Peristaltic Pump Roller Parking for Pressure Isolation

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Solution Overview

Problem

Prior art peristaltic pumps using rotating roller heads face issues with unwanted pressure pulsations and potential failure under transient high positive pressures, particularly in ophthalmic surgical procedures, due to the exposure of elastomeric flow channels to high pressures, which can lead to cassette failure.

Innovation Solution

A peristaltic pump design with radially mounted rollers that compress elastomeric flow channels against a rigid substrate, and a mechanism to park the rollers during high positive pressure events, isolating the fluid channel from transient pressures by pinching the channel near the input end.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the elastomeric flow channels are exposed to transient high positive pressures during reflux operations, then the peristaltic pump can maintain fluid flow, but the cassette may fail due to pressure-induced damage

Engineering Contradiction:

Improveability to handle reflux operationsVSAvoidcassette durability under pressure

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent extracts the elastomeric flow channels from direct exposure to high positive pressures by introducing a rigid substrate that shields them. The rollers compress the elastomeric channels against the rigid substrate, which blocks the transmission of transient high pressures to the elastomer, thereby preventing cassette failure while maintaining pump functionality during reflux operations

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The rigid substrate acts as an intermediary element between the elastomeric flow channels and the high positive pressure environment. It mediates the pressure transmission by blocking direct pressure transmission to the elastomer while still allowing the rollers to compress the channels effectively for fluid pumping

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the pump head rollers continuously compress the elastomeric flow channels, then fluid flow is maintained, but pressure pulsations are generated that can cause cassette failure

Engineering Contradiction:

Improvecontinuous fluid pumpingVSAvoidpressure pulsations

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful pressure pulsations generated by continuous roller compression into a beneficial protective mechanism. The rigid substrate, which is compressed along with the elastomeric channels, serves as a pressure barrier that transforms the pulsating forces into a stabilizing structure, preventing the pulsations from damaging the cassette while maintaining continuous fluid flow

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If a friction fit construction technique is used to attach the elastomeric sheet to the rigid substrate, then assembly is simplified, but the interface fails under transient high positive pressures

Engineering Contradiction:

Improveassembly simplicityVSAvoidinterface stability under pressure

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the attachment parameter from friction-based mechanical connection to chemical bonding. By using adhesives to bond the elastomeric sheet to the rigid substrate, the interface strength is significantly increased to withstand transient high positive pressures during reflux operations, while the bonding process remains integrated into the manufacturing workflow

Inventive Principle:

Principle #35Parameter changes

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

This design minimizes elastomeric sheet exposure to high pressures, reducing the risk of cassette failure and maintaining fluidic integrity during reflux operations, while simplifying the loading process and reducing pressure pulsations.

Implementation Method 1

Most prior art peristaltic pumps work by compressing or squeezing a length of flexible tubing (sometimes between a fixed race) using a rotating roller head. As the roller head rotates, the rollers pinch off a portion of the tubing and push any fluid trapped in the tubing between the rollers in the direction of rotation.

Methodology Applied

Scientific EffectPeristalsis: Peristalsis

Implementation Method 2

a molded flow channel contained on an elastomeric sheet that is bonded or mechanically attached to a rigid substrate

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS8079836B2Method of operating a peristaltic pump

Publication Date: 2011.12.20 ALCON INC

AI summary

A method for operating a peristaltic pump having a molded flow channel contained on an elastomeric sheet that is bonded or mechanically attached to a rigid substrate. The pump head rollers are mounted radially from the axis of rotation of the pump motor and compress the elastomeric flow channels against the rigid substrate. During reflux, the pump head is positioned so that at least one of the rollers compresses the elastomeric flow channel at the input end of the peristaltic pump. Such an operation minimizes the amount of the elastomeric sheet that is exposed to high transient pressures.