Fiber Counting Apparatus Using Laser and Quadrupole Electrodes
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Solution Overview
Problem
Existing fiber counting devices in the workplace are limited by inefficient instrument design, leading to inaccurate and time-consuming detection of harmful airborne fibers, such as asbestos, which hampers their effectiveness in providing timely warnings to workers.
Innovation Solution
A solid-state laser light source and quadrupole electrode system are used to create a detection zone within a flow passageway, where the laser beam illuminates a larger area, causing fibers to oscillate and scatter light, which is then detected by a photo detector, producing a pulse train that indicates fiber concentration, allowing for rapid and accurate counting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a traditional fiber counting device is used, then the instrument can detect fibers, but the measurement time is long (20 minutes) and the sensing area is limited
Solution Approach 1:
The patent transitions from a point-based sensing approach to a planar sensing area by introducing a laser beam that illuminates a two-dimensional cross-sectional area of the flow passageway. This dimensional expansion allows simultaneous detection of multiple fibers across the beam path, increasing productivity without requiring longer measurement times.
Solution Approach 2:
The patent uses optical copying by detecting light scattered from fibers as they pass through the illuminated plane. Instead of physically capturing or manipulating each fiber, the system creates an optical signature (scattered light pattern) that can be detected and counted, enabling rapid measurement across a larger effective sensing area.
2Area of stationary object
If the light beam cross-sectional area is increased to illuminate more area, then the sensing area increases, but the light intensity per unit area may decrease
Solution Approach 1:
The patent introduces dynamic oscillation of fibers through applied electric fields, causing fibers to move rapidly through the illuminated plane. This dynamic motion ensures that fibers continuously sample different regions of the light beam, maximizing the utilization of the available light intensity across the expanded sensing area while maintaining detection sensitivity.
Solution Approach 2:
The oscillating electric field applies periodic forcing to the fibers, creating a regular back-and-forth motion pattern. This periodic action ensures consistent sampling of the light beam across the entire illuminated area, maintaining uniform detection sensitivity throughout the expanded sensing zone.
3Measurement precision
If fibers are made to oscillate through electric field, then detection accuracy improves, but device complexity increases
Solution Approach 1:
The quadrupole electrode system serves multiple functions: it generates the oscillating electric field for fiber motion, provides field uniformity across the sensing area, and enables both orientation control and oscillation induction. This multi-functionality achieves improved measurement precision without proportionally increasing device complexity, as a single electrode configuration accomplishes multiple detection-enhancing tasks.
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 improved design increases the illuminated sensing area by 20-fold, reducing measurement time from 20 minutes to 1 minute, enabling faster detection of hazardous fiber concentrations and providing timely alerts for worker protection.
Implementation Method 1
The fibers carried in the gas will scatter light from the laser beam and a photo detector is provided to detect scattered light in a detection zone
Implementation Method 2
An electrode system, preferable a quadrupole electrode system, is provided to produce an oscillating electric field to cause the fibers to oscillate in the detection zone
Data Source
AI summary
The present disclosure has an apparatus for detecting fibers in a gas flowing along a passageway. A laser beam is provided at one end of the passageway and the beam is directed along a length of the passageway through which the gas flows. An electrode system, as disclosed, a quadrupole electrode system is mounted along the passageway to cause fibers carried in the gas to oscillate in a detection zone. A photo detector is positioned laterally of the passageway and detects light scattered by the oscillating fibers and projected through an opening in the passageway to provide an output signal that is a function of the light scattered by the fibers in the detection zone.