Counter Pressure Valve Arrangement for Return-Line Cavitation Control
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Solution Overview
Problem
Hydraulic systems face risks of cavitation in hydraulic actuators due to restricted fluid supply and low pressure conditions, particularly during float and regenerative operations, which existing technologies fail to adequately address.
Innovation Solution
A counter pressure valve arrangement with a moveable valve member, connecting the hydraulic actuator's return line to a tank and a pressurized fluid source, allowing for active refill and pressure relief by shifting between two positions to maintain optimal pressure levels, thereby reducing cavitation risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passive counter pressure functionality is used to maintain refill capacity, then the hydraulic system can prevent cavitation under normal conditions, but the counter pressure becomes too low during restricted fluid supply conditions
Solution Approach 1:
The patent combines a passive counter pressure functionality with an active refill functionality in a single valve arrangement. The counter pressure valve is integrated with a refill valve that can actively introduce pressurized hydraulic fluid into the return line when the counter pressure drops below a threshold level, thereby maintaining reliable cavitation prevention under all operating conditions including restricted fluid supply
Solution Approach 2:
The system incorporates a feedback mechanism where the actual counter pressure level is monitored and compared to a threshold value. When the counter pressure falls below the threshold, the refill valve is activated to introduce pressurized fluid, and when the pressure rises above the threshold, the refill valve closes. This closed-loop control ensures the counter pressure is maintained within the optimal range for cavitation prevention
2Reliability
If separate counter pressure valve and refill valve are used, then each function can be optimized independently, but the system complexity and cost increase
Solution Approach 1:
The patent merges the counter pressure valve and refill valve into a single integrated arrangement. The counter pressure valve maintains the baseline counter pressure in the return line, while the refill valve is integrated to provide active refilling when needed. This combination reduces the number of separate components, simplifies the system architecture, and lowers cost while maintaining effective cavitation prevention
Solution Approach 2:
The integrated valve arrangement performs multiple functions: it maintains counter pressure under normal conditions and actively refills the return line when pressure drops. This multi-functional design eliminates the need for separate dedicated components for each function, reducing overall system complexity while ensuring reliable operation across all operating scenarios
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 effectively merges counter pressure and active refill functionalities in a compact, cost-efficient design, reducing the risk of cavitation by automatically regulating pressure levels in the return line, ensuring reliable operation of hydraulic actuators.
Implementation Method 1
a first position of the valve member effects fluid communication between the pump port and the counter pressure regulating port for supplying pressurised hydraulic fluid to the return line; and wherein a second position of the valve member effects fluid communication between the counter pressure regulating port and the tank port for discharging hydraulic fluid from the return line to the tank
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5B
AI summary
A counter pressure valve arrangement (5) for controlling a pressure level of a hydraulic fluid in a return line (4) from a hydraulic actuator arrangement. The counter pressure valve arrangement (5) comprises a counter pressure valve (6) having: a moveable valve member (22); a counter pressure regulating port (7) configured for being connected to the hydraulic actuator arrangement via the return line (4); a tank port (8) configured for being connected to a tank (3) or low pressure reservoir for storing low pressure hydraulic fluid; and a pump port (10) configured for being connected to a source of pressurised hydraulic fluid (2, 11). A first position of the valve member (22) effects fluid communication between the pump port (10) and the counter pressure regulating port (7) for supplying pressurised hydraulic fluid to the return line (4), and a second position of the valve member (22) effects fluid communication between the counter pressure regulating port (7) and the tank port (8) for discharging hydraulic fluid from the return line (4) to the tank (3).