Installation instructions for hydraulic piping
Hydraulic pipeline installation is a major project of hydraulic equipment installation. The quality of pipeline installation is one of the keys to the normal performance of hydraulic system.
1. When designing and piping, we should first consider the components, hydraulic components, pipe fittings and flanges needed to be connected according to the hydraulic schematic diagram.
2. pipe laying arrangement and direction should be neat and consistent, clear hierarchy. Horizontal or vertical pipe should be used as far as possible, and the non-parallelism of horizontal pipe should be less than or equal to 2/1000; The non-perpendicularity of the vertical pipe should be less than or equal to 2/400. Check with a level.
3. There should be a gap of more than 10mm between parallel or cross pipe systems.
4. The configuration of the pipeline must make the pipeline, hydraulic valve and other components easy to load and unload, maintenance. Any pipe or component in the system should be free to disassemble and assemble as far as possible without affecting other components.
5. Piping must make the pipeline has a certain rigidity and vibration resistance. Pipe supports and clamps should be provided appropriately. The bending pipe shall be provided with a bracket or pipe clamp near the bending point. Pipes shall not be welded directly to supports or pipe clamps.
6. The weight of the pipeline should not be borne by valves, pumps and other hydraulic components and auxiliary; Heavy component weights should also not be supported by piping.
7. For longer pipes, effective measures must be taken to prevent stress caused by temperature changes in pipe expansion.
8. The pipe material used must have clear original basis material, for unknown pipe material is not allowed to use.
9. Pipe diameter of hydraulic system below 50mm can be cut by grinding wheel cutting machine. Pipes with diameters above 50mm should generally be cut by machining method. If gas cutting is used, it is necessary to remove the change in structure caused by gas cutting by mechanical processing, and the welding groove can be pulled out at the same time. Pressure oil lines are not allowed to be cut with a roller type squeeze cutter except for return tubing. Pipe cutting surface must be smooth, remove burr, oxide scale, slag, etc. The incision surface should be perpendicular to the tube axis.
10. When a pipe route is composed of multiple pipe sections and accessories, it should be taken over one section at a time to complete one section. After assembly, the next section should be configured to avoid cumulative error after one welding.
11. In order to reduce local pressure loss, each section of the pipeline should avoid local sharp expansion and reduction of section and sharp bending.
12. The pipe connected with the pipe fittings or flange must be a straight pipe, that is, the axis line of this pipe should be parallel to the pipe fittings, and the axis of the flange is parallel and overlapping. The length of this straight line segment shall be greater than or equal to 2 pipe diameters.
13. Pipe with an outer diameter less than 30mm can be cold-bent. Cold bending or hot bending can be used when the outer diameter of the pipe is 30~50mm. When the outer diameter of the pipe is greater than 50mm, the hot bending method is generally adopted.
14. Welders who weld hydraulic pipelines shall have valid welding certificates for high pressure pipelines.
15. The choice of welding process: acetylene gas welding is mainly used in general carbon steel pipe wall thickness is less than or equal to 2mm pipe. Arc welding is mainly used for carbon steel pipe with wall thickness greater than 2mm. It is better to weld pipes with argon arc welding. If necessary, welding should be done by filling the pipe hole with protective gas.
16. Electrode, flux should be matched with the welded pipe, the brand must have a clear basis information, there is a product certificate, and in the effective use period. The electrode and flux should be dried according to the specifications of the product before use, and kept dry during use, and used on the same day. Electrode coating should be free of peeling and significant cracks.
17. Butt welding should be used for hydraulic pipe welding. Before welding, dirt, oil stains, moisture and rust spots on the surface of the groove and its vicinity 10~20mm wide should be cleaned.
18. Butt welding flanges shall be used for welding pipes and flanges, instead of plug-in flanges.
19. Pipe and pipe fittings welding should be butt welding, not plug-in form.
20. Butt welding shall be used for pipe to pipe welding, and plug-in welding is not allowed.
21. Hydraulic pipe butt welding, weld wall must be 0.3-0.5mm higher than the pipe. It is not allowed to concave into the inner wall. After welding, use file or portable grinding wheel to repair the welding seam which is higher in the inner wall. Remove welding slag and burr to achieve smooth degree.
22. The cross section of butt weld shall be perpendicular to the center line of the pipe.
23. Weld section is not allowed at the corner and should also be avoided between the two bends of the pipeline.
24. When welding pipes, spot welding must be performed according to the installation position, and then disassembled for welding. After welding, plastic assembly must be performed.
25. During the whole welding process, the invasion of wind, rain and snow should be prevented. After welding, welds with wall thickness less than or equal to 5mm shall be cooled naturally at room temperature. Cooling must not be forced by strong winds or drenching.
26. The weld shall be thoroughly welded and the appearance shall be uniform and smooth. Weld seams of pressure pipes shall be sampled for flaw detection inspection.
27. After pipeline piping welding, all pipelines should be pre-installed once according to their positions. Connect the hydraulic components, valve blocks, valve frames and pump stations. Each interface should naturally fit and center, not twist connection. When loosening pipe fittings or flange screws, there shall be no large misalignment, off-seam or off-angle of the center line relative to the fittings surface. If produce this kind of circumstance can use fire to bake plastic eliminate.
28. The pipe clamp and the frame can be welded firmly after all the piping is completed. It can also be interleaved as needed.
29. After piping, welding and pre-installation, the pipe is disassembled again for pickling phosphating. After pickling phosphating the pipeline, hot air into the pipeline for rapid drying. After drying, such as in a few days to install the system, pipe through the hydraulic oil, generally can not be rust treatment, but should be properly kept. If you need to use for a long time, you need to paint antirust coating, it must be in 48 hours after phosphating to paint. It should be noted that the antirust coating must be compatible with the cleaning fluid or hydraulic oil used in future pipeline cleaning.
30. Before the pipes are installed again after pickling, phosphating and drying, the inner wall of each pipe shall be pre-cleaned. After pre-cleaning, the system should be re-installed as soon as possible, and the whole system should be recycled until the cleanliness level of the system design requirements is reached.
31. Hose application is limited to the following occasions: equipment between moving elements; Easy to replace parts replacement place; Suppress transmission of mechanical vibration or noise.
32. The installation of the hose must pay attention not to make the hose and fittings cause additional stress, distortion, sharp bending, friction and other bad working conditions.
33. Before loading the hose into the system, the inner wall and the fittings should also be cleaned.