Small-Volume Liquid Sampler With Grooved Valve Flow Diversion
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Solution Overview
Problem
Existing liquid sampling devices struggle to accurately and hygienically capture small initial volumes of a liquid flow, such as first-void urine, due to challenges in miniaturization, material limitations, and issues with fluid redirection and contamination prevention.
Innovation Solution
A device with a valve structure and casing that includes a gate with elongated grooves and a lifting member, allowing precise sampling of initial volumes through a sample outlet while preventing contamination, and components made from biodegradable materials for user convenience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the device is miniaturized to sample smaller volumes, then the sampling precision for small initial volumes is improved, but the buoyancy force for lifting the valve is strongly reduced
Solution Approach 1:
The patent changes the lifting mechanism from buoyancy-based to pressure-based. A pressure-sensitive membrane responds to pressure differential changes caused by liquid flow, opening the valve when pressure exceeds a threshold. This parameter change from buoyancy to pressure enables reliable valve operation in miniaturized devices where buoyancy forces are too weak.
Solution Approach 2:
The patent replaces the mechanical buoyancy-based lifting system with a pressure-responsive membrane system. The pressure-sensitive membrane acts as a actuator that opens the valve in response to pressure differential, eliminating the need for buoyant forces to lift the valve structure.
2Device complexity
If the wall thickness is reduced below 0.5 mm to minimize material usage, then the device complexity is reduced, but filling issues occur during injection molding
Solution Approach 1:
The patent specifies a wall thickness range of 0.3-0.5 mm as the optimal balance point. This parameter optimization ensures sufficient structural integrity and moldability while minimizing material usage. The groove structures are designed with appropriate depth and spacing to accommodate this thin wall thickness without causing filling issues during injection molding.
Solution Approach 2:
The patent incorporates groove structures that segment the wall thickness distribution. These grooves create localized variations in wall thickness, allowing the majority of the device to have thin walls (0.3-0.5 mm) while providing necessary structural support at critical locations. This segmentation approach maintains manufacturability while minimizing overall material usage.
3Volume of moving object
If tubular ducts of small diameter are used to redirect sampled liquid, then the device volume is reduced, but liquid accumulation occurs in the chamber due to capillary action
Solution Approach 1:
The patent extracts the liquid redirection function from narrow tubular ducts and implements it through a valve-controlled passageway system. The valve structure actively controls liquid flow direction, preventing accumulation in chambers. Liquid is directed through controlled pathways rather than passive capillary-driven flow in narrow tubes.
Solution Approach 2:
The patent replaces passive capillary-driven liquid redirection with an active pressure-driven system. The pressure-sensitive membrane and valve structure create controlled pressure differentials to direct liquid flow, eliminating reliance on capillary action in narrow ducts that causes accumulation.
4Reliability
If the valve structure is designed to quickly drain the initial volume, then the reliability of sampling is improved, but the device complexity increases
Solution Approach 1:
The patent implements a self-regulating valve system where the pressure-sensitive membrane automatically responds to pressure differentials. The valve opens when inlet pressure exceeds the membrane's threshold and closes when pressure equalizes. This self-service mechanism provides reliable sampling control without requiring external actuation or complex control systems.
Solution Approach 2:
The patent uses a pressure-sensitive membrane with a specific threshold response characteristic. This parameter-based control mechanism provides reliable valve operation through simple pressure differential sensing. The membrane's threshold response ensures the valve opens at the appropriate moment during liquid flow and closes automatically, providing reliable sampling with minimal structural complexity.
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 device effectively samples small initial volumes with minimal contamination, accommodating various flow rates and user comfort, while being easily assembled and disposed of, enhancing the reliability of diagnostic tests.
Implementation Method 1
a lifting member connected to the stem for moving the valve structure from the sampling position to the diverting position while the initial volume of the liquid flow is being sampled through the sample outlet
Data Source
AI summary
A device for sampling an initial volume of a liquid flow is disclosed which comprises an inlet conduit, an outlet conduit, and valve casing. The valve casing has a passageway formed therethrough. A sample outlet extends through the valve casing and into the passageway. A valve structure is arranged for axial movement in the valve casing. A gate of the valve structure obstructs the passageway and prevents an initial volume of the liquid flow from being transferred to the outlet conduit when the valve structure is moved to a sampling position. A stem of the valve structure obstructs the sample outlet without obstructing the passageway when the valve structure is moved to a diverting position. At least one elongated groove is formed in a surface of the gate and extends into the stem such that the initial volume is directed through the sample outlet and towards a receptacle when the valve structure is moved to the sampling position. A lifting member moves the valve structure from the sampling position to the diverting position.