Liquid Nitrogen Boring of Reinforced Concrete
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Solution Overview
Problem
When boring reinforced concrete materials, it is challenging to avoid damaging reinforcing bars and pipes integrated within the concrete, as existing methods require time-consuming preparation to identify their positions and are difficult to adjust during the boring process.
Innovation Solution
A method using a liquid nitrogen-spraying system where the liquefied fluid is sprayed to advance boring, and the spray direction is adjusted to avoid reinforcing bars and pipes, utilizing a nozzle unit with a bent or curved tip portion to guide the fluid and exploit the expansive force of vaporizing nitrogen to break the concrete while avoiding materials without fine holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a boring machine is used to bore reinforced concrete materials, then boring can be performed, but it is difficult to avoid damaging reinforcing bars and pipes integrated within the concrete
Solution Approach 1:
The invention segments the concrete structure into removable concrete portions and protected reinforcing elements by using liquid nitrogen that selectively penetrates only the concrete's porous structure, not the solid reinforcing bars or pipes, enabling separation of removal action from protected elements
Solution Approach 2:
Liquid nitrogen serves as an intermediary substance that mediates between the boring process and the concrete material, utilizing the concrete's porous structure as a pathway for the liquid nitrogen to penetrate and expand, thereby removing concrete without direct mechanical contact that could damage embedded elements
2Object-affected harmful factors
If prior identification of reinforcing bars and pipes is performed before boring, then damage can be avoided, but time-consuming preparation is required
Solution Approach 1:
The concrete material's own porous structure serves the function of guiding and containing the liquid nitrogen, making the concrete self-selective in receiving the removal agent without requiring external identification or marking of boundaries between concrete and reinforcing elements
3Object-affected harmful factors
If the boring machine contacts reinforcing bars or pipes during boring, then the boring process must be stopped and repositioned, but this reduces productivity
Solution Approach 1:
The invention replaces the mechanical contact-based boring system with a chemical-physical system using liquid nitrogen penetration and expansion, eliminating the need for mechanical force that would directly contact and potentially damage reinforcing bars or pipes, allowing continuous operation without repositioning
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
Enables efficient removal of concrete materials without damaging reinforcing bars or pipes, allowing continuous boring without prior knowledge of their positions, as the vaporized nitrogen expands within the concrete's fine holes but not in materials without holes, reducing work load and improving efficiency.
Implementation Method 1
the expansive force when the liquefied fluid vaporizes breaks the object to be removed
Implementation Method 2
The expansion rate when a liquid vaporizes is, for example, several hundred times or more
Data Source
Figure 1
Figure 2
Figure 3~3(c)
AI summary
The method for removing an object to be removed is a method for removing an object to be removed in which an object to be removed (11) is removed from a structure (10) including the object to be removed made of a material having fine holes through which a liquid can enter, and a remaining material (12) made of a material having no fine holes through which the liquid can enter and united to the object to be removed, and the method for removing an object to be removed includes: spraying a liquefied fluid (X) that vaporizes after spraying onto the object to be removed.