Mechanical ship unloaders taking centre stage

KEEPING COMPETITIVE

Mechanical unloaders in particular — such as the Portalink range — are setting market standards in terms of low energy consumption, high operating efficiency due to easy handling for operators, high availability due to reduced maintenance time and low wear- and-tear. This all means that buyers can expect a short return on investment (ROI), making them an excellent choice economically.

In the last year, Bu¨hler has focused on a new operating and control system for its loading and unloading portfolio. This new operating system has
been developed as a response to direct customer feedback, and simplifies multiple functions. It also increases functionality for maintenance and
traceability. This results in a reduction in the time needed to search for errors or train new staff to understand the equipment, greatly improving ROI.

RECENT CONTRACTS

Contracts that have recently been received by Bu¨hler include:

TECHNOLOGICAL EXPERT

With more than 100 years of experience building mechanical unloaders, Bu¨hler has a large and global base of installations. With their high and reliable quality, many of the older mechanical unloaders are still in use even after 50 years, and form the backbone of many companies. To even further extend the operating life of its equipment, Bu¨hler has developed several service packages. One of the new service packages is a complete or part retrofit of the marine leg, the heart of the mechanical unloaders. With a less-than-optimal functioning marine leg, not only is performance reduced, but also unexpected breakdowns result in unscheduled and expensive repairs. With the retrofit offered, Bu¨hler diagnoses and intervenes ideally before or when interruptions happen, thus reducing risk and or costs.

The environment is constantly changing and there is a need to become increasingly aware of the problems that surround it. This is why Bedeschi always pay attention to environmental issues, basing its projects on the stability and sustainability of the surroundings.
Nowadays there is often a need to transport raw materials and combustible solid material from one continent to another by sea. The ships that
do this are becoming bigger, so the modern port has to be equipped with all kinds of machines like shiploaders, ship-unloaders, cranes, conveyors, etc. to be able to complete the vessel’s loading/unloading process in the minimum time.

To guarantee efficiency in the ports it is necessary to optimize the position and the volume of the material that is stored and in transit, waiting to be shipped, to have adequate machinery to reduce the time of loading and unloading of the ships, and the delivery of the raw material. It is also necessary to organize the layout of the terminal in the most functional way and to reduce the number of operators needed through automation of the process, creating eco-friendly terminals by using dedusting equipment.

Thanks to its wide experience and knowledge in material handling, Bedeschi is successful in all of the above mentioned aspects. For example, when considering the bucket chain continuous ship unloader (CSU), all the solutions that Bedeschi proposes, and the executive design, are developed with the utmost care to dust control. The CSU will travel on rails and will be travelling and luffing boom type, it will be equipped with a bucketwheel elevator with continuous rotation for digging, with belt on the boom and central hopper to unload on a feeder that will load the pier conveyor.

When unloading, the material reclaimed by buckets will be luffed to the unload point, on the top of the elevator, and unloaded on a rotating plate which, independently from the rotation position of the elevator, will convey the flow on the boom belt. From the boom belt, through the central hopper, the material will be unloaded on the belt feeder under the hopper that will convey onto pier conveyor.

The proposed design with fixed foot will allows to extend the elevator enclosure, leaving the foot only on open air. While in operation, even at the real beginning of the unloading, the elevator foot is almost entirely inside the hold avoiding any possible dispersion. Once the material is inside the buckets, the entire stroke is protected.

Drive sprockets of the elevators will be equipped with a suitable device to avoid any possible egress of material inside the elevator enclosure.

CSUs are normally compared with a traditional grab type ship unloader. While the grab type ship unloader, even if equipped with ecological grabs, does not make it possible to completely eliminate dust dispersion during the transfer from the hold to the hopper — especially in windy conditions — with the CSU the route of the material is completely enclosed and the transfer points are equipped with dedusting systems.

This means that, once reclaimed by the buckets, the material can be fully enclosed without any possible dust dispersion.

Particular care will be taken to avoid any material accumulation inside the elevator in order to avoid any possible material falling during machine transfer operations. The unloading chute will be closed, with sealed inspection doors.

This is why the CSU ensures a homogenous material flow, with dust kept to an absolute minimum.

Going green and sustainable practice is now seen as an essential part of any business in the bulk industry.

Considering the fact that port’s infrastructures which consists of the land and space necessary for operations is expensive, Bedeschi is able to help the client by providing compact, functional, and eco-friendly machines that are able to adapt to a smaller space but are still able to offer the high volumes requested by the client.

Ship unloaders are a well-developed technology that work continuously and reliably. While there are different types suited to different materials, a common factor is the need for effective control and monitoring to be maintained at all times to both ensure trouble-free operation and to calculate the weight of cargo being unloaded.

Real-time monitoring data from unloading systems is key for safety, operational and commercial reasons. When it comes to safety, an overloaded machine can be dangerous to personnel, or could break down and bring operations to a costly halt.

In operational terms, unloaders need to run at optimum speed to minimize ship turnaround times, while also controlling the rate of delivery of materials to the dockside facilities. Live load data can allow operators to calculate the amount of cargo moved, the time to completion of each operation, the number of trucks required for onward shipment, etc.

There is also a distinct commercial requirement for effective monitoring, as the value of many dry bulk cargoes is calculated from its weight.

Real-time data from the unloaders is collected by having sensors monitoring the critical variables — in this case the torque on the drive shafts, the speed of the motors and the drive power.All of this data fed back to the control system can help in deriving load values on conveyors, stress and potential overload in unloading systems, and weight of bulk product moved.

However, torque data can be hard to collect, with traditional technologies introducing as many problems as they solve. Because the shaft is rotating, wires attached to it would wind up and snap, so a special way of monitoring it is required. The usual solution is to use slip rings, but these are expensive, difficult to set up and far too delicate in use for dockside applications.

An emerging technology that is increasingly being integrated into unloaders is wireless, non-contact digital torque monitoring, an area of specialism for Sensor Technology. These sensors measure the work being done by the motors and drive shafts of the unloaders and the data is automatically and instantly converted into cargo weight figures.

With over 20 years of research and development into digital non-contact torque monitoring, Sensor Technology is at the forefront of this technology. Operating out of the heart of Oxfordshire, Sensor Technology is an acknowledged leader in the manufacture of quality torque measurement solutions and wireless load sensors. It has a global network of distributors assisting sales, and a network of world-renowned technical experts assisting in the development of technology.

Sensor Technology’s non-contact torque monitoring transducer,TorqSense, is based on the patented technology of measuring the resonant frequency change of surface acoustic waves (SAWs) generated by rotating shafts. It’s a proven technology that has solved torque measuring challenges in a host of industries.

TorqSense torque sensors use two tiny SAW detectors made of ceramic piezoelectric material containing frequency resonating combs. These are glued onto the drive shaft at 90° to one another. As the torque in the rotating shaft increases one comb expands and the other contracts proportionally to the torque being applied. In effect, the combs act similarly to strain gauges, but measure changes in resonant frequency.

An adjacent pickup emits radio waves towards the SAWs, which are then reflected back. The change in frequency of the reflected waves identifies the current torque. This arrangement means there is no need to supply power to the SAWs, so the sensor is non-contact and wireless.

Applied to mechanical ship unloaders, the technology is bringing distinct advantages. A process that was once regarded as very difficult to monitor can now be optimized for the highest levels of productivity with the lowest cost. Not only does it offer many benefits for conveyor dry bulk unloading, it has also been adapted by Sensor Technology recently — in the form of the wireless LoadSense transducer — for use with straight-line load monitoring, such as is required by cranes and hoists as they lift cargo to and from ships. This means that all cargo handling techniques used in any given situation can be monitored by the same system, which will lead to significant savings in management time and costs as two or more reports do not have to be integrated.