433A Conveyor Systems 3 — Questions and Answers
Question 1: What is the function of a backstop on an inclined belt conveyor?
- To stop the belt from tracking too far
- To prevent the loaded belt from running backward if the drive loses power, which could cause material runback and drive damage (Correct answer)
- To back up the belt speed controller
- To limit the maximum incline angle
Correct answer: To prevent the loaded belt from running backward if the drive loses power, which could cause material runback and drive damage
A backstop (holdback) is a one-way clutch or brake on the drive shaft that allows rotation in the forward direction but locks against reverse rotation. On inclined conveyors, it prevents the loaded belt from running backward if the motor stops or loses power.
Question 2: What is a vibrating conveyor and what type of material does it handle best?
- A belt conveyor that vibrates
- A conveyor that moves material along a trough using controlled vibration, ideal for hot, abrasive, or screening applications (Correct answer)
- A conveyor used to shake loose material
- A malfunctioning conveyor
Correct answer: A conveyor that moves material along a trough using controlled vibration, ideal for hot, abrasive, or screening applications
A vibrating conveyor uses an oscillating trough driven by an eccentric or electromagnetic vibrator to move material in short, repeated tosses. It is excellent for handling hot materials, performing screening operations, and conveying abrasive products that would damage belts.
Question 3: What is the correct method for belt splicing using a vulcanized splice?
- Simply glue the belt ends together
- Strip back the belt cover and fabric plies, assemble stepped or finger joints with bonding cement, then cure under heat and pressure in a vulcanizing press (Correct answer)
- Staple the belt ends together
- Melt the belt ends with a torch
Correct answer: Strip back the belt cover and fabric plies, assemble stepped or finger joints with bonding cement, then cure under heat and pressure in a vulcanizing press
A vulcanized splice involves carefully stripping back the belt covers and fabric plies to create stepped or finger joints, applying bonding cement and uncured rubber between layers, then curing the assembly under controlled heat and pressure in a vulcanizing press to create a permanent, strong joint.
Question 4: What is the purpose of return idlers on a belt conveyor?
- To return spilled material to the belt
- To support the empty belt on its return run back to the tail pulley, preventing excessive sag and belt damage (Correct answer)
- To increase belt speed on the return side
- To clean the underside of the belt
Correct answer: To support the empty belt on its return run back to the tail pulley, preventing excessive sag and belt damage
Return idlers support the belt on the lower (return) strand as it travels back to the tail pulley after discharging material. They prevent excessive belt sag, reduce belt flapping and wear, and are typically spaced farther apart than carrying idlers since the belt is unloaded.
Question 5: What is a drag chain conveyor (en-masse conveyor) used for?
- Dragging heavy equipment
- Moving bulk material through an enclosed housing using a chain with flights that drag material along the bottom of the trough (Correct answer)
- A conveyor pulled by a vehicle
- A chain used for conveyor maintenance
Correct answer: Moving bulk material through an enclosed housing using a chain with flights that drag material along the bottom of the trough
A drag chain (en-masse) conveyor uses a single or double chain with attached flights (crossbars) inside an enclosed trough. The flights drag bulk material along the bottom of the trough. The enclosed design contains dust and handles multiple discharge points.
Question 6: What is the purpose of a belt scale (weighing system) on a conveyor?
- To weigh the belt itself
- To continuously measure the weight of material on the belt and calculate throughput (tons per hour) for process control and inventory tracking (Correct answer)
- To check belt tension
- To measure belt thickness
Correct answer: To continuously measure the weight of material on the belt and calculate throughput (tons per hour) for process control and inventory tracking
A belt scale uses load cells under a weigh idler to measure the weight of material on the belt per unit length. Combined with belt speed measurement, it calculates mass flow rate (tons/hour) for production monitoring, batch control, and inventory management.
433A Conveyor Systems 3
What is the function of a backstop on an inclined belt conveyor?