Selection of Idler Roller Conveyor
Follow simple steps for as to How to select conveyor idler to move material load through rollers on belt conveyor system:-
Step 1 of HIC Universal conveyor idler Selection:
Conveying Capacity of belt conveyor assessment- Cross-sectioned Area (A) multiplied by conveying speed (V) gives result of conveying capacity of belt conveyor, further multiplied by slope Correction factor ranging from 0.8 to 1.0 .
Qv (m3 /h) = A (m2) x V (m/s) x 3600 x (Slope Correction Factor)
Qm (TPH) = A (m2) x V (m/s) x 3.6 x Material Density (kg/m3) x (Slope Correction Factor)
Step 2 of HIC Universal conveyor idler Selection:
Troughing Angle of Idlers choice based on conveyed Material Class – Greater carrying capacity for a given belt width is achieved using idlers with end-roll sets at steeper troughing angles of 35o and 45o degree angles in place of normal 20o angle. Though, minimum transition distances (1.0 belt width to 9b as per trough depth and rated tension) for idler adjacent to terminal pulleys need to be followed if using steeper troughing angles and higher transverse flexibility fabric carcass design conveyor belting by opting very high tensile rating belt with lesser number of plies.
Step 3 of HIC Universal conveyor idler Selection:
Belt Width choice based on Lump size and Peak Load vis-à-vis- Belt Speed - Belt width between 500 mm (max lump size of 4”) to 2400 mm (max lump size of 18”) based on 20o angle of surcharge and surge or peak load (TPH) being 80% full cross-sectional load area of the belt and belt speed 100 FPM to 750 Feet Per Minute may be chosen. Belt width calculation method:-
i) Capacity conversion to cubic feet per hour from TPH :
FT3 / HR = TPH x 2000 LBS/TON
Material Density (LBS/ FT3) x 80 %
ii) Capacity Equivalent at a belt speed of 100 FPM :
Capacity equivalent = FT3 / HR = 100 FPM
Belt Speed FPM (chosen)
iii) Minimum or higher Belt Width selection based on correct surcharge and troughing angle.
iv) Design Belt Speed or final FPM:
design Speed FPM = FT3 / HR (Method i) x 100 FPM
selected BW Capacity FT3 /HR @ 100 FPM (Method iii)
Higher speeds above 350 FPM requires special chute design and tripper drive, thus idlers designing involves complex procedure.
Step 4 of HIC Universal conveyor idler Selection:
Adjusted Load of Idlers computation- Actual load and then Adjusted load of troughing carrying idler be calculated as stated:
Actual Idler Load, IL = Wb ( conveyor Belt weight, kg/m) + Wm ( material weight, kg/m)
x Si ( Idler Spacing, between 0.6 to 1.5 m )
Adjusted Load, AL = IL x K1 ( lump adjustment factor, bet. 1.0 to 1.4 ) x K2 ( maintenance factor, bet.1.0 to 1.15 ) x K3 ( service factor, bet. 0.8 to 1.2 ) x K4 (belt correction factor, bet. 0.8 to 1.05) + IML ( force due to idler height deviation )
Step 5 of HIC Universal conveyor idler Selection:
Pipe Series and Bearing Load Ratings of Idlers choice- Approximate Load ratings with rigid frame based on min. 30,000 operating hours at 500 RPM at trough angle of 20o with three equal length rolls of ‘B’ class Pipe series carrying roller idlers with ball bearings being 185 kgs up to 800 mm belt width, 160 kgs >800 up to 1000 mm BW, 150 kgs >1000 up to 1200 mm conveyor belt-width.
‘C’ series, ‘D’ series pipe rollers with tapered roller bearings for heavy duty and corrosive environments are selected for 60,000 operating hours or more trouble-free movement.
RPM = Belt Speed ( FPM ) x 12
Roll Diameter (inch) x 3.146 ( л )
Larger diameter roller sizes choice implies increased bearing life and idler-wear life. Similarly, larger shaft thickness choice also influences more load carrying capacity as higher capacity bearing size is used, thereby increases overall idlers running life.
Load Ratings for Idlers
The Following conveyor belt capacity charts show tons per hour (TPH) based on material weighing 100 lbs. per cubic foot, 20° material surcharge angle with three equal length rolls on troughing idlers.
Load Ratings for CEMA Idlers - Rigid Frame (Lbs)
1. TROUGHING IDLER LOAD
RATINGS ARE FOR THREE EQUAL LENGTH ROLLS.
2. LOAD RATINGS ALSO APPLY FOR IMPACT ROLLS.
3. TROUGHING IDLER LOAD
RATINGS ARE BASED ON A LOAD DISTRIBUTION OF 70% ON CENTER ROLL AND 15% ON EACH END ROLL FOR ALL TROUGH ANGLES.
Picking Idler Load Ratings (Lbs.)
|Belt Width||CEMA C||CEMA D|
Live Shaft Idler Load Capacities (Lbs.)
|Belt Width||CEMA C||CEMA D|
Conveyor Idler Bearing Load as per CEMA
|Belt width mm||load on center bearings kg*||shaft dia. mm|
|S 500||S 1000||S 1500|
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