Russian boiler manufacturer Krasny Kotelshchik bends 90-m long tubes into membrane walls consisting of numerous 180° single bends.

Modern power-plant construction requires powerful machines that can bend challenging materials according to strict specifications. The large dimensions involved require particular structures in the bending process. Here, tube-bending machine manufacturer Schwarze-Robitec designed the CNC 60 DB Twin booster bending machine for the Russian company, complete with 90-m long tube magazine and supporting table featuring a 10 m radius. The machine was recently put into operation.

Modern power plants continuously supply the exact amount of electricity required to the grid. The higher the process temperatures, the higher the level of efficiency. Constantly starting up and shutting down the power plants leads to extreme fluctuations in temperature.

Boiler and power-plant manufacturers aim to maximise the surface area to ensure the highest level of heat transfer. Tubes therefore need to be bent in narrow radii and must fulfil strict tolerance specifications in terms of wall thinning and ovality.

Krasny Kotelshchik bends tube serpentines consisting of numerous 180° single bends in sequence. Each tube section alone is up to 10 m in length. As a result, the corresponding tube system cannot be rotated as a whole for each subsequent bend. Instead, the CNC 60 DB Twin booster bending machine supplied by Schwarze-Robitec bends in both directions using two bending heads. The bending head that is not required moves to the side under the tube system. For this reason, the machine is installed in a pit in the production hall.

Schwarze-Robitec has also set up a supporting table measuring 20 m in diameter above the pit and around the bending head. The tube system is laid out on the supporting table during the bending process. Krasny can thus avoid any unwanted deformations caused by the enormous weight of the tube systems.

For further information www.schwarze-robitec.com