Emergency Actuator Control Bypassing Proportional Valves
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Solution Overview
Problem
Conventional systems for controlling hydraulic actuators in gas turbines face challenges in maintaining safe operational conditions during failures, such as sensor malfunctions or proportional valve failures, leading to potential engine damage due to incorrect positioning and rotation stalls.
Innovation Solution
A device with an emergency operation cycle that includes solenoid valves and hydraulically operated switch valves to bypass the proportional valve, allowing immediate switching to a safe predefined position, thereby preventing damage to engine components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a proportional valve with control electronics and sensors is used for normal operation, then positioning precision is improved, but reliability deteriorates due to potential failures of control electronics or sensors
Solution Approach 1:
The control system is segmented into a normal operation mode (proportional valve with control electronics) and an emergency operation mode (direct hydraulic control via solenoid valves). This segmentation allows the system to switch to a simpler, more reliable configuration when failures occur, resolving the contradiction between positioning precision and reliability.
Solution Approach 2:
The system changes its operational parameters by switching from proportional control (requiring precise electronic control and sensor feedback) to on/off control (using solenoid valves that directly open or close hydraulic passages). This parameter change enables the system to maintain reliability while sacrificing some positioning precision during emergency operations.
2Reliability
If the normal control system is blocked due to sensor failures or false measurements, then reliability is improved by preventing incorrect operation, but productivity deteriorates due to engine trip and coast down
Solution Approach 1:
The emergency operation cycle is prepared in advance with solenoid valves and hydraulic passages configured to directly position the actuator. When sensor failures or false measurements are detected, the system can immediately switch to this pre-prepared emergency mode, maintaining reliability while avoiding engine trip and preserving productivity.
3Reliability
If an emergency cycle with solenoid valves and switch valves is added, then reliability is improved by providing backup control, but device complexity increases
Solution Approach 1:
The emergency control function is extracted as a separate, independent cycle with its own solenoid valves and hydraulic passages. This extracted emergency cycle operates independently from the normal proportional control system, adding reliability through redundancy while managing complexity by keeping the emergency path separate and modular.
4Reliability
If the proportional valve is bypassed in emergency situations, then reliability is improved by eliminating the failure point, but manufacturing precision requirements increase for the bypass hydraulic passages
Solution Approach 1:
The bypass hydraulic passages are designed as simple, robust features that prioritize reliability over manufacturing precision. The solenoid valves and switch valves create direct hydraulic connections that are intentionally simpler than the proportional valve system, accepting relaxed manufacturing tolerances in exchange for eliminating the complex proportional control system during emergency 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 emergency operation mode effectively prevents engine component damage by ensuring safe positioning of hydraulic actuators, even in the presence of system failures, through a combined electronic and hydraulic safety backup system.
Implementation Method 1
two solenoid valves (2, 12) for initiating an emergency operation impulse
Implementation Method 2
a plurality of hydraulically operated switch valves (3, 13), which can be activated through the impulse of an emergency signal from the solenoid valves
Data Source
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AI summary
Device for emergency operation of pneumatic or hydraulic actuators (10), which have for normal operation of the actuator (10) an operation cycle including at least a proportional valve (1) for switching to different operational conditions of said actuator (10) and related engine components, the proportional valve (1) being arranged in a supply line (6) of pressurized liquid/gas and in a drain line (7) connected to a tank, and control means for operation control and supervising functions, whereby an emergency cycle is attached to said operation cycle of said actuator (10) which is provided with: at least one solenoid valve (2, 12) for initiating an emergency operation impulse in case of detected failures; a plurality of pneumatically/hydraulically operated switch valves (3, 13; 4, 14; 5, 15) which may be activated through said impulse of an emergency signal from said solenoid valve (2, 12); and whereby the emergency cycle is adapted to bypass said proportional valve (1) in emergency situations and to either block said actuator (10) in its actual position or to bring said actuator (10) in a predefined safe position.