Thin Film Induction Nebulizer for High TDS Samples
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Solution Overview
Problem
Current nebulizer designs, particularly concentric nebulizers, are prone to plugging and inconsistency when handling samples with high total dissolved solids (TDS) and particulates, limiting their utility at low sample uptake rates required for modern ICP-MS instruments.
Innovation Solution
A thin film induction nebulizer design with a large inner diameter liquid capillary and a partially enclosed chamber that enhances induction and suction, allowing for consistent sample delivery and increased atomization efficiency, even at low sample uptake rates, using a gas capillary with a non-tapered body and tapered end to generate high gas pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a concentric nebulizer with a small inner diameter liquid capillary is used, then a fine mist is generated suitable for spectroscopic instruments, but the liquid capillary becomes prone to plugging by particulates and high TDS samples
Solution Approach 1:
The nebulizer is divided into separate functional zones: a large inner diameter liquid capillary for sample introduction, a separate induction region, and a mist generation region. This segmentation allows the liquid capillary to maintain a large diameter for plugging resistance while the mist generation region produces fine droplets through the interaction of gas flow with the liquid stream.
Solution Approach 2:
A gas stream acts as an intermediary between the liquid sample and the detection system. The gas flow induces and carries the liquid through the nebulizer, enabling the liquid capillary to have a larger diameter while still achieving fine mist generation through the gas-liquid interaction in the induction region.
2Reliability
If a large inner diameter liquid capillary is used, then plugging resistance is improved, but mist fineness and analytical sensitivity are reduced
Solution Approach 1:
Different regions of the nebulizer have different functional requirements. The liquid capillary region is designed with large inner diameter for plugging resistance, while the mist generation region is designed to produce fine droplets. Each region has optimized local characteristics that would be contradictory if applied uniformly throughout the entire device.
Solution Approach 2:
The solution moves from a single-dimension approach (capillary diameter) to a multi-dimensional approach by introducing gas flow dynamics, induction region geometry, and spatial separation of functions. This allows independent optimization of plugging resistance and mist fineness through different spatial and operational parameters.
3Productivity
If induction is increased to draw liquid into the gas stream, then sample introduction efficiency is improved, but liquid flow consistency deteriorates
Solution Approach 1:
The liquid sample is pre-formed into a consistent stream or film before entering the high-induction region. This preliminary structuring of the liquid ensures that even when subjected to strong induction forces, the liquid maintains flow consistency and does not become erratic or discontinuous.
Solution Approach 2:
The nebulizer design creates a reproducible flow pattern through geometric features that guide the liquid in a predictable manner. By establishing a consistent liquid path and interaction zone with the gas stream, the system produces repeatable performance across different operating conditions.
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 nebulizer effectively handles high solid content and particulate-containing samples with improved analytical precision and sensitivity comparable to or exceeding that of concentric nebulizers, while minimizing plugging and maintenance requirements, ensuring reliable performance at low sample uptake rates.
Implementation Method 1
Gas at a higher pressure exits from a small orifice into gas at a lower pressure and forms a gas stream in the lower pressure zone. This pushes the lower pressure gas away from the orifice and generates gas flow in the lower pressure gas zone. This in turn draws some of the lower pressure gas into the higher pressure gas stream. The draw of the lower pressure gas creates lower pressure at the orifice. This creates considerable suction at the orifice
Implementation Method 2
Pneumatic induction nebulizers generally operate in the following manner, relying on the Venturi effect to draw liquid into a gas stream
Implementation Method 3
The roughened surface of the liquid channel allows wetting of the liquid channel with liquid that exits from the liquid opening
Data Source
AI summary
A thin film induction nebulizer is disclosed herein. The nebulizer has a gas capillary and a liquid capillary that are aligned in the same direction within a nebulizer housing and are substantially aligned with a main axis of the nebulizer housing. The nebulizer includes a liquid opening configured to allow liquid to exit the liquid capillary and a gas orifice configured to allow gas to exit the gas capillary. The liquid capillary opens into a chamber that is formed from a liquid channel having a roughened surface and a cover plate. The cover plate interfaces with the liquid channel to partially seal the chamber. The chamber includes an opening where the liquid opening opens into the chamber and also includes another opening proximal to the gas orifice. The end of the nebulizer housing that is proximal to the liquid opening and the gas orifice includes two angled exterior surfaces.