Dual Polymer Metering Rods for Foam Dispensing
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Solution Overview
Problem
Conventional two-component polyurethane foam dispensing guns face issues with uneven dispensing and incomplete shutoff due to varying viscosities and ratios of components, leading to operator errors and increased costs, and lack of cleaning mechanisms, resulting in clogged nozzles and inefficient manufacturing processes.
Innovation Solution
A two-component dispensing gun design featuring interconnected metering rods fabricated from acetal thermoplastic via injection molding, which ensures uniform dispensing and eliminates micro grooves, reducing leakage and the need for presetting, and incorporates a single spring for consistent ratio adjustment, along with a nozzle design that minimizes turbulent flow and cross-over risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional two-component dispensing guns use separate metering rods for each component, then the gun can dispense both components, but uneven dispensing occurs due to varying viscosities and ratios of components
Solution Approach 1:
The patent combines two separate metering rods into a single integrated metering rod structure that meters both components simultaneously. This unified structure ensures that both components are dispensed at consistent ratios without the variability that occurs when using separate adjustable metering rods, directly resolving the uneven dispensing issue caused by varying viscosities and ratios.
Solution Approach 2:
The patent changes the metering mechanism from separate adjustable rods to a single fixed-ratio metering rod with optimized geometry. By altering the structural parameters of the metering system rather than relying on operator adjustment, the design achieves consistent dispensing ratios despite variations in component viscosities.
2Ease of manufacture
If conventional dispensing guns use metallic metering rods with turning or grinding techniques, then the rods can be fabricated, but radial micro grooves are created causing wear and leakage
Solution Approach 1:
The patent replaces traditional metallic metering rods fabricated by turning or grinding with an elastomeric metering rod fabricated by injection molding. This substitution eliminates the mechanical processes that create radial micro grooves, thereby preventing the wear and leakage problems associated with grooved surfaces while simplifying the manufacturing process.
Solution Approach 2:
The patent uses elastomeric material for the metering rod instead of metal, creating a composite solution that combines the benefits of flexible sealing surfaces with resistance to chemical degradation. This material choice eliminates micro groove formation while maintaining manufacturing efficiency through injection molding.
3Reliability
If conventional dispensing guns use presetting techniques to secure mating surfaces, then connection security is improved, but manufacturing time increases due to lengthy hold time requirements
Solution Approach 1:
The patent replaces metallic metering rods requiring presetting with elastomeric metering rods that achieve secure connections through material elasticity and friction. This substitution eliminates the need for lengthy presetting hold times while maintaining reliable connections, thereby increasing manufacturing productivity without compromising connection security.
4Device complexity
If conventional dispensing guns lack cleaning mechanisms, then the gun structure is simpler, but nozzles become clogged and manufacturing efficiency decreases
Solution Approach 1:
The patent employs disposable nozzles that are replaced rather than cleaned, eliminating the need for complex cleaning mechanisms. This approach maintains simple gun structure while preventing clogging issues and maintaining manufacturing efficiency through regular replacement of consumable components.
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 achieves consistent and uniform dispensing of polyurethane foam, reduces manufacturing time and costs, and prevents clogging by ensuring secure mating surfaces and eliminating micro grooves, while maintaining ergonomic benefits and improved performance.
Implementation Method 1
The elastomeric metering rod is friction fit within the dispensing passage
Implementation Method 2
The elastomeric metering rod conforms to the dispensing passage and valve seat
Implementation Method 3
a spring positioned at the rearward end of the dispensing passage and bearing against the rearward end of the elastomeric metering rod to push the elastomeric metering rod forward toward the valve seat
Implementation Method 4
fabricated from an acetal thermoplastic utilizing an injection molding technique
Data Source
AI summary
A metering component for a two-component dispensing gun includes a first metering rod and a second metering rod. The first metering rod includes a first tip section at one end that terminates into a first intermediate sealing section. The first intermediate sealing section terminates at a first base section at an opposite end of the first tip section. The second metering rod includes a second tip section at one end terminating in a second intermediate sealing section, wherein the second intermediate sealing section terminates at a second base section at an opposite end of the second tip section. The first metering rod is interconnected to the second metering rod at the first base section and the second base section.