HDPE steel wire mesh skeleton plastic composite pipe(SRTP Pipe) is a new type of composite wall pipe with integral pipe wall formed by taking high-strength steel wire and polyethylene plastic as raw materials, winding high-strength steel wire as core layer and high-density polyethylene plastic as inner and outer layer. Adding steel wire reinforced mesh to the composite pipe not only greatly improves the pressure resistance of the pipe compared with HDPE solid wall pipe, but also retains the excellent corrosion resistance and scale free characteristics of HDPE solid wall pipe. The reinforcement is coated in continuous thermoplastic to ensure the isolation between the steel wire and the outside world, make the service life of the steel wire longer and ensure the long-term pressure resistance of the pipe. The steel wire mesh winding makes the composite pipe have certain flexibility in the axial direction and strong environmental adaptability while ensuring low linear expansion coefficient. Pipes are widely used in the field of water supply and gas supply. They are new and practical pipes. Today we will introduce its stacking and welding.
How to avoid flattening when stacking HDPE SRTP pipes?
Steel wire mesh skeleton pipe has advanced production technology and material, but to a certain extent, it is also a plastic pipe. There is steel wire skeleton support in the middle, which has good pressure resistance and is widely used. However, if we don't pay attention to handling, loading, unloading and stacking, it may be flattened. How should we deal with this situation?
First, find out the specific reasons. Generally, the steel mesh skeleton pipe is very regular after production. Many times, in order to save space, we will place the pipes with large aperture on the bottom layer and stack them layer by layer. At this time, if the height does not exceed 2.5m, the pipes will not be damaged and flattened. However, if a small-diameter pipe is sleeved inside the large-diameter pipe and sleeved layer by layer, the bottom pipe will be greatly compressed, resulting in the deformation and flattening of the pipe. This is not the quality problem of the pipeline, but the wrong storage and transportation method is used. Therefore, the flattening of the pipeline is mostly in the process of storage and transportation.
Usually, after the pipe is flattened, we should evaluate and test it to see whether the deformation is serious and whether it affects the use. If there is no problem with the tube and it can be used, we can use circular orthotics for treatment. This method is more convenient and accurate. When there is no orthotic device, the pipe can only be knocked to restore it to its original state. I would like to remind you that this method is not desirable and can be used in an emergency. If you want to completely solve the problem of flattening of steel wire mesh polyethylene composite pipes, you should solve it from the source, that is, do not stack too high or too much in the process of storage and transportation, otherwise serious pressure will be generated on the pipes at the bottom, resulting in flattening and out of round pipes. Therefore, in order to ensure the quality and safety of the pipeline, it is necessary to store and transport reasonably and scientifically.
Precautions for welding of electrofusion accessories of SRTP Pipe
In recent years, HDPE steel wire mesh skeleton pipe has been widely used. This new type of improved steel skeleton composite pipe is electrofusion welding, which is the welding method with the least influence by the external environment. When welding, the electrofusion fittings shall be sleeved on the pipe first according to the specified parameters (time) Voltage) energize the electrofusion fitting to melt and weld the inner surface of the electrofusion fitting embedded with electric heating wire and the outer surface of the pipe insertion end; After cooling, the pipes and fittings can be fused together.
Here we share with you some points for attention in the practical application of electrofusion accessories:
The connecting end of the pipe shall be cut vertically to ensure sufficient welding area. Common cutting tools include rotary cutting machine, saw bow, plastic pipe scissors, etc. High temperature cutting shall be avoided to avoid deformation of pipes in case of high temperature. Measure and mark the depth of the fitting or welding area on the pipe with a marker. Notice that the end face of the pipe is cut perpendicular to the axis. After the pipe welding area is cleaned, the depth of pipe fittings shall be re marked. If the end face of the pipe is not cut perpendicular to the axis, some welding areas may be exposed, which will lead to welding accidents, and molten materials flow into the pipe, resulting in hidden dangers in pipe quality.
2.Clean the connector
HDPE steel wire mesh skeleton pipe will form an oxide layer on the surface after being stored for a period of time. Before welding, the oxide layer in the welding area must be completely removed, otherwise the welding quality will be affected and potential safety hazards will be caused. The welding surface of pipes and fittings must be absolutely clean, dry and free of grease. After scraping off the oxide layer, it can be cleaned with polyethylene special cleaner or more than 96% alcohol and debris free colorless paper before installation, and the insertion depth line can be marked.
3.Power on welding
The time and voltage of electric heating shall comply with the regulations of the manufacturer of electric fusion welding machine and electric fusion pipe fittings to ensure the best welded joint at the best voltage and heating time.
Before power on, pay attention to the voltage used and the cross-sectional area of the input cable, insert the welder into the socket of the pipe fitting, and accurately input the welding time (fus10n) and cooling time (cool) calibrated on the pipe fitting. Press the confirm button (ascertain), and the welding machine will display the welding parameters again. After confirmation, press the start-up button again to start welding. After the welding process, the welder will alarm automatically. Please record the welding parameters, operation time and operators on the pipe. Welding temperature of electrofusion fittings: 190 ° C + / - 10 ° C. General principle of HDPE steel wire mesh skeleton pipe welding: PE material can be melted in the range of 190-240 (the melting temperature of raw materials of different brands is generally different). At this time, the pipe and the two melting parts of the pipe are in full contact and maintain appropriate pressure (the pressure of electrofusion welding comes from the thermal expansion of polyethylene itself during welding). The pipe and the pipe can reach their maximum compressive strength only after they are cooled to room temperature.