One, the metric system that the imperial conversion making a way that is nominal diameter becomes millimeter also can be nominal diameter only makes a way, cannot corresponding external diameter, because the pipe of same nominal diameter returns the branch that has size line of action

2, formulary without absolutely conversion on the norms of conduit, calculate to be less than 100 to be able to blur with 1 =25, take the number of its close, use 1 =25 to be able to match computation completely to be more than the pipe of 100. Be as follows commonly usedly:

The common of correspondence of nominal diameter DN6 says 1 minute

The common of correspondence of nominal diameter DN8 says 2 minutes

The common of correspondence of nominal diameter DN10 says 3 minutes

The common of correspondence of nominal diameter DN15 says 4 minutes

The common of correspondence of nominal diameter DN20 says 6 minutes

The common of correspondence of nominal diameter DN25 weighs 1

The common of correspondence of nominal diameter DN32 weighs 1 2 minutes

The common of correspondence of nominal diameter DN40 weighs 1 half

The common of correspondence of nominal diameter DN50 weighs 2

The common of correspondence of nominal diameter DN65 weighs 2 half

The common of correspondence of nominal diameter DN80 weighs 3

The common of correspondence of nominal diameter DN100 weighs 4

The common of correspondence of nominal diameter DN125 weighs 5

The common of correspondence of nominal diameter DN150 weighs 6

The common of correspondence of nominal diameter DN200 weighs 8

The common of correspondence of nominal diameter DN250 weighs 10

The common of correspondence of nominal diameter DN300 weighs 12

The common of correspondence of nominal diameter DN350 weighs 14

The common of correspondence of nominal diameter DN400 weighs 16

The common of correspondence of nominal diameter DN450 weighs 18

The common of correspondence of nominal diameter DN500 weighs 20

The common of correspondence of nominal diameter DN600 weighs 24

Flower cent of =8 of millimeter of 1 inch of =25.4

1/2 is 4 minutes (4 flower cent) 1.27cm of DN15 ＝

3/4 is 6 minutes (6 flower cent) 1.905cm of DN20 ＝

The meaning of De, DN, D, D, Φ

1, DN (Nominal Diameter) the nominal diameter of means conduit, it is the average of external diameter and internal diameter. The is worth =De value of DN – ply of 0.5* tube wall. Attention: This both neither is external diameter also not be internal diameter.

Water, gas carry steel tube (galvanization steel tube or blame galvanization steel tube) , multiple tube of model of cast-iron pipe, steel and pvc (PVC) the tubal material such as the canal, should tag nominal diameter ” DN ” (like DN15, DN50) .

2, De (External Diameter) means conduit external diameter, canal of PPR, PE, polypropylene is in charge of external diameter, use De to tag commonly, all need to tag the form with large wall of external diameter * , exemple De25 × 3.

3, D points to conduit internal diameter commonly.

4, D points to the diameter inside concrete canal commonly. Ferroconcrete (or concrete) the tubal material such as canal of canal of canal, argil canal, acid-proof pottery and porcelain, a compound of sand, d of diameter of less than of appropriate tubal way expresses (wait like D230, D380) .

5, the diameter that Φ expresses common circle; Also can express to be in charge of the external diameter of material, but should multiplying ever since right now with the wall thick. Be like: 25 × of Φ 3, express external diameter 25mm, the wall is large the tubal material that is 3mm. To seamless steel tube or nonferrous metal conduit, should tag ” wall of external diameter × is large ” . For example 108 × of Φ 4, Φ can omit. China, ISO and standard of Japanese part steel tube use mural large size to represent thick set of steel tube wall. To the expression of norms of this kind of steel tube the method is a canal wall of external diameter × is large. For example 60.5 × of Φ 3.8.