Capillary Micro Flow Measurement With Anti-Evaporation Isolation
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Solution Overview
Problem
Existing micro flow measuring technologies using the mass method suffer from significant measuring errors due to evaporation, surface tension changes, and inconsistent liquid droplet formation, leading to unstable readings and inaccurate flow measurements.
Innovation Solution
A micro flow measuring device and method that incorporates an inner anti-evaporation cover, outer anti-evaporation assembly, a weighing balance, a liquid collecting container with a packing assembly made of low water absorption and gas-permeable material, a capillary receiving tube in an L shape, and a liquid outlet tube aligned to allow controlled liquid suction and drip intervals, reducing evaporation and stabilizing readings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the needle is submerged in the liquid surface, then liquid accumulation in the needle is eliminated, but additional force from surface tension constantly changes as liquid is injected, resulting in measuring error
Solution Approach 1:
The patent introduces a capillary tube as an intermediary component between the liquid surface and the weighing balance. The capillary tube allows liquid to drain freely while isolating the weighing balance from direct contact with the liquid surface, thereby eliminating surface tension forces from acting on the balance. This mediator resolves the contradiction by enabling both stable readings and accurate measurement.
Solution Approach 2:
The system is segmented into distinct functional zones: the liquid collection area, the capillary drainage path, and the weighing balance area. By separating the weighing balance from direct liquid contact while maintaining liquid flow measurement capability through the capillary tube, the system achieves both reading stability and measurement precision simultaneously.
2Object-affected harmful factors
If the liquid surface is covered with the oil film, then evaporation is reduced, but the measuring error further increases
Solution Approach 1:
The capillary tube acts as an intermediary that allows the liquid surface to be covered with an oil film for evaporation prevention, while simultaneously preventing the oil film and surface tension forces from directly affecting the weighing balance. This enables the beneficial effect of evaporation reduction without the harmful effect on measurement accuracy.
3Loss of time
If the needle is placed on the liquid surface to form liquid droplets, then sufficient reading time is given to the weighing balance, but nonlinear evaporation, droplet impact, and inconsistent residual liquid result in larger measuring error
Solution Approach 1:
The system uses periodic dripping action through the capillary tube to transfer liquid from the collection container to the weighing balance. This periodic action provides sufficient time for stable readings between drops while maintaining consistent droplet formation through the capillary's uniform dimensions, eliminating the inconsistencies of free droplet formation.
4Stability of the object's composition
If a liquid column is formed to maintain constant liquid surface height, then the influence of liquid surface height change on surface tension is avoided, but the liquid column creates force between the needle and the container that changes with flow, resulting in error
Solution Approach 1:
The capillary tube serves as an intermediary that eliminates the need for a liquid column to maintain constant surface height. By allowing free drainage through the capillary, the liquid surface height can vary naturally without creating additional forces on the weighing balance, thus achieving both surface height stability and measurement accuracy.
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 device improves measurement precision by minimizing evaporation and ensuring stable, repeatable readings through controlled liquid flow and suction intervals, reducing the influence of external gas flow and surface tension changes, thereby enhancing the accuracy of micro flow measurements.
Implementation Method 1
enable liquid discharged by the liquid outlet to be sucked into the liquid receiving opening at intervals
Data Source
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AI summary
The present invention discloses a micro flow measuring device and method based on a mass method. The measuring device includes: an inner anti-evaporation cover; an outer anti-evaporation assembly; a weighing balance; a liquid collecting container; a packing assembly, disposed in the liquid collecting container, where the packing assembly is made of a material with low water absorption and can be gas-permeable, and an accommodating cavity configured to accommodate to-be-measured liquid is formed between a lower end of the packing assembly and a bottom portion of the liquid collecting container; a capillary receiving tube, where an upper end and a lower end of the capillary receiving tube are provided with a liquid receiving opening and a liquid discharging opening respectively, the lower end of the capillary receiving tube passes through the packing assembly vertically and extends into the accommodating cavity, and the upper end of the capillary receiving tube passes through the inner anti-evaporation cover and is bent to be horizontal; and a liquid outlet tube, arranged horizontally, where a liquid outlet of the liquid outlet tube is horizontally aligned with and maintains a first distance with the liquid receiving opening after passing through the outer anti-evaporation assembly, to enable liquid discharged by the liquid outlet to be sucked into the liquid receiving opening at intervals.