Hydromill Wheel Single Disc Cutters Hard Rock Excavation
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Solution Overview
Problem
Conventional hydromill systems face inefficiencies when excavating hard or very hard rock, as existing teeth or drag bits become ineffective, requiring frequent chiselling and vibration-limited processes, which are slow and often prohibited in sensitive environments.
Innovation Solution
The use of single disc cutters with a small surface area, spaced 5% to 70% of the disc diameter, mounted on the periphery of a rotating drum, allowing for high crushing forces and efficient fracture creation in hard rock, with even distribution around the wheel circumference to minimize contact and maximize chip size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If teeth or drag bits are used on hydromill wheels, then excavation in soft ground is effective, but excavation in hard or very hard rock becomes inefficient and requires frequent chiselling
Solution Approach 1:
The invention changes the fundamental parameter of the cutting element geometry from teeth/drag bits to single disc cutters. This parameter change enables the cutting elements to effectively fracture hard rock while maintaining continuous operation, eliminating the need for frequent chiselling and thereby improving both productivity and reliability in hard rock excavation.
Solution Approach 2:
The cutting wheel is segmented into multiple individual single disc cutters spaced around its circumference. This segmentation allows each disc to independently engage and fracture rock, providing continuous cutting action as the wheel rotates, thus maintaining reliable continuous operation in hard rock conditions.
2Strength
If rollers with button bits are used instead of teeth, then rock crushing capability is improved, but insufficient pressure is applied due to limited cutter system weight
Solution Approach 1:
The single disc cutters are designed with a localized sharp edge that concentrates the cutting force onto a very small area of the rock. This local quality enhancement allows the disc to generate extremely high contact pressure at the cutting point, effectively overcoming the limitation of insufficient overall system weight and enabling effective rock crushing.
3Force
If single disc cutters with small surface area are used, then huge crushing forces are obtained, but the spacing and distribution of discs must be optimized to ensure efficient rock fracture
Solution Approach 1:
The single disc cutters are pre-positioned and spaced around the drum circumference during manufacturing and installation. This preliminary arrangement ensures that as the drum rotates, discs are systematically distributed to create overlapping fracture patterns in the rock, optimizing the crushing action without requiring complex real-time adjustment mechanisms.
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
Enables efficient trench excavation in rock with strengths exceeding 150 MN/m2 by creating larger rock chips and applying immense pressure with fewer discs in contact, reducing the need for chiselling and minimizing environmental impact.
Implementation Method 1
the single disc cutters can be distributed, evenly if necessary, all around the circumference of the wheels, which has a further advantage that only a few of the discs are in contact with the rock at any given time... the rock chips are created between the traces of the discs, by creating fractures in the rock
Data Source
AI summary
A hydromill wheel (5) for excavating a trench in hard rock includes a drum (4) arranged to be rotated about its axis (A, B). The wheel (4) further includes a plurality of single disc cutters (11) mounted on the periphery of the drum (5), the single disc cutter (11) having a rotatable single cutting disc (11) arranged to come in contact with and crush the rock during excavation. The spacing of the projection of at least some of the cutting discs (11) on the drum axis (A, B) is 20% to 70% of the cutting disc diameter.