[0001] The present invention is a light-walled plate heat exchanger, characteristic for
its high efficiency and low production costs, suitable for mass production.
[0002] Known plate exchangers, with the module (the distance between the plates) of 1.5
to 4 mm, are characteristic for a laminar motion of the heat carriers present therein.
In a laminar motion, the heat transfer coefficient is dependent on the Reynolds number
to the power of circa 0.3-0.35. The mechanism of the heat transfer is limited to conduction
of heat within the carrier.
[0003] The light-walled plate heat exchanger, according to the invention, is characteristic
for that it comprises non-planar plates, favourably corrugated broadwise and/or longwise,
stacked alternately on each other with a non-parallel, favourably perpendicular orientation
of the corrugation. The plates are either in contact or are permanently joined together
and create the flow channels for the two heat carriers, ensuring with their shape
an induction of uniaxial or biaxial turbulences of the heat carriers.
[0004] The advantage of the light-walled plate heat exchanger, according to the invention,
is the shape of its plates, which ensures the turbulent nature of motion of the heat
carriers. In a turbulent motion, the heat transfer coefficient is proportional to
the Reynolds number to the power of 0.8. Transverse to the axis of flow, the motion
of the particles of liquid causes intense transfer of heat, thus the heat exchange
surface - as compared to the conventional plate heat exchangers - is much smaller.
[0005] Furthermore, the heat exchanger, according to the invention, is lightweight and small-sized
yet maintains a large heat exchange surface, and has high efficiency achieved from
the unit volume of the exchanger. The force exerted as a result of difference in the
pressure of the agent flowing on both sides of the heat transfer surfaces affects
the small-length structural components, thus the tensions are much smaller than in
case of large-sized flat plates. In the invention thinner wall plates are used, along
with materials of lower durability, while the entire structure of the heat exchanger
is rigid. It is possible to connect the plates permanently in order to increase the
rigidity of the structure. Shape of the plates (outer sides of the flow channels form
the thresholds) and a zigzag axis of flow along the channel entail that both agents
are subject to biaxial movement disorders. The result is a wild (turbulent) motion
of the heat carriers, which results in a higher efficiency and significant reduction
of the heat transfer surface.
[0006] The present invention is visualised as an exemplification in a drawing, in which
Fig. 1 shows an axonometric view on a fragment of the heat exchanger, according to
the invention, and shows and explains the principle of induction of a turbulent flow
of the two heat carriers, whereas the symbols appearing in Fig. 1 represent: I- first
heat carrier, II - second heat carrier, 1 - flow channel of the first heat carrier
shaped within the barrier plate, 1' - first plate of the barrier, 2 - flow channel
of the second heat carrier shaped within the barrier plate, 2' - second plate of the
barrier, 3 and 4 - joints of the barrier plates 1' and 2', A - contact point of the
channels (as a joint of the plates). Fig. 1 shows the flow of the heat carriers I
and II along the flow channels 1 and 2. Fig. 1a, Fig. 1b and Fig. 1c illustrate the
way the disturbances-turbulences occur, explaining that if a heat carrier flows along
the channel 1, then channel 2 constitutes an obstacle through the influence of its
outer side. Vice versa, for the second heat carrier II, channel 1 becomes an obstacle.
Fig. 1 also indicates the contact point of the barriers 1' and 2'.
[0007] Fig. 2 shows an axonometric view of the two barriers (Fig. 2a and Fig. 2b), which
are assembled together with their embossed flow channels facing each other at a right
angle. Made into a package they form an inset of the heat exchanger (Fig. 2c), which
for this version of the structure does not require connecting of the barrier plates.
The flow of the two carriers is structurally separated. The sheets are formed by pressing
and then stacked alternately into a package. The rectilinear shape of the channels
along the flow axis somewhat simplifies the structure, but causes uniaxial disruption,
which can be partly changed by intersecting the rectilinear channels differently than
at a right angle.
[0008] Fig. 3 shows and explains the structure of the heat exchanger according to the invention,
which allows for a biaxial disturbance of flow of the heat carriers through zigzag
shaping of the flow channels of the heat carriers, wherein: I - first heat carrier;
II - second heat carrier, 1 - flow channel of the first heat carrier shaped within
the barrier plate, 1' - first plate of the barrier, 2 - flow channel of the second
heat carrier shaped within the barrier plate, A - contact point of the channels (as
a joint of the plates).
[0009] The light-walled plate heat exchanger, according to the invention, allows to take
into account diverse properties of the heat carriers by differentiating the depth
of the flow channels (for first and second barrier) and varying the cross-sections
of the flow channels (the cross-section may be in particular: trapezoidal, sinusoidal,
rectangular, semi-circular, etc.). The plates can be made especially of metals, such
as steel, copper and its alloys, aluminium and its alloys, or ceramics.
[0010] Utilisation of such different materials is linked with a variety of heat carriers
used and their parameters, which in turn allows to connect the inset of the heat exchanger
(barrier plates) with one another by different methods, in particular: adhesive bonding,
soldering (hard and soft), braze welding, welding, fusion welding. However, for several
solutions there is no need for connecting, and it is sufficient to stack the plates
into packets.
[0011] The solution according to the invention allows for a modular construction of the
heat exchangers from the same basic elements as barrier plates.
1. The light-walled plate heat exchanger, characteristic in that it comprises non-planar, favourably corrugated lengthwise and / or broadwise plates
(1' and 2') stacked alternately with a non-parallel favourably perpendicular orientation
of the corrugation, whereby the plates are in contact or are permanently connected
and create flow channels (1 and 2) for the two heat carriers (I and II), which ensure
with their shape an induction of uniaxial or biaxial turbulences of the heat carriers
(I and II).
