Showing papers on "Chamber pressure published in 1981"

Establishing and ascertaining desired air removal in steam sterilization

Abstract: Air removal is completed and ascertained, in steam sterilization systems which use steam flow through a sterilizing chamber to facilitate air removal, by methods which enable steam-table values for a dependent variable relationship of pressure and temperature, as exhibited by confined saturated steam, to be utilized under steam flow conditions. Apparatus for controlling and measuring chamber conditions are provided so that such established steam-table values for confined steam can be readily and reliably used to establish and ascertain complete air removal while steam is flowing through the chamber. In a representative embodiment, chamber pressure is held substantially constant while the remaining variable chamber temperature is measured. Venting of chamber atmosphere is continuous during such control of chamber pressure with chamber temperature being measured until a value is reached corresponding to the steam-table value at the level of the chamber pressure being held. With complete removal of the air ascertained, sterilizing exposure conditions can be established rapidly by substantially reducing venting of chamber atmosphere since any remaining portions of the cycle, whether establishing or maintaining sterilizing exposure conditions, need not be relied on for removal of air. Control apparatus, electromechanical and electronic processor, are provided for automatically completing air removal and ascertaining effective air removal.

Sterilizer with inflatable article holder

Abstract: Apparatus for holding medical and other devices while sterilant gas is passed over and through the device. The apparatus comprises an inflatable cuff which inflates by interior pressure as the pressure in the sterilizer chamber decreases, and relaxes as chamber pressure increases, thereby alternately holding the device and exposing its surfaces to the sterilant gas and desorbing gas.

Thermal regenerative injector

Abstract: A thermal regenerative injector 10 for a rocket engine that transfers heat from a fuel after turbine operation to the fuel prior to turbine operation, thereby providing a higher chamber pressure and lower fuel pump pressure. The injector 10 has a plurality of elements 44 having concentric channels 78, 80, and 82 separated by sleeves 66, 68, and 70, the fuels flowing therethrough, heat being transferred through a common middle sleeve 68, The cold fuel, after being so heated, is heated further in the typical fashion of routing it through the combustion zone and nozzle cooling jackets 16 and 20.

Effect of deformation on flame spreading and combustion in propellant cracks

Abstract: A comprehensive theoretical model was formulated to study the development of convective burning in a solid propellant crack which continually deforms due to burning and pressure loading The effect of interrelated structural deformation and combustion processes was included in the theoretical model The set of coupled, nonlinear, governing partial-differential equations was solved numerically Several regions of partial crack closures were observed experimentally in narrow cracks (gap width -450 /on) Predicted results indicate that the partial closures may generate substantial local pressure peaks along the crack, implying a strong coupling between chamber pressurization, crack combustion, and propellant deformation, especially when cracks are narrow and chamber pressurization rates are high Predicted results for ignition-front propagation and pressure distribution are in good agreement with experimental data Both theoretical and experimental results indicate that the maximum pressure in the crack cavity is generally higher than that in the chamber Under the conditions studied, it was found that the initial flame-spreading process is not affected substantially by propellant deformation

Combustion of drops and sprays of No. 2 diesel oil and its emulsions with water

Abstract: Experimental results on the combustion of unsupported single drops and pressure-atomized sprays of No. 2D oil and its emulsions with water are presented. The experiments covered the following range of variables: volume fraction of water=0–0.3; surfactant concentration =0–0.05; injection temperature=298–380 K; chamber temperature=400–950 K; chamber pressure=0.44 to 3.92 MPa; chamber inlet oxygen concentration=0.16–0.75; and spray injector nozzles=multihole and pintle. High speed motion photography was used to observe the flames of drops and sprays through quartz-windows. The films were analyzed to study the fragmentation behavior and flame geometry of single drops and the ignition delay and flame length of sprays. The exhaust gases of the test chamber were analyzed to determine the concentrations of CO2, O2, N2, NO, and NOx. The steady temperatures attained in the flames during spray burning were measured also. The results show that unsupported droplets of No. 2D diesel oil-water emulsions undergo disruption during combustion, and the fragmentation increases with water content, surfactant content, injection temperature, chamber oxygen concentration, and chamber temperature, but is not significantly dependent on chamber pressure. Also, the ignition delay increases considerably for volume fractions of water above 0.12. The flame temperature, exhaust emissions of NO and NOx, and oxygen utilization in the combustion chamber are complexly dependent upon the variables examined. These effects can be explained in terms of a physical model where the dominant combustion mode shifts from overall envelope flame to individual drop burning.

Cooling of High-Pressure Rocket Thrust Chambers with Liquid Oxygen

Abstract: An experimental program using hydrogen and oxygen as the propellants and supercritical liquid oxygen (LOX) as the coolant was conducted at 4.14 and 8.274 MN/square meters (600 and 1200 psia) chamber pressure. Data on the following are presented: the effect of LOX leaking into the combustion region through small cracks in the chamber wall; and verification of the supercritical oxygen heat transfer correlation developed from heated tube experiments; A total of four thrust chambers with throat diameters of 0.066 m were tested. Of these, three were cyclically tested to 4.14 MN/square meters (600 psia) chamber pressure until a crack developed. One had 23 additional hot cycles accumulated with no apparent metal burning or distress. The fourth chamber was operated at 8.274 MN/square meters (1200 psia) pressure to obtain steady state heat transfer data. Wall temperature measurements confirmed the heat transfer correlation.

Rotary vane pump with pressure biased flow directing end plate

Abstract: In a sliding vane type of rotary pump usable for power steering systems a seal of hour glass shape is provided between the flow directing plate, on the outlet side of the vane rotor and the outlet pressure chamber, to confine exposure of the high pressure of the outlet chamber to the downstream side of the plate within a predetermined area only partially balanced by exposure of the upstream side to such high pressure and to also isolate suction passages from the outlet chamber pressure. The result is a flexing of the flow directing plate at the center toward the pump rotor to reduce rotary clearance and permit the use of thinner and lighter weight flow directing plates.

Device for opening shellfish

Abstract: Shellfish are placed into a chamber which is brought rapidly to a high pressure. A lid of the chamber is magnetically sealed. The magnets are quickly released to allow the chamber pressure to blow off the cover with large springs absorbing energy. The immediate decompression causes the shellfish to open. A sonic or ultrasonic source within the chamber augments the process.

Etch end point detector using gas flow changes

Abstract: As etching progresses from one layer of material to another in reactive ion etching systems, the partial pressures of the reaction chamber gas components change. In constant pressure reactive ion etching systems, changes in chamber pressure are corrected by changes in the etchant species flow rate into the reaction chamber. By monitoring flow rate, information is obtained which may be used to identify the points where partial pressures change, and latter may, in turn, be used to derive etching points in the material being etched.

Control valve arrangement for combined brake cylinder and air reservoir device

Abstract: Brake apparatus for a railway vehicle including a brake cylinder device of the type having a pair of interconnected pistons of unequal size to which the vehicle brake rigging is connected. The larger power piston forms an application chamber and a release chamber on its opposite sides in which air is stored for use in controlling the vehicle brakes. The brake apparatus further includes a control valve device that is operative responsive to a reduction of brake pipe pressure to conduct flow of air from the release chamber to a positioning chamber formed on the side of the smaller positioning piston corresponding to the side of the power piston having the application chamber, to effect movement of the interconnected pistons to a brake application position. A transfer valve is actuated to connect this flow of air from the release chamber to atmosphere when the positioning chamber pressure exceeds, by a certain amount, a predetermined pressure at which the positioning piston is designed to move the power piston to application position. This certain amount by which the positioning chamber pressure is required to exceed the predetermined pressure, in order to actuate the transfer valve varies with the release chamber pressure effective at the time of a brake application.

Stop valve with leakage indicator - has switch pin bearing against diaphragm subject to measuring chamber pressure

Abstract: The stop valve has an indicator with a measuring chamber operating in the event of leakage past the plug. On shutting the valve this is sealed off and the pressure inside increased by reduction of the chamber volume. The chamber is connected via a passage through the valve seat to a monitoring unit. This unit (K) has a diaphragm (19) subject to the pressure in the measuring chamber (23), typically via the passage (16) through the valve seat, and against which a pin (21) bears, for the contactless actuation of a switch. The chamber below the diaphragm is connected by a passage to a sealed compensation chamber (22) of constant volume, pref. three times that of its own.

Method and apparatus for controlling communication with a compressor unloader chamber

Abstract: A compressor unloader system and method is disclosed, comprising a pneumatically controlled one-way valve member for controlling communication between an unloader chamber and a compression chamber of a compressor. The one-way valve member has one surface exposed to the pressure of the unloader chamber. To close it a control mechanism is actuated to present a lower pressure to an opposing second surface, interior of the valve member, creating a pressure differential to urge the one-way valve member toward a closed position. Temporary excesses of compression chamber pressures relative to unloader chamber pressures may bump the valve open to charge the unloader chamber with essentially maximum compression chamber pressure, thereby neutralizing the effect of the unloader chamber and fully loading the compressor. The one-way valve member is biased toward an open position. Thus, when the pressure differential is removed by exposing the second, opposing surface of the one-way valve member to the same unloader chamber pressure as that to which the first surface is exposed, the valve opens to unload the compressor. A method for controlling communication between an unloader chamber and a cylinder chamber of a compressor is also disclosed and claimed.

Explosion relief vent for cover of drying centrifuge etc. - carries pressure wave through flexible sleeve to exhaust duct

Abstract: A machine, partic. a drying centrifuge, has a processing chamber with access port closed by a cover. The improvement is that the cover has a pressure relief aperture leading into a connecting sleeve which joins into an exhaust duct. The cross sectional areas of the aperture, sleeve and duct are all sufficiently great to ensure that any explosion in the vessel is relieved before the chamber pressure can rise to a level which would damage the chamber or ancillary equipment. The sleeve is pref. made of a deformable material, partic. in pleated concertina formation. A bursting disc is pref. fitted somewhere between the access port and the outlet end of the exhaust duct. When the chamber or cover is provided with an observation port, a remotely controlled, closed circuit television camera is pref. used for viewing through the port window. Used to vent explosions to atmos. before pressure can damage the equipment. Partic. applicable to the safety covers or operator guards which now have to be fitted over the access ports of vertical axis centrifugal dryers. Chamber pressure is restricted to a predetermined safe value. The new type of cover can be rapidly and inexpensively fitted to existing plant.

Pressure compensated shaft seal

Abstract: Relatively-rotating face ring-type shaft seals, which are. especially suitable for sealing the shaft bearings and lubricant chamber of mud-motor-driven downhole drill rigs, have telescoped annular seal rings (123, 124) slidably mounted in a annular carrier element (122) and riding over the radial face on a face ring (112), defining a sealed intermediate chamber which may be filled with lubricant. Either the telescoped seal rings (123, 124) or the face ring (112) rotates with the bit shaft (15). Biasing means, such as a plurality of springs (143), urge the seal rings (123, 124) against the face ring (112) and pressure transmission means, such as pistons (152), mounted either in the carrier element (122) or the face ring (112) are loaded by the pressure of the ambient medium, such as drilling fluid, to maintain pressure in the intermediate chamber responsive to the pressure of the ambient medium. When the parts 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 seal ring (124), to prevent the ambient medium from entering the outer seal ring interface. The inner seal ring (123) serves as an auxiliary back-up face ring seal for the protected bearing chamber. Since the abrasive medium does not enter the interfaces of the rings, the end faces (123', 124') of the seal rings (123, 124) riding on the face ring (112) can be reduced or narrowed to a minimum and coated with a hard facing material such as tungsten carbide.

Air weft insertion nozzle control system

Abstract: The actuation of a nozzle utilized for propelling the yarn in an air weft insertion weaving system is controlled by means of a single rotary servo valve having an arrangement of ports adapted to be brought during valve rotation into registration alternately with an air pressure source and with the atmosphere for alternately pressurizing and venting a pilot chamber for opening and closing the nozzle. Preferably, the rotary valve includes a rotary spool enclosed within a sleeve of air permeable material to provide an air bearing for the spool. The actuation of the nozzle is determined by the movement of a diaphragm valve toward and away from the opening of a nozzle supply chamber under the control of the pilot chamber pressure, and the diaphragm is deformed into two annularly separated generally U-shaped convolutions opening toward the interior of the air supply chamber of the nozzle so that the movement of the diaphragm during opening and closing follows a "rolling" or progressively flexing action as the convoluting side walls telescope outwardly and inwardly relative to one another. Preferably, two substantially similar convoluted diaphragms are disposed in axially spaced oppositely directed relation, one exposed to the nozzle supply pressure and the other to the pilot chamber pressure. Advantageously, the interior space between such diaphragm is vented to the atmosphere to maintain a pressure-free condition therein and clearances are provided to prevent entrapment of air resisting deflection of either diaphragm.

High Frequency Instability in a Lox-Kerosene Rocket Combustor (Effects on Heat Transfer Augmentation)

Abstract: The high frequency instability of a JP-4 fuel and liquid oxygen rocket combustor, especially the effects of this instability on heat transfer augmentation to the chamber wall, was studied. The FOF triplet type injector element and two chambers with different lengths were used in the experiments. Both chambers delivered a 10kN thrust at a 3.5MPa chamber pressure. The pressure oscillation generated spontaneously was identified as being a longitudinal first mode. The ratio of rms pressure amplitude to average chamber pressure observed in unstable combustion was 0.23 at most. In order to obtain stable combustion or weak unstable combustion, a damping device based on Crocco’s theory of longitudinal high frequency instability was designed and used successfully. The heat flux to the wall increased six to seven times at most due to the instability. It was shown that the increase of the bulk heat transfer coefficient was proportional to the square root of rms pressure amplitude when the effective temperature, based on the frequency of oscillation, was used. Various considerations, including the effect of solid carbon particles, suggests that Dent’s model of convective heat transfer augmentation is more reasonably consistent with the experimental results than is Hanby’s model. The time average static pressure along the chamber axis increased downstream after it had first decreased. Theoretical analysis of the periodically oscillating one-dimensional flow showed reasonable agreement with the experimental results.

Interior Ballistic Evaluation of High-Flame Temperature Propellants in 20mm Ammunition and Assessment as an Erosion Test Device

Abstract: : Gun barrel wear tests have uncovered the need for a small scale device to test barrel treatments like 'thick' chromium. Small caliber barrels have traditionally served this role, but results with high-firing rates used to produce measurable wear are ambiguous. An ideal erosion test device would be a small caliber gun with standard projectiles, cartridge cases and propellants which would produce wear comparable to wear in large-caliber guns. Interior ballistic tests were done with M2 or M9 propellant in place of the standard ball powder in the M55A2TP-T round to determine charge masses which would not exceed the peak chamber pressure of the reference M55A2TP-T round. The wear produced with the high-flame temperature propellants was estimated with the Frankle-Kruse empirical formula. The results showed an M9 propellant could be loaded to the same charge mass as the reference WC870 ball powder with a lower peak chamber pressure but 100 m/s higher velocity. The wear estimated for such a round is 5 micrometer/shot, comparable to wear -limited Army guns, but less than the desired 25 micrometer/shot (1 mil/shot) for an erosion test device. Hence the 20-mm gun with M9 propellant could be useful for evaluating chromium-plating for existing guns, but it has too little wear for conveniently assessing future platings and coatings.

Method and device for treating moist wood

Abstract: The moist wood is exposed to high temperatures in a chamber (20). The high pressure arising in this connection in the wood as a result of the steam forming is counteracted by a counterpressure of 2 to 45 bar which is built up in the chamber. By slowly reducing the counterpressure, the steam can escape from the wood, without structural damage occurring in the wood. At the latest at the start of the reduction of the chamber pressure, which extends over a period of time of 10 to 180 minutes, a constant mechanical pressure of 1-150 bar is exerted on the wood until the end of its shrinking process by heatable plates (26, 30) by means of one or more piston rods (27) engaging thereon. The wood thus dried is extremely stable in terms of shape and dimension. It is suitable for example as shaft wood for guns which does not change its properties even when exposed to the most extreme environmental conditions for a long time.

Compressed air servo motor - has inlet and exhaust chambers separated by piston and pressurised prior to use

Abstract: The compressed air "suspended" servo motor has an air inlet chamber and an exhaust chamber sepd. by a piston. A high air pressure is maintained in both chambers when the servo motor is in its "ready for use" state. To operate the servo motor the pressure in the exhaust chamber is reduced relative to the inlet chamber to create a pressure differential across the piston. The pressure differential is controlled by a valve located in a piston passageway interconnecting the two chambers and which has an annular plunger operated by movement of an input rod to shut off the passageway. The plunger reacts against the input rod and has oppositely directed areas exposed to the exhaust chamber pressure to effect a balance on the plunger and to limit its nett reaction against the rod (18).