Tube Scraper With Radially Moveable Arms For Heat Exchanger Cleaning
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Solution Overview
Problem
Hard deposits such as rust and scale build up on the interior surfaces of heat exchanger tubes, reducing thermal efficiency and restricting fluid flow, and existing methods are inadequate for effectively removing these deposits.
Innovation Solution
A tube scraper with radially moveable scraper blade arms and a propelling piston, featuring inclined ratcheting surfaces and tapered blades that maintain engagement with the tube wall, ensuring an overlapping scraping pattern to cover the entire circumference and effectively remove hard deposits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single scraper blade is used, then the device complexity is reduced, but the scraping coverage and effectiveness are insufficient
Solution Approach 1:
The scraper blade is divided into multiple segments (first scraper blade and second scraper blade) arranged radially around the central axis. Each segment independently scrapes different portions of the tube interior surface, increasing overall scraping coverage while maintaining manageable device complexity through modular segmentation.
Solution Approach 2:
The scraper blades are arranged in a radial configuration around the central axis, transitioning from a single-point contact to multi-point circumferential contact. This dimensional arrangement allows simultaneous scraping of multiple locations around the tube circumference, dramatically increasing scraping coverage.
2Device complexity
If fixed scraper blades are used, then the device structure is simplified, but the ability to maintain engagement with tube wall during propulsion is reduced
Solution Approach 1:
The scraper blades are mounted on radially moveable arms that can dynamically adjust their position. As the scraper is propelled through the tube, the blades automatically engage and disengage from the tube wall based on contact forces, maintaining reliable engagement without requiring complex fixed mounting structures.
Solution Approach 2:
The radial position of the scraper blades is made variable through the moveable arm mechanism. The blades can change their radial distance from the central axis, allowing them to adapt to different tube diameters and maintain stable engagement with the tube wall throughout the scraping process.
3Device complexity
If non-overlapping blade arrangement is used, then the device complexity is reduced, but the completeness of tube surface scraping is insufficient
Solution Approach 1:
The scraper blades are pre-positioned on the radially moveable arms at specific angular intervals before the scraping operation begins. This preliminary arrangement ensures that as the scraper progresses through the tube, the blades naturally create overlapping scraping paths that comprehensively cover the entire tube interior surface.
Solution Approach 2:
The scraping actions of multiple individual blades are combined through their radial arrangement and overlapping paths. The first scraper blade and second scraper blade work simultaneously, with their scraping zones overlapping to ensure complete coverage of the tube interior surface, merging multiple scraping actions into a comprehensive cleaning effect.
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 effectively removes hard deposits from the interior surfaces of heat exchanger tubes, maintaining thermal efficiency and fluid flow by using a dynamic mechanism that ensures all deposits are scraped and ejected, with the ability to fit various tube sizes using a limited number of scraper sizes.
Implementation Method 1
a piston sealing the scraper against the tube wall for pneumatically or hydraulically propelling the scraper through the tube
Implementation Method 2
a piston sealing the scraper against the tube wall for pneumatically or hydraulically propelling the scraper through the tube
Implementation Method 3
the engaging blade and arbor ratcheting surfaces cooperate to force the blade edges radially outward keeping them in scraping engagement with the tube wall
Implementation Method 4
mechanical scraping using a projectile driven through the tube... The projectile is fitted with scrapers engaging the tube interior wall for removing deposits
Data Source
AI summary
A tube scraper for removing deposits from the interior surface of heat exchange tubes, the scraper being fitted with a set of diverging scraper blade arms mounted on an arbor in nested relationship such that scraper blades have overlapping scraping edges.