Magnetic Coupler for Centrifugal Fan Damper Seating

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Solution Overview

Problem

Centrifugal fans in air delivery systems face backflow issues when one fan becomes inoperative, leading to reduced pressure and noise due to conventional damper solutions that are mechanically complex, noisy, and prone to cracking at low speeds.

Innovation Solution

A magnetic coupler is used to securely seat a damper against the fan wheel backplate during low flow conditions, preventing backflow without affecting normal operation, and automatically switching to a closed position when reverse pressure differential occurs, using a magnetic attraction force that decouples at high reverse pressure differentials to allow backflow obstruction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional damper is placed at the fan inlet to prevent backflow, then backflow prevention is achieved, but fan performance is reduced and noise increases due to flow disturbances

Engineering Contradiction:

Improvebackflow preventionVSAvoidnoise and flow disturbances

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A magnetic coupler acts as an intermediary between the damper and the fan wheel backplate, providing a non-contact force to hold the damper in the open position during normal operation, eliminating flow disturbances and noise while maintaining backflow prevention capability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The magnetic coupling force replaces conventional mechanical linkages, springs, and actuators that were previously required to hold the damper in position, eliminating mechanical complexity and the associated flow disturbances and noise

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a conventional damper is used with mechanical linkages and springs to prevent backflow, then backflow obstruction is achieved, but device complexity increases

Engineering Contradiction:

Improvebackflow obstructionVSAvoidmechanical complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The magnetic coupler replaces complex mechanical linkages, centrifugal actuators, and springs with a simple magnetic field-based coupling mechanism, dramatically reducing device complexity while maintaining reliable backflow obstruction functionality

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The magnetic coupling mechanism extracts and eliminates the need for complex mechanical components, retaining only the essential damper structure and the magnetic coupler, thereby simplifying the overall device

Inventive Principle:

Principle #2Taking out (Extraction)

3Stability of the object's composition

If the magnetic force is strong enough to keep the damper fully seated during low speed operation, then damper stability is improved, but the damper cannot move from open to closed position when backflow occurs

Engineering Contradiction:

Improvedamper seating stabilityVSAvoiddamper movement capability

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The magnetic force parameter is precisely calibrated to change its effectiveness based on operating conditions: strong enough during low-speed operation to prevent damper rocking and maintain stability, but weak enough during backflow events to allow the damper to move to the closed position

Inventive Principle:

Principle #35Parameter changes

4Ease of operation

If the damper is allowed to rock on the shaft during low speed operation, then ease of operation is maintained, but damper cracking occurs due to moment created by weight

Engineering Contradiction:

Improvedamper rotational freedomVSAvoiddamper structural integrity

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The magnetic coupling force acts as a counterbalancing force that opposes the moment created by the damper's weight during low-speed operation, preventing the damper from rocking on the shaft and avoiding structural cracking

Inventive Principle:

Principle #8Anti-weight (Counterweight)

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 effectively prevents backflow through inoperative centrifugal fans, reduces noise and turbulence, and mitigates damper cracking risks by maintaining the damper fully seated during low-speed operations, ensuring efficient airflow and pressure maintenance.

Implementation Method 1

A magnetic coupler is used to securely seat a damper against the fan wheel backplate during low flow conditions

Methodology Applied

Scientific EffectMagnetic attraction force: Magnetism

Implementation Method 2

using a magnetic attraction force that decouples at high reverse pressure differentials to allow backflow obstruction

Methodology Applied

Scientific EffectMagnetic force decoupling under reverse pressure: Magnetism

Data Source

PatentUS11603848B2Automated fan inlet damper closure apparatus

Publication Date: 2023.03.14 ACOUSTIFLO

AI summary

Embodiments of the inventive technology include a centrifugal fan having a damper repositionable between a closed position and a fully seated open position, and a magnetic coupler that serves to fully seat that damper it its open configuration, so as to prevent undesired effects such as slippage and/or rocking of that damper relative to rotatable componentry against which it is pressed, during operation of the fan. The coupler may be configured so that the damper may decouple from rotatable componentry, e.g., upon a certain reverse pressure differential, and translate to a closed position.