Electrospray Ion Source Assembly Thermal Insulation
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Solution Overview
Problem
Existing electrospray ion sources face challenges in preventing excessive heat transfer to the capillary, which can lead to degradation of samples or boiling of solvents, particularly due to the inadvertent heating from concentric nebulizer and desolvation gases, and current solutions result in bulky designs or significant instrumental effort for active cooling.
Innovation Solution
A compact assembly is designed with a capillary encased by a first tube creating a conduit for a heatable gas, and a hollow member with an evacuated space around the capillary to impede heat transfer, using materials with high thermal resistance and low conductivity, optionally with a stagnant gas layer and a heat conductor to manage heat effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heated gas is used to promote evaporation of droplets in the ionization chamber, then evaporation efficiency is improved, but heat transfer to the capillary causes sample degradation or solvent boiling
Solution Approach 1:
A hollow member with an internal evacuated space is positioned around the capillary to act as a thermal barrier. The vacuum environment within the hollow member provides thermal insulation, preventing heat from the heated gas in the first conduit from transferring to the liquid in the capillary, thus protecting the sample while allowing efficient droplet evaporation in the ionization chamber
Solution Approach 2:
The evacuated space within the hollow member creates a vacuum environment that serves as a thermal insulator. This vacuum barrier effectively blocks heat transfer from the external heated gas to the capillary, maintaining the integrity of the liquid sample while permitting controlled evaporation processes to occur
2Object-affected harmful factors
If a solid insulating sleeve or jacket is disposed about the capillary to prevent heat transfer, then heat protection is improved, but the design becomes bulky and increases spatial requirements
Solution Approach 1:
The hollow member with evacuated space serves as a compact thermal barrier around the capillary. The vacuum environment provides effective thermal insulation without requiring thick solid insulation layers, thus protecting the capillary from heat while maintaining a compact overall design that does not significantly increase spatial requirements
Solution Approach 2:
The hollow member acts as a thin-walled protective shell around the capillary. This shell structure provides thermal protection through its evacuated interior space while maintaining a compact form factor, avoiding the bulkiness associated with traditional solid insulating jackets
3Object-affected harmful factors
If active cooling mechanism with water circulation is implemented, then heat transfer prevention is improved, but instrumental effort and complexity increase significantly
Solution Approach 1:
The hollow member with evacuated space provides passive thermal insulation without requiring active cooling systems. The vacuum environment inherently blocks heat transfer through conduction and convection, eliminating the need for water circulation systems, pumps, or other active cooling mechanisms, thus reducing instrumental complexity while effectively preventing heat transfer to the capillary
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 solution effectively prevents excessive heating of the liquid in the capillary, allowing for a lean and compact design while maintaining high temperature resistance and preventing outgassing or particulate shedding, thus ensuring efficient ionization without sample degradation.
Implementation Method 1
a hollow member having an internal evacuated space is located at an outer circumference of the capillary such that heat transfer from the first heatable gas flowing proximate the capillary to the liquid in the capillary is impeded
Implementation Method 2
The heated gas injected into and circulating in the ionization chamber may contact the liquid guiding capillary and transfer heat thereto
Implementation Method 3
The inert gas may also be heated in order to further promote evaporation of the spray mist
Implementation Method 4
The solvent evaporates from a charged droplet until it becomes unstable upon reaching its Rayleigh limit. At this point, the droplet deforms and emits charged jets in a process known as Coulomb fission
Data Source
AI summary
An assembly for use in an electrospray ion source includes a capillary for guiding a flow of liquid generally containing analyte(s) of interest, which is to be electrosprayed into an ionization chamber, a first tube at least partially encasing the capillary such that a first conduit for guiding a first heatable gas is created proximate the capillary and a hollow member that has an internal evacuated space and is located at the outer circumference of the capillary such that heat transfer from the first heatable gas flowing proximate the capillary to the liquid in the capillary is impeded. The assembly provides a simple and lean/compact way of preventing excessive heat transfer to the liquid in the capillary of an electrospray ion source.