Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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TITLE
COLLAPSIBLE MIST ELIMINATOR
CROSS-REFERENCE TO RELATED APPLICATIONS
None.
5 STATEMENT REGARDING FEDERALLY
SPONSORED RESEARCH AND DEVELOPMENT
None.
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a separator for
15 separating material particles from a gas, especially
liquid droplets from gases.
Fine particles have been removed from gases in the past
for a variety of reasons in a variety of applications.
A typical application is the removal of liquid droplets
forming a mist escaping from evaporative coolers,
scrubbers and similar structures. Typically this is
done by providing a plurality of parallel, zig-zag or
sinuously shaped profiles spaced apart from one another
in parallel relationship.
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A very successful apparatus for separating liquid
particles from gases, which is also referred to as a
mist eliminator vane, is disclosed in U.S. Patent No.
3,953,183. As seen in that patent the mist eliminator
5 vanes are profiles that are in a wave or sinusoidal
shape which has a separating chamber (also called a
collection pocket) opening to the direction of the gas
flow. The separating chamber distorts the gas flow
along the vane because of the sudden changes of
10 direction in the profile and the position of the
chamber. The curved vane and separating chamber
structure of the mist eliminator disclosed in Patent
No. 3,953,183 produces an improved separation
efficiency.
In use, the shape of the mist eliminator vanes and the
placement and positioning of the separating chamber
formed by the flange on the vane cause a substantial
pressure drop in the gas flowing from the inlet side of
20 the vane to the outlet side of the vane. In some
temperature and humidity conditions when evaporative
cooling is not needed, the evaporative cooler is not
operated and no mist is created, but air escaping from
the evaporative cooler or other device must still pass
25 through the mist eliminator and encounter the resulting
pressure drop, thereby unnecessarily consuming energy.
SUMMARY OF THE INVENTION
30 It is an object of the present invention to provide an
improved apparatus for separating material particles
from gases in which the configuration of the apparatus
can be varied in order to vary pressure drop during
use.
Yet another object of the present invention is to
provide a separator or mist eliminator vane that
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includes an integral separating chamber for separating
material particles from a gas while allowing the shape
of the separating chamber to be selectively varied in
order to vary pressure drop along the vane.
Yet another object of the present invention is to
provide an improved mist eliminator vane structure.
In accordance with an aspect of the present invention a
separator of particles from gases, i.e., a mist
eliminator vane, or separator is provided having first
and second vane sections with opposed ends and means
for pivotally connecting those opposed ends. The vane
includes an upstream end on the first vane section and
15 a downstream end on the second vane section. The
second vane section has projecting flange or blade
which extends away from the second vane section towards
the first vane section adjacent the means which
pivotally connects the opposed ends of those vane
20 section. As a result, a separating chamber having an
open mouth opening towards the upstream end of the vane
is formed. By this structure the vane sections may
pivot relative to each other about the pivotally
connecting means between a first position wherein the
25 flange is spaced from the first vane section to open
the mouth of the separating chamber and a second
position wherein a portion of the flange is adjacent
the first vane section to substantially close the mouth
of the separating chamber thereby to reduce pressure
30 drop of gas flowing past the separator when the action
of the separator is not needed.
The above, and other objects, features and advantages
of this invention will be apparent in the following
35 detailed description of preferred embodiments thereof
which are described with reference to the accompanying
drawings as follows:
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BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a transverse sectional view of a plurality
of profiles or mist eliminator vanes arranged in
5 parallel and vertically with regard to each other,
illustrating the prior art structure;
Figure 2 is a transverse sectional view similar to
Figure 1 of two vanes constructed in accordance with
10 the present invention with their separating chamber in
the open position;
Figure 3 is a view similar to Figure 2 showing the
separator vanes in their closed position;
Figure 4 is an enlarged view similar to Figures 1 and 2
showing a single vane, its mounting arrangement and its
movement from its open to its closed position;
20 Figure 5 is a view similar to Figure 2 illustrating
another embodiment of the present invention with the
separating chamber of the vane in its open position;
Figure 6 is a view similar to Figure 3 showing the
position of the vane of Figure 5 with its separating
chamber in the closed position; and
Figure 7 is a pressure chart showing the difference in
pressure loss between the open and closed positions of
30 an exemplary mist eliminator vane constructed in
accordance with the present invention.
DETAILED DESCRIPTION OF INVENTION
35 Referring now the drawings in detail, and initially to
Figure 1, a series of mist eliminator vanes constructed
in accordance with the 'teachings of U.S. Patent
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No. 3,953,183 are illustrated. Each vane or wave
profile 10 is mounted in any convenient and known
manner in the discharge end of an evaporative cooler or
other structure which discharges particles in a gas
5 stream. In an evaporative cooler application the
particles are small liquid droplets in a mist in air.
As is known in the art, the vanes 10 are arranged
parallel to each other at the discharge end of the
10 evaporative cooler to receive the discharged mist and
gas stream. The gas stream enters the inlet end 12 of
the pack of mist eliminator vanes at the inlet edges 14
of the vanes. As illustrated in Figure 1 the vanes are
generally sinusoidal in shape and the air is deflected
15 along the vanes as indicated by the arrows. In the
illustrative embodiment, the mist eliminator vane is
formed of three arc sections, including a first or
inlet convex section 16, a second central concave
section 18 and a third convex discharge section 20
20 which leads to the discharge end 22 of the vane. From
the discharge end the air escapes to the atmosphere.
The particular curvatures of these vane sections are
described in detail in Patent No. 3,953,183 and those
details do not form part of this invention.
25
The central sections 18 of the vanes have a plurality
of serrations 24 formed therein. The second or central
section 18 of each vane also has a flange or blade 26
extending tangentially therefrom towards the direction
30 of air flow to define a separating chamber 30 having an
open mouth 28 between the flange and vane section 18.
As appears in Figure 1 and as described in detail in
Patent No. 3,953,183, the spaces between the vanes
35 define gas ducts 32 for the air flowing into the vane
pack. The dimension of each duct is at a minimum at
the throat 21 defined between the flanges or blades 26
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of one vane and the serrations 24 of an adjacent vane.
The ducts 32, from that point, enlarge further
downstream towards the discharge ends of the vanes.
5 As gas enters the ducts 32 between the vanes it is
deflected by the vanes in the direction of throat 21.
However, the mist particles from the gas tend to move
straight because of their inertia force and so part of
the particles are separated from the gas because they
10 tend to enter the separating chamber. In addition, the
gas stream is deflected around flange 26 into throat 21
where the particles are moved in the radial direction
by centrifugal force and impinge against the concave
surface of the section 18 where they are caught by the
15 serrations 24. These particles, mainly liquid
droplets, then flow down vertically along the
serrations and are removed from the gas stream. As
noted above this structure or mist eliminator vane has
been found to have a very large separation efficiency.
20
As might be expected, because of the deflection of the
air flow and the presence of flange 26, there is a
pressure drop across the vanes as gas moves from the
inlet edges 14 to the outlet edges 22. The pressure
25 drop consumes energy which is needed to force the air
flow through the ducts to keep the air moving properly.
While the profiles with Figure 1 are highly successful
in use, it has been found that there are occasions when
30 particle or mist elimination is not required. For
example, in a gas turbine air inlet cooler in which the
mist eliminator eliminates droplets from the
evaporative cooler section, when the weather is cold
the evaporative cooler is not operated. Thus there is
35 no mist to be eliminated. However, because the mist
eliminator is still present in the air circuit, it is
using up energy unnecessarily. In accordance with the
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present invention, the profile has been constructed to
be collapsible so that the separating chambers 30 are
essentially closed against the profiles themselves and
the wave form of the profile reduced. As a result the
5 pressure drop in the mist eliminator is dramatically
reduced.
Figures 2-4 illustrate one embodiment of the invention.
In this embodiment vanes 10 are formed as two separate
10 vane sections, namely, an inlet or first section 40 and
a second or outlet section 42. Vane section 40 has an
inlet end 14 and an opposite end 44. It includes the
first arc section 16 and part of the second arc section
18. The vane 42 includes the discharge end 22 and an
15 opposite end 46 which is opposed to and faces the end
44 of vane 16. It also includes the third arc section
20 and part of the second arc section 18 as well as
flange or blade 26. The opposed ends 44, 46 of the
first and second vane sections 40-42 are shaped to
20 cooperate with each in order to allow relative pivotal
movement between the two vane sections. In particular,
vane end 44 has a longitudinal pocket 48 formed wherein
while vane end 46 has a longitudinal bead or bar-like
configuration 50 formed therein which is received in
25 pocket 48. This arrangement allows the two vane
sections to pivot relative to one another from the open
position shown in Figure 2 to the position shown in
Figure 3 wherein the separating chamber 30 is closed.
As seen in these figures flange 26 has a free end 54
30 which is located near the pivot point so that, in the
closed position, it overlies a portion of the first
vane section 40 to substantially close separating
chamber 30. The reduction or elimination of the
separating chamber in the configuration shown in Figure
35 3 reduces the pressure drop of air flowing through
ducts 32 between adjacent profiles. As can be seen by
comparing Figures 2 and 3 the deflection of the gases
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flowing in the duct is reduced by this relative pivotal
movement of the profile section.
Figure 4 is an enlarged illustration of one of the mist
eliminator vanes shown in Figures 2 and 3 showing the
open position of the separating chamber 30 in solid
lines and the closed position in dotted lines.
The vanes can be supported adjacent the evaporative
cooler with which they are used in any convenient
manner as would be apparent to those skilled in the
art. In the illustrative embodiment the inlet end 14
of the vanes are supported in recessed vertical bars 60
which have an open pocket 62 that receives the end 14.
15 These bars are in turn fixed to a support structure 64
at the bottom end of the vanes. A similar support
structure (not shown) can be provided at the top edges
of the vanes as viewed in Figure 4. In this embodiment
of the invention the vanes are moved from their open to
20 closed position by the operating mechanism 66. This
mechanism is shown schematically in Figure 4 and can be
altered as desired as would be apparent to those
skilled in the art.
25 In the illustrative embodiment mechanism 66 includes an
operating plate 68 having vertical bars 70 extending
therefrom which are received within the separating
chambers 30 to engage between flange 26 on the convex
side of vane section 18. As will be apparent, there is
30 one bar 70 associated with each of the vanes in the
mist eliminator pack, with all of the bars 70 mounted
on the plate 68 so that they move together.
Plate 68 is mounted in any convenient manner to move
35 from a first position also shown in solid lines in
Figure 4 to a second position shown in dotted lines.
An appropriate guide track mechanism (such as an angled
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slot and pin guide) can be used to guide the movement
of the plate between the two positions shown. Plate 68
is moved from one position to another in any convenient
manner such as for example either manually or by a
5 hydraulic ram 74 or the like. The ram is connected to
the plate in any convenient manner to move the plate in
the appropriate reciprocal motion illustrated in the
drawing. As will be appreciated, when ram 74 is
operated to move plate 68 from its solid line position
10 to its dotted position the separating chamber 30 is
closed.
Figures 5 and 6 illustrate another embodiment of the
invention. In this embodiment the separator vanes 10
15 are formed as one piece integral units, with the first
section 40 being integrally connected to the second
section 42 by a live hinge. As will be understood by
those skilled in the art a live hinge is a reduced
section of thickness in the vane which allows the
20 sections on opposite sides thereof to move or pivot
relative to one another. By this arrangement, the
vanes can move from the position of Figure 5 to
position of Figure 6 to close pocket 30. Alternatively
the hinge portion can be formed by co-extruding a
25 flexible plastic material between first and second
separation vane sections formed of a rigid plastic.
Figure 7 is a pressure graph illustrating a comparison
of the pressure drop within a standard size mist
30 eliminator vane structure between the open and closed
position of the vanes. The solid or "normal" line as
shown Figure 7 represents the pressure drop in inches
of water with the separating chamber open. The thinner
line labeled "folded" shows the pressure drop through
35 the mist eliminator with the same vanes having their
separating chamber in the closed position. This
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difference represents a substantial energy saving when
the mist eliminator is collapsed.
Accordingly, a unique mist eliminator or separator vane
structure has been disclosed which has all of the
advantages of the prior art in terms of efficiency of
particle separation, but which avoids the limitation of
the prior art, i.e., the high pressure losses when mist
elimination is not needed. A simple structure has been
10 developed which allows the vanes to be selectively
moved between positions wherein the vanes will operate
at maximum efficiency for separation when required and
at minimal pressure drop loss when particle separation
is not required.
Although illustrative embodiments of the present
invention have been described here with reference to
the accompanying drawings, it is to be understood that
the invention is not limited to those precise
20 embodiments and that various changes and modifications
may be effected therein by those skilled in the art
without departing from the scope and spirit of this
invention.
