cloche à vide

CONT: Contrôle d'étanchéité de soudure sur membrane bitumineuse au moyen d'une cloche à vide.

CONT: Seam Testing Methods... Vacuum chamber (boxes) have been used where a 3-ft- long box with a transparent top is placed over the seam and a vacuum of approximately 2.5 lb/in. superscript 2] applied. When a leak is encountered the soapy solution originally placed over the seam shows bubbles. These bubbles are due to air entering from beneath the liner and passing through the unbonded zone. The test is slow to perform and it is often difficult to make a vacuum-tight joint at the bottom of the box where it passes over the seam edges.