Heat exchanger

Abstract

Two or more cores (2a, 2b) in each of which two more types of passage layers through which two or more fluids flow are layered alternately are welded together. The entire bottom portions of the cores (2a, 2b) are covered with a lower header tank (3), thereby making the fluids flow into the cores (2a, 2b). A dummy layer (14) through which none of the fluids flow is provided beside a weld side face of each core (2a, 2b). A weld spacer (18) is welded to the entire peripheral edge of a side plate (16) of the dummy layer (14). A through-hole (16a) for draining water in the dummy layer (14) is made near the lower end of the side plate of the dummy layer (14). Further, a liquid drain hole (20) through which water is drained is made at a lower corner of the weld spacer (18).

Claims

1. A heat exchanger including two or more cores welded together and each including two or more types of passage layers which are layered alternately and through which two or more fluids at different temperatures flow, the heat exchanger comprising: a lower header tank which entirely covers bottom portions of the cores and makes the fluids flow into the cores; a dummy layer which is provided at least beside a weld side face of each core, and through which none of the fluids flow; a weld spacer which is fixed to a peripheral edge of a side plate of the dummy layer; a through-hole which is made near a lower end of the side plate of the dummy layer, and through which liquid in the dummy layer is drained into a space defined by the weld spacer; and a liquid drain hole which is made at a lower corner of the weld spacer, and through which the liquid in the space is drained.

2. The heat exchanger of claim 1, wherein: the weld spacer is comprised of a plurality of bar-like members, and the liquid drain hole is implemented as a clearance between two of the plurality of bar-like members.

3. The heat exchanger of claim 2, wherein: the liquid drain hole is made between obliquely-cut tips of the two of the plurality of bar-like members, and the liquid drain hole extends toward a lower corner of the core.

4. The heat exchanger of claim 1, further comprising a cylindrical member that is fixed to an outer peripheral edge of the liquid drain hole, wherein an inside of the cylindrical member communicates with the liquid drain hole.

5. The heat exchanger of claim 1, further comprising a cylindrical member that is capable of receiving a plugging member which is detachable and capable of plugging the liquid drain hole.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an enlarged view showing the portion denoted by reference character I in FIG. 2.

(2) FIG. 2 is a perspective view showing a heat exchanger according to an embodiment of the present invention.

(3) FIGS. 3A and 3B are a front view and a side view of a heat exchanger, respectively.

(4) FIG. 4 is a perspective view showing a core.

(5) FIG. 5 is a side view showing a first passage layer.

(6) FIG. 6 is a side view showing a second passage layer.

(7) FIG. 7 is a side view showing a third passage layer.

(8) FIG. 8 is a side view showing a dummy layer.

(9) FIG. 9 is an enlarged cross-sectional view taken along the plane IX-IX in FIG. 1.

(10) FIGS. 10A and 10B are cross-sectional views corresponding to FIG. 1, and each show a configuration of a weld spacer according to another embodiment.

DESCRIPTION OF EMBODIMENTS

(11) Embodiments of the present invention will be described below with reference to the drawings.

(12) FIGS. 2 and 3 show a heat exchanger 1 according to an embodiment of the present invention. This heat exchanger 1 is implemented, for example, as a plate-fin-type heat exchanger 1 that is mainly made of an aluminum alloy. As shown in FIG. 4, the heat exchanger 1 of this embodiment includes two cores 2a and 2b. In each of the cores 2a and 2b, two or more types of passage layers through which two or more fluids at different temperatures flow are layered alternately. The cores 2a and 2b are welded to each other. The bottom portions of these cores are covered almost entirely with a lower header tank 3, and the top portions of the cores are covered almost entirely with an upper header tank 4. To side faces of the core 2, four side-header tanks 5 and 6, in total, are coupled, for example.

(13) Each of the cores 2a and 2b includes three types of fluid passage layers, for example. FIG. 5 shows a first fluid passage layer 11. As shown in FIGS. 2 and 3, a fluid A flows through the first fluid passage layer 11 from the upper header tank 4 to the lower header tank 3. The first fluid passage layer 11 includes, at each of its upper and lower ends, a distributer portion 11a which extends vertically. The first fluid passage layer 11 further includes a heat-transfer fin portion 11b which extends vertically between its upper and lower ends. For the sake of convenience, in the drawings, the intervals between the passages are wider than the actual ones and simplified. FIG. 6 shows a second fluid passage layer 12. As shown in FIGS. 2 and 3, a fluid B flows through the second fluid passage layer 12 from one of lower side-header tanks 5 that is on a side face of the core to one of upper side-header tanks 6 that is on the opposite side face of the core. The second fluid passage layer 12 includes, at each of its upper and lower ends, a distributer portion 12a which extends obliquely. The second fluid passage layer 12 further includes a heat-transfer fin portion 12b which extends vertically between its upper and low ends. FIG. 7 shows a third fluid passage layer 13. As shown in FIGS. 2 and 3, a fluid C flows through the third fluid passage layer 13 from the other one of the lower side-header tanks 5 that is on another side face of the core to the other one of the upper side-header tanks 6 that is on the opposite side face of the core. The third fluid passage layer 13 includes, at each of its upper and lower ends, a distributer portion 13a which extends obliquely. The third fluid passage layer 13 further includes a heat-transfer fin portion 13b which extends vertically between its upper and low ends. In each of the cores 2a and 2b, these three types of passage layers 11, 12, and 13 are layered one on the other. The three different fluids A, B, and C are at different temperatures, and heat is exchanged between the different fluids that are at different temperatures and passing through the adjacent ones of the fluid passage layers. For example, the fluids may be air at a temperature below the freezing point, nitrogen, oxygen, argon or other substances that are obtained by low temperature separation of air.

(14) FIG. 8 shows a dummy layer 14 through which no fluid flows. The dummy layer 14 forms each of the right and left outer layers of the cores 2a and 2b. As shown in FIG. 9 that is an enlarged cross-sectional view, the fluid passage layers 11, 12, and 13 and the dummy layer 14 are formed in the following manner: Corrugated fins 15 that have been formed and cut are each sandwiched between tube plates 19 together with a brazing filler (not shown), and an outer side of each of the dummy layers 14 is covered with a side plate 16, and thereafter, the layered components and side bars 17 are subjected to vacuum brazing. At this time, the corrugated fins 15 are formed and brazed such that its height and pitches are kept highly uniform. The brazing filler may be, in advance, rolled on and integrated with the tube plates 19 made of an aluminum alloy. A portion of predetermined ones of the side bars 17 of each passage layer are cut off to allow the associated fluid to pass, thereby establishing communication with the associated header tank. All of the four side bars 17 of each dummy layer 14 are continuous. Although each dummy layer 14 may include no corrugated fins 15, the corrugated fin 15 is usually provided to extend vertically in each dummy layer 14 in order to ensure the strength.

(15) The order in which the fluid passage layers 11, 12, and 13 are layered is not particularly limited. However, as shown in FIG. 9, in each of the cores 2a and 2b, the side plate 16, the tube plate 19, the dummy layer 14, the tube plate 19, the third fluid passage layer 13, the tube plate 19, the second fluid passage layer 12, the tube plate 19, the first fluid passage layer 11, the tube plate 19, the third fluid passage layer 13 . . . are layered in this order from one end. The dummy layer 14, the tube plate 19, and the side plate 16 are also arranged toward the other end. The configuration of these fluid passage layers 11, 12, and 13 is not particularly limited. Only two types of fluid passage layers or four or more types of fluid passage layers may be arranged. The type of flow directions in which the fluids flow are not particularly limited, but may be a cross flow type in which the flows are perpendicular to each other, a counterflow type in which the flows are opposite to each other, or a combination of these types. The configurations of the header tanks may be suitably altered in accordance with the fluid passages layers. For example, the side-header tanks 5 and 6 may be omitted or positioned differently from this embodiment. For example, if no side-header tanks 5 and 6 are provided, each of the lower header tank 5 and the upper header tank 4 may be divided into two sections.

(16) As shown in FIGS. 1 and 4, a weld spacer 18 is welded, in a frame shape, to the entire peripheral edge of one of the side plates 16 of the two dummy layers 14 that face each other. This weld spacer 18 is made of a plate of an aluminum alloy having a predetermined thickness, for example. The frame-shaped weld spacer 18 defines a space S between the two side plates 16.

(17) On the other hand, at least one through-hole 16a is made near the lower end of each of the side plates 16 that are provided on the weld sides of the cores 2a and 2b facing each other. The liquid, i.e. water, in each dummy layer 14 can be drained through the associated through-hole 16a.

(18) The weld spacer 18 has, at its lower corner, a liquid drain hole 20 through which water that has flowed into the space S defined by the weld spacer 18 is drained. This liquid drain hole 20 is positioned between obliquely-cut tips 18a of two bar-like members which constitute the weld spacer 18 and which extend perpendicularly to each other. In this manner, the liquid drain hole 20 can be made simply by obliquely cutting the tips 18a of the two bar-like members.

(19) Further, a cylindrical member which is implemented as a hollow cylindrical plug-receiving boss 21 is fixed to the outer peripheral edge of the liquid drain hole 20. The plug-receiving boss 21 suitably has a hollow structure to ensure the communication with the liquid drain hole 20, and its cross section is not limited to any particular shape. To this plug-receiving boss 21, a plugging member for plugging the liquid drain hole 20, which is implemented as a plug 22, can be attached. The plug 22 is not particularly limited, as long as the plug 22 is capable of plugging a liquid drain hole made in the boss. The plug 22 may be screwed or pressed into the boss.

(20) The plug-receiving boss 21 is welded when the two cores 2a and 2b are welded to each other. Specifically, the weld spacer 18 is welded to the side plate 16 of one core 2a, first. At this time, no weld bead W is formed in the portion that is to serve as the liquid drain hole 20.

(21) Thereafter, the weld spacer 18 is brought into contact with, and welded to, the side plate 16 of the other core 2b. Also at this time, no weld bead W is formed in the portion that is to serve as the liquid drain hole 20. The plug-receiving boss 21 is then fitted into the liquid drain hole 20, and the outer periphery of the plug-receiving boss 21 is welded. It is also possible that another weld spacer 18 is welded to the other core 2b in advance, and the two weld spacers 18 are brought into contact with, and welded to, each other such that the gap between their outer peripheries is filled.

(22) Thereafter, the lower header tank 3 and the lower side-header tanks 5 are welded. Consequently, weld beads W formed at this time are not allowed to plug the liquid drain hole 20.

(23) As can be seen from the foregoing, the plug-receiving boss 21 that is provided and welded to the liquid drain hole 20 prevents the liquid drain hole 20 from being filled with the weld beads W, thereby ensuring the drainage of liquid. When the welding is performed, the plug-receiving boss 21 ensures the communication with the liquid drain hole 20, which makes the welding easy and increases the workability significantly.

(24) In the thus configured heat exchanger 1, the presence of the dummy layers 14 prevents the fluid passage layers 11, 12, and 13 from being damaged during, e.g., the handling of the cores 2a and 2b when they are subjected to vacuum brazing or welding.

(25) Since no fluids flow through each dummy layer 14, the periphery of each dummy layer 14 is covered with the side bars 17 almost hermetically. In this regard, if the periphery of each dummy layer 14 was covered perfectly hermetically, inconvenience would be caused when vacuum brazing is performed or when the internal pressures of the cores 2a and 2b need to be released, for example. Therefore, a clearance of some kind is provided in the periphery, which allows water to accumulate in the dummy layer 14 when a pressure test is conducted using water or when condensation occurs, for example. As indicated by the arrows in FIG. 1, such water is drained through the through-hole 16a provided near the lower end of each side plate 16, and flows into the space surrounded by the weld spacer 18 provided between the two cores 2a and 2b.

(26) With the plug 22 detached, the water can be drained through the liquid drain hole 20 made at the lower corner of the weld spacer 18. In order to drain the water with more reliability, the heat exchanger 1 may be tilted. Thus, no water is allowed to remain to be frozen even if the fluids A, B, and C that are at temperatures below the freezing point are made to flow through the heat exchanger 1.

(27) When no water needs to be drained, the plug-receiving boss 21 is plugged with the plug 22. This allows for preventing foreign substances from entering the heat exchanger 1, thereby maintaining the quality of the heat exchanger 1.

(28) As described above, in the heat exchanger 1 according to this embodiment of the present invention, the through-hole 16a through which water in the dummy layer 14 is drained is made near the lower end of the side plate of the dummy layer 14, and the liquid drain hole 20 through which the water that has flowed out of the through-hole 16a is drained is made at the lower corner of the weld spacer 18. Thus, with this simple structure, the water in the dummy layer 14 can be drained with reliability. The present invention effectively allows for preventing the heat exchanger 1 from being damaged by frozen water.

(29) The heat exchanger 1 according to this embodiment is implemented as a plate-fin-type heat exchanger. Therefore, the tube plates 19 serve as a primary heat-transfer surface, and the corrugated fins 15 brazed between the tube plates 19 serve as a secondary heat-transfer surface and a reinforcing member against an internal pressure.

(30) (Other Embodiments)

(31) The heat exchanger of the above embodiment of the present invention may be configured as follows.

(32) In the above embodiment, the tips 18a of the bar-like members of the weld spacer 18 are obliquely cut to make the liquid drain hole 20. However, as shown in FIG. 10A, it is possible that the lower horizontal bar-like member of the weld spacer 18 is not cut, while the right vertical bar-like member of the weld spacer 18 is shortened to produce a clearance 18b. This clearance 18b may be used to make a liquid drain hole 20. This configuration is advantageous when no lower side-header tank 5 is provided at the lower end of the core 2. Alternatively, as shown in FIG. 10B, it is possible that the right vertical bar-like member of the weld spacer 18 is not cut, while the lower horizontal bar-like member of the weld spacer 18 is shortened to produce a clearance 18c. This clearance 18c may be used to make a liquid drain hole 20. This configuration is advantageous when the lower header tank 3 is displaced inward. In each case, it is preferable to provide a plug-receiving boss 21. Thus, these simple structures in which the clearances 18b and 18c are produced between the bar-like members that constitute the weld spacer 18 allow for draining, through the clearances 18b and 18c, the water that has flowed from the dummy layer 14.

(33) Though the above embodiment includes only one liquid drain hole 20, another liquid drain hole may be made at the opposite corner.

(34) Though the heat exchanger 1 of the above embodiment is made of an aluminum alloy, the heat exchanger may be made of other metals, such as a stainless alloy.

(35) In the above embodiment, the plug-receiving boss 21 is provided to prevent the beads W from plugging the liquid drain hole 20. However, the plug-receiving boss 21 does not have to be provided, and welding may be performed such that the liquid drain hole 20 is not plugged and is made to communicate with outside air. In such a case, a plugging member of some kind may also be provided detachably.

(36) The foregoing embodiments are merely preferred examples in nature, and are not intended to limit the scope, applications, and use of the invention.

INDUSTRIAL APPLICABILITY

(37) As described above, the present invention is useful for a heat exchanger including two or more cores welded together and each including two or more types of passage layers which are layered alternately and through which two or more fluids flow.

DESCRIPTION OF REFERENCE CHARACTERS

(38) 1 Heat Exchanger

(39) 2 Core

(40) 3 Lower Header Tank

(41) 4 Upper Header Tank

(42) 5 Lower Side-header Tank

(43) 6 Upper Side-header Tank

(44) 11 First Fluid Passage Layer

(45) 12 Second Fluid Passage Layer

(46) 13 Third Fluid Passage Layer

(47) 14 Dummy Layer

(48) 15 Corrugated Fin

(49) 16 Side Plate

(50) 16a Through-hole

(51) 17 Side Bar

(52) 18 Weld Spacer

(53) 19 Tube Plate

(54) 20 Liquid Drain Hole

(55) 21 Plug-receiving Boss (Cylindrical Member)

(56) 22 Plug (Plugging Member)