CA1041770A - Kinetic energy monitor - Google Patents
Kinetic energy monitorInfo
- Publication number
- CA1041770A CA1041770A CA215,754A CA215754A CA1041770A CA 1041770 A CA1041770 A CA 1041770A CA 215754 A CA215754 A CA 215754A CA 1041770 A CA1041770 A CA 1041770A
- Authority
- CA
- Canada
- Prior art keywords
- vessel
- medium
- agitation
- oxygen
- weight
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G3/00—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances
- G01G3/12—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances wherein the weighing element is in the form of a solid body stressed by pressure or tension during weighing
- G01G3/14—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances wherein the weighing element is in the form of a solid body stressed by pressure or tension during weighing measuring variations of electrical resistance
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G3/00—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances
- G01G3/12—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances wherein the weighing element is in the form of a solid body stressed by pressure or tension during weighing
- G01G3/14—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances wherein the weighing element is in the form of a solid body stressed by pressure or tension during weighing measuring variations of electrical resistance
- G01G3/1402—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
- G01G3/1406—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports combined with special measuring circuits
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
- Preliminary Treatment Of Fibers (AREA)
- Food Preservation Except Freezing, Refrigeration, And Drying (AREA)
Abstract
ABSTRACT
Apparatus for controlling the treatment of a medium in a vessel, comprising means for monitoring the weight of the contents of the vessel and producing an electrical signal indicative of the apparent variations in weight of the contents of the vessel, means for extracting from the electrical signal that part of the signal produced by agitation of the medium in the vessel, means for recording said part of the signal, and calibration means correlating the characteristics of the medium, time, and the amount of agitation in the medium whereby the future progress of the treatment can be controlled. When the medium whose treatment is to be controlled is the nolten charge in a steelmaking process involving the injection of oxygen, the part of the signal produced by the agitation of the molten charge is a frequency band with the range 0.05 Hz to 5.0 Hz.
Apparatus for controlling the treatment of a medium in a vessel, comprising means for monitoring the weight of the contents of the vessel and producing an electrical signal indicative of the apparent variations in weight of the contents of the vessel, means for extracting from the electrical signal that part of the signal produced by agitation of the medium in the vessel, means for recording said part of the signal, and calibration means correlating the characteristics of the medium, time, and the amount of agitation in the medium whereby the future progress of the treatment can be controlled. When the medium whose treatment is to be controlled is the nolten charge in a steelmaking process involving the injection of oxygen, the part of the signal produced by the agitation of the molten charge is a frequency band with the range 0.05 Hz to 5.0 Hz.
Description
'77V
~his invention relates to a method of, and apparatus ~or3 controlling the treatment of a medium i~ a ves~el, and ::
has an important application to the treatment of the molten charge in a steelmaking process involving the injection of oxygen.
In a wide variety of industrial processes in which a medium is treated in a vessel, and ranging, for example~
~rom steelmaking to brewing and winemaking, the control of the process to bring it to a satisfactory conclusion depends on the physical and/or chemical changes which take place in t~e medium with the elapse of time~ It is a disadvantage o~ many such processes that the environment, such as the high temperature in steelmaking, or the need to avoid contaminating ~.. . .
the medium, as in brewing or winemaking3 make it difficult to ascertain the physical and/or chemical changes which are taking .. ..
place in the medium, and therefore ~he control of the process and in particular choice o~ the optimum time for its termination, presents considerable di~ficulty.
It is an object of this in~ention to provide a process and apparatus which mitigates the abo~e~mentioned dif~icultyO ^-~ccording to one aspect of the present invention ..
apparatus ~or controlling the trea~ment o~ a medium in a ~essel, comprises means for monito~ing the weight o~ the con~ents of the vessel and producing an electrical signal , ',
~his invention relates to a method of, and apparatus ~or3 controlling the treatment of a medium i~ a ves~el, and ::
has an important application to the treatment of the molten charge in a steelmaking process involving the injection of oxygen.
In a wide variety of industrial processes in which a medium is treated in a vessel, and ranging, for example~
~rom steelmaking to brewing and winemaking, the control of the process to bring it to a satisfactory conclusion depends on the physical and/or chemical changes which take place in t~e medium with the elapse of time~ It is a disadvantage o~ many such processes that the environment, such as the high temperature in steelmaking, or the need to avoid contaminating ~.. . .
the medium, as in brewing or winemaking3 make it difficult to ascertain the physical and/or chemical changes which are taking .. ..
place in the medium, and therefore ~he control of the process and in particular choice o~ the optimum time for its termination, presents considerable di~ficulty.
It is an object of this in~ention to provide a process and apparatus which mitigates the abo~e~mentioned dif~icultyO ^-~ccording to one aspect of the present invention ..
apparatus ~or controlling the trea~ment o~ a medium in a ~essel, comprises means for monito~ing the weight o~ the con~ents of the vessel and producing an electrical signal , ',
-2-,.
~'" ' ~ .
'''" " ''`
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indicative of the apparent -variations in weight of the contents of the vessel, means for extracting from the electrical signal that part of the signal produced by agitation of the medium in the vessel, means for record-ing said part of the signal, and calibration means correlating the character~
istics of the medium, time, and the amount of agitation in the medium where-by the progress of the treatment can be controlled.
According to another aspect of the invention a method of control-ling the treatment of a medium in a vessel, comprises the steps of monitor-ing the weight of the contents of the vessel and producing an electrical signal indicative of the apparent variations in weight of the contents of the vessel, extracting from the electrical signal that part of the signal produced by agitation of the medium in the vessel, recording said part of the signal, and thereafter controlling the progress of the treatment of the medium by comparing the record with a previously established relation-ship correlating characteristics of the medium, time and the amount of --:
agitation in the medium. ~, When the medium whose treatment is to be controlled is the molten :
charge in a steelmaking process involving the injection of oxygen, the part of the signal produced by agitation of the medium in the vessel will usually be in a frequency band within the range 0.05 Hz to 5.0 Hz and is preferably within the range 0.1 Hz to 1.0 Hz.
~ Preferably the weight of the contents of the vessel ,., :: .
~04~Lq7~
is monitored by a plurality o~ force measuring tranæducers : :
which may be incorporated in pedestals supporting the vessel~
Each force measuring transducer may comprise a steel billet to which is bonded a foil strain ~auge sensitive to tensile or compressi~e load, and the foil strain gauges may be connected in an electrical bridge circuit arranged to produce the electrical signal indicati~e of the apparent variations in weight of the contents of the vessel.
The in~ention will now be described, b~ way o~
example~ with reference to the accompanying drawings i~
which~
Figure 1 is a schematic perspecti~e view of a steelmaking furnaca embodying the invention;
~ igure 2 is a typical weight chan~e record made duri~g a refining process of ox~gen steelmaking carried out in the ~urnace shown in Fi~ure 1, ~ igure 3 is a typical level of agitation record correspondîng to the weight change record shown i~
~ re 2; and ~iæure 4 is a side elevation of a force measuring:
transducer shown in Figure 1~
Referring to the drawings, the furnace comprises a refractory vessel 1 having a~ opening 2 at the top throu~h which scrap iro~. or scrap ~teel may be recei~ed, and throu~h !" ',' which molten metal ~rom the blast ~urnace ma~ be added to the scrap metal. The vessel 1 is provided with two trunnio~s 3 each of which is supported in a trunnion bearing 4 to permit :
the vessel 1 to be ~ilted to discharge the molten metal. Each trunDion bearing 4 is supported on a pedestal 5 incorporating ;,', ''.
- 4 ~
"' ', ~:
'. .
-eight force measuring transducers 6 arranged to monitor the weight of the vessel 1. As shown in Flgure 4, each ~orce measuring transducer 6 comprises a steel billet 1 to which is intimatel-y bonded a plurality o~ foil strai~
gauges 26 sensitive to tensile or compressive load induced by the weight of the vessel l. A lance 7 extendin~ through the opening 2 at the top o~ the ves~el is arran~ed to inject oxyge~ into the molten charge.
~he strain gauges 26 o~ the transducers 6 are connected together to form a Wheatstone Brid~e circuit to which an energising voltage is applied b~ two amplifiers 8 ana 9. When a load is applied to the transducers 6 a millivolt QUtpUt signal directly proportional to the applied load is produced by the Wheatstone Bridge and is passed to the amplifiers 8 and 9. Output signals produced by the amplifiers 8 and 9 are summated in a summi~g amplifier lO~ the output o~ which is applied to an autotare or automatic zero unit 11 h~ving a 0 to 5 volt ` "
d~c. output signal which xepresents a weight of 0 to 200 tons. ~he output of the autotare unit 11 is passed to a di~erential scaling amplifier 12 havi~g a 0 to ~ 5 volt d.c. output which represents a weight of 0 to + ~0 tons.
~he d.c. output signal from the scaling amplifier 12, which i~ indicative of the apparent variations in weight of the contents of the ~essel l, is applied to a weight recorder 13 which produces a change of weight trace 14 as shown in Figure 2.
~he d.c. output signal from the scaling ampli~ier 12 - 5 - ;
7~7C~
is also applied to an agitation monitor 15 which is responsive ~ :
to that part o~ the d.c. output s:ignal produced by the agitation of the contents of t~e vessel 1 and which ~or molten steel and slag in the ~essel 1 has been found to be a frequency band within the range 0 a5 Hz to 5.0 Hz. ~he output signal from the agitation monitor 15 is passed to an agitation recorder 17 which produces a trace 18 as shown in ~igure indicative of the agitation o~ the ~olte~ contents o~ the vessel 1. ~ . :
In carrying out the steelmaking process the output of the scaling amplifier 12 is adjusted so that it reads zero as indicated at point 19 on trace 14, and oxygen is then injected into the molten char~e by lance 7. Fluxes are then :
introduced into the vessel 1, causing the recorded weight to i~crease towards a value indicated at poin~ 22~ The injection o~ the oxy~en causes carbon to be removed ~rom the .~-molten charge a~d leave the vessel 1 as either carbon monoxide or carbon dioxide which tends to reduce the recorded weight, while silicon and then manganese ~nd phosphorus are removed . 20 from the molten charge and appear in the slag, mainly as oxides~
which tend to increase the recorded weight. During this time ~ :
there may be periods when the recorded weight of the furnace contents tends to remain substantiall~ constant as indicated b~ i the portion of trace 14 between the points 20 and 21. ..
~ubsequently, a small amount of carbon is oxidised and iron .', ' ' ' '' ~
~`
q~
oxides build up in the slag so that the recorded weight again begins to increase towards a value indicated at the poin-t 22 on the trace 140 Finally, there is a secondary decarburiza-tion of the molten charge which brings down the carbon level to the finishing level and progressively reduces the recorded weight as indicated by the portion o~ the trace 14 between points 22 and 23.
During this period of secondar~ decarburization -the change of weight trace 14 tends -to fluctuate rapidly as indicated by the peaks 24 and troughs 25, and it has been fo~md that these fluctuations are indicative of the level of agitation of the liquid contents of the vessel 1 and are also indicative of the physical and/or chemical chan~es which are taking place at this time. ~herefore, by extracting that part of the output signal of the scaling amplifier 12 which produces the fluctuation and applying it to the recorder 17, a trace 18 as show~ in Figure 3 is obtained which is representative of the agitation in the liquid contents cf the vessel 1. For the fluctuations shown in the trace 14 it was found that the part of the output signal of the scaling amplifier 12 which was indicative of the level of agitation was a frequency band within the range Ool Hz to 1.0 Hz~
~ he trace 18 produced by the recorder 17 is used in the following manner to control the activity o~ the molten metal in the vessel 1. When oxygen is first in~ected into the molten charge, the tip of the lance 7 is positioned about .. ..
~04~ 70 100 inches above the surface of the molten charge~ lypically, with a mol-terl charge of 150 tons, o~ygen is inàected into the - ~ -molten charge at a substantially constant rate of 10~000 cubic ~eet per minute. After a period o~ one minute the tip of the lance 7 is gradually lowerecL to a height of 75 inches above the surface of the molten charge, and ~our minutes later the tip of the lance 7 is brought to a height o~ 50 inches above the surface o~ the molten char~eO ~inally, after a further two minutes the tip of the lance 7 is brought to a height o~
39 inches above the surface of the molten charge and remains at this height until the end of the steelmaking process.
If the tip of the lance 7 is lowered too soon the slag beco~es very viscous and i~ the lowering of the tip of the lance is delayed too lon~ the slag becomes foamy and may slop o~er the sides of the vessel 1.
~ he time at which the tip of the lance should ~e lowered to its ~inal powition above the surface o~ the molten charge can be ascertained from the trace 14 in ~igure 2 which at this time be~ins to fluctuate as indicated at point 27.
he time at which the fluctuatio~s co~mence can be more reaail~ ascertai~ed from the trace 18 which has a substantially linear rise at this time. ~here~ore, by preparing a calibration chart w~ich, for the vessel 1 with 150 ton molte~
charge and co~stant rate o~ oxygen injection as described above, consists of an idealized curve o~ substa~tially the same shape , '', . .
la~ o as trace 187 the point 28 on the trace 18 at which the lance 7 should be lowered to its final height can readil~ be ascertained. In practice the optimum position ~or the poi~t 28 has been found to be midway along the linear portion o~ the trace 180 When the secondary decarburization nears completion the fluctuations o~ the trace 14 diminish in amplitude as can be seen from the portion of the trace near to the point 23, and it is at this time that the injection of oxygen into the molten charge needs to be terminate~ by raising the lance 7.
The optimum time for te~minating the process can be more readily ascertai~ed ~rom the trace 18 which has a substantially linear fall at this time. In practi~e it has been found that the optimum time to termina~e the injection of o~ygen corresponds tc a point 29 midway along the linear portion of the trace 18~
~lthough the rate of oxygen i~jection was kepk substantially cons~ant in the process described above9 calibration charts can also be prepared to cover predetex~ined variations in the rate o~ oxygen injeGtion during the process, provided that the predetermined vaxiation in oxygen injection is repeated faithfully when the process is being controlled.
Moreover, although the oxygen was inaected by means of a lance 7 in the process described above, vessels employing bottom blowing o~ oxygen utilizing a valve 31 in the bottom of the vessel 1 are also suitable ~or caxrying out khe process~
_9_ .. . .
~o~
It is envisaged that t:he method and apparatus o~ ~
the invention will fi~d use in man~ other industrial pxocesses .: . :
in which the treatment of a medium in a vessel produces agitation of the medium which is related to the physical ,~
and/or chemical changes taking place in the medium.
In particular it is thought that the method a~d apparatus o~
the in~ention will ~ind use in brewing and winemaking processes wherein the additio~ of ~east to a liquid medium :-results in fermentation accompanied by agitation of the liquid which can be monitored, recorded and used to control the progress o~ the process in a manner similar to that described aboveO
~ ': ' !
-10~
~'" ' ~ .
'''" " ''`
~4il~
indicative of the apparent -variations in weight of the contents of the vessel, means for extracting from the electrical signal that part of the signal produced by agitation of the medium in the vessel, means for record-ing said part of the signal, and calibration means correlating the character~
istics of the medium, time, and the amount of agitation in the medium where-by the progress of the treatment can be controlled.
According to another aspect of the invention a method of control-ling the treatment of a medium in a vessel, comprises the steps of monitor-ing the weight of the contents of the vessel and producing an electrical signal indicative of the apparent variations in weight of the contents of the vessel, extracting from the electrical signal that part of the signal produced by agitation of the medium in the vessel, recording said part of the signal, and thereafter controlling the progress of the treatment of the medium by comparing the record with a previously established relation-ship correlating characteristics of the medium, time and the amount of --:
agitation in the medium. ~, When the medium whose treatment is to be controlled is the molten :
charge in a steelmaking process involving the injection of oxygen, the part of the signal produced by agitation of the medium in the vessel will usually be in a frequency band within the range 0.05 Hz to 5.0 Hz and is preferably within the range 0.1 Hz to 1.0 Hz.
~ Preferably the weight of the contents of the vessel ,., :: .
~04~Lq7~
is monitored by a plurality o~ force measuring tranæducers : :
which may be incorporated in pedestals supporting the vessel~
Each force measuring transducer may comprise a steel billet to which is bonded a foil strain ~auge sensitive to tensile or compressi~e load, and the foil strain gauges may be connected in an electrical bridge circuit arranged to produce the electrical signal indicati~e of the apparent variations in weight of the contents of the vessel.
The in~ention will now be described, b~ way o~
example~ with reference to the accompanying drawings i~
which~
Figure 1 is a schematic perspecti~e view of a steelmaking furnaca embodying the invention;
~ igure 2 is a typical weight chan~e record made duri~g a refining process of ox~gen steelmaking carried out in the ~urnace shown in Fi~ure 1, ~ igure 3 is a typical level of agitation record correspondîng to the weight change record shown i~
~ re 2; and ~iæure 4 is a side elevation of a force measuring:
transducer shown in Figure 1~
Referring to the drawings, the furnace comprises a refractory vessel 1 having a~ opening 2 at the top throu~h which scrap iro~. or scrap ~teel may be recei~ed, and throu~h !" ',' which molten metal ~rom the blast ~urnace ma~ be added to the scrap metal. The vessel 1 is provided with two trunnio~s 3 each of which is supported in a trunnion bearing 4 to permit :
the vessel 1 to be ~ilted to discharge the molten metal. Each trunDion bearing 4 is supported on a pedestal 5 incorporating ;,', ''.
- 4 ~
"' ', ~:
'. .
-eight force measuring transducers 6 arranged to monitor the weight of the vessel 1. As shown in Flgure 4, each ~orce measuring transducer 6 comprises a steel billet 1 to which is intimatel-y bonded a plurality o~ foil strai~
gauges 26 sensitive to tensile or compressive load induced by the weight of the vessel l. A lance 7 extendin~ through the opening 2 at the top o~ the ves~el is arran~ed to inject oxyge~ into the molten charge.
~he strain gauges 26 o~ the transducers 6 are connected together to form a Wheatstone Brid~e circuit to which an energising voltage is applied b~ two amplifiers 8 ana 9. When a load is applied to the transducers 6 a millivolt QUtpUt signal directly proportional to the applied load is produced by the Wheatstone Bridge and is passed to the amplifiers 8 and 9. Output signals produced by the amplifiers 8 and 9 are summated in a summi~g amplifier lO~ the output o~ which is applied to an autotare or automatic zero unit 11 h~ving a 0 to 5 volt ` "
d~c. output signal which xepresents a weight of 0 to 200 tons. ~he output of the autotare unit 11 is passed to a di~erential scaling amplifier 12 havi~g a 0 to ~ 5 volt d.c. output which represents a weight of 0 to + ~0 tons.
~he d.c. output signal from the scaling amplifier 12, which i~ indicative of the apparent variations in weight of the contents of the ~essel l, is applied to a weight recorder 13 which produces a change of weight trace 14 as shown in Figure 2.
~he d.c. output signal from the scaling ampli~ier 12 - 5 - ;
7~7C~
is also applied to an agitation monitor 15 which is responsive ~ :
to that part o~ the d.c. output s:ignal produced by the agitation of the contents of t~e vessel 1 and which ~or molten steel and slag in the ~essel 1 has been found to be a frequency band within the range 0 a5 Hz to 5.0 Hz. ~he output signal from the agitation monitor 15 is passed to an agitation recorder 17 which produces a trace 18 as shown in ~igure indicative of the agitation o~ the ~olte~ contents o~ the vessel 1. ~ . :
In carrying out the steelmaking process the output of the scaling amplifier 12 is adjusted so that it reads zero as indicated at point 19 on trace 14, and oxygen is then injected into the molten char~e by lance 7. Fluxes are then :
introduced into the vessel 1, causing the recorded weight to i~crease towards a value indicated at poin~ 22~ The injection o~ the oxy~en causes carbon to be removed ~rom the .~-molten charge a~d leave the vessel 1 as either carbon monoxide or carbon dioxide which tends to reduce the recorded weight, while silicon and then manganese ~nd phosphorus are removed . 20 from the molten charge and appear in the slag, mainly as oxides~
which tend to increase the recorded weight. During this time ~ :
there may be periods when the recorded weight of the furnace contents tends to remain substantiall~ constant as indicated b~ i the portion of trace 14 between the points 20 and 21. ..
~ubsequently, a small amount of carbon is oxidised and iron .', ' ' ' '' ~
~`
q~
oxides build up in the slag so that the recorded weight again begins to increase towards a value indicated at the poin-t 22 on the trace 140 Finally, there is a secondary decarburiza-tion of the molten charge which brings down the carbon level to the finishing level and progressively reduces the recorded weight as indicated by the portion o~ the trace 14 between points 22 and 23.
During this period of secondar~ decarburization -the change of weight trace 14 tends -to fluctuate rapidly as indicated by the peaks 24 and troughs 25, and it has been fo~md that these fluctuations are indicative of the level of agitation of the liquid contents of the vessel 1 and are also indicative of the physical and/or chemical chan~es which are taking place at this time. ~herefore, by extracting that part of the output signal of the scaling amplifier 12 which produces the fluctuation and applying it to the recorder 17, a trace 18 as show~ in Figure 3 is obtained which is representative of the agitation in the liquid contents cf the vessel 1. For the fluctuations shown in the trace 14 it was found that the part of the output signal of the scaling amplifier 12 which was indicative of the level of agitation was a frequency band within the range Ool Hz to 1.0 Hz~
~ he trace 18 produced by the recorder 17 is used in the following manner to control the activity o~ the molten metal in the vessel 1. When oxygen is first in~ected into the molten charge, the tip of the lance 7 is positioned about .. ..
~04~ 70 100 inches above the surface of the molten charge~ lypically, with a mol-terl charge of 150 tons, o~ygen is inàected into the - ~ -molten charge at a substantially constant rate of 10~000 cubic ~eet per minute. After a period o~ one minute the tip of the lance 7 is gradually lowerecL to a height of 75 inches above the surface of the molten charge, and ~our minutes later the tip of the lance 7 is brought to a height o~ 50 inches above the surface o~ the molten char~eO ~inally, after a further two minutes the tip of the lance 7 is brought to a height o~
39 inches above the surface of the molten charge and remains at this height until the end of the steelmaking process.
If the tip of the lance 7 is lowered too soon the slag beco~es very viscous and i~ the lowering of the tip of the lance is delayed too lon~ the slag becomes foamy and may slop o~er the sides of the vessel 1.
~ he time at which the tip of the lance should ~e lowered to its ~inal powition above the surface o~ the molten charge can be ascertained from the trace 14 in ~igure 2 which at this time be~ins to fluctuate as indicated at point 27.
he time at which the fluctuatio~s co~mence can be more reaail~ ascertai~ed from the trace 18 which has a substantially linear rise at this time. ~here~ore, by preparing a calibration chart w~ich, for the vessel 1 with 150 ton molte~
charge and co~stant rate o~ oxygen injection as described above, consists of an idealized curve o~ substa~tially the same shape , '', . .
la~ o as trace 187 the point 28 on the trace 18 at which the lance 7 should be lowered to its final height can readil~ be ascertained. In practice the optimum position ~or the poi~t 28 has been found to be midway along the linear portion o~ the trace 180 When the secondary decarburization nears completion the fluctuations o~ the trace 14 diminish in amplitude as can be seen from the portion of the trace near to the point 23, and it is at this time that the injection of oxygen into the molten charge needs to be terminate~ by raising the lance 7.
The optimum time for te~minating the process can be more readily ascertai~ed ~rom the trace 18 which has a substantially linear fall at this time. In practi~e it has been found that the optimum time to termina~e the injection of o~ygen corresponds tc a point 29 midway along the linear portion of the trace 18~
~lthough the rate of oxygen i~jection was kepk substantially cons~ant in the process described above9 calibration charts can also be prepared to cover predetex~ined variations in the rate o~ oxygen injeGtion during the process, provided that the predetermined vaxiation in oxygen injection is repeated faithfully when the process is being controlled.
Moreover, although the oxygen was inaected by means of a lance 7 in the process described above, vessels employing bottom blowing o~ oxygen utilizing a valve 31 in the bottom of the vessel 1 are also suitable ~or caxrying out khe process~
_9_ .. . .
~o~
It is envisaged that t:he method and apparatus o~ ~
the invention will fi~d use in man~ other industrial pxocesses .: . :
in which the treatment of a medium in a vessel produces agitation of the medium which is related to the physical ,~
and/or chemical changes taking place in the medium.
In particular it is thought that the method a~d apparatus o~
the in~ention will ~ind use in brewing and winemaking processes wherein the additio~ of ~east to a liquid medium :-results in fermentation accompanied by agitation of the liquid which can be monitored, recorded and used to control the progress o~ the process in a manner similar to that described aboveO
~ ': ' !
-10~
Claims (26)
1. Apparatus for controlling the treatment of a medium in a vessel comprising means for monitoring the weight of the contents of the vessel and producing an electrical signal indicative of the apparent variations in weight of the contents of the vessel, means for extracting from the electrical signal that part of the signal produced by agitation of the medium in the vessel, means for recording said part of the signal, and calibration means correlating the characteristics of the medium, time, and the amount of agitation in the medium whereby the progress of the treatment can be controlled.
2. Apparatus as claimed in Claim 1, wherein the weight of the contents of the vessel is monitored by a plurality of force measuring transducers.
3. Apparatus as claimed in Claim 2, wherein the force measuring transducers are incorporated in pedestals supporting the vessel.
4. Apparatus as claimed in Claim 2 or Claim 3, wherein each force measuring transducer comprises a steel billet to which is bonded a foil strain gauge sensitive to tensile or compressive load, and the foil strain gauges are connected in an electrical bridge circuit arranged to produce the electrical signal indicative of the apparent variations in weight of the contents of the vessel.
5. Apparatus as claimed in Claim 1, wherein the means for extracting from the electrical signal that part of the signal produced by agitation of the medium in the vessel is responsive to a frequency band within the range 0.05 Hz to 5.0 Hz.
6. Apparatus as claimed in Claim 1, wherein the means for extracting from the electrical signal that part of the signal produced by agitation of the medium in the vessel includes a monitor responsive to the said part of the signal.
7. Apparatus as claimed in Claim 6, wherein the monitor is responsive to a frequency band within the range 0.1 Hz to 1.0 Hz.
8. Apparatus as claimed in Claim 1, Claim 2 or Claim 5, wherein the recording means is arranged to produce a trace indicative of said part of the signal.
9. Apparatus as claimed in Claim 1, Claim 2 or Claim 5, wherein the calibration means comprises an idealized curve prepared from data obtained from previous treatments of the medium in the vessel.
10. Apparatus as claimed in Claim 1, wherein the medium is a molten charge being treated in a steelmaking process involving the injection of oxygen, and the vessel is a refractory vessel.
11. Apparatus as claimed in Claim 10, wherein the oxygen is injected by means of a lance disposed above the molten charge.
12. Apparatus as claimed in Claim 10, wherein the oxygen is injected through valve means in the bottom of the vessel.
13. A method of controlling the treatment of a medium in a vessel, comprising the steps of monitoring the weight of the contents of the vessel and producing an electrical signal indicative of the apparent variations in weight of the contents of the vessel, extracting from the electrical signal that part of the signal produced by agitation of the medium in the vessel, recording said part of the signal, and thereafter controlling the progress of the treatment of the medium by comparing the record with a previously established relationship correlating characteristics of the medium, time, and the amount of agitation in the medium.
14. A method as claimed in Claim 13 in which the medium is a molten charge that is being treated in a steel making process involving the injec-tion of oxygen, wherein the part of the signal produced by agitation of the medium in the vessel is a frequency band within the range 0.05 Hz to 5.0 Hz.
15. A method as claimed in Claim 13 in which the medium is a molten charge that is being treated in a steel making process involving the injec-tion of oxygen, wherein the part of the signal produced by agitation of the medium in the vessel is a frequency band within the range 0.1 Hz to 1.0 Hz.
16. A method as claimed in Claim 13, wherein the weight of the contents of the vessel is monitored by a plurality of force measuring transducers.
17. A method as claimed in Claim 16, wherein the force measuring transducers are incorporated in pedestals supporting the vessel.
18. A method as claimed in Claim 16 or Claim 17, wherein each force measuring transducer comprises a steel billet to which is bonded a foil strain gauge sensitive to tensile or compressive load, and the foil strain gauges are connected in an electrical bridge circuit arranged to produce the electrical signal indicative of the apparent variations in weight of the contents of the vessel.
19. A method as claimed in claim 13, Claim 14 or Claim 16, wherein the part of the electrical signal produced by agitation of the medium in the vessel is extracted by a monitor responsive to that part of the signal.
20. A method as claimed in Claim 13, Claim 14 or Claim 16, wherein the part of the signal produced by agitation of the medium in the vessel is recorded by recording means arranged to produce a trace of said part of the signal.
21. A method as claimed in Claim 13, Claim 14 or Claim 16, wherein the previously established relationship comprises an idealized curve prepared from data obtained from previous treatments of the medium in the vessel.
22. A method as claimed in Claim 13, wherein the medium is a molten charge being treated in a steelmaking process involving the injection of oxygen.
23. A method as claimed in Claim 22, wherein the oxygen is injected by means of a lance disposed above the molten charge.
24. The method as claimed in Claim 22, wherein the oxygen is injected through valve means in the bottom of the vessel.
25. A method as claimed in Claim 23 or Claim 24, wherein the oxygen is injected at a substantially constant rate.
26. A method as claimed in Claim 23 or Claim 24, wherein the oxygen is injected at a rate which varies in a predetermined manner.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB5756773A GB1486423A (en) | 1973-12-12 | 1973-12-12 | Method and apparatus for process control |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1041770A true CA1041770A (en) | 1978-11-07 |
Family
ID=10479500
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA215,754A Expired CA1041770A (en) | 1973-12-12 | 1974-12-11 | Kinetic energy monitor |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS5092211A (en) |
| AR (1) | AR223128A1 (en) |
| BR (1) | BR7410290A (en) |
| CA (1) | CA1041770A (en) |
| DE (1) | DE2458532A1 (en) |
| ES (1) | ES432805A1 (en) |
| FR (1) | FR2254783B3 (en) |
| GB (1) | GB1486423A (en) |
| IT (1) | IT1027053B (en) |
| NL (1) | NL7415400A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT347984B (en) * | 1975-08-14 | 1979-01-25 | Voest Ag | SLIDING JOINT BEARINGS, IN PARTICULAR FOR TILTING CONVERTER |
| AT347988B (en) * | 1976-02-03 | 1979-01-25 | Voest Ag | TILTABLE, METALLURGICAL VESSEL, IN PARTICULAR STEELWORKS CONVERTER |
| US4191885A (en) * | 1978-12-12 | 1980-03-04 | Hylsa, S.A. | Method for determining weight of molten metal in situ |
| US6808550B2 (en) | 2002-02-15 | 2004-10-26 | Nucor Corporation | Model-based system for determining process parameters for the ladle refinement of steel |
-
1973
- 1973-12-12 GB GB5756773A patent/GB1486423A/en not_active Expired
-
1974
- 1974-11-26 NL NL7415400A patent/NL7415400A/en not_active Application Discontinuation
- 1974-12-04 JP JP13942574A patent/JPS5092211A/ja active Pending
- 1974-12-09 BR BR1029074A patent/BR7410290A/en unknown
- 1974-12-11 FR FR7440855A patent/FR2254783B3/fr not_active Expired
- 1974-12-11 DE DE19742458532 patent/DE2458532A1/en not_active Withdrawn
- 1974-12-11 ES ES432805A patent/ES432805A1/en not_active Expired
- 1974-12-11 IT IT7060474A patent/IT1027053B/en active
- 1974-12-11 CA CA215,754A patent/CA1041770A/en not_active Expired
- 1974-12-12 AR AR25688574A patent/AR223128A1/en active
Also Published As
| Publication number | Publication date |
|---|---|
| ES432805A1 (en) | 1976-11-01 |
| BR7410290A (en) | 1976-06-29 |
| IT1027053B (en) | 1978-11-20 |
| JPS5092211A (en) | 1975-07-23 |
| AR223128A1 (en) | 1981-07-31 |
| DE2458532A1 (en) | 1975-06-19 |
| FR2254783A1 (en) | 1975-07-11 |
| GB1486423A (en) | 1977-09-21 |
| NL7415400A (en) | 1975-06-16 |
| FR2254783B3 (en) | 1977-09-16 |
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