Isebenza ohlelweni lokuthambisa uwoyela namafutha, uwoyela ungalungiswa ngokuzenzakalelayo, futhi indawo ngayinye yokukhipha uwoyela inikezwa i-valve yokuhlola ukuvimbela uwoyela ukuthi ungachithi. iphampu yokugcoba amafutha enziwe ngesandla.
