A 72 tonne overhead crane for reel loading and unloading has been installed in a new marine cable factory by Street Crane Company. JDR Cable Systems produce multi-core umbilical cables for offshore oil and gas platforms and will use the crane to ensure high volume production from a new vertical lay-up machine (VLM).
The factory crane package includes an 11 metre span double girder crane with a 72 tonnes safe working load and a custom-built VX hoist, operating on a 30 metre long freestanding gantry system. Unusually, the gantry was installed prior to the erection of the building shell and the completed crane was used in the assembly of the carrousel at the core of the VLM. Once the carrousel was installed, end-stops were fitted to the gantry to limit crane travel and protect the top part of the machine.
As an integral part of the factory production process, the crane is engineered for safety and reliability. A radio remote control system allows the crane operator to select a position of clear visibility and maximum safety, a push-button pendant back-up control gives continuity in the event of any radio failure.
Reflecting the number and frequency of expected heavy lifts, the hoist mechanism is rated M5 which allows up to 240 motor starts per hour. The VX hoist was designed and built specifically for this application and includes inverter control for very fine hoisting speed adjustments with smooth step-free speed changes while assuring load stability. A custom coil grab is installed for cable drum handling. For final load positioning, the hoisting speed can be reduced to just 10 per cent of its maximum 2.6 metres per second transfer speed.
Chris Lindley-Smith, Street Crane’s sales director commented, “It is relatively unusual for an overhead crane to be pre-installed and used in the equipment build phase, the rare exceptions being power stations and aluminium pot lines. At JDR Cable Systems, the crane is a key part of the manufacturing process making an important contribution to the productivity of this capital intensive and highly specialised manufacturing operation.”
Marine cables are essential to the oil and gas industry. The VLM enables power, control, instrumentation and communication/data cables to be raised from reels and twisted with packing and support material to form the bespoke umbilical. A subsequent process adds the final sheath and armour that protect the cables from the elements and mechanical damage.