One、How to weld FRP pipes
1. Place a heating board coated with PTFE between the FRPP pipe and the welding surface of the FRPP pipe fitting.
2. Remove the heating plate when the surface to be welded reaches a specified temperature above its melting point, ensuring that the welding surface is in contact. Cool and solidify the joint under a certain pressure to achieve welding, which is known as hot plate welding.
3. The strength of welded joints depends not only on the weldability of the material and the design of the weld joint, but also on the parameters of the welding process.
4、Before operation, it is necessary to confirm the process parameters such as hot plate temperature, heating time, heating pressure, switching time, welding pressure, and welding holding time.
5. In principle, polymers that can be melted at a certain temperature without decomposition can be joined using hot plate welding. Hot plate welding machines with independently controlled temperatures can join different materials.
6. Among various welding methods, hot plate welding is the simplest and most convenient, offering high weld joint strength and excellent long-term performance.
Two. Connection methods and requirements for FRP pipes
1、FRRP pipe connection method
First, when the pressure is less than 0.6 MPa, the connection between the FRPP pipe and the existing pipe can be achieved using a coupling (also known as a pipe cap). Welding FRPP welding rods to both ends of the coupling is sufficient.
Secondly, when the pressure exceeds 0.6 MPa, the connection between the FRPP pipe and the existing pipe can be achieved using a weld-joint method, employing a hot-melt welding device with temperature control between 190°C and 205°C, followed by thorough cooling.
2、Requirements for connecting FRPP pipes
① The chemical composition of the welding rod material must ensure the required strength for welding FRP pipes.
② When using hot air welding, the heating temperature should comply with the following: 190-240℃; the welding rod and the welded surface must be clean and free of debris; the welding rod and the pipe material must be simultaneously melted to achieve welding, and there should be no signs of burning or decomposition; the welds should be closely spaced with no gaps; the weld surfaces should be smooth and free of ripples and weld bead protrusions; the strength of the welds should not be lower than the design specifications; the welds should cool naturally.
③ When welding pipes together using heat fusion, the temperature should be within the range of 190-240℃. Ensure that the connected pipes are horizontally fixed on the welding equipment's clamps, maintaining a level position and proper alignment. Use a welding device with adjustable temperature control. The welding temperature and time should be determined based on the pipe material. Maintain a sufficient welding force. The welding joint should naturally cool down.