Apparatus and method for quantifying fluid loss in a closed system

A method for determining a rate of fluid loss from a nominally closed system across a test article comprising:

• A. providing a test article having a high pressure side and a low pressure side;
• B. providing a nominally closed system containing a fluid at a first pressure, wherein said nominally closed system is in fluid communication with the high pressure side of said test article and said nominally closed system is hermetically sealed except for said test article, through which said fluid may leak;
• C. providing a pressure controlled system having a second pressure that is lower than said first pressure, wherein said pressure controlled system is in fluid communication with the low pressure side of said test article;
• D. measuring and recording said first pressure as fluid leaks from said nominally closed system across said test article;
• E. adjusting said second pressure to maintain a predetermined pressure differential between said first pressure and said second pressure as the fluid leaks from said nominally closed system across said test article;
• and
• F. calculating the rate of loss of said fluid from said nominally closed system based upon a rate of change in said first pressure as the fluid leaks from said nominally closed system across said test article.

In a method for determining a rate of fluid loss from a nominally closed system through and/or around a test article having a high pressure side and low pressure side of a type using a pressure decay method with mass point leak rate analysis, an improvement test comprising:

• providing a controlled pressure system in fluid communication with the low pressure side of the test article;
• establishing a desired pressure differential between the nominally closed system and the controlled pressure system;
• maintaining the desired pressure differential as the fluid leaks from the nominally closed system through and/or around the test article;
• recording a temperature and pressure of the nominally closed system as the fluid leaks from the nominally closed system through and/or around the test article and periodically calculating the leak rate and measurement uncertainty;
• and
• terminating the test when either a predetermined measurement uncertainty level or test duration is reached.

An apparatus for determining a rate of fluid loss from a nominally closed system across a test article comprising:

• a test article having a high pressure side and a low pressure side;
• a microcontroller;
• a nominally closed system containing a fluid that has a first pressure and is in fluid communication with the high pressure side of said test article, wherein said nominally closed system further comprises:
• one or more pressure transducers in electrical or data communication with said microcontroller for measuring the pressure inside said nominally closed system and sending a signal to said microcontroller indicative of the pressure inside said nominally closed system;
• and
• one or more temperature sensors in electrical and/or data communication with said microcontroller for measuring a temperature inside said nominally closed system, wherein said nominally closed system is in fluid communication with the high pressure side of said test article;
• a pressure controlled system having a second pressure, wherein said pressure controlled system is in fluid communication with the low pressure side of said test article, and said second pressure is lower than said first pressure, thereby creating a predetermined pressure differential between said first pressure and said second pressure;
• and
• a means for controlling said second pressure to maintain the predetermined pressure differential as the fluid is lost from said nominally closed system across said test article,
• wherein said microcontroller calculates the rate of fluid loss across said test article based upon changes in said first pressure at said predetermined pressure differential and the temperature inside said nominally closed system.