Aerodynamic Anti-Rotation Device for Industrial Fans

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Solution Overview

Problem

Industrial fans often experience reverse rotation due to reverse air flow, leading to potential damage to motor and drive components, and existing mechanical anti-rotation pins are prone to wear, vibration, and costly retrofitting.

Innovation Solution

An aerodynamic anti-rotation device using a contactless L-shaped lever with a pulley and flat plate that disengages during fan operation and locks using gravity when airflow stops, preventing reverse rotation without being part of the fan rotor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mechanical anti-rotation pin is used to prevent reverse rotation, then the fan is protected from damage, but the device is prone to wear, vibration, and costly retrofitting

Engineering Contradiction:

Improveprotection from reverse rotation damageVSAvoidmechanical wear and retrofitting cost

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the conventional mechanical anti-rotation pin with an aerodynamic anti-rotation device that uses airflow forces instead of mechanical contact. The aerodynamic lever utilizes air pressure differential to engage and disengage, eliminating mechanical wear and vibration associated with traditional pins that rotate with the fan shaft.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The device employs aerodynamic forces generated by fan airflow to actuate the anti-rotation mechanism. During fan operation, airflow creates pressure differential that moves the aerodynamic lever to a disengaged position. When airflow stops, gravity returns the lever to a locked position, providing reverse rotation prevention without mechanical wear.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Reliability

If a mechanical anti-rotation pin is assembled with the fan shaft, then reverse rotation is prevented, but the device is subject to rotation, wear, and vibration

Engineering Contradiction:

Improvereverse rotation preventionVSAvoidrotation, wear, and vibration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The aerodynamic anti-rotation device is extracted from the rotating fan shaft system and mounted independently on the housing. The aerodynamic lever does not rotate with the fan but instead uses airflow forces to engage/disengage, eliminating the harmful effects of rotation, wear, and vibration that affect mechanically coupled pins.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The anti-rotation function is segmented from the fan shaft rotation system. The aerodynamic lever operates independently on the housing while the fan blades rotate freely on the shaft. This segmentation allows the anti-rotation mechanism to remain stationary while still preventing reverse rotation through aerodynamic actuation.

Inventive Principle:

Principle #1Segmentation

3Reliability

If a conventional mechanical anti-rotation pin is used, then reverse rotation is locked, but costly retrofitting is required

Engineering Contradiction:

Improvereverse rotation lockingVSAvoidretrofitting cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The aerodynamic lever acts as an intermediary mechanism that translates airflow forces into anti-rotation locking action. By mounting the device on the housing rather than the shaft, it provides a cost-effective retrofit solution that doesn't require modification of the rotating fan components, simplifying installation and reducing retrofitting costs.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Prevents reverse rotation of industrial fan blades effectively, reducing the risk of motor and gearbox failures while being independent and non-intrusive, thus avoiding costly retrofitting and maintenance issues.

Implementation Method 1

when the fan starts, the pin utilizes airflow to dis-engage with the fan, and allow fan to rotate freely

Methodology Applied

Scientific EffectAerodynamic force: Drag

Implementation Method 2

When the fan stops, there is no airflow and the aero dynamic anti-rotation pin returns to lock position using gravity, which prevents the fan from reverse rotation

Methodology Applied

Scientific EffectGravity: Gravitation

Data Source

PatentUS11867191B2Aerodynamic anti-rotation device

Publication Date: 2024.01.09 SAUDI ARABIAN OIL CO

AI summary

An anti-rotation device configured to prevent a plurality of blades of the industrial fan from rotating. The anti-rotation device includes a movable member and a non-movable member, wherein the movable member is slidable relative to the blades between two positions, an unlocked position that substantially permits the plurality of blades to rotate and a locked position that substantially prevents the plurality of blades from rotating. The movable member is movable in a direction substantially perpendicular to a direction of rotation of the blades. In one embodiment, the anti-rotation device includes a substantially L-shaped lever having a long side and a short side, a pulley operatively connected to the L-shaped lever at a point where the long side and the short side meet, and a substantially flat plate attached to one end of the short side of the L-shaped lever.