U.S. patent application number 13/029242 was filed with the patent office on 2012-08-23 for brazing joints.
Invention is credited to Dae-Hyun Jin.
Application Number | 20120211208 13/029242 |
Document ID | / |
Family ID | 46651789 |
Filed Date | 2012-08-23 |
United States Patent
Application |
20120211208 |
Kind Code |
A1 |
Jin; Dae-Hyun |
August 23, 2012 |
BRAZING JOINTS
Abstract
One aspect provides a header tube and a refrigeration tube that
have ends on which one or more coupling ends are integrally formed
thereon. Methods of fabricating the header tube and refrigeration
tube are also provided.
Inventors: |
Jin; Dae-Hyun; (Grenada,
MS) |
Family ID: |
46651789 |
Appl. No.: |
13/029242 |
Filed: |
February 17, 2011 |
Current U.S.
Class: |
165/173 ;
29/890.03; 29/890.052 |
Current CPC
Class: |
F28F 9/182 20130101;
F28D 1/0475 20130101; Y10T 29/49389 20150115; F28F 9/0243 20130101;
F28F 9/26 20130101; Y10T 29/4935 20150115; B21D 39/04 20130101;
B21D 53/06 20130101 |
Class at
Publication: |
165/173 ;
29/890.03; 29/890.052 |
International
Class: |
F28F 9/02 20060101
F28F009/02; B21D 53/06 20060101 B21D053/06 |
Claims
1. A refrigerant coil, comprising: a header tube, said header tube
having an integrally formed coupling end, said coupling end having
a first non-flared section at an end of said header tube joined by
a tapered shoulder to a second non-flared section wherein an
internal diameter of said first section is less than an internal
diameter of said second section.
2. The refrigerant coil recited in claim 1, wherein a ratio of said
internal diameter of said first section to said internal diameter
of said second section is less than 1.
3. The refrigerant coil recited in claim 2, wherein said ratio is
about 0.97.
4. The refrigerant coil recited in claim 1, wherein said coupling
end comprises aluminum and further comprising a copper connecting
tube having an end positioned within said coupling end, said copper
connecting tube having an external diameter that is less than said
internal diameter of said first section and said internal diameter
of said second section and wherein said copper connecting tube
seats on an internal shoulder of said first section at a junction
point of said header tube and said coupling end.
5. The refrigerant coil recited in claim 4, wherein a brazing
solder is located only between said external diameter of said
copper connecting tube and said internal diameter of said second
section.
6. The refrigerant coil recited in claim 4, wherein a difference
between said internal diameter of said first section and said
external diameter of said connecting tube ranges from about 0.002''
to about 0.006''.
7. A method of manufacturing a refrigerant coil, comprising:
cutting a refrigerant header tube to a predetermined length having
first and second ends; and shaping at least one of said first and
second ends to form a coupling end, said coupling end having first
and second non-flared sections joined by a tapered shoulder wherein
an internal diameter of said first section is less than an internal
diameter of said second section.
8. The method recited in claim 7, wherein shaping includes shaping
said internal diameter of said first section and said internal
diameter said second section such that a ratio of said internal
diameter of said first section to said internal diameter of said
second section is less than 1.
9. The method recited in claim 8, wherein said ratio is about
0.97.
10. The method recited in claim 7, wherein said coupling ends
comprise aluminum and said method further comprising, positioning
an end of a connecting tube comprising copper within said coupling
end such that said connecting tube seats on an internal should of
said first section, said connecting tube having an external
diameter that is less than said internal diameter of said first
section and said internal diameter of said second section; and
brazing said connecting tube to said coupling end such that brazing
solder is located only between said external diameter of said
connecting tube and said internal diameter of said second
section.
11. A refrigeration coil, comprising: a refrigeration tube having
first and second longitudinal sections having a first rounded
corner located therebetween and having first and second ends,
respectively, at least one of said first and second ends comprising
an integrally formed coupling end having: a first flared section
located adjacent said first end and having a first internal
diameter that graduates from a first, smaller internal diameter to
a second, larger internal diameter; a second non-flared section
joining said first section and having a second internal diameter
larger than said first smaller internal diameter; a third flared
section joining said second section and having a third internal
diameter that graduates from a third smaller diameter to a fourth
internal diameter that is larger than said second internal
diameter; and a header plate located adjacent said first and second
ends and wherein said first and second longitudinal sections extend
through openings located in said header plate.
12. The refrigeration coil recited in claim 11, wherein each of
said first and second ends comprises said coupling end, and further
comprising a second rounded corner that is brazed to each of said
coupling ends.
13. The refrigeration coil recited in claim 11, wherein said first
and third flared sections each include an angled wall, wherein a
ratio of said angled wall of said first flared section to said
angled wall of said third flared section ranges from about 0.71 to
about 0.90.
14. The refrigeration coil recited in claim 13, wherein said ratio
is about 0.9.
15. The refrigeration coil recited in claim 11, wherein said
refrigeration tube has a length that extends from said first
rounded corner to said coupling end, and wherein said coupling end
extends from said header plate a distance, wherein said distance
ranges from about 0.65 to about 0.75 inches.
16. The refrigeration coil recited in claim 11, wherein a
difference between the internal diameter of the non-flared section
and the external diameter of the connecting return bend ranges from
about 0.001'' to about 0.003''.
17. The refrigeration coil recited in claim 15, wherein said
distance is about 0.72 inches.
18. A method of fabricating a refrigeration coil, comprising:
forming a refrigeration tube having first and second longitudinal
sections joined by a first rounded corner, said first and second
longitudinal sections having first and second ends, respectively;
positioning said first and second ends through openings in a header
plate to a predetermined distance; shaping a coupling end on each
of said first and second ends, said coupling ends each having a
first flared section located at said first end and having a first
internal diameter that graduates from a first, smaller internal
diameter to a second, larger internal diameter, a second section
joining said first section and having a second internal diameter
larger than said first smaller internal diameter, and a third
flared section joining said second section and having a third
internal diameter that graduates from a third smaller diameter to a
fourth internal diameter that is larger than said second internal
diameter; and brazing a second rounded corner to each of said
coupling ends.
19. The method recited in claim 17, wherein shaping said first and
third flared sections includes forming an angled wall, wherein a
ratio of said angled wall of said first internal diameter to said
angled wall of said third internal diameter ranges from about 0.71
to about 0.90.
20. The method recited in claim 17, wherein said refrigeration tube
has a length extending from said first rounded corner to said
coupling ends wherein said the distance is about from 0.65 to 0.75
inches.
21. The refrigeration coil recited in claim 17, wherein a
difference between the internal diameter of the non-flared section
and the external diameter of the connecting return bend ranges from
about 0.001'' to about 0.003''.
22. The method recited in claim 20, wherein said distance is about
0.72 inches.
Description
TECHNICAL FIELD
[0001] This application is directed, in general, to a coupling end
that can be used to braze joints in heating ventilation air
conditioning (HVAC) systems.
BACKGROUND
[0002] Condensing or cooling coils are well known and have been
used for decades in HVAC systems. Some coils are constructed of
aluminum while other coils are constructed of copper. Typically,
these coils are connected to the refrigerant delivery pipes that
include brazed joints. As is well known, brazing is a metal-joining
process whereby a filler metal is heated above and distributed
between two or more close-fitting parts by capillary action. The
filler metal is brought slightly above its melting (liquidus)
temperature while protected by a suitable atmosphere, usually a
flux. It then flows over the base metal (known as wetting) and is
then cooled to join the work pieces together. However, the price of
copper metal has begun to experience a sharp increase in price due
to growing world-wide demand. As such, manufacturers have not only
been continually confronted with brazing problems in general, but
have also begun to be confronted with problems associated with
brazing two different metals, such as aluminum and copper
together.
SUMMARY
[0003] One aspect provides a refrigerant coil. In this embodiment,
the refrigerant coil comprises a header tube that has an integrally
formed coupling end. The coupling end has a first non-flared
section at an end of the header tube joined by a tapered shoulder
to a second non-flared section wherein an internal diameter of the
first section is less than an internal diameter of the second
section.
[0004] In another aspect, there is provided a a method of
manufacturing the refrigerant coil in which the method comprises
cutting a refrigerant header tube to a predetermined length to have
first and second ends and shaping at least one of said first and
second ends to form a coupling end. The coupling end has first and
second non-flared sections joined by a tapered shoulder wherein an
internal diameter of the first section is less than an internal
diameter of the second section.
[0005] In yet another embodiment, a refrigeration coil is provided.
In this embodiment, a refrigeration tube has first and second
longitudinal sections having a first rounded corner located
therebetween and has first and second ends, respectively. At least
one of the first and second ends comprises an integrally formed
coupling end having a first flared section located adjacent the
first end and having a first internal diameter that graduates from
a first, smaller internal diameter to a second, larger internal
diameter. A second non-flared section joins the first section and
has a second internal diameter larger than the first smaller
internal diameter. A third flared section joins the second section
and has a third internal diameter that graduates from a third
smaller diameter to a fourth internal diameter that is larger than
the second internal diameter. This embodiment further comprises a
header plate located adjacent the first and second ends and wherein
the first and second longitudinal sections extend through openings
located in the header plate.
[0006] A method of fabricating the refrigeration coil discussed
above is also provided. This embodiment comprises forming the
refrigeration tube to have first and second longitudinal sections
joined by a first rounded corner. The first and second longitudinal
sections have first and second ends, respectively. The first and
second ends are positioned through openings in the header plate to
a predetermined distance, and the ends are shaped to form a
coupling end on each of the first and second ends. The coupling
ends each have first flared section located at the first end and
have a first internal diameter that graduates from a first, smaller
internal diameter to a second, larger internal diameter. The second
section joins the first section and has a second internal diameter
larger than the first smaller internal diameter, and a third flared
section joins the second section and has a third internal diameter
that graduates from a third smaller diameter to a fourth internal
diameter that is larger than the second internal diameter. This
embodiment further comprises brazing a second rounded corner to
each of the coupling ends.
BRIEF DESCRIPTION
[0007] Reference is now made to the following descriptions taken in
conjunction with the accompanying drawings, in which:
[0008] FIG. 1A illustrates an embodiment of a header tube having an
integrally formed coupling end, as provided by this disclosure;
[0009] FIG. 1B illustrates the header tube of FIG. 1A coupled to a
conventional refrigeration coil;
[0010] FIG. 2 illustrates a coupling end of the header tube of FIG.
1A having a connecting tube received therein;
[0011] FIG. 3 illustrates the embodiment of FIG. 2 subsequent to a
brazing processes;
[0012] FIG. 4A-4B illustrate an embodiment of a refrigeration coil
having at least one integrally formed coupling end that extends
through a header plate;
[0013] FIG. 5 illustrates an enlarged view of an embodiment of the
coupling end of the refrigeration coil of FIG. 4;
[0014] FIG. 6 illustrates the refrigeration coil of FIG. 4 having a
return bend brazed thereto; and
[0015] FIG. 7 illustrates an enlarged view of the coupling end and
return bend of FIG. 6, subsequent to a brazing process.
DETAILED DESCRIPTION
[0016] FIG. 1A illustrates one embodiment of a refrigeration tube
100 that may be used in a conventional refrigeration coil 103, as
generally seen in FIG. 1B, including those employed in a
refrigeration or condensing coil of a HVAC system. The
refrigeration tube 100 is typically cut to a length 105, as may be
required by design. In this particular embodiment, the
refrigeration tube 100 may be a header tube to which other
refrigeration tubes may be coupled at the points of openings 110
located along its length 105. The refrigeration tube 100 also
includes an integrally formed coupling end 115 that may be located
at one or both ends of the refrigeration tube 100. These integrally
formed coupling ends 115 provide unique advantages over those of
conventional design.
[0017] For example in conventional designs, a sweat coupling collar
is typically used to join two different pieces of tubing, which
typically have the same metallic composition, such as copper. In
such applications, the collar must be brazed or soldered to the end
of each tube that is to be joined. However, problems can arise when
a copper based refrigeration coil is replaced with an aluminum base
refrigeration coil. This exchange of coil types is beginning to
happen with greater frequency given that the price of copper has
risen significantly. Thus, conventional sweat joints must first be
unsealed and then re-sweated after coils are exchanged. In such
operations, the sweat joints can be prone to leaks or weak joints
due to the characteristics of the brazing solder or the brazing
filler metal for the joint brazing between dissimilar materials
such as the connecting tube, which might be copper and the replaced
coil, which might be aluminum. Unlike brazing between similar
materials, subtle movements of dissimilar materials during brazing
affect brazing quality. Uniform and smooth distribution of filler
metal while positioning brazing materials without any movements,
especially during a cooling down period is a key for the quality
joint brazing between dissimilar materials. Therefore, a unique
design for the coupling end is necessary.
[0018] FIG. 2 illustrates an enlarged view of the coupling end 115
having a connecting tube 205 positioned within the coupling end
115. In one embodiment, the header tube 100 and integral coupling
end 115 and connecting tube 205 may be comprised of the same
material, such as aluminum or copper. However, in another
embodiment, the connecting tube 205 might be comprised of copper,
while the header tube 100 and integral coupling end 115 might be
comprised of aluminum. In this embodiment, the integral coupling
end 115 is particularly advantageous by providing a superior brazed
connection when compared to those of conventional design. For
example, in the illustrated embodiment, the coupling end 115 is
integrally formed with the refrigeration tube 100. As such, no
brazing steps need be taken to attach the coupling end 115 on the
end of the refrigeration tube 100, thereby reducing the chances of
an inferior brazed joint. Moreover, the coupling end 115 has a
first non-flared section 210 that has an internal diameter 215
which is less than an internal diameter 220 of a second non-flared
section 225, the advantages of which as discussed below. The first
section 210 and the second section 225 are joined by a shoulder
230. Also, the first section 210 is integrally formed with the
header tube 100 at shoulder 235. In contrast, certain conventional
designs have only one non-flared section or only one flared
section, which provides a much tighter gap between the tube and the
coupling end.
[0019] When positioned within the coupling end 115, the connecting
tube 205, which has an external diameter 240 that is less than both
the internal diameters 215 and 220, seats on the shoulder 235. In
one advantageous embodiment, a ratio 245 of the internal diameter
215 to the internal diameter 220 is less than 1. For example, in
one design, the internal diameter 215 may be 0.756 inches, while
the internal diameter 220 may be 0.780 inches, thereby providing a
ratio of about 0.97. The advantages of this general ratio are
addressed below regarding FIG. 3.
[0020] FIG. 3 illustrates an embodiment where the connecting tube
205 is brazed to the coupling end 115. As seen here, due to the
above-stated ratio 245 of the internal diameters 215, 225, the
brazing solder 305 is substantially located only between the
external diameter 240 of the connecting tube 205 and the internal
diameter 220 of the second section 225; that is, typically, there
is a small amount of solder located between the first section 210
and the connecting tube 205. In one embodiment, a difference
between the internal diameter 215 of the first section 210 and the
external diameter 240 of the connecting tube 205 ranges from about
0.002'' to about 0.006''. This provides a strong brazed connection
between the header tube 100 and the connecting tube 205 and
substantially isolates the solder to the area between the section
210 and the connecting tube 240. Further, the difference also
allows a close enough fit between the section 210 and the
connecting tube 205 that the connecting tube is held in a
substantially planar position, which also allows for an improved
brazed connection. Also, in one embodiment, a difference between
the internal diameter 220 of the second section 225 and the
external diameter 240 of the connecting tube 205 ranges from about
0.01'' to about 0.03''. This provides smooth and uniform
distribution of brazing solder or brazing filler metal between the
header tube 100 and the connecting tube 205 and especially between
the second section of 225 and the external diameter 240 of the
connecting tube 205. Since conventional designs typically have only
one non-flared section or only one flared section, as mentioned
above, it's very difficult, if not impossible, to meet both
requirements of a tight fit and smooth and uniform distribution at
the same time. In such conventional designs, given the decrease in
the difference between the internal diameter of the coupling end
and the external diameter of the connecting tube, it's not easy to
feed the brazing solder or the brazing filler metal smoothly and
uniformly due to the tight gap. Moreover, it's very likely, in such
conventional designs for the brazing filler to flow into the
interior of the header and it's very difficult to position the
connecting tube in a substantially planar position.
[0021] In one embodiment, the header tube 100 may be fabricated by
cutting it to a predetermined length as required by design, which
forms first and second ends. A press and die, which may have a
mirror configuration of the coupling end 115, can be used to shape
at least one of the ends of the header tube 100 to form the
integral coupling end 115, as described above in its various
embodiments.
[0022] FIG. 4A illustrates another embodiment of a refrigeration
coil as provided by this disclosure. This embodiment provides a
refrigeration tube 400 having longitudinal sections 405, 410 that
are joined by a rounded corner 415 located between them. The
rounded corner 415 may be integrally formed with the tube 400, such
as a bend in the tube, or it may be brazed onto the ends of the
longitudinal sections 405, 410. The refrigeration tube 400 has a
length 420 that extends from the rounded corner 415 to the ends
417, 419 of the longitudinal sections 405, 410, which include
integrally formed coupling ends 425, 430, as shown in FIG. 45. The
integrally formed coupling ends 425, 430 provide advantages over
conventional coupling ends that must be individually brazed onto
the ends of the tubes, which requires additional manufacturing or
assembling steps and also increases the possibility that a weak or
leaky joint may result. Though two coupling ends 425, 430 are
shown, it should be noted that, in other embodiments, only one
coupling end might be present. A press and a die having a mirror
configuration of the coupling ends 425, 430 can be used of shape
the ends 417, 419 into the coupling ends 425, 430.
[0023] The refrigeration coil further includes a header plate 435
that has openings through it and that is located adjacent the
coupling ends 425, 430. Prior to the formation of the coupling ends
425, 430, the ends 417, 419 of the longitudinal sections 405, 410
are inserted through openings in the header plate 435 to a
predetermined distance, as discussed below.
[0024] FIG. 5 illustrates an enlarged view of one of the coupling
ends 425, generally shown in FIG. 4B. In this embodiment, the
integrally formed coupling end 425 has a flared section 505 located
adjacent an end of the longitudinal section 405. The flared section
505 has an internal diameter 510 that graduates from a smaller
internal diameter 510a to a larger internal diameter 510b. The
coupling end 425 further comprises a non-flared section 515 that
joins the flared section 505 and that has an internal diameter 520
that is larger than the smaller internal diameter 510a. Another
flared section 530 joins the non-flared section 520 and also has an
internal diameter 535 that graduates from a smaller diameter 535a
to an internal diameter that is larger than the internal diameter
520.
[0025] In one embodiment, the flared sections 505 and 530 each
include an angled wall 505a and 530a, respectively, (further
designated by the arcs) wherein a ratio of the angled wall 505a of
the flared section 505 to the angled wall 530a of the flared
section 530 ranges from about 0.71 to about 0.90. In one specific
embodiment, the ratio may be 0.9. For example, the angled wall 505a
may have an angle of about 27.degree. and the angled wall 530a may
have an angle of about 30.degree.. It should be understood that
other angles may be used to achieve the range of ratios and the
specific ratio has noted above. These angles provide the benefits
over conventional devices. For example, the ratio of the angled
wall of many conventional designs is about 0.4 to about 0.6, which
means the angled wall of the conventional designs is typically much
greater than that for the embodiment illustrated in FIG. 5.
However, problems such as a buckling issue and split cups can arise
with these conventional designs when a copper based refrigeration
coil is replaced with an aluminum base refrigeration coil because
an aluminum base refrigeration coil requires much greater expansion
force because of the thicker material thickness due to the lower
tensile strength in order to maintain the required minimum internal
burst pressure. Therefore, a unique design for the coupling ends
425, 430 is needed for a lower tensile strength material such as
aluminum.
[0026] FIG. 6 illustrates the refrigeration tube 400 where another
return bend 605 has been brazed to the coupling ends 425, 430.
Conventional brazing techniques may be used to braze the return
bend 605 to the coupling ends 425, 430. As seen in this embodiment,
the coupling ends 425, 430 are formed a distance 610 from the
header plate 435. In one embodiment, the refrigeration tube has the
length 420 that extends from the rounded corner 415 to the coupling
ends 425, 430, and the coupling ends 425, 430 extend from the
header plate 435 the distance 610 is at least about 0.65 inches. In
one advantageous embodiment, the distance ranges from about from
0.65 to about 0.75 inches. The above-mentioned distance
advantageously provides greater distance between the header plate
435 and the brazing point, and thereby prevents excessive heating
of the header plate 435 and reduces the possibility of the header
plate 435 cracking due to excessive heat. Normally, aluminum header
plates are being used for aluminum base refrigeration coils.
[0027] FIG. 7, illustrate a partial view of the coupling end 425
after brazing operations have been completed to braze the return
bend 605 to the coupling end 425. As seen in this embodiment, due
to general configuration as described above, the coupling end
allows for the end of the return bend 605 (shown in dashed lines)
to tightly seat on the shoulder at the junction of the flared
section 505 and the non-flared section 515. In one embodiment, a
difference between the internal diameter 515 of the non-flared
section and the external diameter of the connecting return bend 605
ranges from about 0.001'' to about 0.003''. This tighter gap
between the coupling end 425 and the connecting return bend 605
provides advantages such as improved brazing quality, higher
brazing speed, and less damage of header plate 435 over the
conventional designs. In addition, the flared section 530 allows
solder 705 to uniformly seal about end of the coupling end 425 and
the return bend 605, thereby providing an improved brazed joint
over conventional coupling designs and processes.
[0028] A method of fabricating the refrigeration tube 400 is also
provided. In one embodiment, the method may comprise forming
longitudinal sections 405, 410 that are joined by the rounded
corner 415. Ends 417, 419 of the longitudinal sections 405, 410 are
positioned through openings in the header plate 435 to the
predetermined distance 610. The ends 417, 419 are then shaped to
form integral coupling ends 425, 430, as seen in FIG. 4. In one
method embodiment, a press and die may be used to produce coupling
ends 425, 430. Each of the coupling ends 425, 430 may be formed to
have the flared sections 505, 515, 530, as described above. Once
the coupling ends 425, 430 are formed; the round corner 605 can be
brazed or soldered in place using conventional brazing
processes.
[0029] 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.
* * * * *