Self-diagnosing differential pressure flow meter including a directed pressure port

A flow metering apparatus for a fluid conduit, comprising:

• a fluid conduit having an obstruction body therein;
• a pressure port providing a high pressure signal;
• a pressure port providing a low pressure signal, the low pressure signal provided using the obstruction body;
• and
• an auxiliary pressure port providing an auxiliary pressure signal from a tap in a wall of the fluid conduit that is directed towards the obstruction body;
• wherein the pressure port providing a high pressure signal, the pressure port providing a low pressure signal, and the auxiliary pressure port providing an auxiliary pressure signal generate at least a primary differential pressure measurement signal and an auxiliary differential pressure measurement signal;
• further comprising meter electronics configured to:
• provide a baseline relationship between the primary differential pressure measurement signal and the auxiliary differential pressure measurement signal;
• and
• determine, at a later time, a second baseline relationship between the primary differential pressure measurement signal and the auxiliary differential pressure measurement signal.

A flow metering apparatus for a fluid conduit, comprising:

• a fluid conduit having an obstruction body therein;
• a pressure port providing a high pressure signal;
• a pressure port providing a low pressure signal, the low pressure signal provided using the obstruction body;
• a third pressure port providing an auxiliary pressure signal from a tap in a wall of the fluid conduit that is directed towards the obstruction body;
• wherein the pressure port providing a high pressure signal, the pressure port providing a low pressure signal, and the third pressure port providing an auxiliary pressure signal generate at least a primary differential pressure measurement signal and an auxiliary differential pressure measurement signal;
• and
• meter electronics configured to generate an indication responsive to determining that a relationship between the primary differential pressure measurement signal and the auxiliary differential pressure measurement signal has changed over time.