JP2014240732A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger that prevents generation of drain within radiator tubes, has high installation performance and also prevents noise during operation while requiring enhancement of thermal efficiency.SOLUTION: A heat exchanger 12 for releasing heat of combustion gas sent from a combustion part 11 and heating air introduced into a ventilation passage 100 includes: a plurality of radiator tubes 120 extending within the ventilation passage 100 in a direction intersecting with the flowing direction of the air and juxtaposed in the flowing direction; and spiral plate-shaped inner fins 121 each arranged over the approximately whole length within each of the radiator tubes 120 and converting a flow of the combustion gas sent into each of the radiator tubes 120 into turbulence. Shapes of the inner fins 121 are made to differ between the radiator tubes 120 located on the upstream side and the radiator tubes 120 located on the downstream side out of the radiator tubes 120 juxtaposed in the flowing direction, so that a degree of heat radiation of the radiator tubes 120 located on the upstream side is made smaller than that of the radiator tubes 120 located on the downstream side.

Description

  The present invention relates to a heat exchanger, and more particularly to a heat exchanger provided with an inner fin for making the flow of combustion gas sent into a heat radiating pipe turbulent.

  Air for combustion of gas is taken into the combustion section from the outside through the air supply / exhaust pipe, while the combustion gas generated in the combustion section is sent into a heat exchanger composed of a plurality of heat radiating pipes, and indoor air introduced into the main body There is known a so-called gas FF type heater that heats and heats the air through an air supply / exhaust pipe. However, in a heat exchanger incorporated in this type of heater, in order to increase heat efficiency, heat dissipation is performed. Some pipes are provided with inner fins for turbulent combustion gas flow.

  However, in the case of such a heat exchanger, the heat radiating pipe located on the upstream side of the ventilation path heats and heats indoor air that is colder than the heat radiating pipe on the downstream side. Therefore, if the same inner fin is provided for all of the heat radiating pipes and the turbulent flow in each of the heat radiating pipes is strengthened uniformly, the degree of heat radiation of the heat radiating pipe located upstream becomes larger, Depending on the amount of combustion, the combustion gas flowing in the upstream side heat radiating pipe becomes below the dew point. As a result, there is a possibility that drain is generated inside the heat radiating tube and the deterioration of the heat exchanger is promoted.

  Therefore, in this type of conventional heat exchanger, an inner fin shorter than other heat radiating pipes is inserted in the heat radiating pipe on the upstream side to reduce the turbulence in a part of the area of the heat radiating pipe, thereby reducing the degree of heat dissipation. Has been proposed in which the generation of drain inside the heat radiating tube is suppressed (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 58-42833

  However, in the above-described conventional heat exchanger, since the short inner fin is supported in a cantilevered manner at one end side in the heat radiating pipe in the heat radiating pipe in which the short inner fin is inserted, the heat radiating pipe enters the heat radiating pipe during operation. It is difficult to fix the short inner fin so as not to vibrate due to a sudden change in the flow pressure of the combustion gas to be sent, and the assembly is not easy. Moreover, in this thing, in the upstream heat radiation pipe | tube in which the short inner fin was inserted, the heat radiation degree differs notably in the location in which the inner fin is arrange | positioned, and the location in which it is not arrange | positioned. For this reason, the cold indoor air introduced into the ventilation passage of the main body reaches the downstream side without sufficient heat exchange at the location where the inner fins are not disposed, and the combustion gas is dew point inside the downstream radiating pipe. There was a possibility that drainage would be caused at a temperature lower than that. In addition, since the difference in thermal expansion between the location where the inner fin is disposed and the location where the inner fin is not disposed is larger than the above-described difference in the degree of heat dissipation, a squeak noise is generated when the heat radiation tube is thermally expanded during operation. Noise may occur.

  The present invention has been made in view of the above circumstances, and the purpose thereof is a heat exchanger that is required to have high thermal efficiency. An object of the present invention is to provide a heat exchanger that hardly generates noise.

  The present invention is a heat exchanger that releases heat of combustion gas fed from a combustion section and heats air introduced into the air passage, and extends in a direction intersecting the air flow direction in the air passage. And a plurality of heat radiating pipes arranged in parallel in the flow direction, and a spiral plate-like inner fin that is provided over substantially the entire length of each radiating pipe and turbulently flows the combustion gas fed into the radiating pipe. A plurality of heat radiating pipes arranged in the flow direction, and the heat radiating pipe located on the upstream side and the heat radiating pipe located on the upstream side so that the heat radiating degree of the heat radiating pipe located on the upstream side is smaller than that of the heat radiating pipe located on the downstream side The shape of the inner fin is different from that of the located heat radiating pipe.

  In this case, among the radiating pipes arranged in the flow direction in the air passage, the radiating pipe on the upstream side is arranged so that the radiating degree of the radiating pipe located on the upstream side is smaller than the radiating degree of the radiating pipe located on the downstream side. Since the shape of the inner fin is made different between the heat radiating pipe and the downstream side heat radiating pipe, the combustion gas in the heat radiating pipe located on the upstream side of the air passage is unlikely to be below the dew point. Therefore, the generation of drain inside the heat radiating tube can be sufficiently suppressed. In particular, in this case, since the inner fin extends over substantially the entire length in the heat radiating tube, the heat radiation degree in each heat radiating tube becomes uniform as a whole. Therefore, even if cold indoor air is introduced into the air passage during operation, the heat is sufficiently exchanged by the upstream side heat radiating pipe and led to the downstream side. Therefore, it is difficult for the combustion gas to fall below the dew point temperature inside the downstream heat radiating pipe, and the generation of drain inside the heat radiating pipe can be more reliably prevented. In addition, by extending the inner fins over almost the entire length of each radiating tube, the inner fins are securely supported at both ends of the radiating tube so that they do not vibrate due to changes in the flow pressure of the combustion gas sent into the radiating tube during operation. It can be fixed and assembled easily. In addition, the variation in the thermal expansion of the entire heat radiating tube is reduced, and noise such as a squeak noise caused by the variation in the thermal expansion is hardly generated.

  In the heat exchanger, it is desirable that the twist pitch of the inner fins of the heat radiating pipe located on the upstream side is larger than the twist pitch of the inner fins of the heat radiating pipe located on the downstream side.

  In this product, the heat release degree of each heat radiation pipe is changed by changing the torsion pitch of the inner fin between the heat radiation pipe on the upstream side and the heat radiation pipe on the downstream side. And vibration of the inner fin can be suppressed.

  As described above, according to the present invention, in a heat exchanger that requires high thermal efficiency, a heat exchanger that is less likely to generate drainage inside the heat radiating pipe, has high ease of assembly, and does not easily generate noise during operation. Can be provided.

Drawing 1 is a schematic structure figure of a heater provided with a heat exchanger concerning an embodiment of the invention. FIG. 2 is a schematic longitudinal sectional view of the heat exchanger according to the embodiment of the present invention. FIG. 3 is a schematic longitudinal sectional view of a heat exchanger according to another embodiment (1) of the present invention. FIG. 4 is a schematic longitudinal sectional view of a heat exchanger according to another embodiment (2) of the present invention. FIG. 5 is a schematic longitudinal sectional view of a heat exchanger according to another embodiment (3) of the present invention.

  Next, the heat exchanger according to the embodiment of the present invention will be specifically described with reference to the accompanying drawings.

  In FIG. 1, gas combustion air is taken into the combustion section 11 from the outdoor S <b> 1 through the air supply pipe 21, while the combustion gas generated in the combustion section 11 is sent into the heat exchanger 12 including a plurality of heat radiation pipes 120. The gas FF type heater 1 is configured to heat the indoor air introduced into the casing 10 through heat exchange and then discharge it to the outdoor S1 through the exhaust pipe 22. Although not shown, a burner for burning the gas sent from the gas pipe 23 is incorporated in the combustion unit 11, and the combustion gas generated by this burner is introduced into the heat exchanger 12.

  An air passage 100 serving as an air passage for the room S2 is formed in the casing 10 of the heater 1. By operating the circulation fan 13 incorporated in the air passage 100, the air in the room S2 is supplied. The air is introduced into the air passage 100 from the air supply port 101 at the upper back of the casing 10, and is led to the room S <b> 2 from the air outlet 102 at the lower front of the casing 10 through the arrangement part of the heat exchanger 12.

  The heat exchanger 12 according to the embodiment of the present invention is composed of a plurality of heat radiating tubes 120 arranged in a staggered manner in a cross-sectional view, and the combustion gas discharged from the combustion unit 11 is the heat radiating tubes. Through the inflow header 14 connected to one end of 120, the heat is introduced into each heat radiating pipe 120 at once. Then, the heat in the combustion gas is released into the air in the ventilation path 100 through the surface of each heat radiating pipe 120.

  As shown in FIG. 2, the heat radiating pipe 120 is formed of a single straight metal pipe having corrosion resistance, such as stainless steel, in a direction intersecting with the flow direction of room air introduced into the air passage 100. A plurality of lines are arranged in the flow direction. Note that the number, arrangement, and length of the heat radiating pipes 120 are appropriately set in consideration of the amount of combustion gas introduced into the heat radiating pipe 120 and the heating capacity of the heater 1.

  One end of the heat radiating pipe 120 is brazed and joined to the inflow header 14 fixed to the side wall of the ventilation path 100. On the other hand, the other end of the heat radiating pipe 120 is brazed and joined to the outflow header 15 fixed to the side wall of the ventilation path 100.

  Inner fins 121 are inserted in the internal space of the heat radiating pipe 120 to make the flow of the combustion gas sent from the combustion section 11 into the heat radiating pipe 120 through the inflow header 14 into the turbulent flow and lead out to the outflow header 15 side. Yes.

  The inner fin 121 is a spiral metal plate formed by twisting a plurality of long metal plates having corrosion resistance, such as stainless steel, a plurality of times. Is provided. The inner fin 121 may be formed using a material other than metal as long as it has heat resistance and corrosion resistance.

  Both end portions of the inner fin 121 are fixed by brazing to both end portions of the heat radiating tube 120. Further, the peripheral end surface of the inner fin 121 (the end surface spirally formed along the inner peripheral surface of the heat radiating tube 120) is in contact with the inner peripheral surface of the heat radiating tube 120 over substantially the entire length thereof. Therefore, the combustion gas introduced into the heat radiating pipe 120 flows spirally along the curved surface of the inner fin 121 and becomes a turbulent flow. As a result, the degree of heat dissipation is greater than that of the configuration in which the inner fin 121 is not disposed in the heat radiating pipe 120. In this embodiment, the inner fin 121 is fixed to the heat radiating pipe 120 by brazing, but a fixing member may be attached to both ends, and the inner fin 121 may be fixed to the peripheral end surface of the inner fin 121 and the heat dissipation. You may fix by the contact frictional force with the internal peripheral surface of the pipe | tube 120. FIG.

  The twist pitch P of the inner fins 121 is that of the heat radiating pipe 120 located on the upstream side (the upper side in FIG. 2) of the heat radiating pipes 120 arranged in the flow direction of the room air in the air passage 100 (the vertical direction in FIG. 2). Is set to be larger than the heat radiating pipe 120 located on the downstream side (lower side in FIG. 2). That is, the inner fin 121 is formed by the upstream side heat radiating pipe 120 and the downstream side heat radiating pipe 120 so that the heat radiating degree of the heat radiating pipe 120 located on the upstream side is smaller than the heat radiating degree of the heat radiating pipe 120 located on the downstream side. Different shapes. Thereby, the combustion gas which flows through the inside of the heat radiating pipe 120 on the upstream side is unlikely to be below the dew point. Therefore, it is difficult for drainage to be generated inside the heat radiating tube 120. Further, since the degree of heat radiation of the downstream side heat radiating pipe 120 is set larger than that of the upstream side heat radiating pipe 120, it is possible to increase the heat efficiency of the heat exchanger 12.

  Thus, according to the above-described embodiment, among the heat radiating pipes 120 arranged in the flow direction in the air passage 100, the heat radiating degree of the heat radiating pipe 120 located on the downstream side is the heat radiation of the heat radiating pipe 120 located on the downstream side. Since the shape of the inner fin 121 is different between the upstream side heat radiating pipe 120 and the downstream side heat radiating pipe 120 so as to be smaller than the degree, the combustion gas in the heat radiating pipe 120 located on the upstream side of the air passage 100 is Less likely to be below dew point temperature. Therefore, the generation of drain in the heat radiating tube 120 can be sufficiently suppressed. In particular, in this case, since the inner fin 121 extends over substantially the entire length in the heat radiating tube 120, the heat radiation degree in each heat radiating tube 120 becomes uniform as a whole. Therefore, even if cold indoor air is introduced into the air passage 100 during operation, the heat is sufficiently exchanged by the upstream side heat radiating pipe 120 and led to the downstream side. Therefore, the combustion gas is unlikely to become the dew point temperature or lower in the downstream side heat radiating pipe 120, and the generation of drain in the heat radiating pipe 120 can be prevented more reliably. Further, by extending the inner fin 121 over substantially the entire length of each heat radiating pipe 120, the inner fin 121 is radiated so as not to vibrate due to a change in the flow pressure of the combustion gas introduced into the heat radiating pipe 120 during operation. It can be securely fixed at both ends of 120 and can be easily assembled. In addition, the variation in the thermal expansion of the entire heat radiating tube 120 is reduced, and noise such as a squeak noise caused by the variation in the thermal expansion hardly occurs. Therefore, in a heat exchanger that requires high thermal efficiency, it is possible to provide a heat exchanger that is unlikely to generate drain in the heat radiating pipe 120, has high ease of assembly, and is unlikely to generate noise during operation.

  Further, in this case, by changing the twist pitch P of the inner fin 121 between the upstream side heat radiating pipe 120 and the downstream side heat radiating pipe 120, the heat radiating degree for each of the heat radiating pipes 120 is made different. The generation of drain and the vibration of the inner fin 121 can be suppressed with a simple structure.

  In the above embodiment, by changing the twist pitch P of the inner fin 121 between the heat radiating pipe 120 located on the upstream side of the air passage 100 and the heat radiating pipe 120 located on the downstream side, As described above, the heat release degree is different. Instead of changing the twist pitch P of the inner fin 121, a plurality of through holes 122 for allowing combustion gas to pass therethrough are formed in the inner fin 121 as shown in FIG. It is also possible to change the degree of heat radiation for each heat radiating pipe 120 by changing the number and size of the through holes 122 between the upstream side and the downstream side. Specifically, the inner fin 121 inserted into the heat radiating pipe 120 on the upstream side (upper side in FIG. 3) is more than the inner fin 121 inserted into the radiating pipe 120 on the downstream side (lower side in FIG. 3). Since the through-hole 122 is provided in a wide range and the flow of combustion gas is better than that of the heat radiating pipe 120 on the downstream side, the degree of heat radiation is small. Thereby, the effect similar to the said embodiment is exhibited.

  In addition, as shown in FIG. 4, the heat radiation for each heat radiating pipe 120 is changed by changing the plate width of the inner fin 121 between the heat radiating pipe 120 located on the upstream side of the air passage 100 and the heat radiating pipe 120 located on the downstream side. The degree may be different. Specifically, the upstream side (upper side in FIG. 4) radiating pipe 120 is provided with an inner fin 121 having a plate width smaller than that of the downstream side (lower side in FIG. 4) radiating pipe 120. Therefore, the degree of heat radiation is small. Thereby, the effect similar to the said embodiment is exhibited.

  Further, as shown in FIG. 5, the heat dissipating pipe 120 located on the upstream side of the air passage 100 and the heat dissipating pipe 120 located on the downstream side use pipes having different diameters, and the inner fins 121 according to the pipe diameter. It is good also as what changed the heat dissipation degree for every heat radiating pipe 120 by changing the board width of this. Specifically, the upstream side (upper side in FIG. 4) radiating pipe 120 has a smaller diameter than the downstream side (lower side in FIG. 4) radiating pipe 120. An inner fin 121 having a plate width smaller than that of the downstream side heat radiating pipe 120 is inserted into the upstream side heat radiating pipe 120. Therefore, the degree of heat dissipation is smaller than that of the downstream side heat radiating pipe 120. Thereby, the effect similar to the said embodiment is exhibited.

DESCRIPTION OF SYMBOLS 1 Hot air heater 100 Air passage 11 Combustion part 12 Heat exchanger 120 Radiation pipe 121 Inner fin

Claims (2)

A heat exchanger that releases the heat of the combustion gas sent from the combustion section and heats the air introduced into the air passage,
A heat dissipating pipe extending in a direction intersecting the air flow direction in the air passage and arranged in parallel in the flow direction;
Provided with a spiral plate-like inner fin that is provided over substantially the entire length of each radiating pipe and turbulently flows the combustion gas fed into the radiating pipe,
Among the plurality of heat radiating pipes arranged in the flow direction, the heat radiating pipes located on the upstream side are located on the downstream side so that the heat radiating degree of the heat radiating pipes located on the upstream side is smaller than the heat radiation degree of the heat radiating pipes located on the downstream side. A heat exchanger characterized in that the shape of the inner fin is different from that of the heat radiating tube. The heat exchanger according to claim 1,
A heat exchanger characterized in that the twist pitch of the inner fin of the heat radiating pipe located on the upstream side is made larger than the twist pitch of the inner fin of the heat radiating pipe located on the downstream side.

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