MANAGING CONVEYOR LIFE •WHAT IS A CONVEYOR •TYPES OF CONVEYOR •MAINTENANCE OF CONVEYOR •OPTIMISATION TECHNIQUES Benefits of Conveyor systems •safely transport materials from one level to another, which when done by human labour would be strenuous and expensive. •can be installed almost anywhere, and are much safer than using a forklift or other machine to move materials. •can move loads of all shapes, sizes and weights •variety of options available for running conveying systems, including the hydraulic, mechanical and fully automated systems, which are equipped to fit individual needs. What is a conveyor? A conveyor moves material. A conveyor moves cardboard boxes, wood boxes, metal boxes and plastic boxes. Conveyors Can move materials by gravity or power. A conveyor can do more. It can move boxes UP against gravity . . . DOWN . . . or HORIZONTAL on a moving belt. The belt is moved by electric power. This is called a BELT CONVEYOR. What is a belt conveyor? It is a machine with a moving BELT. The machine is made with these parts: A Bed This is a conveyor bed. It comes in many sizes-many lengths-many widths. A Pulley A pulley is like an iron pipe. Pulleys are put on each end of the bed. The pulleys are as wide as the "bed". Each pulley has a steel shaft through it. The shaft turns on a bearing . . . and the pulley turns with the shaft. What is a bearing? When two pieces of steel touch each other; they cannot turn easily without bearings. Bearings use little steel balls to keep the pulley shaft and the conveyor bed from rubbing together. Now the shaft can turn easily. Pulley "A" is the drive pulley. Pulley "B" is the tail pulley. The drive pulley is usually larger because it does the work. The drive pulley is turned (driven) by a motor. A sprocket is put on the drive pulley shaft. A sprocket is put on the motor. What is a Sprocket? A sprocket is a metal "wheel" with "teeth" on the outside. How the drive pulley is "driven" A chain is put around the Drive Pulley Sprocket and the motor sprocket. The chain moves when the motor is started. The chain turns the drive pulley. But.... Because a motor turns very fast (1500 times per minute). . . A SPEED REDUCER must also be used. The SPEED REDUCER is put between the motor and the drive pulley. . . . The motor is connected to the reducer with a V-Belt (like the fan belt in your car) or a "C" Face Coupling. The reducer is connected to the drive pulley with a chain . . . Now the Drive Pulley turns slower. All those parts (the motor, the speed reducer, and the drive pulley) are called: The Conveyor Drive They must be put together to take up as little space as possible - so The motor and reducer are put under and within the conveyor BED. They must be put together to take up as little space as possible - so The motor and reducer are put under and within the conveyor BED. But what about the tail pulley? The tail pulley is located at the tail end of the conveyor and it turns freely. Now a "belt" can be put around the pulleys. The Drive Pulley turns and moves the belt around . . . and around . . . and around. BUT . . . . . . it is dangerous to have the belt hang down under the conveyor bed - So small rollers are put into the Conveyor Bed to hold up the belt. These turn freely -- and just idle. They are called "Return Idlers". Some types of belts stretch more than others What to do? 1. Move the tail pulley! It can be moved to "take-up" the belt stretch. There are "take-up" screws on both sides of the conveyor. Move these screws out slowly. Move them the same amount on both sides! This keeps the belt tight. 2.What do you do when the take-up screws are still all Longer conveyors arethe provided one or more short the way out - and belt stillwith stretches? pieces of belt added, called a "dutchman" Remove the short pieces of belt. Now you can start the "take-up" procedure all over again. NOTE: If a "Dutchman" was not provided, you may need to add an UNDERSIDE TAKE-UP to your conveyor. How to get more belt take-up There is more belt stretch on a long, long conveyor than the regular take-up and dutchman will give. So an "Underside Take-Up" should also be used. When should I use underside take-up? On conveyors 60' long, or more. NOTE: AN UNDERSIDE TAKE-UP is often used when the overall length of conveyor cannot be changed and the TAIL PULLEY "take-up" cannot be used. BELT MOVES AT SPEED OF 20 MTR PER MINUTE This is best speed to move objects from one place to another. A person can walk about 4 miles per hour. If they were carrying a box they would walk much slower. Conveyors move boxes at about the same speed as a person carrying them. This is about 20 mtr per minute (or about 3/4 of a mile per hour). PULLEY IS CROWNED AND LAGGED. A. The drive pulley is larger in the center than the ends. This helps keep the belt in the center. This is called a "Crown". B. The drive pulley is completely covered with vulcanized rubber. It is called "lagging". This keeps the pulley from slipping under the belt. THE CONVEYOR DRIVE IS NORMALLY LOCATED AT THE END TO WHICH THE BELT MOVES. SO A DRIVE PULLEY "PULLS" THE BELT. NOTE: If the belt movement were reversed, the pulley would be pushing the belt. When the conveyor was fully loaded or when the belt stretched, the pulley could turn and not move the belt. THE SNUB IDLER The Snub Idler is closer to the drive pulley. It makes the belt hug more of the drive pulley surface. The Snub Idler is ADJUSTABLE. It is ADJUSTABLE ON BOTH SIDES of the conveyor. (Each side of snub idler can be adjusted independently). Reason - The Snub Idler is used to steer the belt. HHOW TO "STEER" THE BELT When belt runs forward and if it moves toward side "A" move return idler nearest tail pulley on side "Y" toward "B". If belt moves toward side "B" - move return idler on side "X" toward "A". When belt runs in reverse and if it moves toward side "A" - move snub idler on side "X" toward "A". If belt moves toward side "B" - move snub idler on side "Y" toward "B". CENTER DRIVE (Used with Horizontal Belt Conveyors) A. When belt movement is REVERSIBLE (on conveyors 40 ft. long or more) B. When overall length of conveyor cannot change (belt take up by tail pulley increases conveyor length) A center drive should be used because: Drive pulley now "pulls" belt in either direction Take-up pulley can now be used to take-up belt. Different Types of Conveyors Skatewheel conveyors Consist of rows of small metal or aluminum wheels Does not use motors—gravity does all the work Best suited for bringing cartons, sacks and bags down a slope Helpful in shipping areas, moving items down certain lanes for loading into outbound trucks Hard to control the movement of products on these non-powered systems usually confined to short runs and accessible areas Cheap, low maintenance and often portable. Skatewheel Conveyors Wheels are put on axles. Aluminum spacer tubes are put on the axle between the wheels. This keeps wheels from moving from side to side on the axle. Belt conveyors A motor-powered belt atop a constructed bed Widely used in facilities because of their ability to cost-effectively move a wide array of products No problem conveying odd-shaped things and moving items up or down inclines because of the friction produced by the large surface contact area between belt and product Can carry light- and medium-weight goods Low-maintenance systems can transport products to almost any part of the warehouse. Sliding bed conveyors Should be considered if you have to move unstable loads slowly Usually consist of an unpainted metal surface that slides along a bed Excel in transporting odd-shaped products and small items that are not put into totes, because of the generous surface contact area between the solid bed and the product, these systems Are commonly placed at load and assembly stations. Live roller conveyors Consist of elongated rollers placed across a conveying bed Size of the rollers can be adjusted to accommodate the product being conveyed Rollers are powered by belts, chains or line shafts. Often selected by facilities with many assorted products Welcome heavy loads and thrive in dirty or harsh environments However, they can only transport items with solid bottoms and of adequate weight. Loose, lightweight products can fall between the rollers and should thus ROLLER BED CONVEYORS When heavy total loads must be moved, it is best to use a conveyor bed with rollers (instead of regular conveyor bed). This is a Roller Bed belt conveyor Heavy total loads can be moved without using large motors when a ROLLER BED belt conveyor is used. Pneumatic Conveyor Systems •Use of pipes or ducts called transportation lines that carry mixture of materials and a stream of high velocity air. •Materials are such as dry pulverised or free flowing or light powdery materials like cement, fly ash •Carrier systems simply push items from one entry point to one exit point, such as the money exchanging tubes used at a bank drive-thru window. •Dillute-phase systems use push/pull pressure to guide materials through various entry and/or exit points. •Suction or Vacuum systems, Pressure Type systems or a Combination systems Accumulation systems Useful for work-in-process operations or ones that need a buffer Use rollers or belts that start and stop automatically to space cartons as directed by sensors Can back up and set specific items aside without holding up workflow Widely utilized at workstations and for preparing items before they get sorted More costly and need extra controls and motors. The added costs, however, can be recouped by the flexibility that these systems provide What is a Gravity Conveyor? A gravity conveyor moves objects without motor power. WHEELS OR . . . ROLLERS Long belt conveyors •Western Sahara:100 km long, from the phosphate mines of Bu Craa to the coast south of El-Aaiun. •Meghalaya in India to Sylhet in Bangladesh •Conveys limestone at 960 tph and shale from quarry in India to a cement factory in Bangladesh (7 km+ 10 km long) •Engineered by AUMUND France and L& T •Actuated by 3 synchronized drive units for a total power of about 1.8 MW •Manufactured in about 300 meter lengths on the Indian side and 500 meter lengths on the other side MAINTENANCE OF CONVEYORS To get the most out of your conveyor system, your maintenance practices should include far more than just emergency repairs. Maintenance, in general, affects all aspects of operational effectiveness and risks, not just system availability and cost — specifically safety, operational efficiency, energy efficiency, product quality, and environmental integrity. From installation to retirement a comprehensive and important consideration from the day a system is conceived until the day it is retired from service. an essential activity for the achievement of optimum-return-on-investments a key to remaining competitive in a hypercompetitive world. maintenance of conveyor systems divides into three broad categories: Predictive Preventive and corrective Matching application to use Effective management of conveyor life begins with the selection of a system that matches the application for which it’s being used. Different applications require relatively different system components and configurations, especially as it applies to load requirements, operational conditions, cycles-of-use, materials conveyed, operational speeds, and usage period. When a conveyor system is improperly designed — i.e., oversized or undersized — value is wasted, regardless of the maintenance procedures employed. For example, •drive motors that are undersized — relative to the loads being conveyed •Drive motors that are oversized •idlers with low quality components — such as frame, seals, and bearings •Pulleys that are underbuilt for the loads they are •Improperly designed impact areas •An under-built structure Planning to avoid emergency repairs Conveyor maintenance can and should be a straightforward, predictable process — not an emergency event. However, it can easily turn into one. The proper design of a conveyor system assures that power and loads are well balanced and that stress points are within controlled limits. The forces that occur at start-up and at stops can be quite surprising Proper system design is a must for protection of the equipment investment, system safety, system availability, ease-of-maintenance, as well as the longterm, value-producing capability of the entire operation. Maintaining safety Maintenance should only be performed with the conveyor system stopped and electrically locked out. check the entire conveyor for stray tools, parts, or other potential obstacles prior to restarting the system after maintenance activities have been preformed. Maintenance of a conveyor system is not a task for untrained or inexperienced individuals. Predictive maintenance to eliminate surprises Two basic types of predictive maintenance. replacing components at regularly scheduled intervals — usually during scheduled shutdowns — so that total failure of a component is avoided. Another to replace components as indicators of excessive wear or impending failure present themselves Preventive maintenance extends component and system life •the re-lubrication of components at specified intervals •general housekeeping activities •alignment of all components and belt splices. •the removal and replacement of worn or damaged belt sections •tests of electrical components •replacement of wear items — such as motor brushes — at appropriate intervals. Maintenance intervals vary depending on the application hours-of-use quality of components system specifics Corrective maintenance, which involves the replacement of a component after it has demonstrated signs of imminent failure or has, in-fact, failed, should be seen as a last resort. An example is a seized idler roll that must be quickly removed so that the roll “shell” does not have a chance to wear through and possibly cut or damage the conveyor’s belt. conveyor systems be visually inspected on a regular basis for all areas of material buildup should be noted and subsequently removed at shutdown. The causes of material buildup should always be explored Belt surfaces and edges should be inspected for wear or belt delamination. •Problems with bearings and rolling elements •Rollers not rotating with belts Good housekeeping keeps a conveyor running well In areas where contamination is excessive, protective-end shields should be used on the idler and return rolls. Also, in particularly wet areas, special lubricants should be seriously considered. While the conveyor system is shutdown and electrically locked out, the adjustment of skirt boards and belt scrapers should also be considered, if indicated, to compensate for wear or to prevent wear. Additionally, the backside of the belt, return rolls, and pulleys should be inspected to determine if excessive “carryback” is present because this may lead to various forms of belt and component damage. Proper equipment, proper maintenance regular attention to the maintenance of an important system, such as conveying, is a vital part of the job, too. It is just too important to be left to chance and, when properly organized, it is efficient, effective, and non-disruptive. Ultimately, maintenance doesn’t cost, it pays — and it’s all about getting your money’s worth. Protecting all the parts To obtain the optimum return on your conveyor investment, the following components that typically make up a conveyor system must be maintained: Drives Take-up systems Control equipment Belting Pulleys Troughing idlers Return idlers Tail sections Impact-loading equipment Chutes Skirting Belt scrapers Equipment guards Covers Walkways Structure Transfer stations Specialized components associated with site-specific activities. Conveyor maintenance checklist While the system is in operation Check the following issues and refer to all relevant safety warnings and information: •Regularly walk around both sides of the system and note the condition, as well as any unusual behavior of all the moving components. •Note points of material buildup. •Look for any signs of misalignment or improper belt tracking. •Check drive amperage requirements and compare amperages to previous levels for similar loads and conditions. Check the following while system is at rest and electrically locked out: •Confirm that components are in proper alignment •Closely inspect suspect components and take corrective action •Check all safety systems. •Test control equipment. •Check for belt wear — especially at edges and splices — and belt stringing. •Check for damage or wear at loading and transfer points. •Check clearances at chute and skirting areas. Check the following while system is at rest and electrically locked out: •Remove any material buildup on components and clean up any spills along the system. •Relubricate all pillow block bearings •If relubricatable, relubricate troughing and return rolls •Check the condition and functionality of belt scrapers, and adjust or replace •Confirm that all guards and covers are in place. •Replace motor brushes Item to Check Correct Adjustment Conveyor Belt Tension Using hands pushing upward, 3 to 12 mm slack under headshaft at discharge Conveyor Belt Centered Tighten take-up bolt on side which belt is riding nearest or loosen opposite side as required to center belt and achieve proper belt tension Drive Chain Tension & Alignment Tension: 1 mm deflection per 100mm of span Alignment: 1 mm per 200 mm of span Grease Bearings (Located on headshaft and tailshaft) Fill until small bead comes from seal Ratchet Clutch Adjustment, if equipped Compressed length of spring to measure 40 mm Be sure to loosen set screw for adjustment and re tighten upon completion. Oil in Gear Reducer, if equipped Change Oil after the first 250 hrs. Then every 6 months or 2500 hrs of operation COMPONENT ACTION SCHEDULE WEEKLY Check noise. MOTOR REDUCER DRIVE CHAIN Check temperature. MONTHLY QUARTERLY P P Check mounting bolts. P Check noise. P Check temperature. P Check oil level. P Check tension. P Lubricate. P Check for wear. SPROCKETS BELT Check for wear. P Check set screws and keys. P Check tracking. P Check tension. P Check lacing. P BEARINGS (Pulleys & Rollers) Check noise. V-BELTS Check tension. P Check for wear. P Check sheave alignment. P General check: Loose bolts etc. tightened. P STRUCTURAL P Check mounting bolts. P Problem Possible Cause Solution Clutch Ratcheting or slipping Drive chain assembly misalignment or tensioned incorrectly Excessive or Accumulated Load Refer to tension and alignment in Maintenance Chart Carry-Back of Material into Conveyor Avoid load buildup by running conveyor continuously. Do not manually surge load conveyor Replace filled receptacle as required Improper ratchet Refer to ratchet clutch clutch adjustment in tensioning Maintenance Chart Problem Possible Cause Solution Clutch Ratcheting or slipping Damaged or missing chain assembly parts Accumulation of conveyed material or foreign objects inside of casing Excessive Wear on Casing Conveyor not level Review belt and repair or replace as required Reverse conveyor placing ball of newspaper or a rag on belt to act as wipeout for accumulated material Level conveyor Belt misalignment or tensioned incorrectly Refer to conveyor belt tensioning and alignment in Maintenance Chart Problem Possible Cause Solution Excessive Wear/Damage to Belting Belt misalignment or tensioned incorrectly Refer to conveyor belt tensioning and alignment in Maintenance Chart Replaced damaged portion of belting Motor overloads/overheats Foreign object dropped on conveyor belt Ratchet clutch not set properly Refer to ratchet clutch adjustment in Maintenance Chart Grease Bearings as Required (Chart from Service Manual): CONDITIONS SPEED TEMPERATURE OF OPERATING ENVIRONMENT CLEANLINESS OF OPERATING ENVIRONMENT GREASING INTERVAL 100 RPM Up to 50 ° C Clean 6 to 12 Months 500 RPM Up to 65 ° C Clean 2 to 6 Months 1000 RPM Up to 100 ° C Clean 2 Weeks to 2 Months 1500 RPM Up to 100 ° C Clean Weekly Any Speed Up to 65 ° C Dirty 1 Week to 1 Month Any Speed Up to 65 ° C Dirty Daily to 2 weeks Any Speed Any Temp Very Dirty Daily to 2 weeks Any Any Temp Extreme Conditions Daily to 2 A well-executed scheduled maintenance plan can extend the life of your conveyors, make them more reliable, and help prevent expensive downtime. •Check/lubricate all bearings, universal joints, and pulleys. •Check chain tension, wear and lubricate. •Check sprocket alignment, wear, and screw set. •Check flat belt tension, wear and lacing. •Check V-belt tension, wear and sheave alignment. •Check electrical connections at conveyor. •Check gearbox and fill to proper level. •Check general condition of system. •Operate entire system after service. •List any items requiring replacement or repair. Belt Tracking 1. First item you check is the bed for square. which is done by measuring corner to corner. (Figure 1) 2. Make sure that the bed is level from end to end and side to side. If there is more than one bed, run a string from the center of each end to make sure there is no bow in the bed set up. A banana type bow can cause tracking problems. (See Figure 2) Belt Tracking 3.Make sure the drive and take-up pulleys are level with the bed. If the pulleys are not level the belt will track hard to the “low” side. Loosen the bearing bolts on the side that the belt rides toward and adjust the pulley “up” to move the belt toward the center of the pulley. (See figure 3). 4.After you are sure that the conveyor is level and the pulleys are level with the conveyor your next check is the belt tension. Drive Chain Tensioning A loose chain can jump the drive sprockets and can cause sprocket wear and failure. A tight chain requires excessive motor power, and can cause chain and sprocket failure. The slack should be 2% of the span in the following cases: 1. The Drive is vertical or close to vertical 2. The span is greater than 36 inches 3. The Chain is operated under heavy load and high frequency of on-off cycles 4. The direction of the Drive is change often. How to Optimize Conveyor Operations and Productivity •Keep your axe sharp - maintain your conveyor •Know fixes to common problems •conveyor suddenly shuts down •accumulation in one area of the conveyor •drive runs, but the belt doesn’t move •Get to know your load •Shape or form •Dimensions •Orientation •Utilize energy-saving controls and devices •PM & Right equipment •Test for performance •Inspection visually •Function testing •Load testing •Error recovery How to Optimize Conveyor Operations and Productivity •Correctly select and integrate vertical and horizontal conveyors •system throughput requirements •product characteristics •elevation change •number of infeed/discharge points •manual or automated infeed/discharge •interface with horizontal transport devices •proximity to workers •safety devices •Environment •and future system requirements •Safety is essential •42% of the injuries around conveyors occur while performing maintenance,lubrication or other mechanical processes How to Optimize Conveyor Operations and Productivity •Design conveyor workstations with ergonomics in mind •Work surface height •Reach distance •Choose the right belting •kind of load, the need for increased oil resistance, and applications where the load & conveyor may make belt tracking more difficult •Make conveyor technology upgrades •Dynamic Zone Allocation, the system automatically adjusts the conveyor’s zone length to accommodate the length of the carton being conveyed •Loading zone functionality: diff. between load in transport & one that is inserted Energy saving tips in conveyor applications •Select the proper size of conveyor motor for the job •Turn your conveyor off when it's not in use •Use gravity feeds whenever possible •Maintain conveyors for maximum efficiency •Six major causes of drive failure to watch for: bearing failure, winding failures, rotor failures, improper speed-reducer lubrication, improper use of reducer, and poor alignment of the reducer •Design the conveyor system with energy in mind •Upgrade your technology •Consider replacing worn-out conveyors Twelve Fundamental Conveyor Safety Rules •Don’t perform service on conveyor until motor disconnect is Locked Out! •Service conveyor with only authorized maintenance personnel. •Keep clothing, fingers, hair, and other parts of the body away from conveyor! •Don’t climb, step, sit or ride on conveyor at any time! •Don’t load conveyor outside of the design limits! •Don’t remove or alter conveyor guards or safety divides! •Know location and function of all stop/start controls. •Keep all stopping/starting control devices free from obstructions. •All personnel must be clear of conveyor before starting. •Operate conveyor with trained personnel only! •Keep area around conveyors clear of obstructions. Report all unsafe practices to your supervisor! Any Questions?