Gas Wiping Nozzle with Rectification Pieces for Steel Strip Plating
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Solution Overview
Problem
Existing gas wiping devices for steel strips in molten metal plating suffer from overcoating and splashing issues at the edges due to turbulence caused by gas nozzle collisions, which conventional solutions like slit blocking mechanisms and gas flow adjustments cannot completely eliminate.
Innovation Solution
A gas wiping device with a hollow nozzle featuring slidable blocking members and rectification pieces that maintain a consistent gas flow passageway and outlet width, preventing vortex formation and ensuring uniform gas distribution, thereby eliminating overcoating and splashing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the gas outlet width is reduced to decrease overcoating and splashing, then the gas flow is contracted and vortexes are produced, but this causes intermittent overcoating or splashing at the edges
Solution Approach 1:
The gas outlet is segmented into multiple smaller outlets arranged in an array along the width direction of the steel strip. Each small outlet has a width of 5-20mm, and there are 10-50 outlets in total. This segmentation prevents the formation of large vortexes while maintaining uniform gas distribution across the steel strip width, thereby eliminating both edge splashing and intermittent overcoating.
Solution Approach 2:
The gas outlet structure transitions from a single large outlet to multiple small outlets with specific width dimensions (5-20mm). This local quality change in the outlet configuration ensures that gas flow is distributed uniformly across different locations (local areas) of the steel strip width, preventing vortex formation at edge regions while maintaining overall coating uniformity.
2Area of stationary object
If opposing gas wiping nozzles are used to cover the entire steel strip width, then gas coverage is improved, but turbulence is produced by collision of gas streams near the edges
Solution Approach 1:
The gas wiping system uses multiple small gas outlets (10-50 outlets) arranged in an array across the width direction instead of a single large outlet or opposing nozzles. Each outlet has a width of 5-20mm. This segmentation allows gas to be distributed across the entire steel strip width while preventing stream collision turbulence, as the multiple small streams do not collide as intensely as opposing large streams would.
3Manufacturing precision
If the gas flow rate is increased to improve coating uniformity, then overcoating is reduced, but splashing increases at the edges
Solution Approach 1:
The gas flow is segmented into multiple small streams through 10-50 outlets of 5-20mm width each. This segmentation allows the total gas flow rate to be maintained or increased for uniform coating, while each individual small stream has sufficient control to prevent edge splashing. The distributed outlet configuration ensures that high flow rates do not concentrate at edges, thereby achieving both uniform coating and reduced splashing.
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 solution effectively suppresses overcoating and splashing at the edges of the steel strip by maintaining a consistent gas flow, allowing for a wider range of steel strip widths and reducing nozzle clogging, thus ensuring a uniform coating and increased operational efficiency.
Implementation Method 1
The gas outlet and the gas flow passageway have the same width, thereby the contracted flow of the gas does not produce vortexes
Implementation Method 2
left and right rectification pieces extending from respective gas outlet side ends of the left and right blocking members toward the partition wall are disposed, with a gas flow passageway formed between the left and right rectification pieces
Implementation Method 3
gas is sprayed onto an unsolidified plated surface of the steel strip after immersion so as to adjust the amount of attached molten metal
Implementation Method 4
spraying gas out of the gas outlet onto the steel strip linearly across one end to the other in the width direction of the steel strip, the molten metal on the surface of the steel strip is removed
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Provided is a gas wiping device having a gas wiping nozzle for adjusting the amount of molten metal for plating that becomes attached to a surface of a steel strip, by spraying a gas onto the surface, the gas wiping device having an excellent effect of suppressing overcoating or splashing at width-direction edges of the steel strip. A gas wiping nozzle 1 is provided with: a slit 1a' extending along a width direction of a steel strip K for blowing a gas out of a hollow; and gas introducing openings 1e for introducing the gas into the hollow. The slit 1a' is provided with slidable left and right blocking members 2, 2 for blocking left and right areas of the slit, with a gas outlet 1a formed between the blocking members 2, 2. In the hollow, left and right rectification pieces 1c, 1c are disposed, extending from gas outlet side ends 2a, 2a of the respective left and right blocking members 2, 2 toward a partition wall 1d. Between the left and right rectification pieces 1c, 1c, a gas flow passageway GR is formed. The gas outlet 1a and the gas flow passageway GR have the same width.