Syringe Pump Drive System with Resistive Sheet Position Detection
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Solution Overview
Problem
Syringe pumps face issues with inaccurate infusion flow rates due to inadequate monitoring systems and mechanical inaccuracies, leading to potential overdose or underdose in medical treatments, posing safety risks.
Innovation Solution
A drive system for syringe pumps incorporating an outer sleeve with resistive and conductive sheets, an injection pushrod with an elastic conductive contact sheet, and a drive device that enables precise control of infusion by measuring resistance changes between the sheets, ensuring accurate fluid administration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a motor with encoder is used to detect motor operation, then the motor control is improved, but the injection pushrod operation accuracy cannot be ensured due to motion conversion losses in the reducer and drive threads
Solution Approach 1:
The patent replaces the mechanical detection system (encoder on motor) with an electrical detection system (resistive sheet and conductive sheet). The resistive sheet is disposed on the inner wall of the outer sleeve, and the conductive sheet is disposed on the outer periphery of the injection pushrod. When the pushrod moves, the contact position between the sheets changes, providing direct electrical measurement of pushrod position without mechanical transmission components.
Solution Approach 2:
The patent introduces an elastic conductive contact sheet as an intermediary between the resistive sheet and conductive sheet. This elastic sheet ensures continuous contact between the two sheets while allowing for positional changes of the injection pushrod. The elastic property enables the contact sheet to maintain electrical connection while accommodating the movement and sealing requirements of the pushrod.
2Ease of operation
If the injection pushrod moves back and forth to pump medical fluids, then the infusion function is achieved, but the position of the injection pushrod cannot be accurately determined
Solution Approach 1:
The patent replaces mechanical position indication methods with an electrical resistance-based detection system. The resistive sheet and conductive sheet create an electrical circuit where the contact position directly corresponds to the pushrod position. By measuring the electrical resistance or contact point, the system can accurately determine pushrod position without mechanical markers or complex mechanical sensing mechanisms.
Solution Approach 2:
The patent utilizes changes in electrical resistance parameters to indicate position changes. As the injection pushrod moves back and forth, the contact position between the resistive sheet and conductive sheet changes, causing corresponding changes in electrical resistance. This parameter change provides a direct, accurate, and easily measurable indication of pushrod position throughout the infusion cycle.
3Reliability
If the seal between the injection pushrod and outer sleeve is maintained, then fluid leakage is prevented, but the contact between detection sheets may be interrupted
Solution Approach 1:
The patent employs an elastic conductive contact sheet that combines sealing and electrical conduction functions. This thin, flexible sheet maintains continuous contact between the resistive sheet and conductive sheet while accommodating the movement of the injection pushrod. The elastic property allows the sheet to deform and maintain contact pressure, ensuring both fluid sealing and continuous electrical connection throughout the pushrod's motion range.
Solution Approach 2:
The elastic conductive contact sheet serves multiple functions simultaneously: it provides fluid sealing between the pushrod and outer sleeve, maintains continuous electrical contact between the resistive and conductive sheets, and accommodates the positional changes of the pushrod. This multi-functional component resolves the contradiction by integrating sealing and detection contact functions into a single element.
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
The drive system allows for precise control of medical fluid infusion, reducing the risk of adverse events by accurately measuring the position of the injection pushrod and maintaining a consistent infusion rate, thereby enhancing treatment safety and efficacy.
Implementation Method 1
one end of the elastic conductive contact sheet being in contact with the conductive sheet and the other end being in contact with the resistive sheet
Data Source
AI summary
Disclosed is a drive system of a syringe pump, comprising: an outer sleeve (11) having an inner wall provided with a resistive sheet slot and a conductive sheet slot, both of which slot extending axially; a resistive sheet (12) provided in the resistive sheet slot and a conductive sheet (13) provided in the conductive sheet slot; an injection pushrod (14) slidably provided in the outer sleeve (11), wherein a hermetic seal is maintained between the injection pushrod (14) and the inner wall of the outer sleeve (11), and a cavity having an opening is provided on the injection pushrod (14), with the opening of the cavity being provided at a tail end of the injection pushrod (14); an elastic conductive contact sheet (15) fixedly provided on the injection pushrod (14), with one end of the elastic conductive contact sheet (15) being in contact with the conductive sheet (13) and the other end being in contact with the resistive sheet (12); and a drive device provided in the cavity and driving the injection pushrod (14) to move forth and back. The drive system can ensure the accuracy of administration.