Daniel Pettersson; Mikael Lejdeby; Inigo Oz. de Zarate; Mathieu Delamarliere BTH-IMA-EX--2002/C-08-SE, pp. 170. Inst. för maskinteknik/Dept. of Mechanical Engineering, 2002.
This bachelor degree thesis was assigned to us in the fall semester of 2001. The purpose was to redesign a machine for the company Asea Brown Boveri (ABB) in Karlskrona. ABB HVC in Karlskrona is manufacturing high voltage cables. Amongst these the seacables are the largest and most complex. The seacables are heavy naval cables and lies on the bottom of the sea. For these heavy-duty applications the cables need good armouring. The armouring, which is made of steel, needs a corrosion protection layer that is very wear resistant. For this ABB uses industrial bitumen, a form of asphalt. The cables run through a whole production line where the bitumen is applied on the cables at a temperature of 160°C. In this working station the cable armouring wires are winded on the cable and the bitumen is applied.
The present machine is old and needs replacement. In fact the whole AR 50 line is in plan for restoration. This project is to redesign the bitumen application machine and eliminate the present problems. The machine still works, but not satisfying. It is a hazardous workplace when the bitumen is a very dirtying media that sticks to almost everything and it is very hard to clean. It is also very hot and a splash could burn a person. There is also a problem with slag products from the armouring in the surplus bitumen.
The main work has been concentrated on eliminating the larger problems and develop a well working machine that is easy to run and maintain. By applying Fredy Olssons method for product development the work has proceeded step by step. The work started with finding different concept solutions. To simplify the work the machine was divided in four parts, the container for storage and heating, the nozzle for transporting and spreading the bitumen on the cable, the reservoir for collection of the surplus bitumen and to separate the slag particles and the table to hold the distribution rings and the adjustment screw, this to get a better view of all parts and components. These ideas from this phase where evaluated with main focus on the criterions. For al the four units one solution was filtered out for further development.
In the primary construction phase the concepts where transformed in to a whole machine. This phase contains research of components and detail construction of unique parts. Small adjustments of the concepts from the first stage had to be made to create the best solutions.
The machine process can be described shortly. From a main tank outside the building the bitumen is transported to the container where it is reheated to 160°C. From this container the liquid is pumped up through a heated pipe and by a nozzle spread over the cable. On the cable two rings spread the bitumen as a smooth layer on the cable. The surplus bitumen will fall down in to the reservoir where the slag particles are separated. From here the surplus will run back to the container for recycling. To be added the first of the two rings also collects the incoming armouring wires and by the rotation of the cable they are winded around it. This leads to large loads on the construction when the cable traction force is 12 tons.
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