With the continuous increase of market demand, there are more and more pipeline structures and types using HDPE as the main raw material in the market. Manufacturers have different pipeline interface structures according to their regional geological conditions. Therefore, there are also multiple connections between pipelines. Methods, the main connection methods currently on the market are as follows:
1. Hot-melt connection
(that is, the material of the same material pipe is melted into one body after high temperature)
Hot-melt butt connection: Two pipes are heated by a heating plate, butt-welded as a whole.
Advantages: simple operation, high strength, stable connection quality and fast construction.
2. Heat shrinkable tape (sleeve) connection:
double-layer connection. Heat shrinkable tape (sleeve) is made by cross-linking polyolefin and reinforcing fiber. The inner layer uses heat shrinkable tape as the sealing layer and the outer layer as the reinforcing layer to ensure the connection Tightness and strength
Advantages: strong aging resistance, good sealing, strong tensile resistance of the joint, suitable for poor geological environments
1. Socket-type electric hot-melt connection:
(Some direct sockets and sealing rings do not change the material's temperature.) The socket and socket are prefabricated before the pipe leaves the factory, and the resistance wire is embedded in the inner wall of the socket. The electric fusion welding machine energizes the resistance wire, and the resistance wire heats up to cause the connection part to melt. The resin on both sides of the resistance wire interface is connected under the resin melting pressure, and the connection is achieved after cooling.
Advantages: good tightness, strong seal strength, even joint and pipe strength. Applicable to projects with good geological conditions or low pressure for water delivery.
2. Electrothermal fusion tape connection:
The principle of electric thermal fusion tape connection is the same as that of socket electric thermal fusion.
The difference is that the joints of the two pipes are flat mouths, which are similar to the shrink band connection. The difference is that only the electric heating tape is placed close to the pipe wall. Electric heating elements are added, and the hot melt tape and the outer wall of the pipe joint are heated and fused together.
Advantages: easy installation and use, low cost, high construction efficiency, tightly sealed joints without leakage, and good shear resistance.
Clamp type elastic connection:
This connection integrates rigid connection and flexible connection, the inner layer is sealed, and the outer layer uses stainless steel clamps to increase the strength of the interface
This type of connection is suitable for projects in various environments. It is not affected by the trench water level at the construction site and is easy to maintain. However, it requires a high degree of responsibility from the construction personnel, material factors, and the cost should be relatively high.
Note: According to the characteristics of the pipeline use project, the general hot-melt connection method is simple in construction and operation and suitable for pressureless drainage and small-diameter pipes; large-diameter pipes have a large heating area and long preheating time due to the heavy weight of the pipe itself. Disadvantages such as inconvenience in moving, it is recommended to use professional hot-melt connection and clamp connection with high efficiency and good sealing.
In addition to the above factors, the connection method of the pipeline will also be affected by geological effects. The uneven ground will be subsided due to ground subsidence. The pipeline itself and the gravity of the water in the pipeline will cause the pipe joints to stretch. Flexible connections are recommended: optional Heat-shrink tape (sleeve) connection, electric heating tape connection, or socket-type connection with sealing ring.