DEPAC special mechanical seal for the mining industry

The Problem

Extreme conditions prevail in tunnel construction and mining. The tunnel boring machines used there are subjected to massive stresses. The mechanical seal solution requested by the customer envisaged the mounting of the entire head system. In addition, segment-wise spraying of the cutting head at a pressure of up to 70 bar was foreseen in the area of the tunnelling attack.

The DEPAC solution

The DEPAC special solution was expanded into a comprehensive solution with different functions. The interior and exterior seal pair now seals off the water pressure. The water is distributed to the circumference of the rotating part via 16 boreholes in the intermediate space between the two seal face pairs. A spring-loaded segment ensures that only 30 percent of the boreholes are ever open at any one time. The fluid thus always escapes in the same angle range.

In addition, the mechanical seal was mounted with an axially movable housing cover. It allows "blind" installation with axial tolerances of up to +/- 2 mm.