Abstract: Arrival of a pressure wave front is detected at a plurality of monitoring stations spaced along a protected section of a fluid-carrying pipeline. Arrival times obtained at the monitoring stations are qualified as to whether they correspond to a pressure transient event (critical event) which originated in the protected section. If so, the location, amplitude and time of occurrence of the critical event are determined. An uncertainty zone is derived at the extremes of the protected section having a length dependent on the precision of a time standard to which the monitoring stations are referenced and on the exactness of fluid velocity in the pipeline. An operator is so informed if the location of the critical event is determined to fall in the uncertainty zone. It is also possible to determine whether wave fronts correspond to an event occurring outside the protected section. Information from the resulting pass-through wave is used to update needed parameters useful for the critical event determinations.

Abstract: A time of arrival of a pressure wave front travelling through fluid in a pipeline due to an event which causes fluctuation of pressure in such fluid is determined. The characteristic related to the pressure of the fluid is measured at a given position along the pipeline. A rate of change of the fluid pressure is determined for each measured pressure value by calculating a straight line derived from a plurality of such pressure values. The slope of the current straight line is compared to a threshold derived from a plurality of slopes obtained for previous pressure values, and a signal is outputted when the slope exceeds the threshold. Such signal is indicative of the time of arrival of the pressure wave front. The time of arrival is utilized to obtain the magnitude of the event, the location on the pipeline at which the event occurred, and its time of occurrence.

Abstract: A self-calibrating temperature sensing probe having a temperature sensor positioned adjacent to a vial of a predetermined substance in an isothermal environment created by a housing and insulation. A heating element is positioned about the vial to effect vial heating. The substance is preselected for its melting point temperature, which is in excess of the ambient temperature of the environment surrounding the housing. During recalibration the substance is heated above its melting point and allowed to cool. During cooling the temperature of the substance is recorded and the liquid-to-solid phase change determined. Recalibration is affected using the phase change temperature of the substance as a calibration point.

Abstract: A probe has a housing which includes a moisture sensor for providing a non-linear moisture-related signal and a signal processor for linearizing the moisture-related signal and converting the signal to a digital output signal indicative of a moisture measurement. Temperature and pressure sensors are also included and provide a temperature-related signal and a pressure-related signal in the probe. The signal processor processes the moisture-related signal as a function of one or both of the temperature and pressure-related signals and provides another moisture-related output signal. The signal processor includes a serial data output for transmitting the digital moisture-related signal and digital temperature and pressure-related signals along a signal data transmission line.

Abstract: A digital valve assembly has a body provided with a plurality of planar sides and has an inlet passage running axially thereinto and opening past an axial projection and through a plurality of inlet branch passages in divergent array to inlet valve openings on the respective sides of the body. There is also an outlet passage substantially coaxial with the inlet passage and open at the other end of the body. In communication with the outlet passage over an axial projection therein is a plurality of outlet branch passages, each opening on a respective one of the body sides and converging therefrom toward the outlet passage. The outlet valve openings and inlet valve openings are close together or are paired, so that each pair is coverable by a respective one of a number of valves, each mounted on the body on one of the sides in a position to control flow through the openings therein.

Abstract: A burner for mixtures of air and gas has a generally closed burner body extending along an axis. There is an entrance portion at one end of the body open to the atmosphere and an exit portion at the other end of the body having a second opening to the atmosphere. The body is generally defined between a relatively flat top plate and a converging, relatively flat bottom plate and between curved side plates to establish a rectangular enclosure. The entrance portion decreases in transverse cross-sectional area away from the entrance opening to a high-velocity zone having a minimum transverse cross-sectional area from which the exit portion flares between the central zone and the exit opening with a substantially constant cross-sectional area. A gas tube extends along the axis through the entrance opening and into the entrance portion to a point somewhat short of the high-velocity zone.