The unique design of the hermetic seal system not only protects the bearings but offers maximum effectiveness and long life, even in the presence of the most sever pollutants.

The control of all roller materials from incoming inspection, through manufacture and assembly in the automatic cycle, with on line function tests on 100% of production, allows our supplier to state that the function and life of this roller is among the highest in the world.

Attention to detail, whether at the design state or in the various manufacturing phases, observing close limits of staring resistance, of eccentricity and axial play, results in notable savings in energy and a reduction in maintenance over time.

These factors give rise to business economies, confidence and high productivity, objectives pursued by all users of belt conveyors.

The "Quality System" certificates awarded to our supplier attest to their continuous quality standards, and their stated performance.

Roller shell
It is the external diameter of the roller that is in contact with the conveyor belt. It consists of a steel tube produced according to our supplier's standards, with particular reference to tight tolerances and specific particulars.

The tube is cut and machined using automatic numerically controlled machines, that guarantee and maintain the tolerances and the precision of the square cut.

Bearing housing
It is a steel monolithic structure, deep drawn and sized to a fine tolerance ISO M7 at the bearing position. This tolerance is necessary to guarantee the optimum assembly of the bearing by ensuring that it is square to the spindle of the roller.

The thickness of the housings is proportional to the spindle diameter and to the bearing type, with thicknesses that are up to 5 mm, to guarantee the maximum strength of each application, including the heaviest.

Monobloc
The bearing housings of the HDS rollers are welded to the tube body using auto-centralising automatic welding machines utilising a continuous wire feed: our suppliers patented system.
Tube and bearing housing form a monolithic structure of exceptional strength which itself reduces to the minimum imbalance in the roller. This guarantees the alignment and concentricity with respect to the external diameter of the component parts of the sealing system.

The optimum balance and concentricity thus obtained allows these rollers to be used at the highest speeds, eliminating harmful vibration to the conveyor structure and the "hammer effect" on the bearings of the rollers.

Spindle
This is the component which sustains the roller when it is assembled in the troughing set supports. It is made from drawn steel, cut and machined by automatic numerically controlled machines.

The spindle is centerless ground to a tolerance ISO h6 at the extremities, corresponding to where the bearings and seals are fitted, to guarantee a perfect match and optimum performance.

Bearings
These are the parts which give virtually frictionless rotation to the tube body with respect to the fixed spindle.
Only precision bearings are used. They are the radial ball race type of the series: 6204, 6205, 6305, 6206, 6306, 6308 with internal play tolerance C3, ideal for applications of rollers used for belt conveyors.

Connecting spindle / bearing, bearing housing
HDS rollers require particular tolerances for the bearing housing, for the spindly and the bearing itself, that enables the roller to function optimally for a long life, whilst under pressure.
In fact the bearing housing has the very strict precision tolerance of M7, the spindle is precision ground to tolerance h6 and the bearing has an internal play tolerance maximum C3.

These three tolerances functionally guarantees the auto-alignment of the internal and outer bearing rings of the ball race resulting in a good performance oven when the spindle deflection is extreme doe to overloading.

Sealing
The seals comprise the most important components in the design of the HDS rollers.

The principal task of the seals is to protect the bearing from harmful elements that may impinge from the outside or the inside of the roller.

The working conditions of these rollers are very often the most severe, with the presence of dust, abrasive sand, water and various other pollutants.

On the side of the roller there may be particles formed by the rusting of the internal tube body or condensation caused by the thermal changes that arise between day and night in particular climates.

The seal must also contain and retain a good quantity of grease for the bearing lubrication.

As a guarantee and to complete the HDS roller sealing system the final components are assembled at either end:

• strong external stone guard formed as a shield, in anti-corrosive material, to protect the seals from the fall of material onto the end cap of the roller.

• seal with two principal sections; an external and one internal.

• external section: self cleaning in that it centrifugally repels water and dust naturally toward the outside. Comprises a lip ring seal made from soft anti-abrasive rubber with a large contact surface that provides an effective hermetic seal of long working life.
  The self cleaning effect is principally due to the particular design of the cover cap and the shape of the bearing housing which when rotating, tends to expel all pollutants, centrifugally.

• internal section: triple labyrinth in nylon PA6 greased to give further bearing protection.
  Behind the bearing a sealing ring in nylon PA6 is positioned that provides an ample grease reservoir and also retains the grease near to the bearing even when there is a depression due to an abrupt change in temperature (pumping effect).
  This ring acts also as a seal to counteract the eventual formation of condensation and oxidation which could take place inside the tube.

• locking system, provided by means of the correctly located circlips, which today is the best and strongest system implemented in heavy rollers for belt conveyors.

Lubrication
HDS rollers are lubricated for life with an abundant quantity of lithium based water repellent grease, that guarantees the correct lubrication for the working life of the rollers.

Final inspection
All HDS rollers are assembled on automatic assembly machines with live test stations that maintains roller rotation for a sufficient time to distribute the grease into the bearings and all the other internal components. 100% of the rollers are tested to verify their low-torque characteristics.

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