Production Process of Polyurethane Insulating Pipe
There are three main production processes for polyurethane insulating pipes: "one-step method", "pipe-in-pipe method" and "foam spray method". The "one-step method" is mainly used for steel pipes with a pipe diameter less than DN500. The process is limited with the pipe diameter range: the larger the pipe diameter, the difficulty of forming the insulation layer at one time will increase, and the eccentricity problem will become more serious. . The "pipe-in-pipe method" is suitable for various pipe diameters, and the formation and eccentricity of the insulation layer are easier to control than the "one-step method". However, the process is more complicated, the foam density is uneven, the cavity is large, and it is difficult to make a large diameter outer protective tube. "Foam spraying method" is a new type of process, using foam spraying equipment to spray polyurethane foam on the surface of the steel pipe directly,...