Force Sensor Occlusion Detection in Rotary Fluid Infusion Pumps
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Solution Overview
Problem
Current fluid infusion devices with rotary micropump mechanisms lack effective methods for reliably detecting upstream and downstream occlusions, which are critical for ensuring accurate and safe medication delivery.
Innovation Solution
The implementation of a fluid infusion device with a rotary pump mechanism that includes a stator and rotor with cam elements, a sensor contact element, and a sensing element, which cooperate with a detection circuit to monitor angular position and detect occlusions through contact and force sensors, enabling real-time monitoring of fluid flow and occlusion detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a rotary micropump mechanism is used to deliver precise fluid volumes, then manufacturing precision and reliability of fluid delivery are improved, but the ability to detect occlusions (upstream or downstream) deteriorates
Solution Approach 1:
The patent replaces purely mechanical occlusion detection methods with a force sensor that measures mechanical force as an electrical signal. The force sensor detects changes in force exerted by the pump mechanism on the fluid path, converting mechanical information into an electrical signal that can be processed by a microprocessor to identify occlusion conditions.
Solution Approach 2:
The force sensor acts as an intermediary between the mechanical pump operation and the detection system. It measures the force exerted during pump cycles and translates this mechanical information into electrical signals that reveal occlusion conditions, serving as a mediator that enables detection without direct mechanical contact with the fluid path.
2Reliability
If occlusion detection methods are added to the fluid infusion device, then reliability of operation is improved, but device complexity increases
Solution Approach 1:
The force sensor serves multiple functions: it detects occlusions, monitors pump operation, and provides feedback for control. By making the sensor multi-functional, the patent reduces the need for separate dedicated components for each function, thereby limiting the increase in device complexity while improving reliability.
Solution Approach 2:
The force sensor provides continuous feedback signals to the microprocessor about the pump's operation and fluid path conditions. This feedback mechanism enables real-time detection and response to occlusions, improving reliability through active monitoring without requiring complex additional hardware.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for reliable detection of occlusions, preventing medication delivery errors and ensuring safe operation by alerting users and controlling the device's operation, thus maintaining the accuracy and safety of fluid delivery.
Implementation Method 1
A force sensor is coupled to the rotor to generate output levels in response to force imparted thereto
Data Source
AI summary
An embodiment of a fluid infusion device includes a fluid pump mechanism having a rotor and a stator. The rotor includes a reference surface and a cam element rising from the reference surface. The stator includes a cam element having a stator cam surface. The cam elements cooperate to axially displace the rotor as a function of rotation. A biasing element provides force to urge the cam elements together. A drive motor is coupled to actuate the rotor to pump medication fluid from a fluid cartridge module to a body, via a subcutaneous conduit. A force sensor is coupled to the rotor to generate output levels in response to force imparted thereto. The force sensor cooperates with a detection circuit that obtains and processes the output levels to detect occlusions in a fluid path downstream of the fluid pump mechanism.