JPH033800Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The invention is a safety device for forced combustion instantaneous water heaters,
In particular, the present invention relates to a safety device suitable for a thin forced combustion instantaneous water heater installed close to a wall surface.

[Conventional technology]

As a safety device for instantaneous water heaters, the body of the heat exchanger is equipped with a temperature detection means such as a bimetal switch or temperature fuse, which detects a temperature rise on the heat exchanger wall due to abnormal combustion such as dry heating. A device configured to notify this and close a solenoid valve is generally used.

However, with these conventional safety devices, thermal fatigue and corrosion caused by repeated heating and cooling of the heat exchanger can cause holes or cracks in the heat exchanger, resulting in combustion gas leaks. However, the problem is that it cannot be detected.

In order to improve this problem, as shown in FIG.
A through hole 3 communicating with the outside air is bored in one place of the cover 2, and an abnormal temperature detecting means 4 which is activated by detecting abnormal temperature due to combustion gas leakage is arranged in the through hole 3, Accordingly, a safety device for instantaneous water heaters has been proposed that prevents the occurrence of secondary disasters due to combustion gas leakage from heat exchangers. (Refer to Utility Model Publication No. 60-38830) [Problems to be solved by the invention] In the prior art of this invention, as shown in FIG. Since it is necessary to surround the entire circumference with the cover 2 to maintain a large volume of space A', if holes or cracks occur in the body plate part 1a due to thermal fatigue, corrosion, etc., combustion will occur in the space A'. The temperature detection means 4 detects an abnormal temperature when the gas is discharged to the outside air from the through hole 3 after being filled with gas, and closes the solenoid valve to cut off the fuel supply, so it only takes time to detect the abnormal temperature. Moreover, there is a problem in that the operation of the temperature detection means 4 varies depending on the degree and location of the holes and cracks.

Furthermore, recent instantaneous water heaters have become space-saving due to the cramped housing situation in Japan, and forced combustion type models with a thin and compact design that can be installed close to the wall have been developed; When a water heater is equipped with a safety device like the conventional technology mentioned above,
Since a space A' having a relatively large volume is required to surround the body plate part 1a of the heat exchanger 1 with the cover 2, the depth dimension b' of the heat exchanger part increases, and the depth dimension B of the casing 5 increases. ′ increases accordingly, and at the same time, as the space A′ is filled with combustion gas as described above, the temperature becomes high, and the surface temperature of the casing 5 installed close to the wall W also rises, making it difficult to prevent fires. From this point of view, the separation distance L' between the wall surface of the wall W and the back surface of the casing 5 is also subject to its own limitations, making it difficult to achieve a thin and compact design that meets the market need for space saving mentioned above.

In addition, as a safety device against an abnormal temperature rise in the body plate portion 1a of the heat exchanger 1 when abnormal combustion such as dry firing occurs, the above-mentioned safety device against combustion gas leakage cannot be detected; Since the safety device (not shown) and the like mentioned at the beginning of the prior art must also be installed, there is a problem that the assembly work and structure become complicated.

The present invention improves the problems of the conventional technology as described above, and prevents holes in the body plate due to not only abnormal combustion such as dry firing but also thermal fatigue and corrosion due to repeated heating and cooling of the heat exchanger. The purpose of the present invention is to provide a safety device for an instantaneous water heater with a thin and compact design that operates reliably in an extremely short period of time even in the case of abnormal combustion in which cracks or cracks occur.

[Means for solving problems]

In order to achieve the above-mentioned purpose, the present invention
A front plate and a rear plate are fixed to both the front and rear sides of the body plate around which the water tubes constituting the heat exchanger are wrapped so as to be in contact with the water tubes through packing at the upper end and both left and right ends, and the front plate and the rear plate are A bulge portion having a closed lower end and an open upper end is formed approximately vertically in the center of the plate, and openings are provided above the bulge portions of the front plate and the rear plate, and any one of the openings is provided. Abnormal temperature detection means for detecting leakage of combustion gas is disposed in one opening, and abnormal temperature detection means for detecting dry heating of the heat exchanger is disposed in close contact with the body plate facing the other opening. It is characterized by having been established.

[Function] The safety device for the instantaneous water heater of the present invention has the above-described configuration, so that if a hole or crack occurs in the body plate, no matter where the hole or crack occurs, the bulge will occur at approximately the center. The combustion gas quickly reaches the abnormal temperature detection means through the section, which can prevent secondary disasters due to combustion gas leakage, and also prevents the occurrence of secondary disasters due to combustion gas leakage. It can be detected by the detection means, but the depth of the vessel is only a fixed front plate and a rear plate that have bulges at the front and rear of the body plate, and if combustion gas leaks. will detect this quickly, so
To obtain a thin and compact instantaneous water heater suitable for installation close to a wall without any problem even if the distance between the container body and the wall is shortened.

〔Example〕

Hereinafter, an embodiment of an instantaneous water heater to which the present invention is applied will be described based on FIGS. 1 and 2.

FIG. 1 is a longitudinal sectional side view showing an embodiment of an instantaneous water heater to which the present invention is applied, and FIG. 2 is an exploded perspective view of the main parts.

In FIGS. 1 and 2, reference numeral 1a denotes a body plate portion to which a heat exchanger 1 is fixed at the upper end, and a water pipe 6 is wound around the outer periphery of the body plate portion. 5 is a casing; 7 is a burner disposed at the lower part of the combustion chamber surrounded by the body plate portion 1a;
Reference numeral 8 indicates a forced combustion fan disposed below the fan, and reference numeral 9 indicates an exhaust stack.As is well known, when the fan 8 is driven to burn the burner 7, the water supplied from the water supply pipe 10 is mainly sent to the heat exchanger. 1, and the hot water is discharged from the hot water supply pipe 11.

In the present invention, heat-resistant packing 12 is attached to the upper ends and both left and right ends of the front and rear surfaces of the body plate portion 1a (the packing on the rear surface is not shown in FIG. 2), and the A front plate 13 and a rear plate 14 are fixed to the front and rear surfaces of the body plate portion 1a with screws or the like so as to be in substantially contact with the water pipe 6.

The front plate 13 and the rear plate 14 have a vertically elongated bulge 15 formed approximately at the center thereof with a closed lower end 15a and an open upper end 15b, and the front plate directly above the bulged portion 15. Openings 16 are formed in the plate portion and the rear plate portion. A presser plate 17 screwed to the front plate 13 is provided in the opening 16 of the front plate 13.
The means 18 for detecting abnormal temperature during dry firing, such as a temperature fuse, is attached so as to be in close contact with the body plate 1a.
In addition, an abnormal temperature detection means 19 such as a temperature fuse is provided in the opening 16 of the rear plate 14 to detect combustion gas leakage due to a hole or crack (this detection means 19 is located in the body plate). 1a), both abnormal temperature detection means 18, 19
For example, they are connected in series and connected to the circuit of the abnormal condition notification device and the solenoid valve. In the illustrated embodiment, the abnormal temperature detection means 18 at the time of dry firing is provided on the front plate 13 side, and the abnormal temperature detection means 19 at the time of combustion gas leakage is provided on the rear plate 14 side. , these may be arranged in reverse.

The safety device for the instantaneous water heater of the present invention has the above-mentioned configuration, so that when the water heater is dry-heated, the abnormal temperature detection means 18 disposed in close contact with the body plate immediately detects the abnormal temperature, and also prevents holes from forming. If a crack occurs and combustion gas leaks, the abnormal temperature detecting means 19 can detect and notify this, and the electromagnetic valve circuit can be shut off to stop the fuel supply. In the present invention, especially when combustion gas leaks, a bulge with a lower end closed and an upper end opened is formed vertically at approximately the center of the front plate or rear plate, and close to the upper end opening. Since the abnormal temperature detection means 19 is provided, the combustion gas can quickly reach the upper end opening via the bulged portion, regardless of the location of the hole or crack that occurs in the body plate. Therefore, detection of combustion gas leakage can be performed extremely quickly and with stable performance. Since the instantaneous water heater equipped with the device of the present invention simply has a front plate and a rear plate that partially have a bulge and are fixed so as to be in contact with the water pipes, the depth dimension b of the heat exchange part is As the size is reduced, the depth dimension B of the case 5 is also reduced accordingly, and
When combustion gas leaks, it is detected promptly as described above, so the temperature of the casing 5 does not increase due to the leakage of combustion gas, and therefore, the distance between the wall surface of the wall W and the back surface of the casing 5 is reduced. There is no need to take a particularly large distance L, and as a result, a thin and compact forced combustion instantaneous water heater that can be installed close to a wall surface can be obtained.

[Effect of idea]

As described above, according to the present invention, if a hole or crack occurs in the body plate, it can be detected immediately regardless of its location, and it can also be detected when the fire is dry. Moreover, it is possible to obtain an instantaneous water heater that can be installed close to a wall surface by making the depth dimension of the container thin, even though it has both of the above-mentioned abnormal temperature detection functions.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view showing an example of a forced combustion instantaneous water heater to which the present invention is applied, and FIG. 2 is an exploded perspective view of the main parts. FIG. 3 is a longitudinal sectional side view similar to FIG. 1 showing a conventional example. DESCRIPTION OF SYMBOLS 1...Heat exchanger, 1a...Body plate part, 5...Housing, 6...Water tube, 7...Burner, 8...Fan,
12...Packing, 13...Front plate, 14...Rear plate, 15...Bulging portion, 15b...Top opening, 16
. . . Opening portion, 17 .

Claims (1)

[Scope of utility model registration request] A front plate and a rear plate are fixed to both front and rear surfaces of a body plate wrapped with water tubes constituting a heat exchanger so as to be in contact with the water tubes through packing at the upper end and both left and right ends, and the front plate and the rear plate are A bulge having a closed lower end and an open upper end is formed approximately vertically in the center of the plate, an opening is provided above the bulge in the front plate and the rear plate, and any one of the openings is provided. Abnormal temperature detection means for detecting leakage of combustion gas is disposed at one opening, and abnormal temperature detection means for detecting dry heating of the heat exchanger is disposed in close contact with the body plate facing the other opening. A safety device for instantaneous water heaters, which is characterized by the following: