Light Grid Overpressure Unit for Dust Protection

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Solution Overview

Problem

Conventional light grids mounted below conveyor belts are prone to contamination from conveyor belt abrasion, loose parts, and dust, which compromises their operational readiness.

Innovation Solution

A light grid with an overpressure unit surrounding the light transmitting and receiving units, providing compressed air through coaxially arranged openings, creating a laminar flow that prevents dirt from reaching the optical surface, and a cylindrical design that protects against mechanical damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the light grid is mounted below the conveyor belt to enable measurement, then the measuring capability is improved, but the optical surface becomes vulnerable to contamination from conveyor belt abrasion, loose parts, and dust

Engineering Contradiction:
Improveoperational readinessVSAvoidcontamination of optical surface
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A housing is introduced as an intermediary protective structure that encloses the light grid's optical components. The housing physically separates the sensitive optical surface from the contaminated environment below the conveyor belt, allowing the light grid to maintain its measuring capability while protecting against abrasion, loose parts, and dust contamination.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The light grid is extracted from direct exposure to the contaminated environment by placing it inside a protective housing. The housing acts as a barrier that removes the harmful contamination factors from direct contact with the optical surface, while still allowing the light grid to function through the housing material.

Inventive Principle:
Principle #2Taking out (Extraction)

2Object-affected harmful factors

If the light grid is mounted in a protected position, then contamination is reduced, but access to light transmitting units and receiving units becomes more difficult

Engineering Contradiction:
Improvecontamination of optical surfaceVSAvoidaccess to light transmitting units and receiving units
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The housing is designed with separable sections or access points that allow technicians to open or remove parts of the housing to access the light transmitting units and receiving units for maintenance and replacement, while maintaining the protective enclosure during normal operation.

Inventive Principle:
Principle #1Segmentation

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 contamination of the optical surface, extending the operational readiness of the light grid without complex mechanical efforts and providing additional mechanical protection.

Implementation Method 1

By supplying the compressed air on one side, it is possible to easily create a laminar flow in the overpressure unit and to achieve a constant outflow from the openings.

Methodology Applied
Scientific EffectLaminar flow: Laminar Flow

Data Source

PatentEP2884310B1Light grid
Publication Date: 2016.06.08 SICK AG
  • EP2884310B1 patent drawingFigure 1~2a
  • EP2884310B1 patent drawingFigure 2
  • EP2884310B1 patent drawingFigure 3~4

AI summary

The invention relates to a light grid (1) with light transmitting units (2) arranged in a series for emitting light beams and/or light receiving units (10) for receiving the light beams, a housing (3) that contains the light transmitting units and/or light receiving units and has a longitudinal side through which the light beams are transmitted, and is provided with an overpressure unit (4) for supplying compressed air, wherein the overpressure unit has openings (6) that are arranged coaxially to the optical axes of the light transmitting units or light receiving units, and an overpressure connection (4a) and is designed such that introduced compressed air can be directed towards the openings and can only escape through these openings.