Title of Invention	"A CONTROL SYSTEM FOR AUTOMATIC PUSHING OF HOT ROLLED BARS"
Abstract	The invention provides a system for automatic control of lifting valve operation in the rolling mill of a steel plant, comprising i.  tv/o photosensors which are mounted one each at the entry point of tv/o cooling beds of the rolling mill for detecting the position of the rolled bars moving therein; two field relays, connected one each to the tv/o photosensors,  for operating the lifting valves to transfer the bars rolled in the mill to one or other of the two cooling beds; a field relay for indicating the completion of operation cycle of the lifting valves;   an opto isolator chip for converting the field inputs corresponding to the state of each of the photosensors,  contact position of the field relays used for controlling the operation of the lifting valves and contact position of the field relay used for indicating the completion of the operation cycle of the lifting valves,  into corresponding digitally isolated inputs;  a central processing unit (CPU) of a microprocessor; a TIMER; a MEMORY; a digital input interface card (PCB1);  a digital output interface card (PCB2); a display and keyboard interface card (PCB3);  a POWER SUPPLY;  and a software prepared on the basis of the algorithm,all the said components being connected to operate in an interdependent manner.

Title of Invention

"A CONTROL SYSTEM FOR AUTOMATIC PUSHING OF HOT ROLLED BARS"

Abstract

The invention provides a system for automatic control of lifting valve operation in the rolling mill of a steel plant, comprising i.  tv/o photosensors which are mounted one each at the entry point of tv/o cooling beds of the rolling mill for detecting the position of the rolled bars moving therein; two field relays, connected one each to the tv/o photosensors,  for operating the lifting valves to transfer the bars rolled in the mill to one or other of the two cooling beds; a field relay for indicating the completion of operation cycle of the lifting valves;   an opto isolator chip for converting the field inputs corresponding to the state of each of the photosensors,  contact position of the field relays used for controlling the operation of the lifting valves and contact position of the field relay used for indicating the completion of the operation cycle of the lifting valves,  into corresponding digitally isolated inputs;  a central processing unit (CPU) of a microprocessor; a TIMER; a MEMORY; a digital input interface card (PCB1);  a digital output interface card (PCB2); a display and keyboard interface card (PCB3);  a POWER SUPPLY;  and a software prepared on the basis of the algorithm,all the said components being connected to operate in an interdependent manner.

Full Text	The present invention relates to a control system for automatic pushing of hot rolled bars. In the roiling mill hot metal billets from the reheating furnace are pushed onto the roll table for being converted into rolled bars of required shapes and dimensions, and then transferred to one of two cooling beds from the delivery end of the roll table, called switch point or bifurcator. The transfer of the rolled bars from the switch point of a roll table to one of the two cooling beds is controlled by operating the lifting valves which are platforms lying between the consecutive rolls of the roll table. The lifting valves are interconnected mechanically by means of a lever by operating which the lifting valves can be raised to a level above that of the adjacent valves. All the lifting valves are disposed in a plane slanting downwardly towards the switch point of the roll table. When a lifting valve is raised by operating the lever, the movement of rolled bars towards the switch point is decelerated. But because of the disposition of the lifting valves in a downwardly slanting plane towards the switch point the rolled bars continue to slide down towards the switch point. When a rolled bar lies at the switch point or bifurcator the lifting valve there is raised by operating the lever to allow the rolled bar to slide down slowly onto the desired one of the two cooling beds. In the existing system the lifting valves are operated manually by a trained operator. But because of unavoidable errors in manual operation, the rolled bars are not always transferred to the desired cooling bed in a correct manner. For each such wrong transfer of the rolled bars to the cooling beds, an appreciable production time of 15 minutes to 1 hour is lost before the rolled bars are transferred correctly by means of cranes. The object of the present invention is to provide a microprocessor based system for automatic control of the lifting valves in substitution of the existing manual control of the lifting bars, and thus to reduce the production loss arising from the errors involved in the manual operations. The invented system comprises two photosensors mounted one each at the entry point the two cooling beds. The photosensors detect the position of rolled bars moving at the entry point of cooling beds. Since the temperature of the rolled bars at the entry point of cooling beds is around 200°C, the photosensors used are of SIRAD make. The electrical output of each photosensor is supplied to a field relay used for operating the lifting valves to transfer the rolled bars to one or other of the two cooling beds. The invented system is based on a 8085 type microprocessor and a number of printed circuit boards (PCBS) or cards, containing different functional units, such as, central processing unit (CPU), Memory, Timer, Digital Input and Digital Output, all being housed in a rack provided with a back plane connection of STD bus. The microprocessor is supplied with power from a 5V DC source. The system is provided with field inputs corresponding to : (i) the state of the photosensors; (ii) the contact position of the field relays used for controlling the operation of the lifting valves for transferring the rolled bars to either one of the two cooling beds; (iii) the contact position of the field relay used for indicating the completion of the operation cycle of the lifting valves. The data generated from the field inputs relate to the time lapsed between the activation of each photosensor and the closing of contact of the corresponding field relay for controlling the operation of the lifting valves. The field inputs are logged at a cycle time of 20 ms and the data generated are logged at the end of a operation cycle for transferring each rolled bar from the roll table to a cooling bed. The field inputs and the generated data are logged during the manual operation of the system for transferring the rolled bars to both the cooling beds. During the operation of the invented system, only the field inputs are logged. The field inputs are converted into digitally isolated inputs by using a MCT2E type opto isolator chip. For this purpose the field inputs are supplied to the opto isolator chip through the potential-free contacts of the field relays and the outputs are obtained through the potential-free contacts of the output relays. The voltage applied for the potential-free contacts of the relays is 48V. An algorithm has been developed based on which a software has been prepared for the invented system to control the operation of the lifting valves automatically. The invented system is described fully and particularly in an unrestricted manner with reference to the accompanying drawings in which - Figure 1 is a schematic layout of the central processing unit of the micro pro cessgrand associated components used in the system; and Figure 2 is an algorithm developed for preparing the software used in the system to control the operation of the lifting valves automatically. Referring to Fig. 1, CHU is the central processor unit of the 8085 type microprocessor used. TIMER is a 8253 based counter. MEMORY is of 2764 (8K ROM) and 6264 (8K RAM) type. PCB1 is a digital input interface card. PCB2 is a digital output interface card. PCB3 is a display and keyboard interface card. POWER SUPPLY is a 5V DC source. Fig. 2 is the algorithm developed for preparing the software for the operation of the system to control the lifting valves automatically. It is a flow chart based on which the software used in the system has been prepared. The various steps followed for the operation of the system have been presented in the in the symbols and notations, commonly used for programming computers. In programming, the invented system is allowed to log the field innuts initially during the period of manual control of the lifting valves as followed in the existing system. The data logged during this initial period are used as reference data for the subsequent automatic functioning of the invented system in controlling the lifting valves. The invented system has been operated under industrial conditions in the rolling mill of a steel plant. The production efficiency of rolled TMT bars has been found to increase upto 95% by using the invented system in comparison with only 25% obtained in the existing system involving manual control of the lifting valves. We Claim: 1. A control system for automatic pushing of hot rolled bars characterized in that the system comprises; two photosensors which are mounted one each at the entry point of two cooling beds of the rolling mill for detecting the position of the rolled bars moving therein; two field relays, connected one each to the two photosensors, for operating the lifting valves to transfer the bars rolled in the mill to one or other of the two cooling beds; a field relay for indicating the completion of operation cycle of the lifting valves; an opto isolator chip for converting the field inputs corresponding to the state of each of the photosensors, contact position of the field relays used for controlling the operation of the lifting valves and contact position of the field relay used for indicating the completion of the operation cycle of the lifting valves, into corresponding digitally isolated inputs; a central processing unit (CPU) of a microprocessor; a TIMER; a MEMORY; a digital input interface card (PCB1); a digital output interface card (PCB2); a display and keyboard interface card (PCB3); a POWER SUPPLY; and a software prepared on the basis of the algorithm, such as herein presented, all the said components being connected to operate in an interdependent manner. 2. The system as claimed in any preceding claim, wherein the POWER SUPPLY is a 5V DC source.

Full Text

The present invention relates to a control system for automatic pushing of
hot rolled bars.
In the roiling mill hot metal billets from the reheating furnace are pushed onto the roll table for being converted into rolled bars of required shapes and dimensions, and then transferred to one of two cooling beds from the delivery end of the roll table, called switch point or bifurcator.

The transfer of the rolled bars from the switch point of a roll table to one of the two cooling beds is controlled by operating the lifting valves which are platforms lying between the consecutive rolls of the roll table. The lifting valves are interconnected mechanically by means of a lever by operating which the lifting valves can be raised to a level above that of the adjacent valves. All the lifting valves are disposed in a plane slanting downwardly towards the switch point of the roll table. When a lifting valve is raised by operating the lever, the movement of rolled bars towards the switch point is decelerated. But because of the disposition of the lifting valves in a downwardly slanting plane towards the switch point the rolled bars continue to slide down towards the switch point.
When a rolled bar lies at the switch point or bifurcator the lifting valve there is raised by operating the lever to allow the rolled bar to slide down slowly onto the desired one of the two cooling beds.

In the existing system the lifting valves are operated manually by a trained operator. But because of unavoidable errors in manual operation, the rolled bars are not always transferred to the desired cooling bed in a correct manner. For each such wrong transfer of the rolled bars to the cooling beds, an appreciable production time of 15 minutes to 1 hour is lost before the rolled bars are transferred correctly by means of cranes.
The object of the present invention is to provide a microprocessor based system for automatic control of the lifting valves in substitution of the existing manual control of the lifting bars, and thus to reduce the production loss arising from the errors involved in the manual operations.
The invented system comprises two photosensors mounted one each at the entry point the two cooling beds. The photosensors detect the position of rolled bars moving at the entry point of cooling beds. Since the temperature of the rolled bars at the entry point of cooling beds is around 200°C, the photosensors used are of SIRAD make. The electrical output of each photosensor is supplied to a field relay used for operating the lifting valves to transfer the rolled bars to one or other of the two cooling beds.
The invented system is based on a 8085 type microprocessor and a number of printed circuit boards (PCBS) or cards, containing different functional units, such as, central processing unit (CPU), Memory, Timer, Digital Input and Digital Output, all being housed in a rack provided with a back plane connection of STD bus. The microprocessor is supplied with power from a 5V DC source.

The system is provided with field inputs corresponding to :
(i) the state of the photosensors; (ii) the contact position of the field relays used for
controlling the operation of the lifting valves for transferring the rolled bars to either one of the two cooling beds;
(iii) the contact position of the field relay used for indicating the completion of the operation cycle of the lifting valves.
The data generated from the field inputs relate to the time lapsed between the activation of each photosensor and the closing of contact of the corresponding field relay for controlling the operation of the lifting valves.
The field inputs are logged at a cycle time of 20 ms and the data generated are logged at the end of a operation cycle for transferring each rolled bar from the roll table to a cooling bed.
The field inputs and the generated data are logged during the manual operation of the system for transferring the rolled bars to both the cooling beds.
During the operation of the invented system, only the field inputs are logged. The field inputs are converted into digitally isolated inputs by using a MCT2E type opto isolator chip. For this purpose the field inputs are supplied to the opto isolator chip through the potential-free contacts

of the field relays and the outputs are obtained through the potential-free contacts of the output relays. The voltage applied for the potential-free contacts of the relays is 48V.
An algorithm has been developed based on which a software has been prepared for the invented system to control the operation of the lifting valves automatically.
The invented system is described fully and particularly in an unrestricted manner with reference to the accompanying drawings in which -
Figure 1 is a schematic layout of the central processing unit of the micro pro cessgrand associated components used in the system; and
Figure 2 is an algorithm developed for preparing the software used in the system to control the operation of the lifting valves automatically.
Referring to Fig. 1, CHU is the central processor unit of the 8085 type microprocessor used. TIMER is a 8253 based counter. MEMORY is of 2764 (8K ROM) and 6264 (8K RAM) type. PCB1 is a digital input interface card. PCB2 is a digital output interface card. PCB3 is a display and keyboard interface
card. POWER SUPPLY is a 5V DC source.
Fig. 2 is the algorithm developed for preparing the software for
the operation of the system to control the lifting valves automatically.
It is a flow chart based on which the software used in the system has been prepared. The various steps followed for the operation of the system have been presented in the

in the symbols and notations, commonly used for programming computers.
In programming, the invented system is allowed to log the field innuts initially during the period of manual control of the lifting valves as followed in the existing system. The data logged during this initial period are used as reference data for the subsequent automatic functioning of the invented system in controlling the lifting valves.
The invented system has been operated under industrial conditions in the rolling mill of a steel plant.
The production efficiency of rolled TMT bars has been found to increase upto 95% by using the invented system in comparison with only 25% obtained in the existing system involving manual control of the lifting valves.

We Claim:
1. A control system for automatic pushing of hot rolled bars characterized in that
the system comprises; two photosensors which are mounted one each at the
entry point of two cooling beds of the rolling mill for detecting the position of the
rolled bars moving therein; two field relays, connected one each to the two
photosensors, for operating the lifting valves to transfer the bars rolled in the mill
to one or other of the two cooling beds; a field relay for indicating the
completion of operation cycle of the lifting valves; an opto isolator chip for
converting the field inputs corresponding to the state of each of the
photosensors, contact position of the field relays used for controlling the
operation of the lifting valves and contact position of the field relay used for
indicating the completion of the operation cycle of the lifting valves, into
corresponding digitally isolated inputs; a central processing unit (CPU) of a
microprocessor; a TIMER; a MEMORY; a digital input interface card (PCB1); a
digital output interface card (PCB2); a display and keyboard interface card
(PCB3); a POWER SUPPLY; and a software prepared on the basis of the
algorithm, such as herein presented, all the said components being connected to
operate in an interdependent manner.
2. The system as claimed in any preceding claim, wherein the POWER SUPPLY is a
5V DC source.

Documents:

« Previous Patent

Next Patent »

Patent Number

214788

Indian Patent Application Number

2171/DEL/1997

PG Journal Number

09/2008

Publication Date

29-Feb-2008

Grant Date

15-Feb-2008

Date of Filing

05-Aug-1997

Name of Patentee

STEEL AUTHORITY OF INDIA LIMITED

Applicant Address

ISPAT BHAVAN, LODHI ROAD, NEW DELHI-110003

Inventors:

#	Inventor's Name	Inventor's Address
1	S. S. VERMA	BHILAI STEEL PLANT, SAIL, BHILAI, M.P.
2	S. K. JAIN	BHILAI STEEL PLANT, SAIL, BHILAI, M.P.
3	DEVULAPALLI SURYANARAYANA MURTY	RDCIS, SAIL, RANCHI, BIHAR;
4	NIRBHAY NEOGI	RDCIS, SAIL, RANCHI, BIHAR;
5	BINOD KUMAR PRASAD	RDCIS, SAIL, RANCHI, BIHAR;
6	SUSHIL KUMAR SABLOK	RDCIS, SAIL, RANCHI, BIHAR;
7	SUSHIL CHANDRA KHAN	RDCIS, SAIL, RANCHI, BIHAR;

PCT International Classification Number

B21B 45/02

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA