3.2 pipeline installation is generally carried out in the following order: 1) underground pipe first and then aboveground pipe; 2) large tube first and then small tube; 3) stainless steel, alloy steel pipe and then carbon steel pipe; 4) clamp the casing first and then the single pipe.
When it is unqualified, the spot check shall be doubled.
3.5 installation of cast iron pipes 3.5.1 asbestos cement shall be filled from bottom to top and filled and beaten in layers, and each layer shall be filled and beaten at least twice.
2.1.9 for stainless steel pipes and fittings requiring intergranular corrosion test in the design documents, the supplier shall provide documents of intergranular corrosion test results, and its indexes shall not be lower than those specified in the design documents.
Those unqualified shall not be used.
General construction process for medium and low pressure industrial pipeline installation 1.
3.5.9 the rubber ring used for pipe interface shall be free from defects such as pores, cracks, sagging or aging.
After straightening, the pipe shall be cleaned.
3.5.6 the hemp used for filling shall have toughness, long fiber and no hemp skin, and shall be soaked in petroleum asphalt and dried in the air.
Anti freezing measures shall be taken in cold seasons.
The braid filling depth after tightening shall be 1 / 3 of the socket depth and shall not exceed the inner edge of the triangular groove of the socket.
Operation conditions 2.2.1.
3.5.4 the circumferential clearance of cast iron pipes and socket joints laid along the straight line shall be uniform.
Operation process 3.1 ― when making pipes at the operation site, it shall be carried out in accordance with the relevant provisions of the process standard for prefabrication of medium and low pressure pipelines.
The unqualified ones shall not be used.
If it is still unqualified, this batch of valves shall not be used.
2.2.
2.1 construction preparation 2.1 material requirements 2.1.1 pipeline components and pipeline supports must have the manufacturer’s quality certificate, and their quality shall not be lower than the provisions of the current national standards.
3.7 installation of anti-corrosion lined pipe 3.7.1 before the installation of lined pipe, check the integrity of lining layer and keep the pipe clean..
3.6 installation of non-ferrous metal pipes 3.6.1 straightening of copper, lead and titanium pipes should be filled with sand and adjusted with straightener instead of hammering.
3.5.8 when asbestos pool and expansive cement are used as interface materials, the filling depth shall be 1 / 2-1 / 3 of the interface depth.
2.1.5 the valves of the following pipelines shall be subject to shell pressure test and sealing test one by one.
2.1.7 the safety valve shall be tested and adjusted according to the opening pressure in the design document.
The quality of pipes with special requirements in the pipe has met the provisions of design documents.
2.1.6 for the valves conveying the non combustible fluid and non-toxic fluid pipeline with the design pressure less than or equal to 1MPa and the design temperature of – 29 ℃ ~ 186 ℃, 10% and no less than one valve shall be randomly selected from each batch, and the shell pressure test and sealing test shall be carried out.
3.5.7 the thickness of oil braid shall be 1.5 times of the interface gap.
The fixed welded junction of the pipeline connecting the machine shall be far away from the machine.
The civil works related to the pipeline have passed the inspection and meet the installation requirements, and the handover procedures have been handled.
3.5.5 during construction under large temperature difference between day and night or negative temperature, both sides of the middle of the pipe shall be filled and compacted, and the top shall be filled and covered.
2.2.4 the interior of pipes, pipe fittings, valves, etc.
2.2.2 the equipment connected with the pipeline has been aligned and qualified, and the foundation grouting has met the strength requirements.
Scope of application this process is applicable to industrial metal pipeline installation works with design pressure not greater than 10MPa and design temperature not exceeding the allowable service temperature of materials.
During filling, the rubber ring shall be flat and compacted without looseness, distortion, fracture, etc.
2.3.5 relevant processes such as degreasing, internal anti-corrosion and lining that must be completed before pipeline installation have been completed.
3.
Trapezoid Rubber Magnetic Chamfer
2.1.4 the lining quality of anti-corrosion lined pipeline shall comply with the provisions of the current national standard code for anti corrosion engineering and acceptance of industrial equipment and pipeline.
3.6.5 when installing the copper corrugated expansion joint, the straight pipe length shall not be less than 100mm.
After the filling is compacted, the surface shall be flat and tight, and shall be wet cured for 1-2 days and nights.
has been cleaned without sundries.
3.5.2 the expansion cement shall be properly proportioned, used in time, tamped in layers, flattened, the surface concave into the socket edge shall not be more than 2mm, and wet curing shall be carried out in time.
3.3 construction procedure: 3.4.
2.1.5.1 valves for pipelines conveying highly toxic fluid, toxic fluid and combustible fluid; 2.1.5.2 ― valves for conveying non combustible and non-toxic fluid pipelines with design pressure greater than 1MPa or design pressure less than or equal to 1MPa and design temperature less than – 29 ℃ or greater than 186 ℃.
This process is not applicable to special pipelines for nuclear power plants, special pipelines for mines and long-distance transmission pipelines.
2.
3.6.2 when copper pipe is threaded, the threaded part shall be coated with graphite glycerin.
3.6.4 the lead and aluminum pipes shall be protected with steel pipes, which shall pass the pressure test before being installed into the steel pipes.
2.2.3 pipeline components and pipeline supports have passed the inspection.
Cement mortar shall be directly plastered on the outside of the rubber ring, and its height shall be flush with the socket.
3.6.3 when installing bolts of lead flanges, steel washers shall be added between nuts and flanges.
2.1.8 for materials requiring low-temperature impact toughness test in the design document, the supplier shall provide the document of low-temperature impact toughness test results, and its index shall not be lower than that specified in the design document.
Each circle of braids shall be overlapped with each other by 100-150mm and compacted and tightened.
2.1.3 the material of alloy steel pipeline components shall be rechecked by spectral analysis or other methods, and shall be marked.
3.5.3 when installing flanged cast iron pipes, pipes of different lengths shall be used for adjustment, and forced connection is not allowed.
2.1.2 the material, specification, model and quality of pipeline components and pipeline supports shall comply with the provisions of the design documents, and the appearance inspection shall be carried out according to the current national standards.
