Electro-Hydraulic Pump and Valve Coordination for Precise Flow Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hydraulic systems in industrial applications face inefficiencies due to the inability to precisely control fluid flow and pressure, leading to increased energy consumption and reliability issues, particularly because of the complexity and open-loop nature of these systems, which can result in pump cavitation and machine downtime.
Innovation Solution
A hydraulic system incorporating a variable-speed and/or variable-torque pump with proportional control valves and a controller that synchronizes the operation of the pump and control valves to achieve faster and more precise control of fluid flow and pressure, reducing the risk of cavitation and allowing for smaller accumulator sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a conventional hydraulic pump runs at full speed or constant speed to ensure adequate pressure, then the system maintains required pressure for flow control devices, but energy efficiency deteriorates as the pump runs at full speed even when system load is only at 50%
Solution Approach 1:
The patent applies variable speed drive technology to the hydraulic pump, allowing the pump speed to dynamically adjust according to actual system load requirements. The controller receives feedback from sensors and modulates the motor speed accordingly, enabling the pump to operate at optimal speeds rather than constant full speed, thus resolving the contradiction between maintaining adequate pressure and reducing energy consumption.
Solution Approach 2:
The system incorporates sensors that monitor system pressure, flow rate, and motor parameters, feeding this information back to the controller. The controller uses this feedback to continuously adjust pump speed and torque, ensuring pressure requirements are met while minimizing energy consumption. This closed-loop control resolves the contradiction by making pump operation responsive to actual system needs.
2Use of energy by moving object
If the hydraulic pump speed is varied to control flow precisely, then energy efficiency improves, but the inertia of the hydraulic pump makes it impractical to vary speed for precise flow control
Solution Approach 1:
The patent introduces proportional control valves as intermediary devices between the pump and the hydraulic actuators. These valves provide precise flow control by modulating fluid passage, compensating for the pump's inertia and inability to respond quickly to speed changes. The combination of variable speed pump and proportional valves allows both energy efficiency and responsive control to be achieved.
Solution Approach 2:
The system uses dynamic coordination between variable speed pump operation and proportional valve positioning. The controller adjusts both pump speed and valve opening in real-time based on feedback signals, enabling precise flow control despite the pump's inertial characteristics. This dynamic coordination resolves the contradiction between energy-efficient variable speed operation and responsive flow control.
3Measurement precision
If flow control devices are added to control flow in the system, then flow control precision improves, but system complexity increases and additional hydraulic fluid is required for hydraulic controls
Solution Approach 1:
The patent replaces traditional hydraulic control mechanisms with an electro-hydraulic control system. The proportional control valves are actuated by electric motors rather than hydraulic pressure, eliminating the need for separate hydraulic control circuits and additional hydraulic fluid. This substitution maintains precise flow control capability while reducing system complexity and eliminating the need for additional hydraulic fluid reserves.
4Reliability
If an open-loop hydraulic system with a large fluid reservoir is used, then the system can maintain fluid temperature and prevent cavitation, but the system requires additional connecting components that are susceptible to contamination and damage
Solution Approach 1:
The patent merges the pump, motor, and control valves into a more integrated configuration, reducing the need for extensive external connecting components. The variable speed pump with integrated control electronics and the proportional valves are arranged to minimize external piping and fittings. This integration maintains cavitation prevention capabilities through controlled fluid management while reducing the number of external components susceptible to contamination and damage.
Solution Approach 2:
The closed-loop control system with sensors monitoring pressure, flow, and motor parameters enables the system to maintain adequate fluid pressure and flow conditions that prevent cavitation without requiring a large external reservoir. The feedback control ensures fluid is always available to the pump inlet at sufficient pressure, eliminating the need for extensive connecting components and large reservoirs while maintaining reliability.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A fluid system includes a variable-speed and/or a variable-torque pump to pump a fluid, at least one proportional control valve assembly, an actuator that is operated by the fluid to control a load, and a controller that establishes a speed and/or torque of the pump and a position of the at least one proportional control valve assembly. The pump includes at least one fluid driver that provides fluid to the actuator, which can be, e.g., a fluid-actuated cylinder, a fluid-driven motor or another type of fluid-driven actuator that controls a load. Each fluid driver includes a prime mover and a fluid displacement assembly. The fluid displacement assembly can be driven by the prime mover such that fluid is transferred from the inlet port to the outlet port of the pump.