CA1039924A - Endless belt continuous casting machine method and apparatus - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Method and apparatus for determining the operating conditions in a continuous metal casting machine of the type having a revolving endless casting belt with a casting sur-face adapted to confine the molten metal and which is covered with a belt coating to insulate and protect the belt from the molten metal and a reverse surface adapted to be cooled by high velocity liquid coolant, such as water. The method and apparatus can be used to determine molten metal pool level and also to determine the belt coating condition and include one or more series of at least two heat sensing detectors, mounted with their tips in bearing relation against the mov-ing reverse, cooled surface of the casing belt in positions to be surrounded by the high velocity liquid coolant flow.

Description

`~ The heat sensing aetectors are each encased in a , . . .
compact streamlined casing so as to cause minimum distur- ..
bance to the high velocity flow of liquid coolant rushing by on both sides, and they are insulated to prevent the surroun-,~ ding coolant from completely masking the temperature sensing action occurring at the tips of detectors where they bear against the moving reverse surface of the belt. ` .

, DESCRIPTION

10 l' The present invention relates to method and . ,. !
apparatus for determining the operating conditions in a continuous metal casting machine of the type having an end- , I
less casting belt for confining l:he molten metal. The method, ll and apparatus embodying this invention can be used for deter~ l 1' mining the molten metal pool level and can be used to deter- I i mine the condition of the belt coating which protects and I .

I¦ insulates the front surface of the belt from the molten metal! i !l in contact therewith. ~ , !, ¦
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!' i It is impor-tant that molten metal be introduced into the input region of the continuous casting machine at a rate which is effectively synchronized with the casting rate of the machine as determined by the belt travel so as to maintain the pool of molten metal in the input of the machine at a desired level. When the infeed rate exceeds the casting rate, the pool level will creep up until suddenly the molten metal spills out and overflows out of the input. Such an overflow necessitates a-difficult and expensive clean up and is hazardous to personnel and to the casting installation.
When the infeed rate is less than the casting rate, the pool level will creep down into the machine allowing the molten I
metal being introduced to cascade down too far before reaching i ~ , the pool causing splashing and turbulence within the machine.
l Such splashing and turbulence causes non-uniformity and segregations in the cast product. Also, the low pool level leaves too large a space above the pool containing gases or dross which can become trapped within or adjacent to the l~molten metal being introduced, thus causing impurities, 20 ¦Ihollows or voids in the cast product. I -` When the infeed rate is precisely matched to the 'casting rate, these casting belt machines can be run contin- ¦
uously for long periods to successfully and efficiently cast j,large tonnages of strip or slab product.
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l, In order to achieve optimal casting conditions, it i ,is also important to control the condition of the insulative ¦
and protective coating on the front faces of the endless beltl adjacent to the molten metal. In particular, the effectiveness -3- `

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` . ` ` ' , " `. ' ,` of this coatiny in performing its function is dependant upon its thickness, its density, its uniformity of distribution, and its insulative quality or its resistance to heat transfer.
The method and apparatus of the present invention I may be used w1th advantage to determlne the pool level of ~ ¦
¦I molten metal being cast by a continuous belt metal casting machine. Additionally, the method and apparatus may be used with advantage to monitor the condition of the belt coating used in such machines on the front surface o~ the endless ~l belt where it is directly in contact with the molten metal ¦j being cast.
In actual practice it is extremely difficult to l meter the infeed rate of molten metal and also extremely difficult to determine the level of the molten pool. In most ¦! cases the molten pool is h.idden from sight by the equipment ¦ associated with the input region of the machine. Even if a small observation opening is attempted to be provided from ¦ one side~the surrounding insulation material and the slag anl I dross floating on the molten pool prevent accurate determina' I tions to be made of the actual level of the molten pool.
!I The continuous movement of the casting belt and th~
il high velocity liquid coolant rushing along the reverse sur- ~ ;
face of the belt plus the heat are further impediments to ! `
¦¦ determination of pool level. ISihce the molien metal is at i its highest temperature as it is being introduced into the li pool, the amount of heat flux is greatest and so an intenslvel il and continuous cooling o~ the reverse sur~ace of the belt is ~ ;
~' absolutely essential in this lnput and pool region. ¦ -, . I ,~, ., :, . ,, j 1`
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A variety of methods have previously been used in attempts to determine the pool level of molten metal being ' cast in such continuous casting machines. Among these methods ~, is the use of the operator's eye and electronic and mechanical sensors. Thermocouples, mounted in the slde metal retaining ` dam, have also been utilized. However, ail these electronic i and mechanical methods which have been tried are generally very expensive to implemsnt. In addition, all of ~hese prior -~ ;
, art techniques including visual observation have experiencedl more or less interference and non-responsiveness or lapses ij , functioning due to heat, fume9 fxom the molten metal and casting process, impurities or slag and dross build up as 1ll well as effects o the high velocity coolant flow, and other I factors.
Il More recently in attempts to overcome the inter-ference, non-responsiveness and failures of the prior art ¦ methods, the sensing of the pool level has been carried out I
I by the use of beams of gamma rays rom a radioactive cobalt , ~ource which are sent through the input region of the machine ¦ wh~re the pool of molten metal is intended to be located. ¦ ~ "

This use of gamma ray pool level sensing techniques is expen . _ il sive, complex and dangerous. In actual practice in fflany case il the gamma ray technique has not worked out much better than 1¦ some of the earlier methods.
With respect to the indication of the condition of , `
the belt coating, several prior art methods have been employed. The most common method has been based on the ~i I .
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~0399Z4 casting machine operator's subjective judgment of the a~ear-;
llance of coating and belt together with the appearance of the !, cast product as it exits from the machine. T~ coating con- i 'dition has been indirectly determined by taking temperature Ireadings on the surface of the solid cast as it emerges from i the casting machine. A third method utilized occasional , tests o~ the coating thickness by a magnetic or other type gauge.
~1 All of these methods yield only a qualitative lindication of the belt coa~ing heat transfer resistance con-dition. Additionally, these methods may be subject to error ~due to interference caused by other factors such as rate of travel and temperature of the ~elt.
~1 In summar~, the prior art methods and apparatus 15 lll for determining the pool level of molten metal and the belt i ~coating condition in such t~pes of continuous metal casting machines have had serious draw~acks. I
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-of--the present invention , In the preferred embodimen ~to be described in Idetail hereinbelow, the method and apparatus of t~e present invention determines the molten metal pool leYel in a con- ~
tinuous casting machine of the type having an endless castîng !
belt. This method and apparatus can be used for determining the condition of the insulative and protective coating cover-~

25 il ing the casting belts. The method and apparatus employ one,or more series of at least two heat sensing detectors mounted ,with their tips bearing against the moving reverse~ water Icooled surface of the endless casting ~elt in positions to ~e, ¦~surrounded by the coolant. The high ~elocity flaw of liquid ,coolant is directed against and travels along t~is reverse belt surface.

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The first detector series is mounted to bear ', against the reverse, cooled surface of one of the endless casting belts and e~tends longitudinally in tne direction of belt travel. This detector series is positioned to span the I desired molten metal pool level in the casting machine. The temperature of the casting belt increases when it is in con-tact with the molten metal being cast. I have found that b~
l~taking the steps described further below, this increased ¦Itemperature becomes distinguishable at t~e belt-liquid I

,,coolant interface, in spite of the,presence of the high , velocity coolant flow. Therefore, this first series of de- `, tectors determines the molten metal pool level b~ detecting such temperature increases or subsequent decreases at the l'various lonyitudinal detector locations. It is n~t necessary~
¦Ithat temperature be accurately measured at each such detector bearing point. Each detector indicates when the temperature ¦increases or decreases significalntl~ at its location,to j ¦thereby indicate when the pool level changes above or below ¦
Ithat location. ¦
j A series of detectors extending laterall~ across ¦
the belt can be employed to serve the relative belt temper- I
l¦atures at the locations of each individual detector. In a l! twin-belt machine a series of detectors can be employed with j ¦jboth the upper and lower belts.
25 1l The best direct indication of coating condition is !, the temperature of the casting belt when it is in contact ~with the molten metal being cast. It is impracticalr however~
to measure belt temperature at the belt-coating interface. ¦
IlHowever, b~v taking the st,eps described further below, the ~ temperature of the belt at the belt-liquid coolant interface !
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can be directly, quantitatively related to various coating properties, particularly coating heat transfer resistance, which reveal coating condition. Therefore, by utilizing a suitable means of data interpretation, for example a tempera ture-heat transfer resistance table, the temperature of the ,, casting belt at points spaced across the belt-liquid coolant~
interface measured by the second detector series can be re-lated to the coating property being mon tored.
Both the first and second series of detectors are 1, `
, mounted in a spaced fashion laterally across the belt so thatj minimal interference with the high velocity continuous flow of liquid coolant results.
Each series of detectors may be utilized in conjunc _ Il tion with any suitable equipment for monitoring the tempera-j tures and temperature variation which they sense. ¦
Alternatively, the first and second detector series may be used in conjunction with automatic equipment which controls the rate of feed of molten metal into the casting machine to maintain the desired pool level or which automa- ¦
20 ¦I tically stops the casting process when the belt coating has deteriorated or become non-uniform to a degree making it , ineffective in insulating and protecting the casting belt or , adversely affecting the uniformity of the cast product.
The detectors in each series include a voltage i, generatlng element, such as a thermistor or contact thermo-couple, embedded in a matrix of waterproof insulating material which in turn is mounted with a bearing tip of metal of good heat Fonductivity. This bearing tip con-tac s .he voltage ?l -8 ,: ' , , ` ~: ' .

' 1039924 , generating element on its interior side and contacts the reverse belt surface on its exterior side.
The detector is fitted into a streamlined jacket , which presents little impedance to the high velocity flow o~
liquid coolant directed against it. The detector assembly is 1~' associated with a spring-loaded member which is appropriately mounted on the casting machine frame to correctly position , I the detector in the desired location to form a series. The i spring urges the bearing tip of the detector assembly into j contact with the moving casting belt.
The detector assembly is also constructed so that ~
the jacket shields the generating element from lateral thermall !~ e~fects due to the continuous rushing flow of coolant. The 1,1 high conductivity bearing tip contacting the reverse belt I ¦
surface transmits thermal energy rom the belt sur~ace. ¦

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I~ _g_ ~.039924 BRIEF DESCRIPTIO~ OF THE DRA~7INGS
, FIGURE 1 is a side elevational sectional vie~ of a , , continuous metal casting machine equipped ~ith a series of ~ heat sensing detectors which determine molten metal pool , level, and/or belt coating condition.
FIGURE 2 is an enlargement o a portion of Figure 1.
FIGURE 3 is an enlarged cross-sectional view of this ~ .
apparatus taken through plane 3-3 in Figure 2 looking up, ~ which illustrates the locations of the individual heat sen-' sing detectors of both detector series.
FIGURE 4 is an enlarged elevational sectional view o~Il two heat sensing detectors mounted in spring loaded tubes on , ¦, mounting arms taken through the broken plane 4-4 in Figure 3.
FIGURE 5 is an enlarged cross-sectional view oE one ~.l heat sensing detector taXen through plane 5-5 of Figure 4 looking upward showing the streamlined shape of the upper l detector jacket body.
- 11 . FIGURE 6 is an enlarged cross-sectional view of the ¦I same heat sensing detector taken through plane 6-6 of Figure j 20 1~ 4 looking upward illustrating the circular shape oE the lowe~ ~
~ detector jacket body mounted in a spring loaded tubular !, holder. I
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, Corresponding reference numerals indicate corres-,I ponding structural elements and corresponding characteristic ,~ features in each of the respective drawings.--lo- - ! -,~

li 10399Z4 l~
i An illustrative example of a continuous metal ~
casting machine equipped with an embodiment of the presen-t j invention is shown in Figure 1. In this casting machïne, molten metal 12 is supplied from a pouring box 14 and flows , I down through a pouring spout 16 into a tundish 18. The rate ¦-¦lof flow is controlled by a tapered stopper 20 on a control rod 22. The molten metal is fed through a no7zle 24 into the input region 25 leading into a casting region C formed I between the upper and lower endless flexible casting belts l 26 and 28. These belts are fabricated from steel, or other alloys, which provide toughness and resistance to abrasion ~land physical damage as well as resistance to the temperature ¦~shocks and heat differential stresses undergone during cast-l'ing. As shown in Figures 2 and 4, each belt has a protective ¦ and insulative coating or dressing 29 on its casting surface Il (called the "front" surface).
¦~ The casting belts 26 and 28 are supported and driven by upper and lower carriages, generally indicated at l30 and 32, mounted on a machine frame (not shown). Each Icarriage includes two main rolls 34, 38 and 36, 40 to support¦ -Idrive and steer the casting belts, and these belts are gulded¦
I by multiple, finned back-up rollers 41 (Fig. 4) in the - , desired relationship along the casting region C. Thesè
, back-up rollers 41 may be as shown and described in U.S.
1! Patent No. 3,167,830.
i A flexible, endless dam 44 defines each side of the casting region for confinin~ the molten metal. The ~i, two side dams 44 are guided toward the input by guide me~bers 46, for example, as shown in said Patent No. 3,167,830.

, . --11-- ~, ~039924 i I During the casting operation, the two casting !

belts 26 and 28 are driven at the same linear speed by a -i . i driving mechanism 47, for example, as described in said , patent.
, Tremendous heat flux is withdrawn through the ' upper and lower casting belt by a high velocity layer 48 of liquid coolant, shown in Figùres 2 and 4, tra~eling I~along the reverse belt surfaces 50 and 52, respectively. The ¦lliquid coolant, preferably water containing a corrosion in- , 0 Illhibitant, is maintained in a layer 48 in a manner as shown in I said patent. , ! The casting 58 from the casting machine may be conveyed and guided by feed rollexs 60, two of which are show I'in Figure 1. `
~, To determine the position o~ the pool P of molten~
metal in the input region 25 of the machine, there is a series 62 (Figs. 1 and 2) of five heat sensing detectors, 62 ! 62b, 62c, 62d, and 62e which engage against the cooled l I ¦ reverse surfacè 52 of the lower belt 28 near this input region ¦AS many of these detectors as is desirable may be used in ~

locating the pool level. The numiber of detectors in the series 62 should not be so great as to slgnificantly obstruct !
¦'~the liquid coolant 48 travelling along the reverse surface 52 As shown in Fig. 4, these heat sensing detectors J
l'62a-62e are positioned between the back-up rollers 41 to avoid ¦, interference with these rollers. Each dètector is moùnted I
¦ on an individual support arm 64a, 64b, 64c, 64d, and 64e, whi 'i is mounted on and laterally extends from the lower carriage Il 32. The first detector 62a, or the first and second l~ detectors 62a and 62b (or more of them) may be mounted in the !i grooves 63 of the lower input roll 36 bet~een its ridges 65 Ii . I
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to be beneath the upstream limit of the pool P. A mountingfinger 69 (Fig. 3) extends upstream from the arm 64c into the'l respective grooves 63 for supporting the respective detectorsl l in the groove or grooves. However, any suita~le means for ¦
''mounting the detectors in a fixed location in bearing rela- I
tion with the reverse cooled belt surface 52 may be employed.l ¦
Instead o engaging the lower belt, it is also ¦
possible to determine the location of the pool P by mounting ¦
jithe detector series 62 to bear against the reverse, cooled llsurface 50 of the upper casting belt 26, near the input ¦Iregion 25.
! In the case of a twin-belt casting machine, as ¦lshown~ in certain instances it may ~e advantageous to utilizej ¦¦a series of detectors 62 and another series 162 engaging ¦¦ the reverse surfaces of both casting belts 26 and 28 for !¦ determining the position of the pool P. It may be advanta-¦geous to utilize a series of detectors 70 and another series !
¦i170 engaging the reverse surfaces of both belts 26 and 28 llfor monitoring the condition of the belt coating 29 or

2~ coatings.

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` 1039924 " If desired, all four series o~ detectors 62, 162, 70 and 170 may be used in a twin-belt casting l machine. Alternatively, any combination of one, two, thre~
,ior four of the series of detectors 62, 162, 70 and 170 I,ca~ be used. It is noted that the detector series 162 and ~ 170 for the upper belt are located further downstream than i those for the lower belt because the downward inclination of the casting region C causes the molten surface meniscus lof khe pool P to be positioned at an oblique relationship Ito both casting belts 26 and 28, as seen in FIGS. 1 and 2.
The pool level detectok series, 62a-62e, is ¦ positioned to span the desired pool position, that is, I
~the series 62 extends longitudinally (i.e. upstream-downstre~m) I in the direction of belt travel. The leading detector 62a ¦ ¦
¦!is positioned at a point above the desired pool position;
l~and the trailing detector 62e is positioned at a point ¦
I below the desired pool position. The remaining detectors ¦62b, 62c and 62d are positioned intermediate the leading and trailing detectors.

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Each heat sensing detector is responsive to ~localized chanc,es in belt temperature on the reverse, cooled `
belt surface 52 adjacent to its own tip. As noted, when a localized region of the casting belt is in contact with the 1i molten metal being cast, the temperature of the reverse surface of the casting belt increases in that region due to the increased amount of heat transfer occuring In , view of the intensive cooling action of the rushing coolant -;48, the amount of temperature increase at the reverse surface j 52 is not very greàt, but it can be effectively sensed by following the steps described herein. Thus, the detector series 62 senses an upstream or downstream shifting in position of the pool P by sensing a localiz~d increase or de-l~crease in belt temperature at the respective longitudinal llocations of the detectors 62a, 6;'b, 62c, 62d and 62~ or of I
the detectors 162a, 162b, 162c, 162d and 1~2e ~or of all of ¦
¦~them) in the direction of belt travel. '~
¦i Each of t~ese detectors in the series 62 or 162 ¦~or both) is connected to a pool level data output monitor 66 ¦(Fig. 1), wh1ch may be any suitable monitor means for indi- ¦

cating the temperature change registered by individual lldetectors in this pool level series 62 and 162. For example, ¦~monitor 66 may include a sequence of electrical relays control,-¦,ling colored lights, each relay being`responsive to a corres-¦
¦'ponding detector 62a-62e or 162a-162e. Each relay causes the¦

¦llight to become energized when its corresponding detector l,senses a significant temperature increase. The casting ap- ~
¦Iparatus operator can then manually adjust control means 71 ¦ ;
~for regulating the flow of molten metal into the casting machine until the desired pool level ls being maintained.
i~Any other monitor means, such as a sequence of recording ¦ pens or audible signals, may similarly be employed. The con-l 1'' 1 .
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~ 1039924 trol means 71 may include a manually adjustable or motor-driven ,feed screw for raising or lo~.~ering the stopper 20.
Alternatively, the monitor and control 66 may include automatic control equipment to regulate the feed of Imolten metal. As shown in Figure 1, the controller 66 is connected by circuits 67 to the control means 71 which moves ~the stopper 20 to control metal flow. The motor-driven control 71 may include servo-mechanism connected to the equip-'ment 66 for fully automatic flow regulation. -l As shown in Figure 3, the pool position detector series 62a-62e is staggered across the belt width to avoid I~any significant obstruction in the rushing flow F o coolant.
1, In the above methods of controlling the position ¦'of the pool P, the rate of molten metal in-feed is controlled ;~ither manually or automatically t:o match the metal in-feed ¦ ¦
Ito thecasting rate as determined by the rate of travel of ~ ¦
Ithe belts 26 and 28. ~ ¦
i Another method which can be used in some cases ¦to control the pool position is to stabilize the rate of ¦in-feed of the molten metal 12 at a desired value and then ¦
¦gradually to vary the speed of the machine by slight amounts ~ I
~¦to match the actual input of metal. As shown in Fig. 1, ~ I
the control equipment 66 is connected by electrical circuit 1 ¦

I~means 73 to the drive mechanism 47, which turns the rolls 38 ¦ and 40 simultaneously and synchronously.` Also, the - ¦
iicontrol equipment 66 is connected by circuit means 75 to !
the drive mechanism 76 for the out-feed conveyor rolls 60.
~IThus, the speed of the casting machine and ¦,out-feed rolls 60 can be automatically matched to i~the in-feed of molten metal to control the ~'` - ' I ~ . .
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~l position of the pool P.
In most cases, it is preferable to regulate in-feed while the casting machine runs at constant speed, `

~because constant speed facilitates operation of the rolling and handling equipment for product 58, which is often in line ~with the casting machine.
To monitor the condition of the belt coating 29, a second series 70 or 170 (Figs. 1, 2) of five heat sensing Ildetectors 62e, 70a, 70b, 70c, and 70d (Fig. 3) may be instal-,lled near one or both belts. These are preferably located, ,jas shown in Fig. 3, at uniformly spaced points across the ¦wi~th of the belt. As many o~ these detectors in series 70 or 170 may be used as desired to provide a plurality of data llsensing locations. Again, the number of detectors in series Il 70 or 170 should not be so large ~s would unduly interfere ¦liwith the coolant flow F.
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' If desired, as shown in Fig. 3 t the trailing ¦ -¦Idetector 62e in the pool level sènsing series 62 forms one ¦of the detectors in the coating condition monitor series 70.
¦In the series 70 (and 170), all detectors may be mounted on la single support arm 64e or 164e.
¦l Any other suitable mounting means may be ,~employed which fixes ths coating condition detector series at¦

¦~a given location in bearing relation with the reverse, cooled "' ¦~surface of the casting belt.
¦~ The belt coating condition detector series 70 ¦ or 170 is positioned in line with the trailing pool level detector 62e or 162e because at this longitudinal location jimolten metal should always be in positive contact with the 1 -!,, full width of the cas-ting belt. An indication oE coating ,condition is the temperature of the reverse belt surface ' -16-, l. l when the coating on the front ~elt su~ace is in contact with the molten metal being cast. Therefore, the coating condi-~jtion detector series is positioned at laterally spaced positions across the belt near the pool P.
As shown in Fig. 3, the coating conditions detector series 62e, 70a, 70b, 70c, and 70d, is connected to a coating condition monitor 72, including temperature recording indicators for the respective temperatures sensed. The i ~ -' operator may relate the temperatures to various belt coating ¦ ~ -' properties using data interpretation ta~les based upon past I operating experience for the type of coating 29 being used.
¦IIt is to be understood that the other detector series 170, i ¦ when used, is also connected to the monitor 72.
ll The monitor 72 may be connnected to the drive Imechanisms 47 and 76 to automatically stop the machine when ¦
the coating 29 has deteriorated or become undly non-uniEorm j for pérforming its insulative and protective functions for I
casting quality product. I I -i¦ The embodiment of the heat sensing detector used , -~
- 20 I in both the pool level and coating condition detector series 62 and 70 is illustrated in detail in Figs. 4, 5 and 6.
~Figure 4 illustrates detectors 62c and 62d in elevational ¦i cross-section. Each detector includes a jacket 80 of smooth ~`2 1! material of low heat conductivity such as polytetrafluoro-¦~ ethyiene, e.g. "Teflon'l which is streamlined to the flow F
¦I near its tip end, near the reverse belt surface 52. This I streamlined cross-section 82 is shown in Fig. 5, defined ¦ by a parabolic leading face 84 and a V-shaped cusp trailing I~ face 86. The coolant flow F is indicated by arrows.

l~ Slippery plastic 80 reduces friction on belts. At this mountt I~ '. ;' ' .
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ing end, the insulating jacket 80 has a circular cross-section 88 (Fig. 6). The circular portion 88 of jacket 80 slip fits into a tubular bracket 90 mounted on the respective , supporting arm 64c, 64d, etc. A spring 92 urges the I telescoped jacket 80 toward the reverse belt surface 52.
Each insulating jacket 80 has an axial bore 94, , with a thermally highly conductive metal sleeve 100, for example, of copper, press fitted into the bore end. This l conductive sleeve 100, mounted in the very end of jac~et 80 I is formed with a closed end 102 which directly contacts and slides against the moving belt surface 52. A heat-responsive ~voltage generating element 104, such as a thermistor or con~
ltact thermocouple, having lead wires 106, is inserted into ¦
~ sleeve 100 in contact with its end 102 and is potted in an Ilelectrically insulative, waterproof material 108, such as epoxy pla~tic. The lead wires 106 are connected to the ,appropriatè monitor and control means 66 and/or 72. Heat lis conducted from the belt, through the closed end 102 of the ¦cap and into the sensor element 104. I
20 ¦ This detector arrangement insulates the heat Iresponsive element 104 from lateral cooling effects caused by the coolant flow. However, axial heat flux travelling from the molten metal, conducted through the belt and belt-!`` engaging cap 100 are readily detected. -25 ~~ - The invention may also be employed to advantage ¦~ with the casting belt of a wheel-and-belt casting machine ¦ for monitoring the operating condition of the machine such ¦ ;
¦~ as the molten pool level at the input and the condition of ij the belt coating. Such a wheel-and-belt type casting machine ~' is shown in U.S. Patent No. 3,429,363.
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Although a specific embodiment of the invention has been disclosed herein in detail, it is to be understood that this is for purposes of illustration.
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Claims (28)

The embodiments of the invention in which an exclusive property or privelege is claimed are defined as follows:

1. The method of determining the operating conditions of a continuous metal casting machine of the type having at least one endless flexible, revolving casting belt with a casting surface which engages the molten metal to be cast and a reverse surface, cooled by liquid coolant, said casting surface being covered with a coating of insulative material, said method characterized by the steps of: positioning a series of heat sensing detectors in contact with the moving, reverse, liquid-cooled surface of the casting belt at predetermined positions;
urging said heat sensing detectors against the moving, reverse surface of the casting belt to obtain heat transfer therefrom;
arranging said series of heat sensing detectors to present minimal interference to the flow of liquid coolant on the reverse belt surface; insulating said heat sensing detectors from the flow of liquid coolant, and monitoring the responses of said series of heat sensing detectors for determining the operating conditions of the casting machine as molten metal is being cast therein.

2. The method of determining the operating conditions of a continuous metal casting machine as claimed in Claim 1, characterized by streamlining said heat sensing detectors to minimize interference with the flow of liquid coolant on the reverse belt surface.

3. The method of determining the operating conditions of a continuous metal casting machine as claimed in Claim 1, char-acterized by positioning a series of heat sensing detectors at predetermined positions spaced across the width of the casting belt to monitor the belt coating conditions across the belt width as molten metal is being cast.

4. The method as claimed in any one or more of Claims 1, 2 or 3, wherein there is a grooved roll associated with the casting belt near the input region, characterized by pos-itioning at least one of said heat sensing detectors in a groove of said roll in contact with the moving, reverse surface of the casting belt.

5. The method of determining the operating conditions of a continuous metal casting machine as claimed in Claim 1, wherein there is a molten metal pool in the input region of the machine further characterized by positioning a series of at least two heat sensing detectors in contact with the moving reverse, cooled surface of the casting belt in upstream-down-stream spaced relation to span the desired predetermined operating range in pool position; and monitoring the responses of said detectors to changes in the temperature of the moving reverse cooled surface of the belt at the respective positions of said detectors to determine the position of the molten metal pool.

6. The method as claimed in Claim 5, characterized by the step of maintaining the rate of infeed of the molten metal matched to the speed of the machine to keep the pool position within a desired predetermined range in operation.

7. The method as claimed in Claim 5 or 6, characterized by holding the speed of belt travel constant; and varying the rate of infeed of the molten metal to match the belt travel, thereby to keep the pool position within a desired predetermined range in operation.

8. The method as claimed in Claim 5, characterized by stabilizing the rate of infeed of the molten metal into said input region; and varying the speed of belt travel to match the actual infeed of molten metal, thereby to keep the pool position within said desired predetermined range in operation.

9. The method as claimed in any one or more of Claims 5, 6 or 8, characterized by laterally staggering the positions of said detectors to present minimal interference to the flow of liquid coolant along the reverse surface of the casting belt.

10. The method as claimed in Claim 5, characterized in that a first series of heat sensing detectors is located at positions spaced across the width of the belt in contact with the moving reverse belt surface and a second series of heat sensing detectors is distributed in positions relatively spaced upstream and downstream along the casting belt in contact with the moving reverse belt surface to span the desired range in operating positions of the molten metal pool.

11. The method as claimed in Claim 10, characterized in that the first series of heat sensing detectors is positioned downstream from the molten metal pool for sensing the belt temperatures soon after molten metal has come into contact with the front surface of the belt as the molten metal is being cast for determining the condition of the insulative belt coating after molten metal has come into contact with the belt coating.

12. The method as claimed in any one or more of Claims 5, 6 or 8, wherein the machine is of the twin belt type having an upper and lower belt, characterized in that said heat sensing detectors are positioned beneath the lower belt in contact with the moving, reverse, liquid-cooled surface of the lower belt in respective positions to span the desired location of the upstream edge of the molten metal pool.

13. The method as claimed in any one or more of Claims 5, 6 or 8 wherein the machine is of the twin belt type having an upper and a lower belt, characterized in that said heat sensing detectors are positioned in contact with the moving, reverse, liquid-cooled surface of the upper belt in respective positions to span the desired location of the edge of the molten surface mensicus in contact with the upper belt.

14. Apparatus for determining the operating conditions in a continuous metal casting machine of the type having at least one endless flexible revolving casting belt having a casting surface which engages the molten metal to be cast in a casting region and a reverse surface cooled by liquid coolant, said casting surface being covered with a coating of insulative material, said apparatus being characterized by a series of at least two heat sensing detectors located at spaced positions near said casting region; support means holding said detectors in contact with the moving reverse, cooled surface of said casting belt; said detectors being arranged to present minimal inter-ference to the liquid coolant on the reverse belt surface;
thermal insulation material associated with said heat sensing detectors for insulating them from the liquid coolant and monitor means connected to said heat sensing detectors to monitor the responses of said detectors to changes in the temperature of the moving reverse surface of the belt at the respective positions thereof to determine the operating conditions.

15. Apparatus for determining the operating conditions in a continuous metal casting machine as claimed in Claim 14, characterized in that said heat sensing detectors each include a tip of material of high thermal conductivity; and said support means include spring means urging the tips of saidheat sensing detectors firmly against the moving, reverse, liquid-cooled surface of the belt.

16. Apparatus for determining the operating conditions in a continuous metal casting machine as claimed in Claim 14, or 15, characterized in that said thermal insulation material is formed as a jacket surrounding said tip; and said jacket is streamlined with respect to the flow of the liquid coolant.

17. Apparatus for determining the operating conditions in a continuous metal casting machine as claimed in Claim 14, characterized in that the said thermal insulation material is a jacket surrounding the heat sensing detector and formed of slippery material to minimize sliding friction against the reverse surface of the casting belt.

18. Apparatus as claimed in Claim 15, characterized in that said thermal insulating material is a jacket which has an end portion and a mounting portion, a heat conducting metal sleeve mounted in the end portion of and being protected by said insulating jacket, said metal sleeve having a closed heat conducting tip which contacts the moving reverse surface of the belt, and a heat responsive, voltage generating element mounted within said jacket in heat conducting relationship with said metal sleeve.

19. Apparatus as claimed in Claim 18, characterized in that said mounting portion of said jacket is slidably mounted in a tube, said tube being mounted on said support means, with an internal spring disposed within said tube for urging said tip into firm contact with the moving reverse, cooled surface of the belt.

20. Apparatus as claimed in claim 18 or 19 characterized in that the end portion of said jacket is streamlined to present minimal interference to the flow of liquid coolant on the reverse belt surface.

21. Apparatus as claimed in claim 18, characterized in that said end portion of said thermal insulation jacket surrounds said heat conducting metal sleeve; and said voltage generating element is located within said sleeve adjacent to its closed tip to insulate said voltage generating element from cooling effects of the flow of liquid coolant, while conducting heat from the reverse surface of the belt through said metal tip to said voltage generating element.

22. Apparatus as claimed in any one or more of claims 14, 15 or 18, characterized in that said support means extends across near the reverse surface of the casting belt; and said series of heat sensing detectors are mounted on said support means and are located at spaced positions across the width of the casting belt near the casting region for monitoring the conditions of the belt coating as the molten metal is being cast.

23. Apparatus for determining the operating conditions in a continuous metal casting machine as claimed in claim 14, wherein there is a molten metal pool at the input to the casting region, characterized in that said series of heat sensing detectors are located in relative upstream and downstream positions in relation to travel of the casting beltnear the input to said casting region to span the desired location of the molten metal pool.

24. Apparatus as claimed in any one or more of claims 14, 15 or 18,wherein said machine is a twin-belt casting machine having an upper and a lower casting belt, characterized in that at least two series of heat sensing detectors are included;
first support means being associated with both belts and holding a first series of said detectors in contact with the moving, reverse, liquid-cooled surface of the lower belt near the casting region; and second support means holding a second series of said detectors in contact with the moving, reverse, liquid-cooled surface of the upper belt near the casting region.

25. Apparatus as claimed in claim 23, wherein there is a grooved roll having lands thereon supporting the casting belt near the input to the casting region, characterized in that said support means include at least one finger extending between the lands on said roll; and at least one heat sensing detector positioned in a groove between the lands of said roll and being mounted on said finger.

26. Apparatus as claimed in claim 23 or 25, characterized in that control means are provided for controlling the rate of infeed of molten metal into the input region of the machine; and circuit means interconnect said monitor means and said control means for automatically controlling the rate of infeed of the molten metal to keep the position of the molten pool within a desired operating range.

27. Apparatus as claimed in claim 25, characterized in that control means are provided for controlling the rate of infeed of molten metal into the input region of the machine; and circuit means interconnect said monitor means and said control means for automatically controlling the rate of infeed of the molten metal to keep the position of the molten pool within a desired operating range, said control means controlling the speed of belt travel for matching with the actual infeed of molten metal into the input region of the machine.

28. Apparatus as claimed in claim 27, characterized in that there is a second series of at least two heat sensing detectors mounted on said support means and positioned in laterally spaced relation across the width of the belt immed-iately downstream from the pool position for indicating the condition of the insulative coating material after the molten metal has come into contact with said material.