Title of Invention

AN ELECTRONIC INSTRUMENT FOR DETECTING THE PASSAGE OF WELDED JOINTS IN STEEL SHEETS DRAWN THROUGH THE NIP OF LEVELLER ROLLS

Abstract

An electronic instrument for detecting the passage of welded joints in sheet coils of steel, drawn continuously through the nip of leveller rolls, and for increasing the gap at the nip by operating a device provided for the purpose to prevent breakage of the joints, comprising combination of a source of light energy, a detector of light energy and an electronic amplifier with an associated light emitting diode and a relay. The source of light energy is an array of tungsten filament lamps of 100 W, 230 V rating housed in a casing of U-shaped cross section, mounted underneath the surface of the sheet coils. The detector of light energy is an array of photo-diodes, connected in parallel and housed in a casing of rectangular cross section, mounted above the surface of sheet coils. The electronic amplifier comprises a number of high-gain, internally frequency-compensated operational amplifiers, connected in tandem.

Full Text

The present invention relates to an electronic instrument for detecting the passage of welded joints in steel sheets drawn through the nip of leveller rolls. In carrying out continuous processing operations on sheet coils of steel, such as pickling, annealing, cleaning, and galvanising, the tailing end of a processed sheet coil is jointed to the leading end of an unprocessed sheet coil by welding. The welded joints thus formed are relatively weak regions which are liable to be broken while the sheet coils are drawn through the nip of the leveller rolls, causing interruption in the process with resultant loss of production. In order to prevent breakage at the welded joints, it is necessary to detect their arrival near the nip of the rolls and to increase the gap between the rolls for allowing the joints to pass through without being broken. In the existing art, no suitable means is available to meet this requirement, as a result of which there is an appreciable loss of production. The object of the invention is to provide an electronic instrument for detecting the arrival of the joints near the nip of leveller rolls and increasing the gap between rolls for allowing the joints to pass through" without being broken. The other object is to prevent loss of production caused by breakage of the coils at the welded joints therein. The invented instrument comprises basically (i) a source of light disposed underneath the continuously moving sheet coils at a location some distance away from the nip of leveller rolls - 2 - towards the approaching joints; (ii) a detector of light energy disposed above the coils, being aligned with the source of light in a vertical plane passing across flat surface of the coils lying in a horizontal plane; (iii) an electronic amplifier for amplifying the electrical signal produced by the detector of light energy when the light rays from the source of light passes through a hole made near each welded Joint in the coil and strike the detector, and applies the amplified output signal to actuate a LSD for indicating the passage of the Joints through the nip of the leveller rolls and to energise a relay for operating a mechanism which increases the gap between the rolls and allows the passage of the joints without being broken. The invention is described fully and particularly in an unrestricted manner with reference to the accompanying drawings, in which - Figure 1 is a schematic lay-out of the main components of the instrument; and Figure 2 is the circuit diagram of the electronic amplifier and the associated LED and Relay, Referring to Pig. 1, the source (1) of light energy, contains five tungsten filament lamps each of rating 100W, 230V, arranged in an array housed in a casing of U-shaped cross section, and of length 300 mm, height 180 mm and width 130 mm. The detector (2) of light energy contains an array of five photo-diodes of MOP type connected electrically in parallel and housed in a casing of rectangular cross section, and length 380 mm, height -85 ma and width 105 mm. Sheet coils (4) containing welded Joints - 3 - (5) and holes (6) near each welded joint are drawn through the space between light source (1) and light detector (2), of which the former is disposed underneath and the latter above the horizontal flat surface of the coils, their positions being aligned with respect to each other. The signal voltage generated in the light detector (2), when the light rays (7) pass through hole (6) and fall on the array of photo-diodes mounted inside the light detector (2), is supplied at the input (IN) of the electronic amplifier (3) for actuating a LED indication and a relay which are housed therein. Referring to Fig. 2, the circuit of the electronic amplifier comprises four high-gain, internally-frequency- compensated operational amplifiers of integrated circuits (ICs) U1A, U1B, U1C and U1D, each of type LM324, as available in a LM 2902N quad operational amplifier. The signal voltage from the output of light detector (2) is supplied at the input (IN), which is amplified by ICs U1C, U1B, U1A and U1D connected in tandem. The output (OUT) voltage obtained at terminal 14 of 1C U1D is amplified by transistor T3 to actuate the light emitting diode, (LED3) connected at the collector thereof. The output of T3 as available across resistor R27 is further amplified by transistor T1 and the amplified current flowing through the collector thereof energises relay (RL1) which, in turn, actuates the contactor (D) connected across the contact terminals (C) and (NO) of the relay. The contactor (D) thus energised actuates a mechanism (not shown) which increases the gap at the nip of leveller rolls (not shown). - 4 - The relay (RL1) Is of 150 ohm coil resistance and operable from a 12V DC supply. The power supply (VCC) is of regulated 12V DC, 1A and obtained from 230V AC mains. Transistor (T2) provides an open output for actuating a control device (E). The particulars of the components used in Fig. 2 are given in Table I. The invented instrument has "been installed in the 'hot dip' galvanising line of a steel plant. The breakages at, the welded joints of sheet coils without using the instrument have been found to be reduced significantly by using the instrument, leading to an increase in the productivity and consequent economic gain which is estimated to be Rupees Ten Lakhs annually. TABLE - 1 PARTICULARS OF THE COMPONENTS USED IN FIG.2 SL NO. SYMBOL DESCRIPTION QTY 1. UIA-D LM324 1 2. T2,T3 Transistor 2N2222A 2 3. T4 Transistor 2N6107 1 4. D9 Diode 1N4007 1 5. D6-D8 Diode 1N4148 3 6. P1-P3 Pot, 503, TRIMPOT-USA(50K) 3 7. LED3 Light Emitting diode, 5mm 1 8. C4 Disc Cap 104 1 9. C5 Electrolytic-Cap. 47uf/100V 1 10. R6,R11,R12,R16,R19 ,R20,R25,R26 CFR, 1/2W, 1 K 8 11. R7,R10,R13,R14,R27 CFR,1/2W, 10K 5 12. R18,R21,R22 CFR,1/2W,100K 3 13. R9,R15 CFR,1/2W,22K 2 14. R8 CFR,1/2W,47K 1 15. R23,R24 CFR,1/2W,4K7 2 16 R29 CFR,1/2W,2K2 17 R28 CFR,2W,2E2 18. R17 CFR,1/2W,100E 19. R3 CFR,3W,22E 20. RL Relay, 12V DC, 1C/O type 4R-1-12S OEN Make(50 Ohm) - 6 - We Claim :- 1. An electronic instrument for detecting the passage of welded joints in steel sheets in the form of coils drawn continuously through the nip of leveller rolls and increasing the gap at the nip to prevent breakage of the joints, characterised in that the instrument comprises a source of light energy (1), such as herein described, a detector (2) of light energy, such as herein described, and an electronic amplifier (3) with associated light emitting diode (LED3), a relay (RL1), and a contactor (D), such as herein described. 2.* The instrument as claimed in claim 1, wherein the source of light energy is an array of five tungsten filament lamps each of rating 100W, 230V, housed in a casing of U-shaped cross section and length 300 mm, height 180 mm and width 130 mm, which is mounted underneath the surface of the sheet coils. 3. The instrument as claimed in claims 1 and 2, wherein the detector of light energy is an array of five photo-diodes of NP type, connected electrically in parallel, housed in a casing of rectangular cross section, and length 380 mm, hight 85 mm and width 105 mm, which is mounted above the surface of sheet coils. 4. The instrument as claimed in claims 1 to 3, wherein the electronic amplifier comprises four high-gain, internally-frequency-compensated operational amplifiers of integrated circuits (ICs) U1A, UlB, U1C and U1D, each of LM324 type, - 7 - as available in a LM 2902 N type quad operational amplifier, connected in tandem, the input (IN) of which is connected to the output of the detector of light energy and the output (out) of which is connected to the input of transistor (T3), the output of transistor (T 3) being connected to the input of transistor (T1)• 5. The instrument as claimed in claim 4, wherein a LED5 is connected at the collector of transistor (T3) and a relay (RL1) at the collector of transistor (Tl). 6. The instrument as claimed in claims 5 and 6, wherein the relay is of coil resistance 150 ohm and operable from a 12V DC supply, 7. The instrument as claimed in any preceding claim, wherein the power supply (VCC) of the electronic amplifier is regulated 12V DC, 1A, obtained from 230V Ac mains. - 8 - Dated this 24th day of October 1997. An electronic instrument for detecting the passage of welded joints in sheet coils of steel, drawn continuously through the nip of leveller rolls, and for increasing the gap at the nip by operating a device provided for the purpose to prevent breakage of the joints, comprising combination of a source of light energy, a detector of light energy and an electronic amplifier with an associated light emitting diode and a relay. The source of light energy is an array of tungsten filament lamps of 100 W, 230 V rating housed in a casing of U-shaped cross section, mounted underneath the surface of the sheet coils. The detector of light energy is an array of photo-diodes, connected in parallel and housed in a casing of rectangular cross section, mounted above the surface of sheet coils. The electronic amplifier comprises a number of high-gain, internally frequency-compensated operational amplifiers, connected in tandem.

Documents:

02000-cal-1997-abstract.pdf

02000-cal-1997-assignment.pdf

02000-cal-1997-claims.pdf

02000-cal-1997-correspondence.pdf

02000-cal-1997-description(complete).pdf

02000-cal-1997-drawings.pdf

02000-cal-1997-form-1.pdf

02000-cal-1997-form-2.pdf

02000-cal-1997-form-3.pdf

02000-cal-1997-p.a.pdf

2000-cal-1997-granted-abstract.pdf

2000-cal-1997-granted-acceptance publication.pdf

2000-cal-1997-granted-assignment.pdf

2000-cal-1997-granted-claims.pdf

2000-cal-1997-granted-correspondence.pdf

2000-cal-1997-granted-description (complete).pdf

2000-cal-1997-granted-drawings.pdf

2000-cal-1997-granted-examination report.pdf

2000-cal-1997-granted-form 1.pdf

2000-cal-1997-granted-form 2.pdf

2000-cal-1997-granted-form 3.pdf

2000-cal-1997-granted-letter patent.pdf

2000-cal-1997-granted-pa.pdf

2000-cal-1997-granted-reply to examination report.pdf

2000-cal-1997-granted-specification.pdf