EPDM Diaphragm Pumping System for Precise Caustic Soda Metering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for treating drinking water with caustic soda lack precision in metering the delivery of sodium hydroxide, leading to potential corrosion issues and metal contamination, as they struggle with handling concentrated solutions and viscosity variations.
Innovation Solution
A diaphragm pumping system with a two-part assembly, featuring a fully-vulcanized ethylene propylene diene monomer (EPDM) rubber diaphragm overmolded onto a rigid insert, capable of tolerating high NaOH concentrations, is used to accurately deliver a precise volume of sodium hydroxide solution into drinking water, mitigating viscosity-based variations and ensuring durability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional metering pumps are used to deliver concentrated NaOH solution, then the pump can operate, but the delivery precision deteriorates due to viscosity variations and chemical corrosion
Solution Approach 1:
The patent changes the material parameter of the diaphragm from conventional elastomers to chemically resistant polymers (PTFE, PVDF, PP) that can withstand high NaOH concentrations. This parameter change prevents chemical degradation and maintains delivery precision across varying solution viscosities and concentrations.
Solution Approach 2:
The patent employs composite construction by overmolding chemically resistant polymer material onto a reinforced insert structure. This composite diaphragm combines the chemical inertness of polymers with the mechanical strength of the insert, enabling reliable operation with concentrated NaOH solutions while maintaining precise volumetric delivery.
2Duration of action of stationary object
If the diaphragm material is made more chemically resistant to tolerate high NaOH concentrations, then the durability improves, but the flexibility and responsiveness may deteriorate
Solution Approach 1:
The patent uses a composite structure where chemically resistant polymer (PTFE, PVDF, or PP) is overmolded onto a reinforced insert. The polymer provides chemical resistance and durability in high NaOH environments, while the reinforced insert maintains structural integrity and responds effectively to actuation forces, preserving diaphragm flexibility and operational responsiveness.
Solution Approach 2:
The patent applies different material properties to different parts of the diaphragm assembly: the polymer coating provides chemical resistance where needed, while the reinforced insert provides mechanical response where needed. This local differentiation of material qualities allows the diaphragm to simultaneously achieve durability and flexibility.
3Strength
If a reinforced insert structure is added to the diaphragm assembly, then the mechanical strength and durability improve, but the device complexity increases
Solution Approach 1:
The patent integrates the reinforced insert and polymer diaphragm into a single overmolded composite component. This integration, while adding manufacturing complexity, reduces assembly complexity by eliminating separate parts and joints. The monolithic composite structure provides enhanced mechanical strength while maintaining relatively simple installation as a single unit.
Data Source
AI summary
Described is a method for treating water with sodium hydroxide. The method can increase the accuracy of the volume of a stock sodium hydroxide solution that is delivered to the water being treated. The method can include pumping a concentrated aqueous sodium hydroxide stock solution with a diaphragm pumping system that has a two-part diaphragm assembly with a polymeric diaphragm overmolded onto a rigid insert. The polymeric diaphragm can be made of a fully-vulcanized ethylene propylene diene monomer rubber that is injection molded over the rigid insert.