Flexible Scraper Pig Studs for Refinery Tube Cleaning
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Solution Overview
Problem
Existing scraper pigs for cleaning refinery furnace tubes are limited in their ability to effectively navigate serpentine paths and provide full 360° coverage, often leaving behind contamination due to inflexible designs and loose studs, which reduces cleaning efficiency and requires frequent replacement.
Innovation Solution
A scraper pig with a cylindrical core and a casing containing projecting studs, made from polyurethane/isocyanate compounds, where the studs are securely anchored and arranged in a pattern optimized for 360° coverage using Computer Aided Design, allowing for flexibility and firmness to navigate complex tube geometries while preventing stud displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional scraper pigs with loose studs are used, then the pig can be manufactured with simpler structure, but the studs become dislodged during operation reducing cleaning effectiveness
Solution Approach 1:
The patent employs a composite construction where a rigid casing made from hardenable material (such as epoxy resin or polyester resin) is bonded to a flexible core. The studs are securely embedded within this composite casing structure, which provides both mechanical strength and flexibility. This composite approach ensures studs remain firmly attached during operation while maintaining the necessary flexibility to navigate serpentine tube paths.
Solution Approach 2:
The patent utilizes a flexible core surrounded by a hardenable material casing. The flexible core allows the pig to bend and conform to the serpentine geometry of furnace tubes, while the hardenable material casing provides structural integrity and secure stud retention. This flexible shell design enables the pig to navigate complex tube geometries without compromising stud attachment reliability.
2Productivity
If the pig body is made rigid for firm scraping action, then cleaning effectiveness improves, but the pig cannot navigate serpentine paths effectively
Solution Approach 1:
The patent applies local quality by creating a segmented structure with different material properties in different regions. The core is made flexible to navigate bends, while the outer casing with studs is made rigid to provide effective scraping action. This local differentiation of material properties allows the pig to simultaneously achieve both flexibility for navigation and rigidity for cleaning effectiveness.
Solution Approach 2:
The composite construction combines flexible core material with rigid hardenable material casing. This allows the pig body to exhibit both flexibility (from the core) for navigating serpentine paths and rigidity (from the casing) for maintaining firm scraping action against tube surfaces, thereby achieving both adaptability and cleaning productivity.
3Productivity
If studs are arranged for maximum 360° coverage, then cleaning coverage improves, but the manufacturing precision required increases
Solution Approach 1:
The patent implements preliminary action by pre-forming the stud pattern within the hardenable material casing before the final pig assembly. The studs are embedded in the casing during the casting or molding process, ensuring precise and uniform spacing that achieves 360° coverage. This preliminary formation of the stud pattern eliminates the need for post-assembly adjustments and ensures consistent manufacturing precision.
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 scraper pig achieves thorough and efficient cleaning of refinery furnace tubes by ensuring studs remain securely attached, providing full 360° coverage and reducing the need for frequent replacement, while allowing for tailored designs to suit specific tube geometries, thereby enhancing cleaning efficiency and extending the pig's operational life.
Implementation Method 1
a hardenable material is then cast around the studs in the area between the core and the strap, the hardenable material is hardened to provide a casing bonded to the core
Data Source
AI summary
A scraper pig for cleaning tubes and pipelines comprising a flexible core provided with a casing in which scraper studs are embedded in a manner whereby they protrude sufficiently to perform a cleaning action when they are propelled through the tube. A method for the manufacture of the pig and the design of the stud is also provided.