Rectangular Nozzle Feed Tube for High-Speed Particle Alignment
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Solution Overview
Problem
Existing nozzles for flow cytometers are ineffective in aligning non-rotationally symmetrical particles, such as mammalian sperm, due to asymmetrical pressure and flow conditions, leading to less uniform alignment at higher speeds and good alignment only at low speeds.
Innovation Solution
A nozzle design with a feed tube having a rectangular or elliptical internal cross-section that tapers towards the outlet, allowing particles to maintain constant orientation and be aligned through a mechanical process without lateral pressure gradients, using a laminar flow with a velocity gradient to align particles within the core stream before they exit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional nozzles with asymmetrical inner cross-sections are used to align particles, then particle alignment is achieved through hydrodynamic pressure gradients, but alignment uniformity deteriorates at higher flow speeds
Solution Approach 1:
The feed tube employs an asymmetrical rectangular cross-section with width-to-height ratio between 2:1 and 10:1, creating a mechanically induced velocity gradient that aligns non-rotationally symmetrical particles. This asymmetrical geometry generates differential drag forces on particles, orienting them along the flow direction without relying on hydrodynamic pressure gradients, thereby maintaining alignment uniformity at high flow speeds
Solution Approach 2:
The invention replaces the hydrodynamic pressure gradient mechanism with a mechanically induced velocity gradient system. The rectangular feed tube geometry creates a velocity distribution where fluid moves faster near the wider walls and slower near the narrower walls, generating a velocity gradient that mechanically orients particles through differential drag forces, eliminating the speed-dependent limitations of pressure gradient-based alignment
2Productivity
If nozzle flow rate is increased to improve sorting productivity, then sorting rate increases, but particle alignment uniformity deteriorates
Solution Approach 1:
The asymmetrical rectangular feed tube cross-section creates a velocity gradient that scales with flow rate. As flow rate increases to improve productivity, the velocity gradient increases proportionally, maintaining effective particle alignment forces across a wide range of operating speeds, thus decoupling productivity from alignment quality
Solution Approach 2:
The invention changes the geometric parameters of the feed tube (rectangular cross-section with specific width-to-height ratio) to create a velocity gradient mechanism that is inherently scalable with flow rate. This parameter optimization allows the system to maintain alignment effectiveness across varying productivity requirements, enabling high-speed sorting without sacrificing alignment uniformity
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 enables high-speed alignment and separation of particles into fractions with uniform orientation, improving sorting rates and efficiency by maintaining particle alignment without the limitations of conventional nozzles.
Implementation Method 1
using a laminar flow with a velocity gradient to align particles within the core stream before they exit
Implementation Method 2
The alignment of the particles is achieved by the elongated inner cross-section of the feed tube... the higher velocity of the surrounding flow fluid relative to the core flow fluid, achieved when using the nozzle, results in a spacing of the particles from one another. Hydrodynamic alignment, achieved by a lateral pressure gradient on the core flow fluid generated by an elliptical nozzle, only contributes to this alignment
Data Source
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AI summary
The invention describes a nozzle and a method for aligning asymmetric particles through the nozzle, in which a feed tube for core flow fluid runs and has a cross-section perpendicular to its longitudinal axis, which is spanned by a first and a second dimension, wherein the cross-section in the first dimension is smaller than in the second dimension, so that the feed tube has an elongated, non-rotationally symmetrical inner cross-section at least in a section adjacent to its opening.