Retractable Lance Support for Heat Exchanger Cleaning
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Solution Overview
Problem
Existing heat exchanger tube cleaning machines are limited in their ability to approach the tube bundle closely due to stacking guide supports, leading to inefficient cleaning, safety hazards, and high operational costs, as they require manual disassembly and use of high-pressure lances that can be dangerous and physically exhausting.
Innovation Solution
A twin, rigid lance machine with a pair of parallel metal lances driven by a transversal drive mechanism, supported by retractable doors that interlock to prevent uncontrolled movement, allowing the drive mechanism to approach the tube bundle closely and rotate at user-controllable speeds for effective cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If guide supports are stacked up as the lance moves into the tube, then the lance is supported and prevented from buckling, but the machine is limited in how close the prime mover can get to the tube bundle entry
Solution Approach 1:
The guide supports are made retractable rather than fixed, allowing them to dynamically adjust their position. During lance insertion, the supports retract to clear the path, and during lance support, they extend to provide guidance. This dynamic behavior resolves the contradiction by eliminating the need for stacked guide supports while maintaining lance support functionality.
Solution Approach 2:
The guide support system is segmented into multiple independent retractable units distributed along the lance path. Each segment can independently retract and extend, allowing the lance to pass through cleared sections while being supported by extended sections. This segmentation enables the prime mover to approach close to the tube bundle without requiring a continuous stack of guide supports.
2Productivity
If manual cleaning with high pressure cleaning lance is used, then cleaning capability is achieved, but worker safety is compromised and physical exhaustion occurs
Solution Approach 1:
The machine performs the cleaning function autonomously without requiring manual operation of the high pressure lance. The automated prime mover inserts and operates the lance, eliminating direct worker exposure to high pressure water jets and hazardous chemicals. The system serves itself by automating the dangerous cleaning task while maintaining effective cleaning capability.
Solution Approach 2:
Manual mechanical operation of the cleaning lance is replaced with an automated mechanical system. The prime mover mechanism automatically feeds, rotates, and retrieves the lance, substituting human physical labor with a controlled mechanical system. This substitution eliminates physical exhaustion and safety hazards associated with manual high pressure lance operation.
3Length of moving object
If the prime mover is moved forward to advance the lance, then cleaning reach is improved, but uncontrolled transverse movement occurs without proper support
Solution Approach 1:
The guide supports dynamically retract during lance advancement to prevent interference, then extend to provide transverse stability. This dynamic adjustment ensures the lance can be advanced to the maximum possible distance while maintaining controlled transverse movement through the extended guide supports at the advancement position.
Solution Approach 2:
The guide supports are positioned and extended in advance at the target advancement position before the lance reaches it. This preliminary positioning ensures that when the lance is advanced to its maximum reach, stable transverse support is already in place to prevent uncontrolled movement, rather than requiring support throughout the entire advancement path.
Data Source
AI summary
A pair of parallel metal lances is driven by a transversal drive into and out of heat exchanger tubes. The lances are supported by a plurality of spaced apart, retractable door supports so that the transversal drive mechanism can approach the tube sheet of the heat exchanger tubes as closely as possible. A pair of rotational drive motors rotates the lances at a user controllable speed. As the lances are moved into the tubes, the interlocked support doors retract one at a time, sequentially. Similarly, as the lances are withdrawn from the tubes, the support doors close one at a time in an interlocked fashion.