BELT CONVEYOR DESIGN Date: 9/19/14 8:02 AM
Knowns: Belt Weight #/ft Length of conveyor ft Coeff. of friction Belt speed fpm Total Material wt.# Incline angle (deg) Drive wrap angle (deg) Tail wrap angle (deg)
Carrying belt wt. Total "topside" weight
6.7 13.25 0.3 210 1,469 5 180 180
88.8 lbs 1,557.5 lbs
Belt Width (BW) Pulley Face Width (F) Bearing Centers (BC) B.C.M.F. P.I.W. Drive Pulley (#/in) P.I.W. Tail Pulley (#/in) Drive pulley diam. (in) Tail Pulley diam. (in) (see Dodge book, table 1, pg.PT 13-12
18 20 24 4 118 52 24 24
Drive Pulley Resultant Load (R) (lbf) Tail Pulley Resultant Load (R) (lbf) (see Dodge book table 3, pg.PT 13-13 for shaft sizes)
in in in (Bearing Center Minus Face) (Pulley Pounds per Inch of Belt Width) (Pulley Pounds per Inch of Belt Width) 24" Drive Pulley Diameter 24" Tail Pulley Diameter
3,064 (use 1/2 this to check bearing 1,886 load rating @ shaft rpm)
Horse Power Calcs: Horizontal hp Vertical hp
Total HP Service Factor Design HP Selected Drive hp Motor Selection: 7 HP, 213T Frame, 1750 RPM
3.0 HP 0.9 HP
3.83 HP 1.4 5.36 HP 7.5
Tension Calcs: Te (Effective Belt Tension) 1,178.6 lbs Cw (Drive Factor) 0.8 See Dodge book, table 7, pg.PT 13-52) T2 (slack side ten.) 942.9 lbs T1 (tight side ten.) 2,121.4 lbs
Kb = 1.5 or 2.5 if overhug load Dodge Table 4 N value (BCMF / 2) Dodge Table 4 addition to N value Dodge Table 4, A value (Dodge pg. PT-13-15)
2.5 2 1.75 3.75
Allowable Torsional Shearing Stress (S) Drive Pulley Shaft (formula from Dodge, Step 7, pg PT13-15)
8,000 8,000psi for 1045 or 10,000psi for 4140, keyed shaft) 2 5/16 2 11/16 Selected Drive Pulley Shaft Dia 1 15/16 Selected Tail Pulley Shaft
Motor RPM Calculated Gearbox ratio Ave. Mechanical Efficiency of Gearbox (from Rex) Selected Gearbox ratio Gearbox spkt rpm Gearbox Output Torque Equivalent Gearbox Output Torque (from Rex)
1750 52.36 95% 31.63 55.33 8,116 11,363
req'd chain ratio Req'd final rpm Gearbox (normally small) spkt teeth Large spkt teeth (calculated = 36)
1.6554 :1 33.42 22 Sprocket: Martin 100E22H 35 Sprocket: Martin 100E35
Actual final RPM Actual final Torque FPM Low Speed Shaft Gearbox Over Hung Load (from Rex, pg. H-9) Gear Box spkt. P.D. Load Connection Factor FC (from pg. H-9) Load Connection Factor LF (from table 7, p. H-20) O.L. = (126,000 * HP * FC * LF) / (P.D. * RPM) Gearbox Load Rating (from table 8, pg. H-21) RC100 Chain (from Dodge, pg. PT12-30 to 39) Small Sprocket No. of Teeth (from above) Gear Box spkt. P.D. RPM (from table) Rated Hp (from table) Required RPM (from above) Interpolated HP rating Reducer Output Chain FPM = Chain Pull (Drive Spkt.)
:1 Actual gearbox selected: Rexnord MARS 11 - Nom. Ratio 31.63:1 RPM in/lbs (Nominal) in/lbs (Max)
34.78 13,592 in/lbs 218.51
OK 6.407 1 1.3 3,466 3,860
in (assumed 4 1/2" in) lbs lbs
OK 22 6.407 in 50 7.3 55 8.08 92.8 2,667 lbs.
Shaft: (1045) Allowable torsional shearing stress (Ss) Shock & Fatigue factor forTorsional Moment Kt Shock & Fatigue factor for Bending Moment Km B (1 for solid shafts) Allowable bending stress (S) See Machinery Handbook pgs. 310-311
8,000 psi 1 1.5 1 16,000 psi
Drive Pulley Overhung Load: Edge of hub to c/l brg. Bending moment (Mb) @ Drive Spkt. Drive shaft tortional moment (Mt) Min. Calculated Drive Shaft Diameter
File: 244784946.xls.ms_office
4.5 13,789 13,592 2 8/16
inches in-lbs in-lbs inches
Check for slow drives see Dodge p. PT12-29
Belting Formulas http://www.niba.org/beltingformulas.html CONVEYOR BELT TENSION CALCULATION Calculation F1 = .035" (Normal friction factor for average conditions (over 20 degree F) to move empty belt). s TC = F1 X L L = Belt length (feet). X CW CW = Weight of conveyor belt components (See Table A in Engineering Handbook).
TL= F2 X L X MW
F2s = .04" (Normal friction factor to move load horizontally). L = Belt length (feet). MW = Material weight (lbs. per lineal foot) MW =
33.3 TPH / Belt Speed (fpm)
or
MW =
Total Material load in lbs. / L
H = Difference between elevation of terminal pulleys (ft.) TH= H X MW TE = TC + TL + TH Second, additional tension must be added to the effective Belt Tension (Te) to prevent slippage on the drive pulley. This is called Slack Side Tension (Ts), or commonly called T2.
Ts = D X Te D = Drive factor (See Table B in Engineering Handbook). Next, the total tension To = Te + Ts To is the total operating tension, or commonly called Allowable Working Tension , and is expressed in PIW (pounds per inch of width). To is sometimes referred to as TL.
