Construction

MERCURY RUBBERS Conveyor Belts are offered in following constructions.

(1) STRAIGHT PLY CONSTRUCTION

In this Construction; the carcass consists off UFL width fabric plies raid straight & the cover is of uniform thickness across the belt width as shown below in the sketch. BOTTOM COVER

(2) STEPPED PLY CONSTRUCTION :

In this construction, the top cover thickness is increased in the middle ofthebeft by reducing the carcass thick- ness. This extra rubber in the centre ofthebejt, where the wear is normally maximum, enhances the belt life without increasing the belt thickness. It also improves transverse flexibility of the belt a~the humberof plies inthecentreof .the belt are reduced. At least three straight plies are required to ihcorproate asteppedpJy construction while there can be either oneor two ply stepson the carrying side.
It Must be ensured that the impact rating of this type of belt should be based on the minimum number of plies in the centre of the belt while maximum puiley djameters should be considered on the basis of maximum number of plies at theedge of the belt.

(2) REVERSED STEPPED PLY CONSTRUCTION :

This type of belting finds its applications for handling submerged ash in boiler plants. This belt operates under water in a quenching trough. It is a reversed stepped ply construction with reinforced edges. As the beltis dragged agai nst the bottom surface of the quenchi ngtrough, wear on the pulley side of the belt isde. Hence the belt is offered with higher bottom cover than top cover thickness in HR grades. Such belting must be used with vuJcanlsed JoInt so that there should not be any carcass exposure which may be affected by water:

(4) BREAKER FABRIC :

In this construction a breaker ply is included in cover rubber.The breaker ply consists of an open weave (Leno) fabricmadeof cotton Of nylon topped on both sides with a soft rubber compound. This construction is recommended for applications where service conditions are severe and therefore , a bettter bond than usual betweeen the cover and carcass is necessary.)ncJusion ofa breaker ply inthe cover rubber increases this bond; The breakerpJy also improves cushioning and tear resistant properties of the cover rubber and protects the carcass from impact damages. A nylon breaker is preferred to a cotton breaker, where greater tear and impact resistance is required. Thickness of the braker ply is approximately 1.0mm. As the breaker is included rn the cover thfckness a minimum of 3.0 mm cqver thickness rs required to i ncorporatea breaker. A Conveyor Belt can have breaker in the following different ways.

(a) BREKAER ON TOP :

Here a breker ply is laid over the top fabric ply of the carcass

(b) BREKAER ON TOP AND BOTTOM :

Here a breaker ply is laid over both the top and bottom fabric plies of the Carcass and is recommended for those applications where bottom of the carcass as well needs additional protection.

(c) BREKAER ON TOP AND EDGES :

Here the breaker ply is turned round the edges & is recommended for those applications where both, carcass top and edges need additional protection.

(d) FLOATING BREKAER :

In this construction a ply of cushion rubber normally 1.5 mm thick is laid between the carcass face and the breaker ply. Applications where loading impact is very severe, call for this construction.

As cushion rubber ply and breaker ply are both included in the cover thickness, a cover of 5.0 mm minimum thickness is requ1red to incorporate a floating breaker .

(5) INTER LOCK EDGES:

MERCURY RUBBERS belts can be offered with interlock edge con. struction. This construction ensures better bonding between edge rubber and fabric and is recommended where wearing of edges is severe.

SKIM COATING :

For better bonding between plies & added flexibility, plies can be skim coated. Skim coating minimizes the possibility of ply. separation where severe flexing is encountered & improves impact resistance. Skim coating is offered as standard construction in Nylon/Nylon, Polyester/Nylon Carcasses. It is also offered as standard construction for Cotton Cotton Fabrics of 42 oz & 48 oz and for Cotton Nylon fabric of range above CN 80 in cover grades other than HR(Tl), SHR (T2), SHR180 oil resistant & flame resistant. HR (TI), SHR (T2), SHR180,OR & FR grade belts will have skim coated plies irrespective of type of fabric.

MILDEW INHIBITION :

The Carcass of Cotton/Cotton Conveyor Belts is sub- jected to attack by large number of moulds and vegeta- bles, fungus known as Mildew. Dampness and absence of Sun favor their rapid growth. Therefore, Cotton Fabrics being used in the Conveyor Belts are immunized by using mildew inhibitors in the rubber compounds.

ELEVATOR BELTING :

MERCURY RUBBERS Elevator Belting is designed for inclined conveyance of material by fixing metal slats or buckets on the carrying surface of the Belt at regular intervals. The belts are offered in 34 oz hard duck only.