Orthopedic Simulator Fluid Concentration Control

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Solution Overview

Problem

Orthopedic device testing, particularly spinal implants, faces challenges in maintaining consistent fluid concentration in specimen baths due to evaporation, leading to non-compliance with ISO standards and potential variability across test stations, which can invalidate testing results.

Innovation Solution

An orthopedic simulator equipped with a fluid level sensor and fill controller that monitors and maintains the fluid concentration by replenishing the bath with a specific fluid, ensuring consistent conditions across all test stations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the specimen bath is sealed to prevent evaporation, then fluid concentration stability is improved, but complete sealing may cause pressure buildup or contamination issues

Engineering Contradiction:

Improvefluid concentration stabilityVSAvoidpressure buildup or contamination

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

A membrane acts as an intermediary between the specimen bath and the external environment. The membrane allows vapor transmission to prevent pressure buildup while blocking liquid contamination, thus resolving the contradiction between maintaining fluid concentration stability and preventing harmful factors.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system maintains an inert or controlled atmosphere within the sealed specimen container to prevent chemical reactions and contamination. This allows the bath to remain sealed for concentration stability while the inert environment prevents harmful chemical interactions.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Measurement precision

If periodic manual checking of fluid concentration is performed, then concentration accuracy is improved, but testing time is increased and contamination risk is elevated

Engineering Contradiction:

Improvefluid concentration accuracyVSAvoidtesting time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

A sensor continuously monitors fluid concentration and provides feedback to the control system. When concentration deviates from the target range, the system automatically adjusts by adding concentrate or diluent, eliminating the need for periodic manual checking and maintaining both accuracy and efficiency.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs self-adjustment of fluid concentration through automated sensing and actuation. The controller automatically adds concentrate or diluent based on sensor feedback, allowing the system to maintain concentration accuracy without human intervention, thus saving time and reducing contamination risk.

Inventive Principle:

Principle #25Self-service

3Stability of the object's composition

If the specimen container is completely sealed, then evaporation is prevented and concentration stability is improved, but vapor pressure may accumulate

Engineering Contradiction:

Improveconcentration stabilityVSAvoidvapor pressure

Core Design Contradiction:

Stability of the object's compositionVSStress or pressure

Solution Approach 1:

A membrane serves as an intermediary that transmits vapor pressure outward while preventing liquid escape and external contamination. This resolves the contradiction by allowing pressure equalization through vapor transmission while maintaining the sealed environment needed for concentration stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system utilizes phase transitions (evaporation and condensation) of the fluid to manage pressure. Vapor generated by evaporation can escape through the membrane or condense on cooler surfaces, preventing pressure accumulation while maintaining the sealed container environment for concentration stability.

Inventive Principle:

Principle #36Phase transitions

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 system effectively maintains the specified fluid concentration in specimen baths, reducing the risk of non-compliance and ensuring consistent testing results across all stations, thereby enhancing the accuracy and reliability of orthopedic device testing.

Implementation Method 1

A fluid level sensor is positioned to sense the level of fluid in the fluid bath and generate a fluid level signal

Methodology Applied

Scientific EffectFluid level sensing:

Implementation Method 2

A controller is provided to control the addition of the replenishing fluid to the specimen bath to maintain the concentration of bovine fluid

Methodology Applied

Scientific EffectFluid mixing:

Data Source

PatentUS7779708B2Orthopedic simulator with fluid concentration maintenance arrangement for controlling fluid concentration of specimen baths

Publication Date: 2010.08.24 MTS SYSTEMS CORPORATION

AI summary

An orthopedic simulator is provided with an orthopedic simulator having at least one test station with a specimen container for containing a fluid bath, such as bovine fluid. A fluid level sensor is positioned to sense the level of fluid in the fluid bath and generate a fluid level signal. A fill controller is coupled to the fluid level sensor. The fill controller controls filling of the fluid bath with liquid, such as distilled water, as a function of the fluid level signal to restore and maintain the concentration of the bath.