Digital Syringe Plunger Position Sensor
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Solution Overview
Problem
Conventional syringes face challenges in precision and accuracy due to mechanical tolerances, plunger flexibility, and medicament viscosity, making it difficult to deliver precise doses, especially with standard disposable syringes.
Innovation Solution
A digital syringe system with a sensor that directly measures plunger position, eliminating mechanical tolerances and allowing for both manual and automatic operation, using a motor unit and electronic sensors for precise volume control and feedback control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If conventional syringes with mechanical components (motor, gear train, lead screw) are used to drive the plunger, then automated medication delivery is achieved, but mechanical tolerances and stack-up errors reduce measurement precision
Solution Approach 1:
The patent replaces the mechanical measurement system (motor, gear train, lead screw) with an electronic sensor system that directly measures plunger position. The sensor detects the position of the plunger rod or piston directly, eliminating the need to mechanically infer position from motor movements, thereby removing mechanical tolerance stack-up errors from the measurement chain.
Solution Approach 2:
The patent introduces an electronic sensor as an intermediary between the plunger and the measurement system. Instead of mechanically coupling the measurement to the motor components, the sensor acts as a direct intermediary that reads plunger position electronically, decoupling the measurement from mechanical tolerances.
2Ease of manufacture
If standard disposable polymer syringes are used, then cost and sterility are improved, but plunger flexibility and dimensional variations reduce manufacturing precision
Solution Approach 1:
The patent replaces mechanical measurement methods that rely on precise mechanical dimensions with an electronic sensing system. The sensor directly measures the actual plunger position regardless of polymer flexibility or dimensional variations, compensating for manufacturing tolerances in disposable syringes.
Solution Approach 2:
The patent implements a feedback system where the sensor continuously monitors plunger position and provides electronic signals that can be used to correct for variations in plunger movement caused by polymer flexibility or manufacturing tolerances, ensuring accurate medication delivery despite using disposable syringes.
3Measurement precision
If digital syringes with precision metal components are used, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent segments the syringe system into a simple disposable syringe unit and a separate sensor/reader unit. The syringe itself remains a simple polymer construction, while the electronic measurement functionality is provided by an external or attached sensor module, reducing the complexity of the syringe component while maintaining measurement precision.
Solution Approach 2:
The patent creates a universal sensor system that can interface with standard disposable syringes, making the precision measurement capability applicable to conventional syringe designs without requiring specialized metal components in the syringe itself. The sensor unit serves multiple functions including position detection and potentially control feedback.
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
Enables precise and accurate delivery of medicaments with reduced human error, accommodating variations in syringe resistance and medicament viscosity, and allowing for easy tracking of drug delivery.
Implementation Method 1
an electronic sensor attached to and stationary with respect to the housing and sensing a sensor element to provide direct measurement of motion of the plunger along the axis with respect to the housing to provide an electronic signal indicating movement of the plunger
Data Source
AI summary
A digital syringe is used with conventional polymer disposable syringe construction to be practical in the medical environment. Errors associated with the larger volumes of the syringes (which exacerbate minor errors in plunger position) and the flexibility and dimensional variations of the polymer plungers are accommodated by direct measurement of the syringe plunger position rather than indirect measurement of motor position and inference of syringe plunger position. This direct measurement eliminates mechanical tolerances (“stack up”) in the motor, gear train, and lead screw on plunger movement, an effect exacerbated by flexibility of the plunger and changes in syringe resistance and medicament viscosity, for example, with different medicaments or when the syringe is refrigerated. The digital syringe may be combined with the motor unit to provide additional versatility.