FR2461222A2 - FLAT CONDUIT, IN PARTICULAR FOR EVAPORATOR - Google Patents

Abstract

THIS FLAT DUCT FOR HEAT EXCHANGER IS OF THE TYPE DESCRIBED IN THE MAIN PATENT AND INCLUDES TWO IDENTICAL PLATES 14 WHOSE EDGES ARE JOINED TO FORM A CIRCULATION ENCLOSURE FOR FLUID SUCH AS A REFRIGERANT BETWEEN THE INLET AND OUTLET MANIFOLDS PLATES. ROWS OF OBLIQUE RIBS 42 ARE SHAPED FOLLOWING A STAGE ARRANGEMENT IN EACH PLATE, BETWEEN THE COLLECTORS, IN ORDER TO PREVENT THE FORMATION OF LINEAR FLOW PATHS THROUGH THE ROWS BETWEEN THE TWO COLLECTORS. AT LEAST ONE BYPASS CHANNEL 60 GOES IN FRONT OF ONE END OF THE ROWS OF RIBS TO DECREASE THE FLOW RESISTANCE BETWEEN THE INLET AND OUTLET MANIFOLDS. APPLICATION TO EVAPORATORS USED IN AIR CONDITIONERS OF MOTOR VEHICLES.

Description

The present invention relates to heat exchangers of the type to

  The flat ducts are an improvement over the invention described in main patent No. 7915683, which discloses and claims a flat evaporator duct formed from two plates having edges joined together, and intermediate portions spaced apart one from the other. on the other side to delimit a chamber for the circulation of a refrigerant, the opposite ends of the plates

  with parts that are staggered or pushed out

  outside the plan of the intermediate parties in order to

  miter input and output manifolds and train

  staggered surfaces on adjacent flat ducts,

  designed to be assembled together, when the elements are stacked, to form

  air circulation between the adjacent intermediate parts

  flat ducts, characterized in that it comprises several rows of distinct ribs formed in the intermediate part of each plate, the

  ribs being arranged obliquely with respect to the length

  the width of the plates, each row comprising at least one whole rib and one rib having only a portion of the length of the rib, which is adjacent and

  in continuity with one edge of the plate, the ribs of each

  row overlapping and arranged with respect to the ribs of each row overlapping and being staggered with respect to the ribs of the same row and ribs of an adjacent row to prevent formation of a

  linear flow path through the rows of ribs

  res. The present invention is characterized in that

  the flat duct comprises several rows of ribs

  formed in the middle part of each

  that, the ribs being arranged obliquely relative to

  the length and width of the plates, the ribs

  killed at at least one end of each

  spaced apart from the edge of the plate to form a

  diversion channel passing in front of at least the said first

  at the end of the rows, at least some of the ribs of each row overlapping and being staggered relative to one another

  ribs of the same row and ribs of

  adjacent layer to hunt a linear flow through

  the rows, the inclined ribs of one of the plates

  tending across corresponding and adjacent inclined ribs of the other plate of the flat duct

  numerous points of contact, thus making a journey of

  mentally on the ribbed surfaces and the points of contact between and around these surfaces and

of contact.

  The invention provides a flat duct for exchanger

  which prevents linear flow of the fluid through

  to the rows between the inlet and outlet ports

  without increasing the resistance to flow in a manner

  ble, thus improving the efficiency of the heat exchange of the flat duct in comparison with the known flat ducts

  of the same size. This makes it possible to use a heat exchanger

  slimmer, lighter and less expensive. Compton

  given the current importance attached to the reduction of the

  weight and bulk in the new self-driving vehicles

  small dimensions, the characteristics of the con-

  flat duit are particularly important when used for example for the realization of the evaporator

  an air conditioning system for these vehicles.

  The flat duct according to the invention ensures a trans-

  very efficient heat mission through the use of a

  figuration with staggered or staggered ribs. This configuration

  staged ribs provides a partial flow path

  ticularly sinuous for the fluid but having many

  numerous flow paths. The distribution of the fluid on the

  width of the flat duct and inside the duct is also

excellent. -

  Other features and advantages of the invention

  will appear in the following description

  with reference to the accompanying drawings given by way of example only and in which:

  FIG. 1 is a plan view of a composite evaporator

  carrying a flat duct depicted with tearing progres-

  sif from left to right to show outer portions of the top plate and bottom portions of the bottom plate, these plates having a configuration according to the main patent; FIG. 2 is an elevational view of a plurality of stacked flat ducts forming part of the evaporator, viewed in the direction of the arrows 2-2 of FIG. 1; FIG. 3 is a partial view in section on a larger scale taken along the line 3-3 of FIG. 1; FIG. 4 is a sectional view of the evaporator taken from line 4-4 of FIG. FIG. 5 is a perspective view of the conduit plates, spaced apart so that their internal configuration is apparent;

  FIG. 6 is a plan view of a plate, of

  according to the invention; FIG. 7 is a plan view of a second mode

  embodiment of a duct plate according to the invention.

  Referring to FIGS. 1 to 5, it is shown

  flat ducts 10 each of which consists of

  12 and 14 having a configuration according to the main patent. It is shown in FIG. 2 two flat ducts

  and part of a third. The flat ducts 10 are

  crushed as shown in FIG. 2 in order to delimit between

  them an interval 16 for air circulation. Inter-

  Valve 16 normally contains an intermediate corrugated metal member 17 having fins 17 'formed by cutting to increase the efficiency of the heat exchange. For the sake of clarity only one part of a

intermediate element 17.

  Referring to FIG. 1, the plates 12 and 14

  are represented in their normal layout in which

  they overlap. The left side of the drawing shows

  the upper or outer surface of the upper plate

  12 while the right part of the same figure shows the inner surface of the plate 14. As seen in FIG. 5, the plates 12 and 14 are adapted to

  superimposed in mutual contact when they are available.

to be assembled.

  The individual plates 12 and 14 have an

  identical guration and, to superpose them to form a flat duct simply reverses the position of one of the plates by rotating 1800. Each plate has a flat peripheral edge 18 and the edges 18 of the two plates are shaped so to get in touch

  before being joined together by brazing. The parts

  intermediates 20, 22 of the plates 12 and 14 are pushed up and down respectively with respect to the edges 18. Thus when the edges 18 are in contact with the

  planes containing the intermediate parts 20, 22 are spaced

from each other.

  A fluid such as a refrigerant for the use of

  evaporation is introduced into the flat duct

  at one end and is evacuated through the other end. Colleges

  input and output readers 24, 26, for the flat duct are formed by portions 28 of the plates 12 and 14 which are pushed outward and present in their

  together a circular shape. Each plate 12 and 14 pre-

  feels a repelled portion 28 at each end. An opening

  30 is provided in the upper surface at one end.

  tee, and an opening 32 is provided at the other end -e-

  a rim 34 projecting outwards. So the plates

  are shaped so that the flange 34-entc -rant lDuvert--

  32 is adjusted in opening 30. This ensures the coincidence

  between the plates of two different ducts, as shown in FIG. 2. Then the flat ducts are

  soldered together to form an evaporator, one of which

tie is shown in FIG. 2.

  At one end of a plate, in the vicinity of the

  3 and slightly outwardly relative to the flat edge 18, is formed a rim 36 shifted upwards. Similarly, outside of part 18, the plate edge is normally bent upwards from the

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  surface of the flat edge 18, along the lateral edges 38. This

  it contributes to the rigidity of the plate.

  To ensure a uniform distribution of the fluid

  in the flat duct, four channels 40 are formed as

  shown in FIGS. 1 and 4. The channels 40 allow the fluid to pass intake manifolds 24 in the intermediate portions delimited between the intermediate surfaces, 22 of the plates 12 and 14. Likewise analogous channels

  41 at the right end of the flat duct

  in FIG. 1 allow the fluid to flow into the

outlet manifold 26.

  Fluid flow through the inter-

  mediates of the flat duct between the pushed surfaces 20, 22 is oriented by a particular non-planar configuration of the intermediate surfaces 20, 22. The surfaces 20, 22 are offset or pushed relative to the plane containing the edges 18, in the same direction as the collectors 28, but they are not strictly flat and have a particular configuration to ribs comprising a plurality of spaced relatively short spaced ribs 42 constituting cavities,

  ribs protruding downwards from the sur-

  faces 20 and 22 in opposite directions with respect to parts 28.

  The ribs 42 are constituted by relative impressions

  in the intermediate part and pre-

  sensing in the embodiment shown a length

  which is approximately one third of the width of the con-

  flat duit. The ribs are aligned to form rows

  which are designated A, B and C in FIG. 1. The evapo-

  fully represented model has about 19 rows

  in each flat duct. Footprints or cavities 42, de-

  signed in the following by "ribs", are inclined

  in each row in relation to what would be the axis of

  Directly between the collectors 24, 26 as seen in FIG. 1. Opposite orientation of ribs 42

  in the two plates of the same flat duct spring

  Figs. 1 and 5. This angular orientation of the nerves

  in opposite directions results from the inversion of the posi-

  one of the plates during assembly. As indicated above, a plate is inverted or reversed and rotated 1800 relative to the second plate before their

  assembly. Thus, the orientation of the ribs 42 is reversed.

  See. As a result of this reversal of the position of the plate the ribs of a plate intersect with the corresponding ribs of the other plate. When the many points of contact between the entrenched veins have been

  brazed, many flow paths are formed through

  to the veins and around them. It will be noted that

  all the intermediate surfaces 20 and 22 are in contact

  mutual tact in a flat duct the plates are brazed together. These points of contact are designated by X at the

Fig. 3.

  The particularly advantageous arrangement of the nerves

  in each row is of great importance to

  the width of the flat duct without impairing the efficiency of the heat exchange. Considering more particularly the right end of the flat duct shown in FIG. 1, which shows a portion of the bottom plate 14, the row comprises five integral ribs 42a-e. At each end of the row are formed ribs 42f and g having only a portion of the length of the ribs 42a-e. These parts

  of rib connected to the edge 18 of the plate 12. The

  the trenches of ribs 42f and 429 and the next adjacent rib 42 are interposed between each other or are staggered or staggered, as seen along the line

  linear flow between the collectors 24, 26.

  the fluid flowing from the collector 24 to the collector

  26 follows at least a portion of the ribs 42 before contouring.

  a point of contact X brazed, then the flow meets

  another rib in an adjacent row, and so on.

  Thus the fluid describes zig-zags through the volumes indi-

  intermediaries formed between parts 22 and 20 rather than

  flow in a straight line through these parts. This increases

  This greatly increases turbulence and improves the efficiency of heat exchange without undesirably increasing the flow resistance of the fluid. The efficiency and the distribution of the fluid over the width of the flat duct are further improved by the formation of the ribs 42f and 42g having only a part of the length of the others and which in conjunction with the entire ribs 42a to 42e provide a flow fluid at the edges 18 of the duct, and so

  a very uniform distribution of the flow.

  When the evaporator is used in a

  air conditioning system of a motor vehicle, a

  casing having air inlet and outlet ports op-

  posed contains the heat exchanger. The air then passes through the gaps 16 and passes on the intermediate element 17 and on the fins 17 'thereof. Means comprising elastic seals carried by the housing (not shown)

  are in contact with a surface along one and the other

  end of the evaporator as will be described later. Projections or lugs 44 came from matter

  with the plates 12 and 14 in the vicinity of the parts 28 in

  me of collectors. The tabs 44 comprise a portion 46 which is coplanar with the edge 18 and portions 48, 50, which are perpendicular thereto. It is also planned a

  part 52 parallel to part 46. The legs 44 are

  killed at one and the other end of the face of

  evaporator as shown in FIG. 1. The line

  parts 48 and 50 when the evaporator is assembled

  and that the flat ducts are brazed together form a bar-

  rage to block the flow of air around the parts

  repulsed 28 forming collectors. Without this blocking of the

  In the air, efficiency decreases and in some cases

  It has been found that the temperature of the outgoing air can increase by about 1.10C. The abutment of the parallel portions 52 contributes to fixing the elements and filling the gap between the flat ducts forming

surfaces that can be brazed.

  In the embodiment described above of the flat ducts, an improved transfer efficiency is obtained.

  without causing a high pressure drop.

  between the inlet and outlet ports due to

  the particular arrangement of ribs in which an ear

  Linearly linear is prevented: around rows of ribs as well as across them. It has also been found that improved heat transfer efficiency can be achieved with even lower pressure drop between the inlet and outlet ports by providing a branch passage at one end of staggered rib rows as shown in FIG. the embodiment of FIG. 6, and also by making a bypass duct to both

  ends of the staggered rib rows as well as a

  less sinuous jet across rows of ribs like

  shown in the embodiment of FIG. 7. We understand

  takes plates identical to the respective plates

  presented are stacked as in the embodiment

  Figs. 1 to 5 and as described above in detail for

  one or more flat ducts, and as a result,

  presented a single plate in FIGS. 6 and 7. In addition, in these FIGS. 6 and 7, similar references have been used but with a prime index (P) or a second ("), respectively, to denote the parts similar to those of FIGS 1 to 5, while the different parts are denoted by

new references.

  Referring to FIG. 6, there is shown a lower plate variant 14 'having protruding tabs 44' and which cooperates with an upper plate (not shown) which is identical but inverted and rotated with respect to the first and is then stacked on it. to form a flat duct and dams for air. As in the embodiment of Figs. 1 _ L the

  plate has an intermediate portion 22 'which is

  downwardly with respect to the edge 18 ', the inlet and outlet manifolds of the flat conduit being formed by portions 28' pushed outward and generally having a circular shape, which are formed in

  opposite ends of the plate. An opening 30 'is pre-

  seen in the upper surface at one end, and one

  Verture 32 'is provided with a flange 34' projecting outwardly at the other end. In addition, he is again

  provided four channels 40 ', 41' at each end in order to

  put fluid to pass between the collectors and the sur-

  intermediate face 22 'of the plate. In addition, it is also

  provided a configuration of offset ribs comprising

  several relatively short and spaced ribs 42 'which

  lie on the surface 22 '. The ribs are aligned in rows in the flat duct as in the embodiment of Figs. 1 to 5, the ribs of each row being angled obliquely with respect to the direct flow path between

  the collectors. In this example again, each of these

  consists of five whole veins 42'a to 42'e and two

  shorter vets; however, in this case, only the rib

  42'f at one end of each row is

  connected to the adjacent edge 18 'of the plate at the corresponding ends of the rows. On the other hand, the rib more

  42'h at the opposite end of each

  is not connected to the adjacent edge 18 'so as to

  on the contrary, a bypass channel 60 which passes in front of the corresponding end of all rows of ribs

  to directly connect the input and output collectors

  tie. Thus, the channel 60 provides a bypass flow with respect to the serpentine fluid paths formed by the ribs, which otherwise remain unchanged from those described in the embodiment of FIGS. l to 5. By

  following, almost all the winding paths of flui-

  of this embodiment are retained, but with the additional single bypass channel 60 passing in front of one end of the rows, resulting in a lower pressure drop due to the limited but direct flow path of the fluid between the entrance openings

and output.

  The plate 14 "shown in Fig. 7 has an even lower pressure drop between the inlet ports

  and output, in comparison with the previous embodiments

  teeth, while maintaining the offset arrangement of the ribs

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  comprising ribs 42 "to 42" e which provide sinuous fluid flow paths to achieve improved heat transfer efficiency. In this example, no

  short end ribs 42 "i and 42" j of each run.

  It is connected to the adjacent edge 18 "of the plate, so that there are thus formed bypass channels 62 and 64 which pass in front of the two opposite ends of the rows of

  ribs between the inlet and outlet ports,

  parison with the single channel 60 bypass provided in the example of flat duct FiG. 6. In addition, in a

  row on two, the central vein is divided into two nerves

  partial lengths 42 "k and 42" 1, so that the offset of the ribs is less in the middle of the rows and

  that a less sinuous fluid flow path is achieved

  through the middle of the rows between the

trea and out.

  In the particular arrangement shown, and with 19 rows in this example, direct flow across the middle of nine of the rows is prevented by their ribs.

  42 "c, while the flow may occur

  across the other rows in the interval between

  paranting these central veins, between the face-to-face ends

  partial center ribs 42 "k and 42" 1 of these other rows and face-to-face ends of ribs

  entire 42 "b and 42" d rows on either side.

  This less interrupted flow path through the middle of the rows, which is thus obtained in the exemplary embodiment of the flat duct of FIG. 7, can thus be designated as a median bypass interrupted between the inlet and outlet ports compared to the channels

  bypass 62 and 64 with open ends which pass

  the ends of the rows. It is furthermore understood that although the interruption is formed in every other row, fewer interruptions may be provided, which would further reduce the pressure drop. Otherwise,

  more interruptions may be expected when

  it is desired to obtain a more sinuous flow path for the fluid in order to obtain a higher yield of

- - Have.

  heat transfer rather than a decrease in the fall

pressure.

  The technicians will thus notice that with the above embodiment of the flat duct according to the invention, it is possible to precisely adapt the flat ducts to the desired heat transfer efficiency and to the pressure drop permitted according to the invention. special application

  which is made of the heat exchanger.

246 1222

Claims (4)

  1. Flat duct for heat exchanger, formed of two plates having edges joined to one another, and   intermediate parts spaced apart from one another in order to   miter a chamber for the circulation of a fluid, the extremes   opposite sides of the plates having offset parts or   pushed outward from the plane of the intermediate parts   in order to define inlet and outlet manifolds and to form offset surfaces on adjacent flat ducts, intended to be joined together when the elements are stacked, to form passages   air circulation between adjacent intermediate parts   flat ducts according to the main patent, characterized in that it comprises-several rows of distinct ribs   (42 ', 42 ") formed in the middle part of each   that (12, 14), the ribs being arranged obliquely with respect to   port to the length and width of the plates, ribs   at least one end of each of the rows   spaced apart from the edge (18) of the plate to form a bypass channel (60, 62-, 64) which passes in front of at least said first end of the rows, at least some of the ribs of each row overlapping and being stepped compared to the veins of the same row and to the ribs of the   adjacent row to prevent linear flow through   to the rows, the inclined ribs of one of the plaquax extending across the corresponding inclined ribs and adjacent to the other plate of the flat duct forming   numerous points of contact thus achieving a flow of   sinuous on the ribbed surfaces and the points of   tact between and around these surfaces and touch points   2. Flat duct according to claim 1,   characterized in that the short ribs (42h) located at the ex-   opposing trenches of each row are connected to the adjacent edge   cent (18 ') of the plate, so that is delimited a channel (60) bypass directly connecting the inlet manifolds and Release. 2 46 1222   3. Flat duct according to claim 1, characterized   in that none of the short ribs (42 "i, 42" j) at both ends of each row are connected to the edge   adjacent (18 ") of the plate (14"), so that they are deli-   two channels (62, 64) of bypass connecting directly   the inlet and outlet manifolds.   4. Flat duct according to claim 3, characterized   characterized in that, in every second row, the central rib   trale is divided into two ribs (42 "k 42" 1) having only a portion of the length of an entire rib, thereby defining a less sinuous path for the flow of fluid through   the middle of the rows between the inlet and outlet ports tie.