Abstract: A spectrometric multigas analyzer is disclosed utilizing substantially isobaric temperature modulation of a gaseous sample in a highly reflective, random path, optical cavity or chamber. Multiple hot and cold ports on opposite sides of the chamber, and a gas recirculation circuit including a heating chamber, thermal regenerator, and cooling chamber, facilitate the alternate replacement of hot gas with cold gas and cold gas with hot gas in the optical chamber each cycle at a frequency of at least several Hertz, thereby producing, by gases of interest in the sample, a modulated spectral infrared emission and a modulated spectral radiant absorption of radiance from a radiant source shining into the optical chamber, which radiant source also provides heat for the heating chamber.

Abstract: A thermocompressor is disclosed as including a free piston which coasts upwardly and downwardly in a bypass region of a cylinder between cold and hot rebound chambers at cold and hot ends of the cylinder located at the top and bottom of the cylinder. A compressible fluid alternately flows downwardly and upwardly between the cold and hot cylinder ends via the cylinder bypass in response to the alternate upward and downward coasting of the piston. This alternate fluid flow, in conjunction with a thermal lag heating chamber, regenerator, and cooling chamber, causes an alternate heating and cooling of the fluid which produces a cyclical fluid pressure variation utilizable for driving a load. Although the regenerator, and generally the cooling chamber, are located in the bypass, the thermal lag heating chamber is located beyond the bypass and communicates separately with the lower or hot end of the cylinder for thermal lag driving of the piston during a hot rebound portion of the cycle.

Abstract: Presence of a substance in a gaseous medium is detected by introducing a controlled quantity of the gaseous medium into a variable volume chamber including a cylinder having a hemispherical end wall with optically polished internal surface, and adiabatically compressing the gas by means of a piston reciprocable with the cylinder. The face of the piston opposite the hemispherical end wall of the cylinder is also of hemispherical contour. Upon adiabatic compression of the gas the temperature thereof increases to produce spectral emissions from the gaseous constituents, modulated in accordance with the recurrent variation of volume of the chamber. A detector is provided to sense any emissions occurring within the chamber at the wavelength of the substance in question.

Abstract: A closed cylinder contains a thermally driven free piston oscillating between hot and cold ends of the cylinder which ends are respectively connected to a thermal lag heating chamber and a turbine/cooling chamber. A thermal regenerator is provided within a cylinder bypass which bypasses a portion of the cylinder between hot and cold rebound chambers which include, respectively, the hot and cold ends of the cylinder. The hot rebound chamber also includes the thermal lag heating chamber. The heating chamber has sufficient thermal lag properties for substantially heating gas therein as the piston is rebounding away from the hot end of the cylinder, thereby sustaining piston oscillation.

Abstract: Presence of a substance in a gaseous medium is detected by introducing a sample of the gaseous medium under consideration into a variable volume cavity formed by the walls of a cylinder and the operating face of a piston reciprocable in the cylinder, the adiabatically compressing the gas in the cavity by cyclic reciprocation of the piston to increase the temperature of the gas and thereby cause emission of radiant energy by constituents of the gas sample at their respective characteristic emission spectra. The emissions are modulated in accordance with the recurrent variation of volume of the cavity. The piston is gas-centered during operation to inhibit sliding contact between surfaces and thereby permit oilless and powderless operation which would otherwise present contaminants tending to interfere with detection of the substances of interest.

Abstract: A closed cylinder contains a thermally driven free piston oscillating between hot and cold ends of the cylinder which ends are respectively connected to a thermal lag heating chamber and a turbine/cooling chamber. A thermal regenerator is provided within a cylinder bypass which bypasses a portion of the cylinder between hot and cold rebound chambers which include, respectively, the hot and cold ends of the cylinder. The hot rebound chamber also includes the thermal lag heating chamber. The heating chamber has sufficient thermal lag properties for substantially heating gas therein as the piston is rebounding away from the hot end of the cylinder, thereby sustaining piston oscillation.

Abstract: A monitoring system for detecting changes in the fluidic impedance of the boundary regions or volume of an enclosure, including detecting entry into, as well as certain movements within, a substantially sealed enclosure by means of synchronous detection of a modulated pressure signal within the enclosure. The air pressure within the enclosure is modulated at a predetermined amplitude and at a frequency which is sufficiently low to substantially avoid reverberation and wave interference effects, and means tuned to that frequency produce electrical signals indicative of the amplitude and phase, whereby entry into or exit from the enclosure, opening of a chamber within the enclosure, or blockage or unblockage of passageways within the enclosure vary the amplitude and/or phase of the modulated pressure, thereby causing an electrical signal to vary sufficiently to actuate an alarm.

Abstract: A monitoring system for detecting changes in the fluidic impedance of the boundary regions or volume of an enclosure, including detecting entry into, as well as certain movements within, a substantially sealed enclosure by means of synchronous detection of a modulated pressure signal within the enclosure. The air pressure within the enclosure is modulated at a predetermined amplitude and at a frequency which is sufficiently low to substantially avoid reverberation and wave interference effects, and means tuned to that frequency produce electrical signals indicative of the amplitude and phase, whereby entry into or exit from the enclosure, opening of a chamber within the enclosure, or blockage or unblockage of passageways within the enclosure vary the amplitude and/or phase of the modulated pressure, thereby causing an electrical signal to vary sufficiently to actuate an alarm.

Abstract: A passageway forming a nozzle supplies a positive pressure impulse, derived from an oscillatory pressure source, to blades of a turbine mounted in a chamber. The passageway conducts fluid in a direction from the source toward blades of the turbine during a first portion of the oscillatory cycle while the pressure of the source exceeds the pressure of the fluid proximate the turbine. The fluid is directed by the nozzle in a concentrated stream toward the blades. During a second portion of the cycle while the source pressure is less than the fluid pressure proximate the turbine, fluid diffusely flows in the chamber away from proximate the turbine toward the source. The diffusely drawn fluid produces a negative pressure impulse on the turbine. The negative pressure impulse is substantially weaker than the positive impulse, whereby a net positive torque is exerted on the turbine to continuously drive the turbine in a positive rotational direction.

Abstract: A monitoring system for detecting changes in the fluidic impedance or volume of the boundary or bounded regions of an enclosure, including detecting entry into, as well as certain movements within, a substantially sealed enclosure by means of non-synchronous or synchronous detection of a modulated pressure induced within the enclosure. The air pressure within the enclosure is modulated at a predetermined amplitude and frequency, and means tuned that that frequency produce electrical signals indicative of the amplitude and possibly phase, whereby entry into the enclosure, blockage or unblockage of passageways within the enclosure, or movement of certain objects within the enclosure vary the amplitude and/or phase of the modulated pressure in one or more bounded regions of the enclosure, thereby causing the electrical signal or signals to vary sufficiently to actuate an alarm.

Abstract: A manually operated, manually-powered, hand held suction device for capturing insects, solder, or other small objects by creating and then discharging a stored vacuum. A suction pulse is produced by initially creating a vacuum in an internal storage chamber of the suction device by using a manually operated piston pump, and subsequently creating an instantaneous suction into the muzzle or nozzle of the device and thence into the storage chamber by opening a trigger actuated shutter valve which lies in the barrel between the chamber and the atmosphere. The pump may include two check valves whereby repeated operation of the pump strengthens the stored vacuum. The object is sucked into the valve and toward the chamber where it is stopped by a screen. The object can then be ejected back through the muzzle by reversing the check valves or the direction of motion of the piston, pressurizing the chamber by means of the piston pump, and again pulling the trigger.

Abstract: A substantially closed cylinder containing a compressible fluid, such as air, and a free piston for reciprocation within the cylinder, and a number of elongated passageways, each having an end opening into the cylinder and an opposite closed end. The passageways are heated along their lengths. The fin-shaped open end portions and the cylinder wall are cooled. Piston reciprocation is effected by the force of heated expanding gas moving from the closed ends of the passageways to drive the piston in one direction as the gas cools in the region between the piston end and the cooled open ends of the passageways. The piston compresses the gas at the opposite piston face, which gas in turn drives the piston back after the force of the compressed gas exceeds the force of the cooling gas to regularly repeat such cycle.