U.S. patent application number 09/990712 was filed with the patent office on 2003-05-22 for corrugated fin assembly.
Invention is credited to Ernst, Donald M., Toth, Jerome E..
Application Number | 20030094273 09/990712 |
Document ID | / |
Family ID | 25536461 |
Filed Date | 2003-05-22 |
United States Patent
Application |
20030094273 |
Kind Code |
A1 |
Toth, Jerome E. ; et
al. |
May 22, 2003 |
Corrugated fin assembly
Abstract
The apparatus is an assembly of cooling fins attached to pipes
or heat pipes. The fins are formed into a corrugated configuration
of troughs and peaks with large sections of the peaks removed to
permit air flow along the depths of the troughs as well as along
the lengths of the troughs. Holes are also formed into the fins to
accept and grip a pipe or heat pipe. The preferred embodiment has
holes surrounded by split collars formed into each fin, with the
collars aligned to accept and grip the pipe.
Inventors: |
Toth, Jerome E.; (Hatboro,
PA) ; Ernst, Donald M.; (Lancaster, PA) |
Correspondence
Address: |
Samuel W. Apicelli
Duane Morris LLP
P.O. Box 1003
Harrisburg
PA
17108-1003
US
|
Family ID: |
25536461 |
Appl. No.: |
09/990712 |
Filed: |
November 21, 2001 |
Current U.S.
Class: |
165/183 ;
165/181 |
Current CPC
Class: |
F28F 1/128 20130101 |
Class at
Publication: |
165/183 ;
165/181 |
International
Class: |
F28F 001/20; F28F
001/14; F28F 001/36 |
Claims
What is claimed is:
1. A fin assembly comprising a corrugated sheet having alternating
peaks and troughs in which portions of said peaks are removed to
permit air flow in the direction of the depths of the troughs.
2. The fin assembly according to claim 1 wherein said fins include
at least one hole to hold a pipe.
3. The fin assembly according to claim 1 wherein said portions of
said peaks are removed from a flat sheet before said flat sheet is
folded so as to form said corrugated sheet.
4. A fin assembly comprising a corrugated fin assembly including a
plurality of fins with a split collar formed on each fin, said
collar being expanded by and holding a pipe which passes through
said fins.
5. The fin assembly according to claim 4 wherein said split collars
are formed in a flat sheet before said flat sheet is folded to form
said corrugated fin assembly.
6. The fin assembly according to claim 5 wherein said split collars
include a central hole and at least two radially extending slits so
that said split collars are formed by pushing a pipe through said
central holes so as to expand that portion of said flat sheet
extending between said slit adjacent to said hole.
7. A method for fabricating a fin assembly, comprising: (A)
providing a length of fin material, the fin material capable of
being formed into a corrugated assembly of parallel spaced fins
defining peaks at a top surface and defining corresponding troughs
at a bottom surface with air channels created by the parallel
spaced fins, the peaks and troughs each including a central section
bounded by a pair of end sections; (B) removing a portion of said
central section of at least some of said peaks so as to form top
surface slots in said corrugated fin material; (C) removing a part
of said central section of at least some of said troughs so as to
form bottom surface slots in said corrugated fin material; and (D)
permitting airflow through said top and bottom surface slots in a
direction substantially perpendicular to existing air flow through
said air channels when said fin material is formed into said
corrugated assembly of parallel spaced fins.
8. A method according to claim 7 further comprising forming a
plurality of uniformly spaced apertures in the length of said fin
material.
9. A method according to claim 8 further comprising spacing said
plurality of uniformly spaced apertures to define a straight
aperture alignment capable of receiving a pipe through said
apertures in said fin material when said fin material is formed
into said corrugated assembly.
10. A fin assembly comprising: a length of fin material, said fin
material being capable of being formed into a corrugated assembly
of parallel spaced fins defining peaks at a top surface and
defining corresponding troughs at a bottom surface with air
channels created by the parallel spaced fins, said peaks and
troughs each including a central section bounded by a pair of end
sections; means for removing a part of said central section of at
least some of said peaks to form top surface slots in said
corrugated fin material; means for removing a part of said central
section of at least some of said troughs to form bottom surface
slots in said corrugated fin material, whereby air flow is
permitted through said top and bottom surface slots in a direction
substantially perpendicular to existing air flow through said air
channels when said fin material is formed into said corrugated
assembly of parallel spaced fins.
11. A fin assembly according to claim 10 further comprising a
plurality of uniformly spaced apertures in said length of fin
material.
12. A fin assembly according to claim 11 further comprising means
for spacing said plurality of uniformly spaced apertures to define
a straight aperture alignment capable of receiving a pipe device
through said apertures in said fin material when said fin material
is formed into said corrugated assembly.
13. A fin assembly according to claim 10 wherein said top surface
slots and said bottom surface slots are formed in said fin material
before said fin material is corrugated.
14. A process for transferring heat which comprises incorporating
into a heated structure the fin assembly of claim 10 and
transferring heat from the heated structure by inserting the heated
structure through said plurality of uniformly spaced apertures to
generate natural convection in said fin assembly.
15. A fin assembly comprising: a sheet of metal folded so as to
form a plurality of alternating peaks and troughs with a wall
extending between each of said peaks and troughs so as to define a
plurality of fins wherein a central portion of each of said peaks
is removed to form a through-opening that is bounded by
spaced-apart straps of said sheet metal so as to permit air flow
parallel to said troughs; and wherein each of said fins define a
hole and at least two slits extending radially from said hole and
through a portion of said fin so that when a pipe is inserted
through said hole a portion of said fin projects outwardly in the
direction of movement of said pipe.
16. A fin assembly according to claim 15 wherein said pipe
penetrates each said fin and is held in thermal contact with each
fin by a that portion of said fin that projects outwardly in the
direction of movement of said pipe.
17. A fin assembly according to claim 15 wherein said straps are
portions of said peaks and maintain a selected fin to fin
spacing.
18. A fin assembly according to claim 15 wherein said holes are
substantially coaxial to one another.
19. A fin assembly according to claim 18 wherein said hole is
centrally located in each fin and said slit comprises a cruciform
shape.
20. A fin assembly according to claim 19 wherein when said pipe
penetrates said holes, the material of said fin that defines said
cruciform slits deforms outwardly so as to create a plurality of
gripping fingers that engage said pipe.
21. A fin assembly according to claim 19 wherein said holes and
slits form a split collar.
22. A fin assembly according to claim 15 wherein said straps are
substantially flat.
23. A fin assembly according to claim 15 wherein said straps are
substantially rounded.
24. A fin assembly comprising: a sheet of metal folded so as to
form a plurality of alternating peaks and troughs with a wall
extending between each of said peaks and troughs so as to define a
plurality of fins wherein a central portion of each of said peaks
is removed to form a through-opening that is bounded by
spaced-apart straps of said sheet metal so as to permit air flow
parallel to said troughs; and wherein each of said fins define a
hole and at least two slits extending radially from said hole and
through a portion of said fin and having a plurality of concentric
preformed bend-lines positioned radially outwardly from said hole
so that when a pipe is inserted through said hole a portion of said
fin bends along at least one of said concentric bend-lines and
projects outwardly in the direction of movement of said pipe.
25. A fin assembly comprising: a sheet of metal folded so as to
form a plurality of alternating peaks and troughs with a wall
extending between each of said peaks and troughs so as to define a
plurality of fins wherein a central portion of each of said peaks
is removed to form a through-opening that is bounded by
spaced-apart straps of said sheet metal so as to permit air flow
parallel to said troughs; and wherein each of said fins define an
open ended slot extending through a portion of said fin and sized
so as to accept a pipe.
26. A fin assembly according to claim 25 comprising an opening
defined within each of said fins and located at an end of said
slot.
27. A fin assembly according to claim 25 wherein said plurality of
fins define a plurality of axially aligned slots so as to form a
receptacle-passageway through said fin assembly.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to cooling fin
structures, and more particularly to an assembly of cooling fins
attached to a pipe or heat pipes and the method of attaching such
fins.
BACKGROUND OF THE INVENTION
[0002] Multiple fin assemblies are commonly used for transferring
heat. This heat transfer is frequently between a liquid or vapor
flowing in pipes that are in contact with the fins, and air flowing
past the fins. Sometimes the fins are in contact with a second
liquid rather than air. Perhaps the most common use of such a
configuration is a simple household radiator in which hot water
flows through a copper pipe that passes through a central hole
located in individual aluminum fins. Here, the fins surround the
pipe, with the pipe being bonded to the fins at edges that define
the holes. The copper pipe heats the fins, which in turn transfer
the heat into the air around the pipe by natural convection.
[0003] In more sophisticated installations, it has also been common
to use a similar structure to transfer heat from a heat pipe to
surrounding air. Here too, the fins are attached to the heat pipe
by passing the heat pipe through a hole in the fins. The attachment
method is usually brazing, gluing, soldering, mechanical or
hydraulic expansion, or welding of the fins to the heat pipe.
Unfortunately, this prior art means of attaching fins to pipes is
time consuming and expensive. It involves the bonding of each
individual fin to the pipe, and regardless of the specific bonding
material, the technique requires applying the solder, brazing
material, or epoxy to each individual fin, or an additional
manufacturing process step to expand the tube mechanically or
hydraulicly.
[0004] It would be very beneficial and economical to be able attach
fins to a pipe or heat pipe without handling each fin separately
and without the use of bonding materials which have to be
discretely applied to the fin structure.
SUMMARY OF THE INVENTION
[0005] The present invention provides a unified assembly of fins
attached to a pipe or heat pipe without the use of any intermediate
bonding material. Because all the fins are formed as a single free
standing assembly, the attachment to the pipe or heat pipe is
greatly simplified.
[0006] In a preferred embodiment, fins are folded or corrugated to
form a serpentine surface with alternating peaks and troughs. The
troughs, as viewed from one side, form the peaks as viewed from the
opposite side. However, unlike prior art folded assemblies of fins,
the fins of the present invention have large sections along the
lengths of their peaks removed. These cut out portions along the
peaks of the corrugated fins can easily be punched out before the
corrugations are formed, when the sheet is still flat, or can be
removed after folding. Typically, these sections are removed from
all but a small portion of the ends of the peaks, so that in the
finished assembly it appears as if alternating sets of fins have
been strapped together in a few separate locations. These remaining
sections of the peaks hold the fins together to make a single
assembly, and also assure that the fins will remain properly
separated. This configuration yields fins which do not act like
normal corrugated fins.
[0007] In another embodiment of the invention, a fin assembly is
provided comprising a sheet of metal folded so as to form a
plurality of alternating peaks and troughs having a wall extending
between each of the peaks and troughs. A central portion of each of
the peaks is removed to form a through-opening that is bounded by
spaced-apart straps of the sheet metal so as to permit air flow
parallel to the troughs. Each of the walls defines a hole and at
least two slits extending radially from the hole and through a
portion of the wall so that when a pipe is inserted through the
hole, a portion of the wall projects outwardly in the direction of
movement of the pipe.
[0008] Typical corrugated fins can only be used with continuous air
flow along the troughs of the fins, meaning they can only be
oriented in one direction to take advantage of natural or forced
convection. For natural convection, the troughs and peaks must be
oriented nearly vertically. However, the fins of the present
invention are multi-directional. Since the portions of the peaks
which remain to hold the fins together are relatively small
compared to the sections removed from the peaks, convection can
generate air flow in the direction along the depths of the troughs,
and that convection has essentially the same cooling effect as it
would have on independent fins of the same surface area. This makes
fins of the present invention particularly suitable for the many
installations in which natural convection or undirected forced air
is the cooling mode.
[0009] The fin assembly of the invention is also attached to pipes
or heat pipes in a different way than conventional fins. The
attachment structure of the present invention comprises a series of
holes, one or more in each folded fin, with the holes in all the
folded fins aligned so that pipes or heat pipes can be inserted
through all the aligned holes. However, the attachment of the fins
to the pipes or heat pipes uses no bonding material. Instead, each
hole in a fin is formed with radiating slits which form clamping
fingers which act as springs by storing elastic energy and thereby
exerting a retaining force against the pipes. A concentric radial
pattern may be preformed into the material separating the slits so
as to provide preferred bend-lines in the material. In a preferred
embodiment, the diameter of the pipes are sized so that the pipes
are forced into the holes and cause the fingers to bend outward to
form a collar. Such split collars can also be formed at the same
time the hole is punched into the fin by drawing out the material
on the edge of the hole. However, a simpler manufacturing process
is provided when the collars are formed by the pipe itself as it is
forced through holes with radial cuts extending out from the
holes.
[0010] From a manufacturing standpoint it is much easier to form
the holes and radial cuts before the fins are folded, so that the
holes are punched and the material removed from the future peaks on
a simple flat sheet of material. It will be understood that if
collars are to be formed in a flat sheet that is ultimately going
to be folded into a fin assembly, adjacent collars in the flat
sheet must point in opposite directions. That is, in a flat
horizontal sheet one collar must protrude down from the sheet while
the collars adjacent to it must protrude up. Thus, after the sheet
is folded to form the parallel fins of the assembly, the collars
will all be pointing in one direction, and therefore be arranged so
as to accept a pipe that is pushed through the collars.
[0011] The present invention thereby furnishes a more easily
manufactured and assembled cooling fin assembly on a pipe or a heat
pipe than has previously been available.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] These and other features and advantages of the present
invention will be more fully disclosed in, or rendered obvious by,
the following detailed description of the preferred embodiment of
the invention, which is to be considered together with the
accompanying drawings wherein like numbers refer to like parts and
further wherein:
[0013] FIG. 1 is a perspective view of the preferred embodiment of
a corrugated fin assembly formed in accordance with the invention,
penetrated by and attached to a pipe;
[0014] FIG. 2 is a layout view of a portion of a flat sheet used to
form the fin assembly of the preferred embodiment of the invention;
and
[0015] FIG. 3 is a perspective view of a corrugated fin assembly
formed in accordance with an alternative embodiment of the
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0016] This description of preferred embodiments is intended to be
read in connection with the accompanying drawings, which are to be
considered part of the entire written description of this
invention. In the description, relative terms such as "horizontal,"
"vertical," "up," "down," "top" and "bottom" as well as derivatives
thereof (e.g., "horizontally," "downwardly," "upwardly," etc.)
should be construed to refer to the orientation as then described
or as shown in the drawing figure under discussion. These relative
terms are for convenience of description and normally are not
intended to require a particular orientation. Terms including
"inwardly" versus "outwardly," "longitudinal" versus "lateral" and
the like are to be interpreted relative to one another or relative
to an axis of elongation, or an axis or center of rotation, as
appropriate. Terms concerning attachments, coupling and the like,
such as "connected" and "interconnected," refer to a relationship
wherein structures are secured or attached to one another either
directly or indirectly through intervening structures, as well as
both movable or rigid attachments or relationships, unless
expressly described otherwise. The term "operatively connected" is
such an attachment, coupling or connection that allows the
pertinent structures to operate as intended by virtue of that
relationship.
[0017] FIG. 1 is a perspective view of the preferred embodiment of
corrugated fin structure 10 of the invention in which pipe 12
penetrates each fin 14 and is held in thermal contact with each fin
by a split collar 16. Fins 14 are formed by folding a flat sheet
into the serpentine configuration shown for corrugated fin assembly
10.
[0018] Fin assembly 10 differs from conventional corrugated fin
assemblies because central portions of peaks 18 of the corrugations
are removed to form slots 20. Although in FIG. 1 they are
substantially hidden by fins 14, slots similar to slots 20 are also
removed from lower peaks 22 of fin assembly 10.
[0019] Slots 20 give fin assembly 10 the capability of developing
natural convection air flow in any orientation because, unlike
conventional corrugated fins, there is nothing to block the air
flow in the direction of the depth of the troughs, indicated by
arrows A and B. Thus, as long as fins 14 are in vertical or near
vertical planes, heat transmitted to fins 14 from pipe 12 will
generate natural convection, regardless of which parts of fins 14
are uppermost.
[0020] Straps or end portions 24, which are the portions of upper
peaks 18 and lower peaks 22 which remain after slots 20 are formed,
also serve a vital purpose. Straps 24 hold individual fins 14
together to form fin assembly 10 so that fin assembly 10 can be
handled as a single unit. Furthermore, straps 24 maintain the fin
to fin spacing originally designed into the assembly.
[0021] FIG. 1 also depicts one of a plurality of split collars 16,
which are a preferred structure for holding fin assembly 10 onto
pipe 12. Split collars 16 are formed in each fin 14, and are
substantially coaxial to one another. Split collars 16 are
pre-formed through the surface of each fin 14 as a central hole 32
and a cruciform slit 34. In this way, when pipe 12 is forced
through holes 32, radiating cruciform slits 34 deform outwardly so
as to create a plurality of gripping fingers 37. A concentric
radial pattern or plurality of preformed score lines or thinning of
the material separating the slits in cruciform slit 34, provide
preferred bend-lines 38 in the material. Bend-lines 38 are
positioned radially outwardly from central hole 32 so as to create
a preferred and uniform bending point for the gripping fingers so
that they are substantially the same length and therefore exert
approximately the same gripping force on pipe 12. As shown in FIG.
2, slots 20 are cut from sheet 30 before sheet 30 is folded to form
corrugated fin assembly 10. Also before the folding operation,
co-linear holes 32 are formed in sheet 30, and cruciform slits 34
are cut into sheet 30 so as to radiate from holes 32. Slots 20,
holes 32, and cruciform slits 34 are all located on sheet 30 so
that after sheet 30 is folded, slots 20 will be at the peaks of the
corrugations and collars 16 will all be aligned with one another
(FIG. 1).
[0022] Collars 16 are formed from holes 32 and slits 34. Collars 16
can either be preformed into sheet 30 by drawing the collars before
sheet 30 is folded or, with properly selected materials and
dimensions, after folding. If formed after folding, a mandrel or
pipe can be pushed through holes 32 to form collars 16 by deforming
gripping fingers 37 outwardly, in the same direction as the
movement of the mandrel or pipe. In either case, holes 32 are sized
so that when pipe 12 is installed it will merely require being
pushed through collars 16. Preferably, when pushing pipe 12 through
holes 32, tooling is positioned in the troughs between adjacent
fins (e.g., a comb-like fixture) to provide support for the fin
during the insertion and movement of pipe 12 through the fin.
Significantly, with pipe 12 installed, split collars 16, via
gripping fingers 37, will retain enough elasticity to hold pipe 12
with sufficient contact force to provide adequate, thermally
conductive contact.
[0023] Referring to FIG. 3, an alternative fin structure 40
comprises a plurality of fins 14 comprising an open-ended slot 44
and an opening 46 defined through each fin. Open-ended slots 44 and
openings 46 are preferably centrally located within each fin 14,
and are arranged in substantially aligned relationship to one
another from fin to fin. In this way, plurality of open-ended slots
44 and openings 46 form a receptacle-passageway through fin
structure 40. Open-ended slots 44 are sized so as to be the same or
somewhat larger than the outer diameter of a pipe 42, and openings
46 are sized so as to be the same or somewhat narrower than the
outer diameter of a pipe 42. Thus, when pipe 42 is inserted into
the receptacle-passageway formed by open-ended slots 44, it is
retained in fin structure 40 via a press fit in openings 46.
Alternatively, pipe 42 may be maintained within open-ended slots 44
be soldering, brazing, or thermal adhesives. Also, more than one
pipe 42 may be positioned within open-ended slots 44.
[0024] Of course, open-ended slots 44 and openings 46 may have a
variety of shapes, sizes and locations in fin structure 40. For
example, open-ended slots 44 may be defined by tapering edges of
each fin 14. Openings 46 may be defined by substantially circular,
elliptical, polygonal or rectilinear edges of each fin 14. The
location within fins 14 of openings 46, and the length, width, and
orientation of open-ended slots 44 may also vary as required for a
particular application without departing from the scope of the
invention. Furthermore, fin structure 40 may comprise only
open-ended slots 44.
[0025] The present invention provides a versatile cooling fin
structure which is not restricted in its orientation for convection
cooling, and which can easily be
* * * * *