GB2139743A

GB2139743A - Metallurgical vessel

Info

Publication number: GB2139743A
Application number: GB08410347A
Authority: GB
Inventors: Siegfried Oppenauer; Gunter Poferl; Horst Wirth
Original assignee: Voestalpine AG
Current assignee: Voestalpine AG
Priority date: 1983-05-06
Filing date: 1984-04-19
Publication date: 1984-11-14
Also published as: BE899581A; MX168112B; KR840008920A; DE3414332A1; PT78522B; ES8503723A1; FR2545392A1; SE8402045D0; ZA843337B; ATA167183A; GB2139743B; GB8410347D0; PT78522A; NL8401426A; JPS59215413A; LU85343A1; AT377008B; SE8402045L; ES532151A0

Abstract

A metallurgical vessel (1) for molten metals includes a plurality of gas-permeable bricks (4,4',4'',...) or nozzles arranged in its wall. Each brick or each nozzle is connected to a common main feed (5) by an individual feed (6,6',6'',...) equipped with a gas flowmeter (7) followed by a control valve (8) to control the flow rate. The arrangement may be utilised to feed the bricks or nozzles differentially according to a preset programme and also to detect defective bricks or nozzles. <IMAGE>

Description

SPECIFICATION Improvements in or relating to a metallurgical vessel for molten metals The invention relates to a metallurgical vessel for molten metals, in particular a steelworks converter, comprising a plurality of gas-permeable bricks or nozzles arranged in its wall, preferably in its bottom, each brickoreach nozzle being connected to a common main feed by means of an individual feed.

It is known (South African patent No. 81 8089) to provide gas-permeable bricks arranged in the bottom of a converterwith a gasforthe purposeofflushing the melt present in the converter, wherein the gas flows through the melt after having left the bricks.

Such bricks may be supplied with natural gas also to heat the converter. A converter whose bottom is provided with nozzles for introducing a gas into the interior ofthe vessel is, for instance, known from German Offenlegungsschrift No. 23 46 087. With such a converter, a pressure control valve is provided to control the gas in the main feed. Since, in this case, onlythe overall amount offlush gas is controllable, unequal amounts of gas will emerge per brick or nozzle dueto the varying conditions of gas-permeable bricks or nozzles, which may be obstructed by slag, cracked or covered by slag flown in behind them, because the gas always chooses the way of least resistance. Furthermore, there is the danger that, in case of an inadmissible pressure increase at an obstructed brick, part of thins brick may chip off.

The invention aims at avoiding these disadvantages and difficulties and has as its object to provide a metallurgical vessel of the initially defined kind, in which a damageto a brick or nozzle on account of an excessive pressure influence is prevented, with which there is the possibility of recognizing a defective brick or nozzle without operational interruption, and which, furthermore, allows for the feeding of gas to individual bricks or nozzles non-uniformly according to a preset program.

This object is achieved according to the invention in each individual feed is equipped with a gas flowmeter followed by a control valve to control the flow rate.

Suitably, a pressure limiting valve is arranged after the control valve, whereby an excessive pressure is automatically prevented. According to a preferred embodiment, a control circuit is provided to control the control valve, whose controlled variable istheflow rate through an individual feed, whose reference input is the set point for the flow rate and whose manipulated variable is the control valve position.

Advantageously, a flow control is provided for each brick or each nozzle, whose set point is constituted by an overall-set-point emitterfor all ofthe bricks or nozzles and by an individual-set-point emitter for each individual brick or nozzle.

The invention will now be explained in more detail with reference to the drawing, which schematically illustrates the control of an individual gas-permeable brick incorporated in the bottom of a converter.

By 1 a schematically illustrated converter is denoted, whose steel shell 2 inwardly is provided with a refractory lining 3. In the refractory lining 3, several gas-permeable bricks 4, 4', 4", ... are incorporated in orderto supply heating gas and/orflush gas. Each of the bricks 4, 4', 4", ... is fed with gas by an individual feed 6,6', 6",... branching off a main feed 5, wherein, in the drawing, one individual feed 6for one ofthe bricks 4 is illustrated in detail.

After branching offthe main feed 5, a flowmeter 7 is provided inthe individual feed 6to detecttheset point X of the gas amount flowing through the individual feed 6. In the flow direction, the flowmeter 7 is followed by a control valve 8. Between the latter and the gas-permeable brick 4, a conduit9 branches off the individual feed and enters into the open air, in which a pressure limiting valve 10 is installed.

Two set points Wa, W2 are entered into a flow control 11 illustrated in broken lines, by means of set point emitters 12 and 13, i.e. an overall-set-pointW1 of the flow rate for all of the gas-permeable bricks 4, 4', 4", . . . arranged in the bottom of the converter 1 by an overall-set-point emitter 12, and an individual-set pointW2forthe gas-permeable brick4, 4', 4", . .

connected to the respective individual feed 6, 6', 6", ... by means of an individual-set-point emitter 13.

The arrangementfunctions in the following manner: The set pointX oftheflow rate detected by the flowmeter 7 serves to control the position of the control valve 8, the manipulated variable Y emitted by the flow control 11 and controlling the control valve 8 being controlled in dependence on the overall-set point W1 and the individual-set-pointW2. The pressure limiting valve 10 prevents the destruction of the gas-permeable bricks in case of an operating error.

In order to realize, for instance, a special flushing program with different feedings ofthe bricks 4,4', 4", ..., there is the possibility to control the set points in dependence on the process running in the converter 1, by means of a process control computer. Iftoo low a flow rate is detected at any of the gas-permeable bricks 4, 4', 4", . . ., there isthe chance of finding out this brick by means of a separate display. The individual feed 6, 6', 6",... to this defective brick 4, 4', 4",... may then be interrupted.

Afurtheradvantage ofthe described arrangement is to be seen in that the gas amount per gas-permeable brick 4, 4', 4",... may be kept constant irrespective of the condition ofthe brick.

The invention is not limited to the embodiment illustrated in the drawing, but may be modified in various aspects. For instance, it is possible to provide the metallurgical vessel with nozzles instead of the gas-permeable porous bricks, through which nozzles gas may be injected into the interior of the metallurgical vessel. In this case, an individual feed is led to each nozzle, comprising a gasflowmeterfollowed bya control valve to control the flow rate.

1. In a metallurgical vessel for molten metals, such as a steelworks converter, ofthetype including a vessel wall, a plurality of gas-permeable means arranged in said vessel wall, an individual feed provided for each of said gas-permeable means, and a common main feed to which said individual feed is connected, the improvement which comprises a gas flowmeter provided for each individual feed and a

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in or relating to a metallurgical vessel for molten metals The invention relates to a metallurgical vessel for molten metals, in particular a steelworks converter, comprising a plurality of gas-permeable bricks or nozzles arranged in its wall, preferably in its bottom, each brickoreach nozzle being connected to a common main feed by means of an individual feed. It is known (South African patent No. 81 8089) to provide gas-permeable bricks arranged in the bottom of a converterwith a gasforthe purposeofflushing the melt present in the converter, wherein the gas flows through the melt after having left the bricks. Such bricks may be supplied with natural gas also to heat the converter. A converter whose bottom is provided with nozzles for introducing a gas into the interior ofthe vessel is, for instance, known from German Offenlegungsschrift No. 23 46 087. With such a converter, a pressure control valve is provided to control the gas in the main feed. Since, in this case, onlythe overall amount offlush gas is controllable, unequal amounts of gas will emerge per brick or nozzle dueto the varying conditions of gas-permeable bricks or nozzles, which may be obstructed by slag, cracked or covered by slag flown in behind them, because the gas always chooses the way of least resistance. Furthermore, there is the danger that, in case of an inadmissible pressure increase at an obstructed brick, part of thins brick may chip off. The invention aims at avoiding these disadvantages and difficulties and has as its object to provide a metallurgical vessel of the initially defined kind, in which a damageto a brick or nozzle on account of an excessive pressure influence is prevented, with which there is the possibility of recognizing a defective brick or nozzle without operational interruption, and which, furthermore, allows for the feeding of gas to individual bricks or nozzles non-uniformly according to a preset program. This object is achieved according to the invention in each individual feed is equipped with a gas flowmeter followed by a control valve to control the flow rate. Suitably, a pressure limiting valve is arranged after the control valve, whereby an excessive pressure is automatically prevented. According to a preferred embodiment, a control circuit is provided to control the control valve, whose controlled variable istheflow rate through an individual feed, whose reference input is the set point for the flow rate and whose manipulated variable is the control valve position. Advantageously, a flow control is provided for each brick or each nozzle, whose set point is constituted by an overall-set-point emitterfor all ofthe bricks or nozzles and by an individual-set-point emitter for each individual brick or nozzle. The invention will now be explained in more detail with reference to the drawing, which schematically illustrates the control of an individual gas-permeable brick incorporated in the bottom of a converter. By 1 a schematically illustrated converter is denoted, whose steel shell 2 inwardly is provided with a refractory lining 3. In the refractory lining 3, several gas-permeable bricks 4, 4', 4", ... are incorporated in orderto supply heating gas and/orflush gas. Each of the bricks 4, 4', 4", ... is fed with gas by an individual feed 6,6', 6",... branching off a main feed 5, wherein, in the drawing, one individual feed 6for one ofthe bricks 4 is illustrated in detail. After branching offthe main feed 5, a flowmeter 7 is provided inthe individual feed 6to detecttheset point X of the gas amount flowing through the individual feed 6. In the flow direction, the flowmeter 7 is followed by a control valve 8. Between the latter and the gas-permeable brick 4, a conduit9 branches off the individual feed and enters into the open air, in which a pressure limiting valve 10 is installed. Two set points Wa, W2 are entered into a flow control 11 illustrated in broken lines, by means of set point emitters 12 and 13, i.e. an overall-set-pointW1 of the flow rate for all of the gas-permeable bricks 4, 4', 4", . . . arranged in the bottom of the converter 1 by an overall-set-point emitter 12, and an individual-set pointW2forthe gas-permeable brick4, 4', 4", . . connected to the respective individual feed 6, 6', 6", ... by means of an individual-set-point emitter 13. The arrangementfunctions in the following manner: The set pointX oftheflow rate detected by the flowmeter 7 serves to control the position of the control valve 8, the manipulated variable Y emitted by the flow control 11 and controlling the control valve 8 being controlled in dependence on the overall-set point W1 and the individual-set-pointW2. The pressure limiting valve 10 prevents the destruction of the gas-permeable bricks in case of an operating error. In order to realize, for instance, a special flushing program with different feedings ofthe bricks 4,4', 4", ..., there is the possibility to control the set points in dependence on the process running in the converter 1, by means of a process control computer. Iftoo low a flow rate is detected at any of the gas-permeable bricks 4, 4', 4", . . ., there isthe chance of finding out this brick by means of a separate display. The individual feed 6, 6', 6",... to this defective brick 4, 4', 4",... may then be interrupted. Afurtheradvantage ofthe described arrangement is to be seen in that the gas amount per gas-permeable brick 4, 4', 4",... may be kept constant irrespective of the condition ofthe brick. The invention is not limited to the embodiment illustrated in the drawing, but may be modified in various aspects. For instance, it is possible to provide the metallurgical vessel with nozzles instead of the gas-permeable porous bricks, through which nozzles gas may be injected into the interior of the metallurgical vessel. In this case, an individual feed is led to each nozzle, comprising a gasflowmeterfollowed bya control valve to control the flow rate. CLAIMS

1. In a metallurgical vessel for molten metals, such as a steelworks converter, ofthetype including a vessel wall, a plurality of gas-permeable means arranged in said vessel wall, an individual feed provided for each of said gas-permeable means, and a common main feed to which said individual feed is connected, the improvement which comprises a gas flowmeter provided for each individual feed and a controlvalvefollowing upon said gasflowmeter and adapted to control the flow rate.

2. Avessel as set forth in claim 1, wherein said vessel wall comprises a bottom and said gas-permeable means are provided in said bottom.

3. Avessel as set forth in claim 1 ,wherein said gas-permeable means are bricks.

4. A vessel as setforth in claim 1, wherein said gas-permeable means are nozzles.

5. A vessel as set forth in claim 1, furthercompris- ing a pressure limiting valve arranged aftersaid control valve.

6. A vessel as set forth in claim 1, wherein a control circuit is provided to control said control valve, said control circuit comprising a controlled variable being the flow rate through said individual feed, a reference input being a set point for said flow rate, and a manipulated variable being the position of said control valve.

7. A vessel as set forth in claim 1, further compris- ing an overall-set-point emitter provided forthe total of said gas-permeable means, an individual-set-point emitter provided for each of said gas-permeable means, and a flow control provided for each of said gas-permeable means to receive a set point constituted bysaid overall-set-pointemitterand one indi- vidual-set-point emitter.

8. A vessel substantially as hereinbefore described with reference to the accompanying drawing.