Abstract: Reduction or cancellation of acoustic noise is achieved by providing an amplified, oppositely phased version of the noise by means of an acousto-fluidic amplifier. The amplified acoustic output noise is delivered through an impedance matching horn in destructively interfering relation with the original noise. Depending on the acoustic noise source and its spatial distribution, the acousto-fluidic amplifier may be a single stage amplifier or multiple stages connected in parallel and/or cascade, with output horns spatially distributed to have the maximum cancellation effect. Sensed noise, prior to fluidic amplification, may be processed in a manner to effect feedback or feedforward control of the amplified acoustic output signals.

Abstract: The present invention relates to a temperature control valve having no mog parts. The temperature control valve has a fluid inlet and a fluid outlet. A fluidic amplifier communicates with the fluid inlet and is characterized by a first outlet port for distributing a flow of fluid to an external device such as a heat exchanger, a second outlet port in communication with the fluid outlet, and two control ports. A feedback loop is used to control the fluidic amplifier. The feedback loop has a first channel with a temperature sensitive element connected to one of the control ports and a second channel with a bias resistor for setting a desired output temperature for fluid flowing through the fluid outlet. The first and second channels create a pressure difference between the control ports of the fluidic amplifier corresponding to the desired outlet temperature.

Abstract: Turbulence is controlled in boundary layer or wall-bounded fluid flow fields having a turbulent wall region characterized by a system of roll pairs extending in the direction of flow, and obliquely propagating structures interacting with the system of roll pairs, by locally introducing into the turbulent wall region two separate disturbances that are effective to produce, in a local region, a composite disturbance field that is strongly coupled to and modifies the obliquely propagating structures in a manner that increases or decreases the interaction of the propagating structures with the system of roll pairs thereby locally increasing or decreasing the turbulence in the flow field. One of the disturbances may result from the interaction of the fluid with a linear strip, or an array of strips, of delta-shaped protrusions positioned spanwise on the wall (i.e., transverse to the flow direction); and the second disturbance may result from injecting sonic energy into the local region.

Abstract: A fluidic sound amplification system couples successive laminar proportional amplifiers through acoustic radiation between output and input horns to avoid the propagation of null offset signals. A second approach to obviating DC null bias in a fluidic sound amplification system comprises splitting the input signal, effecting a selected time delay on a portion of the signal such that the bandpass frequencies and dead zones or cancellation frequencies respectively of the amplified signals are 180.degree. out of phase and combine to produce a near uniform frequency response. A third approach is to use multiple parallel elements in each stage of amplification in such a manner that mechanical errors cancel each other out.

Abstract: An apparatus for dispensing a cryogenic liquid includes means for focusing a beam of energy, eg. laser energy from a source onto the liquid cryogen as it passes through an outlet from a cryogenic liquid container.

Abstract: The invention relates to an apparatus and method for regulating the flow rate of a liquid furnace product. The apparatus comprises a heat exchange jacket (10) surrounding a conduit (9) through which liquid furnace products flow. The heat exchange jacket (11) removes sufficient heat from the conduit and product flowing therein to cause a shell of solidified product to form on the internal surface of the conduit. The flow rate in the conduit is controlled by regulating the coolant flow through the heat exchange jacket and consequent shell thickness.

Abstract: The present invention is an apparatus for restricting the flow of fluid. The apparatus defines a tubular member having a channel. The tubular member has a first portion in which the channel has a first cross sectional area. There is also a second portion for restricting the flow of fluid defined by a reproducible deformity in the channel such that the channel has a second cross sectional area which is smaller than the first cross sectional area of the first portion. The tubular member further defines a third portion having a third cross sectional area which is greater than the second cross sectional area of the second portion. All of the cross sectional dimensions of the second and third portions are disposed within a cylindrical envelope having a diameter equal to the diameter of the first portion and extending therefrom. The tubular member is comprised of a material having sufficient rigidity to maintain a preferred reproducible permanent deformity in the channel.

Abstract: The invention relates to a method for producing a heatable and refrigerable element (12) for a system handling small amounts of liquid and to an element manufactured by the method. The element comprises flow channels (11) and one or more liquid spaces (8) communicating with them, the channels being provided with valves (10) connected to a refrigerator (25) and a heater (18), for blocking the channels by freezing the liquid in them. The element (12) is produced by using a removable mould which serves as a substrate for deposition and by depositing one or more metallic materials by electroformation or an equivalent procedure in such a way that the deposited metal forms a shell (5, 7) by removing the mould from inside the shell by dissolving or smelting, and by connecting the shell at the spot of the valves to a refrigerator (25) and a heater (18). The deposition is carried out so that there is a higher thermal conductivity at the spot of the valves (10) than in the adjacent shell areas.

Abstract: An apparatus for use in space environments to control the flow of a propellant to a thruster at a low mass flow rate comprises an insulated body having a cavity therein defining a vaporizing chamber, a porous medium having a low liquid permeability disposed in the chamber, a conduit means for feeding a propellant liquid into the chamber and exhausting a propellant vapor from the vaporizing chamber, and a heating means communicating with the medium within the chamber for controllable heating of the liquid propellant in the chamber creating a variable liquid/vapor transition zone within the medium. The transition zone is responsive to the heating means to control the mass flow rate of propellant through the vaporizing chamber. As the liquid/vapor transition zone is moved upstream by increasing the heater output, and thus increasing the volume of vapor within the porous medium, mass flow through the porous medium is decreased.

Abstract: An ejector for use in a refrigeration system has a mixing tube or diffuser which is partitioned into multiple flow passages. Selectively directing a continuously flowing primary high velocity fluid jet stream, which stream entrains a secondary fluid, cyclically into each of the multiple flow passages creates an effective pulsing of the primary high velocity fluid jet stream with respect to each flow passage. Pulsing the primary high velocity fluid jet stream in this manner enhances the mixing and compression of the primary high velocity fluid jet stream and the secondary fluid in the diffuser.

Abstract: A pneumatic actuator comprises a cell through which a normally laminar flow of air passes between an inlet and an outlet to provide, in the outlet, an output pressure. The cell includes an electro-acoustic transducer, for example a piezo-electric element arranged, in response to an oscillating electrical signal, to produce an acoustic signal that disturbs the laminar flow whereby at least some of the air exhausts from the cell via one or more exhaust ports and the output pressure falls. The difference in the output pressures may be used to control a pneumatic device optionally via a pneumatic amplifier. The electrical signal is produced by an opto-electrical transducer to which optical control signals are transmitted, for example along a fibre optic cable.

Abstract: Method of opening and closing a fluid passage comprises the steps of freezing fluid in the fluid passage by first cooling the fluid to a temperature below the freezing point of the fluid to close the fluid passage and after the fluid passage is closed, raising the temperature of the fluid close (or just below) to the freezing point of the fluid, whereby the fluid passage is maintained in a closed state with a small power supply and the responsiveness in opening the fluid passage is enhanced.

Abstract: Substantial alteration of the flow conditions in a fluid stream are effected by the application of controlled disturbances to the boundary of or within the stream by one or more piezoelectric actuators. The actuators have resonance frequencies substantially in excess of the unstable frequencies of the stream. The actuators are energized by carrier signals at the resonance frequencies of the actuators, which carrier signals have been modulated at the desired unstable frequency of the stream.

Abstract: The movement of particles in a liquid flowing in a duct is controlled by an ultrasonic standing wave having nodal fronts at a small angle to one pair of side walls of the duct. As the liquid flows along the duct, particles responsive to the acoustic energy are held on the oblique nodal fronts and are carried along these by the flow so that they also move towards one side wall. Particles in the vicinity of that one side wall are swept from the nodal fronts by the liquid drag forces. At the duct exit the particles will therefore tend to be concentrated in that portion of the liquid flow that passes nearer said one wall.

Abstract: An apparatus for controlling the opening and closing of a channel for a liquid is arranged such that a liquid channel is closed by causing a controller to control one heat absorbing and generating part of a cooling/heating element to execute heat absorption and cooling a heat transmitting element to solidify the liquid in the channel. The apparatus is also arrangement such that the channel is opened first by causing the controller to control the same heat absorbing and generating part to execute heat generation and heating the heat transmitting element to melt the liquid solidified in the channel. A method of controlling the opening and closing of a channel according to the invention includes the steps of: solidifying a liquid in a channel by cooling it from the outside to close the channel; and opening the channel thus closed by melting the liquid solidified in the channel by the application of heat.

Abstract: The present invention provides a method for transferring agglomerative short fibers such as natural fibers, ceramic fibers or metals, by means of a Coanda spiral flow produced by feeding a pressurized fluid. In this fluid-transfer, short fibers can be smoothly transferred with an orientation while causing swelling and dissociation of agglomerates thereof. The defects inevitable in the conventional transfer under turbulent flow conditions such as adherence of fibers to the inner wall of the pipe, agglomeration and breakage of whiskers are completely solved. High-speed oriented-transfer at a speed of several to 100 m/second is possible by means of the Coanda spiral flow.

Abstract: A gas valve which is particularly useful in a laser gas fill system requiring repeated fillings includes a conduit positioned between high and low pressure gas regions. Within the conduit is a restriction, and this restriction is closed by a meltable solid material. When the valve is to be opened, heat is applied to the meltable solid material, either internally or externally, causing at least some of the material to flow and allow the passage of gas from the higher pressure region to the lower pressure region. When the pressure between the two regions has substantially equalized, or at least the pressure differential has greatly diminished, surface tension associated with the restriction in the conduit pulls the liquified material back into place to close and reseal the valve, at which point heat application is dicontinued so that the material again becomes solid.

Abstract: An enhanced output opto-fluidic device includes three plates which together bound a number of passages including an interaction passage, an inlet channel including which opens into one of such ends, and two outlet channels which open into the other end of the interaction passage at symmetrically arranged outlet regions. Fluid is caused to flow through the inlet channel into the interaction passage to form a jet stream that flows toward the outlet regions.

Abstract: In variable air volume systems of buildings, a vortex valve is used for varying the volume of the air moving through the system.

Abstract: The invention concerns a procedure for forming cocks closable by freezing, belonging to a liquid batch handling unit, and a liquid handling unit set up in accordance with the procedure. The unit consists of two bodies (1,2) placed against each other, the cocks being located between their faces and one of them (2) comprising the flow passages leading to the cock points and the other body (1), which is connected to a refrigerator, being provided with electric heaters located at the cock points and with the aid of which the cocks can be opened and closed.

Abstract: A focused optical input signal is applied to an optically absorbent wall portion of one of two convergent supply nozzles in a fluidic device to reduce the thickness of the flow boundary layer. The boundary layer reduction deflects the combined nozzle discharge to achieve a desired output from the device.

Abstract: In a method for electromagnetically regulating flow and in an apparatus for performing the method, a molten metal flowing in a pouring tube is inhibited in a central region of the pouring tube by an insert member installed in a conduit of the pouring tube and is diverted radially outward. An electromagnetic coil is arranged concentrically about the pouring tube for exerting constrictive electromagnetic forces upon the molten metal and thus regulating the flow of molten metal in a wide range.

Abstract: An arrangement for the remote actuation of a controlled device, e.g. a hydraulic valve, in situations with stringent safety requirements, uses optical power. The optical power, e.g. from a high-power laser, is conveyed via an optical fibre (1) to the controlled device. Here it falls on a heat-absorbent surface (2), as a result of which a volatile fluid (e.g. freon) is evaporated. This via a bellows (4) drives an output rod (5), which operates the controlled device.Alternatives include a bimetallic strip, a thermostat-type capsule, and a memory metal strip, as the heat responsive device.

Abstract: A flame failure device for a gas-fired appliance has a heat sensitive device (24') in the form of fine bore tube (25). The tube is connected to one chamber (10) of a pressure sensitive gas flow control valve assembly. The chamber is pressurized and the rate of flow from the chamber is controlled by flow through the fine bore tube (25) the application of heat to which reduces the rate of flow through the fine bore tube (25) while the withdrawal of heat restores the rate of flow. Heat is provided by a gas burner of the appliance. The fine bore tube may have a non-circular cross-section and be formed by deforming part at least of a length of tubing (FIGS. 4A and 5B).

Abstract: A valveless gas shut-off and transfer device has a looped conduit with a solder-like material in the loop. This eutectic material solidifies below its critical temperature to block the conduit and is liquefied above its critical temperature to allow passage of gas through the conduit. Baffles on the outlet retain the liquefied solder when gas is passing through the device. The liquid solder flows back to the loop when pressures at the inlet and outlet are equalized. When the solder solidifies, the device is again blocked.

Abstract: A focused optical input signal is applied to an optically absorbent wall portion of a supply nozzle 40 in a fluidic device to cause boundary layer separation of flow therein. The boundary layer separation turns the flow to achieve a desired output from the device.

Abstract: An unfocused optical input signal is applied to an optically absorbent wall portion of an interaction region 30 in a fluidic device to effect flow impedance modulation thereat. The flow impedance modulation adjusts the velocity profile of the flow to achieve a desired output from the device.

Abstract: A pulse width modulated pressure source wherein the path between a fixed pressure source and an output receiving port is interrupted periodically so that the receiving port receives a modulated pressure of a controlled value less than the predetermined pressure source.

Abstract: A photofluidic interface that transduces optical control signals into fluid ontrol pressures is provided in which an AC modulated light source is utilized to transmit control signals to a photo acoustic cell that absorbs the light energy and converts it to heat energy thus creating pressure pulses within the cell. The output signal of the photo acoustic cell is then fluidically amplified, fluidically rectified and again fluidically amplified to create an output signal that drives an actuator.

Abstract: An ink jet system using a single transducer chamber is disclosed which can produce a wide variation in visual print density (gray scale) without a reduction in print resolution. Vehicle is mixed with the ink during the actual jet printing process to produce the desired gray scale. The system is also readily adapted to produce multi-color prints.

Abstract: A new method and apparatus for fluid sound amplification and detection having enclosed within a predetermined sized housing a fluid supply emitter in combination with a signal input port and spaced a predetermined distance therefrom along an axis offset a determined distance from the fluid supply emitter axis, at least one receiver, the receiver being responsive to gradient differences in fluid pressure as effected by laminar flow of the fluid from the emitter, a filter connected to the receiver for removing relatively high frequency noise, a diaphragm coupler receiving the output of the filter, the coupler having an output for use as a signal input to another predetermined sized housing, emitter, signal input port and at least one receiver combination. A suitable input transducer is connected to the signal input port of the first housing combination and a suitable output transducer such as a recording microphone and oscilloscope is connected to a receiver output of the second housing combination.

Abstract: An apparatus for stopping the fluid flow through a pipe by freezing the fluid. The apparatus is for use especially in oil wells, gas wells, and the like. A head of arcuate shape has inwardly radially extending fingers whose purpose is to locate the pipe in the center of the head. The head is securely attached to a bar for supporting and transporting the entire device. The head has attached thereto a supply tube with jets radially extending from the supply tube toward the pipe. The jets supply a pressurized refrigerant about the periphery of the pipe, this refrigerant lowers the temperature of the pipe sufficiently to freeze the contents and thus stops the flow within the pipe.

Abstract: A switch arrangement in which shock wave energy is utilized to switch the path of a fluid through a fluidic device, the switch arrangement being such that a reflector is employed to direct the shock wave to a desired position in the switch arrangement.

Abstract: A device for simultaneously modulating and amplifying low frequency sounds which comprises a tubular member having an axial bore extending a distance interiorly of the inlet end thereof and tapering to a reduced axial bore in said tubular member. A generally perpendicular passageway in said tubular member intersects said reduced axial bore, the top wall of which terminates adjacent to said intersection and the bottom wall of which extends past said intersection, said extended portion being deflected a finite angle relative to the normal axial flow. The tubular member is received by a sleeve, and a first baffle flared in the direction of the flow is angularly disposed relative to said sleeve to define a first passageway in said tubular member.

Abstract: A fluidic throttling flow controller for controlling core cooling flow in a uclear reactor. Increased temperature of cooling flow adajcent the core increases the flow adjacent the core and is used to control a focused jet amplifier which in turn controls a vortex valve to reduce flow and shut down the reactor when overheating occurs.

Abstract: A system for controlling pressure in a container, for example the carburetor of an internal combustion engine, from a periodic acoustic source, for example the intake or exhuast of the engine or a selected engine component where the alternating pressure varies only slightly according to engine speed where it is desired to modify the slope of a fuel richness curve over a wide operating range. The system is characterized in that it comprises a conduit connecting the container chamber to the acoustic source, the pressure losses being different according to the direction of flow in the conduit.

Abstract: A device for simultaneously modulating and amplifying low frequency sounds which comprises a tubular member having an axial bore extending a distance interiorly of the inlet end thereof and tapering to a reduced axial bore in said tubular member. A generally perpendicular passageway in said tubular member intersects said reduced axial bore, the top wall of which terminates adjacent to said intersection and the bottom wall of which extends past said intersection, said extended portion being deflected a finite angle relative to the normal axial flow. The tubular member is received by a sleeve, and a first baffle flared in the direction of the flow is angularly disposed relative to said sleeve to define a first passageway in said tubular member.

Abstract: A resistive element for a fluidic system having a load and a supply of wong fluid at a supply pressure which is a constant independent of temperature. The resistive element comprises a housing, of a relatively low temperature coefficient of expansion material such as a steel, enclosing a pair of coplanar plates of predetermined dimensions and fabricated from a relatively high temperature coefficient of expansion material, such as a magnesium alloy. The adjacent walls of the plates define the sidewalls of a channel for fluid flow. The plates are slidably mounted inside the housing so as to vary the width of the rectangular channel at a constant rate in response to incremental variations in the fluid temperature. The constant variation in channel width keeps the Reynolds number of the fluid passing through the channel at a substantially constant value despite small increments in the fluid temperature about its operating temperature.

Abstract: A fluidic system (e.g. amplifier or bistable unit) having an inlet branch and a pair of outlet branches separated by a fluid-flow splitter whereby the fluid is rendered electromagnetically susceptible, e.g. magnetic by incorporating magnetic particles therein, electrostatically responsive by being relatively dielectric, or electrically conductive, so that the fluid flow to the outlet branches may be controlled by magnetic, electrostatic or current flow means or an output may be derived by similar electromagnetic means for controlling an ancillary device, providing an indication of a fluid flow parameter or feedback control of an input parameter.