CLIAMS:We Claim:

1. A system for steel making involving a working lance and avoiding lance overheating and consequential delay in steel making comprising:
atleast one working lance adapted to withstand high temperature during steel making comprising water circulating circuit for demineralized water in and out of the lance ;
hot water coming out of the lance being cooled through heat exchanger means and recirculated to inlet of said lance ;
a make up tank filled with demineralised water operatively connected to said water circulating system;
means for continuously monitoring the level of demineralized water in said make-up tank supplying demineralised water to said working lance and ensuring content of demineralized water therein such as to ensure continuous uninterrupted supply of demineralised water to said working lance and thereby avoiding lance overheating and consequential delay in steel making.

2. A system as claimed in claim 1 wherein said means for continuous monitoring the level of demineralized water in said make-up tank supplying demineralised water to said working lance and ensuring content of demineralized water therein comprises a counter weight type float switch fixed on top inspection hole of said tank, a float ball attached to a rope means adapted to float on the water in said tank with the other end of the rope being attached to the lever of said switch such that when the level of water in the tank is below desired level the same activates the switch for filling of the tank.

3. A system as claimed in anyone of claims 1 or 2 wherein said float ball is a rubber float ball and said rope is a nylon rope.

4. A system as claimed in anyone of claims 1 to 3 comprising alarm means for activating an alarm when the level of water in the tank is below desired level comprising a buzzer and/or an indicating lamp in control room to ensure said fill up the storage tank in due time to continue uninterrupted flow of DM water in lance cooling circuit.

5. A system as claimed in anyone of claims 1 to 4 wherein the length of said rope is adjusted as per alarm level of the tank.

6. A system as claimed in anyone of claims 1 to 5 wherein said switch arrangement is preferably shielded with a PVC cover.

Dated this the 18th day of June, 2014
Anjan Sen
Of Anjan Sen & Associates
(Applicants Agent)

,TagSPECI:FIELD OF THE INVENTION

The present invention relates to a system for steel making involving a working lance and avoiding lance overheating wherein a low water level alarm system for demineralised water storage Tank of Lance Cooling system in LD converter is used. More particularly, the present invention is directed to a Counter Weight Type Float Switch based alarm generation system installed on inspection cover of internally rubber coated demineralised water storage tank of Lance Cooling System of LD converter adapted to generate alarm for the operator to detect Low Water Level in Tank and ensure continuous cooling water supply for lance cooling avoiding interruption in steel production.

BACKGROUND OF THE INVENTION

In Basic Oxygen Furnace, steel is prepared by treating liquid iron with stream of oxygen. Liquid iron is poured into a vessel called LD converter. A lance is lowered axially into the vessel and oxygen is blown @10 kg/cm2. Exothermic reaction takes place and the temperature inside vessel rises up to 1200 o C. Lance pipe should withstand this high temperature during steel making. To control the temperature rise of lance, de-mineralized water is circulated in and out of lance continuously by pumps.

The hot water coming out of lance is cooled through plate heat exchanger and returns to inlet pipe of the pumps. A makeup tank full of de-mineralized water remains connected to the water circulating circuit. Due to vaporization and minor leakage during lance replacement, water loss occurs in the circuit. It is compensated by the water of lance makeup tank. A level transmitter is fixed on the tank. It continuously sends signal regarding level to the process computer. Maintaining required level in the makeup tank is a vital interlock for steel making.

River water is treated in degasser, cation filter and anion filter for removal of minerals and the de-mineralized (DM) water is stored in a closed tank. This process takes about 3 hours . There is no level transmitter connected on this storage tank.

The fall in level of makeup tank is normalized by transferring water from storage tank. By repeated out take of water from storage tank caused emptying of tank and operator could not know the exact level of tank as no level measuring system is fitted on the storage tank. This lacuna in the system caused stoppage of required water flow in lance and a delay in carrying out steel making.

There has been thus a persistent need in the field of lance cooling in steel making to ensure continuous supply of demineralized water for lance cooling by incorporating appropriate level measuring system on storage tank to sense the alarming low level and alert the operator to take prompt action in filling the storage tank, so that fall in level of makeup tank is reliably compensated by transferring water from storage tank avoiding interruption in steel production.

OBJECTS OF THE INVENTION

The basic object of the present invention is thus directed to a system for steel making involving a working lance and avoiding lance overheating involving a low water level alarm system for demineralised water storage Tank of Lance Cooling system in LD converter.

A further object of the present invention is directed to provide a system for steel making involving a working lance and avoiding lance overheating involving a low water level alarm system for demineralised water storage Tank of Lance Cooling system wherein a water level sensing system on storage tank is installed to sense the alarming low level and alert the operator to take prompt action in filling the storage tank, so that fall in level of makeup tank is reliably compensated by transferring water from storage tank.

A still further object of the present invention is directed to provide a system for steel making involving a working lance and avoiding lance overheating involving a Counter Weight Type Float Switch based alarm generation system installed on inspection cover of internally rubber coated demineralised water storage tank of Lance Cooling System of LD converter to sense alarmingly low water level in storage tank and activate a buzzar to alert the operator to immediately operate the pump to fill water.

A still further object of the present invention is directed to provide a system for steel making involving a working lance and avoiding lance overheating involving a low water level alarm system for demineralised water storage Tank of Lance Cooling system whereby fall in level of makeup tank will be normalized by transferring water from storage tank in a reliable manner for demineralised water storage Tank of Lance Cooling system in LD converter

A still further object of the present invention is directed to provide a system for steel making involving a working lance and avoiding lance overheating involving a low water level alarm system for demineralised water storage Tank of Lance Cooling system which would favour avoiding stoppage of required water flow in lance and consequent delay in carrying out steel making.

SUMMARY OF THE INVENTION

The basic aspect of the present invention is thus directed to a system for steel making involving a working lance and avoiding lance overheating and consequential delay in steel making comprising:
atleast one working lance adapted to withstand high temperature during steel making comprising water circulating circuit for demineralized water in and out of the lance ;
hot water coming out of the lance being cooled through heat exchanger means and recirculated to inlet of said lance ;
a make up tank filled with demineralised water operatively connected to said water circulating system;
means for continuously monitoring the level of demineralized water in said make-up tank supplying demineralised water to said working lance and ensuring content of demineralized water therein such as to ensure continuous uninterrupted supply of demineralised water to said working lance and thereby avoiding lance overheating and consequential delay in steel making.

A further aspect of the present invention is directed to said system wherein said means for continuous monitoring the level of demineralized water in said make-up tank supplying demineralised water to said working lance and ensuring content of demineralized water therein comprises a counter weight type float switch fixed on top inspection hole of said tank, a float ball attached to a rope means adapted to float on the water in said tank with the other end of the rope being attached to the lever of said switch such that when the level of water in the tank is below desired level the same activates the switch for filling of the tank.

A still further aspect of the present invention is directed to said system wherein said float ball is a rubber float ball and said rope is a nylon rope.

Yet another aspect of the present invention is directed to said system comprising alarm means for activating an alarm when the level of water in the tank is below desired level comprising a buzzer and/or an indicating lamp in control room to ensure said fill up the storage tank in due time to continue uninterrupted flow of DM water in lance cooling circuit.

A further aspect of the present invention is directed to said system wherein the length of said rope is adjusted as per alarm level of the tank.

A still further aspect of the present invention is directed to said system wherein said switch arrangement is preferably shielded with a PVC cover.

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

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1: shows a schematic view of conventional arrangement of the disposition of oxygen blowing lance in steel making converter and the cooling water circulation system for lance cooling.

Figure 2: shows the schematic view of conventional lance cooling water circulation system involving demineralised water preparation pump house, lance cooling water makup tank, dimineralized water storage tank(not shown) supplying to make up tank and the connecting pipelines and valves.

Figure 3: show the schematic view of the DM water storage tank wherein the Counter Weight Type Float Switch based alarm generation system according to the present invention has been installed on inspection cover of internally rubber coated demineralised water storage tank.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

The present invention is directed to a system for steel making involving a working lance and avoiding lance overheating and consequential delay in steel making wherein a Counter Weight Type Float Switch based alarm generation system has been advantageously installed on inspection cover of internally rubber coated demineralised water storage tank of Lance Cooling System of LD converter adapted to uninterrupted supply of demineralised water to make up tank to compensate fall in water level.

Accompanying Figure 1 shows a schematic view of conventional arrangement of the disposition of oxygen blowing lance in steel making converter and the cooling water circulation system for lance cooling. De-mineralized water is circulated in and out of lance continuously by pumps.

Accompanying Figure 2 shows the schematic view of conventional lance cooling water circulation system involving demineralised water preparation pump house, lance cooling water makup tank, dimineralized water storage tank(not shown) supplying to make up tank and the connecting pipelines and valves. The hot water coming out of lance is cooled through plate heat exchanger and returns to inlet pipe of the pumps. A makeup tank full of de-mineralized water remains connected to the water circulating circuit. Due to vaporization and minor leakage during lance replacement, water loss occurs in the circuit. It is compensated by the water of lance makeup tank. A level transmitter is fixed on the tank. It continuously sends signal regarding level to the process computer. Maintaining required level in the makeup tank is a vital interlock for steel making. River water is treated in degasser, cation filter and anion filter for removal of minerals and the de-mineralized (DM) water is stored in a closed tank. This process takes about 3 hours. There is no level transmitter connected on this storage tank. The fall in level of makeup tank is normalized by transferring water from storage tank. By repeated out take of water from storage tank caused emptying of tank and operator could not know the exact level of tank as no level measuring system is fitted on the tank.

To overcome the above stated limitation and disadvantage of the existing lance cooling system in LD Converter, a Counter Weight Type Float Switch based alarm generation system has thus been developed and installed on inspection cover of internally rubber coated demineralised water storage tank by way of the present invention for detection of alarming low water level in storage tank and alert the operator.

Accompanying Figure 3 shows the schematic view of the DM water storage tank wherein the Counter Weight Type Float Switch based alarm generation system according to the present invention has been installed on inspection cover of internally rubber coated demineralised water storage tank. As the inside of the storage tank is coated with rubber, cutting and welding job on its body are strictly prohibited. Thus for detection of water level, a simple counter weight type float switch was fixed on cover of top inspection hole. A rubber float ball attached to a nylon rope was dropped through a small hole made on the cover. The other end of rope is attached to the lever of the switch. The length of rope is adjusted as per alarm level of the tank. When water level falls below alarm level the float ball goes down along with the water level. The rope pulls the arm of the counter weight switch and the switch becomes “ON”. It activates a buzzer in the control room to alert the operator to fill up the storage tank in due time to continue uninterrupted flow of DM water in lance cooling circuit. Implementation of this level detection and alarm generation system in DM water storage tank helps compensating the fall in level of makeup tank by transferring water from storage tank in a reliable manner and thus achieving enhanced rate of production in steel making avoiding interruptions.
It is thus possible by way of the present invention to provide counter weight type float switch on inspection cover of internally rubber coated demineralised water storage tank of lance cooling system for alarming low water level in tank to ensure uninterrupted supply of cooling water for lance cooling and thus enhance production by avoiding interruption of operation in LD Converter.

We Claim:

1. A system for steel making involving a working lance and avoiding lance overheating and consequential delay in steel making comprising:
atleast one working lance adapted to withstand high temperature during steel making comprising water circulating circuit for demineralized water in and out of the lance ;
hot water coming out of the lance being cooled through heat exchanger means and recirculated to inlet of said lance ;
a make up tank filled with demineralised water operatively connected to said water circulating system;
means for continuously monitoring the level of demineralized water in said make-up tank supplying demineralised water to said working lance and ensuring content of demineralized water therein such as to ensure continuous uninterrupted supply of demineralised water to said working lance and thereby avoiding lance overheating and consequential delay in steel making.

2. A system as claimed in claim 1 wherein said means for continuous monitoring the level of demineralized water in said make-up tank supplying demineralised water to said working lance and ensuring content of demineralized water therein comprises a counter weight type float switch fixed on top inspection hole of said tank, a float ball attached to a rope means adapted to float on the water in said tank with the other end of the rope being attached to the lever of said switch such that when the level of water in the tank is below desired level the same activates the switch for filling of the tank.

3. A system as claimed in anyone of claims 1 or 2 wherein said float ball is a rubber float ball and said rope is a nylon rope.

4. A system as claimed in anyone of claims 1 to 3 comprising alarm means for activating an alarm when the level of water in the tank is below desired level comprising a buzzer and/or an indicating lamp in control room to ensure said fill up the storage tank in due time to continue uninterrupted flow of DM water in lance cooling circuit.

5. A system as claimed in anyone of claims 1 to 4 wherein the length of said rope is adjusted as per alarm level of the tank.

6. A system as claimed in anyone of claims 1 to 5 wherein said switch arrangement is preferably shielded with a PVC cover.

Dated this the 18th day of June, 2014
Anjan Sen
Of Anjan Sen & Associates
(Applicants Agent)

ABSTRACT

TITLE: A SYSTEM FOR STEEL MAKING INVOLVING A WORKING LANCE AND AVOIDING LANCE OVERHEATING AND CONSEQUENTIAL DELAY IN STEEL MAKING.

A system for steel making involving a working lance and avoiding lance overheating is disclosed wherein a low water level alarm system for demineralised water storage Tank of Lance Cooling system in LD converter has been used advantageously to avoid consequential delay in steel making due to lance overheating for stoppage in cooling water supply. More particularly, the present invention is directed to a Counter Weight Type Float Switch based alarm generation system installed on inspection cover of internally rubber coated demineralised water storage tank of Lance Cooling System of LD converter adapted to generate alarm for the operator to detect Low Water Level in Tank and ensure continuous cooling water supply for lance cooling avoiding interruption in steel production.
(Figure 1)