Pickling device and pickling pause operation method

Patent metadata

Field	Value
Publication number	US-10711353-B2
Application number	US-201715756699-A
Country	US
Kind code	B2
Filing date	Feb 22, 2017
Priority date	Apr 27, 2016
Publication date	Jul 14, 2020
Grant date	Jul 14, 2020

Abstract

To prevent over-pickling of a steel strip during pickling pause, and shorten the time required to switch between pickling operation and pickling pause, a pickling device includes: a pickling tank for storing acid solution and for pickling a steel strip by allowing the steel strip to travel therethrough while the steel strip is immersed in the acid solution; a heat exchanger for heating the acid solution in the pickling tank; a circulation tank for storing the acid solution, provided separately from the pickling tank; an acid-solution circulation unit configured to circulate the acid solution between the pickling tank and the acid-solution storage tank; and a control device configured to control the acid-solution circulation device to maintain a liquid level of the acid solution in the pickling tank at a level below a traveling height of the steel strip.

First claim

The invention claimed is:

1. A pickling device, comprising:
a pickling tank for storing acid solution and for pickling a steel strip by allowing the steel strip to travel therethrough while the steel strip is immersed in the acid solution;
a heating unit for heating the acid solution in the pickling tank;
an acid-solution storage tank for storing the acid solution, provided separately from the pickling tank;
an acid-solution circulation unit configured to circulate the acid solution between the pickling tank and the acid-solution storage tank; and
a liquid level adjustment unit configured to control the acid-solution circulation unit to maintain a liquid level of the acid solution in the pickling tank at a level below a traveling height of the steel strip,

wherein the liquid-level adjustment unit includes an inflow passage which connects to a drain port for the acid solution disposed on the pickling tank,
wherein the inflow passage has an inlet positioned below the traveling height of the steel strip and above the drain port, and
wherein the liquid-level adjustment unit is configured to allow the acid solution in the pickling tank to overflow from the inlet to maintain the liquid level of the acid solution in the pickling tank at the level of the inlet,
wherein the inflow passage is a dam which surrounds the drain port for the acid solution.

2. The pickling device according to claim 1 ,
wherein the acid-solution circulation unit includes a flow passage between a drain port of the pickling tank and the acid-solution storage tank, a flow passage between a supply port of the pickling tank and the acid-solution storage tank, an opening-and-closing valve disposed in at least one of the two flow passages, and a pump disposed in at least the other one of the two flow passages, and
wherein the liquid-level adjustment unit is configured to control opening and closing of the opening-and-closing valve and operation of the pump.

3. The pickling device according to claim 1 ,
wherein the heating unit is a heat exchanger, and
wherein the liquid-level adjustment unit is configured to adjust a liquid level of the acid solution so that at least a part of the heat exchanger is immersed in the acid solution.

4. A pickling device, comprising:
a pickling tank for storing acid solution and for pickling a steel strip by allowing the steel strip to travel therethrough while the steel strip is immersed in the acid solution;
a heating unit for heating the acid solution in the pickling tank;
an acid-solution storage tank for storing the acid solution, provided separately from the pickling tank;
an acid-solution circulation unit configured to circulate the acid solution between the pickling tank and the acid-solution storage tank; and
a liquid level adjustment unit configured to control the acid-solution circulation unit to maintain a liquid level of the acid solution in the pickling tank at a level below a traveling height of the steel strip,
wherein the acid-solution circulation unit includes a flow passage between a drain port of the pickling tank and the acid-solution storage tank, a flow passage between a supply port of the pickling tank and the acid-solution storage tank, an opening-and-closing valve disposed in at least one of the two flow passages, and a pump disposed in at least the other one of the two flow passages,

wherein the liquid-level adjustment unit is configured to control opening and closing of the opening-and-closing valve and operation of the pump, and

wherein the liquid-level adjustment unit includes a liquid-level measurement unit for measuring a liquid level of the acid solution, and is configured to control opening and closing of the opening-and-closing valve and operation of the pump on the basis of the liquid level of the acid solution measured by the liquid-level measurement unit.

5. A method of operating, during pickling pause, a pickling device which comprises: a pickling tank for pickling a steel strip by allowing the steel strip to travel therethrough while the steel strip is immersed in acid solution; a heating unit for heating the acid solution in the pickling tank; a circulation unit configured to circulate the acid solution between an acid-solution storage tank for storing the acid solution and the pickling tank; and a liquid level adjustment unit configured to control the acid-solution circulation unit to adjust a liquid level of the acid solution in the pickling tank, the liquid-level adjustment unit including an inflow passage which connects to a drain port for the acid solution disposed on the pickling tank, the inflow passage being a dam which surrounds the drain port for the acid solution and having an inlet positioned below a traveling height of the steel strip and above the drain port, the method comprising:
during pickling pause of the steel strip, circulating the acid solution between the acid-solution storage tank and the pickling tank with the circulation unit while maintaining a liquid level of the acid solution inside the pickling tank at a level of the inlet by allowing the acid solution in the pickling tank to overflow from the inlet by means of the liquid level adjustment unit, and heating the circulating acid solution with the heating unit inside the pickling tank.

Assignees

• Primetals Tech Japan Ltd

Inventors

• Nakatsuka Ryusuke
• Tsuji Kosei
• Suemori Hideaki
• Nakamura Koichi

Classifications

• C23G3/027

  Associated apparatus, e.g. for pretreating or after-treating · CPC title

• C23G3/021 Primary

  by dipping · CPC title

• C23G3/025

  Details of the apparatus, e.g. linings or sealing means · CPC title

• C23G1/08

  Iron or steel · CPC title