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Performance Specifications

Jan. 2000 PROPRIETARY information of ROBINSON INDUSTRIES, INC. Do NOT copy or distribute.

1

Performance Specifications

Jan. 2000 PROPRIETARY information of ROBINSON INDUSTRIES, INC. Do NOT copy or distribute.

2

Performance Specifications

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Performance Specifications Effect of Fan Location in System (F.D. Fans vs. I.D. Fans) Given: Airflow = 30,000 SCFM (@70° F and density = 0.075 lb/ft^3) Air temperature from process = 200° F Discharge temperature from RTO = 400° F FD fan pressure required = 20 in-H2O #1. Forced Draft Fan: Specify fan performance of 37,500 ACFM, 20 in-H2O (-1 in-H2O @ Inlet), 200° F, 0.060 lb/ft^3

Stack

RTO Process

200°F

200°F

Heat 400°F

+19 in-H2O

1

Q P(gage) Density 1. 37500 -1 0.060 2. 35714 +19 0.063 3. 46875 +14.5 0.048 4. 48913 +0 0.046 5. 48913 +0 0.046 HP(req’d) = [(37500)(20)] / [(6362)(0.75)] = 157 HP

R

FD Fan -1 in-H2O

400°F

0 in-H2O

2

3

Fan ∆P = 20 in-H2O

4

5

RTO ∆P = 14.5 in-H2O

T(°F) 200 200 400 400 400

#2. Induced Draft Fan: Specify fan performance of 50,562 ACFM, 14.8 in-H2O (-14.8 in-H2O @ Inlet), 400° F, 0.0445 lb/ft^3 Stack

RTO Process

200°F

200°F

Heat 400°F

R -1 in-H2O 1

ID Fan 0 in-H2O

-1 in-H2O 2

400°F

400°F

3

5

4 RTO ∆P = 14.0 in-H2O

Fan ∆P = 14.8 in-H2O

Q P(gage) Density T(°F) 1. 37500 -1 0.060 200 2. 37500 -1 0.060 200 3. 48913 -0.8 0.046 400 4. 50562 -14.8 0.0445 400 5. 48913 0 0.046 400 HP(req’d) = [(50562)(14.8)] / [(6362)(0.75)] = 157 HP NOTE: A higher-volume, lowerpressure fan is required.

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Performance Specifications Fan Inquiry Form Rep. Office ________________________________________

By ______________________

Date ____________________

Customer _________________________________________ Date Quotation Req.___________________________________ Street ________________________________________ City __________________________________________ State ____________________ ZIP _____________________ Telephone _____________________________________ Fax ________________________________________________ Attention ______________________________________ Reference or Project ________________________________ Number of Fans Required ____________________________ Description of Service ______________________________________________________________________________________ ____________________________________________________________________________________________________ ____________________________________________________________________________________________________ Max. Mechanical Design Temp ________ (Deg. F) ■ Clean Air

■ Dust/Moisture-Laden

■ Abrasive

Materials of Construction: Wheel_______________________ Type of Dust or Gas ________________________________. Altitude _______________________________Ft. Above S.L. Fan Performance Requirements CONDITION

INLET VOLUME ACFM OR SCFM

■ Severe Abrasive

■ Corrosive

Casing______________________________________________ _______________________________________________#/HR Ambient Temp. Range _________to _________F

FAN SP, IN. WG

INLET SP, IN. WG

INLET TEMP., DEGREES F.

INLET DENSITY LB/FT3

Attach gas composition and/or molecular weight if available. ■ Radial Blade ■ Radial Tip ■ Other ■ BC ■ AF ■ FC ■ Optional Specify ________________________________________________________________________________

Fan Type:

Arrangement No. ___________________________________ Rotation __________________________________________ Inlets: Inlet Boxes: Drive: Motor By:

■ ■ ■ ■

Singles ■ Yes ■ Direct Coupled ■ RI ■

Double No V-Belt Drive Others

■ Optional ■ Optional ■ VFD

Optional__________________________________________ Discharge ________________________________________ Desired Noise Limit ________

dBA @_______________Ft.

■ Other __________________________________________

Maximum Motor HP_____________________Preferred Speed __________Type _________Volts _______Phase ____________ Cycle _____________________________ Accessories Yes (Y), No (N) or Optional (O) ■ Access Door ■ Roller/Ball Bearings Special Requirements ■ Drain ■ Casing ■ Inlet Box ■ Sleeveoil Bearings ■ Air Perf. Test ■ Inlet Screen ■ Split Housing ■ Mech. Run Test ■ Flanged Inlet ■ Blade Wear Protection ■ Overspeed Test ■ Flanged Outlet ■ Scroll Liners ■ Sound Test ■ Drive Guard ■ Side Liners ■ Certified Matl. Test Reports ■ Heat Flinger ■ Silencer ■ Certified Welding ■ Shaft Seal Type __________ ■ Circulating Oil System ■ API 673 ■ Insulation Clips ■ Turning Gear ■ Special Coatings ■ Insulated Housing ■ Spray Nozzles Wheel ___________________ ■ Radial Inlet Damper ■ Special Paint, Coating Casing___________________ ■ Louvered Inlet Damper ■ Spring Isolation Base ■ Spark Resistant ■ Outlet Damper ■ Bearing Temp. Detectors AMCA-A, B or C _____ ■ Independent Bearing Pedestals ■ Bearing Vibration Detectors ■ Pressure Test ■ Pedestal Sole Plates ■ Separate Damper, Size ______________________________________________________________________________ Special Requirements, Comments or Sketch: Attach Separate Sheet

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Application Information

Paddlewheel

Backward Inclined

• • • •

Open design/no shroud 60-65% static efficiency Inexpensive design Good for high temperature or highly erosive applications • Medium to high pressure

• Static efficiency to 80% • Low to medium tip speed capabilities

Radial Blade

Backward Curved

• Static efficiency to 75% • High tip speed capabilities • Reasonable running clearance • Best for erosive or sticky particulate

• Medium to high tip speed capabilities • High efficiency to 83% • Clean or dirty airstreams • Solid one-piece blade design

Radial Tip

Airfoil

• Static efficiency to 75% • Medium to high tip speed capabilities • Running clearance tighter than radial blade but not as critical as backward inclined and airfoil • Good for high particulate airstream

• Static efficiency to 87% • Medium to high tip speed capabilities • Relatively tight running clearances

Forward Curved (Sirrocco)

Axial Flow

• Smallest diameter wheel for a given pressure requirement • High volume capability • 55-65% static efficiency • Often used for high temperatures

• High volume, low pressure • 35-50% static efficiency • High temperature furnace recirc. applications • Reversing flow capability • Airflow parallel to shaft axis

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Application Information

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Selection Information Development of Fan Performance Curve Reprinted from Publication 210 with the express written permission of the Air Movement and Control Association, Inc., 30 W. University Drive, Arlington Heights, IL 60004-1893.

Typical Outlet Duct Test Setup Notes 1. Dotted lines on fan inlet indicate an inlet bell and one equivalent duct diameter which may be used for inlet duct simulation. The duct friction shall not be considered. 2. Dotted lines on the outlet indicate a diffuser cone which may be used to approach more nearly free delivery.

Test duct orifice plates from shut-off to wide open for points A, B, C etc.

B C A D

E

SP D

BHP

F

E

SP

C B

F

A

CFM Jan. 2000 PROPRIETARY information of ROBINSON INDUSTRIES, INC. Do NOT copy or distribute.

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Selection Information

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Selection Information

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Selection Information

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Selection Information

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Selection Information

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Selection Information

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Selection Information

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Selection Information

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Selection Information Single Point Operation

STATIC PRESSURE-INCHES H2O

The actual operating point will be determined by the intersection of the system resistance curve and the fan performance curve. The fan must be selected correctly to exactly meet the design requirement.

SP

50

System resistance curve SP = 40"

40

Fan performance curve

30 20 10

BHP = CFM x SP 6362 x Es

STATIC EFFICIENCY, %

BHP

2000

(neglecting compressibility)

BHP

1000

BHP = 1257

Fan Selection Considerations • Efficiency • Stability • Sound • Size • Speed

Es = 0.75 (75%)

80 Es

40

50

100 150 200 THOUSANDS CFM

250

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Selection Information

ACFM = actual cubic feet per minute SP = static pressure Kp = compressibility factor 6362 = conversion constant Static efficiency = Fan HP =

ACFM x SP x Kp , 6362 x Fan HP

or

ACFM x SP x Kp 6362 x static efficiency

Px xS M F 62 63 AC

Kp

HP )= Air tput (ou

Fan HP (input)

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Selection Information

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Selection Information

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Selection Information Regulation by Radial Inlet Damper or Inlet Box Damper (Parallel Damper) Inlet damper control offers several advantages compared to outlet dampering. Because the air is prespun in the same angular direction as the fanwheel rotation, the energy required to operate the fan is significantly reduced. Also, the multiple vanes just upstream of the fanwheel inlet provide a controlled presentation of air to the fanwheel that provides smooth control over a wide range of operation. With this system, there is, in fact, a new fan performance curve for every damper position. See the example below:

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Selection Information

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Selection Information

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Selection Information The Size Change Fan Laws make it easy to determine the performance for a larger size fan based on the known performance of an existing fan or a laboratory model fan. This requires that the fans be geometrically similar. Note however that Robinson has developed modified versions of this fan law that allow accurate prediction of tipped-out (slightly larger diameter) and de-tipped (slightly smaller diameter) fan rotors. This is sometimes a very cost-effective means of accomplishing in-field modifications to increase performance or decrease horsepower consumption.

Size Change Fan Law CFM2 = (Size2 / Size1)3 (CFM1)

Volume:

Static Pressure: SP2 = (Size2 / Size1)2 (SP1) Horsepower:

BHP2 = (Size2 / Size1)5 (BHP1)

Sound Power:

LW2 = LW1 + 70 log (Size2 / Size1)

Example: (Fans with geometric similarity) 100" diameter wheel x 10" tip width 100,000 CFM @ 20" SP @ 70° F @ 393 BHP What is performance at 90-1/2" diameter wheel x 9.05" tip width? CFM2 = (90.5/100)3 (100,000) = 74,122 CFM SP2 = (90.5/100)2 (20) = 16.3 in. H2O BHP2 = (90.5/100)5 (393) = 239 HP Example: (Fans to be tipped out or de-tipped) CFMMod = (Dia2/Dia1)2 (CFMorig) SPMod

= (Dia2/Dia1)2 (SPorig)

BHPMod = (Dia2/Dia1)4 (BHPorig) Example:

100" diameter wheel x 10" tip width 100,000 CFM @ 20" SP @ 70° F @ 393 BHP

What is performance with a 5% tipout to 105'' diameter? CFMMod = (105/100)2 (100,000) = 110,250 CFM SPMod = (105/100)2 (20) = 22.05 in. H2O BHPMod = (105/100)4 (393) = 478 HP Note: Effect on sound pressure is greater due to decreased cut-off clearance.

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Selection Information

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Selection Information

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Selection Information

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Selection Information

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Selection Information

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Selection Information

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Selection Information

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Selection Information

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Selection Information

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Selection Information

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Selection Information

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Selection Information

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Selection Information

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Selection Information

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Selection Information Erosion Erosion is a major problem on some induced draft fans. High dust loading combined with high inlet velocities can result in dangerous shutdowns. Hard surface wear liners can help. But reducing the fan inlet velocity by specifying a lower speed, larger diameter fan can result in reduced wear and extended fan wheel life. The kinetic energy (KE) of the particles decreases with the square of the velocity. Erosion can also be reduced by reducing the particulate flow rate (lbs./hour) or by reducing the average particle size. 1. Reducing the particulate flow rate (lbs./hour). 2. Reducing the average particle size. 3. Reducing the particle velocity and the gas velocity at the fan inlet. Note that changing from a single inlet fan design to a double inlet design is a very effective means of decreasing the fan inlet velocity.

Note: The presence of particulate matter in the gas stream affects the average density at the fan inlet and therefore the motor power requirement as is shown on page 1. Jan. 2000 PROPRIETARY information of ROBINSON INDUSTRIES, INC. Do NOT copy or distribute.

39

Selection Information

(Note: Over 180 different materials tested to date)

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Mechanical Design

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Mechanical Design

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Mechanical Design

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Mechanical Design

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Mechanical Design

Comparative Advantages of Oil and Grease Advantages of Grease 1. Maintenance work is ordinarily reduced since there are no oil levels to maintain. 2. Grease in proper quantity is more easily confined to the housing. Design of enclosures can therefore be simplified. 3. Freedom from leakage is readily accomplished in food, textile, chemical industries and where contamination of products must be avoided. 4. Grease improves the efficiency of labyrinth enclosures and offers a better protection for the bearing. 5. Bearing can be installed in a high velocity gas stream.

Advantages of Oil 1. Oil is easier to drain and refill. This may be more desirable for applications requiring short lubricating intervals. 2. The correct amount of lubricant is more easily controlled. 3. Oil lends itself more readily to the lubrication of all parts of a machine. 4. Oil lends itself to applications with higher temperatures. 5. The bearing friction and temperature rise are usually more favorable.

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Mechanical Design

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Mechanical Design

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Mechanical Design

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Mechanical Design

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Mechanical Design Sleeve-Type Bearings • • • • • • • •

No moving parts No metal-to-metal contact/infinite fatigue life Babbitted surfaces Split design for easy maintenance Shaft-mounted thrust collar (fixed bearings) Infinite axial expansion capability (for shaft) External cooling (water, air, circulating oil) Auxiliary dust seals available

Note: These bearings are generally used for large diameter fans. They have higher load and speed capabilities than rolling element bearings.

Fan Bearing Comparison Item of Comparison

Standard Ball Bearing (Deep Groove)

Spherical Roller Bearing (SAF Housing)

Calculated Life Radial Load Capability Axial Load Capability Cooling Capability water cooling air cooling 5. Circulating Oil max. flow rate 6. Static Oil Lube

40,000 / 80,000hrs. Low Low Limited No No No N/A No

80,000 hrs. Medium Medium Limited No No Yes Limited Yes (5-7/16" brg. = .6 liters)

ring oiled Grease Lubrication Thermal Analysis Dynamic Stiffness Dynamic Damping Shaft Tolerances

No Yes Yes Medium Minimal Nominal +0.000 / -0.0005 32 None

No Yes Yes High Minimal Nominal +0.000 / -0.005 32 None

Yes 3/16" – 3/8" No No Easy

Yes (brg.) Std = 3/8" Yes No Easy

Infinite Very Large Very Large Very High Yes Yes Yes Very High Yes (5-7/16" brg. XC = 2.95 L / RT = 4.49 L) Yes No Yes Medium (oil film) Good Nominal +0.000 / -0.002 32 XC – None RT – groove/collar Yes (liner to housing) Unlimited Yes Yes Easy

Difficult (Must remove coupling and move motor before removing/installing bearing) Worldwide Stock Shortest

Difficult (Must remove coupling and move motor before removing/installing bearing) Worldwide Stock Medium

Fairly Easy (Loosen coupling, jack up shaft about 1/4", slide old bearing out) USA only Stock Longest

Low

Low

High

1. 2. 3. 4.

7. 8. 9. 10. 11.

12. Shaft Surface 13. Shaft Specialties 14. 15. 16. 17. 18.

Self-Aligning Axial Expansion Split Housing Split Bearing Field Replacement (Outboard) 19. Field Replacement (Inboard) 20. Spare Parts 21. Availability 22. Axial Length (affects shaft sizing) 23. Price

Dodge Sleeve Bearing

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Mechanical Design

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Mechanical Design

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Mechanical Design

3

y = WL 48EI

D = shaft dia. (in.) I = πD4 (in.4) 64 E = Shaft modulus of elasticity (lbs./in.2) W = fanwheel weight (lbs.) A, B, L = distance (in.) y = shaft deflection (in.) Ncr = critical speed (rpm)

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Mechanical Design

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Mechanical Design

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Mechanical Design Fanwheel Design Fatigue Life ASME fatigue life curves are used for both high-cycle and low-cycle fatigue calculations. The following is an example for ASTM A514 material.

Stress (psi)

107

106

105

104 10

102

103

104

105

106

Impact Toughness

Absorbed Energy ft.-lbs.

Crack propagation rate is a function of the toughness of the material. This can be quantified by Charpy V-Notch testing. Materials with low impact toughness are more glasslike or brittle. The impact toughness varies as a function of temperature for many materials. There is a history of rapid, unexpected failures of fan rotors during cold weather start-up or operation that has been related to low material impact toughness. Therefore, Robinson recommends using materials that have an adequate impact toughness at the lowest expected operating temperature. The graph below shows that thermal stress relief of welded A514 material has a detrimental effect on the impact toughness. Therefore, thermal stress relief of A514 fanwheels is not a recommended practice. Other materials, of course, may not react to thermal stress relief in this way.

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Mechanical Design

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Mechanical Design

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Mechanical Design

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Mechanical Design

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Mechanical Design

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Mechanical Design

Shaft Seals: These are designed to minimize leakage of dangerous gases from the process, or to exclude atmospheric air from the process itself. Several seal designs are available with varying sealing effectiveness. (See section on shaft seal details).

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Mechanical Design

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Mechanical Design

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Mechanical Design

Shaft may be chromeplated or ceramic-coated under packing area.

Shaft may be chromeplated or ceramic-coated under packing area.

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Mechanical Design

Shaft may be chromeplated or ceramic-coated under carbon.

Shaft may be chromeplated or ceramic-coated under carbon.

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Mechanical Design

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Mechanical Design

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Mechanical Design

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Mechanical Design

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Mechanical Design

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Mechanical Design

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Mechanical Design

For a ducted inlet/ducted outlet fan in a free field:

(

Lpd

Lpe

Lpf

Lpm

LpTOTAL = 10 log 1010 + 10 10 + 1010 + 1010

)

For example:

(

83

88

81

85

LpTOTAL = 10 log 10 10 + 10 10 + 10 10 + 10 10

)

LpTOTAL = 91.04dB In addition to the sound level, the duration of exposure to a particular noise level is also an important local noise concern. The table below outlines OSHA’s permissible noise exposure limits.

Duration per day, hours

Sound level dBA

8 ..................................................................90 6 ..................................................................92 4 ..................................................................95 3 ..................................................................97 2 ................................................................100 1-1/2 ..........................................................102 1 ................................................................105 1/2 ..............................................................110 1/4 or less ..................................................115 When the daily noise exposure is composed of two or more periods of noise amounts of different levels, their combined affect should be considered, rather than the individual effect of each. If the sum of the following fractions — C1/T1 + C2/T2… Cn/Tn — exceeds unity, then the mixed exposure should be considered to exceed the limit value. Cn indicates the total time of exposure at a specified noise level, and Tn indicates the total time of exposure permitted at that level. Federal Register, Vol. 34, No. 96, May 20, 1959, pp. 7849.

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Mechanical Design

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Mechanical Design

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Mechanical Design

time (seconds) delta RPM = change in speed (rev./min.) available torque = (motor torque capability) - (fan torque requirement) at all speeds from zero to normal operating speed (ft.-lb.) WR2 = fan rotor rotational moment of inertia (lb.-ft.2)

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Mechanical Design

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Mechanical Design

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Mechanical Design

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Fabrication & Quality Control

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Fabrication & Quality Control

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Fabrication & Quality Control

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Fabrication & Quality Control

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Fabrication & Quality Control

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Fabrication & Quality Control

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Fabrication & Quality Control

Notes: 1. The numerical value after the letter G is equal to the product of ePER(2πf) expressed in millimeters per second. G = ePER (2πf), or ePER =

Example: Rotor weight, (m) = 1000 lbs; Rotor Dia = 75 inch; Maximum operating frequency = 1200 rpm ÷ 60 s/min = 20 cyc/s; Balance to grade G2.5 = 2.5mm/sec. G G ePER = = 2π (20) = 0.02 mm 2πf 0.02 mm ÷ 25.4 mm/in = .0008 in

UPER

UPER = ePER x m = (0.0008 in)(1000 lb) = 0.8 lb-in

G (2πf) = max residual unbalance for a particular rotor.

UPER = ePER x m = Gm 2πf

0.8 lb in x 16 oz/lb = 12.8 oz-in Shaft* vibration in free space = 2.5mm/sec in = 0.10 sec (peak velocity) 25.4mm/in

(

)

*Note: Bearing vibration will be considerably lower than shaft vibration. Jan. 2000 PROPRIETARY information of ROBINSON INDUSTRIES, INC. Do NOT copy or distribute.

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Fabrication & Quality Control

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Fabrication & Quality Control

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Fabrication & Quality Control Pressure Test Procedure for Fan Casings (When no leakage rate is included in the specifications) 1. Blind flange with rubber gasket over all inlet and outlet openings. 2. Fans with a peak operating static pressure from 0 in-H2O to 138 in-H2O to be pressure tested with compressed air. Fans with peak operating static pressures over 138 in-H2O to be pressure tested with water. 3. Attach plant air line or water line to casing drain or other entry point as follows:

Safety Relief

Plant Air/ H2 O

Plant Air/ H2O

Safety Relief

4. Use U-tube water gauge or a 0-5 psi pressure gauge for pressure of 0 to 50 in-H2O. Use 0-5 psi pressure gauge for pressures above 50 in-H2O. 5. Pressurize casing to highest operating static pressure of the fan. (Examine all operating conditions, including 70° F, and use the highest pressure.) 6. Close inlet valve. 7. All welds are to be bubble tested with leak detection solution. Repair all weld leaks and begin retesting. 8. On the Pressure Test Log Sheet (See page 90), record pressure once every 60 seconds for 15 minutes. 9. If average leak rate is less than 2.0 in-H2O per minute, then the unit is satisfactory. If the average leak rate exceeds 2.0 in-H2O per minute, inspect the area of the shaft seal, inlet/outlet flanges and casing split gaskets first for major leaks. 10. Continue to repair leaks and rerun pressure test until the required leak rate is achieved.

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89

Fabrication & Quality Control Pressure Test Log Sheet Factory Order #

Serial #

Test Date

Size and Description Assembly Drawing # Shaft Seal Material

Gasket Material

Highest Operating Static Pressure of Fan (all operating conditions, including 70° F)

in.-H2O

Test Pressure (max.)

in.-H2O

Casing Welded:

Inside ■

Outside ■

Both Sides ■

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90

Fabrication & Quality Control

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91

Fabrication & Quality Control

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92

Installation Information

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93

Installation Information

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94

Installation Information

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95

Troubleshooting

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96

Troubleshooting

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97

Troubleshooting

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98

Troubleshooting

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99

Troubleshooting

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Troubleshooting

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Engineering Publications Engineering Publications 1. Gutzwiller, H.L., Robinson Industries, Inc. “Balance and Vibration Considerations for Fans,” AMCA Technical Seminar, Los Angeles, California, November 1-3, 1995. Abstract: For years, we have reviewed specifications from users of industrial fans that show a misunderstanding between the terms “balance” and “vibration.” While the two terms are related, they have independent definitions; and it is important for both users and manufacturers to clearly understand the differences. The Air Moving and Control Association (AMCA) has formed a committee to draft a standard #204 entitled “Balance Quality and Vibration Levels for Fans.” Other standards exist for defining balance and vibration requirements for the general rotating equipment. However, this committee is to address the special consideration for fan equipment in particular. The purpose of the standard is to “define appropriate fan balance quality and operating vibration levels to those who specify, manufacture, use and maintain fan equipment.” 2. Banyay, H.D., Robinson Industries, Inc. “Maximizing Fan Reliability in Kilns, Dryers and Burners,” Ceramic Industry, Vol. 146, No. 4, April 1996, pages 5-15. Abstract: The purpose of this paper is to discuss the proper application of bearings on hot gas fans. The gas temperature for these can range up to 1300° F or more. The fans typically are V-belt driven (AMCA arrangement #1 or #9) and range up to 100 HP. 3. Gutzwiller, H.L., and Banyay, H.D., Robinson Industries, Inc., and Ball, W.D., John Zink Company. “Marine Vapour Recovery System Blowers,” Fans for Hazardous Applications, Seminar by the Fluid Machinery Committee of the Institution of the Mechanical Engineers, London, England, October 4, 1994. Abstract: This paper describes the design and application of high-pressure blowers used to exhaust combustible hydrocarbon vapors from seagoing tankers. Important considerations include stable operation over a wide flow range, spark-resistant and gas-tight construction, minimal noise, resistance to salt-spray corrosion, and ease of maintenance.

4. Grupp, David, Robinson Industries, Inc. “Natural Frequency of a High Temperature Plug Unit and Wall in a Furnace Application,” Engineering Paper 2566-94-A1, AMCA Engineering Conference, St. Petersburg Beach, Florida, February 20-22, 1994. Abstract: Critical speed is a well-known design parameter in the fan industry. Most commonly, critical speed is related only to the fan rotor and shaft assembly. Often the effects of the bearings, support structure, foundation and soil are neglected as properties of the system. In most cases, the stiffness of each of these properties is so high that their effect is indeed negligible. However, when the effects of these properties become significant, the fan engineer must be careful to design for the system critical speed. The following paper will present a fan application problem in which the stiffness of a wall in a furnace structure resulted in a unique system critical resonance at the operating speed of five high temperature axial flow fan assemblies. 5. Gutzwiller, H.L., and Banyay, H.D., Robinson Industries, Inc., and Cohen, S.N., Fuller Company. “Cement Plant Preheater Fan Buildup Control,” IEEE Conference, Tarpon Springs, Florida, May 22, 1990. Abstract: In recent years, greater demands with regard to throughput and efficient utilization of heat in the kiln due to process design changes have placed greater demands on the kilninduced draft fan. These fans have been designed with ever-increasing volume and static pressure requirements, as well as higher process gas temperatures. This, of course, means larger fan rotors operating at very high tip speeds. Along with these design changes, the problem of build-up on the impeller has also increased markedly … But why must some plants battle this problem routinely while others have no significant ID fan build-up at all? What causes kiln ID fan build-up problems? How can it be stopped?

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