Pressure Relief Valve Assembly With Fluid-Submerged Spring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional pressure relief valves used in aircraft engine cowl maintenance are unreliable due to ice formation at cold temperatures, which alters the set point and can cause damage by opening at higher pressures than intended, especially during short stopovers when heating devices are not feasible.
Innovation Solution
A secondary valve assembly that keeps the primary valve's spring submerged in hydraulic fluid, preventing ice formation and maintaining the set point by using a low-pressure secondary valve to control fluid flow, eliminating the need for atmospheric exposure and debris filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional ball and spring pressure relief valve is used, then the valve is simple and light, but ice formation at cold temperatures alters the set point and causes unreliable operation
Solution Approach 1:
The patent submerges the spring and valve ball in hydraulic fluid to create an inert environment that prevents ice formation. The hydraulic fluid displaces atmospheric moisture and maintains a controlled environment around the critical components, eliminating the harmful effect of ice formation at cold temperatures while preserving the simple ball and spring valve design.
2Reliability
If the valve is exposed to atmosphere, then the structure is simple, but debris can interfere with the set point and adversely affect reliability
Solution Approach 1:
The hydraulic fluid creates an inert environment that excludes debris from contacting the spring and valve ball. This fluid barrier prevents contaminants from interfering with the valve's set point mechanism, improving reliability without requiring complex filtration systems or exposing the components to the atmospheric environment.
3Reliability
If heating devices are incorporated to prevent ice formation, then ice prevention is achieved, but the device size and weight increase making it infeasible for aircraft applications
Solution Approach 1:
The patent uses hydraulic fluid to create an inert environment that passively prevents ice formation without requiring active heating devices. This approach maintains the compact and lightweight design necessary for aircraft applications while effectively eliminating ice formation risks through environmental control rather than thermal management.
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
Ensures reliable operation of the pressure relief valve within the desired tolerance range, preventing damage to the cowl opening system by maintaining the set point and preventing ice formation, thus ensuring efficient and safe maintenance.
Implementation Method 1
hydraulic fluid contained within the pump is pumped into the actuator
Implementation Method 2
If the pressure from the pumped fluid acting on the ball against the spring force exceeds a set point
Implementation Method 3
the ball is seated, under the bias of the spring, in a valve seat
Implementation Method 4
under the bias of the spring
Implementation Method 5
the secondary valve also opens to allow passage of the fluid from the fluid line through the valve housing
Data Source
Figure 1~2
Figure 3A~3B
Figure 3C~3E
AI summary
A pressure relief valve assembly comprising a valve housing within which is provided a primary pressure relief valve having a valve ball and a valve spring, the valve spring biasing the valve ball in a first direction into a valve seat to prevent the passage of fluid from a fluid line through the valve, and wherein the spring force is selected such that a fluid force above a predetermined set point acting against the ball in a second direction opposite the first direction causes the ball to move out of the valve seat against the spring force to allow fluid to flow from the fluid line through the valve seat and through the valve, and wherein a secondary valve is positioned relative to the primary valve to retain fluid around the valve spring of the primary valve at a fluid force below the predetermined set point.