JP6874325B2 - Hot water device - Google Patents

Description

The present invention relates to a water heating device, and more particularly to a water heating device including a burner and a heat exchanger.

A water heating device including an ignition plug having a plurality of electrodes is disclosed in, for example, Japanese Patent Application Laid-Open No. 7-190359 (Patent Document 1). In the spark plug of this water heating device, a plurality of electrodes are held at a base (insulator portion) at intervals from each other. This insulator portion is arranged on the side plate (wall surface) of the case of the gas combustion burner device.

Japanese Unexamined Patent Publication No. 7-190359

In the spark plug described in the above publication, the condensed water generated on the wall surface of the case drops and adheres to the insulator portion. There is a problem that insulation failure occurs between the two electrodes due to the two electrodes conducting each other due to the condensed water.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a water heating device capable of suppressing the occurrence of poor insulation between two electrodes.

The water heating device of the present invention includes a burner, a heat exchanger, and a spark plug. The burner generates combustion gas for heating. The heat exchanger is provided below the burner and heats hot water with combustion gas. The spark plug ignites the burner. The heat exchanger includes a case. The case has a wall surface that separates the inside from the outside. The spark plug includes an insulator and two electrodes. The insulator part is attached to the wall surface of the case. Each of the two electrodes extends from the inside to the outside of the case through the insulator portion and is arranged laterally spaced apart from each other. The insulator portion includes a base end portion and a tip end portion. The base end is attached to the wall of the case. The tip portion projects from the base end portion to the side opposite to the wall surface. The tip portion has a tip surface and a groove portion. The tip surface is arranged on the side opposite to the base end portion. The groove portion is recessed from the tip end surface toward the base end portion. The groove portion is arranged between the two electrodes and is provided from the upper end to the lower end of the tip portion. The width of the groove in the lateral direction narrows from the upper end to the lower end of the tip portion.

According to the water heating device of the present invention, the groove portion is recessed from the tip end surface toward the base end portion, is arranged between the two electrodes, and is provided from the upper end to the lower end of the tip portion. The width of the groove in the lateral direction is narrowed from the upper end to the lower end of the tip portion. As a result, the condensed water generated on the wall surface and dripping and adhering to the insulator portion easily flows into the groove portion. Therefore, it is possible to prevent the two electrodes from conducting each other by connecting the two electrodes with the condensed water collected at the upper end of the tip portion. Therefore, it is possible to prevent the occurrence of poor insulation between the two electrodes.

In the above water heating device, the width of the groove portion increases from the base end portion to the tip end surface. As a result, the condensed water is less likely to collect at the upper end of the tip from the base end toward the tip surface. Therefore, the condensed water collected at the upper end of the tip connects the two electrodes to each other, so that the two electrodes conduct with each other. This can be further suppressed.

In the above water heating device, the tip portion includes, in the lateral direction, one end portion arranged on one side of the groove portion and the other end portion arranged on the other side of the groove portion. One end has a downward slope with a lower height on the opposite side of the other end. The other end has a downward slope with a lower height on the opposite side of the other end. As a result, the dew condensation water adhering to one end can be flowed to the side opposite to the other end, and the dew condensation water adhering to the other end can be flowed to the side opposite to the one end. Therefore, the condensed water is less likely to collect at the upper end of the tip portion. Therefore, it is possible to further prevent the two electrodes from conducting each other by connecting the two electrodes with the condensed water collected at the upper end of the tip portion.

In the above water heating device, the groove includes an inclined wall portion provided at the upper end of the tip portion. The inclined wall portion has a downward slope whose height decreases in a plane from the upper end to the lower end of the tip portion. As a result, the dew condensation water can easily flow through the groove portion by flowing the dew condensation water along the downward slope in which the height is lowered in a plane shape of the inclined wall portion.

In the above-mentioned water heating device, the inclined wall portion is provided so as to surround the electrode in the circumferential direction of the electrode and to be a tangent to a virtual circle in which the electrode is located at the center. Therefore, by setting a virtual circle so as to secure the insulating property, it is possible to facilitate the flow of condensed water along the inclined wall portion while ensuring the insulating property.

In the above water heating device, the groove includes an inclined wall portion provided at the upper end of the tip portion. The inclined wall portion has a downward slope in which the height decreases in a curved shape from the upper end to the lower end of the tip portion. As a result, the dew condensation water can easily flow through the groove portion by flowing the dew condensation water along the downward slope in which the height is lowered in the curved surface shape of the inclined wall portion.

In the above water heating device, the tip portion includes two cylindrical portions. Each of the two electrodes is inserted into each of the two cylindrical portions in the axial direction of the cylindrical portion. The groove portion is arranged between the two cylindrical portions. As a result, the condensed water can flow into the groove portion arranged between the two cylindrical portions. Further, each of the two electrodes can uniformly secure the insulating property in the radial direction of the cylindrical portion.

In the above water heating device, the tip portion includes a connecting wall arranged between the two cylindrical portions. Each of the two cylindrical portions projects from the base end portion to the side opposite to the wall surface from the connecting wall. The upper end of the connecting wall has a downward slope with a lower height from the base end to the side opposite to the wall surface. As a result, the condensed water can easily flow through the groove by flowing the condensed water along the connecting wall.

In the above water heating device, the tip portion protrudes from the base end portion into the inside of the case. The groove is arranged inside the case. As a result, it is possible to prevent the two electrodes from conducting each other by connecting the two electrodes with the condensed water accumulated at the upper end of the tip portion inside the case.

In the above water heating device, the tip portion protrudes from the base end portion to the outside of the case. The groove is arranged on the outside of the case. As a result, it is possible to prevent the two electrodes from conducting each other by connecting the two electrodes with the condensed water collected at the upper end of the tip portion outside the case.

In the above water heating device, the tip portion protrudes from the base end portion both inside and outside the case. Grooves are located both inside and outside the case. The depth of the groove arranged inside the case is larger than the depth of the groove arranged outside the case. As a result, it is possible to prevent the two electrodes from conducting each other by connecting the two electrodes with the condensed water accumulated at the upper end of the tip portion both inside and outside the case. In addition, the amount of dew condensation water generated inside the case is larger than that of dew condensation water generated outside the case. Therefore, since the depth of the groove arranged inside the case is larger than the depth of the groove arranged outside the case, a large amount of dew condensation water generated inside the case can flow into the groove. .. Therefore, it is possible to effectively prevent the two electrodes from conducting each other by connecting the two electrodes with the condensed water accumulated at the upper end of the tip portion inside the case where a large amount of condensed water is generated.

As described above, according to the present invention, it is possible to provide a water heating device capable of suppressing the occurrence of insulation failure between two electrodes.

It is a figure which shows typically the structure of the hot water apparatus in one Embodiment of this invention. It is a perspective view which shows typically the structure of the sensible heat recovery heat exchanger and the latent heat recovery heat exchanger in one Embodiment of this invention. It is a perspective view which shows schematic structure of the sensible heat recovery heat exchanger in one Embodiment of this invention. It is sectional drawing which shows schematic the structure of the sensible heat recovery heat exchanger in one Embodiment of this invention. FIG. 5 is an enlarged cross-sectional view showing the vicinity of the spark plug in FIG. 4 in an enlarged manner. It is a figure seen from the direction of arrow A of FIG. It is a perspective view which shows the structure seen from the side arranged outside the case of the spark plug in one Embodiment of this invention. It is a perspective view which shows the structure seen from the side arranged inside the case of the spark plug in one Embodiment of this invention. It is an enlarged front view which shows the vicinity of the spark plug in FIG. 2 in an enlarged manner. It is a front view which shows the structure seen from the side arranged inside the case of the spark plug in one Embodiment of this invention. It is a perspective view which shows the state which dew condensation water adhered to the spark plug in the comparative example. It is a perspective view showing a state in which dew condensation water has adhered to the ignition plug in an embodiment of the present invention. It is a front view which shows the 1st modification of a spark plug. It is a front view which shows the 2nd modification of a spark plug. It is a top view which shows the 3rd modification of a spark plug. It is a perspective view which shows the structure seen from the side arranged outside the case of the 3rd modification of a spark plug. It is a perspective view which shows the structure seen from the side arranged inside the case of the 3rd modification of a spark plug.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, the configuration of the water heating device according to the embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 1, the water heating device 100 of the present embodiment includes a sensible heat recovery heat exchanger (primary heat exchanger) 10, an ignition plug 14, and a latent heat recovery heat exchanger (secondary heat exchanger). 20, burner 30, chamber 31, blower 32, duct 33, venturi 34, orifice 35, gas valve 36, pipe 40, bypass pipe 41, three-way valve 42, liquid-liquid heat exchanger 43. It mainly has a hot water pipe 44 and a housing 50. Inside the housing 50, all the above-mentioned parts except the housing 50 are arranged.

The gas valve 36, the orifice 35 and the venturi 34 are connected to the pipe in this order. Fuel gas can be supplied to this pipe from the outside of the housing 50. The fuel gas supplied to this pipe flows to the venturi 34 through the gas valve 36 and the orifice 35.

The gas valve 36 is for controlling the flow rate of the fuel gas. The Venturi 34 increases the flow velocity of the mixed gas by narrowing the flow of the mixed gas of the fuel gas and the air. The Venturi 34 is configured so that air can be taken in from the outside of the housing 50. The Venturi 34 is configured to mix the air taken in from the outside of the housing 50 with the fuel gas supplied from the piping.

The Venturi 34 is connected to the blower 32 through a pipe. Through this pipe, the mixed gas mixed in the Venturi 34 is sent to the blower 32. The blower 32 is for sending the mixed gas to the burner 30. The blower 32 mainly has a fan case, an impeller arranged in the fan case, and a drive source (motor or the like) for rotating the impeller.

The blower 32 is connected to the chamber 31, and the chamber 31 is connected to the burner 30. The mixed gas delivered from the blower 32 is sent to the burner 30 through the chamber 31.

The burner 30 is for generating a combustion gas for heating by burning the mixed gas. The burner 30 is a back-combustion type device that supplies combustion gas downward. The mixed gas blown out from the burner 30 is ignited by the spark plug 14 and becomes a combustion gas. The spark plug 14 is attached to the sensible heat recovery heat exchanger 10 as described later.

The burner 30, the sensible heat recovery heat exchanger 10, and the latent heat recovery heat exchanger 20 are connected so that the combustion gas passes through the sensible heat recovery heat exchanger 10 and the latent heat recovery heat exchanger 20 in order. Each of the sensible heat recovery heat exchanger 10 and the latent heat recovery heat exchanger 20 is provided below the burner 30. Specifically, the sensible heat recovery heat exchanger 10 is attached below the burner 30, and the latent heat recovery heat exchanger 20 is attached below the sensible heat recovery heat exchanger 10.

A duct 33 is connected to the latent heat recovery heat exchanger 20, and the duct 33 extends to the outside of the housing 50. As a result, the combustion gas that has passed through the latent heat recovery heat exchanger 20 is discharged to the outside of the housing 50 through the duct 33.

Each of the sensible heat recovery heat exchanger 10 and the latent heat recovery heat exchanger 20 is for heating hot water with combustion gas. Specifically, each of the sensible heat recovery heat exchanger 10 and the latent heat recovery heat exchanger 20 is for heating hot water by exchanging heat between the combustion gas supplied from the burner 30 and hot water. Is.

The sensible heat recovery heat exchanger 10 is for recovering the sensible heat of the combustion gas generated by the burner 30. The latent heat recovery heat exchanger 20 is for recovering the latent heat of the combustion gas. For the latent heat recovery heat exchanger 20, for example, a plate type heat exchanger is used.

When the temperature of the hot water entering the sensible heat recovery heat exchanger 10 is low, or when the heating amount of the burner 30 is small, the water vapor of the combustion gas condenses in the sensible heat recovery heat exchanger 10, and condensed dew condensation occurs. Water (drain) is generated. Drain is also generated in the latent heat recovery heat exchanger 20. These drains are drained to the outside of the housing 50 through a part of the duct 33. Further, when the temperature of the air is high outside the sensible heat recovery heat exchanger 10 and the temperature of the hot water entering the sensible heat recovery heat exchanger 10 is low, water vapor in the air outside the sensible heat recovery heat exchanger 10 is formed. Condensed water is generated. That is, dew condensation water (drain) in which the water vapor of the combustion gas is condensed is generated inside the manifest heat recovery heat exchanger 10, and dew condensation water in which the water vapor in the air is condensed is generated outside the manifest heat recovery heat exchanger 10. appear. Condensation water is likely to occur in the endothermic pipe portion described later both inside and outside the sensible heat recovery heat exchanger 10.

The endothermic pipe of the sensible heat recovery heat exchanger 10 and the endothermic pipe of the latent heat recovery heat exchanger 20 are connected by a pipe 40. The portion of the pipe 40 on the water inlet side of the latent heat recovery heat exchanger 20 and the portion of the pipe 40 on the hot water outlet side of the sensible heat recovery heat exchanger 10 are bypassed by the bypass pipe 41.

The portion of the pipe 40 on the hot water outlet side of the sensible heat recovery heat exchanger 10 and the bypass pipe 41 are connected by a three-way valve 42. The three-way valve 42 is configured to be able to switch between a flow path from the sensible heat recovery heat exchanger 10 to the hot water outlet of the pipe 40 and a flow path from the sensible heat recovery heat exchanger 10 to the bypass pipe 41.

A liquid-liquid heat exchanger 43 is connected to the bypass pipe 41. A hot water pipe 44 connected to a hot water terminal is inserted into the liquid-liquid heat exchanger 43. The liquid-liquid heat exchanger 43 is configured so that hot water warmed through the sensible heat recovery heat exchanger 10 and the latent heat recovery heat exchanger 20 flows into the liquid-liquid heat exchanger 43. The hot water flowing inside the liquid-liquid heat exchanger 43 flows outside the hot water pipe 44, so that heat is exchanged between the hot water flowing inside the liquid-liquid heat exchanger 43 and the hot water flowing inside the hot water pipe 44. It becomes possible to do.

The water supplied to the hot water device 100 exchanges heat with the combustion gas in the sensible heat recovery heat exchanger 10 and the latent heat recovery heat exchanger 20 to become hot water. This makes it possible to supply hot water by the hot water device 100.

The hot water returned from the hot water terminal is warmed by heat exchange with the hot water warmed by the sensible heat recovery heat exchanger 10 and the latent heat recovery heat exchanger 20 in the liquid-liquid heat exchanger 43 through the hot water pipe 44. Is supplied to the hot water terminal again. In this way, the hot water device 100 makes it possible to supply hot water to the hot water terminal.

Next, the configuration of the sensible heat recovery heat exchanger (heat exchanger) 10 used in the water heating device 100 will be described with reference to FIGS. 2 to 4.

As shown in FIG. 2, the sensible heat recovery heat exchanger 10 of the present embodiment includes a case 11, a header 12, an endothermic pipe (heat transfer tubes: FIGS. 3 and 4) 13, and fins 16 (FIG. 4). ), A pressing member 17, and a fixing member 18.

The case 11 has a first side wall 11a, a second side wall 11b, a third side wall 11c, and a fourth side wall 11d. The first side wall 11a to the fourth side wall 11d are connected so as to form a square frame.

The first side wall 11a and the third side wall 11c face each other. The second side wall 11b and the fourth side wall 11d face each other. Each of the first side wall 11a to the fourth side wall 11d has a wall surface that separates the inside and the outside of the case 11.

The case 11 having the frame shape has openings at the top and bottom. As a result, the combustion gas can be supplied to the inside of the case 11 through the opening on the upper side of the case 11. Further, the combustion gas can be exhausted to the outside of the case 11 through the opening on the lower side of the case 11.

A header 12 is provided on the outer surface of the first side wall 11a. A joint 13a on the water inlet side and a joint 13b on the hot water outlet side are attached to the header 12 provided on the outer surface of the first side wall 11a. A header 12 (not shown) is also provided on the outer surface of the third side wall 11c.

As shown in FIG. 3, the header 12 provided on the outer surface of the first side wall 11a and the header 12 provided on the outer surface of the third side wall 11c are connected by a plurality of endothermic pipes 13. The plurality of heat absorbing pipes 13 have a heat absorbing pipe 13 located inside the case 11 and a heat absorbing pipe 13 located outside the case 11.

The flow of hot water flowing through the header 12 and the endothermic pipe 13 is as follows, for example.

The hot water that has entered from the joint 13a on the water entry side enters the endothermic pipe 13 located inside the case 11 through the header 12 provided on the most one end side of the outer surface of the first side wall 11a. The hot water that has entered the heat absorbing pipe 13 reaches a header 12 (not shown) provided on the outer surface of the third side wall 11c. The hot water that has reached the header 12 provided on the outer surface of the third side wall 11c reaches the header 12 provided on the outer surface of the first side wall 11a through another endothermic pipe 13 connected to the header 12.

In this way, the hot water is turned back from the third side wall 11c side to the first side wall 11a side after going from the first side wall 11a side to the third side wall 11c side. After that, the hot water flows so that the folding back to the third side wall 11c side and the folding back to the first side wall 11a side are repeated.

As shown in FIG. 2, the hot water that has reached the header 12 provided on the outermost end side of the outer surface of the first side wall 11a as described above passes through the heat absorbing pipe 13 provided on the outer surface of the second side wall 11b. 3 Reach the header 12 provided on the outer surface of the side wall 11c.

As shown in FIG. 3, the hot water that has reached the header 12 provided on the outer surface of the third side wall 11c is provided on the outer surface of the first side wall 11a through the heat absorbing pipe 13 provided on the outer surface of the fourth side wall 11d. The header 12 is reached, and finally, hot water is discharged from the joint 13b on the hot water side.

As shown in FIG. 4, a plurality of fins 16 are connected to the outer peripheral surface of the heat absorbing pipe 13 located inside the case 11. In FIG. 3, the fins are not shown for the sake of brevity.

The second side wall 11b is provided with a recess 11ba recessed from the outside to the inside of the case 11. At least a part of the endothermic pipe 13 outside the case 11 and located on the side of the second side wall 11b is fitted in the recess 11ba.

Further, the fourth side wall 11d is provided with a recess 11da recessed from the outside to the inside of the case 11. At least a part of the endothermic pipe 13 outside the case 11 and located on the side of the fourth side wall 11d is fitted in the recess 11da.

As shown in FIGS. 3 and 4, the spark plug 14 is attached to the wall surface of the case 11 so as to be located from the inside to the outside of the case 11. The spark plug 14 is attached to the second side wall 11b so as to penetrate the second side wall 11b, for example.

The spark plug 14 is arranged directly below the endothermic pipe 13 (the uppermost endothermic pipe 13) located outside the case 11 and closest to the burner 30 among the plurality of endothermic pipes 13 located on the second side wall 11b side. ing.

The spark plug 14 includes at least two electrodes. In other words, the spark plug 14 includes two or more electrodes. In this embodiment, the spark plug 14 includes, for example, a pair of spark plug electrodes 14a and a frame rod electrode 14b. The pair of spark plug electrodes 14a generate a flame in the mixed gas ejected from the burner 30 by generating an ignition spark. The frame rod electrode 14b applies an AC voltage between the flames generated by the burner 30 and utilizes the conductivity and rectifying action of the ionization of the flame to detect the direct current flowing from the frame rod electrode 14b to the flame to generate a flame. It is for detecting the presence or absence of. The spark plug electrode 14a and the frame rod electrode 14b may be one each. Further, it is not necessary to use only a pair of spark plug electrodes 14a and not the frame rod electrode 14b.

The spark plug 14 includes an insulator portion 14c. The insulator portion 14c is attached to the wall surface of the case 11. In the present embodiment, each of the pair of spark plug electrodes 14a and the frame rod electrode 14b penetrates the insulator portion 14c and is held by the insulator portion 14c. Each of the pair of spark plug electrodes 14a and frame rod electrodes 14b penetrates the insulator portion 14c and extends from the inside to the outside of the case 11. The pair of spark plug electrodes 14a and the frame rod electrodes 14b are arranged so as to be spaced apart from each other in the lateral direction (direction orthogonal to the vertical direction). The pair of spark plug electrodes 14a and the frame rod electrodes 14b are arranged so as to be aligned in the lateral direction, for example. Each of the pair of spark plug electrodes 14a and the frame rod electrode 14b is made of a conductive material such as metal. The insulator portion 14c is made of an insulating material such as ceramic.

The insulator portion 14c has a main body portion 14ca and a flange portion 14cc. The main body 14ca holds a pair of spark plug electrodes 14a and a frame rod electrode 14b, respectively. The flange portion 14cc projects outward from the outer peripheral surface of the main body portion 14ca. The insulator portion 14c is formed in an oval shape when viewed from the front.

The second side wall 11b is provided with a through hole (not shown). The insulator portion 14c is inserted into the through hole of the second side wall 11b. In this inserted state, the tips of the pair of spark plug electrodes 14a and the frame rod electrodes 14b are located inside the case 11.

In the above-mentioned inserted state, one end of the main body 14ca of the insulator 14c is located inside the case 11. The other end of the main body 14ca is located outside the case 11.

In the above-mentioned inserted state, the flange portion 14cc is located outside the case 11. The flange portion 14cc has a dimension larger than the opening dimension of the through hole of the second side wall 11b.

As shown in FIGS. 2 and 6, the pressing member 17 presses the flange portion 14cc from the side opposite to the second side wall 11b. The pressing member 17 is fixed to the second side wall 11b by the fixing member 18 in a state where the pressing member 17 presses the flange portion 14cc.

The fixing member 18 may be a screwing member such as a screw, a screw, or a bolt, or may be a pin or the like. The fixing member 18 penetrates the second side wall 11b, and the tip of the fixing member 18 is located inside the case 11.

As described above, the pressing member 17 is fixed to the second side wall 11b from the outside of the case 11 by the fixing member 18. As a result, the spark plug 14 can be firmly fixed to the case 11. As shown in FIG. 6, the packing 19 (FIG. 6) is sandwiched between the pressing member 17 and the second side wall 11b. The packing 19 prevents the combustion gas from leaking from the inside of the case 11 to the outside of the case 11. The fixing member 18 may penetrate the packing 19.

Next, the spark plug 14 will be described in more detail with reference to FIGS. 5 to 10.
As shown in FIGS. 5 and 6, the main body portion 14ca of the insulator portion 14c in the spark plug 14 has a base end portion 14ca1 and a tip end portion 14ca2. The base end portion 14ca1 is attached to the wall surface of the case 11. Specifically, the base end portion 14ca1 is attached to the wall surface of the second side wall 11b. In the above-mentioned inserted state, the base end portion 14ca1 is inserted into the through hole of the second side wall 11b.

The tip portion 14ca2 projects from the base end portion 14ca1 to the side opposite to the wall surface of the case 11. In the present embodiment, the tip portion 14ca2 projects both inside and outside the case 11. That is, the main body portion 14ca of the insulator portion 14c has a first tip portion 14ca2 projecting inside the case 11 and a second tip portion 14ca2 projecting outside the case 11. The tip portion 14ca2 may project to at least one of the inside and the outside of the case 11.

As shown in FIGS. 6 to 8, in the present embodiment, each of the first tip portion 14ca2 protruding inside the case 11 and the second tip portion 14ca2 protruding outside the case 11 has a tip. It has a surface TS and a groove DP. The tip surface TS is arranged on the side opposite to the base end portion 14ca1. The groove portion DP is configured to be recessed from the front end surface TS toward the base end portion 14ca1. The groove DP is arranged between each of the pair of spark plug electrodes 14a and the frame rod electrode 14b. Each portion of the insulator portion in which each of the pair of spark plug electrodes 14a and the frame rod electrode 14b is held is arranged laterally spaced apart from each other on the tip surface TS.

As shown in FIGS. 9 and 10, the groove DP is provided from the upper end TE to the lower end BE of the tip portion 14ca2. That is, the groove DP is provided so as to penetrate from the upper end TE to the lower end BE of the tip portion 14ca2.

The width of the groove DP in the lateral direction is narrowed from the upper end TE of the tip portion 14ca2 toward the lower end BE. The groove DP need only have a portion narrowing from the upper end TE to the lower end BE, and the lower end BE does not have to be the narrowest. In the present embodiment, the width of the groove DP is narrowed from the upper end TE of the tip portion 14ca2 to between the upper end TE and the lower end BE. The groove DP may be continuously narrowed from the upper end TE to the lower end BE of the tip portion 14ca2.

The groove portion DP has an inclined wall portion DPa and a straight wall portion DPb. The inclined wall portion DPa is provided at the upper end TE of the tip portion 14ca2. The inclined wall portion DPa has a downward slope in which the height decreases in a plane from the upper end TE of the tip portion 14ca2 toward the lower end BE. The inclined wall portion DPa is configured to surround the entire circumference of the groove portion DP in a plan view. The inclined wall portion DPa is located above each of the pair of spark plug electrodes 14a and frame rod electrodes 14b.

The straight wall portion DPb is connected to the lower end of the inclined wall portion DPa. The straight wall portion DPb is configured to extend straight in the vertical direction. The width of the straight wall portion DPb in the lateral direction is constant. The groove DP does not have to have a straight wall DPb.

The tip portion 14ca2 has one end EP1 arranged on one side of the groove DP and the other end EP2 arranged on the other side of the groove DP in the lateral direction. One end EP1 has a downward slope with a lower height on the opposite side of the other end EP2. The other end EP2 has a downward slope with a lower height on the opposite side of the one end EP1. The upper end TE of each of the one end EP1 and the other end EP2 has a curved surface shape in which the height decreases outward in the lateral direction. Specifically, the upper end TE of each of the one end EP1 and the other end EP2 has an arc shape.

As shown in FIG. 6, the width of the groove DP is widened from the base end portion 14ca1 toward the tip end surface TS. That is, in a plan view, the groove portion DP is open on the tip surface TS side, and the distance between the walls of the groove portion DP facing each other is widened on the tip surface TS side.

As shown in FIGS. 3 and 6, in the present embodiment, the tip portion 14ca2 projects from the base end portion 14ca1 into the case 11. The groove DP is arranged inside the case 11. Further, as shown in FIGS. 2 and 6, the tip portion 14ca2 projects from the base end portion 14ca1 to the outside of the case 11. The groove DP is arranged outside the case 11.

That is, as shown in FIGS. 2, 3 and 6, in the present embodiment, the tip portion 14ca2 projects from the base end portion 14ca1 both inside and outside the case 11. Groove DPs are arranged both inside and outside the case 11. The depth of the groove DP arranged inside the case 11 is larger than the depth of the groove DP arranged outside the case 11.

Next, the action and effect of the present embodiment will be described in comparison with a comparative example.
As shown in FIG. 11, in the comparative example, the width of the groove DP is constant from the upper end TE to the lower end BE of the tip portion 14ca2. That is, the width of the groove DP is not narrowed from the upper end TE of the tip 14ca2 toward the lower end BE. Therefore, the condensed water adhering to the upper end TE of the tip portion 14ca2 does not easily flow into the groove portion DP. Therefore, the condensed water collected in the upper end TE of the tip portion 14ca2 connects the two electrodes of the pair of spark plug electrodes 14a and the frame rod electrode 14b to each other, so that the two electrodes are easily conducted to conduct with each other.

On the other hand, according to the present embodiment, as shown in FIG. 12, the groove portion DP is recessed from the front end surface TS toward the base end portion 14ca1, and the pair of spark plug electrodes 14a and the frame rod electrode 14b. It is arranged between each, and is provided from the upper end TE to the lower end BE of the tip portion 14ca2. The width of the groove DP in the lateral direction is narrowed from the upper end TE of the tip portion 14ca2 toward the lower end BE. As a result, the dew condensation water generated on the wall surface of the second side wall 11b and dropped and adhered to the insulator portion 14c easily flows into the groove portion DP. Therefore, it is possible to prevent the two electrodes from conducting each other by connecting the two electrodes of the pair of spark plug electrodes 14a and the frame rod electrode 14b to each other by the condensed water accumulated in the upper end TE of the tip portion 14ca2. Therefore, it is possible to prevent the occurrence of poor insulation between the two electrodes.

As shown in FIG. 6, the width of the groove DP is widened from the base end portion 14ca1 toward the tip end surface TS. As a result, the dew condensation water is less likely to collect from the base end portion 14ca1 toward the tip surface TS at the upper end TE of the tip portion 14ca2, so that the dew condensation water collected at the upper end TE of the tip portion 14ca2 is paired with the spark plug electrode 14a and the frame. By connecting two of the rod electrodes 14b to each other, it is possible to further suppress the two electrodes from conducting each other.

As shown in FIG. 12, one end EP1 of the tip 14ca2 has a downward slope with a lower height on the opposite side of the other end EP2, and the other end EP2 has one end. On the opposite side of EP1, there is a downward slope with a lower height. As a result, the dew condensation water adhering to the one end EP1 can be flowed to the side opposite to the other end EP2, and the dew condensation water adhering to the other end EP2 can be flowed to the side opposite to the one end EP1. .. Therefore, the condensed water is less likely to collect in the upper end TE of the tip portion 14ca2. Therefore, the condensed water collected in the upper end TE of the tip portion 14ca2 further suppresses the two electrodes from conducting each other by connecting the two electrodes of the pair of spark plug electrodes 14a and the frame rod electrode 14b to each other. be able to.

As shown in FIG. 12, the inclined wall portion DPa has a downward slope whose height decreases in a plane from the upper end TE to the lower end BE of the tip portion 14ca2. As a result, the dew condensation water can easily flow through the groove portion DP by flowing the dew condensation water along the downward slope in which the height becomes low in the plane of the inclined wall portion DPa.

As shown in FIGS. 3 and 6, the tip portion 14ca2 projects from the base end portion 14ca1 to the inside of the case 11, and the groove portion DP is arranged inside the case 11. As a result, the condensed water collected in the upper end TE of the tip portion 14ca2 inside the case 11 connects the two electrodes of the pair of spark plug electrodes 14a and the frame rod electrode 14b to each other, so that the two electrodes are electrically connected to each other. Can be suppressed.

As shown in FIGS. 2 and 6, the tip portion 14ca2 projects from the base end portion 14ca1 to the outside of the case 11, and the groove portion DP is arranged outside the case 11. As a result, the condensed water collected at the upper end TE of the tip portion 14ca2 outside the case 11 connects the two electrodes of the pair of spark plug electrodes 14a and the frame rod electrode 14b to each other, so that the two electrodes are electrically connected to each other. Can be suppressed.

The amount of dew condensation water generated inside the case 11 is larger than that generated outside the case 11. Therefore, the depth of the groove DP arranged inside the case 11 is larger than the depth of the groove DP arranged outside the case 11, so that the dew condensation water generated inside the case 11 is collected from the groove DP. Can be flushed a lot. Therefore, it is possible to effectively prevent the two electrodes from conducting each other by connecting the two electrodes with the condensed water accumulated in the upper end TE of the tip portion 14ca2 inside the case 11 where a large amount of condensed water is generated. ..

Next, various modifications of the spark plug 14 will be described with reference to FIGS. 13 to 17. Unless otherwise specified, the configurations of the various modifications are the same as those of the present embodiment. Therefore, the same elements are designated by the same reference numerals and the description thereof will not be repeated.

As shown in FIG. 13, in the first modification of the spark plug 14, the inclined wall portion DPa of the groove portion DP of the spark plug 14 has a curved surface height from the upper end TE of the tip portion 14ca2 toward the lower end BE. Has a downhill slope. As a result, the dew condensation water can easily flow through the groove portion DP by flowing the dew condensation water along the downward slope in which the height becomes low in the curved surface shape of the inclined wall portion DPa.

As shown in FIG. 14, in the second modification of the spark plug 14, the inclined wall portion DPa of the groove portion DP of the spark plug 14 has a flat height from the upper end TE of the tip portion 14ca2 toward the lower end BE. Has a downhill slope. The inclined wall portion DPa is provided so as to be a tangent line of a virtual circle VC. The virtual circle VC surrounds each of the pair of spark plug electrodes 14a and the frame rod electrodes 14b in the circumferential direction of each electrode, and each electrode is located at the center. For this reason, by setting a virtual circle VC to ensure insulation, dew condensation water flows along a downward slope where the height is lowered in a plane of the inclined wall portion DPa while ensuring insulation. , Condensation water can easily flow through the groove.

As shown in FIGS. 15 to 17, in the third modification of the spark plug 14, the tip portion 14ca2 has at least two cylindrical portions CP. Specifically, the tip portion 14ca2 has three cylindrical portions CP. A pair of spark plug electrodes 14a and frame rod electrodes 14b are inserted into each of the three cylindrical portions CP in the axial direction of the cylindrical portion CP. The groove DP is arranged between two cylindrical CPs of the three cylindrical CPs. In the present embodiment, the cylindrical portion CP and the frame rod electrode into which the ignition plug electrodes 14a arranged in the center in the lateral direction are inserted between the two cylindrical portions CP through which the pair of spark plug electrodes 14a are inserted are inserted. A groove DP is arranged between the cylindrical CP and the cylindrical CP through which the 14b is inserted.

In the third modification of the spark plug 14, dew condensation water can flow through the groove DP arranged between the two cylindrical CPs. Further, each of the two electrodes inserted through the two cylindrical portions CP can uniformly secure the insulating property in the radial direction of the cylindrical portion CP.

Further, the tip portion 14ca2 has a connecting wall DPc arranged between the two cylindrical portion CPs out of the three cylindrical portion CPs. Each of the three cylindrical portions CP projects from the base end portion 14ca1 to the side opposite to the wall surface of the case 11 with respect to the connecting wall DPc. The thickness dimension of the connecting wall DPc is smaller than the thickness dimension of the cylindrical portion CP in the direction extending in the cylindrical portion CP of each of the pair of spark plug electrodes 14a and the frame rod electrode 14b. The upper end TE of the connecting wall DPc has a downward slope whose height is lowered from the base end portion 14ca1 to the side opposite to the wall surface of the case 11. As a result, by flowing the dew condensation water along the connection wall DPc, the dew condensation water can easily flow through the groove DP.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and it is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

10 Real heat recovery heat exchanger, 11 case, 11a 1st side wall, 11b 2nd side wall, 11c 3rd side wall, 11d 4th side wall, 12 header, 13 heat absorption pipe, 14 ignition plug, 14a ignition plug electrode, 14b frame rod Electrode, 14c porcelain part, 14ca body part, 14ca1 base end part, 14ca2 tip part, 14cc flange part, 16 fins, 17 holding member, 18 fixing member, 19 packing, 20 latent heat recovery heat exchanger, 30 burner, 31 chamber, 32 blower, 33 duct, 34 venturi, 35 orifice, 36 gas valve, 40 piping, 41 bypass piping, 42 three-way valve, 43 liquid-liquid heat exchanger, 44 hot water piping, 50 housing, 100 hot water device, BE lower end, CP Cylindrical part, DP groove part, DPa inclined wall part, DPb straight wall part, DPc connection wall, EP1 one end, EP2 other end, TE upper end, TS tip surface, VC virtual circle.

Claims (8)

A burner that generates combustion gas for heating,
A heat exchanger provided below the burner and heating hot water with the combustion gas.
With an ignition plug that ignites the burner,
The heat exchanger includes a case having a wall surface separating the inside and the outside.
The spark plugs are arranged with an insulator portion attached to the wall surface of the case, each of which penetrates the insulator portion, extends from the inside of the case to the outside, and is laterally spaced from each other. Including two electrodes
The insulator portion includes a base end portion attached to the wall surface of the case and a tip end portion protruding from the base end portion to the side opposite to the wall surface.
The tip portion has a tip surface arranged on the side opposite to the base end portion, and a groove portion recessed from the tip end surface toward the base end portion.
The groove portion is arranged between the two electrodes and is provided from the upper end to the lower end of the tip portion.
The width of the groove portion in the lateral direction is narrowed from the upper end to the lower end of the tip portion .
The groove includes an inclined wall portion provided at the upper end of the tip portion.
The inclined wall portion is a water heating device having a downward slope whose height is lowered in a plane from the upper end to the lower end of the tip portion. The water heating device according to claim 1, wherein the width of the groove portion is widened from the base end portion toward the tip end surface. The tip includes, in the lateral direction, one end arranged on one side of the groove and the other end arranged on the other side of the groove.
The one end has a downward slope with a lower height on the opposite side of the other end.
The water heating device according to claim 1 or 2, wherein the other end portion has a downward slope having a lower height on the side opposite to the one end portion. The inclined wall portion is provided so as to surround the electrode in the circumferential direction of the electrode and to be a tangent to a virtual circle in which the electrode is located at the center, according to any one of claims 1 to 3. The hot water device described. A burner that generates combustion gas for heating,
A heat exchanger provided below the burner and heating hot water with the combustion gas.
With an ignition plug that ignites the burner,
The heat exchanger includes a case having a wall surface separating the inside and the outside.
The spark plugs are arranged with an insulator portion attached to the wall surface of the case, each of which penetrates the insulator portion, extends from the inside of the case to the outside, and is laterally spaced from each other. Including two electrodes
The insulator portion includes a base end portion attached to the wall surface of the case and a tip end portion protruding from the base end portion to the side opposite to the wall surface.
The tip portion has a tip surface arranged on the side opposite to the base end portion, and a groove portion recessed from the tip end surface toward the base end portion.
The groove portion is arranged between the two electrodes and is provided from the upper end to the lower end of the tip portion.
The width of the groove portion in the lateral direction is narrowed from the upper end to the lower end of the tip portion.
The tip includes two cylinders.
Each of the two electrodes is inserted into each of the two cylindrical portions in the axial direction of the cylindrical portion.
The groove portion is arranged between the two cylindrical portions, and the groove portion is arranged between the two cylindrical portions.
The tip includes a connecting wall disposed between the two cylinders.
Each of the two cylindrical portions projects from the base end portion to the side opposite to the wall surface from the connecting wall.
The upper end of the connecting wall, the said wall from said proximal end height on the opposite side has a downwardly sloping lower, warm water device. The tip portion projects from the base end portion into the inside of the case.
The water heating device according to any one of claims 1 to 5 , wherein the groove is arranged inside the case. The tip portion projects from the base end portion to the outside of the case.
The water heating device according to any one of claims 1 to 5 , wherein the groove is arranged outside the case. The tip portion projects from the base end portion to both the inside and the outside of the case.
The grooves are arranged both inside and outside the case.
The hot water according to any one of claims 1 to 5 , wherein the depth of the groove arranged inside the case is larger than the depth of the groove arranged outside the case. apparatus.

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