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Fan Laws and System Curves - The
purpose of this Engineering Letter is to explain the basis and application of
the rules used to predict fan performance in a given system. With a basic
understanding of these rules, the performance of a fan can be quickly calculated
for various conditions.
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Increasing Fan Performance -
Industrial process and plant-ventilation systems often need more air than
originally designed. Increased production requirements, process changes, and
facility renovations are a few of the major reasons. Additionally, the lack of
adequate maintenance over time can negatively impact system airflows. This
letter discusses several procedures that can increase air flow.
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Pneumatic Conveying - A well
designed pneumatic conveying system is often a more practical and economical
method of transporting materials from one point to another than alternative
manual or mechanical systems. This Engineering Letter outlines some of the
fundamental principles of pneumatic conveying systems and explains various
special considerations for fan selection.
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Screw Machines - Screw machines
produce finished metal products from round stock. The stock is fed to the
machine automatically from a magazine-fed stock reel and held in position by
collets. Screw machines cycle automatically finishing a part each time the
machine indexes. Learn More...
System Calculation - A fan system
is any combination of ductwork, hoods, filters, louvers, collectors, etc., that
relies upon a fan to produce airflow. When the air moves past each of these
components, resistance is created which must be considered in system
calculations. It is also important to remember that fans are rated independently
of a system and that fan performance will vary depending upon the accuracy of
the system calculations. This Engineering Letter will explain some of the basic
fundamentals of system design and calculation.
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Fan Performance - The System
Effect - Fans are typically tested and rated in prescribed test configurations
defined by the Air Movement and Control Association. This is done to ensure
standardized procedures and ratings so that system designers can make realistic
choices among various manufacturers. Beyond the routine system resistance
calculations, the location of some of the common components and their proximity
to the fan inlet or outlet can create additional immeasurable losses commonly
called System Effect. These losses, if not eliminated or minimized, will
necessitate fan speed and horsepower increases to compensate for the performance
deficiencies. This Letter will outline some of the common causes for these
deficiencies and provide useful guidelines for more efficient and predictable
air-handling systems. Learn More...
Understanding Fan Performance Curves
- One of the most important documents customers request from fan manufacturers
is performance curves. In addition to graphically depicting the basic fan
performance data of CFM, RPM, and SP (on the static pressure curve) and BHP (on
the brake horsepower curve), these curves also illustrate the performance
characteristics of various fan types, like areas of instability, or the rate of
change between flow and pressure. With some basic knowledge of performance
curves, decisions can be made concerning fan selection, fan and system
alterations, or the advisability of using a fan in a modulating system, for
example.
Except for very large fans, performance curve
information is generated by connecting the fan to a laboratory test chamber.
Very specific test procedures are followed as prescribed in the Air Movement and
Control Association's Standard 210 to assure uniform and accurate readings. Data
points are collected at a given RPM while the flow is slowly modulated from full
close to full open. The information gathered is then used to develop computer
selection programs and published capacity tables for use by system designers
and end users. Learn
More...
White Papers
How to diagnose and solve ducting problems in your dust
collection system (Steven
A. Bradbury, Darren Wood, and Garren E. Tooker - Air Control Science)-
"Plants that handle bulk solids rely on dust collection systems
not only to keep the workplace clean and healthy for workers, but to protect
equipment and other valuable assets from fires and explosions. Yet more often
than not, these dust collection systems underperform, leading to an unhealthy
work environment, expensive ongoing maintenance, and premature equipment
failure. This article explains how to diagnose problems with your dust
collection system’s ducting system, a common trouble source. Sections explain
how poor design, fabrication, and installation can lead to these problems and
what you can do to remedy them."
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Designing your dust collection system to meet NFPA
standards - Part I (Gary Q. Johnson - Workplace Exposure
Solutions)- "Plants that handle bulk solids
rely on dust collection systems not only to keep the workplace clean and healthy
for workers, but to protect equipment and other valuable assets from fires and
explosions. Yet more often than not, these dust collection systems underperform,
leading to an unhealthy work environment, expensive ongoing maintenance, and
premature equipment failure. This article explains how to diagnose problems with
your dust collection system’s ducting system, a common trouble source. Sections
explain how poor design, fabrication, and installation can lead to these
problems and what you can do to remedy them."
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Value in the Air - Why Direct Drive Backward Curved
Plenum Fans? (AAON)- "AAON
equipment has been designed and engineered for both performance and energy
efficiency. From standard equipment designs to complex heating and cooling
systems, AAON provides performance and energy efficiency solutions for virtually
all applications. Fans are one of the most important components of any HVAC
(Heating, Ventilating and Air Conditioning) system in terms of performance and
energy efficiency. Direct drive, backward curved plenum fans are the optimum
choice for practically all commercial HVAC applications. The following
information will show the many reasons why.
First, the basics of fans, fan curves and fan
laws will be introduced. Next, fan selection will be covered, including points
of operation, fan widths and variable speed operation fans. Fan system effects
will then be covered including inlet, discharge, belt and plenum fan discharge
system effects. Then fan efficiency and unit efficiency will be summarized.
Finally, an overview of AAON direct drive plenum fans will conclude the
information. References for the information provided are available on the final
page." Learn More...
Factors Affecting Fan Selection
(Industrial Air Technology Corp.)
- Presented in a
chart
here...
Keep Plant Air Quality High -
(DSHAY AirSystems, Inc.) - "With the variety of
contaminants that exist in most manufacturing plants, a single type of
filtration system or filter medium seldom is universally effective. However,
once the materials and processes used in the operation are known, types of
pollutants in the air can be identified and an effective air filtration system
designed to improve plant indoor air quality."
Learn More...
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