Fluid Drug Cartridge Identification via Plunger Force Modulation
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Solution Overview
Problem
Current fluid drug injection systems face challenges in accurately identifying different types of cartridges, which vary in insulin concentration, leading to uncertainties in the correct volume of insulin to be injected, and existing occlusion detection methods are not reliable across a broad range of delivery rates.
Innovation Solution
The system encodes data into the force necessary to move a plunger within a fluid drug cartridge as a function of time, using feature signals that include modulations in force, amplitude, and duration, which are compared to a database to identify the cartridge type, and incorporates a force sensor to measure and analyze these signals during priming or operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If force sensor measurement is used to identify cartridge type, then identification accuracy is improved, but device complexity increases due to additional hardware
Solution Approach 1:
The cartridge itself generates the identification signal through its own mechanical features (extensions, texturing, geometry) that interact with the plunger actuator during normal operation. The force variations produced are intrinsic to the cartridge design, eliminating the need for external identification hardware or separate identification mechanisms.
Solution Approach 2:
The patent replaces electronic identification methods (such as RFID chips or barcodes) with a mechanical identification system. The cartridge type is identified through mechanical interactions between the plunger actuator and cartridge features, with force sensor measurements converting mechanical variations into identification data.
2Reliability
If existing occlusion detection methods are used, then occlusion detection is achieved, but reliability across broad delivery rates deteriorates
Solution Approach 1:
The system dynamically adapts its detection parameters based on the measured delivery rate. By continuously monitoring force variations during plunger actuation and comparing them against rate-specific profiles, the system maintains reliable occlusion detection across varying delivery rates rather than using fixed detection thresholds.
Solution Approach 2:
The patent changes the detection parameters (force thresholds, measurement rates, analysis windows) based on the operating conditions and delivery rate. This allows the occlusion detection system to remain sensitive and accurate whether the pump is operating at high or low delivery rates.
3Reliability
If multiple occlusion detectors operating at different measurement rates are used, then occlusion detection coverage is improved, but device complexity increases
Solution Approach 1:
The single force sensor serves multiple functions: it measures occlusion forces, identifies cartridge type, and provides delivery rate information. By making the force measurement system multi-functional, the patent achieves comprehensive monitoring without requiring separate detection systems for each function.
Solution Approach 2:
The patent combines cartridge identification and occlusion detection functions into a single integrated system using the same force sensor and control unit. The force measurement data is analyzed simultaneously for both identification purposes and safety monitoring, reducing the number of required components.
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 method allows for accurate identification of fluid drug cartridges without additional hardware, ensuring appropriate operation based on the type of fluid drug solution and reducing the risk of misidentification, thereby enhancing the reliability of insulin delivery.
Implementation Method 1
monitoring the force necessary to move a plunger within a barrel of the fluid drug cartridge as a function of time
Data Source
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AI summary
The invention provides for a method of determining a cartridge type (320) with a fluid drug injection system (300). The fluid drug injection system comprises a pump (301) configured for receiving a fluid drug cartridge (100). The fluid drug cartridge comprises a barrel (102) filled with a fluid drug solution (104). The fluid drug cartridge comprises a plunger (106) within the barrel. The plunger is configured for forcing the fluid drug solution through an outlet (110) of the barrel. The pump comprises an actuator (122) for actuating the plunger to force the fluid drug solution through the outlet. The fluid drug injection system comprises a force sensor (128) for measuring force data (314). The force data is descriptive of the force applied to the plunger by the actuator. The method comprises: moving (400) the actuator to contact the plunger or move the plunger; measuring (402) the force data using the force sensor; determining (404) a feature signal (316, 700, 1102, 1300, 1500, 1700, 900) from the force data, wherein the feature signal is descriptive of a force modulation, wherein the feature signal is a characterization of any one of the following: a force modulation amplitude, a force modulation duration, a force modulation number; and assigning (406) the cartridge type to the fluid drug cartridge using the feature signal.