Patent ID: 7062954

Claim:
A leak detector comprising: a vacuum envelope ( 3 ); a vacuum pump( 5 ), which brings said vacuum envelope to a pressure substantially lower than ambient pressure; a membrane ( 7 ) being made of a material selectively permeable to a test gas separating at least a portion of said vacuum envelope from an external environment; a heater ( 9 ), which heats said membrane to a temperature at which the material of said membrane being permeable to the test gas; an electronic control unit ( 14 ) detecting current absorbed by said pump, the variation of the current being an indicator of diffusion of the test gas into said vacuum envelope; a probe ( 15 ), which intakes an ambient gas; a sampling pump ( 13 ), which sucks the ambient gas through said probe; a gas sampling line ( 11 a ) directing the ambient gas to said membrane; a discharge line ( 11 b ) exhausting the gas from said membrane via an exhaust port ( 19 ); and a switching system, which reverses an intake and an exhaust of the gas switching a working operation to a purging operation.