Mass-Based Micro Flow Measurement with Porous Packing
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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, packing assembly with low water absorption and gas permeability, and a capillary receiving tube in an L shape with specific alignment and structure to minimize evaporation and stabilize liquid flow for accurate weighing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the needle is submerged in the liquid surface, then the accumulation of liquid in the needle is eliminated, but liquid discharging pressure and surface tension constantly change as the liquid surface rises, resulting in measuring error
Solution Approach 1:
The patent introduces an intermediary substance (oil film or porous material) between the liquid and the measurement system. The oil film layer or porous material acts as a mediator that maintains stable surface tension while allowing liquid to pass through, thereby resolving the contradiction between eliminating liquid accumulation and maintaining stable surface tension properties.
Solution Approach 2:
The patent employs porous materials (such as porous plates or porous cups) that allow liquid to pass through while maintaining stable surface tension. The porous structure provides capillary action to control liquid flow while the material itself maintains consistent surface tension properties, solving the measurement stability issue.
2Stability of the object's composition
If the liquid surface is covered with the oil film, then surface tension stability is improved, but the measuring error increases due to additional force from surface tension
Solution Approach 1:
The patent applies local quality by using porous materials with specific pore size and distribution that are optimized for the measurement purpose. The porous structure provides localized capillary action only where needed, maintaining surface tension stability in the bulk liquid while allowing controlled liquid passage through the porous material, thereby reducing measurement error.
Solution Approach 2:
The patent changes the physical parameters of the system by using porous materials with specific pore sizes and surface properties. This parameter change allows the system to maintain stable surface tension while reducing the additional force from surface tension that causes measurement error, as the porous structure provides alternative liquid passage mechanisms.
3Stability of the object's composition
If the needle is suspended vertically on a capillary tube, then liquid surface height is maintained constant, but slight flow changes cause liquid column shape changes that alter additional force, resulting in error
Solution Approach 1:
The patent introduces porous material as an intermediary between the liquid column and the measurement system. This intermediary provides a more stable interface that is less sensitive to small flow changes, maintaining constant liquid surface height while reducing the impact of liquid column shape changes on the measurement force.
Solution Approach 2:
The patent uses porous materials that provide stable capillary action and maintain constant liquid surface height while being less sensitive to flow variations. The porous structure distributes liquid flow more evenly, preventing the formation of variable liquid column shapes that would alter measurement force.
4Loss of time
If liquid droplets naturally drip into the container, 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 patent implements continuous liquid passage through the porous material, eliminating the intermittent dripping process. This continuous action provides consistent reading time for the weighing balance while the porous structure ensures uniform liquid distribution, preventing nonlinear evaporation and inconsistent residual liquid that cause measurement errors.
Solution Approach 2:
The patent employs porous materials that provide continuous, uniform liquid passage through capillary action. This continuous flow mechanism ensures consistent reading time while the porous structure prevents droplet formation and impact, eliminating the measurement errors associated with nonlinear evaporation and inconsistent residual liquid.
5Object-affected harmful factors
If the liquid surface in the open-type collecting container is not covered with the oil film, then evaporation is reduced, but large amount of evaporation is generated affecting measuring result
Solution Approach 1:
The patent uses porous materials that provide a barrier to evaporation while allowing liquid to pass through. The porous structure acts as a physical barrier that reduces evaporation loss from the liquid surface, thereby improving measurement precision without blocking liquid flow.
Solution Approach 2:
The patent employs thin film or membrane structures (porous materials) that act as barriers to evaporation. These thin films allow liquid passage through capillary action while blocking vapor escape, thereby reducing evaporation loss and improving 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 reduces measuring errors by stabilizing liquid flow and minimizing evaporation, providing improved precision and repeatability in micro flow measurements.
Implementation Method 1
the capillary receiving tube is disposed in an L shape, 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
Implementation Method 2
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
Implementation Method 3
the packing assembly is made of a material with low water absorption and can be gas-permeable
Implementation Method 4
an inner anti-evaporation cover; an outer anti-evaporation assembly, where the outer anti-evaporation assembly covers the inner anti-evaporation cover
Implementation Method 5
a weighing balance, disposed in the inner anti-evaporation cover; a liquid collecting container, disposed in the inner anti-evaporation cover and placed on the weighing balance
Data Source
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.