Pump Stator Bore Sealing With Abradable Circumferential Protrusion
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Solution Overview
Problem
Existing multi-stage pump assemblies face challenges in sealing between the rotor and stator, leading to leakage issues due to unsuitable seal arrangements that often expand the radial separation, creating a circumferential leakage path.
Innovation Solution
A pump assembly with a circumferential protrusion extending radially into the bore between the rotor shaft and stator, where the protrusion and contacting surfaces are configured to abrade each other, providing a unique, bespoke seal by filling the gap and maintaining tight tolerances through material wear, potentially using different hardness materials for enhanced sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing seal arrangements are used between rotor and stator, then sealing is provided, but the radial separation is expanded creating a circumferential leakage path
Solution Approach 1:
A circumferential protrusion is introduced as an intermediary element between the rotor shaft and stator bore. This protrusion extends radially into the bore and works with a corresponding recess to create a sealing interface that prevents both axial and circumferential leakage without expanding the overall radial separation between rotor and stator.
Solution Approach 2:
The invention accepts that contact and wear between the protrusion and rotor shaft will occur, but converts this potentially harmful wear mechanism into a beneficial self-sealing process. The softer protrusion material is designed to abrade against the harder rotor shaft, creating a custom-fit sealing interface that improves sealing effectiveness over time.
2Reliability
If a circumferential protrusion is added to seal between rotor and stator, then leakage is prevented, but device complexity increases
Solution Approach 1:
The sealing function is merged with the existing rotor-stator interface structure. The circumferential protrusion is integrated into either the rotor shaft or stator bore design, combining the sealing element with the rotational assembly rather than adding a separate, independent sealing mechanism.
Solution Approach 2:
The protrusion and recess are designed with specific local geometric features at the sealing interface, including controlled hardness differences and precise dimensional relationships. These localized quality variations create an effective seal without requiring changes to the overall structural design of the pump assembly.
3Reliability
If different hardness materials are used for protrusion and rotor shaft, then abrasion seal is enhanced, but manufacturing precision requirements increase
Solution Approach 1:
The invention changes the material parameter (hardness) of the protrusion relative to the rotor shaft, making the protrusion softer to enable controlled abrasion. This parameter change creates a self-adjusting sealing mechanism where the softer material conforms to the harder surface through wear, compensating for manufacturing tolerances rather than requiring extremely tight initial precision.
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 abrading mechanism creates a close, rotatable seal that minimizes both axial and circumferential leakage, effectively preventing fluid leakage and maintaining tight tolerances between the rotor and stator, even under conditions of temperature changes and vibration.
Implementation Method 1
one of the protrusion and a corresponding surface of the rotor shaft portion or the bore portion being configured to be abraded by the other upon experiencing contact therewith
Implementation Method 2
one of the protrusion and a corresponding surface of the rotor shaft portion or the bore portion being configured to be abraded by the other upon experiencing contact therewith
Implementation Method 3
the protrusion and the bore portion or the protrusion and the rotor shaft portion may be so configured that when contact is experienced therebetween, one or more of the contacting surfaces is abraded
Data Source
AI summary
A pump assembly may include a rotor having a rotor shaft portion; a stator having a bore portion defining a bore for receiving the rotor shaft portion; and a circumferential protrusion extending radially into the bore between the bore portion and the rotor shaft portion, wherein at least one of the protrusion and a corresponding surface of the rotor shaft portion or the bore portion is configured to be abraded by the other upon experiencing contact therewith. In this way, the gap between the bore portion and the rotor shaft portion may be at least partially filled by the circumferential protrusion in order to provide a seal. The protrusion and one of the bore portion and the rotor shaft portion may be formed from different hardness materials.