Venturi eductor with flow restrictor

A venturi eductor comprising a flow passage (2; fig 2) for a first liquid, a dispensing passage (3; fig 1) with an opening (4; fig 2) into the flow passage to allow a second liquid to be drawn there through and into the first liquid flowing through the flow passage, and a flow restrictor 6 in the dispensing passage wherein the flow restrictor 6 comprises a body with a plurality of apertures of varying size, such that the body is movable between a first position in which a first of the apertures is disposed in the path of the second liquid, and further positions in each of which a further of the apertures is disposed in the path of the second liquid. The flow restrictor controls the flow of second fluid and thus the concentration of second fluid within the first. Ideally, the flow restrictor comprises a control member 34 which is linked to the aperture body 6 such that rotation of the control member causes the aperture body 6 to rotate and an aperture of a chosen size to be aligned with the second fluid inlet 50 and the opening. The flow restrictor may further comprise a seal 27, lock means 54, 55 and lock release means 60.