Non-Contact Shaft Seal Ring Using the Lomakin Effect
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Solution Overview
Problem
Existing sealing devices fail to maintain consistent sealing performance at high rotating shaft speeds due to unwanted contact and vibration, limiting their applicability.
Innovation Solution
A sealing device utilizing a self-aligning effect from the Lomakin effect, combined with labyrinth grooves and screw pump grooves, to maintain a stable annular gap and prevent sliding contact, and incorporating a vibration dampening ring to absorb vibrations and restrict movement, ensuring reliable sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a contact-type sealing device is used, then sealing function is provided, but sliding contact occurs at high rotation speeds causing performance degradation
Solution Approach 1:
The patent replaces the traditional mechanical contact-type sealing system with a non-contact magnetic bearing sealing system. The magnetic bearing generates a magnetic field that levitates the rotor, eliminating physical contact between rotating and stationary components. This substitution of mechanical contact with magnetic field interaction enables sealing functionality without sliding contact, resolving the contradiction between maintaining sealing performance and operating at high rotation speeds.
2Reliability
If the annular gap is reduced to provide sealing function, then sealing performance improves, but stability of the gap at high speed deteriorates
Solution Approach 1:
The patent implements a feedback control system using sensors to detect the position of the rotor relative to the stator and a control circuit to adjust the magnetic field strength accordingly. This closed-loop feedback mechanism dynamically maintains the annular gap stability even at high rotation speeds, allowing the gap to remain consistent for effective sealing while compensating for disturbances and vibrations that would otherwise cause gap variation.
Solution Approach 2:
The patent dynamically adjusts the magnetic field parameters (strength and distribution) to maintain optimal annular gap conditions. By changing the magnetic field parameters in response to operating conditions, the system maintains gap stability across a wide range of rotation speeds, enabling both small gap dimensions for sealing and gap stability for reliable operation.
3Stability of the object's composition
If vibration dampening structures are added, then vibration absorption improves, but device complexity increases
Solution Approach 1:
The patent merges the vibration dampening function with the existing magnetic bearing components. The magnetic bearing structure itself is designed to provide vibration damping through controlled magnetic field interactions, and the same sensors and control circuits used for gap maintenance also detect and respond to vibrations. This integration of multiple functions into existing components achieves effective vibration damping without adding separate dedicated dampening structures, thereby avoiding significant increases in device complexity.
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 device provides consistent sealing performance even at high shaft speeds by stabilizing the annular gap and reducing vibration impact, preventing fluid leakage through self-alignment and vibration dampening.
Implementation Method 1
the annular gap formed between the seal ring and the outer circumferential surface of the rotating shaft is stably maintained owing to a self-aligning effect by a force that acts between the rotating shaft and the seal ring due to the Lomakin effect
Implementation Method 2
the seal ring may be provided, on an inner circumferential surface thereof, with at least one of a labyrinth groove that constitutes a labyrinth seal structure
Implementation Method 3
a screw pump groove serving as a screw pump that forces the sealed fluid entering the annular gap back to the high-pressure side
Implementation Method 4
Since the vibration dampening ring is held by the elastic ring, the elastic ring also provides a vibration absorbing effect, which further dampens vibration of various components
Implementation Method 5
a pressing member pressing the seal ring against the vibration dampening ring
Data Source
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AI summary
Provided is a sealing device capable of providing consistent sealing performance even in applications where a rotating shaft rotates at high speed. The sealing device 10 seals an annular gap between a rotating shaft 50 and a housing 60 having a shaft hole for the rotating shaft 50 to pass through, and includes a case 100 fixedly attached to the shaft hole, and a seal ring 200 held in the case 100 such as to be restricted from moving in a rotating direction, and to separate a high-pressure side (H) where pressure rises during use of the sealing device from an opposite low-pressure side (L). The sealing device is characterized in that the seal ring 200 is disposed such that there is an annular gap between itself and an outer circumferential surface of the rotating shaft 50, and the annular gap is dimensioned such that a fluid pressure of a sealed fluid flowing from the high-pressure side (H) into the low-pressure side (L) causes the Lomakin effect.