Flexible Annular Cartridge for Bell and Spigot Pipe Joints
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Solution Overview
Problem
Conventional pipe joining methods face challenges with fluid leakage and damage due to earth shifting and settling, as well as increased complexity and cost from using ball and socket joints or flexible expansion joints, which introduce mechanical weaknesses and require additional assembly steps.
Innovation Solution
A flexible annular cartridge with a frustoellipsoidal outer contour, comprising an annular member with pipe gripping members, a flexible annular gasket, and a backup ring, is used to join and seal bell and spigot pipe joints, allowing for deflection and rotation within the socket without separate ball castings, thus preventing joint separation and gasket blowout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a stationary gasket is used in conventional push-on joints, then the joint structure is simple, but the gasket catches on the spigot during insertion resulting in a bad seal
Solution Approach 1:
The gasket is designed to be movable rather than stationary, allowing it to shift and rotate during spigot insertion to avoid catching, while still maintaining an effective seal. The gasket can move axially and rotate to accommodate the insertion process without compromising the seal integrity.
Solution Approach 2:
The gasket is divided into multiple segments or lobes that can independently move and flex during insertion. This segmentation allows the gasket to navigate the insertion process more easily while maintaining sealing contact with the spigot surface.
2Adaptability or versatility
If ball and socket joints are used to accommodate deflection, then the joint can handle earth shifting and settling, but the device complexity and manufacturing cost increase
Solution Approach 1:
The gasket is designed to perform multiple functions: sealing, accommodating deflection, allowing rotation, and preventing joint separation. This multi-functionality eliminates the need for separate ball castings and mechanical restraint devices, simplifying the overall joint structure while maintaining adaptability to earth shifting and settling.
Solution Approach 2:
The sealing and deflection accommodation functions are merged into a single gasket component rather than requiring separate ball and socket mechanisms. The gasket integrates multiple capabilities that would traditionally require separate mechanical components.
3Adaptability or versatility
If flexible expansion joints are used to accommodate large deflections, then the joint can handle earthquake shaking, but additional mechanical joints and restraint devices are required increasing complexity
Solution Approach 1:
The gasket is designed to accommodate large deflections and earthquake shaking through its flexible, multi-lobed structure that can deform and rotate significantly. This eliminates the need for separate flexible expansion joints and mechanical restraint devices, reducing assembly complexity while maintaining earthquake resistance.
Solution Approach 2:
The gasket utilizes flexible material and a multi-lobed shell structure that can deform elastically to accommodate large deflections and earthquake movements. This flexible design replaces rigid mechanical restraint devices and simplifies the overall joint assembly.
4Stability of the object's composition
If tight joint tolerances are used (minimum bell ID and maximum spigot OD), then deflection is reduced, but the installation flexibility and accommodation of earth settling decreases
Solution Approach 1:
The gasket is designed with dynamic movement capabilities, allowing it to shift and rotate during installation to accommodate varying tolerances and earth settling. This dynamic behavior provides installation flexibility while maintaining joint stability through effective sealing and restraint.
Solution Approach 2:
The gasket's physical parameters (shape, position, orientation) can change during installation and service to accommodate earth settling and tolerance variations. This parameter flexibility allows the joint to adapt to different installation conditions while maintaining stability and seal integrity.
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 robust, cost-effective, and simplified method for joining pipes that accommodates deflection and settling, maintaining a secure seal without additional mechanical weaknesses, and allows for integral pipe socket casting, reducing assembly complexity and potential leaks.
Implementation Method 1
a flexible annular gasket having outer and inner surfaces, opposite first and second ends, and a circumferentially extending sealing lip projecting inwardly from the gasket inner surface
Implementation Method 2
a backup ring having a hardness that exceeds the hardness of the gasket, wherein the backup ring engages the gasket at the gasket first end
Implementation Method 3
an annular member having outer and inner surfaces and opposite first and second ends, comprising a plurality of pipe gripping members positioned on the inner surface
Data Source
AI summary
A flexible annular cartridge for joining and sealing a bell and spigot pipe joint, wherein the outer contour of the cartridge is approximately frustoellipsoidal, the cartridge composed of an annular member having outer and inner surfaces and opposite first and second ends, with a plurality of pipe gripping members positioned on the inner surface; a flexible annular gasket having outer and inner surfaces, opposite first and second ends, and a circumferentially extending sealing lip projecting inwardly from the gasket inner surface, in which the annular member first end engages the flexible annular gasket second end; and a backup ring having a hardness that exceeds the hardness of the gasket, in which the backup ring engages the gasket at the gasket first end. Methods are provided for using the cartridge, as well as a pipe joint that contains the cartridge.