U.S. patent application number 12/834660 was filed with the patent office on 2011-07-21 for reflare tool and process.
This patent application is currently assigned to Lennox Industries Inc.. Invention is credited to Randy D. Smith, Roger W. Vreeland, Donald N. Zimmer.
Application Number | 20110174048 12/834660 |
Document ID | / |
Family ID | 43827410 |
Filed Date | 2011-07-21 |
United States Patent
Application |
20110174048 |
Kind Code |
A1 |
Zimmer; Donald N. ; et
al. |
July 21, 2011 |
REFLARE TOOL AND PROCESS
Abstract
A flaring body has first and second opposing ends. A perimeter
surface intersects the first end, and a flaring surface is located
between the perimeter surface and the second end. The perimeter
surface has a first cross-sectional profile with a first area, and
the flaring surface having a second cross-sectional profile with a
second area less than the first area. The perimeter surface and the
flaring surface are joined by an inside, rounded corner. A crimping
body has a top surface and an opposing bottom surface, and an
interior surface that forms defines a passageway that connects said
top and bottom surfaces. The interior surface has a third
cross-sectional profile with a third area larger than the first
area. The flaring body is slidably captureable in the passageway.
The interior surface further has a crimping channel that extends
along at least a portion thereof and terminates at the bottom
surface.
Inventors: |
Zimmer; Donald N.;
(Marshalltown, IA) ; Smith; Randy D.;
(Marshalltown, IA) ; Vreeland; Roger W.;
(Marshalltown, IA) |
Assignee: |
Lennox Industries Inc.
Richardson
TX
|
Family ID: |
43827410 |
Appl. No.: |
12/834660 |
Filed: |
July 12, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61295501 |
Jan 15, 2010 |
|
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|
Current U.S.
Class: |
72/372 ; 72/411;
76/107.1 |
Current CPC
Class: |
B21D 39/032 20130101;
B21D 39/02 20130101; B21D 19/08 20130101; B21D 41/026 20130101 |
Class at
Publication: |
72/372 ; 72/411;
76/107.1 |
International
Class: |
B21D 31/00 20060101
B21D031/00; B21K 5/20 20060101 B21K005/20 |
Claims
1. A reflare tool comprising: a flaring body having a first end, a
second opposing end, a perimeter surface that intersects said first
end, and a flaring surface located between said perimeter surface
and said second end, said perimeter surface having a first
cross-sectional profile with a first area, and said flaring surface
having a second cross-sectional profile with a second area less
than said first area, said perimeter surface and said flaring
surface being joined by an inside, rounded corner; and a crimping
body having a top surface, an opposing bottom surface, and an
interior surface that defines a passageway that connects said top
and bottom surfaces and has a third cross-sectional profile with a
third area larger than said first area such that said flaring body
is slidably captureable in said passageway, said interior surface
further having a crimping channel extending along at least a
portion thereof and terminating at said bottom surface.
2. The reflare tool as recited in claim 1, wherein said second
cross-sectional profile includes one or more notches.
3. The reflare tool as recited in claim 1, wherein said crimping
channel has a cross-sectional profile that is about circular.
4. The reflare tool as recited in claim 1, further comprising a
source of a force applied to said first end that is able to apply a
first force to said flaring body during said flaring and a
different second force to said flaring body during said
crimping.
5. The reflare tool as recited in claim 1, wherein said crimping
channel includes a sloped channel sidewall.
6. The reflare tool as recited in claim 1, wherein said crimping
body and said flaring body are formed from hardened tool steel.
7. The reflare tool as recited in claim 1, wherein said passageway
includes a keyed portion.
8. A method of forming a reflare tool, comprising: forming a
flaring body having a first end, a second opposing end, a perimeter
surface that intersects said first end, and a flaring surface
located between said perimeter surface and said second end, said
perimeter surface having a first cross-sectional profile with a
first area, and said flaring surface having a second
cross-sectional profile with a second area less than said first
area; forming an inside, rounded corner between said perimeter
surface and said flaring surface; forming a crimping body having a
top surface, an opposing bottom surface, and an interior surface
that defines a passageway that connects said top and bottom
surfaces and has a third cross-sectional profile with a third area
larger than said first area such that said flaring body is slidably
captureable in said passageway; and forming a crimping channel
extending along at least a portion of said interior surface of said
crimping body, and terminating at said bottom surface of said
crimping body.
9. The method as recited in claim 8, wherein said second
cross-sectional profile is about circular.
10. The method as recited in claim 8, wherein said crimping channel
has a cross-sectional profile that is about circular.
11. The method as recited in claim 8, further comprising coupling
to said flaring body a source of a first force, and coupling to
said crimping body a source of a second force, wherein said first
force can be applied independently of said first force.
12. The method as recited in claim 8, wherein said passageway
includes a keyed portion.
13. The method as recited in claim 8, further comprising forming
said crimping body and said flaring body from tool steel.
14. The method as recited in claim 8, further comprising forming
said crimping channel with a sloped sidewall.
15. A method of operating a reflare tool, comprising: providing a
port ring and a joint flange located within said port ring; flaring
said joint flange by applying a first force to a first end of a
flaring body having a second end opposing said first end, a
perimeter surface that intersects said first end, and a flaring
surface located between said perimeter surface and said second end,
said perimeter surface having a first cross-sectional profile with
a first area, and said flaring surface having a second
cross-sectional profile with a second area less than said first
area, said perimeter surface and said flaring surface being joined
by an inside, rounded corner; and crimping said joint flange to
said port ring by applying a second force to a top surface of a
crimping body having an interior surface that defines a passageway
connecting said top surface to an opposing bottom surface, said
interior surface having a third cross-sectional profile with a
third area larger than said first area such that said flaring body
is slidably captureable in said passageway, said interior surface
further having a crimping channel extending along at least a
portion thereof and terminating at said bottom surface.
16. The method as recited in claim 15, further comprising
compressing said joint flange and said port ring between said
flaring surface and a channel sidewall of said crimping
channel.
17. The method as recited in claim 15, wherein said second
cross-sectional area is about circular.
18. The method as recited in claim 15, further comprising applying
a first value of said first force to said flaring body during said
flaring and a different second value of said first force to said
flaring body during said crimping.
19. The method as recited in claim 15, wherein a flare-crimp joint
formed by said flaring and crimping is sealant-free.
20. The method as recited in claim 15, wherein said joint flange is
a portion of a furnace heat exchanger.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 61/295,501, filed by Shailesh S. Manohar, et
al., on Jan. 15, 2010, entitled "An Improved Heating Furnace for a
HVAC System", and incorporated herein by reference in its entirety.
This application is related to U.S. application Ser. No. XX/XXX,XXX
(attorney docket number P070075), filed by Donald N. Zimmer, et al.
on ______, entitled "Heat Exchanger Expanded Overlap Joint",
commonly assigned with this application and incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present disclosure is directed in general to metal
working, and more specifically, to metal joining.
BACKGROUND
[0003] In some metal joining applications, a sheet metal flange is
fastened to a port located in a panel or bulkhead. In some of these
applications, the flange is formed of two halves, e.g. a clamshell,
that have been formed separately and then joined. One flange half
is typically abutted against the other flange half. If the flange
is fastened to the port by flaring the flange, a gap typically
forms between the flange halves. In some applications the resulting
gap must be sealed to prevent leakage at the joint. The sealed gap
may fail to prevent leakage when a sealant ages.
SUMMARY
[0004] In one aspect, the disclosure provides a reflare tool that
includes a flaring body and a crimping body. The flaring body has a
first end and a second opposing end. A perimeter surface intersects
the first end, and a flaring surface is located between the
perimeter surface and the second end. The perimeter surface has a
first cross-sectional profile with a first area. The flaring
surface has a second cross-sectional profile with a second area
less than the first area. The perimeter surface and the flaring
surface are joined by an inside, rounded corner. The crimping body
has a top surface and an opposing bottom surface. An interior
surface defines a passageway that connects the top and bottom
surfaces, and has a third cross-sectional profile with a third area
larger than the first area such that the flaring body is slidably
captureable in the passageway. The interior surface further has a
crimping channel extending along at least a portion thereof and
terminating at the bottom surface.
[0005] In another aspect, a method is provided for forming a
reflare tool. A flaring body is formed that has a first end and a
second opposing end. A perimeter surface intersects the first end,
and a flaring surface is located between the perimeter surface and
the second end. The perimeter surface has a first cross-sectional
profile with a first area. The flaring surface has a second
cross-sectional profile with a second area less than the first
area. An inside, rounded corner is formed between the perimeter
surface and the flaring surface. A crimping body is formed that has
a top surface and an opposing bottom surface. The crimping body
includes an interior surface that defines a passageway that
connects the top and bottom surfaces. The passageway has a third
cross-sectional profile with a third area larger than the first
area such that the flaring body is slidably captureable in the
passageway. A crimping channel is formed that extends along at
least a portion of the interior surface of the crimping body. The
crimping channel terminates at the bottom surface of the crimping
body.
[0006] In yet another aspect, a method of operating a reflare tool
is provided. The method includes providing a port ring and a joint
flange located within the port ring. The joint flange is flared by
applying a first force to a first end of a flaring body having a
second end opposing the first end. The flaring body includes a
perimeter surface that intersects the first end, and a flaring
surface located between the perimeter surface and the second end.
The perimeter surface has a first cross-sectional profile with a
first area. The flaring surface has a second cross-sectional
profile with a second area less than the first area. The perimeter
surface and the flaring surface are joined by an inside, rounded
corner. The joint flange is crimped to the port ring by applying a
second force to a top surface of a crimping body that has an
opposing bottom surface. An interior surface defines a passageway
connecting the top surface to the bottom surface. The interior
surface has a third cross-sectional profile with a third area
larger than the first area such that the flaring body is slidably
captureable in the passageway. The interior surface also has a
crimping channel extending along at least a portion thereof and
terminating at the bottom surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Reference is now made to the following descriptions taken in
conjunction with the accompanying drawings, in which:
[0008] FIGS. 1A-1D illustrates a panel port, a flange and a
flare-crimp seal of the disclosure;
[0009] FIGS. 2A and 2B illustrate various aspects of a reflare tool
of the disclosure, where FIG. 2A illustrates a flaring body and
FIG. 2B illustrates a crimping body;
[0010] FIGS. 2C, 2D-1, 2D-2, 2E-1 and 2E-2 illustrate various
alternate embodiments of the reflare tool of FIGS. 2A and 2B;
[0011] FIG. 3 presents a detail view of an inside rounded corner of
the flaring body of FIG. 2A;
[0012] FIG. 4 illustrates a detail view of a crimping channel of
the crimping body of FIG. 2B;
[0013] FIGS. 5 and 6 respectively present a method of forming and
using a reflare tool, such as the reflare tool of FIGS. 2A and
2B;
[0014] FIGS. 7-9 illustrate operation of the flaring body and the
crimping body of FIGS. 2A and 2B;
[0015] FIG. 10 illustrates a detail view of a flare-crimp joint
during formation thereof; and
[0016] FIGS. 11-16 illustrate various aspects of an illustrative an
embodiment in which a flare-crimp joint attaches a heat exchanger
to a furnace vest panel according to various aspects of the
disclosure.
DETAILED DESCRIPTION
[0017] Conventional fastening of crimped flange joints suffers from
several significant deficiencies. Conventional crimping processes
typically use several moving parts, adding complexity to the
tooling and cost to the joining operation, and increasing the
possibility of future failure of the joint. In some cases, such as
when the crimped flange is a portion of a heat exchanger for a
furnace or similar applications, exhaust gases produced by
combustion of heating fuel may leak from a compromised conventional
joint, creating a health or other risk to occupants of a heated
building, e.g. For at least these reasons, a joint and joint
crimping process is needed that reduces cost and increases
reliability of the joint.
[0018] To address such deficiencies of conventional practice, the
present disclosure describes novel and innovative embodiments of a
flare-crimp joint between a flange and a panel port, a reflare tool
to form the flare-crimp joint, and a method of forming the
flare-crimp joint. Embodiments of the disclosure overcome the
deficiencies of conventional practice in part by flaring and
crimping the flange in a two-step operation that provides a
metal-on-metal seal that remains leak-free. In some embodiments the
seal flange includes overlapping flange halves that form a seam
when flared and crimped by the disclosed flare and crimp tool. Such
embodiments result in lower cost, greater manufacturing efficiency,
and increased reliability and safety of flange seals.
[0019] Referring initially to FIGS. 1A-1D, illustrated is a panel
110 (FIG. 1A) having a port 120, and a conduit 130 (FIG. 1B) having
a port flange 140. The conduit 130 may channel, e.g., a gas or a
liquid to or from the port 120. In one embodiment the conduit is a
furnace heat exchanger, as briefly described below and described in
greater detail in co-pending U.S. patent application Ser. No.
XX/XXX,XXX (attorney docket P070075) (the 'XXX application).
[0020] FIG. 1A presents a sectional and a plan view of the panel
110. The port 120 includes a port ring 150 having a height H.sub.R.
FIG. 1B presents a sectional and a plan view of the conduit 130.
The port flange 140 has a height H.sub.F greater than H.sub.R. The
port 120 has an inside diameter larger than an outside diameter of
the port flange 140 so that the port flange 140 is receivable
within the port 120. FIG. 1C illustrates the port flange 140
located within the port 120. An extending portion 160 of the port
flange 140, having a height H.sub.F-H.sub.R, extends beyond the
port 120. The extending portion 160 is formed into a flare-crimp
seal 170 (FIG. 1D) with the port ring 150 according to embodiments
described below.
[0021] Turning to FIGS. 2A and 2B, illustrated is a reflare tool
210 of the disclosure that may be used to form the flare-crimp seal
170. The reflare tool 210 includes a flaring body 220 (FIG. 2A) and
a crimping body 230 (FIG. 2B). The flaring body 220 and the
crimping body 230 may each be formed of any material having
sufficient mechanical strength to perform flare and crimp
operations described below. In a non-limiting example, the flaring
body 220 and the crimping body 230 are formed of tool steel.
[0022] Referring to FIG. 2A, an axis 225 defines an axis of travel
during operation of the flaring body 220 relative to the crimping
body 230. The flaring body 220 has a first end 235, a second
opposing end 240, and a perimeter surface 242 therebetween that
intersects the first end 235. By "intersects", it is meant that the
first end 235 and the perimeter surface 242 meet via a corner that
may be sharp, rounded or chamfered, or the equivalent of such a
corner. A flaring surface 245 is located between and joins the
perimeter surface 242 to the second end 240. The perimeter surface
has a first cross-sectional profile 250 that has a first area. The
second end 240 has a second cross-sectional profile 255 that is
about circular and has a second area less than the first area. The
profile 255 may include on or more notches, as described below, and
still be regarded as about circular. An inside, rounded corner 246
joins the flaring surface 245 to the perimeter surface 242.
Optionally, the corner formed by the second end 240 and the flaring
surface 245 may be broken by a chamfer 247.
[0023] The crimping body 230 (FIG. 2B) has a top surface 232, an
opposing bottom surface 285 and an interior surface 260 that
defines a passageway 270 that connects the top and bottom surfaces
232, 285. The passageway 270 has an axis 275 parallel to the
direction of travel of the flaring body 220 therein, and a
cross-sectional profile 277 that is the same shape as the first
cross-sectional profile 250, but larger by a clearance for the
flaring body 220, e.g. about 50-100 .mu.m. The flaring body 220 is
thereby slidably captureable in the passageway 270. The interior
surface 260 has a crimping channel 280 with a channel sidewall 282
extending along at least a portion thereof that terminates at the
bottom surface 285 of the crimping body 230. The crimping channel
280 typically has a cross-sectional profile with the same shape as
the profile 255. However, the crimping channel 280 profile is
larger than the profile 255 to create a space between the flaring
surface 245 and the channel sidewall 282 when these surfaces are
brought adjacent to each other. Thus, in the illustrated embodiment
the cross-sectional profile of the passageway 270 at the crimping
channel 280 is also about round. Optionally, the crimping channel
280 widens into an outside rounded corner 290 at the bottom surface
285.
[0024] It is noted that while the profiles 250, 277 are circular in
the illustrated embodiment, these profiles may in general be
arbitrary as long as the flaring body 220 is slidably captureable
within the passageway 270. For example, the passageway 270 may
include a keyed portion, or the profiles 255, 277 may be
elliptical. FIG. 2C illustrates an example of a cross-section of
the crimping body 230 with the passageway 270 having a keyed
profile 292. The profile 292 is but one of many shapes that may be
used in a keyed portion. When the passageway 270 includes a keyed
portion, the flaring body 220 will typically have a complementary
profile to the keyed portion.
[0025] While the port 120 and the port flange 140 are illustrated
as being about circular, other shapes are within the scope of the
disclosure, including oval, elliptical, square, triangular, etc. In
some cases, it may be desirable to form the flare-crimp seal 170
without any gaps or breaks in the seal to ensure no leakage to or
from the conduit 130. Such a seal is described in the 'XXX
application (docket number P070075). In such cases, it is expected
that a round or elliptical port 120 and port flange 140 will be
more able than an opening with sharp corners to accommodate the
stresses produced by the flare-crimp operation without compromising
the seal formed by the port flange 140.
[0026] The cross-sectional profile of the flaring body 220 taken at
the flaring surface 245 will typically be the same shape as the
port 120 and the port flange 140. For example, FIG. 2D-1
illustrates an elliptical profile 294 of the flaring body 220 at
the flaring surface 245, which would be advantageous when the port
120 and the port flange 140 are elliptical. Similarly, FIG. 2D-2
illustrates a profile 295 of the passageway 270 taken through the
channel sidewall 282 may be elliptical when the port 120 and the
port flange 140 are elliptical. Of course, other shapes may be used
for the port 120 and the port flange 140, with the flaring body 220
and the passageway 270 being configured accordingly at the crimping
channel 280.
[0027] FIG. 3 illustrates aspects of the flaring body 220. In the
illustrated embodiment, the curvature of the inside rounded corner
246 is approximated by a circle with radius 310. As described
further below, the radius 310 is selected to smoothly deform the
extending portion 160 away from the port 120 during a flare-crimp
operation. In general, the radius 310 may be selected taking into
account mechanical and material factors related to the port flange
140, such as stiffness and malleability. In a nonlimiting
embodiment, a radius of about 3.2 mm (.apprxeq.0.125'') may be used
when the flange is formed of aluminized type 1 steel sheet with a
thickness in a range of about 0.6 mm to about 0.8 mm
(.apprxeq.20-22 ga or .apprxeq.0.024-0.032''). Also illustrated in
FIG. 3 is an angle .theta..sub.1 between the axis 225 and the
flaring surface 245. The flaring surface 245 optionally may be
sloped (.theta..sub.1>0) to provide some flaring of the
extending portion 160 as the flaring body 220 enters the port
flange 140, as described further below. In a nonlimiting
embodiment, .theta..sub.1 ranges from about 0.degree. to about
5.degree., with about 2.5.degree. being preferred.
[0028] FIG. 4 illustrates aspects of the crimping channel 280. The
channel sidewall 282 is characterized by an angle .theta..sub.2
relative to the axis 275. Optionally .theta..sub.2 may have a value
greater than zero. For example, the .theta..sub.2 may be selected
to reduce binding between the channel sidewall 282 and the flange
140, and/or to produce a desired pressure on the flare-crimp seal
170 during the flare-crimp operation, as described further below.
In a nonlimiting embodiment, .theta..sub.2 ranges a value in a
range from about 1.degree. to about 10.degree.. In some cases, a
value in a range from about 5.degree. to about to about 8.degree.
is preferred, and a value of about 7.5.degree. is more
preferred.
[0029] FIG. 5 presents a method generally designated 500 of forming
a reflare tool. The method 500 is described with reference to the
reflare tool 210, without limitation to the illustrated embodiment
thereof. The method 500 begins in a step 510, in which the flaring
body 220 is formed. The flaring body 220 may be formed using
conventional tool-forming techniques, including, e.g., lathing,
milling, heating and quenching. The flaring body 220 may be formed,
e.g., from a conventional material such as W-1 tool steel. The
previously described features of the flaring body 230 are formed,
including the first end 235, the second opposing end 240, and the
perimeter surface 242 located therebetween. In a step 520, the
inside, rounded corner 246 is formed between the perimeter surface
242 and the second opposing end 240.
[0030] In a step 530, the crimping body 230 is formed. Again, the
crimping body 230 may be formed using conventional tool materials
and methods. The previously described features of the crimping body
230 are formed, including the passageway 270 in which the flaring
body 220 is slideably capturable. In a step 540, the crimping
channel 280 is formed. Optionally, the outside rounded corner 290
is formed.
[0031] FIG. 6 presents a method generally designated 600 of
operating a reflare tool, such as the reflare tool 210 including
the flaring body 220 and the crimping body 230. The method 600 is
described with concurrent reference to FIGS. 7-10, which illustrate
operation of the reflare tool 210 in one nonlimiting embodiment of
the disclosure. The method 600 is described with reference to
elements of FIGS. 1A-1D, 2A-2B, 3 and 4 without limitation to the
embodiments illustrated therein. Those of ordinary skill in the
pertinent art will recognize that the reflare tool 210 may be
operated to join any parts that include features functionally
similar to the port ring 150 and the port flange 140.
[0032] Referring to FIG. 6 initially, in a first step 610 the port
ring 150 is provided with the port flange 140 located therein. As
used herein and in the claims, "provided" means that an item being
provided may be manufactured by the individual or business entity
performing the disclosed methods, or obtained thereby from a source
other than the individual or entity, including another individual
or business entity.
[0033] In a step 620, the flaring body 220 flares the port flange
140. FIG. 7 illustrates an initial configuration of the flaring
body 220, the crimping body 230, the port flange 140 and the port
ring 150. The flaring body 220 may be initially located as
illustrated such that the port flange 140 contacts the inside
rounded corner 246. A backing plate 710 may provide support to the
panel 110 and the conduit 130 during crimping and flaring. The
crimping body 230 may be located such that the bottom surface 285
does not obstruct the port flange 140 as the port flange 140 is
flared. (See FIG. 8, e.g.) To ensure no obstruction occurs, in the
illustrated embodiment the bottom surface 285 is placed at a
distance D from the port flange 140 that may be, e.g., a few
millimeters. In FIG. 8, a force F.sub.1 from a force-producing
source (e.g., a hydraulic piston) is applied to the flaring body
220, causing the port inside rounded corner 246 to deform the
flange 140 away from the flaring body 220. The inside rounded
corner 246 eases the deformation of the port flange 140 by, e.g.,
distributing the deformation forces over a greater time and
distance.
[0034] In a step 630, the crimping body 230 crimps the port flange
140 to the port ring 150. Referring to FIG. 9, a force F.sub.2 is
applied to the crimping body 230. The crimping body 230 moves in
response to the force F.sub.2 to capture the flared portion of the
port flange 140 in the crimping channel 280. The force F.sub.2 may
be applied independently of the force F.sub.1.
[0035] Referring to FIG. 10, the channel sidewall 282, the flaring
surface 245 and the inside rounded corner 246 cooperate to
constrain the volume of the port ring 150 and the port flange 140
in a high-pressure zone 1010. In the zone 1010, a distance W
between the channel sidewall 282 and the flaring surface 245 is
less than the sum of the original thicknesses of the metal layers
therein. Thus, when the crimping body 230 is forced over the port
ring 150, the resulting pressure on the port flange 140 and the
port ring 150 may cause a metallurgical bond to form therebetween.
The metallurgical bond is expected to provide a robust seal to
prevent leakage into or out of the conduit 130 at the location of
the flare-crimp seal 170.
[0036] Referring back to FIGS. 6 and 9, in an optional step 640 a
third force F.sub.3 that may be different from F.sub.2 is
maintained on the flaring body 220 while the force F.sub.2 is
applied to the crimping body 230. In this manner, the pressure
within the zone 1010 may be controlled to a greater extent than
would otherwise be the case, providing an additional means to
determine the characteristics of the flare-crimp seal 170.
[0037] Turning now to FIGS. 11-16, illustrated are aspects of an
example embodiment of forming a flare-crimp seal using a reflare
tool of the disclosure, such as the reflare tool 210. Those of
ordinary skill in the pertinent art will recognize that the
demonstrated principles may be applied to other embodiments within
the scope of the disclosure.
[0038] Referring initially to FIG. 11, in the illustrated
embodiment a furnace heat exchanger 1110 includes flanges 1120 at
ends of a serpentine conduit 1130 that carries hot gases produced
by combustion of a heating fuel. In other embodiments the heat
exchanger 1110 may not be serpentine, such as a "U" shaped heat
exchanger. The heat exchanger 1110 may be formed, e.g., by joining
two halves of a stamped-metal clamshell assembly by a crimping
process that forms crimp seals 1140. A crimp-flare seal may be
formed to join the heat exchanger 1110 to a furnace vest panel or a
collector box panel, e.g.
[0039] FIG. 12 illustrates a sectional view of a first heat
exchanger half 1210 (FIG. 12A) and a second heat exchanger half
1220 (FIG. 12B) taken through respective flange halves 1230, 1240.
The two halves 1210, 1220 are joined to form the heat exchanger
1110 and the flange 1120. FIG. 12C illustrates a section taken
through the flange 1120, illustrating overlap of the flange half
1230 by the flange half 1240.
[0040] FIG. 13 illustrates aspects of the flange 1120 in greater
detail. The flange 1120 includes overlap regions 1310 in which
capturing tabs 1320 overlap terminating portions 1330. FIG. 14
shows a panel port 1410 in a panel 1420 configured to receive the
flange 1120. The port 1410 includes a port ring 1430, and notches
1440 configured to receive the overlap regions 1310.
[0041] Conventionally, a joint formed between a furnace heat
exchanger and a panel port may present a risk of leakage of exhaust
gases from the joint. Typically, two heat exchanger halves are
joined such that two flange halves form butt joints where they
meet. When the assembled flange is fastened to the panel port, the
butt joints typically spread to form a gap. To ensure that exhaust
does not leak from the joint, a sealant is typically used, adding
to assembly cost and reducing reliability of the joint.
[0042] In embodiments represented by the flange 1120 and the port
1410, the overlap region 1310 forms a robust seal when the flange
1120 is joined to the port ring 1430 using a reflare tool of the
disclosure, e.g. the reflare tool 210. Using an assembly method of
the disclosure, e.g. the method 600, the flange 1120 is first
flared by the flaring body 220, and then crimped to the port ring
1430 by the crimping body 230. The length of the overlap region
1310 may be determined to provide sufficient overlap between the
flange halves 1230, 1240 in the overlap region such that no gap
forms therebetween when the flange 1120 is flared and crimped.
Pressure in the zone 1010 produced by the force F.sub.1 acting on
the flaring surface 245 (FIG. 2A) and the channel sidewall 282
(FIG. 2B) is thought to increase friction between the flange halves
1230, 1240, further reducing relative movement of the capturing
tabs 1320 and the terminating portions 1330 that might otherwise
cause a gap to form. The pressure is further thought to form a
metallurgical bond between the flange halves 1230, 1240 that
ensures no leakage to or from the conduit 1130. Additional details
are described in the 'XXX application (docket number P070075).
[0043] In some cases, it may be advantageous to limit the pressure
formed at the overlap regions 1310 during the flaring and crimping
operations. In such cases the flaring body 220 and the crimping
body 230 may include notches at positions corresponding to the
location of the overlap regions 1310. Referring to FIG. 2E-1, a
cross-sectional profile 296 of the flaring body 220 taken through
the flaring surface 245 (FIG. 2A) may include one or more notches
297 corresponding to each overlap region 1310. Similarly, FIG. 2E-2
illustrates a cross-sectional profile 298 of the crimping body 230
taken through the channel sidewall 282 (FIG. 2B) may include one or
more notches 299 to accommodate the overlap regions 1310.
[0044] FIGS. 15A and 15B illustrate two sections as indicated in
FIG. 14 through a flare-crimp joint 1510 formed from the flange
1120. In FIG. 15A, the joint 1510 includes, in addition to the port
ring 1430, the capturing tabs 1320 of the outer flange half 1240
and the terminating portions 1330 of the inner flange half 1230.
Thus, the joint 1510 includes two metal layers over the port ring
1430 in this sectional view. In FIG. 15B, the flare-crimp joint
1510 includes, in addition to the port ring 1430, only the inner
flange half 1230 and the outer flange half 1240. To accommodate the
extra thickness of the metal layers in the view of FIG. 15A, the
flaring body 220 and/or the crimping body 230 respectively include
the notches 297, 299 as previously described. The flare-crimp joint
1510 may be sealant-free, meaning that no sealant is needed to
prevent leakage of gases to or from the conduit 1130.
[0045] FIG. 16 illustrates a photograph of a nonlimiting embodiment
of a vest panel 1605 to which a heat exchanger is joined by a
flare-crimp joint 1610 as formed using a method within the scope of
the disclosure. The port flange 1120 has an outside diameter of
about 2.5 cm (.about.1''), and a height H.sub.F of about 10 mm
(.about.0.4''). The port ring 1430 has a height H.sub.R of about 5
mm (.about.0.2'') and a thickness of about 0.75 mm
(.about.0.029''). Under the conditions of this example, the
flare-crimp joint 1610 may be formed using the reflare tool 210,
wherein the force F.sub.1 is about 1.56E4 N (about 3500 lbs), and
the force F.sub.2 is about 7.56E3 N (about 1700 lbs).
[0046] Notably, the flare-crimp joint 1610 smoothly transitions
from single-layer portions 1620, 1630 to double-layer portions
(seams) 1640, 1650 that include two metal layers, e.g., the
capturing tab 1320 and the terminating portion 1330.
Advantageously, and in contrast to conventional practice, the
flare-crimp joint 1610 does not include any sealant, and none is
necessary. The flare-crimp joint 1610 forms a tight seal with the
vest panel 1605, preventing leakage of exhaust gases, and obviating
the need for any sealant.
[0047] Those skilled in the art to which this application relates
will appreciate that other and further additions, deletions,
substitutions and modifications may be made to the described
embodiments.
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