Air Purging Pressure Regulating Valve for Stable Damping
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Solution Overview
Problem
Entrained air in damping chambers of pressure regulating valves reduces the damping effect, leading to unstable pressure regulation in generator systems, particularly in aircraft, where varying oil pump speeds cause unduly high or low pressures.
Innovation Solution
The pressure regulating valve incorporates damper chambers with a damper supply line that uses check valves and orifices to purge air outwardly, ensuring the oil in these chambers is relatively air-free, thereby maintaining stable pressure regulation by controlling the spool movement speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air is entrained in the damping chambers, then the damping effect is reduced, but the structure remains simple
Solution Approach 1:
The valve is divided into functional segments: a damping chamber section with purging means separate from the main pressure regulating section. This segmentation allows the damping chamber to be independently purged of air while maintaining the overall valve structure, resolving the contradiction by improving damping reliability through structural division without excessive complexity increase.
Solution Approach 2:
A purging means (intermediary mechanism) is introduced into the damping chamber to actively remove entrained air. This intermediary component facilitates air removal through check valves and communication passages, thereby restoring and maintaining the damping effect without requiring complete redesign of the valve structure.
2Speed
If the spool moves quickly to regulate pressure, then the response time is improved, but the damping effect becomes unstable
Solution Approach 1:
The damping chamber is pre-filled with air-free oil through the purging means before normal operation begins. This preliminary action ensures that the damping medium is properly prepared, allowing the spool to move quickly for rapid pressure regulation while maintaining stable damping effects throughout operation, as the damping chamber starts in an optimal state.
Solution Approach 2:
The damping chamber with purging means creates a feedback mechanism where air is continuously removed and the damping effect is maintained. This feedback ensures that even as the spool moves quickly to regulate pressure changes, the damping chamber maintains its stabilizing influence, preventing oscillations and ensuring stable pressure regulation.
3Reliability
If check valves are added to purge air, then air removal capability is improved, but the device complexity increases
Solution Approach 1:
The purging function is merged with the existing damping chamber structure rather than being implemented as a completely separate system. The check valves are integrated into the damping chamber assembly, and the communication passages utilize existing valve body pathways. This merging approach improves air removal capability while minimizing the increase in overall device complexity by leveraging existing structural elements.
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
This solution effectively prevents air entrainment, maintaining stable dynamic performance and preventing unduly high or low pressures from reaching downstream locations, ensuring consistent oil flow and lubrication in generator systems.
Implementation Method 1
A damper supply line supplies fluid into the damper chambers through check valves
Implementation Method 2
The damping action is typically provided by oil in the chambers moving through orifices
Implementation Method 3
The spool is biased in one direction by a spring force
Data Source
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AI summary
A valve housing receives a spool 34 and the spool has a regulating chamber 52 selectively communicating a supply line to a return line. The spool 34 is biased in one direction by a spring force and there is a second force biasing the spool in an opposed direction whith the second bias force being provided by a fluid pressure within a hydraulic system associated which the pressure regulating valve. The amount of communication between the supply port 111 and the return port 99 is regulated by a position of the spool 34 as the bias force from the fluid pressure change. Damper chambers are provided on opposed sides of the spool and serve to dampen a speed of movement of the spool and a supply line for supplying fluid into the damper chambers through check valves 44, 64. The supply line serves to assist in purging air outwardly of the damper chambers.