DIAGNOSTIC MODULE Russian patent published in 2002 - IPC

FIELD: tests of articles for tightness. SUBSTANCE: diagnostic module to test tightness of tank, ventilation system of fuel tank of vehicle in particular, has reference leak 15 which is designed for passage of flow with specified volumetric flow rate through it and is matched to permissible value of leak from tank. In proposed diagnostic module reference leak 15 is formed by several diaphragms 22-24 placed in sequence, each having one throttling hole 25-27. Advantage of this diagnostic module lies in possibility of making throttling holes 25- 27 of bigger diameter as compared with substantially smaller diameter of hole of permissible leak which makes them less sensitive to effects of various influences. EFFECT: lesser sensitivity of diagnostic module to effects of various influences. 6 cl, 4 dwg