GB2064125A - Position indicating apparatus - Google Patents

Position indicating apparatus Download PDF

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Publication number
GB2064125A
GB2064125A GB7940902A GB7940902A GB2064125A GB 2064125 A GB2064125 A GB 2064125A GB 7940902 A GB7940902 A GB 7940902A GB 7940902 A GB7940902 A GB 7940902A GB 2064125 A GB2064125 A GB 2064125A
Authority
GB
United Kingdom
Prior art keywords
coils
position indicating
secondary coil
metallic member
inductance
Prior art date
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.)
Withdrawn
Application number
GB7940902A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
UK Atomic Energy Authority
Original Assignee
UK Atomic Energy Authority
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 UK Atomic Energy Authority filed Critical UK Atomic Energy Authority
Priority to GB7940902A priority Critical patent/GB2064125A/en
Publication of GB2064125A publication Critical patent/GB2064125A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/26—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G01D5/20—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature
    • G01D5/204—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the mutual induction between two or more coils
    • G01D5/2053—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the mutual induction between two or more coils by a movable non-ferromagnetic conductive element
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
    • G01F1/20—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow
    • G01F1/22—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow by variable-area meters, e.g. rotameters
    • G01F1/24—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow by variable-area meters, e.g. rotameters with magnetic or electric coupling to the indicating device

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Power Engineering (AREA)
  • Thermal Sciences (AREA)
  • Level Indicators Using A Float (AREA)

Abstract

A position indicating instrument comprising elongate primary (P) and secondary (S) mutual inductance coils in which the inductance of the secondary varies linearly over its length, and a metabolic member F, associated with the position to be indicated, displaceable along the secondary coil to cause a local perturbation in the magnetic field. The coils may be helical and with the number of turns per unit length varying along the length of the secondary, which is a pair of coils in opposite sense connected differentially. The coils may be of planar form, the primary being rectangular and the secondary triangular or the secondary may have a pair of opposed triangular coils. <IMAGE>

Description

SPECIFICATION Position indicating apparatus This invention relates to position indicating apparatus and is primarily directed to such apparatus for analogous indication of liquid level.
According to the invention position indicating apparatus comprises elongate primary and secondary mutual inductance coils arranged so that inductance in the secondary coil is linearly variable over its length and wherein there is a metallic member associated with the position to be indicated and displaceable along the secondary coil to cause a local perturbation in the magnetic field. In such an indicator the induced voltage in the secondary coils is analogous to the position of the metallic member.
The coils may be helically wound the secondary coil having a varying number of turns over its length to produce a linearly variable inductance or the coils may be of substantially planar form the secondary coil being triangular to produce a linearly variable inductance in the secondary coil.
The apparatus may include a pair of helically wound secondary coils wound in opposite sense and connected differentially so that the standing induced voltage is eliminated. Alternatively the apparatus may include a pair of opposed triangular secondary coils connected differentially so that the standing induced voltage is eliminated.
The invention finds application in analogue measurement of liquid level, the metallic member constituting a float.
Apparatus embodying the invention is described by way of example with reference to the accompanying diagrammatic drawings wherein, Figure 1 is a circuit diagram, Figure 2 is an alternative circuit diagram, Figure 3 is a voltage output/displacement curve, and Figure 4 is a circuit diagram of an alternative apparatus.
The apparatus indicated diagrammatically in Figure 1 comprises primary and secondary mutual inductance coils P and S, and F indicates a metallic member which is displaceable parallel to the coils. P is a coil of regular helical winding connected to an alternating current source whilst S is a helically wound coil having a varying number of turns/unit length so that induction is linearly variable over its length. When the metallic member F is displaced parallel to the coils it creates a local perturbation in the magnetic field the resultant change in the induced voltage being dependent on the position of the metallic member.
The change in the induced voltage is superimposed on a standing voltage which can be eliminated by utilising two secondary coils wound in opposite senses and differentially connected as shown in Figure 2. In such an apparatus the output/displacement characteristic will change in opposite sense about a central position for the metallic member as indicated in Figure 3.
In an alternative apparatus shown diagrammatically in Figure 4 the mutual inductance coils are of substantially planar form.
The primary is of elongate rectangular form whilst the differentially connected secondary coils are of elongate triangular form.
It is envisaged that the apparatus can be utilised to measure rate of flow of a liquid by measuring the position of a float supported by fluid flow in a vertical duct of variable cross section.
1. Position indicating apparatus comprising elongate primary and secondary mutual inductance coils arranged so that inductance in the secondary coil is linearly variable over its length and wherein there is a metallic member associated with the position to be indicated and displaceable along the secondary coil to cause a local perturbation in the magnetic field.
2. Position indicating apparatus according to claim 1 wherein the coils are helically wound the secondary coil having a varying number of turns over its length to produce a linearly variable inductance.
3. Position indicating apparatus according to claim 1 wherein the coils are of substantially planar form the secondary coil being triangular to produce a linearly variable inductance in the secondary coil.
4. Position indicating apparatus according to claim 2 wherein there is a pair of helically wound secondary coils wound in opposite sense and connected differentially so that the standing induced voltage is eliminated.
5. Position indicating apparatus according to claim 3 wherein there is a pair of opposed triangular secondary coils connected differentially so that the standing induced voltage is eliminated.
6. Position indicating apparatus substantially as hereinbefore described with reference to any one of Figures 1, 2 and 4 of the accompanying drawings.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Position indicating apparatus This invention relates to position indicating apparatus and is primarily directed to such apparatus for analogous indication of liquid level. According to the invention position indicating apparatus comprises elongate primary and secondary mutual inductance coils arranged so that inductance in the secondary coil is linearly variable over its length and wherein there is a metallic member associated with the position to be indicated and displaceable along the secondary coil to cause a local perturbation in the magnetic field. In such an indicator the induced voltage in the secondary coils is analogous to the position of the metallic member. The coils may be helically wound the secondary coil having a varying number of turns over its length to produce a linearly variable inductance or the coils may be of substantially planar form the secondary coil being triangular to produce a linearly variable inductance in the secondary coil. The apparatus may include a pair of helically wound secondary coils wound in opposite sense and connected differentially so that the standing induced voltage is eliminated. Alternatively the apparatus may include a pair of opposed triangular secondary coils connected differentially so that the standing induced voltage is eliminated. The invention finds application in analogue measurement of liquid level, the metallic member constituting a float. Apparatus embodying the invention is described by way of example with reference to the accompanying diagrammatic drawings wherein, Figure 1 is a circuit diagram, Figure 2 is an alternative circuit diagram, Figure 3 is a voltage output/displacement curve, and Figure 4 is a circuit diagram of an alternative apparatus. The apparatus indicated diagrammatically in Figure 1 comprises primary and secondary mutual inductance coils P and S, and F indicates a metallic member which is displaceable parallel to the coils. P is a coil of regular helical winding connected to an alternating current source whilst S is a helically wound coil having a varying number of turns/unit length so that induction is linearly variable over its length. When the metallic member F is displaced parallel to the coils it creates a local perturbation in the magnetic field the resultant change in the induced voltage being dependent on the position of the metallic member. The change in the induced voltage is superimposed on a standing voltage which can be eliminated by utilising two secondary coils wound in opposite senses and differentially connected as shown in Figure 2. In such an apparatus the output/displacement characteristic will change in opposite sense about a central position for the metallic member as indicated in Figure 3. In an alternative apparatus shown diagrammatically in Figure 4 the mutual inductance coils are of substantially planar form. The primary is of elongate rectangular form whilst the differentially connected secondary coils are of elongate triangular form. It is envisaged that the apparatus can be utilised to measure rate of flow of a liquid by measuring the position of a float supported by fluid flow in a vertical duct of variable cross section. CLAIMS
1. Position indicating apparatus comprising elongate primary and secondary mutual inductance coils arranged so that inductance in the secondary coil is linearly variable over its length and wherein there is a metallic member associated with the position to be indicated and displaceable along the secondary coil to cause a local perturbation in the magnetic field.
2. Position indicating apparatus according to claim 1 wherein the coils are helically wound the secondary coil having a varying number of turns over its length to produce a linearly variable inductance.
3. Position indicating apparatus according to claim 1 wherein the coils are of substantially planar form the secondary coil being triangular to produce a linearly variable inductance in the secondary coil.
4. Position indicating apparatus according to claim 2 wherein there is a pair of helically wound secondary coils wound in opposite sense and connected differentially so that the standing induced voltage is eliminated.
5. Position indicating apparatus according to claim 3 wherein there is a pair of opposed triangular secondary coils connected differentially so that the standing induced voltage is eliminated.
6. Position indicating apparatus substantially as hereinbefore described with reference to any one of Figures 1, 2 and 4 of the accompanying drawings.
GB7940902A 1979-11-27 1979-11-27 Position indicating apparatus Withdrawn GB2064125A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB7940902A GB2064125A (en) 1979-11-27 1979-11-27 Position indicating apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB7940902A GB2064125A (en) 1979-11-27 1979-11-27 Position indicating apparatus

Publications (1)

Publication Number Publication Date
GB2064125A true GB2064125A (en) 1981-06-10

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ID=10509434

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7940902A Withdrawn GB2064125A (en) 1979-11-27 1979-11-27 Position indicating apparatus

Country Status (1)

Country Link
GB (1) GB2064125A (en)

Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2167563A (en) * 1984-10-19 1986-05-29 Kollmorgen Tech Corp Position and speed sensors
US4697144A (en) * 1984-04-19 1987-09-29 Verify Electronics Limited Position sensing apparatus
FR2642253A1 (en) * 1988-11-28 1990-07-27 Mo N Proizv ULTRASONIC TRANSDUCER FOR VISUALIZATION OF DEFECTS
FR2716713A1 (en) * 1994-02-28 1995-09-01 Bosch Gmbh Robert Installation for measuring a stroke or an angle.
WO1995031696A1 (en) * 1994-05-14 1995-11-23 Scientific Generics Limited Position encoder
US5841274A (en) * 1997-01-29 1998-11-24 Mitutoyo Corporation Induced current absolute position transducer using a code-track-type scale and read head
US5886519A (en) * 1997-01-29 1999-03-23 Mitutoyo Corporation Multi-scale induced current absolute position transducer
US5973494A (en) * 1996-05-13 1999-10-26 Mitutoyo Corporation Electronic caliper using a self-contained, low power inductive position transducer
US6002250A (en) * 1996-05-13 1999-12-14 Mitutoyo Corporation Electronic linear scale using a self-contained, low-power inductive position transducer
US6011389A (en) * 1995-05-16 2000-01-04 Mitutoyo Corporation Induced current position transducer having a low power electronic circuit
US6249234B1 (en) 1994-05-14 2001-06-19 Absolute Sensors Limited Position detector
US6304014B1 (en) 1997-10-02 2001-10-16 Synaptics (Uk) Limited Motor control system
US6522128B1 (en) 1997-10-15 2003-02-18 Synaptics (Uk) Limited Position sensor having compact arrangement of coils
US6534970B1 (en) 1998-05-22 2003-03-18 Synaptics (Uk) Limited Rotary position sensor and transducer for use therein
US6705511B1 (en) 1997-05-28 2004-03-16 Synaptics (Uk) Limited Transducer and method of manufacture
US6788221B1 (en) 1996-06-28 2004-09-07 Synaptics (Uk) Limited Signal processing apparatus and method
US7117732B2 (en) * 2003-12-01 2006-10-10 Societe Bic Fuel gauge for fuel cartridges
FR2885687A1 (en) * 2005-05-11 2006-11-17 Electricfil Automotive Soc Par Vehicle chassis height determining device for e.g. optimizing road ability, has sensor with two parts mounted in contactless manner so that change of position of one part relative to other influences magnetic or electromagnetic quantity
US7812268B2 (en) 2003-08-26 2010-10-12 Synaptics (Uk) Limited Digitizer system
US7907130B2 (en) 2002-06-05 2011-03-15 Synaptics (Uk) Limited Signal transfer method and apparatus
US8243033B2 (en) 2001-05-21 2012-08-14 Synaptics (Uk) Limited Position sensor
US8286464B2 (en) 2006-12-22 2012-10-16 Societe Bic Sensing device and methods related thereto
US8570028B2 (en) 2007-05-10 2013-10-29 Cambridge Integrated Circuits Limited Transducer for a position sensor
US9410791B2 (en) 2010-12-24 2016-08-09 Cambridge Integrated Circuits Limited Position sensing transducer
US9470505B2 (en) 2012-06-13 2016-10-18 Cambridge Integrated Circuits Limited Position sensing transducer

Cited By (35)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4697144A (en) * 1984-04-19 1987-09-29 Verify Electronics Limited Position sensing apparatus
US4737698A (en) * 1984-10-19 1988-04-12 Kollmorgan Technologies Corporation Position and speed sensors
GB2167563B (en) * 1984-10-19 1989-03-01 Kollmorgen Tech Corp Position and speed sensors
US4853604A (en) * 1984-10-19 1989-08-01 Kollmorgen Technologies Corporation Position and speed sensors
GB2167563A (en) * 1984-10-19 1986-05-29 Kollmorgen Tech Corp Position and speed sensors
FR2642253A1 (en) * 1988-11-28 1990-07-27 Mo N Proizv ULTRASONIC TRANSDUCER FOR VISUALIZATION OF DEFECTS
FR2716713A1 (en) * 1994-02-28 1995-09-01 Bosch Gmbh Robert Installation for measuring a stroke or an angle.
WO1995031696A1 (en) * 1994-05-14 1995-11-23 Scientific Generics Limited Position encoder
US5815091A (en) * 1994-05-14 1998-09-29 Scientific Generics Limited Position encoder
US6489899B1 (en) 1994-05-14 2002-12-03 Synaptics (Uk) Limited Position detector
US6249234B1 (en) 1994-05-14 2001-06-19 Absolute Sensors Limited Position detector
US6011389A (en) * 1995-05-16 2000-01-04 Mitutoyo Corporation Induced current position transducer having a low power electronic circuit
DE19719905B9 (en) * 1996-05-13 2006-06-08 Mitutoyo Corp., Kawasaki Electronic caliper with a low-power inductive position transducer
US5973494A (en) * 1996-05-13 1999-10-26 Mitutoyo Corporation Electronic caliper using a self-contained, low power inductive position transducer
US6002250A (en) * 1996-05-13 1999-12-14 Mitutoyo Corporation Electronic linear scale using a self-contained, low-power inductive position transducer
DE19719905B4 (en) * 1996-05-13 2006-02-23 Mitutoyo Corp., Kawasaki Electronic caliper with a low-power inductive position transducer
US6788221B1 (en) 1996-06-28 2004-09-07 Synaptics (Uk) Limited Signal processing apparatus and method
US6980134B2 (en) 1996-06-28 2005-12-27 Synaptics (Uk) Limited Signal processing apparatus and method
US5841274A (en) * 1997-01-29 1998-11-24 Mitutoyo Corporation Induced current absolute position transducer using a code-track-type scale and read head
US6054851A (en) * 1997-01-29 2000-04-25 Mitutoyo Corporation Induced current absolute position transducer method using a code-track-type scale and read head
US5886519A (en) * 1997-01-29 1999-03-23 Mitutoyo Corporation Multi-scale induced current absolute position transducer
DE19803249B4 (en) * 1997-01-29 2015-02-26 Mitutoyo Corp. Induced current absolute position transducer equipped with a code track scale and read head
US6705511B1 (en) 1997-05-28 2004-03-16 Synaptics (Uk) Limited Transducer and method of manufacture
US6304014B1 (en) 1997-10-02 2001-10-16 Synaptics (Uk) Limited Motor control system
US6522128B1 (en) 1997-10-15 2003-02-18 Synaptics (Uk) Limited Position sensor having compact arrangement of coils
US6534970B1 (en) 1998-05-22 2003-03-18 Synaptics (Uk) Limited Rotary position sensor and transducer for use therein
US8243033B2 (en) 2001-05-21 2012-08-14 Synaptics (Uk) Limited Position sensor
US7907130B2 (en) 2002-06-05 2011-03-15 Synaptics (Uk) Limited Signal transfer method and apparatus
US7812268B2 (en) 2003-08-26 2010-10-12 Synaptics (Uk) Limited Digitizer system
US7117732B2 (en) * 2003-12-01 2006-10-10 Societe Bic Fuel gauge for fuel cartridges
FR2885687A1 (en) * 2005-05-11 2006-11-17 Electricfil Automotive Soc Par Vehicle chassis height determining device for e.g. optimizing road ability, has sensor with two parts mounted in contactless manner so that change of position of one part relative to other influences magnetic or electromagnetic quantity
US8286464B2 (en) 2006-12-22 2012-10-16 Societe Bic Sensing device and methods related thereto
US8570028B2 (en) 2007-05-10 2013-10-29 Cambridge Integrated Circuits Limited Transducer for a position sensor
US9410791B2 (en) 2010-12-24 2016-08-09 Cambridge Integrated Circuits Limited Position sensing transducer
US9470505B2 (en) 2012-06-13 2016-10-18 Cambridge Integrated Circuits Limited Position sensing transducer

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