Umuyoboro w'icyuma ni ubwoko bw'icyuma gikozwe mu kuzunguruka umurongo w'icyuma mu buryo bw'umuyoboro ku mpande runaka ya spiral (gukora inguni) hanyuma ukayisudira. Ikoreshwa cyane muri sisitemu y'imiyoboro ya peteroli, gaze gasanzwe no kohereza amazi. Diameter ya nominal ni dia nominal ...