Pipe Sealing Tool With Nested Clamps For Weld Stress Testing
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Solution Overview
Problem
There is a need for an apparatus that can easily seal the open end of a long pipe for conducting stress tests, particularly to simulate worst-case scenarios by exerting axial stresses on welds without causing damage to the pipe, and existing solutions are either cumbersome or ineffective for large nozzles.
Innovation Solution
The apparatus employs a combination of external and internal clamping means using segmental gripper rings and compression rings with cooperating ramped surfaces to frictionally engage the pipe's surfaces, creating a sealed environment that can withstand high pressurization and apply axial stresses during testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal plate is placed on the inner surface and another on the outer flange portion to seal the nozzle volume, then accurate weld testing is achieved, but the apparatus becomes too large and heavy for convenient use on large nozzles
Solution Approach 1:
The sealing apparatus is divided into two separate sealing means: an internal sealing means positioned inside the pipe and an external sealing means positioned outside the pipe. This segmentation allows each sealing component to be smaller and lighter, while together they achieve the complete seal needed for accurate weld testing.
Solution Approach 2:
The internal sealing means is nested within the pipe, utilizing the internal space, while the external sealing means is positioned on the outer surface. This nested arrangement eliminates the need for large external apparatus, reducing overall size and weight while maintaining sealing effectiveness.
2Reliability
If a clamp is tightened against the exterior surface of a pipe to seal it, then sealing is achieved, but the clamp may slip off the pipe end under high pressurization
Solution Approach 1:
The sealing approach transitions from purely axial clamping to a combination of axial and radial forces. The external sealing means applies radial force against the pipe's outer surface, while the internal sealing means applies radial force from the inside, creating a multi-dimensional constraint that prevents slippage under high pressure.
Solution Approach 2:
The sealing surfaces are designed with specific local properties: the external sealing means contacts the outer peripheral surface with a tailored contact area, while the internal sealing means contacts the inner peripheral surface with a complementary contact area. This localized optimization ensures high friction and grip without requiring complex overall mechanisms.
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 effectively seals the pipe end, allowing for accurate stress testing of welds by applying both radial and axial forces, ensuring the integrity of the seal and the pipe's integrity without causing damage, and is adaptable for use on various pipe sizes.
Implementation Method 1
an outer compression ring compresses the gripper ring against the pipe end's external surface
Implementation Method 2
an annular deformable resilient seal means for positioning between the back plate and the inner compression ring
Implementation Method 3
said rings having cooperating contacting ramped surfaces
Data Source
AI summary
An apparatus for sealing an open end of a pipe includes an external clamp for frictionally being secured to the exterior surface of the pipe and an internal clamp for frictionally being secured to the interior surface of the pipe. A sealing plate, connected to one or both of the clamps seals the open end of the pipe. The apparatus further includes a means for pressurizing the interior of the pipe. A method of sealing and pressurizing the pipe is also provided.