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Fono: 56‐2‐22
S PROJECT
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FOR BELT CONVEYORS HANDLING BULK MATERIALS
CONVEYOR INSTALLATIONSTANDARDS
CONVEYOR EQUIPMENT MANUFACTURERS ASSOCIATION
THIS PUBLICATION IS
APPENDIX D OF THE
SIXTH EDITION OF THE
CEMA BELT BOOK
“BELT CONVEYORS FOR
BULK MATERIALS”
2005
WHILE THE CONTENT IS
IDENTICAL, IT HAS BEEN
RE-FORMATTED TO
CONFORM TO CEMASTYLE GUIDELINES FOR
STAND ALONE
DOCUMENTS.
For Information on Company Membershipvisit the CEMA Web Site at
http://www.cemanet.org
CEMA ORGANIZATIONAL CHART
SAFETY NOTICE
The 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, conditions, and unsafepractices which can injure, or cause the death of, the unwary or inattentive person who is working ator 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 where to place the labels on typicalequipment, has been published in CEMA’s 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 free on the CEMA WebSite at http://www.cemanet.org/CEMA_Safety_Pg.htm
PLEASE 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 location ofthese safety labels.
Replacement labels and placement guidelines can be obtained by contacting your equipment supplieror CEMA.
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Meets Each June
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COMMITTEES BOARD OF DIRECTORS OFFICERS
INTRODUCTION
CONVEYOR STRINGER ALIGNMENT
PARALLEL
STRAIGHTNESS
SQUARENESS
LEVEL
PULLEY AND SHAFT ALIGNMENT
REDUCER/MOTOR BASE INSTALLATION TOLERANCES
FABRICATED STRUCTURAL BASES
CONCRETE SUPPORTS
STRUCTURAL STEEL SUPPORTS
FLEXIBLE COUPLING ALIGNMENT
ANGULAR ALIGNMENT
PARALLEL ALIGNMENT
AXIAL ALIGNMENT
IDLER ALIGNMENT
BELT ALIGNMENT
EMPTY RUN-INFULL LOAD RUN-INHELPFUL HINTS
SKIRTBOARD ADJUSTMENT
IDLER LUBRICATION
MANUFACTURER'S RECOMMENDATION
TYPE OF LUBRICANT
IDLER CONSTRUCTION
SAFETY
ADJUSTMENTS
SAFETY LABELS
SAFETY LABEL PLACEMENT GUIDELINE - BH-1
i.
CONVEYOR INSTALLATION STANDARDS FOR BELT CONVEYORS HANDLING BULK MATERIALSALSO, APPENDIX D, SIXTH EDITION, BELT CONVEYORS FOR BULK MATERIALS
PREPARED BY
THE BELT BOOK COMMITTEE
OF THE
BULK HANDLING SECTION
OF THE
CEMA ENGINEERING CONFERENCE
DISCLAIMER
THE INFORMATION PROVIDED IN THIS DOCUMENT IS ADVISORY ONLY. THESE RECOMMENDATIONS ARE PROVIDED BY CEMA INTHE INTEREST OF PROMOTING SAFETY IN THE WORK PLACE. THESE RECOMMENDATIONS ARE GENERAL IN NATURE AND ARE NOT
INTENDED AS A SUBSTITUTE FOR A THOROUGH SAFETY PROGRAM. USERS SHOULD SEEK THE ADVISE, SUPERVISION OR CONSULTATION
OF QUALIFIED ENGINEERS OR OTHER SAFETY PROFESSIONALS. ANY USE OF THIS DOCUMENT, THE INFORMATION CONTAINED
HEREIN, OR ANY OTHER CEMA PUBLICATION MAY ONLY BE MADE WITH THE AGREEMENT AND UNDERSTANDING THAT THE USER
AND THE USER’S COMPANY ASSUME FULL RESPONSIBILITY FOR THE DESIGN, SAFETY, SPECIFICATIONS, SUITABILITY AND ADEQUACY
OF THE SYSTEM COMPONENT, OR MECHANICAL OR ELECTRICAL DEVICE DESIGNED OR MANUFACTURED USING THIS INFORMATION.THE USER AND THE USER’S COMPANY UNDERSTAND AND AGREE THAT CEMA, ITS MEMBER COMPANIES, ITS OFFICERS, AGENTS
AND EMPLOYEES SHALL NOT BE LIABLE IN ANY MANNER UNDER ANY THEORY OF LIABILITY FOR THE USER OR USER’S RELIANCE ON
THESE RECOMMENDATIONS. THE USERS AND THE USER’S COMPANY AGREE TO RELEASE, HOLD HARMLESS AND INDEMNIFY CEMA,ITS MEMBER COMPANIES, SUCCESSORS, ASSIGNS, OFFICERS, AGENTS AND EMPLOYEES FROM ANY AND ALL CLAIMS OF LIABILITY,COSTS, FEES (INCLUDING ATTORNEY’S FEES), OR DAMAGES ARISING IN ANY WAY OUT OF THE USE OF THIS INFORMATION. CEMAAND ITS MEMBER COMPANIES, SUCCESSORS, ASSIGNS, OFFICERS, AGENTS AND EMPLOYEES MAKE NO REPRESENTATIONS OR
WARRANTIES WHATSOEVER, EITHER EXPRESS OR IMPLIED, ABOUT THE INFORMATION CONTAINED IN THIS DOCUMENT, INCLUDING,BUT NOT LIMITED TO, REPRESENTATIONS OR WARRANTIES THAT THE INFORMATION AND RECOMMENDATIONS CONTAINED HEREIN
CONFORM TO ANY FEDERAL, STATE OR LOCAL LAWS, REGULATIONS, GUIDELINES OR ORDINANCES.
CONVEYOR EQUIPMENT MANUFACTURERS ASSOCIATION
6724 LONE OAK BLVD
NAPLES, FLORIDA 34109WEB SITE: WWW.CEMANET.ORG
COPYRIGHT 2005PRINTED IN THE U.S.A.
ISBN 1-891171-63-1
ii.
CONVEYOR INSTALLATION STANDARDS FOR BELT CONVEYORS HANDLING BULK MATERIALSALSO, APPENDIX D, SIXTH EDITION, BELT CONVEYORS FOR BULK MATERIALS
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CONVEYOR INSTALLATION STANDARDS FOR BELT CONVEYORS HANDLING BULK MATERIALSALSO, APPENDIX D, SIXTH EDITION, BELT CONVEYORS FOR BULK MATERIALS
INTRODUCTION
A trouble-free belt conveyor operation is the product of three properly executed stages of developmentfollowed by an effective maintenance program.
1. Design2. Manufacturing3. Installation
Less than satisfactory performance in any of these developmental stages will negatively impact all others,resulting in unanticipated operating problems.
CEMA Standards and Belt Conveyors for Bulk Materials already addressed many of the design andmaintenance considerations critical to proper operation. It is not our intent to specify minimum levels ofmanufacturing quality. Indeed, it is the responsibility of each manufacturer to produce a product ofwhich he and the user agree are suitable for the intended use.
This document will specify minimum standards for acceptable tolerances for structural and mechanicalerection and installation of belt conveyors. In addition, it will provide helpful suggestions that can beutilized to meet or exceed these standards. Each item will be addressed in the sequence in which it isencountered in the field.
NOTES· It is important that ANSI lockout procedures be followed when making adjustments to bringconveyor machinery into tolerance (ref: ASME B15.1, B20.1, and ANSI Z244.1).
· All mechanical tolerances and benchmarks should be documented by millwrights.
CONVEYOR STRINGER ALIGNMENT
Trusses and channel frame conveyor stringers must be installed parallel, straight, square, and level toallow proper belt training. During installation, dimensional checks shall be made to insure that the followingtolerances in the idler carrying chords are not exceeded.
Note: These tolerances are guidelines for design / manufacture to facilitate proper idler and belt alignmentin accordance with the Idler Alignment section of this standard. The overriding issue is idler and beltalignment as opposed to structural alignment.
PARALLEL
A maximum tolerance of +/- 1/8” inch shall be allowed for the “back to back” dimension inchannel frame or angle stringers. Similarly, +/- 1/8”inch shall be allowed between webs of I-beams, wide flange beams, or tees when used as truss chords (Figure 1).
FIGURE 1Maximum tolerance for back to back parallel dimension
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CONVEYOR INSTALLATION STANDARDS FOR BELT CONVEYORS HANDLING BULK MATERIALSALSO, APPENDIX D, SIXTH EDITION, BELT CONVEYORS FOR BULK MATERIALS
CONVEYOR STRINGER ALIGNMENT CONTINUED
STRAIGHTNESS
The maximum allowable lateral offset in conveyor stringers shall be 1/8” inch in 40’ feet of length(Figure 2).
FIGURE 2Maximum allowable offset in stringers
SQUARENESS
A check on squareness can be made by comparing diagonal measurements between idlers asshown in Figure 3.
FIGURE 3Conveyor frame and idler alignment
Lines A and B must be within 1/8” to assure conveyor frame squareness. Return idlers should,likewise, be installed level and parallel to the head and tail pulleys.
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CONVEYOR INSTALLATION STANDARDS FOR BELT CONVEYORS HANDLING BULK MATERIALSALSO, APPENDIX D, SIXTH EDITION, BELT CONVEYORS FOR BULK MATERIALS
LEVEL
The two idler support members shall be level within1/8”regardless of belt width. In addition, the eleva-tion of stringer above support structure shall be held within +/- 1/4” (Figure 4).
FIGURE 4Idler support members level requirements
NOTE:Designers and fabricators must compensate for mill tolerance of members to satisfy these requirements
PULLEY AND SHAFT ALIGNMENT
Except for special purpose applications (such as turnover exit), all belt conveyor pulleys should be setlevel, and the shaft centerline should be perpendicular to the centerline of the belt. Significant departurein alignment will result in unnecessary thrust load on bearings, accelerated and uneven pulley laggingwear, and belt training problems.
It is most convenient to field align pulleys after supporting steel is secured and before belting is installed.After alignment, it is good practice to matchmark bearing housing and supporting steel to enable realignmentif disturbed for any reason. Intentional misalignment should not be used as a means to counteract othermisalignment forces for training the belt.
Because of pulley manufacturing tolerances, alignment measurements should be taken on the shaft andnot on pulley elements. By use of adjustable bearing stops (commonly supplied by the conveyormanufacturer) and full bearing surface shim packs (commonly supplied by the erector), the followingalignment tolerances can be reasonably achieved:
Using a level and checking both sides of the pulley, shaft elevations at the bearings should be set within 1/32 of an inch (Figure 5).
CONVEYOR STRINGER ALIGNMENT CONTINUED
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CONVEYOR INSTALLATION STANDARDS FOR BELT CONVEYORS HANDLING BULK MATERIALSALSO, APPENDIX D, SIXTH EDITION, BELT CONVEYORS FOR BULK MATERIALS
FIGURE 5Shaft elevation settings
Measuring from a line constructed perpendicular to the conveyor centerline, the shaft centerline shouldnot deviate greater than +/- 1/32 of an inch at the bearings (Figure 6). Because of pulley locations andaccess thereto, it is common practice to utilize offset lines and plumb bobs to make these measurements.
PULLEY AND SHAFT ALIGNMENT CONTINUED
FIGURE 6Shaft alignment with conveyor centerline
NOTE: See Figure 3 for Squareness Check.
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CONVEYOR INSTALLATION STANDARDS FOR BELT CONVEYORS HANDLING BULK MATERIALSALSO, APPENDIX D, SIXTH EDITION, BELT CONVEYORS FOR BULK MATERIALS
When pulleys are mounted on shafts by the equipment supplier, they shall be secured to the shaft inaccordance with the recommended practice of the locking element manufacturer. When supplied separately,they should be located on the shaft +/- 1/8 of an inch of the position shown on the drawings.
If pulleys and shafts are field assembled or repositioned, pulley manufacturer recommendations must befollowed to avoid dishing of end discs and residual end disc pre-stress.
With some locking elements, it may be necessary to check and tighten clamping bolts several times toinsure security of hub and shaft assembly. Manufacturer’s recommendations should be followed withregard to checks and bolt torques.
Pulleys, shafts, bearings, and supporting steel may be shipped in various degrees of preassembly. Due tomanufacturing and erection tolerances, final bearing setting should be done in the field after supportingsteel has been secured.
Procedures and tolerances for bearing settings should be obtained from the bearing manufacturer’s catalogs.Improper setting of both fixed and expansion type bearings may result in thrust pre-load, causing prematurebearing failure.
REDUCER/MOTOR BASE INSTALLATION TOLERANCES
Characteristic of all operating mechanical apparatus, correct manufacturing and installation alignmenttolerances are necessary to prolong operating life and prevent unnecessary breakdowns. Also, since manyreducer manufacturers do not factory oil their reducers, it is imperative that oil levels be checked andmaintained by field personnel.
Reducer/motor base installation guidelines generally fall into two categories, concrete or structural steel.Either should be sufficiently rigid to minimize vibration and to maintain alignment between the motor andthe driven equipment within the manufacturer’s recommended tolerances. Base application informationmay apply to either motors or reducers, or to both in combination.
FABRICATED STRUCTURAL BASES
Structural bases require a surface which, if not flat, can be shimmed to proper position in the structure,using .003 inch to .005 inch shim packs. After the base plate is secured, flatness should be verified andshims added, if necessary.
CONCRETE SUPPORTS
Concrete foundation-type supports are normally the most rigid and secure. However, the installation mustbe correct within certain limitations to provide acceptable tolerances in the final arrangement with aminimum of shimming.
Sole plates can provide a means of adjusting and aligning the motors and reducers or common bedplate toan acceptable tolerance prior to final grouting.
Reducer and motor mounting plate surface should be flat to tolerances acceptable to the manufacturer.The bottom of the sole plate needs no tolerance requirement inasmuch as the grout provides a fullingbearing surface.
PULLEY AND SHAFT ALIGNMENT CONTINUED
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CONVEYOR INSTALLATION STANDARDS FOR BELT CONVEYORS HANDLING BULK MATERIALSALSO, APPENDIX D, SIXTH EDITION, BELT CONVEYORS FOR BULK MATERIALS
PULLEY AND SHAFT ALIGNMENT CONTINUED
If the output from the reducer is direct-coupled to a driven unit, the reducer shaft centerline should be heldto a minus tolerance only, which would allow shimming by the erector if required. The same is true of themotor shaft in relation to the reducer input shaft.
It is mandatory that alignment checks be made after the installation is complete, but before operation.Misalignment should be no more than 50 percent of the misalignment tolerance allowed by the manufacturerof the coupling being aligned.
STRUCTURAL STEEL SUPPORTS
Although combination fabricated structural bases are normally built as a unit, it is not always necessary toprovide continuous support in the structural steel below the units; however, it is necessary to provide anintegrated and sufficiently rigid connection between reducer base and support steel to accommodateevery bolt hole.
The supporting structure must minimize deflection and distortion under load, preventing warping of themotor/reducer base and subsequent unacceptable misalignment.
FLEXIBLE COUPLING ALIGNMENT
Flexible couplings are used in conveyor drive trains to transmit torque from one rotating element to another.In doing so, they protect expensive driving and driven machinery from misalignment, shock loads, vibration,and thrust loads.
It is true that most couplings will operate under severe misalignment for a given period of time; however,the penalty is reduction in useful life. For this reason, manufacturers of couplings have establishedmisalignment tolerances that should be strictly adhered to during field assembly.
A prerequisite to proper alignment is a rigid and level base on which the drive and driven elements are tobe set. If they are to be mounted on a steel frame, a common base plate is necessary to prevent movementbetween independently supported steel members.
Prior to coupling installation, the installer must thoroughly familiarize himself with all of the manufacturer’spublished requirements of the motor, speed reducer, and couplings. Field breakdown and checking ofalignment during assembly to the support structure shall be accomplished using dial indicators, machinetest levels, or other means, with only commercial shim stock used for final alignment.
Three types of alignment must be checked: (1) Angular; (2) Parallel; (3) Axial.
ANGULAR ALIGNMENT (See figure 7)
Angular alignment is defined as the movement of the input and output halves of the coupling in such amanner as to permit a rocking and/or sliding action of the element that connects the coupling halves.
After the coupling halves have been mounted to the driver and driven shafts, the two units should bepositioned so that the distance between the coupling faces is equal to the “normal” coupling gap.
The coupling halves are then aligned by positioning a spacer block of thickness equal to the required gapbetween the faces. The spacer block should check gap at a minimum of 900 degree intervals. Once this isaccomplished, the gap should be measured with a feeler gauge.
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CONVEYOR INSTALLATION STANDARDS FOR BELT CONVEYORS HANDLING BULK MATERIALSALSO, APPENDIX D, SIXTH EDITION, BELT CONVEYORS FOR BULK MATERIALS
FLEXIBLE COUPLING ALIGNMENT CONTINUED
FIGURE 7Coupling angular alignment
PARALLEL ALIGNMENT (See Figure 8)
Parallel Alignment is defined as the movement of the input and output halves of the coupling in a waythat maintains parallelism between the faces of each coupling half but allows the shafts to occupyseparate center lines. The driving and driven equipment should be aligned so that a straight edge can beplaced on both coupling flanges at 900 degree intervals and remain parallel to the equipment shafts.Care should be taken when tightening set screws and bolts to insure the proper torque is achieved.
AXIAL ALIGNMENT (See Figure 9)
End float for both the driving and driven shafts is sometimes required for expansion and various otherreasons. End float on most couplings can be limited to any required distance by the use of limited endfloat kits; however, these kits should only be used as recommended by the manufacturer.
After the couplings have been aligned (cold) and the drive run in to obtain normal operating temperature,it shall be shut down and alignment re-checked using the following procedure:
Break all couplings and re-check “hot” alignment. These readings shall not exceed 75 percent of themanufacturer’s maximum allowable tolerances. If they are not within these limits, the procedure shouldbe repeated as often as needed to achieve necessary “hot” readings.
FIGURE 8Coupling parallel alignment
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CONVEYOR INSTALLATION STANDARDS FOR BELT CONVEYORS HANDLING BULK MATERIALSALSO, APPENDIX D, SIXTH EDITION, BELT CONVEYORS FOR BULK MATERIALS
FIGURE 9Coupling parallel alignment
FLEXIBLE COUPLING ALIGNMENT CONTINUED
IDLER ALIGNMENT
The objective in aligning idlers is to achieve settings which are square and in line to the conveyorcenterline and parallel to each other, as shown in Figure 3.
Idlers shall be set from a previously squared and leveled terminal pulley (preferably the discharge pulley,although this is not essential). The suggested method is to use laser alignment techniques to establish adatum line. Alternately, use a tight wire on the conveyor centerline, or offset to it, stretched to form atrue centerline reference. This line should be at least 100 feet long and referenced to the squared startingpulley.
Idlers shall be placed at design spacing and square to the tight wire. After a span of about 50 feet hasbeen filled with idlers, the 100-foot line shall be relocated so that there is a 50-foot overlap on the firstposition. Repositioning of the laser or tight wire should continue until the entire conveyor length is filledwith idlers.
BELT ALIGNMENT
Belt training is usually minimized if:
· Conveyor has been installed straight and level with tolerances stated herein· All pulleys and idlers are square with the conveyor centerline· Belt splices are correct and square· There are no defects in the conveyor belting· All idler rolls turn freely
However, all these conditions are rarely present concurrently, and some training of the belt is usuallyrequired.
NOTE:Belt training should be supervised by one person to insure consistency in adjustments.
Training the belt is a process of adjusting idlers and the method of loading in a manner that will correctany tendency of the belt to run off to one side or the other.
When the belt continues to run off consistently over a fixed length of conveyor, the cause is probably inthe alignment or leveling of the conveyor structures, idlers, or pulleys in that area.
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CONVEYOR INSTALLATION STANDARDS FOR BELT CONVEYORS HANDLING BULK MATERIALSALSO, APPENDIX D, SIXTH EDITION, BELT CONVEYORS FOR BULK MATERIALS
If one or more segments of the belt run off at all points along the conveyor, the cause is more likely thebelt itself, a splice, or the method of loading. When a belt is loaded off center, the lightly loaded edgewill rise on the inclined idler roll that it contacts.
All pulleys should be level and at 90 degrees to the centerline of the conveyor. They should be main-tained this way and never shifted to train the belt.
Training the belt with the troughing idlers is accomplished by shifting the idler axis with respect to thepath of the belt, commonly known as knocking idlers. This method is effective when the entire belt runsto one side along a fixed length of the conveyor. The belt can be centered by knocking ahead (in thedirection of belt travel) the end of the idler to which the belt runs (See Figure 10).
Shifting idlers in this manner should be spread over a length of conveyor preceding the region of trouble.In no event shall any idler be shifted more than 1/4” inch in any direction from its squared position.
NOTECompensation by idler knocking may have adverse effects on reversible belts; therefore, avoidknocking on reversible belts. Instead, use extreme care in initial alignment.
A belt might be made to run straight with half the idlers knocked one way and half the other, but thiswould increase rolling friction between the belt and idlers. For this reason, all idlers must be initiallysquared with the path of the belt in accordance with the Idler Alignment section of this standard, andminimum shifting should be used for training. If the belt is over-corrected by shifting idlers, it should berestored by moving the knocked idlers, not by shifting additional idlers in the other direction.
BELT ALIGNMENT CONTINUED
Figure 10Correcting belt alignment
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CONVEYOR INSTALLATION STANDARDS FOR BELT CONVEYORS HANDLING BULK MATERIALSALSO, APPENDIX D, SIXTH EDITION, BELT CONVEYORS FOR BULK MATERIALS
BELT ALIGNMENT CONTINUED
EMPTY RUN-IN
The conveyor belt should first be aligned (trained) without material load. Most alignment problems, withthe exception of off-center loading, will be detected during this empty run-in period.
After ensuring that all elements have been aligned true as stipulated in the Idler Alignment section of thisstandard, the belt should be slowly inched along to provide indication of where corrections of the typesdescribed may be required. The first corrections must be those at points where the belt is in danger ofbeing damaged. Once the belt is clear of all danger points, a sequence of training operations can befollowed.
The best procedure to use in the training sequence is to start with the return run and work toward the tailpulley. This ensures early centering of the belt on the tail pulley so that it can be centrally loaded. Normallythe belt can be trained properly onto the tail pulley by manipulation of the return idlers.
With the empty belt trained satisfactorily, good operation with load is usually assured. Disturbances thatappear with load are then usually due to off-center loading or to accumulation of material on snub pulleysand return idlers.
If all corrective measures have been applied, and a particular section of belt continues to run to one sidealong the entire conveyor length, it can be concluded that the belt may be cambered at that point or mayhave a splice that is not properly squared. The only corrective measure for a non-squared splice is to re-splice. On the other hand, slight camber in a belt may remove itself after an adequate run-in period underload.
FULL LOAD RUN-IN
A belt may be considered properly aligned if after eight hours of continuous operation under full designload, the belt edges remain within the width of the pulley face. Also, when extra wide face pulleys areused, a further criterion that the belt runs within the confines of the normal troughing, or return, idlershould be followed.
NOTE:Disc return idlers shall be exempt from the above as the standard roll faces supplied are approximatelyequal to the belt width. In this case, the belt shall be made to track within 1-1/2” inches of the conveyorcenterline. Idler brackets shall not restrict this movement.
To obtain the above alignment under load, it will be necessary to ensure that the load is centered and thatall belt scrapers, plows, and skirt seals exert uniform pressure on the belt. Minor adjustments can be madeto these devices to improve tracking.
Carrying and return training idlers should be considered in correcting belt alignment problems beforerejecting the belting or splice.
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CONVEYOR INSTALLATION STANDARDS FOR BELT CONVEYORS HANDLING BULK MATERIALSALSO, APPENDIX D, SIXTH EDITION, BELT CONVEYORS FOR BULK MATERIALS
HELPFUL HINTS:
· One person should be responsible for training belts. This person should supervise all adjust-ments.
· Periodically check the conveyor to be sure it is level. This requirement is apparent if the conveyorbecomes misaligned with no apparent change in loading.
· After the belt is run in, an electrician should take readings on voltage, amperes, or wattage. Thisinformation can be used for future comparison and a quick trouble check. (Higher readings in thefuture may indicate excessive drag due to belt misalignment or frozen belt idler rolls.)
· Do not overtrain the belt. Overtraining will result in increased belt cover wear and increased powerconsumption.
SKIRTBOARD ADJUSTMENT
Skirtboards are an important element of a well designed belt conveyor. They help centralize and shape theload while minimizing spillage over the belt edges and helping to contain dust.
The steel plates that form the skirting (and any chute lining) should be installed high enough to avoid therisk of contact with the belt, yet low enough to protect the rubber or urethane sealing strips from excessiveload pressure and material wear. The cross-sectional area of the chute should be checked carefully tomake certain that the skirting and liner do not interfere with flow. It is critical that these steel plates beinstalled as a smooth, seamless layer that opens in the direction of belt travel, to minimize materialentrapment and the risk of belt damage. Typical dimensions for clearance above the belt start at 3/8 to 1/2 inch above the belt at the tail and open to 3/4 to 1 inch at the exit of the load zone.
Affixed to the bottom of the steel is the skirtboard sealing system, which provides a light, flexible contactwith the conveyor belt. This low sealing pressure will minimize friction while retaining all material withinits boundaries. Excessive pressure will burn grooves in the belt rubber cover and, therefore, must beavoided. Excessive adjustment or downward pressure of the skirtboard seal can lead to accelerated wearof the sealing strip, and/or belt.
The maintenance of a flat and stable belt line in the loading zone is a key to effective sealing. Efforts takento avoid fluctuations in the belt line, including closely spaced idlers, belt support cradles, and spiral-wrapping of wing pulleys have generally proven helpful in controlling fugitive material.
IDLER LUBRICATION
Modern conveyor idlers have evolved through better bearings, improved lubricants, and more effectiveseals. Likewise, the lubrication requirements have changed to accommodate current designs. The followingconsiderations should be reviewed when establishing a lubrication program tailored to a particularinstallation:
BELT ALIGNMENT CONTINUED
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CONVEYOR INSTALLATION STANDARDS FOR BELT CONVEYORS HANDLING BULK MATERIALSALSO, APPENDIX D, SIXTH EDITION, BELT CONVEYORS FOR BULK MATERIALS
MAUNUFACTURER’S RECOMMENDATION
The manufacturer’s data can provide a solid basis for designing the lubrication program.
TYPE OF LUBRICANT
The proper lubricant will be heavily influenced by operating conditions, the operating environment, andthe quality of maintenance program desired. Operating conditions such as operating speed, idler loading,type and size of material being handled, and number of operating hours per year should be considered.
The operating environment is one of the greatest contributors in determining the lubrication program.Temperature, dust, material abrasiveness, washdown techniques, and washdown frequency all affect thelubrication that flushes contaminants from the bearings. Special synthetic lubricants are available for subzerooperating temperatures.
IDLER CONSTRUCTION
The type and efficiency of the seals directly reflect on the lubrication schedule. Following are severalrecommendations that will contribute to establishing a successful lubrication program:
· Remove several idlers from service every six months, disassemble them, and inspect to determineif adequate lubrication has been attained, if migratory contamination and wear have occurred, or ifpressure relief plugs are fouled. If these idlers demonstrate that adequate lubrication has been attained,they could be put back into service and the conveyor operated as normal. If contamination was foundin this sampling, all idlers on the conveyor should be lubricated. Also, fouling of pressure relief plugsin sampling should encourage cleaning of all plugs.
· Thoroughly clean all grease fittings prior to lubricating the idlers to eliminate the possibility ofcontamination introduced during maintenance.
· Establish a good maintenance recordkeeping system. Record the date on which samples weretaken and the condition of the samples taken and verify trends that may be occurring within thesystem. Also record idler failures, including location, to establish system trends and effectiveness ofthe lubrication program. The establishment of a formal lubrication program as described above willincrease the likelihood of many years of successful, trouble-free operation.
SAFETY
ADJUSTMENTS
Conveyors, by design, often have significant potential sources of stored energy. Take ups and inclined (ordeclined) belts loaded with bulk material are two common hazards. It is important that ANSI lockoutprocedures be followed when making adjustments to bring conveyor machinery into tolerance (ref: ASMEB15.1), B20.1, and ANSI Z244.1).
Adjusting rotating or moving components should be avoided. Only trained and authorized personnel,who are aware of the hazards, should be allowed to make such adjustments.
IDLER LUBRICATION CONTINUED
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CONVEYOR INSTALLATION STANDARDS FOR BELT CONVEYORS HANDLING BULK MATERIALSALSO, APPENDIX D, SIXTH EDITION, BELT CONVEYORS FOR BULK MATERIALS
SAFETY LABELS
CEMA Safety Labels and Placement Guidelines were developed by the CEMA Safety Committee to provide,for members and non-members, consensus advice for the selection and application of safety labels for useon conveyors and related material handling equipment to assist in accident prevention.
Prior to operating the conveyor, or any of the associated accessories or equipment, all safety markings,guards, and warnings must be in place in accordance with governmental regulations and site specificrequirments.
Should any of the safety labels supplied by the equipment manufacturer become unreadable for anyreason, the equipment user is then responsible for the replacement and location of these safety labels.
Replacement labels can be obtained from your equipment supplier or CEMA.
CEMA Label Placement Guideline BH-1 is intended for bulk material handling conveyors. A copy of it isappended to this document - See next page.
To download a color copy of BH-1 go to the CEMA Web Site at http://www.cemanet.org/safety/guidelines.html.
The Entire CEMA Safety Label Program is detailed in CEMA Brochure 201 - Safety Label Brochure which isavailable from CEMA.
SAFETY CONTINUED
CEMA Safety Labels Placement Guidelines
Product: Bulk Handling EquipmentEquipment:
BH -1
Belt Conveyors
"D"
General warning to personnel that aconveyor’s moving parts, which operateunguarded by necessity of function, i.e.belts, rollers, terminal pulleys, etc., createhazards to be avoided; in particular,conveyors which stop and start byautomatic control near operator workstations would use this label.
CHR930002
Equipment startsautomatically -can cause severeinjury
KEEP AWAY
LOCATE AT ENTRANCE TO CONVEYORWALKWAY
To be placed on removable guards to warnthat operation of the machinery with guardsremoved would expose chains, belts,gears, shafts, pulleys, couplings, etc. whichcreate hazards
CHR930001
Exposed movingparts can causesevere injury
LOCK OUT POWERbefore removingguard
"A" “B”
To be located on conveyors where thereare exposed moving parts which must beunguarded to facilitate function, i.e. rollers,pulleys, shafts, chains, etc.
CHR930005
Moving equipmentcan cause severeinjury
KEEP AWAY
LOCATE ON INSPECTION DOOR (S)
To be placed on removableguards to warn thatoperation of the machinerywith guards removedwould expose chains,belts, gears, shafts,pul leys, coupl ings, etc.which create hazards.
CVS950020
Exposed movingparts can causesevere injury
LOCK OUT POWERbefore removingguard
"C"
To be placed at entrances to enclosed areaswhich would expose personnel tooperational or environmental hazardswhich should only be entered by trainedand authorized personnel under specificconditions; Examples, lifting conveyors,transfer car aisleways, confinedspaces, etc.
“D”CHR930006
Do not enter
Hazardous area
Authorized personnelonly
“F”
"B"
"F"
"A"
"E"
"D" "C""D" "C""E"
SPACE UP TO A MAXIMUM OF50 FT CENTERS ( WALKWAY SIDES)
CHR930004
Climbing, sitting,walking or riding onconveyor at any timewill cause severeinjury or death
KEEP OFF
To be placed up to a maximum of 50’centers along the walkway side.
"E"
CONVEYOR EQUIPMENT MANUFACTURERS ASSOCIATION6724 Lone Oak Blvd.Naples, Floirda 34109
239-514-3441Fax: 239-514-3470
http://www.cemanet.org