Jet Pump Spool Valve for Header Tank Vapor Venting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aircraft fuel systems face issues with vapor bubbles forming in the header tank due to low pressures and high temperatures, leading to cavitation and premature wear of the fuel pump, and existing solutions either restrict flow or increase system weight and complexity by requiring separate bypass lines.
Innovation Solution
An integrated jet valve with a spool and jet pump is used, where the jet pump is coupled to the fuel pump via a bleed line, allowing the spool to move between open and closed positions to control fluid paths, eliminating the need for a separate bypass line and enhancing pressure in the header tank to vent vapor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate bypass line is used to prevent cavitation, then vapor can be vented from the header tank, but the system weight and complexity increase
Solution Approach 1:
The patent combines the bypass line functionality into the main fuel line by integrating a spool valve assembly directly onto the fuel pump. This integration eliminates the need for a separate bypass line while maintaining the vapor venting capability, thereby reducing system complexity and weight while preventing cavitation
2Reliability
If a separate bypass line is used to prevent cavitation, then vapor can be vented from the header tank, but the system weight increases
Solution Approach 1:
The bypass functionality is merged with the main fuel line through the integrated spool valve assembly on the fuel pump. This eliminates the need for additional separate bypass line components, reducing overall system weight while maintaining effective vapor venting and cavitation prevention
3Reliability
If the spool is in the closed position to vent vapor, then cavitation is prevented, but fuel flow restriction occurs
Solution Approach 1:
The spool valve is designed to be dynamic, automatically transitioning between open and closed positions based on real-time pressure conditions in the header tank. When vapor pressure builds up, the spool closes to vent vapor and prevent cavitation. When normal operation resumes, the spool opens to restore full fuel flow. This dynamic response ensures both cavitation prevention and maintained productivity
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 prevents cavitation, allows efficient fueling and defueling without flow restrictions, and reduces the weight and complexity of the fuel system by eliminating the need for a separate bypass line.
Implementation Method 1
a jet pump is fluidly coupled to a fuel pump of the header tank via a bleed line. The jet pump is disposed within the aperture, where operation of the fuel pump pressurizes the bleed line and moves the spool to a first position
Data Source
AI summary
A jet valve includes a valve body, a juncture operatively coupled to the valve body. The juncture having a first fluid connection fluidly coupled to a header tank and a second connection fluidly coupled to a storage tank. A spool is movably disposed within the valve body. A jet pump is fluidly coupled to a fuel pump of the header tank via a bleed line. Operation of the fuel pump pressurizes the bleed line and moves the spool to a first position to (i) close a first fluid path between the header tank and the storage tank and (ii) provide a second fluid path between the header tank and the storage tank, the second fluid path through the aperture. Depressurization of the bleed line enables the spring to move the spool to a second position to close the second fluid path and open the first fluid path.