The Nominal Diameter of Sanitary Valves and Fittings
The nominal diameter is the dimension which represented by digital for all accessories in pipeline system, including stainless steel sanitary fittings and valves . Nominal diameter is a convenient rounded number for reference, is not only strict relationship with the machining dimension. Nominal diameter is “DN” followed by a digital symbol.
Nominal diameter is also called outside diameter. DN is nominal diameter, nominal diameter (or diameter), is the size of the general of variety of pipes.
The same nominal diameter of pipe and pipe fittings can be connected each other, are interchangeable. It is not on the actual meaning of pipe diameter or inner diameter, although its value with pipe diameter is relatively close to or equal, in order to make the pipe size, pipe connection is unified, the nominal diameter (also called nominal diameter and nominal diameter). Such as stainless steel welded steel pipe can be divided by the thickness of the thin wall steel, ordinary steel pipe and increasing pipe. Its nominal diameter is not outside diameter, also not inner diameter. It is a nominal size to approximate ordinary steel pipe inner diameter.
Each nominal diameter, corresponds to a diameter, its inner value varies with the thickness. Nominal diameter available metric mm said, also can use inch said. Sanitary fittings also expressed in nominal diameter, meaning is the same tube.
In general, the diameter of the pipes can be divided into outside diameter, inside diameter, nominal diameter. O.D for seamless stainless steel pipe diameter is represented by the letter D, followed by additional outer diameter size and wall thickness, such as diameter seamless steel pipe 108, a wall thickness of 5MM, D108*5, also with the outer diameter, such as De63 plastic pipe, and reinforced concrete pipe, cast iron pipe, galvanized steel pipe, said using DN, the design drawings in general with nominal diameter nominal diameter is represented, to a standard design and manufacture and repair convenience artificially specified, than the nominal diameter, tube (or pipe) specification name.
The nominal pipe diameter and the inner diameter, outer diameter are not equal, for example: nominal diameter DN100 of sanitary stainless steel seamless steel pipe is 102*2, 108*2 or other standard, 102mm is outer diameter of tube, 2mm is the wall thickness of the tube, therefore, the pipe diameter (102-2-2) = 98MM. But it is not completely equal to the difference of steel pipe diameter subtract double wall thickness. Also we can say, nominal diameter is a pipe specification name which close to the diameter, but not equal to the diameter. The design drawing with nominal diameter, the purpose is to determined structure size and connecting dimensions according to the nominal diameter of pipe fittings, valves, pipe flange, gasket, nominal diameter is represented by the symbol DN, if the diameter of said on the design drawings, also should make the piping specification table, show some pipe nominal diameter, wall thickness.
*The article was collected and revised by WELLGREEN PROCESS SOLUTIONS– Your reliable solutions of sanitary valves and fittings.