Abstract: The invention provides means for controlling the flow of fluids such as parenteral fluids. It comprises a body and flexing means. The body defines a passageway with opposed flexible walls which can be held in contact throughout their cross-section except for a limited region of which the cross-section varies along the body. The limited region may be formed by tapered grooves in the walls. The flexing means retains the body flexed so that the walls thereof are held in contact over a localized area of limited axial length, due at least partly to the internal stresses set up in the body arising from its flexure. The body is movable lengthwise relative to the flexing means to alter the position of the localized area and thus to alter the rate of fluid flow through the body.

Abstract: Apparatus for administering liquids such as blood or saline solution comprises a readily collapsible but substantially inextensible container with a duct through which liquid can leave the container. Take-up means is provided to restrict the volume of that part of the container communicating with the duct, and referred to as the operative part. The take-up means is adjustable to vary the volume of the operative part. Calibration means is provided to enable the volume or the changes in volume of the operative part to be measured. In one type of construction the duct leads to a junction between a liquid inlet which may be connected to a source of liquid, and a liquid outlet, such as a terminal connector connectable to a needle, a catheter or the like.