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Integrated Multiline Bubble & Occlusion Sensor for Compounding System

Market: Medical, Pharmaceutical | Product Line: Bubble & Load Cells


Drug and nutrient compounding pumps are able to automatically mix several compounds together to create a solution that contains appropriate doses of multiple drugs and nutrients. During this process, it is critical that minimal air bubbles are introduced to the mixture. Air in the line can affect the amount of drugs or nutrients dispensed into the mixture, possibly causing incorrect dosages.

In addition, a blockage in any of the lines could result in either inappropriate amounts of drugs or nutrients being introduced to the mixture, or the mixture not reaching its intended destination in the first place. Upstream occlusion sensors detect blockages noninvasively by monitoring the force exerted by the tubing during a dispense.

Customer Challenge:

Detection of air bubbles and line blockages is critical in ensuring the proper function of a drug and nutrient compounding pump. The sensor must be able to detect bubbles of various sizes and blockages across multiple lines of various diameters.

Strain Measurement Devices Solution:

In order to address both air bubble and occlusion issues unique to drug and nutrient compounding pumps, Strain Measurement Devices has built an integrated occlusion and bubble sensor that can accommodate multiple lines at once. A total of four bubble sensors, utilizing SMD’s proprietary ultrasonic detection hardware and software, monitor multiple lines for bubbles. These sensors are calibrated using customer supplied tubing to detect dangerous bubble sizes and ignore “nuisance” bubbles.

Two occlusion sensors monitor multiple lines. Each occlusion sensor is designed and calibrated such that it can detect an increase or decrease in pressure indicative of a blockage event. The sensor does this by non-invasively measuring in line pressure. An increase in pressure indicates a downstream occlusion, while a decrease in pressure indicates an upstream occlusion. The sensor includes an integrated lid with a magnetic latch and a reed switch to detect when the lid is closed.