Vibratory conveyor / Oscillating Conveyor

A vibratory conveyor essentially consists of an open or closed trough or pipe, generally horizontal but not always so, and which is elastically supported on a base structure or suspended from an overhead structure by springs. The trough or pipe is caused to oscillate at high frequency and small amplitude by an appropriate drive mechanism. Vibratory conveyors are commonly employed in industry to carry a wide variety of particulate and granular types of bulk materials. The fundamental action of the vibrating troughs on the bulk material loaded on it is to throw the particles upward in the forward direction so that the material performs series of short hopping movement and propagates at a certain speed.

Oscillating conveyors are utilized to convey sand or other granular particles at a desired rate. The conveyor is generally placed under a vibrating shakeout or a grid to eliminate direct handling of hot sand by the belt conveyor. In the process of reciprocation, the oscillating conveyor cools the hot sand to some extent which increases the life of the return sand conveyor belt.

An important characteristic of vibratory conveyor is the ease with which the flow rate of the conveyed material can be controlled by adjusting the amplitude and or frequency of the vibration. This particular aspects of such conveyor has led to the wide spread application of vibrating trough as feeders employed to supply material in controlled amount to various machines. When the trough is replaced by a screen, the vibratory conveyor may serve as vibrating screen, which has wide application in various industries. A distinction must be made between feeders and conveyors. A feeder is used as a discharge device under a storage hopper or bin and is subjected to varying head loads. A conveyor requires regulated feed rate and must not operate under varying head load conditions.

Construction details of Oscillating Conveyor:

MATERIAL HANDLING

Bases on Design features and operational characteristics, material handling equipment may be broadly classified as:

Hoisting Equipment’s:

It constitute a group of equipment which are employed mainly for lifting or lowering of unit load or piece goods in batches. This group of equipment’s can be further sub classified into:

1. Pure Hoisting Machineries

• Jack
• Winches
• Hand Hoists
• Pulley Blocks

2. Cranes

• EOT Crane
• Jib Crane
• Cantilever Crane

3. Elevators

• Lift
• Bucket Elevators

Conveying Equipment’s:

It comprises of a number of equipment which are employed for handling principally bulk load (occasionally piece goods or unit load may also be handled) in continuous flow. Such machines do not have separate lifting or lowering gear. This group of equipment also can have further sub classifications as:

1. Belt Conveyor

2. Hydraulic Conveyor

3. Pneumatic Conveyor

4. Apron Conveyor

5. Screw Conveyor

6. Flight Conveyor

Surface/ Overhead Equipment’s:

These are the group of equipment’s which are employed for handling unit load or bulk load in batches on a horizontal surface. This group of equipment may be further sub classified into:

1. Truck and Lorries

2. Railway Cars and Wagons

3. Fork Lifts

4. Overhead mono-rail / Equipment

5. Scrapers and Skidders

Types of Material Handling Equipment Loads:

It usually classified into:

1. Unit Load

2. Bulk Load

Unit Load:

Unit loads are those which are counted by numbers or units. A component of a machine, a complete machine, a structural element, a beam, a girder, building block are some examples of unit load.

Sometimes certain quantities of free flowing materials can be placed in a container and can be handled as unit load. Hoisting equipment are primarily used for handling unit load. Unit loads are usually specified by it’s weight.

Bulk Load:

When the load is in the form of particles or lumps of homogeneous materials or powder like materials, which can not be counted by numbers, it is called as “Bulk load”.

Examples are:

Sand, Cement, Coal, Mineral, Stone, Clay etc.,

A bulk material may be classified by it’s:

1. Bulk Density

2. Lump-Size

3. Flowability

4. Abrasiveness

5. Miscellaneous Characteristics

PULLEY

Pulley:

The diameters of standard pulleys are: 200, 250, 315, 400, 500, 630, 800, 1000, 1250, 1400 and 1600 mm. pulley may be straight faced or crowned. The crown serves to keep the belt centered. The height of the crown is usually 0.5% of the pulley width, but not less than 4 mm. The pulley diameter D_p depends on the number of plies of belt and may be also be determined from the formula:

D_p > K.i (mm)

Where

K = a factor depending on the number of plies (125 to 150)

i = no of plies

The compound value should be rounded off to the nearest standard size. While selecting the pulley diameter it should be ascertained that the diameter selected is larger than the minimum diameter of pulley for the particular belt selected.

The drive pulley may be lagged by rubber coating whenever necessary, to increase the coefficient of friction. The lagging thickness shall vary between 6 to 12 mm. The hardness of rubber lagging of the pulley shall be less than that of the cover rubber of the running belt.

Pulley types:

Pulleys are manufactured in a wide range of sizes, consisting of a continuous rim and two end discs fitted with hubs. In most of the conveyor pulleys intermediate stiffening discs are welded inside the rim. Other pulleys are self cleaning wing types which are used as the tail, take-up, or snub pulley where material tends to build up on the pulley face. Magnetic types of pulleys are used to remove tramp iron from the material being conveyed.

Typical welded steel pulley-Drum conveyor pulley

Spun end curve crown pulley

Spiral drum conveyor pulley

Welded steel pulley with diamond grooved lagging

Welded steel pulley with grooved Lagging

Spiral Wing Conveyor pulley

 

Power calculation for the drive unit:

The horse power required at the drive of a belt conveyor is derived from the following formula:

H.P = T_e . V

Where

T_e is the effective tension in the belt in N

V = velocity of the belt in m/s

The required effective tension T_e on the driving pulley of a belt conveyor is obtained by adding up all the resistances.