BG99492A - Method and device for establishing the passing of a lighted object, e.g. of the liquid metal type, and the use of the device - Google Patents

Abstract

The method involves forming an image by means of a light source (241) on an area (10) covered between two surfaces, after which an image of the luminous object is formed and its light is converted into an electrical quantity which is transmitted as functional information. The device comprises an optical light detection system consisting of an adjustable focus lens, a photoelectric transducer (3), a converter (2), a comparator (5), a buffer stage (6), a power supply (7) and a light source (241). .

Description

The present invention relates to a method for detecting a rise in the value of a stream of metal coming from a casting nozzle, for example, from a pot or channel nozzle.

The invention relates, in particular, to a method for detecting the presence of a light source generated by a stream of liquid metal.

The invention also relates to a device allowing the use of one method for detecting the passage of illuminated objects, such as, for example, a jet of liquid metal.

Known devices for controlling the level of liquid metal emitting infrared rays, i. of illuminated objects, contain a standard photocell equipped with diaphragms bounding one defined area / see. for example document No. PPA-A-2 286 373 /.

The operation of these devices is limited to the capture of liquid in a closed vessel. In fact, the image is formed by means of an elongated opening located in the diaphragm, projecting an area from the free surface of the bath. Therefore, a vertical displacement of the entire surface of the bath is established. Such a device is not able to systematically detect the flow of a single stream of metal, because in this situation, the metal does not proceed by following a flat surface or even rectangular, as in the level of liquid metal in a pot.

Moreover, the sensor of these known devices is known and adapted by a single diaphragm that forms the opening, so that one, part of the effective surface is shortened, which results in a decrease in the efficiency of this sensor.

In addition, no orientation of the known devices is contemplated to the observation zone, where the passage of the illuminated objects is envisaged, by forming an image of said zone, which permits an advance adjustment.

Document E-A-3 129 217 A1 discloses a system for detecting the end of a jet of liquid metal, which allows the system to:

1 / Compiling an optical image of the monitored area on a photoelectric transducer, said area being located under a stock of metal and bounded by four surfaces whose angles between them are such that said image area forms a rectangle.

2 / Conversion into electrical magnitude of light coming from the metal as soon as it enters the area covered by said surfaces.

3 / Transmission of the electrical quantity representing the functional information.

The known device imposes restrictions since it was intended to establish slag at the end of the casting. Therefore, the location of the inflow of the metal jet is known as it falls vertically below the pot, which does not pose a problem with respect to the size and shape of the area observed. If it is rectangular here, this is due to the use of a ribbon camera rather than a geometric choice, depending on the location of the metal.

The invention, in turn, permits the identification of the first drop of metal coming from the casting nozzle. The casting tips are usually large in width, therefore, the location of the metal inlet is not known in advance.

Therefore, it is necessary to observe an area of size and geometric shape, covering all possible points at which metal can enter.

It would be very serious if the entry of metal was not detected at a temperature higher than its melting point.

The invention is intended to eliminate these disadvantages and to ensure the immediate detection of the passage of a luminous object.

For this purpose, the method according to the invention consists in:

1 / Formation of a real image using a light source; the actual image allows for an installation and adjustment period with the following three steps:

- orientation

- adjust the magnification

- Adjusting the optical focus.

The real image materializes an area enclosed between two intersecting surfaces, where the angular surface of an acute angle formed by the aforementioned surfaces is perpendicular to the direction of passage of the illuminating objects and of two other surfaces parallel to the directions of the intersecting directions. which is the angle formed by the latter surfaces is blunter than that formed by the first two surfaces, and said exploited image area forms a rectangle.

The observation area has a length greater than the width of the tip.

2 / Forming a single image of a luminous object when it enters the space enclosed between said two intersecting surfaces.

3 / Electrical conversion of light coming from the image as soon as it enters the area covered by the surfaces.

4 / Transmission of the electrical quantity representing the functional information.

According to other indications:

- the light is converted into electrical voltage, which is amplified before it is transmitted.

The invention also relates to a device which allows the application of the method described above, comprising, mounted in a box, an optical and light detection system having an adjustable focus lens and, on an electronic circuit board, a converter coupled to a photoelectric converter , the converter itself is connected to a single comparator, which in turn is connected to a single buffer step. The converter, integrated proportional current generator, comparator and buffer step are connected to a single power supply. The transducer represents the shape of the operated area of the image of the observed object. The observation area has a certain length depending on the width of the observation area. The current generator allows the transmission of continuous functional information, in particular one information proportional to the current supplied by the converter. The device has a single light source, the electronic board being located between the area for detecting the passage of illuminated objects and the light source (at least one rectangular aperture is made in the electronic circuit board) and cooperating with the photoelectric converter, the aperture being adapted so that the rays of the light source to pass through it in such a way as to materialize the detection area, such that the rays of the light source, after passing through the aperture, pass through the same optical light a system through which the said light passes.

According to other features of the device:

- the intersection is adjacent to the photoelectric converter,

- one thermal protection device is connected to the light source,

- the thermal protection means contains one sensor for converting the temperature into an electrical signal, one means providing the output data for the threshold value of the electrical signal, one threshold comparator, one buffer step and one relay,

- the temperature signal transducer in the electrical signal and the means providing the output for the electrical signal threshold are connected to each comparator input,

- the relay is connected to the output of the buffer step, which in turn is connected to the output of the threshold comparator and to the light source,

- the concave cover containing the light source is a means of cooling, in particular ribs,

- the light source consists of one halogen lamp and one thermal filter in order to pass only the cold light.

An example of the application of the invention will be described below with the accompanying drawings which:

- & -

- Fig. 1 schematically illustrates the placement of liquid metal emerging as an inclined jet from a casting pot tip;

FIG. 2 illustrates the surfaces limiting the observation zone according to the invention; FIG.

- Fig. 3 is a diagram of the arrangement of the building blocks mounted on the electronic circuit board;

FIG. 4 'illustrates one section of one embodiment of the device according to the invention;

- FIG. 5 is a sectional view of a device according to the invention, which device can be oriented depending on the zone of observation;

6 is a diagram of another embodiment of the elements mounted on the electronic circuit board corresponding to the device of FIG. 5.

First of all, it should be emphasized that in the drawings identical elements have the same designations. Thus, designation 1 refers to the electronic circuit board and designation 10 refers to the observation area.

The device illustrated in Figure 1 illustrates the observation zone 10 at one end of the optical axis 11 continuing the detector 20 according to the invention is supported by a support 21.

The rectangular shaped observation zone 10 extends horizontally at the level of one casting pot 30 of liquid metal over one overflow 40 with channel 50 and below the tip 60 of pot 30.

The observation zone 10 is bounded by the surfaces 12, 13, 14 'and 15 given in Figure 2. The subunit surfaces intersect at point 16 on the optical axis 11, in particular at the optical center of the lens.

Two of the intersecting surfaces 12, 13 are close to horizontal, and the other two, 14 and 15 are vertical. The axis 11 is the axis of symmetry of these surfaces.

The axis 11 is perpendicular to the passage of the jet of liquid metal.

The observation area outside the intersection point 16 of the surfaces 12, 13, 14 and 15 forms the image surface 17 representing the area 10. The image surface 17 falls, after optical adjustment, on the photoelectric transducer 3, usually the photodiode 3 in Figure 3. This photodiode 3 converts the received light flux into electrical current. The photodiode is connected to a converter 2, connected to a comparator 5, connected to a buffer step 6. The electrical supply 7 is connected to a comparator 5 at the buffer step of the bis converter 2. A protection diode 4 is connected in parallel to the photoelectric converter. 3.

The electronic elements are connected by equipotential connections denoted by 0 * to 20 *, where 0 * represents the connection of ground and 1 '- the positive regulated power supply and the 19' input of the unregulated positive power supply.

Converter 2 contains three resistors. Bl, B2 and _{λ λ} 3, three capacitors Cl, C2 and C3, one operational amplifier IC1 and one potentiometer P2.

The resistance P1 is located between the equipotential bonds 2 'and 1'. The P2 resistance is related to the bonds 0 'and 4'. B3 resistance is connected to 5 'and 6' junctions. Capacitor C2 is connected to terminals 0 * and 4 'by their positive side; capacitor C3 is connected to connections 5 'and 6' _{o The} potentiometer P2 is connected to connections 4 'and 2'. Said potentiometer P2 is also connected by means of its slider to link 3 '.

The IC1 operational amplifier has a non-reversible input connected to a 4 'connection, while the reversible input is connected to a 5' and a single output connected to a connection 6 '.

This structure of the converter 2 'allows to minimize the current of the photodiode 3 in the dark. The anode A3, said photodiode 3 and the cathode K4 of diode 4 are connected by an equipotential bond 4 '.

The KT cathode of the photodiode 3 and the anode A4 of the diode 4 are connected by an equipotential bond 5 '·

Comparator 5 contains two resistors 54 and £ 5, one capacitor C4 and one amplifier IC2.

The resistance 54 is connected to the connections 3 'and 7'.

The resistance 55 is connected to the connections 7 'and 8'.

The capacitor C4 is connected to terminals 0 'and 3' on the positive side.

The IC2 amplifier is connected to 6 'and 7' and 8 'through its reversible input, its non-reversible input and its output.

Comparator 5 compares the output voltage of converter 2 with the output voltage determined by the potentiometer P2.

The buffer stage comprises three resistors 57, 58 and 59, two diodes D 2 and T) 3, one transistor T2 and one relay 5 representing one coil and three circuit breakers.

The resistance «7 e connected p connections 8 ' and 9 '. The resistance 58 e connected p connections 9 ' and 10 ». The resistance 59 e connected p connections 1 ' and. 12 '. Transistor T2 is connected to links 0 ', 9 ' and 10, respectively

but to the electrodes emitter, base, collector.

Diode D 2 is connected to connections 1 'and 10', respectively, through its cathode K2 and its anode A2.

The diode ί 3 is connected to junctions 0 'and 11' by its cathode K and its anode A. respectively.

The relay coil is connected to connections 1 'and 10'.

The three relay switches are connected respectively to connections 11 'and 12' normally closed, 13 'and 14' normally closed, 13 'and 15' normally open.

Power supply 7 consists of a resistance PP, four capacitors C5, C6, C ', C', one diode 31, a fuse P, one protective zener diode TP1 and one regulator T1.

PP resistance is related to connections 17 'and 18'.

The capacitor C5 e associated with connections 0 ' and 16 'of the positive- the body side. The sun is in the sun C6 e associated with connections 0 ' and 1 'by positive- the other side. The capacitor C ' e associated with connections 0 ' and 16 '. The capacitor with ' ^! 1 is connected with links 0 > and 1 '.

Diode D4 is connected to 16 'through cathode and 17' through anode.

Fuse P is connected to connections 18 'and 19'.

The T1 controller is connected to the connections 1 'through its output, 16' through its input and 0 'through its reference.

The TR1 protection diode, which acts as a stop ', is connected to terminals 0' and 17 '.

The power supply 7 comprises a divider electrically connected to the converter 2 and the comparator 5, said divider providing the necessary voltage in the idle state of the converter 2 and the reference voltage of the comparator 5.

Figure 4 illustrates the device 20 supported by the locking system 21. The device 20 consists of a hollow cylindrical casing 220 closed at one end with a cover 230 enclosing a washer 240 which closes the inner recess of the casing 220. The washer 240 supports the potentiometer P2 .

The cover 230 is fixed to the housing with screws 250. With its second end, the housing 220 encloses the electronic circuit board 1, located radially on the housing 220 in the image surface 17. A flange 260, representing a hollow cylinder, has a diameter smaller than the diameter of the housing and is mounted at the second end with screws 270. A hollow cylindrical locking clamp 280 is mounted with 2S0 screws on the flange 260. The locking clamp 280 has at its one end a base 281 resting on the flange. Said bracket encloses the lens with adjustable focus 300 and allows the latter to be locked by tightening screws 310 which pass through two drilled holes at the free end of the locking bracket 280.

The lens 300 and the bracket 280 are housed in a protective tube 320 mounted on the base 281 of the bracket 280 through a connector 321 and screws 330. The tube 320 has a protective ultraviolet filter 340 on the lens 300. The device ends with an air tube 350 oriented in the direction of the passage of a jet of liquid metal. The device 20 is a cylinder whose axis merges with the optical axis 11.

The housing 220 and the tube 320 are made of metal that has a magnetic permeability and electrical conductivity with a level capable of providing protection against magnetic and electrical interference.

The lid 230 and the air tube 350 protect the device 20 from various types of dust. All these aggressive effects - magnetic, electrical, dust, depending on the environment in one plant - are eliminated by the tube 320, the cover 230, the air tube 350 and the housing 220.

Figure 5 illustrates a device 20 for detecting the presence of a liquid metal whose optical system and skin ~ * D - L-.

· - i - - .., / _: c and ί> 'and. t_

- 11 times are identical to those given in figure 4, identical elements are marked with the same numerical designations in both figures.

This device differs from that of Figure 4 in that it is provided with a lamp 241 with a thermal filter located on the washer 240, which also carries the socket 248. The potentiometer P, the lamp 241 and the socket 248 are placed in the cover 230. with cooling fins 231. The lamp 241 has a single sleeve 242 connected via cables 243 to a base connector 244 mounted on the cover 230a by screws 245.

The apparatus of Figure 5 also differs from that of Figure 4 in that the electronic board has two horizontal rectangular slots 102 and 103 adjacent to the photodiode 3. The slot 102 is located above the photodiode 3, the slot 103 is below it.

The slots 102 and 103 are slanted, with the large opening located at the lamp 241, the small opening facing the viewing area 10. The electronic circuit board 1, in addition to the converter 2, the comparator 5, the buffer step 6 and the power supply 7, also has a protective thermal means 101 and one current generator 104.

Figure 6 illustrates the arrangement of the elements mounted on the electronic circuit board 1 corresponding to the device shown in Figure 5.

This device differs from that given in Figure 3 in that it has an electronic step providing one means of thermal protection 101, one generator of current 104, the power supply guard P 7 is connected to the connection 17 ', the capacitor 01 is removed and buffer step 6. is modified as follows: the resistance R9 is connected to the connections 20 'and 21 *, the diode D3 is connected to the connections 0' and 20 ', respectively to its cathode and its anode. The three relay switches R1 are connected

- 12 respectively with connections 16 'and 21' normally closed, 27 'and 26' normally closed, 27 'and 28' normally open. The relay 1 coil is connected to the connections 16 'and 10' by its cathode and its anode.

Buffer step 6 is able to accommodate a means of protection, such as non-linear VUR resistance between connections 26 'and 27'.

The thermal protection means 101 consists of six resistors 515, D16, 517, 518, B19, 520, one transistor T3, one relay L2 consisting of one coil and one circuit breaker, one diode 5, one integrated circuit IC5 containing two operational amplifiers and one voltage reference, as well as one thermal IC4 sensor.

The resistance RL5 e connected p the connections 35 ' and 36 '. The resistance RL6 e connected p the connections 0 ' and 36 *. The resistance Q17 e connected p the connections 33 ' and 34 '. The resistance 518 e connected p the connections 34 * and 35 '. The resistance 519 e connected p the connections 32 ' and 33 *. The resistance 520 e connected p the connections 0 ' and 32 '.

The TC transistor is connected to the connections 0 ', 36', 37 'respectively to the electrodes emitter, base, collector.

The relay b2 is connected to connections 16 'and 37 *.

The relay switch b2 is connected in series to the supply circuit of the halogen lamp through connections 30 'and 29' ·

Diode 5 is connected to connections 16 'and 37' by its cathode and its anode, respectively.

The voltage reference is connected to the 0 'and 38' connections of your cathode and your anode, respectively.

The first IC5 operational amplifier is connected to 32 *, 38 ', 33' connections, respectively, with its reversible input, its non-reversible input and its output.

- 13 The second IC5 operational amplifier is connected to its 31 ', 34', 35 'connections, respectively, with its reversible input, its non-reversible input and its output.

The IC4 thermal sensor is connected to the O ', 1', 31. 'connections, respectively, for its negative power, its positive power and its output.

Current generator 104 contains five resistors P10, P11, P12, P13, P14, one protective diode TP2 and one operational amplifier IC3.

P10 resistance is connected to 6 'and 23' ·

The P11 resistance is connected to 23 'and 25'.

Resistance P12 is linked p connections 4 '· * and 22 ' • Resistance P13 is linked p the connections 22 ' and 24 '. Resistance P14 is linked p the connections 24 ' and 25 '. The protective diode TP2 is connected p the connections 25 ' and 0 ', con- with your cathode and your anode.

The IC3 operational amplifier is coupled to its 22 'and 23' and 24 'connections, its reversible input, its non-reversible input and its output.

The positive supply and the negative supply of the IC4, IC2, and IC3 amplifiers of the IC4 sensor and IC5 are respectively connected to the connections 1 'and 0'.

The operation of the device is as follows: the pot 30 is inverted, the liquid metal is poured into a jet from the nozzle 60 into the overflow 40 and then flows into the channel 50.

As soon as the first drop of metal reaches the observation area 10, which has a length substantially larger than the width of the tip 60, the detector 20 converts light from the liquid metal into electrical quantity, amplifies said electrical quantity, and then transmits it. Thus, the receipt information for the metal is transmitted in such a way that it moves the intended facility at the right time.

As it may be noted, it is very difficult to accurately account for the exact moment of arrival of the metal.

Due to the width of the nozzle 60, the metal may flow either on one side or in the middle of the nozzle 60, so that the place of fall of the jet will not be constant but will be displaced. This interferes with the uniformity of the leakage of the liquid metal and causes changes in the weight of the cast metal parts. Therefore, the invention allows the geometry of zone 10, which is longer than the width of the tip 60, to obtain a repeatability of the weight of the metal, resulting in a constant amount, thereby avoiding excess metal thickness for the parts obtained by casting.

When the unit has a single lamp 241, it can be adjusted before entering the liquid metal. When the lamp is lit, the light beams pass through the slots 102 and 103 and materialize by depicting the slits on the sweat 30 of the observation area 10. The device is centered by superimposing the slots 102 and 103 on the observed area. When the lamp is lit for a long time, it emits heat, which is removed by the ribs 231. When the time during which the lamp is lit is too long and the temperature rises, the protective thermal means 101 activates the switch of the electrical supply of the lamp 241, with which the glacial is extinguished.

Alternatively, the monitoring zone 10 may be located elsewhere, for example at the end of channel 50.

Claims (5)

Patent Claims 1) forming an optical image of a monitored zone (10) of a photoelectric transducer, said region located below the tip (60) being limited by two intersecting surfaces (12, 13), whose angular surface of the edges formed by said surfaces the angle is perpendicular to the direction of passage of the metal and to the other two surfaces (14, 15) parallel to the direction of passage of the metal, the angle formed by the last two surfaces being blunter than the angle formed by the first two surfaces atata area of the image forming rectangle, 1.- A method for determining the receipt of a single stream of liquid metal coming from a casting nozzle (60), which method consists of: A device enabling the application of the method according to one of claims 1 to 3, comprising, in a casing, a system, in particular optical, and for detecting light, having a single lens with an adjustable focus or a fixed lens and, electronic board / 1 / located one converter / 2 / connected to one photoelectric converter / 3 /, said converter / 2 / connected to one comparator / 5 / which is connected to one buffer step / 6 /, such as the converter, the comparator and the buffer step are connected to a power supply (7), characterized with the said device also comprising one light source / 241 / and the electronic circuit board / 1 / is located between the area / 10 / to detect the passage of illuminated objects and the light source / 241 / into the electronic circuit board / 1 / at least one rectangular aperture is made and it cooperates with a photoelectric converter representing the shape of the operated area of the image of the observed object, i. rectangular, the converter opening / 3 / being adapted so that the rays of the light source / 241 / pass through it in order to materialize the area of establishment, such as the rays of the light source / 241 / after passing through the opening, pass through through the same optical system through which the transmitted light passes. A device according to claim 9, comprising a proportional current generator (104) designed to transmit continuous functional information proportional to the current supplied by the converter (3). 11. The device of claim 9, wherein the passage opening is adjacent to the photoelectric converter (3). A device according to any one of claims 9 to 11, wherein a thermal protection means is connected to the light source (241). 13. - Device according to the preceding claim 12, characterized in that the thermal protection means comprises a sensor for converting the temperature into an electrical signal, one means providing a certain threshold value for the electrical signal and one threshold comparator and one relay ; the sensor for converting the temperature into an electrical signal and the means providing the output threshold data for the electrical signal are connected to one of the comparator inputs, the relay is connected to the output of the threshold comparator by a single buffer step and the light source. A device according to any one of claims 9 to 13, wherein the recessed lid (230) comprises a light source (241) constitutes a cooling medium (231), in particular ribs. A device according to any one of claims 9 to 14, wherein the light source (241) consists of a halogen lamp and a thermal filter in order to pass only the cold light. Application of the device according to one of claims 4 to 15 for determining the receipt of the first 2 - A method for detecting the passage of at least one illuminated object according to claim 1, characterized in that it comprises a preliminary step, which consists in the formation of a single image through a single light source (241), materializing one zone (10) encompassed between two intersecting surfaces (12, 13), the angular surface of which at an acute angle formed by said surfaces is perpendicular to the direction of passage of the illuminating objects. 2 / conversion of the electrical quantity of light coming from the metal as soon as it enters the zone / 10 / covered by said surfaces, 3. The method of claim 1 or 2, wherein the light is converted to an intensity, then to a voltage that is amplified and converted to an electric current. 3 / transmit the electrical quantity representing the functional information, characterized in that the monitoring zone / 10 / has a longer length than the width of the casting nozzle / 60 /, A device for applying a method according to one of claims 1 or 3, comprising, in a casing, a system, in particular optical and detecting light, comprising a lens with adjustable focus / 300 / and on an electronic circuit board / 1 / one converter / 2 / connected to one photoelectric converter / 3 /, the comparator itself / 5 / connected to one buffer step / 6 /, the converter, comparator and buffer step connected in turn to one power supply / 7 /, characterized by with the fact that the photoelectric converter / 3 / ex represents the form of the image of the observation area having the intended length depending on the shape of the observed area. 5. Apparatus according to claim 4, characterized in that the power supply (7) has a divider connected to the converter (2) and a comparator (5), said divider providing the voltage and output voltage of the converter necessary for the state of rest. comparator / 5 /. 6. Device according to claim 4 or 5, characterized in that a protective diode (4) is connected in parallel with the photoelectric converter. Device according to one of Claims 4 to 6, characterized in that the housing is closed with a lid at one end and that one air tube is mounted at its other end and is oriented in the direction of passage of the illuminated objects. Device according to one of Claims 4 'to 7, characterized in that the housing is made of metal having a magnetic impermeability and electrical conductivity with a level capable of providing protection against magnetic and electrical disturbances. - 5 drops of a single stream of liquid metal coming from a casting pot through a large width nozzle to obtain metal parts with uniform weights.