MULTI-WING AMERICA, INC.
A Crowley Company
ISO 9001-2000
GENERAL ENGINEERING GUIDE. The Multi-Wing® System. • • • • •
Interchangeable components Application versatility Choice of blade designs Five corrosion-resistant blade materials Tailored for the application
More Information: Multi-Wing Specifications Performance Factors Variable Factors Application Assistance Fan Selection Guide Multi-Wing Home
P.O. Box 425 • 15030 Berkshire Industrial Parkway • Burton, Ohio 44021 • Toll Free: 800-311-8465 • Phone: 440-834-9400 • Fax: 440-834-0449 • Web Site: www.mw-america.com • E-Mail:
[email protected]
MULTI-WING AMERICA, INC.
A Crowley Company
ISO 9001-2000
PERFORMANCE ENGINEERED MULTI-WING FANS. ®
The Multi-Wing 8 Series System Design Matrix
8W Series Fan
8D Series Fan
8X Series Fan
8M Series Fan
8D
8M
8W
8X
Blade Profile
twisted paddle
twisted paddle
broad blade
twisted paddle
Blades
2 or 4
4
3-5
3-5
Diameter
12"-26"
10"-20"
24"-48"
36"-68"
Angles
fixed pitch 25˚-40˚
one piece molded 30˚-40˚
adjustable pitch 15˚-45˚
adjustable pitch 20˚-45˚
HVAC
HVAC
HVAC
HVAC
Fan Series
Application
The Multi-Wing system uses standard, interchangeable components which can be custom modified to specific requirements. Component standardization means fast deliveries and no minimum order quantities or set-up charges. Multi-Wing Fans feature cast aluminum hubs and a variety of high performance blade designs molded in engineered thermoplastics or die cast aluminum. This gives them both low weight and high strength, enabling them to be used successfully in thousands of air-moving applications worldwide, ranging from engine cooling to ventilation.
Design Features Include: • System of interchangeable components + Customized fans: number of blades, pitch angles, diameters and blade materials + Off-the-shelf prices
• Versatility—can be used in all types of environments from HVAC to engine cooling + Severe duty applications + High vibration applications • Blade designs to meet your performance demands + High efficiency airfoil profile blades + Low speed broad paddle blades + Poor inlet resistant increasing arc profile blades • Blade materials to meet your application requirements + Glass reinforced polypropylene + Glass reinforced nylon + Electro anti-static nylon + “Super Tuff” nylon + Die cast aluminum
The Multi-Wing System Design Matrix
• Configured to meet your specific requirements + Any diameter from 7 to 78 inches + Fans with 2 to 16 blades + Standard and special mounting + Special coatings for corrosion resistance + Thermoplastic hubs available
H Series Fan
6Z Series Fan Fan Series
Z Series Fan
Aluminum H & Z Series Fans
W Series Fan
All-Plast Series Fan
H
Z
W
6Z
Aluminum
All-Plast
Blade Profile
twisted airfoil
twisted airfoil
twisted airfoil
increasing arc
twisted airfoil
twisted airfoil
Blades
2-14
3-16
3-10
3-16
2-16
2-8
Diameter
7"-29"
16"-49"
36"-78"
24"-49"
7"-60"
7"-30"
Angles
fixed pitch 25˚-45˚
adjustable pitch 20˚-50˚
adjustable pitch 25˚-50˚
adjustable pitch 20˚-35˚
adjustable or fixed pitch 20˚-50˚
adjustable or fixed pitch 20˚-45˚
industrial HVAC
industrial HVAC
industrial HVAC
off highway
industrial HVAC
cooling ventilation
Application
Performance Factors Variable Factors Application Assistance Fan Selection Guide Multi-Wing Home
P.O. Box 425 • 15030 Berkshire Industrial Parkway • Burton, Ohio 44021 • Toll Free: 800-311-8465 • Phone: 440-834-9400 • Fax: 440-834-0449 • Web Site: www.mw-america.com • E-Mail:
[email protected]
MULTI-WING AMERICA, INC.
A Crowley Company
ISO 9001-2000
Multi-Wing Specifications Variable Factors Application Assistance Fan Selection Guide Multi-Wing Home
PERFORMANCE FACTORS. Comparative Performance for Various Inlet Conditions
Pressure
Bell Mouth Flat Plate
Volume
Influence of Tip Clearance on Performance
Pressure
0.5% 1.0% 2.0% 3.0%
Volume
Recommended Mounting for Inlet Conditions. In general, the best operating results are obtained when the incoming air flow has a smooth entry to the fan. This is best achieved by mounting the fan in a bell mouth opening (see figs. 1 and 2). The bell mouth opening reduces the turbulence associated with moving air, increasing fan efficiency and reducing noise. The optimum bell radius is r/d = .12, where r is the radius of the bell and d is the fan diameter. In applications where this ratio may be impractical, an r/d range of .07 to .12 is recommended. Many applications utilize a sharp-edge orifice, such as a hole in flat sheet metal. While this is not the most efficient method, it can work satisfactorily if the fan is positioned within the orifice and a 2.5 percent or less tip clearance is maintained (see fig. 3).
Tip Clearance.
Optimal Shroud Placement.
In all applications the fan will perform at its highest efficiency when the tip clearance is 1 percent of the fan diameter. In those cases where this may not be practical, a range of 1 to 2.5 percent tip clearance is recommended.
AIR FLOW
FIG.1
Deep Bell Mouth Entire blade is covered by flat area of the venturi. FIG.2
Shallow Bell Mouth
Fan performance significantly decreases as tip clearances exceed 2.5 percent.
AIR If it is not possible to cover the FLOW entire blade with the flat portion of the venturi, then the leading edge and as much of the fan as possible should be covered. Make sure the leading edge does not extend into the bell portion of the venturi. AIR FLOW
FIG.3
Sharp Edge Orifice The leading edge and two-thirds of the fan should protrude on the air intake side of the opening.
FIG.4
30° Inlet
AIR FLOW
The leading edge and two-thirds of the fan should protrude on the air intake side of the opening.
30°
P.O. Box 425 • 15030 Berkshire Industrial Parkway • Burton, Ohio 44021 • Toll Free: 800-311-8465 • Phone: 440-834-9400 • Fax: 440-834-0449 • Web Site: www.mw-america.com • E-Mail:
[email protected]
MULTI-WING AMERICA, INC.
A Crowley Company
ISO 9001-2000
VARIABLE FACTORS. Standard Correction Factor Table Altitude Pressure (Hg)
0'
500'
1000'
1500'
2000'
2500'
3000'
3500'
4000' 4500' 5000'
29.92 29.38
28.86
28.33
27.82
27.31
26.82
26.32
25.84 25.36 24.90
Temp. ˚F -40 0 40 70 80 100 120 140 160 180 200 250 300 350 400
.79 .87 .94 1.00 1.02 1.06 1.09 1.13 1.17 1.21 1.25 1.34 1.43 1.53 1.62
.82 .90 .98 1.04 1.06 1.10 1.13 1.17 1.21 1.25 1.29 1.39 1.49 1.58 1.68
.84 .92 1.00 1.06 1.08 1.12 1.16 1.20 1.24 1.28 1.32 1.41 1.51 1.61 1.71
.85 .93 1.01 1.08 1.10 1.14 1.18 1.22 1.26 1.30 1.34 1.44 1.54 1.64 1.75
.87 .95 1.03 1.10 1.12 1.16 1.20 1.24 1.28 1.32 1.36 1.47 1.57 1.67 1.78
.88 .97 1.05 1.12 1.14 1.18 1.22 1.26 1.31 1.35 1.39 1.49 1.60 1.70 1.81
.90 .99 1.07 1.14 1.16 1.20 1.24 1.29 1.33 1.37 1.42 1.52 1.63 1.74 1.84
.92 1.00 1.09 1.16 1.18 1.22 1.27 1.31 1.35 1.40 1.44 1.55 1.66 1.77 1.88
.81 .88 .96 1.02 1.04 1.08 1.11 1.15 1.19 1.23 1.27 1.36 1.46 1.56 1.65
.93 1.02 1.11 1.18 1.20 1.25 1.29 1.34 1.38 1.42 1.47 1.58 1.69 1.80 1.91
.95 1.04 1.13 1.20 1.22 1.27 1.31 1.36 1.41 1.45 1.50 1.61 1.72 1.84 1.95
A fan blade is a constant volume machine, which means that a fan can move a volume of air at sea level and the same volume at 5000 feet above sea level. The difference is that the fan can move the air volume at a higher pressure level operating at sea level than it can at 5000 feet above sea level. This is due to the density of the air at the operating conditions. In addition, the power required to operate the fan will vary due to air density. Therefore, when working with fan curves at standard operating conditions (70° F and sea level), it is important to correct your actual conditions back to standard in order to be sure you are making the proper selection.
Altitude & Temperature Calculations Example: Required performance 10000 cfm 0.50 inWG static pressure 5000 feet elevation 200 degrees F. You are
working with curves where the performance is measured at standard operating condition (70° F and sea level) Factor calculation 0.50 x 1.50 (factor from table) = 0.75 inWG Ps The fan will have to produce 10000 cfm at 0.75 inWG Ps at standard operating conditions in order to provide the required performance at the actual operating conditions.
Power Calculations To determine the power required to operate the fan at condition other than standard, divide the power required at standard conditions, by the factor for temperature and elevation at your actual conditions.
and 200O F. Caution should be exercised when using this formula, fans sized for extreme summer conditions may cause motors to overload at extreme winter conditions. The fan motor should be sized for the highest density factor in which the fan may operate.
Air Flow Testing. Air flow measurements for Multi-Wing Fans are conducted in our wind tunnel. The fans are tested in accordance with AMCA Standard 210 Figure 12, outlet chamber method— multiple nozzles in the chamber. The fans are tested in a bell mouth venturi with a total tip clearance of 1% of the fan diameter.
Blade Material Specifications. Blade Material
Example: 5.0 (Power from curves) / 1.50 (factor from table) = 3.33 hp required to operate the fan at 5000 ft
Symbol
Temperature Range
Application Duty
Glass Reinforced Polypropylene
PPG
-40˚ F to +185˚ F
Standard Duty
Glass Reinforced Nylon
PAG
-50˚ F to +250˚ F
Heavy Duty, Engine Driven
“Super Tuff” Nylon
PAGST
-50˚ F to +250˚ F
Extreme Vibration
Electro Anti-Static Nylon
PAGAS
-40˚ F to +250˚ F
Hazardous Conditions
Die Cast Aluminum
AL
-60˚ F to +300˚ F
Temperature Extremes
All materials are corrosion resistant and spark proof on impact. PAGAS blades are suitable for underground mining, oil and gas platforms, chemical processing plants, or any application where there is potential for explosion.
Multi-Wing Specifications Performance Factors Application Assistance Fan Selection Guide Multi-Wing Home
For severe duty corrosive applications, pressure die cast aluminum hubs and plastic hubs can be supplied with protective coatings and stainless steel fasteners.
P.O. Box 425 • 15030 Berkshire Industrial Parkway • Burton, Ohio 44021 • Toll Free: 800-311-8465 • Phone: 440-834-9400 • Fax: 440-834-0449 • Web Site: www.mw-america.com • E-Mail:
[email protected]
MULTI-WING AMERICA, INC.
A Crowley Company
ISO 9001-2000
Multi-Wing Specifications Performance Factors Variable Factors Fan Selection Guide Multi-Wing Home
APPLICATION ASSISTANCE. Our technical specialists evaluate and adjust performance parameters like airflow, static pressure, diameter, fan speed, power input and temperature and elevation for each application. By doing this, they are able to bring you the best fan efficiency and performance range for your requirements. Our specialists also check inlet conditions, tip clearance, sound levels and fan diameter and build in safety factors for airflow and static pressure to handle less than ideal conditions. All these steps are taken to give you the best solution for your air-moving requirements.
Technical Support from Experienced Sales Engineers. • Evaluation of the application provides you with the best solution for your air moving requirements • System design advice
• Performance Optimizer Software • Auto CAD drawing system
Responsive Customer Service. • Short production lead time • Emergency production • Competitive pricing • No minimum order quantity • No production set-up charges • Reliable JIT and KanBan performance
Exceeding Your Expectations. • Committed to the quality standards of ISO 9001-2000 • New CNC machining centers • State of the art balancing machines (ISO grade G6.3 is our standard)
Sound Advice. Sound information is developed in the Multi-Wing laboratories for every model of every fan we make using standard testing and measuring procedures.
The information gathered is then entered into the Multi-Wing Performance Optimizer software package that helps select the best fan for a given application. Some of the more common fan noise problems are: • Air turbulence • High velocity air blowing over fixed components which are not part of the fan • Fan wheel unbalance • Resonance of fan or attached components • Rotating components rubbing on stationary parts • Operation in stall • Belt slippage • Air leakage which generates a whistle-type noise • Failing, misaligned or contaminated bearings on the fan or on the motor • Coupling misalignment • Motor noise, especially with improper power supply • Loose components
Helpful Fan Tips. Fan Laws—Speed Change
3. An impeller operating at 1750 RPM powered by 1.92 HP will operate at 1140 RPM powered by .53 HP.
1. Volume varies directly with fan speed.
.53 = 1.92 x (1140/1750)3
CFM2 = CFM1 x (RPM2/RPM1)
Useful Fan Formulas
2. Pressure varies with the square of the fan speed. Ps2 = Ps1 x (RPM2/RPM1)2 3. Horsepower varies with the cube of the fan speed. HP2 = HP1 x (RPM2/RPM1)3
Examples: 1. An impeller delivering a volume of 6932 CFM at 1750 RPM will deliver 4516 CFM at 1140 RPM. 4516 = 6932 x (1140/1750) 2. An impeller capable of delivering .25 inches WG static pressure at 1750 RPM will develop .11 inches WG static pressure at 1140 RPM.
Fan Tip Speed Dia. (inches) x π x RPM/720 = Feet Per Second Horsepower HP = Watts/745.7
Axial Thrust Fa = π x 5.193 x TP x D2 / 4 Fa = Net Axial Force in Lbs. TP = Fan Total Pressure D = Fan Diameter in Feet Total Pressure Static Pressure (SP) + Velocity Pressure (VP) Velocity V = CFM / Area (in Square Feet) Velocity Pressure VP = (V/4005)2 Total Efficiency TE = CFM x TP/BHP x 6356
Full Load Torque 63030 x BHP/RPM = Inch Lbs. of Torque
Thousands of Successful Worldwide Applications: • Air & Gas Compressors • Air Conditioners—Industrial & Commercial • Air-Cooled Heat Exchangers • Cooling Towers • Refrigeration—Industrial & Commercial • Ventilation • Air-Cooled Condensers • Locomotive Cooling • Railroad Air Conditioners • Refrigeration—Truck & Sea Containers • Generator Sets • Engine Cooling
Details Are Yours for the Asking. Because of all our attention to specific details, it’s easy to see why Multi-Wing Fans are successfully solving air-moving problems in over 25 countries around the world. They’re known and respected in a wide variety of market applications for high performance and trouble-free service. Contact us for further details on any of our quality air-moving solutions.
.11 = .25 x (1140/1750)2 P.O. Box 425 • 15030 Berkshire Industrial Parkway • Burton, Ohio 44021 • Toll Free: 800-311-8465 • Phone: 440-834-9400 • Fax: 440-834-0449 • Web Site: www.mw-america.com • E-Mail:
[email protected]
MULTI-WING AMERICA, INC.
A Crowley Company
ISO 9001-2000
FAN SELECTION: THE KEY TO COOLING PERFORMANCE. Selecting the right fan for your cooling application can improve system efficiency and result in quieter performance. You can gain these benefits by considering a few design variables that will help you optimize the fan blade selection process.
How Much Air Do You Need? Airflow is the first design consideration. Whether the application is a cooling tower or an air-cooled condenser, airflow is required to remove heat from the process. The amount of airflow required is determined by the rate of air velocity (measured in feet per minute) required through the condenser coils or cooling tower fill media in order to produce the desired latent heat transfer.
Static Pressure Static pressure in the simplest terms is a measure of the amount of resistance the fan must overcome to deliver X amount of air velocity across the coils or through a fill media. Static pressure (Ps) is measured in inches of water. The manufacturer through
testing has also determined the amount of static pressure for a coil or fill media.
Fan Diameter The fan diameter is a variable, but is normally determined by design constraints. Coil dimensions, availability of venturi orifices and package size limits all affect the size of the fan. However, the designer should always try to maximize the fan diameter for the application in order to provide maximum coil coverage and to reduce system static pressure.
Operating Speed and Available Power Like the fan diameter, speed and power are determined by design constraints, or influenced by industry tradition. The fan application engineer will need to know the designers desired operating speed and available horsepower in order to meet the designer's expectations.
Ambient Operating Temperature and Elevation Ambient operating temperature and elevation are two parameters that the
fan engineer will need to be aware of in order to make the best recommendation for the cooling application. Typically, coil and fan test data are converted to what is called standard air conditions (70˚ F @ sea level). This gives a common starting point for calculating performance variance from "standard condition."
As you can see, the fan's ability to generate pressure is reduced by the lower air density caused by the increased temperature and elevation. The example illustrates conditions that an air-cooled condenser application might be exposed to on a hot summer day in Denver, Colorado.
For example, a fan has the following performance capabilities at "standard conditions." Table 1 provides a comparison of fan operation in standard vs. actual conditions.
With the knowledge of temperature and elevation, the fan application engineer can eliminate fans that would perform well at standard conditions but would become marginal selections at the actual operating conditions.
Table 1. Effects of Operating Conditions on Fan Performance
Actual Operating Environment
Standard Conditions: 70˚ @ sea level 10,000 cfm at .50 inWG Ps requiring 1.5 HP Actual Conditions: 120˚ @ 5,000 ft. 10,000 cfm at .38 inWG Ps requiring 1.14 HP
While the operating environment will have little effect on the airflow performance, it has great effect on the life of the fan. For example, coastal cooler applications are exposed to salt spray, and chemical process coolers are exposed to chemical corrosives. With knowledge of the operating environment, the fan engineer can make the material or coating recommendation that will provide the best solution to the operating
environment. Table 2 shows available blade materials and their suitable operating environments.
Optimum Inlet Geometry and Fan Tip Clearance The fan inlet geometry and tip clearance also affect fan performance. Most fan blade manufacturers test their products to provide the maximum performance and efficiency. This performance is achieved using aerodynamically superior bell mouth inlets and tight fan tip clearances. The fan application engineer will need to know the application inlet conditions so that safety margins, if required, can be added to the design parameters in order to compensate for the difference between actual and test conditions (Figure 1).
Multi-Wing Specifications Performance Factors Variable Factors Application Assistance Multi-Wing Home
Figure 1. Building safety factors into design parameters avoids system underperformance.
NEXT
P.O. Box 425 • 15030 Berkshire Industrial Parkway • Burton, Ohio 44021 • Toll Free: 800-311-8465 • Phone: 440-834-9400 • Fax: 440-834-0449 • Web Site: www.mw-america.com • E-Mail:
[email protected]
MULTI-WING AMERICA, INC.
A Crowley Company
ISO 9001-2000
FAN SELECTION: Continued Figure 1. Testing Helps Predict Performance
Figure 1. Building safety factors into design parameters avoids system underperformance.
Minimizing Fan Noise Noise is always a concern when it comes to applications in which air movement is required. With all the
concern about noise, the question becomes, how do you minimize it?
possible diameter will reduce air velocity across the fan blade.
The best way to minimize fan noise is to produce the most aerodynamically efficient operating conditions as is possible.
To reduce tip-speed-generated noise, the fan should also operate at the lowest speed at which application parameters can be met.
This is achieved by selecting a fan blade that will operate within its maximum operating efficiency range. An aerodynamically efficient airfoil design like the Multi-Wing Z profile, creates less turbulence as energy is transferred to the air.
The Fan Blade Selection Process
The fan blade diameter should also be the largest possible for the physical limits of the application. The maximum
Armed with the information provided by the customer, the fan application engineer, with the help of sophisticated computer software, reviews all possible combinations in order to provide a selection which produces the maximum performance range (Figure 2).
Figure 2. An Ideal Solution? When working with an application engineer, make sure you utilize a selection method based on providing an efficient working performance range that builds in safety factors for both airflow and static pressure when conditions are less than ideal. Using the selection technique, system inefficiencies, both known and unknown, that will affect fan performance are compensated for, reducing the potential for an under-performing recommendation.
Figure 2. Although this may appear to be the perfect solution, it will only work if all operating conditions in your application are ideal.
H Series Z Series W Series 8 Type
Table 2. Suitable Blade Materials for a Variety of Applications. Blade Material
Symbol
Temperature Range
Application*
Fiberglass-Reinforced Polypropylene Fiberglass-Reinforced Nylon “Super Tuff” Nylon Fiberglass-Reinforced Nylon-Electro Anti-Static Die Cast Aluminum
PPG PAG PAGST PAGAS AL
-40˚ F to +185˚ F -50˚ F to +250˚ F -50˚ F to +250˚ F -40˚ F to +250˚ F -60˚ F to +300˚ F
Corrosive: salt spray; light acid Corrosive: acid; light salt Extreme Vibration Explosive proof Wide temperature variations
Multi-Wing Specifications Performance Factors Variable Factors Application Assistance Multi-Wing Home
* Always consult manufacturer to assure material performance.
P.O. Box 425 • 15030 Berkshire Industrial Parkway • Burton, Ohio 44021 • Toll Free: 800-311-8465 • Phone: 440-834-9400 • Fax: 440-834-0449 • Web Site: www.mw-america.com • E-Mail:
[email protected]
