Created on:2021-12-15 14:19

Installation of hydraulic equipment_ Installation requirements of hydraulic pipeline

Installation of hydraulic equipment_ Installation requirements of hydraulic pipeline

(1) During pipe layout design and piping, the components, hydraulic components, pipe joints and flanges to be connected shall be considered comprehensively according to the hydraulic schematic diagram.

(2) The laying arrangement and direction of pipelines shall be neat and consistent, with clear layers. Horizontal or vertical pipe laying shall be adopted as far as possible, and the unevenness of horizontal pipe shall not exceed 2 / 1000; The non perpendicularity of vertical pipes shall not exceed 2 / 400. Check with a level gauge.

(3) There shall be a gap of more than 10mm between parallel or cross piping systems.

(4) The pipeline must be configured to facilitate the loading, unloading and maintenance of pipelines, hydraulic valves and other components. Any section of pipe or element in the system shall be able to be disassembled freely without affecting other elements.

(5) When piping, the pipeline must have certain rigidity and anti vibration ability. Pipe supports and clamps shall be properly equipped. For bent pipes, supports or pipe clamps shall be set near the bending point. Pipes shall not be directly welded to supports or clamps.

(6) The weight of the pipeline shall not be borne by valves, pumps and other hydraulic components and accessories, nor shall the pipeline support the weight of heavier components.

(7) For long pipes, effective measures must be taken to prevent the stress caused by the expansion of the pipe due to temperature change.

(8) The pipe material used must have a clear original material basis, and the pipe with unknown material is not allowed to be used.

(9) The pipes of hydraulic system with a diameter of less than 50mm can be cut by grinding wheel cutting machine, and the pipes with a diameter of more than 50mm shall generally be cut by machining method. If gas cutting is used, the organization change part formed by gas cutting must be machined, and the welding groove can be turned out at the same time. Except for the oil return pipe, the pressure oil pipe is not allowed to be cut with the roller type extrusion cutter. The cutting surface of the pipe must be flat, and the burr, scale, slag, etc. shall be removed. The cut surface shall be perpendicular to the pipe axis.

(10) When a pipe is composed of multiple pipe sections and supporting parts, it shall be connected section by section in turn, one section shall be completed, and the subsequent section shall be configured after assembly, so as to avoid cumulative error after one-time welding.

(11) In order to reduce the local pressure loss, each section of the pipeline shall avoid local sharp expansion or reduction of the section and sharp bending.

(12) The pipe connected with the pipe joint or flange must be a straight pipe, that is, the axis line of this pipe shall be parallel or coincide with the axis of the pipe joint and flange. The length of this straight section shall not be less than twice the pipe diameter.

(13) Cold bending method can be adopted for pipes with outer diameter less than 30mm. When the outer diameter of the pipe is 30-50mm, the cold bending or hot bending method can be used. When the outer diameter of the pipe is greater than 50mm, the hot bending method is generally adopted.

(14) Welders welding hydraulic pipes shall hold valid high-pressure pipe welding certificates.

(15) Selection of welding process: acetylene gas welding is mainly used for pipes with general carbon steel pipe wall thickness no more than 2mm. Arc welding is mainly used for carbon steel pipes with wall thickness greater than 2mm. Argon arc welding is preferred for pipe welding. Pipes with wall thickness greater than 5mm shall be primed by argon arc welding and filled by electric arc welding. If necessary, the method of filling the pipe hole with shielding gas shall be used for welding.

(16) The welding rod and flux shall match the welded pipe materials, and the brand must have clear basis data, product certificate and within the valid service life. Welding rods and fluxes shall be dried according to the product instructions before use, and shall be kept dry during use and used on the same day. The electrode coating shall be free from falling off and obvious cracks.

(17) Butt welding shall be adopted for hydraulic pipeline welding. Before welding, the dirt, oil stains, moisture and rust spots on the surface of the groove and its vicinity with a width of l0-20mm shall be removed.

(18) Butt welding flange shall be used for the welding of pipeline and flange, and plug-in flange shall not be used.

(19) Butt welding shall be adopted for the welding of pipes and pipe joints, and plug-in welding is not allowed.

(20) Butt welding shall be adopted for pipe to pipe welding, and plug-in welding is not allowed.

(21) when the hydraulic pipeline adopts butt welding, the inner wall of the weld must be 0.3-0.5mm higher than the pipeline. Concave into the inner wall is not allowed. After welding, use a file or hand-held grinding wheel to level the weld higher in the inner wall. Remove welding slag and burr to achieve smoothness.

(22) the section of butt weld shall be perpendicular to the center line of the pipe.

(23) the weld section shall not be at the corner, nor between two bends of the pipe.

(24) when welding piping, spot welding and positioning must be carried out according to the installation position, then removed for welding, and then assembled and reshaped after welding.

(25) during the whole welding process, the invasion of wind, rain and snow shall be prevented. After pipe welding, welds with wall thickness less than or equal to 5mm shall be cooled at room temperature, and forced cooling by strong wind or water spraying is not allowed.

(26) the weld shall be fully welded and the surface shall be uniform and flat. The welds of pressure pipes shall be subject to sampling flaw detection.

(27) after the pipe is welded, all pipes shall be pre installed once according to the position. Connect each hydraulic element, valve block, valve frame and pump station. All interfaces shall be naturally pasted and centered, and shall not be connected by strong torsion. When loosening the pipe joint or flange screw, there shall be no large dislocation, seam separation or seesaw angle relative to the center line of the joint surface. If this happens, it can be eliminated by fire shaping.

(28) the pipe clamp can be welded firmly with the frame after all piping is completed, or it can be crossed as required.

(29) after piping, welding and pre installation, the pipeline shall be disassembled again for pickling and phosphating treatment. After pickling and phosphating, the pipeline is quickly dried by hot air. After drying, if the system is reassembled and the hydraulic oil is filled in the pipe within a few days, the antirust treatment may not be done, but it shall be kept properly. If it needs to be used for a long time and antirust coating is required, it must be coated after phosphating treatment for 48h. It should be noted that the antirust coating must be compatible with the cleaning fluid or hydraulic oil used for pipeline cleaning in the future.

(30) before the pipeline is installed again after acid pickling, phosphating and drying, the inner wall of each pipeline shall be pre cleaned first. After pre cleaning, the system shall be reassembled as soon as possible, and the overall circulating purification treatment of the system shall be carried out until the cleanliness level required by the system design is reached.

(31) the application of hose is limited to the following occasions: between movable elements of equipment; Easy to replace parts; Suppress the transmission of mechanical vibration or noise.

(32) when installing the hose, be careful not to cause additional stress, distortion, sharp bending, friction and other adverse conditions to the hose and connector.

(33) before the hose is installed into the system, the inner cavity and joint shall also be cleaned.

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