Ultrasonic flow meter with a liquid drainage system

A method for draining an accumulated liquid from a transducer port of an ultrasonic flow meter, the method comprising:

• (a) flowing a fluid through a throughbore in the flow meter, wherein the transducer port extends from the throughbore and is in fluid communication with the throughbore;
• (b) communicating an acoustic signal across a throughbore of the flow meter with a transducer disposed in the transducer port;
• (c) accumulating a liquid in the transducer port during (a);
• (d) draining the accumulated liquid in the transducer port through a drain port in fluid communication with the transducer port after (c);
• (e) flowing the liquid from the drain port into a drain conduit during (d);
• (f) biasing a valve in the drain conduit to a closed position restricting the liquid from flowing through the valve;
• and
• (g) transitioning the valve to an open position after (c) to allow the liquid to flow through the valve.

A method for identifying a malfunctioning acoustic transducer in an ultrasonic flow meter, the method comprising:

• (a) flowing a fluid through a throughbore of the flow meter;
• (b) sending an acoustic signal across a throughbore of the flow meter with an acoustic transducer disposed in a transducer port extending from a throughbore in the flow meter;
• (c) receiving an acoustic signal passing across the throughbore of the flow meter with the acoustic transducer;
• (d) providing a drain port in fluid communication with the transducer port, wherein a drain conduit coupled to the drain port includes a valve;
• (e) continuously monitoring the acoustic signals with an electronics package coupled to the transducer;
• (f) determining the validity of the acoustic signals with the electronics package during (e);
• (g) maintaining the valve in the closed position with the electronics package when the acoustic signal is determined to be valid in (f);
• (h) transitioning the valve to the open position in (g) with the electronics package when the acoustic signal is determined to be invalid in (f).