Compact x-cross transducer array for a transit time flowmeter, particularly for use during in-vivo blood flow measurement

Multiple, typically four, acoustic transducers of a time delay acoustic flowmeter are arrayed in a X-cross, crisscross, folded geometry so as to establish a lengthy multiple-leg, typically a two-leg, acoustic path within a compact volume. An ultrasonic signal is transmitted from a transducer A to a transducer B, then electrically amplified and applied to a transducer C which retransmits the ultrasonic signal to a transducer D. The compact transducer configuration is particularly suitable for use during in-vivo blood flow measurement. The acoustic signal is maintained in amplitude from one leg to the next by amplification as an electrical signal.