Aerosol Valve Cup Stiffening via Annular Fold and Grommet
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Solution Overview
Problem
Aerosol valves for dispensing moisture-reactive compositions like polyurethane foams face challenges in reducing production costs while maintaining stability and reliability, particularly in reducing cup thickness and ensuring tightness to prevent moisture ingress and leakage, with existing solutions being either costly or material-intensive.
Innovation Solution
A valve design featuring a thin, planar cup with an annular fold and a grommet that mates with the cup's geometry, allowing for a stiffened structure using lower-grade materials and reducing compressive stress on the grommet, along with a valve stem that slips on the grommet flange to reduce material usage and enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cup thickness is reduced to lower production costs, then manufacturing cost decreases, but mechanical strength and tightness deteriorate
Solution Approach 1:
The cup is constructed using composite material structure combining thin metal plate with integrated annular fold reinforcement. The fold creates a ribbed structure that composite the thin plate with geometric reinforcement, achieving high strength-to-weight ratio and allowing thin cup walls while maintaining mechanical strength and tightness.
Solution Approach 2:
The annular fold in the cup creates a curved ribbed structure that provides mechanical reinforcement. The curved geometry of the fold distributes stress more effectively than flat structures, enabling the use of thinner cup materials while maintaining adequate mechanical strength and sealing capability.
2Reliability
If grommet compressive stress is reduced to improve reliability, then sealing reliability improves, but cup structural strength deteriorates
Solution Approach 1:
The cup structure is segmented into distinct functional zones: the thin planar cup wall for containment, the annular fold for structural reinforcement and grommet positioning, and the peripheral bead for sealing. This segmentation allows the cup to provide structural support through the fold while maintaining thin walls, reducing compressive stress on the grommet without sacrificing overall cup strength.
Solution Approach 2:
The annular fold adds a third dimensional element to the otherwise thin two-dimensional cup structure. This folded rib creates a three-dimensional reinforcement structure that provides mechanical strength and positioning functionality, allowing the cup to maintain structural integrity with reduced wall thickness and lower grommet compressive stress.
3Loss of substance
If cup thickness is reduced to prevent moisture ingress, then material usage decreases, but tightness and sealing capability worsen
Solution Approach 1:
The thin cup is reinforced with an annular fold creating a composite structure that combines thin material with geometric reinforcement. This allows significant material reduction compared to solid thick-walled cups while maintaining sealing capability through the fold structure and its interaction with the grommet.
Solution Approach 2:
The cup is segmented into functional zones with the annular fold creating a dedicated sealing and reinforcement zone. This segmentation allows the thin cup body to be separated from the sealing function, which is handled by the fold-grommet interface, enabling material reduction without compromising tightness.
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 cost savings by using thinner materials and less expensive production processes while maintaining the reliability and stability of the valve, preventing moisture ingress, and allowing for efficient dispensing of polyurethane foams under pressure.
Implementation Method 1
The grommet is roughly a hollow cylindrical tube which central bore opens at both ends and which comprises at its end located below the cup a substantially annular flange radially extending outwards and which upper surface contacts the lower (inner) surface of the cup and is suitable for sealing against the latter
Implementation Method 2
Since the can is pressurized, the content of the can is dispensed through the valve
Data Source
AI summary
A valve for dispensing moisture reactive liquids is disclosed. The valve has a valve cup for tightly closing a container including a through opening, and a first annular fold forming a groove in a first, inner surface and a rib in a second, outer surface. The valve includes a resilient grommet and a valve stem. The valve stem includes a hollow tubular portion, defining a central bore snugly fitting in the grommet central bore and extending on both sides of the grommet with a first end opening to ambient and a second, opposite end being closed by a circular end base greater than the diameter of the bore of the grommet. The upper surface of the flange portion of the grommet mates with the first, inner surface of the cup including the portion of the grommet mating the groove formed by the fold.