A pre series Pentruder 3P8 wire saw from Tractive was recently put through its paces during a performance test, cutting down a railway foundation on a jobsite in the city of Eskilstuna in Sweden. As the train traffic was limited to half the capacity during the down time, the time schedule was very tight. The cutting was planned to continue uninterrupted, 24 hours a day, with staff working in three shifts.
To be sure the job could be finished within the specified time frame, the contractor, “Betongborrar’n”, had planned to use three different wire saws. After attempting to setup the other wire saws, it was decided to go with the Pentruder 3P8 for all of the cutting. The length of wire in contact with the concrete prohibited the use of their smaller machine, as the wire would slip on the pulley much of the time. Problems with getting the bigger “industry standard” machine close enough to the object to be cut, and securing it to the scaffolding it had to stand on, prohibited the use of that machine.
“The fact that the Pentruder 3P8 wire saw could be fitted directly on the concrete foundation, to make a “direct cut”, saved us a lot of time and trouble when setting up the machine. In contrast to our bigger machine the lightweight modules can be mounted directly to the surface being cut. Together these features made the setup quick and convenient”, says Anders Jäderholm, partner of Betongborrar’n. “
The foundation that was cut down was approximately 2 meters (3’) wide and 8 meters (26’) long. The pieces were then cut in several 2 meter long by 1.5 meter (5’) wide by 2.5 meter high blocks. This was the biggest size which could conveniently be transported away from the jobsite.
The bottom cut was 2 x 8 meters, (6.5’ x 26’), for a total area of 16 m2 (172 sq.ft). This cut took 3.5 hours including some problems with loose material which jammed the wire. For the whole job, the performance was never below 4.5 m2/hour (48 sq.ft./hour). Typically 5 m2/hour (54 sq.ft./hour) and upwards was achieved when conditions were best.
The cutting went very well and the contractor especially appreciated the big wire magazine and the smooth operating automatic feed control. “This is what it should be like”, comments Anders Jäderholm. “It’s so easy to operate, and we have never seen a wire saw that can start the wire like this. We didn’t even chamfer the corners. With the other saw, it would require several additional satellite pulleys, and a lot more time to complete the setup. Another big plus with the Pentruder 3P8 is the fact that the feed control is entirely electric and there is no need for an air compressor. For us this is especially important in the wintertime in damp and cold conditions.”
The job was successfully finished well within the specified time frame and the contractor “Betongborrar’n decided to invest in the new Pentruder 3P8 even before the job was finished.
In the 3P8, the manufacturer has taken steps to reduce wire wear by careful design of the pulley configuration, which aids in the wire rotating to prevent the wire form wearing flat on one side only. A special rubber compound has been developed to improve traction to prevent wire slippage and prolong the life of the main drive pulley. The design of the pulleys allow the rubber inserts to be replaced quickly and easily.
The Pentruder 3P8 wire saw is part of a system that can be expanded to include a wide range of High Frequency equipment. The current range of five different HF-driven wall saws and the MD1 core drilling machine will be followed by products now in development, such as a corner saw, chain saw and floor saw.