BG62536B1 - Device for the determination of the arrival of a liquid metal jet and the application of such type device - Google Patents

Abstract

The method includes the formation of an image by means of a light source (241) on a zone included between two surfaces, after which an image of the lighted object is formed and its light is converted into an electric quantity which is transmitted as functional information. The device contains and optical system for establishing the light consisting of an objective with adjustable focus, photoelectric converter (3), converter (2), comparator (5), buffer stage (6), supply (7) and light source (241). 8 claims, 6 figures

Description

Technical field

The invention relates to a device for detecting the flow of a liquid metal stream from a casting nozzle, for example, from a pot or channel nozzle.

The invention relates first and foremost to the detection of the presence of a light source generated by the flow of a jet of liquid metal.

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

BACKGROUND OF THE INVENTION

Known devices for controlling the level of liquid metal emitting infrared rays, i. of illuminating articles, containing a standard photoelectric element fitted with diaphragms bounding a defined area [1].

The operation of these devices is limited to the capture of liquid in a closed vessel. In fact, the image is formed by an elongated opening located in the diaphragm, projecting an area from the free surface of the tub. 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 flow, following a flat surface or even rectangular, such as when the level of the liquid metal in one pot rises.

The sensor of these known devices is known and adapted by a diaphragm that forms the aperture so that a portion of the effective surface is shortened, which reduces the efficiency of this sensor.

In addition, it is not intended to orient the known devices to the observation zone, where the passage of the illuminated objects is envisaged, by forming an image of the zone that allows for pre-regulation.

A system [2] for detecting the end of a jet of liquid metal is known, which enables the optical image of the observed area to be assembled on a photoelectric transducer, the zone being located below the stock of metal and bounded by four surfaces whose angles between them are such that the area of the image forms a rectangle; conversion into electrical quantity of light coming from metal as soon as it enters the area covered by the surfaces, transmission of electrical quantity representing functional information.

The known device imposes restrictions as it is intended to establish slag at the end of casting. Therefore, the location of the inflow of the metal jet is known since 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.

SUMMARY OF THE INVENTION

The invention allows to identify the first drop of metal coming from the casting nozzle. The casting tips are usually large in width, so 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 at a temperature higher than its melting point was not detected.

It is an object of the invention to remedy these drawbacks and to ensure the immediate passage of a luminous object.

To this end, the invention is as follows:

1 / Forming a real image with a light source; the real image allows for an installation and adjustment period with the following three stages: orientation, zoom adjustment and optical focus adjustment.

The real image materializes an area enclosed between two intersecting surfaces, where the angular surface of the acute angle formed by said surfaces is perpendicular to the direction of passage of the illuminated objects and of two other surfaces parallel to the direction of the intersecting directions. whereby the angle formed by the last surfaces is more obtuse than that formed by the first two surfaces and the exploited image area forms a rectangle.The observed area has a length greater than the width of the nozzle.

2 / Formation of an image of a luminous object as it enters the space enclosed between the 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 comprising a box-mounted optical and light-detecting system having a lens with adjustable focus and an electronic circuit board converter coupled to a photoelectric converter. The converter is connected to a comparator, which in turn is connected to a comparator, which in turn is connected to a single buffer step. The converter, the integrated proportional current generator, the comparator and the buffer step are connected to the 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 enables the transmission of continuous functional information, in particular information proportional to the current supplied by the converter. The device has a light source, the electronic board is located between the area for detecting the passage of illuminated objects and the light source / at least one rectangular opening is made in the electronic board / and is cooperated with the photoelectric transducer, the opening being adapted so that the rays of the light source to pass through it in such a way that the detection area is materialized, and the rays of the light source, after passing through the aperture, pass through the same optical system through that passes the light.

According to other features of the device, the intersection opening is adjacent to the photoelectric converter; a thermal protection means is connected to the light source; the thermal protection means comprises a sensor for converting the temperature into an electrical signal, a means providing the output data for the threshold value of the electrical signal, a threshold comparator, a buffer step and a relay; the sensor for converting the temperature into an electrical signal and the means providing the output for the electrical signal threshold value 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; a concave cover containing the light source is a means of cooling, in particular ribs; the light source consists of a halogen lamp and a thermal filter to allow only cold light to pass through.

Explanations of the annexed figures

The invention is illustrated by the accompanying figures, of which:

Figure 1 is a schematic view of the arrangement of a liquid metal projecting as an inclined jet from the nozzle of a casting pot;

FIG. 2 is the surface boundaries of the observation zone according to the invention; FIG.

Figure 3 is a diagram of the arrangement of the building blocks mounted on the electronic circuit board;

4 is a sectional view of one embodiment of the device according to the invention;

FIG. 5 is a sectional view of an apparatus according to the invention, which can be oriented according to the observation zone; FIG.

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

Examples of implementation

It should be emphasized that in the figures identical elements have the same designations. Thus, the designation 1 refers to the electronic circuit board and the designation 10 refers to the observation area.

The device shown in Figure 1 shows the observation zone 10 at one end of the optical axis 11 continuing the detector 20 according to the invention 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 limited by the surfaces 12, 13, 14 and 15 shown in Figure 2. The 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 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 observed area outside the intersection point 16 of the surfaces 12, 13, 14 and 15 forms the image surface 17 representing zone 10. The image surface 17 falls after optical adjustment on the photoelectric transducer 3, usually the photodiode shown in FIG. The 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 to equipotential bonds, denoted 0 '- 20', where 0 'represents the mass connection, D positive regulated power supply and 19' input of the unregulated positive power supply.

Converter 2 contains three resistors R1, R2 and R3, three capacitors Cl, C2 and C3, one operational amplifier IC1 and one potentiometer P2.

The resistance R1 is located between the equipotential bonds 2 'and D. The resistance R2 is connected to the bonds 0' and 4 '. Resistance R3 is coupled to links 5 'and 6'. Capacitor C2 is connected to terminals 0 'and 4' by their positive side; capacitor C3 is connected to terminals 5 ' and 6 '. The potentiometer P2 is connected to junctions 4 'and 2'. The potentiometer P2 is also connected via its slider to the 3 'link.

The IC1 operational amplifier has a non-inverting input connected to the 4 'link, while the inverting input is connected to the 5' and one output connected to the 6 'link.

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

The cathode K3 of the photodiode 3 and the anode A4 of the diode 4 are connected by an equipotential bond 5 '.

Comparator 5 contains two resistors R4 and R5, one capacitor C4 and one amplifier IC2.

The resistance R4 is connected to connections 3 'and 7'.

The resistance R5 is connected to connections 7 'and 8'.

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

The IC2 amplifier is connected to connections 6 'and 7' and 8 'respectively through its reversible input, its irreversible 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 contains three resistors R7, R8 and R9, two diodes D2 and D3, one transistor T2 and one relay R representing one coil and three circuit breakers.

The resistance R7 is connected to links 8 'and 9'.

The resistance R8 is connected to connections 9 'and 10'.

The resistance R9 is connected to junctions D and 12 '.

Transistor T2 is connected to junctions 0 ',

9 'and 10, respectively, to the electrodes of the emitter, base, collector.

Diode D2 is connected to junctions D and 10 'by its cathode K2 and its anode A2, respectively.

Diode D3 is connected to junctions 0 'and 1 D, respectively, by its cathode K and its anode A.

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

The three relay switches are connected respectively to connections 1 G 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 D1, fuse F, one protective zener diode TP1 and one regulator T1.

The RP resistance is related to the 17 'and 18' links.

The capacitor C5 is connected to the terminals 0 'and 16' on the positive side.

The capacitor C6 is connected to the terminals 0 'and D by the positive side.

Capacitor C 'is connected to terminals 0' and 16 '.

Capacitor C 'is connected to connections 0' and D.

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

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

The T1 controller is connected to the connections D by its output, 16 'by its input and 0' by its standard.

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

The power supply 7 comprises a divider connected electrically to the converter 2 and the comparator 5, the divider providing the required 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 housing 220 closed at one end by a cover 230 enclosing a washer 240 that closes radially the inner recess of the housing 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 on the other end by screws 270. A hollow cylindrical locking clamp 280 is mounted with screws 290 on the flange 260. The locking clamp 280 has at its one end a base 281 resting on the flange. The bracket encloses the lens with adjustable focus 300 and allows it to be locked by tightening screws 310 that pass through two drilled apertures 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 UV filter 340 on the lens 300. The device ends with an air tube 350 oriented in the direction of 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 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 of these aggressive magnetic, electrical, dust-related environmental effects in a plant are eliminated by tube 320, cover 230, air tube 350, and jacket 220.

Figure 5 illustrates a device 20 for detecting the presence of a liquid metal whose optical system and housing are identical to those given in Figure 4. Identical elements are identified by the same numeric symbols in both figures.

This device differs from that shown in Figure 4 in that it is not provided with a lamp 241 with a thermal filter located on the washer 240, which also carries the fuse socket 248. The potentiometer P, the lamp 241 and the fuse socket 248 are fitted in cover 230 with cooling fins 231. The lamp 241 has a sleeve 242 connected via cables 243 to the connector with base 244 mounted on the cover 230a by screws 245.

The device shown in FIG. 5 is also different from that in FIG. 4 in that the electronic circuit board has two horizontal rectangular slots 102 and 103 adjacent to the photodiode 3. The slit 102 is located above the photodiode 3, the slit 103 is under him.

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, has a protective thermal means 101 and 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 shown in Fig. 3 in that it has an electronic step providing a thermal protection means 101, a current generator 104, a power supply fuse 7 is connected to a connection 17 ', the capacitor C1 is removed and buffer step 6 is modified as follows: the resistance R9 is connected to the junctions 20 'and 2D, 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 respectively to the connections 16 'and 21' normally closed, 27 'and 26' normally closed, 27 'and 28' normally open. The relay coil 1 is connected to the connections 16 'and 10' respectively by its cathode and its anode.

Buffer step 6 is able to receive a means of protection, such as non-linear VDR resistance between the links 26 'and 27'.

The thermal protection means 101 consists of six resistors R15, R16, R17, R18, R19, R20, one transistor T3, one relay L2, consisting of a coil and a circuit breaker, one diode 5, one IC5 circuit comprising two operational amplifiers and one voltage standard as well as one IC4 thermal sensor.

The resistance R15 is connected to the connections 35 'and 36'.

The resistance R16 is connected to the junctions 0 'and 36'.

The resistance R17 is connected to the connections 33 'and 34'.

The resistance R18 is connected to the connections 34 'and 35'.

The resistance R19 is connected to the connections 32 'and 33'.

The resistance R20 is connected to the junctions 0 'and 32'.

The T3 transistor is connected to the connections O ', 36', 37 ', respectively to the electrodes emitter, base, collector.

The relay coil L2 is connected to the connections 16 'and 37'.

The relay switch L2 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 standard is connected to the O 'and 38' connections by its cathode and its anode.

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

The second IC5 operational amplifier is connected to the 3G, 34 ', 35' connections by its reversible input, its non-reversible input and its output.

The IC4 thermal sensor is connected to its 0 ', D, 3G connections by its negative power supply, its positive power supply and its rpnfod.

The generator 104 contains five resistors P10, Pl 1, P12, P13, P14, a protective diode TP2 and an operational amplifier IC3.

The resistance P10 is connected to the junctions 6 'and 23'.

Pile resistance associated with 23 'and 25' connections.

Resistance P12 is connected to junctions 4 'and 22'.

Resistance P13 is connected to connections 22 'and 24'.

Resistance P14 is connected to the connections 24 'and 25'.

The protective diode TP2 is connected to the connections 25 'and 0' by its cathode and its anode, respectively.

The IC3 operational amplifier is connected to the 22 ', 23' and 24 'connections of 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 of the IC5 are connected respectively to the connections D and 0 '.

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

As soon as the first drop of metal reaches the observation zone 10, which has a length substantially larger than the width of the tip 60, the detector 20 converts light from the liquid metal to electrical magnitude, and then transmits it. In this way, information about the receipt of the metal is transmitted in such a way that it moves the intended equipment at the right moment.

As it can 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 the zone 10, which is longer than the width of the nozzle 60, to obtain a repeatability of the weight of the metal, resulting in a constant amount, thereby avoiding excess metal thickness for the details obtained by casting.

When the device has a lamp 241, it can be adjusted before the liquid metal arrives. 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 power switch of the lamp 241, with which the latter goes out.

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

Claims (8)

Claims 1. A device for detecting the flow of liquid metal, including a housing mounted in a casing, in particular optical, for detecting light coming from a monitored area between at least two intersecting surfaces, the system comprising a lens with adjustable focus on an electronic board, one converter connected electrically to a photoelectric converter, the converter connected to a comparator, which in turn is connected to a buffer step, the converter, the comparator and the buffer step being connected to one power supply, characterized in that the device also includes a light source such as the electronic circuit board located between the passage of passage of the flow of liquid metal and the light source has at least one rectangular opening near the photoelectric transducer, representing the shape of the exploited area of the image of the observed object, i. rectangular, the aperture of the electronic circuit board being adapted so that the rays of the light source pass through it so as to materialize the area of establishment by forming a real image of the aperture, the rays of the light source passing through the aperture through the same optical system through which the transmitted light passes. A device according to claim 1, comprising a proportional current generator for transmitting continuous functional information proportional to the current supplied by the converter. A device according to claim 1, wherein the passage opening is adjacent to the photoelectric converter. A device according to any one of claims 1 to 3, wherein a thermal protection means is connected to the light source. 5. A device according to claim 4, characterized in that the thermal protection means comprises a sensor for converting the temperature into an electrical signal, a means providing a certain threshold value of the electrical signal, a threshold comparator and a relay, such as the sensor for converting the temperature into an electrical signal and the means providing the threshold value of the electrical signal are connected to one of the comparator inputs and the relay is connected to the output of the threshold comparator by a buffer Palo and the light source. A device according to any one of claims 1 to 5, in which the concave cover containing the light source has a cooling medium, in particular ribs. An apparatus according to any one of claims 1 to 6, wherein the light source comprises a halogen lamp and a thermal filter 10 to allow only cold light to pass through. Use of the device according to any one of claims 1 to 7 for determining the flow of the first drop of liquid metal stream coming from a casting pot through a 5 wide-spout nozzle to obtain metal parts of uniform weights.