US20180023899A1

US20180023899A1 - Heat exchanger comprising a liquid-refrigerant distribution device

Info

Publication number: US20180023899A1
Application number: US15/547,314
Authority: US
Inventors: Jerome CARETTE; Frederic Crayssac; Marc Wagner
Original assignee: LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Current assignee: LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Priority date: 2015-02-06
Filing date: 2016-02-05
Publication date: 2018-01-25
Also published as: WO2016124748A1; FR3032521B1; CN107208986B; FR3032521A1; EP3254045A1; CN107208986A; EP3254045B1

Abstract

This heat exchanger can include parallel plates which define liquid-refrigerant passages following a longitudinal direction, and—fins extending in each passage in a lateral direction orthogonal to the longitudinal direction, each fin having orifices for the flow of the liquid refrigerant. At least one lower portion of at least one fin defines, with the plate secured to this lower portion, a distribution channel for channeling the liquid refrigerant in the lateral direction. The orifices in said at least one fin are formed by overflow openings in the upper portion. The liquid refrigerant flows through the overflow openings when the or each distribution channel is full of liquid refrigerant.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a § 371 of International PCT Application PCT/EP2016/052524, filed Feb. 5, 2016, which claims the benefit of FR1550960, filed Feb. 6, 2015, both of which are herein incorporated by reference in their entireties.

TECHNICAL FIELD OF THE INVENTION

The present invention concerns a heat exchanger comprising a distribution device configured for distributing a liquid refrigerant in a heat exchanger. The heat exchanger may in particular be a vaporizer used in a column for air separation by cryogenic distillation to ensure vaporization of a liquid in the column vessel, for example liquid oxygen, by the exchange of heat with a calorigenic gas, for example air or nitrogen.
The present invention is used in particular in the field of cryogenic gas separation, in particular of cryogenic air separation (known under the acronym “ASU” for air separation unit), which is used for production of pressurized gaseous oxygen. In particular, the present invention may be applied to a heat exchanger which vaporizes a liquid flow, for example oxygen, nitrogen and/or argon, by exchange of heat with a gas.

BACKGROUND OF THE INVENTION

If the heat exchanger is located in the vessel of a distillation column, it may constitute a vaporizer functioning as a thermosiphon for which the exchanger is immersed in a bath of liquid descending the column, or a vaporizer functioning by film vaporization supplied directly by the liquid falling in the column, and/or by a recirculation pump.
The technology currently used for these phase change exchangers is that of aluminum exchangers with brazed plates and fins, which leads to highly compact devices offering a large exchange area. These exchangers comprise plates between which fins are inserted, thus forming a stack of vaporization passages and condensation passages, the first being intended for vaporizing the liquid refrigerant and the second for condensing a calorigenic gas.
WO-A-2011110782 describes a distribution device comprising parallel plates which define passages for the liquid refrigerant, and several fins which extend in each passage and have orifices for distributing the liquid refrigerant in the lateral direction.
However, in a distribution device of the prior art, the distribution of the liquid refrigerant in the lateral direction is not perfectly uniform. When zones of the exchanger do not receive sufficient liquid refrigerant, solid deposits of impurities may occur due to dry vaporization. Such solid deposits of impurities create a risk of explosion in certain operating conditions of the heat exchanger.
A solution known from document EP-A-0130122 consists of piercing orifices in the parallel plates of the distribution device in order to ensure a rough pre-distribution of the liquid refrigerant along the passages for said liquid. However, the number of orifices arranged along the exchanger is limited in order not to complicate production or weaken the structure, and the effect of standardizing the distribution of the liquid remains insufficient.

SUMMARY OF THE INVENTION

The object of certain embodiments of the present invention is in particular to solve the above-mentioned problems in full or in part by providing a distribution device in which the distribution of the liquid refrigerant is as uniform as possible.
To this end, the object of certain embodiments of the invention is a heat exchanger configured for transferring heat from at least one calorigenic fluid, for example nitrogen, to at least one frigorigenic fluid, for example oxygen, the heat exchanger comprising at least plates arranged parallel to each other so as to define a first series of passages configured for conducting liquid refrigerant globally in a longitudinal direction extending in the vertical direction during operation, each passage being defined between two successive plates, and a second series of passages configured for conducting a calorigenic fluid globally in the longitudinal direction, each passage being defined between two successive plates, the passages of the second series being interposed between two passages of the first series, at least one inlet for liquid refrigerant configured to pour the liquid refrigerant only into the passages of the first series, and distribution means situated in the upper end of the exchanger in passages of the first series only, comprising
fins extending in one or each passage of the first series globally in a lateral direction which is orthogonal to the longitudinal direction and parallel to the plates, each passage of the first series housing several fins succeeding each other in the longitudinal direction, each fin having orifices configured to allow the flow of liquid refrigerant;
at least one fin having an upper portion and a lower portion, the height of the upper portion being greater than the height of the lower portion when the distribution device is in operation and the longitudinal direction extends in the vertical direction,
said at least one lower portion and the plate secured to said at least one lower portion defining at least one distribution channel configured for conducting liquid refrigerant in the lateral direction,
the orifices of said at least one fin being formed by overflow openings situated in said at least one upper portion, the overflow openings being configured such that the liquid refrigerant flows via the overflow openings when said at least one distribution channel is full of liquid refrigerant.
In other words, the or each distribution channel forms a type of trough which extends between the overflow openings and an intersection of the lower portion and the plate secured to this lower portion. The or each distribution channel is globally horizontal when the distribution device is in operation.
Thus the cooperation of the or each distribution channel with the overflow openings of the fin(s) allows distribution of the liquid refrigerant as uniformly as possible in the lateral direction, which limits or prevents the risk of solid deposits of impurities in the heat exchanger.
The plates extend in two dimensions, length and width, respectively in the longitudinal direction and the lateral direction. In each passage, the fins have longilineal forms and extend in the width (lateral direction) of two successive plates.
The longitudinal direction is vertical when the distribution device is in operation. The liquid refrigerant flows globally in the longitudinal direction under gravity. Therefore the liquid refrigerant flows globally vertically in the descending direction.
According to a variant of the invention, the distribution device may comprise a number of plates greater than 20, or even greater than 100. The plates thus form a stack of plates between which passages are defined for the liquid refrigerant, in some cases alternating with conduits for the calorigenic fluid. The distribution device may have a number of liquid refrigerant passages greater than 10, or even greater than 50.
In operation, the liquid refrigerant passes through the distribution device. The distribution device has i) an upstream portion configured for the inlet of the liquid refrigerant, and ii) a downstream portion configured for the outlet of the liquid refrigerant. The fins extend between this upstream portion and the downstream portion.
According to a variant of the invention, each passage has a flat, parallelepipedic form. Since each passage has a flat shape, the distance between two successive plates is small in comparison with the length and width of each successive plate. Preferably, all or some of the fins extend from one plate to the following plate. In other words, these fins are in contact with both plates. This construction allows the fins to be brazed onto both plates, which increases the mechanical strength of the distribution device.
In the present application, the term “in the direction of” means that a direction is substantially parallel or substantially colinear to another direction or plane.
According to one embodiment of the invention, the volume of a respective distribution channel is less than 15%, preferably less than 10%, of the total volume delimited by:

- i) a fin with overflow openings,
- ii) the plate secured to the lower portion of said fin with overflow openings, and
- iii) the fin situated immediately upstream of said fin with overflow openings.

Thus, because of a volume of the distribution channel, the fins with overflow openings cannot cause too great a load loss. A low load loss avoids reducing the flow of liquid refrigerant through the fins with overflow openings, which allows optimum regulation of this flow. The fins with overflow openings therefore fulfil a function of distributing the liquid refrigerant, generating only a low load loss. Each distribution channel is defined by at least one lower portion and by the plate secured to said at least one lower portion.
According to an embodiment of the invention, the overflow openings are distributed over a fin uniformly in the lateral direction.
Thus, uniformly distributed overflow openings allow maximum uniformity of distribution of the liquid refrigerant. Alternatively, certain overflow openings may be distributed non-uniformly in the lateral direction.
According to one embodiment of the invention, an opening ratio having:

- as numerator, the total area of the overflow openings situated in a fin with overflow openings, and
- as denominator, the total area of a face of said fin with overflow openings,

is between 10% and 50%, preferably between 20% and 40%.
Thus, such an opening ratio contributes to minimizing the load loss generated by the fins with overflow openings, while ensuring an adequate flow in the distribution device.
According to one embodiment of the invention, each overflow opening has an area between 1.5 mm²and 10.0 mm², preferably between 2.0 mm²and 5.0 mm².
Thus such an area avoids totally flooding each overflow opening, which contributes to not reducing the flow of liquid refrigerant through each fin.
According to a variant of the invention, some overflow openings have the form of an ellipse, for example circular. Thus such a shape offers an overflow opening width which increases progressively, which limits the height of the liquid refrigerant when the flow of liquid refrigerant increases.
According to a variant of the invention, some overflow openings have the form of triangle pointing towards said at least one lower portion. Thus such a shape offers an overflow opening width which increases progressively, which limits the height of the liquid refrigerant when the flow of liquid refrigerant increases.
According to one embodiment of the invention, an interval measured in the lateral direction between two successive overflow openings is between 1 mm and 6 mm.
Thus, such an interval helps ensure a uniform distribution of liquid refrigerant in the lateral direction while minimizing the load loss created by the fins with overflow openings.
According to a variant of the invention, said interval is constant for the overflow openings of at least one fin.
Thus such an interval contributes to maximizing the uniformity of distribution of the liquid refrigerant in the lateral direction.
In one embodiment of the invention, a minimal distance between i) an overflow opening, and ii) the plate secured to said at least one lower portion, lies between 1 mm and 4 mm, the minimal distance being preferably the same for the majority or totality of overflow openings of a respective fin.
Thus, such a minimal distance allows a distribution channel to have a relatively large volume, which allows limitation of the number of fins with overflow openings in the distribution device.
According to one embodiment of the invention, several fins have respective upper portions with overflow openings.
In other words, there are several stages of distribution of the liquid refrigerant, which helps maximize the uniformity of this distribution.
According to one embodiment of the invention, the overflow openings present in a fin are positioned offset in the lateral direction relative to the overflow openings present in the adjacent fin.
Thus such an offset between overflow openings contributes to increasing the uniformity of the distribution of the liquid refrigerant in the lateral direction.
According to one embodiment of the invention, said offset between the overflow openings present in two adjacent fins represents between 40% and 60% of the length of said interval.
In other words, the overflow openings of two successive fins in the longitudinal direction are arranged substantially offset to each other.
Thus, such a value of the offset between overflow openings helps maximize the uniformity of distribution of the liquid refrigerant in the lateral direction.
According to one embodiment of the invention, at least one fin has a flat shape and extends up to said two successive plates and obliquely to each of said two successive plates so as to form, in cross-section in a plane perpendicular to the plates and to the lateral direction, an acute oblique angle, the oblique angle preferably being between 30° and 60°, further preferably between 40° and 50°.
Thus such a flat, oblique fin takes up relatively little space and is easy to attach to the plates.
According to one embodiment of the invention, each fin has, parallel to the longitudinal direction, a length between 4 mm and 10 mm, and each fin has, parallel to the lateral direction, a width between 4 mm and 10 mm, each fin being able for example to have equal length and width.
Thus, such a length and width allow a large number of fins to be incorporated in the distribution device, which increases the uniformity of distribution of the liquid refrigerant.
According to a variant of the invention, each fin has a fixing portion which is fixed to a plate, for example by brazing.
Thus such a fixing portion allows each fin to be attached to the plates in a simple fashion.
According to a variant of the invention, one and preferably each overflow opening is defined by a through orifice. Alternatively, at least one overflow opening may be defined by a notch extending up to an edge of the corresponding fin.
According to one embodiment of the invention, the distribution device comprises at least one fin having orifices and placed upstream of the fin(s) with overflow openings, the orifices being distributed in the lateral direction, the number of overflow openings per fin being greater than 3 times, preferably than 5 times the number of orifices per fin.
Thus, the fins with orifices may fulfil a function of controlling the flow of liquid refrigerant entering the distribution device by generating a high load loss, while the fins with overflow openings rather fulfil a distribution function while generating only a low load loss. This limits the number of components to be mounted in the distribution device since, because of the fins with orifices, there is no need to provide a perforated bar such as that in WO-A-2011110782 in order to generate a high load loss.
According to a variant of the invention, at least two fins have orifices, the number of orifices per fin increasing in the direction from upstream to downstream.
Thus, these fins with orifices allow optimum control of the flow of liquid refrigerant entering the distribution device.
According to a variant of the invention, the interval between two successive orifices, measured in the lateral direction of the fin with orifices which is situated furthest upstream, lies between 40 mm and 60 mm, and the interval between two successive orifices, measured in the lateral direction of the fin with orifices which is situated furthest downstream, lies between 6 mm and 20 mm.
Therefore, the fin with orifices which is situated furthest upstream has the fewest orifices, while the fin with orifices which is situated furthest downstream has the most orifices, the fins with overflow openings being situated downstream of the fin with orifices which is situated furthest downstream.
Thus, the load loss generated by the fins with orifices diminishes from upstream to downstream, while the uniformity of distribution of the liquid refrigerant increases.
According to a variant of the invention, at least one fin may have, in addition to the overflow openings, at least one purge hole arranged at the bottom of the lower portion. The distribution channel is then formed from several portions separated in twos by a purge hole through which the liquid refrigerant may flow. Such a purge hole allows evacuation of the distribution channel. Advantageously, the area of the or each purge hole is smaller than the area of an overflow opening. Thus the flow through the purge hole has a relatively low flow rate, which avoids disrupting the flow through each overflow opening close to the purge hole.
According to a variant of the invention, the total area of the openings or of the overflow openings for a given fin increases in the longitudinal direction, preferably by increasing the number and/or area of the openings.
In this way, the further the liquid descends in the distribution means, the smaller the spacing between the openings. At the start, if the liquid is poorly distributed, it is forced to circulate laterally up to adjacent openings of the same fin. The greater the distance between two openings, the more effective the redistribution over the width.
Secondly, the object of certain embodiments of the present invention is a distribution method for distributing a liquid refrigerant in a heat exchanger, the distribution method comprising the steps:

- implementing a distribution device according to the invention,
- conducting liquid refrigerant into each passage and globally in a longitudinal direction,
- allowing the flow of liquid refrigerant via the orifices of fins having orifices,
- filling each distribution channel such that liquid refrigerant flows via the overflow openings.

Certain embodiments of the present invention also concerns a heat exchanger configured to transfer heat from at least one from a calorigenic fluid, for example nitrous oxide, to at least one frigorigenic fluid, for example oxygen, the heat exchanger comprising at least one heat exchange unit, at least one liquid refrigerant inlet, the heat exchanger being characterized in that it comprises a distribution device according to any of the preceding claims, the distribution device being arranged to supply liquid refrigerant to the heat exchange unit.
Thus such a heat exchanger limits or avoids the risk of solid deposits of impurities in the heat exchanger, and hence the risk of explosion in certain operating conditions.
The embodiments and variants mentioned above may be taken in isolation or in any technically feasible combination.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be clearly understood and its advantages will arise from the description which follows, given merely as a non-limitative example, and with reference to the attached drawings in which:

FIG. 1 is a diagrammatic cross-section view, in a plane perpendicular to the lateral direction, of a part of a distribution device according to a first embodiment of the invention;

FIG. 2 is a diagrammatic cross-section view, in plane II in FIG. 1 which is parallel to the longitudinal and lateral directions, of the part of the distribution device in FIG. 1,

FIG. 3 is a diagrammatic cross-section view, in a plane perpendicular to the lateral direction, of a part of a heat exchanger comprising the distribution device according to the first embodiment of the invention;

FIG. 4 is a view similar to FIG. 1, illustrating the function of the distribution device of FIG. 3;

FIG. 5 is a view similar to FIG. 2, illustrating the function of the distribution device of FIG. 3;

FIGS. 6 and 7 are views similar to FIGS. 1 and 2 respectively, illustrating a part of a distribution device according to a second embodiment of the invention;

FIGS. 8 and 9 are views similar to FIGS. 1 and 2 respectively, illustrating a part of a distribution device according to a third embodiment of the invention;

FIG. 10 is a view similar to FIG. 1, illustrating a part of a distribution device according to a fourth embodiment of the invention;

FIG. 11 is a view similar to FIG. 10, illustrating a part of a distribution device according to a fifth embodiment of the invention;

FIG. 12 is a view similar to FIG. 10, illustrating a part of a distribution device according to a sixth embodiment of the invention;

FIG. 13 is a view similar to FIG. 1, illustrating a part of a distribution device according to a seventh embodiment of the invention;

FIG. 14 is a view similar to FIG. 1, illustrating a part of a distribution device according to an eighth embodiment of the invention; and

FIG. 15 illustrates a distribution method according to the invention.

DETAILED DESCRIPTION

FIGS. 1, 2 and 3 illustrate a distribution device 1 which is configured for distributing a liquid refrigerant F1, in this case liquid oxygen, into a heat exchanger 2. The heat exchanger 2 is configured for transferring heat from a calorigenic fluid F2, here gaseous nitrogen, to the frigorigenic fluid, here oxygen. Before the transfer of heat, the liquid refrigerant F1 (FIG. 3) is in a holding tank 3 belonging to the heat exchanger 2.
The distribution device 1 comprises plates 11, 12, 13, 14 and equivalent which are arranged parallel to each other. The distribution device 1 comprises a number of stacked plates equal to approximately 200. Each of the plates 11, 12, 13, 14 extends in two dimensions, respectively length and width, which are defined in a longitudinal direction X and a lateral direction Y respectively.
The lateral direction Y is orthogonal to the longitudinal direction X and parallel to the plates 11, 12, 13, 14. The longitudinal direction X is vertical when the distribution device 1 is in operation. The liquid refrigerant F1 globally flows in the longitudinal direction X under gravity. Therefore the liquid refrigerant F1 globally flows vertically in the descending direction.
The plates 11, 12, 13, 14 are arranged so as to define passages 20, 30 and equivalent which are configured for conducting the liquid refrigerant F1 globally in the longitudinal direction X. Each passage 20 or 30 is defined between two successive plates 11, 12, 13, 14. Each passage 20, 30 has a flat parallelepipedic form. The distance between two successive plates 11 and 12 is small in comparison with the length (in direction X) and width (in direction Y) of each successive plate 11 or 12. In the heat exchanger 2, passages 20, 30 for liquid refrigerant F1 alternate with passages of flat parallelepipedic form (not shown) for the calorigenic fluid.
The distribution device 1 also comprises fins 21, 22, 23, 24 and 31, 32, 33, 34, which extend respectively in each passage 20 and 30, globally in the lateral direction Y. The fins 21, 22, 23, 24 extend in the passage 20, while the fins 31, 32, 33, 34 extend in the passage 30. In each passage 20 or 30, the fins 21, 22, 23, 24, 31, 32, 33 and 34 have longilineal forms and extend in the lateral direction Y of two successive plates 11 and 12 or 13 and 14.
Each fin 21, 22, 23, 24, 31, 32, 33 or 34 has a flat shape and extends up to two successive plates 11 and 12 or 13 and 14. Each fin 21 or equivalent extends obliquely to each of the two successive plates 11 and 12 or 13 and 14 so as to form, in cross-section in a plane perpendicular to the plates and to the lateral direction Y (here the plane of FIG. 1), an oblique angle A21 which is acute. The oblique angle A21 is here 45°.
Each fin 21 or equivalent has, parallel to the longitudinal direction X, a length X21 which is here equal to 5 mm. Each fin 21 or equivalent has, parallel to the lateral direction Y, a width Y21 which is here equal to 5 mm and hence equal to the length X21. Each fin 21 or equivalent here has a fixing portion 21.5 which is flat and which is fixed by brazing to a respective plate 11 or equivalent. All fins 21, 22, 23, 24 extend from one plate 11 up to the next plate 12. In other words, these fins 21, 22, 23, 24 are in contact with both plates 11 and 12. The fins 21, 22, 23, 24 are brazed onto the two plates 11 and 12.
Each passage 20 or 30 here houses four fins, respectively 21, 22, 23, 24 and 31, 32, 33, 34, which succeed each other in the longitudinal direction X. Each fin 21 or equivalent has orifices 40 which are configured to allow the flow of the liquid refrigerant F1 through the respective fin 21 or equivalent.
In the example of FIGS. 1 to 5, each fin 21, 22, 23, 24, 31, 32, 33 or 34 has an upper portion 21.1 and equivalent, and a lower portion 21.2 and equivalent. When the distribution device is in operation (FIGS. 4 and 5), the height of the upper portion 21.1 is greater than the height of the lower portion 21.2.
Each lower portion 21.2 or equivalent, and the respective plate 11 or equivalent secured to the lower portion 21.2, define a distribution channel 42 which is configured for conducting liquid refrigerant F1 in the lateral direction Y.
In the example of FIGS. 1 to 5, the orifices 40 of each fin 21 or equivalent are formed by overflow openings 40 which are situated in each respective upper portion 21.1 or equivalent. All fins 21 and equivalent have respective upper portions 21.1 and equivalent which have overflow openings 40. For evident reasons of clarity, not all overflow openings 40 are marked on FIGS. 1 to 5.
The overflow openings 40 of each fin 21 or equivalent are configured such that the liquid refrigerant F1 flows via the overflow openings 40 when the distribution channel 42 is full of liquid refrigerant F1.
All overflow openings 40 here have the shape of triangles pointing towards each respective lower portion 21.2. The overflow openings 40 are here distributed over a respective fin 21 or equivalent uniformly in the lateral direction Y.
An interval D40, measured in the lateral direction between two successive overflow openings 40, is here constant and equal to 4 mm for overflow openings 40 of each fin 21 or equivalent.
Also, a minimal distance H40 between i) an overflow opening 40, and ii) the plate 11 secured to the respective lower portion 21.2, is equal to 3 mm. This minimal distance H40 is the same (constant) for all overflow openings 40 of a respective fin 21 or equivalent.
In the example of FIGS. 1 to 5, the overflow openings 40 present in a fin 21 are positioned offset in the lateral direction Y relative to the overflow openings 40 present in the adjacent fin 22. The offset D40/2 between the overflow openings 40 present in two adjacent fins 21 and 22 here represents 50% of the length of interval D40.
Each overflow opening 40 here has an area equal to 4 mm². An opening ratio having:

- for the numerator, the total area of the overflow openings 40 situated in a fin 21 or equivalent with overflow openings 40, and
- for the denominator, the total area of a face 21.0 of this fin 21,

is here equal to 20%.
FIGS. 4 and 5 illustrate more particularly the function of the distribution device 1. The liquid refrigerant F1 is shown shaded. As FIGS. 4 and 5 show, the liquid refrigerant F1 overflows through each overflow opening 40 and fills each distribution channel 42 of the fins 21, 22, 23, 24, 31, 32, 33 and 34.
As FIGS. 4 and 5 show, the volume of each distribution channel 42 (shown shaded on FIG. 4 or 5) is less than 10% of the total volume (shown checked on FIG. 4) delimited by:
i) a respective fin 222 with overflow openings 240,
ii) the plate 11 secured to the lower portion of this fin 222, and
iii) the fin 221 situated immediately upstream of the fin 222.
FIG. 15 illustrates a distribution method according to the invention for distributing the liquid refrigerant F1 in the heat exchanger 2. This distribution method comprises in particular the steps:
1001) implementing the distribution device 1,
1002) conducting the liquid refrigerant F1 into the passages 20 and 30 and globally in a longitudinal direction X,
1003) allowing the flow of the liquid refrigerant F1 through the orifices of the fins 21 and equivalent with openings 40,
1004) filling each distribution channel 42 such that the liquid refrigerant F1 flows through the overflow openings 40; this step 1004) results in the operating state illustrated in FIGS. 4 and 5.
Each distribution channel 42 is globally horizontal when the distribution device 1 is in operation. The cooperation of each distribution channel 42 with the overflow openings 40 allows the liquid refrigerant F1 to be distributed as uniformly as possible in the lateral direction Y.
As FIG. 3 shows, the heat exchanger 2 comprises a heat exchange unit, partially shown, with reference 4 in FIG. 3. Furthermore, the heat exchanger 2 comprises an inlet for calorigenic fluid F2 and an inlet 8 for liquid refrigerant F1. The inlet 8 is here formed by perforations in a perforated bar 9.
The heat exchanger 2 also comprises the distribution device 1 which is configured to supply liquid refrigerant F1 to the heat exchange unit 4. In this case, the heat exchanger 2 includes a holding tank 3 in which the liquid refrigerant F1 is stored before flowing towards the distribution device 1. In operation, the liquid refrigerant F1 passes through the distribution device 1.
Second and third embodiments of the invention share the feature that the total area of all overflow openings 140, 240, 241 for a given fin 121, 122, 123, 124 increases from top to bottom. This may be achieved by increasing the number and/or area of the openings.
FIGS. 6 and 7 illustrate a part of a distribution device 101 according to the second embodiment of the invention. Insofar as the distribution device 101 is similar to the distribution device 1, the description of the distribution device 1 given above in relation to FIGS. 1 to 5 may be transposed to the distribution device 101 with the exception of the significant differences explained below.
A component of the distribution device 101 which is identical or corresponds in structure or function to a component of the distribution device 1 carries the same numerical reference increased by 100. Thus we have plates 111, 112, fins 121, 122, 123, 124, overflow openings 140 and distribution channels 142.
The distribution device 101 differs from the distribution device 1 in that the overflow openings 140 have an elliptical shape. However, as in the distribution device 101, each orifice of each fin 121, 122, 123, 124 forms an overflow opening 140.
The fins 121, 123 have the same number of overflow openings, but the areas of the openings 140 of the lower fin 123 are smaller than those of the openings 140 of the higher fin 123. The openings 140 of the fin 121 are fewer, but they have the same shape as those of the lower fin 122. This is also the case for the openings of fins 123 and 124. The total area of the openings increases in the direction from upstream to downstream (descending direction on FIG. 7), i.e. downward during operation of the exchanger.
FIGS. 8 and 9 illustrate a part of a distribution device 201 according to a third embodiment of the invention. Insofar as the distribution device 201 is similar to the distribution device 101, the description of the distribution device 101 given above in relation to FIGS. 6 and 7 may be transposed to the distribution device 201 with the exception of the significant differences explained below.
A component of the distribution device 201 which is identical or corresponds in structure or function to a component of the distribution device 101 carries the same numerical reference increased by 100. Thus we have plates 211, 212, fins 221, 222, 223, 224, overflow openings 240 and distribution channels 242.
The distribution device 201 differs from the distribution device 101 since two fins 221 and 222 have orifices 241 which do not form overflow openings 240. Only the fins 223 and 224 have overflow openings 240. In fact, the orifices 241 are few in number on fins 221 and 222 such that the orifices 241 are flooded when the distribution device 201 is in operation.
The fins 221 and 222 are placed upstream of the fins 223 and 224 with overflow openings 240. The orifices 241 are distributed in the lateral direction. The number of overflow openings 240 per fin 223 or 224 is greater than 5 times the number of orifices 241 per fin 221 or 222.
The number of orifices 241 per fin 221 or 222 increases in the direction from upstream to downstream (descending direction on FIG. 9), i.e. downward during operation of the exchanger. The interval D241.1 between two successive orifices 241, measured in the lateral direction of the fin 221 with orifices 241 which is situated furthest upstream (at the top on FIG. 9), is here equal to 51 mm. In fact, the spacing 11-12 between plates 11 and 12 is approximately equal to 51 mm. The interval D241.2 between two successive orifices 241, measured in the lateral direction of the fin 222 with orifices 241 which is situated furthest downstream, is here equal to 20 mm.
In contrast to the distribution device 1, when the distribution device 201 is in operation, fins 221 and 222 with orifices 241 may fulfil a function of controlling the flow rate of the liquid refrigerant entering the distribution device 201 while generating a high load loss, whereas fins 223 and 224 with overflow openings 240 rather fulfil a distribution function while generating only a low load loss.
FIG. 10 illustrates a part of a distribution device 301 according to a fourth embodiment of the invention. Insofar as the distribution device 301 is similar to the distribution device 1, the description of the distribution device 1 given above in relation to FIGS. 1 to 5 may be transposed to the distribution device 301 with the exception of the significant differences explained below.
A component of the distribution device 301 which is identical or corresponds in structure or function to a component of the distribution device 1 carries the same numerical reference increased by 300. Thus we have plates 311, 312, a passage 320, and fins 321, 322, 323, 324.
The distribution device 301 differs from the distribution device 1 since the fins 321, 322, 323, 324 and the plates 311 and 312 are arranged in a zone of the distribution device 301 in which the passage 320 is relatively wide, because this zone has no conduits for calorigenic fluid F2. In fact, each conduit for calorigenic fluid F2 is blocked by a stopper 350, and the outlet (not shown) of the conduits for calorigenic fluid F2 is located on a lateral face of the distribution device 301.
Therefore at the level of the fins 321, 322, 323, 324, the passages 320 may be arranged over the entire height, measured in the direction Z, of the distribution device 301, whereas the passages 20 and 30 alternate with respective conduits for calorigenic fluid F2. For example, the spacing 311-312 between the plates 311 and 312 is approximately equal to 110 mm, whereas the spacing 11-12 between the plates 11 and 12 is approximately equal to 51 mm.
Thus the fixing portion of each fin 321, 322, 323, 324 is relatively small, which reduces the stresses on the brazing fillets formed between the plate and the fin.
Also, the fins 321, 322, 323, 324 may have orifices and overflow openings configured as in the first embodiment (FIGS. 1 to 5: constant number of overflow openings) or as in the third embodiment (FIGS. 8 and 9: progressive increase in the number of orifices).
FIG. 11 illustrates a part of a distribution device 401 according to a fifth embodiment of the invention. The distribution device 401 combines:

- fins 421 and 422 arranged in a zone in which the spacing between plates 411 and 412 is large (e.g.: 110 mm),
- with fins 423, 424 and equivalent arranged a zone in which the passage 420 is constricted (e.g.: 55 mm) because of the alternate presence of conduits for calorigenic fluid F2.

Each conduit for calorigenic fluid F2 is blocked by a stopper 450, and the outlet (not shown) of the conduits for calorigenic fluid F2 is situated on a lateral face of the distribution device 401.
The fins 421, 422 arranged in the wide zone of passage 420 may have orifices but not overflow openings, whereas the fins 423, 424 arranged in the narrow zone of passage 420 may have overflow openings.
FIG. 11 illustrates a part of the distribution device 501 according to a sixth embodiment of the invention. The distribution device 501 is similar to the distribution device 1. The distribution device 501 comprises plates 511, 512 and equivalent, an inlet 508 for liquid refrigerant, fins 521 and equivalent, and a stopper 550 for blocking the conduits for calorigenic fluid F2.
The distribution device 501 differs from the distribution device 1 since the zone in which the holding tank 503 is arranged is wider than the zone in which the holding tank 3 is arranged, which allows an increase in the distance between the plates 511 and 512 and each orifice forming the inlet 508 for liquid refrigerant. Thus the risk of partial or total blockage of each of these orifices due to capillary action from brazing is reduced or avoided. Furthermore, this wider zone allows larger orifices to be defined for the flow of liquid refrigerant.
Naturally, the invention is not limited to the particular examples described and illustrated in the present application. Other variants or embodiments within the reach of the person skilled in the art may also be considered without leaving the scope of the invention as defined by the attached claims.
Thus, as an alternative to the embodiments described above, the fins may have profiles other than flat and oblique. For example, FIG. 13 illustrates a part of a distribution device 601 in which the fins are flat and composed of an oblique strip and a lateral strip which is horizontal when the distribution device is in operation. Similarly, FIG. 13 illustrates a part of a distribution device 601 in which the fins are flat and sinusoidal.
While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims. The present invention may suitably comprise, consist or consist essentially of the elements disclosed and may be practiced in the absence of an element not disclosed. Furthermore, if there is language referring to order, such as first and second, it should be understood in an exemplary sense and not in a limiting sense. For example, it can be recognized by those skilled in the art that certain steps can be combined into a single step.
The singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise.
“Comprising” in a claim is an open transitional term which means the subsequently identified claim elements are a nonexclusive listing (i.e., anything else may be additionally included and remain within the scope of “comprising”). “Comprising” as used herein may be replaced by the more limited transitional terms “consisting essentially of” and “consisting of” unless otherwise indicated herein.
“Providing” in a claim is defined to mean furnishing, supplying, making available, or preparing something. The step may be performed by any actor in the absence of express language in the claim to the contrary.
Optional or optionally means that the subsequently described event or circumstances may or may not occur. The description includes instances where the event or circumstance occurs and instances where it does not occur.
Ranges may be expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, it is to be understood that another embodiment is from the one particular value and/or to the other particular value, along with all combinations within said range.
All references identified herein are each hereby incorporated by reference into this application in their entireties, as well as for the specific information for which each is cited.

Claims

1-14. (canceled)

15. A heat exchanger configured for transferring heat from at least one calorigenic fluid to at least one frigorigenic fluid, the heat exchanger comprising:

plates arranged parallel to each other so as to define a first series of passages configured for conducting liquid refrigerant globally in a longitudinal direction extending in the vertical direction during operation, each passage being defined between two successive plates, and a second series of passages configured for conducting a calorigenic fluid globally in the longitudinal direction, each passage being defined between two successive plates, the passages of the second series being interposed between two passages of the first series;

at least one inlet for liquid refrigerant configured to pour the liquid refrigerant only into the passages of the first series; and

distribution means situated in the upper end of the exchanger in passages of the first series only, comprising fins extending in one or each passage of the first series globally in a lateral direction which is orthogonal to the longitudinal direction and parallel to the plates, each passage of the first series housing several fins succeeding each other in the longitudinal direction,

wherein each fin comprises orifices configured to allow the flow of the liquid refrigerant;

wherein at least one fin having an upper portion and a lower portion, the height of the upper portion being greater than the height of the lower portion when the distribution device is in operation and the longitudinal direction extends in the vertical direction,

wherein said at least one lower portion and the plate secured to said at least one lower portion defining at least one distribution channel configured for conducting liquid refrigerant in the lateral direction,

wherein the orifices of said at least one fin being formed by overflow openings situated in said at least one upper portion, the overflow openings being configured such that the liquid refrigerant flows via the overflow openings when said at least one distribution channel is full of liquid refrigerant.

16. The heat exchanger as claimed in claim 15, wherein the volume of a respective distribution channel is less than 15% of the total volume delimited by:

i) a fin with overflow openings,

ii) the plate secured to the lower portion of said fin with overflow openings, and

iii) the fin situated immediately upstream of said fin with overflow openings.

17. The heat exchanger as claimed in claim 15, wherein the overflow openings are distributed over a fin uniformly in the lateral direction.

18. The heat exchanger as claimed in claim 15, wherein an opening ratio having:

as numerator, the total area of the overflow openings situated in a fin with overflow openings, and

as denominator, the total area of a face of said fin with overflow openings,

is between 10% and 50%.

19. The heat exchanger as claimed in claim 15, wherein each overflow opening has an area between 1.5 mm²and 10.0 mm².

20. The heat exchanger as claimed in claim 15, wherein an interval measured in the lateral direction between two successive overflow openings is between 1 mm and 6 mm.

21. The heat exchanger as claimed in claim 15, wherein a minimal distance between i) an overflow opening, and ii) the plate secured to said at least one lower portion, lies between 1 mm and 4 mm.

22. The heat exchanger as claimed in claim 21, wherein the minimal distance is the same for the majority or totality of overflow openings of a respective fin.

23. The heat exchanger as claimed in claim 15, wherein several fins have respective upper portions with overflow openings.

24. The heat exchanger as claimed in claim 23, wherein the overflow openings present in a fin are positioned offset in the lateral direction relative to the overflow openings present in the adjacent fin.

25. The heat exchanger as claimed in claim 24, wherein said offset between the overflow openings present in two adjacent fins represents between 40% and 60% of the length of said interval.

26. The heat exchanger as claimed in claim 15, wherein at least one fin has a flat shape and extends up to said two successive plates and obliquely to each of said two successive plates so as to form, in cross-section in a plane perpendicular to the plates and to the lateral direction, an acute oblique angle.

27. The heat exchanger as claimed in claim 15, wherein the oblique angle is between 30° and 60°.

28. The heat exchanger as claimed in claim 15, wherein each fin has, parallel to the longitudinal direction, a length between 4 mm and 10 mm, and wherein each fin has, parallel to the lateral direction, a width between 4 mm and 10 mm, each fin being able for example to have equal length and width.

29. The heat exchanger as claimed in claim 15, comprising at least one fin having orifices and placed upstream of the fin(s) with overflow openings, the orifices being distributed in the lateral direction, the number of overflow openings per fin being greater than 3 times the number of orifices per fin.

30. The heat exchanger as claimed in claim 15, wherein the total area of the openings or of the overflow openings for a given fin increases in the longitudinal direction by increasing the number and/or area of the openings.