Mechanical Joint Gland Restraint for Pipe Pullout Without Cracking
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Solution Overview
Problem
Mechanical joint pipe connections lack a positive retention mechanism, leading to potential seal compromise and pipe deformation or cracking under high tension forces, such as water hammer, which can result in leaks or environmental contamination.
Innovation Solution
A gland with a joint restraint assembly featuring a restraint base, gripper, and spring clip that engages the pipe surface to prevent removal, providing a secure connection without exerting excessive stress on the pipe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a joint restraint mechanism is incorporated to provide positive retention, then the reliability of the connection is improved, but the stress on the pipe length increases leading to deformation and cracking
Solution Approach 1:
The patent changes the parameters of the restraint mechanism by using a cam-shaped surface with a controlled angle (10-45 degrees) to modify how force is applied to the pipe. This angular parameter change allows the gripper to engage the pipe at an optimized angle that provides retention while distributing stress more favorably compared to conventional perpendicular or acute-angle restraints.
Solution Approach 2:
The patent applies local quality by creating a specialized engagement zone on the pipe surface through the cam-shaped gripper design. The cam surface contacts only a specific portion of the pipe circumference at an optimized angle, concentrating the retention function in a localized area while distributing the stress away from critical pipe regions. This localized engagement approach provides effective restraint without subjecting the entire pipe to high stresses.
2Reliability
If existing joint restraint mechanisms are used to prevent pipe removal, then the seal reliability is improved, but the pipe length undergoes deformation and creep during installation and operation
Solution Approach 1:
The patent modifies the geometric parameters of the restraint mechanism by implementing a cam-shaped surface with a specific angle range (10-45 degrees). This parameter change transforms the force application geometry, allowing the gripper to engage the pipe in a manner that secures the connection while minimizing deformative stress. The optimized angle prevents excessive radial and axial forces that would cause pipe deformation and creep.
Solution Approach 2:
The patent introduces dynamic characteristics to the restraint mechanism through the cam-shaped gripper design. As the gland is assembled and tightened, the gripper naturally progresses along the cam surface, allowing for controlled engagement and adaptation to the pipe's position. This dynamic engagement process reduces impact forces and allows the mechanism to self-adjust, preventing sudden deformations and creep that occur with rigid, static restraint mechanisms.
3Reliability
If a positive retention mechanism is added to the mechanical joint, then the connection security is improved, but the device complexity increases
Solution Approach 1:
The patent merges the joint restraint function with the existing gland structure by integrating the cam-shaped gripper into the gland body. Rather than adding a separate, independent restraint mechanism, the design combines the retention functionality with the components already present in the mechanical joint assembly. This merging approach provides positive retention while minimizing the increase in overall device complexity.
Solution Approach 2:
The patent implements multi-functionality by designing the cam-shaped gripper to perform multiple functions: it provides joint restraint to prevent pipe removal, maintains seal pressure through controlled engagement, and distributes loads to prevent pipe deformation. This universal component serves several critical functions simultaneously, avoiding the need for multiple separate mechanisms and thereby limiting the increase in device complexity.
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 ensures a secure and reliable seal by preventing pipe removal from the socket, reducing the risk of leaks and contamination while minimizing stress on the pipe, thus enhancing the durability of the connection.
Implementation Method 1
a spring clip disposed within the restraint pocket, the spring clip biasing the gripper to rotate inwards towards the gland axis
Data Source
AI summary
A mechanical joint includes a piping element, the piping element including an element flange, the piping element defining a socket extending inwards from the element flange; a pipe length, the pipe length extending through the element flange into the socket, the pipe length defining an outer pipe surface; and a gland, the pipe length extending through the gland, the gland including a joint restraint assembly, the joint restraint assembly including a restraint base; and a gripper disposed within the restraint pocket, the gripper configured to rotate in the restraint pocket, the gripper further configured to engage the outer pipe surface to prevent removal of the pipe length from the socket.