Rippled Stopper Rod Nozzle for Metallurgical Flow Control
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Solution Overview
Problem
Traditional stopper rod systems for regulating liquid metal flow in metallurgical processes face issues with clogging due to non-metallic material deposition, leading to poor flow control and quality defects, as existing solutions like rugged geometries and gas introduction fail to provide uniform bubble distribution and effective turbulence control.
Innovation Solution
A stopper rod system with a uniquely designed stopper nose and nozzle bore featuring ripples that create a discontinuously increasing flow channel size downstream from the contact point, controlling turbulence and ensuring uniform gas bubble distribution to prevent clogging and improve flow regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rugged dimpled geometry is used on the stopper nose or nozzle bore surface, then clogging is reduced, but flow regulation precision deteriorates because aperture size is not a smooth function of separation distance
Solution Approach 1:
The patent applies a rippled surface geometry specifically at the critical interface region where the stopper nose contacts the nozzle bore, while maintaining smooth surfaces in other regions. This localized application of surface complexity provides clogging resistance precisely where particles are most likely to deposit, without disrupting the overall smooth aperture geometry needed for precise flow control.
Solution Approach 2:
The rippled surface consists of periodic undulations with specific curvature characteristics that create turbulence in the boundary layer without creating dead zones. The curved ripple structures differ from rugged dimples by providing continuous surface variation that promotes particle detachment while maintaining a predictable aperture size-separation relationship.
2Reliability
If gas is introduced through a porous element in the stopper nose, then clogging is reduced by bubble formation, but flow uniformity deteriorates due to asymmetric bubble distribution
Solution Approach 1:
The patent removes the porous gas injection element from the stopper nose entirely, eliminating the source of asymmetric bubble distribution. Instead, gas injection is implemented through a separate circumferential array of ports in the nozzle body, which distributes gas uniformly around the entire aperture perimeter, ensuring symmetric bubble formation and maintained flow uniformity.
Solution Approach 2:
The patent introduces a circumferential gas distribution system that acts as an intermediary between the gas source and the metal flow. This intermediate gas distribution structure ensures uniform gas delivery around the entire aperture, creating symmetric turbulence and bubble distribution that maintains flow uniformity while still preventing clogging.
3Manufacturing precision
If the stopper rod nose is moved close to the nozzle bore for precise flow control, then flow regulation is improved, but clogging risk increases due to particle deposition in the narrow gap
Solution Approach 1:
The rippled surface geometry is pre-configured on the stopper nose or nozzle bore to create controlled turbulence in the metal flow before it reaches the aperture. This preliminary turbulence action prevents particle settling and deposition in the narrow gap region, reducing clogging risk before particles can accumulate and interfere with precise flow control.
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 rippled design effectively reduces clogging deposition by controlling turbulence and ensures uniform gas bubble distribution, maintaining consistent metal flow and preventing quality defects in metal products.
Implementation Method 1
The stopper rod nose and the internal surface of the nozzle bore have a point of contact when the stopper rod system is in a closed position. At least one of the stopper rod nose and the internal surface of the nozzle bore comprises a plurality of ripples that are arranged such that the size of a flow channel between the stopper rod nose and the internal stopper rod when the stopper rod system is in an open position discontinuously increases in size as a function of the distance downstream from the point of contact.
Implementation Method 2
U.S. Pat. No. 5,071,043 discloses the use of a porous stopper nose to allow the introduction of bubbles of an inert gas such as argon into the metal flow. The introduction of gas helps to reduce clogging by providing bubbles to which the non-metallic particles in the liquid metal may preferentially attach, thereby reducing build-up on the stopper nose or nozzle bore.
Data Source
AI summary
The present invention concerns stopper rod system for use in a metallurgical vessel, comprising a stopper rod and a nozzle. At least one of the stopper rod nose and the internal surface of the nozzle bore comprise a plurality of ripples that are arranged such that the size of a flow channel between the stopper rod nose and the internal stopper rod when the stopper rod system is in an open position discontinuously increases in size as a function of the distance downstream from the point of contact between the stopper rod and the nozzle.