Siwertell ship unloader: outstanding performance with consistently high through-ship capacity
The Siwertell ship unloader is designed to transfer dry-bulk cargo from ship to shore in the most efficient manner possible. Equipped with Siwertell’s totally-enclosed screw-type technology, the ship unloaders deliver high rated capacities, excellent through-ship performance and low environmental impact. The unloaders can handle almost any dry bulk material and the same machine can be used for different materials without requiring changes to the equipment. All Siwertell ship unloader systems are tailor-made with each customer’s operation in mind.
The counter-rotating inlet feeder was invented by Siwertell to increase the efficiency of cargo pick-up and the filling factor of the vertical conveyor. It gathers material from below the cargo surface in the ship’s hold to minimize dust creation and then feeds it into the vertical screw conveyor. Different designs of feeder may be used to optimize the unloading performance depending on the material being handled.
The vertical conveyor is a screw-type device which elevates bulk material from below the cargo level in the ship’s hold up to the horizontal conveyor. The totally-enclosed vertical conveyor is built up from standard screw sections, outer tubes and intermediate bearings. It is mounted in a robust supporting steel structure.
Siwertell designed the unique Outer Diameter (OD) bearing to achieve a continuous screw flight for the vertical conveyor without any interruptions. A continuous screw reduces power consumption and minimizes the risk of material getting stuck in the tube.
Heavy items such as pay loaders and excavators are often used in the holds to assist the unloader during the final clean-up phase. A wire rope hoist, installed on the horizontal arm, is used for lifting equipment in and out of the hold.
The horizontal conveyor is normally a screw-type conveyor. Mounted on the horizontal boom steel structure, it receives bulk material from the vertical conveyor via an enclosed transfer chute. It then transports material to a vertical discharge chute in the center of the slewing turret. For some applications an enclosed belt conveyor is used instead of a screw conveyor.
The electrical system is installed in an insulated electrical housing equipped with a heating fan and an air-conditioning unit. It is made up of elements such as low voltage switchboards with a motor control center, contactors, a programmable logical control-system and the human machine interface.
The unloader can be operated either from the cabin or using a remote control unit directly from the side of the ship’s hold. Both arrangements offer excellent views of the unloading area. The cabin is mounted on an arm at the same level as the horizontal arm and it slews along with the horizontal arm. It is fully-insulated and equipped with a heating fan and an air-conditioning unit to provide the operator with a comfortable work place, even in extreme weather conditions.
Ship unloader performance
Siwertell unloaders offer a wide range of rated capacities from 200t/h to very high rates of more than 3,000t/h. However, the true measure of their excellent performance is their through-ship capacity; the time it actually takes to completely discharge a vessel. In addition, outstanding performance should be linked not only to unloading rates and efficiency in the unloading process, but also to the ability to unload sensitive cargoes without degradation of the cargo and with limited power consumption.
Ship unloader tailored features
Siwertell ship unloaders are equipped with our unique inlet feeder that ensures efficient material pick-up into the vertical screw conveyor, providing consistently high unloading capacities. Conveyors are available in different sizes depending on cargo material and the capacity required. Optionally, a clean-up unit can be used at the vertical conveyor to facilitate final hold cleaning procedure. Unloaders can be fitted with outlets to enable the direct discharge to trucks and rail wagons or for discharge onto any type of jetty conveyor.
Ship unloader: cost efficiency
Siwertell unloaders offer important cost savings through:
- Low energy consumption
- Easy operation
- Minimal material spillage
- High capacity resulting in low shipping costs
- Lightweight design