Process for increasing the lifespan of and/or reducing the risk of breakage in the loaded suction roller of a paper machine

摘要

Process for increasing the lifespan of and/or reducing the risk of breakage in the loaded suction roller, e.g. a press suction roller (10) for a paper machine, in which the suction roller (10) is loaded by a nip in such a manner that the stress on the suction roller (10) is changed at least once during each revolution of the suction roller (10). Suction roller corrosion fatigue is improved by setting the suction roller (10) inner surface and suction hole (12) radial openings at least in their inner mouths (12') into lower - that is to say negative - potential in relation to the electrolyte fluid (E) in the inner surface of suction roller (10') and holes (12). An anode electrode or electrodes are arranged in contact with the electrolyte fluid. In between electrodes and the suction roller, a voltage difference for cathode-based corrosion resistance is arranged. Anode electrode or electrodes and current feed to the suction roller is fitted in the axial direction of the suction roller so that sufficient and effective and well spread current density is achieved. As the stressed suction roller surface (10) is stainless steel, the electrical potential (U1) between its inside (10') and anode electrode falls in the area of 0... -700mV (saturated calomel-electrode).<IMAGE>