Hydraulic Crowd System Single-Direction Flow Mining Shovel
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Solution Overview
Problem
Existing hydraulic crowd mechanisms for mining shovels require complex and maintenance-intensive large hoses to manage high-pressure hydraulic fluid, which are prone to wear and failure.
Innovation Solution
A hydraulic crowd mechanism utilizing a double-acting hydraulic cylinder with a cylinder control manifold that directs fluid flow in a single direction, featuring a smaller high-pressure supply conduit and larger low-pressure return conduit, eliminating the need for flexible hoses and reducing maintenance through a fixed displacement pump driven by a variable speed motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large hoses are used to carry high-volume hydraulic fluid at high pressures, then the hydraulic system can control the crowd mechanism, but the hoses are subject to significant wear and require significant maintenance
Solution Approach 1:
The patent replaces the mechanical hose system with a rigid piping system. The rigid pipes eliminate the wear and maintenance issues associated with flexible hoses while maintaining the same hydraulic fluid transport function. This substitution of mechanical components resolves the contradiction between reliability and device complexity.
Solution Approach 2:
The patent changes the flow parameters by using a smaller diameter supply line for high-pressure fluid delivery and a larger diameter return line for low-pressure fluid return. This parameter optimization allows the system to achieve the same hydraulic control function with reduced stress on the high-pressure components, improving durability while maintaining system performance.
2Reliability
If a smaller supply conduit is used for high pressure supply, then hose wear is reduced, but fluid flow volume must be optimized
Solution Approach 1:
The patent optimizes the conduit dimensions by using a smaller diameter for the high-pressure supply line and a larger diameter for the low-pressure return line. This parameter change allows the supply line to withstand high pressure with reduced wear while the return line accommodates higher flow volumes at lower pressure, resolving the contradiction between durability and flow efficiency.
Solution Approach 2:
The patent applies different dimensional characteristics to different parts of the hydraulic system - the supply line is designed with smaller diameter and higher pressure tolerance for durability, while the return line is designed with larger diameter for optimal flow return. This local optimization of component properties resolves the contradiction between reliability and productivity.
3Speed
If a fixed displacement pump is used with variable speed motor, then response to operator inputs is quick, but energy consumption varies
Solution Approach 1:
The patent combines a fixed displacement pump with a variable speed motor, creating a dynamic system where the motor speed can be adjusted to match the actual hydraulic demand. This allows the system to respond quickly to operator inputs when needed while consuming less energy during low-demand operations, resolving the contradiction between speed and energy consumption.
Solution Approach 2:
The variable speed motor provides feedback-based speed adjustment to match the hydraulic system's actual needs. The control system monitors operational requirements and adjusts motor speed accordingly, ensuring quick response when rapid action is needed while reducing energy consumption during normal or low-demand operations.
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 provides a robust and low-maintenance hydraulic system that responds quickly to operator inputs, reduces hose wear, and maintains equal extend and retract speeds, improving the reliability and efficiency of the mining shovel's crowd mechanism.
Implementation Method 1
a pump in the hydraulic power unit pressurizes hydraulic fluid in a single direction from a supply tank
Implementation Method 2
a double acting hydraulic cylinder for extending and retracting the dipper handle horizontally
Data Source
AI summary
A mining shovel (10) includes a hydraulic system comprising a plurality of fixed displacement pumps (104,106,108,110) driven by a variable speed motor (100), and a tank (68) system comprising an upper return tank and a lower supply tank (70). A cylinder manifold (64) is connected to the pump control manifold (112), and includes a directional control valve for directing the extend and retract functions of the cylinder (50), while accepting fluid flow in a single direction from the pump control manifold. The single direction flow allows for the use of smaller fluid conduits (61), such that the hose providing a high pressure supply can be comparatively smaller than the return hose (67).