Passive Bleed Valve With Adjustable Differential Pressure Threshold
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Solution Overview
Problem
Conventional bleed valves in gas turbine engines require active control mechanisms, which add complexity, mass, and size, and do not efficiently manage fluid flow during engine starting when power from combustion products is limited.
Innovation Solution
A passively controlled inline bleed valve design featuring a housing with a duct, guide tube, piston, and baffle, where the piston moves between open and closed positions based on differential pressure, and a set pin mechanism adjusts the differential pressure threshold, allowing fluid communication between the inlet and outlet without active solenoid control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active control mechanisms (solenoid) are used to open and close the bleed valve, then the valve can be precisely controlled, but the complexity, mass, and size of the valve increase
Solution Approach 1:
The bleed valve utilizes the differential pressure between the compressor inlet and outlet to automatically control the piston position. The system serves itself by using the process fluid's own pressure characteristics to actuate the valve, eliminating the need for external solenoid control mechanisms.
Solution Approach 2:
The patent replaces the electromagnetic solenoid control system with a passive mechanical system. The piston is actuated purely by differential pressure forces acting on it, converting an active electromagnetic control system into a passive mechanical response system that reduces complexity and mass.
2Reliability
If active control mechanisms (solenoid) are used to open and close the bleed valve, then the valve can be precisely controlled, but the mass and size of the valve increase
Solution Approach 1:
The bleed valve utilizes the differential pressure between the compressor inlet and outlet to automatically control the piston position. The system serves itself by using the process fluid's own pressure characteristics to actuate the valve, eliminating the need for external solenoid control mechanisms.
Solution Approach 2:
The patent replaces the electromagnetic solenoid control system with a passive mechanical system. The piston is actuated purely by differential pressure forces acting on it, converting an active electromagnetic control system into a passive mechanical response system that reduces complexity and mass.
3Device complexity
If the bleed valve uses passive operation based on differential pressure, then the complexity and size are reduced, but the ability to actively control valve operation is limited
Solution Approach 1:
The baffle position is made adjustable rather than fixed, allowing the differential pressure threshold for valve actuation to be dynamically changed. This enables the same passive valve design to adapt to different operating conditions and compressor requirements without sacrificing the simplicity of passive operation.
Solution Approach 2:
The patent allows modification of the differential pressure threshold by adjusting the baffle position, which changes the effective area on which pressure acts. This parameter adjustment provides control flexibility while maintaining the passive operational simplicity of the valve design.
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 reduces the complexity and size of the bleed valve by utilizing passive operation, effectively managing fluid flow based on pressure differentials, enhancing reliability and reducing costs by eliminating the need for active control mechanisms.
Implementation Method 1
the piston is movable between an open and a closed position, the duct fluidly coupling the inlet and outlet in the open position, the duct fluidly separating the inlet and outlet in the closed position. The orifice fluidly couples the inlet and outlet in the open and closed positions to move piston between the open and closed positions according to differential pressure between the bleed valve inlet and outlet.
Implementation Method 2
The baffle is slideably supported by the guide tube to set the differential pressure at which the piston moves between the open and closed positions.
Implementation Method 3
A set pin can movably couple the baffle to the housing for displacement of the baffle relative to the guide tube. The set pin can be free for rotation and axial movement relative to the housing for setting the differential pressure.
Data Source
AI summary
A bleed valve includes a housing with an inlet coupled to an outlet by a duct, a guide tube with an orifice fixed in the housing between the inlet and the outlet, a piston, and baffle. The piston is slideably supported on the guide tube and is movable between an open and a closed position, the duct fluidly coupling the inlet and outlet in the open position, the duct fluidly separating the inlet and outlet in the closed position. The orifice fluidly couples the inlet and outlet in the open and closed positions to move piston between the open and closed positions according to differential pressure between the bleed valve inlet and outlet. The baffle is slideably supported by the guide tube to set the differential pressure at which the piston moves between the open and closed positions. Gas turbines and differential pressure adjustment methods are also described.