Abstract: For monitoring burner operation, such as in a refinery, boiler or the like, an acoustic sampler such as a piezo-electric microphone is located in a position to record an acoustic sample of the burner operation. The acoustic sample can be processed to determine whether the burner is operating normally or has suffered a flame out condition. Remedial actions can be undertaken to control the fuel supply to the burner if a flame out condition has been detected.

Abstract: Apparatus and methods are disclosed for determining internal engine characteristics using acoustic-vibration data. Exemplary such data are passive acoustic pyrometer data. Acoustic-vibrational frequencies emanating from a running engine are detected and compared to frequencies having known relationships to particular operating characteristics of the engine. In an example, the dominant frequency or other prominent frequency emanating from an internal-combustion chamber of a turbine engine is detected and used to determine the fuel-to-air ratio in the chamber. The determined data are used for performing adjustments or optimizations of engine performance, such as adjusting the fuel-to-air ratio as required or desired. In a similar manner, operating characteristics of other engines or engine-like environments, including furnaces and boilers, can be determined.

Abstract: Apparatus and methods are disclosed for determining internal engine characteristics using acoustic-vibration data. Exemplary such data are passive acoustic pyrometer data. Acoustic-vibrational frequencies emanating from a running engine are detected and compared to frequencies having known relationships to particular operating characteristics of the engine. In an example, the dominant frequency or other prominent frequency emanating from an internal-combustion chamber of a turbine engine is detected and used to determine the fuel-to-air ratio in the chamber. The determined data are used for performing adjustments or optimizations of engine performance, such as adjusting the fuel-to-air ratio as required or desired. In a similar manner, operating characteristics of other engines or engine-like environments, including furnaces and boilers, can be determined.

Abstract: The transit time of acoustic waves between a generator and a receiver positioned across a fluid chamber is determined by generating acoustic waves using a self-purging pneumatic sound generator, a transducer adjacent the outlet of the sound generator, and a receiving transducer positioned away from the sound generator outlet so that the acoustic waves received by the receiving transducer pass through a portion of the fluid. The electrical signals generated by the transmitting transducer and the receiving transducer are processed to obtain the impulse response of these electrical signals, and the point of maximum value is determined. This point of maximum value corresponds to the arrival time of the acoustic waves at the receiving location. The transit time determination may be used to calculate the fluid temperature or other parameters.

Abstract: The average volumetric velocity U.sub.m of a fluid flowing within a large industrial flue stack is determined by a combination of measurement and calculation techniques. The temperature, velocity head and static pressure of the stack fluid are measured at two points within the bounded path of the flue stack. The flight time of a random acoustic noise wave is measured in both the upstream and downstream directions. The path average velocity U.sub.p is determined from the measured values of the upstream and downstream flight times. The fluid velocity is determined using the measured values of the flight times, the fluid temperature, velocity head and static fluid pressure. The determined values of the path average velocity U.sub.p and the fluid velocities are used to determine the average volumetric velocity U.sub.m. A curve fitting algorithm is employed to determine an approximation of the actual fluid flow distribution across the bounded path, and this approximation is used to calculate U.sub.m.

Abstract: The transit time of acoustic waves between a generator and a receiver positioned across a fluid chamber is determined by generating acoustic waves using a self-purging pneumatic sound generator, a transducer adjacent the outlet of the sound generator, and a receiving transducer positioned away from the sound generator outlet so that the acoustic waves received by the receiving transducer pass through a portion of the fluid. The electrical signals generated by the transmitting transducer and the receiving transducer are processed to obtain the impulse response of these electrical signals, and the point of maximum value is determined. This point of maximum value corresponds to the arrival time of the acoustic waves at the receiving location. The transit time determination may be used to calculate the fluid temperature or other parameters.

Abstract: An apparatus and method for measuring high temperatures in a boiler transmits pulses of acoustic waves, from one side wall of the boiler to an opposite side wall thereof. Acoustic noise within the boiler, as well as the transmitted pulses of acoustic waves are received at the opposite side of the boiler. The received signal is digitized and compared to a digitized sample of the pulses during a time period which is more than the maximum transit time for the pulses between the side walls. A point of maximum correlation between the sample and the signal is taken as the arrival time for the pulse and is used to calculate the transit time of the pulse across the boiler. This transit time is used in turn to calculate the velocity of the pulses. The temperature can then be calculated as a function of the velocity, the molecular weight of the medium and the specific heat ratio of the medium. Each pulse has a modulated frequency between 500 and 3,000 Hz.