US3814998A - Pressure sensitive capacitance sensing element - Google Patents
Pressure sensitive capacitance sensing element Download PDFInfo
- Publication number
- US3814998A US3814998A US00361813A US36181373A US3814998A US 3814998 A US3814998 A US 3814998A US 00361813 A US00361813 A US 00361813A US 36181373 A US36181373 A US 36181373A US 3814998 A US3814998 A US 3814998A
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- US
- United States
- Prior art keywords
- core
- sensing element
- electrodes
- dielectric
- capacitance sensing
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- Legal status (The legal status 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 status listed.)
- Expired - Lifetime
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/0041—Transmitting or indicating the displacement of flexible diaphragms
- G01L9/0072—Transmitting or indicating the displacement of flexible diaphragms using variations in capacitance
Definitions
- a diaphragm element includes thin outer conducting layers integrally bonded to the opposite sides of a core layer of silicone or other dielectric which is a resilient, flexible material, to form a single, integral, resilient, flexible structure.
- the conducting layers are a matrix of the material of the dielectric core layer with carbon or like particles embedded therein.
- One conducting layer is spaced peripherally from the edge of the core layer to thereby prevent electrical contactbetween the two conducting layers.
- the total unit is rigidly mounted about the peripheral edge with metallic contacts connected to the conducting layers as by a silver conducting paint applied to the outer surface of the layers. The element will thus flex to the side of the lower pressure with a change in the effective conducting area of the opposite conducting layers and a simultaneous decrease in the thickness of the dielectric inner core. Consequently, the capacitance of the unit varies as a function of the deflection and thereby in accordance with the pressure differential applied across the diaphragm element.
- a capacitance type pressure to electrical signal transducer is a very common form of a transducer employed in modern technology. Generally, they take either one of two forms.
- a fixed or stationary electrode forms a base structure for the sensing unit.
- a dielectric material which may be a fluid, is supported by the stationary electrode.
- a conductive outer plate is movably mounted abutting the dielectric material and exposed to the pressure condition to cause flexing of the dielectric material with a corresponding change in the capacitance characteristic.
- a conductive diaphragm is movably mounted between a pair of stationary electrode plates for movement parallel to the plates and coupled to the pressure source for corresponding positioning between the two fixed plates to thereby vary the capacitance.
- Capacitive sensing units are desirable because of the stability of their characteristic as long as the integrity of the sensing elements are maintained.
- the electrode plates are relatively fragile members and present some difficulty in connection with production, particularly in a mass production process. Further, a trapped dielectric fluid is often employed between the plates. As a result of the relative moving of an element in the unit, the fluid is subject to exposure to the environment and contamination by environmental borne dust and the like. This may change the characteristic of the sensor and may, in fact, result in actual shorting of the electrode plates. Further, the fluid dielectric medium may be lost, at least in part, resulting in a distinct change in the characteristic of the sensor.
- the present invention is particularly directed to a pressure sensitive capacitance sensing unit which is readily adapted to production on a commercial basis and which provides long life with high stability in use.
- the capacitance sensing unit includes an inner core and outer electrode plates having an elastic portion which is subject to elastic deformation as a result of a pressure or force differential impressed across the unit and with the capacitance directly related to the deformation.
- the capacitor sensing unit includes therebetween which will flex or bulge in accordance with a pressure differential which is applied across the diaphragm element between the mounting means.
- the sensing element At zero pressure, the sensing element is in an unstressedstate and the capacitance is dependent upon the basic area of the conductive layer and the thickness of the dielectric core as well as the permittivity of the dielectric core.
- the sensitivity in turn is dependent on the relative size of the element and the composite elastic modulus of the total diaphragm element which, in turn, is a composite of the elastic modulus of the inner core and the outer two conducting layers.
- The. diaphragm element of the present invention preferably includes the integral attachment of thin outer conducting layers to the opposite sides of a sheet of the dielectric core material.
- the conducting layers are preferably deposited on the core and integrally bonded throughout the mating faces to form a single integral flexible structure.
- the thickness of the conducting layers as well as the elastic modulus of the conducting layers for optimum results should be less than or equal to the corresponding characteristic of the core layer.
- the conducting layers may advantageously be formed of a matrix which is similar to the dielectric core layer or another material which can be integrally bonded thereto. Disposed within the conducting layers are suitable electrically conductive particles such as carbon and the like, with the amount of the particles selected to provide the desired conductivity without significantly interfering with the elastic characteristics, stability, and response to pressure change of the total unit.
- the core dielectric material as well as the outer flexible conductors should have excellent resistance against plastic deformation'such that the element may provide reliable and repeatable response to pressure changes.
- one of the conducting layers is spaced peripherally from the edge of the core layer to thereby prevent electrical contact between the two conducting layers.
- the total unit is rigidly mounted about the peripheral edge of the element.
- the rigid mounting for the units preferably includes metallic contacts connected to the conducting layers by a silver conducting paint applied to the outer surface of the layers. Suitable lead wires are connected to the contacts and connected in a circuit such that the capacitance characteristic of the
- the inner core is formed of a silicone elastomer which has a dielectric constant of between 1.1 to 25 and preferably approximately 3.
- the elastic modulus may also vary significantly for example between I to 1,000,000 psi but optimum results have been found employing materials with an elastic modulus of 50 to 1,000 psi.
- the core layer thickness can also vary widely with a range of from0.000l inch to 0. 1000 inch.
- the flexible core with the bonded outer flexible electrodes produces a highly sensitive flexible membrane or diaphragm construction which can be readily produced. Further, an integrally bonded construction essentially prevents any danger of air pocket developments or the entry of dust and other foreign material into the dielectric portion of the unit and thereby not only prevents the possibility of shorting the capacitance plates but prevents relative changes in the characteristic in the capacitors dielectric and therefore in the capacitance characteristic.
- FIG. 1 is a plan view of a pressure sensitive capacitance sensing element constructed in accordance with the present invention
- FIG..2 is a vertical section taken 2-2 of FIG. 1;
- FIG. 3 is an enlarged fragmentary section taken generally on line 3'3 of FIG. 1 illustrating a highly satisfactory construction of the elements forming the flexible portion of the sensing element;
- FIG. 4 is an illustration of the sensing elements response to a pressure differential when connected in a suitable electric output circuit
- FIG. 5 is a view similar to FIG. 1 illustrating an alternative embodiment of the invention.
- FIG. 6 is a fragmentary section taken generally on line 66 of FIG. 5.
- a pressure sensitive capacitance sensing unit constructed in accordance with the present invention is shown including an outer annular pair of supporting rings 1 and 2 with a flexible pressure sensitive diaphragm 3 rigidly clamped therebetween.
- the rings 1 generally on line and 2 may be interconnected by a plurality of equicircum ferentially distributed clamping screws 4 which, when drawn up, form a firm integrated structure and in particular rigidly support the flexible diaphragm 3 completely about the embodiment.
- the diaphragm element thus defines a pair of distinct opposite sides or surfaces, one of which is subjected to a first or reference pressure 5 and the opposite side of which is connected to a second pressure 6 to be sensed, as diagrammatically illustrated in FIG. 2.
- diaphragm 3 is especially constructed as a flexible assembly which includes a central core 7 shown as a sheet-like member 4 of a dielectric material with flexible electrode layers 8 periphery thereof in the illustrated and 9 firmly attached in abutting relation to the opposite faces of the core 7.
- a central core 7 shown as a sheet-like member 4 of a dielectric material with flexible electrode layers 8 periphery thereof in the illustrated and 9 firmly attached in abutting relation to the opposite faces of the core 7.
- the three layer diaphragm projects laterally with all three layers being firmly held by the rings 1 and 2.
- the core 7 is formedof a dielectric material and the electrodes 8 and 9 are formed of a conductive material and all three have an elastic modulus to permit the clastic movement from the rigid mounting position.
- the flexible diaphragm is such, therefore, that a differential pressure arising as a result of a difference in the signal pressure 6 and the reference pressure 5 results in a corresponding movement of the diaphragm 3.
- the unit bulges and flexes in accordance with the differential pressure, as shown in phantom at 10 in FIG. 2.
- the area of a curved surface is greater than the projected flat area and the movement of the diaphragm therefore effectively increases the area of the electrode layers 8 and 9.
- This increase in differential pressure also results in a thinning of the multilayer diaphragm, including its core 7 which is similarly flexed, simultaneously reducing the core thickness and therefore reducing the spacing between the electrode plates.
- diaphragm 3 The deflection of diaphragm 3 to the phantom line position clearly indicates the increased area of layers 8 and 9 and decreased thickness of the dielectric material 7.
- the capacitance will increase with the bulgingmovement of the diaphragm 3, as a result of the increased area A and also as a result of the decreased thickness t and will correspondingly decrease as the capacitance diaphragm moves back to the full-line, balanced position.
- the outer electrodes 8 and 9 are for optimum results integrally bonded throughout their interfaces 11a to the adjacent core layer 7 such that the element moves as a single integrated element.
- the top electrode 8 is shown formed of a smaller diameter with the periphery within the line of bolts 4. This prevents shorting of the plates. Any other suitable means can, of course, be used.
- the dielectric core layer 7 is, of course, electrically insulating and formed of an elastic material which is advantageously relatively non-porous to the fluid medium to the opposite sides of the diaphragm.
- a silicone elastomer having a dielectric constant of about 3, an elastic modulus of about 500 psi and a resistivity of the order of l X 10" microhm cm has been found to be a satisfactory material for the dielectric core.
- the dielectric constant of the core can readily vary from a dielectric constant of 1.1 to 25.
- the elastic modulus of the core layer can readily vary between 1 psi and 1,000,000 psi with more typical values ranging from 50 psi to 1,000 psi.
- a typical resistivity of the insulating core is about 1 X microhm cm.
- the thickness of core layer 7 may readily vary from 0.0001 inch to 0.1000 inch. In practical applications, applicants have found a range of 0.0003 inch to 0.0200 inch to provide particularly useful results.
- the conducting layers or electrodes may be formed of any suitable material, they are advantageously formed as a matrix with a base which is similar to the dielectric core layer material such as silicone such as graphitized carbon and deoxidized carbon are dispersed through the conducting electrodes such that they define conductive plates ofv an elastic nature.
- the conducting electrodes 8 and 9 may be constructed in any suitable manner, for example, by dispersing of graphitized carbon through a silicone elastomer, as more fully disclosed in US. Pat. No. 3,582,728.
- the one electrode layer 8 or 9 can readily be cast as a film on a clean glass plate.
- the dielectric core 7 is thereafter applied on the film and interconnected to the electrode by cross linking.
- the outer electrode is cast as an appropriate film over the core layer andinterconnected by cross linking.
- Optimumresults are obtained by maintaining the elastic modulus of the conducting layers 8 and 9 at values'less than or equal to that of the core layer 7 and similarly of a thickness which is less than or euqalto that of the core layer.
- the. diaphragm 3 should, of course, be formed of a material which also has excellent resistance toplastic deformation such that the element returns to the balanced pressure position to maintain accurate and repeatable outputs with varying pressure input. If it does not, the unit will, of course, plastically deform with pressure changes and result in a variation in a subsequent response of the element to the same pressure change.
- the conducting layers and the core layer are formed of a suitable material which is relatively non-porous to the fluid medium. If the layers are porous, the pressure would, of course, be transmitted through the unit and correspondingly reduce the sensitivity of the unit to pressure changes.
- the bottom conducting layer 9 is coextensive with the dielectric core layer 7.
- the opposite or top conducting layer 8 is spaced from the peripheral edge of the dielectric core layer 7. This ensures effective spacing between the two electrodes 8 and 9 and minimizes, creation of electrical contact therebetween with the resulting shorting of the electrode plates.
- Circuit connections are made to the conducting electrodes in any suitable manner.
- the conducting layers 8 and 9 within the clamping rings 1 and 2 may be provided with a spot coating of a silver conductingpaint l2 and 12a to provide connection to the conductive particles 11 within the layers 8 and 9.
- Metallic contacts 13 and 114 within the rigid mounting elements 1 and 2 are aligned with and make contact with the silver conducting paint l2 and 12a.
- Lead wires 15 and 16 are connected to the metallic contacts and provide connection of the capacitance sensing element in any suitable system.
- the pressure sensing element for example, may be connected into a leg of an alternating current bridge circuit, not shown, which is energized from a suitable alternating current source.
- the balanced condition, and therefore, the output, of the bridge is responsive to the capacitance of the capacitance element.
- the output is such that it can be readily detected and amplified by a suitable amplifier or the like to energize a suitable detection or control load.
- FIG. 4 The characteristic of a unit such as shown in FIGS. 1 and 2 is shown in FIG. 4.
- the characteristic of FIG. 4 is illustrative of a unit having an active conducting area in the balanced position as shown in FIG. 2 of 0.60 square inches.
- the dielectric core 7 was 0.0004 inch thick and the outer conducting layers 8 and 9 were of a corresponding thickness, and were formed as sheetlike layers bonded to the core as previously described with reference to US. Pat. No. 3,582,728.
- the core layer was a silicone elastomer with a dielectric constant of 3.0.
- the conducting layers were similarly a silicone elastomer matrix with a conductive carbon particle uniformly dispersed therein.
- the test was run with atmosphere as a reference pressure and with air pressure supplied to the opposite side of the capacitance element.
- the circuit was energized from an alternating current source of a thousand cycles per second and readings taken at increments of 1 inch of water.
- the capacitance changes essentially in accordance with a straight line function between approximately 328 picofarads at zero signal pressure to 365 picofarads at 15 inches of water.
- the sensitivity of the unit corresponds essentially to the slope of the illustrated curve and was essentially 2.5 picofarads per inch of water.
- FIGS. 5 and 6 An alternative embodiment is shown in FIGS. 5 and 6 having three bonded elements, and elements corresponding to the elements of the first embodiment are similarly numbered for simplicity and clarity of explanation.
- the one elec-' trode plate, shown as the top plate 17, is especially formed and applied to minimize the projection beneath the clamping ring 1. This minimizes the hysteresis of the element and further contributes to the stability and performance of the unit.
- the electrode plate 17 is a circular element of a slightly smaller diameter than the inner diameter of the ring I.
- the plate 17 is bonded or otherwise suitably affixed to the core with a circumferential space or gap 18 extending essentially completely about the unit.
- a small tab-like extension 19 is integrally formed on the edge of plate 17 and aligned with the contact 13, shown only in FIG. 3, of the ring I. to provide connection to the electrode.
- the bonded plateconstruction is particularly significant in the practical construction and application of the capacitive sensor.
- the construction provides a simple mechanism which is relatively stable and relatively rugged.
- the outer carbon plates tend to be somewhat sensitive to tearing and would be subject to breakage.
- the interconnected bonding to the interior dielectric provides significant support to the plates.
- the capacitance sensing element of the present invention thus provides a relatively simply constructed peatable outputs or output characteristics.
- a pressure sensitive capacitance sensing element comprising a core formed of a dielectric material, a plurality of electrically conductive electrodes interconnected with said core layer to define capacitor plates to the opposite side of such core and defining a capacitor unit, said capacitor unit being elastic and having fixed mounting means at spaced points of the capacitor unit with the unit elastically moving with respect to the said fixed mounting means and correspondingly elastically deforming the capacitor unit with an increased conductive area of the electrodes with respect to said mounting and a decreased dielectric core thickness to thereby provide a change in the capacitance of the element.
- sensing element of claim 1 wherein said dielectric core and said electrically conductive electrodes are flexible solid elements and the electrodes are integrally bonded throughout the interface to the dielectric core.
- each of said electrodes include electrically conductive particles distributed throughout an electrically insulating material.
- each of said conductive electrodes are formed of the same material as said core and having electrically conductive particles distributed throughout the electrode.
- the capacitance sensing element of claim 1 wherein the one conducting layer is coextensive with the dielectric core and the opposite electrode is spaced from the periphery of the core, and having a peripheral mounting means extending over at least one of the electrodes to establish said fixed mounting means of said spaced points.
- the capacitance sensing element of claim 1 having a peripheral mounting means extending over and being attached to both of the electrodes and defining fixed mounting at spaced points.
- said dielectric core and said electrically conductive electrodes are integrally bonded throughout their interface, said core being formed of a silicone elastomer, each of said conductive electrodes being formed of a silicone elastomer and having electrically conductive particles distributed throughout the rubber to define a conductive plate.
- the capacitance sensing element of claim 2 wherein the core is a solid flexible element having a dielectric constant of essentially 1.1 to 25, an elastic modulus of essentially l to 1,000,000 pounds per square inch and a'thickness of essentially 0.0001 inch to 0.1000 inch.
- the capacitance sensing element of claim 12 wherein the core thickness is constant and between 0.0003 and 0.0200 inch thick.
- a pressure sensitive capacitance sensing element comprising a sheet-like core formed of a flexible solid dielectric material, a plurality of electrically conductive and flexible solid electrodes interconnected with said core layer to define a capacitor diaphragm, a fixed mounting means connected to said electrodes and rigidly supporting of spaced portions of the diaphragm and with the diaphragm elastically moving with respect to the fixed mounting and correspondingly deforming the capacitor with an increased conductive area of the electrodes with respect to said mounting and a decreased dielectric layer thickness to thereby provide a change in the capacitance of the element in response to a differential fluid force applied to opposite sides of the diaphragm.
- the pressure sensitive capacitance sensing element of claim 19 wherein the mounting means includes a pair of ring-like members secured in clamping relationship to the peripheral edge portion of the diaphragm, wherein at least one ring-like member is of an insulating material and contact means in each of said ring-like members firmly abutting the adjacent electrode.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Fluid Pressure (AREA)
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US00361813A US3814998A (en) | 1973-05-18 | 1973-05-18 | Pressure sensitive capacitance sensing element |
CA196,605A CA1036832A (fr) | 1973-05-18 | 1974-04-02 | Element de detection de capacite sensible a la pression |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US00361813A US3814998A (en) | 1973-05-18 | 1973-05-18 | Pressure sensitive capacitance sensing element |
Publications (1)
Publication Number | Publication Date |
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US3814998A true US3814998A (en) | 1974-06-04 |
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ID=23423544
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US00361813A Expired - Lifetime US3814998A (en) | 1973-05-18 | 1973-05-18 | Pressure sensitive capacitance sensing element |
Country Status (2)
Country | Link |
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US (1) | US3814998A (fr) |
CA (1) | CA1036832A (fr) |
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3962921A (en) * | 1972-02-04 | 1976-06-15 | The Garrett Corporation | Compensated pressure transducer |
US4158217A (en) * | 1976-12-02 | 1979-06-12 | Kaylico Corporation | Capacitive pressure transducer with improved electrode |
FR2442438A1 (fr) * | 1978-11-24 | 1980-06-20 | Vaisala Oy | Manometre |
US4234361A (en) * | 1979-07-05 | 1980-11-18 | Wisconsin Alumni Research Foundation | Process for producing an electrostatically deformable thin silicon membranes utilizing a two-stage diffusion step to form an etchant resistant layer |
US5090246A (en) * | 1990-09-19 | 1992-02-25 | Johnson Service Corp. | Elastomer type low pressure sensor |
US5542300A (en) * | 1994-01-24 | 1996-08-06 | Setra Systems, Inc. | Low cost, center-mounted capacitive pressure sensor |
US20080066564A1 (en) * | 2006-09-15 | 2008-03-20 | Tokai Rubber Industries, Ltd. | Deformation sensor |
US20080282806A1 (en) * | 2007-05-16 | 2008-11-20 | Rosemount Inc. | Electrostatic pressure sensor with porous dielectric diaphragm |
US20090015270A1 (en) * | 2007-07-12 | 2009-01-15 | Tokai Rubber Industries, Ltd. | Electrostatic capacity-type sensor |
US20120186594A1 (en) * | 2009-09-18 | 2012-07-26 | Minilogic Device Corporation Ltd. | Electronic smoke |
US8303897B2 (en) | 2011-02-28 | 2012-11-06 | Colla Jeannine O | Capacitive sensor for organic chemicals comprising an elastomer and high dielectric materials with titanate |
US20120282113A1 (en) * | 2011-05-05 | 2012-11-08 | Anex Deon S | Gel coupling for electrokinetic delivery systems |
US20180173250A1 (en) * | 2016-12-21 | 2018-06-21 | Fimcim S.P.A. | Assembly installable in an air conditioning and/or heating system, air conditioning and/or heating system comprising the assembly and method of controlling the assembly |
US10420374B2 (en) | 2009-09-18 | 2019-09-24 | Altria Client Services Llc | Electronic smoke apparatus |
EP2375979B1 (fr) * | 2009-01-13 | 2019-12-11 | Urgo Recherche Innovation et Développement | Systeme de mesure de pression d'interface |
Citations (4)
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---|---|---|---|---|
US2165738A (en) * | 1931-09-16 | 1939-07-11 | Hollandsche Draad En Kabelfabriek Nv | Electric conducting element |
US3177967A (en) * | 1962-09-05 | 1965-04-13 | Louis A Wilson | Taxi control systems |
US3582728A (en) * | 1969-03-06 | 1971-06-01 | Johnson Service Co | Capacitance humidity sensing element |
US3678378A (en) * | 1968-04-04 | 1972-07-18 | Nat Res Dev | Capacitors |
-
1973
- 1973-05-18 US US00361813A patent/US3814998A/en not_active Expired - Lifetime
-
1974
- 1974-04-02 CA CA196,605A patent/CA1036832A/fr not_active Expired
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2165738A (en) * | 1931-09-16 | 1939-07-11 | Hollandsche Draad En Kabelfabriek Nv | Electric conducting element |
US3177967A (en) * | 1962-09-05 | 1965-04-13 | Louis A Wilson | Taxi control systems |
US3678378A (en) * | 1968-04-04 | 1972-07-18 | Nat Res Dev | Capacitors |
US3582728A (en) * | 1969-03-06 | 1971-06-01 | Johnson Service Co | Capacitance humidity sensing element |
Non-Patent Citations (1)
Title |
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Condensed Chemical Dictionary, Sixth Edition, Reinhold N.Y., 1961, p. 1019. * |
Cited By (26)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3962921A (en) * | 1972-02-04 | 1976-06-15 | The Garrett Corporation | Compensated pressure transducer |
US4158217A (en) * | 1976-12-02 | 1979-06-12 | Kaylico Corporation | Capacitive pressure transducer with improved electrode |
FR2442438A1 (fr) * | 1978-11-24 | 1980-06-20 | Vaisala Oy | Manometre |
US4234361A (en) * | 1979-07-05 | 1980-11-18 | Wisconsin Alumni Research Foundation | Process for producing an electrostatically deformable thin silicon membranes utilizing a two-stage diffusion step to form an etchant resistant layer |
US5090246A (en) * | 1990-09-19 | 1992-02-25 | Johnson Service Corp. | Elastomer type low pressure sensor |
EP0476309A2 (fr) * | 1990-09-19 | 1992-03-25 | Johnson Service Company | Transducteur capacitif élastomérique pour basses pressions |
EP0476309A3 (en) * | 1990-09-19 | 1993-03-17 | Johnson Service Company | Capacitance elastomeric low pressure sensor |
US5542300A (en) * | 1994-01-24 | 1996-08-06 | Setra Systems, Inc. | Low cost, center-mounted capacitive pressure sensor |
US20080066564A1 (en) * | 2006-09-15 | 2008-03-20 | Tokai Rubber Industries, Ltd. | Deformation sensor |
US7703333B2 (en) * | 2006-09-15 | 2010-04-27 | Tokai Rubber Industries, Ltd. | Deformation sensor |
US20080282806A1 (en) * | 2007-05-16 | 2008-11-20 | Rosemount Inc. | Electrostatic pressure sensor with porous dielectric diaphragm |
US8079269B2 (en) * | 2007-05-16 | 2011-12-20 | Rosemount Inc. | Electrostatic pressure sensor with porous dielectric diaphragm |
EP2015043A3 (fr) * | 2007-07-12 | 2009-11-25 | Tokai Rubber Industries, Ltd. | Capteur à capacité électrostatique |
US20090015270A1 (en) * | 2007-07-12 | 2009-01-15 | Tokai Rubber Industries, Ltd. | Electrostatic capacity-type sensor |
JP2009020006A (ja) * | 2007-07-12 | 2009-01-29 | Tokai Rubber Ind Ltd | 静電容量型センサ |
US8451011B2 (en) | 2007-07-12 | 2013-05-28 | Tokai Rubber Industries, Ltd. | Electrostatic capacity-type sensor |
EP2375979B1 (fr) * | 2009-01-13 | 2019-12-11 | Urgo Recherche Innovation et Développement | Systeme de mesure de pression d'interface |
US10420374B2 (en) | 2009-09-18 | 2019-09-24 | Altria Client Services Llc | Electronic smoke apparatus |
US20120186594A1 (en) * | 2009-09-18 | 2012-07-26 | Minilogic Device Corporation Ltd. | Electronic smoke |
US11974610B2 (en) | 2009-09-18 | 2024-05-07 | Altria Client Services Llc | Electronic smoke apparatus |
US9072321B2 (en) * | 2009-09-18 | 2015-07-07 | Minilogic Device Corporation Ltd. | Electronic smoke |
US8303897B2 (en) | 2011-02-28 | 2012-11-06 | Colla Jeannine O | Capacitive sensor for organic chemicals comprising an elastomer and high dielectric materials with titanate |
US8979511B2 (en) * | 2011-05-05 | 2015-03-17 | Eksigent Technologies, Llc | Gel coupling diaphragm for electrokinetic delivery systems |
US20120282113A1 (en) * | 2011-05-05 | 2012-11-08 | Anex Deon S | Gel coupling for electrokinetic delivery systems |
US20180173250A1 (en) * | 2016-12-21 | 2018-06-21 | Fimcim S.P.A. | Assembly installable in an air conditioning and/or heating system, air conditioning and/or heating system comprising the assembly and method of controlling the assembly |
US10605638B2 (en) * | 2016-12-21 | 2020-03-31 | Fimcim S.P.A. | Assembly installable in an air conditioning and/or heating system, air conditioning and/or heating system comprising the assembly and method of controlling the assembly |
Also Published As
Publication number | Publication date |
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CA1036832A (fr) | 1978-08-22 |
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Owner name: JOHNSON CONTROLS INTERNATIONAL, INC., 229 SOUTH ST Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:JOHNSON SERVICE COMPANY, A CORP. OF DE.;REEL/FRAME:003962/0639 Effective date: 19820302 |
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