Simplified low-cost injection unit for syringe pump, comprising hydraulic devices, e.g. piston-cylinders connected back to back

摘要

This new injection unit (A,B,C,D), consists of at least two hydraulic devices interconnected by a fluid-filled, pressure-resisting line. Preferably the hydraulic device is a hydraulic cylinder (14), with tightly-sealing piston. Alternatively a hydraulic cylinder with a rolled diaphragm and pressure plate, are used. Further variations are described. One of the hydraulic devices performs the duty of a pump and is situated remotely from the patient. The other, close to the patient, is a hydraulic device performing the duty of an actuator, which advances the syringe to inject the medication. The hydraulic fluid is water, oil or a glycerine composition; optionally coloured. Also claimed is a compressed air actuated device, using e.g. a blood pressure manometer.