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Fan Selection Application-Based Selection Performance Theory...
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SELECTING THE RIGHT FAN FOR THE JOB This book is designed to help you select the fan that will best fit the application for which it is intended. With the large number of different fan types and sizes available it's necessary to know which fan model does the best job in certain applications and then be able to select the most economical fan size for the job.
INTRODUCTION TO FAN SELECTION This is the first and most basic of this manual’s three belt driven fans different? What types of motors and sections, all of which are designed to enable you to accessories are used with these fans? Are there select the right fan for the job.
Reading Performance Charts The most important part of selecting a fan is the ability exceptions to this rule. The selection procedure for to read the performance charts. Most of the these models is handled separately. Direct drive and performance charts in the catalog are similar and are belt drive fans are also addressed separately.
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One advantage of choosing the GB-101-4-R2 over the GB-101-4-R1 is that it is capable of running at higher rpm’s, which enables the fan to move more air if necessary. Motor pulleys are adjusted by loosening the set screw Belt and turning the top half of the pulley (see illustrations at right).
If the manufacturer you need is not on this Hint: Typically, when matching a Greenheck fan to a chart, contact Greenheck for assistance. competitive model, the size should also be matched. If...
FAN SELECTION BASED ON FAN APPLICATION Basic Overview Fan specification is usually not a precise science and Ventilating a building simply replaces stale or foul air can be done confidently when the fan application is with clean, fresh air. Although the ventilation process is understood.
Commercial Kitchen Ventilation Recommended Exhaust Fans Model CUBE Model USGF Model CWB Model SWB Belt Drive Belt Drive Belt Drive Belt Drive Upblast Roof Exhaust Upblast Roof Exhaust Sidewall Exhaust Utility Blower 300-30,000 cfm 300-7,000 cfm 300-12,000 cfm 500-30,000 cfm Up to 5.0 in.
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Commercial Kitchen Ventilation This drawing shows a commercial kitchen with a typical kitchen ventilation system consisting of a roof mounted CUBE upblast exhaust fan and a Model RSF supply fan. Exhaust fan variations include the model CWB sidewall exhaust fan (also shown) when penetrating the roof is not practical.
General Commercial Ventilation Model G Model CW Direct Drive Roof Exhaust Direct Drive Wall Exhaust 90-3,200 cfm 80-6,000 cfm Up to 1.0 in. wg Up to 2.25 in. wg Model GB Model CWB Belt Drive Roof Exhaust Belt Drive Wall Exhaust 80-44,700 cfm 300-12,000 cfm Up to 3.25 in.
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General Industrial Ventilation Model SB Belt Drive Propeller Sidewall 3,600-85,000 cfm Up to 1.0 in. wg Model RBU Belt Drive Propeller Upblast Model RBUMO 4,000-65,000 cfm Belt Drive Up to 1.0 in. wg Propeller Upblast 3,000-60,000 Up to 1.0 in. wg Model RB RBS-Supply RBE-Exhaust...
High Static Pressure Ventilation Model SWB Belt Drive Utility Blower 500-30,000 cfm Temperatures up to 400°F Up to 5.0 in. wg Model BSQ Belt Drive Inline Fan 150-28,000 cfm Temperatures up to 180°F Up to 4.0 in. wg Typical Applications Models SWB and BSQ are general, all-purpose fans that are capable of moving high air volumes against high static pressures (up to 5.0 in wg).
Determining CFM (cfm) After the model is known, the cfm must be determined. climates and heavier than normal area usage, select a Consult local code requirements or the table below for lower number in the range to change the air more suggested air changes for proper ventilation.
Determining Static Pressure (Ps) The pressures generated by fans in ductwork are very small. Yet, accurately estimating the static pressure is critical to Exhaust Fan proper fan selection. Fan static pressure is measured in inches of water gauge. One pound per square inch is equivalent to 27.7 in. of water gauge.
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Preliminary Selections selecting near the maximum rpm of a size to allow for At this point we know the model, cfm and Ps. With this information we can refer to the GB performance charts final adjustments if necessary. to determine the sizes available to move 2400 cfm There are four GB sizes to choose from in the QD against 0.50 in.
Sound Levels In many cases, the sound generated by a fan must be Suggested Limits for Room Loudness considered. For the fan industry, a common unit for Sones DBA expressing sound pressure level is the sone. In practical terms, the loudness of one sone is equivalent 1.3-4 32-48 Private homes (rural and suburban) to the sound of a quiet refrigerator heard from five feet...
Installation To ensure proper fan performance as cataloged, selected dampers, etc., can cause reduced caution must be exercised in fan placement and performance, excessive noise, and increased connection to the ventilation system. Obstructions, mechanical stressing. For the fan to perform as transitions, poorly designed elbows, improperly published, the system must provide uniform and stable airflow into the fan.
FAN PERFORMANCE The first two sections of this guide contain information The fan curves and system resistance curves below will needed to select the right fan for the particular help to solve fan performance problems that may be application. The information in this section is useful encountered in a variety of applications.
System Resistance Curve Varying System Resistance Curve Sample problem: If a system is designed to move 1000 cfm at a Note: Physically changing the system will alter the resistance of 0.25 in. Ps, what static pressure would the system resistance. For example, closing a fan have to overcome to produce 2000 cfm of airflow? damper from 100% open to only 50% open will add resistance and increase the “steepness”...
Operating Point The operating point of the fan and the system is the point where these two curves intersect. This intersection will determine the cfm and Ps delivered. Varying Operating Points Adjusting Fan Performance There is a direct relationship between cfm and rpm within a system.
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