Ubudlelwane phakathi kweenkcazo ze-DN, φ ne-intshi.

Yintoni "i-intshi": i-intshi (") yiyunithi yenkcazo yaseMelika, enje ngemibhobho yentsimbi, iivalves, iflethi, iimpompo, iimpompo, njenge-10".

Intshies (i-intshi, ifinyezwe njengakuyo.) Kuthetha isithupha kwiDatshi, kunye ne-intshi enye ubude besithupha. Ewe, ubude besithupha somntu bukwahlukile. Kwinkulungwane ye-14, uKumkani uEdward II wakhupha "i-intshi yezomthetho".

Icacisiwe ukuba ubude beziinkozo ezintathu ezinkulu ezikhethwe ukusuka embindini weRarley kwaye zicwangciswe ngokulandelelana yi-intshi enye.

Ngokubanzi 1 "= 2.54Cm = 25.4mm

Yintoni i-DN: I-DN yiyunithi esetyenziswayo esetyenzisiweyo kwi-Chinese nakwiinkqubo zaseYurophu. Ikwayinto ekwakukuchazwa kokuchonga imibhobho, iivalve, flames, i-pumps elungele kunye neempompo, njenge-DN250.

I-DN ibhekisa kububanzi obubekiweyo bombhobho (okwaziwa ngokuba yidayamitha), Qaphela: Lo asingobubanzi bangaphandle okanye ububanzi bezinto zangaphandle, kungumndilili ophakathi, obizwa ngokuba ngumndilili wangaphakathi.

Yintoni iyunithi ngokubanzi, ebhekisele kububanzi bemibhobho yemibhobho, i-ellows, intsimbi ejikelezileyo kunye nezinye izinto. Ingatsho ukuba ibe bububanzi. Umzekelo, φ609.6mmme ubhekisa kububanzi bangaphandle abangama-609.6mm.

Ngoku sifumene ukuba zifanekisela ntoni ezi yunithi zintathu, lunjani lonxibelelwano phakathi kwabo?

Okokuqala, "intsingiselo ye" DN "iphantse yafana ne-DN, ngokusisiseko ithetha ububanzi bendawo, ebonisa ubungakanani beli nkcazo, kwaye φ kukudibanisa zombini ezi nkcazo.

Umzekelo: Ukuba umbhobho wentsimbi yi-DN600, kwaye umbhobho wentsimbi olwenziwe nge-intshi, iba yi-24 ". Ngaba lukhona uqhagamshelo phakathi kwezi zimbini?

Impendulo ngu-ewe! I-intshi jikelele iphindaphindwe ngokuthe ngqo kwenani elipheleleyo ngama-25, elilingana ne-DN, elinjenge-1 "* 25 = 25 = DN100 njalo njalo.

Ewe kunjalo, kukho izinto ezifanayo, ezinje nge-3 "* 25 = 75, kwaye i-intshi ezinokubalwa njenge-Imicolons okanye i-1/2"

1/2 "= DN15 3/4" = DN20 1-1 / 4 "1