CHETRA Mechanical Seals for the Pulp and Paper Industry
Thorough and “leakage-free” sealing of latex mixes
One of the largest Finnish paper manufacturers had problems with sealing of latex mixes in the kitchen coatings. This specific application in the paper production is one of the most technically demanding, difficult tasks in the seal industry.
Because of excessive leakage with the seals used so far, the most important latex pumps were refitted with CHETRA mechanical seals style 821 with barrier fluid system.
Service Lives of Seals in Pulpers at a New Level
CHETRA was asked for a solution, because some paper factories, domestic and abroad, had trouble with the service life of seals in pulpers.
Special requirements ensue from heavy shaft deflections, effected by the lateral arrangement and the design-related, rather far distant position of the bearing to the seal. Very often the propeller runs above the level of the material and hits it. The stock consistency is also difficult to cope with, which is often 5 % bone dry and higher. A stationary seal of CHETRA mechanical seals series 201, designed for these special requirements, met all seal-technically demanding requirements and solved the problems. Service lives of 10 years (!) are achieved.
Standardization and Continuous Improvement
Sealing technology was put on a new, standardized basis in Austria’s largest corrugated board factory. Essentially, all relevant areas of application in the factory use only three CHETRA mechanical seals:
Style 700 mechanical seal with single metal bellows, up to 2 (2.5) % bone dry.
Style 208 N single mechanical seal in stationary design up to 3.5 % bone dry without flushing.
Style 807 double mechanical seal, double-balanced, for higher barrier pressure or pressureless quench for operation; bone dry > 3.5 %.
Above and beyond the aforementioned improvements, CHETRA provides the Austrian factory with a continuous improvement process. This means that the seals meant for overhauling or repair are in a continuous process of survey and analysis to consistently guarantee improvements and optimizations for product, operation and background conditions.