Hot-dip Galvanizing Apparatus Draining Device for Roll Pick-up

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Solution Overview

Problem

The challenge arises when switching between producing high tensile strength and normal strength steel sheets, as the humidified gas system's condensation and accumulation lead to roll pick-up and poor coating appearance due to the spread of water and excessive humidified gas in the pipes, causing non-coating issues during hot-dip galvanizing.

Innovation Solution

The method involves a continuous hot-dip galvanizing apparatus with a draining device to prevent condensation and accumulation of humidified gas by controlling the water circulation and gas distribution, ensuring that dry gas is not flowing through the humidifying device when not in use, and restarting water circulation when switching to high tensile strength production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If humidified gas is supplied to the soaking zone during high tensile strength steel sheet production, then coating appearance is improved, but condensation and accumulation of humidified gas occur in pipes during non-use, causing roll pick-up and non-coating

Engineering Contradiction:
Improvecoating appearanceVSAvoidprocess stability during switching
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The system performs preliminary drainage of water from the humidifying device before switching to normal strength steel sheet production. This preliminary action prevents condensation and accumulation of humidified gas in pipes during non-use, thereby avoiding roll pick-up and non-coating defects when switching between product types.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system discards water from the humidifying device through drainage when humidified gas is not in use. This prevents harmful accumulation of water and excessive humidified gas in the pipes, maintaining system reliability during operational switching while preserving the ability to produce high tensile strength steel sheets with excellent coating appearance when needed.

Inventive Principle:
Principle #34Discarding and recovering

2Reliability

If water circulation is continued during non-use of humidified gas, then condensation is prevented, but excessive humidified gas accumulates in pipes causing roll pick-up

Engineering Contradiction:
Improvecondensation preventionVSAvoidexcessive humidified gas accumulation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system discards water from the humidifying device through drainage when humidified gas is not in use. This prevents harmful accumulation of water and excessive humidified gas in the pipes, maintaining system reliability during operational switching while preserving the ability to produce high tensile strength steel sheets with excellent coating appearance when needed.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The system implements periodic drainage operations based on operational state changes. Water circulation and drainage are activated or deactivated according to whether humidified gas is currently in use, creating a periodic action pattern that prevents both condensation during use and accumulation during non-use.

Inventive Principle:
Principle #19Periodic action

3Ease of operation

If humidified gas system is stopped during non-use, then operational simplicity is improved, but water spreads and condenses in pipes causing roll pick-up

Engineering Contradiction:
Improveoperational simplicityVSAvoidroll pick-up from condensation
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The system discards water from the humidifying device through drainage when humidified gas is not in use. This prevents harmful accumulation of water and excessive humidified gas in the pipes, maintaining system reliability during operational switching while preserving the ability to produce high tensile strength steel sheets with excellent coating appearance when needed.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The system extracts water from the humidifying device through drainage when humidified gas is not in use. This removes the source of condensation and harmful humidified gas accumulation, preventing roll pick-up while maintaining operational simplicity during non-use periods.

Inventive Principle:
Principle #2Taking out (Extraction)

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 approach effectively inhibits roll pick-up in the soaking zone and ensures a favorable coating appearance by preventing condensation and excessive humidified gas from entering the soaking zone during operational state changes.

Implementation Method 1

a humidifying device 50 for humidifying the dry gas

Methodology Applied
Scientific EffectHumidification: Absorption (physical)

Implementation Method 2

a draining device 80 for draining water from a space at an outside of the vapor permeable membranes in the module when mixed gas is not supplied to the soaking zone

Methodology Applied
Scientific EffectGravity drainage: Gravitation

Implementation Method 3

vapor permeable membranes 51 disposed in the module 52

Methodology Applied
Scientific EffectVapor permeation: Permeation

Data Source

PatentEP3276037B1Method of manufacturing a hot-dip galvanized steel sheet
Publication Date: 2021.04.07 JFE STEEL CORP
  • EP3276037B1 patent drawingFigure 1
  • EP3276037B1 patent drawingFigure 2
  • EP3276037B1 patent drawingFigure 3

AI summary

Provided is a continuous hot-dip galvanizing apparatus that can inhibit roll pick-up in a soaking zone caused by condensation or the like in a humidified gas pipe, and with which favorable coating appearance can be obtained. The continuous hot-dip galvanizing apparatus includes an annealing furnace in which a heating zone, a soaking zone, and a cooling zone are arranged in this order, and a hot-dip galvanizing line adjacent to the cooling zone. Gases supplied to the soaking zone (12) are: mixed gas obtained by mixing gas that is humidified by a humidifying device (50) and gas that is not humidified by the humidifying device; and dry gas that is not humidified by the humidifying device. The continuous hot-dip galvanizing apparatus includes a draining device (80) for draining circulating water from the humidifying device (50) when the mixed gas is not supplied to the soaking zone (12).