SMA Membrane Valve Actuation for Low-Dead-Volume Flow Cells

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Solution Overview

Problem

Existing fluidic systems with reagent cartridges and flow cells face challenges in precise and efficient actuation of membrane valves, leading to inefficiencies in fluid dispensing and increased dead volume, which affects the accuracy and speed of fluidic operations.

Innovation Solution

The implementation of shape memory alloy (SMA) actuators and valve drive assemblies that utilize SMA wires to actuate membrane valves, allowing for precise control of fluid flow between reagent fluidic lines and a common fluidic line, reducing dead volume and cycle times by spacing valves closely together.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If conventional actuators are used to actuate membrane valves, then the valves can be operated, but the system occupies more space and has increased dead volume

Engineering Contradiction:

Improvedead volumeVSAvoidvalve actuation precision

Core Design Contradiction:

Volume of moving objectVSEase of operation

Solution Approach 1:

The patent replaces conventional mechanical actuators with shape memory alloy (SMA) actuators that use thermal-mechanical coupling to actuate membrane valves. The SMA wires convert electrical energy to thermal energy, which then produces mechanical displacement, eliminating the need for bulky mechanical actuation mechanisms and reducing dead volume in the fluidic path.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the actuation parameter from direct mechanical force to thermal-induced dimensional change. By applying electrical current to SMA wires, the temperature and length of the wires change, which directly actuates the membrane valves. This parameter change enables more compact actuator design with reduced dead volume.

Inventive Principle:

Principle #35Parameter changes

2Area of stationary object

If valves are spaced closely together to reduce footprint, then the system size is reduced, but precise actuation control becomes more difficult

Engineering Contradiction:

Improvesystem footprintVSAvoidfluid dispensing accuracy

Core Design Contradiction:

Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent segments the actuation system into individual SMA wire actuators for each membrane valve, with each actuator independently controlled. This segmentation allows valves to be spaced closely together while maintaining precise independent control of each valve, as each SMA actuator can be individually addressed and controlled without interfering with adjacent valves.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces independent electrical control circuits as intermediaries between the control system and each membrane valve. These intermediary control circuits enable precise individual actuation of each closely-spaced valve through its dedicated SMA wire, maintaining measurement precision despite reduced spacing between valves.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If conventional actuation systems are used, then the system can operate, but the cycle times are increased due to larger component sizes

Engineering Contradiction:

Improveoperational cycle timeVSAvoidreagent consumption

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The patent replaces conventional mechanical actuators with SMA actuators that have faster response times. The direct thermal-mechanical conversion in SMA wires eliminates mechanical inertia and friction delays, reducing actuation cycle times and enabling faster fluid dispensing operations, which improves productivity and reduces reagent consumption per unit time.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution enables accurate and rapid dispensing of small fluid volumes with a reduced footprint, minimizing reagent consumption and shortening operational cycles by using SMA actuators to control membrane valves, thereby improving the efficiency and precision of fluidic operations in fluidic systems.

Implementation Method 1

Applying a voltage to the shape memory alloy wire retracts the shape memory alloy wire

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

shape memory alloy actuators are positioned between the printed circuit board and the end plate. Each shape memory alloy actuator includes a pair of wire mounts coupled to opposing sides of the printed circuit board, an actuator rod is positioned between the lateral sides of the housing and includes a wire guide and a shape memory alloy wire coupled to the wire mounts and positioned around the wire guides

Methodology Applied

Scientific EffectShape memory alloy effect: Shape Memory Alloy

Data Source

PatentUS11555486B2Actuation systems and methods

Publication Date: 2023.01.17 ILLUMINA INC

AI summary

Actuation systems and methods are disclosed. An apparatus includes a system including a flow cell receptacle and a valve drive assembly including a shape memory alloy actuator including a pair of shape memory alloy wires and a flow cell disposable within the flow cell receptacle and having a membrane valve. The system actuates the membrane valve, via the shape memory alloy actuator, by causing a voltage to be applied to a first one of the shape memory alloy wires and the system not applying the voltage to a second one of the shape memory alloy wires.