(1) Galvanized steel pipe screw connection
1) Fire protection system pipes less than DN100 use galvanized steel pipes and screw connections. When the pipeline is installed, the thread should be smooth, complete and free of segments. The filler of the thread mouth should be made of tetrafluoroethylene raw material tape or white lacquered hemp silk. The pipe should be installed tightly at one time. Do not enter pipes.
2) The threaded connection of the pipeline is processed by an electric threading machine. The processing of the thread should be correct, clear, complete and smooth, without burrs or broken wires, and the total length of missing wires should not exceed 10% of the thread length.
3) When threaded connection, the filler is made of white thick lacquered hemp silk or raw material tape, tightened once, and shall not be screwed back, leaving 2~3 turns of thread after tightening.
4) After the pipes are connected, clean up the stuffing squeezed out of the thread, and the stuffing should not squeeze into the lumen, so as not to block the pipeline, and at the same time, carry out anti-corrosion treatment on the exposed threads.
(2) Mechanical grooved rigid interface pipe installation:
1) Preparation before installation
①Before construction, you should be familiar with the construction period drawings, relevant technical requirements and acceptance standards, construction methods and technical essentials for various pipeline installations, prepare detailed construction plans, and guide construction; establish a construction quality assurance system to control the quality of each process during the construction process , so as to ensure that the pipeline engineering construction meets the requirements of design and acceptance specifications;
②Pipeline cutting: Grinding wheel cutting machine should be used for cutting galvanized steel pipes. The fracture of the pipes should be flat and free of defects such as burrs, and the foundation should be polished with angular sand to remove oxides.
③Before the pipeline is prefabricated, the flatness of the nozzle needs to be checked, and the flatness must meet the requirements of the specification.
④ Casings should be added when pipes pass through walls or floors, and the gap between pipes and casings should be filled with flexible non-combustible materials.
2) Installation process
①Construction sequence: After the pipes pass the inspection, first do the pipe galvanizing inspection, and then carry out the pipe blanking and groove prefabrication according to the pipe prefabrication processing single-line diagram; The support (hanger) frame is prefabricated, processed and installed; after the prefabricated pipeline has passed the inspection, it can be put into pipeline installation.
②Pipeline groove processing: use electromechanical grooving machine for processing. When prefabricating pipeline grooving, the corresponding grooving mold should be configured (adjusted) according to the size of the pipe diameter, and the height of the rolling bracket of the pipe should be adjusted at the same time to keep the processed The level of the pipe is aligned with the center of the electromechanical grooving machine to ensure smooth rotation during pipe processing and ensure the quality of groove processing;
③Pipe end inspection: After the groove of the pipe is pressed, the depth and width of the groove should be strictly inspected to meet the requirements. The sealing performance; at the same time, the groove extrusion processing part of the inner wall of the pipeline should be protected by painting with anti-rust paint;
④ Check and lubricate the liner of the pipe pair and clamp: before the pipe is assembled and installed, the type and specification of the clamp liner used should be checked to meet the design and product requirements; when the liner of the clamp is installed, it should be Apply a thin layer of lubricant to the flange and the outside of the liner, and then put the liner on one side of the pipe to ensure that the liner does not protrude from the pipe end. After the other side of the pipe is in place, install the liner in place. Should not extend into either slot.
⑤Installation of the clamp shell of the pipeline: before the assembly and installation of the pipeline and pipe fittings, the type and specification of the clamp shell used must also be checked to meet the design and product requirements; when installing the clamp shell, the clamp shell should be removed first. A bolt at one end is put on the outside of the liner on the pipe, and the clamp shell is moved so that the two ribs of the clamp shell match the groove, and then the bolt is inserted for positioning. The concentricity of the pipeline installation or the three When the installation and opening direction of the pipe, elbow, and valves meet the requirements of the design and construction drawings, the bolts on both sides can be tightened evenly in turn to ensure that the two ribs of the clamp shell of the pipe are in even and close contact with the pipe groove, so as to ensure The tightness, rigidity and strength of the pipe clamp interface meet the design and product technical requirements;
⑥Installation of pipe clamp type "mechanical tee": After the pipe is installed in place, locate it on site according to the coordinate position set in the construction drawing, and use a special matching electric mechanical drilling machine to drill holes (select a special matching drill bit), and the hole diameter should be It is slightly larger than the "director" installation ring of the "mechanical tee": when installing the "mechanical tee", check whether its product specifications and dimensions meet the product design requirements. When installing the "orienter" and the installation ring, make sure that Align with the opening. After installation and positioning, the bolts on both sides should be tightened evenly, so that the "mechanical tee" can be tightly and evenly combined with the pipe, and the tightness, rigidity and strength of the interface of the "mechanical tee" can be guaranteed.
⑦Pipeline processing and prefabrication: The processing and prefabrication of pipelines should be concentrated in the processing shed (platform), and prefabrication should be carried out according to the construction materials and the one-line diagram drawn after on-site surveying and mapping; the quality of processing and prefabrication should be strictly controlled, and the processed Sampling inspection and pressure test inspection are carried out for the pipelines, and timely rectification and adjustment are found to ensure that the quality of pipeline prefabrication, processing and installation is under control;
⑧Flange connection between pipes, valves and equipment: When connecting pipes and equipment, it is advisable to use short pipes for flange connection first, after positioning welding and forming, galvanized and then installed in place, and then connected to the system pipes.
Read more : Features of galvanized steel pipe