Syringe Pump

Overview

A syringe pump delivers drugs in small, exact volumes by slowly pushing a syringe plunger at a programmed rate. It is the tool of choice when the dose matters down to the microliter, vasopressors, sedatives, insulin, neonatal infusions, where a free-dripping IV or a coarser volumetric pump would be too imprecise. The clinician loads a standard syringe, enters a rate or a dose, and the pump advances the plunger until the syringe empties or an alarm stops it.

The syringe seats in the Syringe Clamp, which holds the barrel and reports its size. The Plunger Drive pushes the plunger forward through a lead screw, and the Force / Occlusion Sensor watches the force on that plunger to catch a blocked line. A Control Board runs the infusion math and motor control, the User Interface takes rate entry and raises alarms, and a Backup Battery backed by a medical Power Supply keeps it running through transport and power loss. Everything sits in a sealed Housing that clamps to an IV pole.

How it works

Flow rate is set by how fast the plunger moves, and that motion comes from the Plunger Drive. A Drive Stepper Motor turns through reduction gearing into a Ball Screw, converting rotation into the slow linear travel of the plunger head. Because the screw advances a fixed distance per motor micro-step, the pump knows the delivered volume precisely, but only if it also knows the syringe diameter, because a wide 50 mL barrel pushes far more fluid per millimeter than a narrow 5 mL one. The Syringe Size Sensor in the clamp measures that diameter so the controller scales travel into the correct flow.

Safety hinges on the Force / Occlusion Sensor. If the line kinks or a stopcock closes, the plunger meets resistance and the force on the drive climbs; a load cell and Pressure Sensor track that force, and when it crosses the selected occlusion threshold the pump halts and alarms before pressure builds to a dangerous bolus. The Control Board carries two MCUs, one runs the infusion, the second independently cross-checks rate and force so a single fault cannot silently over-deliver. The User Interface presents rate, volume infused, and time remaining, and its alarm speaker calls a nurse on occlusion, near-end-of-syringe, or low battery.