Impeller Projection Seal for Misalignment-Tolerant Backflow Control
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Solution Overview
Problem
Centrifugal pump designs with labyrinth-type seals are not tolerant to axial or angular misalignment, leading to reduced sealing efficiency and increased backflow of coolant, which affects the overall efficiency of the pump system.
Innovation Solution
The impeller features a plurality of projections that extend axially and circumferentially, which are received in corresponding recesses in the pump housing, creating a tortuous flow path that restricts backflow by providing a high-pressure drop route, thereby minimizing coolant flow from the outlet back to the inlet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a labyrinth-type seal is provided in the pump housing, then sealing between the impeller and housing is improved, but the system becomes sensitive to axial and angular misalignment, reducing sealing efficiency
Solution Approach 1:
The seal is divided into multiple discrete projections (at least three) distributed circumferentially around the impeller periphery. Each projection engages with corresponding recesses in the housing to create individual sealing zones, collectively forming a robust seal that tolerates misalignment better than a continuous labyrinth structure.
Solution Approach 2:
The sealing mechanism transitions from a traditional planar labyrinth seal to a three-dimensional protruding projection structure that extends axially from the impeller surface. This dimensional change allows the seal to maintain contact and sealing effectiveness despite axial and angular misalignment between the impeller and housing.
2Loss of energy
If a seal is provided between the impeller and pump housing, then backflow of fluid is reduced, but the flow path becomes more restricted, affecting fluid flow characteristics
Solution Approach 1:
The projections are strategically positioned at specific circumferential locations rather than providing continuous sealing. This localized sealing approach prevents backflow at critical zones while maintaining adequate flow paths through unobstructed regions, balancing sealing effectiveness with fluid flow requirements.
Solution Approach 2:
Multiple identical projections are distributed around the impeller periphery, creating redundant sealing zones. This multiplication of sealing elements provides comprehensive backflow prevention while the distributed arrangement ensures that not all flow paths are blocked simultaneously, maintaining system productivity.
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 design enhances the volumetric efficiency of the pump system by reducing unwanted coolant flow, is less sensitive to misalignment, and maintains efficiency across varying flow rates, including high cooling demands in vehicles.
Implementation Method 1
the flow path provides a tortuous flow route for fluid between an inlet and outlet of the pump assembly so as to restrict flow of fluid along said flow path and thereby minimise flow of fluid from the outlet back towards the inlet
Data Source
AI summary
An impeller for use in a pump assembly for a fluid circuit of an engine of a vehicle comprises a plurality of projections provided at radially spaced locations relative to a rotational axis of the impeller, the impeller being rotatable relative to a housing of the pump assembly. The projections extend axially from a surface of the impeller and circumferentially about the rotational axis of the impeller. At least one of the projections is configured to be at least partially received in a recess provided in the housing such that a flow path is provided by the projection and the respective recess, wherein the flow path provides a tortuous flow route for fluid between an inlet and outlet of the pump assembly so as to restrict flow of fluid along said flow path and thereby minimise flow of fluid from the outlet back towards the inlet in a direction opposite to the intended direction of flow.