Rotary Machine Seal Flushing With Adjustable Axial Leakage Gap
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Solution Overview
Problem
Existing rotary machines face challenges in reliably and efficiently flushing the sealing element, leading to wear and potential damage due to improper dimensioning of leakage gaps, which can result in excessive wear or failure.
Innovation Solution
The rotary machine features an adjustable axial leakage gap within the flush casing, allowing for optimal fitting post-installation, ensuring high flushing fluid velocity and minimizing wear, with the flush casing being movable to adjust the gap width after mounting, enabling precise control of the flushing fluid velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the width of the leakage gaps is made small to increase flushing fluid velocity, then the sealing effectiveness is improved, but the risk of excessive wear and physical contact increases
Solution Approach 1:
The invention makes the axial leakage gap adjustable rather than fixed. The flush casing can be positioned at different axial locations to change the gap width between the bushing and impeller. This dynamic adjustment capability allows the system to optimize the balance between sealing effectiveness and wear prevention by selecting appropriate gap widths for different operating conditions.
Solution Approach 2:
The invention changes the parameter of axial leakage gap width from a fixed value to an adjustable parameter. By modifying the axial position of the flush casing, the gap width can be varied to achieve optimal flushing fluid velocity that prevents both inadequate sealing and excessive wear.
2Speed
If the width of the axial leakage gap is too small, then the flushing fluid velocity increases, but the fluid film may tear off causing physical contact between bushing and impeller
Solution Approach 1:
The adjustable axial position of the flush casing enables dynamic control of the leakage gap width. This allows operators to find and maintain the optimal gap width that sustains a stable fluid film while achieving sufficient flushing velocity, preventing fluid film tear-off and physical contact between components.
3Ease of manufacture
If the leakage gap width is fixed during manufacturing, then the manufacturing process is simplified, but the flushing performance cannot be optimized after installation
Solution Approach 1:
The invention introduces adjustability to the otherwise fixed manufacturing structure. The flush casing can be positioned and fixed at different axial locations after installation, allowing optimization of flushing performance in the field without complicating the manufacturing process. The basic structure remains simple, but gains post-installation adaptability.
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 solution enhances the reliability and reduces wear on the sealing unit, minimizes flushing fluid consumption, and simplifies manufacturing and maintenance by allowing for adjustable gap settings, ensuring efficient operation and reduced maintenance efforts.
Implementation Method 1
a flushing fluid, for example water, is introduced into the flush chamber, passes through the radial leakage gap, then through the axial leakage gap and is discharged
Implementation Method 2
Another important function of flushing the sealing unit, in particular when the process fluid is hot, is the cooling of the sealing unit by the flushing fluid
Data Source
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AI summary
A rotary machine for acting on a process fluid is proposed, comprising an impeller (2) for acting on the process fluid, a shaft (3), on which the impeller (2) is mounted, a drive unit (4) operatively connected to the shaft (3) for rotating the shaft (3) and the impeller (2) about an axial direction (A), a sealing unit (6) having a sealing element (61) for sealing the shaft (3) during rotation of the shaft (3), and a flush casing (7) configured to receive a flushing fluid for flushing the sealing element (6), wherein the flush casing (7) is configured to delimit an annular flush chamber (71) extending about the seal element (61), wherein the flush casing (7) comprises a bushing (72) surrounding the sealing element (61) and delimiting a radial leakage gap (8) arranged between the sealing element (61) and the bushing (72), and wherein the bushing (72) is arranged and configured to delimit an axial leakage gap (9) between the impeller (2) and the bushing (72), wherein the width (L9) of the axial leakage gap (9) in the axial direction (A) is adjustable.