Conveyor design The layout of a conveyor varies with the type of chain used. A typical layout is shown below. Goods should be conveyed on the tension side of the chain, and the slack (return) side should be supported by guide rails with sloped ends to prevent chain vibration and conveyor pulsation. 2-1 Guide rail The guide rail consists of the conveyor frame and liner. The liner sides with the top chain to minimize frictional resistance and wear so the chains are protected and driving power can be minimized.
Step 7
Determine chain size Multiply the maximum chain tension (T) by the speed coefficient (k 1 ) taken from Table VII and verify that the following equation is satisfied.
T X k 1 Chain maximum allowable load .................. Formula 5
When the maximum allowable load is insufficient, it can be corrected by using top plates with narrower width and increasing the number of chain strands, or by splitting into many short conveyors.
Table VII: Speed Coefficient (k 1 )
Chain Speed (ft./min.)
Speed Factor (k 1 )
0 50 50 100 100 160 160 230 230 300 300 360 360 400
1.0 1.2 1.4 1.6 2.2 2.8 3.2
2-2 Location of guide rails and sprocket When the chain engages with the sprocket, the chain itself moves up and down slightly due to the polygonal effect of the sprocket. Therefore, the guide rail on the loaded side must be positioned so that the chain is horizontal when at the highest level. Guide rail installation dimension (A) is determined from the following equation.
T : Chain tension (lbs.) M : Weight of material conveyed per ft. (lbs./ft.) w : Chain weight (lbs./ft.) L : Center distance between sprockets (ft.) l : Distance not loaded (ft.) L’ : Distance of the material sliding on the chain for storage (L ’ =0 when items and chain are not slipping) f 2 : Coefficient of friction between the top plate and liner (See page B-77, Table IV)
pitch diameter of sprocket A = ––––––––––––––––––––– + B (inch) 2
Chain Type
B C
TS • TRU • TKU • TN • TNU .433 TT, TTU .157 .197 TP-II • TPU, TTP, TTPF .157 TP-I
f 3
: Coefficient of friction between goods moved and top plate (See page B-77, Table V) : Speed coefficient (See Table VII) : Angle factor (See page B-77, Table VI) : Length factor (See page B-77, Table VI)
1.496
k 1 k 2 k 3
R : Radius at corner (ft.) S : Chain speed (ft./min.) η
: Mechanical transmission efficiency for drive unit
HP : Power required
Note: Please refer to page B-73 for the RS Plastic chain
B-78
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