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Fourth Year Millwright > Conveyors > Flashcards

Flashcards in Conveyors Deck (119)
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1

What are the key components of conveyors?

Belts,idlers, pulleys,take ups and tensioning device, loading and unloading systems

2

What can be done to adapt to ground profile?

Bends in the frame, and the use of bend pulleys and idlers. Convex bends with high point in middle and bending down (like a flat bed trailer) and concave bending upward

3

What is a tripper?

It is a device that can discharge material from either selected points, or any point along the length of the conveyor. It's purpose is for stockpiling material at several points along the conveyor. Some can rotate and unload on both sides

4

What is a feeder?

They are sometimes installed before the main conveyor, to provide a constant flow of material, and avoid overloaded spots which causes spillage. They are usually flat, and wider than conveyor belts

5

Where is the highest wear point found on a conveyor?

Usually the loading point. This is where most of the impact, and abrasion happen.

6

What is the best way to load a belt?

Have the material feed from the loading chute at the same speed, and in the same direction of the belt. It should also be loaded in the middle of the belt

7

What is a transition conveyor?

It is similar to a feeder, the material is properly centred to eliminate tracking problems, and the impact is reduced due to there diction in transfer height.

8

What is a side loader chute?

When the angles of the conveyor are changed, it can be dumped in a chute that takes it to another conveyor. Baffles are installed in the chute to slow the material and direct it to the center of the belt.

9

What things should be accomplished when designing a chute?

Material must be centred, flow in the direction of travel of the belt, reduce impact and abrasion of the belt, steep enough to avoid wet material from sticking inside, have chute liners if the material is abrasive

10

What is a rock box?

Located at the discharge end of the head pulley. The box fills with initial flow, then spills the material down the chute. The material absorbs most of the impact and abrasion.

11

What are Grizzlies?

It allows fine material to filter through them. The fine material acts as a cushion for the bigger pieces, reducing wear on the belt

12

What are skirt boards?

They extend off the bottom of the chute along the conveyor, to confine the material and prevent spillage. The mimumum clearance is 1" from bottom of skirt board to the belt. The rubber skirting at the bottom of the skirt board is to never be old belt material, it is too hard

13

What is a belt take up?

A tensioning device, usually found at the tail pulley

14

What is an automatic gravity take up?

Uses a counterweight design to tension belt. Needs to have sufficient travel to handle length changes from: startup, temperature changes, load variation. Same as belt system in shop

15

If there is not enough headroom for vertical gravity take up, what can be used?

Horizontal gravity take up. The back carriage is on wheels, that are attached to some pulleys and a weight. The disadvantage is the carriage wheels and track get dirty and material spilled on it

16

What is a screw take ups?

They are part of the tail pulley, found on short conveyors, and must be manually adjusted

17

What are the three main sections of a belt construction?

Top cover (thicker than bottom)
Carcass
Bottom cover

18

What are the three surface finishes for belts?

Smooth- to prevent material sticking to it
Rough- increase friction, prevent material slippage
Chevron or raised v- increases the angle of incline for wet conditions, or material having high water content

19

What are the four types of carcasses?

Solid woven, reduced ply, multiple ply, steel cord?

20

Describe a solid woven carcass

A single ply of solid woven fabric which has an interlocking weave

21

What is the purpose of the carcass?

It provides the strength, tension, and transmits the power of the belt

22

What is a reduced ply carcass?

Fewer plies than multiple ply. Plies have a wider separation between each layer. Due to fact they are not a standard construction, they have different load ratings than similar sized multi layers

23

What is a multiple ply?

At least 3 layers, but no more than 8. It has more flexibility

24

What is friction, in regards to belt construction?

It is a rubber adhesive compound that binds the plies together

25

What is breaker fabric?

It is an open mesh to reinforce against longitudinal breaking under impact. They run across the short direction of the belt

26

Describe steel cord belts?

Can be run in high tension, with little stretch. These belts must be hot vulcanized, and they are prone to longitudinal tears

27

What are the three types of joining methods for belts?

Mechanical, cold self vulcanizing, and hot vulcanizing

28

What are the different types of mechanical splices?

Riveted solid plate, bolted double plate, bolted hinge plate, riveted hinge plate, alligator clips. All of these splice methods must have both ends of the belt cut square, or the belt will track to the sides at the splice.

29

Which mechanical joining method can be used to repair tears in belts?

The bolted plate, or bolted double plate

30

What is the strongest most preferred method of splicing belts?

Hot vulcanized, and it can achieve 90% belt strength.