Showing papers on "Internal pressure published in 1985"

Initiation of localized plane deformations at a circular cavity in an infinite compressible nonlinearly elastic medium

Abstract: This investigation is concerned with the plane strain deformation of an infinite slab, containing a circular cavity, within the theory of finite elastostatics for a particular homogeneous isotropic compressible material, the so-called Blatz-Ko material. The body is subjected to uniform pressure, either internal or external. Exact closed-form solutions for the axisymmetric deformation and stress fields are obtained. In the case of internal pressure, it is found that the applied pressure may not exceed a certain maximum value pmax. At a value of pressure pe (

Constant pressure tourniquet

Abstract: A constant pressure tourniquet has an interior chamber formed therein by a continuous wall surface. The wall of the tourniquet is made of an expansible elastomeric material. The chamber is inflated with a suitable fluid to a pressure in excess of the threshold pressure provided by the elastomeric material. The tourniquet preferably is of annular or rectangular configuration, and can be adjustably arranged to effectively form a toroidal void within which a pressure producing fluid is contained. The tourniquet is made in various different sizes and configurations, and includes overlapping marginal ends which are fastened together and thereby provides a suitable inside diameter for proper placement about one's limb, such as a finger, arm, or leg, for example. The physical characteristics exhibited by the elastomer are selected to provide the required internal pressure for preventing bleeding. The internal pressure and size of the tourniquet therefore is selected to prevent bleeding of that part of the anatomy that receives the tourniquet.

Snow-disposal unit and method

Abstract: A mobile snow-disposal unit having a vehicle including a sealable snow-collection receptacle having a water-holding internal compartment and an engine for propelling the vehicle utilizes a vacuum pump for lowering the internal pressure of the receptacle, when sealed, and a heat exchange system for routing waste heat from the engine to the internal compartment. By lowering the internal pressure of the receptacle so that the boiling temperature of water held by the internal compartment is about equal to the temperature of the waste heat entering the internal compartment, water held within the internal compartment is converted to steam for readily melting the collected snow.

Experimental Stress Analysis of Four Fabricated Equal Diameter Branch Pipe Intersections Subjected to Moment Loadings and the Implications on Branch Junction Design

Abstract: Four 250 mm (10 inch) equal diameter branch junctions of different thickness have been subjected to all six external moment loadings that can occur in practice, together with internal pressure in one case. The results of detailed experimental stress analyses are presented and are discussed in the light of current American and British piping design codes.

Williams' blister test analyzed as an interface crack problem

Abstract: A model is constructed to analyze more carefully the energy release rate for Williams' blister test. The model, which consists of an interface crack between two elastic layers, is loaded by uniform internal pressure. The singular integral equations for the dislocation densities are derived and solved using numerical quadrature and the energy release rate is calculated directly from the dislocation densities. Both the two-dimensional and axisymmetric penny-shaped crack problems are considered, and it is noted that there are significant differences between these two cases. It is found that in some cases crack propagation will not be catastrophic.

Air pressure controlling device of die cushion

Abstract: PURPOSE:To control tank pressure to set pressure in a short time by comparing set pressure set to a digital switch with tank pressure of a pressure sensor connected to an air tank and correcting this by anticipated amount of delay of an air controlling system. CONSTITUTION:The pressure sensor 10 generates voltage corresponding to secondary pressure, and the analog signal is inputted to an A/D converter 11 and converted to a digital signal. The digital signal is inputted to a corrector 12 and corrected from change of ambient temperature, working power source voltage etc., and the signal corrected to correct value is sent to an arithmetic unit 13. A digital switch 14 sets internal pressure of a die cushion cylinder 1 necessary for press work, i.e. secondary pressure of an air tank 2, and outputs a digital signal corresponding to the set pressure and sends to the arithmetic unit 13. The arithmetic unit 13 compares it with a signal from the corrector 12 and operates, and outputs a signal to a solenoid valve 9 for pressure adjusting to make necessary operation.

Buckling of glass-reinforced plastic cylindrical shells under combined axial compression and external pressure

Abstract: The paper describes the results of a theoretical and experimental investigation into the buckling behavior of glass-reinforced plastic cylindrical shells under the action of combined axial load and internal pressure. A total of 20 shells were loaded to buckling. Initial imperfections, load-deflection response, and buckling modes and loads were determined experimentally and compared with the results of a finite element analysis. This analysis utilized a buckling criterion developed on the basis of the total potential energy. The proposed method of buckling load prediction is shown to give close agreement with the experimental results.

On the Characteristics of Bolted Joints with Gaskets : stress analysis of full face metallic flat gaskets interposed between pipe flanges

Abstract: This paper deals with a contact stress distribution in bolted joints when a full face metallic flat gasket is interposed between two pipe flanges. Replacing a gasket and pipe flanges by finite hollow cylinders the contact stress distribution is analyzed using three-dimensional theory of elasticity. By numerical computations, effects of the thickness and the stiffness of gaskets on the contact stress distribution are shown. Next, the force ratio of bolted joints with gaskets, which is the ratio of an increment of bolt axial force to an internal pressure and the sealing performance are analyzed. With an application of the internal pressure, a bending moment is produced in bolts. The maximum stress produced in bolts taking this bending moment into consideration is also analyzed. For verification, experiments are performed. Analytical results are in a fairly good agreement with experimental one.

The Influence of Grain Pressure on the Buckling Load of Thin Walled Bins

Abstract: THE buckling stresses of model grain bins with varying radius to wall thickness (r/t) ratios and levels of internal pressure were determined. No available analytical model effectively predicted the observed results. A best fit model with lower bounds is presented that relates the buckling stress to the level of lateral grain pressure and the r/t ratio of the bin wall.

Hollow body which is subjected to internal pressure stresses and/or temperature stresses

Abstract: A hollow body which is subjected to internal pressure stresses and/or temperature stresses is produced from material having a low tensile strength, its outer surface being constructed to be concave in a multiple manner Its depressions run longitudinally or at right angles to its longitudinal direction or as required, in any desired directions At least the points of the projections on the outer surface can be held by a material having a higher tensile strength In consequence, cheaper materials can be used, or expensive materials can be utilised better Good heat insulation and good heat conduction are possible so that the hollow body according to the invention can be used advantageously for heat or cold transportation lines, ceramic motors, pressure reactors, furnaces, heat exchangers, solid-object transportation lines where a large amount of frictional heat is developed, machine shaft bearings or similar applications

Method and apparatus for manufacturing high-density carbonaceous material

Abstract: PURPOSE:To obtain the titled carbonaceous material which is isotropic and large-sized and has excellent strength and resistance to corrosion by inserting a specified capsule wherein a carbonaceous molded body is enclosed into a high-pressure vessel, controlling the external pressure of the capsule to the pressure higher than the internal pressure, and calcining. CONSTITUTION:A molded body 13 consisting of a mixture of a carbonaceous filler material such as carbon fiber and an organic material binder such as tar pitch are melted and enclosed in a metallic H2-permeable or H2-occlusive capsule 12 equipped with an atmosphere regulating tube 14 wherein a hardly sintering ceramic powder 14' is packed so that the gas may be passed through. The capsule is inserted into a high- pressure vessel 1, and heated with heating bodies 4 and 4'. While the indicated values of pressure gauges 19 and 20 which are provided to a pressure medium gas and the pressure system in the capsule are compared, the pressure is increased through a pressure medium gas introducing hole 8 by operating a compressor 18 when the internal pressure of the capsule is increased due to the generation of decomposed gases resulting from calcination. Or the pressure is lowered by opening a valve 22 and releasing the internal pressure to control the pressure of the pressure medium gas to the pressure higher than the internal pressure of the capsule.

Pile penetration work

Abstract: PURPOSE:To prevent the settlement of a box into the ground by a method in which a bottom-opened box is placed on the ground, the inside of the box is evacuated to reduced pressures to obtain penetrating reaction of a pile while adjusting the internal pressure of the box by measuring the tension of a penetrating rope. CONSTITUTION:A bottom-opened box 4 is placed on the ground and the air in the box is discharged through an air outlet 5 by means of a vacuum pump 6, whereupon the box 4 is pressed into the ground by the atomospheric pressure. When a rope 15 is rolled up, the length of a main rope 15 of 12 turns, engaged between 8 upper pressing sheaves 10 and 8 lower sheaves 11, is contracted, the force for the box 4 acts on a coping 2, and the pile 1 is pressed downwards. This case, the tension of the rope 15 is measured by a sheave 22 for measurement, an oil-pressure cylinder 21, and a pressure guage 23 provided on the upper part of the box 4. The regulating valve 19 is adjusted by a vacuum meter 20 and air is introduced into the box 4 to keep the internal pressure proper in order to prevent the settlement of the box 4 into the ground.

Correlation of surface tension with bulk properties for molten alkali halides

Abstract: The surface tension of alkali halide melts has been correlated with the bulk modulus and with the internal pressure. These are similar to those found earlier for liquid metals. The relationships, along with the volume expansion coefficients, can be used to calculate the temperature coefficient of surface tension.

Control on injection process of injecting molding machine

Abstract: PURPOSE:To obtain a highly accurate molding free of a stress by a method in which a brake device is actuated at the same time switching is made to a pressure maintainer process, and the blade device is locked by the detection of the positions of a screw or a plunger or of the internal pressure of the mold cacity. CONSTITUTION:In injecting a molten resin into the mold cavity 13, a screw 16 is advanced for high-speed packing. When the pressure of molten resin injected is detected by a pressure sensor 18 and the internal pressure of the cavity 13 reaches a set value by a pressure setter 26, a relay R1 is operated. Return oil from a cushion chamber is backed to a tank, the contact-A is connected to R1, and thereby the amount of oil to an injection cylinder 19 is controlled on a set value by a flow rate setter 30 by means of an electromagnetic flow cone 25. When the internal pressure of the cavity 13 coincides with a set value by a pressure setter 27, a relay R2 is operated, an electromagnetic switch valve 24 is set to neutral position, and return oil from the cylinder 19 is blocked. The flow cone 25 is controlled by signals from an arithmetic unit 33b to keep the stop position of the screw 16.

Method of supplying fuel to engine

Abstract: PURPOSE:To prevent vapor from being generated, by feeding air pressurized by an air pump into a fuel tank to raise the internal pressure of the tank so that fuel is transferred under air pressure. CONSTITUTION:Upon operation of an engine 1 and air pump is driven to feed pressurized air into a fuel tank 5 so that the internal pressure of the tank 5 is increased to pressurize fuel which is therefore transferred under pressure through a fuel passage 6 to a constant fuel level chamber in a carburettor 3. With this arrangement the fuel system from the fuel tank 5 to the intake-air passage has no fuel pump inlet side which produces vacuum, thereby it may be made difficult to generate vapor even high temperature operation.

Misfire detector for engine

Abstract: PURPOSE: To detect the state of an misfire quickly and accurately with a simple construction, by using a decision circuit to determine the condition under which the cylinder internal pressure at the position ahead of upper dead point in the compression by a specified crank angle and that at the position behind it by the same angle therefrom are almost equal CONSTITUTION: A specified crank angle α 1 corresponding to a through hole 13 on a disc 15 and a specified angle α 2 corresponding to a through hole 14 are set at the positions a specified angle β ahead of the dead point in compression and the same angle behind it respectively Especially, when the crank angle α 2 is set near the crank angle at which the peak β of the combustion pressure is generated, the cylinder internal pressure is detected at the peak βof the combustion pressure as cylinder internal pressure P 2 With such an arrangement, when the crank angles α 1 and α 2 are detected, a decision circuit 20 compares the internal pressures P 1 and P 2 and the same control is repeated until the P 1 and P 2 are almost equal Thus, when the internal pressures P 1 and P 2 are found to be almost equal, the circuit 20 judges that the state of misfire exists COPYRIGHT: (C)1987,JPO&Japio

Watch provided with atmospheric pressure measuring function

Abstract: PURPOSE:To obtain a watch having an atmospheric pressure data display system such that a user easily estimates the change of the weather, by succeedingly measuring atmospheric pressure by providing a clock circuit and a pressure-sensitive sensor circuit. CONSTITUTION:Because pressure to be measured acts on the surface of a substrate 1 while almost constant pressure in a hermetically closed container acts on the other surface thereof, a second substrate 4 is elastically deformed by pressure variation, for example, as shown by a two-dot broken line 4' and the gap between electrodes 2a, 5a, therefore, capacity therebetween changes. In this case, both substrates are constituted of an insulating material. At this time, only a central part may be etched so as to leave a mesa shape in order not to increase floating capacity. Further, in order to enable the measurement of pressure of a conductive liquid, wet gas or corrosive gas, the inner surfaces of the substrates 1, 4 are pref. coated by a proper insulating material. The internal pressure of the hermetically closed container is desirably brought to vaccuum if the change in a temp. due to the thermal expansion of an internal fluid is unfavorable, but, on the contrary, the temp. compensation of a detection circuit can be also performed by utilizing thermal expansion.

Hot air circulation type baking furnace

Abstract: PURPOSE:To maintain an internal pressure of a furnace by providing an exhaust pipe at the upstream position of a circulating fan and by adjusting automatically the discharged amount of hot air by the temperature difference of the hot air the upstream and downstream in an inlet or outlet of a treating material. CONSTITUTION:An exhaust pipe 9 is connected at the upstream position from a circulating fan 8 in the circulation path of hot air and an exhaust fan 10 is provided to the pipe 9. A catalyst layer 11, an introducing pipe 12 of the outside air and a burner 13 are provided at the upstream position further from the connection port of said pipe 9, and the temperture difference at the upstream and downstream of an inlet 3 or an outlet 4 of a treating material is detected and the discharged amount of the hot air from said pipe 9 is adjusted so as to maintain the temperature difference to a prescribed value. Therefore, the internal pressure of the furnace is maintained and the energy consumption is economized.

Method of detecting clogging in pulverized material gas-stream conveyor device

Abstract: PURPOSE:To rapidly detect the presence and position of clogging, by detecting the supply source pressure of conveying gas, the inside pressure of a pulverized material reservoir, the pressure of a gas-stream conveyor pipe and the inside pressure of a pulverized material consumption reservoir so that the position of clogging is detected in view of differential pressures among the above-mentioned detected pressures. CONSTITUTION:In a gas-stream conveyor system for conveying pulverized materials stored under pressure in a bin 1 to a blast furnance 2, a plurality of take-out ports 21, in the number corresponding to the number of tuyeres 22 in the blast furnance 2, are formed in the bottom surface of the bin 1, and discharge gas pipe lines L1 which are connected independently from each other, are directed to the respective take-out ports 21. Discharge pipes L2 connected respectively to the take-out ports 21 are connected through mixing-tees 20 to conveyor pipes L3. Further, there are provided a bin internal pressure gage 9, a conveying gas source pressure gage 11, conveyer gas pipe line pressure gages 13 through 17, a blast furnance internal pressure gape 18, etc. Detected pressures by the pressure gages 13 through 17 are monitored by, for example, a computer 19 so that the presence and position of clogging by the pulverized materials may be determined in view of variations in the balance of pressures detected by the pressure gages.

Non-compliant pressure cell

Abstract: The present invention is a pressure sensing and measurement device that eliminates errors due to compliance and lack of sensitivity. The cell uses a pressure receiving means (such as a flexible diaphragm) to detect an impinging object, a means to counteract the pressure caused by the impinging object (such as internal hydraulic pressure), and a detector to measure the amount of internal pressure used to counteract the impinging force. Since the cell is internally pressurized to a point equal to a value equal to the external pressure, the diaphragm is undeflected and may avoid the problems inherent in simple diaphragm systems (such as bridging and insensitivity).

Pipe length to which high pressure can be applied and which has a pressure measuring point

Abstract: The present invention relates to a pipe length having a pressure measuring point, in particular for pressures of between 100 and 1000 bar and media which can attack or encrust the inner wall of the pipe length. It is proposed to provide a pipe length with an inner wall (1) which serves as a seal and as a wearing part and is made from an elastic material. The inner wall (1) is surrounded on a segment by a metallic cylindrical ring (10) whose wall strength is dimensioned such that said ring is elastically deformed when the internal pressure to be measured is applied to the pipe length. The cylindrical ring (10) has one or more measuring devices (15, 16) preferably strain gauges, for measuring its deformation. The inner wall (1) or cylindrical ring (10) with measuring devices (15, 16) are surrounded by a housing (4, 7, 12) which absorbs all external forces and, apart from in the region of the cylindrical ring (10), the internal pressure, but does not prevent the expansions of the cylindrical ring (10). The pipe length is provided at both ends with connecting flanges (5, 8).