Colour rings as orientation aid
MÜLHEIM PIPECOATINGS GmbH (MPC) - the world’s leading specialist in internal and external coating of large pipes – and Teknos Deutschland GmbH look back at a partnership that has endured many years. Together, numerous projects have been carried out and several tonnes of internal and external pipe coating have been produced and processed. The Trans-Adriatic Pipeline Project (TAP) entailed a new challenge and together with Teknos Germany, MPC developed a solution from the selection of the correct pipe marking colour to the optimal application onto the large pipe.
Admittedly, when a coated pipe is decorated with one or several coloured rings at three-metre intervals, there is a visual effect. Only that these coloured rings probably do not serve decoration purposes, but likely must fulfil a more profound role. Christian Balkenohl, Head of Production and Maintenance, from MPC knows the reason: “We mark pipes with up to five coloured rings for clear identification at building sites and ports.”
In South Stream, each point of destination was marked by a colour, while in the TAP each wall thickness and thus also the point of destination was marked by a colour. Although this information could also be obtained via the barcode, this is simply not always feasible. And, in addition, orientation is simpler using colours.
Automatic coloured ring sprayer
Previously, these rings were applied by hand in that a worker simply held a paint roller against the rotating device for inspecting the rotating of the pipe. But the TAP project has other requirements.
“The customer wanted not just five rings at intervals of three metres, but also a clean and sharp-edged contour", says plant engineer Tobias Neukirchen. However, assigning five employees to the play of colours was simply too complex for MPC. Quite apart from the fact that they would probably not have managed to create the clear colour picture required.
Hence, in autumn 2015, initial considerations were given to creating an automatic coloured ring sprayer. Finally, on 5 December 2015, a mechanism designed by MPC and manufactured by a specialist in equipment and systems used for material conveyance and application with five variably positionable cans was installed on an existing rotating device.
For the current order they are installed at intervals of three metres and are supplied with water-based paint by means of two printing colour containers each holding 20 litres.
The reason there are two is so as not to lose any time in the event of a colour change. While the parts for the mechanism are standard, the paint caused a major headache.
“Normal paint does not adhere to PE and PP coats, so we first held detailed discussions with one of our long-term suppliers, Teknos,” explains Christian Balkenohl. Since the customer also insisted on RAL colours, some time and tests went by before the right colour was finally found. ln close cooperation between MPC, Teknos and the application system manufacturer, the suitable colour was then identified on a test facility.
The water-based product NORDICA EKO 3894 (previous product name: GORI 894) - which is normally used in the field of industrial wood coating - was used. However, for marking the pipes, NORDICA EKO 3894 impressed thanks to its good adhesion, fast availability, particularly economical productiveness as well as feasibility in any RAL shade desired.
Good and simple system
Further important steps prior to commissioning the system were configuring a clean spray pattern and controlling the pressure tanks, which supply the five spray guns with up to 7 bar of supplementary and atomised air. Each gun has its own configuration. In advance, cans had been sought that are able to produce the desired sharp-edged colour image and the requisite spraying width.
“Even if all that sounds a bit complicated when described, we wanted a good yet simple system without a lot of electronic bits and pieces", says Tobias Neukirchen, who supervised the introduction of the system as project manager. And MPC now has exactly that in use on the rotating device: a mechanism that applies the rings exactly and precisely, that can apply only three rings as well as five and that - if desired - would even be suitable for longitudinal stripes. As was said previously, not for decorative purposes, but as an orientation aid. Even so, they do look good, the pipes with their coloured rings.