01 July 2015
Powered by oil hydraulic pressure, Delta Hydraulics' double acting telescopic cylinders have become a vital component of most equipment used in Australia's waste industry. The force generated by the hydraulics moves the cylinders in two directions - both extending and retracting. It's why waste equipment provider, Bucher Municipal, exclusively fits them into its Force front loader and UrBin rear loader models. Like a car being crushed at the wreckers, these cylinders will perform the same task, albeit with waste inside a moving vehicle.
"The double acting telescopic cylinders have the ability to extend out and retract under powered hydraulic pressure, making it ideal for compacting waste once it's picked up by the refuse unit and then emptied into the vehicle's body," says Darrin Pritchard, Director of Operations at Bucher.
For more than 20 years, Bucher Municipal has been a client of Delta Hydraulics. On average, Bucher will fit double acting telescopic cylinders in up to 10 units a month in both its front or rear loading waste vehicles.
John White, Director of Delta Hydraulics, explains the intricacies on how the double acting telescopic cylinders operate. "In front of piston ported double acting telescopic cylinders, the pistons control the phasing of the cylinder. Once extended, the stage goes into regenerative mode, holding in the extended position and allowing the smaller piston of the next stage to exert force on the load it is crushing," he says. "The multi-stages of the cylinders allow for a long length of travel, but with a short, closed retracted length making it suitable for large volume collection vehicles."
The double acting cylinders also function speeds up to 200mm/sec when in operation. Each stage is microcrack hard chromed. "The 0.2Ra finished chrome on all stages means that there's less friction on the seals enabling these operating velocities." John says. "Chrome also helps to prevent corrosion in the cylinders, which in the waste industry is a massive problem considering all the unknown chemicals that can accrue from dumped waste."
The internal makeup the cylinders consists of hollow stages that dimensionally fit inside one another, and are inside diameter and outside diameter (ID/OD) finished to a strict tolerance. The last stage of each cylinder is equipped with one oil connection to the tension side and one oil connection to the pressure side. The hard seals on the pistons of each stage are needed to limit abrasion between the oil transfer holes and ports over which they must pass. "All piston ported double acting telescopic cylinders have pistons fitted with seal rings where as single acting cylinders have only a piston fitted with a wearstrip that acts as a guide or stabiliser," John describes.
According to John, to allow the cylinders to move freely through each segment, oil-transfer holes are built into each stage. These holes are located just above the pistons in the body of the stage. The retraction port normally is located in the top of the smallest stage. Oil flows through this port and into the smallest stage.
"The piston rod in the middle of the cylinders also extends out and feeds oil to all the stages," John says. "The oil transfer hole allows oil to enter and pressurize the volume between the next stages internal diameter and the smaller stages outer diameter. Pressure in this annular area generates the force to move or retract the smaller stage into the larger stage. It's a complex process, but the way the cylinders are constructed allows for a seamless performance."
Having dealt with Delta for almost 20 years without any major issues, Bucher didn't see a need to change the dynamic, even after MacDonald Johnston was acquired in 2004. "John White and his team continue to supply quality cylinders that are yet to let us down," says Joe Kuszer, Procurement Manager for Bucher Municipal. "If needed, we can simply ask John to customise the cylinders to suit our vehicles, which can include refuse units with just one double acting telescopic cylinder fitted, or sometimes two cylinders. On top of that, Delta's turnaround time is fast and we don't have to wait to long to get them into our factory."
With more than half a century in providing waste management solutions worldwide, Bucher Municipal can boast a diverse fleet that includes side, rear and front loaders, as well as static compactors. The company says that without the help of Delta Hydraulics' double acting cylinders and its backup support, Bucher vehicles wouldn't be able to perform at a consistently high level.