Apex Enerka of Mackay has adopted Enerpac hydraulic cylinders to apply the pressure that is needed to vulcanise rubber patches onto the damaged belts that have become torn, holed or split from the wear and tear of conveying coal from the working faces of the mines.

The Oaky Creek longwall mine is a substantial customer of Apex Enerka and at any one time, Apex is likely to have several 400-metre rolls of conveyor belting from the mine on hand for refurbishing.

“We cut out the damaged pieces of belt and make patches that are vulcanised onto the belt under pressure at 150C for 50 minutes or so, depending on the thickness of the conveyor material,” said splicing foreman Stuart McMillan.

Heat is applied from beds of cookers above and below the belt being repaired. The beds are pressed against the belt by Enerpac hydraulic cylinders applying force at about 420 bar (6000 psi).

Depending on the size of the patching job, small square cookers compressed by a single cylinder are used or – for a repair to a lengthy section of split belt – a long cooker is used with three cylinders that slide independently but act in unison and can press three metres of belt at a time.

“Once the job is in place between the cookers, you turn on the valves controlling the cylinders you want and press the button on the electric pump until the desired pressure is shown on the gauge. A second button releases the pressure,” McMillan said.

Apex Enerka had previously employed a spot cooker in a frame that fitted over each of the holes in the conveyor to be repaired. Air pressure was used to secure the frame, but it couldn't achieve the degree of compression of the present equipment.

"We needed a quicker, more efficient method and also needed to patch larger areas. The idea of using hydraulic pressure seemed logical, so we looked into it and decided to go ahead.

"The system has been going for over a year now and is working very well. We've had nothing like it before. There was an initial expense, but it soon paid for itself.

"Following this success, another branch of Apex Enerka in Capella, Queensland, is looking at putting in a similar system there," McMillan said.

The RR series of double-acting hydraulic cylinders – with capacities ranging from 10-75 tonnes – are Enerpac's most versatile performers. Designed for lifting, pressing, production, construction and maintenance applications, they are rugged enough for the toughest job site uses, yet are precision designed for high-cycle industrial performance.

The RR1012 cylinder adopted by Apex Enerka has a capacity of 10 tonnes, a stroke of 305 mm, an extended height of 762mm and a collapsed height of 457mm.

Enerpac hydraulic cylinders and pumps are widely employed in engineering, production, shipbuilding, manufacturing, construction, industrial maintenance, metal fabrication, mining, transport and vehicle repair. They are among the most frequently used ranges of hydraulic cylinders and pumps in service in Australia and New Zealand.