Shaft Sealing Arrangement with Dynamic Pressure Control
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Solution Overview
Problem
Existing sealing arrangements for shafts face challenges in regulating contact pressure, leading to increased friction and wear at high speeds, and require external control for pressure changes, which is impractical in many systems.
Innovation Solution
A flexible system that adjusts contact pressure by generating a flow in the first medium, using a flow generator connected to the shaft, which reduces or increases contact pressure based on rotation speed, thereby mitigating friction and wear without external control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact force of the sealing element against the shaft is increased to counteract leakage caused by high-pressure medium, then the sealing performance is improved, but the friction of the sealing element increases leading to increased wear and temperature increase
Solution Approach 1:
The sealing element incorporates a resilient biasing mechanism that dynamically adjusts the contact force based on operating conditions. The resilient material allows the sealing element to deform and adapt its contact pressure automatically, providing high contact force when needed for sealing while reducing contact force under high-speed conditions to minimize friction and wear.
Solution Approach 2:
The invention changes the physical state and properties of the sealing element by using a resilient material whose mechanical properties (elasticity, damping) can be tailored. This allows the contact force parameter to vary dynamically in response to pressure differentials and rotational speed, optimizing the balance between sealing performance and friction reduction.
2Reliability
If the contact force of the sealing element is increased to maintain sealing at high pressure differentials, then the tightness between media is improved, but the temperature increase due to friction can cause thermal damage to the sealing element and media
Solution Approach 1:
The resilient biasing mechanism provides dynamic adaptation of contact force, automatically reducing the contact pressure when rotational speed increases and frictional heating becomes significant. This dynamic response prevents excessive temperature buildup while maintaining adequate sealing force when operational conditions require it.
Solution Approach 2:
The resilient material inherently provides cushioning and shock absorption capabilities, dampening the impact of pressure surges and reducing peak contact forces that would otherwise generate excessive heat. This prior cushioning effect protects both the sealing element and the media from thermal damage before it occurs.
3Force
If a sealing ring is pre-curved towards the high-pressure side to be pressed directly against the shaft by medium pressure, then the contact force increases with pressure differential, but external control mechanisms are required which are impractical in many systems
Solution Approach 1:
The sealing element is designed to be self-regulating through its resilient properties. The biasing force is generated internally by the resilient material itself, eliminating the need for external actuators, sensors, or control systems. The sealing element automatically adjusts its own contact force in response to the pressure differential and rotational speed conditions.
Solution Approach 2:
The invention extracts and eliminates the complex external control mechanisms from the sealing system. Instead of using external actuators or control systems to adjust contact force, the solution relies solely on the inherent resilient properties of the sealing element material to provide automatic force regulation.
4Object-generated harmful factors
If the counter surface area is reduced to decrease contact force at high shaft speeds, then friction is reduced, but the sealing effectiveness may be compromised
Solution Approach 1:
The resilient biasing mechanism enables dynamic adjustment of contact force, allowing the sealing element to maintain adequate sealing pressure on the reduced counter surface area. The contact force varies automatically with operating conditions, ensuring sufficient sealing effectiveness even when the counter surface area is minimized to reduce friction.
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 system effectively reduces frictional heat, extends seal life, and actively cools the sealing element, while also cleaning contaminants and preventing leakage, by adjusting contact pressure in response to shaft speed, enhancing operational reliability and efficiency.
Implementation Method 1
a flow generator (30) fixed to the shaft (12) and designed to generate a flow (32) in the first medium (26) that increases with the rotational speed of the shaft (12)
Implementation Method 2
This can be the case in particular when the sealing element also rotates and, at high speeds, the centrifugal force counteracts the contact force
Implementation Method 3
with increasing contact force under corresponding pressure conditions, the friction of the sealing element against the shaft or mating surface also increases
Implementation Method 4
the combination of high friction and high rotational speed leads to a significant temperature increase
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a sealing arrangement (10) for sealing between a first and a second medium (26, 28) in the region of a shaft (12), comprising a sealing element (16) made of a plastic material. One section (24) of the sealing element (16) bears against the shaft (12) or on a counter surface which is perpendicular to the shaft with a pressing force. Said sealing arrangement (10) comprises means (29) which reduce or increase the pressing force of the sealing element (16) by a targeted change in pressure in the first medium (26).