Power Sector Western Region

1. Power Sector Western Region Technology Day 11th May 2009

2. Power Sector Western Region TECHNOLOGICAL TOOLS

3. Power Sector Western Region Use of Electrical Torque wrench for Tightening Boiler Structure Bolts At 1 x 500 MW Khaperkheda

4. Cycle time reduction in tightening boiler structure bolts Background At boiler erection site thousands of BOLTED JOINTS are to be tightened MANUALLY using DE Spanners for snug tightening & Torque tightening by trip torque type long handle torque spanner. The process of bolting arrangement consumes enormous time for achieving desired results, including uniform tightening & ensuring a designed torque value. This process was identified for taking up Improvement project because of the following being repetitive in nature time consuming labour intensive having substantial amount of preparatory work to be done before the starting actual process (set up time) high level of risk involved (some locations for actual work place are above 80 meter above ground level & are to be performed on temporarily erected scaffoldings Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

5. Objective Reduction in time taken for complete bolting arrangement necessary for a 500 MW Boiler erection (at Khaperkheda site about 40, 000 no. M24 Bolts of lengths 70 – 160 mm are used) Ensuring designed tightness of bolting arrangement without further need of cross checking by Quality representative Safer working conditions for Operator Cycle time reduction in tightening boiler structure bolts Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

6. Evaluation of alternatives 1. Pneumatic torque wrench Benefits Available with leading hand tool manufacturers like Bosch, Ingersoll Rand & others. Widely used in manufacturing plants (automotive assembly lines) where high turnover per day is the hour of need (but here the Operator has a fixed place & jobs move to his operating area one after another). These wrenches are comparatively lighter. Drawbacks for us Difficulties in ensuring dry air to the wrench in all weather conditions Maintaining desired air pressure at a long distance through a compressor Requirement of supports since length of air pipes may extend up to 100 meters Thus making the whole arrangement very clumsy & big. Cycle time reduction in tightening boiler structure bolts Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

7. Evaluation of alternatives 2. Hydraulic torque wrench Benefits Available with leading hand tool manufacturers Widely used in manufacturing plants Drawbacks for us Need sophisticated hydraulic equipment (difficult to maintain) Require very good quality pressure hoses to feed optimum liquid pressure to the wrench limiting factors Practically impossible to provide such facilities at sites Cycle time reduction in tightening boiler structure bolts Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

8. Evaluation of alternatives 3. Electrically operated torque wrench Benefits Such wrenches are popular in assembly lines especially where job sizes are bigger & operator has to move around the job Available with leading hand tool manufacturers Electrical cables are much smaller, lighter & easily maneuverable Operate at 1 phase ac supply abundantly available at all areas of sites Cycle time reduction in tightening boiler structure bolts Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

9. Electrically operated torque wrench (contd..) Results of Field Trial M/s Tristar Industrial Tools Pvt limited was a source located for making a demo at Khaperkheda Trial was successfully done on 10th April 2009 at a height of about 10 meters on Column number 19. Time taken to fully tighten bolted joint by ETW was about 15 seconds as against 3 to 4 minutes by a handle type Trip Torque Wrench Substantial saving in operation time for the activity Saving in manual effort by Operator Positive assurance of Quality of bolted joint. Cycle time reduction in tightening boiler structure bolts Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

10. Electric wrench for tightening boiler structure bolts Technische Daten DEA – Technical data DEA PLARAD – GERMANY Make Technische Daten DEA – Technical data DEA Our selection Type DEA 12 TLX Torque 200 – 1220 NM Weight 6,8 kg Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

11. Electric wrench tightening of boiler structure bolts Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

12. Electric wrench tightening of boiler structure bolts Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

13. Expected Benefits   Tangible Saving in Time - On average saving of about 3 minutes per bolt Saving in manpower cost No need for Quality representative to ensure desired objective of proper tightness Additional helper to hold spanner and a trip torque wrench, not required. Intangible Safety of Operating Personnel (Operators & others assisting him) from any Accidental fall due to Slipping Slipping / Falling of the job from temporary scaffolding Better safety of personnel on ground from falling of long torque wrench etc. Cycle time reduction in tightening boiler structure bolts Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

14. Power Sector Western Region Measurement of Face Run- out of IP & LP Rotors by improvised technique at site

15. Measurement of Face Run- out of IP & LP Rotors Normal Practice Normal practice of measurement of face run-outs of IP & LP Turbine Rotors is To place them on saddle supports and rotate them (There is only an arc of contact between the saddle and the rotor). A pin is made and inserted in one of the coupling holes. A wire rope is wound around the rotor with the pin at one end and the crane hook of the EOT at the other. Lifting action of the crane hook causes rotation of the rotor. To aid in rotation of the rotor, copper sheets are placed in between the saddle and the rotor and, grease is smeared to reduce friction during rotation. Contd… Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

16. Measurement of Face Run- out of IP & LP Rotors Normal Practice (Contd..) The normal method has few problems associated with it It is not possible to restrict axial movement of the rotor in order to avoid overshooting the range of the dial gauge. Area of contact being very small, it requires extreme care and control while operating the EOT, lest it should cause an irreparable accident and lead to loss to both men and material. It has often been noticed that there is quite an error between the measurement made at shop and those made at site leading to avoidable loss of time in correspondence, summoning experts from MUs, etc. It gives the feeling of using a very primitive and un-reliable method of measurement. Overall, it is never like measuring the run-outs by anchoring the rotor on a lathe to take the measurements and that’s exactly the cause of the error. Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

17. Measurement of Face Run- out of IP & LP Rotors Suggested New Method A simple device is made at site using the following material Shaft of 40mm Ø x 1000mm long 1 no. Ball Bearings with Plummer block for above shaft 2 nos. Supports to anchor the Plummer blocks 2 nos. Cross arm 1 no. Dial Gauges for mounting to X-arm 2 nos. Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

18. Measurement of Face Run- out of IP & LP Rotors Brg with Plummer Block Dia 40 Shaft Cross Arm Dial Pointers External Support for anchoring the Plummer Block Shaft Support provided by Unit Fixture developed and used Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

19. Measurement of Face Run- out of IP & LP Rotors Advantages User friendly and costs only Rs.5000/- to make. Does not require too much of a precision in machining the shaft. Does away with repeated rotation of the rotor for every reading. Reduces the risk of the rotor toppling during rotation by EOT crane. Compares well with the values attained at works on a lathe. Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

20. Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA Trombay This was the 1st time the Generator Stator has been lifted by Strand Jack Method in PS-WR. Also, this is the 1st for 250MW Stators in the whole of BHEL. Picture shows Stator lifted off the Blocks.

21. Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA Trombay….Contd • Stator lifting in progress

22. Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA Trombay….Contd • Stator lifted and being moved inside the A-Row of TG Building

23. Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA Trombay….Contd • Stator lifted above the bottom of TG Deck and ready to be moved inside for placement.

24. Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA Trombay….Contd • Picture shows the Strand Jack Hydraulic Control System

25. Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA Trombay….Contd • Picture shows stator in position • The entire operation was completed in 4 hrs from the start.

26. Power Sector Western Region PORTABLE INDUCTION HEATING MACHINE

27. INDUCTION HEATING MACHINE Conventionally, we at BHEL Power Sector Sites have been using the Induction Heating Machines of EDN Bangalore make. There are certain disadvantages of using this equipment listed below: 1. Too bulky and comes in two parts – one the Induction Heating Equipment proper and the other, the operator’s panel. Weighs a few tonnes. 2. Due to its bulk, moving the machine to different areas of work is an arduous task. Each shift of the machine is a 1 ½ days activity. 3. Often, it has been seen that when the machine is moved from one location to the other is has not been in use for a few months, the next re-start is faced with quite a few problems. The reason is not known. 4. Getting spares on time for the equipment is a big issue. This results in machines with minor repairs and requiring spares quarantined. 5. Overall the machine is not user-friendly 6. Costs around Rs. 75 Lakhs per machine Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

28. Induction Heating Machine -….Contd Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

29. Induction Heating Machine -….Contd Alternatively, there are machines available in the market and being used by our competitors that is a vast improvement on the EDN Make machine and has the following advantages: 1. Very small and easily portable, thus rendering easy movement of the machines to various locations without loss of vital erection cycle time. Requires only a 2-3 hrs for shifting and re-connecting. The entire machine is as compact as welding transformer and is single modular. Weighs approx. 105Kgs. 2. The connections are very simple and does not need expertise. 3. Though imported, has a presence in the Indian market for the last 3 years and has been used to weld pipes of 94mm thick at Sipat. The machine can be used to thicknesses in excess of 100mm pipes as well. The size of MS Pipe for the proposed 660MW Unit with Full Flow is Φ660 x 102mm. 4. Costs only Rs.30 Lakhs. For every one machine of EDN Make, one can two of this kind. Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

30. Induction Heating Machine -….Contd Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

31. Induction Heating Machine -….Contd Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

32. Power Sector Western Region Induction Heating for Opening & Tightening Casing fasteners of Steam Turbine

33. Induction Heating for opening & tightening Casing of Steam Turbine Introduction Casing of steam turbines are tightened together by using threaded fasteners of M48 to M140 size . These fasteners referred commonly as studs and cap nuts have to be tightened firmly to withstand the high internal pressure and temperature. During the tightening process, specified value of elongation has to be achieved so that during working at high temperature, the nuts will not slacken . A recommended practice for tightening these fasteners is heat tightening. Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

34. Induction Heating for opening & tightening Casing of Steam Turbine Commonly used devices for heating the fasteners Electric heaters - which include heater elements, cables, power source /transformer of high capacity etc. Gas heaters. This is relatively simpler method which uses the specially fabricated bolt heating devices - Gas Torches with special nozzles, and oxy-acetylene cylinders , compressed air supply etc. Main disadvantages of the above two methods Long time taken for the operation Due to the slower rate of heating, effectiveness of these methods is less and some other problems such as seizure of the threads also occur quite frequently. Apart from this, the arrangements required are also complex and time wasted in maintenance / repairs of the equipment in case of defects is quite considerable. Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

35. Induction Heating for opening & tightening Casing of Steam Turbine Induction heating method for threaded fasteners Induction heating method is being used in other site applications such as preheating of joints for special welding of alloy steel pipe lines in thermal power stations. This method is very quick and effective means for heating. By using some modified gadgets, it was found suitable for loosening and tightening of the big size threaded fasteners of steam turbines, valves etc. SAS Nagpur decided to use the induction heating method for loosening and tightening of threaded fasteners. This method has resulted in saving valuable time for dismantling and assembly of steam turbines during overhauls. The method is simple and highly effective. With the use of induction heating method, the problem of seizure of threads necessitating cutting and gouging of the nuts and studs, in LMW design, has been minimized. Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

36. Induction Heating for opening & tightening Casing of Steam Turbine Comparison of time required for bolt opening • Time saved for overhauling is 3 days . • For a 210 MW set this translates into a gain of 5.04 million units perday i.e approx. Rs. 2 crore per day • For 500 mw set, 12 million units per day i.e.approx. Rs.4.8 crore perday Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

37. LASER ALIGNMENT KIT OBJECTIVE • To carry out various alignment works in Turbine erection • With high precision. • At a reduced cycle time. WORKS CARRIED OUT • Catenary of pedestals • Centering of bores of Diaphragms, Pedestals, Shaft Seals etc. • Alignment of Rotors. CATENARY OF PEDESTALS • Accuracy of 10 Microns achievable. • Source equipments to be placed at extreme pedestals. • Mobile equipment placed in intermediate pedestals. • Laser is passed thro mobile equipment and adjustments carried out as per requirement. Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

38. LASER ALIGNMENT KIT Centering of Bores of diaphragms,pedestals,shaft seals etc • Source Laser device fixed in one extreme end pedestal • Receiver end device fixed in other extreme pedestal. • Special fixtures used for centering of intermediate pedestals. • Online adjustment possible. Alignment of Rotors • Can cater to Coupling Dia from 100 mm to 1200 mm. • Alignment Device fixed on couplings to be aligned • Total misalignment is indicated by just 60 degree rotation of Rotors. • Misalignment values as well as correction required indicated in display. Salient Advantages • Saving in Cycle time. • Accuracy of Measurement. • Indication of correction factors. Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

39. LASER ALIGNMENT KIT CONCLUSION • The Laser Alignment kit is a useful equipment that is State of the Art in Technology and can be used very effectively in Turbine activities at high precision and reduced cycle time, as has been proved in Kudankulam site. • Hence extensive use of this equipment has to be practiced. Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

40. ORBITAL WELDING • Purpose – To provide leak proof joint between Tube to tube sheet in Condenser in addition to Forced expansion • Process – GTAW without filler wire addition • SIGNIFICANT ASPECTS • Material-Titanium • Large Qty of welding • Welding in position & at site • Materialsupply by Russians • TITANIUM TUBES • Grade : ASTM B 338 Gr2 • Tube Sheet : 35 + 5 mm thick • Material : ASTM A516Gr 70 + ASTM B 265 Gr 1 CLAD Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

41. ORBITAL WELDING • Why Titanium is used? • Provides excellent resistance to general and localized attack under most oxidizing, neutral and inhibited reducing conditions in aqueous environments. • Corrosion Resistance due to stable, protective strongly adherent oxide film which forms instantly when a fresh surface is exposed to air moisture. • This film is transparent and not deducted by visual means. • Titanium resist corrosion by sea water to temperature as high as 260 0 C. • Even exposed to sea water for many years at a depth of over a mile shows no measurable corrosion. • Provides over 25 years of trouble free sea water service for chemical refinery de-salination and nuclear industries Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

42. ORBITAL WELDING • Has the ability to resist erosion by high velocity sea water • The presence of abrasive particles such as sand has only a small effect on the corrosion resistance of Titanium • Production began in the late 1950s • Most widely used titanium is commercial pure (99.5 % Ti) • Manufacturing Process • Ingot →slab → Hot strip → cold strip → Slitting → Forming → TIG Welding → Stress relieving → Eddy Current & Ultrasonic testing Exploring Heights ..................... Setting Standards .................... Marching Towards Excellence Power Sector Western Region

43. ORBITAL WELDING Physical Testing Tensile, flare, flattening & reverse flattening Visual Inspection Cleanliness, ID, OD, Surface condition, end condition and marking. Tube to tube sheet joining Contact Rolling (0 to 5 % wall thinning for a length of 10 mm) Orbital Welding – For highly reliable leak tightness Forced Rolling (8 to 10 % wall thinning for a length of 25mm)

44. PROCESS FLOW CHART Sh 1 of 3 Front / Rear end tube sheet cleaning – wire brush mounted in portable drilling machine followed by acetone Visual inspection Titanium tube insertion Initial cleaning before contact rolling Initial contact rolling up to 10mm

45. PROCESS FLOW CHART CONTD… Sh 2 of 3 End facing of tube & tube sheet up to 0.05 mm Welding Excess length trimming in the rear side Visual inspection Rectification of repair work Final expansion 8 to 10 % by lubricating SAE 40 oil

46. PROCESS FLOW CHART CONTD… Sh 3 of 3 Final cleaning by acetone Dye Penetrant testing Tube tightness test by MAUS Gun G-150

47. TUBESPECIFICATION

48. TUBE INSERTION AT KODAMKULAM

49. PROGRAMABLE ORBITAL WELDING MACHINES FRONIUS MODEL - FPA 2000 (AUSTRIAN MAKE)

50. AFTERTUBE INSERTION