High precision/low cost sampling pump


Consumable blood analysis device achieves microliter precision while meeting size/cost goals.

The Challenge

Our customer—a large medical equipment manufacturer—required a new design for a precision metering pump for blood analysis sampling. The component was to be used in a disposable cartridge, so relative cost was an issue.

The incumbent peristaltic pump design presented several problems, including: inconsistent/pulsed flow, inertial flow after pump shut off, drawback/reverse flow issues, and variability in flow based on the extruded tubing. The pump required intensive labor during assembly, further driving up the costs of manufacturing the finished cartridge.

The Solution

The Senior team suggested replacing the peristaltic pump with a self-retracting pump, based on a welded metal bellows integrated with a plastic terminal and valves. Solution eliminated virtually every one of the flow-related shortcomings of the peristaltic design, provided a higher cycle life, and offered significant advantages in simplicity, cost, and ease of assembly.

The Results

Elimination of pulsed flow and other flow irregularities, essential microliter precision, encapsulated check valves, high cycle life, simplified manufacturing and assembly, compact package easily fits into a consumable cartridge.