Composite Pipe Gasket With Gripping Segments for PVC-O Joint Restraint
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Solution Overview
Problem
Molecularly oriented plastic pipes, such as PVC-O pipes, pose challenges in providing a securely sealed and restrained joint due to their unique geometry and properties, particularly the 'Anger Raceway' design, which complicates the integration of effective sealing and restraint systems.
Innovation Solution
A sealing and restraint system featuring an annular gasket with arcuate rigid gripping segments made of resilient elastomeric material and metal, designed to fit within the 'Anger Raceway', providing a secure seal and restraint by engaging the male pipe's exterior surface with gripping teeth and a positive stop mechanism, allowing for easy assembly and resistance to separation forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a homogeneous rubber gasket is used, then the gasket can be easily deformed and inserted by hand, but it cannot provide sufficient restraint against separation forces
Solution Approach 1:
The gasket is constructed as a composite structure combining a resilient elastomeric material body with rigid gripping segments (metal or rigid plastic) embedded within it. This composite design allows the elastomeric portion to provide flexibility for hand insertion while the rigid segments provide mechanical restraint against separation forces, resolving the contradiction between ease of operation and joint reliability.
2Reliability
If a rigid material is used for the gasket body, then the gasket can provide restraint, but it cannot be easily deformed and inserted by hand
Solution Approach 1:
The gasket combines rigid gripping segments for restraint with a flexible elastomeric matrix that allows the entire assembly to be deformed and inserted by hand. The rigid segments are embedded within the elastomeric material, which provides the necessary flexibility during installation while the rigid segments maintain their restraint function, resolving the contradiction between reliability and ease of operation.
Solution Approach 2:
Different regions of the gasket have different material properties: the gripping segments are rigid to provide restraint, while the elastomeric body is flexible to allow insertion. This local differentiation of material properties allows each region to perform its specific function optimally, resolving the contradiction between rigidity for restraint and flexibility for insertion.
3Reliability
If an external mechanical restraint system is used, then joint restraint is provided, but the system becomes complex and requires additional components
Solution Approach 1:
The restraint function is merged with the sealing gasket itself by embedding rigid gripping segments within the elastomeric gasket body. This integration eliminates the need for separate external mechanical restraint systems, reducing overall system complexity while maintaining the joint restraint function. The gasket simultaneously provides both sealing and restraint functions.
Solution Approach 2:
The gasket is designed to perform multiple functions: sealing the joint and providing mechanical restraint against separation forces. By embedding rigid gripping segments within the elastomeric body, the single gasket component achieves both sealing and restraint functions that would otherwise require separate components, reducing system complexity.
4Ease of operation
If the gasket is made flexible for insertion, then it can be installed easily, but it may extrude under pressure
Solution Approach 1:
The gasket uses a composite structure where the elastomeric material provides flexibility for installation while the embedded rigid gripping segments provide resistance to extrusion under pressure. The rigid segments act as structural reinforcements within the flexible matrix, allowing the gasket to be easily installed while maintaining strength against pressure-induced extrusion.
Solution Approach 2:
The gasket has different material properties in different regions: the elastomeric body is flexible to allow installation, while the embedded rigid segments provide local reinforcement to resist extrusion under pressure. This local differentiation allows the gasket to be both easily installed and resistant to pressure, resolving the contradiction between ease of installation and strength.
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 system effectively seals and restrains PVC-O pipe joints under various pressures, ensuring joint integrity without external mechanical restraints, and can be easily installed by hand, addressing the limitations of traditional systems.
Implementation Method 1
an annular gasket body made of a resilient elastomeric material... capable of both sealing and restraining the female plastic pipe to a mating male pipe
Implementation Method 2
the inner surface of each segment has at least one row of gripping teeth capable of engaging selected points on the exterior surface of the mating male pipe and apply a gripping force
Data Source
Figure 1
Figure 2~2A
Figure 3
AI summary
A pipe joining system and pipe joint are shown in which two sections of plastic pipe, particularly molecularly oriented pipe, are joined, A ring-shaped elastomeric body is installed within a mating groove provided in a mouth region of female pipe section. The ring-shaped body is formed of an injection molded elastomeric material which Is joined to a series of arcuate gripping segments which have teeth on an inner surface thereof which are designed to engage an outer surface of a mating male pipe section to restrain movement of the male pipe after assembly of a pipe joint The gripping segments are separated by a gap which Is open prior to assembly, but which closes during assembly. Each of the segments also has a positive stop feature to prevent over travel of the male pipe section relative to the female pipe section.