JP2019066115A - Water heater - Google Patents

Abstract

To eliminate a risk of malfunction due to damage of a conductive pattern even in a case of winding a resin sheet outside a portion where contact may occur.SOLUTION: In a water heater, a resin sheet 20 comprises a redundant part 26 where in a state of winding the resin sheet around a combustion chamber 6, a region opposite to a predetermined portion (herein, a clip) outside the combustion chamber 6 is a non-detection region 28 where a conductive pattern 21 is not printed, and that in the state of winding the resin sheet around the combustion chamber 6, is overlapped with the outside of the non-detection region 28, and overlaps with the non-detection region 28 a detection region 22 where the conductive pattern 21 is printed.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a water heater equipped with an overheat prevention device that accommodates a combustion chamber provided with a burner and a heat exchanger inside a casing and detects abnormal overheating of the combustion chamber to stop operation.

The water heater connects the water supply pipe and the hot water discharge pipe to the heat exchanger heated to the burner, and is supplied from the water supply pipe through the external water pipe by opening the external hot water supply tap to which the hot water discharge pipe is connected. It is equipped with a hot water supply circuit that heats the water by heat exchange with the combustion exhaust of the burner and discharges it.
In such a water heater, the combustion chamber in which the burner is disposed at the lower part and the heat exchanger is disposed at the upper part is accommodated in the inside of the casing, however, cracking due to abnormal overheating occurs in the casing forming the combustion chamber. In order to detect this and stop the combustion of the burner, an overheat prevention device is provided. As disclosed in Patent Document 1, this overheat prevention device forms a conductive pattern on the surface of a resin sheet that melts at a set temperature, and arranges the conductive pattern so as to wind the outer periphery of the casing of the combustion chamber. The one connected to the controller is known. That is, if the combustion chamber is cracked or punctured due to abnormal overheating and the combustion exhaust gas spouts from it, the conductive pattern breaks with the melting of the resin sheet, and the resistance value increases rapidly or becomes infinite, thus the resistance value The controller, which has detected a change in the power supply, shuts off the fuel gas supply to extinguish the burner.

Unexamined-Japanese-Patent No. 10-122563 gazette

In recent hot water heaters, the housing tends to be compact due to the demand for space saving. Therefore, in the housing, it is necessary to arrange the pipes such as the water supply pipe and the hot water discharge pipe in a narrow space between the combustion chamber and the like, and the number of bent portions is increased. For this reason, the pipe is divided into a plurality of pieces, and a structure in which the pipe is connected from the outside using a connecting member such as a clip is adopted.
However, in this case, since the connection member is exposed at the connection portion of the pipe, when the resin sheet wound around the outside of the connection member contacts, the conductive pattern is damaged and the resistance value changes, and the water heater malfunctions (combustion stop ) There was a risk of

  Therefore, the present invention has an object to provide a water heater capable of eliminating the possibility of malfunction due to the damage of the conductive pattern even if the resin sheet is wound on the outside of a portion having a possibility of contact such as a connecting member of piping. The

In order to achieve the above object, the invention according to claim 1 comprises, in a housing, a combustion chamber having a burner and a heat exchanger, and a controller for controlling the combustion of the burner, while being accommodated in the combustion chamber. A water heater provided with an overheat prevention device for stopping burning of the burner when the resin sheet on which the conductive pattern is printed is wound and the controller detects a change in resistance value due to damage to the conductive pattern,
The resin sheet has a region facing a predetermined portion outside the combustion chamber in the winding state to the combustion chamber as a non-detection region where the conductive pattern is not printed, and a non-detection region in the winding state to the combustion chamber. It has a surplus length which overlaps outside and makes a detection field where a conductive pattern is printed overlap a non-detection area.

  According to the first aspect of the present invention, the resin sheet is provided with the non-detection area, and by providing the extra length portion overlapping the non-detection area in the wound state to overlap the detection area, there is a fear of contact Even if the resin sheet is wound outside a certain portion, since the non-detection area contacts, the risk of malfunction due to the damage of the conductive pattern can be eliminated. In addition, since the non-detection area is covered by the outside detection area, the detection performance of the overheat prevention device can be secured.

It is a perspective view of a water heater. It is a front view of the housing | casing which removed the front cover. It is a front view of the housing | casing which removed the resin sheet in FIG. It is an expanded view of a resin sheet. It is a perspective view which shows the state which winds a resin sheet in a combustion chamber (a housing | casing is abbreviate | omitted). It is the AA line expanded sectional view of FIG. It is an enlarged view of the front part of FIG.

Hereinafter, embodiments of the present invention will be described based on the drawings.
FIG. 1 is a perspective view showing an example of a water heater. The water heater 1 has a vertically elongated box-like housing 2 whose upper and lower surfaces, left and right side surfaces and back surfaces are enclosed and the front surface is open, and a front cover 3 for closing the front surface of the housing 2 At the upper part of the cover 3, a horizontally long cylindrical exhaust port 10 provided in front of the exhaust hood 9 is protruded. .. Are provided at the lower part and the side part of the front cover 3, and brackets 5, 5 for attachment to a wall or the like are attached to the upper and lower sides of the rear face of the housing 2.

  FIG. 2 is a front view of the housing 2 with the front cover 3 removed. In the housing 2, a combustion chamber 6 is provided. The combustion chamber 6 is disposed on the upper side in the housing 2 and has a rectangular cylindrical lower casing 7 accommodating a burner unit consisting of a plurality of burners, and a rectangular cylindrical upper casing 8 accommodating a heat exchanger. And an exhaust hood 9 in which an exhaust port 10 is projected forward on the upper side of the upper casing 8. Piping 12, 12 ... (water supply pipe, hot water discharge pipe, bath return pipe, bath) connected to the external piping through the connection ports 11, 11 ... provided on the lower surface of the casing 2 on the left and right of the upper casing 8 Forward pipe) is connected. At the opening of the housing 2 at the lower part of the combustion chamber 6, a controller 13 formed by housing an electrical component board in a rectangular box in a front view is installed horizontally.

  Here, the piping 12 (in this case, the tapping pipe) routed to the front side of the upper casing 8 is, as shown in FIG. 3, an upper portion 14 that is routed forward from the upper casing 8 and the front of the upper casing 8 It is divided into a lower part 15 which is drawn downward across the lower part and connected by a clip 16 as a connecting member in front of the upper casing 8.

In this water heater 1, when the hot water supply tap of the external piping connected to the hot water discharge pipe is opened and water flows from the water supply pipe into the appliance, the controller 13 burns the burner unit and the water in the heat exchanger Heat exchange with the combustion exhaust of the burner. The heated hot water is discharged from the hot water tap through the hot water outlet pipe and the external piping.
In addition, when the automatic switch of the hot water supply remote control or bath remote control externally connected to the controller 13 is pressed, the controller 13 supplies hot water from the hot water discharge pipe to the bathtub through the drop-in pipe connecting the hot water discharge pipe and the bath return pipe. Do.

  The resin sheet 20 is wound around the combustion chamber 6. The resin sheet 20 is a band-like body wound around the combustion chamber 6 so as to straddle the lower casing 7 and the upper casing 8 and, as shown in FIG. A continuous conductive pattern 21 extending in the direction is printed over the entire length in the longitudinal direction to form a detection area 22 with the entire conductive pattern 21. At the lower edge of one end (the right side in FIG. 4) of the resin sheet 20, terminal portions 23 for electrically connecting the harness to both ends of the conductive pattern 21 are provided. At the ends, locking pieces 24 are formed vertically by a pair of L-shaped slits.

The entire length in the longitudinal direction of the resin sheet 20 is longer than the length of one rotation around the outside of the combustion chamber 6, and the circumferential portion 25 for one rotation around the combustion chamber 6 including the end portion on the locking pieces 24, 24. And an extra length portion 26 exceeding one round. At the boundary between the orbiting portion 25 and the extra length portion 26, slits 27, 27 in which the locking pieces 24, 24 can be locked are formed vertically.
In addition, at the upper end of the terminal portion 23 at the end portion of the circumferential portion 25 on the locking pieces 24, 24, the meandering length in the width direction of the conductive pattern 21 is shortened, so that the conductive pattern 21 is not printed. Region 28 is formed.

  As shown in FIG. 5, the resin sheet 20 is disposed such that the non-detection area 28 is located on the right front side of the upper casing 8 and at the front of the clip 16 of the pipe 12. The winding portion 25 is wound around the combustion chamber 6 as it is. Then, as shown in FIGS. 6 and 7, the rounded extra length portion 26 is superimposed on the circumferential portion 25 on the front side of the upper casing 8, and the locking pieces 24, 24 of the circumferential portion 25 are engaged with the slits 27, 27. Then, it is fixed in the circulation state of the combustion chamber 6. In FIGS. 6 and 7, reference numeral 17 denotes a heat exchanger, which includes a heat transfer pipe 19 penetrating a plurality of fins 18 in a serpentine manner, and a pipe 12 is connected to both ends.

Reference numeral 29 denotes a receiving plate which is screwed to the front surface of the lower casing 7 and guides the connection of the harnesses 30, 30 from the controller 13 to the terminal portion 23 and receives the resin sheet 20. In the front side, the resin sheet 20 is held at a predetermined height by placing the extra length portion 26 on the step portion 31 formed on the front side.
Thus, in the wound state of the resin sheet 20, the non-detection region 28 of the circumferential portion 25 is located on the front side of the clip 16, and the detection region 22 of the extra length portion 26 overlaps on the front side. Over the circumference, the detection area 22 is covered to form an overheat prevention device in which the resistance value of the conductive pattern 21 is monitored by the controller 13.

In the water heater 1 configured as described above, in the wound state of the resin sheet 20, the non-detection region 22 where the conductive pattern 21 is not formed is opposed to the position of the clip 16 of the pipe 12, so the clip 16 Is in contact with the non-detection area 22, and damage to the non-detection area 22 does not affect the conductive pattern 21.
Then, when the combustion exhaust is spouted due to cracking or perforation in the lower casing 7 or the upper casing 8 of the combustion chamber 6, the resin sheet 20 is melted and the conductive pattern 21 is broken, and the resistance value increases rapidly or becomes infinite. Become. The controller 13 having detected this closes the gas solenoid valve for opening and closing the gas flow path to the burner unit to shut off the supply of the fuel gas and stop the combustion of the burner unit.

  Thus, according to the water heater 1 of the above embodiment, the resin sheet 20 electrically conducts the region facing the predetermined portion (here, the clip 16) outside the combustion chamber 6 in the winding state to the combustion chamber 6 The pattern 21 is not printed as a non-detection area 28 and overlaps the outside of the non-detection area 28 in a winding state to the combustion chamber 6, and the detection area 22 where the conductive pattern 21 is printed is overlapped with the non-detection area 28 Since the non-detection region 28 contacts even if the resin sheet 20 is wound on the outside of the clip 16 having a possibility of contact, there is no possibility of malfunction due to damage to the conductive pattern 21 because the extra length portion 26 is provided. be able to. Further, even if the non-detection area 28 is provided, the detection performance of the overheat prevention device can be secured because the non-detection area 28 is covered by the outside detection area 22.

In the above embodiment, the non-detection area is made to face one clip, but if there are a plurality of clips, a plurality of non-detection areas may be provided. Moreover, as a site | part which makes a non-detection area | region oppose, it may be not only the connection member (clip) of piping but other site | parts, such as a bimetal switch attached to a heat exchanger tube. Therefore, the position, size, and range of the non-detection area can be appropriately changed according to the part to be opposed.
Further, the detection area is not limited to the above-described form, and the meandering distance, the direction, and the like of the conductive pattern can be appropriately changed, and it is not necessary to form one conductive pattern. The upper and lower widths of the resin sheet may be increased, and the fixing structure to the combustion chamber is not limited to the above embodiment.

  In addition, the configuration of the water heater itself is not limited to the above embodiment, but the one having a large left / right width of the casing, one having a heating circuit instead of the bath circuit, or one having only the hot water supply circuit Even if it does, this invention is applicable.

  1 · · · water heater, 2 · · · housing · 3 · · front cover, 6 · · · combustion chamber, 7 · · lower casing, 8 · · upper casing, 12 · · piping, 13 · controller, 16 · · · · 17 heat exchanger 20 resin sheet 21 conductive pattern 22 detection area 25 circumferential part 26 extra length 28 non-detection area.

Claims (1)

A housing contains a combustion chamber having a burner and a heat exchanger, and a controller for controlling the combustion of the burner.
A hot water supply equipped with an overheat prevention device for stopping combustion of the burner when the resin sheet on which a predetermined conductive pattern is printed is wound around the combustion chamber and the controller detects a change in resistance due to damage to the conductive pattern. And it is
The resin sheet has a region facing a predetermined portion outside the combustion chamber in a winding state to the combustion chamber as a non-detection region where the conductive pattern is not printed, and a winding state to the combustion chamber And a surplus portion overlapping the outside of the non-detection area and causing the detection area on which the conductive pattern is printed to overlap the non-detection area.

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