What does "DN PN" mean? DN25 PN18 stands for what is the thickness? With the usual said 4 in charge of what's the relationship?
PN nominal pressure.Definition：Relating to the mechanical and dimensional characteristics of the components of the piping system and the identification of letters and combinations of numbers for reference. It consists of letters PN and followed by dimensionless numbers.Note 1: numbers followed by letters "PN" do not represent measurements and are not used for purposes of calculation unless otherwise specified in the relevant standards.Note 2: is not associated with the relevant pipe component standards, but the term "PN" does not make sense.Note the 3: piping element allows the pressure to depend on the PN value of the element, the material and design, and allows the operating temperature, etc., to allow the pressure to be given in the corresponding standard pressure temperature class table.Note 4: all pipe elements with the same PN and DN values shall have the same mating dimensions as their flanges.The latest definition of PN comes from standard GB/T 1048-2005, the definition and selection of pipe component PN (nominal pressure), and is referenced in the standard of pipe fittings and tubing. GB/T 1048-2005 7268:1996 Pipe components - modified ISO/CD Definition of nominal pressure, a "note increase than the original standard: allow numerical" choose other PN when necessary, namely in the PN series, you can use other numerical PN.
*DN25 nominal diameter 25MM*PN18 nominal pressure 18 kg / cm2
Nominal diameter (nominal, diameter), also known as the average diameter (mean, outside, diameter).DN is nominal diameter, nominal diameter (or nominal diameter), that is, all kinds of pipe and pipe accessories of universal caliber. The pipes with the same nominal diameter can be connected with each other, so they are interchangeable. It is not the actual diameter or diameter of the pipe, although its value is close to or equal to the diameter of the pipe.In order to connect the pipe and pipe fittings in a unified way, nominal diameter (also called nominal diameter, nominal diameter) is adopted. For example, welded steel pipes can be divided into thin wall steel pipes, ordinary steel pipes and thickened steel pipes according to their 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.Nominal outer diameter is expressed by DN, refers to the outer diameter of the pipe. Such as the outer diameter of 32mm PVC-U pipe can be expressed as dn32. The specification of PVC-U pipe for building drainage is indicated by DN (nominal outer diameter) * e (pipe wall thickness) (GB-T, 5836.1-2006).
