Hot Vulcanised Fabric Ply Belt Splice Procedure

Purpose. This procedure sets out how a site crew prepares, builds and cures a hot vulcanised step splice in a fabric ply conveyor belt on a customer site, safely and to the splice specification.

1.Before leaving the works

The crew leader must confirm the belt specification, the number of plies, the splice length from the splice table, the cover compound, the tie gum, the solvent and the cure time and temperature from the compound data sheet. Load the portable vulcanising press, the press plates and the splice kit, and check that the solvent, cements and uncured rubber are within shelf life and recorded in the Hazardous Chemicals Register. Complete the Job Safety Analysis Form for the job.

2.On site

Complete the customer's site induction and obtain the customer's isolation and permit for the conveyor. Verify the conveyor is isolated, locked and tested at the drive and that the belt is clamped on both sides of the splice area and cannot move. Apply your own personal lock. Set up lighting, fume extraction or ventilation for solvent use, and barricade the splice area. Never work on a belt that is not clamped and isolated.

• Customer isolation and permit in hand
• Drive locked and tested, personal lock applied
• Belt clamped both sides of splice
• Ventilation and barricades in place
• Job Safety Analysis reviewed with the crew

3.Preparing the belt ends

Mark out the splice on both belt ends using the bias angle and step lengths from the splice table, square to the belt centre line. Strip the top cover with the belt knife and stripping tool, then strip each ply step with the ply knife, taking care not to cut into the ply below. Buff the exposed plies and covers and keep the exposed fabric clean and dry.

4.Building the splice

Apply cement to the buffed surfaces and allow to dry to tack as the compound data sheet states, using solvent only with ventilation and gloves. Lay tie gum on each step, join the belt ends so that the steps mate without gaps or overlaps and roll out air. Fill the cover gaps with uncured cover rubber slightly proud of the belt surface and lay the edge strips. Check the splice for alignment and squareness before the press goes on.

5.Curing

Set up the portable press centred on the splice with the platens, pressure bag and edge irons in place. Apply the pressure and reach the cure temperature from the compound data sheet, then hold for the cure time. Record the start and finish times, temperature and pressure on the splice record. Allow the press to cool below 60 degrees before releasing pressure and removing the press. Do not rush the cool down.

6.Finishing and handover

Trim the flash, buff the edges and inspect the splice for lifted edges, porosity and alignment. Remove the belt clamps, remove your lock, hand the isolation back to the customer and observe the belt run at slow speed through the splice before leaving. Complete the splice record and the job card, and return unused chemicals to the works with the register updated.