Claims:We Claim:
1.A non-contact automatized system for reliable length measurement and related operative accuracy in plate mills, continuous casters and pipe plants and the like comprising:
atleast a pair of Laser Doppler Velocimeter(LDV) equipment supported with respect to mounting arrangement above roller tables, said Laser Doppler Velocimeter(LDV) equipment spaced with respect to said roller table maintaining desired standoff distance;
said Laser Doppler Velocimeter(LDV) equipment operatively connected to transmit pulses corresponding to the desired length measurement to a PLC unit including Pulse counter module
signal convertor means including any bus Profibus convertor providing for pulse data transfer with accuracy and desired reliability for length measurement and related operative actions.
2.The non-contact automatized system for reliable length measurement and related operative accuracy as claimed in claim 1 wherein said mounting arrangement comprises adjustable mountable plate with vibration pad to minimize the vibration adapted for desired maintaining of standoffdistance;
each said Laser Doppler Velocimeter(LDV) equipment configurable for length signal in the form of quadrature pulse and profibus at the output;
signal convertor means including RS 422 convertor to Profibus and cooperative signal cables between said Laser Doppler Velocimeter(LDV) equipment and PLC.
3. The non-contact automatized system for reliable length measurement and related operative accuracy as claimed in anyone of claims 1 or 2 comprising
PLC, DCS & HMI Screens and integrated automation system to cut plates as per the desired length.
4. The non-contact automatized system for reliable length measurement and related operative accuracy as claimed in anyone of claims 1 to 3 including tuning and calibration means to obtain the desired measurement accuracy.
5. The non-contact automatized system for reliable length measurement and related operative accuracy as claimed in anyone of claims 1 to 4 wherein said Laser Doppler Velocimeter specification is selected, based on dimensions of the plate to be measured, line speed, ambient temperature etc.
6. The non-contact automatized system for reliable length measurement and related operative accuracy as claimed in anyone of claims 1 to 5 enable no-contact and reliable plate measurement during plate cutting to the desired length, which leads to 90% reduction in short length plates generation and accuracy in the final daughter plates.

Dated this the 17th day of March, 2022
Anjan Sen
Of Anjan Sen & Associates
(Applicant’s Agent)
IN/PA-199
, Description:FORM 2
THE PATENT ACT 1970
(39 OF 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

1 TITLE OF THE INVENTION :
A NON-CONTACT AUTOMATIZED SYSTEM FOR RELIABLE LENGTH MEASUREMENT AND RELATED OPERATIVE ACCURACY IN DIVIDING SHEAR OF PLATE MILLS.



2 APPLICANT (S)

Name : STEEL AUTHORITY OF INDIA LIMITED.

Nationality : Indian.

Address : Research & Development Centre for Iron & Steel,
Doranda, Ranchi, Jharkhand, India. PIN-834002.






3 PREAMBLE TO THE DESCRIPTION

COMPLETE

The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
Present invention relates to a system for non-contact plate length measurement at Plate Mill with enhanced accuracy. More particularly, the present invention is directed to an automatized system involving laser Doppler based non-contact type plate length measurement wherein two sets of Laser Doppler Velocimeter equipment with appropriate technical specification are installed on specially designed platform above roller table in dividing shear of Plate mill such that the stand-off distance requirement is maintained and Signal from LDVs are interfaced with the existing PLC in Profibus as well as quadrature pulse forms. Necessary modifications were done in the PLC and DCS system. This system helps in reliability of plate measurement during plate cutting to the desired length, which leads to 90% reduction in short length plates generation and accuracy in the final daughter plates.

BACKGROUND OF THE INVENTION
New plate mill of Applicant’s Rourkella Steel Plant(RSP) was facing anissue to accurately measure the length of daughter plates due to unreliable length measurement and automation system. Dividing shear is used to cut daughter plates from the mother plate according to requirements from the end users. Length measurement system provided originally during Commissioning was based on measuring wheel and encoder arrangement, where the measuring wheel touches the plate surface from top and is pressed pneumatically to the plate. These contact type arrangement of length measurement are less precise due to mechanical slippage and breakdown prone. Due to inaccurate length measurement, mill yield gets adversely affected. It wasthus proposed to design and implement a non-contact length measurement system so that reliability and accuracy of length measurement could be enhanced.

Contact based on measuring wheel and encoder arrangement, where the measuring wheel touches the plate surface from top and is pressed pneumatically to the plate is commonly used. These contact type arrangement of length measurement are less precise due to mechanical slippage and breakdown prone

OBJECTS OF THE INVENTION
The basic object of the present invention is directed to provide an automation system for non contact measurement of plate length for cutting at dividing shear in plate mill with improved and consistent accuracy.

A further object of the present invention is directed to said automation system wherein Laser Doppler Velocimeter based non-contactplate length measurement is introduced for improvement in reliability of plate length measurement system at Dividing shear of New Plate Mill by increase in the accuracy of cutting length.

A still further object of the present invention is directed to an automated system for plate length measurement at dividing shear of plate mill enabling 90% reduction in short length plates generation and accuracy in the final daughter plates.

A still further object of the present invention is directed to an automated system for non contact plate length measurement at dividing shear which can be applicable in other units like Continuous Caster, Pipe plant etc., wherever contact type length measurement system is being used presently.

SUMMARY OF THE INVENTION

The basic aspect of the present invention is directed to a non-contact automatized system for reliable length measurement and related operative accuracy in plate mills, continuous casters and pipe plants and the like comprising:
atleast a pair of Laser Doppler Velocimeter(LDV) equipment supported with respect to mounting arrangement above roller tables, said Laser Doppler Velocimeter(LDV) equipment spaced with respect to said roller table maintaining desired standoff distance;
said Laser Doppler Velocimeter (LDV) equipment operatively connected to transmit pulses corresponding to the desired length measurement to a PLC unit including Pulse counter module
signal convertor means including any bus Profibus convertor providing for pulse data transfer with accuracy and desired reliability for length measurement and related operative actions.
A further aspect of the present invention is directed to said non-contact automatized system for reliable length measurement and related operative accuracy wherein said mounting arrangement comprises adjustable mountable plate with vibration pad to minimize the vibration adapted for desired maintaining of standoff distance;
each said Laser Doppler Velocimeter(LDV) equipment configurable for length signal in the form of quadrature pulse and profibus at the output;
signal convertor means including RS 422 convertor to Profibus and cooperative signal cables between said Laser Doppler Velocimeter(LDV) equipment and PLC.

A still further aspect of the present invention is directed to said non-contact automatized system for reliable length measurement and related operative accuracy comprisingPLC, DCS & HMI Screens and integrated automation system to cut plates as per the desired length.

A still further aspect of the present invention is directed to said non-contact automatized system for reliable length measurement and related operative accuracy as claimed in anyone of claims 1 to 3 including tuning and calibration means to obtain the desired measurement accuracy.
Another aspect of the present invention is directed to said non-contact automatized system for reliable length measurement and related operative accuracywherein said Laser Doppler Velocimeter specification is selected, based on dimensions of the plate to be measured, line speed, ambient temperature etc.
Yet another aspect of the present invention is directed to said non-contact automatized system for reliable length measurement and related operative accuracy that enable no-contact and reliable plate measurement during plate cutting to the desired length, which leads to 90% reduction in short length plates generation and accuracy in the final daughter plates.

The above and other aspects and advantages of the present invention are described hereunder in greater details with reference to the following accompanying non limiting illustrative drawing.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Figure 1: is the schematic illustration of the system for accurate non-contact plate length measurement at dividing shear in plate mill according to present invention.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWING
The present invention is directed to provide a system for improved and reliable non-contact plate length measurement at Dividing shear of Plate Mill with increase in the accuracy of cutting length.

The new length measurement system was designed with laser doppler velocimeter to improve accuracy in non-contact plate length measurement at dividing shear of New Plate mill. Detail scheme of the system has been shown in accompanying Figure 1 wherein,
1. Laser Doppler Velocimeter was selected, based on dimensions of the plate to be measured, line speed, ambient temperature etc.
2. Mounting design was finalized based on practical requirements of the plant and technical issues.
3. Fabrication of mounting structure designed such that stand-off distance is maintained without any need to move the equipment due to change in thickness of the plates.
4. Special signal cables were laid between the LDV and existing PLC to transmit pulses corresponding to the length measurement. Pulse counter modules of the existing PLC were configured accordingly.
5. PLC program, DCS & HMI Screens has been modified using in-house expertise and integrated automation system was designed to cut the plates as per the desired length.

To increase the reliability of system laser doppler velocimeter based non-contact type measurement system was adopted. Laser doppler velocimeter were installed on specially designed platform above roller table. Signal from LDVs are interfaced with the existing PLC in Profibus as well as quadrature pulse forms. Necessary modifications were done in the PLC and DCS system.

The main components of the system include:
• Laser Surface Velocimeter LSV 2100
• Any Bus Profibus Converter
• ABB PLC

LSV2100 actually senses the movement of plate and measures the length of the plate travelled. Anybus converter is used to covert data from RS422 to Profibus for better transfer of data. In ABB PLC, the data from profibus is collected and programmed in a way that plate will be stopped at given set length for shearing purpose.

Length of the plate can be transferred through pulse counts generated by LSV2100 accordingly programme is modified to know the exact length of plate without converting data using any bus which is also carried out by the system. Speed of plate should be in the range of 0 to ±7000m/min for detection by bidirectional sensor.

The automation system for plate length measurement was successfully designed, installed and commissioned in diving shear of New Plate mill. This system helps in reliability of plate measurement during plate cutting to the desired length, which leads to 90% reduction in generation of short length plates and improved consistent accuracy in the final daughter plates.

Advantages of the Invention:
The new plate length measurement system with Laser doppler velocimeter was installed in Dividing shear of New Plate mill. Following benefits were achieved.
i. Reduction in short plate generation.
ii. Increase in the accuracy of the plate length measurement.
iii. With increase in reliability of plate lengths yield also increased.
This innovation can be used in all Mills of the applicant and casters where cutting and length measurements are being done with contact type measurement systems for improvement in accuracy and yield also.
Industrial Applicability:
The innovation can be used in other units like Continuous Caster, Pipe plant etc., wherever contact type length measurement system is being used presently. The favorableoutcome of the innovation is tested and can be horizontally transferred to all other units of steel plants.