Conveyors Flashcards
What is a tripper?
A device that allows the discharge of material from either selected points or any point along the length of a conveyor
What is a feeder?
Provides a constant uniform feed of the product being transferred, onto the belt.
What are translation conveyors and
in-line chutes used for?
They are used to load material onto a belt with a minimum of spillage
What are grizzly bars used for?
They allow fine material to trickle through the bars to the belt underneath just prior to the discharge point, the fine material acts as a cushion for the larger lumps, thus reducing belt wear
How much clearance is usually recommended between skit boards and the conveyor?
About 1”
Why should you never use old conveyor belt as a skit rubber?
Old conveyor belt is often harder the a new conveyor belt and will wear itself through the new belt.
Always use a softer rubber then the belt itself
What are the two main automatic gravity take-ups?
Vertical gravity take-ups
Horizontal carriage take-ups
When would you typically use screw take-ups?
On short conveyors
What are the three main sections a belt is composed of?
Top cover
Bottom cover
Carcass
What part of a conveyor belt carries the load and tension?
The carcass
How must you splice a steel cord belt?
You must hot vulcanize this belt
In a multiple-ply conveyor belt what is the breaker fabric and where is it located?
It is an open mesh to reinforce against longitudinal breaking under impact.
It is just below the top cover
What are the 4 basic types of conveyor carcasses?
Solid woven
Reduced-ply
Multiple-ply
Steel cord
What are the three basic splicing methods for conveyor belts?
Mechanical
Cold self-vulcanizing
Hot vulcanizing
IP Question
What is the recommended belt angle for a hot vulcanized splice?
22°
What is the main purpose of a lagged drive pulley?
To increase the coefficient of friction between the belt and the pulley.
What is the purpose of a self-cleaning pulley?
It prevents the build up of material between the pulley and the belt.
Usually used on slow-speed conveyors
What is the standard crown of a crowned pulley?
1/8” per foot of pulley face width
What is the advantage of a crowned pulley?
They help to keep the belt centred on the pulley
What is a snub pulley?
Used to increase the arc of contact of the belt. From normally 180° without a snub pulley, to a maximum of 240° with a snub pulley.
What are troughing idlers?
Carriying idlers that form a trough shape to increase the belt carrying capacity and reduce material spilling
On frame mounted troughing idlers, what are the 3 standard incline in degrees for the two outside rollers?
20°
35°
45°
How much tilt do some troughing idler frames have to help maintain the belt tracking?
2° off vertical in the direction of travel
What are suspended (catenary) idlers?
Series of rollers mounted on a flexible steel cable and are attached to the side frames of the conveyor
What is the purpose of transition idlers?
They are installed just before the head pulley or just after the tail pulley on troughed conveyors. There purpose is to gradually trough or flatten the belt.
How do self-aligning (training) idlers work?
They have a side guide roller attached to the outta edge of the inclined rollers, when the belt runs off to one side it climbs the inclined roller and makes contact with the side guide roller, causing the training idler to pivot
What is the purpose of fixed
side-guides / guilders?
They are installed near objects that may be damaged if the belt runs off to one side. Belts can easily wear through the frame and other equipment.
What are impact idlers used for and what are they made of?
They’re used directly under the loading point and protect the belt from any damage due to loading impact,
They are manufactured from a series of solid rubber rings or may even be pneumatic rubber rollers
What does it mean to train a belt?
It means to train a new belt to run centred on the drum upon startup
What are the three systems used to remove metal from a conveyor belt?
Magnetic pulley
Magnetic pulley on separate belt
Suspended magnet
What 3 functions does an automatic take-up perform?
Maintains tension
Removes slack on start-up
Allows expansion and contraction of the belt due to weather conditions
What type of return idlers are used when sticky material is being transported?
Spiral rubber disc
What are the three main classes of chain conveyors?
Parallel strand
Gravity drop drives
S drives
On a gravity drop chain conveyor how does the chain maintain contact with the drive sprocket?
It uses the weight of the chain to maintain contact
What are some of the more common types of chains?
Combination chain
Pintle and H class mill chain
Drag or refuse chain
Fabricated chain
Detachable chain
Transfer chain
What is the purpose of a split hub sprocket?
It allows the sprocket to be changed without disturbing the drive arrangement or alignment
How does a continuous bucket elevator function?
The buckets are designed and spaced so that each bucket discharges over the back of the preceding one, which acts in the same way as a discharge chute
What are the two types of bucket elevators?
Continuous bucket elevator
Centrifugal discharge bucket elevator
What is the purpose of the gudgeon shaft on a screw conveyor?
The gudegeon shaft joins and supports the screw sections to
What are the two general types of roller conveyors?
Standard gravity roller conveyors
Skate wheel conveyors
For a roller conveyors, how many rollers should be in contact with the container?
The smallest number of rollers under the smallest container at anytime should be THREE
For skate wheel conveyors, what is the minimum amount of wheels there should be in contact with a package?
The smallest number of wheels under the smallest package the conveyor is expected to handle should be FIVE
In gravity rollers what part of the bearing spins?
The outer race of the bearing revolves around the fixed inner race
What is conveyor pitch?
The amount of drop per unit of length a conveyor requires in order to carry the given loads
How is the curve radius measured on roller conveyors?
The curve radius is measured to the inside face of the inside conveyor frame member
What is an advantage of the tapered roller curves?
They turn the package as it goes around the curve, thereby keeping the package aligned with the direction of travel
What are the most common ways to drive a roller conveyor?
Flat belts
V-belts
Round belts
Chains
Direct drive
What are the two most common types of chain drive systems for roller conveyors?
Continuous chain drive system
( one long belt around multiple gears. Has hold down plates and channel guides to maintain contact with top and bottoms of the gears in the middle of the chain)
Roll to roll drive system
(2 sprockets on each shaft of the roll assembly)
What are eccentric rolls used for?
To move material across a travelling chain to an end stop
What does a bottle roll look like?
They are cylindrical with one end of the roll tapered so material can ride up onto the roll
What are hourglass rolls used for?
Rolls shaped like an hourglass designed to carry cylindrical objects such as pipe or logs
What are roller conveyor spurs?
Spurs are roller or wheel conveyors used to transfer loads off of or onto belt or roller conveyors
What are the different types of spurs for roller conveyors?
Gravity roller spur
Live roller spur
What are deflectors and how are they powered?
Moveable arms or plates used to sort packages in a roller conveyor system
They are powered by hydraulic or pneumatic actuators
What are Jump rolls used for?
They are used to transfer packages across side transfer chains
What is a ball transfer table?
Location where several roller conveyors meet. Allows packages to be rolled manually from one conveyor to another over the ball transfer for sorting.
What are overload devices?
Pins used to prevent damage to the components of a roller conveyor when the conveyor jams or stalls
What are the 2 different types of pneumatic conveyors?
Negative pressure (vacuum) systems
Positive pressure systems
What are the three types of positive pressure pneumatic conveyor systems?
Low pressure
Medium pressure
High pressure
What type of compressors/blowers do low pressure conveying systems use?
Lobe or roots type blowers to supply the air pressure in the transport line
In a pneumatic conveying system. Where do you see the most wear?
The wear takes place mostly on the inside of the outside radius on pipe bends
What are the typical pressures for medium pressure pneumatic conveying systems?
15 psig - 45 psig
Why is a feeder used for? (Pneumatic)
Used to ensure material is able to enter the air stream in the pneumatic conveyor
What are the 2 sections of an air slide conveyor?
The upper section contains the material to be conveyed
The lower section is the air chamber.
The 2 sections are divided by a porous material
