An invention is provided for detecting an endpoint during a chemical mechanical polishing process. Mounted on the projection is a thermostatic operating element, which operates to control the valve when wax inside the thermostatic operating element is heated. The clamping mechanism involves a screw activated clamping block that moves up or down or involves a sliding mechanism that moves at least two clamping blocks in a sideways movement. The cooled second oxidized gas stream can be further treated in a spent acid recovery plant or a sulfur recovery unit.