The Hilti Corporation, headquartered in the Principality of Liechtenstein, has developed a revolutionary control system – Hilti Traction Control (HTC) – which enables drilling and sawing contractors to achieve up to a 30 per cent higher concrete cutting performance, while ensuring that optimum use is made of the available power for sawing systems.
“In order to remain competitive, concrete drilling and sawing service contractors must constantly increase productivity – which means they have to ensure sawing more concrete in less time. Although, it is understandable that the industry would demand for sawing systems with increasingly powerful motors, this is not always the best solution as the electric power available on construction sites is presently limited to 63 amps,” says Milos Hrabek, market segment manager at the Hilti Regional Office.
“Bearing these factors in mind, Hilti’s engineers set out to achieve a further significant increase in cutting performance – and the solution that the experts from Liechtenstein came up with, breaks all records among medium to heavy-duty hydraulic wall saws,” states Hrabek.
HTC achieves peak wall saw performance by ensuring maximum power is being transmitted to the concrete. This electronic advance control system, which is incorporated in the hydraulic unit, not only prevents stalling of the blade but also ensures that the available power is used to maximum efficiency, he points out. Performance losses as a result of the control point being set too low, or due to continual power adjustment in both directions, are thus reduced to a minimum.
HTC makes life easier for the operator as it reacts automatically to various base materials; to contact with rebars; and to different saw blade specifications. The electronics achieve this by measuring the mains power available, the current input, the mains voltage, the hydraulic pressure and the oil flow rate, he explains.
“Taking all of this data into account, including how well the saw has been cutting previously, the system calculates the maximum rate of advance and determines whether speed should be increased or decreased, for example, when cutting through steel,” Hrabek adds. “To achieve the best possible cutting performance, the HTC system compares the calculated values, up to 100 times per second, with the mains power limiting value set by the operator on the digital remote control unit.”
Tracing the development of power control and advance control systems, he says: “Wall saws of the first generation had no advance control system. An experienced operator was required to carefully monitor speed of advance, the noise produced by the saw and the operating pressure indicated by a gauge. He then adjusted the speed of advance accordingly”.
Systems of the second generation were equipped with hydraulic valves that regulated the advance pressure within a certain range depending on operating pressure. This development brought about a significant improvement in operating comfort. With a view to improving the speed and accuracy of control, third-generation wall saw systems were fitted with electrically-controlled proportional valves in place of the inflexible mechanical valves. An analogue electronic system provided the controlling values by measuring current input.
In the HTC system, a number of sensors supply the currently effective saw drive parameters to a super-quick digital system that then uses this information, in conjunction with previous data, as a basis for calculation of the optimum control values.
“Even after only one cut, the operator notices the positive effect of the new control system on the saw's performance and thereby on his productivity in terms of cut surface area in square metres. The new HTC system completely eliminates the pulsating advance movement experienced with previous advance control systems,” Hrabek adds.
Among the range of wall saw systems that Hilti offers is the Hilti D-LP 32/DS-TS 32, a powerful, safe and convenient modular unit designed for heavy-duty wall sawing applications in steel-reinforced concrete. It also provides the basis for hydraulic core drilling, plunge sawing and wire sawing.
The HTC system’s exceptionally high performance has also called for new saw blade manufacturing technologies. Hilti’s new-generation wall saw blades are distinguished by their special three-tooth sandwich segments. These blades are optimally matched to the characteristics of the wall saw’s innovative performance control system and thus, in conjunction with HTC, achieve previously unattained cutting performance.
“In a nutshell, the new Hilti hydraulic wall saw system can apply its immense power optimally, making it possible for trade professionals to achieve up to 30 per cent higher cutting performance and in turn cut sawing costs, by cutting faster,” he concludes.