by means making use of air-suction through an opening closed by the rising liquid

Full Title

Fluid-delivery valves, (for liquid handling B67D; for flushing devices for water-closets or the like E03D) > Self-closing valves, i.e. closing automatically after operation > closed when a rising liquid reaches a predetermined level (float-actuated valves F16K31/18) > by means making use of air-suction through an opening closed by the rising liquid