Down-the-hole Drilling Flushing Flow Arrangement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In down-the-hole drilling, particularly in pile drilling, the careless use of flushing air leads to overdrilling and reduced weight-carrying capacity of piles due to air infiltration in cohesive soils, posing safety risks and structural damage, while traditional drill bits fail to effectively control air circulation, causing inefficiencies and safety concerns.
Innovation Solution
The method involves a drilling apparatus with a flushing flow arrangement that directs the flushing medium between the pilot and reamer, utilizing a guide surface arrangement to control air flow and prevent return flow, ensuring efficient circulation and minimizing air infiltration into the soil, thereby preventing overdrilling and structural damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If flushing air is used for down-the-hole drilling, then drilling efficiency is improved, but air infiltration into cohesive soils causes overdrilling and reduced weight-carrying capacity
Solution Approach 1:
The flushing flow arrangement is segmented into distinct functional zones: a first flushing means directs air onto the drilling surface, while a second flushing means creates a controlled return path for air and drilling waste. This segmentation allows the air flow to be divided into productive drilling function and controlled containment function, preventing uncontrolled infiltration into cohesive soils while maintaining drilling efficiency.
Solution Approach 2:
The patent introduces an intermediary containment structure (the second flushing means and associated flow control mechanisms) that mediates between the high-energy flushing air and the vulnerable cohesive soil. This intermediary system captures and redirects air flow, preventing direct contact between flushing air and soil, thus eliminating the harmful infiltration effect while preserving the beneficial drilling action.
2Device complexity
If traditional drill bits are used, then construction is simple, but they fail to control air circulation effectively
Solution Approach 1:
The drilling apparatus integrates multiple functions into a unified system: the first drilling means performs center hole drilling, the second drilling means performs reaming, and the flushing flow arrangement simultaneously cools both drilling surfaces, removes waste, and controls air circulation. This multi-functional integration achieves reliable air circulation control without requiring separate complex subsystems, maintaining reasonable construction simplicity.
Solution Approach 2:
The patent merges the flushing medium delivery system with the waste removal system into a single integrated flushing flow arrangement. The same air flow that cools and lubricates the drilling surfaces also carries away drilling waste and controls circulation patterns. This merging simplifies the overall construction compared to having separate systems for each function, while achieving reliable air circulation control.
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
This approach enhances safety and efficiency by preventing air from entering the soil, reducing overdrilling, and maintaining structural integrity, allowing for safer and more controlled down-the-hole drilling operations.
Implementation Method 1
a flushing medium is being brought onto a drilling surface and returned from the drilling surface together with the drilling waste by axially directed flow arrangements
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
The invention relates to a method and apparatus for down-the- hole drilling, the drilling being carried out by an apparatus, having a drilling device (1) that comprises a casing part (2) and an essentially inside thereof existing drilling unit (3), at the drilling head of which there are at least first drilling means (4) for drilling a centre hole, second drilling means (5) for reaming the centre hole for the casing part (2) and a flushing flow arrangement (6) that comprises first flushing means (6a) for leading of a flushing medium onto a drilling surface (P) and second flushing means (6b) for returning of the flushing medium and drilling waste at least partly internally inside the casing part (2). The first drilling means (4) are removably coupled with the second drilling means (5) in order to enable removal thereof from the hole. The casing part (2) is arranged to be drawn into a hole to be drilled by the drilling unit (3). The flushing medium is being brought onto the drilling surface (P) and returned therefrom by axially directed (s) flow arrangements (6a; 6a', 6b; 6b'), disposed in a cross-section view, on an outer periphery of the first drilling means (4) and/or in an inner periphery of the second drilling means (5).