immediately detects this and operates, and the combustion control circuit operates to stop the supply of fuel. Further, according to the invention of claim 2, even if cracks, perforations or the like due to abnormal overheating occur at any of the rear part and both side parts of the combustion chamber and heat exchanger, the hot air is generated on the outer surface of the rear part and both side parts. Since the flow in the duct provided in the entire range is directed toward the upper opening and concentrated near the opening, the temperature sensor provided near the opening immediately senses this and operates, and the combustion control circuit operates to operate the fuel Stop the supply. In the inventions according to claims 1 and 2, the duct functions as a heat insulating layer during normal operation.

Further, in the device according to the third aspect, since the inner wall of the duct is formed of a plate-shaped member having lower heat resistance than the outer wall, the duct leaks from cracks and perforated portions of the combustion chamber and the heat exchanger. Even if the duct burns due to high-temperature exhaust gas, the inner wall of the duct with low heat resistance will burn and flow into the duct, so be sure to use a temperature sensor until the outer wall of the duct burns. Can be detected. Of course, if both the inner wall member and the outer wall member are made of members having high heat resistance, the same effect can be obtained, but the cost becomes high.

〔Example〕

An embodiment of an overheat prevention device in a combustion device according to the present invention will be described below with reference to the drawings.

The embodiment is an example in which the overheat prevention device of the present invention is applied to a wall-mounted forced air supply type gas water heater.

Embodiment 1 In FIGS. 1 and 2, reference numeral 1 denotes a combustion chamber of a gas water heater, a heat exchanger 2 is integrally provided on an upper portion of the combustion chamber 1, and a water supply pipe 6 is spirally provided on an outer surface thereof. Wind up and heat exchanger 2
Is connected to the inlet side of the heat absorption tube 7. Further, a gas burner 8 is installed in the lower part of the combustion chamber 1, and the heat exchanger 2 is heated by the gas burner 8 to heat and raise the temperature of the cold water flowing through the heat absorbing pipe 7 of the heat exchanger 2 to heat the heat absorbing pipe 7. Hot water is supplied from the hot water supply pipe 9 connected to the outlet side of the kitchen to the sink or the bathtub of the kitchen. Reference numeral 10 denotes an air supply chamber that is hermetically connected to the lower portion of the combustion chamber 1, and the outlet of the air supply fan F is provided on the bottom wall of the air supply chamber 10.
11 is connected and opened, and the bottom wall of the air supply chamber 10 and the gas burner 8 are connected.
A perforated straightening plate 12 is provided between the air supply fan F and the air outlet 11 and the air supplied to the bottom of the air supply chamber 10 is rectified by the perforated straightening plate 12 and used as combustion air for the gas burner 8. The combustion chamber 1 is forcedly supplied with air.

Reference numeral 3 denotes a sealed duct which comprises an inner side wall 3a and an outer side wall 3b for guiding hot air. The duct 3 surrounds the combustion chamber 1, the heat exchanger 2, and the outer surface of the air supply chamber 10 at the rear and both sides. A single opening 4 is provided at the center of the upper rear surface of the duct 3 for radiating the hot air in the duct 3 so that the hot air in the duct 3 is concentrated and radiated to the opening 4. The inner wall 3a of the duct 3 is formed of a plate-shaped member having lower heat resistance than the outer wall 3b. For example, the inner wall 3a is formed of a galvanized steel plate having low heat resistance, and the outer wall 3b is formed of a stainless plate having high heat resistance. In the embodiment, the ducts 3 are provided on the rear and both sides of the outer surface of the combustion chamber 1, the heat exchanger 2 and the air supply chamber 10. Also, although only one opening 4 is made at the center of the upper rear surface of the duct 3, the duct 3
It is also free to drill two or three openings close to each other in the center of the upper rear surface. The plate-shaped members forming the inner wall 3a and the outer wall 3b of the duct 3 having different heat resistance are not limited to the galvanized steel plate and the stainless steel plate of the embodiment.

A temperature sensor 5 is installed near the opening 4 and is turned off at a preset temperature. For example, a temperature fuse of a glass tube or ceramic tube sealed type (fuse fusing type) is used. Is connected to a combustion control circuit or the like of a gas water heater, and when the temperature sensor 5 senses abnormal heating and is turned off, the fuel control valve is closed and gas supply is stopped. The set temperature of the temperature sensor 5 is, for example, 120 ° C to 2 ° C.
Use a safe temperature of around 00 ℃.

In the figure, 13 is an exhaust tube, 14 is an outer case, and 15 is an air intake port provided in the outer case 14.

In the above configuration, if there is a risk of fire due to cracks, perforations, etc. due to abnormal overheating at any of the combustion chamber 1, the heat exchanger 2, and the rear portion of the outer surface of the air supply chamber 10 and both sides, there is a risk of fire. Since the inside of the duct 3 surrounding these outer surfaces is concentrated toward the opening 4 in the upper center, the temperature sensor 5 provided in the vicinity of the opening 4 immediately detects this and turns off. It operates to shut off the power supply to the combustion control circuit, close the fuel control valve, and immediately stop the gas supply for safety.

The duct 3 effectively functions as a heat insulating layer during normal operation without abnormal overheating.

Embodiment 2 In FIG. 3, a duct 3 is provided only in the rear portion of the outer surface of the combustion chamber 1 and the heat exchanger 2 so that cracks, perforations, etc. due to abnormal overheating may occur in either the rear portion of the combustion chamber 1 or the heat exchanger 2. When there is a risk of fire occurring at a location, the hot air flows in the duct 3 toward the opening 4 in the upper center and concentrates in the vicinity of the opening 4, so that the temperature sensor 5 provided in the vicinity of the opening 4 Immediately sensing and activating, the power supply to the combustion control circuit is cut off, the fuel control valve is closed to immediately stop the gas supply for safety, and other configurations and operations are the same as those in the first embodiment. The same reference numerals are given to the parts and the description thereof will be omitted.

[Effect of device]

In the device for preventing overheating of a combustion device according to the present invention, the cracks, perforations, etc. due to abnormal overheating are in the entire range of at least one of the rear and side surfaces of the combustion chamber and the outer surface of the heat exchanger. Even if it occurs at the location of the duct, the hot air is concentrated at the opening of the duct, and the temperature sensor provided near the opening immediately senses this and operates to shut off the energization of the combustion control circuit and close the fuel control valve. If any cracks or punctures due to abnormal overheating that may cause a fire occur in the combustion chamber and heat exchanger, etc., the overheating prevention means will operate promptly and reliably to prevent the fire. In order to prevent the occurrence of such a phenomenon, it is particularly effective when applied to a frequently used gas water heater such as a commercial gas water heater.
In addition, work such as wiring and assembling is extremely simple, so that workability is improved and cost is reduced.

According to the second aspect of the present invention, even if cracks, perforations, etc. due to abnormal overheating occur in any of the rear portion and both side portions (unspecified local position) of the combustion chamber, the heat exchanger, etc., the hot air is generated in the duct. The temperature sensor is concentrated in the opening, and the temperature sensor provided near the opening immediately senses this and operates, cutting off the power supply to the combustion control circuit and closing the fuel control valve to immediately stop the gas supply. This is effective when applied not only to the gas water heater but also to the case where both sides of the combustion device are close to a wall or the like.

In the inventions of claims 1 and 2, it is not necessary to provide another heat insulating material on the inner surface of the outer case because the duct functions as a heat insulating layer to maintain safety during normal operation without abnormal overheating.

According to the third aspect of the invention, since the inner wall of the duct is formed of a plate-shaped member having lower heat resistance than the outer wall, the duct of high temperature exhaust gas leaking from cracks and perforated parts of the combustion chamber and the heat exchanger, etc. Even if a burnout occurs, the inner wall of the duct will be burnt first and flow into the duct, and the outer wall of the duct can be reliably detected by the temperature sensor until it burns out. Of course, the same effect can be obtained if both the inner wall member and the outer wall member are made of members having high heat resistance.

[Brief description of drawings]

The drawings show an embodiment of an overheat prevention device for a combustion device according to the present invention. FIG. 1 is a vertical sectional side view of the embodiment 1, FIG. 2 is a cross-sectional plan view taken along line XX of FIG. FIG. 3 is a transverse plan view of the second embodiment, and FIG. 4 is a vertical side view of the conventional example. 1 ... Combustion chamber, 2 ... Heat exchanger, 3 ... Duct, 3a ... Inner wall,
3b ... outer wall, 4 ... opening, 5 ... temperature sensor.

Claims (3)

[Scope of utility model registration request] 1. A combustion chamber (1) and a heat exchanger (2) of a combustion device.
A closed duct (3) consisting of an inner side wall (3a) and an outer side wall (3b) for guiding hot air is provided in the entire area of at least one of the rear and side surfaces of the outer surface of the duct (3). Opening (4) that concentrates and releases hot air in the duct (3) at the top
Combustion characterized in that a temperature sensor (5) that operates at a preset temperature is installed near the opening (4), and the temperature sensor (5) is incorporated in a combustion control circuit. Equipment overheat prevention device. 2. The duct (3) is provided in the combustion chamber (1) and the heat exchanger (2) over the entire area of the rear and both sides of the outer surface.
Overheat prevention device for the gas water heater described. 3. The inner wall (3a) of the duct (3) is connected to the outer wall (3).
b) The overheat prevention device for a combustion device according to claim 1 or 2, which is formed of a plate-shaped member having lower heat resistance.