With ports the world over going green in a variety of ways, a 34-year-old French idea has brought balance and savings to many with the added advantage of being good for the planet. Ray Dykes explains…
The concept of a balanced crane was patented in 1973 by the Seram Group of Perpignan, France, and has been often copied since. Seram remains the world’s largest maker of equilibrium cranes, as they are known, and has around 610 of the revolutionary machines working inland river ports and small ocean ports on every continent.An equilibrium crane has huge advantages when it comes to going green. Seram’s Sales Director Export, Dietmar Kajnath, says having an electric engine is a big plus over the fumes of diesel power.With a balanced crane, there are no toxic emissions, and a Seram equilibrium crane can save up to 75% of the power required by a conventional crane. Furthermore, there is low noise, low maintenance costs, high performance and a high lifetime cycle – Seram balance cranes regularly perform from 50,000 to 70,000 operating hours, something worth noting when the price tag for a Seram balance crane with 100-foot reach and 2,000 tonnes per hour capacity could cost as much as US$6 million depending on how it is configured. Across the border in Belgium, Indusign NV, an engineering company, built its first balanced crane in 1993 and today it is gaining widespread support around the world as the equilibrium or E-Crane. Such balance cranes are rapidly replacing the world’s aging fleet of conventional dock cranes as they are more productive and cheaper to run and maintain. E-Crane operators say they find them easy to use – there are two joy sticks instead of a host of levers and other controls and the cabs are quiet and air-conditioned – plus exceptional cab visibility allows accurate positioning of the grab with positive hydraulic control.
A balancing act
But, the balance crane’s secret is in the balance principle although they are not all built to the same pattern. Seram claims it has the only “real equilibrium crane” on the planet. But, balance is still what it is all about. E-Cranes, for example, are based on an ingenious parallelogram style boom that provides a direct mechanical connection between the counterweight and the load. Mark Osborne, President of E-Crane International USA, explains that loads imposed on the wharf (or cell) are balanced and do not result in uplift thanks to a pivoting counterweight. Pivoting on its axis, the counterweight moves using hydraulic cylinders so that as the load moves out the counterweight compensates and moves back, meaning the E-Crane is nearly always in equilibrium during its work cycle.
Most balanced cranes are mounted on a pedestal, but they can also be set up on rails, a crawler, high portal, or even on a barge giving them a huge range of bulk handling solutions. Most Seram balance cranes offer a similar range of mountings from freestanding to trolley, pedestal to gantry. Kajnath says a recent contract now loading at the French factory for truck haul through Belgium for shipment to a US customer, will be barge mounted.The sale also represents a new bulk product for Seram as it involves the transhipment of gypsum on the Mississippi River.The balanced barge crane will off-load from other barges and feed into a hopper and conveyor belt.
The year began slowly for Seram, which ranks itself as No 1 in the world. However, by April there were enough bookings to last until late summer 2008.“We’re normally booked out as we only build to customer specifications,” says Kajnath.The factory, which was given a 40% capacity boost earlier in 2007, can produce between 10 to 30 balance cranes a year, depending on customer configuration needs.The French company prides itself on ensuring every crane is “home grown” with no out-sourcing of parts or fabrication to “cheaper” plants in Eastern Europe or elsewhere. Each is French-built to meet rigid European harbour crane regulations and all models now feature an innovative new automatic load sensing system.
For E-Crane International, Osborne says the year is going well. E-Crane is “growing rapidly” in a niche market with its balance cranes priced in between converted hydraulic excavators (“cheaper but with lots of disadvantages such as poorer operator vision, diesel power, lower durability and productivity”) and purpose-built, dedicated continuous barge or ship unloaders with their high installed cost and high maintenance offset by higher productivity. “With E-Crane you are in the middle, having good productivity, low operating and low installed costs.” Currently, E-Crane International USA has 18 projects under contract, in manufacturing or in various stages of commissioning.“Since 2000, we have commissioned 37 E-Cranes in North and South America,” says Osborne.“We are becoming well known along the inland waterways as a provider of efficient, productive, reliable bulk material unloading equipment. Much of the conventional crane fleet is 30 to 40 years old and is at or near the end of its lifecycle; cable replacement is a never-ending ordeal; and operation of these cranes requires high skill levels,” says Osborne.“No wonder utility companies are now struggling to find a cost-effective, modern replacement for their aging, obsolete fuel handling equipment to keep abreast of the increasing demand for clean energy,” he adds. E-Cranes are seen as a way to “stay ahead of the game” and have become popular in handling coal and limestone (needed for flue gas desulphurisation) and other bulk commodities.
A case in point
American Electric Power, a large utility company with several plants in central USA, spent much time analysing which would be the right material handler to upgrade its aging bulk handling systems for coal-fired power plants.They chose E-Crane and so far,says Osborne, five have been installed and three-more are pending. And as an example of balance crane reliability and efficiency, Global de Venezuela uses two E-Cranes around the clock at Puerto Ordaz to offload bauxite between May 15 and December 15 – about 210 days straight. The E-Cranes discharge an average of 15 jumbo barges each day (over 3,000 in all) with a downtime record that is less than 0.6% of the total operating hours.
As for new innovations, E-Cranes can be checked out via satellite links anywhere in the world. Using an EMM (Electronic Machine Management) and Can Bus Electronics, the balanced cranes offer remote diagnosis via polling by GPRS allowing system upgrades instantly. Recently, an E-Crane indicated an under-temperature condition of the hydraulic circuit and refused to operate until the hydraulic heaters warmed the fluid to operating temperature. However, the E-Crane was already at operating temperature and this action would have resulted in overheating. The crane was remotely diagnosed and a faulty temperature sensor was detected and electronically bypassed.The E-Crane was able to offload a waiting vessel as scheduled and avoid a costly US$70,000 per day demurrage charge. Just another reason, it seems, to go for balance in your life and help save the planet along the way.
Source: World Port Development (Issue December 2007)