Syringe Pump Magnetoresistive Sensor Lead Screw Position Control
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Solution Overview
Problem
Existing syringe pumps have low precision and poor reliability in controlling infusion speed, particularly in applications like intravenous injections for newborns and insulin delivery, and are costly due to the use of step motors and other high-cost sensors.
Innovation Solution
A syringe pump design incorporating a magnetoresistive sensor and a Micro Control Unit (MCU) to control the direction and velocity of a lead screw driven by a motor, using permanent magnets to enhance precision and reliability, and allowing the use of a cost-effective DC motor instead of a step motor, with features like a magnetoresistive sensor information management unit for precise infusion speed control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a step motor is used to control the lead screw, then the infusion speed precision is improved, but the manufacturing cost increases
Solution Approach 1:
The patent replaces the step motor (electromechanical system) with a permanent magnet on the lead screw combined with a magnetoresistive sensor (magnetic field sensing system). This substitution eliminates the need for complex motor control while achieving precise position detection through magnetic field changes, thereby reducing manufacturing cost while maintaining infusion speed precision.
Solution Approach 2:
The patent uses a magnetoresistive sensor to detect the position of the permanent magnet on the lead screw, creating a non-contact copying of position information. This allows precise measurement of lead screw displacement and infusion speed without mechanical contact or complex encoding, simplifying the system and reducing cost while maintaining precision.
2Reliability
If a magnetoresistive sensor is used to detect lead screw position, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent replaces complex mechanical position detection systems with a magnetoresistive sensor that detects magnetic field changes. This non-contact sensing method improves reliability by eliminating mechanical wear and contact issues, while the sensor's compact design and simple magnetic field detection principle keep the added complexity minimal.
Solution Approach 2:
The patent changes the detection parameter from mechanical position (requiring complex encoders or scales) to magnetic field strength and direction. The magnetoresistive sensor detects changes in magnetic field parameters as the permanent magnet rotates with the lead screw, providing reliable position information through simple magnetic field parameter changes rather than complex mechanical structures.
3Measurement precision
If permanent magnets are added to the lead screw, then the precision of plunger position monitoring is improved, but the manufacturing cost increases
Solution Approach 1:
The patent uses the permanent magnet on the lead screw to create a magnetic field signature that copies the position information. The magnetoresistive sensor detects this magnetic signature to determine plunger position with high precision. The permanent magnet itself is simple and inexpensive, making this copying approach cost-effective compared to electronic encoders or other precision sensing systems.
Solution Approach 2:
The patent utilizes the magnetic field parameters (strength and direction) generated by the permanent magnet to encode position information. As the lead screw rotates and the permanent magnet moves, the magnetic field parameters change in a predictable pattern that the magnetoresistive sensor can detect, providing precise position monitoring through simple parameter changes rather than complex mechanical markings or electronic 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
The solution provides high sensitivity, reliability, low power consumption, and reduced costs, improving the precision and usability of syringe pumps by accurately monitoring plunger position and infusion speed, reducing the need for expensive step motors and lowering power consumption.
Implementation Method 1
a magnetoresistive sensor that can sense a magnetic field generated by the at least one permanent magnet
Implementation Method 2
at least one permanent magnet, the at least one permanent magnet being located on the lead screw and rotating therewith
Implementation Method 3
a motor, a lead screw and a syringe driving head connected to the lead screw, and the motor driving the lead screw to rotate
Data Source
AI summary
A precision syringe pump employing a syringe comprises a motor, a lead screw and a syringe driving head connected to the lead screw. The syringe comprises a cylinder and a plunger. The motor drives the lead screw to rotate clockwise or counterclockwise to drive the syringe driving head and push the plunger to move within the cylinder. The syringe pump further comprises: a magnetoresistive sensor, at least one permanent magnet and an MCU, the at least one permanent magnet being located on the lead screw and rotating therewith; the magnetoresistive sensor can sense the magnetic field generated by the at least one permanent magnet; the input end of the MCU is connected to the magnetoresistive sensor, and the output end of the MCU is connected to the motor; the MCU receives signals from the magnetoresistive sensor and controls, according to the signal feedback, the direction and velocity of the lead screw rotated by the motor. The precision syringe pump of the present invention is characterized by high sensitivity, high reliability, low power consumption and low cost, and is convenient to use.