Showing papers on "Chamber pressure published in 1979"

Design and evaluation of high performance rocket engine injectors for use with hydrocarbon fuels

Abstract: The feasibility of using a heavy hydrocarbon fuel as a rocket propellant is examined. A method of predicting performance of a heavy hydrocarbon in terms of vaporization effectiveness is described and compared to other fuels and to experimental test results. Experiments were done at a chamber pressure of 4137 KN/sq M (600 psia) with RP-1, JP-10, and liquefied natural gas as fuels, and liquid oxygen as the oxidizer. Combustion length effects were explored over a range of 21.6 cm (8 1/2 in) to 55.9 cm (22 in). Four injector types were tested, each over a range of mixture ratios. Further configuration modifications were obtained by reaming each injector several times to provide test data over a range of injector pressure drop.

Compressor modulation delay valve for variable capacity compressor

Abstract: A modulation delay valve for a variable capacity compressor operative to prevent the premature reduction of the pumping capacity of the compressor. A compressor suction chamber pressure sensing bellows, located in a pressure control cell, regulates a hydraulic control valve which in turn controls the flow of oil to a hydraulic cylinder operative to vary the displacement of the compressor. The delay valve functions, by sensing a compressor discharge reference pressure, to delay the operation of the hydraulic control valve by cutting-off communication of the suction pressure signal to the bellows cell allowing the compressor to maintain its maximum pumping rate. Upon the compressor discharge chamber pressure falling below the reference pressure the delay valve discharge cavity pressure correspondingly falls, allowing the delay valve to open communication between the bellows control cell and the compressor suction chamber to resume modulation of the compressor.

Pressure compensating shaft seal

Abstract: Relatively rotating face ring-type shaft seals especially useful for sealing the shaft bearings and lubricant chamber of mud motor driven downhole drill rigs, have a plurality of telescoped annular seal rings slidably mounted in an annular carrier element and riding over the radial face on a face ring to define a sealed intermediate chamber therebetween. This intermediate chamber may be filled with lubricant. Either the telescoped rings or the face rings rotate with the shaft. Biasing means, such as a plurality of springs, load end faces on the seal rings against the radial face of the face ring. Pressure transmission means, such as pistons, O-rings, or the like, mounted in either the carrier element or the face ring, are loaded by the ambient media pressure, such as drilling fluid, to maintain pressure in the intermediate chamber responsive to the pressure of the ambient media. When the areas of the pressure transmission means exposed to ambient pressure and to intermediate chamber pressure are equal, a zero or negligible pressure differential will be maintained across the outer telescoped seal ring to prevent the ambient media, which is frequently quite abrasive, from entering the outer sealing ring interface. The inner telescoped seal ring serves as an auxiliary back-up face ring seal for the protected bearing chamber. Since the abrasive media being sealed does not enter the interfaces of the rings, the end faces of the inner and outer sealing rings riding on the face ring can be reduced or narrowed to a minimum and coated with a hard facing material such as tungsten carbide.

Apparatus for biocidal sterilization using cyclic subatmospheric pressure conditioning

Abstract: Conditioning of goods for subsequent sterilization with a biocidal agent in a sealable chamber includes removal of air, and moistening and heating the goods to the desired temperature levels. Controlled evacuation of the chamber and coordinated admission of conditioning vapor into the chamber provides cyclic variations in chamber pressure between preselected subatmospheric pressures to subject goods in the chamber to a plurality of cyclic subatmospheric pressure pulses. The time required for the cyclic pressure variations is responsive to load characteristics, including heat and moisture absorption characteristics of the goods being conditioned, and is independent of prescribed times or direct measurement of load temperature. The subatmospheric pressure levels are selected based on the temperature-pressure relationship of the conditioning vapor so that chamber temperature during cyclic pulsing does not exceed the desired sterilization temperature.

External air release control in seismic air gun

Abstract: Disclosed is a seismic source device, known in the industry as an air gun, having shuttle and external sliding valve control for allowing a predetermined discharge of compressed air into water for purposes of seismic exploration. The shuttle is controlled by air pressure to move it upward, thereby permitting compressed air in the firing chamber to exhaust through exhaust ports. The external sliding valve had been held in a downward position by air pressure supplied from the firing chamber, compressing a spring. As the firing chamber pressure drops, the compressed spring expands, forcing the sliding valve to move upward, closing the exhaust ports. By preventing further discharge of air, secondary pulses are greatly reduced, with little or no loss in acoustic output, thereby enhancing the operation of the entire system. Further, by preventing all the air in the firing chamber from being discharged, the system becomes more efficient and more cost effective.

Pilot actuated diaphragm valve

Abstract: A diaphragm valve operated by a solenoid pilot for opening and closing the gasoline passage from a pumped inlet to the nozzle of a gasoline dispenser. A valve body forms an internal fluid passage for series installation with that of the dispenser. An annular seat surrounds the body passage at an intermediate location while an upstream facing diaphragm cooperates with the seat to open and close the passage to fluid flow. A spaced apart valve plate in combination with the diaphragm form a liquid tight chamber into which gasoline at the inlet can enter through restrictive one-way orifices. Fluid pressure in the chamber aided by a bias spring urges the diaphragm toward the set in opposition to pump pressure at the inlet. The pilot valve is spring biased toward a closed relation and is loop connected from the chamber to the outlet. Energizing the pilot effects a reduction in chamber pressure enabling relatively greater inlet forces against the diaphragm to move the diaphragm toward open position. The pilot valve also operates as a backflow restrictor from the dispenser hose and in response to an overpressure opens to permit backflow to the chamber. A relief valve located internally of the chamber operates in conjunction with pilot backflow operation to relieve chamber pressure buildup to the inlet.

Performance of a transpiration-regenerative cooled rocket thrust chamber

Abstract: The analysis, design, fabrication, and testing of a liquid rocket engine thrust chamber which is gas transpiration cooled in the high heat flux convergent portion of the chamber and water jacket cooled (simulated regenerative) in the barrel and divergent sections of the chamber are described. The engine burns LOX-hydrogen propellants at a chamber pressure of 600 psia. Various transpiration coolant flow rates were tested with resultant local hot gas wall temperatures in the 800 F to 1400 F range. The feasibility of transpiration cooling with hydrogen and helium, and the use of photo-etched copper platelets for heat transfer and coolant metering was successfully demonstrated.

Internal combustion engine for compound use

Abstract: An internal combustion piston engine operates without a blowdown phase and is compounded with a turbine (18) utilizing substantially steady inlet pressure. A compressor (1) delivers air compressed to at least that steady pressure to the inlet port (3) of a combustion chamber (13) whose exhaust port (16) is ducted to the turbine's inlet (17). Fuel is added to the compressed air in the chamber (13) and upon ignition of the charge, the piston (5) is driven in a power producing expansion stroke. On each upstroke of the combustion chamber piston (5), combustion products pass through the exhaust port (16) into the turbine inlet duct (17) while the compressed air simultaneously enters the chamber (13) through the inlet port (3). By late closure of the inlet and exhaust ports to restrict compression ratio and by regulation of the quantity of fuel burned per combustion period, the combined pressure rise in the chamber from compression and fuel combustion is limited to a value equal to or less than the subsequent chamber pressure decrease from the piston expansion stroke. Preferably, several cyclically phased combustion chambers provide substantially steady exhaust flow to the turbine.

Some effects of cyclic induced deformation in rocket thrust chambers

Abstract: A test program to investigate the deformation process observed in the hot gas wall of rocket thrust chambers was conducted using three different liner materials. Five thrust chambers were cycled to failure using hydrogen and oxygen as propellants at a chamber pressure of 4.14 MN/m square (600 psia). The deformation was observed nondestructively at midlife points and destructively after failure occurred. The cyclic life results are presented with an accompanying discussion about the types of failure encountered. Data indicating the deformation of the thrust chamber liner as cycles are accumulated are presented for each of the test thrust chambers.

Oil seal for marine propeller shaft - has high pressure shaft seal separated from water by low pressure seal

Abstract: The marine propeller shaft oil seal has two seals forming a separate oil chamber (11) between the water and the inside of the propeller shaft tunnel. The oil chamber is linked to the propeller shaft tunnel by a pressure control valve which operates in conjunction with the outside water pressure, and holds the chamber pressure lower than the water pressure. The lower pressure provides improved oil seal without straining the sealing lips. The tunnel pressure is higher than the water pressure and is supplied from a reservoir (30) above the waterline. The oil seal pressure is automatically adjusted w.r.t. water pressure by a membrane piston (19) on the control valve.

Design, fabrication and delivery of a high pressure LOX-methane injector

Abstract: An injector for 3000 psia chamber pressure using liquid oxygen and gaseous methane propellants is presented. The injector is intended to be evaluated during a series of pressure-fed test firings using a water-cooled calorimeter chamber and a milled-slot regenerative chamber. Combustion efficiency, combustion stability, ignition and injector face heat transfer assessments were made for candidate injector body and pattern design approaches. This evaluation resulted in baselining an oxidizer post type manifold with a 60 element platelet coaxial swirler injector pattern. An axial acoustic resonator cavity was created at the injector/chamber interface.

Die casting machine

Abstract: A hot chamber pressure casting machine of the type having a gooseneck for drawing molten metal from a reservoir and injecting it into at least one die set movably mounted on a back plate. In one aspect of the invention, a track is provided on the back plate along which closure means for the die is adjustable. In another aspect of the invention, the back plate is in or near a vertical plane and the gooseneck nozzle has a passage, a major part of which lies in or near a horizontal plane when the nozzle is engaged with the die, and the end portion of the passage is inclined upwardly from the major part to the end.

Ink jet printer drop speed measurement - by measuring time between pressure generator impulse and drop detection signal

Abstract: The method, device, and detectors are for monitoring the speed of drops in an ink spray printer and operate when the print head is at one end of its line movement. The head has compression chambers with an ink holder contg. ink or an interchangeable fluid used for monitoring purposes. Ink or the monitoring fluid drops are fed to the head nozzles by applying short duration pressure increases to the compression chambers. A detector enables the time of ejection of a drop from the head. The time between the impulse signal application to the chamber pressure increase generator and the signal from the detector is determined and compared with given measurement path limits. Correction signals are derived from the degree by which the measured time interval lies outside the comparator limits.

Double acting hydraulic jack control for drilling machine - has spool valve operating in three pressure stages, and non-return pilot valve controlling flow from piston rod chamber

Abstract: The double acting hydraulic cylinder control has pressure lines connected to each end of the cylinder, a third line extending from an hydraulic motor circuit to the pilot inlet of a spool valve. The latter has outlets coupled to the cylinder pressure lines, the system operating in three pressure stages. A non-return pilot valve, operated by the pressure line to the piston chamber, to position in a line from the rod chamber pressure line to exhaust or atmos. This pilot valve is closed when no pilot pressure exists.

Effects of back-pressure saturation techniques on results of R triaxial compression tests

Abstract: : Corps of Engineers (CE) soil laboratories achieve 100 percent saturation of R and R triaxial compression test specimens by the use of back pressure applied in small increments concurrently with increase in chamber pressure with adequate time between increments to permit equalization of pore-water pressure throughout the specimen. The objective of this procedure is to apply sufficient pressure on the pore water and pore air so that the air is dissolved in the pore water without significantly prestressing (overconsolidating) the specimen. The objectives of this investigation were to determine the effects of the magnitude of back pressure and the procedure by which it is applied on the stress deformation characteristics of soils. The objectives were achieved by comparing results of tests performed on compacted specimens of Vicksburg loess (clayey silt (ML)) and Vicksburg buckshot (plastic clay (CH)) in which the back-pressure saturation procedure was varied and results of tests performed on specimens of Vicksburg buckshot consolidated from a slurry in which the magnitude of the total back pressure was varied. The results indicate that variations in the technique of applying back pressure may significantly affect test results.