WO1997047013A1 - Rheostat a micro-gaz - Google Patents

Rheostat a micro-gaz Download PDF

Info

Publication number
WO1997047013A1
WO1997047013A1 PCT/US1997/009962 US9709962W WO9747013A1 WO 1997047013 A1 WO1997047013 A1 WO 1997047013A1 US 9709962 W US9709962 W US 9709962W WO 9747013 A1 WO9747013 A1 WO 9747013A1
Authority
WO
WIPO (PCT)
Prior art keywords
gas
rheostat
flow
housing
channel
Prior art date
Application number
PCT/US1997/009962
Other languages
English (en)
Other versions
WO1997047013A9 (fr
Inventor
Robert H. Reinicke
Stephen D. Bruneau
Original Assignee
Marotta Scientific Controls, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Marotta Scientific Controls, Inc. filed Critical Marotta Scientific Controls, Inc.
Priority to EP97929874A priority Critical patent/EP1008146A1/fr
Priority to JP10500913A priority patent/JP2000512780A/ja
Publication of WO1997047013A1 publication Critical patent/WO1997047013A1/fr
Publication of WO1997047013A9 publication Critical patent/WO1997047013A9/fr

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64GCOSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
    • B64G1/00Cosmonautic vehicles
    • B64G1/22Parts of, or equipment specially adapted for fitting in or to, cosmonautic vehicles
    • B64G1/24Guiding or controlling apparatus, e.g. for attitude control
    • B64G1/26Guiding or controlling apparatus, e.g. for attitude control using jets
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64GCOSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
    • B64G1/00Cosmonautic vehicles
    • B64G1/22Parts of, or equipment specially adapted for fitting in or to, cosmonautic vehicles
    • B64G1/40Arrangements or adaptations of propulsion systems
    • B64G1/402Propellant tanks; Feeding propellants
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02KJET-PROPULSION PLANTS
    • F02K9/00Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof
    • F02K9/80Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof characterised by thrust or thrust vector control
    • F02K9/805Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof characterised by thrust or thrust vector control servo-mechanisms or control devices therefor
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15CFLUID-CIRCUIT ELEMENTS PREDOMINANTLY USED FOR COMPUTING OR CONTROL PURPOSES
    • F15C5/00Manufacture of fluid circuit elements; Manufacture of assemblages of such elements integrated circuits
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64GCOSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
    • B64G1/00Cosmonautic vehicles
    • B64G1/22Parts of, or equipment specially adapted for fitting in or to, cosmonautic vehicles
    • B64G1/40Arrangements or adaptations of propulsion systems
    • B64G1/401Liquid propellant rocket engines
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05DINDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2250/00Geometry
    • F05D2250/80Size or power range of the machines
    • F05D2250/82Micromachines
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05DINDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2250/00Geometry
    • F05D2250/80Size or power range of the machines
    • F05D2250/84Nanomachines

Definitions

  • the invention relates to a variable control device for use in regulating or throttling of relatively low flows of fluid, the device being a solid state device capable of electronically regulating relatively low flows throughout a moderate flow regime.
  • pressurized gas such as Xenon
  • Xenon pressurized gas
  • a so-called "thermothrottle” a device of Russian origin
  • an elongate tube establishes a path for the requisite gas flow
  • an electrical heater winding developed around and along the length of the tube is the means of controlling gas temperature and viscosity, and therefore flow rate, between inlet and outlet ends of the tube.
  • U.S Patents 4,604,090 and 4,715,852 to provide a miniature device for automated metering of insulin to certain diabetic patients.
  • the device is surgically implanted in the body and establishes an elongate capillary path for controlled small flows of insulin within the body.
  • the device is a consolidated prismatic assembly of laminations, of microchip proportions, wherein a flat silicon chip has a photo ⁇ etched surface characterized by an elongate single capillary groove, which may have a length of 10 to 15 inches, helically developed on a square of approximately h inch flat surface, between inlet and outlet ends, with a glass plate bonded to the grooved surface to complete the integrity of a single flow passage in the groove.
  • the ambient environmental temperature is, of course, body heat, and there is no need for or suggestion of heat as a flow-control parameter.
  • the fluid is a liquid and in the environment of these patents the device and/or the patient is intolerable of the presence of a gas in the liquid.
  • the device provides a turndown of about 3:1 and has an average mass-flow rate of about 5 g/sec of gas, preferably Xenon; for example, a mass throughput ranging controllably from about 2 to about 6 mg/second.
  • the invention provides what may be termed as a micro gas rheostat for electrical- heater control of gas flow, comprising a consolidated body of flat laminations, wherein a first lamination has a grooved surface establishing a single elongate path between inlet and outlet ends of the path.
  • a second lamination has a flat surface bonded to the grooved surface of the first lamination, thereby closing the groove along its length to complete the exclusivity of communicating gas flow between the inlet and outlet ends.
  • the first lamination has a second flat surface in spaced parallel relation to the first surface, and an electrical- resistance heater element is bonded to, deposited on, or otherwise in heat-transfer relation with the second surface of the first lamination.
  • the electrical-resistance heater element is formed along a wall surface of the groove.
  • Elongate length of the groove is the product of a helical development between a central port and an outer port at the respective ends of the groove, and the inlet and outlet ends of the passage may be reversibly associated with the respective central and outer ports.
  • the helical development is a progression of square-leg sections, on a body of square or rectangular planform.
  • the inlet and/or outlet ports or both of them are associated with a so-called comb-filter array of groove formations in the grooved surface of the first lamination, the comb-filter grooves being of individual section area smaller than the section area of the flow-passage groove, but of collective section area exceeding the section area of the flow-passage groove, so that heater control of flow may be essentially limited to the helically developed flow passage.
  • the first, lamination is suitably a silicon chip, which is preferably of so-called single-crystal silicon, so that in utilizing photo-etching techniques to form the grooves, the grooves will be of V-section, in that etching will track the crystal-face orientation and will terminate at a depth at which the sides of the V intersect; thus, etched- groove width determines groove depth, and the narrower grooves for filter-comb formations will necessarily be of lesser depth (and section) than the wider grooves of the flow-controlled helical passage.
  • the fabrication of micromechanical devices relies upon techniques which the present invention employs; and these techniques have existed and been improved upon for more than the last decade. See, e.g. , James B.
  • the invention can employ any single-crystal material that can be processed as silicon can be processed in accordance with this invention, and which has sufficient mechanical and structural integrity to function in the environment in which the invention is desired to be used.
  • Such materials can include, for example, gallium arsenide, various silicate, borosilicate, alumino ⁇ ilicate, and related glasses, and various nitrides, such as boron nitride and silicon nitride.
  • the second flat lamination is suitably of borosilicate glass having substantially the same thermal coefficient of expansion as that of the single-crystal silicon of the first flat lamination.
  • This relation of expansion coefficients makes possible the consolidation of these laminations in an "anodic bonding" process as described in the literature; for example, George Wallis, “Field Assisted Glass Sealing", Electrocomponent Science and Technology, vol. 2, no. 1, pp. 45-53 (1975) and “Field Assisted Glass-Metal Sealing", infra, (the disclosures of which are incorporated herein by reference) .
  • inlet and outlet port connections to the respective ends of the grooved passage, via one or more comb-filter arrays are made via the thickness of either one of the bonded laminations; alternatively, the comb- filter formations and inlet/outlet connection thereto may be external to the device and may be external to the bonded laminations but nevertheless communicating with one or both of the respective ends of the helical groove path.
  • Silicon wafers are commercially available for today's micro-electronic purposes and are well-adapted to the kind of photoetching procedures outlined above in the Angell and Petersen articles (incorporated hereinabove by reference) .
  • a standard wafer of 3-inch diameter and 0.015-inch thickness can serve for the simultaneous photo- etched reproduction of an array of 37 duplicate silicon- lamination area elements (0.375 x 0.375 inches square) .
  • Known techniques such as diamond saws and laser beams, are available for cutting individual etched elements away from each other, it being preferred that the glass lamination shall have been bonded to the etched array prior to severing into individual but identical assemblies. And it is observed that for certain applications there is merit in retaining an integrally assembled plurality of the elements as a compact, unsevered, multiple-element array.
  • the rheostat is a multilayer body that is structurally isolated from the housing but attached thereto by having been bonded to a metal foil disposed securely within the housing.
  • the securement of the chip to a foil layer acts to isolate the body from mechanical and/or thermal stresses induced in the housing, from being transferred to the chip; such stresses can degrade the functioning of the chip and may - be great enough to crack, distort, or break the chip.
  • Etched onto a surface of the body are a series of connected flow channels, preferably including a series of filters, and also preferably having a serpentine or extended configuration along the surface in order to allow heating of the body to reduce the mass flow through the channels. The body is heated by passing a current directly therethrough, such that the body itself becomes a resistance heater.
  • this invention provides a solid- state device for throttling mass flow in a moderate flow range, such as a turndown ratio of about 3:1.
  • Fig. 1 is an enlarged view in vertical section for a complete micro-gas rheostat device of the invention
  • Fig. IA is a bottom-end view of the device of Fig. 1;
  • Fig. 2 is a top-end view of the device of Fig. 1;
  • Fig. 3 is a greatly enlarged plan view of a groove surface of a lamination in the device of Fig. 1;
  • Fig. 4 is a side view of the device of Fig. 1, to the scale of Fig. 3, and partly broken-away and in section at a mid-section plane;
  • Fig. 5 is a schematic representation of a heater element, forming part of the device of Fig. 1 and to the scale of Fig. 3;
  • Fig. 6 is a greatly enlarged fragmentary section illustrative of one of the grooves in Fig. 3;
  • Fig. 7 is another fragmentary section illustrative of other grooves in Fig. 3 and to the scale of Fig. 6;
  • Fig. 8 is a greatly enlarged fragmentary detail, in plan view of a corner of the grooved plan of Fig. 3;
  • Fig. 9 is a view of a conventional circular silicon wafer-, suitable for multiple photo-etched reproduction of the grooved plan of Fig. 3;
  • Fig. 10 is a graphical display of mass-flow rate turn-down ratio as a function of Xenon-gas temperature, for several illustrative starting or reference temperature situations commencing at unity turn-down ratio for each of these situations and covering the range to 600 F;
  • Fig. 11 is an idealized cross-sectional view of a rheostat device according to the invention, and Fig. 12 is a top view thereof; and Fig. 13 is a cross-section thereof taken along line 13-13 in Fig. 12; Fig. 14 is an idealized top view of the flow-control layer of the microrheostat, and Fig. 15 is a cross-section along line 15-15 of Fig. 14;
  • Fig. 16 is a graph of viscosity versus temperature
  • Fig. 17 is a graph of the product of viscosity and temperature, versus temperature, for Xenon, and within the operating temperature range of the present invention
  • Fig. 18 is a simplified view in longitudinal section for another embodiment of the invention.
  • Fig. 19 is a section taken at 19-19 in Fig. 18;
  • Fig. 20 is a view similar to Fig. 18, to show a modification;
  • Fig. 21 is an enlarged view in longitudinal section for a further embodiment of the invention.
  • Fig. 22 is a schematic section, taken generally at 22-22 of Fig. 21;
  • Fig. 23 is a simplified plan view of another embodiment.
  • Fig. 24 is a section taken at 24-24 of Fig. 23.
  • the basic laminated structure of one embodiment of a micro-gas rheostat of the invention is seen to comprise a bonded body of first and second laminations 10, 11, respectively, of elemental square, rectangular, octogonal, or other preferably regular polygonal planform, depicted as square in Fig. 3.
  • the consolidated body 10, 11 is cushioned and sealed by an elastomeric seal member 12 in its containment within a cupped housing member 13 having a reduced tubular end 14 for downstream discharge of a controlled gas flow through the micro-gas rheostat.
  • An electrically insulated pin connector formation 15 alongside the discharge end 14 enables detachable electrical connection to a source of electrical energy.
  • a radially flanged upper housing- closure member 16 has a reduced tubular end 17 for connection to a pressurized source of gas flow to be controlled by body 10, 11, pursuant to electrical input at 15 and within housing 13, 16, which is shown to be permanently sealed at a circumferential weld 18.
  • a conical element, with plural spaced apertures 19, distributes inlet gas to a circumferential first manifold 20, and plural spaced apertures 19' in seal member 12 distribute inlet gas into a second manifold 20' which is in full circumferential communication with circumferentially continuous exposure to the open (inlet) ends of the plural groove passages of inlet-filter structure 28, a so-called comb filter.
  • the consolidated body is seen to comprise a first flat lamination 10, which is preferably of single-crystal silicon and which is shown in Fig. 3 with its grooved surface facing up, to reveal the four walls 25 of the comb filter 28.
  • the comb filter consists of plural spaced parallel relatively narrow grooves 26 in each of the four walls 25; these grooves are closed by the glass lamination 11, so that each of the grooves 26 makes its gas-flow contribution in parallel with all other grooves 26, from the manifold 20' of Fig. 1, and into a further manifolding groove formation 27 within the peripheral walls 25.
  • the manifolding groove 27 has access to the inlet end of a helical groove formation, consisting of plural turns of interconnected leg segments of progressively diminishing length, with termination at an inner end 29 for downstream discharge at a central outlet 30 which is seen in Fig. 1 to be served by the outlet tube 14 of the housing member 13.
  • a helical groove formation consisting of plural turns of interconnected leg segments of progressively diminishing length, with termination at an inner end 29 for downstream discharge at a central outlet 30 which is seen in Fig. 1 to be served by the outlet tube 14 of the housing member 13.
  • individual groove widths are not drawn for the entire helical length of the single flow passage that they define; rather, a single line 31, with progressively shrinking helical courses a, b, c, d, e, f, g, serves to indicate the full helical path, and in Fig.
  • FIG. 6 the V-cut width, depth and spacing of representative adjacent helical courses b, c, d are shown to the same scale, for comparison in Fig. 7 with the narrower comb-filter grooves 26, having the lesser width and lesser depth.
  • FIG. 5 an illustrative heater layout of electrical-resistance material 32 is shown in application to the flat other surface of the silicon lamination 10. This heater layout effectively covers the entire lower surface of lamination 10, with lead wires 32, 32' to the external pin connector means 15 of Figs. 1 and IA.
  • the metal layer is preferably gold or aluminum that has been sputtered or electroplated onto the surface in the serpentine pattern shown, which is a pattern typical for resistance heating. It should be appreciated that there are two pins, providing positive and negative connections to the power source for the heater.
  • Fig. 9 illustrates the typical layout for multiple- element reproduction of plural micro-gas rheostats on and from the same single circular wafer 35, which may be of conventional 3-inch diameter and 0.015-inch thickness.
  • the double-line definition of 37 complete duplicate square configurations will be understood to suggest allowance for diamond saw or other cutting of - individual square elements (e.g., 0.375 inch by 0.375 inch) from the entire wafer.
  • the glass lamination is shown to be a 3.0 x 3.0 inch square panel which will be understood to have been bonded to all grooved surfaces throughout the wafer 35, prior to severance into single elements or multiple-element arrays.
  • Electrical energy to the heater pin connector may be continuous at various selected voltage levels, but it is presently preferred that electrical energy be supplied on a pulse-width modulation basis, so that a dwell period exists between successive input pulses.
  • the dwell period may be repeatedly used for monitoring (via suitable microchip pressure and temperature transducers) the instantaneous pressure levels P 1 and P 2 , as well as gas temperature, thereby to establish current mass flow of the rheostat-controlled gas flow.
  • the resistance of the heater or of the silicon can be measured with a local sensor, and since resistance is proportional to temperature, knowledge of the temperature of the chip implies the possible mass-flow rate at the time of that temperature; resistance- temperature devices (RTDs) are commercially available for a variety of applications.
  • mass-flow rate can be determined, using one or more temperature sensors responsive to average body temperature, together with measured inlet pressure and outlet pressure, as in conjunction with a predetermined calibration table.
  • the flow-rate turn-down ratio is set forth, commencing a unity turn-down ratio, for each of several starting or reference temperatures, namely, curve A starting at 32 F, curve B starting at 68 F, curve C starting at 120 F, and curve D starting at 160 F.
  • a dynamic flow- rate range of more than 4:1 is seen to be controllable over the 32 to 600 F range of curve A, and this range decreases for the successively greater starting temperatures for curves B, C, and D, so that for a 160 F starting temperature, curve D shows only a 2.75:1 range of flow-rate controllability.
  • FIG. 11 shows an idealized side view of a rheostat device housing 40 having an inlet-housing member 42 and an outlet-housing 44 providing fluid communication between an inlet tube 46 and a discharge tube 48 associated with respective housing members.
  • an electrical connection 50 Integral with the discharge or outlet-housing member is an electrical connection 50, the placement of which is a matter more of design choice, as its function is to provide electrical connection to the multilayer body 52 (as described before) .
  • the electrical connection is supported in an electrical connection formation 54 integral with the discharge housing.
  • the multilayer body (52) shown in phantom is supported in the rheostat device housing (40) which is preferably formed with a housing flange 41 of generally circular shape to facilitate placement of the device in tubing and other circular frames and flowpaths.
  • the electrical connection requires two inputs, shown as 50A and SOB, which are secured in the housing and electrically insulated therefrom by an insulating composition 56.
  • the insulating composition is preferably a borosilicate glass composition that has been fused in place at high temperature effective to maintain the resulting glass in compression; such processing is commercially available from Northeast Electronics Corp. , Milford, CT.
  • Line 13-13 of Fig. 12 provides the cross-sectional view of Fig. 13, in which the inlet housing (42) provides an inlet housing manifold 58 from the inlet tube (46) and formed by the attachment of the housings at a weld 59, to the discharge housing (44) supporting discharge tube 48.
  • a multilayer body 52 Disposed between the inlet and the discharge is a multilayer body 52 for controlling the flow of fluid, preferably gas, and most preferably a noble gas, especially Xenon, from the inlet to the discharge.
  • the multilayer body comprises a sealing glass layer 60, an intermediate flow-control layer 62, and a supporting glass layer 64, and is secured within the housing.
  • the seal connecting the body with the housing was an elastomeric material, which unfortunately inherently limits operating temperatures for the rheostat approximately to about 400 F maximum. Further, outgassing of elastomeric materials is very difficult for an environment such as the present, in which a high purity gas is metered under high tolerance and high flow-mass rate.
  • the glass layers (60, 64) are preferably of a composition having a coefficient of thermal expansion (COTE) approximating that of the intermediate flow-control layer, preferably silicon, in an operating-temperature regime of from about 0 (zero) to about 600 F.
  • COTE coefficient of thermal expansion
  • Various glass compositions having a suitable COTE are known, a preferred composition being grade-7740 glass available from Dow Corning (Ithaca, NY) .
  • the glass can be bonded to the silicon intermediate layer by various known techniques, a preferred method being anodic bonding (e.g. , Wallis, supra) .
  • anodic bonding entails providing a hot surface (typically 400-550 C) upon which the silicon layer is placed, and on top of which the glass layer is placed.
  • a voltage of about 1 kV is applied across the two layers (silicon at the cathode, glass the anode) , and the layers are pressed together under hermetic conditions to produce a silicon-glass laminate.
  • the silicon is made using microelectronic photoetching techniques, and is fabricated into a wafer form having multiple units thereon.
  • the anodic bonding is preferably conducted prior to the wafer being cut into individual components. Thus, by this preferred process, when the chips are cut, they are already in a multilayer configuration.
  • the housings are preferably made of a low-carbon stainless steel, such as 304L grade.
  • a low-carbon stainless steel such as 304L grade.
  • glass having a good COTE match to silicon cannot be well-bonded to stainless steels.
  • the multilayer body can be bound first to a KOVAR metal composition (generally containing iron, nickel, and cobalt).
  • the multilayer chip (52) has a supporting glass layer (64) by which the chip is secured to the housing at a back plate 66, also made of stainless steel (e.g. , 304L) .
  • a KOVAR foil layer 68 Between the stainless steel back plate and the supporting glass layer is a KOVAR foil layer 68, to which the glass can be bonded, and which can be supported by the stainless steel back plate 66.
  • the foil layer is spike welded (e.g. , laser or electron beam) to the back plate, which in turn is secured to the housing by a circular sealing ring 70 secured at weld 72 to the housing.
  • the support glass layer is secured to the foil layer by known methods, (e.g. , G. Wallis and D.I. Pomerantz, "Field Assisted Glass-Metal Sealing", Applied Physics, vol. 40, no. 10, 3946-3949 (Sept. 1969) ; the disclosure of which is incorporated herein by reference) .
  • the resulting structure provides a structurally isolated but bonded chip.
  • the chip is isolated from mechanical and thermal stresses induced upon the housing by the foil. For example, if the housing is subjected to a changed ambient temperature (i.e. , heated or cooled) , the housing will change dimensions (expand or contract) ; if the chip is bonded directly to the housing, then mismatch between the coefficients of thermal expansion (COTE) between the chip and the housing may be too great and result in the chip breaking.
  • COTE coefficients of thermal expansion
  • an elastomeric or polymeric gasket is used to secure the chip, then outgassing of the organic material during start-up or at higher operating temperatures can cause significant problems in regulating the flow; outgassing can occur when volatiles are released from the organic/polymeric material as it is heated or as the local pressure is lowered. Most preferably, then, it is desired to eliminate the presence of all non-metallic, especially non-inorganic, components.
  • the present invention provides a solid state flow control device isolated from stress of the housing in which it is protected. As such, it is also preferable to keep the back plate (66) as thin as possible to minimize thermal conduction from the housing to the chip.
  • Figs. 14 and 15 respectively depict the top view and a cross-section of a modified intermediate flow-control layer (62) , wherein the sealing glass layer (60) is bonded to the significantly photoetched surface of the flow- control layer.
  • Etching is preferably done by techniques well-known in the semiconductor fabrication industry, and such etching typically occurs along one or more of the [111] planes of the silicon; single-crystal silicon is typically provided commercially as a wafer having a polished [100] surface.
  • V-shaped grooves are formed by allowing the etchant to penetrate fully, so that the co-etching walls meet at the bottom of the "V” , whereas channels with a flat bottom surface denote areas where the etchant was stopped prematurely, before the etching walls would otherwise meet at the bottom of the channel.
  • the sealing glass layer has inlet ports 74 which lead to the inlet manifolds 80 etched in the chip. The gas then passes through a series of comb filters 82, into the trough 84, and then into the capillary tube 86 for exit through the exit port 88.
  • the respective areas of the manifolds, troughs, capillaries, and filters are about 94.55, 78.79, 10.72, and 2.04 x 10 "6 in 2 .
  • There are a multiplicity of comb filters so that a number of the filters can become plugged without significantly diminishing the combined cross-sectional area for the filters to near that of the other flow channels; thus, a plugged filter element will not significantly limit flow.
  • the edges of the flow-control layer have a flat electrode surface 90 upon which an electrically conducting metal layer 92 (e.g. , gold) is deposited (such as by sputtering) and connected to the electrical pins (50) by wire leads 94, preferably by ultrasonic ball bonding (a technique well-known in the microprocessor fabrication industry) .
  • an electrically conducting metal layer 92 e.g. , gold
  • wire leads 94 preferably by ultrasonic ball bonding (a technique well-known in the microprocessor fabrication industry) .
  • the mass-flow rate (m) decreases as the temperature of the device increases.
  • the present invention controls the mass flow from an inherent maximum (based on the differential pressure) to a minimum based on the temperature which the intermediate control layer imparts to the gas.
  • the gas flow leaves from the exit (88) through a port 96 in the glass support layer (64) and an aligned port 98 in the back plate (91) and out through the discharge tube (48) .
  • the inner surface of the inlet-housing manifold (58) is preferably polished to reflect heating radiation (e.g., radiation emanating from the silicon flow-control layer) back onto the flow-control layer, and the outer surfaces of the glass layers can be plated to further reflect radiation back onto the chip surface.
  • heating radiation e.g., radiation emanating from the silicon flow-control layer
  • the outer surfaces of the glass layers can be plated to further reflect radiation back onto the chip surface.
  • reflective materials include aluminum, silver, and gold, and mixtures and alloys thereof.
  • the multilayer body is preferably attached to the housing, via the foil (68) and back plate, along only a portion of the support-glass side.
  • a central portion of the support glass layer (64) is etched in a circular shape to provide a circular land or boss 100, and it is this boss that is sealed to the foil layer (68) .
  • the reduced contact between the glass and the foil because of joining only at the boss, inhibits conductive heat loss from the multilayer body to the housing.
  • the boss provides a span to which the chip can be securely and hermetically bonded, providing mechanical isolation of the chip from the housing and assuring that the fluid flow is conducted through the chip and does not leak around the chip's supporting structure.
  • the present device has a number of applications in environments where it is desirable to control the flow of a gas, and possibly of some liquids.
  • environments include apparatus such as gas chromatographs and other analytical and medical instrumentation and control systems.
  • the present device is particularly useful for controlling the flow of thruster gas to a microthruster. Because the thrust force is a function of the amount of mass ejected and its velocity, the velocity being a function of the pressure drop and the presence of a nozzle, the thrust force and duraction can also be controlled, at least in part, using the micro-gas rheostat of the present invention. For example, the present device can throttle down the gas flow to the microthruster when smaller thruster bursts are required.
  • This invention can be an element of a closed-loop control -system.
  • the thrust and the power to the thruster can be measured, and they can be effectively varied by throttling the gas mass supply flow down or up to alter the thrust and the power used by the thruster.
  • the invention can be a closed-loop control system in and of itself, wherein the resistance of the heater or the chip is measured and, knowing or measuring the pressure drop across the rheostat, the mass-flow rate can be determined.
  • a temperature set point can be used indirectly as a mass-flow set point, and the output of a comparitor (comparing the actual temperature and the set point, or the inversion of the output signal) can be used to control the current sent to the heater or chip.
  • control systems can be in the form of an integrated circuit also located within the housing or even etched onto a portion of the solid state rheostat itself.
  • Figs. 18 and 19 is illustrative of a mechanical arrangement wherein a flow-control chip 100, which may be one of several varieties already described, is ruggedly and entirely supported by an annular insert 101 of glass (suitably a borosilicate glass) that is bonded with the central bore of an element 102 of an upper housing 103.
  • annular insert 101 of glass suitable a borosilicate glass
  • the bore of insert 101 is bonded to the outlet tube 104, such that at the interior end of bonded elements 101, 102, 104, the end of insert 101 projects as an annulus downwardly away from elements 102, 104, thus enabling a polishing operation on this projecting end, the polishing operation being to assure a high quality flat annular end surface of element 101 to be assembled, -preferably by an anodic bond, to the similarly flat upper surface of the silicon layer 105 of chip 100.
  • the position and orientation of chip 100, and particularly the lower surface of its glass support layer 106 may thus be precisely controlled for a predetermined offset ⁇ of chip 100 from a lower plane of reference to housing element 102, prior to assembling a shouldered ring 107 to element 102, to complete the upper housing 103.
  • the ring 107 is suitably of stainless steel, inertia-welded to the Kovar of upper housing element 102.
  • the lower housing 108 is a precision subasse bly for mounting the electrical heater means 109 in uniform closely spaced offset from the lower surface of the support-glass layer 106 of chip 100.
  • lower housing 108 is cup-shaped and suitably of stainless steel, providing a skirt 110 which is later nested to the shoulder of ring 107.
  • the bottom of the cup-shape of lower housing 108 features diametrically opposite parallel bores for annular glass inserts 111 which mount the respective feed-throughs 112-112' for rugged support and precise positioning of heater means 109.
  • the feed- throughs 112-112' are suitably of Kovar or stainless steel, and the glass of inserts 111, and their bonded relation to Kovar or stainless steel, may be as described for the insert 101.
  • the lower housing 108 is illustratively completed by a central inlet port and tube formation 113, and lower-housing to upper-housing assembly is shown permanently completed by a peripherally continuous weld 114 of the nested relation.
  • tube 104 is the inlet and tube 113 is the outlet
  • comb-filter etching be provided upstream from the flow-control grooves, i.e., between the central inlet opening and the point of gas-flow supply to the region of flow-control groove system, and with the flow-control groove system discharging via tube 113.
  • Figs. 21 and 22 is illustrative of a variation of the embodiment of Figs. 18-20, wherein a single cup-shaped housing member 120 has a skirt portion - characterized by a counterbore into which a preasse bly of an operative flow-control chip 122, with electrical connections 123, 123 ' , is integrated into a single housing closure component 124 which is externally configured for precise and stabilized seating engagement within the bore and counterbore features of housing member 120.
  • a large central bore in closure component 124 has bonded cylindrical interface with an annular glass (dielectric) insert 125 (corresponding to the configuration and function of insert 101 in Figs.
  • a central outflow tube 126 has bonded cylindrical interface with the bore of insert 125, and the polished lower projecting annular end face of insert 125 has an anodized bond to the upper flow-control layer of chip 122, thereby providing essentially the sole means of chip support with respect to the housing.
  • the electrical feed-through elements 123, 123' of Figs. 21 and 22 are integrated into the single subassembly carried by and within the cylindrical outer surface of housing- closure member 124, these electrical elements 123, 123' being mounted by annular glass (dielectric) inserts 126, to diametrically opposite bores in closure member 124, in the manner described at ill in connection with Figs. 18, 19.
  • the gas-rheostat chip 122 is shown to be square, with side-to-side spacing that is evident from the sectioned area of the chip, as seen in Fig. 21, the diagonal extent of the chip being suggested in Fig. 21 by phantom extensions 127, as will be seen in Fig. 22 to apply on the diagonal alignment 2l'-21' of Fig. 22, which illustratively shows the radially undulating course of two-like heater elements A, B having opposite semicircular courses, in parallel, between diametrically opposite metal terminals or contacts 130, 131 on the upper surface of chip 122 and at diagonally opposed corners of the square - (on alignment 21-21), for the sake of clarity in Fig.
  • each of the feed-through elements 123, 123' is shown carrying a compliantly cantilevered arcuate contact-wiping arm 132, 132', in resiliently loaded contact with the metal terminals 130, 131 on the upper flat surface of chip 122.
  • a sealed flow-control groove 133 of expanding-helix nature is shown, by phantom suggestion, to be in register with the heater elements A, B, and thus with the peripherally continuous outer annular region of chip 122.
  • inlet tube 121 of the housing- closure assembly to member 124, and in outlet tube 134 of the cupped housing element 120 illustrate the single direction of inlet flow and of rheostat-controlled outlet flow from the housing.
  • the inlet flow has direct and exclusive access to a central port 135 of chip 122 which has manifolded radially outward gas entry into a four-leg comb-filter region 136, it being noted that the four legs of the comb filter are largely lapped by the cross-hatched annular region of bonded support of chip 122 by the annular member 125 of dielectric material (glass) .
  • Figs. 23 and 24 illustrates that the gas rheostat 122', as at 122 of Figs. 21 and 22, may be built with a hexagonal planform, which may be preferable for certain housing and electric-terminal purposes (other than those of Figs. 21 and 22) .
  • FIG. 23 Corresponding parts of the flow accommodation in Figs. 23 an d 24 are therefore shown with the same reference-number identifications, as described for Figs. 21 and 22, but with primed notation.
  • inlet flow via central opening 135' is shown as having manifolded access, in the radially outward direction, to the four legs of comb- filter means 136'; and the comb filters discharge via manifolding means 137' and passage 138' to the inlet end of the expanding helix course of the flow-control passage 133'.
  • the other end of the flow-control passage will be understood to open at 139' into the interior volume of the closed housing (not shown in Figs. 23 anmd 24) , for exit flow from the involved housing.
  • dashed lines 145 along opposite sides of the hexagonal planform of the chip 122' will be understood to suggest another technique of chip mounting to suitable ledge or shoulder means which constitutes a supporting feature of the internal profile of one of the housing elements.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Remote Sensing (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Theoretical Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Micromachines (AREA)

Abstract

L'invention concerne un dispositif et un procédé pour réguler de faibles écoulements de gaz pour des propulseurs d'orientation de satellite. Ce dispositif comporte un corps silicium photogravé (10) dont la gravure permet d'obtenir un ou plusieurs trajets d'écoulement particuliers, et éventuellement des filtres, le trajet d'écoulement étant défini par le corps silicium (10) et une couche de verre de scellement (11) adhérisée sur celui-ci. L'écoulement est régulé, par l'intermédiaire du ou des trajets d'écoulement, par chauffage du corps (10) pour diminuer l'écoulement de gaz.
PCT/US1997/009962 1996-06-07 1997-06-06 Rheostat a micro-gaz WO1997047013A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP97929874A EP1008146A1 (fr) 1996-06-07 1997-06-06 Rheostat a micro-gaz
JP10500913A JP2000512780A (ja) 1996-06-07 1997-06-06 マイクロガスレオスタット

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US65996596A 1996-06-07 1996-06-07
US08/659,965 1996-06-07

Publications (2)

Publication Number Publication Date
WO1997047013A1 true WO1997047013A1 (fr) 1997-12-11
WO1997047013A9 WO1997047013A9 (fr) 1998-03-19

Family

ID=24647557

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1997/009962 WO1997047013A1 (fr) 1996-06-07 1997-06-06 Rheostat a micro-gaz

Country Status (4)

Country Link
EP (1) EP1008146A1 (fr)
JP (1) JP2000512780A (fr)
CA (1) CA2257341A1 (fr)
WO (1) WO1997047013A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000012903A1 (fr) * 1998-09-01 2000-03-09 Institut für Physikalische Hochtechnologie e.V. Commutateur de flux miniaturise
JP2000249112A (ja) * 1999-02-25 2000-09-12 Vacco 流体モジュール形成用エッチング薄板の組立方法
EP1215399A2 (fr) * 2000-12-12 2002-06-19 Eastman Kodak Company Microvalve et procédé pour le contrôle du flux d'un liquide
US6866060B2 (en) 2001-09-25 2005-03-15 Festo Ag & Co. Valve means

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1486682A3 (fr) * 2003-06-11 2005-07-20 LG Electronics Inc. Micro-actionneur, procédé pour sa fabrication, et soupape à micro-actionnement
FI129831B (en) 2020-04-02 2022-09-15 Aurora Propulsion Tech Oy Push assembly

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1069597A (en) 1912-12-07 1913-08-05 Wyatt Boyd Molding-machine.
US3279177A (en) * 1963-06-10 1966-10-18 Giannini Scient Corp Apparatus and method for propelling vehicles in space
US4474889A (en) * 1982-04-26 1984-10-02 Microsensor Technology Inc. Miniature gas chromatograph apparatus
US4604090A (en) 1983-11-22 1986-08-05 Consolidated Controls Corporation Compact implantable medication infusion device
US4656828A (en) * 1984-09-28 1987-04-14 Rca Corporation Augmentation heater temperature control system
US4715852A (en) 1986-07-21 1987-12-29 Eaton Corporation Implanted medication infusion device
US4935040A (en) * 1989-03-29 1990-06-19 The Perkin-Elmer Corporation Miniature devices useful for gas chromatography
US5027596A (en) * 1988-07-16 1991-07-02 Erno Raumfahrttechnik Gmbh High performance propulsion thruster, especially for attitude and orbit control of a space flight body
US5323999A (en) * 1991-08-08 1994-06-28 Honeywell Inc. Microstructure gas valve control
US5544276A (en) * 1993-11-30 1996-08-06 Microsensors Technology, Inc. Miniature gas chromatograph with heated gas inlet fitting, heated tubing, and heated microvalve assembly

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1241867A (en) * 1968-12-31 1971-08-04 James Ephraim Lovelock An improved method and apparatus for controlling the flow of gases
JPS62108156A (ja) * 1985-11-07 1987-05-19 Sord Comput Corp シリコン・ウエハ−キヤピラリイ・カラム
US5267584A (en) * 1990-10-16 1993-12-07 Smith Richard D Method of fluid flow control using a porous media
EP0733169B1 (fr) * 1993-10-04 2003-01-08 Research International, Inc. Appareil de traitement de fluides micro-usine comprenant un filtre et un regulateur de debit

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1069597A (en) 1912-12-07 1913-08-05 Wyatt Boyd Molding-machine.
US3279177A (en) * 1963-06-10 1966-10-18 Giannini Scient Corp Apparatus and method for propelling vehicles in space
US4474889A (en) * 1982-04-26 1984-10-02 Microsensor Technology Inc. Miniature gas chromatograph apparatus
US4604090A (en) 1983-11-22 1986-08-05 Consolidated Controls Corporation Compact implantable medication infusion device
US4656828A (en) * 1984-09-28 1987-04-14 Rca Corporation Augmentation heater temperature control system
US4715852A (en) 1986-07-21 1987-12-29 Eaton Corporation Implanted medication infusion device
US5027596A (en) * 1988-07-16 1991-07-02 Erno Raumfahrttechnik Gmbh High performance propulsion thruster, especially for attitude and orbit control of a space flight body
US4935040A (en) * 1989-03-29 1990-06-19 The Perkin-Elmer Corporation Miniature devices useful for gas chromatography
US5323999A (en) * 1991-08-08 1994-06-28 Honeywell Inc. Microstructure gas valve control
US5544276A (en) * 1993-11-30 1996-08-06 Microsensors Technology, Inc. Miniature gas chromatograph with heated gas inlet fitting, heated tubing, and heated microvalve assembly

Non-Patent Citations (7)

* Cited by examiner, † Cited by third party
Title
GEORGE WALLIS: "electrocomponent science and technology", vol. 2, part 1 1975, article "field assisted glass sealing", pages: 45 - 53
GEORGE WALLIS: "electrocomponent science and technology", vol. 2, part 1 1975, article "field assisted glass-metal sealing, infra"
JAMES B. ANGELL ET AL: "sci. am.", April 1983, article SILICON MICROMECHANICAL DEVICES, pages: 42 - 56
K.N. KOZUBSKY ET AL: "aiaa/sae/asme/asee 29 th joint propulsion conf. and exhibit, june 28-30, 1993, monterey, california (aiaa-93-1787)", 1993, article "plan and status of the development and qualification program for the stationary plasma thruster"
KURT E PETERSEN: "proc. ieee", vol. 70, part 5 May 1982, article "silicon as a mechanical material", pages: 400 - 457
See also references of EP1008146A4 *
WALLIS AND D.I. POMERANTZ: "applied physics", vol. 40, part 10 September 1969, article "field assisted glass-metal sealing", pages: 3946 - 3949

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000012903A1 (fr) * 1998-09-01 2000-03-09 Institut für Physikalische Hochtechnologie e.V. Commutateur de flux miniaturise
US6497252B1 (en) 1998-09-01 2002-12-24 Clondiag Chip Technologies Gmbh Miniaturized fluid flow switch
JP2000249112A (ja) * 1999-02-25 2000-09-12 Vacco 流体モジュール形成用エッチング薄板の組立方法
EP1031734A3 (fr) * 1999-02-25 2001-07-25 Vacco Assemblage de plaques gravées formant un module fluidique
US6334301B1 (en) 1999-02-25 2002-01-01 Vacco Industries, Inc. Assembly of etched sheets forming a fluidic module
EP1215399A2 (fr) * 2000-12-12 2002-06-19 Eastman Kodak Company Microvalve et procédé pour le contrôle du flux d'un liquide
EP1215399A3 (fr) * 2000-12-12 2003-11-12 Eastman Kodak Company Microvalve et procédé pour le contrôle du flux d'un liquide
US6866060B2 (en) 2001-09-25 2005-03-15 Festo Ag & Co. Valve means

Also Published As

Publication number Publication date
JP2000512780A (ja) 2000-09-26
CA2257341A1 (fr) 1997-12-11
EP1008146A4 (fr) 2000-06-14
EP1008146A1 (fr) 2000-06-14

Similar Documents

Publication Publication Date Title
US6141497A (en) Multilayer micro-gas rheostat with electrical-heater control of gas flow
US5441597A (en) Microstructure gas valve control forming method
US7732086B2 (en) Bonded polyimide fuel cell package
US5927325A (en) Microelectromechanical machined array valve
Köhler et al. A hybrid cold gas microthruster system for spacecraft
US5176358A (en) Microstructure gas valve control
US7169006B2 (en) Thermionic vacuum diode device with adjustable electrodes
US7538401B2 (en) Transducer for use in harsh environments
Yang et al. Leak-tight piezoelectric microvalve for high-pressure gas micropropulsion
US7122261B2 (en) Metal hydride fuel storage and method thereof
EP0469749A1 (fr) Soupape de contrôle utilisant élément de flambage
KR20000048700A (ko) 일체로 된, 전기적으로 작동 가능한 마이크로-밸브
US6283440B1 (en) Apparatus and method for regulating fluid flow with a micro-electro mechanical block
JPH09505130A (ja) ミクロ機械加工された弁装置
EP1008146A1 (fr) Rheostat a micro-gaz
WO1997047013A9 (fr) Rheostat a micro-gaz
US7789371B2 (en) Low-power piezoelectric micro-machined valve
US8407980B2 (en) Microthruster
KR19980083719A (ko) 열팽창 물질을 이용한 유량조절밸브
Yang et al. Resealable, ultra-low leak micro valve using liquid surface tension sealing for vacuum applications
US20080265192A1 (en) High Pressure Isolation Valve System
EP1103714A2 (fr) Micropropulseur avec tuyère conique
Bejhed et al. Demonstration of a single use microsystem valve for high gas pressure applications
Mueller et al. Design and fabrication of MEMS-based micropropulsion devices at JPL
RU2777015C1 (ru) Кварцевый резонатор с частичным внутренним размещением элементов термостата генератора

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): CA JP RU

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
COP Corrected version of pamphlet

Free format text: PAGES 2/9 AND 4/9-9/9, DRAWINGS, REPLACED BY NEW PAGES BEARING THE SAME NUMBER; DUE TO LATE TRANSMITTAL BY THE RECEIVING OFFICE

121 Ep: the epo has been informed by wipo that ep was designated in this application
ENP Entry into the national phase

Ref document number: 2257341

Country of ref document: CA

Ref country code: CA

Ref document number: 2257341

Kind code of ref document: A

Format of ref document f/p: F

WWE Wipo information: entry into national phase

Ref document number: 1997929874

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 1997929874

Country of ref document: EP

WWW Wipo information: withdrawn in national office

Ref document number: 1997929874

Country of ref document: EP