Duba bawuloli, bawuloli marasa dawowa, an ƙera su don hana juyawar kwarara a cikin tsarin bututun.Ana kunna waɗannan bawuloli ta hanyar kayan da ke gudana a cikin bututun.Matsin ruwan da ke wucewa ta tsarin yana buɗe bawul, yayin da duk wani juzu'i na gudana zai rufe bawul.Ana cika rufewa ta hanyar nauyin injin dubawa, ta matsa lamba na baya, ta hanyar bazara, ko ta hanyar haɗin waɗannan hanyoyin.

Babban Shigarwa Duba Valveƙira da ƙira bisa ga ASME B16.34, gwaji da dubawa zuwa API598, API6D.

Bawul ɗin rajistan shiga sama yana da wurin zama, keji, diski da bonnet mai cirewa yana amfani da haɗin zaren wurin zama da mating counterbore a cikin jikin bawul don hana motsin wurin zama, keji da diski a cikin hanyar ƙasa.Kafada ta annular a cikin jikin bawul tana hana motsin wurin zama, keji da fayafai a sama.