Spool Valve Dispenser Continuous Gas Purge Prevents Plugging
Solution Overview
Problem
GBA-Free 2k-SPU foam systems are challenging to apply due to higher viscosity and a tendency for dispensers to plug when flow is repeatedly started and stopped, requiring additional triggers for activation and purging.
Innovation Solution
A dispenser design with a spool valve featuring a fourth flow passage that aligns with the gas feed channel in the closed position, allowing continuous gas flow to purge residual reactants and prevent plugging, eliminating the need for a separate purge trigger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GBA-Free 2k-SPU foam systems are used, then the foam can be applied without gaseous blowing agents, but the components have higher viscosity and the dispenser plugs more quickly when flow is repeatedly started and stopped
Solution Approach 1:
The patent implements a fourth flow passage that continuously purges residual reactants from the dispensing channel even when the dispenser is in the closed position. This preliminary action prevents plugging before it occurs, allowing the dispenser to be repeatedly started and stopped without clogging, thus resolving the contradiction between reliability and ease of operation
Solution Approach 2:
The fourth flow passage maintains continuous gas flow through the dispensing channel regardless of whether the dispenser is actively dispensing foam. This continuous purging action ensures that residual reactants are constantly removed, preventing plugging during idle periods and enabling reliable repeated start-stop operation
2Reliability
If a separate purge trigger is added to prevent plugging, then the dispenser can be purged of residual reactants, but the device complexity increases
Solution Approach 1:
The patent merges the purging function with the existing gas feed system by routing pressurized gas through the fourth flow passage that connects to the dispensing channel. This integration eliminates the need for a separate purge trigger or additional purging mechanism, preventing plugging while maintaining simple two-trigger operation for dispensing
Solution Approach 2:
The pressurized gas feed serves multiple functions: it provides motive and mixing force for the A and B components during dispensing, and it continuously purges residual reactants from the dispensing channel through the fourth flow passage. This multi-functionality prevents plugging without requiring additional triggers or complex mechanisms
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
Prevents plugging of the dispenser when not in use and ensures effective purging and dispensing of GBA-Free 2k-SPU foam systems without requiring additional triggers, improving operational efficiency.
Implementation Method 1
A continuous flow of gas through the dispensing channel while in the 'off' position ensures the dispensing channel does not plug between applications
Implementation Method 2
In low pressure systems, which are systems that can be dispensed at pressures lower than 4 MPa, typically lower than 2 MPa, the pressurized gas is useful as a motive and mixing force for the A and B components
Implementation Method 3
simultaneously feeding an isocyanate component (A Component) with a polyol component (B Component) to create a mixture
Data Source
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AI summary
A dispenser (10) comprises a housing (20) defining at least three feed channels (23, 24, 25) and at least one dispensing channel (26), a spool valve (28, 30) with a spool (30) defining at least four flow passages (31, 32, 33, 34), a deformable sealing plug (40) in at least two (23, 24) of the feed channels and in sealing orientation with both the housing (22) and the spool (30), and a nipple (50) in at least the two feed channels (23, 24) of the housing (22) comprising the sealing plugs (40); wherein the spool (30) can reversibly rotate between an open orientation and a closed orientation can dispense two-component foam formulations and purges the dispensing channel when in the off position.