Molten Metal Pump Divergent Outlet and Coupling Unit
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Solution Overview
Problem
Molten metal pumps face challenges in efficiently removing magnesium from aluminum alloys due to poor reaction conditions, leading to undesirable chlorine and hydrogen chloride emissions, and existing designs suffer from mechanical stress and connection issues between graphite and metallic components.
Innovation Solution
The design incorporates a molten metal pump with a fan diffusing outlet passage that increases the cross-sectional area, a ceramic tip member for gas injection, and a coupling unit for adjustable connections between metallic and graphite components, reducing stress and emissions by optimizing gas dispersion and metal flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pump operates at higher speeds to increase chlorine reaction rate and magnesium removal efficiency, then productivity improves, but mechanical stress on pump components worsens
Solution Approach 1:
The patent applies dynamics by making the impeller speed adjustable and variable, allowing the system to operate at optimal speeds for magnesium removal while avoiding excessive mechanical stress. The pump can dynamically adapt its operating speed based on process requirements, combining high productivity during magnesium removal with lower speeds during normal operation to preserve component strength.
2Productivity
If a convergent nozzle is used in the outlet passage to increase metal flow velocity, then productivity improves, but mechanical stress and vibration worsen
Solution Approach 1:
The patent inverts the conventional convergent nozzle design by using a divergent outlet passage instead. The outlet passage increases in cross-sectional area from inlet to outlet, which reduces metal flow velocity and minimizes impact stress on the pump base and surrounding structures, while still maintaining adequate productivity through other means.
3Ease of manufacture
If graphite and metallic components are directly connected in the pump structure, then ease of manufacture improves, but reliability worsens due to differential thermal expansion
Solution Approach 1:
The patent introduces an intermediary coupling unit that connects graphite components (such as the impeller) to metallic components (such as the shaft). This coupling unit acts as a mediator that accommodates differential thermal expansion between the two materials, preventing stress concentration and connection failure while maintaining structural integrity. The coupling unit may include features such as clearance fits, flexible connections, or thermal expansion compensation mechanisms.
4Device complexity
If the outlet passage has constant cross-sectional area, then device complexity reduces, but harmful emissions worsen due to poor gas dispersion
Solution Approach 1:
The patent changes the geometric parameter of the outlet passage by making the cross-sectional area increase from inlet to outlet. This parameter change improves gas dispersion and reaction efficiency, reducing harmful emissions. The gradual expansion allows better mixing of molten metal and gas, enhancing magnesium removal while minimizing chlorine and hydrogen chloride emissions, all while maintaining a relatively simple overall design.
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 magnesium removal efficiency, reduces emissions, and improves mechanical stability by minimizing stress on pump components, allowing for higher operational speeds and deeper penetration of molten metal into the charge well.
Implementation Method 1
a fan diffusing outlet passage (574) increasing the cross-sectional area of the outlet passage (570)
Implementation Method 2
a ceramic tip member for gas injection
Implementation Method 3
The reaction of the molten aluminum with chlorine ultimately results in the formation of magnesium chloride
Implementation Method 4
The connection between the graphite post and the motor mount plate is subject to cyclic stresses resulting from differential thermal expansion of the graphite and the metal components
Data Source
AI summary
A molten metal pump includes an impeller, a pump base housing at least partially enclosing the impeller, a shaft connected to the impeller, a motor connected to the shaft, a motor mount plate for supporting the motor; and a post for connecting the motor mount plate to the pump base housing. The molten metal pump can include a connector that connects the post to the motor mount plate. The molten metal pump can include a socket for connecting the shaft to the motor. The shaft can comprise an assembly including an elongated metal rod having a first end and a second end and a metal non-circular drive member attached at the second end of the elongated metal rod. The impeller can include a cap member having a plurality of generally polygonally shaped inlet openings communicating with internal passages of the impeller, each inlet opening having an inner wall and an outer wall, the outer wall being longer than the inner wall, each inlet opening also including a leading wall and a trailing wall, the leading wall and the trailing wall each interconnecting the inner wall and the outer wall and each being inclined such that an uppermost edge of each wall precedes a lowermost edge of each wall in a first rotational direction.