Compressed-Air Dehumidifier with Counter-Flow Heat Recovery

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Solution Overview

Problem

Existing dehumidifiers for compressed air flows, which typically use two heat exchangers, face inefficiencies in energy usage and residual dampness reduction due to design limitations, leading to increased costs and reduced compactness.

Innovation Solution

Incorporating a third chamber and external dehumidifying means between the heat exchangers to enhance dehumidification efficiency, with a counter-flow configuration and a demister in the second chamber to intercept condensed moisture, improving compactness and energy efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a second channel is completely adjacent to the second heat exchanger to allow air flow passage, then the dehumidifier structure is compact, but the air flow is cooled by the heat exchanger wall which reduces dehumidification efficiency and increases residual dampness

Engineering Contradiction:
Improvedehumidifier compactnessVSAvoiddehumidification efficiency
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The patent divides the internal structure into distinct chambers: a first chamber for the first heat exchanger, a second chamber for the second heat exchanger, and a third chamber positioned between them. This segmentation prevents unwanted thermal interaction while maintaining compact overall structure, resolving the contradiction between compactness and dehumidification efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The third chamber acts as an intermediary space between the first and second chambers. It allows the dehumidified air flow to pass from the second chamber back to the first chamber without direct contact with the second heat exchanger wall, preventing unintended cooling while maintaining the compact counter-flow configuration.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of energy

If two heat exchangers are used for pre-cooling and heating functions, then energy saving is achieved, but the apparatus complexity and cost increase

Engineering Contradiction:
Improveenergy consumptionVSAvoidheat exchanger configuration
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The first heat exchanger serves dual functions: pre-cooling the incoming damp air flow and subsequently heating the dehumidified air flow. This multi-functionality reduces the need for additional separate components, lowering apparatus complexity while maintaining energy efficiency through heat recovery.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses the cold dehumidified air flow itself to pre-cool the incoming damp air in the first heat exchanger, and then uses this same pre-cooled air to be heated by the first heat exchanger. The system essentially serves itself through internal heat exchange, reducing external energy requirements without adding complex components.

Inventive Principle:
Principle #25Self-service

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 solution allows for a more compact, energy-efficient dehumidification process with reduced residual dampness, achieving higher dehumidification effectiveness without the need for additional costly components or complex constructions.

Implementation Method 1

a first heat exchanger for pre-cooling and successively heating said gas flow, and comprising two distinct conduit assemblies for the reciprocal heat exchange

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

The first function is that of pre-cooling the compressed air flow before entering the first exchanger... The second function consists in heating the compressed air exiting the second heat exchanger

Methodology Applied
Scientific EffectCounter-flow heat exchange: Heat Exchanger

Implementation Method 3

While passing by said first branch, the compressed air flow is cooled up to a value lower than the dew point; as a direct and desired consequence the dampness contained in the air is condensed and therefore changed into water

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 4

Then, after having been separated from the air, because of gravity, said water is collected in the lower part by means of appropriate collecting means

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 5

with a counter-flow configuration and a demister in the second chamber to intercept condensed moisture

Methodology Applied
Scientific EffectInterception: Filter (physical)

Data Source

PatentEP2827972B1Improved apparatus for the dehumidification of an air flow preferably a compressed air flow
Publication Date: 2020.05.06 PARKER HANNIFIN MFG SRL
  • EP2827972B1 patent drawingFigure 1
  • EP2827972B1 patent drawingFigure 2~3
  • EP2827972B1 patent drawingFigure 4~5

AI summary

Apparatus for the dehumidification of a gas flow, with an outer box and an inlet port for the damp air and an outlet port for the dehumidified air, a first pre-cooling heat exchanger, and a second heat exchanger downstream of the first exchanger and also passed by a refrigerating fluid, a dampness collection chamber arranged downstream of the second exchanger; it is provided: a second chamber downstream of the collection chamber and connected to the outside of box by means of an emission mouth; a third chamber not communicating to said second chamber but connected, on one side, to the conduits of the first exchanger, and on the other side connected to the outside of the box by a respective inlet mouth. It is defined a return path from the second to the first exchanger, comprising a first leg which passes through the collection chamber, a second leg which passes through the second chamber and the respective emission mouth, and a third leg which passes through the third chamber; preferably the conduits fed by the gas flow coming from the third chamber are in a counter-flow way in relation with the gas inlet conduits arranged in the first exchanger.