JP6224443B2 - Latent heat exchanger and latent heat recovery water heater - Google Patents

Description

The present invention relates to a latent heat exchanger that recovers latent heat from combustion gas and a latent heat recovery type water heater .

  Conventionally, as a latent heat exchanger for recovering latent heat from combustion gas, as shown in FIG. 5, between a pair of cylindrical headers (inflow header 101 and outflow header 102) of the same size (internal volume is equal). A plurality of heat receiving tubes 103 are connected, and the plurality of heat receiving tubes 103 are stacked in the vertical direction. (For example, refer to Patent Document 1.)

JP 2008-170088 A

  By the way, in the water heater provided with the latent heat exchanger as shown in FIG. 5, the sensible heat exchanger for recovering sensible heat from the combustion gas is a hot water storage type heat exchanger, and a pressure reducing valve is provided in the middle of the water passage. If the pressure of the water supply is reduced, or if the length of the water supply pipe from the water heater to the hot water tap provided in the house is complicated and the length of the water supply pipe is long, the hot water pressure is weak or the hot water flow rate is low There is.

  Here, when water is supplied to the latent heat exchanger for the first time after the water heater is installed, water is drained to prevent freezing of the flow path of the heat receiving pipe 103 of the latent heat exchanger in the water heater. When the water flows again after that, the water flowing into the inflow header 101 flows from the inflow header 101 into the heat receiving pipes 103 and collects in the outflow header 102 and flows out to the outside, as described above. When the hot water supply pressure is weak or the hot water supply flow rate is small, the air cannot be pushed out completely, and as shown in FIG. 6 showing the latent heat exchanger viewed from the direction of the arrow in FIG. There is a possibility that air may accumulate in the heat receiving pipe 103. If the air is in the accumulated state, the portion does not contribute to the heat exchange, and the heat exchange efficiency is lowered. It was.

In order to solve the above-mentioned problems, the present invention is configured in particular in claim 1 to include a casing having a combustion gas flow passage therein, a plurality of heat receiving pipes accommodated in the casing, and the heat receiving pipes. An inflow header connected to an upstream end to allow water to flow into the heat receiving pipe; and an outflow header to which a downstream end of the heat receiving pipe is connected to flow out water from the heat receiving pipe, and the heat receiving pipe is stacked in a vertical direction. In the latent heat exchanger that allows water to flow between the inflow header and the outflow header in the horizontal direction, the internal volume of the outflow header is made smaller than the internal volume of the inflow header.

According to a second aspect of the present invention, a burner section, a hot water storage type sensible heat exchanger that recovers sensible heat from the combustion gas generated by the combustion of the burner section, and latent heat from the combustion gas that has passed through the sensible heat exchanger. A latent heat recovery type hot water supply apparatus having a latent heat exchanger for recovering, a water supply pipe connected to the latent heat exchanger, and a pressure reducing valve provided in the water supply pipe, wherein the latent heat exchanger A casing having a combustion gas flow path therein, a plurality of heat receiving pipes accommodated in the casing, the water supply pipe is connected, water from the water supply pipe flows into the interior, and upstream of the heat receiving pipe And an inflow header for connecting water to the heat receiving pipe and an outflow header for connecting the downstream end of the heat receiving pipe to which water from the heat receiving pipe flows out, and the heat receiving pipe is stacked in the vertical direction. A horizontal passage is provided between the inflow header and the outflow header. So as to, and it shall reduce the internal volume of the outflow header than the internal volume of the inflow header.

  According to the first aspect of the present invention, the inner volume of the outflow header is made smaller than the inner volume of the inflow header, thereby pushing out air that is to remain in the heat receiving pipe when water is first passed through the latent heat exchanger. Thus, there is no state in which air is accumulated in the heat receiving pipe, and a decrease in heat exchange efficiency can be prevented.

According to the second aspect of the present invention, the burner part, a hot water storage type sensible heat exchanger that recovers sensible heat from the combustion gas generated by the combustion of the burner part, and the latent heat from the combustion gas after passing through the sensible heat exchanger. In a latent heat recovery type water heater having a latent heat exchanger that collects the heat, a water supply pipe connected to the latent heat exchanger, and a pressure reducing valve provided in the water supply pipe, the inner volume of the inflow header of the latent heat exchanger Even if the water supply pressure is reduced by the pressure reducing valve and the hot water pressure is weak or the hot water flow rate is low when the water flow through the latent heat exchanger for the first time, etc. The air that tries to remain in the tube can be pushed out, there is no state in which the air is accumulated in the heat receiving tube, and a decrease in heat exchange efficiency can be prevented.

The perspective view of the latent heat exchanger which shows one Embodiment of this invention. The header sectional view of the latent heat exchanger of the same embodiment. Schematic of the latent heat recovery type water heater provided with the latent heat exchanger of the same embodiment. The figure showing the state of the water in a header and a heat receiving pipe at the time of water flow of the latent heat exchanger of the same embodiment. The perspective view of the conventional latent heat exchanger. The figure showing the state of the water in a header and a heat receiving pipe at the time of water flow of the conventional latent heat exchanger.

Next, a latent heat exchanger according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the latent heat exchanger 1 includes a plurality of heat receiving tubes 2, a cylindrical inflow header 3 to which the upstream end of the heat receiving tube 2 is connected, and a cylinder to which the downstream end of the heat receiving tube 2 is connected. The heat receiving pipe 2 has a meandering shape, and a plurality of the heat receiving pipes 2 are stacked in the vertical direction with an interval therebetween, and a horizontal direction is provided between the inflow header 3 and the outflow header 4. The heat receiving pipes 2 adjacent to each other in the upper and lower sides are arranged with a pitch shifted, whereby a turbulent flow occurs in the combustion gas and heat exchange is promoted.

  Here, FIG. 2 is a simplified cross-sectional view of the inflow header 3 and the outflow header 4. The height of the inflow header 3 and the height of the outflow header 4 are the same, but from the diameter of the inflow header 3. Also, the diameter of the outflow header 4 is smaller, the internal volume V2 of the outflow header 4 is smaller than the internal volume V1 of the inflow header 3, and the internal volume V1 of the inflow header 3> the internal volume V2 of the outflow header 4 It has the relationship.

  Moreover, as shown in FIG. 3, the latent heat exchanger 1 constitutes a part of the latent heat recovery type hot water heater 5, and the latent heat recovery type hot water heater 5 recovers sensible heat from the combustion gas. A cylindrical hot water storage can 6 as a heat exchanger, a burner portion 7 for burning petroleum fuel, a silencer 9 that is installed above the hot water storage can 6 and has a silencer 8 such as rock wool or glass wool inside. The latent heat exchanger 1, the flat box-shaped communication path 10 installed above the latent heat exchanger 1 and the muffling unit 9, and the combustion gas generated in the burner unit 7 connected to the communication path 10 to the outside The exhaust cylinder 11 to be discharged and the neutralizer 12 for neutralizing the drain generated in the latent heat exchanger 1 are configured.

  The hot water storage can body 6 stores a certain amount of hot water therein, a combustion chamber 13 is formed inside the hot water storage can body 6, and a heat exchange pipe 14 constituting a large number of flues in the hot water storage can body 6. Are arranged, and a can body combustion gas outlet 15 is formed at the upper part of the hot water storage can body 6 to allow the combustion gas generated in the burner section 7 to flow out to the muffler section 9. A hot water storage temperature sensor 16 detects the temperature of hot water in the hot water storage can body 6, and 17 is a hot water storage can body 6 that is connected to the lower portion of the hot water storage can body 6 and preheated by the heat receiving pipe 2 of the latent heat exchanger 1. A connecting pipe 18 is connected to the upper portion of the hot water storage can body 6 and is a hot water supply pipe for supplying hot water stored in the hot water storage can body 6 to a hot water tap (not shown) appropriately provided in the user's house.

  The burner unit 7 includes an ignition electrode 19, a nozzle 20 for supplying fuel, and a combustion fan 21 for supplying combustion air. Combustion gas generated by combustion of the burner unit 7 facing the combustion chamber 13 is burned. When passing through the heat exchange pipe 14 communicating with the chamber 13, heat exchange is performed between the high-temperature combustion gas in the heat exchange pipe 14 and the stored water in the hot water storage can body 6, and the hot water in the hot water storage can body 6. Is heated to a high temperature.

  The silencer 9 includes a silencer combustion gas inlet 22 through which the combustion gas from the can combustion gas outlet 15 flows, a silencer 8, and a silencer combustion gas flow path formed in the silencer 9 and through which the combustion gas passes. 23 and a silencer combustion gas outlet 24 through which the combustion gas that has passed through the silencer combustion gas flow path 23 flows out to the latent heat exchanger 1.

  The latent heat exchanger 1 includes a casing 25 that accommodates the heat receiving pipe 2, the inflow header 3, and the outflow header 4 therein, and the latent heat exchanger 1 is constituted by the heat receiving pipe 2, the inflow header 3, the outflow header 4, and the casing 25. The casing 25 has a latent heat exchange gas inlet 26 through which the combustion gas from the muffler combustion gas outlet 24 flows into the casing 25, and the combustion gas is contained in the casing 25. A latent heat exchange combustion gas passage 27 is formed, and a latent heat exchange combustion gas outlet 28 is formed on the upper surface of the casing 25 to allow the combustion gas that has passed through the latent heat exchange combustion gas passage 27 to flow out to the communication passage 10. A drain drainage connection port 30 connected to a drain pipe 29 that guides drain generated in the latent heat exchanger 1 to the neutralizer 12 is provided on the bottom surface of the casing 25. Is shall.

  The inflow header 3 is provided with an inflow connection port 32 that is connected to the water supply pipe 31 and allows water from the water supply pipe 31 to flow into the inflow header 3. The water supply pressure is reduced in the middle of the water supply pipe 31. A pressure reducing valve 33 is provided. The outflow header 4 is connected to one end of a connecting pipe 17 that connects the latent heat exchanger 1 and the hot water storage can 6, and the outflow connection port through which the hot water heated by the latent heat exchanger 1 flows out from the outflow header 4. 34 is provided.

  The communication passage 10 includes a communication passage combustion gas inlet 35 through which combustion gas from the latent heat heat exchange combustion gas outlet 28 flows, a communication passage combustion gas passage 36 formed in the communication passage 10 and through which the combustion gas passes, and a communication passage. A communication passage combustion gas outlet 37 through which the combustion gas that has passed through the combustion gas flow path 36 flows out to the exhaust cylinder 11 is provided.

  The neutralizer 12 is filled with a neutralizing agent (not shown) for neutralizing the drain therein, neutralizes the drain led from the drain pipe 29 to the neutralizer 12, The summed drain is discharged to the outside through the drain pipe 38.

Next, the operation of the latent heat recovery type water heater 5 will be described.
When a hot water tap (not shown) provided as appropriate in the user's house is opened, hot water in the hot water storage can 6 is discharged from the hot water supply pipe 18 and hot water supply is started. At the same time, water flows into the inflow header 3 from the water supply pipe 31, the water flows into the heat receiving pipes 2 from the inflow header 3, and the water that has passed through the heat receiving pipes 2 flows from the heat receiving pipes 2 to the outflow header 4. And flows into the hot water storage can 6 through the connecting pipe 17 from the outflow header 4.

  When the temperature of the hot water in the hot water storage can 6 gradually decreases and the temperature detected by the hot water storage temperature sensor 16 falls below a predetermined temperature, combustion is started in the burner unit 7, and the combustion gas is discharged from the combustion chamber 13. When passing through the heat exchange pipe 14 in the hot water storage can 6, heat is exchanged between the high-temperature combustion gas in the heat exchange pipe 14 and the stored water in the hot water storage can 6 to be heated in the hot water storage can 6. As the water is heated.

  The combustion gas that has absorbed the sensible heat through the heat exchange pipe 14 passes through the can body combustion gas outlet 15 and flows into the silencer 9 from the silencer combustion gas inlet 22. The combustion gas that has flowed into the silencer 9 is still high in temperature, has a high sound velocity, and has a short wavelength even at the same frequency. Therefore, by arranging the silencer 9 upstream of the latent heat exchanger 1, the silencer 9 having a small volume can be used. It can effectively mute low frequencies. In addition, by disposing the silencer 9 on the upstream side of the latent heat exchanger 1 as the flow direction of the combustion gas, the temperature has not yet dropped to the extent that the combustion gas produces drainage, and the silencer 8 is corroded by the drain. It can be prevented.

  The combustion gas that has passed through the silencer 9 flows into the casing 25 of the latent heat exchanger 1 from the latent heat exchanger gas inlet 26, and the combustion gas that passes through the latent heat exchanger gas channel 27 in the casing 25 is The latent heat of the latent heat exchanger 1 is heated by exchanging heat with water flowing through the plurality of heat receiving pipes 2 and the inflow header 3 and the outflow header 4 accommodated in the casing 25 and flowing into the hot water storage can 6. The combustion gas that has passed through the alternating combustion gas flow path 27 and has absorbed latent heat passes through the latent heat heat exchange combustion gas outlet 28, flows into the communication passage 10, passes through the communication passage 10, and is exhausted to the outside from the exhaust cylinder 11. Is.

  In the latent heat exchanger 1, when water as the heated fluid flowing through the plurality of heat receiving tubes 2 and the combustion gas as the heating fluid are subjected to heat exchange, the water vapor in the combustion gas becomes lower than the dew point. As a result, strongly acidic drain is generated on the surface of the heat receiving pipe 2 in contact with the combustion gas and the surfaces of the inflow header 3 and the outflow header 4, and the generated drain is collected on the bottom surface of the casing 25 and led to the drain drain connection port 30. It will be. The drain generated in the latent heat exchanger 1 passes through the drain pipe 29 from the drain drain connection port 30 and flows into the neutralizer 12, and is neutralized by contacting with the neutralizer in the neutralizer 12. The drain thus drained is drained into sewage at a predetermined location via the drain pipe 38.

  Next, the latent heat exchanger 1 viewed from the direction of the arrow in FIG. 1 is shown with respect to the state of water in the heat receiving pipe 2 and the inflow header 3 and the outflow header 4 when the latent heat exchanger 1 is passing water. This will be described with reference to FIG. In addition, the dotted line in FIG. 4 shall represent the water in the heat receiving pipe 2, the inflow header 3, and the outflow header 4. FIG.

  When the latent heat recovery type hot water heater 5 is installed for the first time when water is passed through the latent heat exchanger 1, or the flow path through which water flows in the heat receiving pipe 2 of the latent heat exchanger 1 in the latent heat recovery type hot water heater 5 is frozen. For example, when water is drained for prevention, the water flowing into the inflow header 3 flows into the heat receiving pipes 2 separately from the inflow header 3 and collects in the outflow header 4 from the outflow header 4. In this case, the inner volume V1 of the inflow header 3 and the inner volume V2 of the outflow header 4 have a relationship of V1> V2, so that the heat receiving pipe 2 is supplied. As shown in FIG. 4, the heat receiving pipe 2, the inflow header 3 and the outflow header 4 have no air and are filled with water as shown in FIG. is there.

  Therefore, as in this embodiment, the sensible heat exchanger is a hot water storage type heat exchanger (hot water storage can body 6), and the pressure reducing valve 33 is provided in the middle of the water passage to reduce the feed water pressure, or latent heat. The piping of the water supply pipe from the recovery type water heater 5 to the hot water tap (not shown) appropriately provided in the house is complicated and the length of the water supply pipe is long, so the pressure of the hot water supply is weak or the flow rate of the hot water supply is small Even in this case, the air can be pushed out, and there is no state in which the air is accumulated in the uppermost heat receiving pipe 2 as shown in FIG. 6 described above, thereby preventing a decrease in heat exchange efficiency. It is something that can be done.

  Note that the present invention is not limited to the embodiment described above, and in the latent heat exchanger 1 of the present embodiment, the heat receiving tubes 2 are stacked in a vertical row at intervals in the vertical direction. However, if the internal volume V1 of the inflow header 3 and the internal volume V2 of the outflow header 4 have a relationship of V1> V2, the heat receiving pipe 2 is not only in the vertical direction (column direction) but also in the lateral direction. A plurality of them arranged in parallel in the direction (row direction) may be arranged.

  In this embodiment, the inflow header 3 and the outflow header 4 are disposed in the casing 25. However, the relationship between the internal volume V1 of the inflow header 3 and the internal volume V2 of the outflow header 4 is V1> V2. The inflow header 3 and the outflow header 4 may be disposed outside the casing 25.

DESCRIPTION OF SYMBOLS 1 Latent heat exchanger 2 Heat receiving pipe 3 Inflow header 4 Outflow header
5 Latent heat recovery type water heater
6 Hot water storage can (sensible heat exchanger)
7 Burner section 25 Casing
31 Water supply pipe
33 Pressure reducing valve

Claims (2)

A casing having a combustion gas flow path therein; a plurality of heat receiving pipes housed in the casing; an inflow header to which an upstream end of the heat receiving pipe is connected and water flows into the heat receiving pipe; and An outlet header to which a downstream end is connected and water from the heat receiving pipe flows out, and the heat receiving pipe is stacked in a vertical direction so that water flows between the inflow header and the outflow header in a horizontal direction. In the latent heat exchanger, the inner volume of the outflow header is made smaller than the inner volume of the inflow header. Burner unit, hot water storage type sensible heat exchanger that recovers sensible heat from combustion gas generated by combustion of the burner unit, and latent heat heat exchanger that recovers latent heat from the combustion gas after passing through the sensible heat exchanger And a latent heat recovery type water heater having a water supply pipe connected to the latent heat exchanger and a pressure reducing valve provided in the water supply pipe, wherein the latent heat heat exchanger has a combustion gas flow path therein. A plurality of heat receiving pipes accommodated in the casing, the water supply pipe is connected to allow water from the water supply pipe to flow therein, and an upstream end of the heat receiving pipe is connected to the heat receiving pipe. An inflow header for allowing water to flow in, and an outflow header to which a downstream end of the heat receiving pipe is connected and water is discharged from the heat receiving pipe, and the heat receiving pipe is stacked in the vertical direction, and the inflow header and the outflow header So that the water flows horizontally between the Latent heat recovery type water heater, characterized in that to reduce the internal volume of the outflow header than the internal volume of the inflow header.

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