U.S. patent application number 17/261569 was filed with the patent office on 2021-08-26 for plate heat exchanger with reinforced covers and method for the production of said reinforced covers and their assembly.
The applicant listed for this patent is Zilmet SpA. Invention is credited to Riccardo Benettolo, Michele Pirovano.
Application Number | 20210262734 17/261569 |
Document ID | / |
Family ID | 1000005626473 |
Filed Date | 2021-08-26 |
United States Patent
Application |
20210262734 |
Kind Code |
A1 |
Benettolo; Riccardo ; et
al. |
August 26, 2021 |
Plate heat exchanger with reinforced covers and method for the
production of said reinforced covers and their assembly
Abstract
A plate heat exchanger includes a pack of superimposed heat
exchanger plates, and has two cover plates mounted on the side
portions of the first heat exchanger plate. The surface area of
each of the two cover plates is smaller than half of the surface
area of said first heat exchanger plate.
Inventors: |
Benettolo; Riccardo; (Limena
(PD), IT) ; Pirovano; Michele; (Limena (PD),
IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Zilmet SpA |
Limena (PD) |
|
IT |
|
|
Family ID: |
1000005626473 |
Appl. No.: |
17/261569 |
Filed: |
July 18, 2019 |
PCT Filed: |
July 18, 2019 |
PCT NO: |
PCT/IB2019/056144 |
371 Date: |
January 20, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F28D 9/005 20130101;
F28F 3/046 20130101; F28F 2225/00 20130101 |
International
Class: |
F28D 9/00 20060101
F28D009/00; F28F 3/04 20060101 F28F003/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 24, 2018 |
IT |
102018000007453 |
Claims
1. A plate heat exchanger (1) comprising: a pack (10) of
superimposed heat exchanger plates (101) provided with alternating
ridges (102) and depressions (103), said alternating ridges and
depressions defining, together with the ridges (102) and
depressions (103) present on another facing heat exchanger plate
(101), circuits for the heat exchange fluids, and through-holes
(104) configured to convey two of the heat exchange fluids in
spaces between the heat exchanger plates following at least two
hydraulically isolated circuits, wherein each heat exchanger plate
(101) is rectangular in shape, wherein the heat exchanger comprises
two cover plates (21, 22) mounted on a first one (107) of said heat
exchanger plates (101), wherein a surface area of each of said two
cover plates (21, 22) is smaller than half the surface area of said
first heat exchanger plate (107) and wherein each of said two cover
plates (21, 22) further comprises: a pair of second holes (23, 231)
shaped and positioned to correspond to said through-holes (104) in
the heat exchanger plates; and a metal ring (3, 3'), positioned to
surround one of said second holes (231) and on a lower area of said
first heat exchanger plate (107) where one of the through-holes
(104) for one of the heat exchange fluids is made, wherein said
metal ring (3, 3') is adapted to guarantee a hermetic seal between
one of said cover plates (21 22) and said first heat exchanger
plate (107).
2. The plate heat exchanger (1) according to claim 1, wherein an
edge (232) of the one of said hole (231) in one of said cover
plates (21, 22) is bent towards one side of the one of said cover
plates (21, 22), forming said metal ring (3') in a single solid
piece with the one of said cover plates (21, 22).
3. The plate heat exchanger (1) according to claim 2, wherein the
edge of said metal ring (3') is further bent outwardly to form a
flange (3 G).
4. The plate heat exchanger (1) according to claim 1, wherein a
shape and size of said two cover plates (21, 22) correspond to side
portions of said first heat exchanger plate (107), the side
portions comprising said through-holes (104) and being located in
proximity to the transverse edges (16).
5. The plate heat exchanger (1) according to claim 4, wherein each
of said two cover plates (21, 22) has a symmetrical shape, so that
each of said two cover plates can be mounted either on a right side
or a left side of the pack (10).
6. The plate heat exchanger (1) according to claim 1, wherein each
of said two cover plates (21, 22) comprises one or more shaped
tabs, which project from an edge (24) facing a center of said first
one (107) of said heat exchanger plates (101) and is configured to
be inserted in one of said depressions (103) provided on said first
one (107) of said heat exchanger plates (101).
7. The plate heat exchanger (1) according to claim 1, wherein said
two cover plates (21, 22) provide a seat or base (27) for an
application of fixing stud bolts and is provided with holes, seats
or coupling means for installation of means for fixing said two
cover plates (21, 22) one of the at least two hydraulically
isolated circuits.
8. The plate heat exchanger (1) according to claim 1, wherein said
first one (107) of said heat exchanger plates is equal to at least
one of the other heat exchanger plates (101) forming the pack
(10).
9. The plate heat exchanger (1) according to claim 1, wherein said
heat exchanger plates (101) are all identical or of two different
types in order to define hydraulic circuits with different flow
resistance.
10. A method of making the plate heat exchanger (1) according to
claim 1, comprising the following steps: preparing and assembling
said pack (10) of superimposed heat exchanger plates; preparing a
steel sheet; performing a stamping step of said steel sheet,
wherein one or more of said cover plates (21, 22) are stamped at a
time; drilling said steel sheet forming said pair of second holes
in pre-determined positions; applying or forming said metal rings
(3) on said steel sheet; shearing said steel sheet in at least one
shearing step to cut said cover plates (21, 22); and assembling
said plate heat exchanger (1), wherein said cover plates (21, 22)
are applied to two side portions of the first heat exchanger plate
(107) of said pack (10) of heat exchanger plates.
11. The method according to claim 10, further comprising a step of
bending said steel sheet to form tabs of said cover plates (21,
22).
12. The method according to claim 10, further comprising a step of
coupling said steel sheet with a copper sheet suitable for
subsequent braze welding.
13. The method according to claim 10, wherein two or more of said
steps are grouped and carried out in a same station.
Description
[0001] The present patent relates to plate heat exchangers and in
particular concerns a new plate heat exchanger with reinforced
cover plates and method for the production of said reinforced cover
plates and their assembly.
[0002] The prior art includes plate heat exchangers comprising at
least two separate circuits respectively for the circulation of a
primary fluid and a secondary fluid, where those circuits are
defined by a plurality of exchange plates with facing surfaces,
featuring ridges and depressions, generally distributed in a
herringbone pattern.
[0003] The heat exchangers of the prior art are made by stacking
the plates in question alternating the rotation of every other one
by 180.degree. so that the ridges and depressions of one plate are
crossed with respect to the ridges and depressions of the adjacent
plate.
[0004] Usually the plates are called symmetric when the ridges and
depressions are such that the sections of the channels of both
paths used by the two fluids are substantially equal, that is,
resulting in equal flow resistance with equal flows.
[0005] These kinds of heat exchangers are commonly used to heat
water for domestic use using the hot fluid of the heating
system.
[0006] Prior art also includes specially shaped plates such that
the section for the heating water is wider than that used for the
domestic water system and therefore the flow resistance is
differentiated.
[0007] For this purpose the prior art includes so-called asymmetric
heat exchangers, that is, formed by plates comprising ridges with a
different shape than the depressions, such as, for example, flat
ridges to make the section of the channel even wider.
[0008] Plates having different flow resistances with equal flows
are also known, obtained by increasing the pitch of the ridges,
that is, the distance between the ridges of two adjacent channels.
This type of heat exchanger is suitable for the exchange between
water and cooling fluid, where the water flows through the circuit
having lower flow resistance. In this case the plates are not
rotated 180.degree., but alternate with each other as they have two
different configurations.
[0009] Regardless of the size and depth of the ridges and
depressions, the intermediate exchange plates of heat exchangers of
the prior art are normally made of very thin metal sheets, usually
steel or other material suitable for the manufacturing of heat
exchangers.
[0010] The heat exchanger pack is closed by a cover plate which has
a shape corresponding to the exchange plates, and is equipped with
water inlet and outlet holes and holes for the connection to the
system's piping.
[0011] Said cover plate is generally more rigid, usually made of
steel sheet and may have a corrugated surface, that is, with ridges
and depressions, which further increase its stiffness, or an
essentially flat surface.
[0012] The function and purpose of the cover plate is to withstand
the pressure exerted by the fluids towards the outside, to house
the connections to the boiler unit, and to create the seat for the
fastening systems, such as stud bolts, fittings or the like.
[0013] There is currently a need to minimize the weight of boiler
units and the use of raw materials. For this purpose, there are
corrugated cover plates in the prior art which also work as
exchange plates, thus being able to reduce the number of
intermediate exchange plates.
[0014] Document CN101184574 A relates to a plate heat exchanger
comprising adapter plates installed between the cover plate and the
inlets and outlets of the system. Each of said adapter plates has
two holes for the connection with the heat exchanger plates. On the
face of said adapter plates intended to be coupled to the outer
side of the cover plate, there are depressions intended to be
filled with welding material for the subsequent joining to the
cover plate itself.
[0015] The object of the present patent is a new plate heat
exchanger with reinforced cover plates and a method for producing
said reinforced cover plates and their assembly.
[0016] The main object of the present invention is to decrease the
weight of the heat exchanger, minimizing the weight of the cover
plate.
[0017] Another important object of the present invention is to
speed up the procedures for manufacturing and assembling the heat
exchanger, thanks to the fact that it is possible to eliminate some
welding steps in a preferred embodiment. The cover plates of the
new heat exchanger can in fact be conveniently made of a single
part, obtained by shearing, stamping and deforming a metal sheet,
with no need for further welding steps. It follows that production
costs are reduced and the finished piece is more resistant.
[0018] A further object of the present invention is to minimize the
use of raw materials to make the heat exchanger and the cover
plates in particular.
[0019] Still another object of the present invention is to enable
the assembly of a plate heat exchanger pack where all the plates,
including those at the ends, are made with the same stamping
process, thus obtaining a pack on which the cover plates are
applied as described and claimed below.
[0020] Yet another object of the present invention is to minimize
thermal inertia when the exchanger is fully operational.
[0021] A further object of the present invention is to enable the
use of exchange plates all with the same shape, preferably also
with the same thickness, so that they can be produced with the same
production methods.
[0022] These and other direct and complementary objects are
achieved by the new plate heat exchanger with reinforced cover
plates and method for the production of said reinforced cover
plates and their assembly.
[0023] In its main components the new plate heat exchanger
comprises at least one pack of exchange plates, that is, a series
of stacked plates braze welded together, to confine the fluids
inside, each provided with alternating ridges and depressions
arranged preferably and substantially in a herringbone pattern or
arranged in two directions intersecting each other, and holes for
the circulation of at least two heat exchange fluids, suited to
convey said two fluids in the spaces between the plates following
at least two hydraulically isolated circuits.
[0024] The exchanger therefore comprises at least two separate
circuits for a primary fluid and a secondary fluid, each of said
two circuits being defined by a pair of said facing exchange
plates, provided with said ridges and depressions.
[0025] Said exchange plates may all be of the same type or of two
different types to create circuits with a different flow
resistance.
[0026] Said exchange plates making up the pack are normally made of
thin shaped steel sheets, braze welded together with copper or
another material suitable for braze welding.
[0027] In particular, each heat exchanger plate has a substantially
rectangular shape, with two longitudinal sides and two transverse
sides, and where said holes for the circulation of the fluids are
located near said transverse sides, close to the corners, while the
remaining surface of the plate is corrugated, with said ridges and
depressions that create, with a facing plate, the circuits for the
circulation of fluids.
[0028] On each transverse side, a first through-hole for the
circulation of fluid is made in a lowered area, while a second hole
is made on a raised area, in inverted or symmetrical positions with
respect to the holes in the opposite transverse side.
[0029] On the first of said heat exchanger plates making up the
pack, two cover plates are mounted, where each of said cover plates
is smaller than half of the surface of said first heat exchanger
plate.
[0030] Said first heat exchanger plate is identical to the
intermediate plates of the pack.
[0031] Each of said cover plates also has a shape and dimensions
corresponding to the side portion of said first heat exchanger
plate, that is, to the portion closer to a transverse edge and
which comprises said holes for the circulation of fluids.
[0032] In the preferred embodiment, said cover plates have the same
symmetrical shape, substantially rectangular, with four rounded
corners or with the two short sides replaced by semicircles.
[0033] Each of said cover plates is furthermore provided with holes
shaped and positioned so that they correspond to said holes in the
heat exchanger plates.
[0034] Said cover plates are mounted at the level of said side
portions of said first heat exchanger plate so that the holes in
said cover plates are in a position corresponding to said holes in
the stacked heat exchanger plates.
[0035] Each of these cover plates is made of steel sheet or in any
case of a material normally used or in any case suitable for use in
plate heat exchangers.
[0036] At the level of a hole in said cover plates there may be a
metal ring, suited to ensure the seal between the cover plate and
the first heat exchanger plate, and wherein said metal ring is
located at the lowered area of said first heat exchanger plate
where the through-hole for the fluid is made, in order to convey
said fluid from the cover plate to the channels inside the heat
exchanger.
[0037] Said metal ring can be joined to said cover plate, for
example by welding, or, more preferably, by deformation of the
cover plate itself at the hole. In other words, the edge of the
hole is deformed and/or stamped so as to create said metal
ring.
[0038] Said metal ring therefore has the shape of an open cylinder,
joined to the cover plate. Said metal ring preferably also
comprises a flange on the circular edge of said open cylinder, said
flange being for example obtained by further bending the
cylindrical wall itself. This embodiment has the advantages
described above.
[0039] Said cover plates are positioned and centered on the first
plate of the pack preferably by spot welding or arc welding or
other mechanical processes in order to keep said cover plates
centered with the holes in the pack and in the correct position
until the braze welding step with which they are permanently welded
to the pack.
[0040] Alternatively or in combination with the above, in a
possible embodiment, each of said cover plates may comprise shaped
tabs, protruding from the edge facing the center of said first
exchange plate, and suited to be inserted in a depression made on
said first exchange plate itself. This facilitates the centering
and assembly of the cover plates and also guarantees proper
positioning.
[0041] The tabs have a shape and dimensions that are a function of
the conformation, the orientation, and the possible curvature of
the depressions of said first exchange plate. Said cover plates are
preferably of two types, one right and one left, according to the
side of the exchanger on which they are installed.
[0042] Said cover plates furthermore act as a seat or base for the
application of the fixing stud bolts and can also be suitably
provided with holes, seats or coupling means in general for the
installation of fixing means to the hydraulic circuit, such as
fittings or the like. The present patent also relates to the
production method of said cover plates and their assembly to the
pack of exchange plates.
[0043] The production method comprises the following fundamental
steps, the order of which are interchangeable and some of which can
even be eliminated or grouped in one or more steps: [0044]
preparation and assembly of the pack of stacked heat exchanger
plates according to the known art; [0045] preparation of a steel
sheet, preferably in the form of a continuous strip and possibly
coupled with a copper sheet for subsequent braze welding; [0046]
use of said steel sheet in at least one stamping step, where one or
more cover plates are stamped at a time; [0047] use of said steel
sheet in at least one drilling step, where the holes for the
circulation of the fluids are made in pre-determined positions;
[0048] use of said steel sheet in at least one step for the
application of said metal rings, where they are coupled or made,
for example by spot welding, deformation, mechanical assembly or
welding, said metal rings being necessary to create a tight seal
between the cover plates and the first heat exchanger plate in the
lowered areas of the latter where the through-holes for the
circulation of each of the two fluids are made; the hermetic seal
is guaranteed by the particular shape of said metal rings which
substantially comprise an open cylinder joined to the sheet with
which the cover plates are made and preferably also a flange;
[0049] use of said steel sheet in at least one shearing step, where
one or more cover plates are cut at a time; [0050] use of said
steel sheet in at least one bending step, where the tabs of said
cover plates are possibly created; [0051] plate heat exchanger
assembly, where said cover plates are applied to the two side
portions of the first heat exchanger plate of said pack of heat
exchanger plates; said assembly step provides, for example, as
mentioned, for the spot welding or arc welding or other mechanical
positioning/fastening process of the cover plates to the first heat
exchanger plate so that the respective holes are centered.
[0052] Said stamping, drilling and shearing, as well as the bending
step of the possible tabs and application/formation of said metal
rings, can be carried out in separate and distinct steps or they
can be carried out in one or more grouped steps.
[0053] For example, said stamping, drilling and shearing steps can
all be performed in a single step and processing station.
[0054] The characteristics of the present invention will be better
clarified by the following description with reference to the
drawings, attached by way of a non-limiting example.
[0055] FIG. 1 shows a three-dimensional view of the completely
assembled plate heat exchanger (1), while FIGS. 2 and 3 show a
section view and a plan view respectively.
[0056] FIG. 4 shows a three-dimensional view of cover plates (21)
to be installed on one side of a heat exchanger plate pack (10),
for example on the left.
[0057] FIG. 5 shows a three-dimensional view of cover plates (22)
to be installed on one side of a heat exchanger plate pack (10),
for example on the right.
[0058] In FIGS. 1 to 5 each of said cover plates (21, 22) has an
asymmetrical shape, according to a first possible embodiment. In
contrast, a preferred embodiment of said cover plates (21, 22) is
schematized in FIG. 6, where said cover plates (21, 22), whether
they are on the right or on the left, have a symmetrical,
substantially rectangular shape where the shorter sides are made up
of semicircles.
[0059] FIG. 7 shows a section view of a cover plate (21, 22) at the
level of the hole (231) made in the cover plate (21, 22) itself,
where the metal ring (3') obtained by deformation and/or stamping
of the edge (232) of the hole (231) itself can be seen. In this
particular embodiment, said metal ring (3') is a single solid piece
with said cover plate (21, 22), thus without the need for welding
or mechanical joining in general.
[0060] The plate exchanger (1) comprises in its main parts at least
one pack of exchange plates (10) that is a series of superimposed
plates (101) in a pack.
[0061] Each of said exchange plates (101) in turn comprises
alternating ridges (102) and depressions (103), arranged preferably
and substantially in a herringbone pattern or arranged in two
intersecting directions.
[0062] Each of said exchange plates (101) is also provided with two
pairs of through-holes (104) for the passage of at least two
heat-transfer fluids, said holes (104) being made at the level of
lowered and raised areas alternately positioned on the two sides of
the plates (101), to convey said two fluids into the spaces between
the plates following at least two hydraulically isolated
circuits.
[0063] Said exchange plates (101) forming said pack (10) are
normally made of thin shaped steel sheets.
[0064] Each exchange plate (101) has a substantially rectangular
shape, with two longitudinal sides (105) and two transverse sides
(106), and where said fluid through-holes (104) are formed near
said transverse sides (106), close to the corners.
[0065] Two cover plates (21, 22) are mounted on the first exchange
plate (107) of said pack (10), each shaped in correspondence with
the transverse side for which it is intended.
[0066] Each of said cover plates (21, 22) has a shape and
dimensions substantially corresponding to the side portions of said
first exchange plate (107) close to the two transverse sides (106)
and comprises a pair of said holes (23, 231) corresponding to said
holes (104) in the exchange plates (101).
[0067] In the example of FIG. 6, each of said cover plates (21, 22)
has a symmetrical shape, so that they can be mounted either on the
right or the left of the pack (10).
[0068] Each of said cover plates (21, 22) is made of steel sheet or
in any case of material normally used or in any case suitable for
use in plate heat exchangers.
[0069] As can be seen from FIGS. 1, 2 and 3, said cover plates (21,
22) also act as a seat or base (27) for the application of the
fixing stud bolts and can also be suitably provided with holes,
seats or coupling means in general for the installation of fixing
means to the hydraulic circuit, such as fittings or the like.
[0070] At least one hole (231) in one or both of said cover plates
(21, 22) may be provided with a metal ring (3, 3'), necessary to
create a hermetic seal between said cover plates (21, 22) and said
first exchanger plate (107) at the lowered area in which the
through-hole (104) for a fluid is made, in order to convey said
fluid from the cover plate (21 22) to the internal channels of the
exchanger.
[0071] In the embodiment in FIGS. 4 and 5, said metal ring (3) is
for example applied at the level of said hole (231) in the cover
plate (21, 22) and constrained/coupled by means of spot welding
and/or deformation and/or welding and/or mechanical assembly in
general. Said ring (3) is therefore a distinct piece from the cover
plate (21, 22) and joined to it during the production/assembly
step.
[0072] In the specific and preferred but not exclusive embodiment
in FIG. 7, said metal ring (3') is a single piece with respect to
the cover plate (21, 22) being obtained by means of deformation
and/or stamping of the edge (232) of the hole (231) in the cover
plate (21, 22) itself.
[0073] In this case, the edge (232) of said hole (231) in said
cover plate (21, 22) is bent towards one side of the cover plate
(21, 22) itself, that is, the side intended to be turned towards
said first exchanger plate (107), thus forming said metal ring (3')
in a single solid piece with said cover plate (21, 22).
[0074] Said metal ring (3') is therefore substantially formed by an
open cylinder. The embodiment in FIG. 7 shows how said metal ring
(3') can further comprise a flange (31') suited to ensure a tight
seal in the subsequent assembly of each cover plate (21, 22) to the
first exchange plate (107) of the pack (10).
[0075] Said flange (31') is also preferably obtained by
deformation/bending.
[0076] Each of said cover plates (21, 22) may also comprise, but
not necessarily, shaped tabs (24, 25), protruding from the edge
(26) facing the center of said first exchange plate (107), and
suited to be inserted in one of said depressions (103) of said
first exchange plate (107) itself.
[0077] Therefore, with reference to the preceding description and
the attached drawings the following claims are made.
* * * * *