Bi-Directional Shear Seal Relief Valve for Vent Overpressure
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Solution Overview
Problem
Relief valves experience sealing integrity loss due to undesirable lifting of the shear seal element from the seal plate, caused by overpressure conditions in the vent line, leading to potential failure, and there is a challenge in monitoring the valve's opening pressure in situ after installation.
Innovation Solution
A relief valve design featuring a bi-directional seal between the shear seal element and its bore, with a user-settable bias spring and an annular pressure-leveraging face, along with a check valve and pumping port mechanism for in-situ pressure checking and calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uni-directional seal is used between the shear seal element and the seal plate, then the valve can maintain sealing integrity under normal pressure conditions, but the seal lifting off occurs when vent line overpressure conditions exist, causing sealing integrity loss and potential valve failure
Solution Approach 1:
The patent applies the inversion principle by designing a bi-directional seal arrangement where the shear seal element can seal against both the seal plate and the bore wall. Instead of relying solely on the seal plate for sealing (uni-directional), the seal element is configured to seal in reverse against the bore wall when vent pressure exceeds inlet pressure, thereby preventing seal lifting off and maintaining sealing integrity under overpressure conditions
Solution Approach 2:
The patent applies the counterweight principle by providing a biasing spring that exerts a force on the shear seal element to counteract the lifting force generated by vent line overpressure. The biasing spring maintains the shear seal element in contact with the seal plate even when vent pressure attempts to lift the seal, thereby preventing sealing integrity loss and valve failure
2Adaptability or versatility
If the valve is installed in a fluid circuit, then the valve can operate in its intended application, but it becomes difficult or impossible to monitor the opening pressure in situ
Solution Approach 1:
The patent applies the intermediary principle by introducing a transducer that converts the mechanical opening pressure of the valve into an electrical signal. The transducer acts as an intermediary device that enables remote monitoring and measurement of the valve's opening pressure without requiring direct access to the valve itself, thereby solving the difficulty of in-situ pressure monitoring while the valve remains installed in the fluid circuit
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 bi-directional seal ensures the valve's performance is not impacted by overpressure conditions, and the in-situ pressure checking mechanism allows for proper calibration of the valve's opening pressure, enhancing sealing integrity and operational reliability.
Implementation Method 1
A bias spring is present in the piston, the force of which biases the shear seal element toward the seal plate
Implementation Method 2
A bi-directional seal between the shear seal element and its bore, with a user-settable bias spring and an annular pressure-leveraging face
Implementation Method 3
a check valve and pumping port mechanism for in-situ pressure checking and calibration
Data Source
AI summary
A pressure relief valve includes a valve body including a monitored pressure inlet leading to a monitored pressure region, a piston having a shear seal bore and a surface facing the monitored pressure region, a vent passage and a the shear seal assembly comprising a seal plate having a sealing surface thereon, and the shear seal assembly includes a sealing surface facing the seal plate and having a first annular area, and a first surface having an annular surface area at least twice as large as the first area of the sealing surface, the first surface facing away from the first area, and a biasing seal in contact with the first surface.