8 Commonly Used Connection Methods for Pipelines

Pipeline commonly used connection methods include: threaded connection, flange connection, welding, groove connection (clamp connection), socket connection, crimp connection, heat fusion connection, and socket insertion connection.

Flange Connection

Flange connection is used for larger diameter pipes. It is generally used to connect valves, check valves, water meters, water pumps, etc., on main pipelines, as well as on pipe sections that require frequent disassembly and maintenance. If galvanized pipes are welded or flanged, the welded area should undergo secondary galvanizing or corrosion protection.

Welding

Welding is suitable for non-galvanized steel pipes and is mostly used for concealed piping and larger diameter pipes, commonly used in high-rise buildings. Copper pipe connections can be made using specialized fittings or welding. Socket welding or sleeve welding is suitable for pipe diameters less than 22mm, with the socket facing the direction of flow. Butt welding is suitable for pipe diameters greater than or equal to 22mm. Stainless steel pipes can be welded by socket insertion.

Threaded Connection

Threaded connection utilizes pipe fittings with threads. Galvanized steel pipes with a diameter less than or equal to 100mm are suitable for threaded connections, commonly used in exposed piping. Steel-plastic composite pipes are also generally connected by threaded connections. Galvanized steel pipes should be connected by threaded connection, and the surface of the damaged galvanized layer and exposed threaded parts during threading should be treated with corrosion protection. Flange or socket-type specialized pipe fittings should be used for connection, and the welded area between galvanized steel pipes and flanges should undergo secondary galvanizing.

Socket Insertion Connection

Used for connecting water supply and drainage cast iron pipes and fittings. There are two types: flexible connection and rigid connection. Flexible connections use rubber ring seals, while rigid connections use asbestos cement or expansive filler seals. Lead seals can be used in important situations.

Socket Connection

The aluminum-plastic composite pipe generally uses threaded socket pressure connection. The nut of the fitting is placed on the end of the pipe, and then the inner core of the fitting is inserted into the end of the pipe. The fitting and nut are tightened with a wrench. Copper pipes can also be connected using threaded socket pressure connections.

Crimp Connection

Stainless steel crimp fittings have replaced traditional water supply pipeline connection technologies such as threading, welding, and adhesive bonding. They have features such as protecting water quality and hygiene, strong corrosion resistance, and long service life. During construction, the socket fittings with special sealing rings are connected to the pipeline, and the socket is tightly sealed and fastened with special tools. The construction has the advantages of convenient installation, reliable connection, and economical rationality.

Heat Fusion Connection

The connection method of PPR pipes uses a hot fusion machine for heat fusion connection.

Groove Connection (Clamp Connection)

Groove-type connection fittings can be used for firefighting water, air conditioning hot and cold water, water supply, rainwater, etc., with a diameter greater than or equal to 100mm of galvanized steel pipes. They have the characteristics of simple operation, not affecting the original characteristics of the pipeline, safe construction, good system stability, convenient maintenance, labor, and time-saving.