PCT No. PCT/DK89/00044 Sec. 371 Date Sep. 6, 1990 Sec. 102(e) Date Sep. 6, 1990 PCT Filed Feb. 27, 1989 PCT Pub. No. WO89/08750 PCT Pub. Date Sep. 21, 1989.A vortex chamber valve for controlling fluid flow in a pipe system comprising a housing forming a vortex chamber having a curved sidewall, an inlet opening, and an outlet opening; an inlet valve disposed at an upstream side of the vortex chamber inlet opening having a main section and an edge section, wherein the edge section has a deflecting surface protruding away from the main section and towards the upstream side of the inlet valve, the edge section of the inlet valve covers a part of the inlet opening, so that, when upstream fluid levels rise at least up to the deflecting surface, the deflecting surface acts on the inflowing fluid to cause contraction in the inlet opening of the cross-sectional area of the inflowing fluid.