pH Electrode Assembly with Spiral Ion Pathway and Seal-Free Sealing
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Solution Overview
Problem
Existing pH meter electrode assemblies face challenges in efficient and reliable assembly due to the use of sealants that require curing, leading to potential gaps and inefficiencies, and lack of positioning mechanisms result in loosening, affecting assembly yield and service life.
Innovation Solution
An electrode assembly design featuring ion barrier units with impermeable substrates and permeable transport rings, along with electrolyte retaining units, forms a spirally winding pathway using dowels and electrolyte impregnated wooden components, eliminating the need for sealants and ensuring tight interconnections for efficient assembly and extended service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sealants are used to bond toroidal plugs and dowels, then fluid sealing between components is achieved, but assembly time increases due to curing requirements and assembly complexity increases
Solution Approach 1:
The patent removes the sealant component entirely from the assembly. Instead of using epoxy resin that requires curing, the design employs mechanical interference fits between precisely machined components (toroidal plugs, dowels, and housing) to achieve both structural bonding and fluid sealing simultaneously, eliminating the time-consuming curing step while maintaining sealing reliability
Solution Approach 2:
The mechanical connection components (dowels and toroidal plugs) are designed to serve dual functions: both structural assembly/bonding and fluid sealing. The interference fit mechanism provides both the mechanical strength to hold components together and the sealing function previously requiring separate sealant material, thereby simplifying the assembly process while maintaining both structural integrity and fluid tightness
2Reliability
If sealants are used to isolate dowels, then fluid isolation between dowels is achieved, but assembly precision requirements increase and assembly complexity increases
Solution Approach 1:
The patent divides the internal assembly into discrete, independently manufacturable components (toroidal plugs, dowels, housing sections) with precisely defined mating surfaces. Each component can be manufactured and inspected separately for dimensional accuracy, then assembled through simple interference fits. This segmentation allows fluid isolation to be achieved through precise mechanical tolerances rather than relying on sealant application quality, actually reducing the skill level required during assembly while maintaining isolation reliability
Solution Approach 2:
The sealant material is completely removed from the design. Fluid isolation between dowels and components is achieved exclusively through mechanical interference fits and precise tolerancing of mating surfaces. This eliminates the need for operators to skillfully apply and position sealant, reducing assembly complexity and precision requirements during the assembly process while maintaining reliable fluid isolation through engineered mechanical clearances and interference fits
3Reliability
If dowels are inserted into aligned side apertures, then ion transfer pathway is formed, but ion loss increases and service life decreases
Solution Approach 1:
The patent introduces asymmetry in the positioning of side apertures across successive toroidal plugs. Instead of aligning apertures in a straight line, each successive plug has its side apertures offset at different angular positions around the central axis. This creates a spiraling ion transfer pathway through the electrolyte-saturated dowels, significantly increasing the path length and reducing ion loss while maintaining effective ion transfer for pH measurement
Solution Approach 2:
The offset arrangement of side apertures in successive toroidal plugs creates a curved or spiraling ion transfer pathway rather than a straight line. Ions must traverse a longer, winding path through the dowels and electrolyte, increasing the distance impurities must travel to reach the reference electrode and reducing the rate of ion loss and electrode poisoning, thereby extending service life while maintaining measurement reliability
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 design provides a reliable and efficient assembly process with a spirally winding pathway that reduces ion loss and impurity fouling, extending the electrode's service life and ensuring accurate measurements by filtering impurities and delaying electrode poisoning.
Implementation Method 1
The transport ring is made of a liquid permeable material, and a transport speed of the transport ring for ions along a transverse plane, which is perpendicular to the central axis, is greater than a transport speed of the transport ring for the ions along the direction parallel to the central axis
Implementation Method 2
The plurality of dowels 21 are provided for an interconnection and a fluid communication between two adjacent ones of the toroidal plugs 20. The plurality of sealants 30 are respectively coated on interior transverse surfaces of the plurality of toroidal plugs 20 and the plurality of dowels 21 to form fluid type seals between the two adjacent ones of the toroidal plugs 20 and two adjacent ones of the dowels 21. Each of the toroidal plugs 20 has two side apertures 200 penetrating therethrough along the direction parallel to the central axis (Z) for insertion of the dowels 21 and/or filling with the sealant 30. To be specific, in each of the toroidal plugs 20, at least one of the side apertures 200 is penetrated by one of the dowels 21. By virtue of the characteristic of the dowels 21 having fiber pores so as to be impregnated in the electrolyte, such dowels 21 are capable of retaining the conductive ions and cooperate with the toroidal plugs 20 to form an electrical pathway for transferring hydrogen ions of the sample fluid
Data Source
AI summary
An electrode assembly of a pH meter includes a plurality of ion barrier units and electrolyte retaining units that are arranged along a central axis. Each ion barrier unit includes an impermeable substrate, a transport ring, and an impermeable cover. The substrate has a receiving cavity, and a first side aperture with a first dowel inserted therein. The transport ring is disposed within the receiving cavity and is liquid permeable. The cover is disposed over and seals an opening of the receiving cavity, and has a second side aperture penetrating the cover, and a second dowel inserted into the second side aperture. The electrolyte retaining units are each disposed between two successive ion barrier units and are permeable. A sensing electrode penetrates through the ion barrier units and the electrolyte retaining units along the central axis.