Rotary Pump Occlusion Detection via Cam Rotor Position
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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 for accurate fluid delivery, then manufacturing precision and reliability are improved, but the ability to detect occlusions deteriorates due to lack of integrated sensing capabilities
Solution Approach 1:
The patent combines the pump mechanism and occlusion detection sensing elements into a single integrated rotary micropump assembly. The sensing elements are incorporated within the pump structure itself, allowing the pump to perform both fluid delivery and occlusion detection functions simultaneously, thereby resolving the contradiction between precision delivery and detection capability
Solution Approach 2:
The rotary micropump is designed with multi-functionality, serving both as a precise fluid delivery mechanism and as an occlusion detection system. The sensing elements integrated into the pump structure enable it to detect occlusions while maintaining its primary function of accurate fluid delivery, thus achieving both precision and reliability
2Reliability
If sensor contact elements and sensing elements are added to detect occlusions, then occlusion detection reliability is improved, but device complexity increases
Solution Approach 1:
The sensing elements are merged with the existing pump structure rather than being added as separate external components. The sensor contact elements are integrated into the rotor assembly and the sensing elements into the stator, utilizing the pump's mechanical motion for detection purposes, thereby improving reliability without proportionally increasing complexity
Solution Approach 2:
The pump mechanism's rotational motion serves dual purposes: fluid delivery and occlusion detection. The same mechanical components that enable precise pumping also facilitate occlusion detection through the integrated sensing elements, achieving multi-functionality that improves reliability while minimizing additional complexity
3Measurement precision
If multiple sensing elements are integrated into the pump mechanism, then occlusion detection precision is improved, but manufacturing complexity increases
Solution Approach 1:
Multiple sensing elements are combined into the pump structure in a coordinated arrangement that enables precise occlusion detection. The sensor contact elements on the rotor and sensing elements on the stator are positioned to work together, creating a detection system with high precision while utilizing the existing pump manufacturing processes
Solution Approach 2:
The sensing elements are pre-positioned and pre-configured during pump assembly to ensure optimal detection precision. The rotor and stator are manufactured with integrated sensing features that are aligned during assembly, allowing precise occlusion detection to be achieved through careful preliminary positioning rather than complex post-assembly calibration
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
The sensing element cooperates with a detection circuit to detect whether or not the stator cam surface is in contact with the sensor contact element
Implementation Method 2
A force sensor is coupled to the rotor to generate output levels in response to forces applied to the rotor
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, and the stator includes a cam element having a stator cam surface. The cam elements cooperate to axially displace the rotor as a function of angular position of the rotor. A biasing element provides force to urge the cam elements together. A drive motor actuates the rotor to pump medication fluid from a fluid cartridge module to a body, via a subcutaneous conduit. A detection circuit processes axial and angular position data of the rotor, and determines that an upstream occlusion has occurred based on detectable characteristics of the axial and angular position data.