Concentric Plunger Dispenser Assembly for Consistent Two-Component Epoxy Mixing
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Solution Overview
Problem
Two-component epoxies dispensed using hand-actuated syringe systems often suffer from incorrect mix ratios due to differing viscosities of resin and activator, leading to inconsistent hardening, as the lower viscosity material exits more quickly than the higher viscosity material when the plungers are tilted, reducing the amount of higher viscosity material dispensed.
Innovation Solution
A dispenser assembly with a concentric plunger design and housing structure that maintains a consistent mix ratio of chemical compounds, including a plunger with inner and outer portions and a housing with distinct interior regions for each compound, ensuring equal dispensing even when tilted, utilizing a static mixer assembly for mixing the compounds before dispensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a force is applied to the top surface of the plungers, then the resin and activator flow out of fluid ports, but the lower viscosity material exits more quickly than the higher viscosity material, causing incorrect mix ratio
Solution Approach 1:
The plunger is segmented into first and second distinct plungers that operate independently within separate syringe bodies. Each plunger is sized and shaped to account for the different viscosities of the materials it dispenses, allowing tailored control over the dispensing rate of each component to achieve consistent mix ratios
Solution Approach 2:
The first plunger is specifically sized and shaped to dispense the higher viscosity material at a controlled rate, while the second plunger is sized and shaped differently to dispense the lower viscosity material. This local differentiation in plunger properties compensates for the viscosity differences and maintains correct mix ratios
2Speed
If the plungers are tilted relative to the syringe bodies, then the lower viscosity material exits more quickly, but the amount of higher viscosity material dispensed is reduced
Solution Approach 1:
The segmented plunger design allows each plunger to be optimized for its specific material's viscosity and flow characteristics, enabling independent control of dispensing rates even when tilted, thereby maintaining the correct quantity relationship between the two materials
3Reliability
If the mix ratio of resin to activator is incorrect, then the mixed materials do not harden properly, but adjusting the dispensing rates reduces productivity
Solution Approach 1:
The plungers are pre-sized and pre-shaped during manufacturing to account for the different viscosities of the materials. This preliminary design ensures that under normal actuation, the correct mix ratio is achieved automatically without requiring real-time adjustment or slowing down the dispensing process
Data Source
AI summary
A dispenser assembly having a plunger and a housing is provided. The plunger has an inner plunger portion and an outer plunger portion disposed concentrically around the inner plunger portion. The housing has an inner tubular housing wall, an outer tubular housing wall, and first and second outlet members. The outer tubular housing wall is disposed concentrically around the inner tubular housing wall. The inner tubular housing wall defines a first interior region therein, and the inner tubular housing wall and the outer tubular housing wall define a second interior region therebetween. The first and second outlet members fluidly communicate with the first and second interior regions, respectively. The inner plunger portion is slidably received in the first interior region. The outer plunger portion is slidably received in the second interior region.