Automated Finned Heat Exchanger Cleaning with Pneumatic Jet Nozzles
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Solution Overview
Problem
Current methods for automated cleaning of lamellar heat exchangers face inefficiencies due to high water usage, reduced cleaning effectiveness with depth, potential damage from water jets, and increased costs, leading to suboptimal heat dissipation and output throttling.
Innovation Solution
A method utilizing a guide unit with movable jet nozzles and a carrier gas, such as compressed air, with a small amount of liquid as the blasting agent, ensuring thorough and resource-efficient cleaning, using convergent-divergent Laval nozzles and a two-stage cleaning process to adapt to different conditions and geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If water jet nozzles are used for cleaning finned heat exchangers, then cleaning effect on the front side is good, but cleaning effectiveness decreases with increasing depth and passage values remain poor
Solution Approach 1:
The invention uses compressed air (gas) instead of water for the blasting medium, creating a pneumatic cleaning system. The carrier gas is supplied through supply hoses with a pressure of at least 2 bar, and a small amount of liquid (less than 1% of air supplied) is added as blasting agent. This pneumatic approach eliminates the braking effect that water experiences in narrow channels, allowing the cleaning medium to penetrate the entire depth of the heat exchanger effectively.
Solution Approach 2:
The invention changes the physical state and properties of the cleaning medium from liquid water to compressed gas with minimal liquid additive. This parameter change (from liquid to gas phase) allows the cleaning medium to achieve supersonic speeds, penetrate deep into the heat exchanger channels, and maintain cleaning effectiveness throughout the entire depth rather than just the front side.
2Manufacturing precision
If water jet nozzles are used with high pressure, then cleaning effect improves, but damage to sensitive fins increases
Solution Approach 1:
The invention replaces water-based hydraulic cleaning with pneumatic cleaning using compressed air as the carrier gas. Gas at controlled pressure (at least 2 bar, preferably up to 16 bar) provides sufficient cleaning force while being inherently softer and less damaging to sensitive fin structures compared to high-pressure water jets.
Solution Approach 2:
The invention changes the cleaning medium from liquid to gas phase, which fundamentally alters the interaction characteristics with the fin surfaces. The gaseous carrier gas with minimal liquid additive provides cleaning action through pressure and velocity without the high density and impact force of water, thereby reducing mechanical damage to sensitive fins while maintaining effective dirt removal.
3Manufacturing precision
If compressed air with small amount of liquid is used as blasting medium, then cleaning effectiveness improves throughout depth, but device complexity increases
Solution Approach 1:
The invention introduces a mixing chamber as an intermediary component where the carrier gas and blasting agent (liquid) are combined before being supplied to the jet nozzles. This mixing chamber ensures proper mixing and distribution of the cleaning medium, allowing effective penetration and cleaning throughout the heat exchanger depth while maintaining a manageable device structure through functional integration.
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 method enables quick, complete, and cost-effective cleaning of lamellar heat exchangers with improved resource efficiency and reduced risk of damage, maintaining high cleaning quality and heat dissipation performance.
Implementation Method 1
The jet nozzles used here are preferably designed as convergent-divergent Laval nozzles. The high jet speed, which can reach supersonic speed, ensures that the jet medium penetrates the heat exchanger in its entire depth.
Implementation Method 2
a liquid, preferably water, are supplied as the blasting agent, the amount of water supplied being less than 1%, preferably less than 0.30% of the amount of air supplied
Data Source
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AI summary
The invention relates to a method for the automated cleaning of lamellar heat exchangers (13) and other sensitive surfaces, wherein a moving device (10), preferably moving on the rollers (4) or skids, is moved up and down on a guide unit (9) consisting of at least one and preferably two guide rails (1), which moving device has attached to it a support arm (5) to which are attached at least one and preferably multiple spray nozzles (6) such that these nozzles are moved by the moving device (10) by means of an additional drive unit (2), preferably via a roller or gear wheel (8) attached at another end next to the guide unit (9), wherein supply hoses (19) pressurized to at least 2 bar supply a carrier gas, preferably compressed air, and as the spraying medium a liquid, preferably water, wherein the supplied water quantity is less than 1%, preferably less than 0.30% of the supplied air quantity.