Pressure Controlled Fluid Sampler for Rapid Sample Delivery
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Solution Overview
Problem
Conventional autosamplers are limited by the slow aspiration of samples due to negative pressure, which restricts the speed of analysis and introduces cross-contamination and dead-volume issues during pressure switching.
Innovation Solution
A pressure-controlled fluid sampler using positive-pressure liquid displacement to rapidly transfer sample aliquots from reservoirs to detectors, eliminating the need for in-line valving and reducing carry-over and cross-contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If negative pressure or vacuum is used to aspirate the sample into the needle, then the sample can be drawn into the system, but the aspiration speed is limited by the physical limit of 1 atmosphere and cannot be accelerated
Solution Approach 1:
The patent inverts the conventional approach by using positive pressure to push the sample forward instead of negative pressure to pull it. The sample is enclosed in a sealed reservoir and pressurized from behind, reversing the traditional aspiration mechanism and eliminating the 1 atmosphere speed limit.
Solution Approach 2:
The patent applies pneumatic pressure control to manipulate sample flow. A pressure controller regulates gas pressure applied to the sample reservoir, using compressed gas to drive the sample through the capillary tube at controlled rates, replacing the vacuum-based system.
2Object-generated harmful factors
If conventional autosamplers use both positive and negative pressure to deliver samples, then samples can be transported through the system, but valving is required which introduces dead-volume and cross-contamination
Solution Approach 1:
The patent removes the injection valve and sample loop from the flow path. By using positive pressure to directly push the sample plug through the capillary tube to the detector, the system eliminates the valving components that create dead-volume and cross-contamination risks.
Solution Approach 2:
The patent maintains continuous positive pressure throughout the sample transport process, allowing the sample to flow continuously from the reservoir through the capillary tube to the detector without interruption or direction changes that would require valving.
3Speed
If the tubing or needle inner diameter is increased to overcome the negative pressure limit, then faster sample aspiration might be achieved, but this is not practical for low flow rate applications particularly those that use capillary tubes
Solution Approach 1:
Instead of increasing tube diameter to improve flow rate, the patent inverts the approach by maintaining small capillary dimensions and using positive pressure from behind to drive flow. This preserves the advantages of capillary tubes for low flow rates while achieving faster delivery through pressure-driven flow.
Solution Approach 2:
The patent changes the pressure parameter from negative (vacuum) to positive (compressed gas), enabling faster flow rates through capillary tubes without altering the tube dimensions. The pressure controller allows precise regulation of flow rate while maintaining capillary tube compatibility.
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 approach enables faster sample delivery rates and minimizes cross-contamination by using positive pressure to rapidly manipulate samples, overcoming the physical limitations of negative pressure and eliminating the need for fluid switching components in the flow path.
Implementation Method 1
positive-pressure liquid displacement for fluid sampling
Implementation Method 2
capable of communication with a pressurized gas source
Implementation Method 3
a seal capable of forming a compression seal to the at least one sample reservoir when gas pressure is applied
Data Source
AI summary
A fluid sampler system includes a fluidic head including a gas aperture capable of communication with a pressurized gas source, a liquid conduit capable of communication with a sample reservoir, and a seal capable of forming a compression seal to the sample reservoir when gas pressure is applied to the sample reservoir through the gas aperture and capable of displacing a portion of the sample through the liquid conduit; and a positioning apparatus capable of positioning the fluidic head and the sample reservoir in communication with one another. A method for providing an aliquot of sample, includes forming a releasable compression seal to a reservoir including a liquid sample; pressurizing the reservoir with compressed gas; displacing an aliquot of the sample from the reservoir; and transferring the displaced aliquot of the sample to a location.