Elevator Airflow Duct for Optical Sensor Dust Mitigation

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Solution Overview

Problem

Dusty hoistway environments interfere with the functioning of optical position reference systems in elevator systems, causing particle accumulation on the reference elements and affecting the accuracy of elevator car positioning.

Innovation Solution

An airflow duct is integrated with the elevator car to passively direct airflow towards the reference element, such as a coded tape, to prevent particle accumulation, using duct inlets and outlets to ensure airflow is directed towards the tape and maintain cleanliness without additional power sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an optical sensor system is installed in a dusty hoistway environment, then the elevator positioning function is enabled, but dust particles accumulate on the reference element interfering with optical sensing

Engineering Contradiction:

Improveoptical sensing reliabilityVSAvoiddust particle accumulation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The airflow duct is pre-configured on the elevator car to direct airflow toward the reference element before dust accumulation can interfere with optical sensing. The duct inlet faces downward to capture dust-laden air during car descent, and the outlet positioned above the optical sensor directs this airflow across the reference element to prevent particle buildup.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention utilizes pneumatic principles by creating a passive airflow system that leverages the pressure differential generated during elevator car movement. The duct captures air pressure changes during descent and directs this airflow toward the reference element, using pneumatic forces to clear dust particles without mechanical intervention.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Object-affected harmful factors

If active cleaning mechanisms are added to remove dust from the reference element, then particle accumulation is reduced, but system complexity and power consumption increase

Engineering Contradiction:

Improveparticle accumulation preventionVSAvoidcleaning system complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The system serves itself by using the natural airflow generated during normal elevator operation to clean the reference element. The duct system passively captures and redirects airflow that occurs during car descent, eliminating the need for external cleaning mechanisms, motors, or additional power sources.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention extracts and utilizes the naturally occurring airflow that happens during elevator car movement. Instead of adding active cleaning systems, the design captures and redirects the existing airflow environment to serve the cleaning function, removing the need for complex mechanical cleaning apparatus.

Inventive Principle:

Principle #2Taking out (Extraction)

3Productivity

If the duct inlet faces downward to capture airflow during car descent, then particle removal efficiency is improved, but the system may not function effectively during car ascent

Engineering Contradiction:

Improveparticle removal efficiencyVSAvoidoperation in both ascent and descent

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The duct system is designed to perform its particle removal function during both ascent and descent operations. The outlet positioning and airflow direction are configured to effectively clear the reference element regardless of the direction of car movement, making the system universally effective for both upward and downward travel.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 airflow duct effectively prevents particle accumulation on the reference element, ensuring accurate elevator car positioning and improving the reliability of the position reference system without requiring additional power or maintenance.

Implementation Method 1

The airflow duct is configured to passively direct an airflow toward the reference element to prevent accumulation of particles on the reference element

Methodology Applied

Scientific EffectAirflow: Convection

Data Source

PatentUS20250019203A1Dust mitigation for optical position reference system of an elevator system

Publication Date: 2025.01.16 OTIS ELEVATOR CO

AI summary

A position reference system of an elevator system includes a reference element having a fixed position in a hoistway of the elevator system, and an optical sensor configured to move along the hoistway with an elevator car of the elevator system and configured to transmit a signal to the reference element to determine the position of the elevator car. An airflow duct is configured to move along the hoistway with the elevator car. The airflow duct is configured to passively direct an airflow toward the reference element to prevent accumulation of particles on the reference element.