Dispensing Pump Polymer Spring Recyclability
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Solution Overview
Problem
The presence of metal springs in dispensing pumps hinders the recycling process due to the need to separate them from plastic components, making it difficult to recycle the entire system effectively.
Innovation Solution
A dispensing pump with a polymer compression spring assembly, featuring a slotted tubular spring element and loading cones made from tensile polymer materials, which allows for radial expansion and contraction, enabling the entire assembly to be molded from a single plastic material, facilitating easy recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal spring is used in the dispensing pump, then the spring provides reliable elastic force for pump operation, but the metal spring hinders recycling due to separation requirements from plastic components
Solution Approach 1:
The patent changes the material parameter of the spring from metal to polymer, specifically using a tensile polymer that can be molded into a slot-shaped cross-section. This material substitution maintains the elastic functionality while enabling the spring to be made from recyclable plastic materials, thus resolving the contradiction between reliability and recyclability
Solution Approach 2:
The patent employs composite material design by creating a polymer spring with a slot-shaped cross-section that combines the elastic properties of tensile polymers with the structural integrity needed for pump operation. The slot configuration allows the polymer to exhibit spring-like behavior while being fully compatible with plastic recycling processes
2Ease of manufacture
If a polymer spring is used instead of metal, then recyclability is improved, but the spring material must maintain sufficient elastic properties and durability
Solution Approach 1:
The patent selects specific polymer materials with appropriate tensile properties and elastic recovery characteristics to replace metal springs. The polymer material parameters are optimized to provide sufficient force for pump operation while maintaining durability through repeated compression and extension cycles
Solution Approach 2:
The patent employs curved and rounded geometric features in the polymer spring design, including the slot-shaped cross-section with rounded corners and the overall helical or coil configuration. These curved geometries help distribute stress evenly throughout the polymer structure, preventing stress concentration and enhancing durability
3Ease of manufacture
If the spring is made from tensile polymer material, then the entire pump assembly can be molded from single plastic material for easy recycling, but the material must withstand repeated compression and expansion cycles
Solution Approach 1:
The patent utilizes the viscoelastic properties of tensile polymers, which exhibit both elastic recovery and stress relaxation characteristics. This allows the spring to return to its original shape after compression while dissipating energy through controlled deformation, thereby extending the life cycle under repeated loading conditions
Solution Approach 2:
The patent incorporates strain reducing ribs and rounded transition zones in the polymer spring design that preemptively address stress concentration points. These design features cushion the polymer structure against high-stress regions during compression and expansion, preventing premature fatigue failure and extending operational life
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 all-plastic compression spring assembly enhances recyclability and maintains the functionality of the dispensing pump, ensuring efficient material use and reduced waste, while maintaining the spring's performance and longevity through strain distribution and design features like ribbed structures.
Implementation Method 1
The tubular spring element is disposed coaxially about the piston stem between the first and second loading cones. When the dispensing head is compressed, the loading cones are axially compressible toward each other within the slotted tubular spring element whereby the slotted tubular spring element radially expands in tension to create an opposing radial contraction force, and in turn, an axial extension spring force.
Implementation Method 2
When the dispensing head is compressed, the loading cones are axially compressible toward each other within the slotted tubular spring element whereby the slotted tubular spring element radially expands in tension
Implementation Method 3
When released, the spring element elastically returns to its normal at rest shape, returning the loading cones and dispensing head to their normal at rest positions.
Data Source
AI summary
A dispensing pump (1000) includes a polymer compression spring (1048), base vents (1060) and a flow baffle (1092). The dispensing pump includes a pump base (1002), and a dispensing head (1004) having a piston stem (1034). The polymer compression spring assembly includes a slotted tubular spring element (1048) and first and second loading cones received at opposing ends of the slotted tubular spring element. The venting ports allow air to escape when capping the container after filling and the flow baffle reduces or prevents the product from being pulled into the pump accumulator before residual air (headspace) has been evacuated from the container during the initial priming strokes.