Fluid-Driven Percussion Hammer Valve Stem Elastic Strain

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Solution Overview

Problem

Current hydraulic and compressed air-driven downhole hammer drills are limited in drilling depth, efficiency, and directional control, especially when used in hard formations, and are sensitive to water impurities, restricting their use in deep and directional drilling applications.

Innovation Solution

A fluid pressure-driven percussion hammer with a controlled valve system that allows for high-frequency operation, utilizing a valve plug and stem mechanism with elastic strain and inherent tension spring properties to optimize percussion energy transfer, enabling efficient drilling with water-based fluids and additives, and compatible with directional control equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If hydraulic fluid pressure is used to drive the hammer piston, then drilling efficiency and percussion energy are improved, but the system becomes sensitive to water impurities and has limited lifetime

Engineering Contradiction:
Improvedrilling efficiencyVSAvoidsensitivity to water impurities
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces a filtration system that changes the purity parameter of the hydraulic fluid by removing impurities. The filter element captures contaminants before they reach the hammer piston and valve components, allowing the system to maintain high drilling efficiency while becoming resistant to water impurities.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a filter element as an intermediary component between the hydraulic fluid source and the hammer mechanism. This mediator captures harmful impurities in the water, protecting the sensitive hydraulic components while allowing the beneficial hydraulic pressure to drive the hammer piston effectively.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Length of stationary object

If compressed air is used to drive the hammer drill, then drilling depth is extended, but drilling speed decreases and directional control is lost

Engineering Contradiction:
Improvedrilling depthVSAvoiddrilling speed
Core Design Contradiction:
Length of stationary objectVSProductivity

Solution Approach 1:

The patent employs hydraulic principles using water-based fluid to drive the hammer piston, replacing compressed air. This hydraulic system maintains high drilling speed while achieving greater drilling depth through optimized pressure transmission and reduced energy loss in the drill string.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the driving medium from compressed air to hydraulic fluid, fundamentally altering the pressure transmission characteristics. This parameter change enables both high drilling speed and extended depth by reducing compressibility effects and improving energy transmission efficiency through the drill rod column.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If high percussion energy is supplied to the drill bit, then rock destruction efficiency is improved, but energy is lost as waves propagating through the drill rod

Engineering Contradiction:
Improverock destruction efficiencyVSAvoidenergy loss as waves
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent segments the energy transmission path by introducing a heavy hammer piston that concentrates percussion energy at the drill bit interface. This segmentation prevents energy from propagating as waves through the entire drill rod column, localizing the energy delivery where it is needed for rock destruction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses the weight of the hammer piston as a counterbalancing mass that concentrates kinetic energy into focused percussion blows. This heavy moving mass absorbs and redirects energy that would otherwise propagate as waves, delivering maximum percussion energy to the drill bit while minimizing energy loss through the drill string.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

4Productivity

If the valve plug closes the bore in the upstream direction, then percussion energy is optimized, but the valve stem must withstand high stress and requires precise positioning

Engineering Contradiction:
Improvepercussion energyVSAvoidvalve stem stress
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent positions the valve plug to close the bore before the hammer piston reaches maximum upstream displacement. This timing cushioning prevents excessive stress buildup in the valve stem by ensuring the pressure seal is established while the piston is still moving, reducing the peak forces the valve stem must withstand.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The valve plug performs the sealing action preliminarily, closing the bore in advance of the main percussion event. This preliminary closure establishes the pressure containment needed for optimal percussion energy transfer while allowing the valve stem to be designed for lower peak stresses rather than maximum operating pressures.

Inventive Principle:
Principle #10Preliminary action

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 solution enables drilling 60% quicker and with 60% less energy consumption compared to existing water-propelled hammer drills, while maintaining efficiency and extending the drilling depth and diameter capabilities, suitable for deep-water geothermal and oil/gas resource extraction.

Implementation Method 1

said valve stem being long and slender and is adapted to be elastically strained when the stopping means is stopping the valve plug

Methodology Applied
Scientific EffectElastic strain: Elasticity

Implementation Method 2

said valve stem being long and slender and is adapted to be elastically strained when the stopping means is stopping the valve plug, said valve stem being accelerated back in return by inherent tension spring properties of the valve stem

Methodology Applied
Scientific EffectInherent tension spring properties: Spring

Implementation Method 3

a piston that is caused to move to and from under the action of a hydraulic fluid under pressure

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 4

under the action of a hydraulic fluid under pressure

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP2744966B1High frequency fluid driven drill hammer percussion drilling in hard formations
Publication Date: 2019.10.02 HAMMERGY
  • EP2744966B1 patent drawingFigure 1
  • EP2744966B1 patent drawingFigure 2A~2D
  • EP2744966B1 patent drawingFigure 3A~3I

AI summary

A fluid pressure driven, high frequency percussion hammer for drilling in hard formations is presented. The hammer piston (20) of the percussion hammer has a relatively large and longitudinally extending bore (41 ) that provides minimal flow resistance for a drilling fluid flowing through the bore (41 ) during the return stroke of the hammer piston (20). The bore (41 ) is closeable in the upstream direction by a valve plug (23) that follows the hammer piston (20) during the stroke. The valve plug (23) is controlled by a relatively long and slender valve stem (49) that is mechanically able to stop the valve plug (23) by approximately 75 % of the full stroke length of the hammer piston (20) and separates the plug (23) from a seat ring (40). Thus the bore (41 ) opens up such that the bore fluid can flow there trough, and the inherent tension spring properties of the valve stem (49) returns the valve plug (23) so rapid that it will be good through flow during return of the hammer piston (20).