F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
F04C19/00—Rotary-piston pumps with fluid ring or the like, specially adapted for elastic fluids
Diaphragm for alkaline water electrolysis, alkaline water electrolysis apparatus, method for producing hydrogen, and method for producing diaphragm for alkaline water electrolysis