JPH0791748A - Overheating preventing device of combustion equipment - Google Patents

Abstract

PURPOSE:To increase a contact area and assure a rapid operation of a flat thermal fuse by a method wherein a metallic plate of the flat thermal fuse is contacted with a heat shielding plate at a rear surface of a dimple part having metallic soluble wires of low melting point and at the same time contacted with the heat shielding plate also at the rear surface part of the dimple part. CONSTITUTION:A plurality of dimple stripes 13 held between a of projections 12 and 12 are press formed in parallel from each other at one surface of a metallic plate 1 having an insulating thin film 11 of better heat transfer characteristic at least one surface and at the same time some dimple portions 130 are press formed between the adjoining groups of projections 12. Soluble metallic wires 6 of low melting point are stored in the dimple stripes 13 through flax, both ends of each of the soluble metallic wires 6 are connected to an end part of a bridge conductive member with a soldering and the like and at the same time resin sealing material such as epoxy resin is molded to the dimple stripes 13 so as to constitute a desired flat thermal fuse. Then, the other surface of the metallic plate 1 is contacted with and fixed to a heat shielding plate 98 and then the dimple part 13 and the rear surface of the dimple part 130 are closely contacted with the rear surface of the heat shielding plate 98 and then the fuse is fixed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overheat prevention device for combustion equipment such as an instantaneous water heater.

[0002]

2. Description of the Related Art In a combustion apparatus such as an instantaneous water heater, rapid fatigue and frequent repetition of heating and cooling cause early thermal fatigue of the body of the combustion chamber. Corrosion of the body plate due to corrosive components also overlaps, holes may open in the body plate, and there is a fear that the combustion gas in the body plate will be ejected to the outside, which may cause a secondary disaster. .

In order to eliminate such a risk, a heat shield plate is arranged between the back surface of the combustion chamber body plate portion and the outer casing, and the heat shield plate shown in FIGS. [(A) Roll cross-sectional view], that is, the meandering groove 13 'is press-formed on one surface of the metal plate 1'provided with an insulating film 11' having good heat conductivity on one surface. Then, the low melting point fusible metal wire 6'is housed in the groove 13 ', and the insulating coating layer 8'is formed on one side of the metal plate.
The sheet-like temperature fuse provided with is attached to the back surface of the heat shield plate 98 'on the other surface of the metal plate 1', and the heat shield plate 98 'prevents the jetted combustion gas from contacting the wall surface and shields the same. It has been proposed that the sheet temperature fuse be actuated by the contact of the jetted combustion gas with the hot plate 98 ', and the gas supply solenoid valve is closed by microcomputer control to stop the gas combustion.

In the above-mentioned sheet temperature fuse, the groove 1 is used.
Since the low melting point fusible metal wire 6'is housed in 3 ', it is easy to position the low melting point fusible metal wire 6'when manufacturing the temperature fuse. When mounting on a combustion device or during transportation. Even if another object collides with the low melting point metal wire 6 ′, the low melting point metal wire 6 ′ is broken even if the insulating coating layer 8 ′ is thin such as a coating film. It has the advantage of being able to prevent

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the operating process of the gas, when the combustion gas ejected from the body plate opening comes into contact with the heat shield plate 98 ', the heat of the jet combustion gas 98' and the heat shield plate 98 'and the metal plate 1 of the planar temperature fuse are used. It is that the low melting point fusible metal wire 6'is melted by being transferred to the sheet temperature fuse through the contact interface with the'and the transferred heat. However, the contact between the metal plate 1 of the above-mentioned sheet temperature fuse and the heat shield plate 98 'is made only in the convex strip 131' on the rear surface of the groove 13 ', and the metal plate 1 and the heat shield plate 98'. Is mostly separated by a gap, the contact area between them is extremely small, and the heat transfer from the heat shield plate 98 'to the metal plate 1'of the sheet temperature fuse is poor, It is difficult to operate quickly.

An object of the present invention is to prevent the abnormal overheating of the combustion equipment by attaching a sheet temperature fuse to a heat shield plate which blocks the flight of the combustion gas ejected from the body plate opening of the combustion equipment. In this case, even though the low temperature melting metal wire accommodated in the recess of the metal plate is used for the planar temperature fuse, the metal plate and the heat shield plate can be brought into contact with each other in a large area. It is an object of the present invention to provide an overheat prevention device for a combustion device which can ensure a quick operation of the sheet temperature fuse.

[0007]

SUMMARY OF THE INVENTION An overheat prevention device for a combustion device according to the present invention has a metal plate having an insulating film on at least one surface thereof. A planar temperature fuse is provided by inserting a concave portion between the opposing convex stripes of the adjacent concave stripes, accommodating a low melting point metal wire in each concave stripe, and providing an insulating coating for sealing the concave stripes. The other surface of the plate is in contact with and fixed to the heat shield plate of the combustion device.

[0008]

The function is not only that the metal plate of the sheet temperature fuse is in contact with the heat shield plate at the back surface of the recess containing the low melting point soluble metal wire, but also at the back surface of the recess. Contact is made, and the contact area of the latter can be made significantly larger than the contact area of the former, and quicker operation is possible compared to the conventional example in which the planar temperature fuse is operated only by heat transfer by the former contact. Becomes

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1A to 1D are plan views showing a planar temperature fuse used in the present invention in a manufacturing process. FIG. 1E is a plan view of FIG. 1C. -E cross-sectional view is shown, and (f) of FIG. 1 and (to) of FIG. 1 respectively show the cross-sectional view and the cross-sectional view of FIG. 1 (d).

In FIG. 1 (a) to FIG. 1 (g),
Reference numeral 1 denotes a metal plate, which is shown in FIG.
(B) [a cross-sectional view taken along line (a) of FIG. 2], a pair of ridges 12, on one side of the metal plate 1 having the insulating thin film 11 having good thermal conductivity on at least one side, A plurality of recessed strips 13 sandwiched between 12 are press-formed in parallel, and a recess 130 is press-formed between the mutually facing projecting strips between the adjacent recessed strips 13, 13. In (a) of FIG.
Reference numerals 14 and 14 denote flat portions on both ends of one side of the metal plate, and 15 ... Bind holes. As the metal plate 1, a press-formed aluminum plate having an oxide film formed by alumite treatment can be used.

In FIG. 1A, reference numeral 21 (22) is a first insulating plate member, which is a bridge conductor for connecting the low melting point fusible metal wires in series on one surface of the insulating plate.
211 (221) is fixed, and a lead conductor 222 is also fixed to one side of the first insulating plate member 22. 15, ... are binding holes.

In FIGS. 1B to 1D,
31 (32) is a second insulating plate member, and the cutout 31
1 (321, 322, 322) and has a first insulating plate member 21.
(22) Overlaid on top. 15, ... are binding holes.

At the manufacturing stage shown in FIG.
One side 11 of the metal plate 1 is directed to the upper side, and the first insulating plate members 21 and 22 are conductors (bridge conductors) on both end flat portions.
211, 221 and lead conductor 222) are arranged with the fixed surface facing upward.

At the manufacturing stage shown in FIG. 1B,
Each first insulating plate member 21 (2) in FIG.
2) Each second insulating plate member 31 (32) is laminated on top, and the laminated body of the first insulating plate member and the second insulating plate member is passed through the binding holes 15 and 15 and rivets. It is fixed to the metal plate 1 by (not shown). At this stage, each notch 31 of the second insulating plate member 31 (32)
1, 321, 322, 322 to the first insulating plate member 21 (2
2) The ends 211a and 221a of the bridge conductors 211 and 221 or the ends 222a of the lead conductor 222 are exposed.

At the manufacturing stage shown in FIG. 1C,
As shown in (e) of FIG. 1, the flux 5 (having a lower melting point than the low melting point fusible metal wire 6 described later) is provided in the recess 13 of the metal plate 1.
, And the low melting point fusible metal wires 6 are housed in the flux-attaching concave lines, and both ends of each low melting point fusible metal wire 6 are bridge conductor ends 211a of the first insulating plate member 21 (22).
221a is connected by soldering or welding, and the lead wires 7, 7 are connected to the lead wire conductor ends 222a, 222a by soldering or welding. Thus, the low melting point metal wire 6. ... and the lead wires 7, 7 are electrically connected in series. The flux 5 may be adhered intermittently at regular intervals in the recessed line 13 in the longitudinal direction.

At the manufacturing stage shown in FIG. 1D,
As shown in (f) and (g) of FIG. 1 with respect to the semi-finished product shown in (c) of FIG. 1, a resin sealing material 8, such as an epoxy resin adhesive, is applied to the recessed ridges 13. And the low melting point fusible metal wire 6 and the flux 5 are sealed and the bridge conductor ends 211a and 221a of the first insulating plate member 21 (22) and the lead wire conductor ends 222a. Are insulated by a resin mold 81.

FIG. 3A is a sectional view showing an embodiment of an overheat prevention device for a combustion device according to the present invention. In FIG. 3A, 91 is a gas burner, 92 is a fan, and 9
Reference numeral 3 is a body plate portion provided on the gas burner 91, and the interior of the body plate portion 93 is a combustion chamber. Reference numeral 94 is a heat exchanger attached to the upper part of the combustion chamber, and 95 is a combustion gas outflow pipe. When the combustion gas passes through the heat exchanger 94, water is heated and flows in the heat exchanger 94. Go. Reference numeral 961 is a water supply pipe to the heat exchanger 94, and 962 is a hot water supply pipe from the heat exchanger 94, which is wound around the combustion chamber. An outer casing 97 is provided with a slit 971 for sucking air in front of the combustion chamber. Reference numeral 98 is a heat shield plate disposed between the back surface (wall surface side) of the body plate portion 98 and the outer casing 97. A is the above-mentioned sheet temperature fuse, and FIG.
(B), the other surface of the metal plate 1 is in contact with and fixed to the back surface of the heat shield plate 98, and the back surface portion of the recessed strip 13 accommodating the low melting point soluble metal wire 6 and the recess 130. The back surface portion is in close contact with the back surface of the heat shield plate 98.

In (a) and (b) of FIG. 3, a hole is opened in the body plate portion 93, and combustion gas is ejected from the opening. When the ejected combustion gas comes into contact with the heat shield plate 98, the combustion gas The heat is transferred to the surface temperature fuse A through the contact interface between the heat shield plate 98 and the metal plate 1 of the surface temperature fuse A, and the low melting point fusible metal wire 6 is fused by the transferred heat, The signal current is cut off, the gas supply solenoid valve of the gas burner 91 is closed, and the combustion is stopped.

In this case, the metal plate 1 having the sheet temperature fuse A
Since the other surface is in close contact with the heat shield plate 98 on almost the entire surface except the back side portions of the pair of protrusions 12, 12 that sandwich the low melting point soluble metal wire accommodating recess strip 13, from the heat shield plate 98 The heat of the sheet temperature fuse A can be quickly transferred to the metal plate 1, and a quick operation can be guaranteed.

In the present invention, as shown in (a) and (b) of FIG. 4 [a cross-sectional view taken along line (a) of FIG. 4] in the planar temperature fuse, good thermal conductivity is provided on at least one surface. Pair of ridges 1 on one side of the metal plate 1 provided with a conductive insulating film 11
A concave strip 13 is formed between the ridges 12 and 12 by press-molding the ridges 2 and 12 in a meandering shape. The flux 5 and the low melting point fusible metal wire 6 are accommodated in the meandering ridge 13 and A resin sealing material 8 such as an epoxy resin adhesive is molded on the strip 13 to seal the flux 5 and the low melting point soluble metal wire 6, and the lead conductors 7 at both ends of the low melting point soluble metal wire, 7 is pulled out from the groove 13, and the sheet temperature
The other surface 111 of the metal plate 1 may be fixed in contact with the heat shield plate 98 of the combustion device.

[0021]

The overheat prevention device for the combustion equipment of the present invention is constructed as described above, and the metal sheet of the sheet temperature fuse is provided with the concave stripe, and the low melting point soluble metal wire is provided in the concave stripe. Despite being housed, the heat shield plate in the combustion equipment and the metal plate of the sheet temperature fuse can be almost in contact with each other, and efficient heat transfer from the heat shield plate to the sheet temperature fuse can be achieved. You can guarantee the transmission. Therefore, the low melting point fusible metal wire in the sheet temperature fuse can be arranged at intervals of high dimensional accuracy in the concave press molding, and
Combined with the advantage that the low melting point fusible metal wire can be prevented from breaking even when other objects collide with the surface temperature fuse on the heat shield plate or during transportation, it has excellent reliability. An overheat prevention device can be provided.

[Brief description of drawings]

1A to 1D are explanatory views showing an example of a planar temperature fuse used in the present invention in a manufacturing process,
1 (e) is a sectional view taken along the line hoe in FIG. 1 (c), and FIG. 1 (f) and FIG. 1 (t) are sectional views taken along the line hoe in FIG. 1 (d). FIG.

2 (a) is a plan view showing the metal plate in the sheet temperature fuse of FIG. 1, and FIG. 2 (b) is a cross-sectional view taken along line (b) of FIG.

FIG. 3 (a) is an explanatory view showing an embodiment of the present invention,
FIG. 3B is an explanatory view showing a mounting state of the sheet temperature fuse in FIG.

4 (a) is an explanatory view showing another example of the sheet temperature fuse used in the present invention, and FIG. 4 (b) is a cross-sectional view taken along the line of FIG. 4 (a). is there.

5 (A) is an explanatory view showing a conventional example, and FIG. 5 (B) is a cross-sectional view taken along line (B) of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal plate 11 Insulating film 12 Convex strip 13 Recessed strip 130 Recessed portion 5 Flux 6 Low melting point fusible metal wire 8 Sealing resin 98 Heat shield plate

Claims (1)

[Claims] 1. A metal plate having an insulating film on at least one surface thereof is provided with a plurality of parallel recesses sandwiched by a pair of projections on one surface and between adjacent projections between adjacent recesses. A low temperature melting metal wire is placed in each groove with a recess interposed, and a sheet temperature fuse with an insulating coating that seals the groove is used as a heat shield plate for combustion equipment on the other side of the metal plate. An overheat prevention device for combustion equipment, which is characterized by being fixed in contact.