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 35^o and 45^o degree angles in place of normal 20^o 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 20^o 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)

Idler Class	Belt Width (Inches)	Single Roll Return	Two Roll Vee
Idler Class	Belt Width (Inches)	20°	35°	45°
CEMA B Idlers	18	410	410	220
	24	410	410	190
	30	410	410	165
	36	410	410	155
	42	390	363	140
	48	380	353	125

Ratings Based on Min L10 of 30,000 Hours at 500 RPM

CEMA C Idlers	18	900	900	475
	24	900	900	325
	30	900	900	250
	36	900	837	200
	42	850	791	150
	48	800	744	125
	54	750	698	*
	60	700	650	*
	66			*

CEMA D Idlers	24	1,200	1,200	600
	30	1,200	1,200	600
	36	1,200	1,200	600
	42	1,200	1,200	500
	48	1,200	1,200	425
	54	1,200	1,116	375
	60	1,150	1,070	280
	66			215
	72	1,050	977	155
	78			125

NOTES FOR TABLE:

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
24	475	600
30	475	600
36	325	600
42	250	600
48	200	530
54	150	440
60	125	400
72		280
84
96

Live Shaft Idler Load Capacities (Lbs.)

Belt Width	CEMA C	CEMA D
18	1,200
24	1,200	1,400
30	1,200	1,400
36	1,200	1,400
42	1,100	1,400
48	1,000	1,275
54	875	1,150
60	780	1,000
72		850
84

Conveyor Idler Bearing Load as per CEMA

Belt width mm	load on center bearings kg*			shaft dia. mm
Belt width mm	S 500	S 1000	S 1500	shaft dia. mm
450	11	23	34
600	20	40	60
750	31	63	94
900	45	90	135
				20
1050	61	123	180
1200	80	160	240	25
1350	101	203	304
1500	125	250	375
1800	180	360	540	30
2100	245	490	735
2400	320	640	960
				40

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HIC International Co Inc.

Selection of Idler Roller Conveyor