What does "DN25 PN16" mean?
PN said the pressure is, PN16 is the pipe can withstand 16MPa general meaning, namely, an 16 kg.
The welded steel pipe can be divided into thin-wall steel tube, ordinary steel pipe and thickened steel tube according to the thickness. Its nominal diameter is neither external diameter nor internal diameter, but a nominal size similar to the diameter of the ordinary steel pipe. Each nominal diameter corresponds to an outer diameter, and the inner diameter varies with the thickness. Nominal diameter can be expressed in metric mm, also available in English in. With nominal diameter pipeline accessories, meaning with tube. "DN25" means the inner diameter of the steel pipe is 25MM.
DN is nominal diameter, nominal diameter (or nominal diameter), that is, all kinds of pipe and pipe accessories of universal caliber. The same nominal diameter of the tube and pipe accessories can connect with each other, with interchangeability. It is not a real sense of the pipe diameter or diameter, although its value is closer with the pipe diameter or equivalent; in order to make the tube, pipe connection size uniform, with nominal diameter (also called nominal diameter, nominal diameter).
Steel pipe DN25, PN16, first of all, for this annotation: pipe DN class, often used in welded pipe, such as welded pipe DN25. PN16 means pressure, that is, 16 kilograms (1.6MPa).
