ES3035992T3 - Recuperator, parts of which are manufactured by injection moulding - Google Patents

Abstract

The invention relates to a recuperator comprising plates stacked one on top of another and extending parallel to their main direction. At least some plates are provided, over at least a substantial part of their surface, with profiles with side walls parallel to each other and with a component transverse to the main direction of the plates. Between the side walls, there are channels parallel to each other. Each side wall is adjacent on one side to channels of the first type and on the other to channels of the second type. Adjacent plates, stacked on top of each other, are connected by their edges parallel to the channels. The profiled plates are manufactured by injection molding. The profiled plates preferably comprise side wall pieces parallel to the longitudinal direction of the profiles and forming a connection with the side wall pieces of the adjacent plates. (Automatic translation with Google Translate, no legal value)

Description

DESCRIPTION

Recuperator, whose parts are manufactured by injection molding

The invention relates to recuperators, that is, heat exchangers which are configured to transfer thermal energy between two fluids which are guided through two series of channels thermally coupled to each other, where the two media remain separated.

The invention relates more particularly to a recuperator comprising a number of plates stacked one on top of the other and extending mutually parallel, wherein at least part of the number of plates is provided on at least a part of its surface with profiles which form channels extending between the plates and wherein the channels present on each side of a plate extend parallel, wherein each of the plates is adjacent on one of its sides to channels of the first type and is adjacent on its other side to channels of the second type, and wherein the adjacent plates stacked one on top of the other are mutually connected at their edges extending parallel to the channels.

Such recuperators are known, for example, from EP-A-0666973. This document describes a recuperator comprising a number of plates stacked on top of each other and extending with their main direction parallel to each other, wherein at least part of the number of plates is provided over at least a substantial part of its surface with profiles comprising side walls which extend mutually parallel and with a component transversely to the main direction of the plates, and mutually parallel extending channels are present between the side walls, wherein each of the side walls is adjacent on one of its sides to channels of the first type and is adjacent on its other side to channels of the second type, and wherein the adjacent plates stacked on top of each other are mutually connected at their edges extending parallel to the channels.

These prior art recuperators use plates provided with profiles and manufactured by thermoforming. Although thermoforming produces a satisfactory product, it has limitations with respect to the material and shape of the channels. Further research has shown that there is a need for greater freedom in the choice of channel shapes and materials, for example, with respect to resistance to aggressive substances and temperatures. Thermoforming also requires a relatively large number of operations, such as extrusion of the sheet, handling of the sheet rolls, removal of the formed plates from the thermoforming machine, stacking of the plates, and forming a connection between the plates using adhesive, chemically by immersion in a mild solvent, or ultrasonic welding. These prior art recuperators also comprise a series of walls which are held against the sides of the stack of plates by means of hot melt, since the sides of the plate must be sealed from the surrounding area.

EP2950026 describes a counterflow air-to-air energy exchange assembly which may include a plurality of air channel tiers configured to allow air to pass therethrough. Each of the air channels may include a spacer layer having a plurality of modular spacer components secured together. At least two of the modular spacer components are identical in size and shape. The spacer layer includes a plurality of air channels. Each of the plurality of air channels extends from an air inlet to an air outlet.

The object of the invention is to provide a recuperator which makes the aforementioned drawbacks evident.

This object is achieved with a recuperator of the type mentioned above, in which the plates which are provided with profiles are manufactured by injection molding.

Many more materials are suitable for injection molding than for thermoforming, which increases the material selection. The injection molding process provides greater freedom with regard to channel shapes and allows for greater precision.

It should be noted that EP-A-2614 764 describes a heat exchanger assembled from stacked plates, each manufactured by injection molding. However, the same type of channels are present on both sides of the side walls, as channels of different types are always separated by the plates themselves. No heat transport occurs here through the side walls.

According to a first preferred embodiment, the side walls of the profiles extend substantially transversely to the main plane. This keeps the height of these walls as small as possible, which facilitates injection molding.

Furthermore, it has been found attractive that the average distance between adjacent side walls is smaller than the width of the side walls.

It has also been found attractive that the thickness of the sidewalls is at least a factor of two smaller than the average distance between the sidewalls.

The recuperators can be manufactured in different geometries. Some geometries use only profiled plates, but others alternate profiled plates with flat plates. Profiled plates manufactured by injection molding can be combined with other profiled plates formed by thermoforming, or with flat plates, which may or may not be formed by injection molding.

The invention further relates to a method for manufacturing a recuperator, which recuperator is provided with a number of mutually parallel extending plates, at least some of which are provided on at least a part of their surface with profiles, wherein the profiles are provided with side walls which extend with a component transversely to the main direction of the plates and wherein mutually parallel extending channels are present between the side walls, wherein each of the side walls is adjacent on one of its sides to channels of the first type and is adjacent on its other side to channels of the second type, wherein adjacent plates stacked with each other are mutually connected at their edges extending parallel to the channels, and wherein at least some of the plates are manufactured by injection molding and the plates and plates thus manufactured which may have been manufactured in another way are stacked.

In order to maximize the transfer of thermal energy between the fluids, it is preferred that the plates be as thin as possible, also in recuperator parts manufactured by injection molding. This also reduces material usage. According to a preferred embodiment, the plates, which are provided with a profile, have a thickness of less than 500 µm. For the same reason, it is more preferable to apply even smaller thicknesses, such as less than 400 µm, less than 250 µm, less than 150 µm, or less than 100 µm. These smaller thicknesses are possible thanks to modern injection molding techniques, such as injection from the center of the plate, the use of a series of hot runners, the application of higher pressure such as >150 MPa (>1500 bar) or >200 MPa (>2000 bar), and/or the use of materials with a melt flow index >120.

According to a further preferred embodiment, the plates, which are provided with a profile, are manufactured from polypropylene. Polypropylene is a material that can be supplied with a melt flow index greater than 120, and is also a material that can easily withstand the aggressiveness of various fluids.

During thermal energy transfer, it is attractive if not only sensible heat is transferred, but also latent heat. This requires condensation and evaporation to alternate over time in a single channel, and condensation and evaporation to occur simultaneously in different channels. To improve evaporation, it is preferable for the surface of profiled plates to have a capillary or hydrophilic structure. This is because water spreads due to the hydrophilic structure, allowing it to evaporate more effectively.

Since geometry in which only profiled plates are applied reduces material usage by half, it is preferred that all plates be provided with a profile.

In injection molding, it is attractive to place the injection points in the center of the plate. To minimize obstruction of the flow of liquid plastic in the vicinity of the injection points, it is preferable to provide profiled plates manufactured by injection molding with at least one distribution strip extending transversely to the longitudinal direction of the profiles, parallel to the main direction of the plate. In combination with the placement of one or more injection points on these strips, improved plastic distribution is achieved, which can significantly reduce cycle times.

According to a further preferred embodiment, the profiled plates are provided with an elongated distribution strip extending transversely to the longitudinal direction of the plate, substantially in the center of the profiles and parallel to the main plane of the plate. The injection point(s) are positioned on this distribution strip.

This same advantage is achieved when, during injection molding, the plates are injected into a plate distribution strip which is located between the profiles and extends transversely to the profiles.

The recuperator must be provided with side walls that extend parallel to the channels and transversely to the main plane of the plates, since the outermost channels must be closed off from the surrounding area. Therefore, it is attractive for profiled plates to comprise side wall pieces that extend parallel to the longitudinal direction of the profiles and form a connection with the side wall pieces of adjacent plates. The side wall pieces of the plates, which are provided with profiles and which are stacked on top of each other, form the side walls of the recuperator. These features are difficult to implement in plates manufactured by thermoforming, but can be easily implemented in plates manufactured by injection molding. These side wall pieces are preferably arranged on both mutually opposite sides of the plates, so that a side wall is created on both sides of the recuperator. Furthermore, it is possible for the side wall pieces on each side to extend only on one side. In this case, the width of the side wall pieces corresponds to the distance between the plates. However, it is also possible for the sidewall pieces to extend on both sides. The width of the sidewall pieces here is equivalent to a fraction of the total width, but the sum of the widths of both sidewall pieces on one side is equal to the distance between the panels.

The sidewall pieces preferably form a form-locking connection with the sidewall pieces of the adjacent plates. Furthermore, the situation also applies where, in the absence of sidewall pieces on an adjacent plate, the sidewall pieces are connected directly to the adjacent plate itself by means of a form-locking connection. A form-locking connection is understood to mean not only a snap-on connection, but also other types of connections, such as a connection in which a tongue moves into a groove and in which the tongue and groove have side walls that extend conically at an angle between 0° and 7° with respect to the direction of movement. The material deforms here during insertion, resulting in a wedging action. A form-locking connection facilitates the mutual connection of the plates after stacking without the application of adhesive or other foreign materials, which could cause problems during reuse.

This embodiment also relates to a method in which the side edges of the plates are provided with side wall pieces and the side edges of the plates are mutually connected by forming a form-lock connection.

Heat exchangers must be provided with connecting pieces to transport fluids to and from the channels. The plates preferably extend into connecting pieces that connect to the heat exchanger. These connecting pieces are also known as headers in heat exchanger jargon.

Furthermore, it is attractive that the plates extend into connecting pieces that connect to the recuperator, and that the sidewall pieces extend further along at least part of the edge of the connecting pieces. This also forms the sidewalls of the connecting pieces at the same time as it forms the sidewalls of the actual recuperator.

As noted above, the plates of real recuperators extend toward the connecting pieces. In real recuperators, the plates are kept at a distance from each other by the profile. No profiles are present at the position of the connecting pieces. In order to maintain the mutual distance between the plates also at the position of the connecting pieces, it is preferred that the plates be provided with support profiles located at the position of the connecting pieces, which profiles can also function in another way as a guide for the fluids.

Instead of the side walls, which are assembled in each case from side wall pieces associated with the plates, it is also possible for the recuperator to be provided with side wall plates that extend transversely to the main plane of the plates and on each side of the plates.

As already explained, a recuperator can be assembled from alternately stacked flat and profiled plates or from profiled plates only. In most cases, these plates will be the same profiled plates in each case, although it is also possible for the recuperator to be assembled from alternately stacked plates of the first and second types, in which the plates of the first and second types differ from each other.

This embodiment further provides a method in which plates of a first type and plates of a second type are stacked alternately during stacking.

The aforementioned measure requires the production of different types of plates. If the design allows, it may be attractive to have the second type of plates correspond to the first type of plates rotated 180° around an axis parallel to the longitudinal direction of the channels.

This measure also provides such a method, where the plates of the second type correspond to the mirror image of the plates of the first type and where only the plates of the first type are stacked during stacking, where every second plate is rotated before stacking.

In many geometries, channels extend between adjacent plates such that the "height" of the channels is limited to the distance between the two plates. Research has shown that a larger channel height can be attractive in terms of flow resistance. A further embodiment provides for this purpose the measurement of channels present in adjacent plates forming a combined channel. A maximum height of a combined channel can be obtained here, which corresponds to twice the distance between the two plates.

The aforementioned research has further demonstrated that the relationship between flow resistance and heat transfer becomes more attractive when the tall channel narrows to approximately half its height. Therefore, a specific embodiment provides the measurement that the cross-section of combined channels formed by mutually connecting channels is substantially diabolo-shaped.

Channels with a height equal to the width or channels with a height considerably greater than the width are assumed in all of the above. The height here is the cross-sectional measurement of the channel transverse to the main plane of the plates. The production of plates provided with a profile to form such channels frequently causes problems during thermoforming, as these shapes are difficult to release from the corresponding molds. To avoid this, an alternative embodiment proposes that the width of the side walls be less than the distance between adjacent side walls, that the channels have an elongated cross-section, and that the main plane of the plates extend substantially in the longitudinal direction of the cross-section of the channels. The largest dimension of the channel cross-section extends substantially parallel to the main plane of the plate. This further simplifies the release of the formed plate from the mold. This is the case for plates produced both by injection molding and thermoforming, and for recuperators assembled from such plates. In this configuration, heat transfer inevitably takes place through the plates, this being simply an option in the configuration initially described.

The feature elucidated above requires walls that extend transversely to the main plane of the plates and form the end walls of the channels. According to one embodiment, for this purpose, the plates are provided with projections extending substantially transversely to the main plane of the plates, on both sides of the plates and parallel to the longitudinal direction of the channels, these projections forming the end walls of the channels.

To complete the end walls, it is preferable for the protrusions of adjacent plates to be connected to each other. This is necessary so that the protrusions on the outer side of the plates achieve a good seal with respect to the surrounding area, but this is not necessary per se for the protrusions located on the inside, although it does make the structure more rigid so it can better withstand high fluid pressures.

The projections of adjacent plates are preferably connected to each other by means of a form-lock connection. This form-lock connection simplifies assembly, as neither adhesive nor welding is required. The previous clarification in this description also applies to this form-lock connection.

Research has shown that the diabolo shape is particularly attractive with respect to the relationship between flow resistance and heat transfer. According to one embodiment, the cross-section of the channels is therefore substantially diabolo-shaped. Diabolo shape is understood to mean an elongated, substantially rectangular shape with a distance between the long sides that is smaller at the center than the distance between the long sides at the ends. The shape may also be provided with rounded corners and the like.

The application of the aforementioned structure, with a main plane of the plates extending substantially in the longitudinal direction of the cross-section of the channels, entails the problem that the connecting pieces cannot be provided with extensions of the plates of the actual recuperator. A specific embodiment provides for this purpose by the recuperator being coupled to connecting pieces which are provided with plates extending transversely to the main plane of the recuperator plates.

In order to obtain a good connection between the channels in the actual recuperator and the corresponding spaces of the connecting piece, it is preferred that the connecting pieces are formed in individual units which are connected with their open side to an open side of the recuperator, and that the walls of the channels extending transversely to the main plane of the channels are connected to the positions of the plates of the connecting pieces in the vicinity of the mating surface between the recuperator and the connecting pieces.

As is the case with prior art recuperators and connecting pieces, it is possible to place the channel separation entirely within the connecting piece. However, in the present configuration, it is attractive to have some of the channel walls extending transversely to the main plane of the channels connected in alignment with the plate positions of the connecting pieces at the mating surface location, and others of the channel walls extending transversely to the main plane of the channels connected via a curved portion to the plate positions of the connecting pieces at the mating surface location. This configuration allows the channel separation to be partially located within the actual recuperator, which simplifies the construction of the connecting pieces.

This embodiment also provides a method wherein, after manufacturing the recuperator, the recuperator is provided on both sides with a connecting piece by connecting the connecting pieces at the edges of its fully open surface to the edges of the connecting pieces of the recuperator.

To simplify assembly, it is preferred that the connecting pieces be connected to the recuperator by means of a form-lock connection, such as a push-in connection. The clarification above in this description also applies to this form-lock connection.

This embodiment further provides a method wherein the connecting pieces are connected to the recuperator by means of a form-locking connection.

The present invention will now be explained with reference to the attached figures, in which:

Figure 1 is a schematic perspective view partially in cross-section of a plate according to a first embodiment;

Figure 2 is a view of the entire plate, a cross-section of a detail of which is shown in Figure 1;

Figure 2A is a cross-sectional view of another detail shown in Figures 1 and 2;

Figure 3 is a view of a variant of the plate shown in Figure 2;

Figure 4 is a perspective view of a modified version of the first embodiment according to Figures 1 and 2;

Figure 4A is a cross-sectional view parallel to the longitudinal direction of the channels of a variant of the embodiment shown in Figure 4;

Figure 5 is a view of a recuperator formed by alternate stacking of the plates shown in Figures 2 and 3;

Figure 6 is a detailed schematic perspective cross-sectional view of the recuperator shown in Figure 5;

Figure 7 is a schematic perspective view of another variant of the first embodiment;

Figure 8 is a schematic perspective view of a plate according to a second embodiment; Figure 9 is a view of the plate shown in Figure 8, but which is provided with a transposed portion in the head;

Figure 10 is a cross-sectional view of a combination of two plates according to the second embodiment;

Figure 11 is a view of a two-plate assembly as shown in Figure 9;

Figure 12 is a schematic perspective view of a part of the recuperator;

Figure 13 is a schematic view of a part of the recuperator; and

Figure 14 is a detailed view of the connecting piece for use in the recuperator according to Figures 12 and 13.

Figure 1 shows a plate, designated as a whole by 1, as part of a recuperator as shown in Figure 5. The plate 1 is provided with protuberances arranged in a regular pattern and forming channels of the first type 3a. These channels 3a are surrounded by an end wall 4 and two side walls 5, 6. The channels 3a are open at the position of the main plane 1a of the plate 1. The protuberances further form channels 3b of the second type, which are enclosed between the side walls 5 and 6 and the end walls 7 at the position of the main plane 1a of the plate 1. At the position of the transition between the side walls 5, 6 and the end walls 4, the plate comprises beveled portions 8 on the outer side. The plate 1 further comprises ridges 9 protruding at the position of the transition between the side walls 5, 6 and the end walls 7.

The channels 3a and 3b are substantially trapezoidal in shape, which facilitates mold release during manufacturing. However, other shapes, such as a rectangle or a trapezoid with the wide side at the end walls, are possible. This drawing also shows side wall parts 10, in which a channel with a smaller width, i.e., preferably approximately 0.7 times the width of the other channels, is formed between the side wall parts 10 and the nearest side wall 5. In principle, other widths are also possible. The side wall part 10 is further provided with a groove 11 on one side and a tongue 12 on the other side. Arranged in the tongue 12 is a linear thickened portion 13a, while a corresponding recess 13b is arranged in a corresponding position in the groove 11, which provides a snap-fit connection during assembly.

When a quantity of such plates 1 are assembled into a recuperator, a structure is created as shown in Figure 5. It is observed here that the plates of different types have been stacked alternately, as will become clear below. This figure shows that the chamfered portions 8 of one plate 1 fit into the ridges 9 of the adjacent plate, so that the relative position of the plates 1 in the direction of the main plane of the plates is fixed transversely to the channel direction. The same effect is also obtained in the side wall pieces 10, whose tabs 12 are retained by the grooves 11 of the rear plate, where the thickened portion 13a and the recess 13b fit together and provide the snap connection and additional sealing. This figure also shows that the channels 3a, 3b in the adjacent plates are combined into channels 3 with a larger transverse measurement with double "height". This is because plates of different types are stacked alternately.

Likewise, it is possible to obtain channels with a height corresponding to the height of walls 5 and 6 by stacking identical plates together, or to obtain channels with a height corresponding to the height of walls 5 and 6 by stacking different plates together. These channels 3 have a substantially rectangular cross-section, although in Figures 1 and 4 the channels 3 resulting in this way, in addition to having rounded corners, also have a slightly greater thickness at their center than at their ends. However, it is also possible for channels 3 to have a slightly smaller thickness at their center than at their ends.

A plate 1 is shown as a whole in Figure 2. The plate 1 is provided with side wall pieces 10 extending on both sides and each having a height equal to half the height of the side walls of the channels, so that both side wall pieces together have the same working height as the channels. The plate 1 is further provided with channels 3 at the position of the actual recuperator, while the plates 1 comprise on both end surfaces of the actual recuperator a triangular extension 14a, 14b, as is known from the prior art per se. These triangular plate parts 14a and 14b are part of the connecting pieces to be formed there, which are also known as headers. These parts 14a, 14b are coupled to extensions 15 of the side wall pieces 10, which serve to seal the relevant parts of the connecting pieces so that the connecting pieces can fulfill their separating function, as is also known per se from the prior art. A snap-fit connection is drawn in the figure, although it is also possible to apply a different type of form-locking connection, such as a connection comprising a conical tongue and groove which will be wedged during insertion due to the conical shape. Otherwise, the application of other types of connection, such as by means of adhesive, solvents or ultrasonic welding, is not excluded. Since the side wall pieces 10 extend on both sides of the plate 1 in this embodiment, the triangular extensions 14 of the plate are therefore provided on both edges with an extension 15 of the side wall pieces, which extend in opposite directions.

Figure 2A shows a form-lock connection which is attractive because it requires no additional materials and is therefore simple. One of the parts to be connected 40 is provided here with a tongue 41 which has a conical shape and which has oblique sides which extend at an angle between 0° and 7° with respect to the direction of movement. The other part to be connected 42 is provided with a groove 43, which is provided with side walls which extend at the same or a slightly different angle. When the tongue 41 is inserted into the groove 43, both parts are slightly deformed, which creates a wedging force between the oblique walls of the tongue and the groove which will hold the parts together firmly enough. Of course, the geometry of the tongue and the groove must be suitable to allow insertion into each other to such an extent that the wedging force can be produced.

Figure 3 shows a plate 1 which corresponds to the plate of a second type shown in Figure 2, which corresponds to the plates of the first type elucidated above, but where the channels 3 have been shifted by half a slope to allow the channels 3a, 3b to connect to each other as shown in Figure 5. In fact, this results in the channels having a double height, as clarified above. It is attractive, although not necessary, that the plate of the second type shown in Figure 3 corresponds to the plate of the first type, which is shown in Figure 2, although rotated by 180°.

The plate according to Figure 3 also differs from that according to Figure 2 due to the presence of spacers 16, which keep the triangular extensions 14 of the plates 1 at a distance from each other. These spacers 16 also have a guiding function for the fluids flowing through the connecting pieces. It is attractive to arrange the spacers 16 so that their effect on the flow affects both fluids, for example, on one of the triangular extensions 14 of each of the plates according to Figures 2 and 3. The two plates 1 are preferably the same, and both triangular extensions 14 are provided with spacers 16. If every second plate 1 is rotated during stacking, the spacers 16 extend on the other side of the plate 1. Otherwise, it is possible to place all spacers 16 on one plate 1, wherein both triangular extensions 14 are provided on both sides with spacers 16, or to provide both types of plate (hence both manifolds) with spacers 16 on one side. It is even possible to provide a header of both types of plate with spacers 16 on both sides.

As already explained, according to a preferred embodiment, the plates 1 are preferably manufactured by injection molding. In order to carry out the injection molding process as quickly as possible while maintaining a plate of sufficient quality, the injection points must be carefully selected. They are preferably placed near the center of the plate 1. To improve the flow in the vicinity of the injection point(s), it is recommended that the plate 1 be flat in the vicinity of the injection points. The modification shown in Figure 4 meets this requirement by interrupting the profiles 5, 6, 7 in the center with a distribution strip 18 extending across the entire width of the plate. It should be noted that Figure 4 shows a modified version of the first embodiment without spacers; the modification according to Figure 4 is also possible in the variant provided with spacers. Figure 4A shows a variant in which the distribution strip 18 has a square cross-section and shows how the profiles 5, 6, 7 gradually transition into the distribution strip 18 at the connection areas 18a. This gradual transition improves the injection molding process and also keeps the fluid flow resistance at the location of the distribution strip 18 as low as possible.

When the plates of the first type according to Figure 2 and the second type according to Figure 3 are stacked alternately, a recuperator is created as shown in Figure 5. It is visible here that the extensions 15 of the side wall pieces 10 of the adjacent plates 1 are connected to each other. Therefore, these parts are preferably provided with the same groove and tongue as the side wall pieces 10. Otherwise, it is also possible not to connect the channels to each other, by shifting the adjacent plates halfway.

Figure 6 is a cross-sectional view of the embodiment shown in Figure 5. The profile here is rectangular, although it is evident that other profiles can also be applied, such as a triangular profile, a trapezoidal profile or a profile of this type which is provided with rounded corners.

However, it is also possible to assemble the recuperator by alternately stacking the flat plates 15 and the plates 1, each provided with a profile. Such a configuration is shown in Figure 7. The plates 1 present on either side of a flat plate 15 may be of the same type, but they may also be of a different type. The profiles of the plates 1, which are provided with profiles, can also be mutually aligned, although it is also possible to change the relative position of the plates provided with a profile relative to each other. The presence of the flat plates increases the material usage and thus the cost price, although a more rigid construction of the recuperator is obtained.

Figures 8-16 refer to a second embodiment. As shown in Figure 8, the plates 21 do not extend transversely to the longitudinal direction of the cross-section of the channels 3, as in the first embodiment, but parallel to the longitudinal direction of this cross-section.

These plates 21 are therefore provided with small projections 22a which, together with the projections 22b of the adjacent plates, form the short walls of the channels. As a result, these plates 21 can be easily released from the mold after the molding process. This is the case both for the plates 21 manufactured by injection molding and for the plates 21 manufactured by thermoforming. As shown in Figure 8, the projections 22a, 22b extending on either side of the plates 21 are positioned alternately to obtain the same relative placement of the channels as in the embodiment described above. It should be noted that the configuration shown in Figure 8 cannot be realized in this way by thermoforming. In thermoforming, the projections must have substantially a V-shape and should preferably all extend on one side of the plate. Figure 9 shows a flat plate 21 which results in rectangular channels.

To obtain diabolo-shaped channels, the plates are zigzag-shaped to a certain extent. As in the previous embodiment, the projections 22a, 22b may extend over the entire width of the short wall of the channel, although it is also possible for each to extend only over part of the width of this short wall and connect to a relevant projection of an adjacent plate.

These parts of the projections 21 can be connected to each other by a form-lock connection, preferably a snap connection, so that the plates 21 are connected to each other. Figure 8 shows only a small part of such a wall. The entire wall extends over the entire height of the recuperator. However, it is also possible to assemble such a wall, for example, from pieces as shown in Figure 8. Such parts can also be connected to each other by a snap connection, which provides the option of adjusting the height of the recuperator. Figure 10 shows a cross-sectional view of this second embodiment.

In this embodiment, it is not possible to simply form a connection with the connecting pieces, since the channels are mutually offset. To facilitate this connection, the projection near the boundary surface between the actual recuperator and the connecting piece is guided, on one side 23a, by the projections 22a toward an adjacent projection 22b, as shown in Figure 9, so that the channels 3 are aligned in the position of the connecting surface. Such guides 23b are also provided on the other side of the plates 21.

Figure 10 shows a cross-sectional view of a combination of two plates 21 which are arranged mirror-symmetrically relative to each other. This figure also shows that the plates 21 are provided on their upper and lower sides with wall pieces 24 which are provided with a form-locking connection, such as a snap connection, in order to assemble respectively the lower wall 24 and an upper wall (not shown in the drawing) of the actual recuperator.

Figure 11 shows two plates 21 as a whole. This figure also shows that the plates are provided with wall pieces 24.

Figure 12 shows a set of several plates 21, which essentially form the counterflow part of the actual recuperator 27.

Figure 13 shows a view of the connecting surface of the counterflow portion of a recuperator where it is to be connected to a header. The figure clearly shows the lower wall of the recuperator, which is assembled from wall pieces 24, and the side walls, which are assembled from side wall pieces 27, 28. Guides 23a and 23b are also visible.

In order to separate the fluid streams flowing through the channels, connection pieces known per se are used. Most of the currently known connection pieces are formed from plate extensions of the actual recuperator, as clarified in the current document based on the first embodiment, but such a combined embodiment seems very difficult, if not impossible, in the configuration of the second embodiment. Therefore, individual pairs of connection pieces are used, as shown in Figure 14.

Figure 14 shows a detail of a single connecting piece 30. The connecting piece 30 is provided with plates 31 extending at a distance from each other and having a substantially triangular shape. When the connecting pieces 30 are combined with the actual recuperator, these plates 31 align with the projections 22 of the counterflow part of the recuperator. Therefore, the distance between the plates 31 is equal to the distance between the projections present on either side of the plates 21 of the recuperator, which is equal to half the distance between the projections 22 located on the same side of a plate 21, these being the short walls of the channels. The plates 31 are in each case alternately connected on both short sides of the connecting piece by respective strips 32a, 32b. This creates respective openings 33a and 33b on the other short sides, with the series of openings 33a lying one above the other all connected to channels of the first type, and the other series of openings 33b lying one above the other all connected to channels of the second type in the actual recuperator. This corresponds to the connecting pieces as known from the prior art.

These connecting pieces, like the actual recuperator, can be manufactured by injection molding, preferably by injection molding parts thereof. These pieces or segments allow the height of the connecting pieces to be adjusted to the height of the actual recuperator. It should be noted here that the width of the connecting piece, like its height, is dictated by the dimensions of the actual recuperator.

Claims (15)

1. Recuperator, adapted to transfer thermal energy between two fluids, conducted through two series of thermally coupled channels (3a, 3b), keeping the fluids separated, comprising a quantity of plates (1) stacked together and extending with their main plane mutually parallel, - wherein at least some of the number of plates (1) are each provided on at least a substantial part of their surface with profiles comprising side walls (5, 6) extending in a mutually parallel direction and along a component transversely to a main plane of the plate, and mutually parallel extending channels (3a, 3b) are present between the side walls (5, 6), - wherein each plate (1) encloses on one side channels of the first type (3a) and on the other side channels of the second type (3b), - wherein the adjacent plates (1) stacked on top of each other are mutually connected at their edges extending parallel to the channels (3a, 3b); - wherein the channels (3a, 3b) present on each side of a plate (1) extend parallel; and - wherein each plate (1) is provided with profiles comprising side walls and end walls (4, 5, 6, 7), and each plate is manufactured by injection molding, characterized in that each of the side walls (5, 6) of each plate encloses one of its side channels of the first type (3a) and encloses its other side channels of the second type (3b). 2. Recuperator as claimed in claim 1, characterized in that the side walls (5,6) additionally extend along a component parallel to a longitudinal direction of the plate. 3. Recuperator as claimed in claim 2, characterized in that the thickness of the side walls (5, 6) is at least a factor of two less than the average distance between the adjacent side walls (5, 6). 4. Recovery device as claimed in any of the preceding claims, characterized in that the profiled plates (1) and the flat plates (15) are stacked alternately. 5. Recovery device as claimed in any of the preceding claims, characterized in that the profiled plates (1) are provided with at least one elongated distribution strip (18) extending transversely to the longitudinal direction of the profiles (4, 5, 6, 7), parallel to the main direction of the plate (1). 6. Recuperator as claimed in any of the preceding claims, characterized in that the profiled plates (1) comprise side wall pieces (27, 28) which extend parallel to the longitudinal direction of the profiles (4, 5, 6, 7) and form a connection with the side wall pieces (27, 28) of the adjacent plates. 7. Recuperator as claimed in claim 6, characterized in that the side wall pieces (27, 28) form a form-locking connection with the side wall pieces (27, 28) of the adjacent plates (1). 8. Recuperator as claimed in any of the preceding claims, characterized in that the plates (1) extend into connection pieces (14a, 14b) which are connected to the recuperator. 9. Recuperator as claimed in any of the preceding claims, characterized in that the recuperator is assembled from alternately stacked plates (1) of a first and second type, wherein the plates (1) of the first and second type differ from each other. 10. Recovery device as claimed in claim 9, characterized in that the plates (1) of the second type correspond to plates (1) of the first type rotated at an angle of 180° about an axis extending parallel to the longitudinal direction of the channels. 11. Recovery device as claimed in claim 10, characterized in that the channels (3a, 3b) present in the plates (1) that are located one above the other form a combined channel. 12. Recuperator as claimed in claim 1 or 2, characterized in that the width of the side walls (5, 6) is smaller than the distance between adjacent side walls (5, 6), in that the channels (3a, 3b) have an elongated cross-section and in that the main plane of the plates (1) extends substantially in the longitudinal direction of the cross-section of the channels (3a, 3b) and in that the side walls (5, 6) are formed by projections (22a, 22b) forming the walls of the channels and in that the projections (22a, 22b) of the adjacent plates are mutually connected. 13. A recuperator as claimed in claim 12, characterized in that the recuperator is coupled to connecting pieces (30) which are provided with plates (31) extending transversely to the main plane of the plates (1) of the recuperator and in that the connecting pieces (30) are formed in individual units which are both connected with their open side to an open side of the recuperator, and in that the walls of the channels (3a, 3b) extending transversely to the main plane of the channels are connected to the positions of the plates (31) of the connecting pieces (30) in the vicinity of the coupling surface between the recuperator and the connecting pieces (30). 14. Method for manufacturing a recuperator which is adapted to transfer thermal energy between two fluids conducted through two series of thermally coupled channels (3a, 3b), wherein the recuperator comprises a number of plates (1) stacked one on top of the other and extending mutually parallel, wherein at least some of the plates are each provided on at least a part of their surface with profiles (4, 5, 6, 7), which profiles are provided with side walls (5, 6) extending transversely along a component of a main plane of the plate and wherein mutually parallel extending channels (3a, 3b) are present between the side walls (5, 6), wherein each of the side walls encloses in one of its side channels of the first type (3a) and encloses in its other side channels of the second type (3b), and where adjacent plates stacked on top of each other are mutually connected at their edges extending parallel to the channels, whose method comprises the step of manufacturing at least some of the plates by means of injection molding and the subsequent step of stacking the plates thus manufactured together, characterized because, the number of plates are stacked together in such a way that the side walls (5, 6) of each plate enclose one of its side channels of the first type (3a) and enclose its other side channels of the second type (3b). 15. Method according to claim 14, characterized in that during injection molding the plates (1) are injected into a distribution strip (18) of the plates which is located between the profiles and extends transversely to the profiles.