Conveyors Flashcards
What are the four basic components that make up a belt conveyor?
- frame with carrying and return idlers
- drive (head) pulley
- return (tail) pulley
- tensioning device
On belt conveyor, this component transmits power to the belt and is always located at the discharge end.
The head pulley
The point of highest tension on a belt is right before the head pulley.
On a belt conveyor, what is the point of highest tension on the belt?
Right before the head pulley
On a belt conveyor, which pulley is located on the discharge end of the coveyor?
The head pulley
On a belt conveyor, which pulley is located at the intake end of the coveyor?
The tail pulley
This is usually where the tensioning device is installed.
What are two types of bends introduced into belt conveyor frames when moving material up or down an incline?
- convex bends
- concave bends
Which conveyor system has the lease cost per tonnage?
Belt conveyors
This, along with their ability to conform to local conditions, makes them one of the most flexible and widely used transportation systems.
On a belt conveyor system, what is a tripper?
A device that allow discharge of material from the side of a belt conveyor
At either selected points, or any point along the length of the conveyor.
This belt conveyor component is usually a frame that supports a series of idlers, head pulley and a tail and snub pulley, which elevates the main belt over the frame allowing material to discharge into a chute or transverse belt.
A tripper
True or false: A belt conveyor tripper may be self-propelled or attached to a stacker.
True
This component of a belt conveyor system is used to provide a constant stream of material to the belt.
Feeders
These ensure that there aren’t unloaded or overloaded spots along the belt, which can result in spillage when excess material falls from the edge of the belt.
What are three accessories that can be use with belt conveyor feeders to know the tonnage rate delivered to the conveyor?
- variable feed drives
- adjustable feed gates
- load cells
True or false: Belt conveyor feeder belts are a lot wider than regular conveyor belts and tend to be flat.
True
The feeder belt may have raised edges to prevent spillage.
Where are the highest wear points on belt conveyors?
At the loading points
This is where the most impact and abrasion occurs.
What is done with belt conveyors to reduce the impact and abrasion that occurs from loading material onto the belt?
Load the material at the same speed and in the same direction as the belt
This can be done with transition conveyors and/or chutes.
When loading belt conveyors, why is it a good idea to load the belt as close to the centre of the belt as possible?
To prevent tracking issues.
The belt can move to one side due to impact force
On belt conveyors, loading and unloading is done in the ________ zones.
transfer zones
What are the four main advantages of transition belt conveyors?
- correctly position the material
- impact force reduction
- shorter belt ⟶ ease of maintenance
- can be fitted with load cells
How do transition conveyor belts help to eliminate tracking problems?
By loading the material into the centre of the main belt
How do transition conveyor belts reduce the impact loading forces on the main belt?
By reducing the transfer height
The transition belt takes the large impact forces.
On belt conveyor systems, after the feed rate has been established, this accessory is used to control the direction, speed and placement of the material on the main belt.
In-line chutes
On belt conveyor systems with in-line chutes, the chute is angled and extended in the direction of belt travel. Why is this?
To direct the material onto the centre of the belt at close to belt speed.
This reduces impact and abrasion damage done to the belt.
On belt conveyor systems with in-line chutes, why is the material directed to the centre of the belt at close to belt speed?
To reduce impact and abrasion damage done to the main belt.
On a belt conveyor system, what type of chute is required if the receiving conveyor is positioned to an angle to the unloading conveyor?
A side loading chute
This type of chute requires more space to redicect the material to the receiving conveyor, which results in a greater height difference between conveyors when compared to in-line chutes.
Which type of belt conveyor chute would require more space: an in-line chute or a side loading chute?
A side loading chute
This additional height can result in higher impact forces on the receiving belt if baffles are not used.
On a belt conveyor system, what is used in side loading chutes to slow the material and direct it to the centre of the receiving belt?
Baffles
These are required to slow the material down, as side loading chutes require more height than in-line chutes, which results in greated impact forces on the receiving belt.
What should be done to chutes on belt conveyors systems if the material is abrasive?
Liners should be installed.
These can be made or ceramic tile or metal plating.
When installing a chute on a belt conveyor system, what can happen if the material isn’t loaded in the centre of the belt?
Tracking and spillage issues
When installing a chute on a belt conveyor system, what can happen if the material is loaded in the opposite direction to belt travel?
Excessive wear on the belt
True or false: On belt conveyors, chutes should be steep enough to prevent wet material from sticking and building up on the chute walls.
True
What dictates the graduated idler spacing on belt conveyors?
The load
Load ↑ = Spacing ↓
The greater the load, the closer together the idlers need to be spaced to ensure proper belt support.
When it comes to belt conveyors, what is a rock box?
A type of chute or receiving hopper located at the discharge point of the head pulley.
These are used to reduce the impact and abrasion damage caused by certain types of materials as they transition into a chute.
On belt conveyors, where are rock boxes located?
At the head pulley
The discharge end of the belt.
These are used to reduce impact and abrasion when materials transition from a belt to a chute.
This belt conveyor accessory works by filling with an initial flow of material and then spilling excess material down a chute, with the initial flow of material absorbing most of the impact and abrasion caused at this transfer zone.
A rock box
On a belt conveyor system, how does a rock box work to reduce abrasion and impact on chutes?
By using some of the conveyed material to absorb the impact and abrasion.
On belt conveyors, what is the main disadvantage of a rock box?
Some material remains in the rock box
These cannot be used with more than one material if material contamination is a concern.
On belt conveyors, this accessory is used at the discharge point when the material contains large lumps to allow the fine material to trickle through the bars to the belt underneith to act as a cushion for the lumps, reducing belt wear.
Screens or grizzly bars
On belt conveyors, what is the purpose of skirtting and skirt boards?
To confine the material and prevent spillage until the material has reached belt speed.
These are attached to the bottom of chutes and extend along the belt.
On belt conveyor systems, what is the recommended clearance between the bottom edge of a skirt board and the belt?
1” clearance
This ensures the skirting doesn’t rub against the belt.
On belt conveyors with skirting and skirting boards, what is held to the skirting board with the backing strip?
A soft rubber strip
This is the skirting, and is the component that rubs against the belt.
This should never be substituted with old belt material, as this will wear the belt.
On conveyor belts, the skirt boards are sometimes extended further along the conveyor and are closed in on the top. Why is this done?
To control dusting at the loading/unloading point
This is done with dry, fine material.
The chute and/or skirt box may be connected to a dust collector.
What is another name for the head pulley on a belt conveyor?
The drive pulley
These are always located at the discharge end.
What is another name for the tail pulley on a belt conveyor?
The return pulley
This component of a belt conveyor system is used to create sufficient tension on the belt to maintain a positive driving force between the belt and the drive pulley.
Belt take-ups
The type of take-up depends on the design and location of the conveyor.
True or false: On belt conveyors, belt take-ups must be flexible enough to accomodate the natural stretch of the belt on start-up and also have enough travel to allow belt tension adjustments after the belt has stretched during service.
True
This type of belt conveyor take-up uses a counterweight design of some type and must provide for sufficient travel to handle any length changes in the belt.
Automatic gravity take-ups
These include vertical gravity and horizontal carriage take-ups.
What are three things that a cause a change in the conveyor belt length that an automatic belt take-up must be able to compensate for?
- start-up stretch
- load variation stretch
- weather changes (expansion and contraction)
This component of a belt conveyor provides a surplus of belt material in the event of repairs to and replacement of splices.
The belt take-up
This is the preferred style of conveyor belt take-up.
Veritical gravity take-ups
These are usually located close to the drive pulley on the return side.
On conveyor belts, what are two locations that vertical gravity take-ups are mounted and which one is the preferred?
- Return side close to the drive ⟶ preferred
- Any place along the belt return side
These are usually used on conveyors over 100’ in length.
Which belt conveyor bend profile would be used where the conveyor bends upwards?
Concave bend
A concave bend will have an angle less than 180º
Which belt conveyor bend profile would be used where the conveyor bends downward?
Convex bend
A convex bend will have an angle greater than 180º
As it pertains to belt conveyors, a convex bend in the framed will be ____ (less/greater) than 180º.
Greater than 180º
As it pertains to belt conveyors, a concave bend in the frame will be ____ (less/greater) than 180º.
Less than 180º
This type of belt conveyor take-up is used where there is insuffiecient space to allow for a gravity take-up.
A horiztonal carriage take-up
With this type of belt conveyor take-up, the counterweight or tensioning device is attached to a carriage via cables and sheaves and may be located above or below the floow or outside of the conveyor building.
Horizontal carriage take-up
Care must be taken to ensure that the carriage wheels and track are free of material and debris and that all cables sit correctly on their sheeves.
On belt conveyors, what precautions need to be taken with horizontal carriage take-ups?
Ensure that the weight is free to move
This movement is what creates the automatic portion of the take-up.
If debris or material, or the cables fail to sit properly in the sheeves, the weight could become bound, which will prevent it from properly applying weight to the belt.
True or false: On belt conveyors, screw take-ups are part of the head pulley arrangement.
False
They are part of the tail pulley arrangement.
On belt conveyors, this type of belt take-up is usually found on short conveyors and requires manual adjustment of the tension.
Screw take-ups
These are also known as threaded take-ups.
On belt conveyors, the type of take-up is also known as a threaded take-up.
Screw take-ups
These can be easily over-tensioned.
On belt conveyors, what issues can arise if threaded take-ups are over tensioned on lighter belts?
The splice could be strained and fail.
Adjust both screws the same amount to ensure proper belt tracking.
On belt conveyors, what issues can arise if threaded take-ups are over tensioned on larger belts?
Tail shaft and bearing failure.
Adjust both screws the same amount to ensure proper belt tracking.
What are the three main components of a conveyor belt?
- top cover
- bottom cover
- caracss
This component of a conveyor belt contains and protect the belt carcass from abrasion, wear, corrosion and deterioration.
The top and bottom covers
The top cover is usually thicker than the bottom cover to resist abrasion and gouging from the material being coveyed.
- On a conveyor belt, which cover is usually thicker?
- Why is this?
- the top cover
- to resist abrasion and gouging from the material being coveyed
The bottom cover usually has to provide wearing surface against the pulleys and idlers.
On a conveyor belt, this type of surface finish on the belt would be selected to prevent material from sticking to the belt surface.
A smooth finish
This would be selected for materials such as coal or cement.
On a conveyor belt, this type of surface finish on the belt would be selected to increase friction to prevent material slippage.
A rough finish
This would be selected for grain handling.
On a conveyor belt, this type of surface finish on the belt would be selected if there were wet conditions or materials having a high water content causes material slippage.
A chevron or raised V.
This increases the angle of incline.
This would include gravel or sewage plants.
What are four common types of conveyor belt carasses?
- solid woven
- reduced-ply
- multiple-ply
- steel cord
This component of a conveyor belt is the portion of the belt that provides the strength and tension.
The carcass
Which is made up of the plies.
This type of conveyor belt carcass consists of a single ply of solid woven fabric, which has an interlocking weave that helps to prevent ply separation.
Solid woven carcass
This type of conveyor belt carcass either has fewer plies than a regular mutli-ply belt or has a special weave, with the plies having wider separation between each layer and extending to the edge of the belt.
Reduced ply carcass
These belts usually have a raw edge, which makes them cheaper to produce and more suitable for smaller diameter drums.
This type of conveyor belt carcass usually has a raw edge, which makes it cheaper to produce and more suitable for smaller diameter drums.
Reduced ply carcass
Because these are not a standard construction, they have different load ratings to those of similar sized multi-ply belts.
On belt conveyors, with a multi-ply belt, what determines the strength, load and tension?
The number and type of fabric used to make up the ply layers.
The carcass is essentially the sum of the plies.
Standard conveyor belts are usually constructed from no more than eight ply layers.
True or false: Standard conveyor belts are usually constructed from no more than six ply layers.
False
Standard conveyor belts are usually constructed from no more than eight ply layers.
This component of a multi-ply conveyor belt is designed to carry the material and protect the carcass from abrasion.
The top cover
This carries none of the tension or strength of the belt.
True or false: On a multi-ply conveyor belt, the top cover carries a small portion of the tension or strength of the belt.
False
It carries none of the tension or strength of the belt.
This component of a multi-ply conveyor belt is the strength portion of the belt, and is made up of a series of plies.
The carcass
This component of a multi-ply coneyor belt is a single layer of fabric that provides load support, strength and tension.
A ply
These make up the carcass.
This component of a multi-ply conveyor belt is the yarns in the fabric that provide the tension strength of the fabric.
The wraps
This component of a multi-ply conveyor belt is the transverse yarns that runs perpendicular to the wrap yarns.
The fill
The wrap yarns run the length of the belt.
The fill provides the support and strength to hold the fasteners.
Which component of a multi-ply conveyor belt provides the support and strength to hold the fasteners?
The fill
The fill runs the width of the belt.
The fill runs perpendicular to the wrap yarns.
This component of a multi-ply conveyor belt is a rubber adhesive compound that binds the plies together.
The friction
This component of a multi-ply coneyor belt is an extra layer of rubber compound that protects against ply separation.
The skim coat
This component of a multi-ply conveyor belt is an open mesh to reinforce against longitudinal breaking under impact.
Breaker fabric
An option is to use breaker ply where the belt loading area features impacting.
This component of a multi-ply coneyor belt is usually a thinner layer of rubber than the top cover to provide a wearing surface against the pulleys and the idlers.
The bottom or pulley cover
What is another name for the bottom cover of a multi-ply conveyor belt?
The pulley cover
These are usually thinner than the top cover.
This type of conveyor belt carcass consists of steel cables running the length of the belt embedded between the top and bottom covers.
Steel cord carcass
Which type of conveyor belt carcass would be selected if the belt must operate at high tension with very little stretch and where limited take-up room is available.
Steel cord carcass
These are considered the strongest belting.
Some steel cord carcass conveyor belts may have a fabric reinforcing layer above and below the cable strands. Why is this?
To provide some transverse reinforcing
Which conveyor belt carcass is considered the strongest?
Steel corded
How are conveyor belts rated?
In P.I.W
Pounds per inch width
This is the load and tension carrying capability of the belt.
On belt conveyors, what is splicing?
The process of joining the two ends of the belt together
What are three common methods for splicing conveyor belts together?
- mechanical
- cold self-vulcanizing
- hot vulcanizing
What is the most important requirement when joining a conveyor belt with a mechancial splice?
That both ends of the belt be cut square
Failure to do this results in tracking problems.
What issues are caused when both ends of a conveyor belt being mechanically spliced are not cut square?
Tracking issues
This is an issue with mechanical splicing.
What is the main advantage of mechanical splices on conveyor belts?
Quick and easy to install.
This reduces equipment downtime.
What are the three disadvantages of mechanically splicing a conveyor belt?
- reduced belt strength
- cannot be used with metal detectors
- product may fall through the gap between the two edges of splice
This type of conveyor belt splice uses a variety of glues and fillers specifically designed for each belt type.
Cold self-splicing
Very small belts are sometimes called “tapes”.
What is the most important aspect to cold self-splicing a conveyor belt?
To ensure that the compounds have been properly mixed and belt ends properly prepared.
Which type of conveyor belt splicing method is able to achieve up to 90% belt strength?
Hot vulcainzed splicing
Some books that this method approaches close to 100% belt strength.
This method of conveyor belt splicing is the strongest and most preferred.
Hot vulcanizing splicing
This method also requires specialized equipment in the form of belt cookers to cure the splice.
What is the splice bias angle required when completing a hot vulcanized splice on a conveyor belt 24” or less?
45º
What is the splice bias angle required when completing a hot vulcainzed splice on a conveyor belt over 24” in width?
60º
What will happen to a hot vulcanized conveyor belt splice if the splicing is not square?
The belt will track off before moving back into place
What does build up on the pulleys of belt conveyor affect?
Tracking of the belt
This conveyor belt splicing process requires the belt to be cooked for a time under pressure.
Hot vulcanized splicing.
What effect does the sulphur percentage have on the strength of a hot vulcanized conveyor belt splice?
% sulphur ↑ = splice strength ↑
True or false: Steel cord belts must be hot vulcanized when splicing together and may be susceptible to longitudinal tearing.
True
How must steel cord conveyor belts be spliced together?
With hot vulcanized splicing
These belts are susceptable to longitudinal tears.
This type of conveyor belt mechanical splice can be used to repair sections of the belt that have become damaged or to repair small tears and slits.
Bolted solid plate type
On a belt conveyor, what determines the minimum pulley diameter?
The thickness of the belt
This is determined by the type of belt and number of plies.
What happens when a conveyor belt is pulled over a pulley that is too small for the thickness of the belt?
Excessive bending stresses
The radius is too small, resulting in excessive bending stresses.
This component of belt conveyor pulleys is a rubber based compound that is used to increase the coefficient of friction between the belt and the pulley.
Lagging
This is used on lagged drive pulleys.
On a belt conveyor, which pulley would normally have lagging on it?
The drive pulley
This helps to increase the coefficient of friction between the drive pulley and the belt.
This belt conveyor pulley accessory allows the belt to be driven with a lower belt tension and reduces the possibility of belt slippage due to overloading and wet conditions.
Lagged drive pulleys
This belt conveyor accessory allows pulleys to operate in wet conditions and is usually grooved to allow for the drainage of any accumulated liquid.
Lagged drive pulleys
What is side lagging on belt conveyors?
Using pre-formed vulcanized plates that can be slid out without removing the pulley or belts.
On belt conveyors, what is the main advantage of side lagging pulleys?
The lagging can be replaced without having to remove the conveyor belt
What type of pulley would be used on a belt conveyor with normal fabric ply belts?
Smooth pulleys
These are standard steel drums without the lagging.
What type of pulley would be used on a belt conveyor with high-tension and steel cored belts?
Smooth pulleys
Due to the extreme tension requirements, the pulleys are specially engineered.
This type of belt conveyor prevents buildup of material between the pulley and the belt.
Self-cleaning pulleys
These are also called wing pulleys.
The debris falls between the wings and is directed to the side by the conical shape of the hub.
Which type of belt conveyor pulley has wings and a conical shaped hub?
Self-cleaning pulleys
These are also known as wing pulleys.
On a belt conveyor system, what is a wing pulley?
The same as a self-cleaning pulley
On belt conveyors, why are self-cleaning pulleys usually limited to low-speed operations?
Intermittent contact and noise.
Due to the limited surface area of the pulley.
This type of belt conveyor pulley has a larger diameter in the centre than at the ends.
Crowned pulleys
These are used to keep the belt centred on the pulley.
This pulley is used on belt conveyor systems to keep the belt centred on the pulley.
Crowned pulleys
The standard crown is 1/8” per foor of pulley face width.
True or false: On belt conveyors with crowned pulleys, the standard crown is 1/4” per foot of pulley face width.
False
It is 1/8” per foor of pulley face width.
True or false: For crown pulleys to be effective on belt conveyors, the belt must have a long unsupported approach to the pulley.
True
This makes them ineffective on trough conveyor head pulleys.
On a belt conveyor, crown pulleys are helpful when used in what three pulley locations?
- bend pulleys
- take-up pulleys
- tail pulleys
This is due to the requirement for a long unsupported approach to the crown pulley.
In what three types of applications should crown pulleys never be used?
- high-tension steel cable belts
- snubbed drive pulleys
- multiple drives
On a belt conveyor system, this is usually the largest diameter pulley and is located at the discharge end.
The head pulley
Unless a tripper is used.
Some conveyors are designed so that the head pulley is also the drive pulley, so they are sometimes called the same thing.
On a belt conveyor system, this pulley returns the belt to the material carrying side and is at the opposite end of the belt from that of the head pulley.
The tail pulley
True or false: Material loading on belt conveyors is usually done close to the tail pulley section.
True
True or false: On small or short conveyor systems the head pulley may also be used to tension the belt by means of a screw take-up.
False
The screw take-up would be located on the tail pulley.
On belt conveyor systems, this pulley is used to increase the arc of contact on the drive pulley.
Snub pulleys
Normal contact is 180º, but can be increased to maximum of 240º.
- On a belt conveyor, what is the normal arc of contact on the drive pulley?
- What is the maximum arc of contact that can be achieved with a snub pulley?
- 180º
- 240º
These belts usually have a raw edge, which makes them cheaper to produce and more suitable for smaller diameter drums.
Reduced ply belts
This component of a multi-ply conveyor belt runs perpendicular to the wrap yarns.
The fill
The fill runs the width of the belt.
On a belt conveyor, this pulley is used to change the direction of a belt, usually to allow for the installation of a gravity take-up system.
Bend pulleys
A belt conveyor can be driven at either end or at any point along the ________ side of the belt.
return
True or false: A belt conveyor driving effort can be applied to more than one pulley and may be applied at two or more points along the conveyor.
True
The is employed in long, relatively level conveyors.
The drive arrangement of a belt conveyor is dependant upon what three factors?
- type of material conveyed
- environment
- performance requirements
On a belt conveyor, where can single pulley drives be located?
At either the head or tail pulley
These are the simplest and most common type of pulley drive.
On a belt conveyor system, what two things determine the amount of power that can be applied to the belt?
- the coefficient of friction of the pulley surfaces
- the arc of contact
A larger arc of contact = greater power applied to the belt.
On belt conveyor systems, this type of drive system uses one motor to drive two pulleys, either through a gear or chain drive between the two drive pulleys.
A tandem drive
On a belt conveyor system, this type of drive system uses one motor for each of two drive pulleys.
Dual drive systems
On a belt conveyor system with a dual drive arrangement, what are two ways of regulating the load distribution and speed between the two pulleys?
- wound rotor type motor
- fluid couplings (scoop-controlled)
This is on the second motor (slave).
On a belt conveyor system, this type of drive system has the conveyor being driven from more than one spot on the conveyor with individual pulleys, each with its own separate drive motor.
Multiple drive system
On a belt conveyor, what are the two main advantages of a multiple drive arrangment?
- Reduces belt tension
- Helps to prevent the motors from overloading
What type of belt conveyor drive system would be selected for very long conveyor systems handling large volumes of material, such as in the mining industry?
Mutliple drive system
What are two basic types of idlers found on belt conveyor systems?
- Carrying idlers → these support the load side of the belt
- Return idlers → these support the return side of the belt
The carrying idlers may be troughing or flat, while the return idlers are generally flat.
This type of belt conveyor idlers support the loaded side of the belt and may be troughing or flat.
Carrying idlers
This type of belt conveyor idler supports the return side of the conveyor belt and are generally flat.
Returning idlers
On belt conveyors, this is the most widely used type of carrying idlers.
Troughing idlers
On belt conveyors, what are the two benefits of the trough shape on troughing idlers?
- To increase belt carrying capacity
- Reduce material spillage
This type of belt conveyor carrying idlers are made up of three separate rollers, with the two outside rollers inclined and the centre roller horizontal to the conveyor bed.
Frame mounted troughing idlers
What are the three standard angles found on belt conveyor frame-mounted troughing idlers?
20º, 35º, and 40º
On belt conveyors, some frame-mounted troughing idlers have the centre roller mounted ahead of the centre line of the angled rollers. What is the advantage of this arrangement?
It allows the belt to sit lower in the frame, reducing material load height
These are known as offset type troughing idlers
On a belt conveyor system, what is an offset type troughing idler?
An idler where the centre roller is mounted ahead of the angled rollers.
This allows the belt to sit lower, reducing the material load height
True or false: On a belt conveyor system, properly installed troughing idlers help to maintain belt tracking.
True
The idlers should be installed square to the frame and parallel to each other.
On a belt conveyor system, the troughing idlers are sometimes tilted 2º in the direction of belt travel. Why is this done?
To improve belt tracking
By creating a “self-centering” effect. This angle forces the belt to align towards the center of the idler due to the natural tendency of the belt to follow the path of least resistance.
On a belt conveyor, how does a 2º tilt in the frame of troughing idlers help with belt tracking?
By creating a “self-centering” effect.
When the belt travels up one of the angled rollers, more of the belt is on that roller. This results in increased weight on that section of belt, which pushes it back to the centre.
On a belt conveyor, what effect does a greater than 2º tilt in the frame of troughing idler have?
It will result in excess wear in the belt and idlers.
On belt conveyors, this type of idler is made up of a series of rollers mounted on a flexible steel cable which is attached to the side of the conveyor.
Suspended (catenary) idler
This type of belt conveyor idler is attached with a quick release mechanism that allows it to be removed and replaced quickly.
Suspended (catenary) idlers
This type of belt conveyor idler swings freely and is not adversely affected by conveyor bed misalignment.
Suspended (catenary) idlers
On a belt conveyer, what is a catenary idler?
The same as a suspended idler
On a belt conveyor, this type of idler is installed just before the head pulley and just after the tail pulley on troughed conveyors and are used to gradually trough or flatten the belt.
Transition idlers
These belts gradually trough or flatten the belt.
The distance between the idlers and total transition distance is determined by belt tension, belt strength, and carcass composition.
On a troughed belt conveyor, a transition pulley allows the belt to flatten out before going over the 1.________ pulley and to form a trough shape after going over the 2.________ pulley.
- head pulley
- tail pulley
Flattening the belt before going over the head pulley reduces belt edge stretching.
On conveyor belts, this type of idler can pivot around a centre point on the frame, and has side guide rollers attached to the outer edge of the inclined rollers.
Self-aligning (training) idlers
These idlers can correct small tracking problems, but does not correct severe misalignment problems.
On belt conveyors, what is another name for training idlers?
Self-aligning idlers
These idlers are capable of correcting small tracking problems along the length of the conveyor.
This type of belt conveyor idler works by pivoting when the belt climbs the inclined roller, where it contacts the side guide. The causes the side in contact with the belt to move forward in the direction of belt travel, resulting in a forward cant that directs the belt back towards the centre of the conveyor.
Training idlers
These are also known as self-aligning idlers.
These idlers are capable of correcting small tracking problems along the length of the conveyor.
When installing self-aligning idlers on a belt conveyor system, how should the side guide rollers be orientated in relation to belt travel?
The side guide rollers should facing towards the tail pulley
The side roller should be facing the opposite direction of belt travel.
True or false: Training idlers are capable of correcting severe misalignment problems on belt conveyors.
False
They can correct small tracking problems, but not severe misalignment.
On a belt conveyor, this type of idler is installed at various point along the conveyor where objects close to the belt may be damaged if the belt runs off.
Fixed side guides
These are also known as guidlers.
On a belt conveyor, what is a guidler?
The same as a fixed side guide idler
On a belt conveyor, this component is used to protect the frame (or other objects) from belt damage due to the belt running off to one side.
Fixed side guides
True or false: On a belt conveyor, fixed side guides do not correct for a misaligned belt.
True
They only prevent damage to the framework of the conveyor, the belt or other objects caused by the belt running off to one side.
On a belt conveyor, this type of idler is used where spillage does not pose a problem and the ability to convey a wide variety of products is the main concern.
Flat belt idlers
On a belt conveyor, this type of idler is installed directly under the loading point of the conveyor to protect the belt from impact damage caused by loading of the material.
Impact idlers
These are manufactured from a series of solid rubber rings or pneumatic rubber rollers.
On belt conveyor idlers, this type of idler is made from a series of solid rubber rings or pneumatic rubber rollers.
Impact idlers
These materials allow the belt to deflect slightly, absorbing impact.
On belt conveyors, what are the three standard angles for impact idlers?
20º, 35º, and 40º
This is done to match the standard troughing idler angles.
On belt conveyors, what effect does belt sag have on the power requirements of the conveyor system?
It increases the power requirements.
This is due to wasted power used by the belt to climb over the rollers.
True or false: For impact idlers to be effective on a belt conveyor system, the idlers should be installed as close together as possible to prevent belt sag.
True
On a belt conveyor system, this component allows the belt to run smoothly over a series of low-friction impact absorbing rubber slats that are mounted on a frame.
Slider belt cradles
These are used to reduce impact damage at loading zones.
On a belt conveyor, this component is used to support the belt on the return or slack side of the belt and is usually attached to the underside of the frame.
Return idlers
This type of belt conveyor return idler has slotted bolt holes to allow adjustment of the return idler to aid in the tracking of the belt and have a centre slot which the idler axle sits.
Flat return idlers
These are like the flat or straight carrying idlers.
This type of belt conveyor return idler can be replaced without removal or adjustment of the idler mounting brackets.
Flat return idlers
The design of the centre slot in the mounting bracket allows the idler to be easily removed.
This type of belt conveyor return idler is used where sticky or corrosive materials are present, but the belt must travel in one direction only.
Spiral type return idlers
Their unique design helps maintain belt alingment and prevent material buildup.
This type of belt conveyor return idler is used where sticky and corrosive materials are present, but the belt can travel in both directions.
Rubber disc type return idlers.
This is compared to a spiral type, which allows belt travel in only one direction.
True or false: On a belt conveyor, when tilting troughing idlers 2º to aid with belt tracking, the tilt is against the belt travel.
False
The 2º tilt is in the direction of belt travel.
Which type of carrying idler section can be replaced quickly and easily because it uses a quick release mechanism?
Catenary
These are also called suspended idlers.
Where does the majority of belt alignment problems occur in a belt conveyor system?
On the return side of the belt
On really long belt conveyors, this component is used to help overcome the problem of alignment problems on the return side of the belt.
Inclined return idlers
These may be made from solid steel or rubber rings.
What are the two angles found on belt conveyor inclinder return idlers?
10º and 20º
True or false: A major cause of belt tracking problems is rollers that have become jammed or stuck.
True
This is why it is important to ensure that there is minimal spillage at the loading section, as this can cause this type of failure.
On a belt conveyor, when the belt continues to track off, one method of correction is to slightly skew the idlers over in the direction of belt travel. In what direction will the belt travel when this is done?
Towards the side of first contact
If the belt contacts the roller on the left side first, the belt will travel in that direction and vic veras.
On a very long belt conveyor, when correcting belt tracking by slighly skewing the rollers in a specific direction, which rollers should be adjusted first?
The return idlers
Once a new belt has been installed into a belt conveyor, upon start-up, it must be ________, meaning it must be aligned so that it runs in the centre of the drum.
Trained
Tracking is the same thing, but after the belt has been runnng.
Trained = new belt
True or false: When training or tracking a conveyor belt, it is important to ensure that the belt tension is not loosened during the process.
True
On a belt conveyor, how is belt training completed on short belts, such as feeder belts?
By adjusting the tail pulley
This is usually done by using a screw take-up ⟶ avoid over tensioning.
True or false: Both the tail and head pulleys on belt coveyors can be adjusted to correct belt misalignment.
False
The head pulley should never be adjusted to correct belt misalignment.
On belt conveyors, what accessory can be installed on both the carrying and return side to help with belt alignment?
Self-aligning idlers
These idlers can correct small tracking problems, but does not correct severe misalignment problems.
True or false: On belt conveyors, self-aligning idlers are capable of correcting severe misalignment problems.
False
These idlers can correct small tracking problems, but does not correct severe misalignment problems.
On belt conveyors, some return idlers are manufactured with two rollers forming a 10º or 20º V. Why is this done?
To help centre the belt
On a belt conveyor, what two issues are created by material build up on the pulley faces?
- Belt tracking
- Belt tension (over tension)
On a belt conveyor, what effect does material build-up on the pulley have on the carcass of the belt?
Damages it
This is due to the high pressures exerted on it by increasing the tension on the belt.
On a belt conveyor, the type of belt scraper used on the belt is determined by what two things?
- The material being conveyed
- The type of splice in the belt
True or false: On a belt conveyor, many different types of belt scrapers may be used on one belt if the materail is wet and sticky.
True
On a belt conveyor, what is the most common type of scraper?
V plow scraper
These consist of a metal from on which an adjustable rubber skirt is mounted.
On belt conveyors, where are V plows usually located?
Before the tail pulley
This is to prevent material from becoming trapped between the belt and pulley face.
What two types of belt conveyor cleaners are employed to clean the belt as it passes over the head and/or snub pulleys?
- Rubber strips attached to a board
- Blade cleaners
True or false: Conveyor belt cleaners that are used to clean the head and/or snub pulley should be mounted at or just below the centreline of the pulley.
True
What are two ways that the conveyor belt cleaners used to clean the head and/or snub pulley can be held against the pulley?
- With a counterweight ⟶ rubber strips
- With a torsion arm ⟶ blade cleaners
True or false: On belt conveyors with blade cleaners, the blades can be made out of urethane, mild steel, stainless stell and tungsten.
True
On belt conveyors, this type of cleaner is a revolving brush, rotated by an electric motor at 400 rpm in the opposite direction of belt travel. What kind of materials is this cleaner good for?
Dry fines
This type of belt conveyor cleaner consists of a steel wire, drawn tight across the belt. What types of splices is this cleaner not suitable to be used with?
Mechanical splices
As it relates to belt conveyors, what is tramp iron?
Undesirable pieces of ferrous metal that has made its way into the conveyed material.
These can be removed with magnetic separation.
On belt conveyors, what are two ways to remove tramp iron?
- Magentic pulleys
- Suspended magnets
On belt conveyors, this type of ferrous metal separation method holds the magnetic material against the belt as it passes over the head pulley where the magnetic field is broken after the main discharge and the tramp metal falls into a separate chute.
Magnetic pulley
Sometimes referred to as a magnetic head pulley
On belt conveyors, this type of ferrous metal separation method uses a small separate belt with a magnetic head pulley positioned above the laod at the discharge point on the main belt.
Magnetic pulley on separate belt
The tramp iron is lifted off the main belt to the smaller belt where it is discharged into a collector bin.
On belt conveyors, this type of magentic separation method uses a magnet located just above the discharge tragectory.
Suspended magnets
Removing tramp iron from the magnet is accomplished by switching off the power after the magnet has been positioned over a suitable container.
On belt conveyors, what is used to separate non-ferrous metals from the material being conveyed?
Metal detectors
These, along with manpower, remove non-ferrous metals from the material.
A belt conveyor operating on a ________ (incline/decline) usually requires a brake system to prevent the conveyor from running forward after the power is shut off.
decline
This is also good practise to ensure the conveyor doesn’t runaway during operation.
How are brakes operated on belt conveyors?
Solenoid released, spring operated
These brakes will engage when power is removed.
- Where are brakes usually located on smaller belt conveyors?
- Where are they located on large ones?
- On the high-speed shaft of the speed reducer
- The drive pulley ⟶ it is extended, allowing the brake to be attached
These are usually disc or drum type brakes.
A belt conveyor operating on a ________ (incline/decline) usually requires a backstop to prevent rollback in the event of power failure.
incline
These are usually sprag or over-running clutches.
What are two types of clutches used as backstops on belt conveyors?
- sprag clutches
- over-running clutches
What are two locations where backstops are installed on belt conveyors?
- On the drive pulley shaft
- On the high-speed reducer shaft
These are the same locations as brakes, and are selected much in the same way ⟶ based on the size of the belt system
On a belt conveyor, can a worm gear be used as a backstop?
Yes, but only if it has a gear ratio ≤ 30:1
On a belt conveyor, what could be the cause of a particular section of belt running out to one side at all points along the conveyor?
The belt splice is out of square
Resplice the belt with square ends.
What are three things that can be done to a belt conveyor system that is experiencing slippage on the drive pulley?
- Increase belt tension
- Lag drive pulley
- Increase arc of contact with a snub pulley
True or false: Slippage is a cause of severe wear on the pulley side of a conveyor belt.
True
On a belt conveyor, what effect does increasing the idler spacing have on the idler load?
Idler spacing ↑ = Idler load ↑
The less idlers there are in one area, the greater the load on each individual idler.
On belt conveyors, this system of idler spacing has idlers spaced farther apart where the belt tension is high and closer together where the belt tension is low.
Graduated idler spacing
This is to reduce belt sagging, which wastes power.
These values do not includer idler spacing at the loaded zone ⟶ much closer spaceing is employed here.
True or false: A thorough chain conveyor inspection requires the removal of all the conveyed material.
True
This component of a belt conveyer ensures that there aren’t unloaded or overloaded spots along the belt, which can result in spillage when excess material falls from the edge of the belt.
Feeders
On a belt conveyor, what is the difference between tracking and training a belt?
Training ⟶ completed on a new belt at start-up
Tracking ⟶ done to belt while it is running to fix tracking issues
These are both done to align the belt.
