FIELD OF THE INVENTION

The present invention relates to a system for sensing the blooms in end stoppers and intermediate stoppers of continuous caster in steel plants. More particularly, the present invention relates to a photosensor based system for sensing the blooms in end stoppers and intermediate stoppers of four strands bloom caster under very difficult site conditions. The system of the present invention is a simple, low cost but highly reliable optics based system for sensing the blooms in end stopper and intermediate stoppers in continuous casting shop of steel plant in constrained operating conditions like: sensing can not be possible due to movement of trolley over blooms, bloom movement in all three direction which influence the optical sensor, interference from bloom light radiation of neighboring strands, interference of mechanical wire rope, water, Grease rubber pipes in the line of sight, falling of water or falling of scale powder/ dust etc. The sensors are used to convert light signal of bloom into electrical signals. The bloom sensing is implemented in two units e.g. (1) sensing unit and (2) output unit, wherein sensor output is used for stopping the roll table before hitting to stoppers subsequently lifting the roll table and placing the bloom on rack for further transportation in either left or right cooling beds.

BACKGROUND ART

In Continuous casting shop conventional type photosensors are usually installed but they could not sense bloom in any strand reliably since they are affected by the radiation of bloom either due to light of neighboring strand or bloom being transported over them. None of the existing technologies dealt with the problem faced in typical site condition for detection of a bloom strand in continuous caster. The earlier bloom detection was carried out by using brush type sensors for tracking the blooms in different zones after Gas cutting area which suffered from problems like : (1) These sensors were often giving problems like bending of brush, their straightening and replacing and other fatigue activities involved, (2) Deposition of carbon particles, (3) If problem occurred during casting, then its rectification could be possible only after the completion of casting.

The conventional photosensors fails to detect exactly an approaching bloom before they physically hit an end stopper due to light propagating from different sources and incident on sensor leading to wrong signal. Thus it may not be possible to stop roll table before a moving bloom hits the end stopper due to lack of proper detection of an approaching bloom causing bottle- neck for continuous operation of the caster.

There has thus been a need in the art to developing a system for bloom sensing in end stoppers and intermediate stoppers in continuous caster to transport the beam on roll table and to transfer to cooling bed in safe and reliable manner avoiding any unwanted hitting of bloom with the end/intermediate stoppers affecting continuous operation of plant and the productivity in continuous caster.

OBJECTS OF THE INVENTION

The basic object of the present invention is thus directed to providing a simple, low cost but highly reliable optics based system for bloom sensing in end stoppers and intermediate stoppers in narrowly spaced four strand continuous caster under difficult site conditions.

A further object of the present invention is directed to providing a system for bloom sensing in end stoppers and intermediate stoppers in four strand continuous caster to precisely and reliably sense location of a bloom of each strand on roll table and transporting it to cooling bed without any collision with stoppers by stopping roll table in exact time, facilitating lifting roll table, placing the bloom on rack for further transporting of bloom in either left or right cooling beds.

A still further object of the present invention is directed to providing a system for bloom sensing in end stoppers and intermediate stoppers in four strand continuous caster adapted to avoid error in sensing radiation of bloom either due to light of neighboring strand or bloom transporting over them.

A still further object of the present invention is directed to providing a system for bloom sensing in end stoppers and intermediate stoppers in four strand continuous caster wherein focusing hoods are of different length and cross section for pinpointing the object and sensing unit is adapted not to receive the radiation of bloom which is lifted for shifting.

A still further object of the present invention is directed to providing a system for bloom sensing in end stoppers and intermediate stoppers in four strand continuous caster wherein the sensors would be sensitive to visible and higher intensity infra red radiations.

A still further object of the present invention is directed to providing a system for bloom sensing in end stoppers and intermediate stoppers in four strand continuous caster wherein the sensing unit is adapted to sustain high degree of vibration and sustain high environmental temperature without cooling.

A still further object of the present invention is directed to providing a system for bloom sensing in end stoppers and intermediate stoppers in four strand continuous caster adapted where bloom sensing can not be possible due to obstruction in the line of site by the movement of trolley over blooms.

A still further object of the present invention is directed to providing a system for bloom sensing in end stoppers and intermediate stoppers in four strand continuous caster adapted to sense bloom movement in all three direction which influence the optical sensor.

A still further object of the present invention is directed to providing a system for bloom sensing in end stoppers and intermediate stoppers in four strand continuous caster adapted to avoid interference from bloom light radiation of neighboring strands.

A still further object of the present invention is directed to providing a system for bloom sensing in end stoppers and intermediate stoppers in four strand continuous caster adapted to perform precise sensing avoiding interference of mechanical wire rope, rubber pipes of water, Grease etc. in the line of sight.

A still further object of the present invention is directed to providing a system for bloom sensing in end stoppers and intermediate stoppers in four strand continuous caster adapted to perform precise bloom sensing in spite of presence of adverse site conditions like falling of water or falling of scale powder/ dust and the like.

SUMMARY OF THE INVENTION

The basic aspect of the present invention is thus directed to a system for sensing blooms in end stopper and intermediate stoppers in continuous casting in steel plant comprising:
a sensing unit sensitive to visible and higher intensity infra red radiations and adapted to convert light signal of bloom into electrical signals ; and

an output unit cooperate with said sensing unit and adapted for stopping the roll table before hitting to stoppers and subsequently lifting the roll table and placing the bloom on rack for further transportation.

A further aspect of the present invention is directed to a system for sensing blooms which is adapted to operate in casting shop of steel plants in the presence of a. bloom movement in all three direction which influence the optical sensor, b. interference from bloom light radiation of neighboring strands, c. interference of mechanical wire rope , rubber water Greece pipes in the line of sight, d. falling of water e. falling of scale powder/ dust.

A still further aspect of the present invention is directed to a system for sensing blooms comprising : photosensor unit to sense the very narrow focusing tube preferably about (150 mm (L) x 20 mm (dia) ) with aperture control facility;
focusing hood of different length and cross section for pinpointing the object and sensing unit adapted such as not to receive the radiation of bloom which is lifted;
sensor related to bloom strand 1,2,3,4 adapted such as not to receive the radiation of own bloom which is lifted and passing under the process of shifting.

A still further aspect of the present invention is directed to a system for sensing blooms comprising a small photo voltage as low as about 10 mV voltage transmitted to about 80 m distance through unscreened wires.

According to yet another aspect of the present invention is directed to a system for sensing blooms comprising sensing the bloom in the presence of background blooms in cooling bed with the one sensing unit located about 10 mm from hot bloom (1100 C), heat resistant cable 1 m used for connecting sensing element particularly for strand 1 intermediate end stopper.

Advantageously, said system for sensing blooms is free of any external cooling with the sensor adapted to receive heat radiation intermittently from all side.

A still further aspect of the present invention is directed to a system for sensing blooms wherein said sensing unit comprises:

a. Sensitive to visible and higher intensity infra red radiations.

b- Indications at top and backside for object present.

c- Pilot beam (mounted left hand side on the
focusing hood of photosensor for pin pointing focusing at a distance of
about 2 m. beam spreading at about 6 m distance. (1: 1.1 maximum
allow )

d- i Adjustable in horizontal plane in 360 degrees and in vertical plane
with 300 degrees with a accuracy of 0.5°.
ii mounted preferably on steel plant environment
e- adaptability to sustain high degree of vibration of 10 mm with 20 Hz. and sustain up to 85° C environment without cooling.
f- Focusing hood of different length and cross section for pinpointing the object and sensing unit should not receive the radiation of bloom which is lifted .
A still further aspect of the present invention directed to said system for sensing blooms wherein said output unit comprises power supply and signal processing units.

According to yet another aspect of the present invention is directed to said system for sensing blooms wherein said output unit comprises:
a- Relay output ;
Open collector transistor ;
Opto coupler ;
Visual indicator ;
Volume control Buzzer ;
b- Response < 2 ms for relay and < 0.3 ms for transistor and optocoupler .
c- Remote Test facility for entire two units along with cable.

The objects and advantages of the present invention are described in further details with reference to the following non limiting accompanying drawings.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES

Figure 1: is the schematic illustration of isometric view of the bloom sensing system along with the photosensor means according to the present invention.

Figure 2: is the schematic illustration of end stoppers and Brush sensors used in the system.

Figure 3a: is the schematic illustration of location of photosensors(SAILPHOS) at end/intermediate stoppers the four strand caster and roll table showing the according to the present invention.

Figure 3b: is the schematic illustration of an embodiment of the focusing hood of photo sensors with provision for adjusting in horizontal as well as vertical plane for focusing on object, which are used in the bloom sensing system according to the invention.

Figure 3c: is the schematic illustration of an embodiment of the system of the invention showing the location of the SAILPHOS sensors in bloom caster and the control unit in pulpit.
Figure 3(d): is the schematic illustration of the control unit cutting pulpit showing the output of SAILPHOS sensors used to control bloom movement in relation to IM/End stoppers.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING FIGURES

The present invention is directed to a system for bloom sensing in end stoppers and intermediate stoppers in continuous caster adapted to avoid hitting the stoppers and further transporting of the blooms in cooling bed in a reliable manner. The photosensor based sensing system is adapted to pinpointing focusing on object unaffected by the radiation from neighbouring blooms on four strand caster and also immune to radiation from bloom that is lifted and moved over the others for transporting to next stage of operation. More importantly, the photosensor based bloom sensing system according to the present invention is specially designed to perform safely and reliably for sensing the blooms in end stoppers and intermediate stoppers of four strands bloom caster capable of sensing bloom movement in all three direction which influence the optical sensor, under difficult site conditions such as interference from bloom light radiation of neighboring strands, interference of mechanical wire rope, water or grease pipes, various falling bodies at shop/site environment.

The sensors are used to convert light signal of bloom into electrical signals. Its output is used for stopping the roll table before hitting to stoppers subsequently lifting the roll table and placing the bloom on rack for further transportation in cooling bed. The bloom sensing system comprises two units:

1. Sensing Unit

2. Output Unit

The Sensing Unit
A photosensor unit designed for the system is able to sense object involving very narrow focusing tube (150 mm (L) x 20 mm (dia) ) with aperture control facility. Focusing hoods of photosensors are of different length and cross section for pinpointing the object and also not to allow sensing unit to receive the radiation of bloom which is lifted. Sensor related to bloom strand 1,2,3,4 are adapted not to receive the radiation of own bloom which is lifted and undergoing the process of shifting.

The sensing unit is sensitive to visible and higher intensity infra red radiations. It is capable of indications at top and backside for object present. The unit is provided with a Pilot beam mounted left hand side on the focusing hood of photosensor for pin pointing focusing at a distance of 2m. Sensor does not get activated with focusing pilot spot.

Due to metallic covering sheet and long focusing tube and powerful optics , the cleaning of dust may be carried out once in a year favouring ease of maintenance.

The focusing hood/tube of sensing unit is adjustable in horizontal plane in 360 degrees and in vertical plane with 300 degrees with a accuracy of 0.5°. The sensing unit is able to sustain high degree of vibration of 10 mm with 20 Hz. and can also sustain up to 85° C environment without cooling. Due to superior design adopted , no cooling by water or air is required . A Sensor receives heat radiation intermittently from all side.

Importantly, the sensors are capable of sensing the bloom in the presence of background blooms in cooling bed. Sensing unit is put 10 mm from hot bloom(1100 C) and heat resistant cable (1 m) is used for connecting sensing element particularly for strand 1 intermediate and end stopper. A small photo voltage as low as 10 mV voltage is transmitted to 80 m distance through unscreened wires.

The Output Unit

Output Unit or the Power supply and signal processing unit comprising Relay output with potential free contacts 2NO and 2 NC, involving open collector transistor, opto coupler, visual indicator and volume control buzzer, response time is <2ms for relay and 0.3ms for transistor and optocoupler. Remote test facility is provided for the entire two units alongwith cable.

Accompanying Figure 1 illustrates the schematic of bloom casting in 4 strands caster.

Accompanying Figure 2 illustrates bloom sensing through contact type brush sensors.

Accompanying Figure 3a illustrates that the Sensors are sensing the bloom arriving at End stopper, Intermediate stopper respectively according to the present invention under the typical site condition such as interference from bloom light radiation of neighboring strands, interference of mechanical wire rope, water, Grease rubber pipes in the line of sight, falling of water or falling of scale powder/ dust etc.

Accompanying Figure 3b illustrates the photosensor unit according to the present invention which is meant to sense the very narrow focusing tube preferably about (150 mm (L) x 20 mm (dia) ) with aperture control facility; focusing hood of different length and cross section for pinpointing the object and sensing unit adapted such as not to receive the radiation of bloom which is lifted; On the side of focusing hood, there is a focused light consisting of a convex and concave lenses. By sliding the lense the bright spot of LED (light emitting diode) can fall on object and it will ensuring the pin point focusing of sensor.

Accompanying Figure 3c illustrates the sensing of bloom in different strands.

Accompanying Figure 3d illustrates that Phototransistor T1 receives light energy and enables respective collector and emitter junctions undergoes low impedance and entire collector voltage is available as long as bloom is in front of sensor. The low level voltage is further amplified by A1 amplifier, while voltage due to surrounding light is rejected by comparator circuit A2 by comparing with the set value ( set value can be adjusted by 50 turn P2 potentiometer ) . The out put voltage of A2 actuate npn transitor which in turn actuate 12 volts relay RL. Normally open contacts of RL are connected to input circuit of PLC (Programmable logic controller).

It is thus possible by way of the present invention to providing a system for sensing blooms in end stoppers and intermediate stoppers in four strands continuous caster which is simple and cost effective yet reliable and is adapted to precisely sensing bloom in relation to stoppers in a strand for stopping the roll table before hitting to stoppers and subsequently lifting the roll table and placing the bloom on rack for further transportation, thus ensuring longer continuous operation of caster plant free of any bottleneck.

We Claim:

1. A system for sensing blooms in end stopper and intermediate stoppers in continuous casting in steel plant comprising:
a sensing unit sensitive to visible and higher intensity infra red radiations and adapted to convert light signal of bloom into electrical signals ; and
an output unit cooperate with said sensing unit and adapted for stopping the roll table before hitting to stoppers and subsequently lifting the roll table and placing the bloom on rack for further transportation.

2. A system for sensing blooms as claimed in claim 1 which is adapted to operate in casting shop of steel plants in the presence of a. bloom movement in all three direction which influence the optical sensor, b. interference from bloom light radiation of neighboring strands, c. interference of mechanical wire rope , rubber water Greece pipes in the line of sight, d. falling of water e. falling of scale powder/ dust f. sensing can not be possible due to movement of trolley over blooms.

3. A system for sensing blooms as claimed in anyone of claims 1 or 2 comprising : photosensor unit to sense the very narrow focusing tube preferably about (150 mm (L) x 20 mm (dia) ) with aperture control facility;
focusing hood of different length and cross section for pinpointing the object and sensing unit adapted such as not to receive the radiation of bloom which is lifted;
sensor related to bloom strand 1,2,3,4 adapted such as not to receive the radiation of own bloom which is lifted and passing under the process of shifting.

4. A system for sensing blooms as claimed in anyone of claims 1 to 3 comprising a small photo voltage as low as about 10 mV voltage transmitted to about 80 m distance through unscreened wires.

5. A system for sensing blooms as claimed in anyone of claims 1 to 4 comprising sensing the bloom in the presence of background blooms in cooling bed with the one sensing unit located about 10 mm from hot bloom (1100 °C), heat resistant cable 1 m used for connecting sensing element particularly for strand 1 intermediate end stopper.

6. A system for sensing blooms as claimed in anyone of claims 1 to 5 which is free of any external cooling with the sensor adapted to receive heat radiation intermittently from all side.

7. A system for sensing blooms as claimed in anyone of claims 1 to 6 wherein the sensing unit comprises:

a. Sensitive to visible and higher intensity infra red radiations.

b- Indications at top and backside for object present.

c- Pilot beam (mounted left hand side on the
focusing hood of photosensor for pin pointing focusing at a distance of
about 2 m. beam spreading at about 6 m distance. (1: 1.1 maximum
allow )

d- i Adjustable in horizontal plane in 360 degrees and in vertical plane
with 300 degrees with a accuracy of 0.5°.
ii mounted preferably on steel plant environment
e- adaptability to sustain high degree of vibration of 10 mm with 20 Hz. and sustain up to 85° C environment without cooling.
f- Focusing hood of different length and cross section for pinpointing the object and sensing unit should not receive the radiation of bloom which is lifted .
8. A system for sensing blooms as claimed in anyone of claims 1 to 7 wherein said output unit comprises power supply and signal processing units.

9. A system for sensing blooms as claimed in claim 8 wherein said output unit comprises:
a- Relay output ;
Open collector transistor ;
Opto coupler ;
Visual indicator ;
Volume control Buzzer ;
d- Response < 2 ms for relay and < 0.3 ms for transistor and optocoupler .
e- Remote Test facility for entire two units along with cable.

10. A system for sensing blooms in end stopper and intermediate stoppers in continuous casting in steel plant substantially as hereindescribed and illustrated with reference to the accompanying figures.

Dated this the 6th day of June, 2011
Anjan Sen
Of Anjan Sen & Associates
(Applicants Agent)