What are the measures how to safety maintenance pipeline, valve?

1, must be confirmed before repair the valve, the pipeline and system reliable isolation, the water valve, the pipeline system, after dropping to zero, can begin to repair. Cut pipe, the cut of the nozzle must block in time, to prevent falling into sundry. A groove, workers must wear protective glasses, sparks direction shall not stand. The replacement material to be confirmed by the material, and a certificate of approval, can use in case of wrong with material. In soda powder, wind pipe repair the old pipe cutting, a new pipeline, expansion joints, and elbow when installing lifting, counterpart, when welding the lower part of it is strictly prohibited standing and traffic, in order to avoid injury, burns, burns. 2, remove the valve electric power supply, pneumatic air source, head and hang them. After loosening bolts disassembly electrical, pneumatic head, using hoist crane, slow and housekeeping put. After removal of valve components shall be in the specified location, laying on the ground rubber pads, beware of equipment and ground damage. Loosen the valve flange screw in tied, staff are not allowed to be on the flange joint surface place to stand, in case of residual soda cuts. Pulverized coal pipe before stop running, pulverized coal in the piping net, should be to prevent the spontaneous combustion of accumulated powder 3, before the assembled valve core, valve seat are subject to inspection qualified rear can assemble, combined with the surface. When assembling, want to clean up the qualified parts, in strict accordance with the process sequence, case packing, wrong. Valve seat, valve core grinding strictly enforce the coarse, fine, fine craft standard, replacing flat grinding sandpaper, all want to grinding tool first put forward, in case of nut and other debris into valve shell. Pipe, valve repair technical measures 1, valve after the on-site inspection, along with the boiler body with hydraulic pressure test. Tooth cushion flat wire should be smooth without mark, crack, etc. , forming filler should be bright and clean, intact. Joint should be 45 & deg; 1200 place, crisscross. Examine the stem and packing box, with bright and clean of sand paper burnish, stuffing box inner surface should be clean, packing should be smooth without scar, the ovality shall & lt; 0. 05 mm faying surface should have no scar, pitting roughness should be 0. More than 8. 2, shell should be intact, in combination with surface should be clean, without grooves and scar, eliminating pitting, pits, silk mark, reaching bright, smooth, roughness reaches 0. 2, the sealing surface without defects. Bearing surface is bright and clean nondestructive, no rust. Steel ball intact, the rotation should be flexible. Seat and copper set of inner surface should be smooth without burr and casing ovality should & lt; 0. 2mm。 Snap ring, gasket ovality should & lt; 0. 1mm。 3, the valve stem and valve core bottom liner clearance to 0. 2 mm, the valve core and valve seat clearance is 0. 3 - 0. 4 mm, the valve core on the valve stem and packing, packing clearance of 0. 15 - 0. 20 mm, the valve cover and valve seat clearance to 0. 2 - 0. 3 mm, washer and the valve cover and valve seat clearance of 1. 0 - 1. 2 mm, gland and seat clearance is 0. 5 - 1. 0 mm。 4, the valve stem in internal rotation valve core should be flexible, loose and 0. 5 mm, the valve core flexible rotation in the seat. Pipe counterpart may not be apparent hi-lo, dig pipeline internal level off, the weld infill. Remove should prevent damage when silk mouth, flexible switch, no leakage in the joint surface, joint has no leakage phenomenon. Even contact zone should be continuous to the width of more than two-thirds, and has a continuous sealing line. Around the snap ring should be put inside groove, the gap between should be uniform. Within the disc in the seat string dynamic gap in 1 - shall be maintained 1. 5㎜。