Movable Wall Fog Generator with Propellant Gas

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Solution Overview

Problem

Fog-generating devices face limitations in rapid fog generation capacity, orientation flexibility, and complex purging mechanisms, which restrict their effectiveness in security applications and require skilled maintenance.

Innovation Solution

A fog-generating device with a movable wall reservoir and a heat exchanger, driven by a propellant gas that expands to expel fog-generating material, and includes depressurizing means for purging the heat exchanger, allowing for a removable housing for easy maintenance and orientation flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a pump is used to drive fog-generating liquid from reservoir to heat exchanger, then the device can generate fog, but the fog generation capacity is restricted due to pump capacity limitations and battery power constraints

Engineering Contradiction:
Improvefog generation capacityVSAvoidpump and power system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical pump system with a chemical/physical system using propellant gas expansion. The propellant gas (stored under pressure) automatically expands to drive the movable wall and expel fog-generating liquid through the heat exchanger, eliminating the need for mechanical pumps and power sources while dramatically increasing fog generation capacity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the phase transition of propellant gas from liquid to gas state. The propellant is stored as a liquid under pressure in the reservoir, and when released, it rapidly expands to gas, generating the force needed to drive the movable wall and expel fog liquid without any mechanical moving parts

Inventive Principle:
Principle #36Phase transitions

2Adaptability or versatility

If the device is oriented in fixed positions, then the reservoir structure is simple, but the device lacks freedom for orienting during transport and installation

Engineering Contradiction:
Improveorientation freedomVSAvoidreservoir structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces a movable wall (piston) within the reservoir that can move freely in response to propellant gas expansion. This dynamic element allows the fog-generating liquid to be expelled regardless of the device's orientation, as the movable wall automatically adjusts its position to push the liquid toward the heat exchanger outlet, providing complete orientation freedom

Inventive Principle:
Principle #15Dynamics

3Productivity

If propellant gas is used to drive fog-generating liquid, then fog generation speed increases, but the device requires complex purging mechanisms to remove residual liquid from the heat exchanger

Engineering Contradiction:
Improvefog generation speedVSAvoidpurging mechanism complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements a self-purging mechanism where the propellant gas, after expelling the fog-generating liquid, automatically flows back through the heat exchanger to purge any residual liquid. The same propellant gas that provides the driving force also performs the cleaning function, eliminating the need for separate purging systems

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent ensures continuous useful action by having the propellant gas perform multiple functions in sequence: first expanding to drive the movable wall, then flowing through the heat exchanger to purge residual liquid, and finally being vented. This continuous flow of propellant gas maximizes system efficiency without requiring idle periods or additional components

Inventive Principle:
Principle #20Continuity of useful action

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

Enables rapid fog generation, increased orientation freedom, and simplified maintenance by using a movable wall reservoir and depressurizing means, enhancing the device's performance and usability in security applications.

Implementation Method 1

Expansion the liquefied propellant gas expands to its gas phase and drives the fog-generating liquid from the reservoir to the heat exchanger

Methodology Applied
Scientific EffectPhase change (liquid to gas expansion): Phase Change

Implementation Method 2

a propellant gas drives said movable wall to expel the fog-generating material from the reservoir

Methodology Applied
Scientific EffectPressure expansion: Pressure Increase

Implementation Method 3

driving a fog-generating substance through a heat exchanger; upon which the fog-generating substance is converted into the vapour phase

Methodology Applied
Scientific EffectVaporization: Evaporation

Implementation Method 4

the vapour may condense upon expansion into tiny liquid droplets suspended in the air as an aerosol, with the formation of a fog

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP2860486B1Fog-generating device comprising a movable wall in a reservoir
Publication Date: 2015.12.09 BANDIT NV
  • EP2860486B1 patent drawingFigure 1
  • EP2860486B1 patent drawingFigure 2~3
  • EP2860486B1 patent drawingFigure 4

AI summary

The present invention relates to a fog-generating device comprising: a propellant gas (1); a reservoir (4) comprising a movable wall (2) and a fog-generating material (3); and a heat exchanger(9) ; wherein said propellant gas (1) drives said movable wall (2) to expel the fog-generating material (3) from the reservoir (4) to the heat exchanger (9). The present invention also provides a removable housing (6) for such a device.