Stepped Piston Pressure Relief Valve for Stable Pressure Release
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Solution Overview
Problem
Existing pressure relief valve designs are unstable at pressures close to the relief pressure, leading to excessive noise and vibration due to high-frequency operation and potential jamming or misalignment of valve components, causing wear and leakage.
Innovation Solution
A pressure relief valve assembly featuring a valve seat member with axial cavities and a piston with stepped cylindrical portions, where the piston is retained and aligned by these cavities to prevent tilting, combined with a damping cavity to stabilize movement and reduce oscillations, and optionally formed from low-friction materials like stainless steel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring-loaded ball or piston design is used for pressure relief valves, then the valve can maintain system pressure within specified limits, but the valve becomes unstable at pressures close to the relief pressure, causing high-frequency operation, noise and vibration
Solution Approach 1:
The valve seat member is divided into two separate cavities (first cavity and second cavity) that are axially spaced apart. The piston is segmented with two cylindrical portions (first cylindrical portion and second cylindrical portion) of different radii, each retained by a respective cavity. This segmentation provides separate retention zones that stabilize the piston axially, preventing high-frequency oscillations and improving operational stability near the relief pressure threshold.
2Device complexity
If a single cavity design is used for the piston, then the structure is simpler, but the piston may tilt instead of translating axially, causing wear, excess noise and vibration
Solution Approach 1:
The single cavity is segmented into two distinct cavities positioned at different axial locations. The first cavity retains the first cylindrical portion of the piston, while the second cavity retains the second cylindrical portion. This segmentation provides dual retention points that constrain the piston to pure axial translation, preventing tilting and misalignment, thereby improving reliability without excessive complexity.
3Ease of operation
If the piston is not properly aligned, then the valve structure allows more freedom of movement, but the piston tilts causing wear and leakage
Solution Approach 1:
The valve seat member is segmented into two cavities that axially space the retention zones. The piston is segmented with two cylindrical portions of different radii, each fitting into a respective cavity. This segmented configuration provides distributed constraint forces that maintain proper alignment during movement, preventing tilting that would cause the sealing surface to separate and leak, thus maintaining both movement freedom and sealing integrity.
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 stabilizes the valve operation, reduces noise and wear, and enhances longevity by maintaining axial alignment and damping oscillations, thereby ensuring reliable pressure regulation within hydraulic systems.
Implementation Method 1
The first cylindrical portion configured to be retained by and slidably engage with the first cavity and the second cylindrical portion configured to be retained by and slidably engage with the second cavity
Implementation Method 2
The arrangement of first and second cylindrical portions retained in first and second cavities on either axial side of piston sealing surface ensures that the piston is held in alignment on both axial sides of the piston sealing surface
Data Source
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AI summary
An assembly for a pressure relief valve includes a valve seat member (42), a piston (44) and a fluid outlet (62). The valve seat member includes a fluid inlet (46), a seat sealing surface (48) and an axial bore (50). The axial bore includes a first cavity (52) and a second cavity (56). The seat sealing surface is disposed axially between the first cavity and the second cavity and the fluid inlet is disposed axially between the seat sealing surface and the second cavity. The piston is movable within the axial bore. The piston includes a piston sealing surface (70), a first cylindrical portion (64) and a second cylindrical portion (68). The first cylindrical portion configured to be retained by and slidably engage with the first cavity and the second cylindrical portion configured to be retained by and slidably engage with the second cavity. The piston sealing surface is disposed axially between the first cylindrical portion and the second cylindrical portion. The piston has a first position in which the piston sealing surface is engaged with the seat sealing surface such that a fluid path between the fluid inlet and the fluid outlet is closed, and a second position in which the fluid path between the fluid inlet and the fluid outlet is open. The first cylindrical portion has a first radius, the second cylindrical portion has a second radius and the second radius is less than the first radius.