Magnetically-operated tube clamping valve for medical apparatus - adopts fail=safe position upon loss of electricity supply under effect of permanent magnet

摘要

The valve for medical infusion appts. includes pulsative blood pump or dialysis appts. and has an armature (14) scored to clamp the tube (22) or to release the tube (22) via an energising coil (21). The magnetic circuit includes a permanent magnet (17) which is of opposite polarity to that of the armature coil (21) when this is energised. A rare earth magnet e.g. formed from an alloy of cobalt and samarium, or a ferrite magnet can be used, with the force of the magnet (17) ensuring that the armature (14) adopts a fail-safe position, if the supply to the energising coil fails.