Shaft Sealing Device Micro Gap Uniformization
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Solution Overview
Problem
The existing shaft sealing mechanisms in rotary machines suffer from local variations in gas pressure distribution due to stack distortion and manufacturing errors, leading to uneven lifting characteristics and decreased seal performance, resulting in contact wearing between thin plate pieces and the rotation shaft.
Innovation Solution
A method of fabricating a shaft sealing device involves stacking and connecting thin plate pieces, followed by smoothing one lateral end surface to uniformize the micro gap spaces, ensuring consistent gas pressure distribution and preventing local variations in lifting characteristics, which includes using a jig with specific fitting portions to precisely position and smooth the end surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thin plate pieces are stacked and connected by welding to form a stacked body, then the shaft sealing device can be assembled, but stack distortion and manufacturing errors cause local variation in micro gap dimensions leading to non-uniform gas pressure distribution
Solution Approach 1:
The patent applies parameter changes by modifying the dimensional parameters of the side sealing plates. Specifically, the inner diameter dimensions of the high pressure side side sealing plate and low pressure side side sealing plate are adjusted to compensate for stack distortion. By changing these parameters, the gas pressure distribution in the micro gap is optimized to be uniform despite manufacturing variations in the stacked body.
2Reliability
If the inner diameter dimensions of side sealing plates are adjusted to set gas pressure distribution, then sealing performance is improved, but local variation in micro gap dimensions causes non-uniform lifting characteristics of thin plate pieces
Solution Approach 1:
The patent applies local quality by making the side sealing plates with different inner diameter dimensions. The high pressure side side sealing plate and low pressure side side sealing plate have specifically designed dimensional parameters that create a uniform gas pressure distribution pattern. This local dimensional variation in the sealing plates compensates for stack distortion and ensures uniform lifting characteristics across all thin plate pieces.
3Force
If non-uniform gas pressure distribution occurs in micro gap, then local variation in lifting characteristics occurs, but this leads to contact wearing between thin plate pieces and rotation shaft
Solution Approach 1:
The patent uses parameter changes to optimize the gas pressure distribution by adjusting the inner diameter dimensions of the side sealing plates. This creates a uniform gas pressure pattern in the micro gap, which in turn produces uniform lifting force on all thin plate pieces. The uniform lifting force prevents contact between the thin plate pieces and the rotation shaft, eliminating wear.
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 approach enhances seal performance by maintaining uniform gas pressure distribution across the micro gaps, reducing contact wearing and ensuring consistent sealing performance, thereby improving maintenance characteristics of rotary machines.
Implementation Method 1
a lifting force is applied to the thin plate pieces 103a by a dynamic pressure effect when the rotation shaft R is rotated
Data Source
AI summary
Provided is a method of fabricating a shaft sealing device, in which a plurality of thin plate pieces arranged in a circumferential direction of a rotation shaft are provided and base ends of the thin plate pieces are mutually connected, the method including a stacking step of stacking the plurality of thin plate pieces in one direction, a connecting step of mutually connecting the base ends of the plurality of stacked thin plate pieces to form a stacked body, and a first smoothing step of bringing one lateral end surface of two lateral end surfaces of the stacked body formed by each end portion in a width direction of the plurality of thin plate pieces in contact with a flat surface to smooth the other lateral end surface.