Curved Sludge Grooves in Percussive Drill Bits
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Solution Overview
Problem
Percussive drill bits face challenges in effectively transporting rock sludge rearward during drilling, leading to recrushing of rock fragments, shortened operational lifetime, and increased risk of borehole collapse during extraction.
Innovation Solution
A drill bit design featuring an axially rearward skirt with obliquely aligned ribs and channels that facilitate the rearward transport of rock debris and flushing fluid, preventing recrushing and ensuring smooth extraction by directing the sludge into a helical flow pathway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If traditional straight sludge grooves are used, then the structure is simple, but the rock sludge cannot be effectively transported rearward leading to recrushing and shortened operational lifetime
Solution Approach 1:
The patent applies curvature by bending the sludge grooves in a helical pattern around the drill bit axis rather than using straight grooves. This curved configuration creates a screw-conveying action that effectively transports rock sludge rearward during rotation, preventing recrushing and extending operational lifetime while adding moderate structural complexity
Solution Approach 2:
The invention transitions from straight linear grooves to three-dimensional helical grooves that wrap around the drill bit. This adds a circumferential dimension to the sludge transport path, creating a more effective conveying mechanism that moves sludge both axially rearward and circumferentially around the bit axis
2Duration of action of moving object
If rock sludge is not effectively transported rearward, then the structure remains simple, but recrushing of rock fragments occurs shortening operational lifetime
Solution Approach 1:
The helical curvature of the grooves creates a screw-conveying action that actively propels sludge rearward during drill bit rotation, significantly improving sludge transport efficiency and preventing the productivity loss that would occur with straight grooves
3Reliability
If non-transported sludge accumulates, then no additional structure is needed, but borehole collapse risk increases and extraction becomes difficult
Solution Approach 1:
The helical groove configuration creates continuous rearward transport of sludge during both drilling and extraction operations, preventing sludge accumulation that could cause borehole collapse or extraction difficulties, thereby improving reliability without requiring additional active sludge management systems
Solution Approach 2:
The grooves provide continuous sludge transport throughout the drilling and extraction cycles, ensuring that rock fragments are constantly moved away from the cutting region and borehole wall, maintaining borehole stability continuously rather than intermittently
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 extends the operational lifetime of the drill bit, prevents borehole collapse, and ensures smooth rearward extraction by effectively managing the transport of rock sludge and flushing fluid, reducing the risk of the drill bit getting stuck.
Implementation Method 1
directing the sludge into a helical flow pathway
Data Source
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AI summary
A percussive drill bit having a head and an axially rearward skirt. A plurality of ribs project radially outward at the skirt and define lengthwise extending channels. The ribs and channels, in the lengthwise direction are curved or angled to deviate from a longitudinal axis of the drill bit to facilitate rearward transport of fines and flushing fluid.