The present invention relates to a heat exchanger, particularly to an electrical heater for a vehicle.

A vehicle generally includes a heater for heating air to be supplied to a passenger compartment. Alternatively, the heater is used to supply heated air to demist or defrost the windscreen. In some cases, the heater is used to supply hot air or hot coolant for cold starting the engine. With the emergence of the electric vehicles, the heater is also applicable for battery thermal management. The heaters can be used for efficient thermal management of the batteries used for powering the electric motor, thereby drastically enhancing the service life of the batteries. The air to be heated is generally passed through a heat exchanger, which includes a heating element such as for example, heat exchange flow pipes through which a heated fluid circulates in case of thermal heater or an electrical resistive heater supplied with current. Particularly, the air to be heated circulates across the heat exchanger and extracts heat from the heating element.

The electrical heater includes a plurality of heating elements arranged with respect to fluid flow passes configured adjacent the heating elements for heat exchange between the fluid flowing through the fluid flow passes and the heating elements. Each heating element includes a tube that receives electrical core therein. Specifically, the tube together with the electrical core forms the heating element. The electrical core is for example, PTC (Positive Temperature Coefficient) resistors. Each tube may have several electrical cores, which may be arranged one after the other in a direction of the tube. Each heating element includes electrodes on both sides for power supply through the heating element. Further, the heating elements include electrically insulating and thermally conductive material layers. The layers being located between one of the electrodes and walls of the tube. In this way, the tube is electrically insulated from the electrodes and the electrical core but thermally in contact with them.

The fluid flow passes are either defined by a housing enclosing the heating elements or by a plurality of modular elements assembled to define the fluid flow passes adjacent to the heating elements. The fluid flow passes are in fluid communication with an inlet and an outlet. The fluid entering the electrical heater through the inlet flows through the fluid flow passes disposed adjacent to the heating elements and in the process extracts heat from the heating elements. The fluid after extracting heat from the heating elements egresses through the outlet. Different flow diverting means, such as for example, deflectors and openings formed on alternative opposite longer walls of the plates configure multiple flow passes between the inlet and the outlet. The flow diverting means are configured with an intension of increasing the fluid flow path between the inlet and the outlet and retaining the fluid adjacent to the heating elements to improve the contact and prolong the time of contact between the fluid and heating elements. Further, in some cases, it is required that the inlet and the outlet be configured on the same side of the electrical heater, in such cases the baffles become inevitable. Although, the arrangement of baffles configuring multiple passes is intended to increase the fluid flow path, retain the fluid adjacent the heating elements, build pressure for homogenous filling of the fluid flow passes with fluid and prevent escape of the fluid from the outlet without undergoing sufficient heat exchange with the heating elements. However, such baffles cause fluid to follow an arch trajectory as the fluid passes the baffle, thereby creating dead zone, i.e. no fluid zone, downstream of the baffle in the fluid flow direction. Further, the electrical heater configured with multiple fluid flow passes fluidly coupled to each other fails to achieve homogeneous fluid filling in all the fluid flow passes. The problem of non- homogeneous fluid filling in the fluid flow passages is because the subsequent fluid flow passes downstream of the baffle in the fluid flow direction depend on homogenous fluid filling in the previous passes upstream of the baffle in the fluid flow direction. More specifically, in case of electrical heater with multiple fluid flow passes to increase the fluid flow path it is difficult to maintain sufficient pressure for the fluid to fill all the fluid flow passes.

For efficient performance of the electrical heater, for example, a high voltage coolant heater, the heat exchange fluid, for example, the coolant is required to be homogeneously distributed in the fluid flow passages. Specifically, the fluid is required to be filled in all the fluid flow passes to achieve sufficient contact between the fluid and the heating elements for efficient heat extraction therefrom. However, conventional electrical heater fails to achieve homogenous distribution of the fluid in the fluid flow passages and fail to achieve filling of all the fluid flow passes, accordingly, the efficiency and performance of the electrical heater is detrimentally impacted. Accordingly, there is a need for an electrical fluid heater configured with multiple fluidly coupled fluid passes that not only increases the fluid flow path but also includes an arrangement to achieve homogeneous fluid distribution and fluid filling in all the fluid flow passes to efficient heat exchange between the fluid and the heating elements. Further, there is a need for an electrical fluid heater that is configured with arrangement for preventing formation of the dead zones inside the electrical heater. Furthermore, there is a need for an electrical fluid heater that exhibits comparatively improved efficiency and performance than the conventional electrical fluid heaters. Further, there is a need for an electrical fluid heater that addresses packaging issues by configuring the inlet and the outlet on same side thereof, while still preventing the problems faced due to use of baffle to achieve U-flow trajectory of the fluid flow.

An object of the present invention is to provide an electrical fluid heater that obviates the problems faced by conventional electrical fluid heaters due to formation of dead zones and inefficiency and low performance caused thereby.

Still another object of the present invention is to provide an electrical fluid heater that ensures homogeneous fluid distribution and fluid filling in all the fluid flow passes to achieve improved efficiency and performance.

Still another object of the present invention is to provide an electrical fluid heater configured with an arrangement to uniformly distribute coolant in the fluid flow passes adjacent to the electric heating elements and configured with features for improving scavenging of the coolant from inside the electrical fluid heater.

In the present description, some elements or parameters may be indexed, such as a first element and a second element. In this case, unless stated otherwise, this indexation is only meant to differentiate and name elements which are similar but not identical. No idea of priority should be inferred from such indexation, as these terms may be switched without betraying the invention. Additionally, this indexation does not imply any order in mounting or use of the elements of the invention.

An electrical fluid heater includes a pair of end plates, a plurality of heating elements and a plurality of intermediate plates. The pair of end plates include a first end plate and a second end plate. The first end plate includes an inlet for ingress of fluid into and an outlet for egress of fluid out of the electrical fluid heater from same side of the electrical fluid heater to cause the fluid to follow a U-turn trajectory between the inlet and the outlet. The second end plate formed with different portions that are in fluid communication with each other. The plurality of intermediate plates are stacked and arranged between the first and the second end plates respectively. The heating elements are sandwiched between the intermediate plates. The adjacent intermediate plates define fluid flow passes adjacent the at least one corresponding heating element to permit heat exchange between the fluid and the at least one corresponding heating element. Each intermediate plate is formed into different sections corresponding to the different portions of the second end plate. The first sections of the intermediate plates defines fluidly coupled first fluid flow passes to receive fluid from the inlet for heat exchange with the heating elements and second sections of the intermediate plates define fluidly coupled second fluid flow passes to deliver fluid to the outlet after heat exchange with the heating elements. The second end plate includes multiple fluid deflecting walls formed on its surface to promote a homogeneous distribution of fluid received in a first portion of the second end plate and homogeneous distribution of the fluid from the first portion to a second portion of the second end plate in the U-turn trajectory between the inlet and the outlet.

Generally, the first end plate includes a first portion corresponding to the first sections of the intermediate plates, and formed with the inlet at the center of the first portion and proximal to a longer wall of the first end plate and a second portion corresponding to the second sections of the intermediate plates and formed with outlet at the center of the second portion and proximal to the longer walls of the first end plate. Each intermediate plate includes a pair of opposite longer walls, a pair of opposite shorter side portions, at least one of guiding pins and corresponding guiding holes and at least one rib. The pair of opposite longer walls is formed with portions corresponding to the first and second sections of the intermediate plate. The portion of the intermediate plate proximal to either one of the opposite longer walls is formed with openings for either one of ingress and egress of fluid from the fluid flow pass defined by the intermediate plate in conjunction with the adjacent intermediate plate. The pair of opposite shorter side portions in conjunction with the pair of opposite longer walls define the periphery of the intermediate plate that defines at least a portion of the fluid flow pass corresponding to the intermediate plate. The at least one rib defines the different sections of the intermediate plate.

Specifically, the guiding pins formed on the intermediate plate engages with corresponding guiding holes of the adjacent intermediate plates to position and assemble the intermediate plate with respect to the adjacent intermediate plate.

Particularly, the openings are formed alternately on the opposite longer walls of each pair of the adjacent intermediate plates to define zig-zag fluid flow path between the inlet and the outlet and permit fluid communication between the fluid flow passes defined by the adjacent intermediate plates.

Specifically, the first portion of the second end plate is configured to collect fluid that has entered the electrical fluid heater through the inlet on the first end plate and percolated through the first fluid flow passes defined by the first sections of the intermediate plates after heat exchange with the corresponding heating elements. The second portion of the second end plate distributes the fluid accumulated there above to the second fluid flow passes defined by the second sections of the intermediate plates.

Particularly, the second end plate includes a first longer wall and a second longer wall respectively disposed opposite to each other and a first shorter side wall and a second shorter side walls disposed opposite to each other, together defining periphery of the second end plate and at least a portion of the fluid flow pass corresponding to the second end plate. The first longer wall of the second end plate is disposed aligned with a corresponding first longer wall of the first end plate proximal to the inlet and the outlet.

Generally, the multiple fluid deflecting walls configured on the second end plate homogeneously distributes the fluid from the first fluid flow passes over the first portion of the second end plate and subsequently the fluid received in the first portion of the second end plate is distributed over the second portion of the second end plate.

Specifically, the fluid deflecting walls include a baffle disposed at the interface between the first portion and the second portion of the second end plate that extends along an axis (A) and orthogonally from the first longer wall.

More specifically, the fluid deflecting walls include a plurality of first curved walls configured on the first portion of the second end plate and extending in a fluid flow direction from a first extreme end thereof to a second extreme end thereof. At least one of the first curved walls extends from the first extreme end in a region proximal to the first longer wall to the second extreme end in a region proximal to an axis (A) of the baffle.

Further, the fluid deflecting walls include a plurality of second curved walls configured on the second portion and extending in a fluid flow direction from a first extreme end thereof to a second extreme end thereof. The first extreme end of at least one of the second curved walls is offset from a first extreme end of the previous second curved wall along the first longer wall. At least one of the second curved walls is having its second extreme end disposed in a region proximal to the first longer wall.

Particularly, at least one pair of adjacent first curved walls directs the fluid received there-between towards at least one gap defined between at least one pair of the adjacent second curved walls.

Further, the first extreme ends of the plurality of first curved walls are disposed on the planes symmetrically to the second extreme ends of the plurality of second curved walls with respect to the axis (A). Furthermore, at least one of the plurality of first curved walls is longer than the second curved walls whose second extreme ends are disposed symmetrically to the first extreme ends of the at least one of the plurality of first curved walls.

In accordance with an embodiment of the present invention, at least one of the plurality of first curved walls has its second extreme end disposed closer from the axis (A) than the first extreme end of the corresponding one of the second curved walls whose second extreme end is disposed symmetrically to the first end of the at least one of the plurality of first curved walls.

Generally, inside corners of the second end plate defined by the second longer wall and the respective shorter sidewalls of the second end plate is a curved profile that directs fluid towards the first curved walls and the second curved walls and from the first curved walls towards the second curved walls.

Other characteristics, details and advantages of the invention can be inferred from the description of the invention hereunder. A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying figures, wherein:

FIG. 1 illustrates an isometric view of an electrical fluid heater in accordance with an embodiment of the present invention;

FIG. 2 illustrates an exploded view of the electrical fluid heater of FIG. 1 ;

FIG. 3 illustrates an isometric view of a first end plate of the electrical fluid heater of FIG. 1 ; FIG. 4 illustrates an isometric view of the heating element in accordance with an embodiment of the present invention;

FIG. 5 illustrates an isometric view of an intermediate plate of a pair of adjacent intermediate plates defining at least a portion of a fluid flow pass;

FIG. 6 illustrates an isometric view of the adjacent intermediate plate of the pair of adjacent intermediate plates, wherein the adjacent intermediate plate in conjunction with the intermediate plate of FIG. 4 defines at least a portion of the fluid flow pass; and

FIG. 7 illustrates a top view of a second end plate configured with multiple fluid deflecting walls formed on its surface.

The present invention envisages an electrical fluid heater, particularly, a high temperature coolant heater, hereinafter, simply referred to as a fluid heater. The fluid heater includes a pair of end plates, a plurality of heating elements and a plurality of intermediate plates. The pair of end plates include a first end plate and a second end plate. The first end plate includes a first portion and a second portion formed with an inlet for ingress of fluid into and an outlet for egress of fluid out of the fluid heater from same side of the fluid heater. The second end plate is formed with different portions that are in fluid communication with each other unlike different portions of the first end plate that are in fluid isolation with each other. Such configuration of the fluid heater causes the fluid to follow a U-turn trajectory between the inlet and the outlet. The plurality of intermediate plates are stacked and arranged between the first and the second end plates respectively. The heating elements are sandwiched between the adjacent intermediate plates. The adjacent intermediate plates define fluid flow passes adjacent the at least one corresponding heating element to permit heat exchange between the fluid and the at least one corresponding heating element. Each intermediate plate is formed into different sections corresponding to the different portions of the second end plate. The first sections of the intermediate plates defines fluidly coupled first fluid flow passes to receive fluid from the inlet for heat exchange with the heating elements and second sections of the intermediate plates define fluidly coupled second fluid flow passes to deliver fluid to the outlet after heat exchange with the heating elements. The second end plate is limited by peripheral walls that define limits of the second end plate and at least a portion of the fluid flow pass corresponding thereto. The second end plate further includes multiple fluid deflecting walls formed on its surface. The fluid deflecting walls promote a homogeneous distribution of fluid received in a first portion of the second end plate and homogeneous distribution of the fluid from the first portion to a second portion of the second end plate to define U-turn trajectory between the inlet and the outlet.

Although, the present invention is described in the forthcoming description and the accompanying drawings with an example of an electrical fluid heater for a vehicle. However, the present invention is also applicable for any heat exchanger for use in vehicular and non-vehicular applications, wherein the heat exchanger includes inlet and outlet on the same side thereof to cause the fluid to follow a U-turn trajectory between the inlet and the outlet. More specifically, the present invention is also applicable for tubular fluid heat exchanger apart from the electrical fluid heaters. The tubular heat exchanger includes tubular elements configuring flow of first heat exchange fluid there through and a second heat exchange fluid flows through fluidly coupled first and second fluid flow passes adjacent the tubular elements carrying the first fluid to undergo heat exchange with the first fluid. Particularly, the present invention is applicable where it is required that fluid is homogeneously filled in the first and second fluid passes and formation of dead zones in either of the first pass and the second pass is to be avoided to achieve improved heat exchange for enhancing efficiency and performance of the tubular heat exchanger.

FIG. 1 illustrates an isometric view of an electric fluid heater 100, hereinafter referred to as fluid heater 100, in accordance with an embodiment of the present invention. The fluid heater 100 includes a pair of end plates 10 and 20, a plurality of heating elements 30 and a plurality of intermediate plates 40, wherein each intermediate plate 40 is formed of different sections 40a and 40b. FIG. 2 illustrates an exploded view of the fluid heater 100 and the sequence in which the different elements of the fluid heater 100 are arranged and assembled with respect to each other. The pair of end plates 10 and 20 include a first end plate 10 and a second end plate 20. Referring to the FIG. 3, the first end plate 10 is defined by the opposite longer walls 12 and 14 and the pair of opposite shorter walls 16 and 18. The opposite longer walls 12 and 14 are also referred to as first and second longer walls 12 and 14. The opposite shorter walls 16 and 18 are also referred to as first and second shorter walls 16 and 18. The opposite longer walls 12 and 14 and the opposite shorter walls 16 and 18 define the periphery of the first end plate 10 and at least a portion of the fluid flow passes corresponding to the first end plate 10. The first end plate 10 includes an inlet 12a for ingress of fluid into and an outlet 12b for egress of fluid out of the fluid heater 100 from same side of the fluid heater 100 to achieve certain advantages. For example, configuring the inlet 12a and the outlet 12b on the same side of the fluid heater 100 provides compact configuration to the fluid heater 100 and addresses packaging issues. Further, such configuration also addresses routing issues associated with routing of inlet and outlet conduits connected to the inlet 12a and the outlet 12b for supplying and delivering out fluid from the fluid heater 100. The second end plate 20 fluidly couples the first and the second fluid flow passes formed adjacent the heating elements 30 and in fluid communication with the inlet 12a and the outlet 12b respectively. Such configuration of the fluid heater 100 with end plates 10 and 20, the end plate 20 formed with fluidly coupled first and second portions 20a and 20b, the inlet 12a and the outlet 12b on same side causes the fluid to follow a U-turn trajectory between the inlet 12a and the outlet 12b. Specifically, the first end plate includes a first portion 10a and a second portion 10b, wherein a groove 19 separates the first portion 10a from the second portion 10b. The first portion 10a and the second portion 10b are raised portion that inherently form the groove at the interface between first portion 10a and the second portion 10b. The cross section of the first portion 10a is increasing from the inlet 12a towards the first fluid flow passes defined by the first sections 40a. Further as illustrated in FIG. 1 - FIG. 3, the inlet 12a is disposed at the center of the first portion 10a and proximal to the longer walls 12 of the first end plate 10. Such strategic placement of the inlet ensures even distribution of the coolant to the portion of the fluid flow passes defined by the first sections 40a. Similarly, the second portion 10b corresponding to the second sections 40b of the intermediate plates 40 and is converging from the second sections 40b to the outlet 12b in the fluid flow direction. Specifically, the cross section of the second portion 10b is decreasing from the second fluid flow passes defined by the second sections 40b towards the outlet 12b. Further, again referring to the FIG. 1 - FIG. 3, the outlet 12b is also disposed at the center of the second portion 10b and proximal to the longer walls 12 of the first end plate 10. In accordance with another embodiment of the present invention, the outlet 12b is disposed at the corner of the first end plate 10 defined at the intersection of the first longer wall 12 and the first shorter wall 16. Specifically, the outlet 12b is farthest from the groove 19. Such strategic placement of the outlet 12b ensures that the portion of the fluid flow passes defined by the second sections 40b of the intermediate plates is filled before the fluid egresses through the outlet 12b. More specifically, such strategic placement of the outlet 12b ensures even distribution of the coolant in the fluid flow passes defined by the second sections 40b before egressing through the outlet 12b. Such configuration of the outlet avoids trapping air in the area beneath the second portion and the fluid flow passes defined by the second sections 40b by scavenging the fluid evenly underneath the second portion 10b of the first end plate 10. In another embodiment, the outlet 12b can be disposed horizontally instead of being disposed vertically the to reduce back-pressure and improve flow path. However, the present invention is not limited to any particular configuration of the first end plate 10 with the inlet 12a and the outlet 12b in any particular position. The inlet and the outlet can be positioned on the first and the second potions so as to avoid air trapping by scavenging the fluid evenly underneath the first and second portions 10a and 10b respectively based on multiple fluid deflecting walls 50 formed on surface of the second end plate 20. Similar to the first end plate 10, the second end plate 20 is formed with different portions 20a and 20b, refer FIG. 7 for details. The first portion 20a and the second portion 20b of the second end plate 20 is corresponding to the first sections 40a and the second sections 40b of the intermediate plates 40 and the first portion 10a and the second portion 10b of the first end plate 10. However, the first and the second portions 20a and 20b of the second end plates 20 are in fluid communication with each other unlike the first and second portions 10a and 10b of the first end plate 10.

The heating elements 30 are sandwiched between the intermediate plates 40. Referring to FIG. 4, each heating element 30 includes a tube 32 that receives electrical core 34 therein. The tube 32 together with the electrical core 34 forms the heating element 30. The electrical core 34, is for example, PTC (Positive Temperature Coefficient) resistors. Each tube 32 may have several electrical cores 34, which may be arranged one after the other in a direction of the tube 32. Each heating element 30 includes electrodes 36 on both sides for power supply through the heating element 30. Further, the heating elements 30 includes electrically insulating and thermally conductive material layers 38. The layers 38 being located between one of the electrodes 36 and walls 32a and 32b of the tube 32. In this way, the tube 32 is electrically insulated from the electrodes 36 and the electrical core 34 but thermally in contact with them.

The plurality of intermediate plates 40 are stacked and arranged between the first and the second end plates 10 and 20 respectively. The adjacent intermediate plates 40 define fluid flow passes adjacent the at least one corresponding heating element 30 to permit heat exchange between the at least one heating element 30 and the fluid flowing through the corresponding fluid flow passages defined by the adjacent intermediate plates 40. Referring to FIG. 5 and FIG. 6, each intermediate plate 40 is formed into different sections 40a and 40b corresponding to the different portions 20a and 20b of the second end plate 20 and the different portions 10a and 10b of the first end plate 10. The first sections 40a of the intermediate plates 40 defines fluidly coupled first fluid flow passes. In the assembled configuration of the intermediate plates 40, the first fluid flow passes receive fluid distributed thereto by the first portion 10a of the first end plate 10 from the inlet 12a for heat exchange with at least a portion of the heating elements 30 sandwiched between the intermediate plates 40. Also, the second sections 40b of the intermediate plates 40 define fluidly coupled second fluid flow passes. The second flow passes deliver fluid to the second portion 10b of the first end plate 10 for egress through the outlet 12b after heat exchange with the heating elements 30 in the assembled configuration of the intermediate plates. The intermediate plates 40 are positioned and assembled to each other by using first positioning elements 42b, 44b and corresponding second positioning elements 42c, 44c formed on the adjacent intermediate plates 40. More specifically, the guiding

FIG. 5 and FIG. 6 illustrates isometric views of the intermediate plates 40. FIG. 4 illustrates an isometric view of the intermediate plate 40 of a pair of adjacent intermediate plates defining at least a portion of a fluid flow pass. FIG. 5 illustrates an isometric view of the adjacent intermediate plate of the pair of adjacent intermediate plates, wherein the adjacent intermediate plate in conjunction with the other intermediate plate of the pair of adjacent intermediate plates arranged in axial direction with respect to each other defines at least a portion of the fluid flow pass. Each intermediate plate 40 includes a pair of opposite longer walls 42 and 44, hereinafter referred to as the first and the second longer walls 42 and 44 respectively, a pair of opposite shorter side portions 46 and 48, hereinafter, referred to as first and second shorter side portions 46 and 48 respectively. The pair of opposite shorter side portions 46 and 48 in conjunction with the pair of opposite longer walls 42 and 44 define the periphery of the intermediate plate 40 that defines at least a portion of the fluid flow pass defined by the adjacent intermediate plates 40. Each longer wall 42, 44 of the pair of opposite longer walls 42 and 44 is formed with separate portions corresponding to the first and second sections 40a and 40b of the intermediate plate 40.

The portion of the intermediate plate 40 proximal to either one of the opposite longer walls 42 and 44 is formed with openings or slots 42a, 44a for either one of ingress and egress of fluid from the fluid flow pass defined by the intermediate plate in conjunction with the adjacent intermediate plate. The openings or slots 42a, 44a are formed alternately on the opposite longer walls 42, 44 of each pair of the adjacent intermediate plates to define zig-zag fluid flow path between the inlet 12a and the outlet 12b and permit fluid communication between the fluid flow passes defined by the adjacent intermediate plates. The zig-zag fluid flow path between the inlet 12a and the outlet 12b increases the length of the fluid flow path and accordingly enhances the contact area and contact time between the fluid flowing through the fluid flow passes and the heating element 30, thereby improving the efficiency and performance of the fluid heater 100. In accordance with an embodiment, if the openings or slots 44a are formed on the adjacent intermediate plates 40 at portions thereof proximal to second longer side wall 44, then, the corresponding openings or slots 42a are formed on the subsequent adjacent intermediate plates 40 at portions thereof proximal to first longer side wall 42 that is opposite to the second longer side 44. In a preferred embodiment of the present invention, each pair of the adjacent intermediate plates 40 include slots 42a, 44a instead of the openings formed alternately on the opposite longer walls 42, 44 thereof. However, the present invention is not limited to any particular number, placement and configuration of the openings I slots formed on the portions of the adjacent intermediate plates 40 proximal to either one of the opposite longer walls 42 and 44 as far as the slots I openings define zig-zag fluid flow path between the inlet 12a and the outlet 12b and permit fluid communication between the fluid flow passes defined by the adjacent intermediate plates Each intermediate plate 40 includes at least one of first positioning elements 42b and 44b in the form of guiding pins 42b and 44b and corresponding second positioning elements 42a and 44c in the form of guiding holes 42c and 44c. The guiding pins 42b and 44b formed on the intermediate plate 40 engages with the corresponding guiding holes 42c and 44c of the adjacent intermediate plate 40 to position and assemble the intermediate plate with respect to the adjacent intermediate plate. Referring to the FIG. 5, there are two guiding pins 42b along the portion of the intermediate plate 40 proximal to the first longer side wall 42, each guiding pin 42b disposed on the respective portions of the intermediate plate corresponding to the two sections 40a and 40b of the intermediate plate 40. Further, there are two guiding pins 44b along the portion of the intermediate plate 40 proximal to the second longer side wall 44, each guiding pin 44b disposed on the respective portions of the intermediate plate 40 corresponding to the two sections 40a and 40b of the intermediate plate 40. Referring to the FIG. 6, there are two guiding holes 42c along the portion of the adjacent intermediate plate 40 proximal to the first longer side wall 42, each guiding hole 42c disposed on the respective portions of the adjacent intermediate plate 40 corresponding to the two sections 40a and 40b of the intermediate plate 40. Further, there are two guiding holes 44c along the portion of the intermediate plate 40 proximal to the second longer side wall 44 each guiding hole 44c disposed on the respective portions of the adjacent intermediate plate 40 corresponding to the two sections 40a and 40b of the adjacent intermediate plate 40. However, the present invention is not limited to any particular number, placement and configuration of the positioning and assembling means for assembling together the intermediate plates in aligned manner such that the opening or slots 42a, 44a formed on the adjacent pair of intermediate plates 40 are aligned with respect to each other to define zig-zag fluid flow path between the inlet 12a and the outlet 12b and permit fluid communication between the fluid flow passes defined by the adjacent intermediate plates.

Further, each intermediate plate 40 includes at least one rib 49. The at least one rib 49 defines the different sections of the intermediate plate 40. The ribs 49 of the adjacent intermediate plates 40 acts as poke - yoke feature and facilitates in correct assembly between the adjacent intermediate plates 40. Referring to the FIG. 7 of the accompanying drawings, the second end plate 20 includes multiple fluid deflecting walls 50 formed on the surface thereof. Particularly, the multiple deflecting walls 50 configured on the second end plate 20 homogeneously distributes the fluid from the first fluid flow passes over the first portion 20a of the second end plate 20 and subsequently the fluid from the first portion 20a over the second portion 20b of the second end plate. More particularly, the first portion 20a of the second end plate 20 is configured with fluid deflecting walls 50 to collect fluid that has percolated through the first fluid flow passes defined by the first sections 40a of the intermediate plates 40 after heat exchange with the corresponding heating elements 30 sandwiched between the adjacent intermediate plates 40. The second portion 20b of the second end plate 20 distributes the fluid accumulated there above to the second fluid flow passes defined by the second sections 40b of the intermediate plates 40. The second end plate 20 includes a first longer wall 22 and a second longer wall 24 respectively disposed opposite to each other and a first shorter side wall 26 and a second shorter side wall 28 disposed opposite to each other. The pair of opposite first and second longer walls 22 and 24 along with the pair of opposite shorter side walls 26 and 28 together define periphery of the second end plate 20 and at least a portion of the fluid flow pass corresponding to the second end plate 20. The first longer wall 22 of the second end plate 20 is disposed aligned with a corresponding first longer wall 12 of the first end plate 10 proximal to the inlet 12a and the outlet 12b and opposite to a second longer wall 14 of the first end plate 10. The inside corners of the second end plate 20 defined by the second longer wall 24 and the respective first and second shorter side walls 26 and 28 of the second end plate 20 is a curved profile that directs fluid towards first curved walls 54 and second curved walls 56 formed on surface of first and second portions 20a and 20b of the second end wall 20 and from the first curved walls 54 towards the second curved walls 56.

Referring to the FIG. 7, the fluid deflecting walls 50 includes a baffle 52 disposed at the interface between the first portion 20a and the second portion 20b of the second end plate 20. The baffle 52 extends along an axis (A) and orthogonally from the first longer wall 22. Further, the fluid deflecting walls 50 includes the first curved walls 54 configured on the first portion 20a of the second end plate 20 and extending in a fluid flow direction from a first extreme end 54a thereof to a second extreme end 54b thereof. More specifically, at least one of the first curved walls 54 extends from the first extreme end 54a disposed in a region proximal to the first longer wall 22 to the second extreme end 54b disposed in a region proximal to an axis ‘A” of the baffle 52. The first extreme ends 54a of the first curved walls 54 are so disposed with respect to the first longer wall 22 to receive and direct the fluid received from the first fluid flow passes defined by the first sections 40a of the intermediate plates 40 to the gaps between the adjacent first curved walls 54. At least one of the first curved walls 54 follows a curved profile with the vertex of the curved profile being complementary to and aligned with but spaced from the curved profile formed at the first inside corner of the second end plate 20 defined by the second longer wall 24 and the second shorter sidewall 28. Further, the fluid deflecting walls 50 includes a plurality of second curved walls 56 configured on the second portion 20b of the second end plate 20 and extending in a fluid flow direction from a first extreme end 56a thereof to a second extreme end 56b thereof. The first extreme end 56a of at least one of the second curved walls 56 is offset from a first extreme end 56a of the previous second curved wall 56 along the first longer wall 22. The first extreme ends 56a of the second curved walls 56 receive and direct the fluid directed thereto by the first curved walls 54 towards the gaps between the adjacent second curved walls 56. At least one of the second curved walls 56 is having its second extreme end 56b disposed in a region proximal to the first longer wall 22. At least one of the second curved walls 56 follows a curved profile with the vertex of the curved profile being complementary to and aligned with but spaced from the curved profile formed at the second inside corner of the second end plate 20 defined by the second longer wall 24 and the first shorter side wall 26.

Particularly, at least one pair of adjacent first curved walls 54 directs the fluid received there-between towards at least one gap defined between at least one pair of the adjacent second curved walls 56. Further, the first extreme ends 54a of the plurality of first curved walls 54 are disposed on the planes symmetrically to the second extreme end 56b of the plurality of second curved walls 56 with respect to the axis “A”. Furthermore, at least one of the plurality of first curved walls 54 is longer than the second curved walls 56 whose second extreme end 56b is disposed symmetrically to the first end 54a of the at least one of the plurality of first curved walls 54. In accordance with an embodiment of the present invention, at least one of the plurality of first curved walls 54 has its second end thereof 54b disposed closer to the axis (A) than the first end 56a of the corresponding one of the second curved walls 56 whose second extreme ends 56b are disposed symmetrically to the first ends 54a of the at least one of the plurality of first curved walls 54. The baffle 52 terminates at before the first extreme ends 54a of the first curved walls 54 and the second extreme end 56b of the second curved walls 56.

In any case, the invention cannot and should not be limited to the embodiments specifically described in this document, as other embodiments might exist. The invention shall spread to any equivalent means and any technically operating combination of means.