Infusion Pump Motor Reverse Rotation Prevention

Solution Overview

Problem

Infusion pumps face challenges in preventing reverse rotation during zero flow periods, which can lead to fluid siphoning and mechanical failures, especially under high pressures or pinched tubes, and existing mechanical mechanisms are not effective in detecting and reporting such failures.

Innovation Solution

A system comprising a coil and rotor motor assembly with a rotor position sensor and controller that detects changes in rotor position to prevent reverse rotation by adjusting the coil voltage, ensuring the roller assembly remains stationary during zero flow periods and activating an indicator if reverse rotation occurs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the motor is de-energized during zero flow periods to save energy, then energy efficiency is improved, but reverse rotation of the roller assembly may occur causing fluid siphoning

Engineering Contradiction:

Improveenergy efficiencyVSAvoidprevention of reverse rotation

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent replaces mechanical reverse rotation prevention mechanisms (pawls, clutches) with an electrical control system. The controller monitors rotor position via a sensor and selectively energizes the coil based on infusion schedule and detected reverse rotation, substituting mechanical prevention with electrical control and sensing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses a rotor position sensor to provide feedback about the rotor's position to the controller. The controller uses this feedback to detect reverse rotation and adjust coil energization accordingly, creating a closed-loop control system that prevents reverse rotation while maintaining energy efficiency.

Inventive Principle:

Principle #23Feedback

2Reliability

If mechanical mechanisms like pawls and clutches are used to prevent reverse rotation, then reverse rotation is prevented, but detection and reporting of failure is difficult

Engineering Contradiction:

Improveprevention of reverse rotationVSAvoidfailure detection

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces mechanical reverse rotation prevention mechanisms (pawls, clutches) with an electrical control system. The controller monitors rotor position via a sensor and selectively energizes the coil based on infusion schedule and detected reverse rotation, substituting mechanical prevention with electrical control and sensing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses a rotor position sensor to provide feedback about the rotor's position to the controller. The controller uses this feedback to detect reverse rotation and adjust coil energization accordingly, creating a closed-loop control system that prevents reverse rotation while maintaining energy efficiency.

Inventive Principle:

Principle #23Feedback

3Reliability

If the coil voltage is continuously energized to prevent reverse rotation, then reverse rotation is prevented, but energy consumption increases

Engineering Contradiction:

Improveprevention of reverse rotationVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The controller energizes the coil periodically based on the infusion schedule rather than continuously. During zero flow periods when infusion is not required, the coil remains de-energized to conserve energy, while the controller monitors for reverse rotation and only energizes the coil when needed to prevent reverse rotation or deliver infusion.

Inventive Principle:

Principle #19Periodic action

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

Effectively prevents reverse rotation of the roller assembly during zero flow periods, enhancing safety by avoiding fluid siphoning and enabling early detection of potential failures, while also conserving energy by de-energizing the motor when not in use.

Implementation Method 1

a coil configured to generate a coil field in response to a coil voltage, and a rotor configured to generate a rotor field that cooperates with the coil field to urge the rotor toward a rotor position

Methodology Applied

Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Data Source

PatentUS8858494B2Infusion pump assembly having a reverse rotation prevention system and method for operating the same

Publication Date: 2014.10.14 CURLIN MEDICAL INC

AI summary

A system and method for preventing an undesirable reverse rotation of an infusion pump assembly. The infusion pump motor includes a roller assembly, a coil, a rotor, a rotor position sensor, and a controller. The rotor is in communication with the coil, and the rotor is rotationally coupled to a roller assembly. If the pump is in not pumping, then the system monitors for reverse rotation of the pump, and if reverse rotation of the pump is detected, energizes the coil in a manner that holds the rotor in place. The system may also activate an indicator if reverse rotation is detected.