Note: Descriptions are shown in the official language in which they were submitted.
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AIR-COOLED VAPOR CONDENS~S
.~,
This invention relates to improvements in
air-cooled vapor condensers in which vapor such as steam is
passed through the tubes of one or more bundles of tubes
which are disposed across one end of a fan ring of an axial
flow fan to cause the vapor to be condensed as air from the
fan flows therepast.
In many such condensers, the fan is supported with
its axis of rotation perpendicular to the horizontal and the
10 axes of the tubes of the bundle or bundles are inclined with
respect to the horizontal to dispose one end above the other
in order that condensate may flow downwardly therethrough.
; There may be two such bundles arranged end-to-end and
extending in opposite directions to form a "V" between them.
For example, the bundles may be arranged as an inverted "V"
above a forced draft fan, with vapor being introduced into
the upper ends of the tubes at the apex-of the "V"-and
I drained from their lower ends.
Ordinarily, each bundle comprises two or more
20 parallel rows of tubes with headers at each end thereof
providing common steam inlets and common condensate outlets.
However, as disclosed in ~. S. Patent No. 4,168,742, each
~bundle may consist of only a single row of tubes, with each
such tube be-ing in the form of an elongate "box" having
- parallel side walls which extend in the direction of air
flow therepast and which are considerably longer than the
width of the tube.
It is also standard practice to provide such tubes
with fins which extend their outer surfaces and thereby
increase their abilities to exchange heat - i.e., cool the
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vapor. These fins may be discrete in the sense that each tube has
its own fins, or the fins may comprise plates which are common to the
tubes which extend through them. Or, as shown in the aforementioned
patent, the fins may extend between and thus be common to the side
walls of adjacent tubes, whether in the form of individual fins,
plates or pleats which are folded back and forth between the tubes.
In any event, the fins conventionally extend
perpendicularly to the axes of the tubes, which, of course,
facilitates the mounting of discrete fins which are wrapped about the
tube or extruded from the tube surface, or, for that matter, which
comprise discs or plates having holes which are slid over and then
attached about the tube. When, however, bundles of such finned tubes
are mounted in an air-cooled steam condenser of the type above
described, air from the fan must change direction or bend in order to
flow between the fins and thus past the tub~s. This, of course, calls
for the supply of considerable energy or power to the fan,
particularly when, as is normally the case, the fins are inclined at
an angle of sixty degrees (60) or more with respect to the vertical,
and are spaced apart as little as 0.08 inches.
The invention in one broad aspect pertains to a tube
through which vapor may pass and over which air may flow, and fins
mounted across the tube and extending other than perpendicularly to
' the axis of the tube. The invention also comprehends a bundle of
; such tubes in a row.
More particularly the invention seeks to provide an air-
cooled vapor condenser of the type described which enables the fan
to be operated with less power, and, more particularly, which permits
the air to flow past the finned tubes thereof without bending.
Preferably such a vapor condenser has the aforementioned
~box" type finned tubes which are particularly well suited.
These and other aspects are accomplished, in accordance
with the illustrated embodiemnts of the present invention, by a vapor
condenser of the type described wherein the fins extend other than
perpendicularly to the axes of the tubes of each bundle on which they
are mounted, and, more particularly, extend parallel to the axis of
rotation of the fan and thus the direction of air flow. As
a~
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illustrated, there are a pair of bundles which are of the
type above-mentioned in that they are arranged end-to-end
and have at least one row of such finned tubes whose axes
are inclined with respect to the axis of the horizontal to
dispose one end above the other, and fornl a "V" between
them.
As also illustrated, and in accordance with the
preferred embodiments of the invention, each bundle consists
of only a single row of tubes of the above-described "box"
shape, and thus having parallel side walls which extend in
the direction of air flow therepast and which are
considerably longer than the width of the tubes. In
accordance with one embodiment, the fins are plates through
which the tubes of each row extend. In accordance with
alternative embodiments, individual fins extend between the
side walls of the tubes, either as flat strips or as pleats
which are folded back and forth between the side walls of
the tubes.
As will be appreciated, fins of these latter types
would be of the same basic construction regardless of the
inclination of the tubes and thus the fins with respect to
the tubes. Also, even when in plate form, the fins would
merely require the forming of rectangular rather than
oval-shaped holes to fit the tubes.
In the drawings, wherein like reference characters
are used throughout to designate like parts:
Fig. 1 is a diagrammatic cross-~sectional view of
an air-cooled vapor condenser constructed in accordance with
the present invention, as seen along in the plane indicated
-by broken lines 1--1 of Fig. 2;
Fig. 2 is a side view of the vapor condenser of
- Fig. 1, as seen from the broken lines 2--2 of Fig. l; and
Figs. 3, 4 and 5 are enlarged perspective views of
portions of tube bundles for the condenser having fins which
are co~structed in accordance with the alternative
embodiments of the invention.
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The vapor condenser which is shown in ~ig. 1, and
indicated in its entirety by reference character 10,
includes a fan ring 11 which is open at both ends and
adapted to be disposed in a generally horizontal position.
A fan 12 is mounted on a shaft 13 for rotation about a
substantially vertical or perpendicular axis, and with its blades
arranged to cause the air to move upwardly through the fan ring,
as indicated by the arrows in Fig. 1.
A pair of tube bundles 14 are mounted in
end-to-end relation across the upper open end of the fan
ring, as by means of a plenum 17, and thus in a position for
air from the fan to flow therepast. As previously
described, each such bundle 14 consists of a single row of
tubes 15 having their axes disposed within a plane(e.g. Pl in
Fig. 1) which is inclined with respect to the horizontal and
- thus with respect to the direction of air flow. More
particularly, in the illustrated and preferred embodiment of
the invention, the tubes of the bundles are inclined in
opposite directions and form an inverted ~v~ between them.
As shown, vapor such as steam is supplied to a
header 16 extending the length of the bundles and common to
the upper ends of the tubes of both bundles. Condensate
from the tubes of the bundles drains into headers 18 each
common to the tubes of one bundle. As previously described,
and as well known in the art, upon the flow of air past the
tubes ? the vapor is condensed within the tubes and drains
downwardly therefrom into the headers 1~.
As shown, and as previously mentioned, each bundle
14 consists of only a single row of tubes, and the tubes are
of an elongate box shape having parallel side walls 19 which
extend in the direction of air flow therepast, and which are
; considerably longer than the width of the tube. The
advantage of bundles having a single row of tubes of this
construction is known in the art, including the
aforementioned U. S. Patent 4,168,742, a~d hence the
detailed interior construction of the tubes need not be
described herein.
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In the embodiment of the vapor condenser shown in
FIgs. l and 2, the tubes 15 extend through holes in closely
spaced-apart plate fins 20. However, in accordance with
alternative embodiments of the invention, the fins may
comprise pleats 21 which, as shown in Fig. 4, are folded
back and forth between the sides of adjacent tubes, with the
bends in the pleats being welded or otherwise secured to the
side walls of the tubes. In accordance with a still further
embodiment of the invention, the fins may comprise
individual sheets or strips 22 extending between and secured
at their opposite ends to the side walls of adjacent tubes.
In each case, however, the fins, whether of plate,
pleated or individual form, extend other than
perpendicularly to the axis of the tubes, as is common in
the art, and, more particularly, extend parallel to the
direction of air flow from the fan 12. Hence, and as
previously described, the air is able to -flow between the
fins and between the fins without bending, and thus with a
minimum of power requirements. This is particularly
advantageous when, as previously described, the tube bundles
may be inclined at an angle approximately sixty degress
(60) with respect to the horizontal, so that fins
perpendicular to the axis of the tubes would require that
the air from the fan bend at a complementar~ angle, or about
one hundred twenty degrees (120). This results, of course,
from the fact that-the fins are spaced relatively closely to
one another, and perhaps as close as 0.08 inches apart, so
that no portion of the air may pass between them without
bending.
From the foregoing it will be seen that this
invention is one well adapted to attain all of the ends and
- objects hereinabove set forth, together with other
advantages which are obvious and which are inherent to the
apparatus.
; It will be understood that certain features and
~ subcombinations are of utility and may be employed without
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reference to other features and subcombinations. This is
contemplated by and is wi~hin the scope of the claims.
As many possible embodiments may be made of the
invention without departing from the scope thereof, it is to
be understood that all matter herein set forth or shown in
the accompanying drawings is to be interpreted as
illustrative and not in a limiting sense.
