Time is money, but higher speed doesn't necessarily mean higher production — at least when it comes to industrial shredders for mixed materials. Because cars contain multiple materials — ferrous and non-ferrous metals, elastomers, and a variety of plastics — high-speed shredding could generate heat that would cause low-melting-temperature materials to gum up the works. On the other hand, having to rip through metals, tires, and other tough materials requires high torque — the ideal job for hydraulics. 

To transmit low-speed, high torque power for shredding, machines could use a gearbox to reduce speed and multiply torque from an electric motor. This often proves impractical, because the gearbox would be heavy and bulky, which would increase structural requirements. Also, shock loading often occurs when shredding blades suddenly encounter hardened steel.

Furthermore, materials often become wedged between shredding blades, making it necessary to quickly reverse direction of the blades to free the jam. Having to quickly and frequently reverse rotation would prove especially challenging for an electromechanical drive because of its high inertia.

Hydraulic technology rises to the occasion by offering drive components that are much less bulky and more well-suited to the demands of high-torque shredding. For example, a 60X85 Auto Shredder (not shown), from American Pulverizer Co., St. Louis, is driven directly by radial piston motors from Hagglunds Drives Inc., Columbus, Ohio.

The motors can generate high torque from pressures as high as 5000 psi. Severe jam ups that could damage gear drives simply cause these motors to stall. Stall conditions increase pressure in the hydraulic system, which triggers valves to automatically reverse rotation of the drive to free the jam up.

One particular challenge of the application was mounting. The radial-piston motor produces high torque in an envelope that consumes relatively little axial space. Using flange-or foot-mounted motors would have required an extensive framework. Instead, the motor is mounted directly to the end of a shaft protruding from the shredding chamber. The motor is kept from rotating by a torque arm. This arrangement provides a compact, simple, and easy-to-install drive system.

For more information on Hagglunds low-speed, high-torque shaft mounted motors, call (614) 527-7401, or visit www.hagglunds.com

              Advanced Fluid Controls has successfully revitalized as many as 30 of the VESTAS Wind-Fan Turbine Generators located in Palm Springs, California. We have carefully and cost effectively selected standard "off the shelf" industrial hydraulic piston pumps and solenoid operated spool valves to replace old obsolete products on 'Vestas Danish Wind Turbine Fan Generators' built originally with Parker & Parker-Bertea products. If you are interested in restoring an old design 'Turbine' versus purchasing the pricey "NEW TECHNOLOGY" conversion kits being promoted by others, give us a call.

Anthony Estrada @ Advanced Fluid Controls (714)540-8544

Nov 18, 2008 11:35 AM

Houston-based Waste Management has deployed four hydraulic hybrid-diesel garbage trucks in its Fort Worth, Texas, fleet.

The four trucks use a hydraulic system that captures and stores energy during braking. The energy is transferred to accelerate the truck to the next pickup location, which is expected to reduce fuel consumption and wear on the engine.