Showing papers on "Chamber pressure published in 1987"

Temperature and Concentration Measurements in a Solid Fuel Ramjet Combustion Chamber

Abstract: The combustion of solid fuels has been studied by using a solid fuel ramjet combustion chamber equipped with a vitiated air heater. The fuels were polyethylene (PE) and hydroxyl-terminated poly butadiene (HTPB), with PE being the prevailing fuel. The air was heated by combustion of hydrogen and oxygen. In order to get a better understanding of the combustion process, a thermocouple and a gas-chromatogr aphic technique were used to obtain temperature and species concentration profiles throughout the combustion chamber. The measurements were taken at several axial and radial positions of the combustion chamber, including measurements in the recirculation zone of the flameholder and in the afterburner chamber. The influence of different test conditions, like mixture ratio, inlet temperature, and mass flux, was also investigated. The results are discussed with regard to flame position, turbulent mixing, and combustion efficiency.

TEOS based plasma enhanced chemical vapor deposition process for deposition of silicon dioxide films.

Abstract: A high pressure, high throughput, single wafer, semiconductor processing reactor (10) is disclosed which is capable of thermal CVD, plasma-enhanced CVD, plasma-assisted etchback, plasma self-cleaning, and deposition topography modification by sputtering, either separately or as part of in-situ multiple step processing. The reactor includes cooperating arrays of interdigitated susceptor (16) and wafer fingers (20) which collectively remove the wafer (15) from a robot transfer blade (24) and position the wafer with variable, controlled, close parallel spacing between the wafer and the chamber gas inlet manifold (26) then return the wafer to the blade. A combined RF/gas feed-through device (36) protects against process gas leaks and applies RF energy to the gas inlet manifold without internal breakdown or deposition of the gas. The gas inlet manifold (26) is adapted for providing uniform gas flow over the wafer. Temperature-controlled internal and external manifold surfaces suppress condensation, premature reactions and decomposition and deposition on the external surfaces. The reactor also incorporates a uniform radial pumping gas system which enables uniform reactant gas flow across the wafer and directs purge gas flow downwardly and upwardly toward the periphery of the wafer for sweeping exhaust fases radially away from the wafer to prevent deposition outside the wafer and keep the chamber clean. The reactor provides uniform processing over a wide range of pressure including very high pressures. A low temperature CVD process for forming a highly conformal layer of silicon dioxide is also disclosed. The process uses very high chamber pressure and low temperature, and TEOS and ozone reactants. The low temperature CVD silicon dioxide deposition step is particularly useful for planarizing underlying stepped dielectric layers, either alone on in conjunction with a subsequent isotropic etch. A preferred in-situ multiple-step process for forming a planarized silicon dioxide layer uses (1) high rate silicon dioxide deposition at a low temperature and high pressure followed by (2) the deposition of the conformal silicon dioxide layer also at high pressure and low temperature, followed by (3) a high rate isotropic etch, preferably at low temperature and high pressure in the same reactor used for the two oxide deposition steps. Various combinations of the steps are disclosed for different applications, as is a preferred reactor self-cleaning step.

Cryo-slamming apparatus and method for ultrarapid cooling of biological samples

Abstract: A method and apparatus for ultrarapid cooling of tissue samples against a chilled cryogenic surface. The cryogenic surface is enclosed in a high vacuum chamber during cooling of the cryogenic surface. Dry non-condensable room temperature gas is introduced from an external source to raise the chamber pressure just prior to slamming or plunging a sample against the cryogenic surface. The cryogenic surface is heated for regeneration or cleaning purposes between each successive sample.

Laser-sustained plasmas in forced argon convective flow. I - Experimental studies

Abstract: The results of an experimental investigation of the properties of laser-sustained plasmas in argon at forced convective flow speeds of 0.4-4.5 m/s are reported in this paper. At these speeds, the incident flow rate has a significant effect on the shape, size, and position of the plasma, which in turn affect the power absorption, thermal radiation, and total energy conversion efficiency of the plasma. In addition to the incident flow rate, the focusing geometry, chamber pressure, and laser power were varied as parameters in the experiments. The thermal conversion efficiency was found to range 9-38%, depending on the various parameters.

A Discussion of the Effect of Chamber Pressure on Heat and Mass Transfer in Freeze-Drying

Abstract: There have been many reports concerning the influence of chamber pressure on primary drying times and sublimation rates of freeze-dried materials. However, there is disagreement about the mechanisms responsible for the observed effects. The complex interaction between system parameters and product nature, which may lead to the contradictory views expressed in the literature, are discussed. In particular, it is considered by the present authors that results derived from pure ice are not applicable to product in which a cake of residual solids is formed.

Performance of high-area-ratio nozzle for a small rocket thruster

Abstract: Theoretical estimates of supersonic nozzle performance have been compared to experimental test data for nozzles with an area ratio of 100:1 conical and 300:1 optimum contour, and 300:1 nozzles cut off at 200:1 and 100:1. These tests were done on a Hughes Aircraft Company 5 lbf monopropellant hydrazine thruster with chamber pressures ranging from 25 to 135 psia. The analytic method used is the conventional inviscid method of characteristic with correction for laminar boundary layer displacement and drag. Replacing the 100:1 conical nozzle with the 300:1 contoured nozzle resulted in an improvement in thrust performance of 0.74 percent at chamber pressure of 25 psia to 2.14 percent at chamber pressure of 135 psia. The data is significant because it is experimental verification that conventional nozzle design techniques are applicable even where the boundary layer is laminar and displaces as much as 35 percent of the flow at the nozzle exit plane.

Processing and packaging system for flexible containers

Abstract: An improved heating, packaging and sterilization system for pumpable particulate food product (e.g., soups, stews, fruits) is provided which makes use of an upstream pump and an automated packaging chamber maintained at superatmospheric pressure to achieve precise processing control without deleterious overcooking or flashing of the food product The upstream pump (20) is coupled to the chamber (14) via a constant diameter conduit (18) and the open delivery end of the latter is in direct communication with the pressurized interior of the packaging chamber; in this way the easily controllable chamber pressure provides back pressure within the product conduit, so that a substantially uniform decreasing pressure gradient and essentially plug product flow are established throughout the length of the conduit from the pump (20) to the chamber (14). Moreover, the chamber pressure is of sufficient magnitude to prevent flashing throughout the system. In practice, the packaging chamber is relatively small inasmuch as it is not intended to normally house plant personnel, and can accommodate either flexible web form, fill and seal packaging equipment (40) or conventional canning units. The product pump (20) is advantageously a dual piston food pump coupled with downstream steam-fed scraped surface heat exchangers (32).

Control mechanism for crank chamber pressure in swinging swash plate type compressor

Abstract: PURPOSE:To obtain a compression capacity according to a cooling load, by providing a control valve for controlling a restriction of a relief passage communicating a crank chamber with a suction chamber. CONSTITUTION:A control valve 29 is provided in a rear housing 3 to control the pressure in a crank chamber 13. A control valve 41 is provided in blow-bay gas relief passages 28A and 28B communicating the crank chamber 13 with a suction chamber 6. A communication passage 42 is variably restricted by the control valve 41. Accordingly, an inclined angle of a wobble plate 21 may be varied with a little amount in a swing direction according to a reduction in cooling load, thereby obtaining a desired compression capacity.

A Bench-Scale Aerosol Test Chamber

Abstract: This paper describes the design and evaluation of a bench-scale aerosol test chamber. Although originally designed for respirator testing, the chamber has broad applications for industrial hygiene research, testing, and calibration. The 109 L chamber includes a top mixing section, a honeycomb flow laminator section, a 52 L transparent plastic aerosol test section, and a bottom exhaust plenum. Overall chamber dimensions are 0.6 × 0.6 × 1.5 m high. Airflow velocity was uniform within ± 20% of the mean throughout the test section. A uniform aerosol concentration was achieved in the test section by opposed jet mixing in the mixing section. Test aerosol concentrations in the chamber were uniform within ± 15%, and concentration was stable to within ± 5% for more than one hour. Measurements were made with a GCA Model RAM-1 instrument and based on perpendicular 8-point traverses. Similar uniformity (within ± 5%) was found for 12 μm and 24 μm monodisperse particles. Chamber pressure can be controlled from...

Method for increasing the amount of powder delivered to a powder-coating apparatus, and powder-coating apparatus

Abstract: In a powder coating plant, wherein the powder through a feed line (3, 32) of an input of a mixing chamber (5, 55) is supplied, is moved along the feed line (3, 32) through acceleration of a gas radiator in the mixing chamber (5, 55) a directed against the chamber pressure gradient generated and scored pressure recovery by delaying the powder-gas stream to the powder-gas stream duch a conveying line (11) of a coating assembly (21) zuzuspeisen. To increase per unit time of the powder coating system output (21) Powder amount of pressure drop in the powder-gas stream along the conveying line (11) by increasing the pressure at the input is at least partially compensated.

Improvements relating to gas compressors.

Abstract: A piston and cylinder air compressor has unloader valve signalled to overcome a spring bias by air pressure at a port 27, indicative that a desired charge pressure has been attained in a reservoir, to open a path between the compression chamber 6 and the inlet chamber 12, the unloader valve having a pressure responsive area subject to compression chamber pressure and acting in a sense to enhance the spring bias.

Multiple-stage rocket motor nozzle throat

Abstract: The invention is concerned with reducing the effect of a progressive surface area versus web thickness relationship in a rocket motor and is particularly useful with center perforate propellant grains where the chamber pressure versus time history is generally progressive. In a very short action time rocket motor, it is desirable to keep the chamber pressure as close as practical to the peak during the entire burn to increase the propellant burn rate. The multiple-stage throat makes this possible in a motor that uses the cost effective center perforate propellant grain design and operates by allowing a first stage throat to erode at a predictable rate while the area of the propellant burning surface is increasing. The motor initial Kn (propellant surface area divided by nozzle area) is raised by using a relatively small initial size for the first stage throat and as a result the rocket motor reaches peak chamber pressure quickly. With the erosion of the first stage matching the increasing propellant surface area the chamber pressure remains nearly constant. Near the end of the burn the first stage throat erodes out to the diameter of a non-eroding second stage throat which then becomes the controlling throat.

Carbon deposition characteristics of LO2/HC propellants

Abstract: The generation and deposition of carbon have been studied using subscale hardware with LO2/RP-1, LO2/propane, and LO2/methane at low mixture ratio conditions. The deposition of carbon on the turbine simulator tubes was evaluated at mixture ratios of 0.20 to 0.60, and at chamber pressures from 720 to 1650 psia. The carbon-deposition rate is a strong function of mixture ratio and a weak function of chamber pressure. There is a mixture ratio that will minimize deposition for LO2/RP-1; a threshold mixture ratio for LO2/propane; and no deposition for LO2/methane at any mixture ratio tested. The turbine drive operating limits were defined for each fuel tested.

Slip control device for lockup torque convertor

Abstract: PURPOSE:To make a gear change shock small by reducing line pressure when there is occurring a drop in the pressure of a lockup control chamber because of slip control at the time of a gear change. CONSTITUTION:Slip control for a transmission causes a drop in lockup control chamber pressure PL, but a pressure switch 36 is turned ON, thereby reducing an input to a reversing amplifier 34 to a lower level, controlling a solenoid 31a and causing a solenoid valve 31 to open a drain port 30. Consequently, there occurs a drop in throttle pressure directed from the throttle circuit 42 to the pressure regulator valve 41, and line pressure also gives a drop. The capacity of a frictional element to be actuated on the line pressure at the time of a gear change is thereby caused to decrease and peak torque an inertia phase can be made small, thereby enabling the reduction of a gear change shock.

Gas generation with high pressure sensitivity exponent propellant

Abstract: Gas generator apparatus usable with a ducted rocket propellant having a high exponent burn rate, a burn rate that is burn chamber pressure sensitive to a greater degree than are normally used propellants. The gas generator includes elementary pressure regulating elements and apparatus for damping movement of the pressure regulating elements to remove oscillatory components of motion therefrom. Burn rate operating point determination and the stability characteristics thereof are described along with the effects of variations in propellant burn rate exponent and regulating element parameters.

Technical note: Cryogenic vacuum pump characteristics in reactive d.c. magnetron sputtering processes

Abstract: Cryogenic vacuum pumping has become an accomplished fact in reactive d.c. magnetically enhanced sputtering processes. Thin film requirements have become more stringent with respect to deposition parameter control and reproducibility focusing attention on the operating characteristics of the vacuum pumps commonly used on modern sputtering systems. TiO x films reactively sputtered from a metal target have been deposited in an argon-oxygen mixture by varying the O 2 partial pressure. The purpose of this study is to investigate the effect of pumping system characteristics using a standard CVI TM150 size cryogenic pump on the profile of the cathode discharge with respect to O 2 percentage. TiO x films were deposited reactively at discharge power levels of 1.0 kW, 2.0 kW and 4.0 kW respectively for P tot levels of 1.0 mTorr and 2.0 mTorr. A direct comparison with oil diffusion pumping was obtained by replacing the cryogenic pump with a Varian VHS6 oil diffusion pump and repeating the test depositions at the previously stated discharge power levels. Other ancillary pumping system parameters for both the cryogenic pump and the oil diffusion pump were obtained. They include pumpdown characteristics, argon flow rate with respect to chamber pressure, residual gas spectra with respect to argon partial pressure and chamber variation with respect to oxygen percentage with constant argon flow rates.

Apparatus for quantitatively and automatically supplying liquefied gas under constant pressure

Abstract: PURPOSE: To continuously supply liquefied gas to a filling line where a liquefied gas cylinder can not be carried-in, by providing a pressure control means and a liquid level detector to the upper and lower chambers of a heat insulating liquefied gas container and controlling an opening and closing valve and a valve mechanism on the basis of a liquid level signal CONSTITUTION: A solenoid valve 33 is operated by the detection signal of the first liquid level detector 44 and the liquid level of the liquid nitrogen in an upper chamber 31a is held within a set range and, when pressure is judged to be high by an upper chamber pressure detector 46, a solenoid valve 47 is opened and, when said pressure is low, a solenoid valve 48 and a self-supporting type pressure control valve 49 are opened A solenoid valve 52 is controlled by the second liquid level detector 51 in a lower chamber 31b to hold a liquid level within a set range When pressure is judged to be high by a lower chamber pressure detector 54, a solenoid valve 56 or a pressure control valve 55 is operated so as to be opened and, when said pressure is low, a pressure control valve 57 for pressurization is opened to introduce the nitrogen gas of the outside A definite amount of the nitrogen gas is always introduced under pressure from the pressure control valve 57 and pressure variation or the reduction and change in the pressure of the lower chamber 31b at the time of lowering in a liquid level is corrected to keep the pressure in the lower chamber 31b constant COPYRIGHT: (C)1988,JPO&Japio

Clutch operation control device for fluid torque converter

Abstract: PURPOSE:To prevent the temperature rise without lowering the gripping force of a clutch, by forming a communication passage provided with a relief valve for back pressure between a vane wheel housing chamber in the torque converter and a clutch disc back pressure chamber and simultaneously by forming a drainage in parallel with a relief valve for housing chamber pressure. CONSTITUTION:In a slipping condition of a clutch 20 an oil temperature in a housing chamber 21 comes to be apt to rise by a relative rotation between vane wheels 17, 18 but an oil in the housing chamber 21 is drained from a drainage LD2, bypassing a relief valve 25 for housing chamber pressure. Consequently the circulation of an oil is improved and the rise of an oil temperature is prevented. On the other hand, in the connecting condition of the clutch 20 directional control valves 23, 29 shift leftward to cut off between the drainage LD2 and an oil passage L13 and consequently to the housing chamber 21 on the primary side of the clutch 20 a hydraulic pressure set by the relief valve 25 and to the back pressure chamber 22 of the clutch 20 a pressure close to the atmospheric pressure since an oil passage L9, an oil passage L12 and a drain port 28b are communicated with each other, are applied, therefore a sufficient gripping force of the clutch 20 can be gotten.

Plasma Diagnostics for a Low-Pressure Plasma Spray Deposition System

Abstract: Measured plasma temperature and particle velocity distributions in a Low-Pressure Plasma Spray (LPPS) system show a strong dependence on process chamber pressure over the range of 50 to 600 Torr. Plasma temperatures of 3000 to 12,000 K were calculated from argon atomic emission spectra by the Boltzmann slope method. Peak particle velocities up to 365 m/s were measured with a laser velocimeter for 44 ..mu..m Al/sub 2/O, spray particles. Our results indicate that there may be potential benefits to operating a LPPS system at pressures on the order of 300 Torr.

On-line learning control method for deposition amount in continuous vacuum deposition device

Abstract: PURPOSE:To uniformly control the vapor deposition thickness in the widthwise direction of band steel by using a learning vapor deposition chamber pressure coefficient obtained from the actual and theoretical values of the Zn vapor deposition chamber pressure when the metallic vapor-deposited layer of Zn, etc., is formed on the surface of band steel by a continuous vacuum deposition device. CONSTITUTION:The band steel 1 is continuously transferred by a rolling roller 4 from (a) to (b) in a vapor deposition chamber 3, a molten Zn bath 6 in an evaporation vessel 5 is heated by a heater 9 and evaporated, and the obtained vapor is passed through a duct 8 provided with a shutter 11 and a film thickness distribution controlling plate 15 to vapor- deposit Zn on the surface of the band steel. The stability of the Zn deposition control system of the device is judged. When the system is stabilized, the actual data such as the deposition amt. and a line velocity are collected, the ratios of the actual vapor deposition chamber pressure PX obtained by the inverse calculation from the data to the theoretical vapor deposition chamber set pressure PO, namely the learning vapor deposition chamber pressure coefficient CP=PO/PX, are statistically processed into a data table stratified in accordance with the specifications of the band steel, and stored in an arithmetic unit 23. A vapor deposition pressure setting calculation equation is adjusted on a line by using the values of CP, and reflected on the succeeding pressure setting. The Zn vapor deposition amt. in the widthwise direction of the band steel is thus uniformized.

Mechanism for returning swing slant angle of wobble plate in swing swash plate type compressor

Abstract: PURPOSE:To enable a wobble plate to be securely pivoted by providing a control valve for changing the sectional area of an escape path affording communication between a crank chamber and an intake chamber according to a change in crank chamber pressure. CONSTITUTION:In an escape path 28 affording communication between a crank chamber 13 and an intake chamber 6 is provided a control valve 41 for changing the sectional area of said path 28. On an end of a switch valve 48 of the control valve 41 is provided a diaphragm 42 into one side of which is introduced pressure in the crank chamber 13 through a crank pressure chamber 44. Thus, as pressure in the crank chamber 13 changes, the diaphragm 42 is displaced to change a distance between an end of the switch valve 48 and a valve seat, the sectional area of the escape path 28 and an escape amount of blow-bye gas in the crank chamber 13 so that a wobble plate 21 can be securely pivoted.

Measuring device for fuel injection quantity

Abstract: PURPOSE:To measuring suitably the fuel injection quantity by providing a fuel volume detecting part having a means for detecting a displacement quantity of a diaphragm, and a back pressure chamber pressure holding means, etc. CONSTITUTION:The quantity of fuel which has been to a fuel jet chamber 36 of a fuel volume detecting part 1 is detected by a displacement of a diaphragm 31. A back pressure chamber 37 of this fuel volume detecting part 1 is held by a prescribed pressure by a back pressure chamber pressure holding device (a safety valve 47, etc.), and connected to the fuel jet chamber 36 through the diaphragm 31. As a result, when a fuel jet is executed to the fuel jet chamber 36 from a fuel jet valve 24, the diaphragm 31 is displaced in accordance with the jetted fuel quantity, namely, its volume, but even if the diaphragm 31 is displaced, the pressure of the fuel jet chamber 36 is not varied. Accordingly, the displacement quantity of the diaphragm 31 corresponding to the fuel quantity of the fuel jet which is executed by keeping the pressure (back pressure) of the fuel jet chamber 36 constant is detected by a displacement quantity detecting means (a transmission part 55, etc.), and by executing an operation, based on this displacement quantity, the fuel jet quantity can be measured suitably,.

Metallic mold driving gear for glass lens molding device

Abstract: PURPOSE:To set desired conditions easily and surely and to prevent the generation of defects in precision on the molded lens by providing a holding shaft for supporting a movable metallic mold, a means for reciprocating the shaft, and a pressurizing means. CONSTITUTION:A pulse motor 33 is driven in association with the carrying-in of glass 20 to be molded, and a ball screw 36 is turned to lift a nut 37 along a guide shaft 31. A cylinder 42 is raised along with the ascension of the unit 37. Since a piston rod 43 is separated from the upper dead point by the ascension of the cylinder 42, a movable metallic mold holding shaft 10 and the lower die 12 can be lifted by the pressure in the cylinder. When the pulse motor 33 is stopped immediately after the upper and the lower die 6 and 12 are brought into contact with the glass 20 to be molded, the ball screw 36 is turned by the inertia of the motor, and the nut 37 and the cylinder 42 tend to be lifted. Meanwhile, since the lower chamber of the piston rod 43 in the cylinder 42 is connected to a regulator 17 to fix the pressure in the chamber, an increase in the chamber pressure is corrected when the case of the cylinder 42 is lifted.

Method for processing chamber pressure control

Abstract: PURPOSE:To cut down the pressure control time by controlling the timing of opening and closing two valves of a leading-in valve and a pressure control valve. CONSTITUTION:Before an etching process is started, a reaction chamber 1 is highly vacuumized up to the high vacuum pressure of P0. As soon as the etching process is started, a variable motor-driven valve 3 is fully closed simultaneously opening a process gas leading-in valve 4 to lead-in process gas 4'. When the pressure in reaction chamber 1 reaches the primary shift starting pressure P1, the variable motor-driven valve 3 is opened up to the opening V0 arbitrarily set up previously. Later, the feedback control by the signals from a pressure sensor 5 in the reaction chamber 1 is started to fit the pressure in reaction chamber 1 to the set up pressure P2. Through these procedures, the throughput of etching device can be increased since the reaction chamber 1 can be pressurized rapidly cutting down the required time for reaching the set up pressure P2 by fully closing the variable motor-driven valve 3 before leading-in process gas.