Nozzle for Spraying Sublimable Solid Particles
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Solution Overview
Problem
The existing methods for cleaning surfaces using CO2 snow are limited by the formation of frost on the nozzle and object surfaces due to ultra-low temperatures, which can lead to contamination and require complex environmental control measures to prevent static electricity issues.
Innovation Solution
A nozzle design that includes a cleaning agent block for phase-changing sublimable solid particles, a nozzle block for adiabatic expansion, a carrier gas block for mixing with the cleaning agent snow, and a heater to heat the carrier gas, preventing frost formation by maintaining a high-temperature carrier gas flow around the venturi and on the object surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CO2 snow is used for cleaning at ultra-low temperature, then cleaning effectiveness is improved, but frost forms on nozzle and object surfaces
Solution Approach 1:
A heater is introduced as an intermediary device to warm the carrier gas before it mixes with the CO2 snow. This mediator prevents the ultra-low temperature CO2 snow from directly contacting and freezing the nozzle and object surfaces, while still allowing effective cleaning to occur through the mixed stream.
Solution Approach 2:
The temperature parameter of the carrier gas is changed by heating it before mixing with the CO2 snow. This parameter modification ensures that the mixed stream maintains a temperature above the frost point, preventing harmful frost formation while preserving cleaning effectiveness.
2Object-affected harmful factors
If sealed chamber with high temperature and low humidity is used to prevent frost, then frost formation is prevented, but static electricity is generated causing contaminant reattachment
Solution Approach 1:
The heated carrier gas acts as an intermediary that provides thermal protection against frost without creating the dry, static-prone environment of a sealed heated chamber. The carrier gas stream locally maintains temperature above frost point while allowing ambient humidity to prevent static electricity generation.
Solution Approach 2:
The naturally occurring ambient humidity, which would normally promote frost formation, is converted into a beneficial anti-static agent. By using heated carrier gas to prevent frost rather than heating the entire chamber, the ambient moisture remains available to dissipate static electricity, preventing contaminant reattachment.
3Reliability
If sealed chamber and auxiliary devices are used to prevent frost and static electricity, then cleaning environment is controlled, but device complexity increases
Solution Approach 1:
The functions of frost prevention and static electricity prevention are merged into a single simple mechanism: heating the carrier gas before it mixes with the CO2 snow. This eliminates the need for separate sealed chambers, humidity control systems, and anti-static devices, reducing overall system complexity while maintaining cleaning reliability.
Solution Approach 2:
The heated carrier gas stream self-regulates the local temperature to prevent frost formation, and by doing so in an open rather than sealed environment, it automatically prevents static electricity issues. The system serves multiple protective functions through a single simple action without requiring complex auxiliary members.
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 allows for effective cleaning without the need for separate environmental control, preventing frost and static electricity issues, enabling a more straightforward and efficient cleaning process in normal atmospheric conditions.
Implementation Method 1
a heater for heating at least a portion of the carrier gas supplied from the carrier gas supply source
Implementation Method 2
a cleaning agent block for phase-changing a cleaning agent introduced from a cleaning agent supply source into a snow state containing sublimable solid particles
Implementation Method 3
a nozzle block for growing the cleaning agent snow introduced from the cleaning agent block through adiabatic expansion
Implementation Method 4
CO2 snow that has removed contaminants by colliding with the surface of the object can be directly sublimed so as to leave no residue on the surface of the object
Data Source
AI summary
A nozzle for spraying sublimable solid particles and preventing frost from forming at surfaces of the nozzle. The nozzle includes: a cleaning agent block for phase-changing a cleaning agent into a snow containing sublimable solid particles; a nozzle block for growing the cleaning agent snow through adiabatic expansion and spraying the grown cleaning agent snow onto a surface of an object; a carrier gas block for supplying a carrier gas to the nozzle block to mix with the cleaning agent snow; and a heater for heating at least a portion of the carrier gas supplied from the carrier gas supply source. Fine dry ice particles and liquid CO2, passing through a solenoid valve from a CO2 reservoir tank and a pressure drop of a flow rate regulation valve, are introduced into the spray nozzle and then mixed with the carrier gas, such as N2 or purified air, and discharged.