Showing papers on "Chamber pressure published in 1972"

Low pressure localized hyperbaric oxygen chamber

Abstract: A portable chamber is provided which permits the localized treatment, with low pressure oxygen, of non-healing ulcerations or lacerations of the body particularly the leg. In the case of a leg chamber, a sealing unit is adapted to be sealed to the patient''s leg above the ulceration. A transparent sleeve is adapted to detachably connect with the sealing unit and a sole plate which combines to effectively enclose the affected part of the leg within the chamber about the ulceration. An oxygen inlet connection is provided into the chamber with a manometer being employed to permit monitoring of chamber pressure and a pressure release valve being employed to permit adjustment of chamber pressure. A support may also be provided on the chamber exterior for purposes of preventing undesirable tilting or rolling of the chamber when sealed to the patient''s leg.

Chamber pressure control using free vortex flow

Abstract: Inlet means supplies a continuous flow of gas with a swirl velocity and at a chosen static pressure to a chamber to establish a free vortex flow therein. Surfaces define an annular path within the chamber that maintains the free vortex flow and guides it toward chamber outlet means. That portion of the chamber not including the annular path becomes pressurized to the supply static pressure of the gas, while the static pressure of the gas within the path changes with its distance from the vortex axis. By properly spacing and locating the inlet means from the outlet means and by properly sizing the annular path, the discharge static pressure of the gas can be controlled.

Boron Combustion Characteristics in Ducted Rockets

Abstract: A test program was performed with the objective of experimentally investigating the boron reaction characteristics in a ducted rocket by systematically varying the primary chamber conditions. In order to vary the primary chamber conditions a test device was used which burned boron powder and gaseous propellants (hydrogen or carbon monoxide, oxygen and nitrogen) in the primary motor. The reaction characteristics in the secondary chamber were observed by color photography through quartz windows of the secondary chamber. In the tests the following parameters were varied: (1) primary chamber temperature, (2) mixture ratio of the gaseous fuel in the primary chamber from below stoichiometric to above stoichiometric at different primary chamber temperature levels in order to vary the afterburning capability of the gaseous exhaust in the secondary chamber, and (3) secondary chamber pressure. At primary motor conditions which approximated propellants with high boron and low oxidizer/fuel content the boron...

Leak detector for sealed containers

Abstract: A leak detector for testing sealed containers formed of semirigid or flexible material. The container to be tested is placed in a chamber which is thereafter pressurized at a pressure distinctly different from the internal container pressure, whereby the container is caused to physically distort. A container dimension is first sensed before the chamber is pressurized to produce a first signal representing the dimension resulting from the difference between internal pressure and atmospheric pressure, this first signal being held. When the container is under pressure in the chamber and a predetermined time interval has elapsed, the container dimension is again sensed to produce a second signal representing the dimension as a result of the difference between internal pressure and chamber pressure. The held first signal and the second signal are compared and if the disparity therebetween indicates a significant change in dimension, the container is accepted, whereas if there is little disparity between signals, the container is rejected.

A conical arc driver for high-energy test facilities.

Abstract: Review of some exploratory test results for an electrical discharge driver with a conical-shaped arc chamber. The characteristics of the discharge cycle in the conical chamber and the shock tube performance are described, and the obtained results are compared with those reported by Menard (1971).

Calcium hydride gas generator

Abstract: A differential area gas operated hydraulic pump used in a bootstrap mode to pump water into a reaction chamber. Water is pumped into the reaction chamber until the level reaches a quantity of calcium hydride (Cah2) and reacts to produce just enough gas to exceed the operating pressure, whereupon the pump will stall. No further hydrolysis takes place until the chamber pressure is relieved at which time the pump again operates to raise the water level into contact with unreacted CaH2.

Fuel control means for a model engine

Abstract: Fuel control means for a model engine in which intake air is pre-compressed in a crank chamber of the engine, said fuel control means comprising a pressure responsive fuel control valve provided between a fuel tank and fuel injection nozzle means of the engine, the pressure in the crank chamber being introduced into the valve so as to control its opening in accordance with the crank chamber pressure. The crank chamber pressure is also introduced into the fuel tank so that the fuel in the tank is forced under pressure through the pressure responsive fuel control valve into the engine.

Air cushion apparatus

Abstract: Air pressure is conserved in an air cushion load conveying apparatus by valve elements disposed within the air pressure chamber in operative association with an array of relatively small holes which provide the pressurized air cushion between the wall of the chamber and an adjacent surface. The valve elements are constructed and arranged to rapidly respond to the pressure differential across the holes. They quickly open and transmit chamber pressure to the pressurized air cushion when an object is disposed close to the hole and rapidly close and preserve pressure when there is no object and concomitant air cushion disposed adjacent the hole. The valve elements are flapper valves made of a single large perforated flexible sheet or a number of smaller sheets which substantially obstruct the holes in the presence of a high differential pressure. The flapper valves inherently leak, which makes them sensitively respond to changes in pressure. The leakage is, however, not enough to cause an undue loss of air through closed holes. Bleed holes may be provided, if necessary, to accelerate movement under special conditions. The perforated chamber wall may be rigid for operating against regular smooth surfaces or it may be flexible for operating against irregular or interrupted surfaces. A flexible walled chamber may be used under a rigid pallet for transporting a load over irregular surfaces. The upper surface of the rigid pallet may also be perforated and valved to facilitate sliding loads on and off, and the pressurized air may be alternately supplied to the upper and lower portions to facilitate loading, unloading and transport.

Dustless sand blaster

Abstract: Sand or grit blasting equipment with a work-engaging chamber having a nozzle inlet. The chamber is positioned and moved parallel to a work surface by multiple spring-biased caster supports and is connected to a suction device, which may include a venturi to aid in maintaining reduced chamber pressure. A flexible, slit skirt extends about the work-engaging open end of the chamber to prevent escape of grit particles while allowing air streams to pass into the chamber. An open-work frame within the skirt limits inward deflection of the skirt.

Magnetic Pumping Effect on Dielectric Recovery of Blown SF6 ARCS

Abstract: Experimental measurements of the dielectric recovery rate of blown SF6 arc channels in a nozzle, following the interruption of 400 ?sec duration square current pulses of amplitudes between 20 A and 1000 A, have been made; the electrode spacing was 1 cm, and the upstream arc chamber pressure was either 35 psia or 60 psia.

Machine for continuous manufacturing of chip boards

Abstract: Machine for continuous manufacturing of chip boards, consisting of a strewing station for strewing chips to form a mat on a moving surface and a continuous action press for pressing the chip mat in the press gap between two moving surfaces, at least one of which consists of an endless belt, most appropriately a steel band, which is loaded by the aid of a pressure chamber to be urged in direction against the chip mat. The chip strewing station has been formed to constitute a chamber provided with a closable feed opening, which chamber directly communicates with the press gap provided with marginal seals and into which chamber pressure fluid can be introduced under a pressure which at the most equals the pressure prevailing in the pressure chamber.

Apparatus for determination of the magnitude of total specific energy absorbed by a sample of pulp stock

Abstract: 1. An apparatus for the determination of the magnitude of refining energy absorbed by a sample of pulp stock, said apparatus comprising: (A) stock sample chamber means separated from a stock reservoir by a perforated partition means adapted to pass the water vehicle of said stock but substantially obstruct passage of the stock fiber; (B) chamber pressure control means for regulation of pressure within said chamber relative to the pressures of said stock reservoir to selectively admit and expel said water vehicle; (C) at least two liquid level sensing means positionally separated within said chamber to delineate a prescribed volume therebetween;

Hot-gas-side heat transfer with and without film cooling on a simulated nuclear rocket thrust chamber using H2-O2

Abstract: Heat-transfer coefficients were obtained on a thrust chamber which simulated the geometry of the NERVA nuclear rocket. The tests were performed with and without peripheral film cooling over a chamber pressure range of 1.05 million to 5.84 million newtons per square meter (153 to 847 psia). With no film cooling, the overall axial variation in the value of the correlation coefficient C of the equation (Stanton)* (Prandtl)* to the 0.7ths power = C(Reynolds)* to the -0.2ths power, where * indicates the reference enthalpy condition, was reduced 66 percent when the local diameter in the Reynolds number was replaced by the axial distance from the injector face. The average peak values of C were reduced 25 percent with 2 and 3.75 percent cooling and 50 percent with 7.5 percent cooling.

Piston manometer as an absolute standard for vacuum gage calibration in the range 10 to 700 microtorr

Abstract: Total pressure in a calibration chamber is determined by measuring the force on a disk suspended in an orifice in the baseplate of the chamber. The disk forms a narrow annular gap with the orifice. A continuous flow of calibration gas passes through the chamber and annulus to a downstream pumping system. The ratio of pressures on the two faces of the disk exceeds 100:1, so that chamber pressure is substantially equal to the product of disk area and net force on the disk. This force is measured with an electrodynamometer that can be calibrated in situ with dead weights. Probable error in pressure measurement is plus or minus (0.5 microtorr + 0.6 percent).

Velocity and pressure effects on projectiles due to variation of ignition parameters

Abstract: : The effect of varying the point of ignition of the powder charge within a cartridge case was investigated with respect to both pressure and velocity. By installing a small tube in the base of the cartridge case it was possible to transfer the primer flash to the forward part of the case. Ignition of the powder charge at the top instead of the base gave lower chamber pressures by as much as 6,300 psi and increased muzzle velocity by 35 ft/s. When additional powder was added to obtain the same chamber pressure as a conventionally primed cartridge, muzzle velocities increased by 50 ft/s. When the pressure was brought up past the original level, but kept within normally accepted limits for the 7.62mm NATO round, velocities increased by 100 ft/s over the original load.

Hydrogen film/conductive cooling

Abstract: Small scale nozzle tests using heated nitrogen were run to obtain effectiveness and wall heat transfer data with hydrogen film cooling. Effectiveness data are compared with an entrainment model developed from planar, unaccelerated flow data. Results indicate significant effects due to flow turning and acceleration. With injection velocity effects accounted for explicitly, heat transfer correlation coefficients were found to be the same with and without film cooling when properties are evaluated at an appropriate reference temperature for the local gas composition defined by the coolant effectiveness. A design study for an O2/H2 application with 300 psia (207 N/sq cm) chamber pressure and 1500 lbs (6670 N) thrust indicates an adiabatic wall design requires 4 to 5 percent of the total flow as hydrogen film cooling. Internal regenerative cooling designs were found to offer no reduction in coolant requirements.

Characteristics of a vortex-stabilized plasma generator at reduced pressure

Abstract: The operation of an argon plasma generator at discharge chamber pressures in the region (3–100)·103 N/m2 has been experimentally investigated. Current-voltage characteristics in dimensional complexes have been obtained for stable operating regimes.

Effects of high combustion chamber pressure on rocket noise environment

Abstract: The acoustical environment for a high combustion chamber pressure engine was examined in detail, using both conventional and advanced theoretical analysis. The influence of elevated chamber pressure on the rocket noise environment was established, based on increase in exit velocity and flame temperature, and changes in basic engine dimensions. Compared to large rocket engines, the overall sound power level is found to be 1.5 dB higher, if the thrust is the same. The peak Strouhal number shifted about one octave lower to a value near 0.01. Data on apparent sound source location and directivity patterns are also presented.

Testing bond strength of semiconductor device assemblies

Abstract: A test method and apparatus for stressing beams leaded semiconductor device structures bonded to substrates is disclosed. A diffuser in close proximity to the chip surface causes a lower pressure on top of the chip than on the bottom because of gas flow out of the diffuser from the enclosing pressurized chamber. This creates a net force on the chip tending to lift it from the substrate. Varying the space between the chip and diffuser surfaces allows stepless control of the stress level applied to the chip, analogous to centrifuging. The force applied to the chip is typically increased to a predetermined value which is defined, using an established calibration technique, by the chamber pressure and the gas flow rate. However, forces great enough to remove the chip from the substrate may be generated if desired. This test method is also suitable for stressing a plurality of chips simultaneously.