container crane
A container crane (also known as a portainer, container handling gantry crane, quay crane, ship-to-shore crane, ship-to-shore gantry crane or a STS crane) is a large dockside crane in the form of a specialised type of gantry crane used to load and unload container ships, and only seen at container terminals. The term Portainer is a registered trademark of Paceco Corp. who is generally believed to have delivered the first Container Crane to a marine terminal in Alameda, CA in the 1960s. Container cranes have a special lifting device called a spreader (also known as Expandable Spreader) for loading and discharging of containers. The spreader has four or eight (for twin 20 foot container lift) twistlocks which lock and unlock into the cornercastings of the containers and can be used in 20', 40', or 45' positions depending on the size of the containers. Horizontal gantry rails[1] and their supporting structure are cantilevered out from between the frame uprights which are spaced to allow containers to pass lengthwise between them. The gantry rails project over the quayside and also over the width of an adjacent ship allowing the hoist to lift containers from the quay and move out along the gantry rails on its trolley to place the containers on the ship. The whole crane runs on two rails so that it can traverse along the wharf (or the dock) to position the containers at any point on the length of the ship.
Types
There are two common types of container handling gantry crane: high profile where the boom is hinged at the waterside of the
crane structure and lifted up in the air to clear the ships for navigation; the second type is the low profile (goose neck) type
where the boom is shuttled/pulled towards and over the ship to allow the trolley to load and discharge containers. Low profile
cranes are used where they may be in the flightpath of aircraft such as where a container terminal is located close to an
airport. The high profile cranes are the taller of these which are shown in the pictures
Designers and manufacturers
Amongst the major designers and manufactures of these cranes are Liebherr Container Cranes , Kalmar
Industries , Zhenhua Port Machinery Company (ZPMC),
TCM Corporation, Noell, KCI Konecranes, Kocks, IMPSA, Paceco, Mitsubishi, Mitsui Hyundai and
Shanghai based ZPMC is the worlds largest manufacturer of container cranes, they often deliver the portainers fully assembled
as shown in the picture to the right. The heavy lift ships are converted tankers with the cranes welded to the deck of the ship.
The cranes are 103 metres high with the boom up or 73 metres with their booms down. Each crane weighs 1,850 tonnes and costs
about USD10 million each. From order to delivery takes about two years with ZPMC being able to construct 125 cranes at one time
at their manufacturing facility on the Yangtze River, Shanghai, China.[2]
Sizes
Container Cranes are generally classified by their lifting capacity, and the size of the container ships they can load and
unload containers. A Panamax crane can fully load and unload containers from a container
ship capable of passing through the Panama Canal (ships of 12-13 container rows wide). A Post-Panamax crane can fully load
and unload containers from a container ship too large (too wide) to pass through the Panama
Canal ( normally about 18 container rows wide). The largest modern container cranes are classified as Super-Post
Panamax(for vessels of about 22 container rows wide and/or more). A modern container crane capable of lifting two 20 foot
long containers at one time will generally have a rated lifting capacity of 65 tonnes from under the Spreader. Some new cranes
have now been built with 120 tonne load capacity enbling them to lift up to four twenty foot or two forty foot long containers.
Cranes capable of lifting six twenty foot containers have also been designed. Post-Panamax cranes weigh approximately 800-900
tonnes while the newer generation Super-PostPanamax cranes can weigh 1600-2000 tonnes.
Operation
The crane is driven by an operator that sits in a cabin suspend from the trolley. The trolley runs along rails that are
located on top or sides of the boom and girder. The operator runs the trolley over the ship to lift the cargo which generally are
containers. Once the spreader latches (locks) on to the container with the Spreader, the container is lifted and moved over the
dock and placed (discharged) on a truck chassis (trailer) to then be taken to the storage yard. The crane will also lift
containers from the chassis to store (load) them on to the ship.
Lorries, Automatic Guided Vehicles ( AGV's ) and straddle-carriers, can manoeuvre underneath the base of the portainer crane, and collect the 'boxes'.
They are designed to allow rapid cargo operations between the dock and storage yard.
Power
The cranes are powered by two types of power source; by diesel engine driven generators which are located on top of the crane
or by electric power from the dock. The most common is by electric power from the dock (also known as shore power) in which case
the electric source is AC which can be from 4,000 up to 12,000 volts.
References
External links
See also
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