The elbow ne bututun da ke canza shugabanci na bututun. Da kusurwa, akwai 45 ° da 90 ° 180 ° uku mafi yawan amfani, kuma bisa ga buƙatun injiniya sun haɗa da sauran kusurwa masu ban mamaki kamar 60 ° da sauransu. Abubuwan da za a iya amfani da su ne karfe, bakin karfe, karfe mai haɗin gwiwa, karfe mai ƙarfe, karfe mai carbon, karfe mai launi da filastik da sauransu. Hanyoyin haɗi tare da bututun sune: kai tsaye walda (mafi yawan hanyar amfani) flange haɗi, zafi narkewa haɗi, lantarki narkewa haɗi, thread haɗi da kuma bearing irin haɗi da sauransu. Dangane da samar da tsari za a iya rarraba zuwa: walda rukuni, hatimi rukuni, turawa rukuni, jefa rukuni, walda rukuni, da dai sauransu. Sauran sunayen: 90 digiri kullun, madaidaiciya kullun, ƙauna da kullun da sauransu.

Ana iya rarraba ta hanyar samarwa zuwa tura, matsa lamba, ƙirƙirar, jefa, da dai sauransu.

Za a iya rarraba ta hanyar masana'antu misali zuwa misali na kasa, alamar lantarki, alamar jirgin ruwa, alamar sinadarai, alamar ruwa, alamar Amurka, alamar Jamus, alamar rana, alamar Rasha, da dai sauransu.

Raba ta hanyar radius na curvature: za a iya raba shi zuwa dogon radius elbow da gajeren radius elbow. Long radius elbow nufin da radius na curvature daidai da 1.5 sau na waje diameter na bututun, watau R = 1.5D; Short radius elbow yana nufin radius na curvature daidai da diamita na waje na bututun, watau R = 1.0D. (D shine diamita na rukuni, R shine radius na curvature).

Idan aka rarraba ta hanyar matsin lamba: akwai kimanin nau'ikan goma sha bakwai, da kuma bututun Amurka daidai ne, akwai: Sch5s、Sch10s、Sch10、Sch20、Sch30、Sch40s、STD、Sch40、Sch60、Sch80s、XS; Sch80、SCH100、Sch120、Sch140、Sch160、XXS; Biyu daga cikin waɗanda aka fi amfani da su ne STD da XS.

Dangane da daban-daban siffofin amfani za a iya raba zuwa: rukuni irin rukuni, katin layi irin rukuni, biyu bearing rukuni, flange rukuni, diameter rukuni, zama rukuni, ciki da waje hakora rukuni, hatimi rukuni, tura rukuni, bearing rukuni, welding rukuni, ciki waya rukuni, da dai sauransu.