Claims:We Claim:

1. An improved arrangement of hydraulically operated emergency water valve for blast furnace cast house slag granulation plant, of the steel plant comprising of:

a hydraulic valve stand with electrically (24V DC) operated DC valves and having further arrangement of pressure relief valve, isolation valve, accumulator, quick couplings and pipelines network configured for emergency opening of the water valve in case of power failure and a valve desk for remote operation.

2. The arrangement of hydraulically operated emergency water valve as claimed in claim 1, wherein valve stand is installed in the cast house and very near to the actuator.

3. The arrangement of hydraulically operated emergency water valve as claimed in claim 1, wherein the material of pipelines is SS 304 and the pipelines network have been provided with all necessary fittings as per the maximum system pressure.

4. The arrangement of hydraulically operated emergency water valve as claimed in claim 1, wherein the said piping network arrangement along with pilot operated check valves and ball valves for isolation provides leak proof holding of the load and isolation.

5. The arrangement of hydraulically operated emergency water valve as claimed in claim 1, wherein the associated feature of relief valve gives additional safety against overload.

6. The arrangement of hydraulically operated emergency water valve as claimed in claim 1, wherein the valve desk is configured for operating the said valve with the power fail condition by initializing electrically operated two position DC valves for operation of cylinders for opening when power fails and closing when the power to the solenoid is ON.

Dated: this 21st day of February, 2017.

(N. K. Gupta)
Patent Agent
Of NICHE
For SAIL

To,
The Controller of Patents,
The Patent Office, Kolkata.
, Description:AUTOMATED DRIVE ARRANGEMENT FOR THE EMERGENCY WATER VALVE OF CAST HOUSE SLAG GRANULATION SYSTEM OF A STEEL PLANT

Field of Invention:

The present invention relates to an improved arrangement for hydraulically operated emergency water valve for blast furnace in case of power failure and to ensure perfect safety of the system against the slag ingress in the system pipelines. More particularly, the invention is an attempt to make the system foolproof in the case of stoppage of pumps during power failure by supplying water from an alternate source by opening the valve automatically using the hydraulic system.

Background of the Invention:

In the hostile environment of steel plants, there are areas where safety of equipment and operating personnel are of paramount importance due to close proximity of potential hazards like hot liquid handling. INBA, or cast house slag granulation system is one such system which handles the liquid slag or the impurities coming out of the production process of a Blast Furnace. In the modern times it is very essential to get the best out of waste. Slag granulation plant is one such place where the waste slag of the Blast furnace is granulated for the production of cement.

The process involves hitting the flowing liquid slag by high pressure water jet in a confined area to granulate and cool the liquid slag. This process can be done by using various methods and INBA is one such system. To granulate the slag, the water jet requirement has to be fulfilled by running pumps and when there is a sudden power failure the stoppage of pump may lead to ingress of liquid slag in the pipelines and for this very reason with the power failure immediately the other source of water should provide water. This other source can be in the form of high level tank which is connected to the blowing box the water jet creating box, through a valve which remains closed with the power “ON” to the solenoid

In the earlier system the emergency valve was operated through the pneumatic drive and very often than not this valve was failing to operate properly when there was a need for the same. This happened mainly because either the loss of grid pressure or the failure of the direction control valve to open because of the inherent problems related to the usage of pneumatics there

Thus the existing system of opening the emergency water valve using pneumatic drive suffers from the following limitations:

1. Direction Control valve stuck up

2. Air line Pr. Low

3. Air line full of moisture

4. Air line receiver tank empty

5. Valve physically jam

As the application of hydraulics is everywhere , simple and easy to use, the very thought of applying simple hydraulics for the operation of the emergency water valve in place of pneumatics can well be thought of. In particular, there has been a need to develop a hydraulic system with power pack, field piping, cylinder and valve desk to operate the emergency water valve. This also calls for the requirement of fixing structures to hold the cylinder and the device to operate the valve. The new system needed to be put in parallel with the old system to facilitate continuity of operation and provision of a standby hydraulic power system during the regular exhaustion of the accumulated hydraulic power

Prior Art:

The original plan for operating the emergency valve has the following facilities

1. A pneumatic operated water valve for allowing the water from a high level tank as preserved equivalent high pressure system

2. Pneumatic Direction control valve

3. A ‘Filter Regulator- Lubricator’ unit , a basic requirement with the pneumatic system

4. An air receiver tank in parallel connection with the central grid of the compressed air to provide air during the compressor stoppage along with the power failure

5. Associated electrics of limit switches and power to operate the solenoid valve

Object of the invention:

1. The basic object of the invention was to provide an improved arrangement of hydraulic operated device to immediately open the valve during power failure and close it with the power recovery.

2. The other main object was to provide a system which was almost full proof.

3. The other main object was to provide a safe load holding mechanism within built load holding mechanism of the hydraulics.

4. The other main object was to enhance safety of man, machine and material as the malfunction of the emergency valve resulted in major blasts.

5. The other main object was to make maintenance of the system easy, simple and cost effective.

6. The other main object was to make the system extra reliable by the provision of isolating valves in the safe area and provision of an extra hydraulic accumulator to take care of minimum 5/6 continuous operations.

Summary of invention:

In this invention there is stress is on the reliability of the system to take care of the power failure needs in order to save man machine and material. The system deals with the conversion of the drive of an emergency valve, which as per design, was being operated by compressed air and had its limitations and thereby causing damages to the complete system, as result a reason for the losses of production of the hot metal and drop in revenue due to low granulation rate. The impetus is on the provision of a simplified system for the operation of the water valve with the use of hydraulic power. This invention also focuses on the in-house uses of the resources to facilitate the said purpose and the designing of the scheme too has been done all by the inventor himself. This system uses one hydraulic cylinder of suitable size matching with the available safe hydraulic pressure. In this system the arm has been specially designed to take care of the opening requirement of a butterfly valve, available pressure and requirement of the required torque for the valve.

To facilitate the rotary movement for the opening of the butterfly valve the linear operating device in the form of a cylinder has been used. The cylinder is a trunnion mounted cylinder which can work upto a pressure of approx. 200 bar, the one used in some other application of the steel plant and fulfills the immediate requirement of not procuring the same for the desired purpose. The power pack, required for this purpose, has not been procured and instead the system has been designed to be connected with any available hydraulic power. In this particular case available hydraulic pressure of 50 bar for the mud gun control line has been used

The pipeline has been laid for the pressure and the return line from the nearest available pressure and return line of the mud gun control system.

Brief description of the invention:

The said invention of the conversion of drive for operating the water valve of the INBA, Cast house slag granulation system:-

Fig. 1 illustrates the blast furnace, INBA slag granulation system as a prior art;

Fig. 2 illustrates blast furnace, INBA system in accordance with the present invention; Fig. 3 illustrates old emergency system as prior art;
Fig. 4 illustrates new emergency system in accordance with the present invention.

Detail description of the invention and accompanying features

The handling of liquid slag is something which cannot be abruptly stopped while the casting is

going on in a Blast Furnace and especially when the power fails, due to safety requirements of the man, machine and material, this has to work perfectly. The invention mentioned here is all about modification in the existing system with the conversion of the drive from the pneumatics to the hydraulics. The invention has the major significance in the fact that with the modification within the existing system how this can perform better without any failure overcoming all the shortcomings of the previous ones. The pneumatically operated vale for the emergency requirement is not as effective as the hydraulic could be. The design of the valve deals with the modification on the valve to fit an arm which can rotate and the proper locking of it with the shaft of the valve. The available suitable cylinder with the available stroke length was kept as the base value for the design of the lever. After the selection of the cylinder and design of the lever, the mounting of the cylinder was designed. The design of the plate on which the cylinder was to be mounted was done such that the plate can be fitted on the valve itself and can become a part of the complete valve assembly. The hydraulic power was tapped from a nearby source and the pressure of 50 bar available there was sufficient to operate the valve with water pressure at one side of the water valve. The valve desk was designed Mechanical arrangement

The butterfly valve for the emergency operation during power failure was originally with a pneumatic actuator at one end the provision for doing manual operation with the manual gear box at the other side. As the system was in running condition and the same could not be replaced with the new modified valve with the modified system, the manual gear box was removed and an arm was connected (as detailed in the fig. 3). The basis of calculation too has been shown and the mounting for the cylinder fittings for the trunnion mounted one and the suitable bearings were designed. Fig. 3 shows the load holding device in the form of pilot operated check valve for holding the load constantly.

Hydraulic power

The improved system uses the power available from the nearby sources. That way the invention is more so useful in the fact that the invention can be utilized for any such application anywhere without independently going for the new hydraulic power pack. The requirement of the torque for operating the water valve against full pressure at one side of 4kg/cm2 is achieved by operating the cylinder at 50 bar pressure only with a cylinder of 400mm stroke length and 80mm bore diameter. In this particular application this hydraulic power is obtained from the nearby mud gun control system from there the line for the pressure as well as return line have been tapped.

Hydraulic valve desk

The valve desk for this system has specially been designed with an operating philosophy of operating the valve with the power fail condition i. e. “fail to open” philosophy. Valve stand system comprises of manifold, electrically operated two positions DC valves for operation of cylinders for opening when power fails and closing when the power to the solenoid is on.

Hydraulic check valve for holding the load continuously, Pressure relief valve for hydraulic safety, Ball valves for isolation, gauges and hoses and other hydraulic components as per circuit shown in Fig. 4 for operating the emergency water valve of the CHSGP. In addition to this one bladder accumulator of 10 litre capacity has been provided to keep the system independently capable of. Fig. 4 shows the emergency power failure condition for the water system with provision of the bladder accumulator which provides back up for the hydraulic power failure too.

Actuator

One hydraulic cylinder of configuration 80x50x400, which has a maximum pressure capacity of

200 bar, has been used. The cylinder is trunnion mounted and has been mounted on the valve itself on the side is ably supported on the trunnion using the bearing.

Pipelines, Isolation Valves, Fittings etc.

The said valve stand is installed in the cast house itself and very near to the actuator. Pipeline network is laid as shown in Fig. 4. Material of pipelines is SS 304. Pipelines have been provided with all necessary fittings etc. Pipelines are of appropriate schedule as per the maximum system pressure. Isolation valves have been provided to make the system work in a working and standby configuration having leak-proof isolation with the help of the manual isolation valves

Electrics

The electrical system is provided with 24 V DC power to the suitable limit switches, isolation with switch off and linked with the PLC with the base plate design and fabrication in-house and the desk comprises of the direction control valve, flow control valve and pilot operated check valves of hydraulic size 10. The isolation valves, gauges and hoses have been provided to isolate at the valve desk itself with immediate requirement and for safety. Along with the valve desk an additional accumulator has also been provide for the power failure need of the hydraulic system itself and the accumulated hydraulic power can run the system for 5/6 cycles of operation

The valve desk has been installed at a safe location where there is no hazard of proximity to the hot metal splashes. Therefore the maintenance of the valve stand, and valves and piping network for isolation of the system is very simple.

The Inventive Step

The main inventive features of improved arrangement is an improved yet simple hydraulic device with in-house designed system to open the emergency water valve of Cast House Slag Granulation Plant, INBA to make the system foolproof against the damage caused by any power failure while the plant is in operation

Although the foregoing description of the present invention has been shown and described with reference to particular embodiments and applications thereof, it has been presented for purposes of illustration by way of examples and description and is not intended to be exhaustive or to limit the invention to the particular embodiments and applications disclosed. It will be apparent to those having ordinary skill in the art that a number of changes, modifications, variations, or alterations to the invention as described herein may be made, none of which depart from the spirit or scope of the present invention. The particular embodiments and applications were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such changes, modifications, variations, and alterations should therefore be seen as being within the scope of the present invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.