Abstract: An administration set which is suitable for giving an infusion of liquid to a patient by gravity flow from a container of liquid through the set and to the patient comprises a fluid reservoir, a flow regulator and a barostat device which compensates for changes in fluid pressure during the infusion. The fluid reservoir is positioned upstream of the flow regulator and the barostat device is downstream of the flow regulator. In a preferred embodiment a piercing needle connects with a closable tube and injection site which enter the main body of the reservoir by a secure seal. One side of the top of the reservoir extends in a curving manner to be in front of the closable tube and joins an air channel that leads to an airtight chamber which holds the barostat device. An outlet passage leads from the bottom of the reservoir to a collapsible region and descends to an outlet tube which leads via the regulator to the barostat device.

Abstract: A device for controlling the flow of a parenteral fluid, comprises a resilient tubular body of an infusion tube having a flattened portion with two parallel opposed walls. Each wall has a tapering groove, the grooves together defining a longitudinal region of non-contact between the walls of tapering cross-section. Regulating means is provided for flexing a short length of the body about a longitudinal axis of the body so as to urge the two walls together so that the rate of flow is determined by the cross-section of the region of non-contact at said length. Flexure about the longitudinal axis of the body avoids cold-flow of the region of non-contact. The regulating means comprises a support and an operating member longitudinally movable relative to the support, the body being flexed at said length by the co-operation of the support and the operating member. The support is preferably a channel having side walls which define grooves to guide a roller for longitudinal movement relative to the channel.