What are the top types of Port Cranes?
The use of cranes is believed to date back to 3000 BC. The earliest known crane, called a “shaduf,” was used to draw water from lakes and rivers to irrigate Egyptian farmland. It consisted of a pole with a bucket at one end, balanced on a fixed support.
Simple Cranes
The simplest cranes consist of levers and pulleys.
Ancient cranes used single-arm cranes with a fixed angle to lift heavy objects. Today, modern cranes can operate at angles ranging from a few degrees to near vertical, used for lifting a wide variety of heavy objects, from construction sites to warehouses to seaports.
Both stationary and mobile cranes can easily move goods from one place to another. Cranes are typically balanced to prevent them from tipping forward when lifting heavy objects. Some cranes have protruding arms or outriggers that are firmly anchored to the ground to help maintain stability and distribute weight evenly. This article will focus on cranes used in seaports for lifting heavy objects such as boxes, machinery, vehicles, and containers. How are containers loaded and unloaded?
Cranes play a vital role in lifting and stacking heavy objects in port yards. They are also used to load heavy objects onto ships.
Take the gantry crane, a common sight in seaports, as an example. It has a main support frame called the gantry, which is a long boom extending above the hull. Spreaders and the operator’s cab are suspended above the main frame, where the operator controls the crane. The crane spreader is a movable clamp used to grab containers and lift them onto or off the ship.
How are containers loaded and unloaded?
Port cranes have trolleys that move along dock tracks. There are also tire-mounted gantry cranes. After containers are lifted from the ship, they are placed on trucks or the ground and then transported to their designated locations by cranes or forklifts. Port cranes are typically designed to lift loads ranging from 40 to 120 metric tons.
A device called a “spreader” is used to secure the four corners of the container for lifting, loading, and unloading operations. The device is connected to the four corners of the container via a screw locking mechanism.
The spreader is designed for lifting 20-foot, 40-foot, or 45-foot containers. A single spreader can lift these containers individually or simultaneously lift two 20-foot containers. A dual spreader can lift a single container at a time or simultaneously lift 20-foot, 45-foot, or 40-foot containers. Spreaders are used on various types of cranes to handle containers.
Crane can be diesel-powered or electric-driven. However, most modern cranes are electric-driven. Independent, high-powered motors drive the boom, beam, trolley, and hoisting mechanism.
Crane used in seaports are generally divided into quay cranes and yard cranes. As the name suggests, quay cranes operate at the quayside, while yard cranes are located in the container yard inside the port.
Dock Cranes
When cargo ships are docked at the quay, large cranes are used to lift containers and other cargo from the ship to the shore, or from the shore to the ship (loading and unloading). Cranes used for this purpose are generally called dock cranes. Depending on the specific circumstances, they are also called ship-to-shore cranes or shore-to-ship cranes (STS cranes).
Modern mega-shore cranes are primarily classified according to their ability to lift containers from large vessels transiting the Panama Canal or other ports.
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Ship Cranes
Low-head shore cranes are typically used at docks near ports and airports. These cranes have low, fixed jibs. High-head cranes have jibs that can be raised for berthing or assisting fully loaded vessels through the canal.
Let’s look at some of the main types of piling cranes.
Panamax Cranes
Panamax cranes are used to lift containers onto large vessels large enough to transit the Panama Canal. Most of these cranes have jibs that can extend up to 30 meters and reach a height of approximately 38 meters.
Depending on whether the lifting operation is single-arm or double-arm, Panamax cranes have lifting capacities between 50 and 65 tons. Its lifting speed can reach 125 meters per minute, and the trolley travel speed is approximately 180 meters per minute, which is very fast.
Post-Panamax Cranes
Post-Panamax cranes are used to load and unload containers from large ships that are often too large to pass through the Panama Canal. Naturally, these cranes have a greater lifting capacity, with a horizontal span of up to 45 meters and a lifting height of approximately 35 meters.
Like Panamax cranes, it can lift approximately 50 tons of cargo in a single lift, and up to 65 tons in a double lift. Its lifting speed can reach 150 meters per minute. The trolley speed of a post-Panamax crane can reach 210 meters per minute.
Post-Panamax Giant Crane
With the growth of global freight volume and the increase in ship tonnage, port cranes must adapt to the ever-increasing freight loads. Ports compete to attract freight volume and increase revenue. In this situation, ports cannot afford delays or cargo backlogs. To remain competitive, ports must always be equipped with more efficient and faster operating equipment.
Post-Panamax giant cranes are used for loading and unloading containers from large ships. Their operating radius is approximately 50 meters, and their lifting height is approximately 40 meters. Their lifting speed can reach 175 meters per minute, while the trolley speed can reach 240 meters per minute.
Bulk Cargo Handling Cranes
Bulk cargo handling cranes are equipped with two buckets or hooks for grabbing bulk cargoes such as coal, minerals, grains, and other materials for loading and unloading operations. The grabbing mechanisms used in these cranes are specially designed to handle specific products and operating conditions.
Gantry Cranes
Fixed gantry cranes are typically located above the work area for lifting and moving containers or other types of cargo. Mobile gantry cranes move on rails or wheels, positioned above the object to be lifted and moved.
Floating Cranes
These large, fixed cranes are mounted on floating platforms for loading and unloading containers from cargo ships. These floating platforms are located alongside the vessel for lifting heavy objects.
Tower Cranes
Tower cranes consist of a fixed base, a vertical mast, and a jib mounted on a rotating mechanism. Counterweights are used to balance the jib. The crane operator’s trolley is typically located on the jib, and the crane is controlled via the trolley. Winch and hook moving along the boom are used to lift heavy objects.
Container Yard Cranes
A crane used to move containers and other cargo within a port yard is called a container yard crane. They are used to move loaded or empty containers onto trailers for inland transport or to the dock for loading onto cargo ships. Different types of container yard cranes are used to stack containers within a port yard.
Forklifts and Container Cranes
Forklifts and container cranes are commonly used container handling machinery used to rearrange or stack containers within a yard. They are also used to load and unload containers from trucks or railcars.
Telescopic Container Stackers and Forklifts
These cranes and forklifts typically consist of a telescopic boom, which is hydraulically controlled and mounted on a vehicle. Spreaders at the end of the boom are used to grab containers and lift or lower them.
Deck Cranes
Some small vessels are equipped with deck cranes for lifting containers from one shore to another. This is very useful in ports without cranes or with a small number of containers.
Modern cranes are designed to achieve maximum speed and efficiency. They are used to complete loading and unloading operations in the shortest possible time while ensuring the safety of workers and infrastructure.
Multiple Deck Cranes
Multiple cranes can be used to complete container loading and unloading operations on cargo ships on a schedule. Skilled port crane operators are key to achieving this.
European crane manufacturers are leaders in port crane production. The German-Swiss joint venture giant Liebherr, as well as Finnish-based KONE and Kalmar, are leading port crane manufacturers.
