JP7373332B2 - plate heat exchanger - Google Patents

Description

The present invention has a plurality of heat exchange bodies that perform heat exchange between a first fluid flowing inside and a second fluid flowing outside, and a plate type configured by stacking a plurality of heat exchange bodies. Regarding heat exchangers.

Conventionally, a plate heat exchanger including a plurality of heat exchange bodies in which an upper heat exchange plate and a lower heat exchange plate are joined has been proposed (for example, Patent Document 1). Each heat exchange body has an internal space in which a heat medium, which is a first fluid, flows between an upper heat exchange plate and a lower heat exchange plate, and a combustion exhaust gas, which is a second fluid, that passes through the internal space in a non-communicating state. has a plurality of through holes that communicate in the vertical direction.

Korean Registered Patent No. 10-1608149

By the way, in a plate heat exchanger in which multiple heat exchangers are stacked, the projected plane of the through holes of one heat exchanger overlaps with the throughholes of the other heat exchanger when viewed from the direction of the combustion exhaust flow path. If the adjacent heat exchange bodies are formed so that the heat exchanger does not become hot, the gas flow path of the combustion exhaust gas in the heat exchanger becomes long, and the thermal efficiency can be improved. Furthermore, by forming through holes with as small an opening area as possible, the heat receiving area of the heat exchanger becomes large, and thermal efficiency can be improved.

However, in a heat exchanger having the through-hole arrangement structure as described above, the through-holes of the upstream heat exchanger face the projected surface of the downstream heat exchanger where no through-holes are formed. Therefore, the combustion exhaust gas that has passed through the through holes of the upstream heat exchanger first collides with the projected surface on one side of the downstream heat exchanger, and then spreads onto the one side of the downstream heat exchanger. , further flows downstream from the through holes of the heat exchanger on the downstream side. Therefore, in the upstream region of the combustion exhaust gas flow path through which high-temperature combustion exhaust flows, the portion of the downstream heat exchanger that faces the through hole of the upstream heat exchanger is heated intensively, and local heat is generated. There is a problem that arises. In particular, in the downstream heat exchanger adjacent to the most upstream heat exchanger in the combustion exhaust gas flow path, the most upstream heat exchanger does not exchange heat with the heat medium flowing inside the most upstream heat exchanger. Since high-temperature combustion exhaust flowing through the through-holes of the heat exchanger collides with each other, local heat problems tend to occur.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a plate heat exchanger that can prevent local heating of a heat exchanger in an upstream region of a second fluid flow path. Our goal is to provide the following.

According to the invention,
A plate heat exchanger comprising a plurality of heat exchange bodies that perform heat exchange between a first fluid flowing inside and a second fluid flowing outside, and configured by stacking the plurality of heat exchange bodies. There it is,
The heat exchange body includes a plurality of through holes formed so that the second fluid flows outside the heat exchange body in a direction intersecting a flow path surface of the first fluid flowing inside the heat exchange body. has
Adjacent heat exchange bodies are formed such that a projected surface of the through hole of one heat exchange body does not overlap with the through hole of the other heat exchange body when viewed from the flow path direction of the second fluid,
Each heat exchanger in the upstream heat exchange group, including at least the most upstream heat exchanger located at the most upstream side of the flow path for the second fluid, is arranged downstream of the flow path for the second fluid in the upstream heat exchange group. The plate type is formed so that the total opening area of the plurality of through holes is larger than that in the downstream heat exchange group from the heat exchanger adjacent to the side to the most downstream heat exchanger located at the most downstream side. A heat exchanger is provided.

According to the above heat exchanger, the total area of the projected surface of the through hole of each heat exchanger in the upstream heat exchanger group to the downstream adjacent heat exchanger is the larger than that of the through hole. Therefore, the total heat receiving area of the portion where the second fluid flows through the through holes of each heat exchanger in the upstream heat exchanger group and collides with the downstream adjacent heat exchanger is the It is larger than that of the portion that flows through the through hole of each heat exchanger in the exchange group and collides with the adjacent heat exchanger on the downstream side. Therefore, when the second fluid flowing through the through holes of each heat exchanger in the upstream heat exchange group collides with the downstream adjacent heat exchanger, the heat transferred from the second fluid to the heat exchanger is concentrated. It can be relaxed. This prevents local overheating of the downstream adjacent heat exchange body when the second fluid flowing through the through holes of each heat exchange body in the upstream heat exchange group collides with the downstream adjacent heat exchange body. can do.

Preferably, in the heat exchanger,
The upstream heat exchange group includes from the most upstream heat exchange body to a heat exchange body at a predetermined position on the downstream side of the flow path of the second fluid.

According to the heat exchanger, not only the most upstream heat exchange body but also the heat exchange bodies from the most upstream heat exchange body to a predetermined position on the downstream side have a large total opening area of the through holes. Therefore, the internal space of the heat exchanger on the downstream side is reduced, and the distance between adjacent through holes is shortened. As a result, when the first fluid flows inside the heat exchanger on the downstream side, the flow velocity of the first fluid increases, and more of the first fluid flows around the projected surface of the through hole of the heat exchanger on the upstream side. flows. Therefore, heat around the projection surface of the through hole can be released. Thereby, local overheating of the heat exchanger on the downstream side can be prevented.

Preferably, in the heat exchanger,
Each of the heat exchange bodies in the upstream heat exchange group is formed such that the maximum opening area of the through hole is larger than that in the downstream heat exchange group.

Each heat exchange element in the upstream heat exchange group is contacted with a second fluid having a higher temperature than each heat exchange element in the downstream heat exchange group. Furthermore, the higher the temperature of the second fluid, the greater the pressure loss when the second fluid passes through the through hole. Therefore, when the through holes of each heat exchange body in the upstream heat exchange group are smaller than those of each heat exchange body in the downstream heat exchange group, the second fluid penetrates through each heat exchange body in the upstream heat exchange group. The pressure loss when passing through the hole increases. However, by making the opening area of the largest through hole of each heat exchanger in the upstream heat exchange group larger than that of the largest through hole of each heat exchanger in the downstream heat exchange group, each heat exchanger in the upstream heat exchange group The pressure loss of the second fluid passing through the through holes of the heat exchanger can be reduced.

Preferably, in the heat exchanger,
Each of the heat exchangers in the upstream heat exchange group is formed such that the volume of the first fluid flow path is larger than that in the downstream heat exchange group.

When the total opening area of the through holes of the heat exchanger is increased, the flow path of the first fluid flowing inside the heat exchanger becomes narrower, and the flow path resistance of the first fluid increases. However, according to the heat exchanger, the flow path of the first fluid flowing inside each heat exchanger in the upstream heat exchange group is larger than that of the first fluid flowing inside each heat exchanger in the downstream heat exchange group. Since it has a volume, an increase in flow path resistance of the first fluid can be suppressed.

As described above, according to the present invention, when viewed from the flow path direction of the second fluid, the projected plane of the through-holes of one of the adjacent heat exchangers overlaps with the through-hole of the other heat exchanger. In a plate heat exchanger in which a plurality of heat exchange bodies are stacked so that the heat exchange bodies are not heated, local heating of the heat exchange bodies in the upstream region of the second fluid flow path can be prevented. This makes it possible to prevent boiling and denaturation of the first fluid, as well as to prevent deformation of the heat exchanger, making it possible to provide a heat exchanger with excellent durability.

FIG. 1 is a schematic partially cutaway perspective view showing a heat source device having a heat exchanger according to Embodiment 1 of the present invention. FIG. 2 is a schematic partially exploded perspective view showing the heat exchanger according to Embodiment 1 of the present invention. FIG. 3 is a schematic enlarged sectional view of the main parts of the inlet pipe side showing the heat exchanger according to Embodiment 1 of the present invention. FIG. 4 is a schematic enlarged sectional view of essential parts on the outflow pipe side showing the heat exchanger according to Embodiment 1 of the present invention. FIG. 5 is a schematic diagram illustrating the flow of the first fluid and the second fluid in the heat exchanger according to Embodiment 1 of the present invention. FIG. 6 is a schematic diagram illustrating the flow of the first fluid and the second fluid in the heat exchanger according to Embodiment 2 of the present invention. FIG. 7 is a schematic diagram illustrating the flow of the first fluid and the second fluid in the heat exchanger according to Embodiment 3 of the present invention.

(Embodiment 1)
Hereinafter, a plate heat exchanger and a heat source device including the same according to the present embodiment will be specifically described with reference to the accompanying drawings.

As shown in FIG. 1, the heat source device according to the present embodiment converts water (first fluid) flowing into the heat exchanger 1 from the inflow pipe 20 into combustion exhaust (second fluid) generated by the burner 31. This is a water heater that heats the hot water and supplies it to hot water users (not shown) such as showers and showers through an outflow pipe 21. Although not shown, the water heater is incorporated within 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 the top. Moreover, a fan case 4 including a combustion fan that feeds a mixed gas of fuel gas and air into the burner body 3 is disposed on one side of the burner body 3 (on the right side in FIG. 1). Further, on the other side of the burner body 3 (on the left side in FIG. 1), an exhaust duct 41 communicating with the drain receiver 40 is provided. The exhaust duct 41 discharges combustion exhaust gas discharged into 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. The height direction corresponds to the vertical direction.

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

A gas introduction part communicating with the fan case 4 projects upward from the center of the burner body 3. The burner body 3 includes a planar burner 31 having a downward combustion surface 30. A mixed gas is supplied into the burner body 3 by operating the combustion fan.

The burner 31 is an all-primary air combustion type, and is made of, for example, a ceramic combustion plate having a large number of flame holes (not shown) that open downward, or a combustion mat made of metal fibers woven into a net. The mixed gas supplied into the burner body 3 is ejected downward from the downward facing combustion surface 30 by the supply 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 gas is generated. Therefore, the combustion exhaust emitted from the burner 31 is sent to the heat exchanger 1 via the combustion chamber 2. Next, the combustion exhaust gas that has passed through the heat exchanger 1 is 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 gas, and the lower side opposite to the side where the burner 31 is provided corresponds to the gas flow path of the combustion exhaust gas. 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, for example, stainless metal. The combustion chamber 2 is formed by curving a substantially rectangular metal plate and joining both ends so as to be 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 heat exchanger in which a plurality of thin plate heat exchange bodies 10 are stacked. Note that the heat exchanger 1 may have a housing that covers the periphery thereof.

3 and 4 are schematic enlarged sectional views showing four heat exchange bodies 10 in the upstream region of the combustion exhaust gas flow path of the heat exchanger 1. The heat exchanger 1 is configured by vertically stacking a plurality of blocks 5 each having one or more heat exchangers 10. The most upstream block 5 (hereinafter referred to as the "most upstream block 5a") and the downstream block 5 adjacent to the most upstream block 5a (hereinafter referred to as the "first downstream block 5b") each have one heat exchanger. It consists of 10. Moreover, a block adjacent to the downstream side of the first downstream block 5b (hereinafter referred to as "second downstream block 5c") is configured by stacking a plurality of heat exchange bodies 10. As will be described later, when one block 5 is composed of a plurality of heat exchangers 10, water flows in parallel in the same direction inside each heat exchanger 10 that constitutes one block 5. Adjacent heat exchangers 10 in each block 5 are interconnected so that water flows from below to above. Further, adjacent blocks 5 are interconnected so that water flows from below to above. Further, in the adjacent blocks 5, the flow path direction of water flowing inside each heat exchanger 10 in one block 5 is opposite to the flow path direction of water flowing inside each heat exchanger 10 in the other block 5. It is configured to be oriented. Although not shown, in this heat exchanger 1, the direction of the water flow path is turned back for each block 5 so that the water flow path within the heat exchanger 1 has four passes depending on the number of stages of the blocks 5. . Thereby, a long water flow path is formed within the heat exchanger 1, and thermal efficiency can be improved.

Next, the configuration of the heat exchanger 10 will be explained. Each heat exchange body 10 exchanges heat with a pair of upper heat exchange plates 11 having the same configuration, except for some configurations such as the positions of upper and lower through holes and the presence or absence of water holes at corners. It is formed by overlapping the plates 12 in the vertical direction and joining them at predetermined locations, which will be described later, using joining means such as brazing material. Furthermore, local heat occurs in the heat exchanger 10 in the upstream region of the combustion exhaust gas flow path through which high-temperature combustion exhaust flows. Therefore, in the following, the heat exchanger 10 located at the most upstream side of the combustion exhaust gas flow path (hereinafter referred to as the "most upstream heat exchanger 10a") and the two heat exchangers downstream from the most upstream heat exchanger 10a will be described. The structure of the body 10 (hereinafter referred to as "second heat exchange body 10b" and "third heat exchange body 10c" in order from the upstream side) will mainly be described. Note 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 and 12 have a substantially oval shape in plan view. The upper and lower heat exchange plates 11 and 12 are formed, for example, from stainless steel metal plates having a predetermined thickness. The upper and lower heat exchange plates 11 and 12 each have a large number of substantially circular upper and lower through holes 11a and 12a on substantially the entire surface of the plate excluding the corner portions, and upper and lower through hole flange portions formed at the peripheries 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.

Upper and lower peripheral edge joining portions W1 and W2 that protrude upward are formed on the peripheral edges of the upper and lower heat exchange plates 11 and 12, respectively. The lower peripheral edge joint W2 of the lower heat exchange plate 12 is such that when the lower peripheral edge joint W2 and the lower surface peripheral edge of the upper heat exchange plate 11 are joined, the upper and lower heat exchange plates 11 and 12 have a gap of a predetermined height. It is set to be spaced apart.

Further, the upper peripheral edge joint W1 of the upper heat exchange plate 11 is formed when the upper peripheral edge joint W1 and the lower surface peripheral edge of the lower heat exchange plate 12 of the heat exchanger 10 adjacent to the upper side are joined together. 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 apart from each other 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 average height is formed (see FIGS. 3 and 4). . Further, by joining a plurality of heat exchange bodies 10, an exhaust space 15 having a predetermined average height is formed between 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 longitudinal and lateral directions over substantially the entire surface of the upper and lower heat exchange plates 11 and 12, excluding the four corners. Further, the upper and lower through-hole flange portions 11c and 12c are formed so as to extend substantially horizontally outward in the circumferential direction from the opening edges of the upper and lower through-holes 11a and 12a, and 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 exchanger 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 upper and lower through holes 11a and 12a of each heat exchanger 10 will be different from the other pair of upper and lower through holes. It may be different from those of 11a and 12a.

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 stacked. Further, the upper and lower through-holes 11a and 12a and the upper and lower through-hole flange parts 11c and 12c are drawn so that when the upper and lower heat exchange plates 11 and 12 are overlapped, the opposing upper and lower through-hole flange parts 11c and 12c come into surface contact. It is formed on the bottom surface of the stepped portion that protrudes inward.

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

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 stacked on top of each other. Therefore, when the upper and lower heat exchange plates 11 and 12 are overlapped, the upper and lower concave portions form an inward stepped portion that reduces the height of the internal space 14 of the heat exchanger 10, and the upper and lower convex portions form an inward step that reduces the height of the internal space 14 of the heat exchanger 10. An outward step is formed that increases the height of the space 14. Note that these uneven portions may not be formed.

Except for the upper heat exchange plate 11 forming the most upstream heat exchange element 10a, each of the upper and lower heat exchange plates 11 and 12 of each heat exchange element 10 has a water passage hole 63 and a water passage hole in at least one corner. 63, and a water passage flange portion protruding outward from the periphery of the water passage hole 63. The water passage holes 63 provided in at least one corner of the upper and lower heat exchange plates 11 and 12 that form one heat exchanger 10 are arranged so that when the upper and lower heat exchange plates 11 and 12 are overlapped, the upper and lower heat exchange plates 11 , 12, and is open to communicate with an internal space 14 formed between them.

FIG. 5 is a schematic diagram illustrating the flow of combustion exhaust gas and water in the heat exchanger 1. Note that, in order to avoid complication, the uneven portions and the flange portions around the through holes are omitted in FIG.

Opposing water passage holes 63 are formed in the front right corners of the upper heat exchange plate 11 forming the third heat exchange body 10c and the lower heat exchange plate 12 forming the second heat exchange body 10b. Further, opposing water passage holes 63 are formed in both the left front and rear corners of the upper heat exchange plate 11 forming the second heat exchange body 10b and the lower heat exchange plate 12 forming the most upstream heat exchange body 10a. ing. The water passage holes 63 formed in these upper and lower heat exchange plates 11 and 12 connect the water passage hole flange portions of the peripheral edges of the water passage holes 63 located on the same axis of the vertically adjacent heat exchange bodies 10 to each other. This forms a communication path that allows the vertically adjacent heat exchange bodies 10 to communicate with each other.

In the water passage hole 63 at the front left corner of the lower heat exchange plate 12 that forms the heat exchange body located at the most downstream position of the combustion exhaust gas flow path (hereinafter referred to as the "most downstream heat exchange body 10s"), An inflow pipe 20 is connected. In addition, a water passage hole 63 at the rear right corner of the lower heat exchange plate 12 forming the most downstream heat exchange body 10s has a lead-out hole extending upward from the most downstream heat exchange body 10s to the most upstream heat exchange body 10a. A tube 23 is inserted therethrough. The upper end of the outlet pipe 23 is connected to a water passage hole 63 at the rear right corner of the lower heat exchange plate 12 forming the most upstream heat exchange body 10a. The outer peripheral surface of the outlet pipe 23 is joined to the inner peripheral edge of the water passage hole 63 at the rear right corner of the lower heat exchange plate 12 forming the most downstream heat exchange body 10s by joining means such as brazing material. Further, the upper end opening of the outlet pipe 23 communicates with the internal space 14 of the most upstream heat exchanger 10a. Furthermore, when the outlet pipe 23 is inserted from the most downstream heat exchanger 10s to the most upstream heat exchanger 10a, the outlet pipe 23 is inserted into the internal space 14 of the heat exchanger 10 other than the most upstream heat exchanger 10a and all the exhaust spaces. 15 in a non-communicating state.

Therefore, in the upstream region of the combustion exhaust gas flow path, the water flowing into the internal space 14 of the third heat exchanger 10c from the water passage holes 63 at both the front and rear corners on the left side flows through the internal space 14 in the left-right direction. direction (from left to right in FIG. 5). Further, water flowing into the internal space 14 of the second heat exchanger 10b from the water passage hole 63 in the right front corner section flows in one direction in the left-right direction (from the right side to the left side in FIG. 5) within the internal space 14. flows. The flow path direction of water flowing through the internal space 14 of the second heat exchange body 10b is opposite to that of the third heat exchange body 10c. In addition, water flowing into the internal space 14 of the most upstream heat exchanger 10a from the water passage holes 63 in both the front and rear corners on the left side flows in one direction in the left and right direction (from the left to the right in FIG. 5) within the internal space 14. flows to The flow path direction of water flowing through the internal space 14 of this most upstream heat exchanger 10a is opposite to that of the second heat exchanger 10b. The water flowing in the internal space 14 of the most upstream heat exchanger 10a flows out into the outlet pipe 23 inserted into the water passage hole 63 at the right rear corner of the most upstream heat exchanger 10a. The water flowing into the outlet pipe 23 flows down the outlet pipe 23 and flows out of the heat exchanger 1 from the outlet pipe 21 connected to the most downstream heat exchanger 10s.

As shown in FIGS. 3 to 5, the through holes 13 of adjacent heat exchange bodies 10 have a projection plane that overlaps the through holes 13 of the downstream heat exchange body 10. It is shifted in the left-right direction that intersects perpendicularly to the direction of the combustion exhaust flow path to prevent Therefore, the combustion exhaust gas flowing from the upstream side passes through the through hole 13 of one heat exchanger 10 and then enters the exhaust space 15 between that heat exchanger 10 and the adjacent heat exchanger 10 on the downstream side. It flows out. Then, the combustion exhaust gas flowing into 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 gas flows from the upstream side to the downstream side within the heat exchanger 1, a zigzag gas flow path is formed within the heat exchanger 1. This increases the contact time between the combustion exhaust gas in the heat exchanger 1 and the upper and lower heat exchange plates 11 and 12.

Further, each through hole 13 of the second heat exchange body 10b and the third heat exchange body 10c is formed to have approximately the same opening area, but each through hole 13 of the most upstream heat exchange body 10a is It is formed to have a larger opening area than that of the second heat exchanger 10b and the third heat exchanger 10c (for example, 150 to 200% of the opening area of each through hole 13 of the second heat exchanger 10b). ). The number of through holes 13 in each heat exchange body 10 is set to be the same so that the projected plane of the through holes 13 in the upstream heat exchange body 10 does not overlap with the through holes 13 in the downstream heat exchange body 10. The distances between the centers of adjacent through holes 13 in the heat exchanger 10 are set to be substantially the same. Therefore, the distance between adjacent through holes 13 in the most upstream heat exchange body 10a is smaller than that between adjacent through holes 13 in the second heat exchange body 10b and the third heat exchange body 10c. That is, the most upstream heat exchanger 10a has a larger total opening area of the through holes 13 than the second heat exchanger 10b and the third heat exchanger 10c (for example, the total opening area of the through holes 13 of the second heat exchanger 10b 150-200% of the opening area). Although not shown, each through hole 13 of the heat exchanger 10 from the third heat exchanger 10c to the most downstream heat exchanger 10s has substantially the same shape and size as that of the third heat exchanger 10c. Therefore, in this embodiment, the most upstream heat exchange body 10a constitutes the upstream heat exchange group 9a, and the heat exchange bodies 10 from the second heat exchange body 10b to the most downstream heat exchange body 10s constitute the downstream heat exchange group. 9b.

According to this embodiment, combustion exhaust gas flows vertically through the through holes 13 that penetrate each heat exchanger 10 . Therefore, the through holes 13 of each heat exchanger 10 are arranged so that the combustion exhaust gas flows through the outside of the heat exchanger 10 in a direction substantially perpendicular to the flow path surface of the water flowing inside each heat exchanger 10. is formed. Further, the through holes 13 are formed on substantially the entire surface of each heat exchanger 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 exchange body 10a except for the through holes 13, and heats the most upstream heat exchange body 10a. That is, in the most upstream heat exchanger 10a, the portion excluding the through holes 13 becomes a 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 upstream heat exchange body 10 does not overlap with the through holes 13 of the downstream heat exchange body 10. Therefore, the combustion exhaust gas flowing through the through holes 13 of the most upstream heat exchanger 10a first collides with the small-area projection surface on the second heat exchanger 10b. The combustion exhaust gas that collides with the second heat exchanger 10b exchanges heat with the high-temperature combustion exhaust gas that is not in contact with the most upstream heat exchanger 10a (that is, the water flowing through the internal space 14 of the most upstream heat exchanger 10a). It also includes combustion exhaust (for which combustion exhaust gas is not used). As a result, local overheating tends to occur in the second heat exchanger 10b adjacent to the downstream side of the most upstream heat exchanger 10a.

However, according to the present embodiment, the through holes 13 of the most upstream heat exchanger 10a are formed to have a larger total opening area than that of the second heat exchanger 10b, so the most upstream heat exchanger The total area of the projection surface where the through holes 13 of the exchanger 10a are projected onto the second heat exchanger 10b is larger than that of the projection surface where the through holes 13 of the second heat exchanger 10b are projected onto the third heat exchanger 10c. big. Therefore, the total heat receiving area of the portion where the combustion exhaust flows through the through-holes 13 of the most upstream heat exchanger 10a and collides with the second heat exchanger 10b is as follows: It is larger than that of the portion that flows and collides with the third heat exchanger 10c. Thereby, the concentration of heat transferred from the combustion exhaust to the second heat exchange body 10b is alleviated, and local overheating of the second heat exchange body 10b can be prevented.

Further, according to the present embodiment, only the most upstream heat exchanger 10a constituting the upstream heat exchange group 9a has the large through hole 13, and the most downstream heat exchanger 10s constituting the downstream heat exchange group 9b. Since the heat exchanger 10 from the to the second heat exchanger 10b has small through holes 13, even if the flow rate of water flowing inside the most upstream heat exchanger 10a decreases, the thermal efficiency of the entire heat exchanger 1 will be reduced. The decline can be suppressed.

Preferably, each heat exchange body 10 in the upstream heat exchange group 9a is formed so that the opening area of the maximum through hole 13 is larger than that in the downstream heat exchange group 9b. Each heat exchange body 10 in the upstream heat exchange group 9a is contacted with combustion exhaust gas having a higher temperature than each heat exchange body 10 in the downstream heat exchange group 9b. Furthermore, the higher the temperature of the combustion exhaust, the greater the pressure loss when the combustion exhaust passes through the through hole 13. Therefore, when the through holes 13 of each heat exchange body 10 in the upstream heat exchange group 9a are smaller than those of each heat exchange body 10 in the downstream heat exchange group 9b, the combustion exhaust gas is The pressure loss when passing through the through holes 13 of the heat exchanger 10 increases. However, by making the opening area of the maximum through hole 13 of each heat exchange body 10 in the upstream heat exchange group 9a larger than that of the maximum through hole 13 of each heat exchange body 10 in the downstream heat exchange group 9b, the upstream The pressure loss of the combustion exhaust gas passing through the through holes 13 of each heat exchange body 10 in the side heat exchange group 9a can be reduced.

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

(Embodiment 2)
The heat exchanger 1a according to the present embodiment has the same configuration as the heat exchanger 1 according to the first embodiment, except that the configuration of the block 5 is different. Therefore, only the different configurations from Embodiment 1 will be explained, and the explanation of the same configurations will be omitted.

As shown in FIG. 6, in the heat exchanger 1a of the present embodiment, water flows through the internal spaces 14 of the most upstream heat exchanger 10a and the second heat exchanger 10b in the same direction in the left-right direction (from the left side in FIG. (right side) so that they flow in parallel. Therefore, two parallel flow paths are formed in the most upstream block 5a. Therefore, in this embodiment, the most upstream heat exchange body 10a and the second heat exchange body 10b constitute the most upstream block 5a, and the third heat exchange body 10c constitutes the first downstream block 5b.

Furthermore, although the most upstream heat exchange body 10a and the second heat exchange body 10b belong to the same most upstream block 5a, only the most upstream heat exchange body 10a has large through holes 13, as in the first embodiment. Therefore, the most upstream heat exchange body 10a constitutes the upstream heat exchange group 9a, and the heat exchange bodies 10 from the second heat exchange body 10b to the most downstream heat exchange body 10s constitute the downstream heat exchange group 9b.

Therefore, according to the present embodiment, as in the first embodiment, the total opening area of the through holes 13 of the most upstream heat exchanger 10a and the opening area of each through hole 13 are equal to those of the second heat exchanger 10b. , it is possible to prevent local overheating of the second heat exchanger 10b. Furthermore, according to the present embodiment, the water flow path is formed such that water flows in parallel in the same direction within the internal spaces 14 of the plurality of heat exchangers 10 in the upstream region of the combustion exhaust gas flow path. . Therefore, the flow path resistance of water flowing inside the internal space 14 of these heat exchangers 10 can be reduced. Thereby, even if the flow rate of water supplied to the heat exchanger 1 decreases, local heat can be prevented.

(Embodiment 3)
Heat exchanger 1b according to this embodiment has the same configuration as heat exchanger 1 according to Embodiment 1, except that the configuration of block 5 and the configuration of second heat exchanger 10b are different. Therefore, only the different configurations from Embodiment 1 will be explained, and the explanation of the same configurations will be omitted.

As shown in FIG. 7, in the heat exchanger 1b of the present embodiment, as in the second embodiment, water occupies the inner space 14 of the most upstream heat exchanger 10a and the second heat exchanger 10b in the same direction in the left and right direction. They are formed to flow in parallel in the direction (from left to right in FIG. 5). Therefore, two parallel flow paths are formed in the most upstream block 5a. Therefore, in this embodiment, the most upstream heat exchange body 10a and the second heat exchange body 10b constitute the most upstream block 5a, and the third heat exchange body 10c constitutes the first downstream block 5b.

Moreover, each through hole 13 of the second heat exchange body 10b has substantially the same shape and size as that of the most upstream heat exchange body 10a. Moreover, each through hole 13 of the heat exchange body 10 from the third heat exchange body 10c to the most downstream heat exchange body 10s has substantially the same shape and size as that of the third heat exchange body 10c. Therefore, in this embodiment, the most upstream heat exchanger 10a and the second heat exchanger 10b constitute an upstream heat exchange group 9a, and the heat exchangers from the third heat exchanger 10c to the most downstream heat exchanger 10s 10 constitutes the downstream heat exchange group 9b.

According to this embodiment, the second heat exchange body 10b has a large total opening area of the through holes 13, similarly to the most upstream heat exchange body 10a. Therefore, the internal space 14 of the second heat exchanger 10b is reduced, and the distance between adjacent through holes 13 is shortened. As a result, when water flows inside the second heat exchange body 10b, the flow rate of the water increases and more water flows around the projected surface of the through hole 13 of the first heat exchange body 10a. Therefore, heat around the projection surface of the through hole 13 can be efficiently released to water. Thereby, local overheating of the second heat exchanger 10b can be further prevented.

Further, according to the present embodiment, the total opening area of the through holes 13 of the most upstream heat exchanger 10a and the second heat exchanger 10b and the opening area of each through hole 13 are larger than those of the third heat exchanger 10c. It's also big. For this reason, the total area of the projection plane where the through holes 13 of the most upstream heat exchange body 10a are projected onto the second heat exchange body 10b, and the projection where the through holes 13 of the second heat exchange body 10b are projected onto the third heat exchange body 10c. The total area of each surface is larger than that of a projection surface obtained by projecting the through holes 13 of the third heat exchanger 10c onto the heat exchanger 10 on the downstream side thereof. Therefore, the total heat receiving area of the portion where the combustion exhaust flows through the through holes 13 of the most upstream heat exchange body 10a and collides with the second heat exchange body 10b, and the combustion exhaust flows through the through holes 13 of the second heat exchange body 10b. The total heat receiving area of the portion where the combustion exhaust gas collides with the third heat exchanger 10c is the total heat receiving area of the portion where the combustion exhaust flows through the through hole 13 of the third heat exchanger 10c and collides with the heat exchanger 10 on the downstream side. larger than the area. Moreover, the opening area of each through hole 13 of the most upstream heat exchange body 10a and the second heat exchange body 10b is larger than that of each through hole 13 of the third heat exchange body 10c.

The temperature of the combustion exhaust gas is determined by the heat generated between the water flowing in the internal space 14 of each heat exchanger 10 and the combustion exhaust gas while the combustion exhaust gas flows from the upstream side to the downstream side in the heat exchanger 1b. Exchange takes place and it goes down. On the other hand, when large through holes 13 are formed in the most upstream heat exchange body 10a, the heat receiving area of the most upstream heat exchange body 10a itself decreases. Therefore, due to the heat exchange between the water flowing in the internal space 14 of the most upstream heat exchanger 10a and the combustion exhaust, the heat transferred from the combustion exhaust to the most upstream heat exchanger 10a is reduced, and the upstream area of the combustion exhaust In this case, the temperature of the combustion exhaust gas is difficult to decrease. As a result, there is a possibility that the third heat exchange body 10c may be locally overheated by the combustion exhaust gas that flows through the through holes 13 of the second heat exchange body 10b and collides with the third heat exchange body 10c.

However, according to the present embodiment, the total opening area of the through holes 13 of the most upstream heat exchange body 10a and the second heat exchange body 10b and the opening area of each through hole 13 are respectively those of the third heat exchange body 10c. Since it is larger than , it is possible to prevent local overheating of the second heat exchange body 10b and the third heat exchange body 10c.

As described above, if the heat exchanger 1b is configured such that the upstream heat exchange group 9a includes the most upstream heat exchanger 10a to the heat exchanger 10 at a predetermined position downstream of the combustion exhaust gas flow path. , local heat can be effectively prevented not only in the second heat exchange body 10b adjacent to the downstream side of the most upstream heat exchange body 10a but also in the third heat exchange body 10c further downstream. Furthermore, according to the present embodiment, the water flow path is formed such that water flows in the same direction within the internal spaces 14 of the plurality of heat exchangers 10 in the upstream region of the combustion exhaust gas flow path. , the flow path resistance of water flowing within the internal space 14 of these heat exchangers 10 can be reduced. Thereby, even if the flow rate of water supplied to the heat exchanger 1b decreases, local heat can be prevented.

(Other embodiments)
(1) In the above embodiment, the internal space that is the flow path for the first fluid flowing inside each heat exchanger in the upstream heat exchange group is approximately the same as that of each heat exchanger in the downstream heat exchange group. It has an average height. However, the average height of the flow path of the first fluid flowing inside each heat exchanger in the upstream heat exchange group may be higher than that of each heat exchanger in the downstream heat exchange group. As a result, each heat exchanger in the upstream heat exchange group has a larger flow path volume of the first fluid than that in the downstream heat exchange group (for example, the first fluid flow path volume of each heat exchanger in the downstream heat exchange group 105-110% of the volume of the fluid flow path). That is, when the total opening area of the through holes of each heat exchanger in the upstream heat exchange group is increased, the flow path resistance of the first fluid flowing inside each heat exchanger in the upstream heat exchange group tends to increase. However, by increasing the volume of the first fluid flow path of each heat exchange element in the upstream heat exchange group, it is possible to suppress an increase in flow path resistance of the first fluid flowing inside each heat exchange element. Thereby, thermal efficiency can be improved.

(2) In the embodiment described above, one heat exchanger is formed with through holes having substantially the same opening area. However, through holes having different opening areas may be formed in one heat exchanger. Local heat tends to occur at a position away from the water passage hole where the first fluid tends to stay. For this reason, the through-holes of the upstream heat exchanger facing areas where local heat is likely to occur are formed large, and the through-holes of the upstream heat exchanger facing areas where local heat is difficult to generate are formed small. It's okay. In this way, by forming through holes of different sizes in one heat exchanger, local heat can be prevented while minimizing a decrease in thermal efficiency.

(3) In the above embodiments, the burner having a downward combustion surface is disposed above the heat exchanger. However, a burner with an upwardly directed combustion surface may also be arranged below the heat exchanger.

(4) In the above embodiment, a plurality of heat exchangers are stacked one above the other. However, the plurality of heat exchangers may be stacked on the left and right.

(5) In the above embodiment, a water heater is used, but a heat source device such as a boiler may also be used.

1, 1b, 1c heat exchanger 10 heat exchanger 10a most upstream heat exchanger 5 block 13 through hole 9a upstream heat exchange group 9b downstream heat exchange group

Claims (4)

A plate heat exchanger comprising a plurality of heat exchange bodies that perform heat exchange between a first fluid flowing inside and a second fluid flowing outside, and configured by stacking the plurality of heat exchange bodies. There it is,
The heat exchange body includes a plurality of through holes formed so that the second fluid flows outside the heat exchange body in a direction intersecting a flow path surface of the first fluid flowing inside the heat exchange body. has
Adjacent heat exchange bodies are formed such that a projected surface of the through hole of one heat exchange body does not overlap with the through hole of the other heat exchange body when viewed from the flow path direction of the second fluid,
Each heat exchanger in the upstream heat exchange group, including at least the most upstream heat exchanger located at the most upstream side of the flow path for the second fluid, is arranged downstream of the flow path for the second fluid in the upstream heat exchange group. The plate type is formed so that the total opening area of the plurality of through holes is larger than that in the downstream heat exchange group from the heat exchanger adjacent to the side to the most downstream heat exchanger located at the most downstream side. Heat exchanger. The plate heat exchanger according to claim 1,
The upstream heat exchange group is a plate heat exchanger including from the most upstream heat exchange element to a heat exchange element at a predetermined position on the downstream side of the flow path of the second fluid. The plate heat exchanger according to claim 1 or 2,
Each of the heat exchange bodies in the upstream heat exchange group is a plate heat exchanger that is formed so that the maximum opening area of the through hole is larger than that in the downstream heat exchange group. In the plate heat exchanger according to any one of claims 1 to 3,
Each of the heat exchangers in the upstream heat exchange group is formed such that the volume of the flow path for the first fluid is larger than that in the downstream heat exchange group.

Images