Optical Particle Counter Without Air Pump
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical particle counters require powerful air-pumps and particle filters, leading to increased size, current consumption, and manufacturing complexity, while existing low-cost particle sensors lack single particle sensitivity and accuracy in counting and sizing.
Innovation Solution
A low-cost apparatus with a single detector and a dual optical sensing zone, using a single reflector or refractor to direct scattered light to integral photosensitive areas, allowing for accurate particle counting and sizing without an air-pump or particle filter, and utilizing a simple, injection-moulded plastic design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical particle counters use powerful air-pumps and particle filters to ensure accurate particle detection, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent removes the air-pump and particle filter components from the conventional OPC system. The invention uses natural air flow or passive diffusion to deliver particles to the sensing zone, eliminating the need for mechanical pumping and filtration systems while maintaining particle detection capability.
Solution Approach 2:
The patent replaces the mechanical air-pump system with an optical-based detection approach. By using a laser beam and photodetector arrangement that can detect particles in a larger volume without requiring mechanical air movement, the system substitutes mechanical particle delivery with optical particle detection.
2Reliability
If conventional optical particle counters use particle filters to protect the air-pump, then reliability is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent eliminates the particle filter component entirely by removing the air-pump system that required protection. Without mechanical pumping, there is no component vulnerable to particulate contamination, making the filter unnecessary.
Solution Approach 2:
The system design inherently protects itself from contamination issues by avoiding mechanical components that would be damaged by particles. The optical detection system is naturally resistant to particulate damage, eliminating the need for protective filtration.
3Measurement precision
If conventional optical particle counters use narrow sample tubes to define the sensing zone, then measurement precision is improved, but device complexity and current consumption increase
Solution Approach 1:
The patent replaces the mechanically defined narrow sample tube with an optically defined sensing zone. A laser beam creates a virtual sensing volume that can be precisely controlled through optical focusing without requiring physical constriction, eliminating the need for high-pressure air flow through narrow tubes.
Solution Approach 2:
The patent transitions from a one-dimensional narrow tube definition to a three-dimensional optically defined sensing volume. The laser beam creates a volumetric sensing zone that can detect particles throughout a larger space without requiring narrow mechanical confinement, reducing pressure drop and power consumption.
4Ease of manufacture
If low-cost particle sensors use simplified detection zones, then manufacturing cost is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent uses an optically defined sensing zone created by a laser beam instead of complex mechanical structures. This optical approach provides precise particle detection capability while maintaining simple, low-cost manufacturing using standard optical components.
Solution Approach 2:
The patent employs a dual photodetector arrangement that serves multiple functions: detecting particle presence, determining particle size through light scattering patterns, and providing spatial information. This multi-functional detection system achieves high measurement precision with simple, universal optical components.
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
Enables single particle sensitivity and accurate counting/sizing with reduced component complexity and cost, eliminating the need for air-pumps and filters, and allowing operation in various orientations, while maintaining low power consumption and extended battery life.
Implementation Method 1
a beam of radiation is adapted to illuminate a flow of sample fluid so as to define an optically defined sensing zone within which fluid-borne particles may be detected
Implementation Method 2
a first reflector or refractor means is adapted to direct radiation scattered from the fluid borne particle passing through the beam of radiation in the optically defined sensing zone into the first detector means
Implementation Method 3
a first reflector or refractor means is adapted to direct radiation scattered from the fluid borne particle passing through the beam of radiation in the optically defined sensing zone into the first detector means
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An apparatus for the detection of a fluid-borne particle (10) in an optically defined particle sensing zone, the apparatus comprising: i) a scattering chamber (40); ii) a means for providing a sample of fluid (34), containing the fluid-borne particle, in the form of a flow through the optically defined particle sensing zone;iii) A means for generating a beam of radiation (12) through the optically defined particle sensing zone;iv)a single reflector or refractor (14) means having a primary focus (16) within the optically defined particle sensing zone and a secondary focus (20) located outside the beam of radiation; v) a detector means comprising a first photosensitive detection area (26) a second photosensitive detection area (29); vi) a means for deriving area from the radiation detected by the first photosensitive detection area and second photosensitive detection area of the detection means wherein the single reflector or refractor means is adapted to direct radiation scattered from the fluid borne particle passing through the beam of radation within the optically defined particle sensing zone to the detection means located at the secondary focus of the single reflector or refractor means and the optically sensing zone comprises a first and a second zone.