Mechanical Seal Banded Ring Asymmetric Stress
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Solution Overview
Problem
Mechanical end face seals in industrial applications, particularly in dry running conditions, experience high-pitched squealing due to harmonic vibrations resulting from the rubbing characteristics of the seal face materials and structural influences, which existing solutions, such as material changes and vibration damping, have failed to effectively mitigate.
Innovation Solution
A metal ring with intermittent sections is pressed onto the carbon ring's outer diameter, creating asymmetric stress distribution and radial pressure, disrupting harmonic vibrations and self-polishing effects, thereby reducing noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dry running seal faces are used to maintain sealing function, then sealing performance is improved, but harmonic vibration and squealing noise occur
Solution Approach 1:
The patent applies controlled mechanical vibration by introducing a sinusoidal waviness pattern on the seal face surface. This deliberate vibration pattern disrupts the harmonic vibrations that cause squealing noise while maintaining the dry running sealing function. The waviness creates a controlled lubrication mechanism that prevents the high-frequency vibration harmonics responsible for the harmful squealing sound.
2Reliability
If seal face materials are changed to reduce wear and improve sealing, then sealing performance is improved, but squealing noise persists
Solution Approach 1:
The patent applies local quality by introducing a sinusoidal waviness pattern at a specific location on the seal face surface. This localized geometric modification creates areas of varying surface height that provide controlled lubrication pockets, reducing the harmful harmonic vibrations and squealing noise while maintaining the overall sealing performance of the seal face material.
3Object-generated harmful factors
If vibration damping methods are applied to reduce noise, then squealing is reduced, but sealing performance deteriorates
Solution Approach 1:
The patent applies curvature by introducing a sinusoidal waviness pattern on the seal face surface. This curved geometric pattern creates lubrication pockets and controlled clearance zones that reduce harmful vibrations and squealing noise without compromising the sealing function. The curved waveform maintains contact between seal faces while providing noise attenuation.
4Reliability
If self-polishing action occurs on seal faces, then initial sealing is improved, but harmonic vibration and squealing increase over time
Solution Approach 1:
The patent applies periodic action by introducing a sinusoidal waviness pattern that creates repeating lubrication pockets around the seal face circumference. This periodic geometric feature ensures continuous lubrication as the seal operates, preventing the development of harmful harmonic vibrations and squealing that occur with smooth self-polishing surfaces.
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 effectively interrupts harmonic vibrations and self-polishing, leading to quiet operation by maintaining the necessary stress and lubrication between the seal faces, applicable to both dry running and liquid seals.
Implementation Method 1
The stress band includes a plurality of radially inwardly directed pads disposed asymmetrically about the ring circumference. These pads are in interference fitting contact with the outer cylindrical surface of the seal ring. It imparts radially inward compressive forces to the annular seal ring.
Implementation Method 2
A metal ring with intermittent sections is pressed onto the carbon ring's outer diameter, creating asymmetric stress distribution and radial pressure
Implementation Method 3
maintaining the necessary stress and lubrication between the seal faces
Implementation Method 4
The changing state of stress on the primary ring serves to interrupt harmonic vibration at the seal faces
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
A mechanical end face seal with a pair of annular relatively rotating seal face (16,18) defining seal rings. An annular compression contact ring disposed in surrounding relation to one of the seal rings (70) includes a plurality of pads (80) at asymmetrical locations in interference contact with the outer cylindrical surface of the ring (32).