JP4493799B2 - Catalyst-integrated heat exchanger for exhaust gas heat recovery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a catalyst-integrated heat exchanger for exhaust gas heat recovery in which a catalyst for purifying exhaust gas of a combustion apparatus such as an internal combustion engine and a heat exchanger for recovering heat of the exhaust gas are integrated. .
[0002]
[Prior art]
Conventionally, as this type of catalyst-integrated heat exchanger, for example, an exhaust gas purification of an engine and an exhaust gas heat recovery device disclosed in JP 2000-45764 A are known. In this apparatus, when the exhaust gas that has been purified by passing through the catalyst flows through the heat exchange chamber, the exhaust gas is mixed with cooling water that flows through a plurality of heat exchange pipes arranged in the heat exchange chamber at intervals in the circumferential direction. Heat exchange is performed between the two, and the heat of the exhaust gas is recovered in the cooling water.
[0003]
[Problems to be solved by the invention]
By the way, in this prior art, a plurality (24) of heat exchange pipes are supported by the upper end wall and the lower end wall of the heat exchanger body. At this time, in order to perform sufficient heat recovery, a large number of heat exchange pipes are required, the number of parts increases, the assembly man-hours increase, and it takes a lot of time to assemble the device. Productivity was not always good. In addition, when the heat exchange pipes are arranged in an annular shape as in the prior art, it is necessary to secure a space for the exhaust gas to circulate around each pipe, particularly in the radially inward and outward directions, As a result, the outer diameter of the heat exchanger was increased. Furthermore, since each heat exchange pipe is usually fixed to the upper end wall and the lower end wall by brazing or welding, there is a problem that the manufacturing cost increases due to brazing or welding, and brazing or The number of locations to be welded has increased, and this has led to a decrease in productivity.
[0004]
  Main departureAkira was made in view of these circumstances.And exhaustA common object of the catalyst-integrated heat exchanger for recovering heat of gas gas is to improve productivity and to make the heat exchanger compact, and the invention according to claim 2 further reduces the manufacturing cost. It aims to plan.
[0005]
  ContractThe invention described in claim 1 includes an inner case in which exhaust gas flows, and an outer case that surrounds the inner case and forms a fluid chamber in which a heat recovery fluid of exhaust gas heat flows between the inner case and the inner case. A combustion apparatus having a catalyst housed in the inner case, and a heat transfer section for exchanging heat between the exhaust gas that has passed through the catalyst and the heat recovery fluid in the fluid chamber, The exhaust gas passes through the catalyst and then passes through the heat transfer section, and then flows out of the inner case. Then, the heat transfer section is connected to the inner case. A cylindrical gas chamber formed using the cylindrical fluid chamber forming portion as an outer passage wall, and an intermediate tube disposed between the catalyst and the inner case as an inner passage wall, and a number of peaks and valleys A fin having a bent portion, and the fin includes the fluid The peaks and the valleys are disposed in the gas passage so as to respectively contact forming portions and said intermediate cylinderThe intermediate cylinder is provided with a catalyst accommodating cylinder having a bottom wall, and the catalyst is accommodated in the accommodating cylinder so that a first inversion chamber is formed between one end surface of the intermediate cylinder and the bottom wall. And an exhaust gas inflow pipe is provided through the central portion of the catalyst in the housing cylinder toward the bottom wall, whereby the exhaust gas flows from the upstream side to the downstream side in the inflow pipe. Exhaust gas reaching the end surface is reversed in the first reversing chamber so as to pass through the catalyst from the one end surface of the catalyst to the other end surface, and the inflow pipe passes through the storage tube, the intermediate tube, and the inner case. A lid body is fixed to the inner case so as to form a second reversing chamber in contact with the other end surface of the catalyst and from the other end surface of the catalyst. Exhaust gas flowing into the second reversing chamber flows into the heat transfer section in a reversing state. It is formed so as toA catalyst-integrated heat exchanger for recovering exhaust gas heat.
[0006]
According to the first aspect of the present invention, since the heat transfer area is increased by the fins arranged in the cylindrical gas passage, the heat of the exhaust gas purified by passing through the catalyst is obtained from the exhaust gas. When flowing through the passage, the heat recovery fluid is efficiently transmitted to the fluid chamber forming portion that forms the fluid chamber through which the heat recovery fluid flows, and is efficiently recovered into the heat recovery fluid. And since the fin is disposed between the fluid chamber forming portion and the intermediate cylinder, and the crest and trough thereof are in contact with the fluid chamber forming portion and the intermediate cylinder, respectively, the fluid chamber forming portion and Compared with the case where a heat exchange pipe is arranged between two members corresponding to the intermediate cylinders and a gap needs to be secured between the members in the radially inward and outward directions of the heat exchange pipe. The gap between the chamber forming portion and the intermediate cylinder may be small.
[0007]
As a result, a large heat transfer area of the fins arranged in the gas passage ensures a high heat exchange rate, and the gap between the fluid chamber forming portion where the fins are arranged and the intermediate cylinder can be kept small. Thus, an increase in the outer diameter of the heat exchanger is suppressed, and the heat exchanger can be made compact.
[0008]
According to a second aspect of the present invention, in the catalyst-integrated heat exchanger for exhaust gas heat recovery according to the first aspect, the fin is press-fitted between the fluid chamber forming portion and the intermediate cylinder. .
[0009]
According to the second aspect of the present invention, since the fin is fixed by being press-fitted between the outer passage wall and the intermediate cylinder, brazing and welding are not required, and assembly is also relatively short. That's okay.
[0010]
As a result, the following effects are exhibited. In other words, since the fins are fixed by press fitting, brazing and welding locations are reduced, so that the manufacturing cost of the heat exchanger can be reduced, and the assembly time of the heat exchanger is further reduced, so that productivity Will improve.
[0011]
According to a third aspect of the present invention, in the catalyst-integrated heat exchanger for exhaust gas heat recovery according to the first aspect, at least one of the inner case and the outer case includes a cylindrical case body having both ends open. And a lid of the same specification fixed to each of the both ends, and the lid is provided with a hole to which an inflow pipe or an outflow pipe for exhaust gas or heat recovery fluid is connected.
[0012]
  According to the third aspect of the present invention, the lid of the inner case or the outer case can share the same specification, and the inflow pipe or the outflow pipe is connected to the shared lid. Since it is provided, it is not necessary to provide holes for the inflow pipe and the outflow pipe separately.
  As a result, in addition to the effects of the invention described in claim 1 or claim 2, since the lid is shared, it is possible to reduce the number of types of devices for forming the lid, thereby reducing the manufacturing cost. Since the holes for the inflow pipe and the outflow pipe can also be shared, only the lid that is not provided with these holes is shared, and the hole machining process is reduced compared to the case where these holes are provided individually. Simplified and effective in improving productivity.
[0013]
  The invention according to claim 44. The catalyst-integrated heat exchanger for exhaust gas heat recovery according to claim 1, wherein the exhaust gas from the second inversion chamber flows between the catalyst housing cylinder and the intermediate cylinder. In addition, a heat insulating layer having a minute gap is formed.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to FIGS.
In FIG. 1, a catalyst-integrated heat exchanger 1 for exhaust gas heat recovery, which is an embodiment of the present invention, is exhausted from an internal combustion engine as a combustion device used to drive a generator, a pump, and the like. An inner case 2 having lids at both ends so as to form an exhaust gas chamber 4 through which exhaust gas flows, and an inner case 2 that is disposed substantially concentrically are disposed in an exhaust system through which gas flows. And an outer case 3 having lids at both ends. A gap is formed between the inner case 2 and the outer case 3, and a space formed by the gap is a fluid chamber 5 in which a heat recovery fluid that recovers the heat of the exhaust gas, for example, cooling water of the internal combustion engine flows. Form.
[0015]
The inner case 2 is hermetically fixed by welding or the like to a metal case, for example, a stainless steel cylindrical case body 6 with an inflow side end portion 6a and an outflow side end portion 6b open, and both ends 6a and 6b. Inflow side lid body 7 and outflow side lid body 8. The central axis L of the cylindrical case body 6 is the central axis L of the heat exchanger 1. The inflow side cover body 7 is substantially concentric with the case body 6 to which an inflow pipe 9 made of metal, for example, stainless steel, for introducing the exhaust gas discharged from the internal combustion engine is hermetically connected and fixed to the inner case 2. A mounting body 7a at the center thereof, and the outflow side cover 8 has a case main body in which an outflow pipe 10 for exhausting exhaust gas after being purified and heat exchanged is hermetically connected and fixed. 6 has a mounting hole 8a substantially concentric with the central portion thereof. Here, the inflow side lid body 7 and the outflow side lid body 8 are formed to have the same specifications, that is, the same shape, structure, dimensions, and the like by pressing a metal plate, for example, a stainless steel plate. The lid bodies 7 and 8 have mounting holes 7a and 8a and projections 7c and 8c, which will be described later, and outer peripheral edge portions 7b and 8b extending in the axial direction on the outer peripheral surfaces of both end portions 6a and 6b of the case body 6. It is a substantially disk-shaped member that constitutes a fitting portion that is fitted and fixed by welding or the like.
[0016]
2 and 3 together, the outer case 3 has a larger inner diameter than the inner case 2 so as to form a radial gap between the inner case 2 and the case main body 6, and the case main body. A cylindrical case body 11 made of a metal, for example, stainless steel, having an inflow end 11a and an outflow end 11b that are longer in the axial direction than 6, and welded to both ends 11a and 11b, respectively. An inflow side lid body 12 and an outflow side lid body 13 that are liquid-tightly fixed by, for example. The inflow side cover body 12 has a mounting hole 12a at a position eccentric from the central axis L, to which an inflow pipe 14 for introducing a heat recovery fluid into the heat exchanger 1 is connected and fixed in a liquid-tight manner. The outflow side cover body 13 has a mounting hole 13a at a position eccentric from the central axis L, to which an outflow pipe 15 for discharging the heat recovery fluid after heat exchange is connected and fixed in a liquid-tight manner. Here, the inflow side lid body 12 and the outflow side lid body 13 are formed to have the same specifications, that is, the same shape, structure, dimensions, and the like by pressing a metal plate, for example, a stainless steel plate. The lid bodies 12 and 13 have mounting holes 12a and 13a, and outer peripheral edge portions 12b and 13b extending in the axial direction are fitted to the outer peripheral surfaces of both end portions 11a and 11b of the case main body 11 by welding or the like. A fixed fitting portion is formed, and the inner peripheral edge portions 12c and 13c are joined to the outer surface of the inflow side lid body 7 or the outflow side lid body 8 substantially concentrically with the mounting holes 7a and 8a and fixed in a liquid-tight manner. It is the substantially annular member which comprises a part. In this embodiment, the inflow pipe 14 and the outflow pipe 15 are also composed of members having the same specifications.
[0017]
The fluid chamber 5 includes an annular first fluid chamber 5a formed mainly between the inflow side lid body 12 and the outflow side lid body 8, and a cylinder formed mainly between the case body 6 and the case body 11. And the annular third fluid chamber 5c formed mainly between the outflow side lid body 13 and the inflow side lid body 7. The second fluid chamber 5b is formed of a spiral passage, and the spiral passage 16 includes a spiral tube 16 fixed in contact with the outer peripheral surface of the case body 6 and the inner peripheral surface of the case body 11. And the case main body 11 are formed by extending in a spiral manner.
[0018]
The first and third fluid chambers 5a and 5c are formed of an annular passage substantially concentric with the central axis L, the inflow pipe 14 is opened in the first fluid chamber 5a, and the outflow pipe 15 is formed in the third fluid chamber 5c. It is open. The lid bodies 12 and 13 are respectively provided at both end portions 11a and 11b of the case body 11 so that the mounting holes 12a and 13a occupy positions in the diameter direction of the lid bodies 12 and 13 when viewed from the axial direction. The inflow pipe 14 is fixed at the substantially same circumferential position as the upstream end 16a of the spiral pipe 16, and the outflow pipe 15 is located at the same circumferential position as the downstream end 16b of the spiral pipe 16.
[0019]
  On the other hand, inside the inner case 2 that forms the exhaust gas chamber 4, a catalyst 17 that is formed in a cylindrical shape and its accommodating cylinder 18 are arranged and accommodated substantially concentrically with the inner case 2. The catalyst 17 is a catalyst 17 that is known per se to purify exhaust gas by detoxifying harmful components such as HC and CO contained in the exhaust gas, and includes an upstream end 18a and a downstream end 18b. Is inserted in an airtight manner into a metal-made, for example, stainless-steel, cylindrical housing cylinder 18 and accommodated. An inflow pipe 9 is hermetically inserted into a center hole 17c formed of a through hole provided substantially concentrically with the accommodating cylinder 18 inside the catalyst 17, and an upstream end 9a located upstream with respect to the flow of exhaust gas. Is positioned on the outside of the inner case 2 through the inflow side lid 7 and is press-fitted into a connection flange 19 for connecting the exhaust pipe of the internal combustion engine and the heat exchanger 1. Reference numeral 19a denotes four screw holes for fastening bolts (see FIG. 2). Further, the downstream end 9b of the inflow pipe 9 is an upstream end surface located upstream of the exhaust gas flow in the catalyst 17.17aAnd be made to be almost flush with each other. Therefore, in the catalyst 17, the upstream end surface 17a and the downstream end surface 17b serve as an exhaust gas inlet and an outlet, respectively.
[0020]
The upstream end portion 18a of the housing cylinder 18 extends a predetermined length in the axial direction from the upstream end surface 17a of the catalyst 17, and is closed by a bottom wall 20 made of a disk that is airtightly fixed to the upstream end portion 18a. . Then, between the upstream end face 17a of the catalyst 17 and the bottom wall 20, the exhaust gas flowing in from the inflow pipe 9 goes radially outward, and then reverses to flow toward the upstream end face 17a of the catalyst 17. A first inversion chamber 21 is formed. Therefore, the inflow pipe 9 is open at the center of the first inversion chamber 21. The downstream end portion 18b of the storage cylinder 18 is open toward the inflow side lid body 7, and is substantially flush with the downstream end surface 17b of the catalyst 17.
[0021]
Further, in the inner case 2, a radial gap between the housing cylinder 18 and the case body 6 is substantially concentric with the housing cylinder 18 (a radial direction between the case body 6 and the intermediate cylinder 22 described later). The cylindrical intermediate tube 22 made of metal, for example, stainless steel, is accommodated through a predetermined gap (about 1/5 of the predetermined gap). The downstream end 22b of the intermediate cylinder 22 having an axial length longer than the housing cylinder 18 extends a predetermined length in the axial direction from the upstream end 18a of the housing cylinder 18, and the downstream end 22b A perforated bottom wall 23 made of a disk provided with a small hole 23a substantially concentric with the intermediate cylinder 22 is fixed in an airtight manner. Therefore, a first collecting chamber 25 is formed between the bottom wall 20 and the perforated bottom wall 23 in which the exhaust gas flowing in from the heat insulating layer 24 formed from the cylindrical space formed by the minute gaps gathers. The The small holes 23a disposed substantially concentrically with respect to the outflow pipe 10 allow exhaust gas to flow out from the first collecting chamber 25 and are arranged so that the central axis L is directed in the vertical direction. Is disposed in the lower part of the heat exchanger 1, it also functions as a drain hole for discharging moisture in the exhaust gas condensed into a liquid from the first collecting chamber 25. Further, the upstream end 22 a of the intermediate cylinder 22 is open toward the inflow side lid 7 and is substantially flush with the downstream end surface 17 b of the catalyst 17.
[0022]
Further, the case body 6 extends a predetermined length in the axial direction from the downstream end face 17b of the catalyst 17, the downstream end 18b of the housing cylinder 18 and the upstream end 22a of the intermediate cylinder 22, and is downstream of the intermediate cylinder 22. It extends in the axial direction from the side end 22b. Then, the downstream end surface 17 b of the catalyst 17, the downstream end portion 18 b of the housing cylinder 18, the upstream end portion 22 a of the intermediate cylinder 22, and the inflow side lid body 7 flow from the downstream end surface 17 b of the catalyst 17. The direction of the flow of the exhaust gas after purification is reversed, and the second reversing chamber 26 in which the flow toward the upstream opening 24a of the heat retaining layer 24 and the upstream opening 29a of the gas passage 29 of the heat transfer section 28 described later is generated. It is formed. Therefore, of the high-temperature exhaust gas immediately after passing through the catalyst 17, a small amount that is sufficient to keep the catalyst 17 warm flows into the heat retaining layer 24, and all the rest flows into the gas passage 29. Further, a second collecting chamber 27 is formed between the perforated bottom wall 23 and the outflow side lid 8, in which exhaust gas after heat exchange that has flowed in from the downstream end opening 29 b of the gas passage 29 gathers. The outflow pipe 10 opens into the collecting chamber 27.
[0023]
On the other hand, the heat transfer portion 28 that is disposed between the catalyst 17 and the fluid chamber 5 and performs heat exchange between the purified exhaust gas and the heat recovery fluid is also a fluid chamber 5 forming portion in the inner case 2. The case body 6 includes a cylindrical gas passage 29 formed with the outer passage wall as an outer passage wall and the intermediate tube 22 as an inner passage wall, and a bellows-like fin 30 described later.
[0024]
As shown in FIGS. 4 and 5, the fin 30 has a large number of crests 30c and troughs 30d formed by bending a single metal thin plate made of, for example, stainless steel alternately. The intermediate cylinder 22 has substantially the same axial length, the crests 30c are in contact with the inner peripheral surface of the case body 6 and the troughs 30d are in contact with the outer peripheral surface of the intermediate cylinder 22 in the radial direction. The case body 6 and the intermediate cylinder 22 which are arranged with a predetermined gap are press-fitted in a radially pressed state over the entire circumference. The generally cylindrical gas passage 29 formed between the case body 6 and the intermediate cylinder 22 is divided by the fins 30 into a large number of small gas passages 29c extending in the axial direction in the circumferential direction. In assembling the heat exchanger 1, the case main body 6 forming the gas passage 29 and the intermediate cylinder 22 are press-fitted between them, and the upstream end 30a and the downstream end 30b are connected to the intermediate cylinder. The fins 30 that are substantially flush with the upstream end 22a and the downstream end 22b of 22 are assembled in advance so as to form one unit.
[0025]
Further, as shown in FIGS. 1 to 3, the inflow side lid body 7 and the outflow side lid body 8 have three projections 7 c and 8 c that project in the axial direction toward the inside of the inner case 2. It is provided at equal intervals in the circumferential direction on the same circumference. In the inflow side lid body 7, the three protrusions 7 c abut on the downstream end surface 17 b of the catalyst 17, so that the axial dimension of the second reversing chamber 26 becomes a predesigned value. In addition, the positioning of the catalyst 17 in the axial direction with respect to the inner case 2 is facilitated, and the concentricity between the housing cylinder 18 and the inner casing 2 and the intermediate cylinder 22 disposed through the minute gap can be obtained reliably and easily. I am doing so. Further, in the outflow side lid 8, the three projections 8c abut against the perforated bottom wall 23 so that the axial dimension of the second collecting chamber 27 is the same as that of the second inversion chamber 26. Thus, the fluidity of the exhaust gas in the second reversing chamber 26 and the second collecting chamber 27 is made substantially equal, and the axial positioning of the intermediate cylinder 22 with respect to the inner case 2 is facilitated.
[0026]
Next, the operation of this embodiment will be described.
Exhaust gas discharged from an internal combustion engine (not shown) flows through the inflow pipe 9 in the direction of arrow A while heating the catalyst 17 at the portion inserted into the catalyst 17 and flows into the center of the first reversing chamber 21, The direction of the flow is changed when it hits 20 and flows almost uniformly outward in the radial direction, and then is reversed and flows into the catalyst 17 to be purified. The purified exhaust gas flows into the second reversing chamber 26 from the catalyst 17, hits the inflow side cover body 7, changes its flow direction, flows substantially uniformly outward in the radial direction, and then is reversed and a small amount thereof. Flows into the heat insulating layer 24.
[0027]
A small amount of exhaust gas that has flowed into the heat insulating layer 24 flows between the accommodating cylinder 18 and the intermediate cylinder 22 in the axial direction and flows out from the small holes 23a.Therefore, a flow of exhaust gas always exists in the heat insulating layer 24, Hot exhaust gas immediately after passing through the catalyst 17 efficiently flows into the heat retaining layer 24. Therefore, although the intermediate cylinder 22 constituting the heat transfer section 28 that exchanges heat with the heat recovery fluid is relatively low in temperature, the high temperature exhaust gas is always supplied to the heat retaining layer 24, and the exhaust gas in the heat retaining layer 24 is Since the gas is smoothly switched, the exhaust gas existing in the heat insulating layer 24 is hardly affected by the low temperature, the heat insulating layer 24 is maintained at a high temperature, and the catalyst 17 is also maintained in a high temperature state with a high purification rate.
[0028]
  All remaining in second reversal chamber 26ofThe exhaust gas flows into the gas passages 29 of the heat transfer section 28 and flows in the axial direction through many small gas passages 29c. Since the heat transfer area is enlarged by the fins 30 arranged all around the inside of the gas passage 29, the exhaust gas flows through the gas passage 29 as the heat of the hot exhaust gas immediately after passing through the catalyst 17 In doing so, the heat is efficiently transferred to the case body 6 that forms the fluid chamber 5 through which the heat recovery fluid flows, through the fins 30, and heat exchange is performed at a high heat exchange rate.
[0029]
The low-temperature exhaust gas after heat exchange with the heat recovery fluid via the case body 6 flows into the second collecting chamber 27 from the outer peripheral side, and the flow direction is changed radially inward to the central portion. On the other hand, it flows through the outflow pipe 10 in the direction of arrow B and flows out of the heat exchanger 1.
[0030]
On the other hand, the heat recovery fluid flows in the inflow pipe 9 in the direction of arrow C, flows into the first fluid chamber 5a, exchanges heat with the exhaust gas in the second collecting chamber 27 via the outflow side lid 8, Recover exhaust gas heat. Thereafter, the heat recovery fluid flows through the second fluid chamber 5b formed of a spirally elongated passage, exchanges heat with the exhaust gas flowing through the heat transfer section 28, and recovers the heat of the exhaust gas. Furthermore, the heat recovery fluid that has flowed into the third fluid chamber 5c through the second fluid chamber 5b exchanges heat with the exhaust gas in the second reversing chamber 26 via the inflow side lid body 7, and then heats the exhaust gas. After the recovery, it flows through the outflow pipe 15 in the direction of arrow D, finishes the heat recovery in the heat exchanger 1, and flows out to the outside.
[0031]
Since this embodiment is configured as described above, the following effects can be obtained.
A large heat transfer area is secured by the fins 30 arranged on the entire circumference of the gas passage 29, and a high heat exchange rate is obtained. Further, since the high-temperature exhaust gas immediately after passing through the catalyst 17 flows into the heat transfer section 28, the heat transfer section 28 can recover the heat of the exhaust gas with a high heat exchange rate.
[0032]
Since the fin 30 is disposed between the case main body 6 and the intermediate cylinder 22, and the crest 30c and the trough 30d are in contact with the case main body 6 and the intermediate cylinder 22, respectively. Compared with the one in which the heat exchange pipe is arranged between two members corresponding to the intermediate cylinder 22 and it is necessary to secure a gap between the members in the radial direction inside and outside of the heat exchange pipe, The radial gap between the case body 6 and the intermediate cylinder 22 can be small. Therefore, a high heat exchange rate is ensured by the large heat transfer area of the fins 30, and the radial gap between the case body 6 and the intermediate cylinder 22 where the fins 30 are disposed can be kept small. Thus, an increase in the outer diameter of the heat exchanger 1 is suppressed, and the heat exchanger 1 can be made compact.
[0033]
Since the fin 30 is fixed by being press-fitted between the case body 6 and the intermediate cylinder 22, brazing and welding are not required, and assembly is also relatively short. As a result, since the fins 30 are fixed by press fitting, brazing and welding locations are reduced, so that the manufacturing cost of the heat exchanger 1 can be reduced, and the assembly time of the heat exchanger 1 is further shortened. Therefore, productivity is improved.
[0034]
Further, since the fin 30 is formed from a single thin plate, the number of parts can be reduced and the number of assembling steps can be reduced. Further, the case body 6, the intermediate tube 22, and the fin 30 are made into one unit in advance. Therefore, the assemblability is improved and the productivity of the heat exchanger 1 can be improved.
[0035]
The lids 7 and 8 of the inner case 2 can share the same specifications, and the lids 12 and 13 of the outer case 3 can also share the same specifications, so the lids 7, 8, 12 , 13 can be reduced in the number of types of press working apparatuses, which can contribute to the reduction of manufacturing costs. Moreover, since the shared lids 7, 8, 12, 13 are also provided with mounting holes 7a, 8a, 12a, 13a to which the inflow pipes 9, 14 or the outflow pipes 10, 15 are connected, for inflow pipes and outflow pipes. There is no need to provide individual holes, and only the lid that is not provided with these mounting holes is shared. Compared to the case where these mounting holes are provided individually, the mounting hole processing process is simplified and production is performed. It can contribute to the improvement of sex. In addition, since the inflow pipe 14 and the outflow pipe 15 can be shared, this point can also contribute to the reduction of the manufacturing cost.
[0036]
Since the exhaust gas in the heat retaining layer 24 is smoothly replaced, the heat retaining layer 24 maintains a high temperature state in which the catalyst 17 functions at a high purification rate, and the purification performance of the catalyst 17 can be maintained or improved. Further, since the inflow pipe 9 is inserted into the center hole 17c of the catalyst 17 and the heat insulating layer 24 is provided, the time from the start of the internal combustion engine to the activation of the catalyst 17 is shortened. Performance can be improved.
[0037]
The exhaust gas from the inflow pipe 9 flows almost uniformly radially outward in the first reversing chamber 21 and flows into the catalyst 17, and flows substantially uniformly radially outward in the second reversing chamber 26. After passing through 28, it flows radially inward in the second collecting chamber 27, travels toward the center, and flows out of the heat exchanger 1 from the outflow pipe 10. Therefore, the exhaust gas flows evenly and smoothly throughout the inner case 2. As described above, since the exhaust gas flow in the inner case 2 and the outflow from the outflow pipe 10 are smooth, the heat transfer from the heat transfer section 28, the inflow side, and the outflow side lids 7 and 8 also in this respect. It can contribute to the improvement of the heat exchange rate.
[0038]
Further, the exhaust gas flows into the first reversing chamber 21 from the downstream end 9b of the inflow pipe 9 inserted into the center hole 17c of the catalyst 17, and flows in the first reversing chamber 21 substantially uniformly in the radial direction. In order to allow the exhaust gas to flow uniformly into the large-diameter catalyst from the small-diameter inflow pipe, which is necessary when the exhaust gas flows into the catalyst without being reversed, Therefore, the axial dimension from the upstream end 9a of the inflow pipe 9 to the upstream end surface 17a, which is the end surface opposite to the upstream end 9a, of the catalyst 17 is eliminated. Can be shortened, the axial length of the heat exchanger 1 can be shortened, and a compact heat exchanger 1 can be obtained.
[0039]
In addition, although the axial length of the heat exchanger 1 is short, the heat recovery fluid passes through the outflow side cover 8 and the inflow side cover 7 in the first and third fluid chambers 5a and 5c, respectively. In addition to all the heat recovery, the heat of the exhaust gas can be effectively recovered through heat recovery through the case body 6 of the heat transfer section 28 in the second fluid chamber 5b formed of a spirally elongated passage. Can do.
[0040]
Since the three protrusions 7c of the inflow side lid body 7 are in contact with the downstream end face of the catalyst 17, the axial dimension of the second reversing chamber 26 can be easily set to a set value, Positioning of the catalyst 17 in the axial direction with respect to the inner case 2 can be easily performed, and concentricity between the housing cylinder 18 and the inner case 2 and the intermediate cylinder 22 can be reliably and easily obtained. Further, since the three protrusions 8c of the outflow side cover 8 are in contact with the perforated bottom wall 23, the axial dimension of the second collecting chamber 27 is the same as that of the second reversing chamber 26. Thus, the fluidity of the exhaust gas in the second reversing chamber 26 and the second collecting chamber 27 can be made substantially equal, and the intermediate cylinder 22 can be easily positioned in the axial direction with respect to the inner case 2.
[0041]
Hereinafter, an example in which a part of the configuration of the above-described embodiment is changed will be described with respect to the changed configuration.
In the above-described embodiment, the inflow side lids 7 and 12 and the outflow side lids 8 and 13 of the inner case 2 and the outer case 3 are shared, but the inflow of either the inner case 2 or the outer case 3 is used. The side lid bodies 7 and 12 and the outflow side lid bodies 8 and 13 may be shared. Moreover, each case main body 6,11, the intermediate | middle cylinder 22, and the accommodating cylinder 18 may be cylindrical members other than a cylindrical shape.
[0042]
In the embodiment, the fin 30 is fixed by being press-fitted between the case main body 6 and the intermediate cylinder 22, but the fin can be fixed by brazing. Even in this case, the sheet-like brazing material is put in the furnace and heated while being sandwiched between the fin 30 and the case body 6 and between the fin 30 and the intermediate cylinder 22. Thus, since the fin 30 can be easily fixed to the case body 6 and the intermediate cylinder 22, the number of assembling steps can be reduced as compared with the conventional technique using the heat exchange pipe, and the productivity is improved.
[0043]
Further, in the above embodiment, the fin 30 is formed from one thin plate, but the fin 30 disposed in the gas passage 29 is replaced with the fin formed from one thin plate as the exhaust gas in the gas passage 29. A plurality of, for example, two or three, for example, may be arranged in series with respect to the flow. Also in this case, the number of parts is reduced as compared with the prior art using the heat exchange pipe, the number of assembling steps is reduced, and the productivity is improved.
[0044]
In addition to the internal combustion engine, the combustion apparatus may be any apparatus that performs combustion, such as a boiler. In that case, the heat recovery fluid may be simple water for hot water supply or the like. Further, a gas such as air may be used. Further, the number of projections 7c and 8c formed on both lids 7 and 8 is three, but may be four or more.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a catalyst-integrated heat exchanger for exhaust gas heat recovery according to an embodiment of the present invention, and is a sectional view taken along line II in FIG.
FIG. 2 is a view taken in the direction of arrow II in FIG.
FIG. 3 is a view taken in the direction of arrow III in FIG.
4 is a cross-sectional view taken along line IV-IV in FIG.
FIG. 5 is a partially enlarged view of FIG. 4;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Heat exchanger, 2 ... Inner case, 3 ... Outer case, 4 ... Exhaust gas chamber, 5 ... Fluid chamber, 6 ... Case main body, 7 ... Inflow side cover body, 7a ... Mounting hole, 8 ... Outflow side cover body 8a ... mounting hole, 9 ... inflow pipe, 10 ... outflow pipe, 11 ... case body, 12 ... inflow side lid, 13 ... outflow side lid, 14 ... inflow pipe, 15 ... outflow pipe, 16 ... spiral pipe, 17 ... Catalyst, 18 ... Housing cylinder, 19 ... Connection flange, 20 ... Bottom wall, 21 ... First reversing chamber, 22 ... Intermediate cylinder, 23 ... Perforated bottom wall, 23a ... Small hole, 24 ... Thermal insulation layer, 25 ... 1st collective chamber, 26 ... 2nd reversing chamber, 27 ... 2nd collective chamber, 28 ... heat transfer part, 29 ... gas passage, 30 ... fin, 30c ... mountain part, 30d ... valley part,
L: Center axis.

Claims (4)

An inner case through which exhaust gas flows, an outer case that surrounds the inner case and forms a fluid chamber through which heat recovery fluid of exhaust gas heat flows between the inner case, and the inner case are housed in the inner case A catalyst, and a heat transfer section that exchanges heat between the exhaust gas that has passed through the catalyst and the heat recovery fluid in the fluid chamber, and the exhaust gas of the combustion device that has flowed into the inner case passes through the catalyst Then, after passing through the heat transfer section, in the catalyst-integrated heat exchanger for recovering heat of exhaust gas flowing out from the inner case,
The heat transfer section is a cylindrical gas formed with a cylindrical fluid chamber forming portion of the inner case as an outer passage wall and an intermediate tube disposed between the catalyst and the inner case as an inner passage wall. A plurality of crests and troughs bent to form the gas passages so that the crests and troughs are in contact with the fluid chamber forming portion and the intermediate cylinder, respectively. It is located within,
A catalyst housing cylinder having a bottom wall is provided in the intermediate cylinder, and the catalyst is accommodated in the housing cylinder so that a first inversion chamber is formed between one end surface of the intermediate cylinder and the bottom wall. An exhaust gas inflow pipe is provided through the central portion of the catalyst in the housing cylinder toward the bottom wall, whereby the end face of the catalyst flows through the inflow pipe from the upstream side to the downstream side. The exhaust gas reaching to is reversed in the first reversing chamber so as to pass from the one end surface of the catalyst to the other end surface through the catalyst,
The lid is fixed to the inner case so as to cover the housing cylinder, the intermediate cylinder and the inner case from the upstream side of the inflow pipe and to form a second reversing chamber in contact with the other end surface of the catalyst. The lid body is formed such that exhaust gas flowing into the second reversal chamber from the other end surface of the catalyst flows into the heat transfer section in a reversed state. Catalyst-integrated heat exchanger for recovery.   The catalyst-integrated heat exchanger for exhaust gas heat recovery according to claim 1, wherein the fin is press-fitted between the fluid chamber forming portion and the intermediate cylinder.   At least one of the inner case and the outer case includes a cylindrical case body having both ends opened, and lids of the same specification that are respectively fixed to the both ends. 3. A catalyst-integrated heat exchanger for exhaust gas heat recovery according to claim 1, wherein a hole to which an inflow pipe or an outflow pipe for heat recovery fluid is connected is provided. 4. A heat insulating layer having a minute gap is formed between the catalyst housing cylinder and the intermediate cylinder so that exhaust gas from the second inversion chamber flows. A catalyst-integrated heat exchanger for exhaust gas heat recovery according to claim 1.

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