What is the relation between MM and IN for valve diameter?1 inch is equal to DN25?

The diameter specification conversion of the valves is often used in daily work, which is the conversion of the commonly used American standard(API or ANSI) valve diameter and the national standard(GB) valve diameter. Now, we are going to make a table for some commonly used American standard diameter and national standard diameter, so that more users can have a clear idea about the relationship between American standard diameter and the national standard diameter. The unit for the nominal diameter in national standard is millimeter,MM in short; the unit for nominal diameter in American standard is Inch, IN in short. 

1 inch is equal to 25.4mm, so for the diameter, 1 inch in American standard is equal to DN25mm in National standard; 

Valve diameter size in GB(MM)	Valve diameter size in API/ANSI(Inch)
DN15	1/2″
DN20	3/4″
DN25	1″
DN32	1 1/4″
DN40	1 1/2″
DN50	2″
DN65	2 1/2″
DN80	3″
DN100	4″

Belo Valve can manufacture industrial valves products like butterfly valves series, hydraulic control valves series, soft-seal gate valves series, hard-seal gate valves and globe valves series, fire protection valves series, check valve series, expansion joints series, rubber joints, stainless steel bellows expansion joints, with over 30 series and more than 1000 specifications, with nominal diameters ranging from DN15-DN1200, pressure class ranging from 0.6Mpa-6.4Mpa. Belo valves are mainly fabricated with material gray cast iron and ductile cast iron, with standards like German standard(DIN), American standard(API,ASME B16.34), ISO, GB, or customer’s special requirements. Our valves products are widely used in water supply and drainage piping systems, water heating piping systems, fire protection systems, drinking water piping systems, municipal works, chemical engineering, metallurgical industry, dust removal systems, pharmacy industry,etc, and have been exported to Southeast Asia, Middle-east, Africa, America, Russia, and some countries in Europe. 

For more information or price about different diameter valves, please contact us: