Control valve maintenance process
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7.1 Control Valve Overview and Parameters 7.1.1 Control Valve Overview Taipower control valve mainly cops and fisher two specifications, mainly used in the superheater I, II temperature control left and right side of the regulating valve (a total of 4, size 2.5 " ANS1 CL.2500) Reheater temperature reduction Left and right control valves (4 in total, size 4 "ANS1 CL.1690). Reheater Accident Spray water left and right side control valve (each one, size 1.5 "ANS1 CL.900) 7.1.2 Main performance parameters of the control valve 7.1.2.1 Superheater II-stage temperature reducing right control valve is 1.5" ~ 2.5 "ANS1 CL.2500; use stainless steel wound pad Size: 82.5 * 71 * 4.5mm (2), 106 * 90 * 4.5mm Up and down braided packing: 32 * 19mm Intermediate graphite molding ring: 32 * 19mm 7.2 Regulating valve 7.2.1 Preparedness 7.2.1.1 Preparation 7.2.1.1.1 Make sure there is no pressure on the medium in the valve cavity and the pipe connected to it. 7.2.1.1.2 Preparation Good place to disassemble the valve to prevent damage to the parts when stacked 7.2.1.1.3 Prepare the necessary mapping equipment 7.2.2 Control valve repair steps, process 7.2.2.2 squirrel-cage adjustment door disintegration inspection 7.2.2.2.1 Manually open the valve 2-2 ring. Unscrew the electric head fixing nut and remove the electric head. 7.2.2.2.2 Loosen the upper cover nut of the valve, remove the upper cover, and remove the upper cover and the body sealing toothed pad. .2.2.3 Unscrew the seat sleeve for inspection 7.2.2.2.4 Loosen the packing gland tightening nut and remove the pointer Remove the pointer with the handle, and remove and remove the stem from the copper cylinder with a handle. 7.2.2.2.5 Remove the stem and copper frame and the frame, connect the semi-circular retaining ring outer ring and remove the semi-circular retaining ring , Remove the cupper, bearings and washers from the frame 7.2.2.2.6 Loosen the stem and plug sleeve to secure the plug and unscrew the plug sleeve 7.2.2.3 Squirrel-Cage Adjusting Door Maintenance 7.2. 2.3.1 Check the valve body seat, sleeve seat without shaking off phenomenon, and the valve body is fixed well. 7.2.2.3.2 No cracks and other defects in the valve body, the entrances and exits unobstructed. 7.2.2.3.3 clean packing pan packing, And the packing ring polished. 7.2.2.3.4 Check the plane bearings, ball and rack with a good fit, no shedding, or should be replaced. 7.2.2.3.5 Stem stem thread trapezoidal intact, no broken buckle, bite Buckle now 7.2.2.3.6 Stem trapezoidal thread intact, curvature and ovality meet the requirements. Surface smooth, non-corrosive. 7.2.2.3.7 Valve sleeve and seat sleeve sealing surface with good, no groove, etc. Defects, sleeve hole intact, no erosion throughout the phenomenon. Sleeve with flexible without jam. 7.2.2.3.8 Check the Department of the fastening screw , Nuts intact. Thread without breaking buckle, bite buckle phenomenon, hand-screwed nut can be screwed to the bottom of the bolt, the assembly should be coated with graphite powder. 7.2.2.3.9 Valve body and bonnet junction sealing surface should be smooth, 7.2.2.4 Squirrel Cage Regulating Door Assembly 7.2.2.4.1 Screw the seat sleeve onto the sleeve inside the valve body and fasten it. 7.2.2.4.2 Tighten the stem and disc sleeve and tighten with fixing screws. 7.2.2.4.3 The copper mother and bearings, gaskets assembled in order, placed in the upper shell of the frame, with a fixed half-ring stuck, half-ring jacket good retaining ring. 7.2.2.4.4 Insert the stem into the bonnet and onto the stem copper nut. At the same time pay attention to the packing seat, packing gland, scale pointer synchronization installed. 7.2.2.4.5 Place a toothed pad between the bonnet and the sealing surface of the valve body, assemble the valve bonnet and the valve body, fasten the bolts and nuts, and then tighten them symmetrically, with even tightening force and proper clearance. 7.2.2.4.6 Fill the packing chamber as required, top with packing gland pressure, tighten the fastening bolts. 7.2.2.4.7 Install the key to the copper mother, the electric device is installed, tighten the fastening bolts. Manually switch the valve, check no problem, the valve rocked to the fully closed state. 7.2.2.5 Bezel-type regulating valve 7.2.2.5.1 Unscrew the electric head set screw and remove the electric head. 7.2.2.5.2 Remove the valve frame and the valve body fixing nut, remove the self-sealing, and then rotate the stem copper nut anticlockwise to disengage the frame from the door lever. For double-valve stem valve should first remove the pointer, with the hand moving the home pole, so that the upper and lower pole from, and then remove the frame. 7.2.2.5.3 Remove the upper bearing chamber lock nut fixing screws in the frame and unscrew the lock cylinder to remove the bearing and spring washer from the frame. 7.2.2.5.4 Remove the packing gland nut and remove the packing gland and pressure plate. 7.2.2.5.5 Remove the six-ring outer ring. 7.2.2.5.6 With the tool will be self-sealing valve cover pressed so that the valve cover and the gap between the six and the ring, and then split off the six-ring. 7.2.2.5.7 Use the lifting tool to lift the valve stem together with the valve cover and valve stem. 5.8 Check the valve seat wear, cover the valve cover with a seal. 7.2.2.5.8 Remove the stem from the bonnet. Save the removed parts. 7.2.2.6 baffle-type control valve inspection 7.2.2.6.1 check the valve seat outlet eye wear and tear, do a good job of maintenance records, clean the surface, hole smooth, check the weld intact orifice plate burrs can be polished with Whetstone . 7.2.2.6.2 Check the valve disc baffle sealing surface, the general defects available buff stone. After deep trench welding, should be processed to restore the original size. For baffle throttle on the control valve, check whether the erosion of the throttle damage, the bottom of the through-hole is over the deformation. 7.2.2.6.3 Baffle side grooves and valve body rail should be smooth, solid integrity, no jamming phenomenon, or should be repaired. 7.2.2.6.4 Check the baffle and the stem connection groove cracks and damage, if necessary, testing inspection. 7.2.2.6.5 packing seal replacement 7.2.2.6.5.1 bonnet seal packing packing should be cleaned, self-sealing packing pressure ring to remove rust, and polished clean pressure ring into the valve cover, sealing boss clearance should meet the requirements . 7.2.2.6.5.2 Stem sealing Packing room should be cleaned, the inner wall polished clean, gland packing and pressure plate should be removed rust, surface cleaning, gland bore and stem clearance should meet the requirements. Otherwise it should be repaired. 7.2.2.6.5.3 loosen hinge bolts, check the threaded part should be intact, the nut intact, can be hand-screwed to the root of the bolt, the pin rotation flexible. 7.2.2.6.6 Stem 7.2.2.6.6.1 Check whether the valve stem curvature meets the requirements, if its curvature is greater than the specified standard, it should be calibrated or replaced. 7.2.2.6.6.2 clean the stem surface rust, check the surface corrosion is greater than the required standard. 7.2.2.6.6.3 The stem and gate assembly, should be flexible, no jamming. Downward movement of the circular convex surface should contact the shoulder without force. 7.2.2.6.7 Stem Nut 7.2.2.6.7.1 Check the inner thread of the stem nut of the stem nut is intact, and there should be no phenomenon such as twisting and buckle. Otherwise, replace it. 7.2.2.6.7.2 The bearings and bushings with kerosene to clean, check the bearings should be no rust, cracks and other defects, rotation without abnormal sound, defects should be repaired or replaced. 7.2.2.6.7.3 Inspect and clean disc springs, which are found to be cracked or markedly deformed and should be replaced. 7.2.2.6.7.4 Check the stem copper nut intact and outer sleeve fixing screws complete, no loosening after closure. 7.2.2.6.8 double valve stem valve should be checked, the lower end of the stem thread connection should be intact, defective or promptly dealt with or replaced. 7.2.2.7 baffle-type control valve assembly 7.2.2.7.1 with a valve rod hanging baffle, along the track into the valve body, pay attention to measure the baffle and valve seat, body track and bezel gap, and make a record . 7.2.2.7.2 The self-sealing valve cover into the valve stem, into the valve body, fill the self-sealing packing as required, and finally pressed with packing pressure. 7.2.2.7.3 turn the hexagonal ring in turn, the valve cover lifting bolt onto the valve cover. 7.2.2.7.4 Filling the packing as required to the valve rod packing chamber, the upper packing gland pressure is good, the bolts tightened. 7.2.2.7.5 The stem nut and internal parts installed in the bearing chamber, the bearing should be coated with butter, disc spring loaded as required, and finally lock with the lock, with a fixed screw off. 7.2.2.7.6 Lifting the frame to the valve stem with the lifting tool, turn the valve stem nut so that the frame falls on the valve body and tighten with the bolt and nut. Double valve stems, while the frame is installed, while simultaneously rotating the home pole and door stem nut, so that the upper and lower door stem threaded connection, and then use the hand to make the upper and lower door rod firmly connected. 7.2.2.7.7 Reassemble the stem travel indicator clamp, tighten the bolts, the indicating plate should be affixed to the valve frame has a machining plane side. 7.2.2.7.8 with the valve motor installed complex, solid bolt. 7.2.2.7.9 manually switch the valve, the test is flexible. 7.2.2.8 rotary control valve 7.2.2.8.1 The valve handle and the transmission rod disintegration, the connection pin is saved. 7.2.2.8.2 Unscrew the valve stem front end stop nut, remove the lever, release the handle fastening nut, remove the handle. Loosen the packing gland nut and remove the gland. 7.2.2.8.3 Remove the stem rod stopper bolt and save it. 7.2.2.8.4 Loosen the bonnet tightening nut, hang the lifting tool on the bonnet, lift the bonnet firmly, loosen all the nuts, and lift the bonnet off the valve body. 7.2.2.8.5 Pull the valve body out of the valve body and make the switch mark on the end surface of the valve shaft to prepare for complex installation. 7.2.2.9 Rotary control valve inspection 7.2.2.9.1 Check the valve seat and the valve sealing surface with or without grooves, scratches. 7.2.2.9.2 with sandpaper to clean the surface of the valve flaws pull marks, test and check valve seat clearance, the larger defects should be cleaned or replaced. 7.2.2.9.3 Check the valve cover to clear the liner, and the door joint surface should be cleaned and found defects should be scratched and leveling. To meet the quality standards. Clean up all the fastening bolts, repair the threaded parts, so that bolts, nuts with flexible, and coated with lead powder preserved. 7.2.2.9.5 The valve cover stuffing box to clean, remove the old packing, the cabinet wall clean with emery cloth. 7.2.2.9.6 The packing seat, packing gland surface rust polished. 7.2.2.9.7 Check the valve plug and stem firmly connected. 7.2.2.9.8 The transmission links shall be intact and the transmission shall be reliable. The joint pin should be flexible without jam, the surface should be polished clean, and coated with a small amount of grease for lubrication. 7.2.2.10 Rotary control valve assembly 7.2.2.10.1 Check the valve body no foreign body, and clean the interior. 7.2.2.10.2 After wiping the valve disc, install it in the valve body to test whether it is flexible. Align the valve window with the seat window and make the switch mark. 7.2.2.10.3 The valve cover all the bolts coated with lead powder, the bonnet joint surface into the asbestos pad coated with graphite powder, the valve cover lifting, and tighten the fixing nut, fastening method should be used symmetrically , Pay attention to ensure that the gap around the valve cover evenly. 7.2.2.10.4 Fill the packing ring, add the packing as required. Packing gland should be compressed. 7.2.2.10.5 Reinstall the shaft end handle and connecting rod components, adjust the opening degree. 7.2.2.10.6 The front bar of the door rod should be installed horizontally, and the bolts and nuts should be fastened well. 7.2.2.10.7 tidy up the inspection records and various sizes, the site clean up, the equipment hang cards. 7.2.2.11 After the valve overhaul, clean the scene, the device hang good signs. 7.2.2.11.1 The operating personnel shall check the civilized environment of the equipment and after repair, the equipment shall be of true color, heat preservation and good paint, and both parties shall conclude their work tickets. 7.2.2.11.2 valve tightness test can be carried out with the furnace pressure, check the valve opening is normal, packing leaks, no problem, the valve tightness qualified. 7.2.2.12 Pneumatic control valve overhaul 7.2.2.12.1 The thermal control valve pneumatic device removed. 7.2.2.12.2 Bolt nut with upper packing gland Loosen the gland with the wrench. 7.2.2.12.3 unscrew the nut on the stem connected to the stem. 7.2.2.12.4 Loosen the bonnet nut. 7.2.2.12.5 Remove the valve pneumatic device. 7.2.2.12.6 Remove the bonnet together with the stem, unscrew the stem and remove the bonnet from the stem. Then hollow out the packing inside the valve cover. 7.2.2.12.7 Remove the cage and lower seat in the valve body. 7.2.2.12.8 Check the stem, spool, cage, seat wear, determine the method of repair, the valve cover with a good cover. 7.2.2.12.9 Check the valve body for foreign matter, corrosion, erosion and cracks. 7.2.2.12.10 Disintegration is completed. 7.2.2.12.11 valve inspection and repair. 7.2.2.12.12 Check the body for blisters, cracks and erosion, etc., if there should be digging or replacement of the new door. 7.2.2.12.13 Inspect the valve body. , The valve seat weld cracks, trachoma and other defects. 7.2.2.12.14 Check the valve disc and seat sealing surface for serious erosion, wear and tear, the phenomenon of minor wear can be polished with emery cloth, serious valve or valve should be replaced to check the valve flap and seat seal Face combination. 7.2.2.12.15 Change the valve flap when measuring the clearance between the valve flap and the sleeve. 7.2.2.12.16 rust parts, replacement packing and sealing gasket. 7.2.2.12.17 measure the size of the filling room, stem, gland, seat and other parts with each other. 7.2.2.12.18 The screws of each department shall be defect-free and flexible to rotate. 7.2.2.12.19 The stem shall not be bent, if it is found that bending should be straightened or replaced. 7.2.2.12.20 Stem surface should be smooth without scratches, grooves and corrosion phenomena, found that timely treatment. 7.2.2.12.21 Check whether the plate deformation, cracks and other defects, repair defects found in a timely manner, or replaced. 7.2.2.12.22 valve repair is completed 7.2.2.12.23 valve assembly: 7.2.2.12.24 valve seat, cage, stem and gasket in turn into the valve body. 7.2.2.12.25 Slowly install the bonnet from the top of the stem and tighten the bonnet flange nut. Placed bottom pad, add packing. 7.2.2.12.26 Tightly lower flange bolts 7.2.2.12.27 Fill the packing well and tighten the lower packing gland. 7.2.2.12.28 To note: a All packing pressure, temperature should meet the media requirements. B packing specifications should be consistent with the requirements of sealing parts, packing height should be kept with a tight margin. C packing is best formed graphite packing ring. 7.2.2.12.29 Replace the Gland, tighten the packing bolts and lift the packing chamber evenly. 7.2.2.12.30 Packing gland should be kept flat and tightened uniformly. The inner hole of packing gland is consistent with the clearance around the valve stem. 7.2.2.12.31 Replace the pneumatic head, tighten the fastening nut. 7.2.2.12.32 Pneumatic head on the valve stem, fastening bolts. Adjust the opening pointer. 7.2.2.12.33 Reassemble thermal control device. Check the valve. 7.2.2.12.34 restore insulation, clean-up site. 7.2.2.12.35 boiler hydrostatic test 7.2.3 quality control valve overhaul 7.2.3.1 Stem curvature ≤ 0.05-0.10mm, and does not exceed the total length of the stem 1/1000, the depth of the stem corrosion pits ≤ 0.30mm . Ovality is not greater than 0.05mm. No damage to the bonnet bushing, wear and tear. Stuffing box wall, gland, seat cleaning no foreign body. 7.2.3.2 bonnet and self-sealing surface with a smooth, clean and no foreign matter. Granville plate no bending deformation. Check the valve seat, the spool has no cracks, trachoma, pitting, etc. and make a record. 7.2.3.3 Stem and gland, seat gap is 0.1 ~ 0.3mm, the maximum does not exceed 0.5mm. Gland packing, seat ring and packing room wall gap of 0.2 ~ 0.3mm, the maximum does not exceed 0.5mm. Bolt nut with or without buckle, bite buckle. 7.2.3.4 valve seat, the valve core to reveal the metallic luster, finish to meet the requirements, the bonding surface of 100% (valve line is a closed clear line). 7.2.3.5 There is no serious erosion, wear and tear on the sealing surface of the valve disc and valve seat. The sealing surface is in continuous contact with a uniform width. The thread of the valve stem should be intact, without any defects such as fracture and bite buckle. 7.2.3.6 Disc and sleeve clearance should be between 0.15 ~ 0.3mm 7.2.3.7 Stem surface contact with the packing shall not have sheet-like corrosion and surface delamination phenomenon, uniform corrosion depth of 0.25mm or more should be replaced. 7.2.3.8 platen intact without deformation. 7.2.3.9 gasket should be laid flat, the components should be noted that the direction of anyway. 7.2.3.10 Bolts shall be coated with molybdenum disulfide. Tighten the nut should be fastened, force should be uniform. Packing cut should be staggered 90 ° ~ 120 °. 7.2.3.11 Fillet incision into a bevel, the angle of 45 °, the interface without gaps. Gland packing room tight tight after no distortion, tightening force evenly. Seat should be intact, no rust scale, no deformation, no cracks, packing room wall cleaning 7.2.3.12 according to the reverse order of removal back. Bolts should be tightened evenly and the gland pressed into the gland 5mm. 7.2.3.13 consistent with the opening degree of the pointer, the valve switch trip without jam, no virtual journey and loose. 7.2.3.14 insulation integrity, the site has been cleaned. 7.2.3.15 Water pressure test No leakage, if leakage, can be tested after the water pressure, and then tighten the packing gland screws. 7.3 Safety, Health and Environmental Requirements 7.3.1 Safety 7.3.1.1 First check the safety measures and work flow in accordance with the requirements of safety regulations before starting work. 7.3.1.2 Before loosening the valve bolt, check that there is indeed no pressure in the pipe, check that the trap door is open and the water has been released. 7.3.1.3 During the inspection process, the hydrophobic door must be kept open until the valve does not leak out of the wound. 7.3.1.4 When loosening the bolts, care shall be taken to prevent possible injuries caused by the possible accumulation of steam or hot water. 7.3.1.5 After the valve is disassembled, clean the tools and the removed parts, and take protective measures on the dismantled valve to prevent foreign matter from falling in. 7.3.1.6 When working on soda pipe for a long time, the pipe section with tail shall be reliably cut off by the block pipe with tail in the overhaul section. 7.3.1.7 In the installation, the return pipe flange or valve, not allowed to use your fingers into the hole touch. To prevent finger injury. 7.3.1.8 Working at heights, wear safety helmets, wear protective clothing and work shoes, and take good care of them. Materials, spare parts, etc. should be placed in a solid and reliable place. 7.3.1.9 emergency elimination should be done to prevent the high temperature valve pipe burns safety measures, such as anti-hot work clothes, gloves, work shoes and so on. 7.3.1.10 Use of electric tools to pay attention to leakage, the risk of electric shock, the use of electric grinding, the risk of eye damage with iron filings; check the power tools to prevent leakage, the use of angle grinders and other power tools to wear protective eyes. 7.3.1.11 Replacing the valve During welding, prevent electric sparks from splashing in the cable tray causing a fire hazard. 7.3.2 Health 7.3.2.1 When working in the working environment with high temperature, take measures to prevent heatstroke. 7.3.2.2 on the workplace near the hot objects, to be well protected from contact with workers on the hot objects. 7.3.2.3 Do not use excessive force at work to prevent waist sprain. 7.3.2.4 Use dust masks or qualified masks when removing insulation from pipes or valves. 7.3.2.5 staff entering the pipeline or underground should rotate their work and rest. 7.3.3 Environment 7.3.3.1 Remove the parts to be neatly arranged. 7.3.3.2 Valve Tightness Test The used kerosene should be properly disposed of, and should not be directly poured into the garbage dump or sewer. 7.3.3.3 When carrying out the work of painting the pipe or valve, it is to prevent the paint from falling underground or flowing to other equipment. 7.3.3.4 After the work is over, clean the work site and ensure the workplace is clean and tidy. 7.3.3.5 work is completed, clean up the site, classified into the garbage dump. 7.4 After-service test items and standards 7.4.1 Equipment put into operation before the water pressure with the furnace. Check the packing roots have water seepage, the valve opens check the pipe outlet media out, no media after the closure of the phenomenon of drip, indicating that the valve sealing surface qualified, packing appropriate. 7.5 Maintenance category and overhaul cycle 7.5.1 Maintenance once a year, the size of a random set of equipment maintenance 7.6 Control valve maintenance 7.6.1 Maintenance in daily operation 7.6.1.1 Cruise inspection content 7.6.1.1.1 Visual boiler sealing surface No? B leakage, parts are damaged, visual ear to hear the implementation of institutions without leakage, the implementation of power with or without leakage. 7.6.1.2 Cruising Standard 7.6.1.2.1 Visual boiler valve sealing surface without? B leakage, parts without damage, visual ear to listen to the implementing agencies without leakage, the implementation of power without leakage. 7.7. Regular maintenance projects in operation, cycles and standard periodic maintenance projects