Mfundo Yothandizira: Mukapatsidwa mphamvu, ma elekititic coulmatromagnetic amatulutsa mphamvu zamagetsi kuti akweze gawo la valavu, ndipo valavu imatsegulidwa; Mphamvu, mphamvu yamagetsi imazimiririka, kasupe kuti atseke kupsinjika pampando, valavu imatsekedwa. Mawonekedwe: Mu vacuum, kukakamizidwa kolakwika, kupanikizika konse kungagwire ntchito bwino, koma m'mimba mwake sikokwanira 25mm.
