Shaft Seal Rotor Ring Centrifugal Lubricant Drain
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Solution Overview
Problem
Existing rotary machines face challenges in preventing lubricant leakage through sealing arrangements, which can lead to contamination and damage, especially due to pressure differentials and the limitations of both contact and contactless sealing methods.
Innovation Solution
A sealing arrangement featuring a rotor ring co-rotating with the rotor to prevent axial flow and utilizing centrifugal forces to direct lubricant away from the rotor, combined with a drain chamber and discharge passage to collect and control lubricant, ensuring it does not escape to the environment or reach the rotor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a contactless sealing element (labyrinth seal) is used, then friction losses and wear are reduced, but leakage flow along the shaft increases
Solution Approach 1:
The sealing arrangement is divided into multiple functional segments: an upstream contactless sealing element (labyrinth seal) for reducing friction, a downstream contact sealing element (slinger) for blocking leakage, and a rotor ring with centrifugal force generation. This segmentation allows each component to specialize in one function, resolving the contradiction between low friction and low leakage.
Solution Approach 2:
The rotor ring acts as an intermediary element between the upstream and downstream sealing elements. It receives lubricant that leaks through the labyrinth seal, uses centrifugal force to redirect it radially outward, and prevents it from reaching the rotor. This intermediary mechanism bridges the gap between the two sealing approaches.
2Loss of substance
If a contact seal (gland, stuffing box, or lip-seal) is used, then leakage flow is reduced, but energy consumption increases and wear occurs
Solution Approach 1:
The sealing arrangement is divided into multiple functional segments: an upstream contactless sealing element (labyrinth seal) for reducing friction, a downstream contact sealing element (slinger) for blocking leakage, and a rotor ring with centrifugal force generation. This segmentation allows each component to specialize in one function, resolving the contradiction between low friction and low leakage.
3Productivity
If pressure differentials are present in the rotor, then pumping action is enhanced, but lubricant suction from the bearing unit to the rotor increases
Solution Approach 1:
The rotor ring utilizes centrifugal force generated by rotor rotation to convert the rotational motion into a beneficial effect. This centrifugal force creates an outward radial flow that counteracts the inward axial suction caused by pressure differentials, transforming the rotational energy into a protective mechanism against lubricant leakage.
4Loss of substance
If the inner diameter of the rotor ring is made smaller to improve sealing, then contactless rotation is compromised
Solution Approach 1:
Different regions of the rotor ring have different functional qualities: the inner diameter is optimized for maintaining contactless rotation with the shaft, while the outer diameter and centrifugal force generation region are optimized for redirecting lubricant radially outward. This local differentiation of functional qualities resolves the contradiction between sealing performance and contactless operation.
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 effectively reduces lubricant leakage to both the rotor and the environment, maintaining the efficiency benefits of contactless sealing while enhancing sealing performance, even under pressure differentials.
Implementation Method 1
Due to the rotation of the rotor ring during operation the lubricant reaching the rotor ring is transferred by centrifugal forces away from the shaft area in a radially outward direction
Data Source
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AI summary
A rotary machine for acting on a fluid is proposed comprising a stationary housing (2), a rotor (3) for interacting with the fluid, a shaft (4) for rotating the rotor (3) about an axial direction (A), a bearing unit (5) for supporting the rotor (3), and a sealing arrangement (6) for sealing the bearing unit (5) with respect to the rotor (3), wherein the rotor (3) is arranged in the housing (2), and wherein the sealing arrangement (6) comprises a stationary sealing element (61) surrounding the shaft (4) and designed for a contactless sealing of the shaft (4), and wherein the sealing arrangement (6) further comprises a rotor ring (62) for preventing an axial flow along the shaft (4) to the rotor (3), and a cover plate (63), wherein the rotor ring (62) is rotationally fixedly connected to the rotor (3) and arranged axially adjacent to the sealing element (61), wherein the rotor ring (62) comprises a radially outer edge (622) extending in the axial direction (A) and surrounding the sealing element (61), wherein the cover plate (63) is fixed with respect to the housing (2) and surrounds the rotor ring (2), wherein the cover plate (63) has an outer rim (631) extending in the axial direction (A), wherein a drain chamber (64) is formed between the outer edge (622) of the rotor ring (62) and the outer rim (631) of the cover plate (63), and wherein a discharge passage (65) is provided for discharging the drain chamber (64).