Sunday, September 25, 2011

report on BHEL IP jagdishpur


1. INTRODUCTION TO BHEL
BHEL is the largest engineering and manufacturing enterprise in India in the energy related infrastructure sector , today. BHEL was established more than 40 years ago, ushering in the indigenous Heavy Electrical Equipment industry in India – a dream that has been more than realized with a well-recognized track record of performance. Established in the late 50’s, Bharat Heavy Electrical Limited (BHEL) is, today, a name to reckon with in the industrial world. It is the largest engineering and manufacturing enterprise of its kind in India, and one of the leading international companies in the power field.
Established in the late 50’s, Bharat Heavy Electrical Limited (BHEL) is, today, a name to reckon with in the industrial world.
 First It Was Incorporated In 1964 with 3 Plants Located At
(1)HYDERABAD
(2)TIRUCHY
(3)BANGALORE.
Second Generation Plants Were Setup In Mid 70’s At
(1)JHANSI
(2)RANIPAT
(3)TIRUCHY
(4)BANGALORE
(5)HARIDWAR.       

1.1 MANUFACTURING UNITS OF B.H.E.L

First generation units:
                 BHOPAL              :  Heavy Electrical Plant
                 HARIDWAR        :  Heavy Electrical Equipment Plant
                 HYDERABAD     :  Heavy Electrical Equipment Plant
                 TIRUCHY            :  High Pressure Boiler Plant
Second generation units:
   JHANSI                  :  Transformer and Locomotives Plant
   HARIDWAR          :  Central Foundry and Forge Plant
   TIRUCHY              :  Seamless Steel Tube Plant
Units through acquition and merger:
   BANGALORE      :   Electronics division and Electro porcelain division                                                                                                            
New manufacture unit:
   RANIPAT            :   Boiler auxiliaries’ plants
   JAGDISHPUR     :   Insulator plants
   RUDRAPUR        :   Components and Fabrication Plants
   BANGALORE     :   Industrial system group
          
BHEL is growing concerns to meet the changing needs of the nation has taken it beyond power into the total gamut of energy, industrial and transportation BHEL is able to offer a total services in each of these fields. Its manufacturing capability is supported R and S division at Hyderabad work closely with research and development cells at various units and welding Research institute in Tiruchinapalli.
         BHEL offers over 180 products and provides systems and services to meet the needs of core sectors like: Power, Transmission, Industry, Transportation, Non-Conventional Energy Sources, Oil & Gas Exploration & Telecommunication. With 14 Manufacturing Divisions wide spread Regional Services Network and Project Sites all over India & abroad and with an export presence in more than 50 countries, BHEL is truly India’s Industrial ambassador to the world. All major Manufacturing, Erection and Service units of BHEL have been awarded ISO 9000 certification.
BHEL is the largest engineering and manufacturing enterprise in India in the energy-related/infrastructure sector, today. BHEL was established more than 40 years ago, ushering in the indigenous Heavy Electrical Equipment industry in India - a dream that has been more than realized with a well-recognized track record of performance. The company has been earning profits continuously since 1971-72 and paying dividends since 1976-77. 
BHEL manufactures over 180 products under 30 major product groups and caters to core sectors of the Indian Economy viz., Power Generation & Transmission, Industry, Transportation, Telecommunication, Renewable Energy, etc. The wide network of BHEL's 16 manufacturing divisions(two new added,CSU&FP), four Power Sector regional centers, over 100 project sites, eight service centers and 18 regional offices, enables the Company to promptly serve its customers and provide them with suitable products, systems and services -- efficiently and at competitive prices. BHEL is the largest engineer and manufacturing in the field of heavy electrical in India and among the leading power equipments manufactures in the world. BHEL has presence in core sector like power, industry, transportation, oil and gas, telecommunication, defense and non-convectional energy source from “concept of commissioning”. BHEL products and systems have been exported to over 52 countries worldwide.
BHEL has continuously contributed dividends to the government. BHEL also received “Excellent” rating for 9 years consequently memorandum of undertaking targets with Government of India and has conferred the price status of a “Navarathna Company” another major contribution of BHEL to the nation is by the way of its involvement in the social development work. Such as adoption of backward villages, buildings and running of schools, medical centers providing self-employment facilities for windows, handicapped persons etc.
The greatest strength of BHEL is its highly skilled and committed 44,500 employees. Every employee is given an equal opportunity to develop himself and grow in his career. Continuous training and retraining, career planning, a positive work culture and participate style of management – all these have engendered development of a committed and motivated workforce setting new benchmarks in terms of productivity, quality and responsiveness.
BHEL has acquired certifications to Quality Management Systems (ISO 9001), Environmental Management Systems (ISO 14001) and Occupational Health & Safety Management Systems (OHSAS 18001) and is also well on its journey towards Total Quality.
BHEL has Installed equipment for over 90,000 MW of power generation -- for Utilities, Captive and Industrial users. Supplied over 2,25,000 MVA transformer capacity and other equipment operating in Transmission & Distribution network up to 400 kV (AC & DC).
Supplied over 25,000 Motors with Drive Control System to Power projects, Petrochemicals, Refineries, Steel, Aluminum, Fertilizer, Cement plants etc. Supplied Traction electric and AC/DC locos to power over 12,000 kms Railway network. Supplied over one million Valves to Power Plants and other Industries .
During the financial year (2004-05), Bharat Heavy Electrical Limited (BHEL) has achieved 110% of CEA’s target of commissioning by adding 3548 MW to the national grid. This was made possible because of the advanced commissioning of a 500 MW unit (Rihand 3), not in the CEA’s plan for that period. With this the company has once again demonstrated its capability and commitment to providing maximum value to its customers
significantly, 90% of coal-based sets added in the country during the year were of BHEL make, while 80% of hydro MW addition and 79% of diesel-based MW addition was contributed by BHEL sets. Even during the current fiscal, BHEL is fully geared up to add 30 coal, hydro, nuclear and gas-based sets aggregating to 3712 MW to the country’s generating capacity.
 In addition during this period, 73% of electric energy generated by utilities in the country from coal, nuclear and hydro based units was contributed by BHEL make sets, even though BHEL-sets constitute only 65% of the total generating capacity.
 BHEL also created a new benchmark in execution of thermal power projects, with the synchronization of the 500 MW (unit 7) at NTPC’s Ramagundam STPS in a record time of just 36 months and 10 days, nearly three months ahead of schedule. This resulted in substantial saving for the customer in terms of the cost of the project and additional generation of power. Similarly, BHEL created another national record in the turnkey execution of thermal power projects last year, by commissioning the 2x250 MW Tau Devi Lal Thermal Power Station of Haryana Power Generation Corporation Limited in just 34 months. Also a new benchmark was set with the commissioning of both the units within a span of only 4 months. It is worth mentioning that even one month’s advance commissioning of a 500 MW unit results in an approximate saving of about Rs. 75 Crores to the utility.
In order to cope with the country’s ambitious target capacity addition in the 11th and 12th plan, BHEL is gearing up to enhance its equipment manufacturing capacity from present 10,000 MW to 15,000 MW annually by March, 2008. This should enable the company to play a major role in power generating capacity addition program of the country.










1.2 SYSTEM AND SERVICES:
1.2.1 POWER GENERATION SYSTEMS:


BHEL has commissioned more than 800 Nos. utility and industrial sets totaling to over 50,000 MW equivalent generating capacity. BHEL’s share in utility generating capacity was approximately 64% of the installed capacity in India in March 1993. Presently, BHEL has capacity to supply power equipment equivalent to 7000 MW per year.

(A)THERMAL GENERATION:
The unit sizes of utility stations in India range from 30 MW to 500 MW BHEL has so for being responsible for over 2000 of these installations accounting for over 40000 MW of installed generating capacity (utility) which include sets up to 500 MW capacity. The technology for manufacture of turbo generators comes from a comprehensive technical calibration agreement with Scienes AG of Germany. BHEL manufactures steam generator as per technology of M/S ABB Combustion Engineering of the USA. This technology has been acquired through 20 years of collaboration/license agreement. Both these collaboration covered unit ratings up to 1000 MW. Operating in an environment of high technology and severe competition as BHEL does, the company has perform to stay abreast with the technology leaders in the world. It is in recognition of such imperatives that BHEL has technology tie-ups around the world for a variety of power station auxiliaries as well.BHEL has a well chalked out programmed to assimilate, adapt and modify such acquired technology to suit differing economic, developmental, geographic & climatic requirement. The company has also a full-fledged Research and Development Division which undertake fundamental and applied research in power and related fields. Research; is being carried out on non-conventional energy sources as well. Several of these efforts such as those in the areas of fluidized Bed Combustion, Solar and Wind Power have already resulted in commercial ventures.

(B) HYDRO GENERATION:
BHEL has supplied Hydro Sets upto 165 MW rating and 200 MW sets are under manufacture, BHEL has facilities to manufacture and install sets of even higher rating as per specific customer requirements. It also supplies turbines for low head mini and micro hydro stations to meet the needs of rural and backward areas located in the remote corners of the country. So far, BHEL has commissioned mire than 200 Hydro Sets of various types and
capacities tattling to about 12000 MW.

(C)NUCLEAR GENERATION:
India’s first wholly indigenous Atomic Power plant at Kalapakkam near Madras is equipped with two sets of power generation equipment of rating 235 MW each supplied by BHEL. Subsequently, another two sets of similar rating have been commissioned successfully at Narora. BHEL is now manufacturing sets of 500 MW rating for nuclear power stations.


(D) GAS TURBINES BASED GENERATORS PLANTS:
Today BHEL is fully equipped to supply simple/confined cycle/cozen plants with various frame sizes of gas turbines of unit rating upto 200 MW. BHEL has collaboration agreements with two leaders of gas turbines technology in the world namely general electric, USA and Siemens AG, Germany. The agreement with GE, USA covers rating from 4.6 MW (ISO). The Siemens agreement covers unit rating from 130 MW to 200 MW. So far BHEL has
Supplied more than 33 nos. Has a turbine. All these turbines have been supplied from our Hyderabad plant based on general electric, USA technology. BHEL has bagged orders for two gas turbine based projects in Malaysia, commissioning schedule of 6- 10 months. The first project has already been commissioning in 6 months time. While the gas turbines of
GE/USA design are supplied from Hyderabad plant. With the plants (i.e. Hyderabad and Hard war) are fully equipped with state of manufacturing and testing facilities.
            BHEL is fully equipped to supply waste heat recovery boilers from their Tiruchirapalli plant. BHEL have an ongoing collaboration agreement with M/S Henry volt, USA for the Waste Heat Recovery Boilers. BHEL is supplying WHRSGS foe 6X30 MW gas turbines for Delhi electric supply undertaking, and 817 MW Dadri Project of national thermal power corporation limited besides those for other power stations.

-Turnkey power stations.
- Combined-cycle power plants.
- Cogeneration systems.
- Modernization and rehabilitation of power stations.
- Erection commissioning, operation and maintenance services.
- Spares management.
- Consultancy services.

1.2.2 TRANSMISSION SYSTEMS:


In addition to equipment for generating of power, BHEL supplies a variety of equipment for transmission and utilization of power. The company has also undertaken a number of turnkey sub-station contracts for voltage rating up to 400 kv class. Keeping with the KM long HVDC (High voltage direct current) transmission line project line for reliable and efficient transmission of bulk power.
             BHEL has in house capability to supply most of the equipment like power transformer current transformer, voltage transformers switches, insulators etc., and also possesses in house modern testing facilities. Billions of BHEL manufactured insulators of various ratings up to 160 KN are satisfactory service in many countries namely Turkey, Egypt, Malaysia, Iran, Iraq, USA Libya, Tanzania Dubai and course India.

- Sub-stations switchyards.
- HVDC transmission systems.
- Shunt and series compensation systems.
- Power system studies.
- Erection commissioning, operation and maintenance services.
- Consultancy services.

1.2.3 TRANSPORTATION SYSTEMS:
For over quarter of a century, BHEL has been supplying drives and control for traction equipment mainly to the Indian Railway, which is the third largest Railway network in the world. Today, 65% of the rolling stock in Indian contains electric of BHEL make such as traction motors, traction generators/alternators, and transformers. The company has lately moved from the position of supplier of electrics only to supplier of complete locomotives
-both diesels electric as well as A.C. Locos. The urban transportation problem demands different solutions and BHEL’s contribution extends to underground tube, light rail and battery powered road vehicles.

- Traction systems.
- Urban transportation systems.
- Erection commissioning, operation and maintenance services.
- Consultancy services.

1.2.4 INDUSTRIAL SYSTEMS:
The industry Sector of BHEL offers diverse items such as Transformers, Switcher, Rectifiers, Insulators, Capacitors, Control Gear, Valves Compressors, Pumps, Piping, Motors, Industrial turbines oilrig’s and semiconductor devices to meet the varying needs of industry.

- Industrial drives and control systems.
- Erection commissioning, operation and maintenance services.
- Spares management.
- Consultancy services.
















1.3 SERVICES:

1.3.1 PROJECT ENGINEERING:
The total engineering for thermal power stations is undertaken by a core group project engineering management. With over 500 engineers and supporting staff, this division offers specialized service in different technical disciplines and undertakes engineering works relating to optimization of cycle configuration selections of parameters and design of suitable system for power stations with a total MW capacity of 30000 and is currently involved in
several turnkey project including stations having 500 MW unit size.

1.3.2 CONSTRUCTIONS MANAGEMENT:
BHEL has a full-fledged construction management division to undertake erection work. This division well organized with over 500 experienced engineers,1000 technicians and 1300 skilled workers besides construction equipment valued at over 40 million US Dollars.

1.3.3 SERVICE AFTER SALES:
BHEL extends its supply and construction scope with service such as commissioning field engineering performance monitoring trouble shooting operation and maintenance. Renovation modernization and rehabilitation works of aged power stations are also undertaken. BHEL has a separate spare group response for insuring ready availability of essential spares to Power stations.

1.3.4 PROJECTS MANAGEMENT:
The project management division of BHEL coordinates th4 entire range of BHEL activities in relation to thermal power plant project and is responsible to the purchasing organization for compliance of the specifications. Entrusted with the overall coordination of the project the division initiates, directs coordinates, supervises and control all activities that are necessary for the performance of the project right from the conception stage until the contractual obligations are fully discharged. BHEL offers a wide spectrum of products and services for core sectors like power transmission industry, transportation, oil & gas telecommunication etc, deseeds supply of non-conventional energy systems. It has also embarked it to other areas including defence & aviation.









1.4 COMPANY OBJECTIVES
A dynamic organization is one which keeps its aim high adopts itself quickly to the changing environment. So here we are in BHEL.

Figure1.1: Vision and Misson
1.4.1 VALUES:
Ø  Strike adherence to commitments.
Ø  Foster learning, creativity and team work.
Ø  Ensure speed of response.
Ø  Respect for dignity and potential for individual.
Ø  Loyalty and pride in the company.
Ø  Zeal to excel and zest for change.
Ø  Integrity and fairness in all matters.
Ø  Most of them have been rephrased.
 "Zest for change" has been added as change has been integral with success and the rate at which change is needed is very high compared to earlier period.





2. BHEL INSULATOR PLANT, JAGDISHPUR
‘A UNIT OF BHEL’
Insulator Plant, Jagdishpur was inaugurated  on 3rd March,1984 by then Prime Minister of India  Late Smt. Indira Gandhi , as 11th manufacturing unit of BHEL in Sultanpur District, 77 Kms. Away from Lucknow on Lucknow-Sultanpur high-way. BHEL’s glorious experience in the Ceramic field with technical collaboration with M/s. NGK, Japan, the world leader in insulator technology, set the pace for the commissioning of this plant.  This unit has been provided with the most modern and sophisticated facilities.
With a view to ensure financial viability of Insulator Plant, Jagdishpur, the Unit of BHEL planned to diversified to the production of  Industrial Ceramics namely  “Ceralin” in the year 1989-90.  The Ceralin production for commercial use was started in 1993-94.  The ceralin was the product being manufactured in BHEL’s Electro porcelain Division, Bangalore and Insulator Plant Jagdishpur got a technologically established and commercialized product.
       For increasing the production of ceralin BHEL Insulator Plant installed a modern Bell type High Temperature Kiln(NEUTEC BIKLEY) in the March 2009. This HTK  has firing capacity of 4 to 5 ton.
BHEL Insulator Plant, Jagdishpur is the leading manufacturer of High Tension Porcelain Insulators and Distribution insulators like Bobbin/Shackle, Guy/Stay/Strain, Pin, Cap & Pin type Post Insulators in the country.  They are equipped with highly sophisticated plant and machinery.  This division also offers Wear Resistant High Alumina Ceramic Lining material for Power, Steel, Cement and Mining Industries as well as a wide range of Industrial Ceramics. 
BHEL Insulator Plant, Jagdishpur has attained ISO 9001 certification in 1994, ISO 14001 and OHSAS 18001 certifications in 2002 for its well established systematic production systems, standards, environmental management and safety management.
In addition of these BHEL IP has got certification of merit in RKBNQA in the year 2009. This shows the dedication of each individuals of unit for the quality of works and product.
The insulator plant BHEL, catering to electric power transmission business by way of manufacture and supply of disc insulator. Presently the plant is geared to produce 19 thousand tons of disc insulators annually and one thousand tons of Ly. of insulators. Over the year lot of technological innovation have taken place in the plant which has streamlining of manufacturing processes & has taken it in to the level of best industry. New type of disc insulator has also been introduced periodically and today it manufactures disc insulators up to 160-Kn.Stength ranging from normal to antifog type. The plant has till date executed many prestigious export contracts and has supplied disc insulators to Turkey, Malaysia, Trinidad & Tobago, Ghana, and Nigeria etc.
Since 1994, low tension types of insulators have also been introduced in the product range in addition it supplies to domestic market quantities have also been exported to countries like UK & South Africa. In present area of liberalization the company has not only gone for diversification but also has taken concrete measures for organizational and product improvement by ISO-9001 certification and adopting iqm approach. In the present world an attempt has been made to system erotically analyze the export market requirements of insulators and identify the product forming bulk exports. The world market scenario of insulators imports have been presented with a view to provide strategic global market information for insulator exports.
BHEL’S more than 40 years experience in the ceramic field ,blended with that of NGK, Japan’s world leader in insulator technology, set the pace for been provided with the most modern and sophisticated facilities, and was commissioned in a record line of 18th months.
            Insulator plant Jagdishpur has developed into one of the India’s disc insulator manufacturing centers with the most streamlined layout and modern technology.It6 has provisions to cope with latest advances in the ceramic field.

2.1 OBJECTIVES AND GOALS OF INSULATOR PLANT:
1.      Appropriately Integrate Manufacturing with Technology development and further technology development with marketing.
2.      Thrust on Export Marketing.
3.      To maximize the Business in Ceramics Area by Business Development, Engineering and Technology Management (Technology acquisition/Technology development/ Job to job tie up etc.).
4.      To ensure earning on capital employed through efficient and effective use of resources and enhance stake-holders interests.
5.      To produce quality products in the field of Ceramics and attain & sustain a good market share in Ceramic Industry of India.
2.2 PRODUCT    RANGE:
Ø  Disc Insulators up to 210 kN strength for transmission lines up to 765 kV AC, 500KV and 800kv HVDC Disc Insulators.
Ø  Hollow Bushings for 11kv and 33kv kV Systems.
Ø  Bus bar support for 11kv and 22kv line.
Ø  Ceramic Liners (Ceralin) for wear resistant applications.

2.3 MAJOR RIVALS OF ‘BHEL’ INSULATOR PLANT, JAGDISHPUR:
v   Jai shree insulators, kolkata (birla group)
v   Ws insulators, kolkata (west bengal)
v   Modern insulators, chennai
v   Iec, kolkata (west bengal)
v  Bathinda ceramics, punjab
v  Hi-tech, khurja (u.p.)
v  Power tech, khurja (u.p.)







2.4 MAJOR CUSTOMER OF ‘BHEL’ IP JAGDISHPUR:
Jagdishpur insulator plant has some important customer which are state electricity board, government organizations, public sector units and private customer and Indian railways.
2.4.1 STATE ELECTRICITY BOARDS
v   UPPCL
v   MPSEB
v   GEB
v   PSEB
v   KSEB
v   KPTCL
v   TNEB
v   MSEB
2.4.2 PUBLIC SECTOR UNITS
v   POWER GRID
v  NTPC
v  NHPC
v  DVC
v  NLC
v  Government Organizations
v  Govt. of Tripura
v  Govt. of J&K
v  Govt. of Mijoram
v   Govt. of Manipur
2.4.3 PRIVATE CUSTOMERS:
v  Jyoti Structures Ltd.
v  JSPL (Jindal Steel Power Ltd)
v  Associated Transrail Strucrures Ltd
v  RPG Transmission Ltd.
v  Tata Project
v  Ramji Power Construction
v  EMC (Electrical Manufacturing Company)
v  KPTL (Kalputra Power Transmission Ltd.)
v  Devang  Electricals









3. PRODUCTION OF DISC NSULATORS

                            
                                                                 Figure 3.1: Disc insulator


Figure 3.2: Internal structure of disc insulator

3.1 TECHNICAL CHARACTERISTICS:

Rating                      :    45 kN to 210 kN EMS
Creapage Distance   :    192mm to 380mm
Locking Device       :     R / W Type in PB / SS
Glaze Color              :     Brown / Grey
Applications             :    Transmission Lines from 11 kV to765 kV AC & 500 kV   
                                      and 800 kV HVDC, Substations
3.2 PROCESS FLOW CHART OF DISC INSULATOR MANUFACTURING:
Weighment of Raw Materials in Slip House
SHX

Ball mill



Blunger
Scrap
Finishing
Tunnel Drier
Oil Inspection
Scrap
Glazing
Loading- KILN
Visual Inspection
Porosity
Scrap
Assembly
Bituminous Paint, Thinner
Spray
Scrap
Scrap
Thermal Cycle
Test
Hydraulic Testing
Curing
Testing
Metal Parts


Packing & Storage
Dispatch
Scrap
Security Clips & Packing Crates
 Filter press
& Pugging
Jiggering

Figure 3.3: Process flow chart
 


 

v  Jiggering                :       Forming Process
v  Finishing                :       Dimensional control & Surface smoothening to enhance
v  Extrusion               :       Filter press cakes to Blanks Glaze adherence
v  Drying                    :      Removal Moisture to < 1%
v  Inspection              :       Segregation of defective insulators
v  Glazing                   :      Application of glaze ( Brown/ Grey )
v  Firing                      :      Tunnel kilns / batch Kilns
v  Inspection               :      Segregation of defective insulators
v  Hydraulic Testing   :      Weed out defective insulators at Head portion
v  Thermal Test           :     Withstand thermal shock
v  Assembly                :     Joining of Metal parts ( Cap and Pin) with Cement
v  Curing                     :     Hardening / Strengthening of cement
v  Final Test                :     Mechanical Test ( At 40% of rated ) and High voltage ,
                                      High  Frequency Test      
v  Packing and Dispatch



Figure 3.4: Process flow diagram


















3.3 SLIP HOUSE:
The slip house performs the following operations. All these materials are used in different quantities for different type of insulators that are manufactured and demanded by the customers.
 The raw materials required for manufacturing the insulators are:

FIRST CHAEGE:
·         Quartz
·         Feldspar(stone powder)
·         Pyrophillite
·         River pebbles
·         Bikaner clay
·         Felsites
·         Alumina

SECOND CHARGE: These are different type of clay.
·         Than clay
·          Ellure clay
·          Ball clay
·         Chaibasa clay
·          Japan ball(J.B.)clay 
·         China clay


Figure 3.5: Block diagram of slip house



3.3.1 WHEREHOUSE:
The production in the BHEL runs 365 days, and it is a continuous process. Here raw materials are tested before manufacturing the insulators so that raw materials obtained from places satisfies their requirements.

3.3.2 CRUSHING PLANT:
Above said materials other than clay are available in the stone form. Crushing plant is used to crush these raw materials into powder form and also it is used to powder the rejected ones for recycling.

3.3.3 WEIGHMENT:
 The raw materials are required to be mixed in different composition. Therefore weighment of raw material is done. Different raw materials from the storage bins are collected and weighed according to the percentage composition given by the E&D and according to the ball mill capacity to be charged. Then the weighing card is attached to the lot.
            A sample data for preparation of suspension body slip in a 5 ton ball mill for the first charge are as follows:

Quartz
1053 kg
Feldspar
603 kg
Bikaner clay
387 kg
Pyrophylite                                                      
653 kg
Felcite
201 kg
Pebbles

157 kg(due the presence of previously
charged pebbles in the ball mill)
Table 3.3.1: Composition of slip
    
3.3.4 CHARGING:
It is a preproduction section. Before the actual production starts the raw materials have to undergo a certain specific process. In the slip house the raw materials are got from the material management department. These raw materials are mixed into certain composition according to customer need then these are fed to ball mills.

3.3.5 BALLMILL:
Above said materials other than clay are available in the stone form. Crushing plant is used to crush these raw materials into powder form and also it is used to powder the rejected ones for recycling. The raw materials are required to be mixed in different composition. Therefore weighment of raw material is done.
 Weighted raw materials including clay are mixed with sufficient water i.e. 50% of raw materials and 50% water and grinding in the ball mills for duration of (17+3) hours; it is a continuous process round the clock. In the first phase of charging feldspar and quartz is mixed with water for 17 hour, after that clay is mixed for next 3 hours. The materials obtained in the ball milling process are called slip or ceramic slurry.

3.3.6 RIVER-PEBBLE CHARGING:
For initial charging of river pebble in the ballmill after rolling large ,medium and small pebbles are collected as per standard samples and weighted as per specification number(PPSL: 0100 R-2 )and pebbles are charged as per the quantity specified.
The raw materials are loaded per composition into "ball-mills". In ball -mills  'river -pebble' are put as grinding   -media. When ball -mill is operated the grinding media and raw material produced the file paste called 'slip'. The ceramic slurry got from the ball mill is fed to the vibrator screens to check for the correct accumulation throughout the materials and also to remove solid particles. Then the material will be having too less impurities and then goes for filter press to extract water by pressing that ceramic body with high pressure This slip is the input for the 'filter- presses to produced the 'cake'. This cake is output of slip -house and serves as input for manufacturing Jiggering.

3.3.7 PREPARATION OF FIRST CHARGE BODYSLIP:
 Weighed quantity of first charged raw materials is charged into the ball mill by attaching a cone to its hole from the charging hole on the platform. The pebbles are cleaned with water before charging and then specified quantity of water is charged into the ball mill. Generally charging takes 1-2 hours and ball mill runs 14-16 hour.

3.3.8 PREPARATION OF SECOND CHARGE BODY SLIP:
 Weighed quantity of second charge is charged into the ball mill with required quantity of water after preparation of first charge body slip and the ball mill is run for specified time. Then the slip is discharged into the mixing tank and is agitated continuously.

3.3. 9BLUNGING RETURNS SLIP:
 Scrap and water returned by the process is charged into the blunger in specified proportions to get required specific gravity of the slip. Then it is blunged to achieve homogeneous slip.

3.3.10 VIBROSCREENING – SEPERATION/DEMAGNITIZATION:
Here the slurry is transferred to the tank from the ball mill to remove the unwanted materials like threads of the plastic bags in which the raw materials are stored, wooden pieces through vibration and electromagnetic separation. This tank is called discharge tank.

3.3.11 SLIP AGITATING:
After screening, the ceramic slurry is transferred to another specially built bank called top tanks. From this it passed through two vibratory screens which will be rotating continuously to avoid accumulation of raw materials at the bottom and after on top. Then the mixture is fed to Ferro Filter for removing the iron particles. Finally the fresh slip is collected in the fresh tank or storage tank.


3.4 PREPARATION OF CAKE:
The slip from the initial tank is pumped into the press using plunger pump and then adequate pressure is applied to turn it into a cake. Here the slip house work is complete.

3.4.1 FILTER PRESSING – DEWATERING:
It is dewatering process. In this process 80% of the water is removed from the slip so as to convert the slip into cake form using nylon clothes. In this process high pressure is applied by compressing them from both sides.

3.4.2 PUGGING:
It is a de-airing operation under vacuum. The cakes are filled into pug mills to remove air bubbles present in the cakes. In the pug mill homogenous mixing of cakes takes place. The product which comes out after pugging process is called as blanks. Blanks are extruded from the pug mills in the cylindrical form of different sizes for different types of insulators. In this process the moisture content is reduced up to 22%. Cylindrical Blanks are shaped conically by pre shaping machine to facilitate Proper compaction during forming process.

3.5 JIGGERING – FORMING OF DISC INSULATORS:
The input for Jiggering station is cake produced by slip -house. The cake are fed into 'pug-mill', which under vacuum homogenous Cake in cylindrical form, which is cut automatically in required length (as per product), called pugs. These pugs are fed into Jiggering machines, which at first go impart initial shape of insulator shells. The secondary or final die gives the final shape shell. These green stage shells are dried in CD (chain-dryer). After drying these shells are taken out of modes and send for finishing.
Pre-shaping blanks are placed into Moulds which inner side has lining of plaster of paris and shaped on Automatic Jiggering Machine. To avoid sticking between The Die and the mould, a mixture of Kerosene oil and Coconut oil is used as Lubricant.
Aluminum Bronze Dies machined and carefully profile finished are used to Shape the insulators. Profile shaped by the Die will not be disturbed further. Insulators are ensured for defects free. Mould will have Aluminum outer Casing for strength and lining of Plaster of Paris – porous material with water absorbing property which facilitates to separate the insulators some time after Forming Jiggering.

3.6 DRYING:
Insulator after forming are dried In Chain Dryers at 30 to 35 degree centigrade for about 2 to 3 hours to facilitate separation of Insulator from the mould easily.
The different drying steps are as follows:

3.6.1 CHAIN DRYER:
These dries are used for drying the disc insulators. After this process the insulators will be having less than 15% moisture.


3.6.2 BLANK DRYER:
For hollow insulator and solid core insulator the blanks produced by pug mills are directly fed to these blank driers. For making the hollow insulators and solid core insulators the hardness of blanks is very much necessary. Therefore blanks are dried to see that the moisture content is less than 15%.

3.6.3 MOULD RELEASING OF DISC INSULATORS:
Insulators are separated from moulds over Aluminum Ring which supports Green Insulator and helps in handling the Insulators at further stages. Insulator are loaded gently to the Racks and moved to Humidity controlled storage chambers to attain leather hard condition (stored for 10 to 12 hours at ~ 60% Humidity).

3.7 OIL INSPECTION:
After the disc insulators are dried from chain dryer, they will go for finishing operation. Those processes give a perfect shape for the product and then the visual and oil inspection is carried out for the quality of the product.

3.8 FINISHING:
The article is placed on the rotating wheel and adequate layer of mass is removed without affecting die formation. Dimensional control & Surface smoothening to enhance Glaze adherence .Insulators of specified Hardness (Moisture content) finished for Specified Dimensions like-Head diameter Head diameter and Thickness are the most critical dimensions being maintained stringently.

3.9 INSPECTION- SEGREGATION OF DEFECTIVE INSULATORS:
Insulators are inspected for different Defects. Originated due to stresses induced during forming, mould releasing, and handling, based on the Position helps in analysis and initiating corrective steps at previous stages.












3.9.1 DEFECTS IN INSULATOR:

Figure 3.6: Defect in insulator


3.9.2 SOME OTHER DEFECTS:
a.       EHM- Mistake takes place due HAND MISTAKING by worker. This can take place due to carelessness.
b.      EFT- It is finishing defect. It can take place shaping process.
c.       PH- Pin home defect due to jiggering.
d.      RT- Ring touch defect due to poor handling.
e.       EMT- Manufacturing defect.

3.10 TUNNEL DRYERS (T.D.):
The disc insulator after inspection goes into tunnel dryers for further drying.
There are two tunnel dryers, each dryers has 5 zones of temperatures.

Zone   
Temperature range
Zone1
33o C to 47oC
Zone2 
48oC to 62oC
Zone3
minimum 70oC
Zone4   
85 to 103oC (Heating zone)
Zone5
minimum 65oC
Table 3.2: Temperature range of kiln

In this process the moisture is removed through stream. After the drying each product will have less than 1% moisture in it. This model of drying is called drying chamber.

3.11 GLAZING:
 After the model drying is over all the types of insulators goes for glazing. Glazing is a process to give the required color to the insulators like red, brown, black and white. Glazing is done to give a coating of 0.3mm to 0.5mm of thickness. Glazing results in improved mechanical and electrical stability characteristics.
Good Insulators are glazed in Automatic Glazing machines (AGM). Specified Specific gravity, viscosity and thickness are maintained to enhance the Glaze impact on the insulator.
Ø  Sanding is done on pin portion and Head portion of Glazed insulators to facilitate better grip while cementing the Metal parts and improves Mechanical characteristics of the Insulators.
Ø Stamping Identification made on the insulators based on the customer requirements and Standards.

3.11.1 ADVANTAGES OF GLAZING ARE:
v  Good looking.
v  Additional strength.
v  Clustering surface.
v  Smooth surface & long life.

3.12 FIRING OF DISC INSULATOR:

3.12.1 TUNNEL KILNS / BATCH KILNS:
Glazed insulators are loaded to wagons and fired at temperature at 1245 to12550C in Gas Fired Tunnel Kilns. The firing work is done in the kiln. It is a continuous process and the kiln temperature and cycle is maintained according to the instructions of the E&D. This is done to test and check the suitability of the product according to the specifications mentioned during the whole process.
        
3.13 INSPECTION- SEGREGATION OF DEFECTIVE INSULATORS:
After Firing 100% Inspection is carried to Identify Mfg defects, glazing defects, Loading defects and Kiln defects for Analysis and to initiate corrective actions at previous stages.

3.14 TESTING OF INSULATOR:
After firing the insulator goes for testing.
The various types of tests are: -
Ø  Hydraulic pressure test
Ø  Thermal test
Ø  Mallet test
Ø  Electrical flashover test.






3.14.1 HYDRAULIC TESTING:
100% Insulators are tested to weed out defective at Head portion. In this test a 200 kg/cm2 pressure is applied at the head portion of the insulator.

Figure 3.7: Disc insulator


3.14.2 THERMAL TEST:
 Withstand thermal shock, 70 degree centigrade difference between cold water and hot water should be maintain .In this test first of all insulator is placed in the hot water for 15 minutes and then it drain into the cold water. During this test there should be no crack come into the insulator.

3.14.3 ASSEMBLY OF METAL PARTS:
The metal parts, cup and pin are joined here. To join the metal parts there is a special type of cement known as alkreet cement is used. After assembling, the insulator goes for curing (drying) operation. The different kinds of curing are steam curing (2 and half hours), hot water curing (3 days) and air curing (1 day).

3.14.4 MECHANICAL TEST:
The complete insulator string along with its hardware fittings excluding arcing horn, corona control ring/grading ring and suspension assembly/dead end assembly shall be subjected to a load equal to 50% of the specified minimum ultimate tensile strength (UTS) which shall be increased at steady rate to 67% of the minimum UTS specified. The load shall be held for five minutes and then removed. After removal of the load, the string components shall not show any visual deformation and it shall be possible to disassemble them by hand. Hand tools may be used to remove cotter pins and loosen the nuts initially. The string shall then be reassembled and loaded to 50% of UTS and the load shall be further increased at a steady rate till the specified minimum UTS and held for one minute. No fracture should occur during this period. The applied load shall then be increased until the failing load is reached and the value recorded.

3.14.5 ELECTRICAL TEST:
After curing, the insulators are set for final electric testing. If insulators fail in this test, it burns out and thus they are rejected.
          In electrical testing the insulator is passed under high voltage line of rating near about 3 to 4 times of rated value for four minutes. If a yellow color light flame appears across the insulator then it will be rejected due to poor flashover capacity. If it is able to withstand with high voltage then it is labeled by a green symbol and send to dispatch.  

3.15 PACKING AND DISPATCH:
The insulators, which are successful in the tests, are sent for packing section. The insulators are well packed in crates to avoid damages during transportation and ease smooth handling. Thus, the time taken for all this activities crushing to packing is 31 days.





















4. MANUFACTURING OF HOLLOW BUSHINGS


Figure 4.1: Hollow bushing


These are two main type of insulator for apparatus at sub stations. They are the hollow porcelain used for the transformer bushings, and the subject insulators used for supporting the bus lines.

4.1 PRODUCT RANGE:   Hollow bushings 11 kV and 33kV










4.2 PROCESS CHART OF MANUFACTURING:

DISPATCH

RAW MATERIAL
WEIGHMENT
WET GEINDING (BALLMILLING)
SLIP PURIFICATION
FILTER PRESSING
PUGGING
TURNING
DRYING
GREEN INSPECTION
FIRING
LOADING
GLAZING
INSPECTION
TESTING
GRINDING

PACKING
TESTING
ASSEMBLY
 























Figure 4.2: Block diagram of manufacturing of bushing

After the formation of cake in the filter press, the material is fed to pug mill. A blank is formed which is then dried in blank drying chamber to reduce the moisture content below 15-16%. Then the material is given for turning where vertical lathe is used. After a desired shape is attained then the model is send to model drying chamber (MDC) to decrease the moisture content less than 1% and then it is glazed & fed to kilns for firing.

4.3 PUG MILL:
The cakes obtained from filter press are automatically / manually fed into the pug mill. The pug mill has three chambers namely primary chamber, vacuum chamber and final chamber. In the primary chamber the hopper blades and single helical screws are provided. The cakes which are fed will be chopped in to small bits and pushed forward by the screw. The material comes to vacuum chamber thro slit plate. In the vacuum chamber the required vacuum is maintained to remove any air pockets in the body. The main purpose of the pugging is de-airing and kneading for blank extrusion .The obtained blanks are cut into required size and are sent to blank drying chamber.
                                        
4.4 BLANK DRYING CHAMBER:
The moisture content required for the blanks for shaping process is about 16% to turn the model. During drying, water evaporates slowly resulting in uniform shrinkage and hardness. It is necessary to have controlled drying to avoid stress.

4.5 TURNING:
The conditioned blanks are turned on vertical lathes (Manual and CNC lathes).The inner surface of bushing, turned by the help of lathes machine. The smooth surface is required for the purpose of safe conductor.

4.6 NATURAL DRYING BEFORE FINAL DRYING:
The hollow bushing is put up in the air for drying up to some extent.

4.6.1 FINAL DRYING:
The articles are further dried in thermal fluid dryers and tunnel driers to less than 1% moisture content.

4.7 INSPECTING GREEN INSULATOR FOR DEFECTS AND DIMENSION CORRECTION:
Insulator is inspected by manually and defected insulator has been removed. By this we can save our energy and raw material.  

4.8 GLAZING:
Glaze is prepared in the similar method as Insulator body slip is prepared, with some changes in the composition. Metallic oxides are used to get the desired color of the glaze.The physical properties of glaze i.e., specific gravity and viscosity are maintained as per the specification at the time of application on Insulators.




4.8.1 GLAZED & FIRED INSULATOR:

 
Figure 4.3: Green and fired insulator
   
4.9 ASSEMBLY OF INSULATOR WITH METAL PART:
The metal portion of hollow bushing is set in this process. The metal part is used to connect from other auxiliary instrument. The metal part can be assembling by cement pouring process. In this process the cement is filled up between metal and insulator.  

5. ROUTINE TESTS:
Mechanical, electrical, thermal, pressure tests are carried out on all insulators as per requirements.                                

5.1 TESTING AND ASSEMBLING SECTION:
There are several tests to be carried out to check for the quality of the product. These tests include:

5.2 HYDRAULIC PRESSURE TEST:
 In this a huge amount of pressure will be executed to the fixed insulators (disc) at an order of 180 +/- 20 kg/cm2 for insulators ranging from 70 KN to 210 KN and of order 200 +/- 20 kg/cm2 for 320 KN disc insulators.

5.3 THERMAL TEST:
 The insulators, which are successful in the hydraulic pressure test, are subjected to thermal testing. In this testing the insulator are dipped in hot water at 90 degree Celsius. Then within 60 seconds it has to removed from the hot water and has to placed in the cold water which is having a temperature around 20 degree Celsius. This test is done to see its withstanding capacity for fluctuation in temperature. If the insulator fails to withstand the fluctuation in temperature, small cracks will appear.

5.4 MALLET TEST:
 In this testing, the insulators which have gone thermal testing are beaten using nylon hammer of 1.5kgs on the top and the side of the insulator. If there is any small crack, it will be revealed and thus are rejected.

5.5 ELECTRICAL TEST:
Insulator is subjected to routine electrical testing at 70 KV to 80 KV for 4 minutes, 1 minute for high frequency power test and 3 minutes for high voltage power test. If it fails in the test, it punctures and thus rejected.
            These tests are done before assembling. Then the units go for assembling where special, crock, cap, pin are placed using cement and is fed to steam dryer for initial setting and then finally goes into hot water for 3 days and 1 day to steam. This final product again goes for electric resting at 150 KV and the successful insulators are sent for dispatch after packing. To do all these works are artisans separately for assembling and testing, above them is the senior engineer and above them is senior manager.

5.6. PACKING & DISPATCH:
In this section the packing of hollow bushing take place. The insulator is bind in between jack of wood. Finally it is send to dispatch unit for the purpose of customer.













6. CERALIN DEPARTMENT
 

















Figure 6.1: Ceralin fitted in pipe






Ceralin is having major presence in coal fired thermal power stations, Cement sector & Steel Sector. Major customers list includes NTPC, DVC, Jindal, Tata Power, Nalco, Hindaco, HZL, Torrent Power, State Electricity Boards for their Power Stations, SAIL and Cement companies.
            An inherent part of any processing plant, big or small its material handling systems. Because of continuous usage, these systems are subjected to a large amount of wear and tear. Two factors affecting this are abrasion and erosion due to material flow.

6.1 NEED OF CERALIN:
Ceralin a total solution against wear in steam generating units {boilers} and associated pulverizes and other auxiliaries, high alumina ceramic material can be used for protection of components against wear due to abrasion and erosion.
            Coal is one of the main sources of fuel used in power generation. Coal fired boilers adopt the method of pulverising raw coal in pulverisers or mills, conveying the pulverised coal-air mixture from the pulverisers to the boiler burner for producing and utilising steam to generate power. Fine coal particles at high velocities cause failure in many components in the pulverisers and the coal piping system of the boiler. Ceramic lining is provided to the components to extend the life thereby reducing downtime. Its superior wear resistance, chemically inert and high thermal stability characteristics make CERALIN suitable for a wide range of applications:

Power Sector     :  Wear prone components of Bowl / Tube Mill, Fuel Piping.
Steel Sector        :  Sinter Plants, Rotary Kiln, Coke Oven
Cement Sector   :  Cement & Raw Mills chutes & Air Separators
Coal Sector        :   Slurry Pipes, Chutes & Launders.

To combat the various wear prone areas in Coal fired Thermal Power Stations, Coal
Sector, Steel Industry, Cement Industry and others similar applications, BHEL has indigenously developed High Alumina Ceramic Wear Resistant materials in its R&D.
Components fitted with CERALIN are used all over India with a proven performance
The Ceramic Business Unit (CBU) of BHEL, is a Strategic Business Unit for Ceramics and Systems. This business unit deals with High-tension Insulators, Ceramic Wear Resistant liners, Industrial Ceramic Products and associated Systems. CBU is headquartered at Bangalore and is supported by:

Manufacturing units with “State of the Art” technology for ceramic products, processes and applications at:
Electroporcelains Division (EPD), Bangalore
Insulator Plant (IP), Jagdishpur

Advanced Research and Development facilities for Ceramic products, processes and
Applications at:
Ceramic Technological Institute (CTI), Bangalore (A Division of Corporate Research
& Development, Hyderabad)

6.2 PHYSICAL PROPERTIES:
Volume of Material lost in cubic centimeters per ton of ash

6.2.1 TEST CONDITIONS:

Particle Velocity
50 m/sec
Erodent
Ash concentration of 0.25 kg/ Nm3
Period of Test
60 min
Angle of Impingement
 450
Table 6.1:Test condition


Figure 6.2: comparison of ceralin with other material

6.3 OPERATING CONDITIONS:
In coal fired steam generating units the normal operating conditions are:
Flow medium                  
Pulverised coal mixture
Particle size                     
70% less than 75 microns
15% 75 to 90 microns
15% 90 to 150 microns
Coal concentration           
0.935 to 1.545 kg/Nm3
Ash content                      
50% Maximum
Flow velocity                     
30 mtr / Sec. Maximum
Pressure 
0.5 kg / cm2
Temperature  
300oC Max
Table 6.2: operating condition of ceralin
The components are designed to meet the operating parameters and life expectancy considerations. If the operating condition is not as like above then the ceralin will not give its best performance.

6.4 PROCESS FLOW DIAGRAM
Ball Mill

Spray Drier


Tile Pressings
Raw Material Weighment & Loading In Slip House (Ceralin)
POWD E
R
Scrap

Loading / Firing
HTK
Assembly / Lining

Metallic Casings
Finished Product
Dispatch
 























Figure 6.3: Block diagram of manufacturing of ceralin
6.5 MANUFACTURING PROCESS:
Alumina which is the main constituent of ceralin, mixed with other additives in the specified proportion i.e. 85% alumina, 10% clay and 5% manganese  in ball mills. The resulting slurry is mixed with organic binders i.e. PVA in a planetary mixer, after dewatering and drying  through spray dryer, it is granulated and this mixer is then compacted through a hydraulic press into the required shape of tile and sinter in modern PLC controlled kiln i.e. in HTK or NUTEC BICKLEY up to 1520 degree centigrade. Depending upon the nature of application, these tiles are fixed to the base metal by using cement.
Average days required for production is 15 days. In order to reduce the pollution control they have produced ceramic honeycomb substrates, the heart of a catalytic converter for automobiles for clear emission. Ceramic honeycombs are thin walled, multi chambered cellular structures formed into monolith by expression. They are characterized as having large surface areas, excellent thermal shock resistance, high strength and light weight. Such design and properties make honeycomb substrates ideal for catalytic reaction.
In a catalyzed honeycomb substrates are created in a metal car and fitted in the exhaust stream of as automobile. Exhaust gases pass into the converter and through the multi channeled substrates where they make contract with the catalyst coated walls as they interact with the catalyst, the harmful gases such as carbon monoxide, Hydrocarbons and Nitrous-oxide are chemically changed into less toxic compounds such as carbon-dioxide, Nitrogen and water vapor. 

6.5.1 BALL MILL:
In ball mill the crushing of raw material take place. The raw material is mixed with water crushed out. The output of ball mill is slip.
 
 

Figure6.4: Ball mill

6.5.2 SPRAY DRIER:
In spray drier the slip is converted into powder form. For this first of all the slip is moved against the fire flame. The slip comes from upper side of drier and the elevated from lower side. At junction of slip and flame the slip become dry due high temperature. So we got the powder of slurry. 
 


Figure 6.5: Spray drier

6.5.3HYDRAULIC PRESS:
Spray dried powder is then compacted in Hydraulic Presses to form tiles. These tiles are then fired in a high temperature kilns at around 1560-1600oC to get required wear resistant characteristics. Ceralin tiles assembly to the casing is done by using Mortar, Silicone adhesives or Weld-on tiles.
 
6.6 KILN SECTION:

Kiln is the refractory lined structure where ceramic articles are fired to develop various properties like mechanical strength, electrical properties, translucency, chemical inertness etc. Firing by burners can be done in two ways, either side firing or end firing. The fuel used may be oil or gas.

6.6.1 TYPE OF KILNS:
There are two types of kilns -
v  Continuous Kiln (OTK)
v  Shuttle Kiln (SK


6.6.2 CONTINUOUS KILN:
It runs continuously and is desired for mass production of ceramic articles to cater continuous demand. In such kilns, articles are charged at one end and discharged at the opposite end. Apart from firing, cooling is also done inside the kiln itself. Once stopped, it takes considerable time to generate required atmosphere for firing. For example, tunnel kiln.

6.6.3 SHUTTLE KILNS:
It runs intermittently, when required. Unlike continuous kiln, it has only one door. Charging & discharging are done through the same door.  In this type of kiln, articles are loaded and the door is closed. After firing, the kiln is stopped. On subsequent cooling, articles are unloaded. Firing of green insulators Bushings are carried out in this Kiln.

6.6.4 TUNNEL KILN:
It is a continuous type of kiln having a capacity of 20MT/day. It was commissioned way back in 1983. Mostly, disc insulators are fired here.. Its total length is 120m and is divided into three following zones as below:

PRE HEATING ZONE   
34.55 METERS
HOT ZONE                   
36.25 METERS
COOLING ZONE             
49.20 METERS
Table 6.3: Description of heating zone in tunnel kiln
             
    
6.6.5 SALIENT FEATURES OF TUNNEL KILN ( IP):

TOTAL LENGTH OF THE KILN                                  
120  MTS
WIDTH OF CAR SETTING                                            
1415 MM
HEIGHT OF CAR SETTING                                          
1810 MM
LENGTH OF PRE-HEATING ZONE                            
34.55 MTS
LENGTH OF HEATING ZONE                                      
36.25 MTS
LENGTH OF COOLING ZONE                                    
49.20 MTS
NOS. OF CAR IN PRE-HEATING
17 CARS
NO. OF CAR IN HOT ZONE
18 CARS
NO. OF CARS IN COOLING ZONE
23 CARS  
LENGTH OF THE WAGON
2006MM
NO. OF CAR IN OXI. ZONE
07
NO. OF CAR IN RED.ZONE
10
NO. OF CAR IN NEU.ZONE
01
TOTAL NOS. OF CARS  IN KILN
58  CARS 

Table 6.3: Description of tunnel kiln

C-1=  80,    C-2 = 340,    C-3 = 470,   C-4 = 670,  C-5 = 750 ,  C-6 =875,    C-7= 1000,  C-8 =1050,  C-9=980,  C-10=1050,  C-11=1150,  C-12 =1225,  C-13=1250,  C-14=1225,      C-15 =1120,  C-16=1000,    C-17=880,  C-18= 620, C-19=400,  C-20=70

B-3/4=875, B-5/6=930,  B-7/8=940, B-9/10=890,  B-13/14=990, B-15/16=1060
B-17/18=1140,  B-19/20=1180,  B-21/22=1220,  B-23/24=1285

 6.6.7 CROWN POSITION IN RESPECT OF BURNERS (IN HOT ZONE)                   
C-6=B-1/2, C-7=B-3/4&5/6,  C-8=B-7/8&9/10,  C-9=B-11/12,  C-10=B-13/14&15/16,     
C-11=B17/18&19/20, C-12=B-21/22, C-13=B-23/24

6.6.8 SALIENT FEATURES OF KILNS (IP):


SALIENT FEATURES OF KILNS (IP)

OTK
SHUTTLE                 
NO. OF KILN
 01      
01
TOTAL LENGTH OF THE KILN        
 120
7200MM
WIDTH OF  KILN                                
1575MM
6100MM
HEIGHT OF CAR  AT ARCH                
2900MM
5000MM
HEIGHT OF KILN AT CORNER             
2700MM
3270MM
LOADING SYSTEM
Six Deck        
4to8deck
PRODUCTS
DISC UP TO210KN          
SOLID CORE& HOLLOW BUSSING UP TO 33 KV        
KILN CYCLE
58 Minutes/ Car             
120 to150 Hr
%  KILN RECOVERY
93%

LOADING/ UNLOADING                            
08Hr   
32 TO 40 Hr
FUEL CONSUMPTION
380L/ TON
7000L./ CYCLE
TEMPERATURE CYCLE  
    SOAKING
    OXIDATION
    REDUCTION
    COOLING

01Hr
07Hr
10Hr
22Hr
             
01 TO 04 hr                                 47 TO52  Hrs
18 TO 25 Hrs
55 TO 60 Hrs


WAITING TIME OF GREEN
16 Hrs
 72 Hrs

Max loading to the kiln
20 TON/DAY
72 Hrs
POWERR CONSUMPTION       
1000 Unit/ Shift
4600 Unit/Cycle
Table 6.4: Salient features of kilns (ip):

There is frequency of charging of wagon is 58 minutes. All the data are monitoring by a digital monitoring system in kiln control room.

6.7 OPERATION OF TUNNEL KILN:

6.7.1 CHECKING OF THERMOCOUPLE:

6.7.2 OBJETIVE:

Thermocouples are used to know the temperature of the medium in the kiln at different position. The thermocouple which are using in the kiln at high temperature will be spoiled after some period. Therefore it is necessary to check them to understand the exact temperature in the kiln.

6.7.3 TIME OF CHECKING:
1. Thermocouple where the temperature (t=1200 0r more) should be checked regularly once in three months.
2. Where (1100): Checked one in 6 months.
3. Where (t<1100): Checks once in one year.

6.7.4 CHECKING METHOD:
       I.            Fix the standard new thermocouple at crown couple no.15 i.e. in the cooling zone of OTK, because there is not much variation of temp. with time.

    II.            Now record the temp. For a few minutes first and then replace the couple with new one which we have to check and record for a few minutes.

 III.            Now find out the difference of temperature on the chart. Similarly all the thermocouple checked at the same position and records.

 IV.            Now difference of the standard couple with checking couple indicate on the chart.

IF:
 1. Couple indicates more than 10 ºC then couple should be used after revering the joint.
2. Couple are showing more than 20 oc then should not be used any place.

NOTE: Recorder should also be checked once in a year by the mill voltmeter.

6.7.5 ORIFICE METER FOR OTK BURNERS:
1. Orifice meter should be fixed to the each burner to improve the adjustment of air consumption.
2. It is used to adjust the diameter of the air nozzle.
6.8  PRE-HEATING ZONE TEMPERATURE IN OTK:
To avoid the ‘Baku’ defect in the article due to low temp. in the preheating zone and at the same time to save gas consumption, the standard temp. in the preheating zone should be maintain.
Bottom temp. of the wagon has lower temp. as compared to middle and top portions. Therefore, when thick article is loaded in the bottom portion then it might be develop Baku defect in the articles. Recirculation fans are used to mix the gases at top and bottom in pre-heating zone and hence reduce the temperature difference b/w the top and bottom. Actually these fans suck the heat from heating zone and exhaust in the pre-heating zone before exhaust to environment.

NOTE:
Standard temperature might be change according to the change of the body before get exhaust through exhaust fan.

6.6.1 TEMPERATURE OF OXIDISING ZONE:
Temperature of oxidizing zone should be fixed depending on the following factors.
1. Thickness of the articles.
2. Fineness of the grains of the body mass.
3.  Material components of the body mass.
4. Amount of loaded articles.
5. Method of loading
6. Scheduled of the wagon charging.
Considering the above factors, heat curve of the oxidizing zone is decided economically.

6.9 ACTION SHOULD BE TAKEN IN ORDER TO MAINTAIN THE:

6.9.1 BURNER’S TEMPERATURES ARE AS BELOW:
1. Checking of test pieces (sintering test).
2. Checking of bending position through OTK.

6.9.2 TEMPERATURE OF REDUCING ZONE:
The standard temp. in reducing zone should be set within the specified range. these temperatures should be maintain to get good reducing effect in the body before melting the glaze and to get good heat effect before reaching the highest temperature.


NOTE: 1.
Adjustment of the temp. should be adjusting by a gas. Gas consumption should not be changed frequently.


NOTE: 2.
To avoid the discolor defect due to oxidizing flame partly, the flame condition should be checked at peep hole regularly.
NOTE: 3.
 The temperature at any pair of burners should be the same.

6.9.3 BURNER ADJUSTMENT B/W OXIDIZING ZONE AND REDUSING ZONE:
At the reducing firing method in the tunnel kiln, this operation should be done very carefully because wrong operation of this burner causes ‘buku’ defects.
1. The reducing flame coming out from reducing firing zone should not be entered in the oxidizing zone hence must be cut by the air supplied by the burners B-9 and B-10.
2. The top burner should supply more than double the volume of air the bottom burner supply because it is necessary to make the flame flow down by the pressure of top burner to avoid the ‘Buku’defect due to less O2 at top.
3. At the peep hole 7 and 8, if possible there should be no flame, if not, very little flame should be allowed.

6.9.4 IMPORTANT:

v  Till oxidizing, there should be no flame if there is little flame then flame color should be bluish as in this zone volume of the air required is more (air: gas volume ratio is 20:1).
v  Till reducing, flame color should be yellow as in this zone volume of the air required is less (air: gas volume ratio is 10:1).
v  Composition of air and gas should be such that there should not be access gas in the flame otherwise smoke will come.

6.10 CONTROL OF SAND SEAL SAND:
“Sand in the sand-seal should be maintain to the correct level because it is used to prevent the hot gases flowing to the under car.”Always constant check should be made to see that correct level of sand is maintained in sand-seal.

v  If more sand is fed then sand will overflow and this way lifts the wagon and the wagon may de-rail.
v  If low level is maintain then hot gases may pass to the under car and cause damage to the ball bearings of the car wheels.
                                                             OR
Cooling air from under car pass to the kiln and cause oxidizing at bottom row of the wagon and the article will be discolored according to the pressure kiln and under car.

NOTE: -
The size of the quartz sand grains for sand seal should be b/w 3mm to 1.2mm.
6.10.1 ‘CO’ CONTIN IN REDUCING FLAME:
The maintenance of suitable CO contain is very important in the reducing flame because if CO contain is not maintained then following defects in the articles will be happens.
v  Body bubble due to insufficient reducing reaction.
v  Glaze bubble due to presence of much free carbon.

6.11 METHOD OF MEASUREMENT:

6.11.1 CO ANALYSER:
It measures the percentage of CO contained in the reducing flame in the reducing zone through peep holes. In OTK there are two positions where it must be checked, first position is at the starting of the reducing zone and second is at last stage of reducing zone.

v  If % of CO value is less than the standard value then gas should be increased.
v  If % of CO value is greater than the standard value then gas should be decreased.

6.11.2 BUKU SAMPLE FOR OTK:
Buku samples should be loaded and fired alone with articles. Buku defects is not visible from outside the sample hence it should be broken after firing and checked to understand the conditions of articles fired.

6.12 HOW TO AVOID:
This can be avoided by complete oxidation in pre-heating zone and oxidizing zone.

6.12.1 OPERATION OF RELIEF PORT IN OTK:

(A) RELIEF PORT BRICKS:
RP1&RP2, RP3&RP4, RP5&RP6 are to be closed completely by bricks.RP7&RP8 are to be half opened and air volume removing from inside of  the kiln will be adjusted by the changing of the gap.

(B) RELIEF PORT DRAFT:
The relief port draft checking at the waste heat duct (before fan) should be adjusted -11mm of water tube.

(C) RELIEF PORT DOOR:
The door should be open 25mm usual. But this can be opened up to 50mm to adjust the waste heat fan temp. less than 300oC.

6.12.2 OPERATION OF UNDER CAR COOLING:
This operation is done by: -
v  Main damper of cooling.
v  Under car exhaust fan.
v  Blowing and inducing dampers located at the sides of the kiln.
Pressure of the under car should be adjusted according to the kiln pressure. Special care should be taken to adjust the pressure at the beginning and middle of the reducing zone otherwise the cooling air will pass to the kiln through the sand seal and cause discolor of wagon at the bottom rows.

6.12.3 OPERATION OF THE MAIN DAMPER:
v  Volume of the air to under car is done by the adjustment of main damper.
v  Pressure is maintain by the adjustment of the under car fan.
v  Damper adjustment may be made according to the kiln condition.

NOTE: -
Operation of the sides dampers are made according to the pressure and volume of air required at the different places.

6.12.4 NEUTRAL:
 Maintain required temperature by operating LOV. Don’t operate combustion air flow.
Note: - This is the state where articles get matured.

6.13 CAR SCHEDULE IN OTK DURING POWER FAILURE TIME:
During power failure time when the plant is switched off there is every possibility of various defects such as:
v  Buku
v  Jiwa
v  Discolor
v  Porosity
Hence in order to minimize the above trouble we have to adjust the car operation as follows.

6.13.1 IF POWER FAILURE TIME IS WITHIN 5 MINUTES:
Car schedule should be changed by adding the actual period of power failure time (only for one car).

6.13.2 IF POWER FAILURE TIME IS LESS THAN 10 MINUTES:
This will affect the article in reducing zone. Hence after resuming of the power the first wagon should be pushed by adding actual power failure period plus 3 or 4 minutes and the next wagon should be pushed at std. scheduled time plus 3 or 4 minutes and from 3rd wagon std. time may be followed.


6.13.3 IF POWER FAILURE TIME IS LESS THAN 15 MINUTES:
The wagon pushing and neutral zone temperature adjustment may be followed as per 10 minutes shut down time and the std. time of schedule may be done from 4th wagon instead of 3rd wagon.

6.13.2 IF POWER FAILURE TIME IS LESS THAN 30 MINUTES:
The wagon pushing and neutral zone temp. adjustment may be follow as per 15 minutes shut down and the std. time of scheduled may be done from 5th wagon instead of 4th wagon.

6.14 SAGER CONE CHECKING:

(a) OBJECTIVE: -
This is used in the kiln wagons to maintain uniform firing and also to check the maximum temperature of article fired. It consists of different types of color with different numbers of pyrometric cones, such as 10, 11, and 12. Higher the no. value means higher the bending temperature of the cone. Hence we can say that at the same temperature the bending positions of the different numbers of the cone definitely will be different.


























7 .TYPES OF DEFECTS WHICH MAY OCCUR DURING FIRING OF THE SELL:
v  Black Spot
v  Pin Hole
v  Bukku
v  Discolor
v  Jeewa
v  Color Defect
v  Sand Spurting

7.1 BLACK SPOT (IRON SPOT): -
It is also known as iron spot because this affect occurred inside or on the surface of the sell only due to the presence of iron particles.

7.1.1 REASONS:
it may happened due to following reasons –

(a)DUE TO SLIP HOUSE:
If the iron particles present in slurry (In slip house) not removed through magnatoscreening then it appeared into the body and make a spot during firing.

(b)DUE TO GLAZING:
 At the time of glazing when sells are smoothen through iron equipment before applying glaze then some iron get entered into the body and cause a spot during firing.
(c) DUE TO LOADING :
Wagon are made up of iron material, if there is any crush in the wagon then iron particles may come on the surface of the sell and make a spot during firing.

(d) DUE TO OUTSIDE AIR:
 Iron particles may come on the surface of the sell from outside and may cause black spot during firing.

7.1.2 AFFECT:
There is no affect of the black spot on both electrical and mechanical strength of the sell.
Sell is rejected only due to bad appearance.

 7.2 PIN HOLE: (HAPPENED IN THE PRE-HEATING ZONE):
It happened in the pre-heating zone when entrap gases comes out through the surface of the sell body after melting of the glaze. It forms tiny holes on the surface of the sell. It may also be happened when some dust particles found on the surface of the sell at the time of glazing burn out in pre-heating zone.

7.3 BUKKU: (HAPPENED IN THE OXIDIZING ZONE): REASONS FOR BUKU DEFECT:

v  It happened when organic sample present in the sell do not completely burns inside the body. It happened also when the gases coming from the body do not completely escape from the body.
v  It happened in the oxidizing zone when 02 value is so high that it cool the surface of  the sell such as surface becomes sintered and prevent to incoming gases to overcome to the body of the sell.
v  After outside surface of the insulator is sintered, these gases remain inside and according to gas pressure insulator bulges and give the buku defects.
v  Buku defect will arise sometimes due to less temperature (mainly at bottom) and due to less of O2 gas (mainly at the top of the kiln).

7.4 DISCOLOR: (HAPPENED IN THE REDUCING ZONE):
A sell comes under the category of discolor when some part of the sell could not get the actual gray color i.e. body gets two different colors. It can be avoided by controlling the gas composition. If CO is less then increased gas & if CO is more then decreased the gas.

 7.4.1 REASONS:
Discolor happened only due to insufficient CO value present in the reducing zone.
Consider the following reducing zone reaction: -
          Fe2O3+CO = FeO +CO2
          CO2 + CO2 = 2CO
          Fe2O3+ CO = FeO + CO2
From above reaction it is clear that if there will be less value of CO then some part of the sell will be converted in the gray colored (FeO)completely but some part will not be Completely converted.
            So if there is less CO then we must be control it only by increasing the gas and the environment of kiln in this zone should be Smokey. Percentage of CO should be checked at the peep hole just starting of the reducing zone and at the last peep hole of this zone. Percentage of CO should be found b/w 3% to 9%.

7.5 JEEWA: (HAPPENED IN THE REDUCING ZONE):
If there is access of CO percentage in the reducing flame then kiln environment will be highly smoking then the CO2 gas which is comes out during firing hardly to comes out due to presence of CO and results is come in the form of jeewa on the surface of the insulator sell.  It can be controlled only by controlling i.e. reducing the value of gas in the flame.

7.6 COLOR DEFECT: - (HAPPENED IN THE NEUTRAL ZONE):
When sell reached to neutral zone then body of sell is sharp and gets maximum temperature i.e. 1285 0c.if at this temperature there is some smoky environment i.e. reddish flame then body gets absorb the carbon particle and produced color defects. So, to prevent the color defect we have to eliminate the CO atmosphere in this region.

7.7 SAND SPURTING :( HAPPENED B/W THE NEUTRAL ZONE (C13) AND C16 REGION):
 It appeared at the head of the sell when thermal expansion of the body of the sell does not match with the thermal expansion of the glaze in that region. Kiln temperature is always sated as per standard value of thermal expansion of the body so if there is any change has occurred in the composition of the body either due to alkali or any other thing then it comes in the form of this defect.
So to prevent this defect, if there is some change has occurred in the body composition then we should also have to change the kiln temperature in that region. The peak temperature can go up to 1280 ºC.

8. FIRING PROCESS:
Firing is actually verification of insulators, which causes the crystals to be combined with one another. In other words, firing can be termed as a process where compacted ceramic shapes are heated to a temperature where useful properties will be developed.

8.1 REACTIONS DURING FIRING:

8.1.1 LOSS OF PHYSICAL WATER:
 The physical water/moisture comes off as water vapor between 100 and 200°C.

8.1.2 OXIDATION (200-800 °C):
Here organic substances contained in the body are carbonized or combusted between 300 and 500 °C. The organic matter thus carbonized is subjected to oxidation from about 800°C and so called soot removal is carried out.

8.1.3 DECOMPOSITION:
Some compounds and their decomposition temperatures are as follows;

(a) HYDRATES                 Decompose between 100-1000°C giving off H2O.
(b) CARBONATES           Decompose between 400-1000°C giving off CO2.
(c) SULPHATES                Decompose between 1000-1200°C giving off SO2.

8.1.4 QUARTZ TRANSFORMATIONS:
Silica goes through various polymorphic transformations on heating mentioned as below;
v  Below 573°C – Alpha quartz
v  573-867°C     – Beta quartz
v  867-1470°C   – Tridymite
                             

8.1.5 COOLING:
v  After maximum temperature is reached, the vitrified body is subjected to cooling at a defined rate.
v  The key point in the cooling process is to cool glass inversion point of the cristobalite at about 573°C. When cooled below 600°C, beta quartz transforms abruptly back to alpha quartz with a sudden volume change.
v  So, slow cooling between 600-500°C is often required to prevent cracking.
Firing is the process where the insulators achieve the required end   characteristics of Electro-Mechanical (EMS), Bending & Hydraulic Strength.
It encompasses chemical & physical changes in the insulator body accompanied by a loss of porosity and a subsequent increase of density.

9. FITTING OF CERALIN IN METAL:
 


10. USES OF CERALIN:
Its superior wear resistance, chemically inert and high thermal stability characteristics make CERALIN suitable for a wide range of applications:

Power Sector         :   Wear prone components of Bowl / Tube Mill, Fuel Piping.
Steel Sector            :   Sinter Plants, Rotary Kiln, Coke Oven
Cement Sector       :   Cement & Raw Mills chutes & Air Separators
Coal Sector            :   Slurry Pipes, Chutes & Launders




11. CONCLUSION:
In the age high deficiency of energy we have to use the electrical energy in best manner. The electrical energy is very comfortable to use in daily life. This is the law nature that more reliable thing have more side effect. If make a small mistake in use of electrical energy, then it will become very dangerous . So we need insulator for the saving of electrical energy as well safety from electrical energy.
            The insulator is made of ceramic and porcelain. In BHEL INSULATOR PLANT JAGDISHPUR disc insulator, hollow bushing and ceralin is produced. The insulator disc is unit of string used as string.  
            The bushing is a hollow insulator, allowing a conductor to pass along its centre and connect at both ends to other equipment. Bushings are often made of wet-process fired porcelain, and may be coated with a semi-conducting glaze to assist in equalizing the electrical stress along the length of the bushing.
            Ceralin is manufactured using Calcined Alumina as a raw material. Spray dried powder is then compacted in Hydraulic Presses to form tiles. These tiles are then fired in a high temperature kilns at around 1560-1600oC to get required wear resistant characteristics. Ceralin tiles assembly to the casing is done by using Mortar, Silicone adhesives or Weld-on tiles.

4 comments:

  1. Ganeshmal: Exhaust Systems, Exhaust Manufacturing, Palvariser Manufacturer in India.


    For More Details visit http://tejtara.in/exaust_systems.php

    ReplyDelete
  2. what is the system of payment to suppliers??

    ReplyDelete
  3. Dolargroup is one of the leading company in Rotary Rack Ovens. Rotary Rack Oven very useful for those bakery industry whose production is medium or high. Because its very cost saving and time saving equipments for baking of cake, bread, cookies. This unit can bake the product uniformly because the trolley is rotate while hot air circulation will bake uniformly.

    For more details visit us:
    http://www.dolargroup.com/

    ReplyDelete