Keeping a hold
Grab innovation means bigger loads at faster speeds, finds John Bensalhia
For an article about grabs, it's appropriate that this one begins with a scoop: the latest offering from Nemag is now out there. Called nemaX, it's a brand new grab for iron ore. Combining low deadweight and high payloads with a short closing time, nemaX promises a 10% productivity increase for ports, lower maintenance costs and considerable time savings during the trimming phase.
Grabs are one of the most adaptable products used by ports. It's not enough to produce a one-size-fits-all style grab: size, type and practicality of the cargo are just some of the aspects for ports to consider when selecting the right crane grab.
Because of the constantly changing dry bulk terminal operator environment, new and innovative solutions are required to keep up with the times and the market challenges. With greater productivity, enhanced safety, lower maintenance costs and reduced labour costs as just four important elements for ports to consider, the right choice of product is vital.
Nemag already has a wide range of grab products. These include the invention of the scissor grab type, specialised rubber-lined lip sealing systems for handling powdered cargo, the patented Nemag quick-release link and the Nemag rope pear socket, and the award-winning introduction of a new generation of environmentally friendly clamshell grabs.
Building in these offerings, Nemag set out to develop an optimal grab by means of virtual rapid prototyping, a research and development project. The aim was to create a validated software design tool that could predict the combined behaviour of grab and bulk material. As a result, in conjunction with Delft University of Technology and the TATA Steel Plant in Ijmuiden, Nemag initiated a PhD research project and developed special simulation software that could analyse and visualise the interaction between grab and bulk material. The Virtual Prototyping Software System was the end result, providing valuable insight into the behaviour of grabs in material in a virtual environment and to help optimise the lifespan of worn-out elements of the grab.
Technology is also at the heart of Credeblug, which uses the latest software to add value and ease of use to the Blug range of grabs. A notable example is its GIITS (Grab Intelligent Interface and Transmission System).
GIITS establishes communication via radio-frequency between the crane and the grab, allowing port operators real-time control of different operating modules, forewarning of possible breakdowns affecting uptime and reduction in the number and cost of maintenance operations. It can be installed new or as a retrofit.
“The GIITS system is the result of a new approach to crane/handling unit communication,” says chief executive Asier Susaeta Diez de Baldeón. “Apart from our own electronics, we have developed specific sensors that centralise data reception and reduce the cost of data collection.
“The main benefit of GIITS technology is that it makes handling unit automation simpler and more economical. The technology even opens the door for the modernisation of equipment that does not have the necessary electrical wiring in the cable drum.”
Complementing GIITS technology is Blug Remote, an integrated data management and processing platform. “It enables data to be centralised and treated in order to facilitate the anticipation of potential production incidents and preventative equipment maintenance. Both the user and expert Credeblug personnel have online access to the different reports and stored/processed data.”
The information can be divided into two modules: Production (allowing for the control of the loading level of the ship) and Safety and Maintenance (with operation ranges and thresholds set for variables such as operating inclination, pressure and temperature). “The implementation of the two technologies in tandem improves the energy efficiency and the productivity of the crane/handling unit combination,” says the Credeblug executive.
Today's crane grabs must cater for all circumstances and meet sometimes precise requirements. Co-located at SSA Pacific's (Stevedoring Services of America) loading facility is Yara Fertilizer’s Stockton Gateway Terminal. Here, a wide range of agricultural products arrive at the dock, and a new crane bucket was required to manage the various loads.
A bespoke version of Mack Manufacturing's remote-controlled, diesel-powered bucket with spill plates was designed specially to manage Yara's heaviest materials, such as urea. The bucket needed was the right amount of mass to dig in to the loads, so the solution was the use of circular openings of the spill plates, as opposed to longitudinal openings along its width, preserving enough metal throughout the structure to maintain the integrity of the bucket in any configuration.
Because of the minimal change in the weight (with or without the spill plates), the bucket still has enough mass to dig into the load. The extra impact is ideal for moving urea, especially when the load has got wet and hardened in the hold.
This demonstrates how different materials have different needs when it comes to grab design. In the case of timber, hydraulic and electro-hydraulic timber grabs can handle wood in all sizes, whether it's a single block or a bundle. This is down to the grabs' high-load capacity, high closing force and specially shaped tongs.
Meanwhile, for finer bulk materials such as wood chips and pellets, crops and organic waste, port operators benefit from a different design. The Port of Antwerp, for example, uses Kinshofer’s C40HPX rehandling clamshell bucket. The Kinshofer C-series of grabs is particularly suitable for dealing with dry bulk biomass such as grains, sawdust and wood pellets. The model's HPXdrive opens and closes the two shells both synchronously and with constant force.
PEINER SMAG's motor grabs (such as its motor orange peel grabs) are also suitable for finer biomass materials. The special design of these orange peel grabs results in both fast operation and a higher degree of energy efficiency. This grab's individually driven shell segments also allow a greater level of adaptability when it comes to the handled bulk material and the design of the shell segment and the amount of shell segments on the grab can be adapted to meet the specific requirements of each port customer.
The orange peel grab is also a good choice for handling scrap cargo. It's a recommended choice for ports on account of the sheer amount of material that it can handle. A problem that some grabs can face with scrap material is that the shells can not close properly because of the large volume being transported. A product such as Verstegen's orange peel grab allows the port operator to manage that much more scrap because it boasts a wider opening and a larger grabbing capacity. The result? More scrap cargo can be moved, and with both greater efficiency and speed.
Whatever the cargo and whatever the requirement, the grab will always be there to give ports a helping hand.
CLIMBING THE CARGO MOUNTAIN
Grabs are hitting the big time in more ways than one.
No matter what the size of the cargo or target is, the modern grab can do the job. Manufacturers are not only upping the capabilities of the grab, but also the scale. For example, ORTS GmbH's recent radio controlled, diesel-hydraulic DHM 12m³ orange peel grab can handle large rocks, limestone, gypsum and scrap.
Meanwhile, at Able Seaton Port on the Tees, a heavy-duty dredging grab from Verstegen was chosen to be used in conjunction with the large-scale Liebherr LHM 600 mobile harbour crane. Weighing 28 tonnes and with a capacity of 16 cubic metres, the Verstegen grab is designed to increase the versatility of the Liebherr crane further at Able Seaton Port. Able UK executive chairman Peter Stephenson says: “Our growing list of heavy transport and lifting assets is an important element in maintaining our position as a market leader in providing multi-user port facilities.”
There is also the example of PEINER SMAG Lifting Technologies' EGF 60 high volume radio controlled single-rope grab, which has been put to use at Danish container port, the Port of Aarhus.
The port required a volume of 32 m³ which could be used with its existing crane lifting capacity. PEINER SMAG high volume single-rope grabs can handle material such as animal feed, and wood pellets and chips and include a number of special features such as a locking system (which can considerably reduce the height of the grab) and a sensor attachment that transmits actual operational states to the crane operator via wireless communication, ensuring faster and efficient results.
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