Patent Description:
Extraction of liquid from gas, such as extraction of water from air, is well known and typically involves enforcement of condensation conditions of gas containing liquid vapor by lowering its temperature below the dew point temperature, thereby causing vapor to condensate and liquid is thereby released from the carrying gas. While this method is highly available, one major obstacle for using it, is the high amount of heat energy needed to be evacuated, in form of both latent heat of the vapor and byproduct of cooling large amount of carrying gas. The high energy cost, and the high cost of available systems often render this solution uneconomic. The energy cost for a given amount of extracted water, is an important factor in deciding to choose this solution among others.

<CIT>, discloses dehumidification apparatus including a cooled core coupled to an external cooling source, at least first and second relatively humid air inlet pathways leading to the cooled core and at least first and second relatively dry air outlet pathways leading from the cooled core, the outlet pathways being in heat exchange propinquity with the inlet pathways whereby relatively humid air in the inlet pathways is precooled upstream of the cooled core and relatively dry air in the outlet pathways is heated downstream of the cooled core, the cooled core defining a multiplicity of mutually adjacent cooling pathways extending therethrough which are each coupled to one of the inlet pathways and to one of the outlet pathways such that air passes through adjacent ones of the mutually adjacent cooling pathways in mutually different directions.

This description of embodiments of the invention depicts a heat exchanger and a method, each enable reduction in the energy consumption, and enable to reduce both operational and production costs of extraction machines from this type of solution.

Another implementation of the present invention enables to reduce energy cost in processes when heating is required, and cooling back is possible or required.

The invention relates to a heat exchanger comprising a fins and tubes heat exchanger and a plates heat exchanger, as defined in claim <NUM>. The fins and tubes heat exchanger comprises a stack of fins, the fins comprising at least one through hole coupled with a penetrating heat exchanging tube. The plates heat exchanger comprises a stack of plates, at least two sets of flow inlets and two sets of flow outlets, at least a portion of the plates each comprising a void and an embossment. Each one of at least a portion of the fins of the fins and tubes heat exchanger is at least partially attached to a corresponding plate of the plates heat exchanger to define a set of a fin and a plate (SFP), wherein the fin is at least partially overlapping a cutout of the plate, and at least a portion of a peripheral margin of the fin of the SFP being attached to and overlapping at least <NUM>% of a peripheral margin around the cutout of the plate of the SFP such that fluid flowing over either side of the plate comes into contact with the fin, and the other portions of the fin closely fit with the edges of a cutout, and wherein at least one of: (i) an alternating order of differently embossed plates; and (ii) an alternating orientation of plates in the stack, is adapted to enable one or more of (i) a simultaneous counter fluid flow, (ii) cross fluid flow or (iii) semi counter-cross fluid flow above and below the SFP. The assembly of a stack of SFPs with tubes (e.g. heat exchange fluid tubes) defines a heat exchanger of fins and tubes assembled to plates (HEFTAP).

In a second aspect, not forming part of the claimed invention, the disclosure provides a HEFTAP wherein at least a portion of the fins comprising at least one through fluid aperture allowing fluid to pass from one side of the fin to the other side.

The invention optionally further provides a HEFTAP wherein the plates comprise lateral peripheral protrusions designed to form, when the plate is stacked with another plate, at peripheral locations intended to be sealed, at least one of:.

The invention optionally further provides a HEFTAP wherein the plates comprise lateral peripheral protrusions designed to form, when the plate is stacked with another plate, at peripheral locations intended to be sealed, a gap between the peripheral protrusions and a surface of an adjacent plate facing the peripheral protrusion, being sufficiently narrow to enable the edges of the plates to melt and coalesce upon applying heat; and
wherein the plate is designed to form a gap, when the plate is stacked with another plate, between the edge of the plate and the edge of the adjacent plate facing the first plate at locations where the gap should remain open, being larger than a gap allowing the edges of the plates to melt and coalesce upon applying heat such that the gap remains open.

In another aspect, not forming part of the claimed invention, the disclosure provides a HEFTAP wherein the stack of SFPs is prepared from plates having edges that snap into each other in the sections that block the flow. To this end, lateral peripheral protrusions of the plates of the SFPs have corresponding recesses on the other plane of the plate so that when the plates are stacked protrusions of one plate enter corresponding complementary recess of the adjacent plate. In some embodiments at least part of these protrusions are designed to make contact along the wall of said corresponding complementary recess when the plates are stacked such that a continuous sealed blocking is formed along the peripheral protrusions/recesses.

The invention optionally further provides a HEFTAP comprising plates comprising a fluid inlet zone, a first heat exchanging zone comprising channel protrusions, a second heat exchanging zone, a third heat exchanging zone comprising channel protrusions and a fluid outlet zone, at least one of the fluid inlet zone and the fluid outlet zone comprising uniformizing protrusions configured to reduce the amount of non-uniform fluid mass flow between different channel protrusions in at least one of the first heat exchanging zone and the third heat exchanging zone and through the second heat exchanging zone.

In a further aspect, not forming part of the claimed invention, the disclosure provides a plate of a heat exchanger as defined in any one of the definitions above.

In a further aspect, not forming part of the claimed invention, the disclosure provides a fin comprising at least one through fluid aperture allowing fluid to pass from one side of the fin to the other side.

In a further aspect, not forming part of the claimed invention, the disclosure provides a method for selectively sealing gaps between adjacent plates of a plates heat exchanger comprising the steps:.

In a further aspect the invention provides a method for manufacturing the heat exchanger of claim <NUM> comprising the steps of:.

In a further aspect, not forming part of the claimed invention, the disclosure provides an apparatus comprising a compressor, a condenser, an expansion device and an evaporator enabling a refrigerating process wherein: the condenser is a fins and tubes heat exchanger of the HEFTAP as defined above; the evaporator is positioned downstream the heat exchanger such that airflow which exits the heat exchanger flows through the evaporator. Alternatively, the evaporator is the aforementioned fins and tubes heat exchanger, and the condenser is positioned downstream the heat exchanger and airflow which exits the heat exchanger flows through the condenser.

The present invention enables the reduction of heat consumption and may be implemented in various types of processes where cooling a fluid is required, followed by reheating at least some of it (i.e. distillation of ethanol from water-ethanol vapor mixture, solvent vapor extraction for air, humidity extraction from air, etc.). Another application of present invention relates to processes when heating the fluid is required and cooling it afterward is desirable (i.e. milk pasteurization/UHT process, air sterilization by heat, ozone disassembling by heat, etc.).

For sake of simplicity, the description mostly refers to a dehumidifier or water-from-air extraction apparatus having a heat exchanger comprising heat exchanging fluid tubes which contain a cold refrigerant, and to air as the subject fluid being treated, wherein the air is cooled to its due point, and humidity contained in the air is condensed into water. Such appartuses include air conditioners, air-dryers, dehumidifiers, water-from-air apparatuses etc..

However, one who is skilled in the art can adapt the apparatus and the method to other usages under the scope of current invention, some mentioned herein, for example: when the tubes contain a cold heat exchanging fluid; when the tubes contain hot heat exchanging fluid; when the subject fluid is different from air etc., The terms "air" and "fluid" as well as "air flow" and "fluid flow" are thus interchangeably used throughout the specification.

The inventors of the present invention have previously disclosed in <CIT> a water extracting apparatus, comprising a heat exchanger assembly, designed to allow efficient heat exchange between pre-cooled inlet air and post-heated outlet air, so that the pre-cooled inlet flow arrives to the second heat exchanger at a lower temperature where it exchanges heat with the coolant. The high heat exchange efficiency is achieved, among other features, due to the structure of the heat exchanger comprising two types of planar heat exchange elements (i.e. plates of a plates heat exchanger), comprising a void (e.g. a cutout defined by internal edges of the plates) and differing only by having two different embossment topographies, which are alternately arranged in a stack. As the cutouts are all aligned with each other, the stack of heat exchange plates defines a plates heat exchanger having a void in its center. The void in the stack of plates heat exchanger encompasses a stack of fins comprising through holes coupled to heat exchange tubes, which defines a fins and tubes heat exchanger serving as a cooled (or heated) core of the assembly, along which an air flow may pass. Fins of the fins and tubes heat exchanger are coupled to plates of the surrounding plates heat exchanger such that each fin coupled to a plate forms a "set of fin and plate (SFP)". The assembly of a stack of SFPs with tubes (e.g. heat exchange fluid tubes) defines a heat exchanger of fins and tubes assembled to plates (hereinafter "HEFTAP"). The HEFTAP may also be viewed as an assembly of a fins and tubes heat exchanger encompassed by plates heat exchanger, such that the fins and tubes heat exchanger is at the core of the assembly. During the operation of the water extraction apparatus the assembly of the plates heat exchanger surrounding the core fins and tubes heat exchanger produces interleaved, in some embodiments, counterflows of air over each other, while flowing through the fins of the core in mutually alternant directions.

Reference is made to <FIG>, which is a schematic illustration of a first SFP <NUM> that includes plate <NUM> and fin 110B, and to <FIG>, which is a schematic illustration of a second SFP <NUM> that includes plate <NUM> and another fin 110B. Reference is further made to <FIG> and <FIG> that are isometric and partially blown drawing of a pair <NUM> of SPF and HEFTAP <NUM>, respectively, wherein the HEFTAP is built from multiple SFPs <NUM> and <NUM>, and operative according to embodiment of prior art. Each SFP of the HEFTAP is a coupled pair of a plate (<NUM> and <NUM>, respectively) and a pair of fins 110B. Both plates <NUM> and <NUM> have a void in the form of a cutout accommodating the fin 110B being coupled to that plate. In the embodiment depicted in <FIG> and <FIG> the two types of plates <NUM> and <NUM> are identical except for their embossments being mirror image of each other. The embossment is configured to channel the fluid flow in a designed pathway. The mirror image embossment of plates <NUM> and <NUM> and the alternating arrangement of the SFPs <NUM> and <NUM> dictates that a fluid such as air flowing into the HEFTAP <NUM> is split into two main flows, flow A and flows B. Each flow A flows between two SFPs in front of the face of an essentially planar SFP <NUM> and behind the back face of essentially planar SFP <NUM>. Each flow B flows between two SFPs in front of the face of an essentially planar SFP <NUM> and behind the back face of next essentially planar SFP <NUM>. Flow A enters the area of SFP <NUM>, between two plates <NUM> and <NUM> (plate <NUM> which enclaves flow A is shown only in <FIG>), via fluid inlet zone 110D, then channeled over a first heat exchanging zone 110A, then between two fins 110B, through a second heat exchanging zone corresponding to fin 110B, then between two plates <NUM> through third heat exchanging zone 110C and then through air outlet zone 110E. Similarly, and in counter direction, air flow B enters the area of SFP <NUM> between two plates <NUM> and <NUM> via air inlet zone 120E, then channeled over first heat exchanging zone 120C, then between two fins through a second heat exchanging zone corresponding to fin 110B, then between two plates through third heat exchanging zone 120A and then through air outlet zone 120D.

It is noted that the zones in <FIG> are depicted as being separated from one another for sake of simplicity, in order to indicate the areas which are distinctly separated. However it should be appreciated that the spaces between the zones are part of the overlapping boundaries of two adjacent zones.

<FIG> depicts an isometric view of the combined SFPs <NUM> and <NUM>, of <FIG> placed one in front of the other to emphasize the resulting combined flows. The directed pathway of flows A and B is achieved, intra alia, due to the flow blockage protrusions <NUM> and <NUM> on the periphery of the essentially planar SFPs <NUM> and <NUM>, respectively. As is clearly seen, airflows A and B flow over each other in cross flow scheme a counter flow scheme or a semi counter-cross scheme (the term "semi counter-cross flow" means that the relative direction of two fluid flows is in between being perpendicular to being counter) in three heat exchanging zone pairs: (i) 110C and 120C, (ii) the two fins 110B of <NUM> and <NUM> and (iii) 110A and 120A. Those three zone pairs together with the inlets (110D, 120E) and outlets zones (110E, 120D) renders the heat exchange, while heat can be transferred through the plates and fins.

The passage of airflow A in front of its respective essentially planar SFP <NUM>, the passage of airflow B in front its respective essentially planar SFP <NUM>, and the way airflows A and B interact with each other are seen clearly in <FIG>. By way of example, a fluid flow A flowing from the fluid inlet zone 110D toward the second heat exchanging zone 110B exchanges heat in the first heat exchanging zone 110A with a counter, cross fluid flow or semi-cross counter fluid flow B flowing simultaneously on the other side of the plate <NUM> through the plate's surface, then the fluid flow exchanges heat with the exposed fins in the second heat exchanging zone 110B, then exchanges heat with a counter fluid flow, cross fluid flow or semi-cross counter fluid flow B on the other side of the plate <NUM> through the plate's surface in the third heat exchanging zone 110C and exits through the fluid outlet zone 110E.

Heat exchanger end plate <NUM> is also depicted (see below). The term "end plate" relates to an optional mechanical element of the HEFTAP positioned at an end of the stack of SFPs an connected thereto, enabling the adaption and/or fixation of the HEFTAP to its place.

One implementation of an improved heat exchanging unit for energy-wise efficiently, while forcing external originating heat exchanging fluid through the tubes of the fin and tubes heat exchanger, is to absorb heat from entering fluid (flows A and B), e.g. humid air, both upstream the second heat exchanger zone 110B and in the second heat exchanger zone 110B, and further on heating it back downstream the second heat exchanger zone 110B. That results in improving in the energetic efficiency of water extraction process.

Second implementation of an improved heat exchanging unit for energy-wise efficiently, while forcing hot external fluid through the tubes of the fin and tubes heat exchanger, is to heat fluids A and B, i.e. milk to be pasteurized both upstream the second heat exchanger zone 110B, and in the second heat exchanger zone 110B, and further on cooling it back downstream the second heat exchanger zone 110B. That results in improving in the economic efficiency of pasteurization process.

This invention may further involve implementing cheap materials such as plastic plates. Furthermore, volume occupation efficiency where for a given volume occupied by the energetic process to be done, with given conditions, provides larger yield with low energy consumption and lower noise level if desired.

Reference is now made to <FIG>. Leakages of fluid which leak through gaps existing between the fin and the plate, as well as gaps between blocking protrusion and the adjacent plate, contribute to reduction in the effectivity of the heat transfer because these leakages a portion of the inlet air does not fully follow the designated heat exchange pathway. For example, a leak denoted herein as "type I" <NUM> is a portion of the air flow A which arrives from the inlet zone and the first heat exchanging zone flowing over the back side of the plate, but instead of passing under the fin, passes through a gap <NUM> between the fin and the plate from one side of the plate to the other side, where it merges with a counter fluid flow B and exits the plate through the flow outlet over the front side of the plate, without substantially flowing over the fin. Another type of leak, denoted herein as "type II" <NUM>, relates to air which instead of entering as Flow B through the fluid entry zone, enters the plate through gaps between the blocking protrusions and the adjacent plate, merges with the main fluid flow B over the plate and exits the plate through the fluid outlet without effectively exchanging heat according to the designated flow pathway. Air which enters at a location downstream the second heat exchange zone, i.e. downstream the fin, may have no interaction with the fin whatsoever.

Therefore, the efficiency of the heat exchange thus depends, among other factors, on the degree of alignment of the void in the surrounding plates <NUM>, <NUM> with the corresponding fins 110B and sealing the gap between them to mitigate the deficient heat exchange caused due to the type I leakage. Mitigating the type II leakage is performed by sealing the gaps between the outer edges of blocking protrusions of one plate and the outer edges of the adjacent plate.

The inventors of the present invention found a way to facilitate the alignment of the void of the plate with the corresponding fin and the sealing of the gap between the fin and the plate by physical attachment of the fin to the plate through an overlap peripheral margin of the fin and a margin surrounding a void in the plate to which the fin is coupled. According to the invention, the void in the plate is a cutout in the plate. In some embodiments the plate is a combination of at least two sub-plates which are separated from each other and the void is the space between the at least two sub plates. In some embodiments the plate is a combination of at least two sub-plates attached to each other and the void is generated according to the outline of the edges of the sub-plates.

Reference is now made to <FIG> which are a back and front exploded view drawings of a SFP according to an embodiment of the present invention. Plate <NUM> is one plate out of a stack of plates defining a plates heat exchanger, and fin 210B is one fin out of a stack of fins of a fins and tube heat exchanger. Plate <NUM> comprises fluid inlet and outlet zones 203A and 203B, respectively, a first heat exchanger zone 205A, a second heat exchanger zone 205B comprising a cutout <NUM> defined by internal edges of the plate and having an area smaller than the area of fin 210B, and a third heat exchanger zone 205C. When stacked in the HEFTAP, the SFP functions in a similar fashion to the SFP of the prior art depicted in <FIG> but in an improved manner. In some embodiments, the cutout <NUM> is at the central area of the plate <NUM>, and in some embodiment, the cutout <NUM> can be off centered. Fin 210B comprises at least one tube through hole <NUM>. Each through hole <NUM> is adapted to accommodate and be coupled with a penetrating heat exchanging tube (not shown). The term "through hole" refers to a hole that passes from one side of the article to the other side. In some embodiments protruding flanges may extend from the circumference of the through hole. As the cutout <NUM> has a smaller area than the fin 210B, then when the fin is attached to one side of the plate to overlap with the cutout <NUM>, only a portion 214B (usually an inner portion) of the fin 210B is exposed through the cutout <NUM> to the other side of the plate, while a peripheral margin 216B of the fin 210B overlaps with a margin <NUM> surrounding the cutout <NUM>. Consequently, fluid (e.g. air) flowing over either side of the plate <NUM> comes in direct contact with the fin 210B. The overlap between the margins of the fin and the plate facilitates the sealing between the fin and the plate and reduces the chance leakages that occurred in the prior art SFP, where the fin had to fit to the cutout in the plate. The wider the overlapping margin the more effective is the sealing between the fin and the plate and the more robust is the coupling of the two. On the other hand, a wider overlapping margin narrows the area of the exposed fin, which is where the most effective heat transfer occurs. In some embodiments, the overlapping margin 216B is between <NUM> to <NUM> wide in order to reduce type I leakages between flows A and B in the overlapping margin of the plate and the fin. In some embodiments, the overlapping margin 216B is at least <NUM> to <NUM> wide. In some embodiments, the overlapping margin 216B is at least <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM> wide.

According to the invention, a portion of the periphery of the of the fin overlaps with the surface of the plate while other portions closely fit with the edges of the cutout. Between <NUM>% to <NUM>% of the periphery of the fin is overlapping with the surface of the paired plate when the plate and fin are coupled to each other. In some embodiments at least <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>% or <NUM>% of the periphery of the fin is overlapping with the surface of the paired plate when the plate and fin are coupled to each other.

The cutout <NUM> accommodates a portion 214B of the fin 210B comprising at least one heat exchanging tube. In the embodiment depicted in <FIG> cutout <NUM> accommodates the entire area of the fin 210B comprising the tube holes <NUM>. In some embodiments, the portion of the fin 214B is slightly elevated from the plane of the peripheral margin 216B so when the fin is attached to the plate, the portion 214B is coplanar with the plate <NUM>. In some embodiments when the portion 214B is elevated it facilitates locating fin 210B properly in the cutout <NUM>. In some embodiments, the margin <NUM> is slightly elevated from the main plane of the plate (in some embodiments by <NUM>-<NUM>) to facilitate the placement of the fin 210B in the cutout <NUM>.

According to the invention, the fin 210B is adhered to the surface of the coupled plate <NUM>. In some embodiments, an adhesive is applied to the overlapping margin 216B of the fin 210B, to the overlapping margin <NUM> of the plate <NUM> surrounding the cutout <NUM> or applied to both. In some embodiments adhesive is applied over the boundary line between the fin 210B and the plate <NUM> when the fin and plate are attached to each other.

In some embodiments the overlapping margin <NUM> comprises a groove being complementary to a protrusion in the margin 216B of the fin or vice versa, such that when the fin and the plate are attached the protrusion resides in the complementary groove.

Plate <NUM> is embossed to channel a fluid flow from an inlet zone to a first heat exchanging zone over the plate then to a second heat exchanging zone between two fins, then through a third heat exchanging zone over the plate and then through a fluid outlet zone. In some embodiments as explained above, there are two possible mirror images of embossments, such that when the two plates are stacked in an alternating fashion counter flow of fluid above and below the plate is obtained. In some embodiments, the same embossment produces a fluid flow to a different direction due to a different orientation of the plate relative to the longitudinal axis of the stack of plates.

It is noted that the term "between the heat exchanging zones" relates to a zone inclusive of the plates and fins themselves as heat exchanging takes place on the fins and on the plates as well.

In some embodiments, the plates are made of low heat-conductive material such as plastic, and the fins (as well as the tubes) are made of a high heat conductive material such as a metal or metal alloy. In some embodiments, the plates are made of a material having a thermal conductivity coefficient of less than <MAT>, in some embodiments less than <NUM> <MAT>, in some embodiments less than <MAT>, in some embodiments less than <MAT>. In some embodiments, the fins are made of a material having a thermal conductivity coefficient higher than <MAT>, in some embodiments higher than <MAT>, in some embodiments higher than <NUM> <MAT>. The advantage of using a low heat conductive material for the plates and a high heat conductive material for the fins is explained in <CIT>. In some embodiments the fin and/or the tube are made of aluminum, aluminum alloy, copper, copper alloy, or stainless steel. In some embodiments the plates are made of polyethylene terephthalate, in some embodiments the plates made from polystyrene.

In some embodiments, the plate comprises attaching protrusions <NUM> dispersed in the peripheral margin area <NUM> surrounding the cutout <NUM> which overlaps the peripheral margin 216B of the fin for pressing the fin 210B to an adjacent plate or to the same plate <NUM> as will be discussed in more detail later.

The invention provides a HEFTAP comprising a stack of the SFPs as defined above. Having the SFPs stacked and aligned, obtains a HEFTAP comprising a fins and tubes heat exchanger and a plates heat exchanger wherein at least a portion of the fins of the fins and tubes heat exchanger being at least partially attached to plates of the plates heat exchanger. In some embodiments, some of the fins and/or plates remain uncoupled. In some embodiments fins of the fin and tubes heat exchanger are attached to the plates on all sides of the fin. In some embodiments a portion of the edges of the fin is unattached to the plate.

Each one of at least a portion of the fins being at least partially attached to a plate to define a SFP wherein the fin is at least partially hermetically overlapping the void of the plate, and at least a portion of a peripheral margin of the fin being attached to a portion of a peripheral margin around the void of the plate such that fluid flowing over either side of the plate comes in contact with the fin.

According to some embodiments at least one of: (i) an alternating order of differently embossed plates; and (ii) an alternating orientation of plates in the stack (relative to the longitudinal axis of the stack), is adapted to enable a simultaneous counter fluid flow, cross fluid flow or semi counter-cross fluid flow above and below the SFP. In some embodiments a pair of SFPs enables a fluid flow scheme which is a combination of at least two of a counter fluid flow, a cross fluid flow and a semi counter-cross fluid flow. For example, in the pair of SFPs depicted in <FIG> there is a cross fluid flow between the inlet and the outlet regions, a counter flow between the fins and combination of counter fluid flow and semi cross-counter fluid flow in between the first and third regions. In some embodiments the stack of SFPs can enable in the same HEFTAP more than one of a simultaneous counter fluid flow, cross fluid flow or semi counter-cross fluid flow above and below the SFP. To this end the stack comprises at least two pairs of adjacent SFPs each providing one of a counter fluid flow, cross fluid flow or semi counter-cross fluid flow, wherein each pair provides a different type of fluid flow. For example, at least one pair of adjacent SFPs provides a counter fluid flow while at least one other pair of SFPs provides a cross fluid flow.

Due to the overlap between the fins and plates an improved HEFTAP is obtained in comparison to the HEFTAP of the prior art, characterized by having fewer air leaks, more efficient heat exchange and increased structural durability and intactness.

In some embodiments an alternating order of differently embossed plates is adapted to enable a concomitant counter fluid flow, a cross fluid flow or a semi-cross counter fluid flow in front and behind the plate, and provides the HEFTAP with at least two sets of flow inlets and two sets of flow outlets, as demonstrated in <CIT> or further herein.

In some embodiments, an alternating orientation of plates in the stack is adapted to enable relatively counter fluid flow in front and behind the plate. For example, in some embodiments, the plates have a single embossment design which when stacked in a head to tail arrangement enable the desired counter fluid flow.

Reference is now made to <FIG> depicting a front view of a SPF made of a plate <NUM> coupled to a fin <NUM> according to an embodiment of yet another aspect of the present invention.

Each SPF, which is defined as the combination of a plate <NUM> and a fin <NUM>, comprises three heat exchanging zones 305A, 305B and 305C. Heat exchanging zone 305B generally corresponds to the exposed portion of the fin <NUM> through the cutout of the plate <NUM>. Heat exchanging zones 305A and 305C generally correspond to the areas of the plate which are located upstream and downstream with respect to the direction of flow of fluid over the SPF of heat exchanging zone 305B on each side, respectively. The three heat exchanging zones 305A, 305B, and 305C are continuously engaged with each other according to said order (i.e. heat exchanging zone 305A is in contact with heat exchanging zone 305B, and the latter is also in contact with heat exchanging zone 305C).

In some embodiments, along the perimeter of the cutout in proximity thereto are disposed groups of attaching protrusions <NUM>, adapted to keep a next fin attached to a peripheral margin around a cutout of the next plate or of the same plate and to reduce or eliminate the gap between the next fin and the next plate (i.e. by "pushing" the next fin towards the next plate of the next SPF). The attaching protrusions <NUM> are also designed to allow air flow to pass through from the first heat exchanger zone 305A to the second heat exchanger zone 305B and from the second heat exchanger zone 305B to the third heat exchanger zone 305C. To this end, according to some embodiments the attaching protrusions <NUM> are designed as groups of separated dot-like protrusions. In some embodiments as depicted in <FIG>, the attaching protrusions <NUM> are disposed on the surface of the plate <NUM> opposite to the surface to which the fin of the SFP is attached.

According to some embodiments, the attaching protrusions are disposed on the surface of the plate to which the fin is supposed to be attached. In these embodiments, the protrusions comprise a snatching groove (not shown) designed to attach the fin in close contact to the plate while keeping a distance from the next plate of the next SFP. The fin can snatch into the groove on its edges or through complementary holes within its surface.

In some embodiments, the attachment protrusions are dispersed on the peripheral margin of the fin (not shown), in addition to, or substituting, the attachment protrusions dispersed on the plate or to substitute these protrusions. In some of these embodiments, the attachment protrusions are directed to one side. In some embodiments, the attachment protrusions comprise a groove to enable snatching of the protrusions with the surface of the plate once the protrusions are pressed through a complementary aperture in the surface of the plate.

The inventors of the present invention have found that increase of heat exchange efficiency in a heat exchanger constructed from the heat exchanging plates complying to the general structure detailed above, is obtained by designing embossment of uniformizing protrusions <NUM> in the fluid inlet zone 303A and/or in the fluid outlet zone 303B. Those protrusions are configured to reduce the amount of non-uniform fluid mass flow between different channel protrusions <NUM> in the first and in the third heat exchanging zones, 305A and 305C, respectively (i.e. to reduce the variance in fluid mass flow at one channel in comparison with another channel in the same heat exchanging zone), and along the second heat exchanging zone 305B over fin <NUM>. In some embodiments, where one of the first or third heat exchanging zones lack channel protrusions <NUM>, the uniformizing protrusions reduce the amount of non-uniform fluid mass flow between different channel protrusions <NUM> in the heat exchanging zone having channel protrusions. The channel protrusions <NUM> are set of parallel longitudinal evenly dispersed protrusions, which channel the fluid flow from the entry to the second heat exchanging zone to its exit or from the entry to the third heat exchanging zone to its exit. to the entry. The inventors have further found that uniformity of the fluid mass flow along the channels <NUM> (i.e., that different channels in the same zone have the same or closely the same mass flow) in the first and third heat exchanging zones 305A and 305C, respectively, can be further optimized by adjusting the shape of the channels <NUM>, their respective location and the distances between adjacent channels on the plate <NUM>. In some embodiments, fluid flow channels in at least one of the first and third heat exchanging zones comprise at least one bent line protrusion in proximity to the inlet or outlet zone, respectively.

In some embodiments the topology of uniformizing protrusions <NUM> in the fluid entry and/or fluid outlet zones 303A and 303B, respectively, comprises at least one, in some embodiments at least two of a straight line protrusion 306A a bent line protrusion 306B, a dot protrusion 306C, unevenly spaced protrusion lines, non-parallel protrusion lines, non-aligned starting points and non-aligned end points. In some embodiments, the broken line protrusion is selected from at least one of a L-shaped and a S-shaped line.

The effectiveness of the aforementioned topology of the uniformizing protrusions towards a more uniform mass flow is evaluated by running computerized fluid dynamics (CFD) simulations which are performed on the full design of the SFP being sandwiched between two adjacent SFPs. According to the results of the simulation, the person of skill in the art can modify the initial topology and rerun a CFD simulation in order to determine whether the modification reduces the non-uniformity mass flow in the first and/or in the third heat exchanging zones, 305A and 305C, respectively, and/or along the second heat exchanging zone 305B over fin <NUM>. Such modifications may include elongation of protrusion lines, altering curves, changing the protrusion height, changing the angle of attack of the protrusion, changing a space or relative angle between two protrusions and so on. By running several iterations of modifications of the topology and CFD simulations an optimized topology is obtained. In some embodiments, the CFD application can automatically perform fine tuning optimization of a given topology to achieve said reduction in the non-uniformity mass flow.

In some embodiments, the uniformizing protrusions are designed to provide a uniform fluid mass flow, or at least reduce the deviation of the mass flows along the channel protrusions <NUM> in the first and/or third heat exchanging zones 305A and/or 305C, respectively, and/or along the second heat exchanging zone 305B over fin <NUM>, in some embodiments even in cases when the direction of the flow is reversed, i.e. when the fluid flows from zone 303B to zone 303A. In some embodiments the channeling protrusions are designed to reduce the deviation of the mass flows, for example by introducing a bend in proximity to the inlet and/or outlet zone (not shown).

The term "uniform fluid mass flow" refers to maximum mass flow rate deviation of <NUM>%, in some embodiments <NUM>% or <NUM>%, from the mean flow rate along at least <NUM>%, in some embodiments at least <NUM>%, <NUM>% or <NUM>%, of the channels in the heat exchanger zone 305A or 305B.

Reference is made to <FIG>, which depict a front view of a fin <NUM> of a fins and tubes heat exchanger; a side view of that fin; local cross section of fin <NUM> along line A-A; isometric view of that fin; local cross section of fin <NUM> along line B-B; and enlarged partial view of fin's side view, respectively, according to embodiments of another aspect of the present invention.

In order to improve the heat exchange factor between the counter flow air streams above and below each surface, and in order to provide means for equalizing air pressure between the various air flows, in particular counter or cross air flows above and below the same fin, a series of through fluid apertures (with respect to the main plane of the fin) 404A may be perforated in fins <NUM> of the fins and tubes heat exchanger, allowing fluid passing through from one side of the fin <NUM> to its other side. The term "through fluid apertures" should be distinguished from the through holes mentioned previously which are supposed to be coupled with a heat exchanging fluid when the heat exchanger is assembled and do not enable flow of treated fluid (e.g. air) through them, whereas the through fluid apertures remain open for the treated fluid to pass from one side of the fin to the other side, when the heat exchanger is assembled and operating.

In some embodiments, the through apertures 404A are bypassed by a protrusion 404B. For example, in the embodiment depicted in <FIG> the apertures <NUM> are in the form of hollow dents having apertures 404A bypassed by protrusions 404B which are all perforated to the same direction with respect to the main plane of the fin <NUM>. The apertures 404A and the bypassing protrusions 404B can be formed, for example, by using a respective punching tool. In some embodiments, the perforations may be distributed above and below the plane of the fin. In other embodiments, the apertures are holes in the fin without a perforation bypassing the aperture. In some embodiments, the through apertures are essentially located in an area in which the differential static pressure between two sides of a fin lacking the apertures and having an air flow flowing from first inlet to first outlet and had a second airflow flowing from second inlet to second outlet, is approximately equal, and in some embodiments less than <NUM>%, in some embodiments less than <NUM>%, and in some embodiments less than <NUM>%, of the pressure drop between the inlet and the outlet. The term "approximately" refers herein to a deviation of up to <NUM>% from the value to it relates to. In some embodiments the through fluid apertures are essentially aligned with a straight or curved line in which the differential static pressure between two sides of the fin is minimal. In some embodiments, the aforementioned differential pressure is less than <NUM>%, in some embodiments less than <NUM>%, in some embodiments less than <NUM>% of the pressure drop between the opposite streamlines on both sides of the fin, if the fin had not comprised the apertures. The term "essentially aligned" as used herein means that the location of the center of an aperture deviates from the aforementioned line by up to <NUM>, in some embodiments up to <NUM> or up to <NUM>, in some embodiments up to <NUM>%, <NUM>%, <NUM>%, <NUM>% or <NUM>% of the length of the streamline over the fin and the plate. In some embodiments this line is determined according to computerized fluid dynamics (CFD) simulation which is performed on the airflows flowing between at least three sequential adjacent SPFs. The person of skill in the art would know how to perform a CFD simulation and find the equal air pressure line.

In some embodiments, the fin comprising the through fluid apertures is also having an area being larger than the area of the cutout of the coupled plate.

In some embodiments the heat exchange tube holes <NUM> are evenly distributed about the at least one through fluid aperture. In some embodiments at least two cooled fluid tube holes are evenly distributed about the at least one through fluid aperture.

Heat exchanging fluid tube hole <NUM> is made to accommodate penetrating heat exchanging fluid tubes (not shown). As seen in <FIG>, grey arrow <NUM> depicts schematically a possible path of fluid for flowing through aperture <NUM> from the back face of fin <NUM> to its front face (and vice versa).

Reference is made to <FIG>. HEFTAP <NUM> comprises an alternately stacked set of SFPs 301A and 301B, each SFP defined by a paired plate (302A or 302B) and fin <NUM>, and which are arranged alternately in an interchanging order as explained above. In some embodiments, SFPs 301A and 301B differ from each other by the essentially mirror image embossment of their respective plates 302A and 302B or at least by having an essentially mirror image of the flow pattern that they channel when stacked. The plates 302A and 302B comply with the general structure of having a fluid inlet zone 303A, a first heat exchanger zone 305A a second heat exchanger zone 305B comprising cutout region defined by a cutout curve <NUM>, a third heat exchanging zone 305C and a fluid outlet zone 303B. The plate and the fin of each SFP are adjacently attached to each other at the cutout region of SFPs 301A and 301B through a peripheral margin of the fin <NUM> overlapping with a peripheral margin around the cutout of the plate.

Air flow 510A is a first air stream entering HEFTAP <NUM>. Air flow 510B is a second air stream entering HEFTAP <NUM>. Air flow 510C is a third air stream, leaving HEFTAP <NUM> and air flow 510D is a fourth air stream, leaving HEFTAP <NUM>.

The structure of HEFTAP <NUM> is designed to form a triple heat exchanging device. Reference is made specifically to <FIG> which depicts the various air streams flowing between fins <NUM> of HEFTAP <NUM> when the HEFTAP <NUM> is operating. <FIG> depicts top partial and local cross section through HEFTAP <NUM> and along cross section line AA in <FIG>.

Airstream <NUM> is a first air stream originating from 510A which passes through first heat exchanger zone 305A, flowing between plates 302A and 302B, then through part of the first portion of second heat exchanger zone 305B flowing mainly between the fins <NUM> and then, at dent <NUM>, at least first and second sub-flows 551A and 552A split from first air stream <NUM>, while portion of first air stream 551A continues forward to merge with fourth air stream <NUM>, as is explained herein below.

Airstream <NUM> is a second air stream, originated from 510B, which passes through third heat exchanger zone 305C, flowing between the plates 302A and 302B, then through part of the second heat exchanger zone 305B between the fins. At dent <NUM>, the stream splits at least into a third and a fourth sub-flows 553A and 554A, respectively, while portion of second air stream 553A continues forward to merge into third air stream <NUM>, as is explained herein below.

Second and third sub-flows 552A, 553A, unite to form third air stream <NUM> which flows over the first portion of second heat exchanger zone 305B mainly between the fins <NUM>, then flows in the first heat exchanger zone 305A in an opposite direction with respect to the first airstream <NUM>, and exits the HEFTAP as flow 510C.

First and fourth sub-flows 551A and 554A, are united to form airstream <NUM> which flows over part of said second zone 305B of the second SFP, then flows in the third zone 305C of the SFP in a different direction with respect to airstream <NUM>, and exits the HEFTAP as flow 510D.

Airstreams flowing over the opposite side of each fin <NUM> are flowing in opposite directions with respect to each other.

The first zone 305A of the SFP 301A or SFP 301B is designated to exchange heat between the first airstream <NUM> and the third airstream <NUM>. The third zone 305C of the HEFTAP is designated to exchange heat between airstream <NUM> and airstream <NUM>. The second heat exchanger zone 305B is designated to cool or heat - depending on the application of the heat exchanger. In some embodiment, the second heat exchanger zone 305B is hot, for example, for pasteurization. the airstreams and the sub-flows by external cooling (or heating) fluid, originated from outside of the HEFTAP.

Without being bound to theory, the dents, together with the counter-flow/cross flow/semi-counter cross flow scheme in the fin <NUM> (i) mix the flows and renew the boundary layer of the flow. By doing so, the heat convection factor between the fins and the flows (and in some embodiments also between the plates and the flows) is increased; (ii) reduce the deviation of the mass flow rates on both sides of first heat exchanger zone 305A; and (iii) reduce the deviation of the mass flow rates on both sides of <NUM>rd heat exchanger zone 305C.

As previously described, the high efficient heat transfer relies on the lateral (i.e. along the axis of the heat exchanger perpendicular to the stack of SFPs) counter flow or cross flow or the partially cross-counter flows of fluid, in particular air, over adjacent passages on either side of each SFP of the HEFTAP. Sub-flow crossing <NUM> from flow 510A over to the adjacent flow 510C on the other side of the SFP (and/or 510D in some designs) occurring before about halfway of the flow in the second heat-exchanger zone 305B (type I leakage) and/or leakages between flows 510B and 510D (and/or 510C in some designs) occurring before about halfway of the flow in the second heat exchanging zone 305B might have different effects: (i) in order to pass a given amount of airflow through first heat exchanger zone 305A and third heat exchanger zone 305C, the total capacity of airflows 510A and 510B should be increased to compensate for such leakages, a fact that increases the total noise of the system and sometimes even the energy consumption; (ii) if the leakages of flow 510A and flow 510B are not relatively even, each of the heat exchanger zones 305A and 305B will lose efficiency (iii) the leakage, on the other hand can be attended, by increasing flows 510C and 510D in order to keep flow through heat exchanger zone 305B as desired (although the noise level increases).

The counter flow of the HEFTAP is made possible due to selective zones of blocking and opening of fluid passages between pairs of adjacent relatively planar SFPs comprising embossed plates coupled to fins. The inventors of the present invention have found that in the preparation of a HEFTAP, such as the one disclosed in the present invention, gaps between adjacent stacked plates comprising peripheral lateral embossment having protrusions with the proper height, can be efficiently and selectively sealed at specific locations intended to be blocked for fluid passage while locations intended to be open for fluid flow remain open by unselectively applying an adhesive to a face of the HEFTAP, exposing said protrusions.

To this end, in some embodiment of the invention, the HEFTAP comprises at least one plate with lateral peripheral protrusions wherein said plate is designed to form, at peripheral locations intended to be sealed when the plate is stacked with another plate, at least one of:.

In some embodiments of present invention, the plate is designed to form a gap between the edge of the plate and the edge of the adjacent plate facing the first plate at locations where the gap should remain open (for example- inlets and outlets). Said gap should be larger than a gap allowing an applied adhesive to fill or to encircle the gap such that the gap remains open.

The term "lateral" means in a direction perpendicular to the main plane of the referred object. In the context of the lateral peripheral protrusions, the wording refers to protrusions being in direction perpendicular to the main plane of the plate, such that when the plate is stacked together with the plates, the lateral protrusion fills at least part of the gap between two adjacent plates. In some embodiments, the peripheral protrusions may additionally have a parallel extension, e.g. outward from the main circumference boundary of the plate.

In some embodiments, the plate having the peripheral protrusions as explained above is coupled with a fin to form a SFP according to the invention and the SFPs are stacked to form a HEFTAP according to the invention or as previously described in <CIT>.

In some embodiments, the locations at which the gap between two adjacent SFPs should remain open to fluid flow and locations at which they should be sealed reside on the same side of the plate. In some embodiments they reside on the same face of the HEFTAP.

In embodiments where adhesive fills the gap at the edge between two adjacent plates, it is not necessarily needed to fill the entire gap between the plates from the edge inwards with adhesive. The extent to which the adhesive should fill the plate depends on many factors, including the properties of plates used, in particular the hydrophobicity, roughness and surface tension of the surface, the size and weight of the plates, the application of the heat exchanger, and the type of adhesive used. In some embodiments, where the plates are PVC plates the gap between the plates is sealed by the adhesive at the edge by <NUM> to <NUM> inwards from the circumference of the plates.

In some embodiments, the gaps are designed to be selectively sealed by heat instead of using an adhesive. To this end, the plates comprise lateral protrusions designed to form sufficiently narrow gaps between the edge of the plate and the edge of the adjacent plate facing the first plate, at locations intended to be sealed, to enable the edges of the plates to melt and coalesce upon applying heat, and at locations intended to remain open, the gaps between the edge of the plate and the edge of the adjacent plate facing the first plate should be wider than a gap allowing the edges of the plates to melt and coalesce upon applying heat. This same principle may be applied when ultrasonic welding is used. The exact size of gap at each location is dependent on the type of material at said location, its width and the heat that is applied. However, the person of skill in the art would be able, given these parameters to design the plates and the means and method for applying selective sealing accordingly.

Other means for selective sealing using this principle of having narrow vs. wide gaps are also within the scope of this invention, for example, sealing with ultrasonic welding.

With reference to <FIG>, and <FIG>, the peripheral protrusions 308A-308D are laterally extending from the surface of the plate on the edge of the plate. The protrusions 308A-308D are located at locations which are supposed to block air flow from entering into the gap between the plate and an adjacent plate. The sides of the protrusions 308A-308D which are perpendicular to the surface of the plate, are supposed to function as blockage for air flow along the portion of the edge at which they are located. Concomitantly, portions 308E and 308F of the edge of the plate 301A and the back of plate 301B define a passageway 312A which is supposed to allow air flow to enter or exit the gap between the aforementioned two plates. Similarly, the corresponding portions on plate 301B and the back of plate 301A define a passageway, or gap, 312B.

Reference is now made to <FIG>. As previously explained, in order to increase the efficiency of the counter airflow formation and reduce air leakage, the gaps <NUM> between the top of the protrusions 308A-308D (the side of the protrusions facing the adjacent plate) and the surface of said plate are sealed with a sealant. When using an adhesive as the sealant, or when the gaps are sealed by applying heat, an additional objective is met, namely adhering the plates to each other increases the robustness of the stack of plates. Much care had to be given when applying an adhesive to seal these gaps without accidently blocking the gaps which should remain open for air flow (e.g. between the portion 308E of the edge of the plate 302A and the adjacent plate 302B).

The inventors of the present invention have found that if (i) the gap <NUM> (<FIG>) between the top of the protrusions 308A-D and the adjacent plate is within the range to allow wicking of adhesive <NUM> into the gap <NUM> or (ii) the outer lateral width of the two plates at locations to be sealed is small enough to allow the adhesive to encircle <NUM> the outer edges of the plates at said locations, or (iii) both - to wick into the gap and to encircle it <NUM>, then adhesive may be unselectively applied to an entire face <NUM> of the HEFTAP <NUM> (<FIG>) and obtain selective sealing only at the blocked locations <NUM> while leaving inlets and outlets open (<FIG>), on condition that gaps such as 312A or 312B (see also <FIG>) defining fluid flow outlet or inlet, respectively are large enough to avoid the adhesive from adhering to the both bottom and top surfaces defining said entry. For comparison, face <NUM> of the HEFTAP <NUM> is to be completely sealed. In some embodiments, gap 312A or 312B is at least the size of a drop of the adhesive being formed when dropped on a surface made of the same material of surface of the plate 302A and 302B. On the other hand, the maximal gap at locations intended to be blocked for fluid flow should be smaller than the diameter of said drop. In some embodiments the lateral peripheral protrusions 308A-D are all equal and determine the highest protrusions on the plate 302A. Thus when two adjacent plates are stacked together, the height of protrusions 308A-D determines the height of gaps 312A 312B. In such embodiments, the height of the protrusions 308A-D should be at least the size of a drop of the adhesive being formed when dropped on a surface made of the same material of surface of the plate 302A and 302B. In some embodiments the adhesive forms a convex meniscus between the plates and in some it forms a concave meniscus. In some embodiment, a different type of adhesive is applied when selective sealing is required and when non-selective sealing is required.

The exact dimensions of the gaps, which are required for efficient selective sealing of the locations, which need to be sealed as opposed to locations which are required to remain un-sealed, are dependent on the type of material from which the plates are made of, the sealant/adhesive used, the diluting solvent and the concentration of the sealant/adhesive. The aforementioned dimensions can be determined by a person skilled in the art for each specific case. Without being limited thereto, when the adhesive applied to gaps between PVC plates is Gray Galvanizing Totgum paint obtained from Denber Paints and Coatings Sderot Israel (Cat. No. <NUM>), and diluted by toluene/white spirit mixture (D-<NUM> obtained from Denber Paints and Coatings Sderot Israel) at an adhesive to diluent ratio of between <NUM>:<NUM> to <NUM>:<NUM>, the gap at locations intended to be blocked for fluid flow can be up to <NUM>, and the gap at locations intended to be open for fluid flow is at least <NUM>. In the aforementioned example, the adhesive is applied by brushing at room temperature and is dried by applying a heat at about <NUM>.

In some embodiments, where the gap between edges of two adjacent plates is small enough and the capillary factor of the used sealant allows this, the straight face <NUM> of the HEFTAP <NUM> (<FIG>) may be fully submerged in a liquidized sealant and be pulled out, and the capillarity of the sealant will cause it to hermetically fill and close the gaps between the plates in an efficient manner. In some embodiments, when a convex face <NUM> is treated, it is submerged sequentially in the liquidized sealant from one end of the face to the other end in a rate which allows the liquidized sealant to hermetically fill and close the gaps between the edges which are small enough and intended to be sealed. In some embodiments having a curved concave face the face is treated by other means such as brushing with a brush.

In some embodiments, instead of applying a sealant or an adhesive, the edges of the plates are heated such that small gaps coalesce and close the gap while large gaps remain open. Here again, trial and error experiments can determine the minimal required gap to keep the passages open, and the maximal gap which results in the coalescence of the edges, which depends on the type of material the plates are made of, the applied temperature and duration of applying heat. In some embodiments the gaps are coalesced by ultrasonic welding.

In some embodiments, an end plate is placed on the assembling surface prior to placing the first fin, and the first fin is laid on top of said end plate (<NUM>). In that case, the end plate comprises at least one through hole adapted to allow heat exchange fluid tubes to penetrate the plate.

The relative dimensions of the fin and the corresponding cutout of the plate according to the present invention dictate the method for producing a HEFTAP comprising the fin and the plate. Reference is now made to <FIG> depicting a flow chart describing a method for producing a HEFTAP according to the invention. A first fin according to the invention is laid on top of an assembling surface (<NUM>).

In some embodiments, prior to placement of the first fin, at least two longitudinal guiding tubes or rods are inserted through the through holes of the end plate (and in some embodiments the end plate is inserted through said guiding tubes or rods), and the fin is laid thereafter on top of the end plate (<NUM>) through the longitudinal tubes which act as guides for placing the fin (and the plate to follow) in the right place. In some embodiments the tubes are heat exchange fluid tubes. In some embodiments the at least two tubes are replaced by cylindrical guiding rods. In some embodiments, the end plate comprises peripheral sidewalls being lateral to the main plane of the plate adapted to confine the first layers of heat exchanging plates within the space defined by said walls. In some embodiments, the end plate comprises sidewalls being lateral to the main plane of the plate and extending away from the fin defining a housing for the connections between the longitudinal tubes. In some embodiments a jig having a complementary structure is used as an aligning aid for stacking the fins and the plates (and optionally the end plate).

In some embodiments an adhesive is applied to edges of the fin on the side facing the end plate.

A first plate of a heat exchanger according to the invention is placed on the first fin of a heat exchanger (<NUM>). The plate is placed with the face of the plate which should be in contact with the fin that was placed in the preceding step facing the fin, i.e. faced down (the term "down" is used herein for sake of convenience, with reference to an embodiment where the assembly is performed vertically. However, one should appreciate that other alternatives are available such as horizontally). The plate is positioned over the fin such that the void (or cutout) of the plate overlaps a portion of the fin. In some embodiments the cutout of the plate overlaps a portion of the fin comprising at least one through hole for heat exchange tubes. When relevant, the cutout additionally encompasses the tubes which erect from the assembling surface. In some embodiments, the fin is adhered to the plate. In order to adhere the fin to the plate, an adhesive is applied over sections of the peripheral margin around the cutout prior to placing the plate. In some embodiments, the adhesive is applied over the margin of the fin to come in contact with the plate. The adhesive can be applied by common practiced methods known in the art, for example a strip or a plurality of strips of thermally active adhesive may be laid which would later be activated by heating the stack with a heater.

In embodiments in which the plate and/or the fin comprise attaching protrusions and corresponding grooves designed to attach the fin and the plate by snapping, adequate force is applied in order to have the fin snapped in place.

A set comprising a fin of a fins and tubes heat exchanger coupled to a plate of a plates heat exchanger (SFP) is thus obtained.

A new fin is placed over the plate laid in the previous step such that through tube holes of the fins are aligned to enable insertion of heat exchange fluid tubes through the holes at a later stage (<NUM>). In some embodiments, the plate comprises attaching protrusions designed to face the next fin and attach the next fin to the next plate. In embodiments where these attaching protrusions comprise a groove for snapping the next fin into place, mild force is applied to the second fin to snap it in said grooves.

A new plate is placed over the fin laid in the previous step (<NUM>). In some embodiments the plate is placed such that it is fully aligned with the first plate. In embodiments in which an alternating arrangement of the plates is responsible for a counter/cross flow (or semi counter-cross) above and below each plate, plates of different embossment are alternately stacked. To this end, a plate having a second type of embossment (for example a mirror image of the embossment of the first plate) is placed over the fin at this stage. Care is given to placing the plate facing at the right direction for enabling the counter/cross (or semi counter-cross) airflow. In embodiments wherein the horizontal positioning of the plate accounts for the counter airflow, care is given to place the plate in the correct orientation.

In some embodiments, instead of alternately inserting plates and fins, the plates are first coupled to fins to obtain SFPs and the pre-assembled SFPs are inserted through the longitudinal tubes to obtain a stack of SFPs. In such embodiments, the SFPs are inserted in an alternating sequence of SPFs of having plates of different embossment or in an alternated orientation as applicable for producing a counter/cross flow (or semi counter-cross) above and below each plate,.

Steps <NUM> to <NUM> are repeated until a stack of heat exchange SFPs at the desired length is obtained (<NUM>). The length of the stack is derived from the corresponding application of the HEFTAP in the apparatus in which it is installed. The skilled artisan would know to define this length accordingly.

In some embodiments, the stacking is performed in a reverse order, beginning first with laying a plate followed by a fin and so forth.

In some embodiments, an end plate covers the top heat exchange plate (<NUM>). In some embodiments, the stack is compressed and the compressed state is affixed by connecting the two end plates to at least one fixating connecting rod.

In some embodiments, the end plates are also assembled to the stack, for example to the top and/or bottom fin or plate, by connecting means such as bolts.

Heat exchange fluid tubes are inserted through the tube holes in the fins (<NUM>). In embodiments where some heat exchange fluid tubes where inserted as guiding tubes at the preliminary step, then only the remaining tubes are inserted at this stage. In some embodiments all longitudinally heat exchange tubes are inserted through the first end plate, nullifying this step. In some embodiments the tubes are slightly smaller in diameter than the holes and after their insertion thereto, the tubes are blown to expand and fit tightly in the accommodating holes. In some embodiments, the tube is being blown after the assembly of the HEFTAP in order to increase the heat transfer area between the fin and the tube, and/or in order to keep the stack in place.

In some embodiments, the tubes are connected to each other via connecting fluid tubes. One of the tubes is connected to an inlet tube and one of the tubes is connected to an outlet tube. In some embodiments faces of the HEFTAP obtained are treated to selectively seal gaps between adjacent plates at peripheral locations intended to be blocked for fluid flow as will be explained in detail later.

Reference is now made to <FIG> depicting a flow chart of a method for selectively sealing gaps between adjacent plates of a plates heat exchanger according to yet another aspect of the invention. A plates heat exchanger comprising at least one face comprising broad and narrow gaps is obtained (<NUM>). The varied gaps are the outcome of edges of plates comprising lateral peripheral protrusions complying with the aforementioned conditions.

Adhesive is applied to at least one of the faces of the plates heat exchanger comprising the plates edges (<NUM>), to obtain a selectively sealed plates heat exchanger (or HEFTAP) at least at one face. The adhesive can be applied by brushing, dipping (into a container containing the adhesive), spraying, injecting, spreading or any other known method in the art. In some embodiments, where the plates are designed to be selectively coalesced by heating or by ultrasonic welding, then heating or ultrasonic welding is performed on the entire face of the plates heat exchanger.

In some embodiments the method further comprises applying an adhesive to more than one face of the HEFTAP (<NUM>).

In some embodiments the method further includes drying the adhesive (<NUM>). In some embodiments the drying comprises air drying. In some embodiments the method further comprises drying the adhesive before an adhesive is applied to another face of the HEFTAP.

In some embodiments the adhesive is selected from at least one of a glue and paint. In some embodiments the adhesive is applied by at least one of dipping, brushing, injecting and spraying. The application of the adhesive can be performed manually or by automated machinery. In some embodiment the sealing is applied without adhesive, such as: heating or ultrasonic welding. In some embodiments the method for selectively sealing is applied on HEFTAPs of the present invention.

In another method for selectively sealing gaps between adjacent plates of a plates heat exchanger, the stack of SFPs is prepared from plates having edges that snap into each other in the sections that block the flow. To this end, the peripheral protrusions 308A-308D of the plates of the SFPs have corresponding recesses on the other plane of the plate so that when the plates are stacked the protrusions of one plate enter the recess of the adjacent plate. In some embodiments the protrusions are designed to make contact along the wall of the corresponding recess when the plates are stacked such that a continuous sealed blocking is formed long the peripheral protrusions/recesses.

In another aspect, not forming part of the claimed invention, the disclosure provides an apparatus enabling a refrigeration process comprising a compressor, an evaporator, an expansion device (e.g. an expansion valve, capillary tube) and an evaporator wherein the condenser is the fin and tube heat exchanger encompassed by a plates heat exchanger (HEFTAP) as described above, wherein the evaporator is positioned downstream the HEFTAP, such that airflow which exits the HEFTAP flows through the evaporator. The apparatus may be a water extraction apparatus (atmospheric water generator), a dryer (e.g. a laundry dryer) or installed in a dehumidification kiln.

In some embodiments the HEFTAP comprises gaps allowing air leaks such that, the mass flow rate through the evaporator is higher than the mass flow rate through the condenser. These leaks are at least at one of (i) at least a portion of the connection area between the fins and the plates upstream the fin, and (ii) at least a portion of the contact line between the blockage protrusions and the adjacent plate.

In yet another aspect, not forming part of the claimed invention, the disclosure provides an apparatus enabling a refrigeration process (a refrigerating apparatus) comprising a compressor, a condenser, an expansion device (e.g. expansion valve, capillary tube) and an evaporator wherein the evaporator is the fin and tube heat exchanger encompassed by a plates heat exchanger as described above, wherein the condenser is positioned downstream the HEFTAP wherein airflow which exits the heat exchanger HEFTAP flows through the condenser. In some embodiments the heat exchanger HEFTAP comprises gaps allowing fluid (e.g. air) leaks such that, the mass flow rate through the condenser is higher than the mass flow rate through the evaporator. These gaps are located at least at one of (i) at least a portion of the connection area between a fin and a plate upstream the fin, and (ii) at least a portion of the contact line between the blockage protrusions and the adjacent plate.

By way of example reference is now made to <FIG> depicting a water extraction apparatus (atmospheric water generator) <NUM> according to an embodiment of the invention. The apparatus <NUM> comprises a container <NUM> having an air inlet <NUM> and air outlet(s) <NUM>, the container <NUM> accommodates a barrier <NUM>, an air filter (optional) <NUM>, a blower <NUM>, a compressor <NUM>, a condenser <NUM>, expansion valve <NUM>, a HEFTAP <NUM> according to an embodiment the present invention as previously described, comprising a fin and tubes heat exchanger acting as an evaporator <NUM>, encompassed by a plates heat exchanger, and a set of refrigerant tubes <NUM>, <NUM>, <NUM> and <NUM>. The person of skill in the art would know to make the necessary conventional adjustments and addition of supplementary elements for the system to work properly. The compressor <NUM> is configured to compress a refrigerant to high temperature dry gas, which may flow through tube <NUM> toward a condenser <NUM>. Within the condenser the refrigerant may be cooled down and become a saturated high temperature liquid. The refrigerant liquid may flow through tube <NUM>, through an expansion valve <NUM>, become a lower temperature mixture of fluid and gas, then through tube <NUM> toward the evaporator <NUM>, wherein the liquid may then evaporate through tube <NUM> back to the inlet of the compressor <NUM> to complete a cycle. The condenser <NUM> emits heat from the refrigerant cycle and the evaporator <NUM> absorbs heat into the refrigerant cycle.

The blower <NUM> which is positioned close to the outlet(s) <NUM> of the container <NUM> is configured to motivate an air flow <NUM> from the air inlet <NUM> through an air filter <NUM> (optional), then the airflow <NUM> may split into two sub-flows 830A and 830B to enter into the HEFTAP <NUM> through the two sets of inlets where multiple counter airflows exchange heat and are stripped from humidity. The air flows 836A and 836B may exit through the two sets of outlets of the HEFTAP <NUM> and combine into airflow <NUM> which passes through the condenser <NUM>, which is positioned downstream the HEFTAP <NUM>. The two air flows 836A and 836B that exit from the two sets of outlets of HEFTAP <NUM> may cool down the condenser <NUM>. <FIG> depicts the two sub-streams (or air flows) 836A and 836B as converging into a single <NUM> stream downstream the condenser <NUM>, however it should be appreciated that the sub-streams 836A and 836B may also converge or begin to converge before flowing through the condenser <NUM>. The flow <NUM> enters the blower <NUM> and exists the apparatus as flow <NUM>. The water extracted from the HEFTAP may be collected into a water reservoir <NUM>. To compensate for leaks of air in the HEFTAP (type I and type II leaks <NUM> and <NUM>, respectively), the blower <NUM> pulls extra air flow to meet the required water extraction yield. Thus, due to the existence of leaks more air mass flow flows through the condenser <NUM> than flows through the evaporator <NUM>. The high flow rate through the condenser contributes to an increase in the heat exchanging rate of the condenser <NUM>, reduces its average temperature and by that increases the COP of the system <NUM> but it also increases the blower power consumption. Therefore, a person of skill in the art may find the balance between keeping some of the leakages and sealing at least a part of them, in order to obtain optimal performance of the system. Thus, in some embodiments, part of the leakages are prevented by having at least part of the aforementioned gaps sealed.

In embodiments of HEFTAPs disclosed in this invention which are involved in treatment or extraction of food products or food grade products including drinks and in particular water, then the materials which come in contact with the treated fluid or the product are made of food grade materials.

It is also noted that in some embodiments, in particular such embodiments which elevated temperatures are used, then the components which are heated during the process should be made of materials which can sustain these temperatures. In some embodiments materials which are stable at <NUM>, in some embodiments <NUM> and in some embodiments <NUM> are used.

Claim 1:
A heat exchanger comprising:
a fins and tubes heat exchanger, comprising a stack of fins (210B), the fins comprising at least one through hole (<NUM>) coupled with a penetrating heat exchanging tube;
a plates heat exchanger comprising a stack of plates (<NUM>), at least two sets of flow inlets and two sets of flow outlets, at least a portion of the plates (<NUM>) each comprising a cutout (<NUM>) and an embossment,
wherein
each one of at least a portion of the fins (210B) of the fins and tubes heat exchanger being at least partially attached to a corresponding plate (<NUM>) of the plates heat exchanger to define a set of a fin and a plate (SFP) wherein the fin is at least partially overlapping the cutout (<NUM>) of the plate (<NUM>), and at least a portion of a peripheral margin (216B) of the fin of the SFP being attached to and overlapping at least <NUM>% of a peripheral margin around the cutout (<NUM>) of the plate (<NUM>) of the SFP such that fluid flowing over either side of the plate comes in contact with the fin (210B), and the other portions of the fin closely fit with the edges of the cutout (<NUM>); and
wherein at least one of: (i) an alternating order of differently embossed plates; and (ii) an alternating orientation of plates in the stack, is adapted to enable one or more of (i) a simultaneous counter fluid flow, (ii) cross fluid flow or (iii) semi counter-cross fluid flow above and below the SFP.