Bestobell Sparling Ltd.

Rodney C Johnson

Alvin E Brown

An interface system (5) for connection to a fluid flow monitoring assembly is described. The monitoring assembly comprises a signal generating assembly and a signal receiving assembly (8,9) for transmitting signals into a flowing fluid and for receiving the signals after transmission through the fluid respectively; and a monitoring assembly (1) for controlling the transmission of signals by the signal generating assembly, sensing the signals received by the signal receiving assembly, and thereby monitoring the fluid flow. The signal generating and receiving assemblies (8,9) are adapted to transmit and receive signals passing through the fluid along at least two paths and the monitoring assembly (1) has one communication port for each transmission path. The interface system (5) comprises first and second converting assemblies linked by a common signal path (6), the first converting assembly (4) being connectable with the communication ports and the second converting assembly being connectable to the signal generating and receiving assemblies (8,9). The converting assemblies (4,7) are arranged to pass first signals along the signal path (6) in response to the receipt of signals from the communication ports or from the signal receiving assembly respectively, the first converting assembly (4) being responsive to first control signals to cause signals corresponding to signals received from the common signal path (6) to be passed to appropriate ones of the communication ports, and the second converting assembly (7) being responsive to second control signals to cause signals to be transmitted into the fluid by the signal generating assembly along appropriate paths.

Fluid flow monitoring

A method and an apparatus for (a) monitoring fluid flow by transmitting acoustic signals in opposite directions through a fluid with components in the direction of flow; (b) receiving the transmitted signals; (c) providing a first signal representing acoustic velocity; (d) time-integrating the first signal to produce a ramp signal, the rate of change of which represents acoustic velocity in the fluid; (e) transmitting a first acoustic signal in one direction through a fluid; (f) transmitting a second acoustic signal in the opposite direction through the fluid; and (g) initiating integration of the first signal. The ramp signal is compared with a second signal representing fluid flow velocity to generate first and second arrival signals according to the direction of the transmitted acoustic signal; expected arrival times for the transmitted acoustic signals are compared with the actual arrival times of the transmitted acoustic signals, and the results of the comparisons are stored. The stored results from two successive acoustic signal transmissions are then compared so as to either modify the first signal, if both acoustic signals arrived earlier or later than their respective expected arrival times, or to modify the second signal, if one acoustic signal arrived before, and the other after their respective expected arrival times.

A meter for measuring the velocity of a fluid by ascertaining propagation periods of acoustic wave packets transmitted therein, the meter including a pair of transducers for disposition in the fluid, a transmitter for transmitting a packet between the transducers in an upstream or downstream direction designated by an up/down signal at each time designated by a transmit signal and a receiver for developing a received signal marking the time of receipt by a transducer of each packet, the times being marked so as to avoid amplitude and half-cycle ambiguity errors. The meter also includes a phase detector for comparing the received times with those marked by a reference signal to develop early and late pulses, a decoder and a pair of integrators for developing from the pulses a pair of integrated signals representing changes in the upstream and downstream propagation periods, another integrator for combining the integrated signals to develop a signal representing the acoustic velocity of the fluid and an amplifier for combining the integrated signals to develop a signal representing the velocity of the fluid. Further, the meter includes a ramp generator for developing the up/down signal, a ramp signal and the transmit signal from the acoustic velocity signal and the combination of a multiplexer, a multiplier and a comparator for developing the reference signal, the multiplier for developing a signal inversely proportional to the acoustic velocity signal and multiplying it by a signal developed by multiplexing the integrated signals.

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Peacehaven, United Kingdom

Rodney C Johnson