JP7265962B2 - plate heat exchanger - Google Patents

Description

The present invention is a plate-type unit comprising a plurality of blocks each having a heat exchange body that exchanges heat between a first fluid circulating inside and a second fluid circulating outside, wherein the plurality of blocks are stacked. It relates to heat exchangers.

Conventionally, there has been proposed a plate heat exchanger provided with a plurality of heat exchange elements in which an upper heat exchange plate and a lower heat exchange plate are joined (for example, Patent Literature 1). Each heat exchange element has an internal space between the upper heat exchange plate and the lower heat exchange plate in which a heat medium, which is a first fluid, flows, and a combustion exhaust gas, which is a second fluid. has a plurality of through-holes through which it flows vertically.

The plate heat exchanger is constructed by vertically stacking a plurality of blocks each having at least one heat exchange body. Blocks adjacent in the vertical direction are communicated with each other so that the heat medium flows. Further, the adjacent blocks are configured such that the flow direction of the heat medium flowing through one block is different from that of the heat medium flowing through the other block. As a result, the flow path of the heat medium flowing through the heat exchanger becomes longer according to the number of stages of the blocks, and the heat efficiency can be improved.

Korean Patent No. 10-1608149

By the way, in a plate-type heat exchanger in which a plurality of heat exchange bodies are stacked, the projected surface of the through hole of one heat exchange body overlaps with the through hole of the other heat exchange body when viewed from the direction of the combustion exhaust flow path. If the adjacent heat exchangers are formed so as not to cause the heat exchangers to be separated from each other, the gas flow paths of the combustion exhaust gas in the heat exchangers are lengthened, and the thermal efficiency can be improved.

However, in the heat exchanger having the arrangement structure of the through-holes as described above, the through-holes of the upstream heat-exchanging body face the projected surface where the through-holes of the downstream-side heat exchanging body are not formed. Therefore, the combustion exhaust that has flowed through the through holes of the heat exchange body on the upstream side first collides with the projection surface on one side of the heat exchange body on the downstream side, and then spreads on the one side of the heat exchange body on the downstream side. , and further flows downstream from the through-holes of the heat exchange body on the downstream side. Therefore, in the upstream region of the combustion exhaust gas flow path through which the high-temperature combustion exhaust flows, the portion of the downstream heat exchange element facing the through-hole of the upstream heat exchange element is concentratedly heated, and local heat is generated. There is a problem that arises. In particular, the downstream heat exchange element adjacent to the most upstream heat exchange element in the combustion exhaust gas flow path does not exchange heat with the heat medium flowing inside the most upstream heat exchange element. Since high-temperature exhaust gas flowing through the through-holes of the heat exchange body collides with each other, the problem of local heat is likely to occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to prevent local heating of a heat exchanging body adjacent to the downstream side of the most upstream heat exchanging body in the flow path of the second fluid. to do.

According to the invention,
A plate heat exchanger comprising a plurality of blocks each having a heat exchange body for exchanging heat between a first fluid circulating inside and a second fluid circulating outside, wherein the plurality of blocks are stacked. and
The heat exchange body has a plurality of through holes formed so that the second fluid flows outside the heat exchange body in a direction intersecting with a flow path surface of the first fluid flowing inside the heat exchange body. has
Adjacent heat exchange bodies are formed so that the projected surface of the through hole of one heat exchange body does not overlap the through hole of the other heat exchange body when viewed from the flow path direction of the second fluid,
each block has an inlet for introducing the first fluid into each block and an outlet for introducing the first fluid to the outside of each block;
In the adjacent blocks, the flow direction of the first fluid flowing through the heat exchanging bodies constituting one block is the first fluid flowing through the heat exchanging bodies constituting the other block. formed differently from that of a fluid,
A communication passage is formed between the adjacent blocks to communicate the outlet port of the one block and the inlet port of the other block,
Among the plurality of blocks, the most upstream block positioned most upstream in the flow path of the second fluid is configured by stacking at least two or more heat exchange bodies,
The two or more heat exchange bodies constituting the most upstream block are formed so that the first fluid flows in parallel inside the two or more heat exchange bodies,
Among the two or more heat exchange bodies constituting the most upstream block, the most upstream heat exchange body positioned most upstream in the flow path of the second fluid, and the second most upstream heat exchange body The second heat exchange body adjacent to the downstream side of the flow path of the fluid is the flow rate of the first fluid flowing inside the second heat exchange body, the flow rate of the first fluid flowing inside the most upstream heat exchange body A plate heat exchanger is provided that is configured to be more than that of the first fluid.

According to the above heat exchanger, the two or more heat exchange bodies that constitute the most upstream block are formed so that the first fluid flows in parallel inside the two or more heat exchange bodies, and the most upstream heat exchange The body and the second heat exchange body are such that the flow rate of the first fluid flowing inside the second heat exchange body collides with the second fluid flowing through the through holes of the most upstream heat exchange body Since the second fluid passing through the through-holes of the most upstream heat exchanger is concentrated on the projection plane of the second heat exchanger, the second fluid is more concentrated than the first fluid flowing inside. However, local overheating of the second heat exchange body can be prevented.

Preferably, in the heat exchanger,
The most upstream block is configured by stacking three or more heat exchange bodies,
The three or more heat exchange elements constituting the most upstream block are configured such that the flow rate of the first fluid flowing inside the second heat exchange element is maximized.

According to the above heat exchanger, among the three or more heat exchange bodies constituting the most upstream block, the first fluid is circulated inside the second heat exchange body at the maximum flow rate, so Local overheating of the second heat exchanger can be prevented even if the second fluid that has passed through the holes concentrates on a small projected surface of the second heat exchanger.

Preferably, in the heat exchanger,
throttling means for throttling the flow rate of the first fluid flowing through the most upstream heat exchange body to at least one of an inflow side flow path and an outflow side flow path of the first fluid in the most upstream heat exchange body; is formed.

According to the above heat exchanger, since the first fluid flows in parallel inside the uppermost heat exchange body and the second heat exchange body, By forming a throttling means for throttling the flow rate of the first fluid in at least one of the passages, the flow rate of the first fluid circulating inside the second heat exchange element is circulated inside the most upstream heat exchange element. It can be more than that of the first fluid. Further, according to the above heat exchanger, it is possible to suppress fluctuations in the flow path resistance of the first fluid when the first fluid flows through the intermediate portion inside the most upstream heat exchanger. Thereby, the unevenness of the temperature of the most upstream heat exchange element heated by the second fluid can be reduced.

Preferably, in the heat exchanger,
a lead-out pipe is inserted from the most downstream heat exchange element located most downstream in the flow path of the second fluid to the most upstream heat exchange element,
The outlet pipe is configured such that the first fluid flows out from the most upstream heat exchanger and the second heat exchanger into the outlet pipe,
The outflow pipe allows the first fluid to flow out from the most upstream heat exchanging element to the outflow pipe so that the first fluid flows out from the second heat exchanging element to the outflow pipe. is formed to be narrower.

According to the above heat exchanger, the first fluid flows out in parallel from the most upstream heat exchanger and the second heat exchanger that constitute the most upstream block to the lead-out pipe. In addition, the outflow-side channel through which the first fluid flows out from the most upstream heat exchanging element to the outlet pipe is formed to be narrower than that through which the first fluid flows out from the second heat exchanging element to the outlet pipe. , the flow resistance of the first fluid flowing inside the most upstream heat exchanging body can be made higher than that of the first fluid flowing inside the second heat exchanging body. Thereby, the flow rate of the first fluid flowing inside the second heat exchanging body can be made larger than that of the first fluid flowing inside the most upstream heat exchanging body. In addition, according to the above heat exchanger, since the outflow-side passage through which the first fluid flows out from the most upstream heat exchanging element to the outlet tube is narrowed, the first fluid flowing through the most upstream heat exchanging element The channel resistance of the first fluid can be increased on the most downstream side of the channel. As a result, even when the flow rate of the first fluid supplied into the heat exchanger is small, the first fluid can be smoothly circulated inside the most upstream heat exchanger, and local overheating in the most upstream heat exchanger can be prevented. can be prevented. In addition, since the outlet pipe can reduce the flow rate of the first fluid flowing inside the most upstream heat exchanger, it is not necessary to manufacture dedicated heat exchangers as the most upstream heat exchanger and the second heat exchanger. do not have. Thereby, cost can be reduced.

As described above, according to the present invention, more of the first fluid circulates in the second heat exchange element adjacent to the downstream side of the flow path of the second fluid in the most upstream heat exchange element than in the most upstream heat exchange element. do. Therefore, the plurality of heat exchange bodies are arranged so that the projected plane of the through hole of one heat exchange body does not overlap the through hole of the other adjacent heat exchange body when viewed from the direction of flow of the second fluid. Local heating of the second heat exchanger can be prevented in the stacked plate heat exchanger. As a result, boiling and denaturation of the first fluid flowing inside the second heat exchange body can be prevented, and deformation of the second heat exchange body can be prevented, thereby providing a heat exchanger having excellent durability. can be done.

FIG. 1 is a schematic partially cutaway perspective view showing a heat source equipment having a heat exchanger according to an embodiment of the present invention. FIG. 2 is a schematic partially exploded perspective view showing a heat exchanger according to an embodiment of the invention. FIG. 3 is a schematic enlarged cross-sectional view of the inflow pipe side showing the heat exchanger according to the embodiment of the present invention. FIG. 4 is a schematic enlarged cross-sectional view of the outflow pipe side of the heat exchanger according to the embodiment of the present invention. FIG. 5 is a schematic diagram illustrating flows of the first fluid and the second fluid in the heat exchanger according to the embodiment of the present invention. FIG. 6 is a schematic perspective view showing a lead-out tube according to an embodiment of the invention.

Hereinafter, a plate heat exchanger according to the present embodiment and a heat source device including the plate heat exchanger will be specifically described with reference to the accompanying drawings.

As shown in FIG. 1, the heat source equipment according to the present embodiment converts water (first fluid) flowing into the heat exchanger 1 from the inflow pipe 20 into combustion exhaust gas (second fluid) generated by the burner 31. , and supplies hot water to a hot water user (not shown) such as a faucet or shower through an outflow pipe 21 . Although not shown, the water heater is built into the casing. Note that another heat medium (for example, antifreeze) may be used as the first fluid.

In this water heater, a burner body 3 forming an outer shell of a burner 31, a combustion chamber 2, a heat exchanger 1, and a drain receiver 40 are arranged in order from above. A fan case 4 having a combustion fan for sending a mixed gas of fuel gas and air into the burner body 3 is arranged on one side (the right side in FIG. 1) of the burner body 3 . An exhaust duct 41 communicating with a drain receiver 40 is arranged on the other side (left side in FIG. 1) of the burner body 3 . The exhaust duct 41 discharges the combustion exhaust discharged to the drain receiver 40 to the outside of the water heater.

In this specification, when the water heater is viewed with the fan case 4 and the exhaust duct 41 arranged on the sides of the burner body 3, the depth direction corresponds to the front-rear direction, and the width direction corresponds to the left-right direction. Correspondingly, the height direction corresponds to the vertical direction.

The burner body 3 has a substantially oval shape in a plan view, and is made of stainless metal, for example. Although not shown, the burner body 3 is open downward.

A gas introduction portion communicating with the fan case 4 protrudes upward from the central portion of the burner body 3 . The burner body 3 comprises a planar burner 31 with a downwardly facing combustion surface 30 . Mixed gas is supplied into the burner body 3 by operating the combustion fan.

The burner 31 is of the all-primary air combustion type, and is composed of, for example, a ceramic combustion plate having a large number of downwardly opening flame holes (not shown), or a combustion mat woven with metal fibers in a net shape. The mixed gas supplied into the burner body 3 is jetted downward from the downward-facing combustion surface 30 by the boost pressure of the combustion fan. By igniting this mixed gas, a flame is formed on the combustion surface 30 of the burner 31 and combustion exhaust is generated. Accordingly, combustion exhaust gas ejected from the burner 31 is sent to the heat exchanger 1 through the combustion chamber 2 . The combustion exhaust that has passed through the heat exchanger 1 is then discharged to the outside of the water heater through the drain receiver 40 and the exhaust duct 41 .

That is, in this heat exchanger 1, the upper side where the burner 31 is provided corresponds to the upstream side of the gas flow path of the combustion exhaust, and the lower side opposite to the side where the burner 31 is provided corresponds to the gas flow of the combustion exhaust. Corresponds to the downstream side of the road.

The combustion chamber 2 has a generally oval shape in plan view. The combustion chamber 2 is made of stainless metal, for example. The combustion chamber 2 is formed by bending a single substantially rectangular metal plate and joining both ends thereof so as to open vertically.

As shown in FIG. 2, the heat exchanger 1 has a generally oval shape in plan view. The heat exchanger 1 is a plate-type heat exchanger in which a plurality of (here, ten layers) thin plate-like heat exchange elements 10 are laminated. Note that the heat exchanger 1 may have a housing that covers its periphery.

As shown in FIGS. 2 to 5, the heat exchanger 1 is configured by vertically stacking a plurality (here, three stages) of blocks 5 having a plurality of heat exchange elements 10 (hereinafter, these When collectively referring to the blocks 5, they are simply referred to as "block 5."Also, according to the gas flow path of the combustion exhaust, the uppermost block 5 is the "uppermost block 5a", the middle block 5 is the "middle block 5b", and the lowermost block 5 is referred to as "the most downstream block 5c"). The most upstream block 5a is configured by stacking two heat exchange bodies 10, the midstream block 5b is configured by stacking three heat exchange bodies 10, and the most downstream block 5c is configured by stacking five heat exchange bodies 10. It is constructed by stacking. Note that each block 5 may be composed of one heat exchange body 10 except for the most upstream block 5a. Also, the heat exchanger 1 may be composed of two or less or four or more blocks 5 . As will be described later, when one block 5 is composed of a plurality of heat exchange bodies 10 , water flows in parallel in the same direction inside each of the heat exchange bodies 10 that constitute the one block 5 . Adjacent heat exchange bodies 10 in each block 5 are communicated with each other so that water flows upward from below. Adjacent blocks 5 are communicated with each other so that water flows upward from below. In the adjacent blocks 5, the flow direction of the water flowing inside each heat exchanging body 10 in one block 5 is opposite to the flow direction of the water flowing inside each heat exchanging body 10 in the other block 5. It is configured to be directional. Therefore, in this heat exchanger 1 , the direction of the flow of water in the heat exchanger 1 is turned back for each block 5 so that the flow of water in the heat exchanger 1 has three paths according to the number of stages of the blocks 5 . Thereby, a long water flow path is formed in the heat exchanger 1, and thermal efficiency can be improved.

Next, the configuration of the heat exchange element 10 will be described. Each heat exchange element 10 has a set of upper heat exchange plates 11 and a lower heat exchange plate 11 having a common structure, except for the position of the upper and lower through-holes and the presence or absence of water passage holes in the corners. It is formed by superimposing the plate 12 in the vertical direction and joining predetermined portions, which will be described later, with joining means such as brazing material. Therefore, the configuration of one heat exchange element 10 will be mainly described below. It should be noted that each drawing does not necessarily show actual dimensions and does not limit the embodiments.

As shown in FIGS. 2 to 4, the upper and lower heat exchange plates 11, 12 have a substantially oval shape in plan view. The upper and lower heat exchange plates 11 and 12 are formed of, for example, stainless steel metal plates having a predetermined thickness. Each of the upper and lower heat exchange plates 11 and 12 has a large number of substantially circular upper and lower through holes 11a and 12a on substantially the entire surface of the plate except for the corner portions, and upper and lower through hole flange portions formed on the periphery of the upper and lower through holes 11a and 12a. 11c and 12c. Note that the upper and lower through holes 11a and 12a may have other shapes such as a substantially elliptical shape.

The upper and lower heat exchange plates 11 and 12 are provided with upper and lower peripheral joint portions W1 and W2 that protrude upward. The lower peripheral edge joint portion W2 of the lower heat exchange plate 12 has a gap of a predetermined height between the upper and lower heat exchange plates 11 and 12 when the lower peripheral edge joint portion W2 and the lower surface peripheral edge of the upper heat exchange plate 11 are joined together. It is set to be spaced apart.

Further, the upper peripheral edge joint portion W1 of the upper heat exchange plate 11 is formed when the upper peripheral edge joint portion W1 and the lower surface peripheral edge of the lower heat exchange plate 12 of the heat exchange body 10 adjacent above are joined to each other. The upper heat exchange plate 11 of the body 10 and the lower heat exchange plate 12 of the upper heat exchange body 10 are set to be separated with a gap of a predetermined height.

Therefore, by joining the lower peripheral edge joint W2 of the lower heat exchange plate 12 and the lower surface peripheral edge of the upper heat exchange plate 11, an internal space 14 having a predetermined height is formed (see FIGS. 3 and 4). Also, by joining a plurality of heat exchange bodies 10, an exhaust space 15 having a predetermined height is formed between the vertically adjacent heat exchange bodies 10 (see FIGS. 3 and 4).

The upper and lower through-holes 11a and 12a are formed in a grid pattern at predetermined intervals in the front-rear and left-right directions over substantially the entire surface of the upper and lower heat exchange plates 11 and 12 except for the four corner portions. The upper and lower through-hole flange portions 11c and 12c extend substantially horizontally outward in the circumferential direction from the opening edges of the upper and lower through-holes 11a and 12a, and are formed to have a substantially regular octagonal outer shape in plan view. In this embodiment, the upper and lower through holes 11a and 12a of each heat exchange body 10 have the same size and shape. However, if the pair of upper and lower through-holes 11a and 12a facing each other in the vertical direction are formed to have the same size and shape, the other pair of upper and lower through-holes 11a and 12a are 11a and 12a may be different.

The upper and lower through-holes 11a and 12a and the upper and lower through-hole flange portions 11c and 12c are respectively formed at positions corresponding to each other when the upper and lower heat exchange plates 11 and 12 are overlapped. The upper and lower through-holes 11a and 12a and the upper and lower through-hole flange portions 11c and 12c are in surface contact with the opposing upper and lower through-hole flange portions 11c and 12c when the upper and lower heat exchange plates 11 and 12 are overlapped. , is formed on the bottom surface of the inwardly protruding stepped portion.

Therefore, when the upper and lower heat exchange plates 11 and 12 are superimposed and the upper and lower through-hole flange portions 11c and 12c are joined by a joining means such as brazing material, the inner space 14 is defined by the upper and lower through-hole flange portions 11c and 12c. A closing flange is formed. A through hole 13 is formed through the internal space 14 in a non-communicating state by the upper and lower through holes 11a and 12a.

A plurality of upper and lower concave portions and a plurality of upper and lower convex portions are formed at predetermined intervals on substantially the entire surface of the upper and lower heat exchange plates 11 and 12 excluding the upper and lower through holes 11a and 12a and the upper and lower through hole flange portions 11c and 12c. . These upper and lower concave portions and upper and lower convex portions are respectively formed at positions corresponding to each other when the upper and lower heat exchange plates 11 and 12 are overlapped. Therefore, when the upper and lower heat exchange plates 11 and 12 are overlapped, the upper and lower recesses form an inward stepped portion that reduces the height of the internal space 14 of the heat exchange body 10, and the upper and lower protrusions form an inwardly directed stepped portion that reduces the height of the internal space 14 of the heat exchange body 10. An outward step is formed that increases the height of the space 14 . Note that these uneven portions may not be formed.

As shown in FIG. 5, the through holes 13 of the adjacent heat exchange elements 10 are arranged so that the projected plane of the through holes 13 of the heat exchange element 10 on the upstream side does not overlap the through holes 13 of the heat exchange element 10 on the downstream side. , and is shifted in the left-right direction perpendicular to the direction of the flow path of the combustion exhaust gas. Therefore, the combustion exhaust gas flowing from the upstream side passes through the through holes 13 of one heat exchanging body 10, and then enters the exhaust space 15 between the heat exchanging body 10 and the heat exchanging body 10 adjacent to the downstream side. flow out. The combustion exhaust that has flowed out to the exhaust space 15 collides with the upper heat exchange plate 11 of the heat exchange body 10 adjacent to the downstream side, and flows further downstream from the through hole 13 of the heat exchange body 10 adjacent to the downstream side. . That is, when the combustion exhaust flows through the heat exchanger 1 from the upstream side to the downstream side, a zigzag gas flow path is formed in the heat exchanger 1 . As a result, the contact time between the combustion exhaust and the upper and lower heat exchange plates 11 and 12 in the heat exchanger 1 is increased.

Except for the upper heat exchange plate 11 that forms the most upstream heat exchange element 10 (hereinafter referred to as the "most upstream heat exchange element 10a") of the combustion exhaust gas flow path of the most upstream block 5a, each heat exchange element 10 Each of the upper and lower heat exchange plates 11 and 12 has a water passage hole 63 and a water passage flange portion protruding outward from the periphery of the water passage hole 63 in at least one corner portion. The water passage holes 63 provided in at least one corner portion of the upper and lower heat exchange plates 11 and 12 forming one heat exchange body 10 are arranged in the upper and lower heat exchange plates 11 and 12 when the upper and lower heat exchange plates 11 and 12 are overlapped. , 12 to communicate with an internal space 14 formed between them.

Next, the configuration of block 5 will be described. As shown in FIGS. 3 to 5, each block 5 has an inlet 71 for introducing water into the block 5 and an outlet 72 for discharging water to the outside of the block 5 . These inlets 71 and outlets 72 are formed by predetermined water passage holes 63 of the heat exchange element 10 located at the most downstream and most upstream of the combustion exhaust gas flow path of each block 5, respectively.

The left rear and right front corners of the lower heat exchange plate 12 forming the heat exchange element 10 positioned most downstream in the gas flow path of the combustion exhaust in the most downstream block 5c (hereinafter referred to as "the most downstream heat exchange element 10s"). A water passage hole 63 is formed in the portion. The inflow pipe 20 is connected to the water passage hole 63 in the left rear corner portion. Therefore, this water passage hole 63 forms the introduction port 71 . Further, a lead-out pipe 23 extending upward from the most downstream heat exchanging element 10s to the most upstream heat exchanging element 10a is inserted through the water passage hole 63 in the right front corner portion. The outer peripheral surface of the lead-out pipe 23 is joined to the inner peripheral edge of the water passage hole 63 in the right front corner portion of the lower heat exchange plate 12 forming the most downstream heat exchange body 10s by joining means such as brazing material. The right rear corner portion of the upper heat exchange plate 11 forming the heat exchange element 10 (hereinafter referred to as "first most upstream heat exchange element 10e") positioned most upstream in the combustion exhaust gas flow path of the most downstream block 5c. A water passage hole 63 is formed in the . Therefore, this water passage hole 63 forms the outlet port 72 .

At the right rear corner portion of the lower heat exchange plate 12 forming the heat exchange element 10 (hereinafter referred to as the "first most downstream heat exchange element 10d") positioned most downstream in the gas flow path of the combustion exhaust in the midstream block 5b. is formed with a water passage hole 63 . This water passage hole 63 faces the water passage hole 63 of the first most upstream heat exchange element 10e. Therefore, this water passage hole 63 forms the introduction port 71 . A lead-out pipe 23 is inserted through a water passage hole 63 in a right front corner portion of each heat exchange element 10 constituting the midstream block 5b. Both the left front and rear corner portions of the upper heat exchange plate 11 forming the heat exchange element 10 (hereinafter referred to as the "second most upstream heat exchange element 10c") positioned most upstream in the combustion exhaust gas flow path of the midstream block 5b. A water passage hole 63 is formed in the . Therefore, these water passage holes 63 form outlets 72 . Between the most downstream block 5c and the midstream block 5b, the outlet port 72 of the most downstream block 5c and the inlet port 71 of the midstream block 5b are joined to each other by joining the peripheral water flow hole flange portions of these outlet ports 72. A communication passage 7 is formed to communicate with the introduction port 71 .

The heat exchange element 10 positioned most downstream of the combustion exhaust gas flow path in the most upstream block 5a (that is, the heat exchange element 10 adjacent to the downstream side of the combustion exhaust gas flow path of the most upstream heat exchange element 10a (hereinafter referred to as Water passage holes 63 are formed in both the front and rear corner portions on the left side of the lower heat exchange plate 12 that forms the "second heat exchange body 10b")). These water passage holes 63 face the water passage holes 63 of the second most upstream heat exchange element 10c. Therefore, these water passage holes 63 form the inlet 71 . A lead-out pipe 23 is inserted through a water passage hole 63 in a right front corner portion of each heat exchange element 10 constituting the most upstream block 5a. The upstream end 24 of the lead-out pipe 23 inserted through the most upstream heat exchanging element 10a and the second heat exchanging element 10b communicates with the inner space 14 of the most upstream heat exchanging element 10a and the second heat exchanging element 10b. there is Therefore, the water passage hole 63 in the right front corner portion of the lower heat exchange plate 12 forming the second heat exchange body 10b forms the outlet port 72. As shown in FIG. Between the midstream block 5b and the most upstream block 5a, the outlet port 72 of the midstream block 5b and the inlet port 71 of the most upstream block 5a are joined to each other by joining the peripheral water flow hole flange portions. A communication passage 7 is formed to communicate with the introduction port 71 .

Water passage holes formed in the upper and lower heat exchange plates 11 and 12 except for the water passage holes 63 forming the inlet 71 and the outlet 72 of each block 5 and the water passage holes 63 through which the outlet pipes 23 are inserted. 63 forms a communicating passage 64 by joining the flange portions of the peripheral edges of the water passage holes 63 coaxially located in the vertically adjacent heat exchange bodies 10 . These communicating passages 64 and the already-described communicating passage 7 penetrate the exhaust space 15 in a non-communicating state.

As described above, the lead-out pipe 23 is inserted through the water passage hole 63 in the right front corner portion of all the heat exchanging elements 10 from the most downstream heat exchanging element 10s to the most upstream heat exchanging element 10a. Further, as shown in FIG. 6, a notch portion is formed by notching the peripheral wall at the upstream end portion 24 of the lead-out pipe 23 that is inserted through the most upstream heat exchanging element 10a and the second heat exchanging element 10b. there is Therefore, when the outlet pipe 23 is inserted from the most downstream heat exchange element 10s to the most upstream heat exchange element 10a, the outlet pipe 23 passes through the upstream and downstream openings 25 and 26 formed by the cutouts. It communicates with the internal space 14 of the upstream heat exchange body 10a and the second heat exchange body 10b. Further, the lead-out pipe 23 penetrates through the internal space 14 and all the exhaust spaces 15 of the heat exchange body 10 on the downstream side of the combustion exhaust gas flow path from the second heat exchange body 10b in a non-communicating state.

As shown in FIG. 5, water introduced from the inflow pipe 20 through the inlet 71 into the most downstream block 5c flows upward through the left two rows of communication passages 64, and flows into each heat exchange element 10. diverted. The water flowing into each heat exchange body 10 flows in parallel in each internal space 14 in the same horizontal direction (from left to right in the drawing). Therefore, five parallel water flow paths are formed in the most downstream block 5c. The water flowing through each internal space 14 flows out to the communication passages 64 on the right side, joins them, and flows upward through the communication passages 64 . Then, the water is led out from the outlet port 72 of the most downstream block 5c to the inlet port 71 of the midstream block 5b through the connecting passage 7. As shown in FIG.

The water introduced into the midstream block 5b is branched to each heat exchange element 10 through the communication passages 64 in the right row. The water flowing into each heat exchange body 10 flows in parallel in each internal space 14 in the same horizontal direction (from right to left in the drawing). Therefore, three parallel water flow paths are formed in the midstream block 5b. The flow direction of water flowing through the internal space 14 of each heat exchange element 10 of the midstream block 5b is opposite to that of the most downstream block 5c. The water flowing through each internal space 14 flows out to two rows of communication passages 64 on the left side, merges, and flows upward through the communication passages 64 . Then, the water is led out from the outlet port 72 of the midstream block 5b to the inlet port 71 of the uppermost block 5a through the connecting passage 7 .

The water introduced into the most upstream block 5a passes through the left two rows of communication passages 64 and is divided into the most upstream heat exchanging element 10a and the second heat exchanging element 10b. The water flowing into the uppermost heat exchange element 10a and the second heat exchange element 10b flows in parallel in each internal space 14 in the same lateral direction (from left to right in the drawing). Therefore, two parallel water flow paths are formed in the most upstream block 5a. The flow direction of water flowing through the internal space 14 of each heat exchanging element 10 of the most upstream block 5a is opposite to that of the midstream block 5b. Water flowing through the inner space 14 of the uppermost heat exchange element 10a and the second heat exchange element 10b passes through upstream and downstream openings 25 and 26 formed by notches in the upstream end 24 of the lead-out pipe 23. , and flow out in parallel to the outlet pipe 23 . Since the outlet pipe 23 is inserted through the outlet port 72 of the most upstream block 5a, the water flowing out to the outlet pipe 23 flows down the outlet pipe 23 and is discharged from the outlet pipe 21 connected to the most downstream heat exchanger 10s. It flows out of the heat exchanger 1 .

As shown in FIGS. 5 and 6, the upstream end 24 of the lead-out pipe 23 reaches the uppermost-stream heat exchanger 10a when the lead-out pipe 23 is inserted from the most downstream heat-exchanger 10s to the most upstream heat-exchanger 10a. Two locations in a substantially inverted T shape so that the upstream opening 25 communicating with the internal space 14 of the second heat exchange body 10b has a smaller opening area than the downstream opening 26 communicating with the internal space 14 of the second heat exchange body 10b, Notched (eg, 20% to 50% of downstream opening 26). Therefore, the upstream end 24 of the outlet pipe 23 allows the water flowing out from the most upstream heat exchanging element 10a to the outlet pipe 23 to flow out of the outlet pipe 23 from the second heat exchanging element 10b. is narrower than the outflow side passage 8b.

According to the present embodiment, the combustion exhaust vertically flows through the through-holes 13 penetrating the heat exchange bodies 10 . Therefore, the through holes 13 of each heat exchange body 10 are arranged so that the combustion exhaust flows outside the heat exchange body 10 in a direction substantially perpendicular to the flow path surface of the water flowing inside each heat exchange body 10 . is formed in In addition, the through holes 13 are formed in substantially the entire surface of each heat exchange body 10 at substantially constant intervals in the front-rear and left-right directions. Therefore, the combustion exhaust gas flowing from the upstream side of the gas flow path collides with the entire surface of the most upstream heat exchanging element 10a except for the through holes 13, and heats the most upstream heat exchanging element 10a. That is, in the most upstream heat exchange element 10a, the portion other than the through holes 13 serves as the heat receiving surface. On the other hand, the adjacent heat exchange bodies 10 are formed so that the projected plane of the through holes 13 of the heat exchange body 10 on the upstream side does not overlap the through holes 13 of the heat exchange body 10 on the downstream side. Therefore, the combustion exhaust flowing through the through-holes 13 of the most upstream heat exchange element 10a first collides with the projection surface of the small area on the second heat exchange element 10b. The combustion exhaust that collides with the second heat exchange element 10b exchanges heat with high-temperature combustion exhaust that is not in contact with the most upstream heat exchange element 10a (that is, with water flowing in the internal space 14 of the most upstream heat exchange element 10a). It also includes the combustion exhaust that is not treated). As a result, local overheating tends to occur in the second heat exchange element 10b adjacent to the downstream side of the most upstream heat exchange element 10a.

However, according to the present embodiment, the most upstream heat exchanging element 10a and the second heat exchanging element 10b that constitute the most upstream block 5a are configured such that the water flowing into the most upstream block 5a from the inlet 71 flows into the most upstream heat exchanging element. 10a and the second heat exchanging body 10b, and is configured to flow in parallel through the most upstream heat exchanging body 10a and the second heat exchanging body 10b. Therefore, the flow rate of water flowing through the uppermost heat exchange element 10a and the second heat exchange element 10b has a correlation such that if one increases, the other decreases. In addition, since the upstream end 24 of the lead-out pipe 23 is formed so that the opening area of the upstream opening 25 is smaller than that of the downstream opening 26, the outlet pipe 23 from the most upstream heat exchanger 10a The outflow-side channel 8a of water flowing out to 23 is narrower than the outflow-side channel 8b of water flowing out from the second heat exchange body 10b to the outlet pipe 23. As shown in FIG. Therefore, due to the upstream end 24 of the lead-out pipe 23, the flow path resistance of the water flowing inside the most upstream heat exchanging element 10a becomes higher than that of the water flowing inside the second heat exchanging element 10b. As a result, the upstream end 24 of the lead-out pipe 23 functions as a throttling means for throttling the flow rate of water flowing inside the most upstream heat exchanging element 10a. is greater than that of water flowing inside the most upstream heat exchange element 10a. This prevents local overheating of the second heat exchange body 10b even if the second fluid that has passed through the through holes 13 of the uppermost heat exchange body 10a concentrates on the small projection surface of the second heat exchange body 10b. be able to. Note that the upstream end 24 of the lead-out pipe 23 may be provided with a hole penetrating the peripheral wall in addition to the notch.

Further, according to the present embodiment, since the outflow-side channel 8a of the water flowing out from the most upstream heat exchange element 10a to the outlet pipe 23 is narrowed by the upstream end portion 24 of the outlet pipe 23, the most upstream heat is The flow path resistance of water can be increased on the most downstream side of the flow path of water flowing through the inside of the exchange body 10a. As a result, even when the flow rate of water supplied into the heat exchanger 1 is small, water can be smoothly circulated inside the most upstream heat exchanging element 10a, and local overheating in the most upstream heat exchanging element 10a can be prevented. can do. In addition, it is possible to suppress the fluctuation of the flow path resistance of water when the water flows through the intermediate portion of the internal space 14 of the uppermost heat exchange element 10a. As a result, it is possible to reduce unevenness in the temperature of the most upstream heat exchange element 10a heated by the combustion exhaust gas, and to improve the thermal efficiency.

Further, according to the present embodiment, since the outlet pipe 23 can increase the flow path resistance of the water flowing through the inside of the most upstream heat exchanging body 10a, As 10b, there is no need to manufacture a dedicated heat exchange body 10. Therefore, the heat exchanging element 10 having substantially the same configuration as the other heat exchanging elements 10 can be used for the most upstream heat exchanging element 10a and the second heat exchanging element 10b. Thereby, cost can be reduced.

Further, according to the present embodiment, the upstream end 24 of the lead-out pipe 23 has upstream and downstream openings 25 communicating with the internal spaces 14 of the most upstream heat exchanging element 10a and the second heat exchanging element 10b. , 26 are formed in plurality. Therefore, it is difficult for water to stagnate around the upstream end 24 of the outlet pipe 23 , and the water can smoothly flow out from the internal space 14 to the outlet pipe 23 . Thereby, even when the flow rate of water supplied into the heat exchanger 1 is small, it is possible to prevent local heat in the uppermost heat exchange element 10a and the second heat exchange element 10b.

As described above, according to the present embodiment, high-temperature combustion exhaust gas collides with the second heat exchange element 10b through the through holes 13 of the most upstream heat exchange element 10a, causing the second heat exchange element 10b to Local heat can be prevented. Therefore, local boiling of the water flowing inside the second heat exchange body 10b can be prevented, and damage to the second heat exchange body 10b due to an increase in the internal pressure of the second heat exchange body 10b can be prevented. The durability of the container 1 can be improved.

(Other embodiments)
(1) In the above embodiment, the most upstream block is configured by stacking two heat exchange bodies. However, the most upstream heat exchange body may be configured by stacking three or more heat exchange bodies. In this case, preferably, the three or more heat exchange bodies are configured such that the flow rate of the first fluid flowing inside the second heat exchange body is maximized. As a result, the first fluid can be circulated at the maximum flow rate inside the second heat exchange body among the plurality of heat exchange bodies constituting the most upstream block, so that local heating of the second heat exchange body can be ensured. can be prevented.
(2) In the above embodiment, the throttle means is formed by the upstream end of the lead-out pipe. However, without using the outlet pipe, the opening area of the water passage hole on the downstream side of the first fluid in the most upstream heat exchange element is made smaller than that of the water passage hole on the downstream side of the first fluid in the second heat exchange element. may In this case, the water passage hole itself of the most upstream heat exchanger forms the throttle means.
(3) In the above-described embodiment, the upstream end of the outlet pipe inserted through the most upstream heat exchange element constricts the outflow-side passage through which the first fluid flows from the most upstream heat exchange element to the outlet tube. . However, the position where the throttle means is formed is not particularly limited. For example, a throttling means may be formed in the inflow-side channel of the first fluid in the most upstream heat exchange element. Moreover, throttle means may be formed in both the inflow side channel and the outflow side channel in the most upstream heat exchange element.
(4) In the above embodiment, a burner with a downward combustion surface is arranged above the heat exchanger. However, a burner with an upwardly facing combustion surface may also be arranged below the heat exchanger.
(5) In the above embodiments, a plurality of heat exchange bodies are stacked vertically. However, a plurality of heat exchange bodies may be stacked on the left and right.
(6) In the above embodiment, a water heater is used, but a heat source machine such as a boiler may be used.

REFERENCE SIGNS LIST 1 heat exchanger 10 heat exchanger 10a most upstream heat exchanger 10b second heat exchanger 5 block 5a most upstream block 13 through hole 23 outlet pipe

Claims (4)

A plate heat exchanger comprising a plurality of blocks each having a heat exchange body for exchanging heat between a first fluid circulating inside and a second fluid circulating outside, wherein the plurality of blocks are stacked. and
The heat exchange body has a plurality of through holes formed so that the second fluid flows outside the heat exchange body in a direction intersecting with a flow path surface of the first fluid flowing inside the heat exchange body. has
Adjacent heat exchange bodies are formed so that the projected surface of the through hole of one heat exchange body does not overlap the through hole of the other heat exchange body when viewed from the flow path direction of the second fluid,
each block has an inlet for introducing the first fluid into each block and an outlet for introducing the first fluid to the outside of each block;
In the adjacent blocks, the flow direction of the first fluid flowing through the heat exchanging bodies constituting one block is the first fluid flowing through the heat exchanging bodies constituting the other block. formed differently from that of a fluid,
A communication passage is formed between the adjacent blocks to communicate the outlet port of the one block and the inlet port of the other block,
Among the plurality of blocks, the most upstream block positioned most upstream in the flow path of the second fluid is configured by stacking at least two or more heat exchange bodies,
The two or more heat exchange bodies constituting the most upstream block are formed so that the first fluid flows in parallel inside the two or more heat exchange bodies,
Among the two or more heat exchange bodies constituting the most upstream block, the most upstream heat exchange body positioned most upstream in the flow path of the second fluid, and the second most upstream heat exchange body The second heat exchange body adjacent to the downstream side of the flow path of the fluid is the flow rate of the first fluid flowing inside the second heat exchange body, the flow rate of the first fluid flowing inside the most upstream heat exchange body A plate heat exchanger configured to be greater than that of the first fluid. In the plate heat exchanger of claim 1,
The most upstream block is configured by stacking three or more heat exchange bodies,
A plate heat exchanger, wherein the three or more heat exchange elements constituting the most upstream block are configured to maximize the flow rate of the first fluid flowing through the second heat exchange elements. . In the plate heat exchanger according to claim 1 or 2,
throttling means for throttling the flow rate of the first fluid flowing through the most upstream heat exchange body to at least one of an inflow side flow path and an outflow side flow path of the first fluid in the most upstream heat exchange body; A plate heat exchanger in which is formed. In the plate heat exchanger according to claim 3,
a lead-out pipe is inserted from the most downstream heat exchange element located most downstream in the flow path of the second fluid to the most upstream heat exchange element,
The outlet pipe is configured such that the first fluid flows out from the most upstream heat exchanger and the second heat exchanger into the outlet pipe,
The outflow pipe allows the first fluid to flow out from the most upstream heat exchanging element to the outflow pipe so that the first fluid flows out from the second heat exchanging element to the outflow pipe. A plate heat exchanger that is formed to be narrower.

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