1、CEMA STANDARD 502-2004CONVEYOR EQUIPMENT MANUFACTURERS ASSOCIATIONCEMASTANDARDNO. 502-2004Bulk Material Belt ConveyorTroughing and Return IdlersSelection and DimensionsISBN 1-891171-52-6Revision ofCEMA Standard 502-2001CEMA STANDARD 502-2004For Information on Company Membershipvisit the CEMA Web Sit
2、e athttp:/www.cemanet.orgConveyorChainCEMA ORGANIZATIONAL CHARTControls PalletizersMeet in March and/or SeptemberConferenceStrategic PlanningInsuranceMeetingsMembershipPublic RelationsStatisticsSafety SteeringFinance and BudgetPast PresidentsBulk HandlingSectionCommitteesUnit HandlingSectionEngineer
3、ing ConferenceConveyor ChainPerformance TerminologyUnit Handling StandardsIdlersPulleysBeltSystemsScrewConveyorsBeltManualAccessoriesSafety ControlsTerms andDefinitionsInternationalStandardsMeetsEach JuneScrewConveyorsBulk HandlingComponentsand SystemsGeneral Bulk Handling SectionBulkAccessoriesUnit
4、 Handling Conveying SectionCOMMITTEES BOARD OF DIRECTORS OFFICERSSAFETY NOTICEThe Conveyor Equipment Manufacturers Association has developed Industry Standard Safety Labelsfor use on the conveying equipment of its member companies.The purpose of the labels is to identify common and uncommon hazards,
5、 conditions, and unsafepractices which can injure, or cause the death of, the unwary or inattentive person who is workingat or around conveying equipment.The labels are available for sale to member companies and non-member companies.A full description of the labels, their purpose, and guidelines on
6、where to place the labels on typicalequipment, has been published in CEMAs Safety Label Brochure No. 201. The Brochure is availablefor purchase by members and non-members of the Association. Safety Labels and Safety LabelPlacement Guidelines, originally published in the Brochure, are also available
7、free on the CEMAWeb Site at http:/www.cemanet.org/CEMA_Safety_Pg.htmPLEASE NOTE: Should any of the safety labels supplied by the equipment manufacturer becomeunreadable for any reason, the equipment USER is then responsible for replacement and locationof these safety labels.Replacement labels and pl
8、acement guidelines can be obtained by contacting your equipmentsupplier or CEMA.CEMA STANDARD 502-2004Prepared byThe Idler Committeeof theCEMA Engineering ConferenceCONVEYOR EQUIPMENT MANUFACTURERS ASSOCIATION6724 Lone Oak BlvdNaples, Florida 34109(239) 514-3441Fax: (239) 514-3441E-Mail: cemacemanet
9、.orgWeb Site: http:/www.cemanet.orgStandard No. 502 - Copyright 2004Printed in the U.S.A.ISBN 1-891171-53-4Publication Date: February 20, 2004FOREWORDThis standard has been established to provide uniformity of clearance and mounting dimensions among the variousmanufacturers of conveyor belt troughin
10、g idler and return rolls.This standard assures the users of conveyor idlers interchangeability of complete idler assemblies but does notrestrict the manufacturer, who has complete freedom to design all parts of the idler according to its best engineeringjudgment.The various idlers are separated into
11、 nine different classes according to load ratings and roll diameters. There aresome overlaps because of wide variation in idler construction. All manufacturers must specify into which class theirparticular designs fall.It is hoped this standardization will eliminate requests for special idler design
12、s. Conformance with this standard willprovide better designs at lower cost.The 1998 edition added technical data for expanded belt widths on CEMA C, D, and E Rollers and Returns and thetables have all been reformatted to make the material easier to access.The 2001 edition has added technical data fo
13、r CEMA C, D, and E Picking Idlers, Live Shaft Idler Dimensions andLoad Capacities for Rubber Disc and Steel Tube Designs, and has modified the Idler Selection Procedures toinclude Impact Idler Selection.This 2004 edition has:1. Reformatted the tables for CEMA Class B,C,D, and E Troughing Idlers, Pic
14、king Idlers, and Return Idlersfor easier reference.2. Redrawn the Idler Diagrams to conform with the revised t ables.3. Added CEMA Class F Idlers.Bulk Material Belt Conveyor T roughing and Return Idlers - Selection and DimensionsCEMA STANDARD 502-2004DISCLAIMERThe information provided in this docume
15、nt is advisory only. These recommendations areprovided by CEMA in the interest of promoting safety in the work place.These recommendations are general in nature and are not intended as a substitute for athorough safety program. Users should seek the advise, supervision or consultation ofqualified en
16、gineers or other safety professionals.Any use of this document, the information contained herein, or any other CEMA publicationmay only be made with the agreement and understanding that the user and the userscompany assume full responsibility for the design, safety, specifications, suitability andad
17、equacy of the system component, or mechanical or electrical device designed ormanufactured using this information.The user and the users company understand and agree that CEMA, its member companies,its officers, agents and employees shall not be liable in any manner under any theory ofliability for
18、the user or users reliance on these recommendations.The users and the users company agree to release, hold harmless and indemnify CEMA,its member companies, successors, assigns, officers, agents and employees from anyand all claims of liability, costs, fees (including attorneys fees), or damages ari
19、sing in anyway out of the use of this information.CEMA and its member companies, successors, assigns, officers, agents and employeesmake no representations or warranties whatsoever, either express or implied, about theinformation contained in this document, including, but not limited to, representat
20、ions orwarranties that the information and recommendations contained herein conform to anyfederal, state or local laws, regulations, guidelines or ordinances.CEMA STANDARD 502-2004IDLER NOMENCLATUREThis standard provides uniform dimensional and load capacity information for several idler types as fo
21、llow:- Troughing Idlers, with equal length rolls.- Picking Idlers, with unequal length rolls.- Return Idlers, with a dingle steel roll but typicaally available with rubber discs.- V Return Idlers, with a pair of steel rolls but typically available with rubber discs.- Live Shaft Idlers with steel or
22、rubber surfaces.Nomenclature and selection methods have been developed to provide a realistic and versatile means of classifying idlers.The Idler classifications and historic series are tabulated below.CEMA Class Former Series Roll Diamether Belt Width DescriptionA4 STANDARD WITHDRAWN - OCTOBER 1, 1
23、996 Light DutyA5 STANDARD WITHDRAWN - OCTOBER 1, 1996 Light DutyB4 II 4” 18” through 48” Light DutyB5 II 5” 18” through 48” Light DutyC4 III 4” 18” through 60”C6 III 5” 18” through 60”C6 IV 6” 24” through 60”D5 None 5” 24” through 72” Medium DutyD6 None 6” 24” through 72”E6 V 6” 36” through 96” Heav
24、y DutyE7 VI 7” 36” through 96”F6 New 6” 60” through 96” Heavy DutyF7 New 7” 60” through 96”F8 New 8” 60” through 96”TABLE OF CONTENTSIdler Designation Type of Angle PageCEMA B4, B5 Troughing 20 35 45 2CEMA C4, C5, C6 Troughing 20 35 45 3CEMA D5, D6 Troughing 20 35 45 4CEMA E6, E7 Troughing 20 35 45
25、5CEMA F6, F7, F8 Troughing 20 35 45 6CEMA C4, B5 Flat Return 7CEMA C4, C5, C5 Flat and V Returns 10 O.D. = 5“ O.D. = 5“ O.D. = 6“ Steps 1, 2 and 3:Select idler class by comparing calculated idler load with idler load ratings (CIL and CILR) from Tables 2-11through 2-14. Select impact idler class, if
26、necessary, as shown in Step 3. CEMA idler manufacturers have standarddesigns meeting these load ratings and dimensional standards shown in tables listed in this publication.Bearing L10Life Correction; Steps 4, 5, and 6:Factors K2 (Fig. 2.5) and K3A (Fig. 2.6) are multiplying factors used to adjust b
27、asic L10life rating of idler classselected. Factor K2 is based on percent of idler load and K3A is factor for actual roll speed (RPM). Factor K3B(Fig. 2.7), step 6 is an optional step showing advantage of using larger diameter rolls. It can be used as amultiplier to save repeating step 5 if a larger
28、 diameter roll is used.Determine Potential Idler Life; Step 7:Factors K4A (Fig. 2.8), K4B (Fig. 2.9) and K4C (Fig. 2.10) show conditions which will affect idler life and areindependent of bearing L10life, idler load and idler class. Use these figures to evaluate the potential expectedidler life. Con
29、tact your CEMA idler manufacturer for recommendations.Step No. 1 - Troughing Idler Series SelectionCalculated Idler Load (lbs.) = CIL = (WB + (WM x K1) x SI) + IMLWhere:WB = Belt weight (lbs./ft.) use actual or estimate from Table 2-1WM = Material weight (lbs./ft.) = (Q x 2000) / (60 x V)Q = Quantit
30、y of material conveyed (Tons per hour)V = Design belt speed (FPM)SI = Spacing of idlers (ft.)K1 = Lump adjustment factor (see Table 2-2)Note: Actual weight of lump should be compared with WM value.In situations it may be necessary to use actual lump weightas WM. Contact your CEMA idler manufacturer
31、if you havedoubts as to which value to use.IML = Idler misalignment load (lbs.) due to idler height deviation andbelt tension = (D x T) / (6 x SI) where:D = Misalignment (inches)T = Belt tension (lbs.)SI = Idler spacing (feet)When an idler is higher than adjacent idler, acomponent of belt tension wi
32、ll add load to that idler.The amount of height deviation can vary with theinstallation and type of idler. CEMA publication on “Conveyor Installation Standards“ ( also found in Appendix D,“Belt Conveyors for Bulk Material,“ Fifth Edition or later) lists recommendations on structure misalignment).Use
33、CIL and select proper series of idler from T ables 2-11 through 2-15.CIL value should be equal to or less than idler rating.19.CEMA STANDARD 502-200420.This troughing idler selection procedure for calculated idler load does not include impact force on idler at loadingpoints or the effect of belt tra
34、nsitions (head and tail pulley) on idler load. See Step No. 3 for impact idler seriesselection. Contact your CEMA idler manufacturer for idler series selection for other loading conditions.Table 2-1 WB-Estimated average belt weightmultiple and reduced ply belt s. lbs./ft.1. Steel cable belts - incre
35、ase above value by 50%.2. Actual belt weights vary with different constructions, manufacturers, cover gauges,etc. Use the above values for estimating. Obtain actual values from the belt manufacturerwhenever possible.Table 2-2 K1-Lump adjustment factorStep No. 2 - Return idler series selectionCalcula
36、ted Idler Load (lbs.) = CILR= (WB x SI) + IMLUse CILRand select proper series of idler from T ables 2-11 through 2-14. CILRshould be equal to or lessthan return idler rating.30-74 75-129 130-20018 3.5 4 4.524 4.5 5.5 630 6 7 836 9 10 1242 11 12 1448 14 15 1754 16 17 1960 18 20 2272 21 24 2684 25 30
37、3396 30 35 38Material Carried, lbs./cu. ft.Belt Width (inches (b)50 75 100 125 150 175 2004 1.0 1.0 1.0 1.0 1.1 1.1 1.16 1.0 1.0 1.0 1.1 1.1 1.1 1.18 1.0 1.0 1.1 1.1 1.2 1.2 1.210 1.0 1.1 1.1 1.1 1.2 1.2 1.212 1.0 1.1 1.1 1.2 1.2 1.2 1.314 1.1 1.1 1.1 1.2 1.2 1.3 1.316 1.1 1.1 1.2 1.2 1.3 1.3 1.318
38、1.1 1.1 1.2 1.2 1.3 1.3 1.4Material Weight, lbs./cu. ft.Maximum Lump Size (inches)CEMA STANDARD 502-200421.Step No. 3 - Impact Idler Series SelectionFor homogeneous material without lump s:Impact Force (lbs) = F = (0.1389) Q HWhere:Q = Rate of flow (ST / hr)H = Height of fall (ft)The calculated impa
39、ct force is then multiplied by an impact idlerspacing factor, f (Table 2-3), to determine the impact force on one idler.Unit Impact Force (lbs) = Fu= F (f)Use this unit impact force, Fu, and select proper series of impact idler from Tables 2-11 through 2-14.Fushould be equal to or less than idler ra
40、ting.For material containing large lumps:Impact Force (lbs) = F = W + 2kWHWhere:W = Weight of lump (lbs)H = Height of fall (ft)k = Spring constant for specific idler type (lbs / ft)(CONSULT IDLER MANUFACTURER)Use calculated energy rating, WH, and maximum lump size to selectproper series of impact id
41、ler from Table 2-4. Both WH and lump sizeshould be equal to or less than energy rating and maximum lumpsize.Note: Both cases (material without lumps and material containing large lumps) should always be consideredand the heavier duty idler selected to insure adequate impact resistance capabilities.T
42、able 2-3 Impact Idler Spacing FactorImpact Idler Spacing, SI Impact Idler Spacing Factor, f1 - 0“ 0.51 - 6“ 0.72 - 0“ 0.9 2 - 0“ 1Table 2-4 Minimum Energy Ratings for Imp act IdlersCEMA Series WH (lbs-ft) Maximum Lump Size (in.)B40 4C 160 6D 240 8E 460 12F 870 183-Roll Rubber Impact Idlers (Equal Le
43、ngth Rolls)CEMA STANDARD 502-200422.Step No. 4 - K2 = Effect of load on predicted bearing L10lifeWhen Calculated Idler Load (CIL) is less than CEMA load rating of series idler selected, the bearing L10life willincrease.Figure 2.5 K2 = Effect of Load on Predicted Bearing L10LifeCIL (Calculated Idler
44、Load)Idler Load RatingStep No. 5 - K3A = Effect of belt speed on predicted bearing L10lifeCEMA L10life ratings are based on 500 rpm. Slower speeds increase life and fasterspeeds decrease life. Figure 2.4 shows this relationship.Figure 2.6 K3A = Effect of Belt Speed on Predicted Bearing L10LifeRoll S
45、peed (rpm)Step No. 6 - K3B = Effect of roll diameter on predicted bearing L10life.For a given belt speed, using larger diameter rolls will increase idler L10life. Figure 2.5 depicts L10life adjustmentsfor various roll diameters using 4” diameter as a value of 1.0. Percent life increase can be calcul
46、ated for each rolldiameter increase.Figure 2.7 K3B = Effect of Roll Diameter on Predicted Bearing L10Life(Based on same belt speed)Note: In addition to increased predicted bearing L10life, larger diameter rolls can increase idler wear life.0.01.02.03.04.05.06.07.08.09.010.050 100 200 300 400 500 850
47、K3A Factor1.001.251.501.754567K3B Factor1.00.5 0.6 0.7 0.8 0.9 1.0K2Factor10.08.06.04.02.00.0Ball BearingRoller BearingExample: = 1.20 or 20% increase in L10life.1.5 for 6“ dia1.25 for 5“ diaRPM =Belt Speed (fpm) x 12Roll Dia. (in.) x pCEMA STANDARD 502-200423.Figure 2.10: K4C = Effect of operating
48、temperature on potential idler lifeTemperature (degrees F)Step No. 7 - K4 = Environment al, maintenance and other special conditionsFigure 2.8: K4A = Effect of maintenance on potential idler lifeFigure 2.9: K4B = Effect of environment on potential idler lifeFigure 2.10: K4C = Effect of operating tem
49、perature on potential idler lifeBased on collective application experience by CEMA idler manufacturers these conditions are very important indetermining potential idler life. However, exact mathematical basis is very subjective so contact your CEMA idlermanufacturer for assistance or for any unusual conditions not listed.Figure 2.9: K4B = Effect of environment on potential idler lifeGOOD FAIR POORFigure 2.8: K4A = Effect of maintenan
