Production • Processing • Handling
damaged, which consequently has to be discarded. A possible remedy is an inserted metal sheet that suitably regulates the utilisable drum width. Te rope length must be selected such that the
first layer is partly unwound. Tis helps prevent issues when changing between the first and the second layer and between the second and the third layer. At the same time, it can be avoided that the first layer is used as auxiliary grooving. After the rope has been installed, it is essential
to break the rope in under various different load cycles. Tis also includes running through the load quadrangle several times. Tis helps prolong the service life of the entire Drum – Rope – Sheave system.
Maintenance/inspections Regular relubrication helps prolong the rope’s useful life span considerably. However, not all types of grease are suited for relubrication, as it needs to be compatible with the grease originally used by the manufacturer Teufelberger conducts grease tests on a regular
basis in order to continually update the list of compatible lubricants by including new grease products. Incompatible grease may cause the remaining original grease to be removed from the rope. As a consequence, the rope will reach its discard condition faster, as its lubrication will be insufficient. In addition to ongoing maintenance,
inspections are another useful measure in order to detect possible signs of wear and, where necessary, initiate countermeasures on time.
Discard criteria Teufelberger recommends compliance with ISO 4309 which defines discard criteria such as the number of broken wires, the inspection of the actual rope diameter, external and internal corrosion, deformations, etc. In order to determine the acceptable number
of broken wires in the context of either single- layer or multi-layer winding, regular lay or langs lay ropes, we rely on the so-called Rope Category Number (RCN). Te RCN as such does not provide any information on the life span of a rope, but it indicates only how many broken wires over a length of 30 times the rope’s nominal diameter or six times the rope’s nominal diameter, respectively, are acceptable.
Prolonging a rope’s life In addition to the ongoing maintenance of the rope, the so-called slip and cut method is used to substantially prolong a rope’s life span. In (and only in) multi-layer winding, the greatest stress acting
It is recommended that you employ the slip and cut method – and this is especially true if you proceed in accordance with the total cost of ownership principle. Under this principle, it is not the mere costs of
replacement for the rope that are compared but all costs incurred in connection with exchanging a rope (costs of the standstill, maintenance costs- and costs of the rope change, etc).
When looking at things in this way, many cases demonstrate that the long-living special ropes may be more expensive in terms of their purchase price, however, in total end up being markedly cheaper than conventional steel wire ropes because of their longer service life.
Troubleshooting When encountering winding problems during day-to-day operation, it is possible for the user to undertake a number of measures in order to determine the cause.
www.engineerlive.com 33
Fig. 2. Measurement of drum pitch with the help of groove gauges.
on the rope occurs at the cross-over point between layers. Hence, this constitutes also the region limiting the life span, as the first broken wires will invariably appear in the region exposed to the greatest loads In the slip and cut method, the rope is
shortened by about one third of the drum’s circumference at the rope’s point of attachment on the drum. Tis way, the cross-over point is shifted and consequently the life span lengthened. In this procedure, it is necessary to devote special attention to the rope severing procedure and to the discard criteria stated in ISO 4309.
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52