摘要 |
A method for butt welding first and second thermoplastic pipes to each other including the steps of locating the end portions of first and second pipes to be joined in clamps that are moveable towards and away from each other by the application of hydraulic pressure, the pipe end portions being moveable against a facer for trimming the pipe ends at a first predetermined optimum hydraulic pressure, moveable against a heater for heating the pipe ends to a molten state at a second predetermined optimum hydraulic pressure and moveable towards each other while the ends are in a molten state to fuse the pipes at a third predetermined optimum hydraulic pressure, determining the hydraulic pressure required to move the pipe end portions towards each to determine a drag force hydraulic pressure, adding the drag force hydraulic pressure to each predetermined optimum hydraulic pressure to obtain first, second and third operating hydraulic pressures, and butt welding the pipes to each other using the first, second and third determined operating hydraulic pressures. <IMAGE> |