Variable Cascade Impactor for Flow Adaptation

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Solution Overview

Problem

Existing cascade impactors have fixed bore diameters and plate spacings, limiting their ability to adapt separation capacity to varying conditions, particularly in handling different volume flows without significant pressure increases.

Innovation Solution

A variable cascade impactor design featuring a first stage with a spring-loaded baffle that adjusts distance from the gas inlet plate, allowing for increased gas flow at low pressure, followed by a second stage with a fixed baffle where gas flows in two directions, enhancing separation efficiency by varying the angle and distance of impact surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If fixed bore diameter and plate spacing are used in cascade impactor stages, then manufacturing is simplified, but separation capacity cannot be adapted to varying volume flows without significant pressure increases

Engineering Contradiction:
Improveseparation capacityVSAvoidstructure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The baffle plate is made movable rather than fixed, allowing it to adjust its position dynamically. The distance between the baffle plate and the plate with bores can be varied to adapt to different volume flows, resolving the contradiction between adaptability and structural simplicity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The key parameter being changed is the plate spacing (distance between baffle plate and plate with bores). By making this parameter variable through the movable baffle plate design, the separation capacity can be adapted to different operating conditions while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If distance between baffle wall and bores is minimized for high separation efficiency, then separation performance improves, but pressure increase becomes significant at large volume flows

Engineering Contradiction:
Improveseparation efficiencyVSAvoidpressure increase
Core Design Contradiction:
Manufacturing precisionVSStress or pressure

Solution Approach 1:

The baffle plate position is made dynamic rather than fixed. At low volume flows, the baffle plate maintains a minimal distance from the bores for high separation efficiency. At large volume flows, the baffle plate can move to increase the distance, allowing large volume flows to pass through effectively without a large increase in pressure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses the gas flow itself to adjust the baffle plate position. The spring-loaded mechanism allows the baffle plate to move automatically in response to pressure changes caused by varying volume flows, eliminating the need for external control systems.

Inventive Principle:
Principle #25Self-service

3Productivity

If spring-loaded movable baffle plate is used to increase volume flow capacity, then pressure increase is reduced, but device complexity increases

Engineering Contradiction:
Improvevolume flow capacityVSAvoidstructure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The spring-loaded mechanism is a passive, self-regulating system that uses the gas flow pressure itself to move the baffle plate. This eliminates the need for motors, sensors, or control systems, keeping the added complexity minimal while significantly increasing volume flow capacity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses pneumatic pressure from the gas flow to actuate the baffle plate movement. The spring-loaded design converts pressure changes into mechanical displacement, providing a simple yet effective way to increase volume flow capacity without complex mechanical or electronic control systems.

Inventive Principle:
Principle #29Pneumatics and hydraulics

4Manufacturing precision

If jet strikes baffle wall at high speed for effective particle separation, then separation efficiency improves, but device complexity increases due to additional stages

Engineering Contradiction:
Improveseparation efficiencyVSAvoidnumber of stages
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention combines two impactor stages into a compact arrangement where the first stage uses a movable baffle plate and the second stage uses a fixed baffle plate. The gas flow sequentially strikes both baffle plates, and the two stages are integrated in a way that maintains high separation efficiency while minimizing the overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention utilizes the spatial arrangement and angular orientation of the baffle plates to achieve effective separation. By orienting the baffle plates at specific angles (60 to 120°, particularly 85 to 95°) and arranging them in sequence, the gas jet strikes the surfaces effectively without requiring excessive additional space or complex structures.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 design enables high separation efficiency across varying volume flows without substantial pressure increases, effectively separating droplets and particles by optimizing the gap distance and angle between impact surfaces, allowing for efficient operation in both low and high flow conditions.

Implementation Method 1

the first baffle (4) is spring-loaded (3) and is therefore at a small distance from the bores (2) at low volume flows too

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

the gas speed in the variable gap of the first stage is used to throw the droplets or solid particles in the gas at high speed onto a second wall (5)

Methodology Applied
Scientific EffectImpaction: Impact Force

Data Source

PatentEP3174614B1Cascade impactor
Publication Date: 2019.09.11 POLYTEC PLASTICS GERMANY
  • EP3174614B1 patent drawingFigure 1

AI summary

The invention relates to a cascade impactor having a first stage comprising a plate (2) with fixed bores as gas inlet and at least a first impact wall (4) with a variable distance from the plate (2) as well as at least a second stage having a fixed second impact wall (5), which is arranged in the flow direction downstream of the first impact wall (4).