[0001] The present invention generally relates to an electric fluid heater, more particularly
to an electric fluid heater for vehicles.
[0002] 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 fluid 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 fluid to be heated circulates across the heat exchanger and extracts heat from
the heating element.
[0003] The electrical heater includes a plurality of heating elements arranged with respect
to fluid flow passes configured adjacent the heating elements 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. Each tube may have several electrical
cores, which may be arranged one after the other in a direction of the tube. The electrical
core may include a resistive element. 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. The material 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.
[0004] Generally, the housing enclosing the heating elements placed between a pair heat
exchanger plates of the heat exchanger having a plate stack. The plate stack are provided
with an inlet port and an outlet port. The ports are in fluid communication with the
fluid passage formed through the plate stack. The plates are arranged such that a
fluid flow passage is formed around each pair of heat exchanger plates. The fluid
entering the electrical heater flows from the inlet, and then passes through the fluid
flow passage formed around each pair of plates. Simultaneously, the fluid extracts
heat from the heating elements and egresses through the outlet.
[0005] However, this arrangement has a potential risk of formation of air pockets between
the housing of the heating element and the plates, and a risk of degradation of heating
element because of the insulation material filled between the heating element and
the housing. Further, in this arrangement, heat transfer need to take place through
two layer of plates, which includes the housing of the heating element and the heat
transfer plate above the housing of the heating element. Thus, this arrangement lacks
to provide efficient heat transfer between the heating element and the fluid flowing
around the heat transfer plates. Consequently, overheating at any spot in heat exchanger
will become difficult to detect as the heater lacks to provide efficient heat transfer.
[0006] Accordingly, there is a need for an electric fluid heater that optimizes thermal
efficiency, while addressing the aforementioned issues.
[0007] 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.
[0008] In view of forgoing, the present invention discloses an electric fluid heater comprising
a plate stack comprising a first end plate, a second end plate, an intermediate plate
stack comprising a plurality of intermediate plates arranged between the first end
plate and the second end plate. The second end plate formed with different portions
that are in fluid communication with each other. Each intermediate plate is divided
into different sections, respectively, corresponding to the different portions of
the second end plate. The first end plate is provided with an inlet port in fluid
communication with a first fluid path formed through the section of the intermediate
plates and an outlet port in fluid communication with a second fluid flow path formed
through the section of the intermediate plates. The inlet port and the outlet port
provided in a same side of the heater adapted to cause the fluid to follow a U-turn
trajectory between the inlet port and the outlet port.
[0009] Further, the intermediate plate stack is arranged in pairs of plate. Each pair includes
a first intermediate plate and a second intermediate plate. The first intermediate
plate being joined to the second intermediate plate to form an interspace therebetween
to accommodate at least one heating module without welding thereto. In one embodiment,
the interspace is a hollow space. In another embodiment, the interspace is a tubular
space.
[0010] Further, each intermediate plate comprises a first edge portion and a second edge
portion opposite to that of the first edge portion. The first intermediate plate comprises
a depression along a length of the first and second edge portions thereof and the
second intermediate plate comprises an elevation complementary to the depression along
a length of the first and second edge portions thereof.
[0011] The depression of the first intermediate plate brought in contact with the elevation
of the second intermediate plate and brazed at the contacting portions defined by
the elevation and depression of the each intermediate plate pair, thereby forming
the interspace therebetween. The depression of the first intermediate plate divided
into a first section corresponding to the first section of the plate stack and a second
section corresponding to the second section of the plate stack. The elevation of the
second intermediate plate divided into a first section corresponding to the first
section of the plate stack and a second section corresponding to the second section
of the plate stack.
[0012] In one example, the depression has at least one of a rectangular shaped cross section
and a square shaped cross section. In another example, the elevation has at least
one of a rectangular shaped cross section and a square shaped cross section.
[0013] The present invention further discloses a method for manufacturing the electric fluid
heater. The method comprising steps of: attaching the first intermediate plate to
their adjacent second intermediate plate to form the interspace therebetween, and
filling at least one heating module within the interspace without welding thereto.
In another embodiment, the heating module may be filled within the interspace using
thermally conductive adhesive material. The adhesive material achieves a homogeneous
contact between the plates the entire heating element surface, thereby avoiding hotspots.
[0014] The method further comprises a step of welding a heater housing at each interspace
of the plate stack, and accommodating at least one heating element within the heater
housing and filling thermally conductive material between the heater housing and the
heating element.
[0015] In another embodiment, the electric fluid heater comprises a plate stack having a
plurality of intermediate plates. The plate stack provided with an inlet port and
an outlet port. The inlet port and the outlet port in fluid communication with a fluid
passage formed through the plate stack. The plate stack is arranged in pairs of intermediate
plates. Each pair includes a first intermediate plate and a second intermediate plate.
The first intermediate plate being joined to the second intermediate plate to form
an interspace therebetween to accommodate at least one heating module without welding
thereto.
[0016] 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 a perspective view of a first end plate of FIG. 1;
FIG. 4 illustrates a perspective view of a second end plate of FIG. 1;
FIG. 5 illustrates a perspective view of a pair of intermediate plates forming an
interspace of FIG. 1;
FIG. 6 illustrates a perspective view of a first intermediate plate of FIG. 1;
FIG. 7 illustrates a perspective view of a second intermediate plate of FIG. 1, and
FIG. 8 illustrates a perspective view of a heating module of FIG. 1.
[0017] It must be noted that the figures disclose the invention in a detailed enough way
to be implemented, said figures helping to better define the invention if needs be.
The invention should however not be limited to the embodiment disclosed in the description.
[0018] The present invention discloses an electric fluid heater comprising a plate stack
comprising a first end plate, a second end plate, an intermediate plate stack comprising
a plurality of intermediate plates arranged between the first end plate and the second
end plate. The second end plate formed with different portions that are in fluid communication
with each other. Each intermediate plate is divided into different sections, respectively,
corresponding to the different portions of the second end plate. The first end plate
is provided with an inlet port in fluid communication with a first fluid path formed
through the section of the intermediate plates and an outlet port in fluid communication
with a second fluid flow path formed through the section of the intermediate plates.
The inlet port and the outlet port provided in a same side of the heater adapted to
cause the fluid to follow a U-turn trajectory between the inlet port and the outlet
port.
[0019] Further, the intermediate plate stack is arranged in pairs of plate. Each pair includes
a first intermediate plate and a second intermediate plate. The first intermediate
plate being joined to the second intermediate plate to form an interspace therebetween
to accommodate at least one heating module without welding thereto. This arrangement
address the risk of degradation of heating elements and formation of air pockets.
Further, this arrangement of the heating module in contact with the intermediate plate
provides efficient heat transfer between the heating module and the fluid.
[0020] 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 comprises a plate stack 102 having a plurality of intermediate
plates. The plate stack 102 includes a pair of end plates 104 and 108, a plurality
of heating modules 122 and a plurality of intermediate plates 112, wherein each intermediate
plate 112 is formed of different sections 112A and 112B. 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 104 and 108 include a first end plate 104 and a second end plate 108.
[0021] Referring to FIG. 1 to FIG. 3, the plurality of intermediate plates 112 are arranged
in pairs of intermediate plate 114, 116. Each pair 114, 116 includes a first heat
intermediate plate 114 and a second intermediate plate 116. The first intermediate
plate 114 being joined to the second intermediate plate 116 to form an interspace
136 therebetween. A fluid flow path or fluid flow passes is defined adjacent to a
pair of intermediate plates 114, 116 and a heating module 122. Each intermediate plate
112 is formed into different sections 112A, 112B corresponding to the different portions
106A, 106B of the first end plate 104 and the different portions 110A, 110B of the
second end plate 108. The first sections 112A of the intermediate plates 112 defines
fluidly coupled first fluid flow passes. The second sections 112B of intermediate
plates 112 defines fluidly coupled second fluid flow passes. The first fluid flow
passes are also referred as first fluid path and the second fluid flow passes are
also referred as second fluid path throughout this document.
[0022] Referring to FIG. 3, the first end plate 104 is defined by the opposite longer walls
124 and 126 and the pair of opposite shorter walls 128 and 130. The opposite longer
walls 124 and 126 are also referred to as first and second longer walls 124 and 126.
The opposite shorter walls 128 and 130 are also referred to as first and second shorter
walls 128 and 130. The opposite longer walls 124 and 126 and the opposite shorter
walls 128 and 130 define the periphery of the first end plate 104 and at least a portion
of the fluid flow passes corresponding to the first end plate 104. The first end plate
104 includes an inlet 118 for ingress of fluid into and an outlet 120 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 118 and the outlet 120 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
118 and the outlet 120 for supplying and delivering out fluid from the fluid heater
100. The second end plate 108 fluidly couples the first and the second fluid flow
passes formed around adjacent the heating modules 122 and in fluid communication with
the inlet 118 and the outlet 120, respectively.
[0023] The first end plate 104 includes a first portion 106A and a second portion 106B,
wherein a groove 132 separates the first portion 106A from the second portion 106B.
The first portion 106A and the second portion 106B are raised portion that inherently
form the groove 132 at the interface between first portion 106A and the second portion
106B. The cross section of the first portion 106A is increasing from the inlet 118
towards the first fluid flow passes defined by the first sections 112A.
[0024] Referring to FIG. 4, the second end plate 108 includes a first and second longer
wall 176, 178, and a first and second shorter wall 180, 182. The first and second
longer wall 176, 178, and the first and second shorter wall 180, 182 defines the periphery
of the end plate 108. The second end plate 108 formed with fluidly coupled first and
second portions 110A and 110B. The inlet 118 and the outlet 120 on same side causes
the fluid to follow a U-turn trajectory between the inlet 118 and the outlet 120.
[0025] Further as illustrated in FIG. 1 - FIG. 3, the inlet 118 is disposed at the centre
of the first portion 106A and proximal to the longer walls 124 of the first end plate
104. Such strategic placement of the inlet 118 ensures even distribution of the coolant
to the portion of the fluid flow passes defined by the first sections 112A. Similarly,
the second portion 106B corresponding to the second sections 112B of the intermediate
plates 112 and is converging from the second sections 112B to the outlet 120 in the
fluid flow direction. Specifically, the cross section of the second portion 106B is
decreasing from the second fluid flow passes defined by the second sections 112B towards
the outlet 120.
[0026] Further, again referring to the FIG. 1 - FIG. 3, the outlet 120 is also disposed
at the centre of the second portion 106B and proximal to the longer walls 124 of the
first end plate 104. In accordance with another embodiment of the present invention,
the outlet 120 is disposed at the corner of the first end plate 104 defined at the
intersection of the first longer wall 124 and the first shorter wall 128. Specifically,
the outlet 120 is farthest from the groove 124. Such strategic placement of the outlet
120 ensures that the portion of the fluid flow passes defined by the second sections
112B of the intermediate plates 112 is filled before the fluid egresses through the
outlet 120. More specifically, such strategic placement of the outlet 120 ensures
even distribution of the coolant in the fluid flow passes defined by the second sections
112B before egressing through the outlet 120. Such configuration of the outlet 120
avoids trapping air in the area beneath the second portion and the fluid flow passes
defined by the second sections 112B by scavenging the fluid evenly underneath the
second portion 106B of the first end plate 104. In another embodiment, the outlet
120 can be disposed horizontally instead of being disposed vertically to reduce back-pressure
and improve flow path.
[0027] However, the present invention is not limited to any particular configuration of
the first end plate 102 with the inlet 118 and the outlet 120 in any particular position.
The inlet and the outlet can be positioned on the first and the second portions so
as to avoid air trapping by scavenging the fluid evenly underneath the first and second
portions 106A and 106B respectively based on multiple fluid deflecting walls 134,
shown in FIG.4, formed on surface of the second end plate 108. The first portion 110A
and the second portion 110B of the second end plate 108 is corresponding to the first
sections 112A and the second sections 112B of the intermediate plates 112 and the
first portion 106A and the second portion 106B of the first end plate 104. However,
the first and the second portions 110A and 110B of the second end plates 108 are in
fluid communication with each other unlike the first and second portions 106A and
106B of the first end plate 104.
[0028] Referring to FIG. 1 to 3, in the assembled configuration of the intermediate plates
112, the first fluid flow passes receive a heat exchange fluid distributed thereto
by the first portion 106A of the first end plate 104 from the inlet 118 for heat exchange
with at least a portion of the heating module 122 sandwiched between the intermediate
plates 112. The second end plate 108 fluidly couples the first fluid passes to the
second fluid passes. The second flow passes deliver fluid to the second portion 106B
of the first end plate 104 for egress through the outlet 120 after heat exchange with
the heating module 122 in the assembled configuration of the intermediate plates 112.
[0029] Referring to FIG. 5, each intermediate plate 112 includes a first edge portion 140A
and a second edge portion 140B opposite to that of the first edge portion 140A. Each
intermediate plate 112 further includes a first side portion 142A and a second side
portion 142B opposite to that of the first side portion 142A. The first edge portion
140A and the second edge portion 140B are the longer sidewalls of the intermediate
plate 112. The first side portion 142A and the second side portion 142B are the shorter
sidewalls of the intermediate plate 112. The longer sidewalls and the shorter sidewalls
defines the periphery of the intermediate plate 112 that defines at least a portion
of the fluid flow passes defined by the adjacent intermediate plates 112.
[0030] The first intermediate plate 114 comprises a depression 146 along a length of the
first and second edge portions 140A, 140B. The second intermediate plate 116 comprises
an elevation 148 complementary to the depression 146 along a length of the first and
second edge portions 140A, 140B thereof.
[0031] The depression 146 of the first intermediate plate 114 brought in contact with the
elevation 148 of the second intermediate plate 116 and joined at the contacting portions
defined by the elevation 148 and depression 146 of each pair of intermediate plate
plates 112 to form an interspace 136 therebetween. At least one heating module 122
is accommodated at the interspace 136 of each pair of intermediate plates 112. In
one embodiment, the heating module 122 may include at least two sections, which corresponds
to the different sections 112A, 112B of the intermediate plate 112. The interspace
136 comprises a profile complementary to the profile of the heating module 122. The
heating module 122 is slid into the interspace 136, which accommodates the heating
module 122 therein without welding. In one embodiment, the heating module 122 is slid
into the interspace 136 and thermally conductive type adhesive material may be filled
between the heating module 122 and the plates 112. The adhesive material achieves
a homogeneous contact between the plates 112 the entire heating module surface, thereby
avoiding hotspots. In one embodiment, the depression 146 has at least one of a rectangular
shaped cross section and a square shaped cross section. In one embodiment, the elevation
148 has at least one of a rectangular shaped cross section and a square shaped cross
section. In one embodiment, the interspace 136 is a hollow space. In another embodiment,
the interspace 136 is a tubular space.
[0032] Referring to FIG. 8, in an example, the heating module 122 comprises a tube 166 that
receives an electrical core or heating element 164 therein. The electrical core 164,
is for example, PTC (Positive Temperature Coefficient) resistors. Each tube 166 may
have several electrical cores 164, which may be arranged one after the other in a
direction of the tube 166. Each heating module 122 includes electrodes 168 on both
sides for power supply through the heating module 122. Alternatively, the electrodes
168 may be on the same side of the heating module 122, which may reduce the number
of components and packaging size. Further, the heating module 122 includes electrically
insulating and thermally conductive material 170. The material 170 being located between
one of the electrodes 168 and walls 172 of the tube 166. In this way, the tube 166
is electrically insulated from the electrodes 168 and the electrical core 164 but
thermally in contact with them.
[0033] Referring to FIG. 6, the depression 146 of the first intermediate plate 114 is divided
into a first section 150A corresponding to the first section 112A of the intermediate
plate 112 and a second section 150B corresponding to the second section 112B of the
intermediate plate 112. Referring to FIG. 7, the elevation 148 of the second intermediate
plate 116 is divided into a first section 152A corresponding to the first section
112A of the intermediate plate 112 and a second section 152B corresponding to the
second section 112B of the intermediate plate 112. The first edge portion 140A and
the second edge portion 140B of the intermediate plates 112 are formed with slots
or openings 154, 156 for either one of ingress and egress of fluid from the fluid
pass defined by the adjacent pair of intermediate plates 112.
[0034] The openings or slots 154, 156 are formed alternately on the opposite longer walls
or edge portions 140A, 140B of each pair of the adjacent intermediate plates 112 to
define zig-zag fluid flow path between the inlet 118 and the outlet 120 and permit
fluid communication between the fluid flow passes defined by the adjacent intermediate
plates 112. The zig-zag fluid flow path between the inlet 118 and the outlet 120 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
122, thereby improving the efficiency and performance of the fluid heater 100
[0035] In accordance with an embodiment, if the openings or slots 154 are formed on the
first intermediate plates 114 at portions thereof proximal to the edge portions 140A,
140B, then, the corresponding openings or slots 156 are formed on the subsequent adjacent
intermediate plates 112 or the second intermediate plate 116 at edge portions 140A,
140B.
[0036] Referring to FIG. 6 and FIG. 7, each intermediate plate 112, specifically, the first
intermediate plate 114 includes at least one of first positioning elements 158A, 158B
in the form of guiding pins 158A, 158B and corresponding second positioning elements
160A, 160B in the form of guiding holes 160A, 160B. The guiding pins 158A, 158B formed
on the first intermediate plate 146 engages with the corresponding guiding holes 160A,
160B of the adjacent intermediate plate 116 to position and assemble the intermediate
plate 112 with respect to the adjacent intermediate plate112. Referring to the FIG.
5, there are two guiding pins 158A along the portion of the first intermediate plate
114 proximal to the first edge portion 140A. Further, there are two guiding pins 158B
along the portion of the second intermediate plate 116 proximal to the second edge
portion 140B. Each guiding pin 158A, 158B disposed on the respective portions of the
intermediate plate 114 corresponding to the two sections 112A, 112B of the intermediate
plate 114.
[0037] Referring to the FIG. 7, there are two guiding holes 160A along the portion of the
second intermediate plate 116 proximal to the first edge portion 140A, each guiding
hole 160A disposed on the respective portions of the second intermediate plate 116
corresponding to the two sections 112A, 112B of the intermediate plate 116. Further,
there are two guiding holes 160B along the portion of the intermediate plate 116 proximal
to the second edge portion 140B. Each guiding hole 160B disposed on the respective
portions of the second intermediate plate 116 corresponding to the two sections 112A,
112B of the intermediate plate 116.
[0038] However, the present invention is not limited to any particular number, placement
and configuration of the openings / slots formed on the edge portions 140A, 140B of
the adjacent intermediate plates 112 as far as the slots / openings define zig-zag
fluid flow path between the inlet 118 and the outlet 120 and permit fluid communication
between the fluid flow passes defined by the adjacent intermediate plates 112. Further,
each intermediate plate 112 includes at least one rib 162. The at least one rib 162
defines the different sections 112A, 112B of the intermediate plate 112. The ribs
162 of the adjacent intermediate plates 112 acts as poke - yoke feature and facilitates
in correct assembly between the adjacent intermediate plates 112.
[0039] The present invention further discloses a method for manufacturing the electric fluid
heater 100. The method comprising steps of: attaching the first intermediate plate
114 to their adjacent second intermediate plate 116 to form the interspace 136 therebetween,
and filling at least one heating module 122 within the interspace 136 without welding
thereto. The method further comprises a step of: filling at least one heating module
122 within the interspace 136 with thermally conductive type adhesive material. The
adhesive material achieves a homogeneous contact between the plates 112 the entire
heating module surface, thereby avoiding hotspots. The method further comprises a
step of welding a heater housing 166 (also referred as tube 166 throughout the document)
at each interspace 136 of the plate stack 102, and accommodating at least one heating
element 164 (also referred as electrical core 164) within the heater housing 166 and
filling thermally conductive insulation material between the heater housing 166 and
the heating element 164.
[0040] In another embodiment, the electric fluid heater 100 comprises a plate stack 102
having a plurality of intermediate plates. The plate stack 102 provided with an inlet
port 118 and an outlet port 120. The inlet port 118 and the outlet port 120 in fluid
communication with a fluid passage formed through the plate stack 102. The plate stack
102 is arranged in pairs of intermediate plates 102. Each pair includes a first intermediate
plate 114 and a second intermediate plate 116. The first intermediate plate 114 being
joined to the second intermediate plate 116 to form an interspace 136 therebetween
to accommodate at least one heating module 122 without welding thereto.
[0041] In conventional heater arrangements, the heating modules are assembled to the heater
by brazing at high temperature, which may affect the heating element insulation material.
Therefore, the present invention facilitates the arrangement of heating module 122
by sliding the heating module 122 between plates 112. Optionally, the heating module
122 may be slid in between plates 112 and thermally conductive type of adhesive may
be filled between the plates 112 and the heating module 122. The heater 100 further
facilitates early overheating detection due to the short heat transfer path offered
by the multiple plates 112 in contact with the heating module 122. Further, the heater
100 design may be reduced or increased on all three axis based on customer power demands.
Furthermore, the heater 100 further provides efficient heat transfer due to the large
contact area between the heating element and the coolant and long flow path between
the inlet 118 and the outlet 120.
[0042] 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.
1. An electric fluid heater (100), comprising:
a plate stack (102) comprising a first end plate (104), a second end plate (108),
an intermediate plate stack (112) comprising a plurality of intermediate plates (112)
arranged between the first end plate (104) and the second end plate (108), the second
end plate (108) formed with different portions (110A, 110B) that are in fluid communication
with each other, each intermediate plate (112) is divided into different sections
(112A, 112B) respectively corresponding to the different portions (110A, 110B) of
the second end plate (108); the first end plate (104) is provided with an inlet port
(118) in fluid communication with a first fluid path formed through the section (112A)
of the intermediate plates (112) and an outlet port (120) in fluid communication with
a second fluid flow path formed through the section (112B) of the intermediate plates
(112), the inlet port (118) and the outlet port (120) provided in a same side of the
heater (100) adapted to cause the fluid to follow a U-turn trajectory between the
inlet port (118) and the outlet port (120), characterized in that,
the intermediate plate stack (112) is arranged in pairs of plate (114, 116), each
pair (114, 116) includes a first intermediate plate (114) and a second intermediate
plate (116), the first intermediate plate (114) being joined to the second intermediate
plate (116) to form an interspace (136) therebetween to accommodate at least one heating
module (138) without welding thereto.
2. The electric fluid heater (100) of claim 1, wherein each intermediate plate (112)
comprises a first edge portion (140A) and a second edge portion (140B) opposite to
that of the first edge portion (140A), and the first intermediate plate (112) comprises
a depression (146) along a length of the first and second edge portions (140A, 140B)
thereof and the second intermediate plate (116) comprises an elevation (148) complementary
to the depression (146) along a length of the first and second edge portions (140A,
140B) thereof.
3. The electric fluid heater (100) of claim 2, wherein the depression (146) of the first
intermediate plate (114) brought in contact with the elevation (148) of the second
intermediate plate (116) and brazed at the contacting portions defined by the elevation
(148) and depression (146) of the each intermediate plate pair (114, 116), thereby
forming the interspace (136) therebetween.
4. The electric fluid heater (100) of claim 2, wherein the depression (146) of the first
intermediate plate (114) divided into a first section (150A) corresponding to the
first section (112A) of the plate stack (112) and a second section (150B) corresponding
to the second section (112B) of the plate stack (102).
5. The electric fluid heater (100) of claim 2, wherein the elevation (148) of the second
intermediate plate (116) divided into a first section (152A) corresponding to the
first section (112A) of the plate stack (112) and a second section (150B) corresponding
to the second section (112A) of the plate stack (112).
6. The electric fluid heater (100) of claim 2, wherein the depression (146) has at least
one of a rectangular shaped cross section and a square shaped cross section.
7. The electric fluid heater (100) of claim 2, wherein the elevation (148) has at least
one of a rectangular shaped cross section and a square shaped cross section.
8. The electric fluid heater (100) of claim 3, wherein the interspace (136) is a hollow
space.
9. The electric fluid heater (100) of claim 3, wherein the interspace (136) is a tubular
space.
10. A method for manufacturing the electric fluid heater (100) according to claim 1, the
method comprising steps of: (a) attaching the first intermediate plate (114) to their
adjacent second intermediate plate (116) to form the interspace (136) therebetween,
and (b) filling at least one heating module (122) within the interspace (136) without
welding thereto.
11. The method of claim 10, further comprises a step of: filling thermally conductive
type of adhesive material between the heating module (122) and the interspace (136).
12. The method of claim 10, wherein the step (a) further comprises a step of: welding
a heater housing at each interspace (136) of the plate stack (112).
13. The method of claim 12, further comprises a step of: accommodating at least one heating
element within the heater housing and filling thermally conductive material between
the heater housing and the heating element.
14. An electric fluid heater, comprising:
a plate stack having a plurality of intermediate plates, the plate stack provided
with an inlet port and an outlet port, the inlet port and the outlet port in fluid
communication with a fluid passage formed through the plate stack,
characterized in that, the plate stack is arranged in pairs of intermediate plates according to claims
1-12, each pair includes a first intermediate plate and a second intermediate plate,
the first intermediate plate being joined to the second intermediate plate to form
an interspace therebetween to accommodate at least one heating module without welding
thereto.