Mechanical Seal Sliding Surfaces for Faster Startup Liquid Discharge
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Solution Overview
Problem
In mechanical seals with sliding components, the sealed liquid takes a long time to discharge when the rotary machine is started, leading to potential performance issues due to high load during startup, as it enters the gas side due to capillary phenomenon when the machine is stopped.
Innovation Solution
The sliding components are designed with a dynamic pressure generation groove on one surface and an annular groove on the other, increasing the gas-liquid interface area, suppressing liquid entry into the gas side, allowing quick transition to a non-contact state at high-speed rotation by leveraging surface tension and maintaining surface strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealed liquid is present between sliding surfaces when the rotary machine is stopped, then the sliding surfaces can be protected from direct contact, but the sealed liquid takes a long time to discharge when starting the machine
Solution Approach 1:
The sliding surface is segmented into multiple regions by grooves (radial groove and circumferential groove), creating separate chambers that control the discharge path of the sealed liquid. This segmentation allows the liquid to be discharged systematically through designated paths rather than remaining trapped, reducing discharge time while maintaining surface protection.
Solution Approach 2:
The invention introduces grooves that extend in the radial direction and circumferential direction, adding dimensional pathways for liquid discharge. The radial groove provides a radial discharge path, while the circumferential groove provides a tangential discharge path, creating multi-dimensional discharge channels that accelerate liquid removal without compromising sliding surface protection.
2Reliability
If the sliding surfaces are kept in contact to maintain sealing, then sealing performance is improved, but friction and energy loss increase
Solution Approach 1:
The invention creates a dynamic sealing mechanism where the sealed liquid forms a lubricating film between sliding surfaces during operation. The grooves facilitate the formation and maintenance of this liquid film, allowing the system to transition from static contact to dynamic fluid-film lubrication, reducing friction and energy loss while maintaining sealing effectiveness.
Solution Approach 2:
The invention utilizes hydraulic principles by employing the sealed liquid itself as a lubricating medium. The grooves are designed to maintain an appropriate thickness of the liquid film between sliding surfaces, creating a hydrodynamic lubrication effect that reduces direct contact friction while preserving sealing performance through the liquid barrier.
3Productivity
If grooves are added to the sliding surface to facilitate liquid discharge, then discharge speed is improved, but the strength of the sliding surface may be reduced
Solution Approach 1:
The grooves are designed with specific local characteristics: they are positioned at predetermined locations rather than uniformly distributed, and have controlled depths and widths. The radial groove and circumferential groove are strategically placed to provide discharge pathways while minimizing material removal from critical load-bearing areas, thus maintaining overall sliding surface strength while enabling effective liquid discharge.
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 enables rapid shifting to a non-contact state, reducing rotation resistance and improving machine performance by minimizing the amount of liquid to be discharged at startup, while maintaining surface strength and preventing dynamic pressure deterioration.
Implementation Method 1
a dynamic pressure generation groove which communicates with a gas side in a radial direction and which is configured to generate a dynamic pressure between the sliding surfaces of the first and second sliding components by the gas during a running of the rotary machine
Implementation Method 2
since the sealed liquid enters the groove formed on at least one of the sliding surfaces of the first and the second sliding components when the rotary machine is stopped, the surface area of the gas-liquid interface increases and the sealed liquid can be further suppressed from entering the gas side by the surface tension of the wide gas-liquid interface
Implementation Method 3
the sealed liquid can be further suppressed from entering the gas side by the surface tension of the wide gas-liquid interface
Data Source
AI summary
A pair of sliding components are disposed at a relatively rotating position at the time of running a rotary machine and formed in an annular shape in which a sealed liquid is present on one side of an inner radial side and an outer radial side and a gas is present on the remaining side thereof. A sliding surface of a sliding component is provided with a dynamic pressure generation groove which communicates with the side of a gas in a radial direction and which is configured to generate a dynamic pressure between the sliding surfaces by the gas at the time of running the rotary machine. A sliding surface of a sliding component is provided with a groove which extends in a circumferential direction.