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.