JP2015040645A - Latent heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a latent heat exchanger favorable in heat exchange efficiency.SOLUTION: A latent heat exchanger comprises: box bodies (14, 16 and 18) having combustion gas flow-in ports 15 at bottom faces and combustion gas flow-out ports 17 at upper faces; a cylindrical guide cylinder 19 opened at an upper end which takes in combustion gas flowing in from the combustion gas flow-in ports 15 from a lower end, and guides the gas to upper regions in the box bodies (14, 16 and 18); a cylindrical rectifying cylinder 20 which covers an outer periphery of the guide cylinder 19, and is closed at upper end so that a flow of the combustion gas from the guide cylinder 19 is turned; and a heat receiving pipe 22 which is wound around into a space formed between an outer peripheral face of the rectifying cylinder 20 being an outer periphery of the rectifying cylinder 20 and inner walls of the box bodies (14, 16 and 18), and collects latent heat from the combustion gas. A plurality of rectifying holes 21 through each of which the combustion gas is blown out to a side peripheral face of the rectifying cylinder 20 are formed, and the combustion gas which is rectified by the rectifying hole 21 is made to contact with the heat receiving pipe 22.

Description

  The present invention relates to a latent heat exchanger that recovers latent heat from combustion gas.

  Conventionally, as this type of latent heat exchanger, a heat receiving pipe that circulates water as a fluid to be heated is formed in a spiral shape, and latent heat is generated from a combustion gas as a heating fluid that passes through the gap between the upper and lower adjacent heat receiving pipes. There are some which are recovered, and this configuration makes the heat exchange efficiency good by bringing the combustion gas into contact with the heat absorption tube efficiently. (For example, refer to Patent Document 1.)

JP-A-2005-321170

  By the way, in this conventional latent heat exchanger, there are variations in the size of the gap between the upper and lower heat receiving tubes, and it is difficult to make it constant, and there is also a size in the gap between the heat receiving tubes. For example, if there is a large gap, the amount of passage of the combustion gas is large, but the combustion gas passing through the portion close to the heat receiving pipe is heat-exchanged, while the combustion gas flowing through the central portion of the gap is heat It passes without being exchanged, and there is an increase in the amount of combustion gas that does not contribute to heat exchange and the heat exchange efficiency does not increase. Conversely, if there is a space with a small gap, the combustion gas does not pass, or between the heat receiving tubes Combustion gas is taken in a place with a large gap and the amount of heat exchange is small and heat exchange efficiency may deteriorate, and the presence of the gap between the heat receiving tubes makes the combustion gas before contacting the heat receiving tubes. Will be formed uneven flow, it had a problem that lowers the heat exchange efficiency.

  In order to solve the above-mentioned problems, the present invention is particularly configured as claimed in claim 1, a housing having a combustion gas inlet on the bottom surface and a combustion gas outlet on the top surface, and an inflow from the combustion gas inlet. A cylindrical guide tube having an open upper end for taking in combustion gas from the opened lower end and guiding it to the upper region in the casing; and covering the outer periphery of the guide tube and turning back the flow of the combustion gas from the guide tube A cylindrical rectifier cylinder whose upper end is closed, and an outer periphery of the rectifier cylinder, which is wound in a space formed between the outer peripheral surface of the rectifier cylinder and the inner wall of the housing A heat receiving pipe for recovering latent heat from the gas, and a plurality of flow straightening holes through which the combustion gas is blown out are formed on a side peripheral surface of the flow straightening cylinder, and the combustion gas rectified by the flow straightening holes is supplied to the heat receiving pipe. The contact was made.

  According to a second aspect of the present invention, the opening ratio of the rectifying hole per unit area of the rectifying cylinder is increased from the upper part to the lower part of the rectifying cylinder.

  According to the first aspect of the present invention, when the combustion gas is blown out from the rectifying hole of the rectifying cylinder, the flow of the combustion gas is uniformly rectified by the rectifying hole and is blown out toward the heat receiving tube in that state. Thus, the non-uniform flow of the combustion gas is not formed before it contacts the heat receiving pipe, and the heat exchange efficiency between the water flowing through the heat receiving pipe and the combustion gas can be improved.

  According to the second aspect of the present invention, the combustion gas tends to flow from the rectifying hole provided in the upper part of the rectifying cylinder so as to go to the combustion gas outlet, so that the rectifying hole is changed from the upper part of the rectifying cylinder to the lower part. By increasing the opening ratio of the flow straightening hole per unit area of the flow straightening tube, the combustion gas is more easily flowed to the lower side of the flow straightening tube so that the combustion gas is evenly distributed from the entire flow straightening tube. The heat exchange efficiency can be improved by bringing the combustion gas into contact with the entire heat receiving tube evenly.

1 is a schematic cross-sectional view of a latent heat recovery type water heater provided with a latent heat exchanger showing an embodiment of the present invention. The disassembled perspective view of the latent heat exchanger of the same embodiment.

Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a latent heat exchanger 4 according to an embodiment of the present invention, which constitutes a part of a latent heat recovery type hot water heater 1. The latent heat recovery type hot water heater 1 is a sensible heat exchanger. A cylindrical hot water storage can body 2, a burner unit 3 for burning petroleum fuel, a latent heat exchanger 4 installed above the hot water storage can body 2, and neutralizing the drain generated in the latent heat exchanger 4 It is composed of a sum machine 5.

  The hot water storage can body 2 stores a certain amount of hot water therein, a combustion chamber 6 is formed inside the lower portion of the hot water storage can body 2, and a heat exchange pipe constituting a number of flues in the hot water storage can body 2. 7 is arranged, and at the upper part of the hot water storage can body 2 is formed an exhaust collecting portion 8 that communicates with the heat exchange pipe 7 and flows out the combustion gas generated in the burner portion 3 to the latent heat exchanger 4 side. It is. Note that 9 is a hot water storage temperature sensor for detecting the temperature of hot water in the hot water storage can body 2, and 10 is a hot water supply that is connected to the upper portion of the hot water storage can body 2 and appropriately supplies the hot water stored in the hot water storage can body 2 to the hot water supply required location It is a tube.

  The burner unit 3 includes an ignition electrode 11, a nozzle 12 that supplies fuel, and a combustion fan 13 that supplies combustion air, and combustion gas generated by the combustion of the burner unit 3 facing the combustion chamber 6 is combusted. When passing through the heat exchange pipe 7 communicating with the chamber 6, heat exchange is performed between the high-temperature combustion gas in the heat exchange pipe 7 and the hot water in the hot water storage can body 2. The hot water is heated to a high temperature.

  The latent heat exchanger 4 includes a cylindrical body portion 14 having the same diameter as the hot water storage can body 2 and opened at the upper and lower ends, and the lower end of the body portion 14 is closed, and combustion gas from the exhaust collecting portion 8 is passed into the body portion 14. The bottom plate 16 having the combustion gas inlet 15 that flows into the bottom plate 16 and the top plate 18 having the combustion gas outlet 17 that closes the upper end of the body portion 14 and flows the combustion gas that has passed through the body portion 14 to the outside. The housing of the heat exchanger 4 is configured.

  In the body portion 14, the combustion gas that has flowed into the body portion 14 through the exhaust inlet 15 provided at the center of the bottom plate 16 is taken in from the open lower end, and the upper region in the body portion 14. A cylindrical guide tube 19 having an open upper end that is guided to the bottom is erected on the bottom plate 16 so as to surround the exhaust inlet 15, and covers the outer periphery of the guide tube 19 at a predetermined interval. Is arranged on the bottom plate 16, and a plurality of rectifying holes 21 are formed on the side peripheral surface of the rectifying cylinder 20 as a plurality of holes having substantially the same diameter for blowing combustion gas. Has been. The rectifying hole 21 is formed by burring, and has a rising edge projecting outward of the rectifying cylinder 20 at its peripheral edge.

  Further, a heat receiving pipe 22 for recovering latent heat from the combustion gas is accommodated in the body portion 14, and the heat receiving pipe 22 is formed in a spiral shape, and water as a fluid to be heated circulates therein. Yes, it is wound around the outer periphery of the rectifying cylinder 20 and in the space formed between the outer peripheral surface of the rectifying cylinder 20 and the inner wall of the body portion 14.

  Further, a water inflow connection port 24 to which a water supply pipe 23 is connected is provided on the side peripheral surface of the body portion 14, and one end (upstream end) of the water supply pipe 23 and the heat receiving pipe 22 is connected via the water inflow connection port 24. ) And the water supplied from the water supply pipe 23 flows into the heat receiving pipe 22 of the latent heat exchanger 4. Further, a water outflow connection port 26 to which a connecting pipe 25 that connects the latent heat exchanger 4 and the hot water storage can body 2 is connected is provided on the side peripheral surface of the body portion 14. The other end (downstream end) of the heat receiving pipe 22 and the connecting pipe 25 are connected to each other, and latent heat is recovered and heated hot water flows out from the heat receiving pipe 22 to the connecting pipe 25. Further, a drain drainage connection port 28 to which a drain pipe 27 that guides the drain generated in the latent heat exchanger 4 to the neutralizer 5 is connected to the lower portion of the side peripheral surface of the body portion 14. .

  The neutralizer 5 is filled with a neutralizing agent (not shown) for neutralizing the drain, neutralizes the drain led from the drain pipe 27 to the neutralizer 5, The summed drain is discharged to the outside through the drain pipe 29.

Next, the operation of the latent heat recovery type water heater 1 will be described.
When a hot water supply faucet (not shown) appropriately provided at a hot water supply location is opened, hot water in the hot water storage can body 2 is discharged by the hot water supply pipe 10 and hot water supply is started. At the same time, water from the water supply pipe 23 flows into the heat receiving pipe 22, flows through the heat receiving pipe 22, and flows from the heat receiving pipe 22 into the hot water storage can body 2 through the connecting pipe 25.

  When the temperature of the hot water in the hot water storage can body 2 gradually decreases and the temperature detected by the hot water storage temperature sensor 9 falls below a predetermined temperature, combustion is started in the burner unit 3, and the combustion gas is discharged from the combustion chamber 6. When passing through the heat exchange pipe 7 in the hot water storage can body 2, heat is exchanged between the high-temperature combustion gas in the heat exchange pipe 7 and the water stored in the hot water storage can body 2 to be heated fluid in the hot water storage can body 2. As the water is heated.

  The combustion gas that has absorbed the sensible heat through the heat exchange pipe 7 flows into the body portion 14 from the exhaust collecting portion 8 through the combustion gas inlet 15. The combustion gas flowing into the body portion 14 is guided from the combustion gas inlet 15 to the upper region in the body portion 14 by the guide tube 19, and the combustion gas that has moved up the guide tube 19 hits the upper surface of the rectifying tube 20 and makes a U-turn. The gas flows down to the space between the guide cylinder 19 and the rectifying cylinder 20, and the combustion gas is blown out of the rectifying cylinder 20 through a plurality of rectifying holes 21 provided in the rectifying cylinder 20 to come into contact with the heat receiving pipe 22.

  Here, when the combustion gas is blown out from the flow straightening hole 21 of the flow straightening cylinder 20, the flow of the combustion gas is uniformly rectified by the flow straightening hole 21, and is blown out toward the heat receiving pipe 22 in that state. A non-uniform flow of the combustion gas is not formed before contacting the heat exchanger 22, and the heat exchange efficiency between the water flowing through the heat receiving pipe 22 and the combustion gas can be improved. The number, size, and arrangement of the rectifying holes 21 are appropriately set so that the flow of the combustion gas blown out from the rectifying cylinder 20 is uniform, and the rectifying holes 21 are used when the rectifying cylinder 20 is manufactured. There is little variation and it is easy to obtain dimensional accuracy.

  Then, the combustion gas blown out from the flow straightening cylinder 20 contacts the heat receiving pipe 22 to exchange heat, rises toward the upper surface plate 18 side, and from the combustion gas outlet 17 provided at the center of the upper surface plate 18. When the heat is exchanged between the water as the heated fluid flowing through the heat receiving pipe 22 and the combustion gas as the heating fluid in the latent heat exchanger 4, the water vapor in the combustion gas is discharged outside. When the dew point is below the dew point, strongly acidic drain is generated on the surface of the heat receiving tube 22, and the generated drain accumulates on the bottom plate 16 between the flow straightening cylinder 20 and the inner wall of the body portion 14. When it reaches the level of the drain drainage connection port 28, it flows into the drain pipe 27 and flows into the neutralizer 5, where it is neutralized by contact with the neutralizer in the neutralizer 5, and the neutralized drain is drained. It is drained into sewage at a predetermined location through the pipe 29.

  The present invention is not limited to the embodiment described above. In this embodiment, a plurality of rectifying holes 21 are formed in the rectifying cylinder 20, but the rectifying holes 21 have the same diameter and the same diameter. When the holes are sized, the combustion gas tends to flow from the rectifying holes 21 provided in the upper part of the rectifying cylinder 20 so as to go to the combustion gas outlet port 17. By forming so that the number of the rectification holes 21 increases toward the bottom, the opening ratio of the rectification holes 21 per unit area of the rectification cylinder 20 increases from the upper part to the lower part of the rectification cylinder 20 so that the rectification is performed. The combustion gas may be configured to easily flow to the lower side of the cylinder 20 so that the combustion gas is blown out uniformly from the entire rectifying cylinder 20, so that the entire heat receiving pipe 22 is evenly combusted. Gas contact Further, the heat exchange efficiency can be improved, and further, the flow straightening tube 20 is formed so that the size of the flow straightening hole 21 increases from the top to the bottom of the flow straightening tube 20. The opening ratio of the rectifying hole 21 per unit area of the rectifying cylinder 20 increases from the upper part to the lower part of the rectifying cylinder 20 so that the combustion gas easily flows to the lower side of the rectifying cylinder 20, and the combustion gas is rectified. You may make it blow off from the whole pipe | tube 20 equally, and, by doing so, can make a combustion gas contact the whole heat receiving pipe 22 equally, and can improve heat exchange efficiency.

4 Latent Heat Exchanger 14 Body 15 Combustion Gas Inlet 16 Bottom Plate 17 Combustion Gas Outlet 18 Top Plate 19 Guide Tube 20 Rectifier Tube 21 Rectifier Hole 22 Heat Receiving Tube

Claims (2)

  A casing having a combustion gas inlet on the bottom surface and a combustion gas outlet on the top surface, and an upper end for taking in the combustion gas flowing in from the combustion gas inlet from the opened lower end and guiding it to the upper region in the casing. An open cylindrical guide tube, a cylindrical rectifier tube covering an outer periphery of the guide tube and closed at an upper end so as to fold back the flow of the combustion gas from the guide tube, and an outer periphery of the rectifier tube, A heat receiving pipe that is wound in a space formed between the outer peripheral surface of the rectifying cylinder and the inner wall of the housing and collects latent heat from the combustion gas. A latent heat heat exchanger, wherein a plurality of rectifying holes through which combustion gas is blown out are formed, and the combustion gas rectified by the rectifying holes is brought into contact with the heat receiving pipe.   The latent heat heat exchanger according to claim 1, wherein an opening ratio of the rectifying hole per unit area of the rectifying cylinder is increased from the upper part to the lower part of the rectifying cylinder.

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