Method and apparatus of nondestructive testing a sealed product for leaks

A leak detection system for testing a sealed product for leaks, comprising:

• a test chamber comprising
• a receptacle dimensioned to receive said sealed product and to help prevent said sealed product from being destroyed from over expansion, and
• a cover dimensioned to operably seal said receptacle at an initial internal pressure when placed into position with said receptacle;
• a pressure system able to maintain a substantially constant pressure during a test period;
• and
• a leak sensor coupled to said test chamber via a first conduit and said pressure system via a second conduit, said leak sensor operable to
• permit gas flow between said test chamber and said pressure system via said first conduit and said second conduit,
• obtain a value representative of total mass of said gas flow between said sealed test chamber and said pressure system during said test period, and
• determine, based upon said value obtained for said total mass of said gas flow, whether said sealed product leaked an unacceptable amount during said test period, wherein said leak sensor comprises:
• a body comprising
• a first end portion operable to be coupled to said test chamber via said first conduit,
• a second end portion operable to be coupled to said pressure system via said second conduit, and
• a laminar flow gap developed between said first end portion and said second end portion that causes said gas flow through said body to exhibit substantially laminar flow characteristics during said test period;
• a differential pressure sensor
• connected to a first point and a second point of said laminar flow gap, and
• operable to generate a differential pressure signal that is representative of said differential pressure between said first point and said second point of said laminar flow gap;
• a temperature sensor operable to generate a temperature signal representative of temperature of said gas flow through said laminar flow gap;
• a static pressure sensor operable to generate a static pressure signal representative of static pressure developed by said gas flow trough said laminar flow gap, and
• a microcontroller connected to said differential pressure sensor, said temperature sensor, and said static pressure sensor and operable to
• calculate said value representative of said total mass of said gas flow between said sealed test chamber and said pressure system during said test period based upon said differential pressure signal, said temperature signal, and said static pressure signal, and
• determine, based upon said value obtained for said total mass of said gas flow, whether said sealed product leaked an unacceptable amount during said test period.

For use with a pressure system operable to maintain a substantially constant pressure during a test period and a sealed test chamber containing a sealed product, a leak sensor comprising:

• a body comprising
• a first end portion operable to be coupled to said test chamber via a first conduit,
• a second end portion operable to be coupled to said pressure system via a second conduit, and
• a laminar flow gap between said first end portion and said second end portion that causes gas flowing through said body to exhibit substantially laminar flow characteristics during said test period;
• a differential pressure sensor
• connected to a first point and a second point of said laminar flow gap, and
• operable to generate a differential pressure signal that is representative of said differential pressure between said first point and said second point of said laminar flow gap;
• a temperature sensor operable to generate a temperature signal representative of temperature of said gas flow through said laminar flow gap;
• a static pressure sensor operable to generate a static pressure signal representative of static pressure developed by said gas flow through said laminar flow gap;
• and
• a microcontroller connected to said differential pressure sensor, said temperature sensor, and said static pressure sensor and operable to
• calculate said value representative of said total mass of said gas flow between said sealed test chamber and said pressure system during said test period based upon said differential pressure signal, said temperature signal, and said static pressure sensor;
• and
• determine, based upon said value obtained for said total mass of said gas flow, whether said sealed product leaked an unacceptable amount during said test period.