Dual-Latching Microvalve Metastable Priming for Safe Drug Flow
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Solution Overview
Problem
Existing dual latching microvalves do not allow for a metastable state where both fluid paths can be open simultaneously, making it difficult to prime the fluidic system, which is crucial for applications like on-body drug delivery where safe filling and metering are essential.
Innovation Solution
The introduction of a metastable state in dual latching microvalves, where both inlet and outlet valves are open at the same time, utilizing an interference mechanism such as a cam with specific shaping and resilience features, or alternative mechanisms like a removeable pin, to enable easy priming and filling of the fluidic system before transitioning to a stable operational state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dual latching microvalves are designed to prevent both valves from being open simultaneously (stable state), then safety is improved by preventing accidental overdose, but the ability to prime the fluidic system is worsened
Solution Approach 1:
The valve system transitions from a static stable state to a dynamic metastable state during priming operations. The cam mechanism allows temporary dynamic positioning where both valves can be open, enabling priming, then returns to the stable latched state for safe operation. This dynamic state transition resolves the contradiction between safety and priming capability.
Solution Approach 2:
The system performs preliminary priming action in a metastable state before transitioning to the stable operational state. The cam mechanism enables temporary simultaneous opening of both valves to fill the fluidic system with fluid, then latches into the stable state where only one valve remains open, ensuring safety before actual drug delivery begins.
2Ease of operation
If dual latching microvalves are designed to allow simultaneous opening of both valves for priming (metastable state), then priming capability is improved, but safety is worsened by risk of accidental overdose
Solution Approach 1:
The valve system transitions from a static stable state to a dynamic metastable state during priming operations. The cam mechanism allows temporary dynamic positioning where both valves can be open, enabling priming, then returns to the stable latched state for safe operation. This dynamic state transition resolves the contradiction between safety and priming capability.
Solution Approach 2:
The system performs preliminary priming action in a metastable state before transitioning to the stable operational state. The cam mechanism enables temporary simultaneous opening of both valves to fill the fluidic system with fluid, then latches into the stable state where only one valve remains open, ensuring safety before actual drug delivery begins.
3Extent of automation
If a cam mechanism is used to control valve timing, then coordination between valves is improved, but device complexity is worsened
Solution Approach 1:
The cam mechanism combines multiple valve control functions into a single integrated component. The cam profile simultaneously controls the timing of both inlet and outlet valves, coordinating their opening and closing sequences through a unified mechanical element driven by the electrochemiosmotic pump, thereby reducing overall system complexity despite the sophisticated coordination achieved.
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 allows for safe and efficient priming of the fluidic system, preventing accidental overdose in drug delivery applications by ensuring both valves can be open during filling, and then safely transitioning to a stable state where only one valve is open at a time, ensuring controlled fluid flow.
Implementation Method 1
The wire rotates the cam which pinches a resilient compressible tube stopping flow, or releases the tube permitting flow. This can be achieved with the cam directly or using a cam follower, such as a valve end, that compresses and releases the resilient tubing.
Implementation Method 2
The valve mechanism is actuated by passing a current through a shape memory alloy (SMA) wire, causing the wire to heat and contract.
Data Source
AI summary
A dual latching microvalve is capable of a metastable state, wherein a one or more complete flow paths are open, before switching to another state that allows only an inlet or outlet valve to be open at any time on any fluid path. One valve mechanism uses a cam to alternately open and close two valves, with an external force applying pressure to move one valve arm onto a resting position on the cam, thereby opening the closed valve and provided an uninterrupted flow path through the dual latching microvalve. The metastable state provides, for example, a means to prime the pump before operation, such as pumping of insulin into a patient. When released from the metastable state, the dual latching microvalve operates in a fashion whereby opening of both valves simultaneously is prevented, thereby protecting the patient from injury.