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Fans
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Order Number
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Title
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Author
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Date
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Field Tests of Fan Performance on Induced Draft Cooling Towers (TPR-122)
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D.D. Herrman
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1962
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Abstract:
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Axial Flow Fans and Their Application to Cooling Towers (TP-36A)
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E.M. Davidson, Hudson Products Corporation
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1968
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Abstract:
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Fan Noise Levels in Cooling Towers (TP-62A)
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W.E. Robb, Chittom Equipment Company
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1969
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Abstract:
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Cooling Tower Fans - Today and Tomorrow (TP-120A)
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Robert C. Monroe, Hudson Products Corporation
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1974
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Abstract:
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Fan Performance Consideration in Cooling Towers (TP-158A)
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David Stackhouse & Kenton Whitehead, Ecodyne Cooling Products Division
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1977
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Abstract:
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Single-Cell Cooling Tower Performance Studies (TP-202A)
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W.R. Brock & J.S. Woodard, Union Carbide, Oak Ridge Gaseous Diffusion Plant
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1979
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Abstract:
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The Effect of Fan Tip Clearance on Cooling Towers Performance (TP-212A)
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Joe M. Schwinn, Ecodyne Cooling Products Division
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1979
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Abstract:
One of the parameters that affect the performance of axial flow
fans of induced draft cooling towers is the clearance between
the tip of the fan blade and the fan stack. Fan performance in
turn influences the behavior of the cooling tower as a whole.
Very little full-scale information is available to indicate the
magnitude of the effect of tip clearance on cooling tower
performance. This paper presents test data taken on actual
cooling tower installations showing the impact of fan tip
clearance on overall tower performance. Such data are helpful in
evaluating the economic trade-off between improved tower
performance and increased costs of a more efficient air movement
system.
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Anomalies in Fan Efficiency Calculations (TP-87-12)
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Weyert E. De Boer, Ventilatoren Stork Hengelo
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1987
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Abstract:
Fan total efficiencies as calculated by the CTI Field Test
Handbook (Chapter 5.5) can, in certain situations, exceed 100%.
This has caused confusion among specifiers and users. Therefore,
efficiencies calculated from experimental data are sometimes
adjusted downward to maintain credibility. The net result is
that fan motor horsepower, as specified, are sometimes higher
than actually needed. The reason for this anomaly is the
incorrect assumption that the static pressure at the fan outlet
is zero. In actuality, it is a negative number due to rotational
flow and turbulence effects. This paper will discuss the problem
and propose corrective action. In addition, the influence of
inlet shape and obstacles will be discussed. Supporting data
will be presented.
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Auto Pitched Fans in Cooling Towers (TP-88-13)
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Charles Chittom, Chittom Int'l
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1988
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Abstract:
This paper is the history of four fan installations, the
problems encountered, if any, and the user satisfaction level.
Different control methods will be shown as well as their
services.
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Hydraulic Cooling Tower Driver the Innovation (TP-88-14)
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John A. Dickerson, Hem, Inc.
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1988
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Abstract:
Expensive fan wrecks and down time occur when motor shaft
couplings break or gearboxes self-destruct. A viable alternative
eliminates shafts, couplings, and gearboxes. The first step is
to move the motors to ground level, which are then close coupled
to a hydraulic pump, which transmits fluid under pressure to a
hydraulic motor at the top of the tower, which directly drives
the fan. Microprocessor controllers can provide inexpensive
energy conservation control at a fraction of the cost of
conventional AC-DC innoverters. The entery aspect alone pays for
the retrofit with the lower maintenance cost an extra bonus.
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The Influence of Materials of Construction on Leading Edge Erosion of Fiberglass Fan Blades Used on Cooling Towers
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Larry F. Burdick, Marley Cooling Tower Company
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1997
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Abstract:
Leading edge erosion is a maintenance concern for fiberglass fan
blades on wet cooling towers. An experiment has been developed
and executed to demonstrate the differences in leading edge
erosion depending on the type of material used in fan blade
construction. The differences in erosion are shown for three
types of fan blades, namely an epoxy resin matrix with and
without an erosion barrier strip and blades molded with vinyl
ester resin having a barrier strip. Both pictorial and weight
loss results are provided for the reader.
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Maximizing Fan Performance
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Robert C. Monroe, Hudson Products Corporation
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1997
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Abstract:
Maximum fan performance usually means maximum airflow for
minimum horsepower, but it also means maximum service life and
sometimes-minimum noise. This paper describes the many points to
consider beginning with selection of an optimum operating point
and many factors concerning the fans operating environment. This
includes tip clearance, obstruction to airflow, vibration, blade
loading, resonant frequency concerns and other important
parameters.
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Noise Testing of Cooling Tower Fan Drives
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Craig Burriss, Amarillo Gear Co.
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1998
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Abstract:
More stringent noise emission requirements and advances in noise
reduction of other cooling tower components are focusing more
attention on the noise emitted by the cooling tower gear drive.
This paper discusses a state-of-the-art test system for
determining noise and vibration characteristics of right angle
cooling tower gear drives. The test system applies torque and
axial thrust loads to simulate actual fan loading conditions.
System capabilities, data collection techniques, and results of
sound power and vibration analysis are presented. The uses of
accurate sound and vibration data to improve gear drive design
and manufacturing methods are discussed. The paper concludes
with a discussion of the expected benefits of this testing to
the cooling tower industry.
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Structural Design Evolution of a Large Fiberglass Fan Blade
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Larry Burdick, The Marley Cooling Tower Company
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1999
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Abstract:
Structural design considerations for large diameter fiberglass
fan blades are an important factor in determining the strength
capability and reliability life of the product. This paper
discusses structural design issues including applied loads,
cross section properties, and stress calculation and strength
verification-methods.
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Advanced Airfoils for Cooling Tower Fan Blades
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James Tangler & Cris Bosetti, National Renewable Energy Lab; Dan Somers,
Airfoils Inc.
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1999
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Abstract:
The objective of this study was to explore the benefits of
advanced airfoil technology for industrial cooling tower fan
blades. An existing fan performance prediction code was used to
identify desirable airfoil characteristics for large
tapered/twisted blades. The Eppler Airfoil design and analysis
Code was then used to design advanced airfoils for the bade root
and tip region. Results show and new airfoils allow a 20%
reduction in blade chord relative to current blades. The
predicted power reduction using the new airfoils was 1% to 2%.
Further power reductions may be realized as a result of lower
cascade flow losses and improved airfoil insensitivity to
roughness effects.
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Evaluation of the Unsteady Loads on a Fan Blade
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Giorgio Cipelletti, Cofimco S.P.A.
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2000
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Abstract:
The knowledge of the unsteady loads is fundamental for the fan
blade fatigue design and for the evaluation of the cooling tower
vibration level. The most significant unsteady loads are
generated by the effect of the aerodynamic interference between
the fan-gearbox supporting beams and the fan blades. This paper
discusses the origin and the effect of the aerodynamic
interference, presents a methodology for calculating the
unsteady loads and the relevant stress on the fan blade, and
shows the experimental results and their correlation with the
theory. A simple method for reducing the unsteady loads is also
discussed.
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Cooling Tower #4, Fan Failure
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Dennis P. Shea, Shelby Sustala, Solutia, Inc.
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2001
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Abstract:
The Chocolate Bayou Plant is a world class chemical plant located in Alvin, Texas about 40 miles
south of Houston. The plant chemical processes are cooled by 3 mechanical draft-cooling towers
with a combined recirculation rate of 267,000 gpm. In March, Cooling Tower 4 experienced a
catastrophic failure of the #8 fan. The root caused investigation indicated serious corrosion
problems with fan equipment, reliability problems with vibration detection system and ineffective
routine inspection on both fan and vibration detection equipment. The root cause analysis recommended
immediate investigation into the mechanical integrity of all plant cooling tower fans and
vibration detection equipment. The results of the system wide investigation resulted in extensive
repairs to existing mechanical fan equipment, repairs to vibration detection systems and
significant changes in preventative maintenance routines.
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A Flexible Blade-to-Hub Connecting System Opposed to a Rigid Element in an Axial Fan.
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Riccardo Provasi, Cofimco S.p.A.
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2002
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Abstract:
Axial fans are subjected to significant loads and vibrations
generated in the blade sections and transmitted to the power
transmission equipment through the hub-to-blade connecting
elements. In the standard configurations fan blades are rigidly
clamped to the hub; in this solution high stress levels occur in
the connecting elements and, generally, in all fan components.
In this paper the influence of the flexibility degree of the
connecting element on the reduction of loads and vibrations is
discussed. Two different solutions are proposed and compared
with standard solution and the results of comprehensive tests on
a large fan are reported.
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Motor Efficiency - A Guide for Reduced Consumption
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John Malinowski Baldor Electric Company
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2003
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Abstract:
This paper will compare motor efficiency levels based on a
Department of Energy survey, EPAct and NEMA Premium™
efficiency levels. It will focus on how a user can reduce the
operating cost of cooling towers by use of premium efficient
motors and adjustable speed drives. Motor purchase price is only
2-4% of the life operating cost of that motor; operating cost
should be considered on any new project. A software tool for
energy surveys and calculations will be introduced.
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Verification of the Benefits of a New Fan Blade Tip Design in a Practical Application
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Sander Venema, Howden Cooling Fans
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2004
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Abstract:
This paper is a continuation of the paper presented last year,
entitled "Vibration Control: New Fan Blade Tip Reduces Pulsation:
(TP03-05). That paper discusses the various vibration modes that can
be generated by the interaction of a fan with the air-cooled
installation. It focuses in particular on the vibration of the fan
stack at blade passing frequency.
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Fan Air Flow Testing on Cooling Towers and ACHEs
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Robert Giammaruti, Hudson Production Corporation
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2005
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Abstract:
Over the past several years, the frequency of fan air flow testing to
verify new or existing fan performances in cooling towers and
air-cooled heat exchangers has increased. Whether for new or
replacement fans, customers want to verify that they are getting all
the performances they were promised by the fan manufacturer - (i.e.
does the fan air flow test meet or exceed what the fan manufacturer
predicted). Proper fan air flow testing, while not an exact science,
can usually spell the difference between a satisfied or unsatisfied
customer. Two fan testing methods - one for wet cooling towers and one
for air cooled heat exchangers - will be discussed in detail as well
as examples given of actual performance versus predicted performance.
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Investigation on Fan Noise Generation and Its Reduction
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Carlo Gallina, Cofimco Srl
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2008
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Abstract:
Nowaday the concept of pollution is involving new aspects of our life and the target given to the industry are getting more and more stringent: noise is one of the most important aspects of the modern pollution.
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Fan Stall Problems; Cause or Effect
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Charles Foster, Diagnostic Cooling Solutions, Inc.
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2008
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Abstract:
The occurance of fan stall appears to be a common factor in an increasing number of cooling tower thermal performance problems. Frequently such problems arise following well intentioned but ill-advised retrofits. Because fan stall is not readily detected, it is often overlooked as a possible sole cause or contributor to performance problems, or as a symptom of other physical or mechanical problems. The mechanism and characteristics of fan stall and discussed in some detail together with detection methods enabling defective cells to be identified and targeted for prioritized repair.
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The Cost of Noise
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Robert Giammaruti, Hudson Products/Cofimco USA
Jess Seawell, Composite Cooling Solutions, L.P.
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2008
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Abstract:
Today, owner/operators, OEM's and suppliers are facing lower and lower near and far field noise limits with respect to their equipment. However, lost in this race to see who can out quiet who is the impact of cost. Specifically, the cost of noise with respect to not only fans, but the fan mechanical and structure parts as well.
This paper will look at two specific applications, one a bank of induced draft-air-cooled heat exchanges and the other being a set of field erected cooling tower cells. In both case studies, the cost of lower and lower near and far field noise will be evaluated with respect to the fan mechanical and structural components.
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Recent Development in Motor Technology Allow Direct Drive of Low Speed Cooling Tower Fans
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Robbie McElveen and Bill Martin, Baldor Electric
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2009
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Abstract:
Improved reliability of cooling tower systems is now possible due to a new development in motor technology. This paper will discuss the development of low speed, permanent magnet motors and how they can be used in direct-drive applications to eliminate the gearbox, NEMA motor, driveshaft, and disc couplings from cooling tower designs. A case study will be presented where an existing tower was refurbished using a direct drive motor which fit the exact footprint and height of the existing gearbox. Design considerations, performance data, maintenance history and efficiency comparisons will be presented.
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Safely Stopping, Holding and Locking Out Cooling Tower Mechanical Sets
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Duane Byerly, Rexnord Industries
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2009
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Abstract:
Safety is becoming an ever increasing factor while working around and inside of cooling towers. When a fan motor is not energized, fans free-wheel from wind and updraft in cooling towers. Entering a fan cell or removing a stack section with the fan rotating is an OSHA violation. Stopping and holding a fan to conduct maintenance operations can be dangerous to personnel. This paper presents methods for stopping and holding fans for maintenance operations and high wind conditions. It will also present various material and mounting options.
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