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Publication of BE658536ApublicationCriticalpatent/BE658536A/xx
E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
E21D15/14—Telescopic props
E21D15/44—Hydraulic, pneumatic, or hydraulic-pneumatic props
E—FIXED CONSTRUCTIONS
E21—EARTH OR ROCK DRILLING; MINING
E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
E21D15/50—Component parts or details of props
E21D15/51—Component parts or details of props specially adapted to hydraulic, pneumatic, or hydraulic-pneumatic props, e.g. arrangements of relief valves
E21D15/515—Particular fluids not covered by any chemical subdivision
F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
F16J—PISTONS; CYLINDERS; SEALINGS
F16J10/00—Engine or like cylinders; Features of hollow, e.g. cylindrical, bodies in general
F16J10/02—Cylinders designed to receive moving pistons or plungers