Rope-winch systems used for groundwater sampling at opencast mines have to operate reliably and over long periods of time. Replacing the rope and rope guides is an expensive operation that can occur all too frequently. When a request was sent to the Völkmann Engineering Works the Dortmund-based repair company was able to revise the entire sampling procedure, which not only improved the efficiency and convenience of the system but also reduced component wear and the resulting maintenance costs to a minimum.
The rope-winch system in question was regularly used by a German energy supply company for groundwater sampling work. Before being redesigned by Völkmann the equipment was clearly in need of replacement, as the rope and guide system frequently required renewal, a process that resulted in high material and downtime costs. Moreover, the machine itself was very noisy. The engineers at Völkmann came up with an electronically controlled solution that was fine-tuned to the customer’s requirements and improved the previous mechanical system in every respect.
They fitted a new ballscrew and provided it with several new functions: the direction of rotation and position of the direction reversal is now calculated electronically using the movement of the rope drum and relayed to the ballscrew via a specially designed frequency converter and drive motor. A vibration damper/spring assembly ensures that the rope is kept uniformly taut and so can be reeled up in a precise manner.
The amount of rope paid out can then be accurately measured. The machine operator can program-in the required length to be reeled out, which can be as much as 1,000 m. Operating at a speed of at least 100 m/min the winch pays out the rope to the specified point, where the water sample can then be taken by manual control. The automatic system is then employed again to reel in the rope and empty the sample container.
Further information: Maschinenfabrik Völkmann GmbH
www.voelkmann.de
