Note: Descriptions are shown in the official language in which they were submitted.
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INTEGRATED HEAT PIPE VENT CONDENSER
This application is a division of patent application number 2,320,493
filed on September 21, 2002 and entitled INTEGRAGED HEAT PIPE VENT
CONDENSOR.
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates generally to the field of
industrial and utility power generation vapor condensers and, in
particular, to a new and useful heat pipe vent condenser
(HPVC)integrated into a heat pipe steam condenser for the
condensation of steam and concurrent removal of unwanted, non-
c:ondensable gases .
Vent condensers are used to separate and drain the condensable
portion of a multi-component vapor flow. Non-condensable gases are
exhau~~ted from the vent condenser. Vent condensers typically have a
shell and tube or a LJ-tube heat. exchanger with a coolant flow over
the tube side to condense the condensable portion of the multi
component vapor flow.
A heat pipe steam condenser has several modules of heat pipes
stacked in series to receive a flow of stream. As the working vapor,
usually in the form of steam, moves through
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the modules, water vapor content in the gas space is reduced through
condensation to water
on the outside surfaces of the heat pipes at the evaporator ends thereof,
while the
concentration of non-condensable gases increases.
At one or more points within the heat pipe steam condenser, usually at the
back-end
s of the last condenser module where the non-condensable gas fraction is
greatest, the non-
condensable gases are aspirated through a separate vent condenser. The gases
are aspirated
prior to exhausting these gases to a downstream eductor or other suitable
device for
maintaining the non-condensable gas flow through the vent condenser. The
purpose of the
vent condenser is to remove as much of the working vapor as possible from the
vapor flow
1 o mixture that the operating temperature of the heat pipe will permit. This
minimizes the
energy and flow requirements of the eductor and minimizes the working vapor
loss from the
heat pipe steam condenser.
All known prior vent condensers have been installed externally to the heat
pipe steam
condenser. Such vent condensers normally use a coolant supply, such as cold
water, to
1 s condense the working vapor on heat exchanger surfaces before exhausting
non-condensable
gas portions from the system.
SUMMARY OF' THE INVENTION
It is an object of the present invention to provide an integrated condensable
gas
2o recovery system to eliminate connections and piping between vent condensers
and heat pipe
steam condensers. It is a further object of the invention to provide a heat
pipe condenser
system which does not require a separate coolant and is not subject to
freezing.
Accordingly, an integrated heat pipe vent condenser for a heat pipe steam
condenser
is provided wherein the vent condenser is located within a heat pipe steam
condenser
2s module. The~integrated vent condenser has a plurality of heat pipes with
evaporator ends
positioned within a vent condenser casing located in a vapor duct of the heat
pipe steam
condenser. The vapor flow through the steam duct enters the vent condenser
casing and
travels through the casing in a path defined by a plurality of baffles,
releasing heat to the
evaporator ends of the heat pipes and causing condensable gases to condense on
the baffles
3o and evaporator ends surfaces. Condensed gases are drained through a
downcomer. Non-
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condensable gases are exhausted from the casing to an eductor, manifold, or
other exhaust
system for disposal.
The various features of novelty which characterize the invention are pointed
out with
particularity in the claims annexed to and forming a part of this disclosure.
For a better
understanding of the invention, its operating advantages and specific objects
attained by its
uses, reference is made to the accompanying drawings and descriptive matter in
which a
preferred embodiment of the invention is illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
to In the drawings:
Fig. 1 is a side sectional elevational view of an integrated heat pipe vent
condenser
of the invention;
Fig. 2 is an enlarged side sectional elevational view of the lower end of the
vent
condenser of Fig. 1, taken along line A-A of Fig. l;
Fig. 3 is a top plan view of the vent condenser of Fig. 2, taken along line B-
B of Fig.
2;
Fig. 4 is a rear elevational view of the vent condenser of Fig. 2, taken along
line C-C
of Fig. 2 and
Fig. 5 is a schematic view of a heat pipe steam condenser according to the
invention.
DESCRIPTION OF THE PREFERRED EMBOD)QVVIENTS
Referring now to the drawings, wherein like reference numerals refer to the
same or
functionally similar elements throughout the. several drawings, Fig. 1
illustrates a heat pipe
vent condenser (HPVC) generally referred to as 10. Heat pipes 20 are
positioned through a
steam duct 30 in the HPVC 10, which is part of a heat pipe steam condenser
module 120,
such as shown in Fig. 5.
As seen in Fig. 5, a steam flow, generally shown by line S and containing
condensable and non-condensable gases in a vapor mixture, is provided from
steam header
100 through vapor duct 30 to a plurality of heat pipe steam condenser modules
120 arranged
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in series. Each heat pipe steam condenser module 120 is provided with a fan
140. Within
the heat pipe steam condenser modules 120, a plurality of heat pipes 20 are
arranged in
bundles 130 in communication with the working vapor, usually steam, in vapor
duct 30 for
removing heat from the steam flow to cause condensable gases to condense on
the heat pipe
surfaces.
Returning to Fig. 1, evaporator ends 2S of heat pipes 20 extend through vapor
duct
30. The upper ends of heat pipes 20 are condenser ends 24. A plurality of heat
dissipation
fins 22 are provided along the length of condenser ends 24.
Inside vapor duct 30, vent condenser casing SO surrounds evaporator ends 25 of
heat
to pipes 20. Vent condenser casing SO has inlet 40 at a lower end and outlet
62 at an upper
end. In Fig. 2, vapor flow S enters at inlet 40 and winds in a serpentine path
upwards
through horizontal baffles SS positioned between evaporator ends 25. Vapor
flow S rises
through the baffles 55, giving off heat to evaporator ends 25 and causing
additional
condensable gases to condense on the surfaces of evaporator ends 25 and
baffles 55. The
t s vapor flow S exits the casing SO through outlet 62, from where it is
directed out of the system
to either an eductor 60, a manifold, or other exhaust system for exhausting
the non-
condensable gases in a known manner.
A downcomer 80 is provided on casing SO for draining condensed gases and
vapors
from vapor flow S. As seen in Figs. 1 and 2, the casing 50 and heat pipes 20
are oriented
20 obliquely to the horizontal, in an inclined position.
Fig. 4 shows.a plurality of drain openings 8S through the back wall of casing
SO into
downcomer 80. The drain openings 85 are located at the same elevation as the
lower end of
the baffles 55 in casing 50. The drain openings 85 are designed to prevent the
vapor flow S
from traveling directly to downcomer 80 by reducing the opening to a size that
allows only
25 liquid to flow through and eliminates all other excess area of the opening.
Accordingly,
these openings help reduce re-entrainment of the condensate by removing the
condensate
immediately, thereby offering an improvement over the prior art.
The downcomer 80 drains through trap 75 to drain outlet 70 and back into vapor
duct
30. Condensate which drains into vapor duct 30 is removed in manner
conventional to heat
3o pipe steam condensers. One or more weep holes 78 may be provided in trap 7S
to allow
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condensate to drain directly from the trap in the event that a freezing
condition occurs,
although the present invention was designed specifically to avoid such
conditions. Trap 75
otherwise prevents vapor flow from entering the vent condenser casing SO
through
downcomer 80.
Fig. 3 shows a top plan view of the vent condenser. Baffle ends 54 are ideally
situated so that all of the evaporator ends 25 intersect all of the baffles
55, thereby
maximizing the heat exchange efficiency. An alternate baffle arrangement in
which the
baffles are vertically disposed, rather than inclined horizontally, is also
possible. In such a
vertical arrangement, drain openings may be provided adjacent to the bottom of
casing 50
to and/or adjacent to the baffle ends 54 to allow condensate to pass into
downcomer 80.
While the casing 50 surrounding heat pipes 20 has been shown to be square or
rectangular in the drawings, it is anticipated that other co~gurations, such
as cylindrical,
may be more economical to install and/or operate. Likewise, any arrangement of
baffles 55
within vent condenser casing 50 is possible (i.e., diagonal, concentric,
etc.). Further, the
is number of heat pipes 20 encased in the casing SO may be varied according to
the desired flow
characteristics and space requirements of the system.
Several advantages are obtained from the integrated heat pipe vent condenser
of the
invention. In particular, it is believed that the freezing condition which can
occur in other
types of vent condensers is eliminated, since there is no liquid coolant which
must be
20 maintained above a freezing point. Further, the heat pipes used in the
present invention are
an efficient passive heat transfer mechanism, with no need for moving
mechanical parts or a
forced coolant circulation system. Consequently, chemical cleansers, coolant
pumps,
collection tanks, external piping, valves, and other equipment required by
prior art vent
condensers, as well as the maintenance and costs associated therewith, are
eliminated.
25 While a specific embodiment of the invention has been shown and described
in detail
to illustrate the application of the principles of the invention, it will be
understood that the
invention may be embodied otherwise without departing from such principles.
