Two-Compartment Heat Transfer Unit for Hazardous Air Isolation

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Solution Overview

Problem

Conventional heat transfer units used in hazardous environments require costly and complex remedial measures to prevent explosions and ignition, such as explosion-proof components and energy-limiting devices, which reduce reliability and increase complexity.

Innovation Solution

A heat transfer unit is designed with two sealed compartments: one for hazardous air circulation with non-ignition components and another for potential ignition sources, where the motor and condenser are isolated from hazardous air, maintaining a higher internal pressure in the compartment with ignition sources to prevent hazardous air infiltration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional remedial approaches (explosion-proof hardware, energy-limiting devices, relocating spark-producing components) are used, then safety in hazardous environments is improved, but cost and device complexity increase

Engineering Contradiction:
ImprovesafetyVSAvoidcomplexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The housing is divided into a first compartment containing ignition sources (motor, switches, relays) and a second compartment containing non-ignition components (condenser, evaporator, piping). This segmentation isolates potential ignition sources from the hazardous environment while using standard components, eliminating the need for expensive explosion-proof hardware and energy-limiting devices.

Inventive Principle:
Principle #1Segmentation

2Reliability

If explosion-proof hardware and enclosures are used, then safety in hazardous environments is improved, but cost increases

Engineering Contradiction:
ImprovesafetyVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By segmenting the housing into two compartments with the ignition sources isolated in the first compartment, the patent enables use of standard, non-explosion-proof components. This eliminates the need for costly explosion-proof hardware and enclosures while maintaining safety through physical separation and pressure differential.

Inventive Principle:
Principle #1Segmentation

3Reliability

If energy-limiting devices are incorporated, then safety in hazardous environments is improved, but device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoidcomplexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The compartmentalization approach eliminates the need for energy-limiting devices by physically isolating ignition sources from the hazardous environment. Standard components without energy-limiting devices can be used in the first compartment, reducing device complexity while maintaining safety through spatial separation and pressure control.

Inventive Principle:
Principle #1Segmentation

4Device complexity

If compartments are not isolated from each other, then device complexity is reduced, but hazardous air can enter the first compartment causing safety issues

Engineering Contradiction:
ImprovecomplexityVSAvoidsafety
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The housing is segmented into two isolated compartments with sealed walls. The first compartment contains ignition sources protected from hazardous air, while the second compartment interfaces with the hazardous environment. This segmentation maintains safety while keeping the overall device structure relatively simple.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A pressure differential is maintained between the two compartments, with the first compartment held at a higher internal pressure than the second compartment. This parameter change prevents hazardous air from entering the first compartment through the sealed walls, providing passive safety without complex active control systems.

Inventive Principle:
Principle #35Parameter changes

5Device complexity

If standard components are used without isolation, then cost and complexity are reduced, but sparks and hot surfaces can cause explosions or ignition in hazardous environments

Engineering Contradiction:
ImprovecomplexityVSAvoidignition risk
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

Standard components including motor, switches, and relays are placed in the first compartment isolated from the hazardous environment in the second compartment. This segmentation allows use of standard components without explosion-proof ratings while preventing their sparks and hot surfaces from causing ignition, as hazardous air cannot penetrate the sealed compartment walls.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first compartment is maintained at a higher internal pressure than the second compartment, creating a pressure differential that prevents hazardous air from entering the first compartment. This parameter control eliminates the ignition risk from standard components while keeping the system simple and cost-effective.

Inventive Principle:
Principle #35Parameter changes

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 configuration allows for safe operation in hazardous environments without the need for explosion-proof or energy-limiting components, reducing costs and complexity while maintaining reliability by preventing hazardous air from entering the compartment with ignition sources.

Implementation Method 1

the heat transfer unit is configured such that, during operation, an interior of the first compartment is maintained at an internal pressure that is higher than an internal pressure in the second compartment

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

a second compartment comprising an ambient hazardous air inlet, an ambient hazardous air outlet, a condenser

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 3

a first compartment, configured for coupling to and removing heat from the enclosure, the first compartment having therein an evaporator

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentEP3060857B1Hazardous location heat transfer unit
Publication Date: 2021.11.17 KOOLTRONIC INC
  • EP3060857B1 patent drawingFigure 1
  • EP3060857B1 patent drawingFigure 2
  • EP3060857B1 patent drawingFigure 3A~3B

AI summary

A two chamber heat transfer unit configured such that hazardous air can circulate through one of the chambers and potential ignition source components are contained in another chamber through which the gas to be heated or cooled will circulate.