US3831069A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Miniature capacitance level detector
Assignee: Robertshaw Controls Co
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Filing: 1972-11-03
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Granted: 1974-08-20
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Expires: 1992-11-03
Abstract
Abstract A level detecting probe is constructed with a capacitor having a capacitance which varies in accordance with the level of the material under observation. The probe is self-contained in that its electrical circuitry is enclosed within a housing forming a part of the probe. In one probe embodiment for detecting the level of conductive materials the capacitor includes a conductive rod as one plate that is insulated from the conductive material which acts as the other plate. Another probe embodiment for nonconductive materials includes a conductive rod and conductive sleeve surrounding the rod and insulated therefrom as the plates of the capacitor with the non-conductive material acting as the dielectric therebetween.
Inventors
- 👤 K Merrell
- 👤 O Petersen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:37
CPC Classifications
H; H01; H01G; H01G4/00; H01G4/002; H01G4/018; H01G4/04; G; G01; G01F; G01F23/00; G01F23/22; G01F23/26; G01F23/263
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
133 words
A capacitance probe comprising: housing means having cavity means therein; means defining an aperture in said housing means extending from an outer surface of said housing means and communicating with said cavity means; capacitor means including a conductor extending away from said housing means and having a portion extending into said cavity means through said aperture; insulating spacer means in said aperture for fixedly retaining said portion of said conductor in said aperture; said insulating spacer means extending into said cavity means and surrounding said portion of said conductor; and circuit board means in said cavity means supported on said insulating spacer means for supporting electrical components associated with said capacitor means; said circuit board means having an aperture therein receiving said portion of said conductor therethrough for retention on said insulating spacer.
Claim 2
Dependent Claim
133 words
A capacitance probe comprising: housing means having cavity means therein; means defining an aperture in said housing means extending from an outer surface of said housing means and communicating with said cavity means; capacitor means including a conductor extending away from said housing means and having a portion extending into said cavity means through said aperture; insulating spacer means in said aperture for fixedly retaining said portion of said conductor in said aperture; said insulating spacer means extending into said cavity means and surrounding said portion of said conductor; and circuit board means in said cavity means supported on said insulating spacer means for supporting electrical components associated with said capacitor means; said circuit board means having an aperture therein receiving said portion of said conductor therethrough for retention on said insulating spacer.
Claim 3
Dependent Claim
23 words
The invention of claim 1 wherein said capacitor means includes an outer sleeve extending away from said housing means and surrounding said conductor.
Claim 4
Dependent Claim
20 words
The invention of claim 2 wherein said outer sleeve is a conductive sleeve which is insulatingly spaced from said conductor.
Claim 5
Dependent Claim
23 words
The invention of claim 3 wherein said conductive sleeve contains at least one aperture disposed therein at a position adjacent said housing means.
Claim 6
Dependent Claim
30 words
The invention of claim 2 wherein said outer sleeve is an insulating sleeve, and further including means sealing the extended portion of the sleeve to enclose the conductor member therein.
Claim 7
Dependent Claim
185 words
A capacitance probe comprising: housing means having cavity means therein; aperture means in said housing means extending from an outer surface of said housing means and communicating with said cavity means; capacitor means including a cylindrical conductor extending away from said housing means and having a smaller diameter shaft portion extending into said cavity means through said aperture means; said capacitor means also including an outer insulating sleeve having a portion extending away from said housing means and surrounding said cylindrical conductor; insulating spacer means in said aperture means and extending into said cavity means for fixedly retaining the shaft portion of said cylindrical conductor in said aperture means; circuit board means in said cavity means supported on said insulating spacer means for supporting electrical components associated with said capacitor means; said circuit board means having an aperture therein receiving said shaft portion therethrough for retention on said insulating spacer means; and means sealing the extended portion of the sleeve to enclose the cylindrical conductor therein including an insulating plug disposed in the sleeve and a sealing ring disposed between said plug and said sleeve.
Claim 8
Dependent Claim
185 words
A capacitance probe comprising: housing means having cavity means therein; aperture means in said housing means extending from an outer surface of said housing means and communicating with said cavity means; capacitor means including a cylindrical conductor extending away from said housing means and having a smaller diameter shaft portion extending into said cavity means through said aperture means; said capacitor means also including an outer insulating sleeve having a portion extending away from said housing means and surrounding said cylindrical conductor; insulating spacer means in said aperture means and extending into said cavity means for fixedly retaining the shaft portion of said cylindrical conductor in said aperture means; circuit board means in said cavity means supported on said insulating spacer means for supporting electrical components associated with said capacitor means; said circuit board means having an aperture therein receiving said shaft portion therethrough for retention on said insulating spacer means; and means sealing the extended portion of the sleeve to enclose the cylindrical conductor therein including an insulating plug disposed in the sleeve and a sealing ring disposed between said plug and said sleeve.
Claim 9
Dependent Claim
45 words
The invention of claim 1 wherein the means defining an aperture in said housing means comprises a housing having a cylindrical inner bore and a cylindrical outer surface coaxial with said bore, and screw threads on said cylindrical outer surface for mounting the capacitance probe.
Claim 10
Dependent Claim
18 words
The invention of claim 7 wherein the housing means has a hexagonal outer surface portion to facilitate mounting.
Claim 11
Dependent Claim
118 words
A capacitance probe comprising: housing means having cavity means therein; aperture means in said housing means extending from an outer surface of said housing means and communicating with said cavity means; capacitor means including a cylindrical conductor extending away from said housing means and having a smaller diameter shaft portion extending into said cavity means through said aperature means; insulating spacer means in said aperture means and extending into said cavity means for fixedly retaining the shaft portion of said cylindrical conductor in said aperture means; and a circuit board in said cavity means having a aperture therein receiving said shaft portion therethrough and supported on said spacer means for supporting electrical components associated with said capacitor means.
Claim 12
Dependent Claim
118 words
A capacitance probe comprising: housing means having cavity means therein; aperture means in said housing means extending from an outer surface of said housing means and communicating with said cavity means; capacitor means including a cylindrical conductor extending away from said housing means and having a smaller diameter shaft portion extending into said cavity means through said aperature means; insulating spacer means in said aperture means and extending into said cavity means for fixedly retaining the shaft portion of said cylindrical conductor in said aperture means; and a circuit board in said cavity means having a aperture therein receiving said shaft portion therethrough and supported on said spacer means for supporting electrical components associated with said capacitor means.
Claim 13
Dependent Claim
34 words
The invention of claim 9 wherein the shaft portion extending into said cavity means is screw threaded and further including nuT means on said screw threaded shaft portion retaining said circuit board in place.
Claim 14
Dependent Claim
36 words
The invention of claim 9 wherein the housing means has an insulating partition therein adjacent said cavity means and terminal means affixed to said partition and extending from outside said housing means into said cavity means.
Claim 15
Dependent Claim
21 words
The invention of claim 11 wherein said terminal means includes a voltage supply terminal, a test terminal and a signal terminal.
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) | 1977-08-19 | 1978-02-18 | 1978-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-19 | 1982-02-18 | 1982-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-19 | 1986-02-18 | 1986-08-20 | $7700.00 | Window Closed / Lapsed |