Umuyoboro udafite ibyuma, nkuko izina ribigaragaza, ni umuyoboro udafite ikidodo cyangwa icyuma gisudira.Imiyoboro idafite ibyuma ni igice cyigituba cyangwa silindari idafite umwobo, mubisanzwe ariko ntabwo byanze bikunze byambukiranya uruziga, bikoreshwa cyane cyane mugutanga ibintu bishobora gutemba -ibisukari na gaze (fluide), ibishishwa, ifu, ifu nimbaga ya solide nto.Umusaruro wibyuma byacu bidafite kashe bigenzurwa cyane kandi imiyoboro yose twakoze yageragejwe byuzuye mubipimo mpuzamahanga kugirango tumenye gusa ibicuruzwa birebire cyane.