1 and Type A pipes are HDPE hollow wall wound pipes with flat ends; B-type pipe is a socket winding pipe, and the mouth end is a socket.
2. There is no electric fuse at the end of type A tube, and there is an electric fuse at the end of type B tube.
3. The A-shaped tube is flat inside and outside, with a structural wall in the middle, which represents a hollow winding tube; Generally speaking, double-walled corrugated pipe and carat pipe are both B-type pipes. However, the steel-plastic composite steel strip pipe is not counted because it is described in GB/T 19472.
4. The B-type pipe is made of high density polyethylene (HDPE) with German equipment and technology, which is wound and molded in hot melt state, cooled by natural wind and demoulded in cold state, and conforms to the national standard GB/T 19472.2-2004. The A-type pipe adopts domestic equipment and technology, takes high-density polyethylene as raw material, is wound and formed in hot melt state, and is water-cooled, which conforms to the national standard GB/T 19472.2-2004. In this process, the square tube is extruded, cooled by water, shaped, wound into a circular tube and cooled by water.
Compared with the two, the advantages of B-ultrasound tube:
A) Hot-melt winding, in which the inner and outer walls of the structural wall are wound synchronously, and the pipe is uniform as a whole without weld.
B) Air cooling is adopted, so that the heat stored in the tube during molding is completely dissipated, internal stress will not be formed, and delamination and cracking will not occur.
C) Cold demoulding, that is, when the pipe is cooled to normal temperature, the pipe will be demoulded by shrinking the mold, and the pipe will not be deformed. In contrast, hollow tubes exist.
Defects are:
A) There are obvious welds, which are long and difficult to control.
B) The water cools quickly, resulting in uneven heat dissipation and stress on the structural wall. Poor control often leads to spring-like cracking.
C) The smooth outer wall can not effectively restrain the longitudinal displacement caused by thermal expansion and contraction of PE material, which often causes stress concentration at both ends of the pipeline, damages the joint or the connection between the pipeline and the inspection well, and causes water leakage.
5. The inertia distance of B-type pipe (HDPE wrapped with B-type pipe) can be adjusted continuously, and the maximum value can reach 19.8, so the pipe ring stiffness is high, and pipes with DN above DN 1500 can still produce pipes with DN above 16KN/m2. However, the wall height of A-type pipe (HDPE hollow wall winding pipe) is limited, and the adjustable moment of inertia can only reach 5. The ring stiffness of the produced pipe is basically 8KN/㎡, and when the pipe is greater than DN 1000, its ring stiffness is SN4(≥4KN/㎡).
6.B-tube (HDPE wound B-tube) requires extremely high performance of raw materials in production, so except for 2% color masterbatch, all others are made of HDPE, so the price is relatively low. However, the A-type pipe (HDPE hollow wall winding pipe) has more consumables per ring stiffness, so the cost is higher. However, due to the low investment in production equipment and low threshold, there are many manufacturers. In the disorderly market competition, in order to gain an advantage in cost, a large number of inorganic substances (calcium carbonate) and recycled materials are used, so that the market price difference is very large and ridiculously low.
7. The B-type pipe (HDPE wound B-type pipe) adopts socket-type electrofusion connection (rigid interface), and the interface part adopts socket and electrofusion at the same time.
This use ensures the bearing capacity of the pipe joint and the sealing performance of the joint. B-type pipe (HDPE wound B-type pipe) has a strong ability to withstand unevenness, and the construction methods can be diversified. In the area requiring quick backfilling, B-type pipes (HDPE wound with B-type pipes) can be pre-welded on the ground and then put into the groove. A-type pipe (HDPE hollow wall winding pipe) is connected by (electric) hot melt tape. Due to the deformation of the pipe end, the (electric) hot melt tape cannot be completely stuck on the pipeline, and it must be welded in the groove during construction, which requires a lot of earthwork excavation and the construction speed is slow. The (electric) hot-melt belt has a poor bearing structure, and the pipeline is welded with long seams, which is not suitable for laying in soft soil foundation or uneven settlement area.
8. Compared with B-type pipe (HDPE wound B-type pipe) and A-type pipe (HDPE hollow wall wound pipe), B-type pipe is superior to A-type pipe in technology and B-type pipe is superior to A-type pipe in application. Under the same index, the materials used in the two kinds of pipes are similar, and the normal price should be similar. The performance-price ratio of B-tube is obviously better than that of A-tube.
9.B-type pipe (HDPE wound B-type pipe) is widely used in national and provincial key projects, especially in coastal areas with uneven settlement. However, A-type pipe (HDPE hollow wall wound pipe) is restricted in some key projects and generally not used in coastal areas because of unreasonable technology and structure, insufficient pure materials and low engineering safety.
References:
/news/faq/ 107.html