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Introduction to Hydraulic System Piping

The hydraulic pipeline device is a primary project of hydraulic equipment installation. The quality of the pipeline device is one of the keys to the normal operation function of the hydraulic system.
1. When planning and piping, a comprehensive consideration should be given to the components, hydraulic components, pipe joints, and flanges that need to be connected based on the hydraulic schematic diagram.
2. The laying, arrangement, and direction of pipelines should be neat and common, with clear layers. Try to choose horizontal or straight pipe layout, and the unevenness of horizontal pipes should be ≤ 2/1000; The non straightness of a straight pipeline should be ≤ 2/400. Check with a level gauge.
3. There should be a gap of more than 10mm between parallel or intersecting pipe systems.
4. The equipment of pipelines is necessary to facilitate the loading, unloading, and repair of pipelines, hydraulic valves, and other components. Any section of pipeline or component in the system should be able to be disassembled and assembled freely as much as possible without affecting other components.


5. When piping the hydraulic system, it is necessary to ensure that the pipeline has a certain degree of rigidity and anti oscillation ability. Pipe supports and clamps should be appropriately equipped. Twisted pipes should be equipped with brackets or clamps near the bending point. The pipeline shall not be directly welded to the bracket or pipe clamp.
6. The component of the pipeline should not be accepted by valves, pumps, and other hydraulic components and accessories; Heavy component components should not be supported by pipelines.
7. It is necessary to consider useful methods for longer pipelines to prevent stress caused by temperature changes that cause pipe expansion and contraction.
8. It is necessary to have a clear initial basis for the pipeline raw materials used, and pipes with unknown raw materials are not allowed to be used.
9. Hydraulic system piping with a diameter of less than 50mm can be cut with a grinding wheel. Pipes with a diameter of 50mm or more should usually be cut by mechanical processing. If gas cutting is used, it is necessary to use mechanical processing methods to remove the parts that have changed due to the arrangement of gas cutting, and at the same time, the welding groove can be turned out. Except for the return oil pipe, it is not allowed to use a roller type kneading cutter to cut the pressure on the pipeline. It is necessary to cut the surface of the pipe flat and remove burrs, oxide skin, slag, etc. The cut surface should be straight with the axis of the pipe.
10. When a pipeline is composed of multiple pipe sections and supporting components, it should be received one by one, completed one section, assembled, and then equipped with the next section to prevent accumulated errors after one welding.
11. In order to reduce partial pressure loss, each section of the pipeline should prevent rapid expansion or reduction of the cross-section and sharp twists and turns.
12. The pipe connected to the pipe joint or flange needs to be a straight section, that is, the axis of this section of pipe should be parallel and coincident with the axis of the pipe joint or flange. The length of this straight line segment should be greater than or equal to 2 times the pipe diameter.
13. Cold bending method can be used for pipes with an outer diameter less than 30mm. When the outer diameter of the pipe is between 30-50mm, cold bending or hot bending methods can be used. When the outer diameter of the pipe is greater than 50mm, the hot bending method is usually used.
14. Welders who weld hydraulic pipelines should hold a valid high-pressure pipeline welding qualification certificate.
15. Selection of welding technology: Acetylene gas welding is mainly used for pipes with a wall thickness of usually 2mm or less in carbon steel pipes. Arc welding is mainly used for pipes with carbon steel pipe wall thickness greater than 2mm. It is best to use argon arc welding for the welding of pipes. For pipes with wall thickness greater than 5mm, argon arc welding shall be used for priming and Arc welding shall be used for filling. When necessary, welding should be carried out by filling the pipe hole with maintenance gas.
16. Welding rods and fluxes should be matched with the welded pipe material, and their trademarks must be clearly based on the material, have a product qualification certificate, and be within the useful use period. Welding rods and fluxes should be dried according to the rules of their product manual before use, and they should be kept dry during use and used on the same day. The electrode coating should be free from falling and obvious cracks.
17. Butt welding should be used for hydraulic pipeline welding. Before welding, dirt, oil stains, moisture, and rust spots on the surface of the groove and its adjacent areas with a width of 10-20mm should be removed and cleaned.
18. Butt welding flanges should be used for welding between pipelines and flanges, and piercing flanges should not be used.
19. Butt welding should be used for the welding of pipes and pipe joints, and penetration welding should not be used.
20. Butt welding should be used for welding between pipelines, and penetration welding is not allowed.

Post time: Jun-25-2023