US4642559A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrostatic field meter
Assignee: Texaco Inc
•
Filing: 1983-12-12
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Granted: 1987-02-10
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Expires: 2003-12-12
Abstract
Abstract An electrostatic field meter includes a field head which develops an electrical charge representative of the strength of an electrostatic field at the location of the field head. The electrical charge is converted to an AC signal which is then provided to metering apparatus. The metering apparatus provides an indication of the strength of the electrostatic field in accordance with the AC signal.
Inventors
- 👤 Carlton M. Slough
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:21
CPC Classifications
G; G01; G01R; G01R29/00; G01R29/12
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
84 words
A hand holdable electrostatic field meter comprising: head means for deriving an electrical charge representative of the direction and strength of an electrostatic field in the presence of the electrostatic field, converting means for converting the electrical charge to an AC signal, means for providing an indication of the strength of the electrostatic field in accordance with the AC signal from the converting means, and a housing for housing all of the elements in a manner so that the meter may be hand held.
Claim 2
Dependent Claim
84 words
A hand holdable electrostatic field meter comprising: head means for deriving an electrical charge representative of the direction and strength of an electrostatic field in the presence of the electrostatic field, converting means for converting the electrical charge to an AC signal, means for providing an indication of the strength of the electrostatic field in accordance with the AC signal from the converting means, and a housing for housing all of the elements in a manner so that the meter may be hand held.
Claim 3
Dependent Claim
62 words
A meter as described in claim 1 in which the converting means includes: switch means for passing the electrical charge to ground when in an on state and for not passing the charge to ground when in an off state, and oscillator means for providing an AC signal to the switch means so as to repetitively change the state of switch means.
Claim 4
Dependent Claim
72 words
A meter as described in claim 2 in which the indication means includes: a blocking capacitor receiving the AC signal, operational amplifier means for amplifying the AC signal which has passed through the blocking capacitor, means for rectifying the signal from the operational amplifier means, and a microammeter which receives the rectified signal from the rectifying means and provides the indication of the electrostatic field strength in accordance with the rectified signal.
Claim 5
Dependent Claim
30 words
A meter as described in claim 3 further comprising: means connected to the operational amplifier means and to the rectifier means for controlling the range of readings by the meter.
Claim 6
Dependent Claim
70 words
A meter as described in claim 4 in which the head means includes: shielding means for providing an electrostatic shield from all directions but one, means spatially arranged within the shield means for developing a charge representative of the electrostatic field, and means connected to the developing means, to the switching means and to blocking capacitor for conducting the developed charge to the switching means and to the blocking capacitor.
Claim 7
Dependent Claim
25 words
A meter as described in claim 4 in which the developing means is held rigidly in place within the shield means by a support member.
Claim 8
Dependent Claim
54 words
A meter as described in claim 6 in which the developing means includes: an insulator member having a metalized surface which is exposed to the electrostatic field, and in which the conducting means conducts the charge developed on the metalized surface through the insulator member to the switching means and to the blocking capacitor.
Claim 9
Dependent Claim
13 words
A meter as described in claim 6 in which the developing means includes:
Claim 10
Dependent Claim
45 words
an insulator member that is in contact with all sides of the shield save one, and a metal disc embedded in said insulator member in a manner so that it is exposed to the electrostatic field and does not make contact with the shield means.
Claim 11
Dependent Claim
45 words
an insulator member that is in contact with all sides of the shield save one, and a metal disc embedded in said insulator member in a manner so that it is exposed to the electrostatic field and does not make contact with the shield means.
References Cited (Backward Citations)
US3421982A
Cited
US3828250A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-02-09 | 1990-08-11 | 1991-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-09 | 1994-08-11 | 1995-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-09 | 1998-08-11 | 1999-02-10 | $7700.00 | Window Closed / Lapsed |