Device and method for testing differential pressure measuring passageways

A device for detecting leaks in the differential pressure measuring passageways of an orifice meter tube, the orifice meter tube being designed to be inserted into a pipeline used for custody transfer of gaseous fluids, the meter tube having an orifice fitting holding an orifice plate which is installed within the orifice fitting within the meter tube perpendicular to the flow of fluid therein, the differential pressure measuring passageways being located on either side of the orifice plate within the meter tube, the leak detecting device comprising:

• a body having an externally threaded end region which is adapted to threadedly engage a mating internally threaded region of the differential pressure measuring passageway which is to be tested, the body having an internal bore therethrough;
• an elongate stem adapted to be slidingly received within the internal bore of the body when the body is engaged within the differential pressure measuring passageway, the elongate stem having an exposed end which extends externally from the body and an inner end insertable through the internal bore of the body at least partially the length of the differential pressure measuring passageway;
• a packing cap received on the end of the body through which the exposed end of the stem extends for sealing the internal bore of the body;
• a testing port located on the body external to the pressure measuring passageway when the body is engaged within the passageway and communicating with the internal bore of the body for connection of testing equipment;
• and
• seal means located on the inner end of the elongate stem actuatable by manipulation of the elongate stem to seal off the opening of the differential pressure measuring passageway into the orifice fitting and form a sealed chamber between the packing cap and the stem inner end which communicates with the testing port for testing the integrity of the passageway.

A method for detecting leaks in the differential pressure measuring passageways of an orifice meter tube, the orifice meter tube being designed to be inserted into a pipeline used for custody transfer of gaseous fluids, the meter tube having an orifice fitting holding an orifice plate which is installed within the orifice fitting within the meter tube perpendicular to the flow of fluid therein, the differential pressure measuring passageways being located on either side of the orifice plate within the meter tube the method comprising the steps of:

• installing a body having an externally threaded end region into a mating internally threaded region provided in the differential pressure measuring passageway which is to be tested, the body having an internal bore therethrough;
• providing an elongate stem within the internal bore of the body, the elongate stem having an exposed end which extends externally from the body and an inner end insertable through the internal bore of the body at least partially the length of the differential pressure measuring passageway;
• providing the body with packing on the end of the body through which the exposed end of the stem extends for sealing the internal bore of the body;
• manipulating the elongate stem to actuate seal means provided on the inner end of the stem to seal off the opening of the differential pressure measuring passageway into the orifice fitting;
• and
• connecting test equipment to a test port provided on the body external to the pressure measuring passageway which communicates with the internal bore of the body and, in turn, the passageway for testing the integrity of the passageway.