FIELD SERVICE MANUAL
Contents
1. Spiral roll idlers can be used for belt travel in one direction only oO Rexnord LE TYPES OF IDLERS cont FIELD SERVICE MANUAL c Rubber disc Used under the same conditions as the spiral idler These idlers can be used for belt travel in either direction Massed end discs are standard Urethane and ceramic disc rolls also available Carrying Belt Training Idlers Troughing or Flat Assist in keeping the belt centered on the conveyor Actuating shoe type is used on belt traveling in either direction Positive type is used on belt traveling in one direction only and is illustrated Ceramic or urethane covered rolls also available Return Belt Training Idlers Used for the same purpose as are Carrying Training Idlers They are of the actuating shoe type belt travel either direction and the positive and inclined pivot types belt travel one direction only The positive arm type is illustrated Ceramic or urethane covered rolls also available Idler Styles ma a Troughing Impact Troughing Training b W ILIAAN Ribbed Covered Return Disc Return Spiral Return Flat Impact Live Shaft Impact Inclined Return Training Rexnord Corporation Idler Division Re 4800 West Mitchell Street P O Box 2022 Milwaukee Wisconsin 53201 414 643 3000 Fax 414 643 2600 CONVEYOR EQUIPMENT Ill i A A www rexnord com e mail ECsales rexnord com MANUFACTURERS ASSOCIATION2. MANUAL REX G SEAL REGREASABLE OR FACTORY SEALED ROTATING PARTS GREASE REGREASABLE IDLERS Better Protection Against Abrasives and Moisture Rex offers a special combination labyrinth and protective outer shield for your operating environment This seal has five hard to get through passages filled with grease to block contaminants from the roller bearings The outer and inner seals are close tolerance injection molded nonmetallic The labyrinth shield seal is particularly excellent for long overland horizontal conveyors because of its low friction torque or for applications where water is present or when frequent washdowns are required 20 ROTATING PARTS GREASE FACTORY SEALED IDLERS Better Protection Against Abrasives and Moisture Rex offers a special combination of labyrinth and protective outer shield for your operating environment This seal has five hard to get through passages filled with grease to block contaminants from the roller bearings The outer and inner seals are close tolerance injection molded nonmetallic The factory sealed idlers feature the same labyrinth shield seal as the regreasable idlers but with an added internal wiping seal to further delay the penetration of contaminants This product will provide excellent service in relatively clean environments or where minimum maintenance can be provided FIELD SERVICE MANUAL Rexnord LLL SECTION V BELT CONVEYOR
3. for the loading skirts use a board as a gage for clearance between the idler roll and the bottom of the steel skirt 10 FIELD SERVICE MANUAL RUBBER SKIRT RE After installation of the conveyor belt install the rubber skirt The rubber should lay on the conveyor belt with a minimum of pressure F FE A Clearance to be adjusted and held when setting steel at skirt plate FIELD SERVICE MANUAL INSTALLATION CHECKLIST The following items should be inspected before initial operation 1 NO gee GUN Head and foot shafts parallel to each other and pulleys in line All bolts properly tightened Idlers secured in line Reducer filled to proper oil level Oil in chain guards S A E 30 to proper level Correct motor rotation Check and remove all tools and any other foreign objects from the belt particularly on the return side where they may get between the terminal pulleys and belt Grease on the belt should be removed immediately as it will deteriorate the belt For Notes 13 14 Rexnord LLL Counterweight installed and gravity take up blocking removed Screw take up pulled back and pulley square 10 11 12 Belt wipers installed and properly adjusted Emergency stop cords and switches installed Bearing stop blocks welded to terminal frame steel or adjusting screws tight up against bearing bases Flop gates operative and in correct position for mater
4. loaded belt will track in the center of the idlers without using training idlers Training idlers are used to compensate for occasional irregular loading the effects of wind and other varying conditions TROUGHING TRAINING IDLERS POSITIVE TYPE Troughed training idlers are installed along the conveyor length as required but not closer than fifty feet from a pulley Positive type can be used on belts traveling in one direction only TROUGHING TRAINING IDLERS ACTUATING SHOE TYPE Actuating shoe type can be used on reversing belts and on belts with traveling trippers or stackers 14 FIELD SERVICE MANUAL RETURN TRAINING IDLERS POSITIVE TYPE Return training idlers are installed along the conveyor length as required but not closer than fifty feet from a pulley Positive arm and inclined pivot type can be used on belts traveling in one direction only RETURN TRAINING IDLERS ACTUATING SHOE TYPE Actuating shoe type can be used on reversing belts RETURN TRAINING IDLERS INCLINED PIVOT TYPE Inclined pivot type can be used on belts traveling in one direction only Rexnord FIELD SERVICE MANUAL mT SIDE GUIDE IDLERS Side guide idlers do not train a belt They are used to prevent a belt from running off the pulleys and to prevent the belt from damage caused by the conveyor structure and other objects They should be installed so that th
5. only require more splicing tension than those pulled in both directions 2 Slope belts spliced at the top of a slope require more splicing tension than those spliced at the bottom 3 Slope belts having an anti rollback which cannot be released must be tensioned by pulling in the direction of belt travel only Use a series of clamp off devices to take out belt slack 4 Check the belt frequently during tensioning to make sure that the belt is free and not binding anywhere Short belts may easily have too much tension applied and thus have a harmful effect on the pulley bearings as well as the belt On a conveyor with a gravity take up the splice should be made near the take up It is recommended that the belting manufacturers detailed instructions are followed when making the actual splice SPLICING AREA PULL HERE E AAA a PLYWOOD Rexnord LE LS Mechanical Fasteners Each box of mechanical fasteners is complete with a set of instructions and a list of tools required to splice the belt Belt Scrapers A scraper is located at the head end of a belt conveyor to remove material from the belt and into a receiving chute A counterweight or spring keeps the scraper blade against the belt Proper field adjustment is required periodically RUBBER SKIRTS LOADING AREAS APPROXIMATELY 3 4 PLUS THICKNESS OF CONVEYOR BELT STEEL SKIRT When setting the steel
6. runs off center is usually caused by improper loading Chutes should distribute the load evenly and on the center of the belt Loading Start with a light load and gradually work up the load that the conveyor was designed to handle Check chutes to see that the material is being directed onto the center of the belt Rexnord LLL Off center loading is harmful to the belt idlers and shafting An off center load will affect belt alignment in that the belt will run off center A centered load will maintain belt alignment See illustration below The loading point of a belt conveyor is the critical area Here the conveyor is subjected to maximum abrasion and impact The desired condition is to load the material at the same speed and direction of travel as the belt with a minimum amount of impact and on the center of the belt The skirts must be adjusted to prevent spillage and to keep the load centered on the belt The maximum recommended distance between skirtboards is two thirds the width of a troughed belt It is desirable to reduce this spacing to one half the width of the troughed belt when conveying free flowing materials The skirt length should be designed to prevent side spillage until the material is at rest on the belt If the material is still tumbling as it passes the skirt end the skirts should be lengthened 13 Rexnord LET TYPES AND ADJUSTMENT OF TRAINING IDLERS A properly aligned and centrally
7. slip on starting 22110 E Excessive belt stretch Belt breaks at or behind 2 23 13 22 20 fasteners fasteners tear ooe 15 22 21 16 15 16 21 10 cracks ruptures gouges Belt hardens or cracks Covers become checked or 8 brittle Longitudinal grooving or cracking of top cover Longitudinal grooving or BoE of bottom cover Fabric decay carcass soft spots in belt separation 21 Rexnord ELE 10 11 12 FIELD SERVICE MANUAL CAUSES AND THEIR CURES Belt bowed Avoid telescoping belt rolls or storing them in damp locations A new belt should be straighten out when broken in or it must be replaced Belt improperly spliced or wrong fasteners Use correct fasteners Retighten after running for a short while If improperly spliced remove belt splice and make a new splice Set up regular inspection schedule Belt speed too fast Reduce belt speed Belt strained on one side Allow time for new belt to break in If belt does not break in properly or is not new remove strained section and splice in a new piece Breaker strip missing or inadequate When service is lost install belt with proper breaker strip Counterweight too heavy Recalculate weight required and adjust counterweight accordingly If using screw take ups reduce take up tension to point of slip then tighten slowly Counterweight too light Recalculate weight req
8. that it is operating properly If a belt cleaner has not been installed it is recommended that one is placed in operation as soon as possible Excessive build up on idler rolls will cause damage to the belt Shut down the conveyor locking out the power switch and clean up or repair immediately Rex spiral or rubber disc return idlers are designed to keep material build up on the rolls to a minimum Check all training idlers to see that they are pivoting freely KEEP CLEAN FIELD SERVICE MANUAL Clean up any spilled material that might restrict the idler from pivoting freely and free any frozen pivots Check to be sure all lubrication fittings are in good condition Replace where needed CONVEYOR IDLER MAINTENANCE Inspection and Maintenance Ascheduled maintenance program followed faithfully by trained people can usually help avoid costly interruptions in production and repairs to equipment Many operators make a cursory check at least once a day to find obvious problems Amore comprehensive inspection is made at period intervals Inspection should include checking the following 1 Inspect the belt for breaks or cuts or for indications that the belt edge is rubbing 2 Make sure center of the belt is running on the center of the idler 3 Loading areas should be checked to see that material is being loaded evenly and on the center of the belt 4 Rubber skirts on chutes and skirt plates are adjusted to prevent sp
9. Bulletin No 6000 Copyright Rexnord Corporation 2002 11 05 500 RAM Printed in the U S A
10. HINERY ERECTION The basic working points that were used during the steel erection should now be transferred to the conveyor frame to assist in the proper location and alignment of the pulleys and idlers etc When located correctly the piano wire affords a working centerline from which measurements for alignment can be made The bearing pads should be leveled before installation of the pulley shaft assemblies If shims are necessary they should be large enough to take the entire machined surface of the bearing base Before installing any pulley shaft assemblies check the general arrangement drawing for size and mark numbers After securing the head and tail pulley shaft assemblies perpendicular to the line of belt travel parallel with each other and level it is good practice to set stop blocks against the bearings and weld these blocks to the steel The holes in the bearing base are slotted and the stop blocks will prevent the bearings from shifting Install bend pulleys and the gravity take up pulley as shown on the general arrangement drawing Automatic Take Up Be sure that the pulley turns freely and that the take up frame slides easily to compensate for variations in belt tension Use recommended amount of counterweight and adjust if necessary FIELD SERVICE MANUAL Manual Take Up Adjust the take up so that the belt tension is sufficient to insure that the loaded belt will operate over the terminal pulleys with
11. Lithium soap base Mineral oil Worked penetration 265 295 77 F Operating range of 225 F to 10 F Bleed rate 3 maximum It is recommended that an equivalent grease be used When using any other type of grease it is imperative that it be compatible with the original grease ae ON When lubricating idlers the use of high pressure equipment is not only unnecessary but is actually undesirable unless used with great care High pressure may cause damage to bearings and seals It is recommended that a VOLUME TYPE GREASE GUN BE USED one that delivers an ounce of grease per seven to ten strokes of the lever 17 Rexnord LE All fittings should be wiped clean before lubricating so as not to introduce dirt IDLER LUBRICATION TECHNIQUES Rex idlers should be lubricated with a high volume low pressure gun to insure purging of all seals This type of grease gun delivers an ounce of grease every 7 to 10 pumps High pressure low volume guns should not be used because they do not deliver enough volume of grease per stroke to purge all seals The greasing system relies on a generous volume of grease per stroke to create the pressure distribution necessary to purge all seals An ounce of grease is normally required to purge a CEMA B or C idler 1 5 oz for CEMA E A good grade of NLGI 2 grease with low bleed characteristics should be used Mobil Oil Company grease Mobilux EP2 or equal is recommended REXNORD PATENTED TH
12. RU GREASING SYSTEM Most customers recognize the need to lubricate idler bearings in order to extend idler life Relubricating flushes out contaminants especially through the labyrinth clearance type seals The most positive way to assure that grease reaches each bearing is to have an individual fitting on each bearing But vulnerability to damage added cost and inconvenience of multiple grease points make this impractical FIELD SERVICE MANUAL One point thru greasing is now available from most idler manufacturers This system is essentially a channel through the center of the idler with outlets to the six bearings Fig 1 A grease fitting at one or both ends of the idler is used to introduce fresh grease A short tube is generally used to transfer grease from roll to roll One point thru greasing is successful only if the system can meter grease equally to all six bearings a proven feature of Rex idlers Radial hole size becomes critical when using open purge type seals A large diameter radial hole allows most of the grease to be released through the first two labyrinth seals Pressure at the third fourth fifth and sixth seals is practically zero as shown in Figure 3 A small diameter radial hole restricts grease flow and produces a more uniform pressure Figure 5 Figure 2 is a schematic diagram of a typical one point thru grease system A pressure distance diagram Fig 3 shows a momentary high pressure at be
13. Rex Idlers Belt Conveyor Components Whisperol Rollers and Spray Nozzles SERVICE MANUAL Rexnord HLL IMPORTANT Safety Instructions Compliance with safety standards including OSHA and other Federal State local codes or regulations is the responsibility of the user of the conveyor installation Placement of guards and other safety equipment in accordance with safety standards is dependent upon the area and use to which the system is put A safety study should be made of the conveyor application and guards should be installed wherever appropriate Safety Standard For Conveyors And Related Equipment ANSI B20 1 is a guide for safe construction installation operation and maintenance of conveyors and related equipment FIELD SERVICE MANUAL Rexnord SECTION Vi WUE DESCRIPTION PAGE BELT CONVEYOR SAFETY INSTRUCTIONS PREFACE GENERAL BELT CONVEYOR INFORMATION Typical belt conveyor layout 2 00000 cee nce eee eee ee eee 2 Typical belt conveyor schematic 00000 eee 3 BELT CONVEYOR INSTALLATION INFORMATION Steel erection accra Soe enn into Ser Seek aaah secon case den dec wt dtc a 4 Machinery erection cra e ea haw See eee ed le a ae 6 Idler installation 0 0 ee eee ee eee 6 Belt installation 2 0 0 ee ee eee eee 7 Skirts loading areas 0 0 0 teens 10 Installation checklist 2 0 0 ee eee 11 BELT CONVEYOR OPERATION INFORMATION Conveyor sta
14. TROUBLE SHOOTING GUIDE Any belt conveyor installation can be subject to a wide variety of difficulties which may become costly in terms of replacement and plant downtime unless the problem is quickly diagnosed and corrected This guide is intended to point out the majority of belt conveyor problems and set forth their probably causes and cures Locate your specific problem in the complaint column below and note the numbers to the right They represent the most likely causes for the problem in order of probable occurrence and how to correct them The list on the next page details the causes and cures by number The cures will correct the majority of belt conveyor troubles However some remedies require lengthy procedures which should be referred to your Rexnord representatives COMMON BELT CONVEYOR COMPLAINTS CAUSE In Order of Probable Occurrence COMPLAINT Belt runs off at tail pulley CAUSE In Order of Probable Occurrence COMPLAINT Excessive wear including rips gouges ruptures and tears 12 25 17 21 8 5 Entire belt runs off at all points of the line One belt section runs off at l 2 11 1 all points of the line Belt runs off at head pulley 7 15 14 17 21 26 17 15 21 4 16 Excessive bottom cover wear Excessive edge wear broken edges Cover swells in spots or streaks 21 14 5 19 20 22 Belt runs to one side throughout entire length at specific idlers Belt
15. aring 1 and some residual pressure at bearings 2 and 3 but almost no pressure from bearing 4 on Without a pressure differential between the inside of the shaft and the outside grease will not flow through the bearing cavity Pressure can be increased throughout the system by blocking off all exists Figure 4 shows what happens to a hypothetical system with all outlets blocked Rexnord FIELD SERVICE MANUAL mT BEARING 1 4 GREASE Figure 2 PRESSURE IN SHAFT LENGTH LARGE RADIAL HOLE FAR END PLUGGED Figure 3 PRESSURE IN SHAFT LENGTH NO RADIAL HOLES FAR END PLUGGED Figure 3 aoe PRESSURE IN SHAFT LENGTH SMALLRADIAL HOLE FAR END PLUGGED Figure 3 Figure 5 diagrams pressure distance in a system where small diameter radial holes meter grease to each bearing In the system the radial holes are small enough to restrict grease flow into the bearing cavities This causes a momentary high pressure throughout the system This high pressure is relatively uniform from end to end and release of grease through the small radial grease holes is also relatively uniform The large diameter reinforced rubber connecting tubes tend to give a little acting as surge tanks to smooth out the pressure peaks and assure flow into the six bearings The tube can be seen in Figure 6 Rexnord ELE FIELD SERVICE
16. art at an anchored or lower end of the conveyor Examination of the general arrangement drawings will show the relationship between working points and mark numbers The mark number sequence and location must be followed during field erection The working points shown represent the only tie between existing and proposed steelwork buildings and equipment These points are critical and must be located with accuracy to insure correct installation of conveyors Accurate alignment is necessary to insure a true running belt All steelwork must be square level and in line Several sections must be bolted together on the ground before lifting taking care that the maximum allowable spans between supporting bents is not exceeded Proper clearances must be maintained All shafting must turn freely with bolts in place FIELD SERVICE MANUAL The frames trusses etc must be installed correctly Temporary bracing is to be used wherever necessary to handle loads which the structure may be subjected during erection Standard construction of fabricated steel allows for minor variation in lengths and hole locations Minor misfits are considered a normal part of erection work The accumulation of tolerances in foundations grades setting of anchor bolts etc make it necessary to use drift pins reamers gas cutting and welding equipment Dimensional tolerances must be compensated for in fit up When new truss sections or conveyor units are ti
17. e Improve maintenance Don t overlubricate Idlers or pulleys out of square with center line of conveyor Realign Install limit switches for greater safety Idlers improperly placed Relocate idlers or insert additional idlers spaced to support belt Improper loading spillage Feed should be in direction of belt travel and at belt speed centered on the belt Control flow with feeders chutes and skirtboards Improper storage or handling Refer to your Rexnord representative for storage and handling tips Insufficient traction between belt and pulley Increase wrap with snub pulleys Lag drive pulley In wet conditions use grooved lagging Install correct cleaning devices on belt Install centrifugal switch for safety Material between belt and pulley Use skirtboards properly Remove accumulation Improve maintenance Material build up Remove accumulation Install cleaning devices scrapers and inverted V decking Improve housekeeping Pulley lagging worn Replace worn pulley lagging Use grooved lagging for wet conditions Pulleys too small Use larger diameter pulleys Radius of convex vertical curve too small Increase radius by vertical realignment of idlers to prevent excessive edge tension Relative loading velocity too high or too low Adjust chutes or correct belt speed Consider use of impact idlers Side loading Load in direction of belt travel in center
18. ed into existing units it is expected that a major amount of fit up may be required The accumulated tolerances are already built into the existing equipment making the job of tie in and alignment a matter of detail fit up No welding should be done until the structure has been fit up and properly aligned SET IDLER PERPINDICULAR TO CENTER LINE 2 Locate Rexnord LLL The conveyor stringers and decking should be set up checked for centers and leveled before being permanently secured to supporting members Before proceeding with the steel erection a centerline for the conveyor should be established This is done by stretching piano wire the entire length of the frame or portions of the frame on long conveyors Anchor the wire at convenient points a suggested method is given below 1 Secure an eyebolt to a piece of steel the eyebolt on the approximate centerline of the conveyor Remember to keep the eyebolt above the center roll of the idlers Fasten eyebolt bracket to structure Install a similar eyebolt bracket at the opposite end or at a convenient intermediate point if the frame has a bend slope or reflex curve 5 String the piano wire adjust on centerline pull taut and secure POSITION WIRE 1 TO 2 ABOVE TOP OF CENTER ROLL SET IDLER LEVEL ACROSS WIDTH OF CONVEYOR AND ON CENTERLINE OF CONVEYOR FRAME Rexnord LLL MAC
19. ey do not touch PIVOTCAP the belt edge when it is running normally If the belt runs against side guide idler rolls continuously belt damage can occur even if the rolls rotate freely TRAINING IDLER PIVOT ADJUSTMENT do Adjustment of the pivoting action of training idlers Om 1904s can be made by loosening the two bolts and moving BOLTS th angel in or out to change the amount of allowable movement The pivot stop is set at the factory for normal operation ADJUSTING ANGLE CENTRAL PIVOT FOR TRAINING IDLERS General Information Heavy cast housing and cap Bearing cavity pregreased and sealed for long bearing life Opposing tapered roller bearings to handle radial and thrust OPPOSING HEAVY DUTY HUSKY TAPERED ROLLER BEARINGS a ae LARGE GREASE RESERVOIR pa BEARING RETAINERS LOCKED IN PLACE SEALING CAP 15 Rexnord LLL FIELD SERVICE MANUAL SECTION IV CONVEYOR IDLER MAINTENANCE AND LUBRICATION INFORMATION CONVEYOR IDLER INSPECTION Regularly scheduled inspections of conveyor systems is the best preventive maintenance possible Problem areas can be detected and corrected before damage occurs to the belt or equipment A check of the loading areas is the best place to start Loading chutes should be delivering material to the belt evenly and centered on the belt Uneven or off centered loading i
20. f the slack from the belt On conveyors with long centers it may be necessary to take two hitches while stringing the belt one to remove slack on the return side then a second hitch on the carrying side It is important to remove as much slack as possible while stringing the belt The belt will stretch during its initial operation which points out the importance of stringing a tight belt initially Handling of Belts Conveyor belts are usually packaged in cylindrical crates which may be rolled from place to place All crates and rolls are marked with an arrow showing the direction in which the crate or roll should be rotated When hoisting the belt a bar is passed through the hole in the center of the roll Chains or cables looped around the bar should have a spreader above the roll to avoid damage to the belt edges Never store the belt on its edges The belt should always be suspended on a tube or bar if it is to be stored for any length of time Stringing and Splicing of Belt The roll of belting should be brought to a location which will allow ease of stringing Mount the roll on a shaft and suitable structure for unrolling and threading on to the conveyor See sketch next page NOTE A temporary flat idler roll should be installed at the bend point of the belt Conveyor belting is normally rolled at the factory with the carrying side out Consequently the belt must lead off the top of the roll if it is being fed
21. ial flow Rubber skirting at loading points installed and adjusted 11 Rexnord ELE FIELD SERVICE MANUAL SECTION lll BELT CONVEYOR OPERATION INFORMATION CONVEYOR START UP Before actual start up of a conveyor system electrical controls should be checked to insure that the entire system can be stopped quickly in case of emergency During initial start up the conveyor should be jogged on and off until the belt has made several complete revolutions During this period make a thorough check of all equipment to determine proper adjustment and function BELT TRAINING Belt training is a process of adjusting idlers and loading conditions in a manner which will correct any tendency of the belt to run off DO NOT ATTEMPT to train the belt by unequal adjustment of the screw take ups A misaligned conveyor will cause the belt to run off to one side The belt will tend to creep to the side that makes first contact with the idler roll This condition can usually be corrected by adjusting a few idlers to change th contact points The return side should be adjusted first starting at the head end Note the run off point and adjust a few of the preceding idlers The adjustments are made by shifting the idlers so that the belt contacts the roll opposite the run off See sketch A slight adjustment on a number of idlers is recommended Repeat this procedure at other points along the belt if necessary until the return side is runn
22. illage 5 Belt cleaners are properly adjusted and working 6 Rex idlers are designed to be self cleaning Accumulation of material must not be allowed to prevent idler rolls from rotating or prevent training idlers from pivoting 7 Check to see that all idler rolls are rotating A stalled roll will cause excessive roll shell and belt wear and should be replace CONVEYOR IDLER LUBRICATION All idlers are prelubricated at the factory and are ready for operation All external lubrication lines either furnished by Rexnord or added by the customer should be filled with grease when installed to insure that the idlers will get grease when lubrication cycle is started Under normal conditions relubrication should be every 4000 to 6000 hours until a clean bead of grease appears around the final opening of each seal See sketch The lubrication cycle can be lengthened in applications where operating conditions are clean dry of moderate temperature and slow speed The cycle should be shortened in applications where severe dirt high humidity elevated temperatures high speeds free water prolonged shutdown or Rexnord MEE other extreme conditions are encountered Periodic inspection during the first few years of operations will provide the best determination of required relubrication frequency Rex idlers are greased at the factory with Lithium EP grease with a NLGI 2 consistency having the following characteristics 1
23. ing true The carrying side can then be adjusted by using this same procedure starting at the tail end and proceeding toward the head end 12 Mi ew BELT RUN OFF BEFORE ADJUSTMENT PERPENDICULAR TO BELT LINE ADJUSTMENT BELT TRAVEL AFTER ADJUSTMENT Gp aa Belt training may be improved by tilting the troughing idlers See sketch 2 MAXIMUM gt I DIRECTION OF TRAVEL H WASHER Tilt the idlers forward a maximum of 2 in the direction of belt travel This is done by placing washers under the back of the mounting pads FIELD SERVICE MANUAL Return idlers cannot be tilted however by shifting their axis they can be used to provide a corrective effect This can be done by slightly advancing and raising the alternate ends of the return rolls nearest the tail pulley This can be done for expediency on a temporary basis If this area is a training problem a self aligning return idler should be installed about the 214 or 34 idler from the tail pulley NOTE Shifting or tilting of idlers for belt training can only be used for belts traveling in one direction only This remedy cannot be used for reversing belt conveyors Training Loading Belt Once the belt has been properly trained while running empty the belt must be checked when carrying a full load A properly trained belt will run true under loaded conditions A loaded belt that
24. of conveyor Skirts improperly placed Install skirtboards so that they do not rub against belt adjust Consult your Rexnord representative for additional recommendations or procedures Space limitation prevent us from printing complete information in this guide 22 FIELD SERVICE MANUAL Rexnord LLL SECTION VI IDLER REPLACEMENT PARTS IDENTIFICATION TYPES OF IDLERS Carrying Idlers Troughing or Flat Support the belt in the section of the conveyor that transports the material These idlers may be flat or troughed to shape the belt to prevent spillage and are available in 20 35 and 45 trough angels with equal or unequal roll lengths Ceramic or urethane covered rolls also available Impact Idlers Prevent damage to the belt at the loading point These idlers may be troughing or flat types with grooved molded rubber rolls It is standard practice to use impact idlers at all loading and transfer points when the impact exceed 40 foot pounds Return Idlers Support the empty belt between the discharge point and the tail pulley a Standard Used where materials are not sticky corrosive or abrasive Ceramic or urethane covered rolls also available b Spiral Used where sticky materials adhere to the belt where a corrosive environment is present or abrasive wear is a problem Their unique construction minimizes belt fleet and damage to the return belt due to material build up on the idler rolls
25. onto the carrying idlers If the belt is being fed onto the return idlers it must be lead off the bottom of the roll Rexnord LE LS In some cases such as in mines where head room does not permit maneuvering a roll the belt may have to be pulled off the roll and reefed Extreme care should be exercised to see that the loops have large bends to avoid kinking or placing undue strain on the belt Weight should never be placed on the belt when it is in this position See sketch TEMPORARY FLAT ROLL AT BEND POINT NO WEIGHT TO BE PLACED ON TOP KEEP BENDS LARGE TO PREVENT BREAKING CARCASS FIELD SERVICE MANUAL Before stringing the belt the erector should make certain that the thickets rubber cover of the belt will be on the top or load carrying side Holes or notches should not be cut through the belt for attaching a pull rope A clamping device should be used to distribute the force across the belt See sketch ie 1 4 PLATE ABOUT 1 2 BELT WIDTH D WELD EYE TO PLATE i BACK UP PLATE Since the clamp must pass through narrow opening it is usually made of 1 4 plate approximately one half of the belt width The bolts are placed through both plates at 6 intervals and 2 from the belt end A rope or cable is attached to this clamp by means of an eye welded to the plate The rope or cable is then threaded over the conveyor and attached to some s
26. out slipping Excessive take up on the belt will cause undue strain on shafting bearings and belt splicing It will also tend to keep the belt from troughing properly IDLER INSTALLATION Storage and Preparation If idlers and other equipment arrive on the job site in advance of their installation some protective measures should be taken against exposure to the weather and other adverse conditions Rex idlers are normally shipped on skids or pallets These should be stored so that water will not collect around them and should be covered if stored outdoors Before installation idlers should be inspected and cleaned of any foreign matter that may have accumulated during storage or transit Foreign matter on idler rolls can cause damage to the belt Troughing Idlers When installing a conveyor system troughing or carrying idlers should be installed first Starting at the tail end of the conveyor the first standard troughing idler should be located an approximate distance from the centerline of the tail pulley equal to one belt width for 20 troughed idlers 11 2 times belt width for 35 troughed idlers and twice the belt width for 45 troughed idlers It is good practice to use a 20 troughing idler as a transition idler for the first and last idler when using 35 troughing idlers and both a 20 and a 35 troughing idler when using 45 troughing idlers Place idlers in position by sliding them in the direction of belt t
27. ravel firmly against the mounting bolts and lightly tighten Final alignment requires that the center of all idlers are in a straight line perpendicular to the line of belt travel properly spaced and level When alignment is complete bolt the idlers securely in place FIELD SERVICE MANUAL Return Idlers After the carrying idlers have been set in place the return idles should be installed The return idlers must be installed perpendicular to the conveyor centerline and level Leave the training idlers out until the belt has been properly trained BELT TRAVEL Single return idlers are used where sticky materials adhere to the belt where a corrosive environment is present or abrasive wear is a problem Their unique construction minimizes belt fleet and damage to the return belt due to material build up on the idler rolls Spiral return idlers can be used for belt travel in one direction only Install only as instructed on installation instruction tag Rexnord LLL BELT INSTALLATION Position of Take Up The screw take up should be set about 3 from the full forward position toward head end of conveyor The gravity take up frame should be positioned approximately one foot below the upper stop on the take up guides The dimension should be measured from the bottom of the upper stop of the take up frame Installation of Belt On conveyors with short centers 200 300 feet there should be no problem in removing all o
28. rs and Equipment Manufacturers utilize this layout as a basis for foundation and conveyor designs In addition profile drawings must be used to show elevations of pits tunnels crusher house and transfer towers and related chutes 2 The accuracy with which these base lines and grades are set has a direct bearing on the ease of erection of structural supports and conveyor runs Indicates the key dimensions from the conveyor centerlines and working points Rexnord FIELD SERVICE MANUAL mT THE BELT CONVEYOR The layout shown below illustrates a basic belt conveyor Unlimited variations of elevation loading discharge idlers their spacing pulleys and accessories are possible Transition Steel A Idlers Carrying Idlers Carrying Training Idler Carrying gt a Impact oe ee A 9 Idlers Y AMAS Hopper Spiral or Rubber Disc Return Idlers Pulleys Gravity Return Take up Training optional Idler Manual Return Take up Idlers IDLER FUNCTIONS IMPACT Designed to absorb impact and protect the belt from sharp edged material Normally spaced as close together as possible CARRYING Support the belt and provide a trough to contain the material Normal spacing 3 to 5 feet TRAINING Used to compensate for irregular loading wind and other varying conditions Normally spaced no closer than 50 feet to the head or tail pulley TRANSITION These idlers ease the belt from a troughed configuration
29. rt up uz oiga tens oe ann ii od cette ed eae on eee 12 A Soe ere ai sl ms etek Tatar a eee eG erg ee aban me Sac eae etc a 12 Types of training idlers sic cca dosed ene ccd va dges AA 14 CONVEYOR IDLER MAINTENANCE AND LUBRICATION INFORMATION Idler inspection 0 00 e eee 16 Idler maintenance o 17 Idler lubrication 0 00 17 Idler lubrication techniques 0 0 00s 18 Thru greasing SYSIGIMN si de avec oe ov eww etAehaCeeera Sd dads ha nwd See RGA wierd 18 Idler sgal sece 3 teak Seda ci Poli WEG a PA Oe si a le wood aa ole 20 BELT CONVEYOR TROUBLESHOOTING GUIDE Table of common belt conveyor complaints 0 000 c eee eee 21 GAlses and CUES spare E A N a 22 IDLER REPLACEMENT PARTS IDENTIFICATION Types of IGIGKS senres beneno e He a di aia ha T a ba eee we 23 Rexnord LET FIELD SERVICE MANUAL SECTION GENERAL BELT CONVEYOR INFORMATION TYPICAL BELT CONVEYOR LAYOUT an FOUNDATIONS R R TRACKS oo BELT FEEDER FOR TRACK HOPPER y RECLAIM HOPPER FEEDER RECLAIM HOPPER CRUSHER Z KA HOUSE a CONVEYOR E TRANSFER TOWER A 1 The above layout illustrates a typical belt conveyor arrangement The working points W P and centerlines of the various conveyors are shown The drawings prepared by the Enginee
30. s the greatest cause of problems on any belt conveyor Noticeable vibrations should be located and eliminated as this may loosen mounting bolts and cause the idlers to shift Misalignment problems must be corrected at once Walking the length of the conveyor installation and checking the idler rolls to be sure that they are all turning freely and smoothly with no excessive end play is recommended as part of the periodic inspection Roll failure can in most cases be found before the roll stops rotating Unusual noises are an early indication of roll failure Stalled rolls must be cleared immediately If rotation is retarded by material build up against the roll clear immediately Stalled rolls not only drain energy from the system but also cause excessive roll shell and belt wear and should be replaced First stop the conveyor and lock out the power switch Then remove and replace any rolls not operating properly Faulty rolls can be disassembled and repaired Watch for unusual wear patterns on the idler rolls which can be caused by off centered loading or idler misalignment Check idler alignment and adjust as required remember to retighten mounting bolts If off centered loads occur make corrections to chute work Check for material build up on idler rolls particularly the return rolls as these are in direct contact with the carrying side of the belt 16 If build up occurs check the belt cleaner to be sure
31. to the flat pulley surface reducing stress in the outer belt edges RETURN Simply support the belt on its return journey 10 feet spacing is typical FROBISM SOLVER Since these contact the dirty side of the belt they are normally placed prior to the belt contacting another pulley and could be spiral rubber disc poly roll or urethane coated to resist material build up In areas where abrasive wear is a problem 1 4 roll 3 Rexnord ELE FIELD SERVICE MANUAL SECTION Il BELT CONVEYOR INSTALLATION INFORMATION STEEL ERECTION The concrete base on which the conveyor will be installed must be set accurately The anchor bolts must be positioned exactly as shown on the general arrangement drawing If the location of the anchor bolts is not correct the situation must be remedied If the error is slight it is possible to compensate by elongating the bolt holes in the steel pads However if the error cannot be corrected in this manner the bolts will have to be relocated Any sizeable error in locating the bolts would mean additional trouble later in the erection of the conveyor Tie in points could be missed loading and discharge areas misdirected and interference with existing structures encountered See the example below and particularly note the concrete base for anchor bolts It is apparent that if the base is not located accurately there are many areas which may cause problems as the erection progresses Erection should st
32. uired and adjust counterweight accordingly If using screw take up increase tension Damage by abrasives acid chemicals heat mildew oil Use belt designed for specific condition For abrasive materials working into cuts and between plies make spot repairs with cold patch or with Permanent Repair Patch Seal metal fasteners or replace with vulcanized step splice Enclose conveyor for protection against rain snow and sun Don t overlubricate idlers Differential speed wrong on dual pulleys Make necessary adjustment Drive underbelted Recalculate maximum belt tensions and select correct belt If conveyor is over extended consider using two flight system with transfer point If carcass is not rigid enough for load install belt with with proper flexibility when service is lost Edge worn or broken Repair belt edge Remove badly worn or out of square section and splice in a new piece Excessive impact of material on belt or fasteners Use correctly designed chutes and baffles Make vulcanized splices Install impact idlers Where possible load fines first Where 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 material is trapped under skirts skirtboards to minimum clearance Excessive tension Recalculate and adjust tension Use vulcanized splice within recommended limits Idler rolls not turning Correct or replace stalled rolls Lubricat
33. uitable towing device to pull the belt Installations having a relatively high degree of slope 12 degrees or more must be handled with more precautions against runaway As the belt is fed on the tension at the roll tends to build up due to the weight of the belt on the slope Therefore some method of braking is required Customary practice is to use a belt clamp mounted on the conveyor structure through which the belt is threaded Where the slope is very long additional clamps should be used spaced approximately 1 000 feet apart The final splice should be made at the bottom of the slope where the splicing tension required is lowest Making the final splice at the top is possible but a higher tension will be required FIELD SERVICE MANUAL Tensioning the Belt Once the belt has been pulled onto the conveyor it must be tensioned prior to splicing to avoid initial dissipation of take up travel The tensioning operation takes place at the location where the last splice will be made Clamps are placed on each end of the belt These are made of hard wood and have a Clamping surface as indicated See sketch BELT CLAMP CONTOUR PULL HERE REMOVE SLACK Rexnord LLL Tension is applied by means of come alongs which are hooked on each end of the belt clamps Certain basic statements can be made about splicing tensions 1 Belts which are clamped off on one end and tensioned by pulling in one direction
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