Kufotokozera: Valavu yotulutsa mpweya yothamanga kwambiri imaphatikizidwa ndi magawo awiri a valavu ya mpweya ya diaphragm yokhala ndi mphamvu yayikulu komanso valavu yolowera ndi yotulutsa mpweya yotsika, ili ndi ntchito zonse ziwiri zotulutsa mpweya ndi zolowetsa. Valavu yotulutsa mpweya ya diaphragm yokhala ndi mphamvu yayikulu imatulutsa mpweya wochepa womwe umasonkhanitsidwa mu payipi pamene payipiyo ili pansi pa mphamvu. Valavu yotulutsa mpweya yotsika komanso yotulutsa mpweya singathe kungotulutsa mpweya wokha...
Valavu yotchingira yotchingira yotchingira ndi mtundu wa valavu yotchingira yomwe imagwiritsidwa ntchito kwambiri m'mafakitale osiyanasiyana kuti ilamulire kuyenda kwa madzi. Ili ndi mpando wa raba womwe umapereka chisindikizo cholimba ndikuletsa kubwerera kwa madzi. Valavuyi idapangidwa kuti ilole madzi kuyenda mbali imodzi pomwe ikuletsa kuyenda mbali ina. Chimodzi mwazinthu zazikulu za mavavu otchingira otchingira otchingira otchingira ndi rabara ndi kuphweka kwawo. Ili ndi diski yolumikizidwa yomwe imatseguka ndikutseka kuti ilole kapena kuletsa madzi kulowa...