Optical Drop Detector Using High-Frequency Light Pulses
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Solution Overview
Problem
Conventional low-flow meters require frequent recalibration and physical contact with the fluid, making them impractical for long-term use in medical and research applications, especially for measuring slow flow rates of fluids like blood and urine output.
Innovation Solution
An optical drop detection system using high-frequency light pulses with automatic feedback to adjust frequency and intensity, eliminating the need for recalibration and physical contact, by calibrating the system to maintain a predetermined number of light hits per drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional flow meters are used for measuring slow flow rates, then measurement capability is improved, but frequent recalibration and physical contact with fluid are required
Solution Approach 1:
The patent replaces mechanical/electrical contact-based measurement systems with an optical measurement system. Light beams are transmitted through the fluid path and detected by photodetectors, eliminating the need for physical contact between measurement components and the fluid. This substitution of mechanical systems with optical systems resolves the contradiction by maintaining measurement precision while eliminating the need for frequent recalibration and physical contact.
Solution Approach 2:
The patent introduces light beams as an intermediary medium to measure fluid flow. Instead of direct contact between sensors and fluid, the light acts as a mediator that carries information about the fluid's presence and flow characteristics. This intermediary approach allows accurate measurement of slow flow rates without requiring the measurement system to physically interact with the fluid, thereby improving reliability.
2Reliability
If optical system with high frequency light pulses is used, then recalibration is eliminated, but adjustment of frequency and light intensity is required
Solution Approach 1:
The patent implements a self-adjusting optical system where the frequency and intensity of light pulses are automatically optimized based on detected drop characteristics. The system monitors the interaction between light pulses and drops, and self-corrects parameters to maintain optimal measurement conditions. This self-service capability eliminates the need for manual adjustment while maintaining ease of operation, resolving the contradiction between reliability and operational simplicity.
3Measurement precision
If electrodes are used to count droplets, then droplet detection is achieved, but physical contact with fluid requires calibration
Solution Approach 1:
The patent replaces electrode-based electrical contact measurement with optical detection using light beams and photodetectors. This substitution eliminates the need for calibration related to electrical contact characteristics, fluid conductivity variations, and electrode wear. The optical system provides consistent detection accuracy without the calibration requirements inherent in electrical contact methods, resolving the contradiction between detection accuracy and manufacturing simplicity.
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 optical system provides a maintenance-free solution for long-term use, accurately measuring low flow rates without recalibration, ensuring reliable operation and reducing maintenance needs.
Implementation Method 1
at least one optical transmitter which produces a plurality of light beam pulses of microsecond duration and at millisecond intervals, and at least one optical receiver positioned to register receipt of said light pulses transmitted through the path of drops generated by said drop generator
Data Source
AI summary
The invention provides an optical drop detection system (10), for a low-flow metering device of the type having a drop generator 12, 24, (19), the system comprising at least one optical transmitter (26) which produces a plurality of light beam pulses (28) of microsecond duration and at millisecond intervals, and at least one optical receiver (33) positioned to register receipt of the light pulses (28) transmitted through the path of drops (18) generated by the drop generator (12, 24, 19) and to record the number of pulses which hit a given drop and which do not register on the receiver (32), the frequency and strength of the pulses being calibrated so that a single drop is impinged upon by a plurality of pulses, and further comprising automatic feed-back means for adjusting the parameters of interaction between the at least one optical transmitter (26) and the at least one optical receiver (32) to produce and maintain a predetermined minimum and a predetermined maximum number of hits per drop.