FR2782553A1 - EVAPORATOR - Google Patents

Abstract

The invention relates to refrigeration installations. This evaporator comprises a stack of plates (2) forming tubular elements and each composed of two sheets (4, 5) enclosing a cavity. Near at least one end of the plates (2) is provided a stamping (6, 7) for application against the adjacent plate (2). To the sheets (4, 5) of the end plates (8, 9) of the stack are fixed connection elements (15, 16) having a flat side directed towards the sheets and a recess provided in this side and which are deformed segments a connection tube (12, 13) which leads to a flange (14) carrying a regulator. Each tube (12, 13) is in one piece over its entire length, including on the connection element (15, 16), and is assembled to the flange (14) by a mechanical connection. Main applications: installations for vehicle air conditioning

Description

The invention relates to an evaporator for a refrigeration installation.

  compression, in particular for a motor vehicle air conditioning installation, comprising several plates gathered in a stack, which constitute tubular elements and are each composed of two sheets which enclose a cavity between them and on which it is provided, close to '' at least one end of the plates, a deep-drawn intended to be applied against the adjacent plate, and provided with openings for the passage of the coolant, while at the plates of the end plates of the stack, are fixed connecting elements having a flat side directed towards the sheets and a recess provided in this side and ribs arranged in each interval between

two adjacent plates.

  In document EP 0 590 306 A1, an evaporator is described for an air conditioning installation of a motor vehicle. This evaporator is made up of a stack of assembled plates, each plate being made up of two superimposed sheets, which enclose a cavity between them and thus form tubular elements. The plates are provided at one of their stamped ends to the right of which the adjacent plates are applied. In these stampings are openings for the passage of the coolant from one plate to the next. On the end plates of the stack, there are connection elements for a coolant inlet pipe and for a hot gas return pipe,

  and to these connection elements are welded connection tubes

  with free ends fitted with connecting nipples

for other tubular conduits.

  In the known evaporator, the stack made up of plates, with interposed corrugated ribs, is provided with side plates and connection parts and then brazed. In a new brazing operation, the connection tubes must be brazed in the connection elements, which requires reheating the connection elements. This work carried out in several stages does not lead

  only to an increase in the expenditure of time but, in addition

  ment, it can also lead to a deterioration of the structure of the material and of the brazed assemblies between connection element and end plate. The present invention aims to create an evaporator of the kind

  in question that could be made more economically.

  This problem is solved by an evaporator characterized in that the connection elements consist of deformed segments of a connection tube which extends to a flange of a pressure reducer, the connection tube being formed in one piece , including the connecting element, and being assembled to the flange by

a mechanical connection.

  The essential advantages of the invention reside in the fact that the evaporator, including the connection tubes, can be produced in complete brazing and that any zone of assembly of tube sections between the connection part and the regulator flange. The free ends of the connection tubes are assembled to the flange by a mechanical connection, so that no other heat treatment

is not necessary.

  According to a preferred development of the invention, there are provided in the flange receiving the regulator two staggered holes intended to receive the ends of the connection tubes, a radially enlarged segment being on the side directed towards the regulator. Thanks to the staggering, it is possible to form an assembly for safety between the collar and the connection tube. The connection tubes are

  advantageously fixed in the flange by radial widening, that is

  say that the end of the tube is open and is pressed against the inner wall of the bore with a seal by radial pressure. In a preferred mode, two steps are provided in each hole, so

  that in total three drilling segments are formed in each drilling.

  Thanks to the several drilling segments and steps, the tightness of the assembly can be guaranteed, even under extreme pressure conditions. The central segment of each hole preferably represents approximately half of the total length of the hole considered in the collar. To take into account the difference in the volumes of the refrigerant upstream and downstream of the evaporator, which results from the change in physical state, the connection tubes have different sections, the connection tube serving as a conduit for suction with at least about 1.5 times the cross section of the other connection tube. Furthermore, it is advantageous for the opening serving as an inlet for the refrigerant fluid into the evaporator to have a smaller section than the opening for the outlet of the

hot gas.

  The recesses in the connection elements are advantageously adapted to the shape of the opening and the recesses and openings are preferably superimposed between them. The shape of the openings and recesses can be a function of the given space conditions, and it can be considered advisable that the opening provided for the entry of the coolant consists of an elongated hole having parallel side edges and that the opening scheduled for the

  hot gas outlet has substantially the shape of a rectangle.

  The connection elements must be closed at their outer end and it is considered advantageous to insert in the open front end of the connection element plates covered with solder which are brazed together, so that obtains a tight seal to the refrigerant. To exactly position the connection element on the plate in question, it is advantageous to provide the opening of the plate with a collar which engages in the recess of the connection element. Thanks to this safety plug, the connection element is positioned exactly up to

performing brazing.

  According to another characteristic of the invention, the connection tubes, including the connection elements, each have

a length of at least 150 mm.

  According to another characteristic of the invention, the ends of the connection tubes have a connection profile, for example

  in the form of a molding, for a valve.

  An embodiment of the invention is explained in more detail below with reference to the drawing. In the drawing, FIG. 1 shows a coolant evaporator of a motor vehicle air conditioning installation by a view on the front side which receives the air, FIG. 2 is a view taken in the direction of arrow II of the Figure 1, Figure 3 is a view taken along arrow III of Figure 1, Figure 4 is a section of a connection flange, Figure 5 is a view of an evaporator block taken along arrow V of the Figure 1, without connection tube, Figure 6 is a view of the evaporator block according to arrow VI of Figure 1, Figure 7 shows a connection tube serving as suction pipe, Figure 8 is a view according to arrow VIII of Figure 7, Figure 9 is a view along arrow IX of Figure 7, Figure 10 shows a connection tube serving as a coolant supply, Figure 11 is an enlarged representation of detail IX of Figure 10, Figure 12 is a view of the front side XII of the Figure 10, Figure 13 is a flat view of a sheet of the end plate, Figure 14 is a section along the line XIV-XIV of Figure 13, Figure 15 is an enlarged representation of the detail XV of Figure 14, but in section through the opening,

  Figure 16 shows an alternative embodiment of Figure 15.

  In Figures i to 3, there is shown a complete evaporator 1 for a compression refrigeration installation in different views, namely, in Figure 1, the front side which receives the air, in Figure 2, a view of above and, in Figure 3 a side view. The evaporator 1 is composed of stacked plates 2, each plate 2 being composed of two sheets 4, 5 applied one against the other. These sheets 4, 5 contain cavities between them and in this way form tubular elements which are traversed by the refrigerant. As seen in Figure 1, at one end of the plates 2, the sheets 4, 5 (Figure 2) are provided with stampings 6, 7 at which the plates 2 mutually adjacent come into mutual contact. The plates each disposed at one end of the stack are designated by the reference signs 8 and 9 in Figure 1. They differ from the plates 2 in that they have sheets on the outside of the sheet which are not fitted with stampings end plates of the other plates 2. Between the plates 2 of the plate stack, are arranged ribs 3 which are joined to the plates 2 by brazing and thus serve, on the one hand to improve the transmission of heat and, on the other hand, to give the support plates against each other. The ribs are preferably

  formed by corrugated or full-core ribs.

  Each of the outer plates 8 and 9 is associated with a closure plate 10 which extends parallel to its adjacent plate 8 or 9 and a rib 3 is also arranged between this plate and the plate 8, 9. The closure plates 10 s 'extend over the height of the plate, with the exception of the region of the end of the plates 2 which is provided with stampings. The closure plates 10 have a stiffening rib 11 in their longitudinal extension (Figures 1 and 3). This stiffening rib 11 can

  be formed by a molding made in the closure plate 10.

  As shown in Figures 1 to 3, the evaporator 1 is provided with connection tubes 12 and 13 whose ends which are distant from the stack of plates are threaded in a flange 14. The connection tubes 12 and 13 have elements of shaped connection 15 and 16 which, according to Figure 1, have a flat bearing surface for joining to the end plates 8 and 9 and extend parallel to the direction L of

  the air flow (Figures 2 and 3) below the closure plates 10.

  All the components of evaporator 1, except for the

  flange 14, are brazed to each other in a single working step.

  The flange 14 provided for the connection of a regulator has a flange surface 17 provided with a threaded hole 18 provided in the central region of the flange surface 17 for fixing the regulator. Furthermore, there are provided in the flange 14 two staggered holes 19 and 20 which serve to receive the free ends 12 ′, 13 ′ of the connection tubes 12 and 13. As is clear from Figures 1 to 3, the connection tube 13 serving as a suction pipe has a much larger diameter than the connection tube 12 which conveys the refrigerant, so that account is taken of the difference in physical state of the refrigerant between the inlet side and the

outlet side of the evaporator.

  Figure 4 shows a section of the collar 14 with the ends 12 ', 13' of the connection tubes 12 and 13 housed in this collar. This section of the flange 14 shows that the holes 19 and 20 are staggered holes, each of these holes having two steps 21, 21 'and 22, 22', so that three segments of holes 23, 24 are formed. , 25 for one and 26, 27, 28 for the other. The drilling segments 23, 26 which are distant from the surface 17 of the flange have the smallest diameter, followed by a central drilling segment 24, 27 having a diameter enlarged radially. In position adjacent to the surface 17 of the flange is the drilling segment 25, 28 which has the largest radial dimension. As can be seen in Figure 4, the central segments 24, 27 of the holes have a much larger axial dimension than the other segments of the holes, the central segment 24 of the hole having an axial length which corresponds to approximately half of the total length of the bore 19 or 20. The ends 12 ′, 13 ′ of the tubes are fixed and mounted with a seal in the holes 19, 20 by exclusively mechanical means, which is obtained by radial widening in the segments 24, 25 and 27, 28 respectively of the holes. Under the effect of this development, the wall of the tube is applied with a radial pressure against the internal wall of the holes 19, 20, the rungs 21, 21 'and 22, 22' respectively producing an assembly by safety form s' opposing the axial displacement or the extraction of the ends 12 ′, 13 ′ of the tubes and also contributing to improving the seal. Between the holes 19, 20, there is a hole

  thread 18 intended for fixing the regulator.

  In an alternative embodiment of the attachment of the ends 12 ′, 13 ′ of the tubes in the flange 14, the seal is produced by an O-ring interposed between the end of the tube and the inner wall of the

  holes 19, 20 in the ladder region. In this case, the enlargement-

  Radial is used exclusively for mechanical immobilization.

  Figure 5 shows a view of an evaporator block taken in the direction of arrow V in Figure 1, without connecting tubes. Here, the closure plate 10 extends from the upper edge of the evaporator to the region where the end plate 8 is provided to receive the closure element 15 shown in FIG. 3. In this region, the end plate 8 is provided with an opening 29 for the entry of the coolant, so that the coolant which arrives at the evaporator 1 in the connection tube 12 can be conveyed to the plates 2 (see Figure 1). As Figure 5 shows, the opening 29 for the inlet of the coolant is made in the form of an elongated hole having side edges

parallel 29 ', 29 ".

  Figure 6 shows a view of the evaporator block in the direction of arrow VI in Figure 1, here also without connecting tubes. This representation is similar to that of Figure 5, except that at the lower edge, the closure plate 10 is of a different configuration. On the surface of the end plate 9 which is not covered by the closure plate 10 is fixed the connecting element 16 shown in Figure 1, through which the vaporized refrigerant, which is called hot gas , is sent to the regulator via the connection tube 13 which serves as a suction pipe. An opening 30 which has substantially the shape of a rectangle is used to exit the hot gas from the end plate 9 to

  bring it into the connection piece that is attached to it.

  Figures 7, 8 and 9 show different views of the tube

  connection 13 serving as suction line. Here, the connecting element

  16 is formed in one piece with the connecting tube 13 and deformed to take a substantially rectangular section, so that a flat bearing surface 16 'is obtained for the connection with the end plate 9. As shown in the Figure 9, there is provided, on the flat side 16 'of the connecting element 16, a recess 31 whose shape corresponds to the opening 30 of the end plate 9. If the opening 30 is provided with a collar directed towards the connection element 16, the recess 31

  is dimensioned so that the collar engages in the recess.

  Figure 10 shows the connection tube 12 serving as a coolant supply pipe, and which comprises a connection element 15 formed thereon. This connection element 15 is of substantially rectangular shape, as shown in FIG. 12, so that a flat bearing surface 15 ′ is obtained for assembly with the end plate 8. A surface 15 is provided for recess 32 which corresponds by its shape to the opening 29 produced in the form of an elongated hole, so that this recess 32 comes in coincidence with

  opening 29 during assembly of the evaporator.

  The detail XI of Figure 10 is shown enlarged in Figure 11.

  We can clearly deduce that next to the end of the connection element 15 is fitted in this element a plate 33 which is

  assembled to the inner peripheral surface of the connecting element

  ment 15 by material continuity during brazing of the evaporator, which isolates the internal volume of the connection element 15 from the outside to

  seal refrigerant fluid.

  Figure 13 shows a flat view of a sheet 35 of the plate

  terminal which presents, near the end of its longitudinal dimension

  nale, the opening 29 which is provided with a collar 34. At the other end of the longitudinal dimension, lugs 36 straightened perpendicularly are provided directly at the edge of the sheet, which emerges from Figure 14. Figure 14 also shows the collar 34 which protrudes on the plane of the sheet in the same direction as the lugs 36. FIG. 15 shows an enlarged representation of the section taken through the opening 29 in the form of an elongated hole provided with the collar 34. As a variant, the elongated hole 29 can also be produced without a collar, as shown in the example of FIG. 16, in which the sheet 35 is entirely flat in the region which surrounds the opening 29. In the evaporator according to the invention, the widening of the end 12 ′, 13 ′ of the tube in the flange 14 can be achieved much better with regard to the precision, the deformation of the material and the surface because, under the effect of heating in the oven, the ma first tubes then

  better deformation properties, that is, it is softer.

  This is particularly advantageous for the seats of the O-rings.

Claims (14)

  1. Evaporator for a compression refrigeration installation, in particular for a motor vehicle air conditioning installation, comprising several plates (2) gathered in a stack, which constitute tubular elements and are each composed of two sheets (4, 5) which enclose a cavity therebetween and on which there is provided, near at least one end of the plates (2), a stamping (6, 7) intended to be applied against the adjacent plate (2), and provided with openings for the passage of the coolant, while at the plates (35) of the end plates (8, 9) of the stack, are fixed connection elements (15, 16) having a flat side (15 ', 16' ) directed towards the sheets (35) and a recess (31, 32) provided in this side, and ribs (3) arranged in each gap between two adjacent plates (2, 8, 9), characterized in that the elements of connection (15, 16) consist of segments d formed of a connection tube (12, 13) which extends to a flange (14) of a regulator, the connection tube (12, 13) being formed in one piece, including the element connection   (15, 16), and being assembled to the flange (14) by a mechanical connection.   2. Evaporator according to claim 1, characterized in that in the collar (14) are provided two staggered bores (19, 20) intended to receive the ends (12 ', 13') of the connection tubes (12, 13), a radially enlarged segment (24, 27) on the side facing the regulator. 3. Evaporator according to claim 2, characterized in that the connection tubes (12, 13) are fixed and rigidly immobilized in the   collar (14) by radial widening.   4. Evaporator according to claim 3, characterized in that, in each drilling, two steps are provided (21, 21 ', 22, 22') and that three drilling segments (23, 24, 25 and, respectively, 26, 27 , 28) are formed by these rungs.   5. Evaporator according to claim 4, characterized in that the central segment (24, 27) of each of the holes (19, 20) represents roughly   almost half of the total length of the hole (19, 20) considered.   6. Evaporator according to one of claims 1 to 5, characterized in   that the connection tubes (12, 13) have different sections, the connection tube (13) serving as a suction pipe having at least about 1.5 times the section of the other connection tube (12 ).   7. Evaporator according to one of claims 1 to 6, characterized in   that the opening (29) serving as an inlet for the refrigerant in the evaporator   teur (1) has a smaller section than the opening (30) of the outlet of the hot gas.   8. An evaporator according to claim 7, characterized in that the recesses (31, 32) formed in the connection elements (15, 16) are adapted to the shape of the openings (29, 30), preferably stackable. 9. An evaporator according to claim 7 or 8, characterized in that the opening (29) for the entry of the coolant is made in the form   an elongated hole having parallel side edges (29 ', 29 ").   10. An evaporator according to at least one of claims 7 to 9,   characterized in that the opening (30) for the outlet of the hot gas has   roughly the shape of a rectangle.   11. Evaporator according to one of claims 1 to 10, characterized   in that the connection tubes (12, 13) are closed at the end on the front side of the connection element (15, 16) by means of plates (33) brazed inside.   12. Evaporator according to one of claims 8 to 10, characterized   in that the opening (29) for the inlet of the coolant and / or the opening (30) for the outlet of the hot gas are provided with a collar (34) which   engages in the recess (31) of the connecting element (15, 16).   13. Evaporator according to one of claims 1 to 12, characterized   in that the connection tubes (12, 13), including the connection elements (15, 16), each have a length of at least mm. he 14. An evaporator according to claim 1, characterized in that the ends (12 ', 13') of the connection tubes (12, 13) have a connection profile, for example in the form of a molding, for a valve.