Rotatable Heated Sheet Applicator for Pipeline Weld Coating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for coating pipeline welds with a synthetic resin coating face challenges such as difficulty in achieving high adhesion of the third layer to the factory coating and previous layers, air trapped between layers, and limitations in applying coatings to large diameter pipes due to equipment constraints and temperature control issues.
Innovation Solution
A machine with a rotatable sheet application roller and mat system that applies a heated sheet circumferentially around the pipe joint, ensuring excellent adhesion through controlled temperature and pressure, and accommodating various pipe diameters with adjustable components to prevent air entrapment and burn-through.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-layer coextruded sheathing is used for field joint coating, then corrosion protection is improved, but the applicator roller needs to be at least the pipe diameter or bigger which restricts the ability to coat large diameter pipes
Solution Approach 1:
The applicator roller is made adjustable in diameter through an extension mechanism that can be extended or retracted. This allows the roller to adapt its size to match different pipe diameters, enabling the coating of both small and large diameter pipes with the same equipment while maintaining the multi-layer corrosion protection system.
2Reliability
If a heat assisted helically wrapped tape application system is used, then field joint coating is achieved, but air can be trapped between overlapping jointed layers reducing coating effectiveness
Solution Approach 1:
The thermoplastic coating material undergoes phase transition from solid to molten state during application. The material is heated to its melting point, allowing it to flow and conform to the pipe surface and overlap areas, thereby expelling trapped air bubbles and ensuring complete wetting and adhesion to the factory coating.
Solution Approach 2:
The coating material is preheated in an oven before application to the pipe. This preliminary heating ensures the material reaches the appropriate temperature for optimal flow characteristics and adhesion, allowing air to be expelled before the material sets, thereby preventing air entrapment in the final coating.
3Reliability
If the applicator roller is made large to accommodate multi-layer sheathing, then coating capability is improved, but the machine cannot coat large diameter pipes when line pipes are already landed and welded
Solution Approach 1:
The applicator roller incorporates an extension mechanism that allows dynamic adjustment of the roller diameter. The roller can be extended to match large pipe diameters or retracted for smaller pipes, providing versatility to coat landed pipes of various sizes without requiring multiple specialized rollers.
Solution Approach 2:
The applicator roller is divided into modular sections that can be independently adjusted or reconfigured. This segmentation allows the roller to adapt to different pipe diameters by extending or retracting specific sections, enabling the same machine to effectively coat both small and large diameter landed pipes.
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 machine achieves strong adhesion of the third layer to the factory coating and previous layers, capable of withstanding significant forces, and can be used on pipes with diameters from 50.8 mm to 304.8 mm, ensuring a continuous and effective corrosion protection system.
Implementation Method 1
a sheet to be applied circumferentially around a pipe joint, the machine comprising: an oven configured to heat the sheet
Implementation Method 2
a roller pressed against the pipe in order to apply the heated sheet onto the pipe joint
Implementation Method 3
ensuring excellent adhesion of the third layer to the factory coating and previous layers
Data Source
AI summary
A pipe joint coating for welded ends of pipes forming a pipeline. A last and third layer of a 3LPP coating system covering at least a circumferential weld area of the pipe joint is a heated sheet applied around the pipe with a machine including a mounting frame and a transport carriage rotatably movable on the mounting frame to move circumferentially about the pipe joint, and a roller applying an adjusted pressure to the sheet against the pipe and adapting to eccentricity or ovality of the pipe. The sheet is pressed below the pipe away from its overlapping ends, a first part of the sheet is then applied when the roller is rolled in a first direction, and a second part of the sheet is applied by the roller rolled back in the reverse direction around the pipe. The sheet is dimensioned to obtain an overlapped area between its extremities.