JP2008170088A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger capable of fully enhancing thermal efficiency by positively recovering latent heat of combustion gas exhausted. <P>SOLUTION: A tube 1 through which water W absorbing latent heat is piped in corrugated shape in a path of the combustion gas G exhausted. The tube 1 is held in a casing into which the combustion gas G is led, and straightening vanes 4 guiding the led-in combustion gas G along the corrugated piping of the tube 1 are provided in the casing. The tube 1 is piped in corrugated shape parallel in inclination from crest parts to trough parts, and the straightening vanes 4 are arranged parallel with the tube 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention belongs to a technical field related to a secondary (auxiliary) heat exchanger installed to recover the latent heat of exhausted combustion gas.

Recently, in a hot water supply apparatus using gas and oil as fuel, in addition to a primary heat exchanger for recovering sensible heat of combustion gas burned in the combustor, latent heat of exhausted combustion gas is recovered. A secondary heat exchanger is provided to improve thermal efficiency (fuel consumption) and reduce carbon dioxide (CO ₂ ) emissions. The primary heat exchanger is designed to have a structure in which acidic condensate is not generated while improving thermal efficiency using a copper-based metal material having high thermal conductivity as a manufacturing material. Since it is difficult to prevent the formation of acidic condensate, secondary heat exchangers are made of stainless steel, which has a low thermal conductivity, but is acid resistant. For this reason, regarding the secondary heat exchanger, it is desired to increase the thermal efficiency in terms of structure.

Conventionally, for example, a technique described in Patent Document 1 below is known as a technique aimed at increasing the thermal efficiency in terms of the structure of a secondary heat exchanger.
Patent Document 1 describes a heat exchanger in which a tube in which water that absorbs latent heat is circulated in a path of exhausted combustion gas is arranged in a waveform.

In the heat exchanger according to Patent Document 1, the tube is formed in a corrugated shape and the tube length of the tube is ensured to be long in a limited volume, thereby extending the heat exchange area and extending the heat exchange time to increase the thermal efficiency. Is.
JP 2005-214549 A

  In the heat exchanger according to Patent Document 1, the exhausted combustion gas simply passes linearly around the tube. Therefore, the tube piping is corrugated to expand the heat exchange area and extend the heat exchange time. Nevertheless, there is a problem in that the latent heat of the exhausted combustion gas is not sufficiently recovered and the thermal efficiency cannot be sufficiently increased.

  The present invention has been made in view of such problems, and provides a secondary heat exchanger that can reliably recover the latent heat of the exhausted combustion gas and sufficiently increase the thermal efficiency. Is an issue.

  In order to solve the above-described problems, the heat exchanger according to the present invention employs means described in each of the claims.

  That is, in claim 1, in a heat exchanger in which a tube through which water that absorbs latent heat is circulated in a path of exhausted combustion gas is provided in a waveform, the tube is accommodated in a casing into which combustion gas is introduced. The casing is provided with a rectifying plate for guiding the introduced combustion gas along the corrugated piping of the tube.

  In this means, the combustion gas introduced into the casing is guided along the corrugated piping of the tube, so that the heat exchange area is substantially expanded and the heat exchange time is greatly extended. .

  According to a second aspect of the present invention, in the heat exchanger according to the first aspect, the tube piping has a waveform in which the slope from the peak portion to the valley portion is parallel, and the rectifying plate is arranged in parallel with the tube. And

  In this means, the combustion gas introduced into the casing is swung at an angle of 180 degrees at the crests and troughs of the corrugated piping of the tube, so that latent heat can be recovered in the entire area inside the casing. .

  According to a third aspect of the present invention, in the heat exchanger according to the first or second aspect, a clearance is provided between the rectifying plate and the bottom surface of the casing.

  In this means, the clearance is provided between the current plate and the bottom surface of the casing, so that the condensate water generated inside the casing is prevented from accumulating.

  According to a fourth aspect of the present invention, in the heat exchanger according to any one of the first to third aspects, the rectifying plate is spot-attached to the upper part of the casing.

  In this means, the rectifying plate is spot-attached to the upper part of the casing, so that accumulation of condensed water generated inside the casing is prevented, and heat radiation of the combustion gas through the rectifying plate and the casing is avoided. .

  Further, according to claim 5, in the heat exchanger according to any one of claims 1 to 4, the tube is a header in which a plurality of thin tubes are stacked vertically and spaced to distribute and collect water flowing through the terminal. And the header is formed in a cylindrical shape with an axis orthogonal to the axis of the tube and is housed in the casing.

  In this means, since the header is formed in a cylindrical shape and accommodated in the casing, the header is also involved in the recovery of latent heat without hindering the flow of the combustion gas introduced into the casing.

  In the heat exchanger according to the present invention, the combustion gas introduced into the casing is guided along the corrugated piping of the tube, so that the heat exchange area is substantially expanded and the heat exchange time is drastically increased. Therefore, the latent heat of the exhausted combustion gas can be reliably recovered and the thermal efficiency can be sufficiently increased.

  Furthermore, as claimed in claim 2, the combustion gas introduced into the inside of the casing is swung at an angle of 180 degrees at the crests and troughs of the corrugated piping of the tube, so that the latent heat can be recovered in the entire area inside the casing. Since this is realized, there is an effect that the thermal efficiency is further improved.

  Furthermore, as claimed in claim 3, since the clearance is provided between the rectifying plate and the bottom surface of the casing, the accumulation of condensed water generated inside the casing is prevented, so that the acid deterioration of the rectifying plate, casing, etc. There is an effect to prevent.

  Further, as claimed in claim 4, the rectifying plate is spot-mounted on the upper part of the casing, so that accumulation of condensed water generated inside the casing is prevented, and heat dissipation of the combustion gas through the rectifying plate and the casing is prevented. Since it is avoided, there is an effect that acid deterioration of the current plate, casing, etc. is prevented and thermal efficiency is further improved.

  Furthermore, as claimed in claim 5, the header is formed in a cylindrical shape and accommodated in the casing, so that the header is also involved in the recovery of latent heat without hindering the flow of the combustion gas introduced into the casing. Therefore, there is an effect that the thermal efficiency is further increased.

  Hereinafter, the best mode for carrying out a heat exchanger according to the present invention will be described with reference to the drawings.

  In this form, as shown in FIG. 2, what is used for the hot water supply apparatus A which uses petroleum (kerosene) as a fuel is shown.

  This form is comprised by each part of the tube 1, the header 2, the casing 3, and the baffle plate 4 which used the stainless steel material etc. which are acid resistance as a manufacturing material.

  In the tube 1, water W that absorbs the latent heat of the exhausted combustion gas G is circulated, and eight narrow tubes of a corrugated pipe whose inclination from the peak portion to the valley portion is parallel to each other vertically. Are stacked. That is, the tube 1 is formed in a waveform in which end portions of parallel main pipe portions 11 are continuous by a semicircular curved pipe portion 12. The terminal 13 of the tube 1 is arrange | positioned in the position where the curved pipe part 12 side opposes.

  The header 2 distributes and collects the water W flowing through the inside of the tube 1. The header 2 is formed in a cylindrical shape in which one end surface of an axis orthogonal to the axis of the tube 1 is closed and is connected to both ends 13 of the tube 1. They are connected with each other. That is, the header 2 has a shape in which the tubes 1 are aligned with an interval in the vertical direction which is the axial direction. As a result, the assembled tube 1 and header 2 are ensured to have considerable assembly strength. One header 2 is used for water supply as an inlet. The other header 2 is for hot water supply for sending hot water H to the primary heat exchanger Aa of the hot water supply apparatus A as an outlet.

  The casing 3 introduces combustion gas G exhausted therein, and is formed in a box shape in which an upper lid portion 32 is welded or brazed to a rectangular cup portion 31. An inlet 33 for introducing the combustion gas G is opened on one side surface in the longitudinal direction of the cup portion 31. An introduction tube 34 connected to the flue Ab connected to the primary heat exchanger Aa of the hot water supply apparatus A is attached to the introduction port 33. A discharge port 35 for discharging the introduced combustion gas G to the outside of the body of the hot water supply device A is opened on the side surface in the short side direction near the other side surface in the longitudinal direction of the cup portion 31. Near the discharge port 35 on the bottom surface of the cup portion 31, there is a concave condensate receiver 36 that receives condensate water generated inside, and a drain connected to the condensate receiver 36 for allowing the condensed water to flow down to the neutralizer. A pipe 37 is provided. On both side surfaces of the cup portion 31 in the longitudinal direction, mounting brackets 38 and 39 for mounting and supporting the casing 3 on a machine frame or the like of the hot water supply apparatus A are provided.

  The casing 3 is installed in the upper part of the hot water supply apparatus A with the introduction port 33 and the introduction tube 34 facing upward and provided with an inclination of about 5 degrees in the longitudinal direction (see FIG. 2). Inside the casing 3, the header 2 is piped so as to penetrate the bottom surface of the cup portion 31, whereby the entire tube 1 and most of the header 2 are accommodated.

  The rectifying plate 4 regulates the flow path of the combustion gas G introduced by incompletely partitioning the inside of the casing 3 and is made of a thin plate to which the upper lid portion 32 of the casing 3 is attached. The rectifying plate 4 is formed in a U shape or an L shape in which upright pieces 42 are integrally provided at one end portion or both end portions of the substrate 41. The substrate 41 is provided with an emboss 43 for spot-attaching to the upper lid portion 32 located on the upper portion of the casing 3 by welding or brazing. The substrate 41 is opposed to the upper lid portion 32 of the casing 3 by an emboss 43 through a little clearance a. The upright pieces 42 are arranged in a staggered manner parallel to the center position between the main pipe parts 11 of the tube 1 via a little clearance b, c on the bottom and side surfaces of the cup part 31 of the casing 3. . In addition, about the length from the side surface of the cup part 31 of the standing piece 42, it is set to the centerline L vicinity which passes along the center between the curved pipe parts 12 of the tube 1, However, The air volume of the combustion gas G introduce | transduced into a casing It can be extended or shortened as appropriate.

  According to this embodiment, the combustion gas G exhausted from the flue Ab of the hot water supply apparatus A is introduced into the casing 3 through the introduction port 33 and the introduction cylinder 34, and the latent heat of the combustion gas G is introduced into the casing 3 by the tube 1. It will be collected.

  In the recovery of the latent heat of the combustion gas G, as in the heat exchanger according to Patent Document 1, a long pipe length is secured from the corrugated pipe of the tube 1, the heat exchange area is expanded, the heat exchange time is extended, and the thermal efficiency is increased. Has been enhanced. And since the combustion gas G introduced into the inside of the casing 3 is guided along the corrugated piping of the tube 1 by the standing piece 42 of the rectifying plate 4, the heat exchange area is substantially expanded and the heat exchange is performed. The time given to will be dramatically extended. Accordingly, it is possible to reliably recover the latent heat of the exhausted combustion gas G and sufficiently increase the thermal efficiency.

  Further, the combustion gas G guided by the upright piece 42 of the rectifying plate 4 is swung at an angle of 180 degrees in the vicinity of the curved pipe portion 12 of the tube 1 (see FIG. 4), and latent heat is recovered in the entire area inside the casing 1. Realization also contributes to improvement in thermal efficiency. In addition, the header 2 is formed in a cylindrical shape, accommodated in the casing 3 and involved in the recovery of latent heat without impeding the flow of the combustion gas G introduced into the casing 3. Contribute to.

  In addition, since the assembly | attachment intensity | strength equivalent to the connected tube 1 and the header 2 is ensured, an unnecessary vibration etc. are produced in the tube 1 etc. by distribution | circulation of the combustion gas G, and an abnormal noise is not generated. . Further, since the corrugated piping of the tube 1 can absorb the thermal expansion of the tube 1 or the like, the connection portion of the tube 1 and the header 2 is not damaged during use.

  Furthermore, in this embodiment, since the casing 3 is installed with an inclination, the condensed water generated inside the casing 3 naturally flows down to the condensed water receiver 36 and the drain pipe 37. Further, since the principle direction of introduction and exhaust of the combustion gas G in the casing 3 and the flow direction of the condensed water coincide with each other, the wind pressure of the combustion gas G assists the flow of the condensed water. Further, since clearances a, b, and C are provided between the base plate 41 and the standing piece 42 of the rectifying plate 4 and the bottom surface, the side surface, and the upper lid portion 32 of the cup portion 31 of the casing 3, the inside of the casing 3 is condensed. Water does not stay. Therefore, acidic deterioration of the casing 3, the current plate 4, etc. is reliably prevented.

  Further, clearances a, b, and C are provided between the substrate 41 and the standing piece 42 of the rectifying plate 4 and the bottom surface, side surface, and upper lid portion 32 of the cup portion 31 of the casing 3, and the substrate 41 of the rectifying plate 4 is embossed 43. Therefore, the combustion gas G does not dissipate unnecessarily through the rectifying plate 4 and the casing 3. Therefore, the thermal efficiency can be sufficiently increased.

  As described above, in addition to the illustrated embodiment, the number of thin tubes of the tube 1 and the pitch of the waveform of the piping can be appropriately changed.

  When the above-described hot water supply device A is for general household use, if heating at about 1500 ° C. is performed by the primary heat exchanger Aa, the temperature of the combustion gas G introduced into the casing 3 is about 200 ° C. However, the temperature of the combustion gas G exhausted from the casing 3 can be reduced to 60 ° C. by recovering the latent heat with the heat exchanger according to the present invention. That is, the thermal efficiency of the hot water supply apparatus A can be increased from about 83% to about 95%.

  The heat exchanger according to the present invention can be used in a wide range of fields other than a hot water supply device as a secondary one installed to recover the latent heat of exhausted combustion gas.

It is a perspective view of the best form for implementing the heat exchanger which concerns on this invention. It is a front view which shows the example of an assembly for utilizing for the hot-water supply apparatus of FIG. FIG. 3 is an enlarged longitudinal sectional view of a main part of FIG. 2. FIG. 3 is an enlarged cross-sectional view of a main part of FIG. 2.

Explanation of symbols

1 Tube 13 Terminal 2 Header 3 Casing 31 Cup part 32 Upper lid part (upper part)
4 Rectifying plate A Hot water supply device Aa Primary heat exchanger G Combustion gas W Water H Hot water

Claims (5)

  In a heat exchanger in which a tube through which water that absorbs latent heat is circulated is routed in the path of the exhausted combustion gas, the tube is accommodated inside the casing into which the combustion gas is introduced, and is introduced into the casing A heat exchanger characterized in that a rectifying plate for guiding the generated combustion gas along the corrugated piping of the tube is provided.   2. The heat exchanger according to claim 1, wherein the tube piping has a waveform in which the slope from the peak portion to the valley portion is parallel, and the rectifying plate is disposed in parallel with the tube.   The heat exchanger according to claim 1 or 2, wherein a clearance is provided between the rectifying plate and the bottom surface of the casing.   The heat exchanger according to any one of claims 1 to 3, wherein the rectifying plate is spot-attached to an upper portion of the casing.   The heat exchanger according to any one of claims 1 to 4, wherein the tube is formed by stacking a plurality of thin tubes vertically with a space between them, and a header for distributing and collecting water flowing through the interior is connected to the terminal. A heat exchanger characterized in that it is formed in a cylindrical shape with an axis perpendicular to the axis of this and is accommodated inside the casing.

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