Claims:We Claim:

1. A system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant comprising:

a portable operator station;

a wireless trans-receiver station in hydraulic room;

means adapted for sensing various analog and/or digital signals;

means adapted to control mudgun and drill machine movement;

a PLC based means adapted for generating commands for mudgun and drill machine operation, process monitoring, control and alarm generation.

2. The system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant as claimed in claim 1 comprising:

said portable operator station for generating analog/digital signals in relation to controlling the mudgun and drill machine;

said wireless trans-receiver station in hydraulic room having means for sensing the analog/digital signals related to said mudgun and drill machine;

said PLC based means for controlling the mudgun and drill machine movement, operation, process monitoring, control and alarm generation.

3. The system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant as claimed in anyone of claim 1 or 2, wherein said portable operator station is battery operated and comprise Radio Modem, Joysticks with toggle switches, Display panel and Emergency switch for generating analog/digital signals in relation to controlling the mudgun and drill machine to take care of all the operations of mudgun and drill machine.

4. The system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant as claimed in any one of claims 1 to 3, wherein said wireless trans-receiver station in hydraulic room comprises Radio Modem, Relay boards, Switchgears and a omni-directional antenna mounted outside the hydraulic room for remotely communicating with the portable station at a particular frequency and receiving the signals from the portable operator station.

5. The system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant as claimed in any one of claims 1 to 4, wherein the wireless trans-receiver station is adapted to communicate the received signals to the PLC based means as digital inputs via relay boards.

6. The system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant as claimed in any one of claims 1 to 5, wherein the PLC based means includes CPU module, Digital input module, Digital output module, Analog input module, Analog output module and Communication module.

7. The system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant as claimed in any one of claims 1 to 6, wherein said PLC based means executes sequencing and interlocking sequences to generate set of controlling commands for mudgun and drill machine operations in form of potential free contacts and wired said potential free contacts to relay panel for driving hydraulically and pneumatically operated valves corresponding to the mudgun and drill machine.

8. The system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant as claimed in any one of claims 1 to 7, wherein said hydraulic valve comprises of:
I. Proportional valve
II. Hydraulic check valve
III. Pressure compensator
IV. Pressure reducing valve
V. Ball valve

9. The system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant as claimed in any one of claims 1 to 8, wherein the portable operator station is compact and handheld.

10. The system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant as claimed in any one of claims 1 to 9, wherein controlling the mudgun and drill machine by involving direct transmission of signals from the handheld portable operator station in any safe location in the blast furnace cast house reduce possibility of breakdown, thereby increasing availability of said mudgun and drill machine thereby enhancing blast furnace productivity and providing flexibility to operate cast house equipment from a safe distance.
, Description:FIELD OF THE INVENTION
The present invention relates to development of radio signal based remote controlling of blast furnace cast house equipments. More particularly, the invention is directed to design and develop a radio remote control system for mudgun and drill machine of Blast furnace cast house. The system of the invention advantageously ensures reliability of signal transmission thereby achieving reduction in downtime of equipment and enhancing reliability of the operation favoring wide scale application of such system for safe operation of equipments in hazardous locations at Steel Plants.

BACKGROUND OF THE INVENTION
In the hostile environment of steel plants, cables get burnt or cut, causing breakdowns. There are areas where cable laying is either extremely difficult or almost impossible, more so during ongoing process. Safety of operating personnel is sometimes compromised due to close proximity of potential hazards.

It is well known that, Mudgun and drill machine are most vital equipment for Blast Furnace Cast house of any steel plant. In the beginning of the process, one machine called mudgun is used to pack the tap hole with mud. Then burden is charged from the top and the process of iron making starts. Once the Furnace is ready with the iron making, drill machine is used to drill through the tap hole and the liquid iron comes out. Operation of mudgun and drill machine is realized by hydraulic / pneumatic valves. The close proximity of the control desks from the tap hole possesses threat to the operating personnel. Also, the splinters from the flowing metal cause damage to the associated cables of the control desk, which affects the taping operation, leading to reduced blast in Blast furnace.

Any breakdown in the control cable, or associated switchgear on the desk, causes loss of control on the drill machine / mudgun and eventually damages the machine resulting in loss of production.

Thus the existing control desk based control for operations of cast house equipments of a Blast Furnace suffers from the following limitations:
(i) Transmission of signals by the conventional method using fixed control desk and control cables brings in unreliability in operation.
(ii) Trouble shooting in the control desk switchgears or cables during metal tapping through tap hole was not possible
(iii) The close proximity of the control desks from the tap hole posed threat to the operating personnel
(iv) Any breakdown in the mudgun or drill machine adversely affected Blast Furnace operation

Now with the recent development in wireless technology, it became a potential candidate for implement in the steel plant for remotely controlling the related apparatus in the steel pant operating in harsh operating environment that includes dust, smoke, vibration, EMI/noise, and extremely high temperatures.

In particular, there has been a need to developing a remote control system for cast house equipment such as Mudgun and drill machine of the Blast Furnace plant to avoid the above stated limitations and disadvantages of conventional controlling of the Mudgun and drill machines.

OBJECTS OF THE INVENTION
The basic object of the present invention is thus directed to developing a system for remotely control cast house equipments of a Blast Furnace for reliable interlocking and control with reduced frequency of breakdown and improved trouble shooting and maintenance.

A further object of the present invention is directed to developing a system for remotely control the cast house equipments of a Blast Furnace involving development of a reliable method of analog and digital signal transmission using wireless media in a place where there are many obstructions.

A still further object of the present invention is directed to developing a system for remotely control the cast house equipments of a Blast Furnace which would not be using conventional control desk for control of equipments.

A still further object of the present invention is directed to developing a system for remotely control the cast house equipments of a Blast Furnace wherein a PLC based automation system has been adapted for generating sequencing and control logic for mudgun and drill machine operations. Control mechanism of mudgun and drill machine has migrated from relay based conventional automation system to state-of-the-art PLC based system with in-house software development.

A still further object of the present invention is directed to developing a system for remotely control the cast house equipments of a Blast Furnace which would be capable of wireless signal transmission suitable to work in the harsh ambience of Blast Furnace.

A still further object of the present invention is directed to developing a system for remotely control cast house equipments of a Blast Furnace which would ensure easier fault diagnosis, troubleshooting and will facilitate the reduction of downtime, to achieve higher productivity.

A still further object of the present invention is directed to developing a system for remotely control cast house equipments of a Blast Furnace which would ensure safety of operating personnel and give him freedom of operating the equipments from a safe distance.

A still further object of the present invention is directed to developing a system for remotely control cast house equipments of a Blast Furnace which can also be applied for any harsh and hazardous condition in any heavy industry.

A still further object of the present invention is directed to developing a system for remotely control cast house equipments of a Blast Furnace which shall provide a scheme to ensure seamless integration with existing hydraulic, pneumatic and automation system.

SUMMARY OF THE INVENTION
Thus according to the basic aspect of the present invention, there is provided a system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant comprising:

a portable operator station;

a wireless trans-receiver station in hydraulic room;

means adapted for sensing various analog and/or digital signals;

means adapted to control mudgun and drill machine movement;

a PLC based means adapted for generating commands for mudgun and drill machine operation, process monitoring, control and alarm generation.

According to another aspect of the present invention, the present system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant, comprising:

said portable operator station for generating analog/digital signals in relation to controlling the mudgun and drill machine;

said wireless trans-receiver station in hydraulic room having means for sensing the analog/digital signals related to said mudgun and drill machine;

said PLC based means for controlling the mudgun and drill machine movement, operation, process monitoring, control and alarm generation.

According to yet another aspect in the present system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant, the portable operator station is battery operated and comprise Radio Modem, Joysticks with toggle switches, Display panel and Emergency switch for generating analog/digital signals in relation to controlling the mudgun and drill machine to take care of all the operations of mudgun and drill machine.

According to a further aspect in the present system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant, the wireless trans-receiver station in hydraulic room comprises Radio Modem, Relay boards, Switchgears and a omni-directional antenna mounted outside the hydraulic room for remotely communicating with the portable station at a particular frequency and receiving the signals from the portable operator station.

According to another aspect in the present system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant, the wireless trans-receiver station is adapted to communicate the received signals to the PLC based means as digital inputs via relay boards.

According to a further aspect in the present system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant, the PLC based means includes CPU module, Digital input module, Digital output module, Analog input module, Analog output module and Communication module.

According to a further aspect in the present system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant, the PLC based means executes sequencing and interlocking sequences to generate set of controlling commands for mudgun and drill machine operations in form of potential free contacts and wired said potential free contacts to relay panel for driving hydraulically and pneumatically operated valves corresponding to the mudgun and drill machine.

According to a further aspect in the present system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant, the hydraulic valve comprises of:
I. Proportional valve
II. Hydraulic check valve
III. Pressure compensator
IV. Pressure reducing valve
V. Ball valve

According to a further aspect in the present system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant, the portable operator station is compact and handheld.

According to yet another aspect in the present system for remotely controlling operation of mudgun and drill machine at cast house of blast furnace in steel plant the controlling of the mudgun and drill machine by involving direct transmission of signals from the handheld portable operator station in any safe location in the blast furnace cast house reduce possibility of breakdown, thereby increasing availability of said mudgun and drill machine thereby enhancing blast furnace productivity and providing flexibility to operate cast house equipment from a safe distance.

The various other objects and advantages of the present invention is described in greater details with reference to the following non limiting illustrative drawings.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES

Figure 1 shows Scheme prior to innovation

Figure 2 shows Scheme after innovation

Figure 3 shows Portable operator station

Figure 4 shows Hydraulic valve stand

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING FIGURES

The present invention discloses a system for radio signal based remotely controlling mudgun and drill machine in blast furnace. Wireless signal transmission has been successfully implemented in one of the most hazardous area of steel making namely Blast furnace. The system of the present invention has been seamlessly adapted to old existing automation, and mechanical system. The system is totally indigenous and comprises of Radio remote control, PLC based automation system, hydraulic valve stand etc. The application and control software has been developed in-house.
The radio remote control based automation system for operation of mudgun and drill machine at blast furnace have been developed comprising the following stages (a) Design of a comprehensive schematic of remote control system, (b) Selection of proper equipment like radio modem , PLC, valve stand, amplifiers etc (c) Interfacing with the existing hydraulic and pneumatic system, (d) Installation of the system in phased manner with minimum shutdown of blast furnace, (e)Integration of the new system with existing automation system and (e) Development of operative sequence to control the process. With the installation of the new wireless signal transmission system, dependency on the control cables, conventional control desk, is eliminated for signal transmission. The deployment of the system helped overcome loss of signal due to long distance cabling. The system will also result in easier fault diagnosis, troubleshooting and will facilitate the reduction of downtime, to achieve higher productivity.

The present system for remotely controlling the mudgun and drill machine in blast furnace according to the present invention comprises a Portable remote operator station (1), Wireless station in hydraulic room (2), PLC station in control room (3) and Hydraulic valve stand (4).
In a preferred embodiment of the present system, the Portable remote operator station (1) includes Hand held portable station mounted with joysticks, selector switches and toggle switches, Radio transceiver unit, Battery unit. The Wireless station in hydraulic room (2) includes Radio transceiver station, Switchgears and relay boards and Antenna with associated cables. The PLC station in control room comprises CPU module, I/O modules, Power supply module, Switch gear, relay boards etc. Finally, the Hydraulic valve stand comprises Proportional valves, Check valves, Pressure regulators, Accumulators.

The operative sequence consists of a program which performs the following operations:
i) Reading digital signals from wireless sender via interface relays
i) Writing software to control drill machine and mudgun movement
ii) Sending output potential free contact to existing relay panel
iii) Sending analog and digital output to the new valve stand
iv) Process monitoring, control and alarm generation;

The technical specification of the major hardware components as given above, used in the wireless signal transmission system, are as follows:

1.0 Radio remote control

a) Portable Operator console receiver

Sl No Parameter Specification
1. Operating frequency 433.050-434.775 MHz
2. Ingress protection IP-65
3. Battery life 16 Hrs
4. Operating Temperature -20°C to + 70°C
5. No of joysticks 3

b) Receiver panel

Sl No Parameter Specification
1. Power supply
48/115/230 Vac+10%, 50/60 Hz
2. Operating frequency 433.050-434.775 MHz
3. Power consumption: 28 VA
4. Operating temp:
-20°C to + 70°C
5. No of output commands 29
6. Stop function Category 3 according to EN-954-1 or EN 13849 safety standards
7. OUTPUT relays characteristics 230 Vac / 8A ACI
8. Ingress protection IP65

2.0 PLC station

a) CPU cards

Sl No Parameter Specification
1. Operating temp max 60°C
2. Embedded I/O 16 DI+16DO
3. Communication options Ethernet I/P
4. Ethernet I/P nodes max 4
5. User memory 384 KB
6. Max power dissipation 12 watt

b) I/O cards
Digital input
Sl No Parameter Specification
1. Inputs per card 8
2. On-state nominal voltage 24 VDC
3. On-state nominal current 4mA @ 24VDC
4. Nominal input impedance 3.6 KO

Digital output
Sl No Parameter Specification
1. Output per module 8
2. Output type Current sourcing
3. Output current (each output point), max 1 A
4. Short-circuit protection Electronic
5. Power dissipation, max 3.02 W

Analog input
Sl No Parameter Specification
1. No of inputs 8
2. Input signal range 4…20 mA
3. Input resolution 16 bits
4. Accuracy Current Input: 0.1% Full Scale @ 25 °C
5. Power dissipation, max 0.6 W @ 28.8V DC

Analog output
Sl No Parameter Specification
1. Number of outputs 4
2. Output signal range 4…20 mA
3. Output resolution 16 bits
4. Accuracy Current output: 0.1% Full Scale @ 25 °C
5. Power dissipation, max 750 O load on each output - 1.86W

Communication card
Sl No Parameter Specification
1. Communication speed 10/100Mbits/s, half or full-duplex
2. Input Voltage Rating 24V dc nominal
3. Power Consumption 4.5W maximum @ 28.8V dc
4. Operational Temperature -20 to 55° C
5. Radiated RF Immunity IEC 61000-4-3

4.0 Hydraulic valve stand
Sl No Parameter Specification
1. Proportional valve 4WRZ 25 W8-325-7X
2. Hydraulic check valve M-SR 15 KE05-1X
3. Pressure compensator ZDC 25 P-2X/XM
4. Bladder type accumulator EHV 4-350/00 01125
5. Ball valve PKH-DN25-112A
6. Pressure reducing valve DR 30-5-5X/315YM
7. Directional spool valve 4WE6 M 6X/E G24 N94K

Reference is now invited to Figure 1, which shows earlier scheme of signal transmission between field control desks and relay panel in hydraulic room. All the control switchgear related to mudgun and drill machine control, were mounted on the corresponding control desk and bunch of control cables ran between desks and relay panel in hydraulic room. Route of the control cable, location of switchgears etc made the system un-reliable for operation. Close vicinity of control desk also created life threatening situation for the operator, because of the hot molten metal flowing nearby.

Reference is now invited to accompanying Figure 2 that schematically shows the newly implemented Radio remote based control scheme for control of mudgun and drill machine. There is one hand held portable operator station Figure 3 which has been designed in such a way that it is sufficient to take care of all the operations of mudgun and drill machine by generating analog/digital signals in relation to controlling the mudgun and drill machine. Signals from the portable console are received in a receiving station in the hydraulic room. Received signals are then wired to the PLC panel as digital inputs via relay boards. Sequencing and interlocking sequences is being run in the PLC to control mudgun and drill machine operations. After running the sequences, the PLC generates set of controlling commands for mudgun and drill machine operations. These commands are in the form of potential free contacts. These potential free contacts are wired to the existing relay panel finally to drive various hydraulically and pneumatically operated valves corresponding to mudgun and drill machine.

Reference is now invited to accompanying Figure 4, where a new valve stand has been shown. Old valve stand was of mechanic-hydraulic type, with manual handle on the control desk #2 for mudgun operation related to tap hole #2. Since the old valve stand was incapable to operate with electrical signals, a new valve stand had to be designed and implemented. Now analog command from PLC is wired to the proportional servo hydraulic system of the new valve stand. Old and the new valve stand have been kept in operation standby mode with leak proof isolation scheme.

The above stated Radio remote control based system for operation of mudgun and drill machine at Blast furnace cast house thus ensures:
a) Enhanced reliability of operation due to reduced breakdown in control desk switchgears and control cables.
b) Enhanced flexibility of latest automation system and easy trouble shooting features, by incorporation of PLC.
c) Improved response time of mudgun #2 cylinders due to incorporation of proportional hydraulic based new valve stand.
d) Improved safety of operating/maintenance personnel. Mudgun and drill machine can be operated from a safe distance.
e) Comprehensive package for signal transmission: A general-purpose wireless signal transmission system has been introduced for control of process parameters. The package developed can be horizontally transferred to other hazardous areas of heavy industries.

The system according to the present invention is thus a wireless signal transmission system for process control in a heavy industry. It is a non-contact wireless signal transmission system suitable for any hazardous location in heavy industry.

It is thus possible by way of the present invention to successfully develop and implement a wireless signal transmission system in one of the most hazardous area of iron making namely cast house of Blast Furnace. The system is totally indigenous and comprises of Radio remote control based transmitter and receiver, PLC system, hydraulic valve stand, relay panels etc. The complete application and control software has been developed in-house for operation of the said wireless signal transmission system. The successful use of wireless technology has immense potential in steel plant having harsh operating environment that includes dust, smoke, vibration, EMI/noise, and extremely high temperatures. The system developed has huge potential for technology transfer in areas like existing blast furnaces, steel melting plants, Raw Materials Handling Plant, Coke ovens, Sinter Plants etc.