Kufotokozera Kwachidule:

3 njira pulagi valavu  ndi chidutswa chotsekera kapena chozungulira chozungulira chozungulira, potembenuza madigiri 90 kuti doko likhale pa pulagi ya valavu ndi thupi la valavu lofanana kapena losiyanitsa, kutsegula kapena kutseka valavu. Pulagi ya valavu ya pulagi itha kukhala yoyendera magetsi kapena yozungulira. M'mapulagi ozungulira, njira nthawi zambiri zimakhala zazing'ono; Mu pulagi yamagetsi, njirayo ndi trapezoidal. Akalumikidzidwa izi zimapangitsa kapangidwe ka pulagi valavu opepuka, koma pa nthawi yomweyo kupanga imfa zina. Valavu yamapulagi ndiyabwino kwambiri kudula ndikulumikiza sing'anga ndikusintha, koma kutengera mtundu wa ntchitoyo komanso kukokoloka kwa malo osindikiza, nthawi zina itha kugwiritsidwanso ntchito. Chifukwa kuyenda pakati pa kusindikiza pamwamba pa valavu yamapulagi kumatha kupukuta, ndipo ikatseguka kwathunthu, imatha kuletsa kuyanjana ndi sing'anga, kotero itha kugwiritsidwanso ntchito ngati sing'anga wokhala ndi ma tinthu oimitsidwa. Chinthu china chofunikira pa valavu yamapulagi ndikosavuta kwake kusintha kuti igwirizane ndi njira zingapo, kuti valavu izitha kukhala ndi njira ziwiri, zitatu, kapena zinayi. Izi zimapangitsa kuti mapaipi azikhala ochepa, amachepetsa kugwiritsa ntchito ma valve, komanso amachepetsa zovekera zomwe zimafunikira pazida.

NYANJA ndi mmodzi wa kutsogolera China 3 njira pulagi valavu   Wopanga & Wogulitsa.