Abstract: A portable computing device is used for acoustic testing of valve systems for valve leaks. Transducers are applied to appropriate locations in the valve system to obtain sound signals, which are fast Fourier transformed into valve signatures. Multiple signatures are displayed simultaneously and are compared automatically by the system to derive a recommended result and manually to make determinations of valve leaks by the differential signature method or the like. The signatures and the user's determinations are stored on a hard drive. Various panels are displayed to give the user step-by-step instructions for performing the test. The results can be reported to the client's office computers.

Abstract: A device for testing hydraulic actuators using acoustical transducers to se sound sources indicative of leaks or other defects in the actuator. A graph of acoustic signals versus piston location may be determined using one acoustic transducer and one position sensor. A correlation function may be obtained by cross-correlating the output from two spaced acoustic transducers.

Abstract: The invention relates to a leak detecting device for pipe systems having electronic channels for processing the acoustical signals from the source of the leak to determine the direction of propagation of the leak signal. Each channel includes a transducer, an amplifier unit, a variable delay unit for delaying the transmission of signals received from the amplifier unit, and a multiple-averager unit which respectively multiplies and then averages input signals from the variable delay unit of the same channel and, depending on the mode of operation, from the amplifier unit of either the same or the other channel. Operating in a first mode to determine the frequency and wavelength of the primary leak signal, the signals from the variable delay unit of one channel are combined with the signals from the amplifier unit of the same channel in the multiplier-averager unit.