Title of Invention

" AN OPTO-ELECTRONIC SENSOR FOR MEASURING THE DEPTH OF LOOPS FORMED IN STEEL WIRE RODS DURING HOT-ROLLING THEREOF"

Abstract The invention provides an improved opto-electronic sensor for measuring the depth of loops formed in steel v/ire rods during hot rolling thereof, comprising (i) an optical viewing assembly capable of viewing the loop from a distance of 3000 nan and projecting the image of the loop in reduced size on an array of 18 infra red radiations detector diodes; (ii) a preamplifier card containing the said array of diodes, an array ox 13 preamplifiers to amplify the output -voltages. of the diodes from a few millivolts to a few volts; (iii) a signal processor card connected to the preamplifier card through a 25-pin connector, containing a threshold voltage generator to generate a threshold voltage Vx, an array of 18 voltage comparators tc compare the array of 18 preamplifier output voltages with Vx and produce an array of digital outputs comprising digital logic 1 if the preamplifier output is more than Vx and digital logic 0 if the preamplifier output is less than Vx,, buffers to produce an array of 18 buffered outputs, an array ox open collector inverters for inverting the array of buffered outputs to glow an array of 18 LEDs, another array of open collector inverters for inverting the array of 18 buffered outputs for external indication and control purposes through connectors; and (iv) an analog output card connected to the signal processor card through connector containing- decoding logics to convert the 18-bit logical signals into 11-bit lotical signals, to store the same in EPROM memory and to output 8-bit logical signals therefrom, one set of inverters connected in tandem to another set of inverters to delay the 8-bit logical signals and feed 'the delayed signals into a digital to analog converter for producing an analog output of O-10V or 0-5V.
Full Text The present invention relates to an opto-electronic sensor for measuring the depth of loops formed In Steel wire rods during hot-rolling thereof.
In the production of steel wire rods, steel billets Of typical cross section 85 x 85 mm and length 12 m are hot-rolled by a series of roller pairs arranged in tandem in a rolling mill to produce wire rods of typical diameters 5.5, 6.0, 8.0 and 10.0 mm, with formation of loops of the wire rods in the vertical and horizontal oianes at the intermediate stages of the rolling operation.
For maintaining the diameter and/or ovality of the wire rods within specified limits, it is necessary to control the depth of the loops formed at predetermined levels. In the pending Indian Patent Application No.l5l2/Cal/96 filed 25th August 1998, an automatic system for controlling the depth of vertical and horizontal loops for-med in steel wire rods curing rolling thereof has been disclosed, using the conventional type of Sensors for sensing the depth of the loops formed.
The conventional type of sensor used for sensing the depth of loops formed in wire rods during operation thereof comprises a rotating mirror to reflect the infra red radiations from the hot wire rod loops onto ar. infra red. radiations detector the electrical output of whicn is amplified to produce voltage pulses of duration proportional to tne depth of the loops using pulse shaping circuits made of transistors. The conventional type of sensor has the following drawbacks :-a) the mechanism used for rotating the mirror falls
to function too of ten;

b) the field of view of the sensor is not adequate to scan the full depth of the loops; and
c) the drift in the output voltage of the transistor-based pulse shaping circuits ts appreciable.
The object of the invention is to proviae an optoelectronic sensor for sensing the depth of wire rod loops formed during hot-rolling of wire rods in which the rotating mirror has been replaced by an optical viewing assembly having an adequately exoanded field of view and the image of the loops viewed by the assembly is projected onto an array of infra red radiation detectors to produce electrical output signals in the digital form by using IC logics to eliminate any drift of the sensor output.
The invented sensor is built in four submodules, , namely, (i) an optical viewing assembly, (ii) a pre-amplifier card, (iii) a signal processor card and (iv ) an analog output
card.
The invention is described fully and particularly without restricting its scope in any manner with reference to the accompanying drawings in which
Figure 1 is a schematic diagram showing the- connection between the submodules;
Figure 2 shows the circuit of the pre-amolifiers used one each for the array of infra red radiations detectors;
Figure 3 shows the circuit of the device for
generating a threshold voltage;
Figure 4 shows the circuit of the comparator to
convert the detector output signals into digital forms;
Figure 5 is the circuit of signal processor card; and
Figure 6 is that of analog outout card.
The optical viewing assembly comprises a lens of
diameter 63.5 mm, an aperture of width variable from 3 mm to
20 mm and a collar to prevent deposition dusts on the lens,
and is capable of viewing the hot wire rod loop from a
distance of 3000 mm, converting the wire rod loop of depth
1800 mm into an image thereof of 55 mm and projecting the
image on an array of infra red radiations detector diodes-
Referring to Figs. 1 to 5, the pre-amplifier card 1 contains an array of eighteen infra red radiation detector diodes D and an array of eighteen preamolifiers U for amplifying the electrical outout of diodes D from a few millivolts to a few volts. The circuit of a preamolier (shown in Fig. 2) comprises IC 2902 and resistor R20 (820K). The array of preamplifier output voltages is connected to the signal processor card 2 through 25-pin connector J1.
The signal orocessor card 2 contains a threshold voltage generator U6A (shown in Fig. 3) comprising IC 2902, resistor R19 (1OK ) and potentiometer PR1 (1OK) to generate a threshold voltage VX. of 3 Volt. The preamplifier output voltages are each compared with vx in an array of comparators,. The circuit each comparator (shown in Fig. 4) comprises IC 2902 and resistor Rig (1Ok)to produce digital output OP which is a digital logic 1 if the preamplifier output is more than Vx and a digital logic O if the preamplifier output is less than; Vx . The array of eighteen digital cutouts OPO-0P17 are
buffered through buffers U7, U8 and U9, each of IC 7^367 to produce an array of eighteen buffered outouts L1-L18 which are inverted through eighteen open collector inverters U10A-U10F, U11A-U11F, U12A-U12F, each of IC 7406 for glowing the array of IEDs LD1-ID18. The buffered outputs L1-L18 are separately inverted through the array of eighteen open collector inverters U13A-U13F, U14A-U14F, U15A-U15F, each of IC 7406, the inverted outputs being made available at connectors J6, J7, J8 for external indication and control purposes.
The buffered outputs L1-L18 are available also in 26-pin connector J3 (Fig. 1) which is connected to the analog output card 3 through connector 54..
The circuit of analog output card 3 (Fig. 6) contains decoding logics U1A-U1D, U2A-U2D, each of IC 7402, U3A, U3B, each of IC 7A25, U4A of IC 7400, and U8C, U8D, each of IC 7404, to convert the 18-bit logical signals L1-L18 into 11-bit logical signals for storage in EPROM memory U5 of IC 2732 having an addressing capability of 12-bit and a memory capacity of 4K bytes, and for outputting the 8-bit logical signals which are delayed through two sets of inverters, one set comprising U6A, U6C, U6E, U7A, U7C, U7E, U8A and the other set comprising U6B, U6D, U6F, U7B, U7D, U7F, U8B, each of IC 7404, connected in tandem, and fed into digital to analog converter U9 of IC AJD 558 which is capable of producing an analog output in the range ©f 0 to 10V DC, and by grounding the most significant bit an analog output of 0 to 5V only, which is buffered through U1CD of IC 2902. An offset voltage is generated by U10A of IC 2902,
which can be adjusted by potentiometer PR2 (2K) froa 0 to 5V, and added with the output of U10D in the amplifier U10B of IC 2902, the gain of which can be adjusted in the range of 1 to 2 by potentiometer PR2{2K). The added output of U10B is connected to pin 5 of connector J5 for external use. The power supplies of +5V, +12Y and -12V DC are available from connector J5 and indicated by LBl, ID2 and LD 3 respectively.
The depth of loops formed in wire rods during the hot rolling operations carried out thereon has been measured by using the invented opto-electronic sensor. The analog output voltages of the sensor obtained for loops of different depths are presented in Table 1 from which it is noted that the analog output voltage increases almost linearly from 0.24V to 2.A8V with the depth of loop increasing from 100 to 1000 mm and more rapidly from 2.48 to 5.04V with the depth of loop increasing from 1000 to 1800 mm.
The invented sensor has the following advantages over the conventional sensor :-
1. The invented sensor having no rotating component and being built entirely with solid state devices provides a better reliability of performance;
2. The invented sensor is capable of sensing the depth of all types of loops formed in the wire rods, namely, vertical, suspended, horizontal and repeater loops, by changing the lens of the optical viewing assembly of the sensor;
3. The output of the invented sensor can be interfaced with both digital and analog drive systems;
4, The programmable software used in the invented sensor allows creation of 'application specific' transfer characteris--tics of the analog output;
5. By programming the EPROM memory, the invented sensor can be used for measuring loop dimensions without changing any of its hardware components;
6. The loop indication available in the body of the invented sensor is helpful for its applications for controlllnig the wire rod rolling operations;
7. The field of view of the invented sensor is adequate for measuring the depth of all types of loops formed in wire rods; and
8. The output of the invented sensor is free from any drift.
Table 1. Depth of the Loop and Sensor Output.
(Table Removed)









We claim : -
1, An opto-electronic sensor for measuring the depth of loops formed in steel wire rods during hot rolling thereof, characterised in that the sensor comprises i.i) an optical viewing assembly containing a lens, an aperture and a collar and capable of viewing the loop from a distance of 3000 mm and projecting the image of the loop in reduced size on an array of 18 infra red radiations detector diodes D: (ii) a preamplifier card 1 containing the said array of diodes, an array of 18 preamplifiers U to amplify the output voltages of the diodes from a few millivolts to a few volts, (iii) a signal processor card 2,conneoted to the preamplifier card 1 through a 25- pin connector Jl containing a threshold voltage (Vx) generator U6A to generate threshold voltaqe (Vx), an array of 18 voltage comparators U5 to compare the array of lb preamplifier output voltages with threshold voltage (Vx) and produce an array of digital outputs OP0-OP17 comprising digital logic 1 if the preamplifier output is more than threshold voltage (Vx) and digital logic 0 if the preamplifier output is less than threshold voltage (Vx),buffers U7,U8 and U9 to product an array ot 18 buffered outputs Ll-L18,an array of open collector inverters U10A-U10F,U11A-U11F,U12A-U12F for inverting the array of Puffered outputs L1-L18 to glow an array of 18 LEDs LD1-LD18,another array of open collector inverters U13A-U13F,U14A-U14F,U15A-U15F for inverting the array of 18 buffered output L1-L18 for
'external indication and control purposes through connectors J6,J7,J8; and (iv) an analog output card 3 connected to signal processor card 2 through connector J4 containing decoding logics U1A-U1D,U2A-U2D,U3A,U3B, U4A, U8C,U8D to convert 18-bit logical signals L1-L18 into 11-bit logical signals, to store the same in EPROM memory U5 and to output 8-bit logical signals there from, one set of inverters U6A, U6C, U6E, U7A, U7E, U8A connected in tandem to another set of inverters U6B, U6D, U6F, U7B, U7D, U7D, U8B to delay the 8-bit logical signals and feed the delayed signals into a digital to analog converter U9 for producing an analog output 0-10 V or 0-5 V.
2. The sensor as claimed in claim 1, wherein the optical viewitig assembly comprises a lens of diameter 63.5mm an aperture of width variable from 3 to 2 0 mm and a collar to prevent deposition of dust on the lens, and is capable of reducing the size of the image of the loop in the ratio of 1800: 55.
3. The sensor as claimed in claim 1 or 2, wherein the threshold voltage generator is capable of generating a threshold voltage Vx of 3 volt.
4. The sensor as claimed in any preceding claim, wherein each preamplifier is built around IC 2902.
5. The sensor as claimed in any preceding claim, wherein the threshold voltage generator is built around It 2902.
6. The sensor as claimed in any preceding claim, wherein each comparator is built around IC 2902.
7. The sensor as claimed in any of preceding claim, wherein each buffer is built around IC 74 3 67.
8. The sensor as claimed in any of preceding claim wherein each open collector inverter is built around TC 7406.
9. The sensor as claimed in any of preceding claim, wherein the decoding logics UIA-UID, U2A-U2D are each built around IC 7402, USA, U3B are each built around IC 7425, U4A is built around IC 7400 and U8C. USD are each buiit around OIC 7404.
10 The sensor as claimed in any of preceding claim, wherein the sensor is provide with connector 5 to supply + 5V, +12V and 12V DC to the sensor.

Documents:

326-del-1999-abstract.pdf

326-del-1999-claims.pdf

326-del-1999-complete specification(granted).pdf

326-del-1999-correspondence-others.pdf

326-del-1999-correspondence-po.pdf

326-del-1999-description (complete).pdf

326-del-1999-drawings.pdf

326-del-1999-form-1.pdf

326-del-1999-form-19.pdf

326-del-1999-form-2.pdf

326-del-1999-form-3.pdf

326-del-1999-gpa.pdf


Patent Number 243434
Indian Patent Application Number 326/DEL/1999
PG Journal Number 43/2010
Publication Date 22-Oct-2010
Grant Date 18-Oct-2010
Date of Filing 25-Feb-1999
Name of Patentee STEEL AUTORITY OF INDIA LTD.,
Applicant Address RESEARCH & DEVELOPMENT CENTRE, IRON & STEEL,GOVT.OF INDIA ENTERPRISE, ISPAT BHAWAN,LODHI ROAD, NEW DELHI-110003,INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 SUBROTO SINHA RDCIS/SAIL,INDIA.
2 SUSHIL CHANDRA KHAN RDCIS/SAIL,INDIA.
3 GOPAL JIVAN MAHAJAN RDCIS/SAIL,INDIA.
4 SUSHIL KUMAR SABLOK RDCIS/SAIL,INDIA.
5 ASHOK KUMAR PAUL RDCIS/SAIL,INDIA.
6 SUSHANTO MAJUMDAR RDCIS/SAIL,INDIA.
7 SHANMUGAM ILANGOVAN RDCIS/SAIL,INDIA.
PCT International Classification Number H01L 27/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA