Composite Pipe Joint Gasket Locking for Pressure Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sealed and locked assemblies of cast iron pipes face challenges in achieving both effective pressure resistance and economical manufacturing, as the number of locking inserts required is high due to varying manufacturing tolerances, leading to either poor attachment or risk of perforation at maximum clearances.
Innovation Solution
A locking insert design with a stop tooth and hooking teeth that form specific angles and profiles, allowing for a reduced number of inserts while maintaining effective attachment and pressure resistance, by ensuring a relatively low angle of incidence and using a composite sealing gasket with an anchoring heel made of harder material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of locking inserts is increased to improve pressure resistance, then the risk of perforation is reduced, but the manufacturing cost increases
Solution Approach 1:
The patent changes the geometric parameters of the locking insert, specifically the angle of incidence between 30-45 degrees and the hook shape dimensions, to optimize the distribution of forces. This allows achieving the required pressure resistance with fewer inserts by improving the mechanical efficiency of each insert
Solution Approach 2:
The locking insert is made of hardened steel material with specific mechanical properties (tensile strength ≥ 500 MPa, hardness ≥ 45 HRC), creating a composite structure with the elastomeric seal body. This material selection ensures high strength-to-weight ratio and durability while reducing the number of inserts needed
2Reliability
If the angle of incidence of locking inserts is increased to improve attachment to the plain end, then the locking grip is strengthened, but the punching or perforation forces increase requiring more inserts
Solution Approach 1:
The patent optimizes the angle of incidence parameter to a specific range of 30-45 degrees, which balances the attachment grip and punching force. This parameter optimization allows the insert to maintain strong attachment while distributing forces to avoid excessive punching loads that would require additional inserts
Solution Approach 2:
The locking insert features a curved hook shape with rounded transitions instead of sharp angles. This curvature distributes the contact forces more evenly across the plain end surface, reducing stress concentrations and punching forces while maintaining attachment effectiveness
3Ease of manufacture
If the number of locking inserts is reduced to lower manufacturing costs, then the economy of the assembly is improved, but the pressure resistance and attachment reliability deteriorate
Solution Approach 1:
The patent optimizes the geometric parameters of the locking insert (angle of incidence, hook dimensions, thickness) to maximize the mechanical efficiency of each insert. This allows achieving the required pressure resistance with a reduced number of inserts, typically 3-5 per seal, thereby lowering manufacturing costs while maintaining reliability
Solution Approach 2:
The use of hardened steel material with superior mechanical properties enables each insert to bear higher loads. This material selection compensates for the reduced number of inserts, maintaining the required pressure resistance and attachment reliability while reducing overall component count and cost
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 cost-effective sealed and locked assembly with improved attachment and pressure resistance, maintaining low reaction angles across varying clearances, thus reducing the number of inserts needed and minimizing manufacturing costs.
Implementation Method 1
the head comprises a stop tooth, adapted to be applied on the connecting hollow when the foot hooks onto the outer surface of the spigot
Implementation Method 2
the higher this reaction angle, measured relative to the radial direction, the more the locking resists the internal pressure of the fluid flowing through the assembly
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Sealed and locked assembly comprising - a spigot end (4) of a first pipe element, - a socket end (8) of a second pipe element and - a composite sealing gasket (12) for sealed and locked assembly between the spigot end (4) and the socket end (8), the socket end comprising an anchoring groove (32) defined by a bottom surface (44) and a front surface (40), and the composite sealing gasket comprising - a ring made of elastic material extending along a central axis (X-X), having a gasket body (64) and an anchoring heel (66), and - at least one locking insert (62) for locking the joint between the spigot end (4) and the socket end (8), the locking insert being embedded at least partially in the gasket body (64), the locking insert comprising: - a radially external head at least partially embedded in the gasket body (64) and extending into the anchoring groove (32) of the socket end, and - a radially internal foot designed to rest against the spigot end and comprising at least a first catching tooth (82, 84, 86) for catching on an outer surface (20) of the spigot end (4), and the head comprising a radial projection, the assembly being characterised in that the anchoring groove (32) is defined by an inclined surface, the inclined surface and the front surface (40) together forming a connecting recess and an angle that is less than 180°, in that the head comprises a stopping tooth designed to rest on the connecting recess when the foot catches on the outer surface of the spigot end, and in that the stopping tooth and the radial projection are arranged such that, for any diameter of the bottom surface (44) of the socket end and the outer surface (20) of the spigot end within a range of manufacturing tolerances and in a meridian cross-sectional view, the stopping tooth of the locking insert (62) abuts in the connecting recess.