UNICUT © - ServoDrive wire saw• Incredible 0-25m wire storage• Highest torque with UNICUT © -winding system• No interruption for wire storage expansion• Automatic wire twistingVisit us!Hall A1, Stand 329www.bauma.de/enDEMCO TECHNIC AGGewerbepark Oholten 23 • CH-5703 Seon, Switzerland56 PDi • Issue 1 • February - March 2013Phone: +41 62 769 6220 • info@demco.ch • www.demco.ch
detection, allows the saw to be operated on either a230V or 400V electrical network. The water-cooledhigh-frequency motor delivers 3.7kW with 230V,and 6.5kW with 400V. The maximum cutting depthis 165mm with a 400mm diameter blade.The TS 400 <strong>com</strong>bines an integratedwater supply through the spindlewith a ball-valve bypass systemto allow dry cuttingwithout overheating the engine. The blade guard isinfinitely adjustable. A screw fastener on the bladeprotection guard makes cutting blade replacementquick and easy.Makita’s EK7651H is world’s first four strokepower cutterThe K7651H, a 355mm power cutter is the latest additionto Makita’s extensive range of concrete powercutters. This new 30kW four-stroke engine eliminatesthe need for oil mixing, simplifying operation andpreventing engine failure due to improper mixes. Thesaw is also quieter, has a smoother idle for continuousoperation, and limits fuel consumption to less thanMakita’s EK7651Hworld’s first four strokepower cutterDr. Schulz’s DRS-TS 400handsaw1.69litres/h. A three-ring piston, improves engine durability,which is further enhanced by reduced exhaustand intake carbon build up.A no load speed of 9,350revs/min enables theK7651H to take on the most demanding applications.Other innovative features include automatic de<strong>com</strong>pressionvalve that reduces pull-starting force by 40%,and an integrated wheel kit that retracts when not inuse. In addition, the EK7651H has a five-stage foampaper-nylonfiltration system with direction airflowto provide cleaner air for improved engine durability.Darda tools delivery efficiency down underIn quite an unusual demolition project, the professionalsof the TAI Taucher, Atemschutz, Industriearbeiten(Diving, Respiratory Protection and IndustrialWorks) demonstrated the efficiency and advantagesof the 31kg Darda splitting cylinder C 12 N and the<strong>com</strong>bi-shears HCS 6 C. The setting was a 20m x 20munderwater building pit, where old concrete structureswere recovered from 8m underwater by means of thesehandheld demolition tools. The concrete foundationpiles, 2.5m long, and 1m diameter, as well as remainsof the reinforced foundation, had to be removed asgently as possible, as vibrations or concussions mighthave caused damages to adjacent buildings. Equallycritical were economics. Time is always money, after all,especially with special, unconventional demolitions.Several demolition techniques were consideredand quickly rejected. Pneumatic demolition hammers,as they suffer from a loss of power of0.1bar/m of water depth, hydraulic demolitionhammers, and as wire sawing were all deemedtoo time-consuming. Site conditions precludedthe other heavy demolition tools.As a result, a coordinated solution of handhelddemolition tools emerged as the idealsolution. A diver began the process by carrying outhorizontal core drilling at the predetermined breakingpoints of the concrete parts to be demolished. He theninserted the splitting cylinder’s wedge set, consistingof a wedge and two counter wedges, into the drilledhole. During the hydraulic operation the wedge pushesitself against the counter wedges, pressing them harderand harder against the inner wall of the drilled hole.Thanks to a splitting force of 3,507kN, the Dardasplitting cylinder C 12 N split both conventionalconcrete and reinforced concrete within seconds. Connectedto the hydraulic power unit at the surface vialong hydraulic hoses the splitter broke the concretestructures in the building pit exactly at the height of theboring, and widened the material until the reinforcingrodseither broke or were exposed.The remains of the foundationswith 6mm to 12mm diameter steel reinforcementswere then tackled by thesmall 14 kg hydraulic <strong>com</strong>bi-shearsHCS 6 C. With its shear set and acutting force of 214kN, this devicecan easily cut steel reinforcementsand round steel bar up to 18mmdiameter. When opening the shearset, a high breaking force is achievedto quickly split concrete. With thehelp of the HCS 6 C, the diver couldcut through unbroken steel and, whenpossible, further push the concrete apart togain better access to the reinforcements.Severing the reinforcements using Darda’s HCS 6C proved to be significantly faster and safer than usinghydraulic angle grinders due to the latter tools’ rotation,and limited underwater visibility around the workarea. Likewise, burning through of steel reinforcementis a <strong>com</strong>plex, ineffective, and relatively unsafe process.After each splitting and severing process, a cranelifted a total of 30m 3 of demolished parts from thedeep water. On land, the concrete could then be furthercrushed for transportation with the splitter andthe <strong>com</strong>bi-shears.Including all preparatory and follow-up work,the demolition was finished in 16h over two days.This was only possible in so short a time because thedemolition professionals of the TAI in Falkenhagen<strong>com</strong>petently applied the tools best suitable for the task.The <strong>com</strong>pany confirmed that the hydraulic Darda splitterdid more than simply save time. In terms of safetyand handling, especially in the case of underwaterdemolitions, there are no <strong>com</strong>petitive alternatives tocontrolled splitting.Darda’s 31kg Splitting Cylinder C12N andCombi-Shears HCS 6 C used for the underwaterdemolition water pit project to remove oldconcrete structures from 8m underwater.Issue 1 • February - March 2013 • PDi 57
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