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Conveyor Chain Selection Ta b l e 9 : S p e e d C o r r e c t i o n F a c t o r ( S C ) Number Sprocket Teeth 6 7 8 9 10 11 12 15 16 18 20 24 10 25 50 Chain Speed (ft / min) 75 100 125 150 175 200 225 250 275 300 400 500 .92 .86 .81 .79 .78 .76 .74 .73 .73 .72 .72 .71 1.37 1.13 1.04 .98 .94 .90 .86 .83 .81 .80 .79 .77 1.68 1.27 1.16 1.07 1.02 .97 .93 .89 .86 .83 .83 .80 1.09 .97 .91 .87 .84 .82 .79 .77 .76 .75 .75 .74 2.00 1.44 1.26 1.17 1.09 1.03 .99 .94 .89 .88 .86 .82 2.40 1.61 1.37 1.26 1.16 1.09 1.05 .98 .94 .91 .89 .85 Ta b l e 1 0 : S e r v i c e F a c t o r s Frequency Type Operating Shock Conveyor Conditions Loading Loading SF3 SF1 SF2 Infrequent 1.0 Frequent 1.2 Uniform 1.0 Moderate Shock Load 1.2 Heavy Shock Loading 1.5 Clean Environment 1.0 Moderate Environment 1.2 Severe Environment 1.4 2.91 1.81 1.49 1.36 1.24 1.15 1.10 1.02 .97 .94 .92 .88 3.57 2.04 1.63 1.45 1.31 1.22 1.16 1.07 1.01 .98 .95 .90 4.41 2.29 1.76 1.55 1.37 1.28 1.21 1.11 1.05 1.01 .98 .94 5.65 2.60 1.93 1.65 1.45 1.34 1.26 1.25 1.08 1.04 1.01 .96 7.35 2.96 2.10 1.76 1.53 1.40 1.32 1.19 1.12 1.08 1.04 .98 3.42 2.29 1.88 1.61 1.46 1.37 1.24 1.16 1.11 1.07 1.01 3.95 2.48 2.00 1.68 1.52 1.42 1.28 1.19 1.14 1.10 1.04 7. Duty Cycle SF4 8-10 Hours per Day 1.0 11-16 Hours per Day 1.1 16-24 Hours per Day 1.2 Selection Procedure Step 1: Determine Basic Requirements Before attempting to select a specific Conveyor Chain determine the following as accurately as possible: 1. Type of Conveyor: Note whether the material to be conveyed is unit or bulk and whether the chain will carry the material weight directly or will it be supported by a deck or in a trough. 2. Class of Chain: Select a class of chain (Roller Conveyor, Steel Bushed, Welded Steel, etc.) 3. Estimate W: This includes the total weight per foot of all chain, attachments, slats, etc. on the conveyor and is given in lbs/ft. 4. Determine Dimensions: This includes the center distance in feet, and for inclined conveyors, the angle of incline (u) or height (A) and width (B). 5. Conveyor Speed (S): This should be determined in ft/min. 6. Weight of Material Conveyed (M): This value should be determined in lbs/ft on the conveyor. Note that often the designer specifies a through put or capacity for the conveyor. In such cases the value M needs to be calculated as follows: Bulk Materials with capacity given in Tons/hour (Q): M=(33.3xQ)/S Unit Materials with capacity given in units per hour (R) determine the weight per unit (m) and use: (M=(Rxm)/(60xS) 8. 8.62 3.62 2.56 2.03 1.78 1.63 1.47 1.34 1.27 1.22 1.15 6.20 2.94 2.21 2.05 1.84 1.61 1.48 1.40 1.34 1.26 Ta b l e 1 1 : R o l l e r / B u s h i n g Bearing Pressure Bushing - Roller Material Combination Carburized Carburized Steel Steel Carburized Thru Hardened Steel Steel Carburized Plastic Steel Thru Hardened Thru Hardened Steel Steel Thru Hardened Plastic Steel Allowable Bearing Pressure 750 psi 700 psi 250 psi 700 psi 250 psi Determine Friction Coefficients (f): From Tables 2-4 (page 25) determine the appropriate friction coefficients. Also consult the formulas on page 26 for additional assistance in determining the friction coefficients. Determine Service Factors (SF): (see Table 10). Service Factor is given by: SF=SF1 x SF2 x SF3 x SF4 9. Determine Number of Teeth for Sprockets: Use Table 9 and select number of teeth by reading down the chain speed column and finding the value nearest to 1.00 10. Determine Speed Correction Factor (SC): (See Table 9). 11. Determine # of Chain Strands Factor (NS): (See Table 8). Step 2: Calculate Conveyor Pull Use the appropriate formula on the page 26 to calculate total conveyor pull (P). Step 3: Calculate Design Conveyor Pull The Design Conveyor Pull (DP) is given by: DP=P x SF x SC x NS Step 4: Calculate Chain Tension The calculated Chain Tension (T) is given by: T=DP/Tot al Number of Ch ain Str ands Step 5: Select Chain and Recalculate Chain Tension (T) Select a chain that has a higher rated working load (found in the dimension tables) than the calculated chain tension. Recalculate Chain Tension (T) using the correct values for chain and attachment weights (W) to verify the selection. Step 6: Verify Roller/Bushing Bearing Pressure for Roller Conveyor Chains Only. Determine the bearing pressure (BP) between the Roller ID and the Bushing OD by: BP=Load Per Roller / Bear i n g A r e a Load Per Roller=(M+W)/[(12/Pitch)xNumber of Strands] Bear i n g A r e a=Bushing OD x (Inside Width-.063) BP should be less than found in Table 11 for material combo. 27

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