Abstract: The new injection system provides rapid, high pressure, high density, and transient batch injection of cryogenic liquids. The system stores and maintains the temperature of liquids in vacuum jacketed tanks, increases pressures using pumps, and stores the high pressure fluid in accumulators. The accumulator periodically injects the fluids at high pressure in measured mass batches into a combustion chamber. The system injects enough liquid or gas in 0.5 to 3.0 seconds to provide 500 to 6500 psi in a closed chamber.

Abstract: A gas operated part forming die apparatus has compact high tonnage presses which are operated by high pressure gas generated within chambers and controlled to operate high pressure pistons and dies for compressing particulate material into dense formed parts. Combustion chambers are filled with pressurized mixtures of combustible gases and diluents. Elongated chambers have insulating walls and spaced electrodes. Some contain liquid or particulate ablatable materials or ablatable liners. Others extend fuzes between the electrodes and are filled with pressurized gases. Gas is removed from the particulate material. Die cavities may be precompressed during filing of chambers with pressurized gas. Igniting the combustible gases or creating arcs between the electrodes produces rapidly expanding high pressure resultant gases for driving pistons and movable dies and rapidly compressing die cavities. Pressures in the chambers are contained, or pistons are restrained until releasing and driving the pistons.

Abstract: A device for rapidly moving mechanically actuated devices, such as switches and valves with the capability of sub-millisecond response times being achievable with moving masses exceeding one kilogram. Response times approaching that of explosively actuated devices are obtained while retaining the repetitive cycling capability of non-explosively operated devices. Electrical energy stored in a capacitor pulses through electrodes and closed and open ends of a capillary tube to rapidly heat a gas and raise its pressure to a thousand atmospheres or more. The high pressure gas acts on a piston, accelerating it for a short distance before the pressure is vented around the piston to quickly reduce the drive force. The moving piston is brought to a stop by a hydraulic damping device. A reset device resets the piston, the capillary is refilled with working gas, and the capacitor is charged fro the next operation.

Abstract: A high voltage switch contact structure capable of interrupting high voltage, high current AC and DC circuits. The contact structure confines the arc created when contacts open to the thin area between two insulating surfaces in intimate contact. This forces the arc into the shape of a thin sheet which loses heat energy far more rapidly than an arc column having a circular cross-section. These high heat losses require a dramatic increase in the voltage required to maintain the arc, thus extinguishing it when the required voltage exceeds the available voltage. The arc extinguishing process with this invention is not dependent on the occurrence of a current zero crossing and, consequently, is capable of rapidly interrupting both AC and DC circuits. The contact structure achieves its high performance without the use of sulfur hexafluoride.

Abstract: A gas operated part forming die apparatus has compact high tonnage presses which are operated by high pressure gas generated within chambers and controlled to operate high pressure pistons and dies for compressing particulate material into dense formed parts. Combustion chambers are filled with pressurized mixtures of combustible gases and diluents. Elongated chambers have insulating walls and spaced electrodes. Some contain liquid or particulate ablatable materials or ablatable liners. Others extend fuzes between the electrodes and are filled with pressurized gases. Gas is removed from the particulate material. Die cavities may be precompressed during filing of chambers with pressurized gas. Igniting the combustible gases or creating arcs between the electrodes produces rapidly expanding high pressure resultant gases for driving pistons and movable dies and rapidly compressing die cavities. Pressures in the chambers are contained, or pistons are restrained until releasing and driving the pistons.

Abstract: A high voltage pulse generator provides a short, fast rise, high voltage pulse from a very low impedance suitable for initiating high energy electrical discharges in liquids and high pressure gases. Its low impedance allows extremely high currents from external energy storage capacitors to be conducted through the invention once the invention has initiated an arc. Its fast rise time is suitable for initiating multiple arcs or even sheet surface discharges in high pressure gasses under suitable conditions.

Abstract: A pulsed electrothermal powder spray apparatus and method increases coating particle velocities to the 2,000-4000 m/sec range. The apparatus includes a containment tube, which may be a reverse shock tube, having a capillary chamber section and a short barrel section. The tube is initially filled with an inert gas and powder is deposited in the barrel just downstream from the barrel's connection to the confined capillary discharge chamber. On receipt of a trigger signal, the muzzle shutter of the barrel section quickly opens, causing the inert gas to flow towards the open end of the barrel. A rarefaction wave propagates back up the barrel, towards the capillary chamber. Once the rarefaction wave reaches an electrode positioned at the front end of the capillary chamber, an arc discharge is triggered in the capillary, resulting in a quick rise in capillary temperature and pressure.

Abstract: Wire arc spraying using repetitively pulsed, high temperature gas jets, usually referred to as plasma jets, and generated by capillary discharges, substantially increases the velocity of atomized and entrained molten droplets. The quality of coatings produced is improved by increasing the velocity with which coating particles impact the coated surface. The effectiveness of wire-arc spraying is improved by replacing the usual atomizing air stream with a rapidly pulsed high velocity plasma jet. Pulsed power provides higher coating particle velocities leading to improved coatings. 50 micron aluminum droplets with velocities of 1500 m/s are produced. Pulsed plasma jet spraying provides the means to coat the insides of pipes, tubes, and engine block cylinders with very high velocity droplet impact.

Abstract: Paint is removed from bridges and structures by directing pulsed plasma jets at coatings on surfaces. The repetitively pulsed plasma jets ablate the coatings, and the resulting products are removed by reduced pressure in an enclosure. Plasma jets in an array are moved along a surface, with the jets overlapping. Power is controlled to remove the topcoats and one or more layers of topcoat without damaging an underlying primer coat, or to remove a primer coat to the bare surface. Jets in the array overlap to completely remove the coating. The pulsed plasma jets impact the surfaces directly in front of the plasma jets, and the gases flow outward, carrying ablated materials away from the surfaces. The enclosures have openings near the coated surface for allowing the inflow of ambient air into the reduced pressure enclosure to prevent escape of ablated products from the enclosure. The use of inert gas working fluid reduces formation of undesirable byproducts.

Abstract: Repetitively pulsed plasma jets generated by a capillary arc discharge at high stagnation pressure (>15,000 psi) and high temperature (>10,000 K) are utilized to produce 0.1-10 .mu.m sized metal powders and decrease cost of production. The plasma jets impact and atomize melt materials to form the fine powders. The melt can originate from a conventional melt stream or from a pulsed arc between two electrodes. Gas streams used in conventional gas atomization are replaced with much higher momentum flux plasma jets. Delivering strong incident shocks aids in primary disintegration of the molten material. A series of short duration, high pressure plasma pulses fragment the molten material. The pulses introduce sharp velocity gradients in the molten material which disintegrates into fine particles. The plasma pulses have peak pressures of approximately one kilobar. The high pressures improve the efficiency of disintegration. High gas flow velocities and pressures are achieved without reduction in gas density.