Panorama Editorials Archive

Editorials Archive

Flexibility that pays - Mobile grain loading

FLEXIBILITY THAT PAYS - MOBILE GRAIN LOADING

Ely, March 2011 – Extreme weather events worldwide with droughts in Russia, Ukraine and other parts of Europe and adverse weather in the United States, Canada and Australia which has slashed output and put a lot of pressure on global grain markets. In the USA the situation is also very fluid, the price of corn, used to make livestock feed and ethanol, has soared 95 percent in the past year, wheat has surged 84 percent and soybeans are up 57 percent. On the London exchange, at the time of writing March futures are set at over £ 200 per ton, representing a more than doubling over the last three years.

With production pressures and ever increasing demand from emerging markets, particularly in the Far East, it is clear the price trend will be ever upwards, especially when the demand from bio-fuels are factored in.

Around the world virtually every crop has supply problems and grain inventories in particular are at their lowest level for many years. The market is volatile not only in terms of trading prices but also in terms of logistical demands with new exporters coming on stream in developing countries where established port infrastructure may not exists. Under such conditions the flexibility of mobile loading equipment is extremely attractive. It does not require a dedicated berth or any fixed handling devices and may load direct from truck to ship without double handling or risk of contamination.

British company B&W Mechanical Handling Ltd. of Ely started to develop the mobile Shiploader concept in the beginning of the1980s. Since then the company has delivered  approximately 100 Shiploaders of different types and sizes all around the world. In the grain trade machines are generally supplied to either the Port Operator, Shipper or Trader wishing to take advantage of present market conditions and where a fixed permanent grain elevator and export facility cannot be justified.  

A recent example is to be seen at the new Port of Great Yarmouth on the eastern seaboard of the UK. The cereals export facility is operated by Gleadell Agriculture Ltd. who have installed a new fully featured B&W Mobile Shiploader. This equipment will receive cereals from the local on-port storage facility or from farm stores located in the hinterland of the port all delivered by conventional road tipping trucks. When not required for ship loading the equipment may be motored off the berth, under its own power, and stored till required for the next shipment.

 
EFFECTIVE DUST CONTROL

 Minimising the environment impact, particularly from dust pollution, was a fundamental part of the design brief from Gleadell. Great Yarmouth is a well-known touristic destination and a typical Victorian style English seaside town with the beach close to the new port and as such any fugitive dust would be clearly a very sensitive issue.

The Mobile Shiploader included Twin SamsonTM Feeders which permit direct intake from tipping trucks. The material free fall from the truck to the feeder is very short so that dust generation is mitigated at source. With the dust control measures provided wind-blown dust pollution from the truck discharge is practically eliminated. Full dust control measures are extended by provision of a full enclosure to the ship loader boom with a dust filter at the conveyor feed boot and at the discharge to the trimming chute.

Control of the material from the boom head to the hold floor is absolutely critical from the dust control perspective in any ship loading operation. In Great Yarmouth the Cascade style dust controlled trimming chute was specified. Using a stack of inclined interlocking cones the material is constrained to flow in a Zigzag path to restrict the flow velocity. Only a small dust filter is required at the transition from the boom to the chute to fully contain any dust.

 

SPECIFIED FOR PERFORMANCE

 The performance of any truck to ship loading operation is effectively limited by the lost time in manoeuvring the trucks and moving the equipment to trim the vessel and the individual holds. Having twin SamsonTM feeders allows two trucks to discharge simultaneously therefore mitigating any lost time in positioning the vehicles. In this manner the equipment is able to achieve a spot rate capacity of 1,000 tons per hour handling wheat.

To maintain a high through-the-ship loading rate powered travel facilities with in-line and parallel movement is included to lessen the time required to reposition the equipment. In the Great Yarmouth arrangement the complete equipment may be moved as a single piece with the on-board diesel generator. No shore power is required. To bring the equipment to the berth the in-line travel mode is generally employed, but to move the vessel along the berth the wheels may be realigned for travel parallel to the vessel.

Of course parallel travel is ideal with vessels with a single open hold and no deck gear to obstruct the machine sideways movement. However, with a geared vessel the equipment must be moved to and fro to pass by the ships cranes. This more typical design puts even more pressure on the Shiploader powered travel system and the ability to change quickly from inline to parallel travel modes is critical. The B&W Mobile Shiploader is supplied with the latest version of the “New-Generation” powered travel gear including automated wheel alignment for all modes of travel. With this system each wheel set is mounted to a slewing ring with hydraulic jacking system and alignment actuator. This permits the wheel sets to be aligned for the desired travel direct using rotary positional transducers to signal the relative alignment and automate the change between travel modes. In addition the wheel unit alignment system provides for true Ackermann style steering in both travel modes controlled from the driver cabin on the Shiploader chassis.

 

THE UNIQUE STERLING SERIES BY B&W

Back in 2002 Gleadell Agricultural purchased the largest Mobile Shiploader ever built by B&W and, with a working weight of around 400 tons, probably the largest mobile Shiploader ever. Located at the port of Immingham and designed to operate on a dedicated berth but with the flexibility to park the machine clear and free the berth for other cargoes.

Known as the Sterling Series by B&W this is a very different design being based on the tower concept with vertical elevation and a radial outloading boom offering a high freeboard clearance within a compact footprint. To take full advantage of the deep water berth at Immingham this machine was designed to load Panamax size ships with a free board of around 15 metres.

For loading such vessels a high work rate is essential and for this purpose the Sterling Series machine was supplied with four integral SamsonTM feeders mounted in pairs to each side of the machine chassis. Using all four feeders the appliance can load at a theoretical rate of 1,200 tons per hour continuously but the operators claim a peak rate of 2,000 tons per hour was achieved.

In order to maximise the overall loading rate each pair of SamsonTM feeders are automatically speed controlled to maximise the receiving rate of each unit regardless of the load level on either and allow indiscriminate truck tipping without fear of overloading. This system is totally transparent to the operators who simply discharge the trucks as they arrive. The through-the-ship loading rate is related to the conveying capacity of the handling equipment and to the manoeuvring capability of the machine related to both hold trimming and moving along the vessel between holds clear of the ship’s deck gear.

In the Sterling Series hold trimming is effected by using the rotating trimming distributor and also the radial outloading boom by travelling the boom diagonally across the hold from corner to corner in both directions. When the hold is trimmed out the outloading boom may be moved parallel to the vessel and the complete equipment moved along the quay generally without the need to shunt back and forth, as is the case with a conventional design.

As with the machine at Great Yarmouth the Sterling Series includes Electronic Ackermann steering with precision rotational potentiometers to signal the wheel position. This system also allows steering without a physical linkage between the wheel steering units and at the same time maintaining an Ackermann style steering geometry automatically. Each wheel steering unit can support up to 120 tons live load on six tyres and a hydraulic jacking system is employed to stabilise the machine in operation and raise the chassis allowing the wheels to be aligned off load.

 

SMALL AND EFFICIENT: THE LANCASTER

For very much smaller vessels B&W are able to offer the Lancaster Series mobile conveyor for loading ships. Typically this size of machine will handle ships to 5,000 DWT depending upon the freeboard clearance over the quay level. Feeder Conveyors can be used to transfer grains from tipping trucks to the Lancaster Series allowing maximum flexibility of alignment on a congested berth. For this type of feeder conveyor the grains must be tipped through the small grain door and the feed rate manually regulated by opening and closing the grain door to avoid over feeding the conveyor.

These three projects by B&W represent grain export facilities ranging from small coasters through Handysize vessels up to Panamax ships covering the largest parcels of grain likely to be shipped. Loading the ship is clearly the last stage in the cereals export process from the farm gate. But generally between farm and port there will be a storage facility, particularly with cooperative organisations. For this purpose, alongside the mobile Shiploaders, B&W developed a mobile stacking solution for use in flat open stores, often converted warehouses: The B&W StormajorTM. It was the mainstay of the UK Intervention grain storage business from the early 1980’s and remains today the industry standard solution for loading to open flat storage in the UK, Europe and even in the Middle East.

B&W has its roots firmly planted in the grain handling business for the last 30 years offering high performance solutions to satisfy the ever expanding needs of the agricultural industry. This experience was never more relevant than today with an ever expanding world population and rapidly expanding demand from the major developing countries for meat products.