US3678488A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-adjusting condensation nuclei monitor measuring circuit having adjustable gain
Assignee: Environment One Corp
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Filing: 1971-02-08
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Granted: 1972-07-18
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Expires: 1991-02-08
Abstract
Abstract A detecting and amplifying circuit for a multi-zone fire and/or detection system comprising a common sensor-detector located at a control station for detecting and signaling the existence of an alarm condition in any one of the zones being monitored. The common sensor-detector preferably comprises a condensation nuclei monitor and is selectively switched from one zone to the next to monitor conditions in each respective zone sequentially. The rate at which the zones are monitored is relatively rapid on the order of once every 10 minutes or slow depending upon the number of zones, etc. An output feedback amplifier is coupled to the output from the common condensation nuclei sensor-detector for amplifying the output signals derived from the detector. A plurality of gain change resistors are selectively connectable in the feedback path of the output feedback amplifier to adjust its gain selectively to a number of different values. Cam operated switches which are operated synchronously with the selective switching of the common condensation nuclei sensor detector from one zone to the next operate to connect in preselected ones of the resistors into effective circuit relationship in the feedback path of the output feedback amplifier. Consequently, the sensitivity of the overall detecting and amplifying circuit is individually adjusted to background conditions existing in each of the zones being monitored synchronously with the switching of the common condensation nuclei monitor sensor-detector from one zone to the next. The condensation nuclei monitor is of the selfadjusting type including a first photo cell detector for detecting short term changes in light level of a light beam impinging on the photo cell as opposed to longer term changes in operating characteristics of the photo cell due to temperature effects, dust accumulation in the optical path, aging and the like. Self-adjustment is provided by a second lamp-photo cell module having the photo cell connected in circuit relationship with the first nuclei particle sensing photo cell for maintaining substantially constant long term electric energization conditions across the first photo cell. A first output feedback amplifier is provided with the first photo cell connected in its feedback path and is responsive to both fast and long time constant changes in operating conditions of the first photo cell. The lamp of the lamp-photo cell module is connected in a second long time constant feedback path of the first feedback amplifier for controlling the intensity of the light impinging on the second photo cell whereby substantially constant long term electric energization conditions are maintained across the first nuclei particle sensing photo cell. By reason of the inclusion of the feedback lamp-photo cell module in the long time constant feedback path, isolation between the output of the feedback amplifier and the input to the nuclei particle sensing photo cell, is provided.
Inventors
- 👤 George F Skala
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 00:57
CPC Classifications
G; G08; G08B; G08B17/00; G08B17/10; G08B17/103; G08B17/107; G01; G01N; G01N15/00; G01N15/06; G01N15/065
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
248 words
A self-adjusting electro-optical detecting and amplifying circuit comprising an electro-optical detecting means for sensing short term changes in light level of a light beam impinging thereon as distinguished from longer term changes in operating characteristics due to temperature effects, dust accumulation in the optical path, ageing and the like, a source of electric energy, second electro-optic detecting means connected in circuit relationship with said first mentioned electro-optic detecting means and said source of electric energy for maintaining substantially constant long term electric energization conditions across the first electro-optic detecting means, inverting feedback amplifier means having the first electro-optic detecting means connected in a first fast time constant feedback path and responsive to both long and short term changes in operating conditions of said first electro-optic detecting means, a feedback light source for directing a beam of light onto the second electro-optic detecting means for controlling its electric resistivity, long time constant feedback circuit means coupling the output of said inverting feedback amplifier means to the feedback light source for controlling the intensity of the feedback light source to thereby maintain substantially constant long term electric energization conditions across said first electro-optic detecting means, and output indicating means responsive substantially only to the short term changes in the electric signal derived by the first electro-optic detecting means and coupled to the output from the inverting feedback amplifier means for deriving an output indication of the short term transient changes in light level sensed by the first electro-optic detecting means.
Claim 2
Dependent Claim
248 words
A self-adjusting electro-optical detecting and amplifying circuit comprising an electro-optical detecting means for sensing short term changes in light level of a light beam impinging thereon as distinguished from longer term changes in operating characteristics due to temperature effects, dust accumulation in the optical path, ageing and the like, a source of electric energy, second electro-optic detecting means connected in circuit relationship with said first mentioned electro-optic detecting means and said source of electric energy for maintaining substantially constant long term electric energization conditions across the first electro-optic detecting means, inverting feedback amplifier means having the first electro-optic detecting means connected in a first fast time constant feedback path and responsive to both long and short term changes in operating conditions of said first electro-optic detecting means, a feedback light source for directing a beam of light onto the second electro-optic detecting means for controlling its electric resistivity, long time constant feedback circuit means coupling the output of said inverting feedback amplifier means to the feedback light source for controlling the intensity of the feedback light source to thereby maintain substantially constant long term electric energization conditions across said first electro-optic detecting means, and output indicating means responsive substantially only to the short term changes in the electric signal derived by the first electro-optic detecting means and coupled to the output from the inverting feedback amplifier means for deriving an output indication of the short term transient changes in light level sensed by the first electro-optic detecting means.
Claim 3
Dependent Claim
31 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 1 wherein said feedback light source and said second electro-optic detecting means comprise an integrally packaged single housing lamp-photo cell module.
Claim 4
Dependent Claim
49 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 1 further including sensing resistor means connected in series circuit relationship with said second electro-optic detecting means for monitoring the operating condition of the circuit and indicating the need for servicing, cleaning or replacement of the electro-optic detecting means.
Claim 5
Dependent Claim
117 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 1 further including second feedback amplifier means connected to the output from said first mentioned inverting feedback amplifier means, said second feedback amplifier means including a plurality of gain changing resistors selectively connectable in circuit relationship in the feedback path, and selectively operable switching means connected in circuit relationship with the gain changing resistors for automatically and sequentially connecting desired ones of the gain changing resistors into effective circuit relationship in the feedback path of the second feedback amplifier means whereby the gain of the second feedback amplifier means automatically is adjusted to correspond to the individual background conditions being monitored by the first electro-optic detecting means.
Claim 6
Dependent Claim
100 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 4 further including peak detecting circuit means connected to the output of the second feedback amplifier means, peak signal storing means responsive to the output of the peak detecting circuit means, level sensing and comparison circuit means coupled to said peak signal storing means for comparing the peak amplitude of the output signal to a predetermined maximum reference level and deriving an output alarm indication in the event that the peak amplitude of the output signal exceeds the maximum reference value established by the level sensing and comparison circuit means.
Claim 7
Dependent Claim
59 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 5 further including alarm indicating means coupled to and actuated by the level sensing and comparison circuit means and means for desensitizing the alarm indicator over a predetermined time interval synchronously with the switching of the gain changing resistors in the feedback path of the second feedback amplifier means.
Claim 8
Dependent Claim
131 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 6 wherein the alarm indicating means coupled to the output of the level sensing and comparison circuit means includes a charging capacitor, switching means responsive to the output from the level sensing and comparison circuit means for maintaining said charging capacitor in the first condition serving to maintain the alarm indicating means in its non-alarm condition, and said means for desensitizing the alarm indicating means comprises cam actuated switch means for clamping the charging capacitor to a source of electric potential whereby the charging capacitor is maintained at the preset non-alarm first condition during the short time duration sample switching operation synchronously with the switChing in of the gain changing resistors in the feedback path of the second feedback amplifier means.
Claim 9
Dependent Claim
120 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 7 further including third output amplifier means connected to the output from said first mentioned inverting feedback amplifier means in parallel with the second feedback amplifier means, voltage level clipping means coupled to the output of the third output amplifier means for limiting the output voltage derived therefrom to a predetermined value, rectifying and filter circuit means coupled to the output from said voltage level clipping circuit means, and malfunction alarm indicating means coupled to the output from the rectifying and filter circuit means for indicating the existence of a malfunction condition upon the voltage derived from the rectifying and filter circuit means dropping below a predetermined minimum reference value.
Claim 10
Dependent Claim
45 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 8 wherein the first mentioned alarm indicating means and the malfunction alarm indicating means all comprise fail-safe relay actuated circuit means for signalling the existence of an alarm and/or malfunction condition in a fail-safe manner.
Claim 11
Dependent Claim
59 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 9 further including additional time controlled gain changing resistors selectively connectable in the feedback path of said second feedback amplifier means in accordance with a predetermined day and night schedule for further selectively adjusting the gain of said second feedback amplifier means in accordance with the time of day.
Claim 12
Dependent Claim
91 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 10 wherein the first electro-optic detecting means comprises the detecting element of a condensation nuclei monitor and feedback light source and second electro-optic detecting means comprise an integrally packaged single housing lamp-photo cell module, and further including sensing resistor means connected in series circuit relationship with the second electro-optic detecting means for monitoring the operating condition of the condensation nuclei monitor detecting and amplifying circuit in order to ascertain the need for servicing, cleaning or replacement of the electro-optic detecting elements.
Claim 13
Dependent Claim
229 words
A detecting and amplifying circuit for a multi-zone monitoring apparatus comprising a common highly sensitive sensor-detector located at a central control station for detecting and signalling the existence of an alarm condition in any one of the zones being monitored, the input to the common sensor-detector being automatically and sequentially switched from one zone to the next to selectively monitor conditions in the respective zones at a relatively rapid rate on the order of one every two or three minutes, output feedback amplifier means coupled to the output of the common-sensor detector for amplifying the output signals derived therefrom, a plurality of gain change resistors selectively connectable in the feedback path of the output feedback amplifier means to adjust the gain thereof to a number of different settings in accordance with which gain change resistors are selectively connected in the feedback path, and switching means operable synchronously with selective switching of the common sensor detector from one zone to the next for switching preselected ones of the gain changing resistors into effective circuit relationship in the feedback path of the output feedback amplifier whereby the sensitivity of the overall detecting and amplifying circuit is individually adjusted to background conditions existing in each of the zones being monitored synchronously with the switching of the common sensor detector from one zone to the next to monitor each of the respective zones.
Claim 14
Dependent Claim
229 words
A detecting and amplifying circuit for a multi-zone monitoring apparatus comprising a common highly sensitive sensor-detector located at a central control station for detecting and signalling the existence of an alarm condition in any one of the zones being monitored, the input to the common sensor-detector being automatically and sequentially switched from one zone to the next to selectively monitor conditions in the respective zones at a relatively rapid rate on the order of one every two or three minutes, output feedback amplifier means coupled to the output of the common-sensor detector for amplifying the output signals derived therefrom, a plurality of gain change resistors selectively connectable in the feedback path of the output feedback amplifier means to adjust the gain thereof to a number of different settings in accordance with which gain change resistors are selectively connected in the feedback path, and switching means operable synchronously with selective switching of the common sensor detector from one zone to the next for switching preselected ones of the gain changing resistors into effective circuit relationship in the feedback path of the output feedback amplifier whereby the sensitivity of the overall detecting and amplifying circuit is individually adjusted to background conditions existing in each of the zones being monitored synchronously with the switching of the common sensor detector from one zone to the next to monitor each of the respective zones.
Claim 15
Dependent Claim
100 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 12 further including peak detecting circuit means connecteD to the output of the output feedback amplifier means, peak signal storing means responsive to the ouptut from the peak detecting circuit means, level sensing and comparison circuit means coupled to said peak signal storing means for comparing the peak amplitude of the peak signal storing means to a predetermined maximum reference level and deriving an output alarm indication in the event that the peak amplitude of the output signal exceeds the maximum reference value established by the level sensing circuit means.
Claim 16
Dependent Claim
59 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 13 further including alarm indicating means coupled to and actuated by the level sensing and comparison circuit means and means for desensitizing the alarm indicator over a predetermined time interval synchronously with the switching of the gain changing resistors in the feedback path of the output feedback amplifier means.
Claim 17
Dependent Claim
162 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 14 wherein the alarm indicating means coupled to the output of the level sensing circuit means includes a charging capacitor, switching means responsive to the output from the level sensing circuit means for maintaining said charging capacitor in a first non-alarm condition in response to the output from the peak detecting circuit means remaining below the maximum reference level established by the level sensing circuit means, said charging capacitor in the first condition serving to maintain the alarm indicating means in its non-alarm condition, and said means for desensitizing the alarm indicating means comprises cam actuated switch means for clamping the charging capacitor to a source of electric potential whereby the charge on the charging capacitor is maintained at the preset non-alarm first condition during the short time duration sample switching operation synchronously with the switching in of the gain changing resistors in the feedback path of the second feedback amplifier means.
Claim 18
Dependent Claim
115 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 15 further including third output amplifier means connected to the output from said sensor-detector in parallel with the output feedback amplifier means, voltage level clipping means coupled to the output of the third output amplifier means for limiting the output voltage derived therefrom to a predetermined value, rectifying and filter circuit means coupled to the output from said voltage level clipping circuit means, and malfunction alarm indicating means coupled to the output from the rectifying and filter circuit means for indicating the existence of a malfunction condition upon the voltage derived from the rectifying and filter circuit means dropping below a predetermined minimum reference value.
Claim 19
Dependent Claim
45 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 16 wherein the first mentioned alarm indicating means and the malfunction alarm indicating means all comprise fail-safe relay actuated circuit means for signalling the existence of an alarm and/or malfunction condition in a fail-safe manner.
Claim 20
Dependent Claim
59 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 17 further including additional time controlled gain changing resistors selectively connectable in the feedback path of said output feedback amplifier means in accordance with a predetermined day and night schedule for further selectively adjusting the gain of said output feedback amplifier means in accordance with the time of day.
Claim 21
Dependent Claim
59 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 12 further including additional time controlled gain changing resistors selectively connectable in the feedback path of said output feedback amplifier means in accordance with a predetermined day and night schedule for further selectively adjusting the gain of said output feedback amplifier means in accordance with the time of day.
Claim 22
Dependent Claim
57 words
A self-adjusting electro-optical detecting and amplifying circuit according to claim 12 further including malfunction detecting circuit means coupled to the output from said sensor-detector in parallel with said first mentioned output feedback amplifier means for detecting and signalling the existence of a malfunction condition upon the output from the sensor-detector dropping below a preset minimum reference level.
References Cited (Backward Citations)
US3618061A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-18 | 1976-01-17 | 1976-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-18 | 1980-01-17 | 1980-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-18 | 1984-01-17 | 1984-07-18 | $7700.00 | Window Closed / Lapsed |