Integral Pump Pressure Relief Valve Design
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Solution Overview
Problem
Conventional pressure relief systems in cartridge/canister fuel pumps require extra plumbing to route discharge flow back to the impeller inlet, increasing size, weight, and complexity, which negatively affects fuel efficiency and performance, especially in aircraft systems.
Innovation Solution
An integral pressure relief valve within the cartridge assembly directs discharge flow from the downstream impeller directly to the upstream inlet, eliminating the need for external plumbing and reducing the distance for discharge flow, using a movable element biased by an elastic element to open and relieve excess pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an external pressure relief valve with extended plumbing is used, then pressure relief function is achieved, but size, weight, and complexity increase
Solution Approach 1:
The pressure relief valve is integrated directly into the cartridge assembly, merging the pressure relief function with the existing pump structure. This eliminates the need for separate external plumbing and valves, thereby reducing device complexity while maintaining the pressure relief function.
Solution Approach 2:
The pressure relief function is extracted from the external plumbing system and incorporated directly into the cartridge assembly. This removes the need for extended plumbing external to the cartridge, reducing overall system complexity and weight.
2Reliability
If an external pressure relief valve with extended plumbing is used, then pressure relief function is achieved, but weight increases
Solution Approach 1:
The pressure relief valve is merged with the cartridge assembly, eliminating separate external components and their associated weight. The integrated design uses the existing cartridge structure to house the pressure relief function, thereby reducing overall pump assembly weight.
Solution Approach 2:
The external plumbing and separate pressure relief valve are removed from the system. The pressure relief function is taken out of the external plumbing domain and incorporated into the cartridge, eliminating the weight of extended plumbing and external valve components.
3Reliability
If discharge flow travels a substantial distance through extra plumbing, then pressure relief is achieved, but fuel efficiency and performance decrease
Solution Approach 1:
The pressure relief valve is positioned within the cartridge assembly, merging the pressure relief function with the pump's core structure. This eliminates long discharge flow paths through external plumbing, reducing energy losses and improving fuel efficiency.
Solution Approach 2:
The extended external plumbing pathway is removed from the system. The discharge flow path is shortened by incorporating the pressure relief valve directly into the cartridge, thereby reducing the distance discharge flow must travel and minimizing energy losses.
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 configuration reduces weight, complexity, and the potential for external leakage, while minimizing pressure pulsations and maintaining efficient fuel flow by directly routing discharge flow back to the impeller inlet, enhancing reliability and performance.
Implementation Method 1
The pressure relief valve includes a movable element that is biased by an elastic element that allows the valve to open when the discharge pressure is too high or above a predetermined threshold
Implementation Method 2
Fuel tank mounted fuel pumps generally utilize centrifugal pumping elements which typically are either radial or mixed flow type impellers
Data Source
AI summary
A fuel pump includes a cartridge removably received within a canister. The cartridge includes a motor assembly, and a pump assembly that includes a centrifugal pumping element and outlet porting from the centrifugal pumping element. The motor drives the centrifugal pumping element to generate a flow of fluid through a main flow pathway between a pump inlet and outlet through the outlet porting of the pump assembly. The cartridge further includes a pressure relief valve that is movable between a closed position and an open position, and defines a pressure relief flow pathway integrally within the cartridge from the outlet porting to inlet porting of the centrifugal pumping element. When pressure within the pump assembly exceeds a threshold pressure, the pressure relief valve moves from the closed position to the open position to permit a relief flow of fluid through the relief flow pathway. The fuel pump may be employed as part of an aircraft fuel system.