Gift of the grab

Way back in 1927, engineering company Stothert & Pitt produced the very first specialised bulk handling crane to unload coal at Barking Power Station in London.

Times may have changed a bit since those halcyon days, but the key endgame for bulk handling cranes remains the same – to complete the task in a fast, efficient and productive manner. One of the most important crane elements is that of the grab – a simple device in theory but in practice, one that requires a lot of attention.

Ian Hassell of Hassells (which supplies Sennebogen cranes and material handlers throughout Britain) says that there are “three key elements when choosing the right crane grab: efficiency, performance, and health and safety. When you handle products, you need to have complete control so as to avoid any potential accidents – so that means choosing a crane grab that will reliably do the job.”

Indeed, Sennebogen found that its 870 M crane allowed for a high degree of productivity at Forth Ports. Four 870 M machines were used for the handling of bulk material, timber and other commodities – when doing so, the machines were augmented by double shell-type grabs, hooks, timber grabs and pulp grabs. And in only four months, the Sennebogen 870 M cranes resulted in high levels of productivity.

The UK's Shoreham Port also uses Sennebogen cranes, and its stevedore manager, Tony Oliver agrees that a good crane grab allows for higher productivity: “A good crane grab will make the process of cargo handling far more productive and a lot faster – this equates to using less fuel and so makes a difference on the environment.”

Shoreham Port has made two notable crane grab acquisitions in the last year. The first is a giant new hydraulic grab that allows for an extra-fast and efficient service on the port's new biomass exporting operation. The biomass is mostly made up of woodchip waste from the construction industries and large quantities of this are exported to areas such as Northern Europe and Scandinavia, where it will power environmentally-friendly power stations.

“The problem with some of the other smaller grabs is that they handle very little tonnage,” explains Mr Oliver. “But the great thing about this grab is that it handles a lot of tonnage and at a faster speed.” The Estonian-manufactured Orange Peel grab has a capacity of 10 cubic metres, which means that 2,000 tonnes of biomass can be loaded on to a ship in just 24 hours.

In addition, Shoreham Port has also bought a new Verstegen 6m bucket which will be used with a new Sennebogen crane, also purchased earlier in the year. “Because the new crane is heavier, we use both the crane and the new 6m grab for heavier bulk products such as salt,” says Mr Oliver. “This new grab again allows for more tonnage in one lift, which makes the process both faster and more efficient.”

Verstegen remains one of the key players in the crane grab industry, delivering more than 10,000 grabs to customers in over 80 countries, developing products that are tailored to customers' precise needs.

In the case of crane grabs, the old saying “One size fits all” definitely doesn't apply. The grab chosen needs to be the right one for both the type of crane and the type of bulk cargo. For example, a rope grab may not be the best choice when it comes to handling scrap and iron ore because it can't take the weight.

“One of the most important aspects of crane grabs is that you need to get it right the first time,” says Mr Hassell. “So the ports should always state their precise requirements.” Mr Oliver adds: “When it comes to choosing crane grabs, the first priority is that they need to match up with both the cranes and the task in hand.”

The grab selected needs to relate to the size and weight of the bulk cargo. Get it right and this will allow for a solid, efficient success. Get it wrong and not only will productivity be compromised, safety will too, if the crane operates above its safe working load.

Fortunately, Verstegen takes these potential problems into account – each grab is designed for the material that it will handle. In addition, all Verstegen grabs are provided with scales made of high tensile wear resistant steel, which means that all grabs are stronger and more resistant to wear and tear.

There are a number of different Verstegen grabs, which take into account the different requirements, sizes and tasks. Its clamshell grabs, for example, make the most of the wear-resistant, high tensile steel and bearing system combination to allow for extra strength. This means that they are suited to coal or ore handling. The Verstegen ore grabs are designed with extra closing force so as to deal with the heavy, abrasive qualities of ores and minerals. However, Verstegen's Orange Peel grabs are better suited to handling iron scrap, wood chips and rocks.

Having said that, different types of iron scrap need different Orange Peel grabs, and so the design of each grab must be adjusted. With that in mind, the manufacturer offers dedicated Orange Peel grabs for shredded scrap, heavy melting scrap and for pig iron and stones.

The manufacturer can also take other problems into account such as sticky materials (like nickel ore or bentonite) which can adhere to the wrong sort of grab. Verstegen's specially smooth scale designed grab (with special liners) solved the problem.

The world has turned since those days of 1927. While some may moan that more choices and over-reliance on technology are curses, in the port world, these are considerable assets. The crane grab may sound like the easiest thing in the world to buy, but in actual fact, it takes a great deal of thought and preparation to get right. And so thanks to technological developments, different varieties of grab and also environmental awareness, the perfect crane grab is there for the taking.

If you judge all the elements – size and weight capability or the type of cargo, for example, a good crane grab manufacturer will give you the product that you want for the efficient service that you want. And they'll also be used time and time again. As Mr Oliver concludes: “We have two 4m grabs that we bought six years ago – because they are both lightweight and strong, they have stood the test of time.”