Showing papers on "Chamber pressure published in 1989"

Composite cartridge for high velocity rifles and the like

Abstract: A plastic cased metal headed ammunition casing for high powered rifle cartridges is described in which the plastic case (12) has a pressure regulating baffle or wall (44) in the forward end thereof to regulate and control the development of chamber pressure induced movement of the bullet (10) into the rifle barrel. The cartridge is charged with a given charge of powder (38) and the cap or head (14) securely fastened to the rearward portion of the plastic casing (12). The head (14) provides sufficient resistance to the residual pressure after firing so that the cartridge can be used in rapid fire automatic weapons.

Excimer laser output control device

Abstract: An excimer laser including a discharge chamber containing a mixture of halogen, rare gas and buffer gas uses two gas sources to replenish the halogen in the discharge chamber while maintaining the concentrations of all the gases at the optimum levels. One of the gas sources, source A, contains a mixture of the rare gas and the buffer gas in optimum concentrations. The other gas source, source B, contains both the rare gas and the buffer gas, in optimum relative concentrations, and also the halogen, in a concentration which is greater than optimum. As the laser operates and the gain of the laser decreases due to halogen depletion, gas from source B is injected into the discharge chamber to raise the halogen concentration. Gas is then released from the chamber to reduce the chamber pressure to the original level. When halogen replenishment does not suffice to restore the laser gain, due to the build-up of contaminants in the chamber, a portion of chamber gas is released and it is replenished with fresh gas from both sources in proportions adequate to provide optimum concentrations of the various gases.

Slant plate type compressor with variable displacement mechanism

Abstract: A slant plate type compressor with a capacity or displacement adjusting mechanism is disclosed. The compressor includes a housing having a cylinder block provided with a plurality of cylinders and a crank chamber. A piston is slidably fitted within each of the cylinders and is reciprocated by a drive mechanism which includes a member having a surface with an adjustable incline angle. The incline angle is controlled by the pressure in the crank chamber. The pressure in crank chamber is controlled by control mechanism which comprises a passageway communicating between the crank chamber and a suction chamber, a first valve device to control the closing and opening of the passageway and a second valve device to control pressure in an actuating chamber. The first valve device includes a bellows valve element and a valve shifting element. The valve shifting element of which one end is exposed in the actuating chamber is coupled to the bellows to apply a force to the bellows at another end and thereby shift a control point of the bellows in response changes in the actuating chamber pressure.

Electric impedance cuff for the indirect measurement of blood pressure and volume elastic modulus in human limb and finger arteries.

Abstract: A new plethysmograph, the electric impedance cuff, was designed for the indirect measurement of blood pressure, volume elastic modulus Ev and compliance Ca in human limb arteries. This comprises a compression chamber filled with electrolyte solution and a tetrapolar electric impedance plethysmograph whose electrodes are placed inside the chamber; the former for controlling transmural arterial pressure Pt, and the latter for detecting total limb volume Vo, mean arterial volume $$\bar V_a $$ and its variation ΔVa. Systolic and mean arterial pressure in the upper arms, forearms and fingers were measured by detecting pulsatile impedance variation during the gradual (3–5 mm Hg per heart beat) increase (or decrease) in chamber pressure by the volume oscillometric technique. Diastolic and pulse pressure ΔP were calculated from these pressure values. Compliance Ca=ΔV/ΔP and volume elastic modulus $$E_v = \Delta P/(\Delta V_a /\bar V_a )$$ were recorded at various Pt levels, controlled by the compression pressure. Although this is a kind of impedance plethysmograph, the volume change in a limb segment can be detected by this method without passing electric current through the limb.

Supply of controlled, medium-pressure CO2 gas in simple, convenient disposable packaging

Abstract: A gas generator chemically generates a gas from a chemical reaction between two reagents contained within a common container. The reagents are normally separated by a gas generation chamber into different regions of the container in the absence of gas generation therein. A reference pressure source of a predetermined pressure forces the two reagents into contact with each other when the pressure of gas in the gas generation chamber is less than the predetermined pressure. A valve in fluid communication with the gas generation chamber is provided to withdraw the generated gas from the chamber when OPEN. As the gas flows through the valve from the chamber the gas pressure in the chamber drops permitting more mixing of the reagents. When the chamber pressure becomes equal to or higher than the predetermined pressure applied by the reference pressure source, the reagents become separated again and gas generation ceases.

Reciprocating piston compressor with variable capacity machanism

Abstract: A wobble plate type compressor with a variable capacity mechanism is disclosed. Changing the displacement of a cylinders and therefore the capacity of the compressor is accomplished by varying the angle of an inclined surface of the wobble plate. This angle is varied by changing the difference in pressure between the crank chamber and the suction chamber. This pressure difference is controlled by changing the suction chamber pressure while uniformly maintaining the crank chamber pressure. In one embodiment the capacity varying mechanism includes a bellows. In another embodiment the capacity varying mechanism includes an electromagnetic valve and an electronic pressure sensor.

Pneumatic die cushion equipment

Abstract: A closed type cylinder unit, instead of the open-to-atmosphere type cylinder unit of conventional equipment forms part of the die cushion apparatus. Based on the principle that the die cushion capability by the closed type cylinder unit is determined by the differential pressure between the lower chamber pressure and the upper chamber pressure, the differential pressure is controlled in such manner that the lower chamber and the upper chamber communicate with each other through a check valve, which is opened when the differential pressure exceeds a preset differential pressure value. As the upper and lower chambers communicate through a shut-off valve, which hinders the excessive increase of the upper chamber pressure when the piston goes up. Further, the form of the check valve is changed for conveniently changing and adjusting the die cushion apparatus during press fabrication.

Steady-state permanent magnet magnetoplasmadynamic thruster

Abstract: A steady-state 10-kW -range magnetoplasmadynamic (MPD) thruster with permanent magnets has been made. The effect of the permanent magnets on thruster performance (specific impulse and thrust efficiency) and plasma-accelerating mechanism were examined through measurements of thrust, chamber pressure, current densities, and plasma properties in the exhaust plume. Nomenclature At = cross-sectional area of nozzle throat Cf = thrust coefficient g = gravitational constant Id = discharge current /sp = specific impulse J = current per unit axial length m = propellant mass flow rate N = plasma number density Pa = ambient pressure Pc = arc chamber pressure T = thrust Ta = aerodynamic force Te = electron temperature Tm = electromagnetic force related to applied magnetic field Ts = self-magnetic force Vd = discharge voltage Vs = space potential Z = distance from throat center 77 = thrust efficiency

Measurements of the Rate of Gas Diffusion in Rigid Cellular Plastics

Abstract: This paper describes a method for measuring gas diffusion through cellular plastics A specimen is placed in a chamber, which is then scaled and pressur ized with the test gas. The pressure increase causes some gas to enter the specicmen, and this entry results in a reduction of the chamber pressure By following the change in chamber pressure with time an appropriate transport characteristic for the material is determinedAn application of this method to a core specimen of an extruded polystyrene board is presented.

Use of an Expansion Tube to Examine Scramjet Combustion at Hypersonic Velocities

Abstract: Combustion testing at total enthalpy conditions corresponding to flight Mach numbers in excess of 12 requires the use of impulse facilities. The expansion tube is the only operational facility of its size which can provide these conditions without excessive oxygen dissociation or driver gas contamination. Expansion tube operation is described herein and the operational parameters having the largest impact on its performance are determined. These are: driver-to-intermediate chamber pressure ratio, driver gas molecular weight and specific heat ratio, and driver gas temperature. Increases in the last-named parameter will markedly affect the test section static pressure. Preliminary calibration tests are discussed and test gas conditions which have been achieved are presented. Calculated and experimental test times are compared and the parameters affecting test time are discussed. The direction of future work using this important experimental tool is indicated.

Hot chamber pressure die casting of magnesium alloys - using several hot chamber casting units connectable to various closable inlets on side of permanent cold mould

Abstract: Hot chamber pressure die casting machine consists of several casting units (7,32,33) including a furnace (8), crucible (11), casting container (14) and injection cylinder (18) which can move vertically up the side of a permanent mould (6) provided with a closure force compatible with a cold chamber die casting machine. The cylinders of each unit are controlled in unison and can inject metal into any of the casting holes present along their vertical path, viz. (22 to 25; 34-38, 39-43). Each casting unit is located in a lifting base (22) with each box independently operated. Each unit is fixed to the mould half (6) by bolts (23-29). USE/ADVANTAGE - Esp. for casting Mg and its alloys into thin walled components of large area and weight. The closure force of approx. 3000 MT enables large areas up to 20000 cm and weights of 1.8 Kg to be produced.

Rupture disc monitor

Abstract: This invention relates to an apparatus and process for detecting gas permeability in a main rupture disc which is in gaseous communication with a vessel. The process comprises: fitting a chamber over and in gas-tight association with the outside surface of the main rupture disc; selecting a burst presure for the main rupture disc and a set pressure; obtaining a gaseous pressure within the chamber which is greater than the normal operating pressure within the vessel, and equal to the difference between the set pressure and the burst pressure of the main rupture disc; and monitoring the chamber pressure for a decrease thereof. The apparatus comprises, generally, a chamber, a means for obtaining a gaseous pressure within the chamber, and a means for monitoring a change in pressure in the chamber.

Results of a preliminary, high power RF thruster test

Abstract: The objective of this program was to demonstrate a high power electrodeless, RF electric propulsion concept. This was successfully accomplished. No attempt was made to optimize the design of the thruster with regard to physical dimensions, mass flow, nozzle shape, operational frequency, or power level. Measurements made were chamber pressure, total and static pressures at the nozzle exit plane and exhaust tank pressure. Mass flows range from about 0.4 to 1 gm/sec and, assuming perfect gas relationships, specific impulses up to 580 sec were obtained. Typical chamber pressure was 300 torr exhausting to a tank pressure of about 10 torr. Working fluids used were argon, helium and mixtures of the two. No degration of the device was detected after 12 start/stop cycles, about three hours of total run time, and a maximum input power of 70 kW. 10 refs.

Pathlength control system with deformable mirror having liquid-filled housing

Abstract: A liquid filled pathlength control device is disclosed that responds to a pathlength control signal for adjusting the pathlength in an optical signal process dependent on coherent light. The liquid filled pathlength control device has a housing containing a liquid filled chamber. The liquid filled chamber has an extendable wall having an inner surface subject to pressure from the liquid. An external mirrored surface on the extendable wall is inserted into and the light path. The liquid filled chamber has a deformable wall having an inner surface subject to the pressure of the liquid and an external surface. A displacement transducer is coupled to the deformable wall and responds to a control signal of a first polarity to deflect the internal surface of the deformable wall in a first direction to increase the pressure of fluid in the chamber. The displacement transducer responds to a control signal of a second polarity to deflecting the internal surface of the deformable wall in a second direction to decrease the pressure of fluid in the chamber. A control means samples coherent light from the light path and provides a control signal to the displacement transducer to optimize the intensity of the beam. A transducer responds to fluid pressure within the liquid filled chamber to provide a signal proportional to the chamber pressure and therefore proportional to the mirror displacement.

Vent valve device

Abstract: A vent valve device having a pair of diaphragm-type piston members forming a pilot chamber therebetween. The one piston controls a vent valve via which brake pipe pressure is vented locally, while the other piston controls a pilot valve a control venting of the pilot chamber. A breather choke between the pilot chamber on one side of the other piston and a control chamber on the opposite side establishes a predetermined pressure differential thereacross only when brake pipe pressure supplied to the pilot chamber is reduced at an emergency rate to thereby actuate the other piston to a position opening the pilot valve. In addition, this other piston operates a cut-off valve to isolate the pilot chamber from brake pipe pressure so that the pilot valve quickly exhausts pilot chamber pressure. The one piston controlling the vent valve is in turn actuated by the exhaust of pilot chamber pressure to positively effect an unrestricted, local reduction of brake pipe pressure via the vent valve when this one piston is actuated.

Process for making preforms

Abstract: The invention relates to a process for the production of mouldings and structural elements, in which the substrate and a layer sprayed thereon are bonded to one another by the high-temperature isostatic moulding process and layers more than 5 mm thick are sprayed onto the substrate at a temperature of at least 600 DEG C by means of plasma spraying at a chamber pressure of 140 - 180 mbar, which is adjusted to at least 10 mbar after evacuation of the chamber , and the layer is bonded to the substrate diffusively and without pores by the high- temperature isostatic moulding process at at least 500 DEG C and at least 500 bar.

Liquid Oxygen Cooling of Hydrocarbon Fueled Rocket Thrust Chambers

Abstract: Rocket engines using liquid oxygen (LOX) and hydrocarbon fuel as the propellants are being given serious consideration for future launch vehicle propulsion. Normally, the fuel is used to regeneratively cool the combustion chamber. However, hydrocarbons such as RP-1 are limited in their cooling capability. Another possibility for the coolant is the liquid oxygen. Combustion chambers previously tested with LOX and RP-1 as propellants and LOX as the collant demonstrated the feasibility of using liquid oxygen as a coolant up to a chamber pressure of 13.8 MPa (2000 psia). However, there was concern as to the effect on the integrity of the chamber liner if oxygen leaks into the combustion zone through fatigue cracks that may develop between the cooling passages and the hot gas side wall. In order to study this effect, chambers were fabricated with slots machined upstream of the throat between the cooling passage wall and the hot gas side wall to simulate cracks. The chambers were tested at a nominal chamber pressure of 8.6 MPa (1247 psia) over a range of mixture ratios from 1.9 to 3.1 using liquid oxygen as the coolant. The results of the testing showed that the leaking LOX did not have a deleterious effect on the chambers in the region of the slots. However, there was unexplained melting in the throat region of both chambers, but not in line with the slots.

Rotary rolling piston type compressor

Abstract: A rotary rolling piston compressor having a hermetic shell in which a cylinder is fixedly mounted. A rolling piston is driven by a crankshaft supported by a bearing pair and carried by the rotor of an electric motor whose stator is fixed internally to the shell. The cylinder has a radial slot in which a vane reciprocates. The vane defines compression and suction chambers, limited axially by the internal faces of the bearings and the chambers having discharge and suction orifices, respectively. The internal face of at least one of the bearings is provided with a groove with one end in communication with the compression chamber and the part on the suction chamber side of the vane in communication with a recess provided on the radial slot surface, on the suction chamber side. The recess extends transversely to the direction of the reciprocating displacement of the vane. This arrangement causes the compression chamber pressure to be transmitted to the vane face turned to the suction chamber, while lubrication of this same side of the vane with the oil held within the groove and coming from the compression chamber is promoted.

Transpiration And Regenerative Cooling Of Rocket Engine

Abstract: Transpiration cooling extends limits of performance. Addition of transpiration cooling to regeneratively-cooled rocket-engine combustion chamber proposed. Modification improves performance of engine by allowing use of higher chamber pressure. Throat section of combustion-chamber wall cooled by transpiration, while chamber and nozzle sections cooled by fluid flowing in closed channels. Concept applicable to advanced, high-performance terrestrial engines or some kinds of industrial combustion chambers. With proper design, cooling scheme makes possible to achieve higher chamber pressure and higher overall performance in smaller engine.

Apparatus for collecting and removing paint lye sludge produced during the chamber pressure-water cleaning of building areas

Abstract: The apparatus for collecting the dirty water produced during the chamber pressure-water cleaning of building areas has a collecting container (11) with a dividing wall (12) which extends over its height and subdivides it into a low-pressure chamber (14, 23) connected to a suction fan (15) and into a sucking-off chamber (26) and which ends, at least in sections, at a distance from the bottom (34) of the collecting container (11), so as to form an undercurrent weir. A sucking-off tube (27) which ends above the undercurrent weir (25) and is connected to a sucking-off pump (28) is arranged in the sucking-off chamber (26). A filter basket (19) with filter elements (20) inserted on the wall and floor side is exchangeably provided in the low-pressure chamber (14, 23) under the inlet (13) for the dirty water and at a distance above the undercurrent weir (25), the filter basket separating an upper dirty-water inlet space (14) from a lower filtration-water space (23) such that all of the dirty water passes into the filter basket (19). As a result of the liquid closure at the bottom of the collecting container (11) by the filtration water, low-pressure chambers (14, 23) and sucking-off chamber (26) are separated from one another, so that the filtration water cleaned by the filter elements (20) of the filter basket (19) can be carried away without difficulty by means of the pump (28) continuously through its conveying connection (29) and via a hose into the sewage network as sewage which conforms to the regulations.

Improved cryo-slammer

Abstract: A method and apparatus for ultrarapid cooling of tissue samples against a chilled cryogenic surface. The cryogenic surface (20) is enclosed in a high vacuum chamber (21) during cooling of the cryogenic surface. Dry non-­condensable room temperature gas is introduced from an external source (50) 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 cleaing purposes between each successive sample.

Variable focus type reflection mirror

Abstract: PURPOSE:To vary the focal length of the reflection mirror continuously without replacement by providing a shell consisting of a pressure chamber and a reflection mirror holding part, a chamber pressure controller, and the reflection mirror which is varied in focal length by changing the reflection mirror into various parabolic surfaces with the pressure in the pressure chamber CONSTITUTION:For a concave reflecting surface 13a, an electromagnetic operation valve 10a is closed through the operation of a control part 12 and an electromagnetic operation valve 10b is opened to connect the pressure chamber 5 to a vacuum pump piping system 9b, thereby producing negative pressure by a vacuum pump 11b The reflection mirror 4, therefore, flexes toward the pressure chamber 5 to have the concave reflection mirror 13a For a convex reflection mirror 13b, on the other hand, the electromagnetic operation valve 10a is opened and the electromagnetic valve 10b is closed through the operation of the control part 12 to connect the pressure chamber 5 to a compressor piping system 9a, thereby producing positive pressure by a compressor 11a The reflection mirror 4, therefore, flexes to the opposite side from the pressure chamber 5, thereby forming the convex reflecting surface 13b When the focal length is varied, the replacing mirror 4 need not be replaced

Method and apparatus for determining the degree of ventilation of stick-shaped articles of the tobacco-processing industry

Abstract: To determine the degree of ventilation of stick-shaped articles (3) of the tobacco-processing industry which have a ventilation zone of desired air permeability, the articles are conveyed in succession through a test station (6). The ventilation zone (16) of the articles is surrounded in the test station by a pressure chamber (17), to which a chamber pressure different from atmospheric pressure is applied from a pressure source (18). At one article end, the pressure is measured by means of a pressure transducer (13), and a test-pressure signal (PP) corresponding to the degree of ventilation of a cigarette is generated. At the same time, the chamber pressure in the pressure chamber (17) is measured by a pressure transducer (19), and a chamber-pressure signal (PK) is generated. In an evaluation circuit (21), the quotient of the test-pressure signal (PP) and the chamber-pressure signal (PK) is formed and is multiplied by the factor 100, a degree-of-ventilation signal V being obtained, the latter giving the degree of ventilation directly as a percentage. This procedure is particularly suitable for measuring the degree of ventilation in filter cigarettes.

Hydrogen peroxide plasma sterilization method

Abstract: PURPOSE: To achieve sterilization of the products by treating them with hydrogen peroxide without plasma, following which by treating them with plasma for removing the residual traces of hydrogen peroxide. CONSTITUTION: The subjects, i.e., products to be sterilized are placed either into a vacuum vessel or plasma chamber, where the chamber pressure is then reduced down to about 0.05Torr. The aqueous solution of hydrogen peroxide is poured into the chamber, until the steam pressure of hydrogen peroxide become 0.5-10Torr. The concentration of hydrogen peroxide to be poured into the chamber is about 0.05-10mg/L (chamber capacity). The products to be sterilized are held in the chamber for about 5-30min. during whose period power enough to sterilize them is generated. After this pre-treatment, the products receive the plasma either in the pre-treatment chamber or another plasma chamber. The RF energy to generate the plasma may be either continuous or pulsed. The products are held in this plasma for 5-60min. and hydrogen peroxide is decomposed into the nontoxic products during this treatment.

Fuel injection device for diesel engine

Abstract: PURPOSE:To prevent the occurrence of hunting of an engine by operating an electrostrictive actuator in the direction of finishing pilot injection when output voltage of a sensor reaches a reference voltage at the time of pilot injection CONSTITUTION:With the rotation of a pump driving shaft, a cam 8 is lifted so that pressure in a plunger chamber 3 increases and simultaneously output of a sensor 7 increases When it becomes above nozzle valve opening pressure, pilot injection is started Subsequently, the plunger chamber pressure continue increasing and the sensor output is compared with a reference voltage by a controller 6 When the output becomes equal to the reference voltage, a piezo element is short-circuited, and output of an electrostrictive actuator 1 suddenly becomes zero to discontinue injection In the above injection stroke including pilot injection, a reference voltage for deciding the short-circuit time of the piezo element is regarded in such a manner that during idling, at every time, peak values of sensor output are peak-held on every cylinder, and the average value of plural peak values up to the preceding time synchronized with each cylinder is divided at a designated ratio

Method of reducing self-burning oxde for sealing nitride deposition

Abstract: PURPOSE: To form a sealing layer of a silicon nitride without generating a new natural oxide by removing a natural silicon dioxide from a silicon substrate by HCl or H2 etching, and, continuously, introducing silicon nitride deposition gas, in a chamber at high temperature and reduced pressure. CONSTITUTION: A semiconductor substrate wafer 2 is charged in a crystal tube reaction furnace 1 with the use of a boat 3, and a heating coil 9 is regulated with a power source and a temperature controller 8. And a valve 18 is opened to make hydrogen chloride gas flow thereinto, keeping the chamber pressure at about 100mTorr, and about 800-900 deg.C, for complete removal of a natural silicon dioxide. Then, after a residue is discharged, ammonia and either dichlorosilane or silane are poured, and the chamber pressure of about 700mTorr is kept. Thereby a thin sealing silicon nitride layer of about 12nm is directly formed on a clean single crystal silicon substrate of the wafer 2.

Method and apparatus for vapor growth

Abstract: PURPOSE:To improve the surface quality by a method wherein, when the pressure in a reaction chamber which is evacuated is elevated to a growth pressure, by introducing leak gas into the chamber, it is passed through a transition pressure region from a molecule flow region to a biscous flow region at a specific pressure rise speed. CONSTITUTION:Substrates 1 are mounted on a barrel type susceptor and, after the susceptor is placed in a reaction chamber, the reaction chamber is evacuated so as to provide a high vacuum state of 10 -10 Torr. Leak gas the same as carrier gas such as hydrogen, nitrogen and helium is introduced into the reaction chamber by opening a leaking valve 10 and is passed through a transition pressure region from the high vacuum state of a molecular flow region to the growth pressure of a biscous flow region at a speed determined by an equation dP/dt=Po*a*t*10 , wherein P0 denotes the pressure of the initial evacuated state, P denotes the pressure in the growth chamber after (t) minutes and (a) denotes a constant conforming to the relations 0.5<=a<=2, to increase the chamber pressure to the growth pressure of about 0.5-100Torr. Then raw gas is introduced to carry out vapor growth. With this constitution, the deterioration of the surface quality can be suppressed.

Temperature sensitivity relationships for nonsteady processes

Abstract: Analytical relationships connecting “instantaneous” temperature sensitivities of chamber pressure for quasisteady and nonsteady (progressive) solid rocket motor burns are derived from a bulk mode, isothermal, ideal gas model and tested with numerical calculations from an exact, bulk mode model. Results show that (a) the instantaneous temperature sensitivity of progressive, nonsteady burns can be substantially reduced relative t o quasi-steady burns for identical initial states and temperature differences and (b) the analytical relationship’s predictions are within 7% of the exact results. Since this is within the expected accuracy of TK measurements, the connective relationships can be employed to either extract T K data from progressive, nonsteady motor burns or estimate the temperature sensitivity of these nonsteady processes. J

Advanced H2/O2 space engine parametrics

Abstract: Engine cycle analyses conducted on a 3000-lbf component testing model of an H2/O2-fueled advanced orbit-transfer vehicle engine employing a dual-expander cycle have yielded pressure and temperature trend predictions. On the basis of the results obtained, the dual-expander cycle is projected to be scalable to thrust levels of as much as 50,000 lbf, with chamber pressures of 2000 psi. The high chamber pressure, in conjunction with the use of a gas-gas injector element, facilitates 10:1-range continuously variable throttling. The preferred thrust level for supporting mission studies would be of the order of 20,000 lbf.