Bulk Grabs
Bulk Grabs can be applied to the handling of most dry bulk commodities. They come equipped with removable spill plates allowing for the work in cargoes of different densities. The grabs are suitable for many commodities from coal to pet coke, grains to aggregates and iron ore to HBI. Grabs are positioned in sets of three or four units at strategic ports or hub locations around the world including Gibraltar and Singapore or onboard controlled tonnage.
Setting up and expanding quayside facilities and terminals are long-term, cost-intensive undertakings influenced by a number of factors. Of crucial importance is the choice of the handling equipment because it is this aspect that influences the quayside infrastructure most decisively, as regards the rail tracks, foundations and power supply. Depending on the handling equipment chosen, savings of up to 15% in infrastructure overheads are possible. With existing terminals, it is also essential to include the track widths, maximum quay loadings and conveyor systems in the calculations for the supply of new handling equipment.
In the case of professional bulk handling, terminal operators can choose from a wide range of handling equipment options. In each specific case, however, the operator will want to consider and evaluate all the possible advantages and disadvantages of each option. The key factors are these:
- Type of bulk goods to be handled
- Proportion of total handling taken up by bulk
- Required handling performance
Advantages
- high handling rates
- handling of bulk goods,containers and general cargo
- extremely short delivery and assembly times
- diesel generator for operation independently of external power sources
- low specific investment expenditure for handling equipment and infrastructure on the quayside
- high degree of flexibility if the need arises for a quick change of cargo type
- simple procedure for travelling thecrane from one quay to the next
A bulk-handling crane is one that, instead of a simple hook that can handle a range of slung loads, has an integral grab for lifting bulk cargoes such as coal, mineral ore etc. Where the grab is a two-piece hinged bucket, it is known as ashell grab or shell bucket. Working the grab requires extra cables from the crane jib, so requires a specialised design of crane throughout, not merely an attachment. Some grabs use 2 cables for lift and control, others use 4. In 1927, Stothert & Pitt of Bath, Somerset produced the first specialised bulk-handling crane. This was to unload coal atBarking power station in London.
Orange Peel Grabs
Where a cargo is coarser in size than minerals, commonly for scrap metal, then an orange-peel grab may be used instead of a shell. These have six or eight segments of "peel" independently hinged around a central core. They are better able to grab at an uneven load, rather than just scooping at small pieces. If the load is made of long thin pieces, a grab may also be able to carry far more than a single "grabful" at one time.
Although orange-peel grabs may be hung from cables on a jib, they're also commonly mounted directly onto a jib. This is more suitable for grabbing at awkward loads that might otherwise tend to tip a hanging grab over. They may also use hydraulics to control the segments rather than weight and hoist cables.
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