Icebo lokucoca ulwelo lwe-SGF lenziwe ziifilter ezimbini ezityiweyo, ivelufa yokujonga, ivelufa yokuqondisa kunye nesalathi. Kuya kufuneka ifakwe kwindawo yokuphuma yomgca woxinzelelo oluphezulu. Inqaku leli cebo lokucoca livumela ukusebenza okuqhubekekayo nangexesha lokutshintsha into, evalwe ngengcoliseko. Xa uxinzelelo lwento evalekileyo engcolileyo ifikelela kwi-0.5Mpa, isalathiso sinika imiqondiso ebonisa ukuba into kufuneka itshintshwe. Ngeli xesha, jika i-valve yesikhombisi, yeka enye icebo lokucoca ulwelo, kwaye utshintshe into evaliweyo. Ukuba into ayinakutshintshwa ngexesha de uxinzelelo lufike kwi-0.6Mpa, ivelufa yokudlula iya kuvula ngokuzenzekelayo ukugcina ukhuseleko lwenkqubo.