JP2007100989A - Water heating appliance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce costs and to miniaturize an appliance as a whole by rationally discharging drain while saving a space. <P>SOLUTION: In this water heating appliance, a sub-heat exchanger 8 is composed of a pair of right and left headers 9, 9, and cylindrical heating tubes 10, 10 hung between the headers 9, 9 in parallel with each other at a prescribed interval in the horizontal direction. Each header 9 branches one flow channel into a plurality of flow channels, the branched flow channels are respectively composed of manifolds opened at faces opposite to each other, and their downstream sides are higher than upstream sides, thus the heating tubes 10 are inclined to lower one axial end side. A receiver trough 15 receiving only a lowermost portion of the header 9 without contact is disposed at a lower portion of the lowered header 9. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hot water device such as a water heater provided with two heat exchangers that recover sensible heat and latent heat from combustion exhaust gas of a burner to heat water flow.

  For example, in a water heater, a main heat exchanger mainly for the purpose of sensible heat recovery is provided upstream of the combustion exhaust passage of the burner, and a sub heat exchanger mainly for the purpose of latent heat recovery is provided on the downstream side. Some are intended to provide high thermal efficiency. The auxiliary heat exchanger is provided with a plurality of fins serving as heat absorbing portions orthogonal to the outer periphery of a heat transfer tube through which water passes at predetermined intervals along the heat transfer tube. In addition, a tray-shaped drain receiving portion that receives drain generated in the auxiliary heat exchanger is provided between the main heat exchanger and the auxiliary heat exchanger, and the generated acidic drain is neutralized to externally. (See, for example, Patent Document 1).

JP 2004-198065 A

Thus, by providing a separate drain receiving part below the auxiliary heat exchanger, the number of parts increases and the time and effort of assembly increase, and the entire instrument also increases in size. Therefore, in addition to incurring costs, even if an existing water heater is replaced with such a high efficiency type, it may not be installed due to the limitation of the installation space, which has been an obstacle to the spread of high efficiency type water heaters. .
Moreover, since the drain which has not fallen to a drain receiving part will be in the state adhering to a heat exchanger tube, the heat transfer effect | action in the adhesion part will be lost and it will lead to the fall of thermal efficiency.

  Therefore, the present invention rationally discharges the drain of the auxiliary heat exchanger with a simple and space-saving structure, so that the workability related to assembly is good, the overall apparatus can be kept compact, and is also high. An object of the present invention is to provide a hot water device capable of suitably maintaining thermal efficiency.

In order to achieve the above object, the invention according to claim 1 is characterized in that the auxiliary heat exchanger includes a pair of headers that branch one flow path into a plurality of openings and open the branch flow paths between opposing surfaces. The heat transfer tubes are connected between the openings of the headers, and each of the heat transfer tubes is provided with an inclination in which one side in the axial direction is lower than the other side.
In addition to the object of claim 1, the invention described in claim 2 connects both headers in an inclined state to both headers in order to improve the workability related to assembly. Can be maintained in a horizontal position.

According to the invention described in claim 1, due to the inclination of the heat transfer tube, it is possible to guide and discharge the drain to one place by the auxiliary heat exchanger alone, and it is necessary to provide a large tray that covers the lower side of the auxiliary heat exchanger. Disappear. Therefore, the number of parts is reduced and the workability related to the assembly is improved, and the cost can be reduced and the entire apparatus can be made compact.For example, the existing water heater can be easily replaced with a high efficiency type water heater. This will lead to the spread of high-efficiency water heaters.
Moreover, since the generated drain is quickly discharged from the auxiliary heat exchanger, a decrease in the heat transfer effect due to the adhesion of the drain to the heat transfer tube is effectively suppressed. Therefore, high thermal efficiency can be suitably maintained.
According to the second aspect of the invention, in addition to the effect of the first aspect, both headers can be maintained in a horizontal posture, so that workability related to assembly is improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Drawing 1 is a schematic structure figure which looked at a water heater which is an example of warm water equipment from the side, and the left side becomes the front. The water heater 1 includes a combustion chamber 3 having an air supply fan 4 at the lower side and an exhaust port 5 at the front upper side in the appliance main body 2, and a rear lower portion of the combustion chamber 3 in the combustion chamber 3. The burner 6, 6... Combusts the mixed gas of the fuel gas and the primary air from the air supply fan 4, and the sensible heat in the combustion exhaust from the burner 6 above the burner 6. A main heat exchanger 7 to be recovered and a sub heat exchanger 8 which is provided in front of the combustion chamber 3 and mainly recovers latent heat are provided. The first guide plate 3a is provided between the main heat exchanger 7 and the sub heat exchanger 8 and is inclined upward as it goes rearward to guide the sneaking of the combustion exhaust to the front. 5 is a second guide plate that hangs down from the upper wall of the combustion chamber 3 between the auxiliary heat exchanger 8 and the auxiliary heat exchanger 8 and guides passage of combustion exhaust gas through the auxiliary heat exchanger 8.

FIG. 2 is an explanatory view of the combustion chamber portion including the auxiliary heat exchanger 8 as viewed from the front. The auxiliary heat exchanger 8 includes a pair of left and right headers 9 and 9, and a vertical and horizontal direction between the headers 9 and 9. The cylindrical heat transfer tubes 10, 10... Are installed so as to be parallel to each other at a predetermined interval. As for each heat exchanger tube 10, the heat exchanger tubes 10 and 10 of the row | line | column adjacent in the up-down and left-right direction are arranged in a staggered manner. Each header 9 is formed by a manifold that branches one flow passage 11 into a plurality of openings and opens the branch flow passages 12, 12... On opposite surfaces, and has fins between the opposed openings 13 and 13. The non-cylindrical heat transfer tubes 10, 10,... Are connected with a known structure in which the end portions are inserted and sealed with a sealing member such as an O-ring.
Therefore, the water supplied from the flow path 11 of one header 9 branches and flows to each heat transfer tube 10 and is collected in the flow path 11 of the other header 9 and discharged. Here, a water supply pipe (not shown) led into the appliance is connected to the left header 9 in FIG. 2, the auxiliary heat exchanger 8 is arranged upstream of the main heat exchanger 7, and the right header 9 is connected to the main header by piping. Connected to the water inlet side of the heat exchanger 7, a hot water pipe (not shown) is connected to the water outlet side of the main heat exchanger 7.

The auxiliary heat exchanger 8 is inclined such that the header 9 on the downstream side (right side) is higher than the header 9 on the upstream side (left side in FIG. 2), and one side in the axial direction of each heat transfer tube 10 is lowered. Are equally granted. The inclination angle of the heat transfer tube 10 with respect to the horizontal plane is desirably set to 30 ° or less because the dimension in the vertical direction increases if it is too large.
Further, as shown in FIG. 1, a receiving rod 15 that receives only the lowermost portion of the header 9 in a non-contact manner is provided below the lower left header 9. This receptacle 15 is connected to a drain discharge pipe 16 provided with a neutralizer 17.

  On the other hand, a controller (not shown) is provided in the appliance, and when water is passed into the appliance, the ignition control of the burner 6 is performed, and the well-known hot water temperature is made to coincide with the set temperature set by a remote controller or the like. Perform temperature control. The controller also controls the ratio between the gas amount and the air amount by changing the rotational speed of the air supply fan 4 in accordance with the change in the gas amount accompanying the hot water temperature control.

  In the water heater 1 configured as described above, due to the combustion of the burner 6, the combustion exhaust gas first passes through the main heat exchanger 7, and sensible heat is recovered by heat exchange with the heat transfer tubes to be passed. After that, ascending in the combustion chamber 3, as shown by the arrow in FIG. 1, it goes around the first guide plate 3a and reaches the auxiliary heat exchanger 8, and moves downward while being guided by the second guide plate 3b. After passing between the heat transfer tubes 10, 10, it goes up around the lower end of the second guide plate 3 b and is discharged from the exhaust port 5. Therefore, in the auxiliary heat exchanger 8, sensible heat that has not been recovered by the main heat exchanger 7 is recovered by heat exchange with the heat transfer tube 10. And when the temperature of combustion exhaust gas becomes below a dew point, drain will generate | occur | produce and it will also be possible to collect | recover latent heat. The generated drain flows to the left side along the surface of the heat transfer tube 10 due to the inclination of the heat transfer tube 10, gathers on the surface of the header 9, and falls on the receiving rod 15 from the lowermost part of the header 9. Then, it neutralizes with the neutralizer 17, and is discharged | emitted to the sewer etc. outside an instrument.

Thus, according to the hot water heater 1 of the said form, a pair of header 9 which makes the sub heat exchanger 8 branch the one flow path 11 into plurality, and opens the branched flow path 12 between mutually opposing surfaces, 9 and a plurality of cylindrical heat transfer tubes 10 connected between the respective openings 13 of the headers 9 and 9, and each of the heat transfer tubes 10 is provided with an inclination in which one side in the axial direction is lowered. The sub heat exchanger 8 alone can guide the drain to one place and discharge it, and there is no need to provide a large tray that covers the lower side of the sub heat exchanger 8. Therefore, the number of parts is reduced and the workability related to the assembly is improved, and the cost can be reduced and the entire apparatus can be made compact.For example, the existing water heater can be easily replaced with a high efficiency type water heater. This will lead to the spread of high-efficiency water heaters.
Further, since the generated drain is quickly discharged from the auxiliary heat exchanger 8, a decrease in heat transfer effect due to the adhesion of drain to the heat transfer tube 10 is effectively suppressed. Therefore, high thermal efficiency can be suitably maintained.

In addition, the structure of a sub heat exchanger is not restricted to the said form, For example, it does not interfere as a structure which arranges a some heat exchanger tube in parallel in a horizontal direction. Of course, it may be installed not above the combustion chamber but above the main heat exchanger.
A structure as shown in FIG. 3 is also conceivable. In this sub heat exchanger 8a, the heat transfer tubes 10 are arranged in a plurality of rows in an inclined state in the horizontal and vertical directions between the headers 18 and 18. Here, the opposing surfaces of the headers 18 and 18 are arranged on each other. Each of the horizontal rows of the heat transfer tubes 10 is formed in a saw blade shape so as to be flat portions 19 and 19 substantially orthogonal to the heat transfer tubes 10. In this way, by connecting the heat transfer tubes 10 to the header 18 in an inclined state, the headers 18 and 18 can be maintained in a horizontal posture without being inclined. Connection of piping becomes easy, and workability related to assembly is improved.
Further, as in the auxiliary heat exchanger 8b shown in FIG. 4, the entire opposing surfaces of the headers 20 and 20 may be inclined to connect the heat transfer tubes 10, 10,... You may make it connect a heat pipe diagonally with respect to the perpendicular | vertical opposing surface of a header.

Furthermore, the header is not limited to a block shape, and a structure in which an opening or a branch pipe is connected to the side of a pipe that forms a single flow path to form a branch flow path can also be employed. In this case, the horizontal posture of the header can be maintained by connecting the heat transfer tube directly to the opening in an inclined state or by connecting the heat transfer tube to a branch tube that has been inclined in advance. Of course, the number of heat transfer tubes, the number of arrays, and the like can be changed as appropriate.
In addition, the present invention can be applied not only to the water heater but also to other devices such as a floor heater and a bath device as long as it is a hot water device having an auxiliary heat exchanger that recovers latent heat.

It is the schematic block diagram which looked at the water heater from the side. It is explanatory drawing which looked at the combustion chamber part containing a subheat exchanger from the front. It is front explanatory drawing which shows the example of a change of a header. It is front explanatory drawing which shows the example of a change of a header.

Explanation of symbols

1 .. Hot water heater, 2 .... Appliance body, 3 .... Combustion chamber, 4 .... Air supply fan, 6 .... Burner, 7 .... Main heat exchanger, 8, 8a, 8b ..., Sub heat exchanger, 9, 18, 20 ... header 10, 10 ... heat transfer tube, 11 ... flow path, 12 ... branch flow path.

Claims (2)

A main heat exchanger that recovers sensible heat from the combustion exhaust of the burner and heats the water flow in the heat transfer tube, and a latent heat is recovered from the combustion exhaust that has passed through the main heat exchanger to recover the heat in the heat transfer tube. A hot water device provided with a sub heat exchanger for heating water flow,
The auxiliary heat exchanger is formed by a pair of headers that branch a flow path into a plurality of openings and open the branched flow paths between opposing surfaces, and heat transfer tubes connected between the openings of both headers. And the hot water apparatus characterized by providing the said heat exchanger tube with the inclination which the one side of an axial direction becomes low with respect to the other side. The hot water apparatus according to claim 1, wherein the headers can be maintained in a horizontal posture by connecting the heat transfer tubes in an inclined state to the headers.

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