U.S. patent application number 12/039501 was filed with the patent office on 2009-09-03 for fan shroud for heat exchange tower fans.
This patent application is currently assigned to SPX COOLING TECHNOLOGIES, Inc.. Invention is credited to Michel Vouche.
Application Number | 20090220334 12/039501 |
Document ID | / |
Family ID | 41013310 |
Filed Date | 2009-09-03 |
United States Patent
Application |
20090220334 |
Kind Code |
A1 |
Vouche; Michel |
September 3, 2009 |
FAN SHROUD FOR HEAT EXCHANGE TOWER FANS
Abstract
A heat exchange tower which has at least one fan having fan
blades and a fan shroud, and the fan shroud has a sound absorbing
portion including an outer ring structure and a sound absorbing
material disposed inside the outer ring structure and outside of
the circle of rotation of the fan blades. A flared inlet portion is
provided leading to the sound absorbing portion.
Inventors: |
Vouche; Michel; (Brussels,
BE) |
Correspondence
Address: |
BAKER & HOSTETLER LLP
WASHINGTON SQUARE, SUITE 1100, 1050 CONNECTICUT AVE. N.W.
WASHINGTON
DC
20036-5304
US
|
Assignee: |
SPX COOLING TECHNOLOGIES,
Inc.
|
Family ID: |
41013310 |
Appl. No.: |
12/039501 |
Filed: |
February 28, 2008 |
Current U.S.
Class: |
415/119 |
Current CPC
Class: |
F04D 29/664 20130101;
F04D 29/526 20130101 |
Class at
Publication: |
415/119 |
International
Class: |
F04D 29/66 20060101
F04D029/66 |
Claims
1. A heat exchange tower, comprising: at least one fan having fan
blades with outer tips rotating in a circle of rotation; and a fan
shroud, the fan shroud comprising: an outer ring structure; and a
sound absorbing material mounted to the outer ring surface and
disposed radially inside the outer ring structure and outside of
the circle of rotation of the tips of the fan blades.
2. The heat exchange tower of claim 1, wherein the fan shroud
comprises a flared inlet portion leading into the outer ring
structure.
3. The heat exchange tower of claim 2, wherein the inlet portion is
integral with the outer ring structure.
4. The heat exchange tower according to claim 1, further comprising
an inner structure that sandwiches the sound absorbing material
between the inner structure and the outer ring structure.
5. The heat exchange tower according to claim 4, wherein the inner
structure comprises a metal screen.
6. The heat exchange tower according to claim 1, wherein the outer
ring comprises a plurality of arcuate sections.
7. The heat exchange tower according to claim 1, wherein the outer
ring comprises at least one C-shaped arcuate metal band.
8. The heat exchange tower according to claim 1, wherein the outer
ring comprises at least one molded fiberglass arcuate section that
forms at least one pocket that receives the sound absorbing
material.
9. The heat exchange tower according to claim 1, wherein the sound
absorbing material is fiberglass batting.
10. The heat exchange tower according to claim 1, wherein the sound
absorbing material is foam.
11. The heat exchange tower according to claim 4, wherein the outer
ring comprises at least one C-shaped arcuate metal band.
12. The heat exchange tower according to claim 4, wherein the outer
ring comprises at least one molded fiberglass arcuate section that
forms at least one pocket that receives the sound absorbing
material.
13. The heat exchange tower according to claim 4, wherein the sound
absorbing material is fiberglass batting.
14. The heat exchange tower according to claim 4, wherein the sound
absorbing material is foam.
15. A heat exchange tower, comprising: at least one fan having fan
blades with outer tips rotating in a circle of rotation; and a fan
shroud, the fan shroud comprising: an outer supporting means; and a
sound absorbing means mounted to the outer supporting means
disposed radially inside the outer supporting means and outside of
the circle of rotation of the tips of the fan blades.
16. The heat exchange tower of claim 15, wherein the fan shroud
comprises a flared inlet portion leading into the outer supporting
means.
17. The heat exchange tower according to claim 15, further
comprising an inner supporting means that sandwiches the sound
absorbing material between the inner and the outer supporting
means.
18. A heat exchange tower, comprising: at least one fan having fan
blades with outer tips rotating in a circle of rotation; and a fan
shroud, the fan shroud comprising: an outer ring structure formed
of at least one molded section, the section forming at least one
pocket; and a sound absorbing material disposed inside the pocket
and radially outside of the circle of rotation of the tips of the
fan blades.
19. A heat exchange tower according to claim 18, wherein the molded
section includes at least two axially spaced pockets separated by a
rib in between the pockets, with sound absorbing material disposed
in each pocket.
20. A method for reducing sound emitted by a heat exchange tower,
the tower having at least one fan blade with outer tips rotating in
a circle of rotation, and a fan shroud surrounding the circle of
rotation of the tips, comprising the step of: providing a sound
absorbing material on an inner surface of the shroud between the
inner surface of the shroud and the circle of rotation of the blade
tips.
21. An air cooled condenser, comprising: a plurality of condenser
coils; a fan deck disposed below the condenser coils, the fan deck
comprising a plurality of fans having fan blades with outer tips
rotating in a circle of rotation, and a plurality of fan shrouds
each surrounding a respective fan, each fan shroud comprising: an
outer ring structure; and a sound absorbing material mounted to the
outer ring surface and disposed radially inside the outer ring
structure and outside of the circle of rotation of the tips of the
fan blades.
Description
FIELD OF THE INVENTION
[0001] The invention relates to the field of heat exchange towers,
and more particularly relates to the field of fans used to move air
through heat exchange towers, including industrial cooling towers,
industrial heating towers, and air cooled steam condensers.
BACKGROUND OF THE INVENTION
[0002] A wide variety of heat exchange towers are known in the
industry. These heat exchange towers include, for example,
so-called industrial cooling towers, which are used to cool warm
water by industrial or other processes. These cooling towers
typically have a liquid that is sprayed from a top inside the
tower, and falls over a media such as, for example, splash bars or
a pack of spaced apart thin film sheets. Air is typically drawn
through the tower, either sideways across the tower, upwardly
through the tower, or a combination thereof, and interacts with the
falling liquid. The falling liquid is warmer than the ambient air,
and thus is cooled by this process and falls into a collection
basin at the bottom of the tower. Another type of heat exchange
tower is a heating tower which may be used, for example, for the
vaporization of liquefied natural gas.
[0003] Yet another type of tower is an air cooled condenser (ACC)
tower. Such a tower is typically a large box-like structure having
an open lower or side frame. The open frame may be closed off on
some of its sides. The frame supports a deck having a series of
fans which blow air upward so that the air is drawn in through the
open sides of the tower and is forced upward by the fans. Above the
fans the tower supports a series of condenser coils. In some
examples, a plurality of steam supply header tubes run lengthwise
on the top of the tower and dispense steam downward into angled
downwardly extending condenser coils. Water is heated in a boiler
to create steam, which is then sent to a high pressure end of a
turbine to create work (via change in energy of the steam). The
steam at the low pressure end of the turbine then is condensed by
the condenser to create a vacuum that pulls the steam through the
turbine. At the bottom of the angled downwardly extending condenser
coils is a series of collection header tubes which receives
condensed fluid and exits it from the tower. The entirety of the
condenser coils is usually located above the fans. Air is exhausted
out the open top of the tower past the steam supply header tubes. A
deck of the fans is added below the coils to provide a greater
volume of air flow. The deck typically has a number of fans spaced
in a grid-like arrangement, each surrounded by a fan shroud. Other
terms for fan shroud are fan inlet bell or fan casing. An example
of a different ACC tower is described in U.S. Patent Publication
No. 2006/0243430.
[0004] All of the above types of towers are suitable for various
applications and have found wide acceptance in industry. However,
it is often desirable in such tower installations to reduce the
noise or sound that is produced by the tower. One major cause of
noise or sound in some towers is noise that is generated by the
operation of the fans themselves. In the case of ACCs, a relatively
large number of fans is often present, and thus the desire to
reduce the noise associated with each fan is sometimes even greater
than with other types of heat exchange towers.
SUMMARY OF THE INVENTION
[0005] In one aspect, a heat exchange tower comprises at least one
fan having fan blades with outer tips rotating in a circle of
rotation, and a fan shroud, the fan shroud comprising an outer ring
structure, and a sound absorbing material mounted to the outer ring
surface and disposed radially inside the outer ring structure and
outside of the circle of rotation of the tips of the fan
blades.
[0006] In another aspect, a heat exchange tower also comprises at
least one fan having fan blades with outer tips rotating in a
circle of rotation, and a fan shroud, the fan shroud which has an
outer supporting means and a sound absorbing means mounted to the
outer supporting means disposed radially inside the outer
supporting means and outside of the circle of rotation of the tips
of the fan blades.
[0007] In yet another aspect, a heat exchange tower has at least
one fan having fan blades with outer tips rotating in a circle of
rotation and a fan shroud, the fan shroud comprising an outer ring
structure formed of at least one molded section, the section
forming at least one pocket and a sound absorbing material disposed
inside the pocket and radially outside of the circle of rotation of
the tips of the fan blades.
[0008] Another aspect provides a method for reducing sound emitted
by a heat exchange tower, the tower having at least one fan blade
with outer tips rotating in a circle of rotation, and a fan shroud
surrounding the circle of rotation of the tips, comprising the step
of providing a sound absorbing material on an inner surface of the
shroud between the inner surface of the shroud and the circle of
rotation of the blade tips.
[0009] Still another aspect provides an air cooled condenser which
has a plurality of condenser coils, a fan deck disposed below the
condenser coils, the fan deck comprising a plurality of fans having
fan blades with outer tips rotating in a circle of rotation, and a
plurality of fan shrouds each surrounding a respective fan, each
fan shroud comprising an outer ring structure; and a sound
absorbing material mounted to the outer ring surface and disposed
radially inside the outer ring structure and outside of the circle
of rotation of the tips of the fan blades.
[0010] There has thus been outlined, rather broadly, certain
embodiments of the invention in order that the detailed description
thereof herein may be better understood, and in order that the
present contribution to the art may be better appreciated. There
are, of course, additional embodiments of the invention that will
be described below and which will form the subject matter of the
claims appended hereto.
[0011] In this respect, before explaining at least one embodiment
of the invention in detail, it is to be understood that the
invention is not limited in its application to the details of
construction and to the arrangements of the components set forth in
the following description or illustrated in the drawings. The
invention is capable of embodiments in addition to those described
and of being practiced and carried out in various ways. Also, it is
to be understood that the phraseology and terminology employed
herein, as well as the abstract, are for the purpose of description
and should not be regarded as limiting.
[0012] As such, those skilled in the art will appreciate that the
conception upon which this disclosure is based may readily be
utilized as a basis for the designing of other structures, methods
and systems for carrying out the several purposes of the present
invention. It is important, therefore, that the claims be regarded
as including such equivalent constructions insofar as they do not
depart from the spirit and scope of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic perspective view of an air cooled
condenser having a fan deck with a plurality of fan shrouds.
[0014] FIG. 2 is a bottom view of a fan surrounded by a fan
shroud.
[0015] FIG. 3 is a sectional view of a fan and a fan shroud taken
through line 3-3 in FIG. 2, according to the first preferred
embodiment of the invention.
[0016] FIG. 4 is a detailed view of a fan shroud taken through the
detail circle of FIG. 3.
[0017] FIG. 5 is a slightly cutaway perspective view of the fan
shroud.
[0018] FIG. 6 is a cutaway perspective view of the fan shroud shown
in FIG. 5.
[0019] FIG. 7 is a somewhat exploded view of a fan shroud according
to a second preferred embodiment of the invention.
[0020] FIG. 8 is a cutaway detail view of the fan shroud of FIG.
7.
DETAILED DESCRIPTION
[0021] Some embodiments of the present invention provide a fan
shroud for heat exchange tower fans, including a noise reducing
material that can reduce fan noise coming from the heat exchange
tower. In some embodiments, the fan shroud includes an outer ring
structure and the sound absorbing material is disposed inside the
outer ring structure and outside the circle of rotation of the tips
of the fan blades. Some preferred embodiments of the invention will
now be described with reference to the drawing figures, in which
like reference numerals refer to like parts throughout.
[0022] Turning now to FIG. 1, an air cooled condensing (ACC) tower
10 is shown. The tower includes a base 12 which rests on the ground
and lower framework 14 which supports a fan deck 16. The lower
framework 14 is shown simply as being legs at the corner of the
tower. However, it will be appreciated by one skilled in the art
that such a frame 14 is typically an internal lattice framework
having columns and girts interconnected with each other to form an
open frame. All four sides of the frame may be left open below the
fan deck 16, or in some instances two of the opposed sides may each
have a closed wall. Examples of an ACC illustrated herein will be
described in the context of having the two end walls labeled 18 and
19 as being closed and the two sides labeled 20 and 21 as being
open. However, it will be appreciated may have any number of open
or closed sides beneath the fan deck 16.
[0023] The fan deck 16 is a support structure which typically
supports a plurality of individual fans 24 (blades not shown in
FIG. 1 for clarity of illustration), each having their own fan
shroud 26 associated therewith. The fan shrouds 26 are discussed in
further detail below. The fans 24 blow air upward past a series of
angled condenser tube coil structures 28. The coils 28 are
elongated coils generally forming a planar sheet-like structure
which air can pass through. The coils 28 receive steam from a
plurality of steam supply headers 30. The steam supply headers lead
into the coils 28 and steam/water falls downward vertically through
the coils 28 and is cooled by heat exchange with the ambient air
outside the coils 28. The steam condenses into water which is
collected in lower water collection headers 32 and discharged from
the tower.
[0024] An upper frame structure 40 is typically provided to provide
overall structural support to the area having the supply headers
30, condenser coils 28, and water headers 32. The coil and header
pieces build into an upper superstructure. The frame structure 40
is simply framing for the casing. The casing may extend to
approximately the bottom of the steam header or may extend some
modest distance above the steam header. This upper frame 40
typically will have all four sides closed by solid or generally
non-porous side walls or coverings 42 on all four sides. It will be
appreciated that in FIG. 1 many solid items such as the side walls
are shown being transparent so that an inner view of the tower 10
can be provided.
[0025] FIGS. 2-6 show a first preferred embodiment of the present
invention. In this embodiment the fan shroud 26 includes an eased
or flared, inwardly tapered inlet section 102, as well as a noise
absorbing section 104, which is disposed at the axial position of
the fans, and surrounds the fan tips as they rotate.
[0026] The noise absorbing section 104 is adapted to reduce sound
coming from the fan tips in particular, and the fan in general. The
eased or flared inlet section 102 may be of a relatively
conventional construction and can be, for example, made of segments
of molded fiberglass material, or may be in sections or a
continuous piece of rolled steel. The noise absorbing section 104
includes as some portion thereof a sound absorbing material 114.
Various arrangements for mounting the sound absorbing material 114
are discussed further herein. Sound absorbing materials may
comprise any known or future discovered sound absorbing material,
such as, for example, fiberglass batting or foam. Also, the sound
absorbing material may comprise an irregular shaped surface
material. By way of example, only some suitable materials include
acoustical foam such as that made by SONEX.RTM., or open and closed
all flexible polyurethane, polyimide, melamine and other absorption
foams, or flexible external viscoelastic and constrained layer
products available from SOUNDCOAT.RTM.. Simple fiberglass batting
such as used for insulation is also suitable. Also, besides the
above and other passive materials, locally active materials may be
employed. Combinations of different sound absorbing materials may
also be used. Further, the sound absorbing material may span
entirely around the circumference of the noise absorbing portion
104, may span across arcuate portions of the noise absorbing
portion 104, and may span either part of the entire height of the
noise absorbing portion 104. Further, although the noise absorbing
portion 104 is referred to herein for convenience as having a
straight side, it may of course also have either or both of its
inner and outer surfaces being a somewhat convex, or somewhat
concave shape, or may have an undulating shape. Further, the noise
absorbing portion 104 may simply be a truncated cone flaring in
either the upwards or downwards direction, or a combination of
outward and upward flaring cones.
[0027] Turning now particularly to FIGS. 4 and 5, the noise
absorbing section 104 is illustrated as further having an outer
ring 106, which has a straight C-shaped cross section and may be
formed by a rolled steel cylinder having a straight sided outer
wall 108 and top and bottom walls 110 and 112. The arrangement also
features a thickness of sound absorbing material 114, which in one
preferred embodiment may be fiberglass batting. As discussed
herein, the sound absorbing material 114 may be other materials
such as foam or a material having a complex reflective or absorbing
surface finish. Also, combinations of various sound absorbing
materials may be used to make up the sound absorbing material
114.
[0028] In the illustrated embodiment, an inner screen 120 is
provided inside of the location of the sound absorbing material
114. The screen 120 is at least somewhat permeable to sound so that
the sound will be absorbed by the sound absorbing material 114, and
further can provide structural support to retain the sound
absorbing material 114 in place. In this embodiment, a steel screen
is used having 20 to 50 per cent open area. Examples of suitable
screens include metal or plastic plate perforated with holes or
slots, or metal or plastic mesh. In the case of a sound absorbing
material 114 that loses its integrity when subjected to airflow,
vibration and/or moisture, the screen 120 serves the function of
retaining the sound absorbing material 114 in its place, so that it
does not tend to shred or come apart. The screen 120 also reduces
the moisture that will enter the sound absorbing material 114 in
the case of, for example, rain falling into the fan shroud.
Additionally, a water resistant membrane may be placed between
screen 120 and sound absorbing material 114. A water resistant
membrane example is Gore-Tex.RTM. material. In the embodiment as
depicted in FIGS. 3-5, the overall fan shroud 26, including the
sound absorbing material features, is supported from above by a fan
deck 16 by using conventional support arrangement.
[0029] FIG. 6 shows the outer ring 106 in combination with the
screen 120 forming a hollow pocket 122. In FIG. 6 the
sound-absorbing material 114 is not shown. FIG. 6 also shows that
the outer ring 106 can be made of a number of rolled boxed curved
steel segments, which can be joined by virtue of flanges 124 that
accept bolts into neighboring flanges of the neighboring arcuate
sections. FIG. 6 also illustrates a flange 126 provided along the
bottom of the ring 106, which can facilitate joining with the
flared inlet portion 102.
[0030] FIGS. 7 and 8 illustrate a second embodiment which utilizes
the principles of the first embodiment described above, but adds
some variations and additional features. For example, in the
embodiment of FIG. 7, a flared inlet section 202 is integral with
the outer ring of the noise absorbing section 204. Thus, an entire
shroud is formed by a plurality of arcuate sections with each
section having a lower flared portion 204 and an upper outer ring
of a sound absorbing portion 204. In the example of FIG. 7, the
entire shroud is made of a plurality of arcuate sections. In this
example, each arcuate section has been molded from fiberglass
material. Joining flanges 224 are provided, and can be bolted to
each other. In the case of fiberglass construction, intermediate
steel plates re-enforcements may be bolted to be sandwiched in
between the neighboring flanges 224.
[0031] Turning further to the sound absorbing portions 204 in the
embodiment of FIGS. 7 and 8, it will be appreciated that each
section forms part of the sound absorbing portion 204 and has one
or more pockets 222 that are molded directly into the structure. In
the example of FIGS. 7 and 8, two elongated pockets 222 are molded
one above the other. This provides an intermediate rib structure
223 between the pockets 222 which can enhance the stiffness of the
sections.
[0032] As with the previous embodiment discussed above, a screen
220 is provided forming part of the inner surface of the fan
shroud. Disposed between the screen 220 and the pockets 222 are
sound absorbing material 214. As illustrated in FIG. 7, the sound
absorbing material 214 includes segments of fiberglass batting 208.
The fiberglass batting 208 tends to absorb sound. Although
fiberglass batting is discussed with respect to the second
embodiment, any other sound absorbing material or a combination of
materials may be employed. In the embodiment of FIGS. 7 and 8, the
screen may be attached by screws 232 screwed into the ring
structure 204.
[0033] The above-described examples show structures that can reduce
the sound emitted by a fan deck in an ACC. Aspects of these
embodiments can also be applied to other heat exchange tower
fans.
[0034] The many features and advantages of the invention are
apparent from the detailed specification, and thus, it is intended
by the appended claims to cover all such features and advantages of
the invention which fall within the true spirit and scope of the
invention. Further, since numerous modifications and variations
will readily occur to those skilled in the art, it is not desired
to limit the invention to the exact construction and operation
illustrated and described, and accordingly, all suitable
modifications and equivalents may be resorted to, falling within
the scope of the invention.
* * * * *