Percussive Fluid Flow System Asymmetric Feeding
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Solution Overview
Problem
Existing pressurized fluid flow systems for DTH hammers face issues such as cylinder deformation under high pressure, reduced piston thrust areas, and fatigue due to galling, limiting the operational pressure and reliability of the drilling process.
Innovation Solution
A pressurized fluid flow system with a thinner cylinder design and a valve system that allows for asymmetric feeding of the rear chamber, enabling increased piston thrust areas and improved energy conversion efficiency, while maintaining the piston's reversibility and reducing friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a traditional thick cylinder design is used to withstand high pressure, then the structural strength is improved, but the piston thrust area is reduced and manufacturing cost increases
Solution Approach 1:
The cylinder is divided into multiple segments or sections, each optimized for specific pressure zones. This allows the cylinder to withstand high pressure without requiring excessive thickness throughout, thereby preserving piston thrust area while maintaining structural integrity.
Solution Approach 2:
The cylinder wall thickness is optimized by changing the material parameters and structural configuration. By using high-strength materials and optimized thickness parameters, the cylinder can withstand high pressure with reduced thickness, increasing the piston thrust area.
2Reliability
If a thick cylinder design is used to prevent deformation, then the reliability is improved, but the manufacturing cost increases
Solution Approach 1:
By changing the material parameters and structural configuration of the cylinder, the design achieves high reliability with reduced material usage. The optimized parameters allow for cost-effective manufacturing while maintaining the necessary strength and deformation resistance.
3Device complexity
If symmetric feeding is used in the pressurized fluid system, then the system simplicity is maintained, but the energy conversion efficiency is reduced
Solution Approach 1:
The feed system is designed with asymmetric characteristics where the feeding parameters (pressure, flow rate, timing) differ between the ascending and descending strokes of the piston. This asymmetry optimizes energy conversion efficiency by matching the fluid feeding to the actual work requirements of each stroke phase.
Solution Approach 2:
The feeding system transitions from a static symmetric design to a dynamic asymmetric design that adapts to the changing pressure and flow requirements during different phases of the piston cycle. This dynamic adjustment improves energy efficiency while maintaining reasonable system complexity.
4Power
If high operational pressure is used to increase power, then the drilling performance is improved, but the cylinder deformation and fatigue increase
Solution Approach 1:
By optimizing the cylinder material parameters and structural configuration, the system can operate at high pressures to deliver high drilling power while preventing excessive deformation and fatigue. The parameter optimization allows the cylinder to withstand high operational pressures reliably.
Data Source
AI summary
A pressurized fluid flow system for percussive mechanisms comprises a cylinder coaxially disposed in between an outer casing and a piston which reciprocates due to the changes in pressure of the pressurized fluid contained inside a front chamber and rear chamber located at opposites sides of the piston. The discharge of fluid from these chambers being conducted through a set of discharge channels and the supply of fluid to the front chamber being conducted through a set of supply channels and a front set of recesses. The supply of fluid to the rear chamber being conducted through a piloted valve.