Executive standard: industrial metal pipeline engineering construction and acceptance specification GB50235-97
1 construction program
1.1 large diameter pipe and special material pipeline, priority should be given to install. Construction should be according to the ground after the first underground, first director branch, after the first large tubular, was finally installed transmission equipment piping principle.
Support and hanger 1.2 piping shall be prefabricated in advance, support and hanger installation should be installed with pipes.
1.3 pipe installation, the valve installation position, should make the temporary pipe section, in order to avoid the pressure test, purge by repeated disassembly damage. Regulating valve installed in the pipeline pressure test, purge after a complete.
1.4 pipe hole by mechanical method as far as possible, the instrument should be used joint hole drilling machine.
1.5 steam pipe should be installed in the process pipeline construction.
1.6 pressure test should be in the pipeline weld inspection, acid washing purification treatment after passing the.
1.7 the lubrication pump and seal oil lines should be in the oil system before commissioning the construction.
1.8 pipeline construction procedure:
Piping material inspection, pipe supports and hangers prefabricated, pipeline installation, pipeline inspection and test pressure of pipeline purging and constituent elements of pipeline and support reduction.
2 construction methods
2.1: carbon steel pipe groove machining should adopt mechanical method or oxy acetylene flame chamfering, small diameter pipes should be used with mechanical chamfering; air plasma cutting processing groove stainless steel pipe. Use oxygen acetylene flame, must remove the surface oxide layer.
2.2 pipeline and equipment connected (especially the large unit transmission equipment, installation of pipelines and equipment center) center should be free counterparts, no method to use strong pull, push, strong twist to compensate the installation error and high precision machinery, pipeline connected, from inside to outside (near the end of equipment) preparation, to avoid welding near the equipment, resulting in welding deformation and impact equipment alignment accuracy.
Tighten the bolt 2.3 and high speed precision machinery connected, force wrench to force uniform.
2.4 and the pump connecting pipe, at the last turn on the front, should use the blind plugging pipe, to prevent debris into the equipment.
2.5 before welding groove and the range of 50mm on both sides of rust, oil should be clean. Stainless steel welding, on both sides of the weld shall be within the range of 50mm coated with special protective cream, to prevent the welding slag splashing and damage the surface of the pipe, welding shall be cleaned spatter and protective cream.
2.6 according to requirements for weld inspection, after passing the inspection reports. Unqualified weld repair, strict control of the same weld repair of not more than two times.
Pressure test of 2.7 pipes, should press pressure test system diagram system passes the pressure test, should be promptly after discharge and sweep clean.
Sweeping shall be purging system diagram system was blowing 2.8 pipeline. Blow the instrument hole plate, a regulating valve element properly isolated or removed, replaced with temporary short, after blowing eligibility to reset.
2.9 co-ordinate arrangements for the welding operation plan, follow the first high-rise low layer, the first principle of indoor outdoor, minimize the winter welding surface.
2.10 each weld shall make smooth reading, to ensure the welding interlayer temperature.
2.11 below 0 ℃ when welding, welding in the range of 100mm was heated to 50 ℃, then start welding.
2.12 welding should take shelter from the wind, rain, snow effect, relative humidity of not more than 90%. When necessary, erection of a shed, to avoid a direct impact.
