Abstract: A combined temperature and pressure sensing probe assembly for a flow measurement system comprising a body, a portion of which is adapted for insertion into fluid flowing in a confined conduit, such as a pipe. Within the body are separated plenums which are exposed respectively to high and low fluid pressures in the flow. A manifold block is that portion of the body which is disposed outside of the pipe containing the fluid flow. Along with valves and fluid conveying channels, the block is equipped with a duct for carrying electrical conductors and also contains a traversing bore which is aligned with the body and is in communication with the conductor carrying duct. An electrically responsive temperature sensor is disposed within or formed from the body. Conductors from the temperature sensor are directed from the manifold's bore through the connecting duct to a point exterior of the manifold.

Abstract: An ultrasonic flow meter (10) has a pair of transducers (36, 38). A first (36) of the pair of transducers is coupled to a first divider (18) having a first predetermined divisor. A second (38) of the pair of transducers is coupled to a second divider (24) having a second predetermined divisor. The second predetermined divisor is not equal to the first predetermined divisor. An input (16) of the first divider (18) is coupled to a first oscillator (12). An input (22) of the second divider (24) is coupled to a second oscillator (14). A decoder circuit (50) is coupled to an output (15) of the first oscillator (12) and an output (20) of the second oscillator (14). The decoder circuit (50) determines a difference frequency.

Abstract: An apparatus (300) for detecting an ultrasonic signal (304) has a transducer (302) that produces an electrical signal (306) in response to the ultrasonic signal (304). A threshold comparator (308) receives the electrical signal (306) and produces a phase one signal (310) and a phase two signal (312). An arming circuit (314) receives the phase one signal (310) and the phase two signal (312) and producing an arming signal. A triggering circuit (316) receives the arming signal and the electrical signal (306) and produces a signal detected signal (318).

Abstract: A fluid pressure and temperature sensing probe assembly for a mass flow measurement system comprising, a tubular body, a portion of which is adapted for insertion into the fluid flowing in a confined conduit, and having, within the body, a pair of separated plenums. Openings are provided in the tubular body which expose the respective plenums to high and low fluid pressures in the fluid flow. An electrically responsive temperature sensor, having an electrical signal output, is disposed within the tubular body of the probe. A pressure transducer, in fluid communication with the plenums, converts the fluid pressures in the plenums to at least one electrical signal representative of the difference between the high and low fluid pressures. A transmitter transmits the electrical signal from the pressure transducer and the electrical temperature signal to a remote location.

Abstract: An apparatus for controlling a voltage controlled oscillator (20) in an ultrasonic flow meter (18) includes a comparator (28) for comparing a received signal to an estimate signal, to form an early-late signal (32). The early-late signal (32) is received by a counter (36) to form a count signal (38). A digital to analog converter (42) receives the count signal (38) and converts it to a control voltage output (40) that is coupled to the voltage controlled oscillator (20).

Abstract: An apparatus for determining a flow count in an ultrasonic flow meter has an upstream oscillator (22) with an upstream signal (24) having a period proportional to an upstream transit time and a downstream oscillator (26) with a downstream signal (28) having a period proportional to a downstream transit time. The upstream signal (24) is coupled to a positive increment input (30) of a counter (32) and the downstream signal (28) is coupled to a negative increment input (36) the counter (32).

Abstract: In a flow measurement system comprising a primary flow sensor and a secondary electronic conversion apparatus for converting high and low fluid pressure signals from the primary flow sensor to an electronic signal output representative of fluid flow, a process for calibrating the system as an integral unit, comprising the steps of applying a plurality of known reference fluid flow rates to the primary flow sensor over the system's operative range of flow conditions, sensing the electrical output of the secondary electronic conversion apparatus for each of the said plurality of reference fluid flow rates, establishing a correction factor for each of said recorded values of electrical output which will tend to linearize the relationship between fluid flow rate and the electrical output of the measuring system, and storing the correction factors in non-volatile memory in a microprocessor which is part of the secondary electronic conversion apparatus.

Abstract: A method of detecting and aligning a signal in an ultrasonic flow meter (18) generates an oscillator signal (50) and a transmit sequence (54) on a first predetermined trigger point (55) of the oscillator signal (50). The transmit sequence (54) is used to drive a transmit transducer (14, 16) to form a transmit waveform (60). The transmit waveform (60) is received by a receive transducer (14, 16) to form a received waveform. The received waveform is processed to form a received sequence (62). The received sequence (62) is then processed to sense an anomaly (80).

Abstract: A method of detecting a signal (50) in an ultrasonic flow meter sets a first threshold (52) and a second threshold (54) at a predetermined level above the first threshold (52). An ultrasonic signal (50) having a plurality of cycles is then received. Next it is determined when the ultrasonic signal (50) exceeds the first threshold (52). This time is marked a first threshold time. Then it is determined when the ultrasonic signal exceeds the second threshold (54). This time is marked a second threshold time. A time difference between the first threshold time and the second threshold time (56) is determined. When the time difference (56) exceeds a delta time, increasing the first threshold (52) a delta level.