Note: Descriptions are shown in the official language in which they were submitted.
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TRANSFORMER COOLING STRUCTURE
BACKGROUND OF THE INVENTION
Field of the Invention:
This invention relates to a heat exchanger unit
for cooling of cooling fluid of an electrical transformer,
or other device7employing a circulating fluid coolant.
Description of the Prior Art:
Tanks containing a transformer submerged in a
cooling fluid may be provided with a radiator, or heat
exchanger, for transferring heat from cooling fluid to
ambient air. The radiators or heat exchangers vary in
construction, depending upon several factors, such as the
rating of the transformer. Prior art heat exchangers
differ in their structural form, but are generally com-
plicated for which reason they have been an unnecessarily
costly addition to the transformer tank per se.
Associated with the foregoing has been a problem
of reducing the volume of the cooling fluid in the trans-
former in order to reduce the unit volume and therefore
cost of the cooling fluid.
SUMMARY OF THE INVENTION
In accordance with this invention it has been
found that the foregoing problems may be overcome by
providing a tank for a transformer submerged in a cooling
fluid, ~ tank comprising a preferably rectangular cross
2~ section having opposite side walls, opposite edge walls,
and top and bottom end walls, each opposite side wall
including a plurality of cooling panels extending outward-
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ly from the plane of the wall which panels comprise a pairof oppositely disposed sides having facing peripheral edge
portions and end portions that are secured together in a
fluid-tight seal, the sides being sheet metal members
formed to include aligned corrugated surfaces forming
spaced fluid-conducting headers and fluid conduits there-
between, each side comprising an out-turned flange along
the edges adjacent the tank, the edges of the flanges of
adjacent panels being secured together in a fluid-tight
manner to form the corresponding side wall of the tank,
said walls having inlet and outlet means for said fluid
and communicating with the spaced headers of corresponding
panels.
The advantage of the tank design of this inven-
tion is that it combines several features simplifying thedesign and construction of a tank including the combina-
tion of prior separate functions of cooling and bracing,
the use of welds to reduce metal gauge, and integral
stamping of conducting headers and fluid conduits in the
panels.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic view of a transformer
tank with heat exchanger panels extending from opposite
side walls thereof in accordance with this invention;
Fig. 2 is an exploded view of the device of Fig.
l;
Fig. 3 is an enlarged elevational view, taken on
the line III-III of Fig. 1 of a cooling panel, with an
associated transformer tank portion shown partially in
section;
Fig. 4 is an enlarged plan view taken on the
line IV-IV of Fig. l of a plurality of cooling panels;
Fig. 5 is an enlarged, fragmentary, horizontal
sectional view taken on the line V-V of Fig. 3;
Fig. 6 is an enlarged vertical sectional view
taken on the line VI-VI of Fig. 3; and
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Fig. 7 is an enlarged vertical sectional view
taken on the line VII-VII of Fig. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In Fig. 1 a transformer structure is generally
indicated at 11 and it comprises a tank 13 which contains
a transformer unit 15, and which includes two banks 17, 19
of heat exchanger panels 21 extending from opposite sides
of the tank.
Although the tank 13 is described as containing
a transformer unit 15, it is understood that other elec-
trical apparatus that is operated and submerged within a
cooling fluid is within the scope of this invention.
The transformer structure 11 (Fig. 2) is com-
prised of a pair of opposite end walls 23, 25, a bottom
wall 27, a top wall 29 (Fig. 1), opposite side walls 31,
33 on each of which a plurality of the heat exchanger
panels 21 are mounted. In addition, four similar support
braces or angle members 35 are located at the corners
where the several respective walls converge. The several
walls 23, 33 and members 35 are secured together in a
suitable manner, such as by welds along adjacent edges to
form the rectangular structure shown in Fig. 1. It is
understood, however, that although a rectangular structure
is disclosed, any other structure, such as octagonal or
cylindrical may be used. Also, although two heat ex-
changer banks 17, 19 are provided on opposite sides, any
other number of banks, such as one bank 17 or three or
more banks of similar structure, may be provided on cor-
responding external walls of the tank.
To facilitate assembly and rigidity of structure
the end walls 23, 25 include similar flanges 37, 39. The
flanges 37 at the lower ends of the end walls 23, 25 co-
operate with the angle members 35 to reinforce each other.
Bars 40 reinforce the bottom wall and contribute to the
rigidity of the planar end walls 23, 25. The flanges 37
at the upper end of the end walls likewise cooperate with
the upper pair of angle members 35 for reinforcing the
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members with the walls and for providing a base for weld-
ing of the top wall 29 in place. The inturned flanges 39
on both end walls provide a base on which the side walls
31, 33 are welded. The end wall 23 comprises an opening
41 for the mounting of low voltage bushings (not shown).
Likewise, the end wall 25 comprises a number of openings
43 in which high voltage bushings may be mounted. The
openings 41, 43 are disposed merely to indicate that such
bushings may be mounted in the end walls. However, the
bushings may be mounted in openings in the top wall 29.
In accordance with this invention each heat ex-
changer panel 21 is~comprised of a pair of oppositely
A disposed sides 45, 471which are sheet-like members formed
from sheet stock by rolling in one direction to form
oppositely disposed corrugations 49 and 51 (Fig~. 3, 5)-.
Corresponding pairs of corrugations 49, Sl are aligned and
oppositely disposed (Fig. 5) to provide longitudinally ex-
tending fluid flow conduits 53 between which concave por-
tions 55, 57 are disposed in aligned, surface-to-surface
contact for fluid-tight separation between adjacent con-
duits 53. As shown, the concave portions 55 and 57 are in
surface-to-surface contact, but may be slightly spaced.
For reinforcement the panel side 45 comprises a plurality
o longitudinally extending, transversely spaced longi-
tudinal portions, such as portions 59, 61 (Fig. 5), which
are aligned with corresponding portions 63, 65 in the
panel side 47. The corresponding portions 59, 63 are
secured together, such as by spot welding at 67 (Fig. 3),
whereby the facing panel sides 45, 47 are retained intact
to serve as heat exchangers for cooling fluid flowing
through the conduits 53.
Moreover, the panel sides 45, 47 comprise convex
portions 69, 71, respectively, which extend transversely
of the panels and which are aligned (Figs. 5, 7) to pro-
vide a fluid-conducting header 73. A similar fluid con-
ducting header 75 is provided at the lower end of the
panel (Figs. 3, 6) by providing the panel sides 69, 71
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with convex portions 77, 79, respectively. At the upper
end of the panel 21 a similar fluid conducting header 81
is provided by forming convex portions 83, 85 (Fig. 3) at
the upper end of the panels 21. All of the fluid conduct-
ing headers 73, 75, 81 are formed by the alignment of the
corresponding convex portions which in turn are formed by
stamping the previously corrugated sides to provide the
convex portions preferably perpendicular to the conduits
53. When assembled the upper and lower transverse edges
as well as the longitudinal edge are welded at 87, 89, 91
in surface-to-surface fluid-tight contact thereby provid-
ing a fluid-tight panel which serves as a heat exchanger
for the cooling fluid from the interior of the tank 13
whereby fluid entering one of the headers flows vertically
through the conduits 53 to another header from where it is
returned to the tank chamber.
In accordance with the invention each panel side
45 and 47 is provided with an out-turned flanges 93, 95,
respectively (Figs. 3, 4, 5). A plurality of panels 21
are assembled by aligning the flanges 93, 95 of adjacent
panels in edge-to-edge abutment (Fig. 4), where they are
secured together in a fluid-tight manner, such as by simi-
lar welds 97 to provide a planar side (Fig. 2) for each
side of the tank 13. Alternatively, the flanges 93, 95
may be overlapped for welding rather than butted as shown.
Accordingly, a plurality of assembled panels 21, such as
by welds 97, comprise a side of the tank 13. In the
embodiment disclosed in the drawings, two opposite sides
of the tank are provided with similar side walls. It is
understood that one or more such walls may be provided,
for example, where the cross section of the tank is
greater than rectangular such as hexagonal or octagonal.
Indeed, a cylindrical tank may have one or more arcuate
sides thereof covered by sections of assembled panels 21
as described above.
As shown more particularly in Fig. 2, each panel
21 comprising panel sides 45, 47, comprises openings 99,
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lOl, and 103. Each opening 99 (Fig. 3) communicates with
a corresponding fluid conducting header 81. Likewise,
each opening 101 communicates with a corresponding fluid
conducting header 73, and each opening 103 communicates
with a corresponding lower fluid conducting header 75.
As shown in Fig. 1, the assembly of each heat
exchanger panel 21 on opposite sides of the tank 13 is
secured in place in a suitable fluid-tight manner, such as
peripheral welds, along the upper and lower ends of the
assembled flanges 93, 95 as well as along opposite ver-
tical edges, such as a weld 105. The vertical welds, such
as the weld 105, are secured to the vertical flanges 39
(Fig. 2) and the horizontal welds across the top and bot-
tom of the panels 21 are secured to the flanges of the
lS upper member 35 and the member 40. Accordingly, a fluid-
tight joint is formed by the banks 17, 19 of panels 21 on
opposite sides of the tank 13.
The bottom wall 27 as well as the top wall 29
are secured in place by fluid-tight joints between ends
and edges of the top and bottom walls with adjacent other
walls and members of the tank 13. The joints therebetween
preferably comprise welds (not shown).
As shown in Fig. 3, electrical apparatus such as
the transformer unit 15 is contained in the tank 13 where
it is supported on the bottom wall 27. The unit 15 is
submerged within a coolant fluid having a level 107 which
is at least as high as the openings lOl which communicate
with the fluid conducting headers 73. As the temperature
of the transformer unit 13 increases during operation, the
heated coolant fluid rises to the level 107 and moves
through the openings 101, the headers 73, downwardly
through the conduits 53 to the lower header 75 and then
through the openings 103 to the lower portion of the tank
13, thereby completing a cooling cycle in accordance with
this invention. The upper portions of the heat exchanging
panels 21 above the fluid conducting headers 73, which
comprise the upper ends of the conduits 53 and the fluid
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conducting header 81, provide for air circulation between
the upper portion of the tank 13 and the heat exchanging
panels 21. An additional function of the upper portions
of the panels is to absorb expansion of the volume of the
1uid where excess heating occurs. The upper portions of
the several panels 21 above the fluid conducting headers
73 extend to the upper end of the side walls and thereby
resist pressures in the tank which may occur from time to
time.
Where for the given tank a larger transformer
unit 13 may be provided, the upper end of which may extend
above the level of the intermediate fluid conducting
header 73, such header may be deleted and the fluid level
107 raised to the upper fluid conducting header 81. In
such case, the heated coolant fluid passes through the
openings 99, the header 81 and then downwardly through the
several conduits 53 to the header 77 from where it re-
enters the tank 13 through the openings 103.
In conclusion, the tank and heat exchanger
assembly of this invention provides for a heat exchanger
unit having corrugated walls to reduce the volume of the
coolan~ fluid and to provide for more efficient heat
exchange between the fluid and the ambient air. In addi-
tion, by mounting the several heat exchanging panels
perpendicular to the walls of the tank, the panels rein-
force the walls in combination with the several welded
joints and thereby enable the use of stock sheet having a
smaller gauge, such as 0.040 to 0.060 inch instead of a
higher thickness such as 0.25 to 0.375 inch.
