Elastomer Insert Sealing Device for Plastic Pipeline Branch Connections
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Solution Overview
Problem
Existing connection devices for plastic pipelines are prone to leaks due to insufficient clamping forces and contact surface area, especially when interacting with transverse openings in plastic pipes, which are not as securely anchored as those in concrete pipes.
Innovation Solution
A connection device featuring a hollow, soft elastomer insert with a conical screw area and a harder fitting that includes a stop bead and a circumferential support rib, providing additional sealing pressure and anchoring within the transverse opening, ensuring secure sealing even in plastic pipes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional connection device with a sealing collar is used in a plastic pipeline, then the connection can be made, but the sealing reliability is insufficient due to reduced contact surface area and clamping forces compared to concrete pipes
Solution Approach 1:
The sealing function is divided into two distinct sealing elements: the elastomer insert provides sealing at the inner edge of the transverse opening, while the sealing collar provides sealing at the outer edge. This segmentation allows each sealing element to be optimized for its specific location and function, ensuring reliable sealing even in thin-walled plastic pipes where the total contact surface area is limited.
Solution Approach 2:
The connection device combines two different materials with complementary properties: a soft elastomer insert that can deform to seal against the inner edge, and a harder sealing collar that maintains structural integrity and provides external sealing. This composite approach allows the device to adapt to the thinner wall thickness of plastic pipes while maintaining adequate sealing contact area and clamping forces.
2Reliability
If the elastomer insert is made softer to improve sealing, then sealing effectiveness increases, but the insert may be pushed out by internal pressure in the main line
Solution Approach 1:
The sealing collar acts as an intermediary element between the elastomer insert and the external environment. It provides mechanical support and restraint to the soft elastomer insert, preventing it from being pushed out by internal pressure while allowing the insert to maintain its sealing effectiveness against the inner edge of the transverse opening.
Solution Approach 2:
Different parts of the connection device have different material properties optimized for their specific functions: the elastomer insert is soft and compliant to conform to and seal against the inner edge, while the sealing collar is harder and more rigid to resist internal pressure and maintain structural stability. This local differentiation of material quality resolves the contradiction between sealing effectiveness and pressure resistance.
3Ease of manufacture
If a sealing flange is pulled against the inner edge by an external thread, then connection can be made, but precise machining of the inner edge is required and the seal is sensitive to pipe deformation
Solution Approach 1:
The elastomer insert changes its physical parameters (shape, volume, density) during installation through compression and deformation. This allows it to adapt to variations in the inner edge geometry and pipe deformation, eliminating the need for precise machining while maintaining effective sealing. The material's viscoelastic properties enable it to conform to imperfect surfaces that would prevent sealing with rigid flanges.
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 device achieves enhanced sealing security and reliability across various pipe thicknesses by increasing the sealing surface area ratio and utilizing conical threads to distribute force effectively, preventing leaks under deformation and internal pressure.
Implementation Method 1
As a result of the conicity of the thread area, there is a force component on the connecting piece in the direction out of the transverse opening, which leads to a force acting on the elastomer insert in precisely this outward direction.
Implementation Method 2
The relatively soft bead tends to yield, but this is prevented by the engagement end of the relatively harder connecting piece.
Data Source
Figure 1~3
Figure 4~5
AI summary
The invention relates to a connecting device for a branch pipeline in combination with a transverse opening (40) in a main line, in a manhole or in a wall (4), comprising a hollow-plug-shaped, relatively soft elastomer insert (2), the outer side (20) of which is adapted to the transverse opening and the inner side (23) of which has a conical screwing region (25), and a relatively harder connecting piece which has an engagement end (12), a conical centre part (13) with external thread (15) and a drive end (14). The object of the invention is to design such a connecting device in such a way that it is also suitable for main pipelines or manholes made of plastic and at the same time provides an especially sound seal. According to the invention, the elastomer insert, with respect to the transverse opening, has an inner end with a top bead (21) which, when the connecting device is fitted, bears against the inner margin of the transverse opening, and the engagement end of the connecting piece, when the connecting device is fitted, bears in a supporting manner against the inner end of the elastomer insert, wherein the connecting piece presses the elastomer insert against the inner surface of the transverse opening, and the stop bead is pulled and pressed against the inner margin of the transverse opening.