Shiploaders

28 April 2020

Shiploader

In recent years, there has been an increase in the volume of transshipment through seaports of Russia along all the seaways: the Arctic, Baltic, black sea and Far East.

Existing ports began to grow and develop, and new mega-projects were implemented, equipped with the latest and specialized technic and technology. And for each specialized marine terminal, one of the key positions is a ship loading machine.

Depending on local conditions, vessels with a very wide range of cargo capacity – from 5,000 DWT to 120,000 DWT - can be loaded in Russian ports. Vessels of large displacement often cannot be loaded at the berth, and stand on the roadstead, taking cargo from small shuttles with their own grab cranes or through intermediate warehouses-barges equipped with grab cranes for unloading shuttles and continuous ship loaders for loading ocean bulk carriers. Also, most ports are characterized by a short navigation period because the ice environment, which is further reduced by strong wind (at least in gusts of more than 14 m/s, loading stops, even a single gust can lead to an accident and serious damage to the loader) and precipitation (snow, rain, hail are unacceptable when mineral fertilizers and grain loading is going on, sulfur and coal are not sensitive to precipitation). All these circumstances lead to the demand for the accumulation of large volumes of material in the warehouse in the immediate vicinity of the berth, and high productivity of the ship loading machines used – there are figures up to 6 000 t/hour, so that in the short hours when shipment is possible, to have time to fulfill the annual plan for cargo turnover.

Ship loading machines are classified according to several criteria.

Depending on the overall layout, ship loading machines can be slewing or non- slewing.

Slewing grain machines often have a loading chute as a rigid metal (sometimes telescopic) pipe with a distribution device (trimmer) at the end.

Non- slewing (also called coordinate) shiploaders provide access to a given point of the hold by moving the entire machine along the pier (the first coordinate) and moving the loading chute in a cross direction (the second coordinate) by moving along the boom of the shuttle carrying the loading device (changing the length of the boom conveyor and the point of dumping material with the same length of the boom), or by telescoping the boom (the unloading device is always at the end of the boom, but the length of the boom changes.

According to the method of feeding the material , it can be dumped into the bulk hopper of the ship loader from a high belt loop loader when the mooring conveyor is open and goes over the surface (which is more typical for such non-precipitation sensitive materials as coal, ore or sulphur) ,

or the mooring conveyor is located inside a high covered gallery that protects the cargo from a wind, rain and snow. Then the shiploader is equipped with a rear boom that goes into the mooring gallery if the gallery is located behind, or an auxiliary conveyor is located inside the portal - if the mooring gallery passes under the portal.

Slewing grain shiploaders also have a high-performance bucket elevator that allows to lift the grain to a significant height (up to 30 meters with a capacity of up to 12500 t/h) and ensure further movement of grain to the boom conveyor by gravity.

Further used unloading devices can be free fall (eng. "free fall"), in the form of telescopic pipes inserted into each other or metal / plastic cones, or the "Cleveland cascade" type, when each subsequent cone has a displacement of the direction axis of the material flow, and moving from cone to cone, the product constantly changes direction and loses speed, which allows to avoid destruction, for example, of mineral fertilizer granules (when free falling from a height of 20-25 meters, they gain unacceptably high kinetic energy) and reduce dusting.

Outside, as a rule, the unloading device has a protective cover, which is collected in folds when collecting the unloading device, and when the unloading device is extended, and prevents precipitation from entering the flow of material and dust emission from the unloading device.

At the end of the discharge device can be simply an elastic "skirt", "apron" of rubber or plastic, closing the gap between the edge of the loading chute and the upper point of the material in the hold and preventing dusting or trimmer as a mechanical device that allows to reach places in the corners of the hold, below deck space. A local aspiration system can also be installed at the end of the discharge device to reduce dusting.

Already existing terminals undergoing major repairs, replacement of worn-out and delivery additional shiploaders are faced with the problem of technological inability to perform the major assembly/disassembly operations: the pier has no access for extra-large and heavy-load assembling equipment (cranes and tracks), didn’t keep the load outside of shiploader’s rail and occupied by working on shiploaders (almost always current activities couldn’t be stopped), the surrounding area is occupied with conveyor galleries, warehouses and railway train tracks. If the ship loading machine is not slewing one and the rails along the berth are not extended from the sea side to a specially planned (or accidentally formed, which is unlikely) rear maintenance site, any major repair work with the boom is possible only with the use of floating cranes with a high load capacity (which are always very expensive and very busy ), and the only way to deliver a new ship loading machine is to deliver it as assembled one. It requires the installation of the machine in the port of shipment, the use of special vessels with their own cranes on board and the development of a project for rolling out the ship loading machine to the berth. The difference in the cost of installing a ship loading machine at the recipient's berth and delivering it as assembled one could be up to $ 1 000 000. In addition, sometimes (that is, over time - almost always) there are serious accidents at the terminals – either the boom of the ship loading machine strikes the ship, or the ship strikes the boom, but in any case the arrow requires urgent repair, and wait for the floating crane year (or even a month) is a completely unacceptable.

On the other hand, if the terminal is ready to accept these costs and risks, it can save on expensive port territory, reduce the length of conveyors due to a denser line-up, and can put the resulting ship loading machine into operation in a short time (sometimes 1-2 months).

Since modern projects of marine terminals must take into concideration many different (sometimes contradictory) factors, each ship loading machine becomes a unique product, only the development of which can take more than six months.