Modular Drill Head Steering for Microtunneling Precision

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Solution Overview

Problem

Current microtunnelling technologies are cumbersome, inaccurate, and prone to component breakage due to excessive strain on elongated drive shafts, and they require repeated halting for waste removal and heating effects, leading to inefficiencies and safety concerns during underground boring operations.

Innovation Solution

The implementation of an external casing with flow channels for cabling, a vacuum chamber for heat removal and increased productivity, a radially protruding steering mechanism to prevent undue force on the drill head, and a modular drill head design with interchangeable rotational units for push and pull capabilities, allowing for precise directional control and versatile pipe installations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If horizontal directional drilling is used to bore underground holes, then the method overcomes disruption to roads and infrastructure, but the steering mechanism is extremely inaccurate and unsuitable for applications on grade

Engineering Contradiction:
Improvedisruption to roads and infrastructureVSAvoidsteering accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical steering mechanism of conventional HDD with a laser-guided system. A laser beam provides a precise visual reference for the operator to follow, eliminating reliance on imprecise mechanical steering components. The laser target mounted on the drill head allows the operator to accurately maintain the bore path on grade by visually aligning with the laser beam rather than relying on mechanical steering adjustments.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If pilot displacement method is used with short drill strings, then the method can adapt to ground conditions, but the time to drill is slow with repeated connections

Engineering Contradiction:
Improveadaptation to ground conditionsVSAvoiddrilling speed
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent enables continuous drilling operations by eliminating the need for repeated drill string connections. The extended drill string design allows the drill head to reach greater depths without requiring frequent stoppage for connection adjustments. This maintains continuous drilling action, significantly improving productivity while preserving the ability to adapt to varying ground conditions through the extended reach capability.

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If slurry style microtunnelling is used to transport spoil removal, then the system achieves good degree of accuracy, but requires a structural shaft that needs a massive amount of force to push the pipes

Engineering Contradiction:
Improveboring accuracyVSAvoidjacking force required
Core Design Contradiction:
Measurement precisionVSForce

Solution Approach 1:

The patent extracts the drill head and drill string from the conventional slurry microtunnelling system that requires massive jacking forces. By using a drill string that can be rotated and advanced through the ground, the system eliminates the need for structural shafts and high-force jacking mechanisms. The drill string itself becomes the conduit for both drilling and spoil removal operations, significantly reducing the force requirements while maintaining accurate bore positioning.

Inventive Principle:
Principle #2Taking out (Extraction)

4Length of moving object

If elongated drive shafts are used in microtunnelling systems, then the system can reach greater depths, but the components are prone to breakage due to excessive strain

Engineering Contradiction:
Improvedrive shaft lengthVSAvoidcomponent durability
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent transitions from static, strain-prone elongated drive shafts to a dynamic system where the drill string can be rotated. This rotation distributes mechanical stresses more evenly along the string length and prevents the concentration of strain that leads to breakage. The modular drill string design allows for flexible configuration that maintains reliability while achieving greater drilling depths through controlled rotational mechanics rather than relying solely on elongated static shafts.

Inventive Principle:
Principle #15Dynamics

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 solution enhances the accuracy and reliability of underground boring by maintaining laser precision, reducing the risk of drill head component breakage, and enabling continuous operation with automated steering and modular components that adapt to varying ground conditions and pipe sizes, improving safety and efficiency.

Implementation Method 1

a vacuum chamber for heat removal and increased productivity

Methodology Applied
Scientific EffectVacuum cooling: Vacuum

Implementation Method 2

an external casing with flow channels for cabling

Methodology Applied
Scientific EffectFluid flow heat transfer: Convection

Data Source

PatentEP2824274B1Microtunneling system and apparatus
Publication Date: 2018.01.31 VERMEER MFG CO
  • EP2824274B1 patent drawingFigure 1
  • EP2824274B1 patent drawingFigure 2
  • EP2824274B1 patent drawingFigure 3

AI summary

A microtunnelling apparatus and system that includes an external drive system having rotational and linear thrust drive means, a drill head section (20) having drill rotor (21) and drill rod (22) and connecting to intermediate drill rods (41) allowing extension of the boring hole created by the drill head section drive system. The drill head (20) includes a modular construction having a plurality of circular disc like elements, a bearing module M1, a steering module M2, a spacer module M3, and a mounting module M4, for axial alignment and abutment and mounting within a cylindrical steering shell M6. Directional steering of the drill head (20) includes a plurality of substantially radially extending channels in steering module M2, each with an hydraulically movable protuberance movable by control means to redirect the outer steering casing M6 and thereby redirect the drill head section mounted on the distal end of the drill rods.