Down-the-hole Drilling Airflow Control via Counterpart Surface
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Solution Overview
Problem
Down-the-hole hammer drilling faces issues with excessive material removal and air leakage in cohesive soils, leading to structural damage and inefficiencies due to high air velocity and poor air circulation control, particularly in overburden drilling where air easily penetrates the ground.
Innovation Solution
The method involves a drilling apparatus with a drilling head featuring a counterpart surface arrangement that alters the flow direction of flushing air, reducing kinetic energy and preventing air from directly hitting the soil, utilizing a reamer with a radially continuing drilling surface and distribution channels to manage air flow effectively within the casing pipe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high velocity flushing air is used to remove drilling waste, then drilling efficiency is improved, but air leakage into cohesive soil occurs causing structural damage
Solution Approach 1:
A flow direction changing arrangement acts as an intermediary between the flushing air source and the drilling surface. This intermediary component redirects the air flow path, preventing direct high-velocity air from penetrating into cohesive soil while still effectively removing drilling waste at the drilling surface.
Solution Approach 2:
The flow direction changing arrangement modifies the flow parameters of the flushing air by altering its direction before it reaches the drilling surface. This changes the air flow characteristics to reduce kinetic energy and prevent harmful air leakage into the soil while maintaining effective waste removal capability.
2Productivity
If pressurized air is directed onto drilling surface for waste removal, then drilling waste is effectively removed, but excessive material removal occurs leading to overdrilling
Solution Approach 1:
The flow direction changing arrangement creates localized control over air flow properties. By redirecting air flow in specific directions, it concentrates the flushing action where needed at the drilling surface while preventing excessive air penetration into surrounding soil, thus avoiding overdrilling and excessive material removal.
3Productivity
If flushing air velocity is increased to improve air circulation, then drilling waste removal is enhanced, but air easily penetrates ground causing loss of flushing effectiveness
Solution Approach 1:
The flow direction changing arrangement serves as an intermediary that optimizes air circulation while preventing direct air penetration into the ground. It redirects air flow to maintain effective circulation for waste removal without allowing high-velocity air to escape and lose effectiveness.
4Productivity
If high velocity flushing air is used, then drilling waste is rapidly removed, but kinetic energy causes air to directly hit soil creating harmful effects
Solution Approach 1:
The flow direction changing arrangement changes the velocity vector parameters of the flushing air by redirecting its flow direction. This reduces the kinetic energy component directed into the soil while maintaining the waste removal function, thereby eliminating harmful effects on surrounding structures.
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 minimizing overdrilling and structural damage, allowing controlled air circulation and effective soil removal without damaging surrounding structures, thus enabling reliable and precise down-the-hole drilling operations.
Implementation Method 1
a pneumatic flushing flow arrangement (6) for leading of drilling waste by influence of pressurized air at least partly upward
Implementation Method 2
Flushing air is led while being led onto the drilling surface P1, P2 of the first and/or second drilling means into a counterpart surface arrangement X existing essentially at an end of a drilling unit 3, particularly in order to decrease kinetic energy thereof by changing its flow direction prior to drifting thereof into the ground
Data Source
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AI summary
The invention relates to a method 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 at least during a drilling situation 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 center hole, second drilling means (5) for reaming the center hole for the casing part (2) and a pneumatic flushing flow arrangement (6) for leading of drilling waste by influence of pressurized air at least partly upward, whereby the first drilling means (4) are coupled with the second drilling means (5) first of all power-transmittedly in order to carry out cooperation thereof at least during a drilling situation with the second drilling means (5) for a rotational motion (w4), a feeding motion (z4) and/or a hammering motion (t4), and on the other hand removably in order to enable removal thereof from the hole. Furthermore the casing part (2) is arranged to be drawn into a hole to be drilled by the drilling unit (3). Particularly direct aiming of a flushing air flow (HV) at the soil is being prevented by directing the flushing air at an end of the drilling unit (3) into a counterpart surface arrangement (X) on the drilling surface (Pl and/or P2) existing of the first and/or second drilling means in order to decrease kinetic energy of the flushing air flow (HV) by changing its flow direction on the drilling surface prior to drifting thereof into the ground. The invention relates also to an apparatus applying the method.