Information
-
Patent Grant
-
6715202
-
Patent Number
6,715,202
-
Date Filed
Friday, November 2, 200123 years ago
-
Date Issued
Tuesday, April 6, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Bryant; David P.
- Compton; Eric
Agents
- Beres; William J.
- O'Driscoll; William
-
CPC
-
US Classifications
Field of Search
US
- 029 726
- 029 727
- 029 33 T
- 029 282
- 029 89003
- 029 890053
- 029 819
- 072 381
- 072 384
- 493 413
- 493 414
- 493 415
-
International Classifications
-
Abstract
An apparatus and method of forming serpentine heat exchanger coils from spine fin tubing involves applying spine fins to a tube while simultaneously forming the tube into a serpentine shape. The bending and fin wrapping occurs while a feed roll continues paying out the tube without interruption. Multiple bends can be made simultaneously.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to heat exchanger coils having spine fin tubing. More particularly, the present invention relates to manufacturing such a heat exchanger.
2. Description of Related Art
Some heat exchangers or coils used for transferring heat from one fluid to another comprise a tube formed into a serpentine shape. Usually a refrigerant, or some other fluid, travels through the interior of the tube, while a second fluid, such as air, passes across the tube's exterior. To enhance heat transfer between the fluids, the tube may include fins or some other heat transfer member on the exterior of the tube. Often the fins are relatively thin and delicate, thus making it difficult to form the tube into a serpentine shape without damaging the fins. The fins of spine fin tubing, as disclosed in U.S. Pat. Nos. 3,005,253; 3,134,166; 3,160,129; and 3,688,375 (all of which are specifically incorporated by reference herein), are especially fragile and easily damaged.
Currently, serpentine coils with spine fins are manufactured in multiple operations. First, the spine fins are applied to the tube by a machine known as a spine fin wrapper, as disclosed in U.S. Pat. Nos. 4,383,592 and 4,542,568. Later, the tube with the spine fins is transferred to a tube bender, which sequentially makes numerous individual bends until creating the desired serpentine shape.
Typically, each bend is made individually at one general location on the tube bender, while the tube indexes across that general location. To do this, the feeding of the tube into the tube bender must pause momentarily with every bend, which results in a slow, interrupted process.
Moreover, each bend of the tube shifts the completed portion of the coil (i.e., that which has already been formed into a serpentine shape) from one side to the other. This shifting movement can be tolerated if the coil is relatively small. With larger coils, however, attempting to shift the bulk and mass of the completed portion of the coil can damage the spine fins and inhibit the bending process.
Consequently, a need exists for a production piece of equipment that can readily produce large serpentine coils from spine fin tubing.
SUMMARY OF THE INVENTION
It is an object of the present invention to create serpentine coils without having to shift the entire coil back and forth with each bend of the coil.
Another object of the invention to provide a multi-operational machine that can apply spine fins to a tube as well as form the tube into a serpentine shape.
Another object is to apply spine fins to a tube while bending the tube at the same time.
Yet another object of the invention is to provide a tube bender that can form serpentine coils of various widths.
A further object of the invention is to form a serpentine coil without having to stop a tube feed roll with every bend of the tube.
A still further object is to provide a tube bender that can simultaneously bend a tube at multiple points.
Another object is to provide a method of creating tight, small radius bends by maintaining the tube in tension.
These and other objects of the present invention, which will better be appreciated when the following description of the preferred embodiment and attached drawing figures are considered, are accomplished in a tube bender that applies spine fins to a tube while simultaneously forming the tube into a serpentine shape.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
shows a top view of a tube bender simultaneously wrapping spine fins around a tube and bending the tube according to one embodiment of the invention.
FIG. 2
shows a top view of the tube bender of
FIG. 1
, but shown in another position.
FIG. 3
is a view taken along line
3
—
3
of
FIG. 2
, but with the tube omitted to show other features of the invention more clearly.
FIG. 4
is a cross-sectional view taken along line
4
—
4
of FIG.
7
.
FIG. 5
is a cross-sectional view taken along line
5
—
5
of FIG.
2
.
FIG. 6
is a cross-sectional view taken along line
6
—
6
of FIG.
2
.
FIG. 7
shows a top view of the tube bender of
FIG. 1
, but shown in another position.
FIG. 8
shows a top view of the tube bender of
FIG. 1
, but shown in another position.
FIG. 9
shows a top view of the tube bender of
FIG. 1
, but shown in yet another position.
FIG. 10
shows a top view of the tube bender of
FIG. 1
, but with the tube bender adjusted to form a narrower serpentine coil.
FIG. 11
is a view taken along line
11
—
11
of
FIG. 10
, but with the tube omitted to show other features of the invention more clearly.
DESCRIPTION OF THE PREFERRED EMBODIMENT
To create a serpentine coil
10
made of spine fin tubing
12
, a tube bender
14
includes a feed roll
16
that delivers a tube
18
through a spine fin wrapper
20
and a bending station
22
, as shown in FIG.
1
.
Spine fin wrapper
20
applies a heat conductive member, such as spine fins
24
, to the outer diameter of tube
18
to create spine fin tubing
12
. In some cases, tubing
12
starts out as
⅜″ diameter aluminum tubing with aluminum spine fins increasing its overall final diameter to
1.5″; however, various other diameters and materials are well within the scope of the invention. Spine fins
24
are preferably applied to tube
18
by having a rotating head
26
helically wrap one or more ribbons
28
of spine fins
28
around tube
18
, as feed roller
16
pays out tube
18
through a central aperture of head
26
. A roller
30
can feed the ribbon of spine fins
24
to head
26
. Further details of spine fin wrapper
20
can be found in U.S. Pat. Nos. 4,381,592 and 4,542,568, which are specifically incorporated by reference herein.
While spine fins
24
are applied to tubing
18
, station
22
bends tube
12
into the serpentine shape. To do this, station
22
includes a frame
32
with two rotating members
34
and
36
. As viewed in
FIG. 1
, member
34
rotates counterclockwise, while member
36
rotates clockwise. Upon the completion of each bend, the position of members
34
and
36
are about 90-degrees out of phase with each other. This allows dies
38
a
,
38
b
,
38
c
and
38
d
, which are mounted to members
34
and
36
, to sequentially engage tube
12
over bending region
22
of frame
32
, and thus bend tube
12
as members
34
and
36
rotate. For example, die
38
a
simultaneously bends tube
12
at points
40
and
42
as member
34
rotates from its position of
FIG. 1
to that of FIG.
2
.
The actual structure of bending station
22
can vary widely. However, in one form of the invention, members
34
and
36
each comprise a structural channel
44
welded or otherwise fixed to a shaft
46
or
48
. Referring further to
FIG. 3
, bearings
50
allow members
34
and
36
, and their respective shafts
46
and
48
, to rotate relative to frame
32
. A drive motor
52
rotates shafts
46
and
48
by way of a drive train comprising sheaves or sprockets
54
,
56
,
58
and
60
; belts or chains
62
and
64
; and gears
66
and
68
. Sprockets
56
and
58
are fixed to shaft
48
, gear
68
is fixed to shaft
46
, and gear
66
and sprocket
60
are fixed to a shaft
70
. Bearings
72
allow shaft
70
, gear
66
and sprocket
60
to rotate relative to frame
32
. Gears
66
and
68
mesh to rotate members
34
and
36
in opposite directions.
Dies
38
a-d
each has a retractable protrusion
74
that slides vertically within a C-shaped bracket
76
, which in turn is bolted to channel
44
, as shown in
FIGS. 3 and 4
. A shoulder
78
fixed relative to protrusion
74
allows a compression spring
80
acting between shoulder
78
and a lower flange of bracket
76
to urge protrusion
74
to a retracted position, as shown in FIG.
4
. However, when die
38
a
is underneath an upper plate
82
, a cam surface
84
of plate
82
applies a downward force against a roller
86
, which moves protrusion
74
to an operative position of FIG.
5
. In the operative position, protrusion
74
is able to engage and thus bend tube
12
as member
34
moves protrusion
74
across bending region
22
. Once a particular bend has been completed, member
34
moves die
38
a
out from underneath surface
84
. This allows spring
80
to push protrusion
74
back up to its retracted position where protrusion
74
disengages tube
12
, as shown in FIG.
4
. Referring to
FIG. 3
, an inclined portion
88
of cam surface
84
provides roller
86
with a gradual lead-in for moving protrusion
74
from its retracted position to its operative position.
To temporarily hold point
42
generally fixed while member
34
bends tube
12
at points
40
and
42
, a retractable anchor
90
is mounted to frame
32
in the general vicinity of point
42
. For member
36
, a similar anchor
92
is disposed at another point
100
complementary to point
42
. In some forms of the invention, anchors
90
and
92
each comprise an air cylinder
94
that extends and retracts between a release position of FIG.
5
and an extended position of
FIGS. 4 and 6
.
In operation, feed roll
16
unwraps tube
18
to create an unwrapped section of tube
15
extending from a point
96
to point
42
, with point
40
being at an intermediate position between points
42
and
96
. Fin wrapper
20
wraps spine fins
24
around tube
15
at a location between points
96
and
40
. Upon leaving fin wrapper
20
, tube
15
passes across a tube-receiving end
98
of frame
32
and extends over bending region
22
. With tube
15
and bender
14
in the position of
FIG. 1
, anchor
90
extends (see
FIG. 6
) to help hold tube
12
at point
42
, while member
34
pushes protrusion
74
of die
38
a
against tube
12
at point
40
. Tube bender
14
moving from the position of
FIG. 1
to that of
FIG. 2
completes the bend at point
42
and, at the same time, partially bends tube
12
at point
40
.
The relative rotational speed of member
34
and feed roll
16
helps maintain tube
15
in tension, which helps keep tube
12
generally straight between points
40
and
42
. In some embodiments of the invention, feed roll
16
has a certain amount of rotational drag that creates tension in tube
15
as members
34
and
36
pull tube
15
from feed roll
16
. In other embodiments, feed roll
16
is driven at a generally constant speed, while drive
52
(
FIG. 3
) is a hydraulic motor supplied with hydraulic fluid at a constant pressure. This results in a constant rotational torque being applied to members
34
and
36
, thereby limiting the tension in tube
15
.
As members
34
and
36
continue rotating from the position of
FIG. 2
to that of
FIG. 7
, member
34
moves die
38
a
out from underneath cam surface
84
. This allows spring
80
to push protrusion
74
back up to its retracted position where protrusion
74
disengages tube
12
, as shown in FIG.
4
. Also, in preparation for completing the bend at point
100
as well as initiating the next bend, member
36
moves die
38
b
along inclined portion
88
of cam surface
84
(see
FIG. 3
) to extend protrusion
74
to its operative position. In addition, anchor
92
retracts to its release position of
FIG. 5
, and anchor
90
extends to its extended position of FIG.
6
. Conventional fluid control valves can actuate anchors
90
and
92
at the precise time in response to conventional limit switches that sense the position of member
34
or
36
.
Next, members
34
and
36
move from their positions of
FIG. 7
to that of FIG.
8
.
FIG. 8
is similar to
FIG. 1
; however, member
34
and die
38
a
do the bending in
FIG. 1
, while in
FIG. 8
, member
36
and die
38
b
do the bending. Thus, in
FIG. 8
, die
38
b
is in its operative position, anchor
92
is in its extended position, and anchor
90
is in its release position. Also, die
38
a
being out from underneath upper plate
82
is in its retracted position. This allows die
38
a
to pass over the completed serpentine portion
10
of tube
12
that is resting upon a support structure
102
of frame
32
.
From the positions of
FIG. 8
, members
34
and
36
rotate to the positions shown in FIG.
9
.
FIG. 9
is similar to
FIG. 2
; however, die
38
b
of member
36
, rather than die
38
a
of member
34
, has just completed a bend. As members
34
and
36
continue rotating, die
38
c
is next to bend tube
12
, followed by die
38
d
, and then die
38
a
comes around again to make yet another bend, which begins another cycle. As the repeating cycles continue, the serpentine portion
10
of the coil grows to the right, as viewed in
FIG. 9
, until the coil is cut to a desired length and removed from support structure
102
. From there, the serpentine coil can be made into a complete heat exchanger, which may include framework, manifolds, inlet and outlet ports, etc. The coil may also be formed further into a shape other than just flat.
Although, coil
10
has a specific width
104
, tube bender
14
can be adjusted to make a serpentine coil
10
′ having a narrower width
106
, as shown in FIG.
10
. To do this, dies
38
a-d
can be moved closer to their corresponding shaft
46
or
48
. In
FIG. 11
, for example, bracket
76
of die
38
a
is unbolted from mounting holes
108
of member
34
and reinstalled closer to shaft
46
. Anchors
90
and
92
are also moved closer to each other in a similar unbolting/bolting manner. Of course, there are a wide variety of other common methods of repositioning tooling such as having a lead screw move the dies and anchors along guide tracks.
Although the invention is described with reference to a preferred embodiment, it should be appreciated by those skilled in the art that other variations are well within the scope of the invention. For example, to minimize the bending of tube
15
just as it leaves head
26
, spine fin wrapper
20
can be installed much farther away from tube-receiving end
98
than what is shown in the drawing figures. Also, guides can be added to help guide tube
15
as tube
15
travels from head
26
to tube-receiving end
98
. Therefore, the scope of the invention is to be determined by reference to the claims, which follow.
Claims
- 1. A tube bender adapted to bend a tube into a serpentine shape, comprising:a frame having a tube-receiving end adapted to receive the tube, a support structure adapted to support the serpentine shape, and a bending region interposed between the tube-receiving end and the support structure; a first anchor supported by the frame and being adapted to engage the tube; a second anchor supported by the frame and being adapted to engage the tube, wherein the first anchor and the second anchor are spaced apart from each other and are closer to the support structure than the tube-receiving end; a first rotating member; a second rotating member; a first die adapted to engage the tube in the bending region and being moveable relative to the frame to bend the tube about the first anchor; a second die adapted to engage the tube in the bending region and being moveable relative to the frame to bend the tube about the second anchor; a third die adapted to engage the tube in the bending region and being moveable relative to the frame to bend the tube about the first anchor; and a fourth die adapted to engage the tube in the bending region and being moveable relative to the frame to bend the tube about the second anchor; wherein the first die and the third die are attached to the first rotating member, and the second die and the fourth die are attached to the second rotating member.
- 2. The tube bender of claim 1, wherein the first anchor is moveable between an extended position to engage the tube and a release position to disengage the tube.
- 3. The tube bender of claim 1, wherein movement of the first die and the second die is out of phase to each other.
- 4. The tube bender of claim 1, wherein the first die, the second die, the third die and the fourth die are adapted to engage the tube sequentially as the first rotating member and the second rotating member rotate.
- 5. The tube bender of claim 1, wherein the first rotating member and the second rotating member rotate substantially 90-degrees out of phase relative to each other.
- 6. The tube bender of claim 1, further comprising a feed roll adapted to pay out the tube toward tube-receiving end of the frame.
- 7. The tube bender of claim 6, further comprising a spine fin wrapper interposed between the feed roll and the tube-receiving end of the frame, wherein the spine fin wrapper is adapted to wrap a heat conductive member around the tube.
- 8. The tube bender of claim 1, wherein the first die is further moveable between an operative position and a retracted position, wherein the operative position allows the first die to engage the tube and the retracted position allows the first die to travel past the tube.
- 9. The tube bender of claim 8, further comprising a cam surface associated with the first die, wherein the first die moves between the operative position and the retracted position in response to the die moving relative to the cam surface.
- 10. The tube bender of claim 8, further comprising a spring that urges the first die to the retracted position.
US Referenced Citations (22)
Foreign Referenced Citations (1)
Number |
Date |
Country |
2732719 |
Mar 1978 |
DE |