Sleeve-like Piston Fluid Routing for DTH Drilling

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Solution Overview

Problem

Existing down-the-hole (DTH) drilling machines have inefficient impact devices due to fluid routing systems that limit the size of working areas and require external passages, which restrict the effectiveness of impact pulses and increase the outer dimensions of the device.

Innovation Solution

A sleeve-like piston with a longitudinal central opening for fluid passages inside the piston, allowing for maximized working chamber areas and robust structure, enabling greater impact pulses without increasing the device's outer dimensions, and eliminating the need for external control elements by using a double feed tube structure for fluid control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If fluid passages are arranged outside the piston, then fluid routing is simplified, but the working areas of the piston are limited and outer dimensions increase

Engineering Contradiction:
Improveworking area of pistonVSAvoidfluid routing structure
Core Design Contradiction:
Area of moving objectVSDevice complexity

Solution Approach 1:

The fluid passages are nested inside the central opening of the piston, with feed tubes positioned within the piston's bore. This nesting arrangement allows fluid routing components to occupy the internal space of the piston rather than external space, thereby maximizing the piston's working area while containing all necessary fluid control elements within a compact configuration.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention transitions from external fluid passages to internal fluid passages by utilizing the axial dimension of the piston's central opening. Feed tubes extend axially through the piston bore, and fluid control is achieved through axial positioning and radial openings that communicate with the working chambers, effectively using the piston's internal volume for fluid routing.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If control sleeves or valves are added for fluid discharge control, then fluid flow control is improved, but structural complexity increases

Engineering Contradiction:
Improvefluid flow controlVSAvoidcontrol elements
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The piston itself serves as the control element for fluid discharge. As the piston reciprocates, its position automatically controls the opening and closing of discharge passages without requiring separate control sleeves or valves. The piston's own movement regulates fluid flow between the working chambers and the discharge system, eliminating the need for additional control components.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The piston performs multiple functions: it generates impact force, routes fluid to working chambers, and controls fluid discharge. By integrating these functions into a single component, the invention eliminates the need for separate control elements, reducing structural complexity while maintaining full fluid control capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Strength

If the piston is made solid without transverse openings, then structural robustness is improved, but fluid routing becomes more complex

Engineering Contradiction:
Improvepiston structureVSAvoidfluid passages configuration
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The fluid routing system is nested within the solid piston structure. Feed tubes are positioned inside the piston's central opening, and fluid passages are formed within the piston bore rather than through transverse openings in the piston wall. This maintains the solid, robust piston structure while incorporating all necessary fluid routing elements internally.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 configuration enhances the effectiveness of the impact device by increasing impact pulse size and maintaining a compact structure, ensuring efficient fluid routing and pneumatic expansion, and simplifying the structure by eliminating the need for separate control elements.

Implementation Method 1

when the drilling machine is pneumatically operated this solution also ensures as great space as possible for the supplied air and its pneumatic expansion during the work cycle

Methodology Applied
Scientific EffectPneumatic expansion: Pressure Increase

Data Source

PatentEP3409879B1Down the hole drilling machine and method for drilling rock
Publication Date: 2019.11.20 SANDVIK INTELLECTUAL PROPERTY AB
  • EP3409879B1 patent drawingFigure 1~2
  • EP3409879B1 patent drawingFigure 3~4
  • EP3409879B1 patent drawingFigure 5

AI summary

A down the hole rock drilling machine and a method of drilling rock. The drilling machine comprises a reciprocating piston (19), which has sleeve-like configuration. Inside a central opening (20) of the piston is arranged one or more fluid passages for conveying pressurized fluid during work cycle of an impact device of the drill machine.