Iyo sefa bag ndiyo moyo webhegi sefa panguva yekushanda. Kazhinji, iyo cylindrical pulse sefa bhegi inomiswa yakatwasuka mune inounganidza guruva. Guruva-rine gasi rinopinda munhonga huruva richibva mumhepo, ropfuura nemundiro yegwara remadota, uye mamwe makuru makuru ehuruva ari mugasi anopatsanurwa nekusagadzikana uye anowira zvakananga mugomba remadota. Guruva-rine gasi rinopinda munzvimbo yekusefa yebhegi rebhokisi rebhokisi. Yakawanda yeguruva inobatwa pamusoro pekunze kwesefa bhegi, uye gasi rakachena rinopinda mubhegi resefa kuburikidza nesefa zvinhu. Iyo gasi yakacheneswa inopinda mubhokisi repamusoro kuburikidza nesefa yebhegi port uye inoburitswa kubva mumhepo yekubuda. Keji iri mukati mebhegi resefa rinoshandiswa kutsigira bhegi resefa kudzivirira bhegi resefa kuti risadonha. Panguva imwecheteyo, inobatsira kubvisa uye kugovera keke yeguruva.