Pipe Joint Sealing Material with Dual Bulb Design
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Solution Overview
Problem
Existing pipe joints require a large insertion force due to the deformation of the bulb part during spigot insertion, and they lack efficient sealing material attachment and detachment prevention mechanisms, especially when pipes have bent axes or require corrosion protection.
Innovation Solution
The pipe joint design incorporates a sealing material with a first and second bulb, a narrow part, and a push ring to reduce insertion force, ensure uniform sealing, and maintain sealing properties even with axial movement, while also using a centering member and anticorrosive coatings to prevent corrosion and misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bulb part is designed to be compressed between the socket and spigot to generate sealing pressure, then sealing properties are improved, but a large insertion force is required to deform the bulb part outward during spigot insertion
Solution Approach 1:
The sealing material is divided into a heel part and a bulb part with distinct functions. The heel part is held by the socket and provides structural support, while the bulb part is compressed to generate sealing pressure. This segmentation allows the bulb part to be designed for compression rather than bending, reducing insertion force while maintaining sealing effectiveness.
Solution Approach 2:
Instead of designing the bulb part to bend outward during insertion (as in conventional designs), the invention inverts the approach by designing it to be compressed inward between the socket and spigot. This inversion changes the deformation mode from bending to compression, significantly reducing the required insertion force while achieving reliable sealing.
2Reliability
If a lock ring is used to prevent detachment between socket and spigot, then detachment prevention function is achieved, but the structure becomes more complex and requires additional components
Solution Approach 1:
The detachment prevention function is merged with the sealing material itself. The bulb part of the sealing material is designed to engage with the spigot's outer peripheral surface, providing both sealing and detachment prevention in a single integrated component rather than requiring separate lock rings or retaining mechanisms.
Solution Approach 2:
The sealing material is given multiple functions: it provides sealing pressure through compression, prevents detachment through engagement with the spigot, and maintains structural integrity through its heel part held by the socket. This multi-functionality eliminates the need for additional specialized components, simplifying the overall structure.
3Reliability
If the inner diameter of the bulb part is reduced towards the socket inner side to create an elliptical cross-section, then sealing surface pressure is generated, but the insertion force required to deform the bulb part increases
Solution Approach 1:
The invention changes the parameter of deformation mode from bending (elliptical cross-section formation) to compression. By designing the bulb part to be compressed uniformly between the socket and spigot rather than bent into an elliptical shape, the sealing surface pressure is generated with significantly lower insertion force while maintaining effective sealing.
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 design achieves reduced insertion force, improved sealing efficiency, reliable detachment prevention, and corrosion protection, allowing for efficient assembly and operation of pipe joints with bent axes and reduced weight and cost.
Implementation Method 1
the bulb part is compressed between the inner circumferential surface of the socket and the outer peripheral surface of the spigot to generate a sealing surface pressure
Implementation Method 2
the inner circumferential portion of the bulb part is bent and deformed (diameter expansion) outward in the pipe diameter direction
Data Source
AI summary
An annular sealing material seals a pipe joint between a socket and a spigot. The sealing material includes a bulb part which is composed of a first bulb, a second bulb located closer to the inner side of the socket than the first bulb, and a narrow part present between the first and second bulbs. The first bulb is pressed against the inner circumferential surface of the socket. The second bulb is pressed against the outer peripheral surface of the spigot. The second bulb is inclined towards the pipe center from the first bulb in a natural state before it is provided between the socket and the spigot. The inner diameter of the second bulb is smaller than the outer diameter of the spigot in the natural state. The second bulb is extensible in the pipe diameter direction due to elastic deformation of the narrow part.