Annular Seal Spring Mechanism for Polymer Filtration Leakage
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Solution Overview
Problem
Existing filtration apparatus in plasticating resin extrusion or injection molding suffer from leakage and degradation due to gaps in sealing devices, particularly under high pressures and temperatures with low viscosity molten materials, leading to maintenance issues and reduced quality of processed polymer.
Innovation Solution
A filtration apparatus with a sealing device featuring an annular seal and a primary spring with overlapping tangs or multiple springs in overlapping contact, eliminating gaps and creating a continuous barrier to prevent polymer melt migration, ensuring effective sealing against radial forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a C-shaped spring sealing device is used in filtration apparatus, then the sealing device can provide spring pressure to maintain seal contact, but the gap between the spring ends allows molten material to migrate and contact the seal, causing degradation and failure
Solution Approach 1:
The patent converts the harmful effect of molten material contact into a beneficial sealing mechanism. The controlled gap in the C-shaped spring allows the molten material to contact the spring ends, creating radial inward forces that compress the seal against the slide plate, transforming the harmful migration into a useful sealing force.
Solution Approach 2:
The patent changes the physical state and force parameters of the spring under operating conditions. As molten material contacts the spring ends, the spring compresses and transforms axial forces into radial sealing forces, dynamically adjusting the sealing pressure based on the process conditions.
2Reliability
If the sealing device must prevent leakage under high pressure and temperature with low viscosity materials, then sealing effectiveness improves, but the sliding plate mobility between filter assemblies is restricted
Solution Approach 1:
The patent utilizes parameter changes in the spring's mechanical properties. The spring is designed with specific material and geometric parameters that allow it to provide adequate sealing force under high pressure while maintaining sufficient elasticity to permit sliding plate movement during filter assembly interchange.
Solution Approach 2:
The sealing device is designed to be dynamic rather than static. The spring continuously adjusts its compression force in response to changing operating conditions, providing just enough sealing pressure to prevent leakage while allowing the necessary mechanical movement for filter assembly replacement.
3Stress or pressure
If the spring is designed to resist radial forces from high pressure polymer melt, then sealing pressure is maintained, but the spring structure becomes more complex and prone to material contact
Solution Approach 1:
The spring is segmented into a C-shaped configuration with distinct functional zones: the open ends that contact molten material to generate radial forces, the body that provides structural integrity, and the region that contacts the seal to transmit sealing pressure. This segmentation allows each part to perform its specific function efficiently.
Solution Approach 2:
The C-shaped spring utilizes curvature to transform forces. The arc shape allows axial compression forces from the molten material to be converted into radial inward forces that press the seal against the slide plate, providing an elegant geometric solution to the force transformation problem.
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 solution provides a low-maintenance, low-wear sealing system that effectively prevents leakage and maintains the quality and uniformity of molten polymer materials by eliminating pathways for polymer melt flow, even under high pressures and temperatures.
Implementation Method 1
The spring is angled relative to and contacts the thrust surface of the annular seal for biasing the sealing surface of the seal against the slide plate
Implementation Method 2
as pressure of the polymer melt in the bore increases, radial forces are exerted on the spring which transfers against the thrust surface of the seal causing the annular seal to be biased against the slide plate
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
A polymer filtration apparatus for sealing a slide plate translatable across a bore of an extrusion or mold machine, includes an annular seal having a sealing surface biased against the slide plate by a spring mechanism. The annular seal has a thrust surface angled relative to the sealing surface. The thrust surface is located at an opposite axial end of the annular seal from the sealing surface. The spring mechanism can be a single spring with overlapping tangs or a multiple spring assembly in overlapping relationship, with or without tangs, to form a continuous barrier. The spring assembly exerts a radial force against the thrust surface of the annular seal to bias the seal in an axial direction against the downstream slide plate. In operation, pressurized polymer melt in the extrusion bore further biases the spring against the annular seal, which is transferred to the seal and the slide plate.