Delft University of Technology
Faculty Mechanical, Maritime and Materials Engineering Transport Technology
R. Gratama Design of a telescopic boom conveyor for a pontoon crane
Engineering Assignment, Report 2005.TL.6977, Transport Engineering and Logistics.
At smaller dry bulk terminals, there is a demand for a multifunctional crane that can be used for different kinds of jobs. The crane should be able to load and unload ships directly overboard, also at the entrance of the port for lightening vessels. Besides that, the crane must be capable of unloading dry bulk directly onto the terminal, even when there is no seaside equipment available at the terminal. For this purpose, a design has been made, based on the existing Gottwald HPK360 pontoon crane. To give it the desired multifunctional characteristics, a telescopic boom conveyor has to be installed onto this pontoon. This telescopic conveyor should have a minimum length of 40 m and a maximum length of 60 m. It has to be designed for unloading coal at a rate of 1800 tons per hour. The 50 tons grab crane of the HPK360 is used to position the boom conveyor. The telescopic boom conveyor designed in this assignment has got the following characteristics:
The rubber belt has a width of 1400 mm. The belt speed will be 3,35 m/s. This conveyor belt system is widely sufficient for transporting coal at a rate of 1800 tons per hour.
The conveyor belt is installed on top of two trusses of 40 m each. The smaller inner truss is placed inside the other truss. By sliding it out, the total length of the telescopic boom conveyor can reach 60 m. The boom conveyor totally has a mass of 40 tons, so that it can be handled by the HPK360's grab crane.
On the pontoon side, the telescopic boom conveyor is hung up in a specially designed structure, so that it stays exactly in its vertical position, while the pontoon rotates freely in the water. On the other side, a foldaway support is mounted underneath the boom conveyor, so that it rests solidly on the quay wall.
A steel frame is welded on top of the telescopic boom conveyor. The grab crane can grab this frame, so that the boom conveyor can be hoisted. Despite the extra mass of the newly applied equipment, the pontoon will still be stable under all circumstances.
The conclusions are that the telescopic boom conveyor designed for the existing harbour pontoon crane does satisfy the requirements and restrictions that were stated in advance. The telescopic boom conveyor can transport 1800 tons of coal per hour over distance of 60 m. The crane driver operating the pontoons grab crane can handle the boom conveyor from his cabin. The extra equipment does not affect the current characteristics of the HPK360 harbour pontoon crane.
The design leaves the following recommendations:
The suspension of the telescopic boom conveyor on the pontoon has been designed from scratch. In order to make it lighter, stronger or cheaper to build, the design should be worked out into detail with help of a computer program like ANSYS or Matrixframe.
According to the grab manufacturer, the grab will easily be able to deal with the stresses, caused by hoisting the telescopic boom conveyor. A small real life test program will provide the designer or manufacturer with more information.
Reports on Transport Engineering and Logistics (in Dutch)
