FRP pipe installation principles
The pipeline installation sequence is based on the partition area and system, first the large diameter and then the small diameter, the lower layer first and then the upper layer. In order to reduce the impact of welding stress on the installation accuracy of the machine, the gap between indoor and outdoor pipelines should be left outdoors.
I. Pipeline installation requirements
1. Before installation of the pipeline, the contents of the pipeline installation, such as equipment nozzles, embedded parts, reserved holes, and steel structures, should be reviewed.
2. The slope of the pipeline should be adjusted according to the requirements of the drawing. The adjustment method can use the support to achieve the slope requirements. The weld seam should be set at a place that is convenient for maintenance and observation.
3. The pipelines connected to the transmission equipment should be cleaned internally before installation, and the welding fixed nozzles should generally be kept away from the equipment to avoid the impact of welding stress on the installation accuracy of the transmission equipment.
4. Before the pipeline is connected to the machine, it should be prevented from being strong. Check the parallelism and coaxiality of the flange in a free state.
5. The safety valve should be installed vertically. When it is put into trial operation, it should be adjusted in time. The final adjustment of the safety valve is performed on the system, and the opening and returning pressure should conform to the design document.
6. Before installing the valve, check its model according to the design document, and determine its installation direction according to the flow direction of the medium. When the valve and the pipeline are connected by flange or thread, the valve should be installed in the closed state; if it is installed by welding, the valve must not be closed.
7. Temporary replacement of instrument components: All instrument components are replaced with temporary components when they are installed. After the pressure test, flushing, and purging work is completed, they are officially installed before feeding.
Installation of FRP pipes and composite pipes
① Before construction, the FRP pipe should be inspected for appearance and dimensions, and inspected and accepted according to the factory certificate.
② The pipeline installation drawing is the basis of the pipeline installation project, the laying of FRP / PVC pipe (including connection form, coordinates, elevation, slope, slope direction, etc.) support, the connection of FRP / PVC pipe with equipment, pipeline accessories, and installation of pipeline accessories The position, support, etc. shall all conform to the design drawings, and any changes must be resolved through consultation with the design unit.
③ For pipe installation, install pipe accessories from one end of the pipe to the other end according to the pipe section divided by the pipe installation drawing, and then set up a bracket or support (if necessary, temporary support is required during the installation process). When the pipeline is being hoisted, protective measures must be taken on the outer wall surface to prevent direct contact with the steel wire rope to avoid local stress.
④ The connection point of FRP pipe is only allowed in the straight pipe part. The distance between the butt-welded connection point and the edge of the pipe support should be greater than the outer diameter of the pipe and not less than 100mm; the distance between the socket connection and the edge of the pipe support should be greater than 150mm.
⑤ The connection structure of the pipeline includes socket connection, flange connection (weld ring looper flange connection and composite flat welding flange connection) and butt welding connection. This project will determine the installation method according to the specific requirements of the design file.
⑥ The installation workers engaged in welding must have a welder qualification certificate, be familiar with the adhesive properties of FRP / PVC pipes and their installation methods, and have a skilled PVC welding operation ability.
在 Before the socket is connected, the dirt on the inner wall of the PVC pipe should be removed first, and then the socket plug should be inserted into the socket. The socket must not have defects such as skew and cracks. After reaching the socket depth, PVC welding can be performed.
⑧ The socket part should be reinforced with FRP. A layer of R glue is evenly applied to the reinforced part. The coating thickness is uniform and must not be leaked or flowed. Then cover with a layer of glass cloth, apply unsaturated resin, and cover glass cloth. Repeat until Up to the required thickness.
⑨ When the socket is not installed properly and needs to be repaired, the socket plug and socket must be remade, and the used socket socket must not be used.
时 When the flange is connected to the pipe, both the inner and outer sides must be welded to the pipe. The inclination of the flange surface and the pipe axis should be less than or equal to 1/100 of the outer diameter of the pipe. The flange connection should be strictly centered, the maximum allowable deviation in the axial direction is not greater than 2mm, and the skew cannot be eliminated by the method of strong bolts. Tighten the bolts in two steps, first evenly and symmetrically, and then tighten the bolts.
Production and installation of pipe supports and hangers
① The pipe racks produced on site shall be strictly in accordance with the specifications and drawings, and shall be painted and protected. The hanger ear supports of the rod hangers and spring hangers shall be welded in accordance with the steel structure manufacturing standards and subjected to 100% penetration or magnetic particle inspection.
② The positions of all pipe racks shall be indicated in the one-line diagram.
③ When the pipeline is installed, the bracket should be fixed and adjusted in time. The location of the bracket should be accurate, the installation should be flat and firm, and the contact with the pipe should be close.
④ The fixing bracket should be installed according to the requirements of the design document, and it should be fixed before the compensator is pre-stretched.
⑤ The sliding surface of the guide bracket or sliding bracket should be clean and flat, and there should be no skew or jamming. The installation position should be offset from the center of the support surface in the opposite direction. The offset should be 1/2 of the displacement value or meet the design document requirements. The thermal insulation layer must not hinder its displacement.
⑥ When using temporary support for pipeline installation, it must not conflict with the position of the official support and be clearly marked. After the pipeline installation is completed, it should be removed.
⑦ FRP / PVC pipes and pipe racks (including supports) must not be directly bonded or welded. FRP / PVC pipe fixing pipe rack pipe fittings (pipe clamps, pipe brackets or pipe clamps) and the outer wall of the pipe should be cushioned with a thickness of not less than 3mm rubber blocks or other soft pads.
后 After the installation of the pipeline is completed, the form and position of the bracket should be checked one by one according to the design document.