公开(公告)号：WO1991010888A1

公开(公告)日：1991-07-25

申请号：PCT/US1991000206

申请日：1991-01-10

Applicant: SETRA SYSTEMS, INC.

Inventor： SETRA SYSTEMS, INC. ,  LEE, Shih-Ying

IPC: G01L07/08

CPC classification number: G01L9/0072

Abstract: A flush-mounted sensor measures the pressure of a fluid within a hollow conduit (26). A sensor head (18) edge-mounts an isolating diaphragm (12) responsive to the pressure of the fluid. The isolating diaphragm (12) has a small diameter, typically less than 1/4 inch, is adjacent the fluid in the conduit (26) to reduce the dead volume of fluid adjacent the diaphragm (12), formed of a material that is compatible with the fluid. A drive rod (14) mechanically couples the isolating diaphragm (12) to a second diaphragm (16) of a variable capacitor assembly (17). The second diaphragm (16) is also edge-mounted and produces a counterforce acting on the side of the isolating diaphragm (12) opposite the side adjacent the fluid. The force of the fluid pressure acting on the isolating diaphragm (12) is transmitted by the drive rod (14) to the second diaphragm (16) where changes in the capacitance correspond to changes in the pressure. In another form the isolating diaphragm is formed as a thin, non-circular portion of the conduit wall.

公开(公告)号：WO1995020230A1

公开(公告)日：1995-07-27

申请号：PCT/US1995000851

申请日：1995-01-20

Applicant: SETRA SYSTEMS, INC.

Inventor： SETRA SYSTEMS, INC. ,  LEE, Shih-Ying

IPC: H01G07/00

CPC classification number: G01L9/0072

Abstract: A variable capacitance type pressure sensor (10) with excellent manufacturability center-mounts an electrode (20) on an edge-mounted diaphragm (16) using a metal-glass-metal subassembly (18). An inner metal post (28) of the assembly is welded to the diaphragm (16). A solder or flowable cement (36) secures the electrode (20) to an outer metal collar (32) of the assembly (18) with the initial diaphragm-to-electrode spacing (38) set by a temporary shim (40). The position of the glass (30) and the physical lengths of the metallic members (28, 32) of the assembly are adjusted to provide self-compensation for temperature variations.

Abstract translation: 具有优异制造性的可变电容型压力传感器（10）使用金属玻璃 - 金属子组件（18）将电极（20）中心安装在边缘安装的隔膜（16）上。 组件的内金属柱（28）焊接到隔膜（16）。 焊料或可流动的水泥（36）将电极（20）固定到组件（18）的外部金属套环（32）上，其中由临时垫片（40）设定的初始隔膜 - 电极间隔（38）。 调整玻璃（30）的位置和组件的金属构件（28,32）的物理长度，以便为温度变化提供自我补偿。

公开(公告)号：WO1995006236A1

公开(公告)日：1995-03-02

申请号：PCT/US1994009302

申请日：1994-08-12

Applicant: SETRA SYSTEMS, INC.

Inventor： SETRA SYSTEMS, INC. ,  LEE, Shih-Ying

IPC: G01L07/08

CPC classification number: G01L9/0072

Abstract: A capacitive pressure sensor (10) includes a conductive diaphragm (20) positioned between two pneumatically separate chambers (60, 64). The diaphragm is supported at its periphery by a concave base member (30). An electrode assembly (40) establishes a substantially planar conductive surface (42a) opposite to, and spaced apart by a nominal gap from, the conductive diaphragm. The electrode assembly includes the conductive surface and a single support element (44) secured to, and extending through the base member. A glass dielectric (46) fixes the support element to a collar (48) which may be welded, brazed, or soldered to the base member. The glass dielectric provides both mechanical support and high quality electric insulation between the electrode and the housing. By prefabricating the electrode support element with the collar and securing the collar to the housing after the dielectric has cured, problems associated with thermal expansion are avoided and the dimension of the nominal gap may be precisely controlled at low cost.

Abstract translation: 电容式压力传感器（10）包括位于两个气动分离室（60,64）之间的导电隔膜（20）。 隔膜在其周边由凹入的基底构件（30）支撑。 电极组件（40）建立与导电隔膜相对且间隔开标称间隙的基本平坦的导电表面（42a）。 电极组件包括导电表面和固定到基底构件并延伸通过基底构件的单个支撑元件（44）。 玻璃电介质（46）将支撑元件固定到可以焊接，钎焊或焊接到基底构件的套环（48）上。 玻璃电介质在电极和壳体之间提供机械支撑和高质量的电绝缘。 通过在电介质固化之后预制电极支撑元件和套圈并将套环固定到壳体，避免了与热膨胀相关的问题，并且可以以低成本精确地控制标称间隙的尺寸。

公开(公告)号：WO1988007182A1

公开(公告)日：1988-09-22

申请号：PCT/US1988000704

申请日：1988-02-26

Applicant: SETRA SYSTEMS, INC.

Inventor： SETRA SYSTEMS, INC. ,  LEE, Shih-Ying

IPC: G01L01/14

CPC classification number: G01G21/24 ,  G01G7/06 ,  G01L1/142

Abstract: A compact force transducer (10) has at least one flexible beam (16, 18) mounted at one or both its ends to a force summing member (12, 14) or members. The force-to-be-measured is applied to the force summing member (12, 14) along a first axis (22) generally transverse to the beams to deform the beam elastically, without overstressing, through a displacement d. A sensor member (28, 30) carries a conductive surface (38) and is coupled to the beam member. In a parallelogram form, there are a parallel pair of beam members (16, 18) extending between two force summing members (12, 14) and a sensor member (28, 30) is secured to each beam member (16, 18) at or near its point of inflection. One sensor member (30) includes multiple arms (36, 36) that sandwich the other sensor member (28) to produce a linear, push-pull mode of operation. In alow cost cantilevered beam form, the sensor (28') is coupled to the beam (16') at the force summing member (14') in a parallel, spaced relationship. In a hybrid push-pull form, the transducer uses a two beam parallelogram construction with cantilevered sensors (28'', 30'') (1) coupled rigidly to each beam (16'', 18'') adjacent one force summing member (12'', 14'') with a hinge coupling (16''a, 18''a) between the beam and this one force summing member, and (2) extending generally in a parallel spaced relationship with respect to an associated one of the beams (16'', 18'').

公开(公告)号：WO1996021845A1

公开(公告)日：1996-07-18

申请号：PCT/US1996000333

申请日：1996-01-11

Applicant: SETRA SYSTEMS, INC.

Inventor： SETRA SYSTEMS, INC. ,  BRIEFER, Dennis, K. ,  BATISTA, Anthony, T.

IPC: G01F09/00

CPC classification number: G01N9/26 ,  G01F23/18

Abstract: An apparatus for measuring the pressure of a liquid column (36) enclosed within a pressurized tank or cell (37), and for deriving the height and/or density of the liquid column based on the measured pressure. The apparatus includes a first pressure sensor (38) for differentially measuring the pressure within the cell relative to a reference pressure at a first height (H1), and further includes a second pressure sensor (39) for differentially measuring the pressure within the cell relative to a reference pressure at a second height (H2). A feed back network (48) is operative to match the reference pressure to the pressure within the cell at one of the first and second heights. The feedback network ensures that the sensor detecting the one region is maintained at a zero or null differential pressure condition, enabling the use of a small dynamic range sensor.

Abstract translation: 一种用于测量包围在加压罐或电池（37）内的液柱（36）的压力的装置，以及用于根据所测量的压力导出液柱的高度和/或密度。 该设备包括：第一压力传感器（38），用于相对于在第一高度（H1）处的参考压力差异地测量单元内的压力，并且还包括第二压力传感器（39），用于差分地测量单元内的压力相对 到第二高度（H2）的参考压力。 反馈网络（48）可操作以将参考压力与第一和第二高度中的一个处的单元内的压力相匹配。 反馈网络确保检测一个区域的传感器保持在零或零差压条件下，使得能够使用小的动态范围传感器。

公开(公告)号：WO1991007645A1

公开(公告)日：1991-05-30

申请号：PCT/US1990006393

申请日：1990-11-05

Applicant: SETRA SYSTEMS, INC.

Inventor： SETRA SYSTEMS, INC. ,  LEE, Shih-Ying

IPC: G01L09/04

CPC classification number: G01L9/0004 ,  A61M2205/3331 ,  G01L9/0002 ,  G01L9/0005

Abstract: A transducer measures the pressure of a fluid within a hollow conduit, typically one with a circular cross-section, having a central region that is deformed to a non-circular cross-section. This non-circular portion of the conduit displaces radially and repeatably without hysteresis in response to the pressure of the fluid in the conduit in a manner that corresponds to the pressure. A variable capacitor assembly (26), or a set of strain gauges (A, B, C, D) mounted on the exterior of the non-circular portion, produce an electrical signal proportional to the radial displacement or to the strain, respectively. In one capacitive form (26) a pair of electrodes (24) are mounted on opposite sides of the non-circular portion formed as free end portions of metallic sheet members with a central channel. In another capacitive form (26') electrodes (24') are mounted at one or both ends of lever arms which in turn are coupled to the non-circular portion with a set of flexure plates (34, 36) to produce a mechanical amplification of the radial displacement.

公开(公告)号：WO1996041141A1

公开(公告)日：1996-12-19

申请号：PCT/US1996008415

申请日：1996-06-03

Applicant: SETRA SYSTEMS, INC.

Inventor： SETRA SYSTEMS, INC. ,  BRIEFER, Dennis, K. ,  PINTO, Gino, A.

IPC: G01L09/10

CPC classification number: G01L9/007 ,  G01D5/202 ,  G01L1/14

Abstract: A differential pressure transducer includes a pair of interior chambers (12, 14) separated by supported, nominally planar electrically conductive diaphragm (16). A magnetic assembly is positioned on at least one chamber wall opposite an electrical conductor.

Abstract translation: 差压传感器包括由支撑的标称平面的导电隔膜（16）分开的一对内室（12,14）。 磁性组件位于与电导体相对的至少一个室壁上。

公开(公告)号：WO1992002790A1

公开(公告)日：1992-02-20

申请号：PCT/US1991004631

申请日：1991-06-28

Applicant: SETRA SYSTEMS, INC.

Inventor： SETRA SYSTEMS, INC. ,  BRIEFER, Dennis, K.

IPC: G01G03/14

CPC classification number: G01G3/12 ,  G01G7/06

Abstract: An instrument (20) includes multiple sensing elements (6a, 6b, 6c, 6d) of the variable-capacitance type. The sensing elements are placed by a switching network (22) into a single capacitance sensing circuit (8); and those elements which are not active in the circuit at a given time are switched by another or the same switching network into a ground shunt (24). Preferably, all switching occurs at a ground state, and the sensing circuit briefly samples a sensing signal between successive switching operations, so that the sensed signal is uncorrupted by stray capacitance effects. The switching is effected at a rate, in relation to the expected vibrational spectrum of the sensor system, to determine a set of readings which are essentially equivalent to a set of simultaneous capacitance measurements of the plural sensing elements. A preferred system is a wight sensing system employing three or four load cells to support a scale platform.

公开(公告)号：WO1990004153A1

公开(公告)日：1990-04-19

申请号：PCT/US1989002547

申请日：1989-06-12

Applicant: SETRA SYSTEMS, INC.

Inventor： SETRA SYSTEMS, INC. ,  LI, Da, Ke

IPC: G01G03/14

CPC classification number: G01G23/00 ,  G01G7/06

Abstract: The relative humidity of air present within a housing of a scale (10), utilizing a capacitive transducer (16) mounted at the interior of the housing, is controlled by a combination of (i) a mechanical partial seal (34) of the housing which resists a flow of moisture through the seal, and (ii) a supply (42) of a desiccant located within the housing which both absorbs and desorbs moisture from the air. The partial seal (34) is located at an opening (18) in the housing for a shaft (20) mounting a weighing pan (22) external to the housing. The desiccant (42) is silica gel. The values for the flow resistance and desiccant supply produce a very slow change over time, typically several years. The relative humidity within the housing varies within +5 % of a steady state value despite much larger variations in the temperature and humidity of the air surrounding the housing.

公开(公告)号：WO1990002444A1

公开(公告)日：1990-03-08

申请号：PCT/US1989003529

申请日：1989-08-17

Applicant: SETRA SYSTEMS, INC.

Inventor： SETRA SYSTEMS, INC. ,  BRIEFER, Dennis, K.

IPC: H03B05/12

CPC classification number: H03L1/02 ,  H03B5/04 ,  H03B5/1203 ,  H03B5/1231 ,  H03B2200/0034 ,  H03B2200/0048 ,  H03B2200/0056

Abstract: An oscillator (10) including a first frequency control network (12) having a series coupled inductance (L1) and sensor capacitor (CS1), a pair of cascaded capacitors (C1 and C2), and an emitter follower amplifier (18) coupled thereto. The emitter follower amplifier (18) drives a current limiter (20) and a feedback path (22), whereby the current through the emitter follower amplifier (18) is divided between the current limiter (20) and the feedback path (22) in a manner establishing an oscillatory potential in the oscillator (10), while keeping the transistor (Q1) of the emitter follower amplifier (18) substantially out of its saturation state.