Plastic Impregnated Wire Ropes
The benefits gained when using PIR are the result of their exclusive patented fabrication.
Standard lubricated Shaw's Wire Ropes used in the fabricating process have their individual
strands and wires impregnated with a sealing thermoplastic material which forms a protective
layer between the individual strands and around the core of the rope.
The end result is a balanced, sealed-lubricated wire rope that provides exceptional performance
and extended service life when working under severe operating conditions.
Improved wear resistance
PIR's plastic impregnation acts as a shield to prevent infiltration of solid abrasives and,
combined with the locked-in lubricant, eliminates weaknesses due to internal deterioration.
Improved fatigue resistance
The plastic impregnation of PIR wire ropes reduces wire contact bending stresses thereby
improving load transfer and sharing between wires and strands - unequalled by conventional
wire rope.
This ensures continued flexibility and substantially lengthens the rope life. PIR wire rope
will accept all standard end fittings.
PIR for safety
High visibility bright orange plastic is used in the fabrication of PIR wire ropes.
Reduced drum and sheave wear
The plastic impregnation and infill produces a rope with a completely full cross-sction. A
full pitch circle is presented to those parts of a machine which both cause wear to the rope,
and are worn by the rope. The radial pressures exerted by conventional circle cross-section
eliminates rope groove marks in drum laggings and sheaves allowing the PIR rope to adapt
closer tolerances-minimising bend stress over sheaves and further increasing fatigue life.
Less maintenance
Such increased wire rope life means there have been considerable cost-saving spin-offs,
including reduced machine down time because of fewer wire rope changes, quicker wire rope
changes due to the ease of handling PIR's lubricant free surface, and less maintenance of
drums and sheaves required due to the polishing effect of PIR's fully circular cross section.
| Nominal Diameter |
Approximate
Mass |
Minimum Breaking Load |
| mm |
ins |
kg/m |
tonnes |
kN |
| 16 |
5/8 |
1.13 |
16.4 |
161 |
| 19 |
3/4 |
1.59 |
23.1 |
227 |
| 22 |
7/8 |
2.14 |
31.1 |
305 |
| 26 |
1 |
3.00 |
43.4 |
426 |
| 28 |
1.1/8 |
3.46 |
50.4 |
494 |
| 32 |
1.1/4 |
4.53 |
65.7 |
645 |
| 35 |
1.3/8 |
5.42 |
78.7 |
773 |
| 38 |
1.1/2 |
6.40 |
92.8 |
910 |
| 40 |
1.5/8 |
7.10 |
103.0 |
1008 |
| 44 |
1.3/4 |
8.60 |
124.0 |
1220 |
| 52 |
2 |
12.00 |
174.0 |
1704 |
| 56 |
2.1/4 |
13.60 |
201.0 |
1976 |
| 60 |
2.3/8 |
15.60 |
231.0 |
2268 |
| 64 |
2.1/2 |
18.50 |
262.0 |
2570 |
| 67 |
2.5/8 |
20.30 |
288.0 |
2825 |
| 70 |
2.3/4 |
22.20 |
314.0 |
3080 |
| 76 |
3 |
26.40 |
370.0 |
3630 |
| 83 |
3.1/4 |
31.00 |
442.0 |
4336 |
| 89 |
3.1/2 |
36.10 |
508.0 |
4983 |
TYPICAL APPLICATIONS
Blast furnace - skip hoist
Severe problems caused to conventional ropes through airborne attack by rain, marine salt,
etc. causing internal corrosion, aggravated by a constant lengthening of the rope lay in
service, requiring frequent adjustment to compensate.
PIR gave a 50% increase in working life and no adjustment to rope lay extension was required.
An important additional benefit was the lack of need for secondary lubrication of the rope,
in service, thereby keeping the rope itself and the machinery in a clean condition.
Riser tensioner ropes
Tests on PIR riser-tensioner ropes, removed after 15 million ton cycles (almost three times
the expected life of conventional rope), revealed no signs of external damage, minimal internal
wire corrosion, and retention within the rope of good amounts of lubricant.
Dimensional checks showed that there had been no reduction in nominal diameter nor had there
been any extension in rope lay. A destruction test on a used sample length produced a breaking
load of 145.7 tonnes (compared with the required minimum of 124 tonnes).
Face shovel ropes
Following a series of monitored trials, on a 195 RB face-shovel, PIR ropes out-performed
conventional wire ropes by a factor of 2.5:1. On crowd and backhaul duties, the results were
even more impressive - with PIR producing a working life equivalent to three times that achieved
by normal steel wire ropes.
Ore-unloader cranes
PIR ropes are well proven on this arduous application involving the unloading of material,
by dockside cranes, in conditions where dust and debris are prevalent and where rope chafing
is unavoidable. Use of PIR ropes on such cranes in Teesside, South Wales and Europort, has
produced outstanding extensions in working life.
Logging
PIR type, plastic-impregnated ropes, are the norm, in North America and New Zealand, on
sky-lines and haulbacks, saw-mill carriage ropes. The extreme wear-resistant properties of
these ropes are further enhanced by the high visibility of the orange plastic impregnation
- especially important on sky-line applications.
There are applications where the centre (core) of the wire rope is subject to more abuse than
the outer strands themselves. For these applications, it is possible to impregnate only the
steel core itself, and to lay around it either conventional, or compacted, strands; thus,
the outward appearance is that of a normal rope. The benefits of the plastic-impreganted
core are:
- Increased resistance of the core to crushing, thereby providing better support for the outer strand.
- Improved resistance to bending fatigue
- Retention of lubrication reduces internal corrosion and decreases internal wear
- Increased surface area reduces contact pressure and wear between the core and the outer strands
