What are the components of a conveyor system?

29 Apr.,2024

 

A Guide to the Parts and Components Of A Conveyor

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Conveyors, while simplistic in function, are constituted of a multitude of mechanical parts that enable durable, stable, and efficient movement. Much like a car, in its most basic form, a material-handling conveyor uses a motor (engine) and gearbox (transmission) to provide power in a continuous motion.

If you’re considering a conveyor unit or system in your facility, understanding its critical components and operations can assist in routine maintenance, repairs, upgrades, and future system integrations. Each part plays an important role, and grasping the mechanical basics can help you identify when continuous improvement situations occur within a conveyor system.

Belt

A belt is one of the most common applications of conveyance technology. A multi-layered rubber (or similar material) sheeting surrounds the “carcass” or the core of the belt. The carcass is constructed from tightly woven fabric, intertwined with each other within the top and bottom covers of the belt. Belts are wound around the head and tail pulleys on the conveyor bed, powered by the motor. Belts are created in a multitude of materials, sizes, and functions, covering a wide range of material handling applications.

Tip: Conveyor belts are extremely durable, but when rips and tears occur, splicing and vulcanization are relatively simple methods to repair the material.

  • Rubber
  • Fabric
  • Modular plastic
  • Cleated
  • V-belt
  • Curved

Rollers

Rollers are elongated cylinders attached via bearings across a conveyor bed using gravity and low-horsepower motors to move product. Items are propelled forward from spinning roller to roller, or across a belt that is threaded over a bed of rollers.

  • Plastic
  • Steel
  • Rubber
  • Motorized Drive Roller (MDR)
  • Split Roller
  • Pallet Roller

O-Rings

O-rings or O-bands are rubber-based circular bands that are routed in channels on rollers. O-rings allow multiple rollers to spin, keeping constant and stable movement forward as the product passes the section. Without O-rings, a roller would only move as the product skates over it. With O-rings, rollers in front of the package spin with the previous section, ensuring the package does not stop or jam.

Tip: It’s easy to diagnose when an O-ring has failed. Simply search for any rollers that are not spinning when the conveyor section is operating. A single broken O-ring won’t bring a system to a halt, but multiple non-spinning rollers could cause trouble. Fortunately, O-rings are inexpensive and easy to replace.

Pulleys

Conveyor belts are routed through a bed structure via a pulley system to drive movement forward. Pulleys provide stable motion by maintaining belt tension, tracking, traction, and direction. Each pulley in a conveyor bed provides a different function based on its location.

Pulleys are mainly only used for belted conveyors, although some manufacturers do have chain-routed pulleys for live (continuously moving) roller applications.

  • Tail end – Pulley positioned at the conveyor section infeed.
  • Bend – Pulley that directs the belt down to the take-up.
  • Take-up – Situated lower than in the conveyor than the other pulleys, the take-up manages tension for the entire belt route.
  • Snub – Increases traction and stability by providing angled tension to the head pulley.
  • Head – Main pulley that drives the motion forward at the conveyor discharge.

Motor

The engine of the conveyor, an electric motor (or gearmotor) generates energy for the gearbox, providing power to the moving components of the unit. Placed at the discharge end, or center of the conveyor, motors can vary in size, shape, and horsepower. For a single unit, a 2hp or 3hp motor provides adequate power, while faster conveyor systems (like a sorter) require larger, more powerful motors.

  • Drum
  • Side-mounted
  • Under-bed mounted

Conveyor motors come in various types and sizes, depending on the specific application and conveyor configuration. Motors can be AC (alternating current) or DC (direct current) and can have different power ratings, speed capabilities, and torque outputs. Conveyor motors are typically connected to the gearbox or the conveyor pulley or roller, and their speed and direction can be controlled through a variable frequency drive (VFD) or other speed control devices.

In addition to their power and durability, conveyor motors are also known for their low maintenance requirements and ease of use. They can be easily installed, repaired, or replaced, minimizing downtime and improving overall efficiency. Conveyor motors are also energy-efficient, reducing energy consumption and costs while maintaining high-performance levels.

Photo Eyes

Also known simply as a sensor, conveyors use photo eyes to complete functions based on the status captured when product moves on a unit. As a package travels throughout a conveyor system, it passes a multitude of sensors attached to the bed sides that track its movement. This tells the conveyor control module when to stop, go, or redirect the package(s), based on the information provided by every photo eye in a system. This avoids jams and blockages and maintains efficient product flow. Photo-eyes are categorized via their sensing ability and are manufactured either as through-beam sensors, retro-reflective sensors, and diffuse reflective sensors.

A few notable manufacturers of photo-eyes include but are not limited to:

  • Balluff
  • Omron
  • Pepperl+Fuchs
  • Sick AG
  • Rockwell Automation
  • Turck Inc.
  • Allen-Bradley

Bearings

Bearings play a critical role in the smooth operation of conveyor systems. Serving as the mechanical interface between moving parts, bearings provide support, reduce friction, and facilitate the motion of the conveyor belt. They are typically mounted on conveyor rollers, pulleys, and other rotating components, allowing them to rotate freely while minimizing wear and tear. Bearings enable the efficient and reliable movement of the conveyor belt, helping to transport materials smoothly and consistently.

Properly functioning bearings are essential for preventing belt misalignment, reducing downtime, and extending the overall lifespan of the conveyor system. With their crucial role in ensuring reliable and smooth conveyor operation, high-quality bearings are a key component in maintaining the performance and productivity of conveyor systems.

Brakes

Brakes are an important safety feature in conveyor systems, providing control and stability during operation. These mechanical devices are designed to halt or slow down the movement of the conveyor belt or specific conveyor components. Brakes can be applied in various ways, including drum brakes, disc brakes, and caliper brakes, depending on the specific conveyor system’s requirements.

One of the key benefits of brakes in a conveyor system is enhanced safety. They can prevent conveyor belt slippage, which may occur during sudden stops or in emergency situations, reducing the risk of accidents or injuries. Brakes also allow for precise control over the conveyor’s speed, direction, and positioning, helping to avoid damage to materials, equipment, or personnel.

In addition to safety, brakes also provide operational flexibility. They allow for smooth and controlled stops, starts, and changes in direction, which can optimize the conveyor system’s performance. Brakes enable the conveyor to handle varying loads, inclines, or declines, ensuring consistent and reliable operation.

Guardrails & Supports

Guardrails and supports are crucial components of a conveyor system, providing stability, safety, and structural integrity. Guardrails, typically installed along the sides of the conveyor, serve as a physical barrier to prevent materials from falling off the conveyor belt or interfering with surrounding equipment or personnel. They help to contain and guide the materials being transported, ensuring that they stay on the conveyor and do not pose a hazard to the surrounding environment.

Supports, on the other hand, are used to provide structural stability and maintain proper alignment of the conveyor belt. They are usually positioned underneath the conveyor belt and provide support to the conveyor frame, rollers, and other components. Supports are designed to withstand the weight of the conveyor system, the materials being transported, and any additional loads or impacts that may occur during operation.

Guardrails and supports are typically made of durable materials, such as steel or aluminum, to provide strength and durability to the conveyor system. They are often adjustable and customizable to accommodate different conveyor configurations, heights, and widths. Guardrails and supports may also be equipped with additional features, such as guide rails, brackets, or brackets, to ensure proper alignment, prevent material spillage, and optimize conveyor performance.

Gearbox

A gearbox is a critical component in a conveyor system, serving as a mechanical power transmission device that controls the speed and torque of the conveyor belt. It is typically connected to the motor and the conveyor pulley or roller, and its main function is to convert the rotational speed and torque from the motor to the desired speed and torque for the conveyor belt.

Gearboxes contain a set of gears with different sizes and arrangements, which determine the gear ratio and subsequently the output speed of the conveyor belt. The gear ratio can be adjusted to suit the specific requirements of the conveyor system, allowing for precise control over the belt speed, direction, and performance. Gearboxes can be configured with various gear types, including:

  • Spur
  • Helical
  • Bevel
  • Worm

Gearboxes also provide torque multiplication, allowing the motor to generate higher torque at the conveyor pulley or roller, which is essential for overcoming the resistance and friction of the conveyor belt and the materials being transported. This enables the conveyor system to handle heavy loads, inclines, or declines, while maintaining the desired belt speed and performance.

Gearboxes play a crucial role in protecting the motor and the conveyor system. They can absorb shocks and vibrations, smooth out the power transmission, and prevent excessive wear on the motor and other conveyor components. Gearboxes also provide safety features, such as overload protection, by using clutches, brakes, or other mechanisms to prevent damage to the motor or the conveyor system in case of excessive loads or sudden stops.

Need help with your conveyor system? Century Conveyor Systems Inc. has over 40 years of conveyor service experience and boasts a full department of maintenance technicians and equipment experts. Learn more about our extensive capabilities at our On-site Conveyor Service page.

Belt Conveyors: Components, Types, Design, and ...

Belt Conveyors

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Introduction

This article will take an in-depth look at belt conveyors.

The article will bring more understanding on topics such as:

  • Belt Conveyors and their Components
  • Types of Belt Conveyors
  • Design and Selection of Belt Conveyors
  • Applications and Benefits of Belt Conveyors
  • And Much More…

Chapter 1: Belt Conveyors and their Components

This chapter will discuss what a belt conveyor is and its components.

What is a Belt Conveyor?

A belt conveyor is a system designed to transport or move physical items like materials, goods, even people from one point to another. Unlike other conveying means that employ chains, spirals, hydraulics, etc., belt conveyors will move the items using a belt. It involves a loop of a flexible material stretched between rollers that are actuated by an electrical motor.


Because the items being transported vary in nature, the belt material also varies by the system it is employed in. It commonly comes as a polymer or a rubber belt.

Components of a Belt Conveyor

A standard belt conveyor system has a head pulley, tail pulley, idler rollers, belt, and frame.


Head Pulley

The head pulley is coupled with the actuator and the electric motor. It drives the conveyor, acting as the pulling force. The head pulley is located at the point that the conveyor offloads, known as the discharge end of a belt conveyor. Since it drives the whole system, it is often necessary to increase the traction of its belt with a rough jacket covering its outer surface. The jacket is referred to as a legging.


The head pulley usually has the largest diameter of all the pulleys. Sometimes a system can have multiple pulleys that act as drive pulleys. The pulley at the discharge end, is a drive roller usually with the biggest diameter, and will be identified as the head pulley.

Return or Tail Pulley

This is located at the loading end of the belt conveyor. Sometimes it comes with a wing shape to clean the belt by letting material fall aside to the support members.

In a simple belt conveyor setup, the tail pulley will be mounted on guides usually slotted to allow the belt’s tension. In other belt conveying systems as we shall see, tensioning of the belt is left to another roller called the take-up roller.

Idler Roller

These are rollers employed along the length of the belt to support the belt and load, prevent sagging, align the belt, and clean up the carryback (material left sticking on to the belt).

Idler rollers can either do all of the above or any one of them, but in any space, they will always act as support for the belt.


There are many different idler rollers for different functions, as listed below:

Troughing Idlers

Troughing idlers will have three idler rollers set up in a configuration that makes a “trough” of the belt. They are located on the side that carries the load on the belt conveyor. The idler in the center is fixed, with the two on the ends able to be adjusted. This is so the angle and depth of the trough can be varied.


These idlers, when employed, will reduce spillages and maintain a constant cross-sectional area along the length of the belt conveyor. Maintaining a constant cross-sectional area is important for stability.

Rubber Disk Idler

This idler has rubber disks placed at set distances along the axis of the roller. On the extreme ends, the rollers are much closer so that they can support the belt edge, which is prone to tear. The spaced-out disks will break off any connected carryback/ leftover material and reduce material building up on the bottom of the belt. This is a common cause for mistracking (when the belt shifts to one side of the system and causes misalignment).


Screw Idler Roller

Sometimes the disks are helical like a screw and the idler will be called a rubber screw idler roller. The function will remain the same. An example of a screw idler roller is depicted below.


The screw idler can also be made out of rubber helix. Screw idlers are most common where a scrapper that takes off carryback would not be feasible, especially on mobile belt conveyors.

Trainer Idler

Trainer idlers keep the belt running straight. It works against mistracking. It achieves this by a central pivot that swerves the roller back to the center should the belt drift off to one side. It also incorporates two guide rollers to act as guides for the belt.


Conveyor Belt

In setting up a belt conveyor, the belt is perhaps the most intricate.The tension and strength are important since the belt takes a lot of punishment when loading and ferrying the material.


The growing demand for longer conveying lengths has catalyzed the research into new materials, though this always comes at a cost. Stronger belts that adhere strictly to environmentally friendly rules tend to come with high setup costs, sometimes the costs can hardly even be justifiable. On the other hand, if an economical approach is taken, the belt usually fails, resulting in high operating costs. Costs for the belt should usually range below 50% of the total cost for the belt conveyor.

A belt is made up of components such as:

Conveyor Carcass

Since this is the skeleton of the belt, it has to provide the tensile strength needed to move the belt and the lateral stiffness for supporting the load. It must also be capable of absorbing loading impact. The belt is a loop so it has to be joined; this is known as splicing. Because some of the splicing methods require the use of bolts and fasteners, the carcass must be able to provide an adequate and firm base for these fasteners.


The carcass is commonly made of steel cord or textile ply. Textile ply is made from fibers like aramid, polyamide, and polyester. If only one ply is used, a PVC-coated textile carcass is also common. Carcasses can have even six layers piled on each other. The carcass can also include the edge protection that is very much needed in bulk conveyor belts.


Conveyor Covers (Top and Bottom & Sides)

This is a flexible material made of rubber or PVC. The covers get exposed directly to the weather elements and the working environment. Careful consideration of the covers must be made depending on the intended use. The following usually require attention, flame resistance, low-temperature resistance, grease and oil resistance, anti-static, and food grade.


The carrying side of the conveyor depending on the load, the angle of inclination of the conveyor, and general use of the belt all have special features. It can be corrugated, smooth, or cleated.


Other applications like scrap conveyors in CNC machines will employ a steel belt conveyor since this won’t wear as much as other conventional materials would do.


In food processing industries, PVC, PU, and PE belts are also used for the preservation of food and to minimize contamination.


Plastic belts are fairly new, though due to their vast advantages, they are slowly gaining momentum. They are easy to clean, have a wide temperature range, and have good anti viscosity properties. They are also resistant to acids, resistant to alkaline substances, and saltwater.

Conveyor Frame

The frame, depending on the loading, height of operation, and distance to be covered will vary. They can come in a simple setup that can be represented by a cantilever. They can also be trusses in the case of larger loads. Extrusions of Aluminum are also employed for simple and lightweight operations.


The frame design is a critical aspect of conveyor design. A badly designed frame can cause:

  • Belt running out of track
  • Structural failure which results in:
    • Long downtimes which translate to delays in production
    • Injuries and casualties
    • Costly Spillages
  • Expensive fabrication methods and installation.

On the frame, other accessories can also be mounted like walkways and lighting as depicted above. Lighting situations will require sheds and guards to protect the material. Loading and discharge chutes can also be mounted. Knowledge of all these possible add-ins is important to avoid uncalculated overloading.

Chapter 2: Types of Belt Conveyors

This chapter will discuss the types of belt conveyors. These include:

Roller Bed Belt Conveyor

The surface just under the belt on this version of a conveyor belt is made of a series of rollers. The rollers are closely stacked so that there is hardly any sagging of the belt.


They are suitable for both long and short distance conveying. In some instances, they can be so short that they only employ two rollers for the entire system.


When using gravity to load, the roller belt conveyor is one of the best options to pick. If one used manual loading, the shock would damage the rollers easily since they usually have internal bearings. These bearings plus the generally smooth surface of the rollers greatly reduce friction which makes it easy for conveying.

Roller bed belt conveyors are used mainly where there is hand sorting, assembling, transporting, and inspection. Examples include in:

  • Airport baggage handling
  • Courier items sorting including postal offices

Flat Belt Conveyor

The flat belt conveyor is one of the most common conveyor types. It is typically used to transport items within a facility. Internal conveyance requires a series of powered rollers/ pulleys to pull the belt.


The belts employed for the flat belt conveyor vary from fabrics, polymers to natural rubbers. Because of this, it becomes versatile in terms of materials to be transported. It is also very easy to align with the tail pulley usually mounted so it can be adjusted to align the belt. It is generally a low speed conveyor belt.

The flat belt conveyor applications include:

  • Slow assembly lines
  • Washdown applications
  • Light dusty industrial assembly

Modular Belt Conveyor

In contrast to flat belt conveyors that use a “seamless” loop of a flexible belt, Modular Belt conveyors use a series of interlocking rigid pieces commonly made from plastic or metal. They function more like a chain does on a bicycle.

This gives them a huge advantage over their flexible belt counterparts. It makes them rugged because they can work over a wide range of temperatures and PH levels.


When a section of the belt becomes damaged, one can easily replace that particular section alone rather than the flexible belts where the entire belt would have to be replaced. Modular belts can travel, using only one motor, around corners, straight lines, inclines, and declines.

As much as other conveyors can do the same, it comes at the cost of complexity and funds. For applications that may require the “unorthodox” width greater than the length, type of conveyor, modular belt conveyors will achieve that feat much easier.

Since they are non-metallic, easy to clean, and porous to gas and liquids, modular belt conveyors can be applied in:

  • Food handling
  • Fluid handling
  • Metal detection

Cleated Belt Conveyor

Cleated belt conveyors will always have a barrier or cleat in their design. The cleats work to separate equal segments on the belt. These segments keep particles and materials that might otherwise roll back or fall off the conveyor during inclines and declines.

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The cleats come in different shapes and sizes which include:

Inverted Capital T

This cleat will be standing at 90 degrees to the belt to give support and flexibility to delicate items. It is most suited to do light jobs and handling small parts, packaged goods, and food products.


Forward- Leaning Capital L

Because of its orientation, it can easily resist leverage forces. It can be used to scoop granules and hold them against gravity. It can be employed to hold light to medium weight granules.


Inverted V Cleats

These cleats are less than 5cm in height to have the same effect that a trough has. They can be used to transport heavy or big bulks of material because of their relatively short cleat, which can withstand high impacts.

Lugs and Pegs

These cleats are used to aid the runoff of liquids after washing off items like vegetables and fruits. Lugs and pegs are a cost-effective way to convey substances and items that do not need to be supported all along the length of the belt such as large cartons or rods. They can also be used to selectively move products that exceed a wanted size and even hold single products in place.

Other uses of Cleated Belt Conveyors include:

  • Escalators are a modification of cleated belt conveyors in a sense they carry loose materials up an incline that is steep.

Curved Belt Conveyor

This conveyor uses a frame that is fabricated already curved so as to carry items around tight corners. It is used where space is limited and winding conveyors would save space. The curves can go as steep as 180 degrees.

Modular plastics with interlocking segments are used but only if the conveyor has a straight run before it curves. Flat flexible belts will be used if the belt is primarily only curved.


Incline/Decline Belt Conveyor

Incline conveyors require tighter tension force, higher torque, and traction on the belt surface to prevent items from falling off the belt conveyor. Thus, they will incorporate a gear motor, a center drive, and a take up. The belt must also have a rough surface to allow for greater traction.


Just like cleat conveyors, these also carry items up a gradient not letting the items fall off. They can also be used to boost the gravitational flow of fluids.

Sanitary Washdown Conveyor

In the pharmaceutical and food industries, sterilization and harsh washing usually need to happen, in line with health and safety guidelines. Washdown and sanitary conveyors are designed to handle sanitary procedures of that nature. The belts employed here are usually flat belts that are relatively thin.


Sanitary wash-down belt conveyors are used in items coming from extreme temperatures like freezers and furnaces. Sometimes they have to work in hot oil or glaze. Because of how well they can handle greasy environments, they are sometimes used to offload oil drums and crates from ships.

Troughed Conveyors

A troughing belt conveyor is not a distinct type of belt because troughing can be incorporated in any conveyor type.


It utilizes a belt that forms a troughed shape because of the troughing idler rollers under it.


The troughing idler rollers have a central roller that has a horizontal axis of rotation, the outer two rollers (wing rollers) have an axis lifted at an angle to the horizontal. The angle is usually around 25 degrees. Troughing only happens to the top idler rollers and never really at the bottom.

Higher angles of troughing will cause permanent damage to the belt. If the belt is troughed at steeper angles, it will retain its cup shape and will become difficult to clean, difficult to track as well as break the carcass of the belt. It also might reduce the amount of surface contact with the idler rollers, which ultimately reduces the efficiency of the belt conveyor system.


Trough belts usually operate in one plane, which is either horizontal or inclines, but inclines that are only until 25 degrees. The belt must have a radius big enough so that it can still touch all the rollers in the troughing idler. A sharper angle of troughing means the belt will not touch the center idler roller, thereby undermining the structural integrity of the belt as well as the efficiency of the conveyor system at large.

Magnetic Belt Conveyor

Magnetic belt conveyors are a transport device used to position and control ferrous metal pieces and parts. They use ferrite or neodymium magnets to transport materials and are ideal for small parts that would not normally fit on a traditional belt conveyor. Magnetic belt conveyors function exactly like traditional belt conveyors. What differentiates magnetic belt conveyors from other conveying systems is their use of magnets to take advantage of material’s magnetic properties.

The magnets on a magnetic belt conveyor are spaced along the bed of the conveyor with sufficient power to resist the effects of gravity. The size of the size the materials has little effect on the efficiency of a magnetic belt conveyor since the strength of the magnets can be changed to meet different conditions and requirements.

Types of Magnetic Belt Conveyors

Magnetic Belt Conveyors - Magnetic belt conveyors are the most common type of magnetic conveyor because they are easy to construct and operate. They have a magnetized sheet metal belt with permanent magnets or a series of electromagnets that force ferrous materials to stick to the conveyor belt.

Aside from the presence of the magnets, magnetic belt conveyors function like traditional belt conveyors. They are used to move cans of goods, parts, ore, and other metals with magnetic properties and can move products vertically, up inclines, and upside down.

Magnetic Separator Belt Conveyors - Magnetic separator belt conveyors are a specially designed type of magnetic conveyor that are used to separate ore from loose dust and debris. As material moves along the belt, non-magnetic material falls to the side while magnetic material adheres to the belt. Magnetic separator conveyors are divided into dry and wet types. The difference between the two is that dry types do not have to have materials wet to do the separation while the wet type requires material to wet.


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    Chapter 3: Design and Selection of Belt Conveyors

    When designing a conveyor belt, the major parameters to be considered are:

    • Motor and gearbox selection
    • Speed of belt
    • Tension and take-up
    • Material to be conveyed
    • The distance over which to be transported
    • Working environment e.g. temperature, humidity, etc.

    Motor and Gearbox Selection

    To aid the selection of the motor, one must first know what the effective pulling force required for the conveyor is.


    For a simple horizontal conveyor, the effective pulling force is given by the formula below:

    Fu=µR · g(m+ mb+ mR)

    Where:

    Fu=Effective pulling force

    µR =Friction Coefficient when running over roller

    g = Acceleration due to gravity

    m =Mass of goods conveyed on the whole length of the conveyor

    mb =Mass of Belt

    mR =Mass of all rotating rollers minus mass of drive roller

    For a system on an incline, the effective Pulling force is given as below:


    Fu=µR · g · (m + mb+ mR) + g · m · sina

    Where

    Fu =Effective Pulling Force

    µR =Friction Coefficient when running over roller

    g = acceleration due to gravity

    m = mass of goods conveyed on the whole length of the conveyor

    mb =Mass of Belt

    mR =Mass of all rotating rollers minus mass of drive roller

    a =Angle of inclination

    Once the pulling force is determined, it becomes easy to come up with the torque and hence the motor to use and the gearbox will follow after.

    Speed of Conveyor

    The speed of the conveyor will be the circumference of the drive pulley multiplied by the revolutions per unit time.

    Vc=D · F

    Vc =Speed of conveyor belt in ms-1

    D =Diameter of drive pulley in meters.

    F =Revolutions of drive pulley per second

    Tension and Take-up of the Belt

    Take-up is an important component in maintaining and achieving optimum belt tension. This will contribute greatly to the process and its mechanical stability.

    A properly tensioned belt will wear evenly and will contain material evenly in the trough and run centrally when going over the idlers.


    All conveyors will always experience some stretch in their length and width. Generally, it is acceptable that a new belt will stretch with an additional 2 percent of its original length. Since this fraction will add to the length of the belt, the entire belt will have a slack. This slack will have to be taken up in order to retain optimum tension.

    The longer a conveyor is, the bigger the stretch will be. Using the 2 percent stretch, a 2-meter long conveyor can stretch 40mm, but a 200-meter long conveyor will slack 4 meters.

    Take up is also profitable when the belt has to undergo maintenance. In such a case the take-up is simply let loose and the personnel will undertake maintenance with ease.

    Types of Belt Conveyor Take-Ups

    There are many configurations of take-ups, each having its own pros and cons. The common configurations of belt conveyor take-up are the gravity take-up, screw take-up, and the horizontal take-up.

    Screw Take-Up

    The screw take-up configuration uses mechanical force to take up all the slack in the belt. It achieves it by adjusting a threaded rod that is attached to one of the rollers, especially the tail roller. This threaded rod will be on each side of the roller so it can also work as an alignment procedure. Since this is a hands-on manual approach, screw take-up is often called manual take-up.


    Another style is called the top angle take-up. Though it is also popular, it needs a large and heavy tail frame to archive. The guards also have to be large.

    Screw take-ups are a cheap and effective way of controlling belt tension for relatively short conveyors and are the easiest and standard take-up choice for many.

    Gravity Take-Up

    Screw take-ups are usually not suited to lodge the length of the stretch that happens in conveyors longer than 100 meters. In these setups, gravity take-up will be the best approach to belt tensioning.

    A gravity take-up assembly uses three rollers where two are bend rollers and the other one will be a gravity or sliding roller that routinely manages the belt tension. A counterweight that will be mounted to the gravity take-up roller pulls down on the belt to preserve tension through gravity. The bend rollers direct the belt slack around the gravity take-up roller.

    The full take up assembly is integrated into the bottom of the conveyor frame and makes a continuous tension on the belt. This way of self-tensioning arrangement allows the take-up to easily adjust to sudden spikes in tension or load.

    So, the gravity take-up method always maintains the appropriate belt tension and avoids damages to the belt because of sudden load or tension spikes. Since gravity tensioners are self-tensioning, they need less maintenance, unlike the screw take-up method.

    Their maintenance is normally needed when the belt has reached the end of its lifespan. That is when it has stretched such that the assembly will have reached the bottom of the set travel distance. When this happens, the conveyor belt will either need replacement or cut and vulcanized. A gravity take-up system is also known as an automatic take-up because it adjusts automatically.

    Horizontal Take-Up

    The horizontal take-up is a substitute for gravity take-up but only when space is limited.

    This take-up is similar to gravity take-up, but instead of the assembly being located below the belt, it is situated vertically behind the tail roller. This makes it especially beneficial when the conveyor is located on a grade that does not have any additional space under the conveyor.


    Because the horizontal take-up will not fall below the conveyor, an arrangement of cables and pulleys is used for tensioning the belt with a weight box. The cables attached to the tail pulley, rides on a carriage which then allows it to be moved in and out of place.

    Chapter 4: Applications and Benefits of Belt Conveyors

    This chapter will discuss the applications and benefits of belt conveyors. It will also discuss common belt conveyor problems, their causes, and the environmental effects on belt conveyors.

    Applications of Belt Conveyors

    Conveyor belts have a wide range of applications across industries. These include:

    • Mining Industry
    • Bulk handling
    • Processing plants
    • Taking ores from the shaft to the ground level
    • Automotive Industry
    • Assembly line conveyors
    • CNC machines’ scrap conveyors
    • Transport and Courier Industry
    • Baggage handling conveyors at airports
    • Packaging conveyors at courier dispatch
    • Retailing Industry
    • Warehouse packaging
    • Till point conveyors

    Other conveyor applications are:

    • Food handling industries for grading and packaging
    • Power generation conveying coal to the boilers
    • Civil and construction as escalators

    Chapter 5: Types of Belt Conveyor Pulleys

    Pulleys are a necessary and essential part of belt conveyors. They help in providing drive tension and changing the direction of the movement of the belt. Belt conveyor pulleys are classified as drive, tension, motorized, snub, wing, and bend pulleys that can be smooth, rubber coated, or cast rubber.


    Motorized Pulley or Motor Drum

    Motorized pulleys are the driving device for a belt conveyor system and consist of a sealed motor and a protected exterior drum, which is driven by the electric motor. The drum supplies traction to drive the conveyor belt. As with most pulleys, motorized pulleys come in a variety of configurations to meet the wide assortment of needs of conveyor manufacturers.

    Drive Pulley or Head Pulley

    The drive pulley supplies traction to a conveyor belt. Its surface is coated with chevrons or diamonds to supply enough friction between the belt and pulley to move the conveyor belt. They are single or double sided with one or two drives. The number of drive pulleys for a conveyor system is determined by the size of the system.

    Bend Pulley

    A bend pulley changes the winding direction of a belt conveyor such that it forms a closed loop. They are used as the tail roller to form the tension roller of the tensioning device and can cause the belt to be redirected. Bend pulleys have the same design as return pulleys with a smaller diameter.

    Tension Pulley

    A tension pulley is a return pulley used to create tension on the conveyor belt, which increases the amount of force placed on the pulley. In order to be able to endure the forces placed on the pulley, tension pulleys are solid pulleys. They have multiple uses and are used as return pulleys or can be positioned in any place along the belt. Their preferred position is as close as possible to the drive pulley.

    Snub Pulley

    The snub pulley works with the drive pulley. It is used to enlarge the touching areas between the belt and drive pulley. Snub pulleys increase the friction between the conveyor belt and the drive pulley, which makes them ideal for systems that require high drive power or where the conditions are contaminated.

    Wing Pulley

    The purpose of a wing pulley is to clear material on the return belt. It is constantly cleaning itself and has excellent traction. There are several different types of wing pulleys including spiral, heavy duty, herringbone.

    Magnetic Pulley

    Magnetic pulleys are part of magnetic conveyor belts and are part of the process of separating ferrous material from non-ferrous materials. They are made of steel with enclosed permanent magnets. As with all magnetic conveyors, they are capable of removing large and small ferrous debris.

    Crowned Head Pulley

    A crowned head pulley has a cylindrical middle and tapered ends to help a conveyor belt to be driven without wobbling. They are used with flat belt drives to increase and improve stability. Crowned head pulleys use their tapered ends to force a flat conveyor belt back to the center.


    Chapter 6: Advantages and Problems with Belt Conveyors

    The common assumption regarding belt conveyors is that they are a convenient and easy method for moving, sorting, packing, and shipping of goods and products. They have existed for years in various forms and have made a dramatic change in supply chain efficiency.

    Advantages of Belt Conveyors

    The advantages of belt conveyors include:

    • It is a cheap way of moving materials over long distances
    • It doesn’t degrade the product being conveyed
    • Loading can be done at any place along the belt.
    • With trippers, the belts can offload at any point in the line.
    • They do not produce as much noise as their alternatives.
    • Products can be weighed at any point in the conveyor
    • They can have long operating times can even work for months without stopping
    • Can be designed to be mobile as well as stationary.
    • Have less dangerous hazards to human injury
    • Low Maintenance costs

    Common Belt Conveyor Problems

    Regardless of the advantages of belt conveyors, they are complex pieces of equipment that have to be monitored and managed. Some of the concerns that need to be checked are:

    Problem 1: The Conveyor Runs to One Side at a Certain Point in the System.

    The causes of this would include:

    • Material building upon the idlers or something causing the idlers to stick
    • Idlers no longer run square to the path of the conveyor.
    • Conveyor frame tilted, crocked, or no longer level.
    • Belt was not spliced squarely.
    • Belt is not loaded equally, probably loaded off-center.

    Problem 2: The Conveyor Belt Slips

    The causes of this would include:

    • Traction is poor between belt and pulley
    • Idlers stuck or not rotating freely
    • Worn out pulley legging (the shell around the pulley that helps increase friction).

    Problem 3: Overstretching of the Belt

    The causes of this would include:

    • Belt tensioner is too tight
    • Belt material selection not done properly, probably “under belted”
    • Conveyor counterweight is too heavy
    • The gap between idler rolls is too long

    Problem 4: The Belt Wears Excessively at the Edges

    The causes of this would include:

    • Belt is loaded off-center
    • High impact of material on the belt
    • Belt running against conveyor structure
    • Material Spillage
    • Material is trapped between belt and pulley

    Environmental Effects On Belt Conveyors

    Water, petroleum products, chemicals, heat, sunlight, and cold all influence the belt conveyor’s performance and life.

    The causes and the effects can be categorized as:

    Moisture Effects

    • Belt rots and cracks
    • Belt loose adhesion
    • Causes slippage
    • Steel carcasses can rust

    Effects of Sunlight and Heat

    • Rubber will dry out and weaken
    • Rubber will crack
    • Rubber may have more slack and thus reduce belt tension

    Cold Effects

    • Belt stiffens and becomes harder to guide and train
    • On incline systems, frost can build up and cause slippage
    • Ice can build up in chutes and clog them

    Effects of Oil

    • Rubber will swell
    • Rubber will lose tensile strength
    • Rubber will lose tensile strength
    • The belt will wear quicker
    • Rubber will lose adhesions

    Conclusion

    A belt conveyor is a system designed to transport or move physical items like materials, goods, even people from one point to another. Unlike other conveying means that employ chains, spirals, hydraulics, etc., belt conveyors will move the items using a belt. It is critical to be cognizant of the design considerations and applications of various belt conveyors depending on the intended use.

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