JPS6237687A - Heat exchanger - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plate-type heat exchanger, and more particularly to a heat exchanger in which cross-flow thermal contact occurs between fluids flowing through the heat exchanger.

Although heat exchangers are used for a variety of applications, they have been primarily developed for use in cooling and air conditioning.

Such applications require that the unit be made highly compact to reduce manufacturing costs, seemingly at odds with operating requirements. Heat exchangers have been developed to meet a variety of requirements, including the ability to use a variety of working fluids (gases, liquids, two-phase fluids, refrigerants, oils, water, and glycols), and to handle several kilowatts. The manufacturing development of heat exchangers has been carried out so that they can have capacities ranging from It's coming.

The document "Chemical Engineering" published in December 1974 (article "Graphite Heat Exchanger" on pages 80-83) describes a type of cross-flow thermal contact between fluids that is related to the content of the present invention. heat exchangers are described.

According to this article, a rectangular block-type cross-flow heat exchanger is constructed from a graphite plate, and two groups of parallel holes are provided inside the cross-flow heat exchanger so as to be perpendicular to each other. The graphite plates are joined together by a thermosetting resin, and the assembled block is maintained in compression between the plates by cast iron clamps. Headers are bolted to the four sides of the block, supplying and draining liquid to each group of holes in the block, and while the liquid passes through the holes.
Heat exchange takes place through the surrounding graphite block.

U.S. Pat. No. 1,662,870 also describes that a cross-flow type heat exchanger is constructed by a matrix of plates provided with orthogonal grooves. In this structure, a core is formed by bolting together a number of plates, and as in the case of the graphite heat exchanger described above, fluid flows between the headers bolted to the four sides of the core and each discharger.

The two conventional heat exchangers mentioned above are not designed to be compact, and although this can be improved by adopting modern assembly techniques, there are other problems with the conventional heat exchangers mentioned above. In any heat exchanger, the fluids cannot come into thermal contact with each other except when the fluids flow inside the core of the heat exchanger.

In this respect, the present invention has a contrasting structure,
As discussed below, one fluid is brought into thermal contact with the other fluid through the header wall, thereby reducing potential thermal stresses at the interface between the header and the core. ing.

Header or Manifold (collectively referred to as Header)
When installed in the core of a heat exchanger, the temperature of the header will, without appropriate measures, approach the temperature of the fluid flowing through it, whereas the temperature of the core will be at a value between the inlet temperatures of both fluids. Become. For this reason, when the core and the header fastening attachment part are rigid bodies (for example, when they are fixed by welding, brazing, or soldering), the difference in the amount of expansion between the header and the core causes the header and the core attachment part to Significant stress occurs in the vicinity of . This results in fatigue failure when ductile materials are used as the operating cycles increase, and instant failure when brittle materials are used.

The above problem becomes very serious when the inlet temperature of one of the fluids is far from the core temperature and the header is provided with heavy walls to withstand high fluid pressures.

Such a situation may occur if one fluid has a much lower heat capacity than the other fluid, resulting in large temperature changes while flowing through a heat exchanger, or if one fluid has poor heat transfer properties, e.g. This occurs when the heat transfer coefficient within the core is much lower than that of the other fluid.

In an oil cooler for a cooling screw compressor, for example, water cools the oil from about 90°C to about 50°C, which increases the temperature of the water from about 30°C to 35°C, but none of the above factors This applies to such oil coolers. Since water has a very high heat transfer property and its heat transfer is facilitated by turbulence, the heat transfer coefficient of water within the core is about 10 times that of oil.

Therefore, the core temperature is approximately 40°C or less in any part of the core, but the header, which carries oil to the inlet side of the core during starting and stopping operations, has a temperature of 50°C relative to the core.
Change. For this reason, an abnormally large stress may be applied to the attachment portion between the core and the header.

In order to solve the above problem, in the heat exchanger of the present invention, a plurality of flat metal plates are arranged in a stacked state and bonded to each other in surface contact by diffusion bonding to form a core. At least some of the plurality of plates are formed with a first group of grooves extending between a first pair of opposite edges of the plates; forming a second group of grooves disposed laterally to the plate, the second group of grooves extending between a second pair of opposite edges of the plate and not communicating with the first group of grooves; kept in good condition. The groove of each plate is formed with a depth smaller than the plate thickness, and the depth is set between 0.2zz and 1
．． Set within the range of 5m. First and second headers are joined to opposite edges of the core to provide fluid communication with the first group of grooves, and the first group of grooves are connected via the first and second headers. Means are provided for flowing the first fluid through the first fluid.

A container is provided for housing the core and first and second headers, the interior of the container being in fluid communication with the second group of grooves in the core.

means for flowing a second fluid into the second group of cores and the interior of the container, the second fluid contacting the outer surfaces of the first and second grooves within the interior of the container; is discharged from the inside of the container after coming into contact with the header.

Heat exchange between the first and second fluids occurs while the fluids flow through the core, and the first and second headers
The inner and outer surfaces are exposed to the first and second fluids, respectively. Therefore, the temperature of the core and header is between the temperatures of the two fluids, and is usually close to the temperature of the fluid with higher thermal conductivity. Since the values are close to each other, thermal stresses are significantly reduced. As the second fluid, it is preferred to carry a fluid with high thermal conductivity, in which case the core, header and container will be at similar temperatures.

If the Reynolds number is set high enough to induce turbulence in one or both groups of grooves, the grooves may be formed with zigzag, serpentine, or other curved passages; It is preferable to cause turbulence in the flowing fluid.

In either case, the strips preferably extend over the entire length or width of the board, and extend to the edge of the board, provided that longitudinally extending strips are not formed over the entire width of the board surface on which they are provided. , the laterally extending grooves are not formed over the entire length of the grooved plate.

Two groups of grooves can be formed on each plate, with a first group of grooves formed on one side of the plate and a second group of grooves formed on the other side. However, the width of the first group extending in the vertical direction is 1
It is preferable that the two types of plates are formed in a set of plates, the second group of arms extending in the lateral direction is formed in another set of plates, and the two types of plates are alternately arranged in a stacked state. In either case, a spacer plate may be provided between adjacent flat plates. If a spacer plate is used, its thickness should be 0.4xx to 1. It is preferable to set it in the range of Oxz.

Preferably, the thickness of each plate is formed by chemical or electrolytic processing. The thickness of the plate should be 0.0 mm below the grooves or between the grooves.
4ix~1. It is preferable to set the thickness so that a metal portion having a thickness in the range of Oxz remains.

The first fluid is supplied to and discharged from the core by the first and second headers, but when the core is exposed to the second fluid, the second driftwood is affected by inertia, buoyancy, and gravity. It is also possible to have two groups of grooves flowing.

However, in the embodiment of the present invention, a third header is fixed to one edge of the core, and the second group of fluids communicates with the third header, and the second fluid flows to the core through the third header. It is supposed to be done. Before or after passing through the core, the second fluid flows within the container, while contacting the outer surfaces of the first, second, and third hefters.

Both the first and second headers are in contact with the first and second fluids on their inner and outer surfaces, respectively, while the third header is in contact with the first and second fluids on both their inner and outer surfaces. and contacts only the second fluid. This is acceptable for the following reasons.

(1) Either the inner or outer surface of the second header contacts the second fluid after passing through the core.

(2) When heat conductivity is high, the temperature of the second fluid is usually close to the temperature of the core.

(3) The third header has a low differential pressure, so
It has a lighter construction than the first and second headers, and is less prone to thermal stress problems than the first and second headers.

(4) Even if fatigue cracks occur in the third header,
Since this does not result in mixing or loss of the two types of fluids, it is not a serious problem.

The header can be joined to each edge of the core by welding, brazing, or soldering.

Next, embodiments of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 1A, the core of the heat exchanger is provided with a stacked body 20 consisting of a large number of flat stainless steel plates. The plates are joined in surface contact with each other,
It is arranged between a pair of end plates 21 and 22. The plates are bonded at their contact surfaces by diffusion bonding, and when bonding is performed, the plates are pressed together and heated to a temperature close to the melting point of the metal, thereby promoting interfacial crystal growth. During the bonding process, the stack of plates is compressed by 0.5% to 5.0%, thereby ensuring the bonding condition and compensating for poor flatness of the plates, if any.

The laminate 20 has a structure in which two types of plates 23 and 24 are stacked alternately. One plate 23 is provided with a plurality of longitudinally extending grooves 25, each groove 25 being formed on one opposite side of the plate.
It extends between the paired (first pair) edges 26a, 26b.

The other plate 24 is formed with laterally extending grooves 27, each groove 27 extending between opposite edges 28a, 28b of the other pair of plates.

FIG. 2 shows a plate 23 having a longitudinally extending ridge 25, which extends at right angles to the edges 26a, 26b, and which extends across the entire width of the plate. A non-grooved edge 29 extends across, ie along both sides of the plate.

FIG. 3 shows a plate 24 with a laterally extending groove 27 extending over the entire width of the plate between edges 28a, 28b. However, the lateral grooves 27 are not provided along the entire length of the plate, but an unflanked edge 30 extends along both ends of the plate.

The width 25 of the plate 23 extends in a zigzag pattern, and its depth is smaller than the thickness of the plate. The plate 27 is linear and its depth is smaller than the thickness of the plate 24.

The grooves in the plates 23, 24 can be formed by simple grooves, the cross-sectional shape of which is shown in Figure 4A, or alternatively, the grooves can be shaped as shown in Figures 4B-D. You can also do that. That is, as shown in FIG. 4B, it is also possible to form a cusp 31 (thorn: protrusion) extending in the vertical direction in each groove,
As shown in FIG. 4C, a plurality of webs 3 continuous in the lateral direction
2t! - Can also be formed. In place of them, the fourth
As shown, a series of posts 33 may be left in each groove in an irregular manner to form a serpentine path for fluid flowing within the groove.

Metals 25 and 27 are formed by removing metal from a plate, and the removal is performed by chemical processing or electrolytic processing.

Metal parts that are not to be removed are protected by forming a mask (shielding object) by printing, screen printing, or photography (using photoresists 1 to 1) before exposing the surface to the processing medium. This method allows for the economical use of different materials for the core of the heat exchanger; in the present invention the plates are relatively thin;
Moreover, when the depth is shallow, aluminum, bronze, copper, brass, stainless steel, and other materials can be used economically.

When the first fluid used in the heat exchanger is water and flows through the grooves in the plate shown in Figure 2, and the second fluid is oil and flows through the grooves in the plate shown in Figure 3,
The dimensions of the plates 23 and 24 are set to, for example, a length of 450xx, a width of 70za+, and a thickness of 1.0xx. Groove 25゜2
7 has a width of 1.0 to 2. Ozz and depth 0.3
~0.611. The thickness of the end plate 21.23 is 1
0. Order Ozy.

As shown in FIG. 5, first and second headers 35, 36 are welded to opposite edges of the core, with fluid inlet and outlet conduits 37 connecting to the interior of each header. When the core is assembled into the finished heat exchanger, the fluid flows from the header 35 into the groove 25, and while flowing through the fluid 25, it exchanges heat with the second fluid flowing through the other fluid 27. It exits the core through a header 36.

The core structure shown in 2I is similar to the structure in FIG. Z+1
The difference is that fluid is sent to i427. Header 38 is supplied with fluid from conduit 39 .

The core shown in FIG. 7 is constructed similarly to the core of FIG. 6, except that the transverse grooves 27 allow fluid to flow in both directions. That is, a third header 40 (corresponding to header 38 in FIG. 6) is welded to the third t(!) portion of the core, the header 40 being delimited by portion 41 and inlet and outlet conduits 42,43. is the provision.

When the core is assembled into a completed heat exchanger, fluid flows into the groove extending in the transverse direction from the guide g42, flows from the stream to one end of the core, and then flows into the outer container (7 not shown). do. The fluid is placed in the container at header 35.38.4.
0 and then exits the conduit 43 through another group of streams 27. At the same time, another heat exchange fluid entering from the header 35 flows straight through the core and extends into the longitudinally extending
5 and is discharged from the core to the header 36.

The multi-passage structure shown in FIG. 7 can be used for the flow of both fluids, and the above structure can be used to form passages of 3 rgA or more for either or both of the fluids.

The core structures shown in Figures 5-7 are commonly used in different types of heat exchangers, some of which are described below with reference to Figures 10-13.

The heat exchanger core is most easily assembled by the method shown in FIG. 1, but the core can be constructed by various other methods. For example, the 8th [:! 2rvJ of the form shown in [11] by the bridge par 47 as shown in J.
The end portions of the cores 45 and 46 can also be connected. In this case, one heat exchange fluid flows through both cores 45, 46 in a longitudinal direction, as shown by arrow A in FIG.
The fA fluid enters the space between both cores and then splits into two flows in opposite directions, causing it to flow laterally through the cores 45,46.

If a large capacity heat exchanger is required and the total number of laminated plates is too large to be joined by the 11jU fY process, the core can be constructed as shown in FIGS. 9 and 9A. In this case, the core is formed of three sets of laminated plates 49, 50, and these laminated bodies are joined to each other via a spacer plate 60, for example, by welding.

In each stack, alternately arranged plates 49, 50 have grooves 25° 27 perpendicular to each other, as shown in FIG. 9A.
is formed. Their blank outlines are shown in dashed lines in FIG. The first heat exchange fluid is connected to arrows A1, A2 . A3
The second heat exchange fluid flows through the core in the direction shown by arrow Bl
, B2. It flows through the core in the direction indicated by B3.

The core of a composite structure can also be constructed by combining the structures shown in FIGS. 8 and 9.

A core of the type shown in FIG. 5 can also be incorporated into a finished heat exchanger as shown in FIG. 10, in which case the laterally extending grooves 27 of the core are arranged vertically. 10th
The illustrated heat exchanger is provided with a vessel 51 in which inlet and outlet conduits 52,53 are provided and the entire core is disposed inside the vessel 51.

The first heat exchange fluid is routed through conduit 37 to the core where it exchanges heat with the second fluid. The second fluid flows inside the vessel and thereby washes the outer surface of the header 35.36, so that the header 35.36 is in contact with both the first and second heat exchange fluid.

The heat exchanger shown in FIG. 10 is mainly used when the second fluid is at a saturation temperature in the container and boils as it flows upward through the core 20. The second fluid passes through the core once or more than once due to the effect of buoyancy during boiling, and the upstream and downstream levels of the fluid are separated due to the difference in gas-liquid richness. Therefore, no header is required to direct the heat exchange fluid to the grooves extending laterally (vertically) within the core.

The heat exchanger n4 structure shown in FIG. 11 is similar to the structure of FIG. 10, except that external pressure is required to flow the second fluid within the core.

In this case, the core 20 and the headers 35,36 form a baffle within the heat exchanger vessel 54. The first heat exchange fluid is supplied to the header 35 from the right side in the drawing.
flows into the core, flows to the left in the core, and flows out from the header 36. Due to the pressure difference on both sides of the core, the second heat exchange fluid
It flows upward in a lateral (vertical) course 27 within the core.

As with the embodiment of FIG. 10, in the tt4 construction of FIG. 11, headers 35,36 are exposed to both the first and second heat exchange fluids.

In the heat exchanger shown in FIGS. 12 and 13, a container 55 containing a core 20 has a cylindrical wall portion and a dish-shaped end cap 56.
This is the provision. The core is constructed as shown in FIG. 6, with opposed headers 35, 36 directing the first heat exchange fluid longitudinally relative to the core 20. A conduit 37 connecting to the header 35,36 passes through the end cap 56 and is adapted to convey the first heat exchange fluid to the heat exchanger.

The second heat exchange fluid is supplied by conduit 39 and header 38 to
Distribute to the core. After passing laterally through the core, the second heat exchange fluid enters the interior of the vessel 55 and enters the exhaust conduit S
7, it is carried out of the container. As the second heat exchange fluid passes through the core 20 and into the interior of the heat exchanger vessel, it contacts the outer surface of each header 35, 36, 38.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the core of a cross-flow plate heat exchanger, Figure 1A is an enlarged view of the plate of the core, and Figure 2 is a plan view of one plate of the core having longitudinal grooves. FIG. 3 is a plan view of the other type of plate having transversely extending grooves;
4A to 4D are cross-sectional views of different embodiments of the core provided on the plate of FIG. 3, and FIG. 5 is a cross-sectional view of the first and second (
6 is a perspective view of a heat exchanger core with headers welded to opposite edges); FIG. 6 is a perspective view of a structure similar to FIG. 5 with a further header attached to the third edge of the core; 7th I
2I is a plan view of t'RYH with the same structure as in Fig. 6 and a third header configured to form bidirectional flow, and Fig. 8 is a plan view of t'RYH using two laminates similar to Fig. 1. A perspective view of a two-element core spaced apart by spacer plates; FIG. 9 shows an alternative implementation with three separate longitudinal groove areas and three separate transverse groove areas; A perspective view of the example core, FIG. 9A is an enlarged view of the plate portion of the core in FIG. FIG. 11 is a schematic cross-sectional view of another embodiment in which a core is provided inside the container, FIG. 12 is a perspective view of a completed heat exchanger incorporating a core of the type shown in FIG. 6, and FIG. The heat exchanger shown in Fig. 12 is
FIG. 13 is a front sectional view taken along the 13IiIT plane. 20... Laminate 2], 24... Plate 25.27-
・-Lecture 26a, 26b, 28g, 28b-Edge 35.
36.38...Header 47...Bridge bar (connecting bar) 51...Container agent Patent attorney Terugai Ito 3 people AGB FIG, 2 FIG, 3FI
G, 4 FIG, 5 FIG, 6 FIG, 9 FIG, II

Claims (1)

[Claims] 1(a) A core is formed by arranging a plurality of flat metal plates in a stacked state and joining them to each other in surface contact by diffusion bonding,
at least some of the plurality of plates, the first
forming a first group of grooves extending between the pair of edges; forming in at least some of the plurality of plates a second group of grooves disposed transversely to the first group; The second group of grooves extends between a second pair of opposite edges of the plate and is kept in communication with the first group of grooves, and the grooves in each plate are formed to a depth less than the thickness of the plate. and reduce the depth to 0.2mm to 1.5m.
m, (b) first and second headers are joined to mutually opposite edges of the core to communicate with the first group of grooves in a state where fluid flows, and (c) the first and (d) providing a container for accommodating the core and the header, the interior of the container being connected to the second group of grooves in the core. (e) means for causing the second fluid to flow into the second group of grooves of the core and the inside of the container, so that the second fluid passing through the container flows into the inside of the container; (f) means for discharging the second fluid from the interior of the container after contacting the headers. 2. The second group of grooves are directly connected to the inside of the container, so that the second fluid flows from the inside of the container through the core to the inside of the container. Heat exchanger. 3 The core and the first and second headers separate the container into two
The heat exchanger according to claim 1, characterized in that the baffle plate is formed into two sections. 4. A third header is joined to one edge of the core and in fluid communication with the second group of grooves in the core to communicate a second fluid to the container through the third header and the core. Claim 1 characterized in that a conduit is provided for
Heat exchanger as described in Section. 5 Use two of the above-mentioned laminates of flat metal plates to form a core, incorporate into each laminate the plates in which the first and second groups of grooves are formed, and connect the two laminates with spacer rods. Join, 2
2. The heat exchanger according to claim 1, wherein fluid flows between a group of corresponding grooves in each laminate. 6. At least two of the above-mentioned laminates of flat metal plates are used to form a core, and each laminate incorporates a first and second group of grooved plates, and the first and second groups of grooves of each laminate are incorporated. 2. A heat exchanger according to claim 1, wherein both laminates are connected at their ends with the grooves of the groups being parallel to each other. 7. The heat exchanger according to claim 1, wherein the first group of grooves is arranged at right angles to the second group of grooves. 8. The heat exchanger according to claim 1, wherein the grooves of at least one of the first and second groups are provided in a non-linear manner. 9 The first group of grooves are formed in one set of plates, the second group of grooves are formed in another set of plates, and both sets of plates are arranged alternately in a laminated state. A heat exchanger according to scope 1.