Percussive Drill Bit Lateral Flushing Channel Design
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Solution Overview
Problem
Drilling in sensitive ground conditions poses challenges due to over-drilling and unintended damage from flushing fluid, which can remove excessive ground material and weaken existing structures, particularly in soft ground and clay formations.
Innovation Solution
A drill bit design featuring a lateral flushing channel that directs flushing fluid from a central channel to the circumference, minimizing flow resistance and creating a pressure differential to enhance the conveyance of drill cuttings, thereby reducing the risk of over-drilling and structural damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If flushing fluid is used to flush drill cuttings from the drill hole, then the drill bit can effectively act on the ground, but excessive ground material is removed causing over-drilling in soft ground conditions
Solution Approach 1:
The flushing fluid flow is segmented into multiple lateral flushing channels distributed around the drill bit circumference, allowing controlled fluid distribution to different regions. This segmentation enables precise management of where and how flushing fluid acts on the ground, preventing excessive removal of ground material while maintaining effective cuttings removal.
Solution Approach 2:
Different regions of the drill bit are assigned different flushing functions through laterally distributed flushing channels. The flushing fluid is delivered to specific local zones rather than uniformly across the entire face, allowing optimization of ground interaction in soft conditions while maintaining cuttings removal efficiency in other areas.
2Productivity
If flushing fluid is used to flush drill cuttings, then drilling effectiveness is improved, but flushing fluid travels long distances along ground formations weakening existing structures
Solution Approach 1:
The harmful effect of flushing fluid traveling long distances is extracted and eliminated by redirecting the fluid flow through laterally distributed channels that discharge closer to the drill bit. This prevents the flushing fluid from penetrating deep into surrounding ground formations and reaching existing structures.
Solution Approach 2:
The lateral flushing channels act as intermediaries that control and redirect the flushing fluid flow path. Instead of allowing fluid to travel uncontrollably along ground formations, the channels mediate the fluid's journey, directing it to discharge at controlled locations near the drill bit face.
3Device complexity
If lateral flushing channel is designed with sharp directional transitions, then the channel structure is simpler, but flow resistance increases reducing flushing fluid capability to convey drill cuttings
Solution Approach 1:
The lateral flushing channels incorporate smooth curved transitions instead of sharp angular changes. This curvature design reduces flow separation and turbulence, minimizing pressure losses while maintaining a relatively simple channel geometry that is easy to manufacture.
4Productivity
If flushing fluid flow rate via lateral flushing channel is increased to enhance cuttings conveyance, then pressure differential increases improving cuttings removal, but risk of over-drilling and structural damage increases
Solution Approach 1:
The total flushing fluid flow is segmented and distributed across multiple lateral channels, allowing the system to achieve high total flow rates for effective cuttings removal while each individual channel operates at controlled pressures. This distribution prevents concentration of high pressure in one location, reducing the risk of over-drilling and structural damage.
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 design increases the flushing fluid flow rate and pressure differential, effectively drawing drill cuttings to the surface while minimizing the risk of over-drilling and structural damage, especially in sensitive ground conditions.
Implementation Method 1
the flushing fluid exiting the channel may be directed for enhancing a pressure differential between the surrounding of the circumference of the head portion and the face surface
Implementation Method 2
flushing fluid flow via the lateral flushing channel is facilitated by providing smooth directional transitions
Implementation Method 3
flushing fluid exiting the channel may be directed for enhancing a pressure differential... flushing fluid flow via the lateral flushing channel is facilitated by providing smooth directional transitions, i.e. a smooth general contour resulting in smaller flow resistance
Implementation Method 4
Such a pressure differential acts much like a vacuum effect, drawings drill cuttings from ahead of the face surface of the head portion
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A drill bit (1) is provided, comprising a head portion (2) having a circumference (2a) and a face surface (2b), and a shank portion (3) extending longitudinally from a side of the head portion opposite to the face surface. A central flushing channel (4) extends longitudinally through the shank portion (3) and a distance within the head portion (2), and a lateral flushing channel (5) extends from the central flushing channel (4) to the circumference (2a) of the head portion (2). A first portion (5a) of the lateral flushing channel is inclined, in a flushing fluid flowing direction, towards the face surface (2b) with respect to said second portion (5b), and correspondingly, a second portion (5b) is inclined, in a flushing fluid flowing direction, towards the shank portion (3). A drill bit assembly and method of manufacturing such a drill bit is also disclosed.