Liq. drug infusion pump - has rigid housing contg. drug chamber with volume varied by piston like ejector acting with spring unit

摘要

Liq. drug infusion pump has a rigid housing (21) contg. a drug chamber (29) of volume which can be varied by a piston-like ejector (30) acted on by a pre-tensioned compression spring unit (27) fitted to the housing (21). The compression spring unit (27) is formed by a packet of series-connected disc springs (10), pref. identical metal or plastics disc springs which are sepd. by rigid spacer discs (32) and mounted in a concertina housing (28). USE/ADVANTAGE - The pump is an extra-corporeal or fully implantable, opt. once-contg. use pump for long term drug treatment e.g. analgesic therapy, chemotherapy and/or spastic therapy, as well as diabetic treatment. Compared with the pump of DE3507818, the pump has a compression spring unit of sufficient spring extension stroke to ensure constant delivery rate over the drug ejection phase.