Abstract: A separate-loading firearm, which may be configured as a muzzle-loading pepperbox pistol, uses a battery-powered electric resistance heating element to ignite a propellant. A relatively long current pulse, which may be of controllable duration, is used to ignite the propellant and a much shorter pulse may be used to test the integrity of the heater. Detection of the firearm's recoil may be used to terminate the relatively long firing pulse, which can increase the service life of the heating element and reduce the current drain from the battery.

Abstract: A separate-loading firearm uses a battery-powered electric resistance heating element to ignite a propellant charge. Both ignition reliability and ballistic reproducibility are enhanced when a first portion of the propellant charge is consistently and firmly packed into a cavity formed in a rear surface of a bullet. This first portion may be sealed in the cavity by a membrane. A second portion of the propellant charge is packed within a firing chamber so that it abuts both the heating element and the first portion of the propellant charge.

Abstract: A separate-loading firearm uses a battery-powered electric resistance heating element to ignite a propellant charge. Both ignition reliability and ballistic reproducibility are enhanced when a first portion of the propellant charge is consistently and firmly packed into a cavity formed in a rear surface of a bullet. This first portion may be sealed in the cavity by a membrane. A second portion of the propellant charge is packed within a firing chamber so that it abuts both the heating element and the first portion of the propellant charge.

Abstract: A magnetic flowmeter has multiple pairs of electrodes spaced apart along respective lines perpendicular to both a flow direction and a magnetic field. Respective flow-induced differential voltages from each pairing of electrodes are simultaneously summed to yield a measure of a flow rate. The summing arrangement increases the output signal proportionately to the number of electrode pairs, but increases the associated composite noise output proportionately to the square root of the number of those pairs.

Abstract: A transit time flow sensor is configured as an insertable probe carrying transducers spaced apart along an acoustic path that may be segmented. The transducers are attached to non-wetted surfaces of respective tabs extending outwardly from the probe and functioning as acoustic windows. The tabs are selectively skewed with respect to the probe's flow axis so that acoustic signals from one transducer are detected by another. Directly communicating transducers may be on the same or opposite sides of the probe's flow axis.

Abstract: A transit time flow sensor is configured as an insertable probe carrying transducers spaced apart along an acoustic path that may be segmented. The transducers are attached to non-wetted surfaces of respective tabs extending outwardly from the probe and functioning as acoustic windows. The tabs are selectively skewed with respect to the probe's flow axis so that acoustic signals from one transducer are detected by another. Directly communicating transducers may be on the same or opposite sides of the probe's flow axis.

Abstract: A transit time flow sensor is configured as an insertable probe carrying a pair of transducers spaced apart along an acoustic path. The transducers are attached to respective tabs extending outwardly from the ends of a tubular member and skewed with respect to an axis of the tube so that acoustic signals from one of the transducers are reflected from an interior portion of the tube and subsequently detected by the other transducer.

Abstract: A transit time flow sensor is configured as an insertable probe carrying a pair of transducers spaced apart along an acoustic path. The transducers are attached to respective tabs extending outwardly from the ends of a tubular member and skewed with respect to an axis of the tube so that acoustic signals from one of the transducers are reflected from an interior portion of the tube and subsequently detected by the other transducer.

Abstract: An ultrasonic flow meter comprises a cavity disposed in the wall of a flow tube. This cavity is preferably elongated along a direction perpendicular to a flow axis and has a flat interior surface portion proximal an interior surface of a wall of the flow tube. A piezoelectric transducer has a surface bonded to the flat interior surface portion of the cavity so as to transmit and receive acoustic signals through a thin window in the wall of the flow tube. An encapsulant, which may be combined with other elements, such as a mechanical strengthening piece, bonds the second side of the piezoelectric wafer to a second surface of the cavity. In a particular preferred embodiment, the cavity may be a dovetailed groove cut into a wall of the flow tube.

Abstract: An ultrasonic flow meter comprises a cavity disposed in the wall of a flow tube. This cavity is preferably elongated along a direction perpendicular to a flow axis and has a flat interior surface portion proximal an interior surface of a wall of the flow tube. A piezoelectric transducer has a surface bonded to the flat interior surface portion of the cavity so as to transmit and receive acoustic signals through a thin window in the wall of the flow tube. An encapsulant, which may be combined with other elements, such as a mechanical strengthening piece, bonds the second side of the piezoelectric wafer to a second surface of the cavity. In a particular preferred embodiment, the cavity may be a dovetailed groove cut into a wall of the flow tube.

Abstract: A DC-DC power converter used in an electromagnetic flowmeter supplies a constant current from a capacitive output to an excitation coil during a measurement portion of the operating cycle. During a relatively longer charging portion of the operating cycle the capacitive output is charged from an unregulated supply. When the unregulated supply voltage of the of the DC-DC converter is less than the regulated output voltage repeated high voltage pulses are generated by the excitation coil to charge the output capacitor.

Abstract: Acoustic reflectors in a pipe can aid in defining an ultrasonic beam for a transit time flow measurement. Flow impedance associated with such reflectors can be minimized by using reflectors comprising an array of parallel reflective facets elongated transverse to an axis of the pipe and skewed with respect to the axis of the pipe. These facets may be formed in the wall of the pipe—e.g., by cutting grooves. Alternately, facet arrays may be formed in a separate low-profile body that is then attached to an inner wall of the pipe.

Abstract: An edge of a piezoelectric disk transducer is biased into an external wall of a flow passage by a spring. The disk is then driven at a radial mode resonant frequency to project acoustic energy into fluid flowing in the passage. This arrangement is compatible with several types of fluid flow sensors such as transit time, Doppler, and vortex shedding flow meters.

Abstract: A calibrator for calibrating a compatible heat transfer meter comprises a temperature controlled reference thermowell and a reference temperature sensor. The reference thermowell is similar in dimensions to thermowells usable for measuring inlet and outlet temperatures of a heat exchanger so that the reference temperature sensor is selectively insertable into any of the thermowells. The calibrator also comprises temperature measurement circuitry operable to generate a temperature reading from an output of the reference temperature sensor; and control circuitry operable to control the temperature of the reference thermowell.

Abstract: A flow measurement in a conduit is combined with a thermal flow measurement made in a bypass channel to provide an increased range of flows over which an accurate measurement can be made. The thermal flow sensor in this combination is responsive only to a modulated component of the flow and thus provides a means of calibrating the zero of the composite instrument.

Abstract: A vortex-shedding flowmeter uses two ultrasonic transducers to generate an acoustic beam at a selected carrier frequency. Vortices generate fluid oscillations that are detected when they pass through the beam and induce phase changes representative of fluid flow rate. In an improved vortex-shedding flowmeter each of the transducers is connected to a separate transformer and the outputs of the two transformers are interconnected to yield the phase change.

Abstract: A thermal flow sensor is responsive only to a modulated component of the flow. At zero flow the modulated component disappears, except for an artifact caused by motion of the modulator. This artifact is minimized by reducing the extent of modulator motion and by sampling the modulated signal at a quiescent part of the modulator's operating cycle. This results in a thermal flow sensor with a very stable zero.

Abstract: Zero and calibration drift errors in a magnetic flow meter can be detected and automatically corrected. A zero error can be detected by measuring an amplifier output when the meter's electromagnet is inactive. Automatic calibration of the span can be done by adding a signal to a measured electrode voltage at an amplifier input, subtracting the expected amplified value of that signal at the output and adjusting the amplifier gain responsive to the difference in signal magnitude.

Abstract: Vortex-shedding flow meters are operated at a sampling frequency high enough to detect each vortex multiple times. Using a fixed sampling frequency high enough for a maximum rate of vortex generation oversamples the vortices generated at low flow rates. Adjusting the sampling rate to accord with the flow rate being measured significantly reduces electric power consumption.

Abstract: A vortex flowmeter has a flow conditioning structure entirely inside a flow tube and an externally mounted pair of ultrasonic transducers for detecting vortices generated by vortex shedding structures within the flow tube. The flow conditioning structure can be installed within a short flow tube section retaining the shedder and providing a flow passage having a desired shape. The use of external transducers, coupled with a selectable flow conditioning structure allows many calibration and maintenance tasks to be performed without having to shut down flow and access the passive components inside the tube.