US4785672A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Printed circuit capacitance electrodes
Assignee: BA BUSINESS CREDIT Inc
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Filing: 1987-06-08
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Granted: 1988-11-22
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Expires: 2007-06-08
Abstract
Abstract A magnetic flowmeter in which a fluid to be metered is conducted through a ceramic spool coaxially supported within a cylinder casing to define an inner chamber. Mounted within the chamber at opposing positions on a magnet axis perpendicular to the longitudinal flow axis of the spool are a pair of electromagnets to establish an electromagnetic field in the spool whose lines of flux are intercepted by the fluid to induce a voltage therein. Interposed between the electromagnets and the outer surface of the spool and conforming to and secured to this surface are a pair of flexible printed circuit boards which are so printed as to define capacitance metering electrodes at diametrically-opposed positions on the spool on an electrode axis at right angles to the magnet axis and at right angles to the longitudinal flow axis, whereby the voltage induced in the fluid is picked up by these electrodes to produce a signal which depends on the flow rate of the fluid.
Inventors
- 👤 Thomas L. Picone
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:47
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/56; G01F1/58; G01F1/584
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
204 words
A magnetic flowmeter comprising: A a cylindrical spool of dielectric material functioning as a flow tube for the fluid to be metered coaxially supported within a cylindrical casing to define an inner chamber; B a pair of electromagnets mounted within the inner chamber at opposing positions therein on a magnet axis perpendicular to the longitudinal flow axis of the spool to establish an electromagnetic field therein whose lines of flux are intercepted by fluid flowing therethrough to induce a voltage in the fluid; and C a pair of flexible printed circuit boards conforming to and secured to the outer surface of the spool and symmetrically disposed on either side of said magnet axis, said boards being so printed as to define capacitance metering electrodes having enlarged surfaces which extend under the electromagnets at diametrically-opposed positions on the spool on an electrode axis at right angles to the magnet axis and at right angles to the longitudinal flow axis whereby the voltage induced in the fluid is picked up by the electrodes to produce a signal which depends on the flow rate of the fluid, each electrode forming one plate of a capacitor whose dielectric is the spool and whose other plate is the fluid.
Claim 2
Dependent Claim
204 words
A magnetic flowmeter comprising: A a cylindrical spool of dielectric material functioning as a flow tube for the fluid to be metered coaxially supported within a cylindrical casing to define an inner chamber; B a pair of electromagnets mounted within the inner chamber at opposing positions therein on a magnet axis perpendicular to the longitudinal flow axis of the spool to establish an electromagnetic field therein whose lines of flux are intercepted by fluid flowing therethrough to induce a voltage in the fluid; and C a pair of flexible printed circuit boards conforming to and secured to the outer surface of the spool and symmetrically disposed on either side of said magnet axis, said boards being so printed as to define capacitance metering electrodes having enlarged surfaces which extend under the electromagnets at diametrically-opposed positions on the spool on an electrode axis at right angles to the magnet axis and at right angles to the longitudinal flow axis whereby the voltage induced in the fluid is picked up by the electrodes to produce a signal which depends on the flow rate of the fluid, each electrode forming one plate of a capacitor whose dielectric is the spool and whose other plate is the fluid.
Claim 3
Dependent Claim
26 words
A magnetic flowmeter as set forth in claim 1, wherein said casing is of soft ferromagnetic material and said electromagnets have cores integral with the casing.
Claim 4
Dependent Claim
16 words
A magnet as set forth in claim 2, wherein saddle-shaped coils are mounted on said cores.
Claim 5
Dependent Claim
22 words
A magnetic flowmeter as set forth in claim 1, wherein said spool is formed of ceramic material having a high dielectric constant.
Claim 6
Dependent Claim
17 words
A magnetic flowmeter as set forth in claim 4, wherein said dielectric constant is at least 25.
Claim 7
Dependent Claim
62 words
A magnetic flowmeter as set forth in claim 1, wherein each printed circuit board is formed by a sheet of dielectric material having said electrode printed on its front face and in contact with the outer surface of the spool, said electrode being connected by a lead going through said sheet to a contact pad on the rear face of the sheet.
Claim 8
Dependent Claim
24 words
A magnetic flowmeter as set forth in claim 6, wherein said rear face has printed thereon an outer shield which surrounds said contact pad.
Claim 9
Dependent Claim
38 words
A magnetic flowmeter as set forth in claim 7, wherein said front face has printed thereon a frame-shaped inner shield which surrounds said electrode and is connected by a lead going through the sheet to the outer shield.
Claim 10
Dependent Claim
33 words
A magnetic flowmeter as set forth in claim 8, further including a coaxial cable whose inner conductor is connected to said contact pad and whose outer conductor is connected to said outer shield.
Claim 11
Dependent Claim
16 words
A magnetic flowmeter as set forth in claim 6, wherein said sheet is formed of PTFE.
Claim 12
Dependent Claim
73 words
A magnetic flowmeter as set forth in claim 1, wherein said printed circuit board is composed of a first layer having said electrode printed on one face of a dielectric sheet and having an outer shield printed on the opposite face thereof, said first layer being laminated to a second layer having an inner shield printed on one face thereof so as to effectively surround the electrode when the layers are laminated together.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-11-22 | 1992-05-23 | 1992-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-22 | 1996-05-23 | 1996-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-22 | 2000-05-23 | 2000-11-22 | $7700.00 | Window Closed / Lapsed |