Isetshenziselwa ukupakisha ngemuva kwemikhiqizo yokwelashwa kwe-vacuum, ukuvimba umoya, i-vacuum yohlobo lokukhiyaumshini wokupakisha/inhlangano/umsebenzi ukhipha ngokuzenzakalelayo umoya ngaphakathi kwesikhwama, uye kulokho okulindelekile ngemva kwenqubo yokuvala i-vacuum ephelele.

