PCT No. PCT/FI84/00038 Sec. 371 Date Jan. 7, 1985 Sec. 102(e) Date Jan. 7, 1985 PCT Filed May 17, 1984 PCT Pub. No. WO84/04804 PCT Pub. Date Dec. 6, 1984.The invention concerns a flow regulator, intended for gaseous substances, in particular for air in air-conditioning and ventilation installations, for maintaining the volumetric flow of the gaseous substance at desired magnitude with sufficient accuracy when the differential pressure acting across the flow regulator varies within desired limits. The flow regulator comprises an envelope and a regulating member disposed in the flow passage confined by the envelope. The flow regulator is provided with limiter members for limiting the differential pressure range of the flow regulator, said limiter members being disposed to restrict the movement of the regulating member. The limiters are adjustable and/or self-adjusting. The flow regulator has a scale for setting the limiter members.