At present, there are two different products in the market, one is steel skeleton plastic composite pipe, that is, steel skeleton polyethylene plastic composite pipe (manufactured according to CJ/t123 - 2004 standard), and the other is referred to as steel skeleton PE pipe, whose full name is steel skeleton plastic (polyethylene) composite pipe (manufactured according to CJ/t189 - 2007 standard). Although these two kinds of pipes are steel plastic composite pipes, in fact, they are very different from each other in terms of molding methods and product characteristics. The specific comparison is as follows:
1、 Forming method and pipe characteristics
1. Steel skeleton plastic composite pipe: steel mesh welding and plastic extrusion are carried out together; The inner and outer plastic layers of the pipe wall are connected into a whole through the metal mesh in the middle of the pipe wall; Steel wire and plastic interface; The overall structure is similar to reinforced concrete; The two kinds of data are combined into one, and the quality of each part of the pipeline is uniform and stable; There is no danger of layering.
2. Steel mesh skeleton plastic (polyethylene) composite pipe: extrude the inner plastic, apply a layer of hot melt adhesive on the outer wall of the molded inner plastic pipe, surround the steel wire, and then apply a layer of hot melt adhesive. Extrude the outer plastic repeatedly. There are interfaces between pipes and layers, which are easy to delaminate. The steel wire surrounding layer in the pipe is partially separated from the plastic layer. When transporting corrosive media, the steel wire layer will form severe corrosion, which will damage the main body of the pipeline pressure. Because the bearing capacity of the remaining plastic part after the steel wire layer is corroded is very low, pipe explosion may also occur under low pressure. Even if there is no corrosion problem, because the steel wire is not fixed at the end of the pipe (poor bonding), the steel wire will slide between the plastic layers under the effect of pressure, forming a pure plastic pipe with very thin wall thickness, where the steel wire will no longer be reinforced.
II. pipeline structure
1. Steel skeleton plastic composite pipe: the plastic layers inside and outside the pipe wall are connected by the metal mesh in the middle of the pipe wall as a whole (such as reinforced concrete structure), and the two materials are combined as a whole; Because the steel wire surface is lubricated and free of edges and corners, the plastic flow resistance is small during the forming process, the extrusion is even, and the quality of all parts of the pipe is even and stable. Because of the welded mesh, the skeleton mesh distance is consistent, the structure is stable, and the support effect on the plastic is strong.
2. Steel wire mesh skeleton plastic (polyethylene) composite pipe: the surrounding formed steel wire mesh is bonded with the internal and external plastics under the effect of hot melt adhesive. Because the characteristics of polyethylene material itself are difficult to bond, the bonding is general, because it is formed repeatedly, the quality uniformity of the pipe is poor. The steel wires are only wrapped together without welding. The mesh distance of the steel wire mesh is uneven, and the structure is unstable. Where the steel wire distance is large, the strength of the pipeline is very low. The steel mesh has poor support for plastic, and the pipe end shrinks severely.
3、 Pipe fittings
1. Steel skeleton plastic composite pipe: all pipe fittings include electric melting sleeve, elbow, tee, etc. The internal reinforcement skeleton is the reinforcement part, which is matched with the pipeline. The pressure and temperature resistance of the pipeline system are consistent with the dimensions of the pipeline and pipe fittings.
2. Steel mesh skeleton PE pipe: frameless pure plastic pipe fittings are generally used together with pipe fittings. The pressure rating of the pipe fittings is lower than the pressure rating of the pipe body, or the wall thickness of the pipe fittings is large, resulting in a reduction in the size of the pipe fittings.
