| 摘要 |
<p>Fluid flow rate is controlled by passing it through a collapsible conduit (22) and arranging that the pressure head driving the fluid through the fluid path downstream of the collapsible conduit is sufficiently smaller than the pressure head driving the fluid through the collapsible conduit that the conduit is maintained in a partially collapsed condition. This decouples the upstream and downstream parts of the path and prevents downstream pressure variations being propagated to the upstream part. Variations in the upstream pressure head, e.g. in a supply reservoir (10), can be compensated by transmitting those pressure variations also to an enclosure (24) around the collapsible conduit, thereby keeping the transmural pressure difference constant. An adjustable height chamber (30), partially filled with liquid, in the pressure compensation transmission path enables the flow rate to be varied. The invention is particularly applicable to intravenous infusion sets for controlling the infusion rate.</p> |
