Centrifugal Pump Impeller Laser Welding Symmetry Control
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Solution Overview
Problem
Centrifugal pump impellers made from fiber-reinforced plastic materials face asymmetry issues due to ultrasonic and mechanical welding methods, leading to increased leakage flow and reduced pump efficiency.
Innovation Solution
An impeller design with a first shroud and a second shroud welded together using a laser welding process, where at least one blade is connected via a welded joint in a specific apex area section and free of joints in other sections, allowing for precise adjustment and minimizing deformation, with one cover pane made of light-transmitting and the other of light-absorptive material to control the welding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ultrasonic welding is used to join impeller parts, then the parts can be connected, but asymmetries and impeller eccentricity occur due to local melting and deformation
Solution Approach 1:
The patent applies local quality by using laser welding only in specific regions (first section of apex area) rather than uniformly across the entire blade apex. This localized welding approach allows the blade to maintain symmetry in non-welded areas while achieving secure connection in critical regions, thereby resolving the contradiction between welding capability and impeller symmetry.
Solution Approach 2:
The apex area of the blade is segmented into multiple sections (first section with welded joints, second and third sections free of weld joints). This segmentation allows different portions of the blade to have different welding states, enabling the impeller to maintain overall symmetry while achieving necessary connections in specific regions.
2Ease of manufacture
If mechanical joining methods with groove-like structures are used, then parts can be connected, but inaccuracies in grooves cause impeller asymmetry
Solution Approach 1:
The patent replaces mechanical joining methods (groove-like structures) with laser welding technology. This substitution eliminates the need for precise groove fabrication and assembly alignment, thereby achieving more consistent impeller symmetry while maintaining effective joining capability.
3Strength
If welded joints are applied across the entire apex area, then strong connection is achieved, but deformation and eccentricity increase
Solution Approach 1:
The apex area is divided into multiple sections with different welding configurations. The first section receives welded joints for strong connection, while the second and third sections remain free of weld joints to prevent deformation. This segmentation allows the impeller to achieve necessary connection strength without the adverse effects of complete apex area welding.
Solution Approach 2:
Different regions of the apex area are assigned different welding qualities - the first section has welded joints for strength, while other sections remain unwelded to maintain symmetry. This local differentiation resolves the contradiction between connection strength and impeller symmetry.
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 prevents deformation and eccentricity, ensuring a tight seal between the impeller and pump housing, thereby enhancing pump efficiency by reducing leakage flow.
Implementation Method 1
at least one blade (8) from the number of blades is connected to the second cover disk (6) via a welded joint (40) in a first section (20) of the apex area (12)
Implementation Method 2
The ultrasound creates a bond when the contact points between the parts begin to melt. Ultrasonic welding causes local melting of the plastic due to the absorption of vibration energy
Implementation Method 3
one of the first and second cover panes is made of light-transmitting material and the other of the first and second cover panes is made at least partially of light-absorptive material
Data Source
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AI summary
Impeller for a centrifugal pump with a first cover plate (6) having a number of blades (8) and a second cover plate attached to the first cover plate (6) by welding, wherein each blade has a crown region (12) at which it contacts the second cover plate, wherein at least one blade (8) of the number of blades (8) has a welded connection with the second cover plate in a first section (20) of the crown region (12) and is free of a welded connection in at least a second section (14, 16) of the crown region (12).