Hydraulic Downhole Drilling Machine Soft Start From Flush Position
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Solution Overview
Problem
Existing downhole drilling machines experience inefficient and cumbersome restarts from flush positions due to long activation distances and uncontrollable transitions, particularly in broken or fissured rock, leading to reduced drilling efficiency.
Innovation Solution
Incorporation of a pressure relief port in the slide control interface that allows the impact piston to return to its holding position with a significantly reduced activation distance by diverting pressure flow from the drive chamber to the slide control channel, facilitating smoother restarts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the drill bit stops during drilling operation (flush position), then the impact piston rests with full hydraulic force forwards against the neck of the stationary drill bit, but the activation distance required to restart the stroke mechanism is relatively long and requires relatively large force against the rock face
Solution Approach 1:
The invention extracts the harmful high pressure from the drive chamber during the restart process. By providing a pressure relief port that communicates the drive chamber with the slide control channel, the high pressure is diverted away from the impact piston, allowing it to return to the holding position without requiring large activation force and long activation distance.
Solution Approach 2:
The slide control channel acts as an intermediary to transfer pressure from the drive chamber to control the valve slide. The pressure relief port uses this channel to divert pressure away from the impact piston during restart, enabling controlled return to the holding position and facilitating easier restart from flush position.
2Productivity
If the drill bit stops during drilling operation (flush position), then the impact piston rests with full hydraulic force forwards against the neck of the stationary drill bit, but the restart process causes undesirable and cumbersome interruption reducing drilling efficiency
Solution Approach 1:
The invention extracts the harmful high pressure from the drive chamber during the restart process. By providing a pressure relief port that communicates the drive chamber with the slide control channel, the high pressure is diverted away from the impact piston, allowing it to return to the holding position without requiring large activation force and long activation distance.
Solution Approach 2:
The invention enables continuous operation by minimizing interruptions during restart. The pressure relief mechanism allows the impact piston to automatically return to the holding position and restart the stroke mechanism without requiring the drill to be pulled out or significant activation force, thereby maintaining continuous drilling action and improving productivity.
3Ease of operation
If the drill bit stops during drilling operation (flush position), then the impact piston rests with full hydraulic force forwards against the neck of the stationary drill bit, but the on-cut process requires pushing the drill bit back a long distance to reset the valve slide
Solution Approach 1:
The invention extracts the harmful high pressure from the drive chamber during the restart process. By providing a pressure relief port that communicates the drive chamber with the slide control channel, the high pressure is diverted away from the impact piston, allowing it to return to the holding position without requiring large activation force and long activation distance.
Solution Approach 2:
The invention replaces the mechanical push-back mechanism with a pressure-driven mechanism. Instead of requiring mechanical force to push the drill bit back the activation distance, the pressure relief port uses hydraulic pressure to automatically return the impact piston to the holding position, substituting mechanical action with hydraulic 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
Achieves a softer and more efficient on-cut with reduced activation distance, minimizing unwanted stoppages and enhancing drilling efficiency, especially in challenging rock conditions.
Implementation Method 1
allows the impact piston to return to its holding position with a significantly reduced activation distance by diverting pressure flow from the drive chamber to the slide control channel
Implementation Method 2
The reciprocating movement of the impact piston is trigged by the valve slide received in a valve housing. The valve slide reverses a force exerted by the pressurized liquid on the impact piston
Implementation Method 3
The impact piston has a differential pressure area balanced rear holding position in the machine housing and is constantly affected by a small hydraulic force that drives the impact piston after each stroke to move backwards from the drill bit
Data Source
AI summary
The invention relates to a pressurized liquid driven downhole drilling machine (1) with a soft start from flush position, wherein a drive surface of an impact piston (20) is alternately pressurized and pressure relieved, depending on the position of the valve slide (6) in a valve housing (4). A slide control interface (17) includes a pressure relief port (E) so that a pressure relief channel (40) is opened in the flush position between a drive chamber (30) for the impact piston and a slide control channel (4c). This allows the impact piston (20) to be partly retracted from the flush position by diverting a pressure flow from the drive chamber (30) to a control pressure surface (A2) of the valve slide (6) thereby triggering the valve slide to move from a holding position until the impact piston has moved to a balance point at which the pressure relief port (E) is closed.