SATRA STD 401 Compression set apparatus

Constant strain

This apparatus is designed for constant strain compression set testing of rubber and rubber-like materials at room temperature and elevated temperatures.

This is achieved by placing each of three discs between two compression plates screwed together until stopped by a distance piece. The apparatus consists of a stack of alternate compression plates and distance pieces allowing five rubbers to be tested at once. They are all compressed in one operation by turning a single hand nut on a centre bolt.

Test pieces are held compressed for the specified time and, after release and a short recovery period, the new thicknesses are measured. The compression set of the material is the amount of compression retained, expressed as a percentage of the original thickness of the disc.

To facilitate the hand tightening, the base of the apparatus is made to fit into a holder screwed to the bench, but it is easily removed from this if the apparatus needs to be placed in an oven for a high temperature test. Alternatively, the base of the instrument may be screwed to the bench if used for room temperature tests only.