US3728706A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System for indicating aerosols in the atmosphere
Assignee: SPX Technologies Inc
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Filing: 1970-09-28
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Granted: 1973-04-17
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Expires: 1990-09-28
Abstract
Abstract A fire detector having an ionization sensing means which changes the level of an output signal in accordance with sensing the presence of smoke in the atmosphere has been provided. A detecting means selectively responsive to the output signal generates an alarm control signal and the improvement includes a filter means for rendering a detecting means operable if uninhibited to generate the alarm signal irrespective of an output signal from the sensing means. Inhibiting means normally operable to inhibit the filter is rendered ineffective in response to the output signal of the sensing means and the inhibiting means therefore checks the operability of the detecting means.
Inventors
- 👤 W Tipton
- 👤 M Suchomel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:19
CPC Classifications
G; G08; G08B; G08B17/00; G08B17/10; G08B17/11; G08B17/113
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
135 words
A fire detector including; ionization sensing means for increasing the level of an output signal relative to a normal threshold value in accordance with sensing the presence of smoke in the atmosphere, and detecting means selectively responsive to the output signal for generating an alarm control signal wherein the improvement comprises: filter means effective if uninhibited for generating the alarm signal; and inhibiting means including a voltage level detector governed by the output signal, operable to inhibit the filter means only if the output signal is within a normal voltage range, whereby an alarm signal is generated when the output signal is above the voltage range as when smoke is present in the chamber or when the output signal is below the voltage range as when there is a malfunction in the ionization sensing means.
Claim 2
Dependent Claim
135 words
A fire detector including; ionization sensing means for increasing the level of an output signal relative to a normal threshold value in accordance with sensing the presence of smoke in the atmosphere, and detecting means selectively responsive to the output signal for generating an alarm control signal wherein the improvement comprises: filter means effective if uninhibited for generating the alarm signal; and inhibiting means including a voltage level detector governed by the output signal, operable to inhibit the filter means only if the output signal is within a normal voltage range, whereby an alarm signal is generated when the output signal is above the voltage range as when smoke is present in the chamber or when the output signal is below the voltage range as when there is a malfunction in the ionization sensing means.
Claim 3
Dependent Claim
48 words
The fire detector of claim 1 wherein said detecting means comprises: a field effect transistor amplifier having its input governed by the output signal and switching means including a plurality of electronic gates energized in accordance with an output of the amplifier For generating said alarm output signal.
Claim 4
Dependent Claim
57 words
The fire detector of claim 2 wherein said inhibiting means includes: charging means coupled to a first of said gates, said first gate being responsive to the level of the output of the amplifier and said charging means to periodically trigger said gate upon each accumulation of energy beyond the level of said output of the amplifier.
Claim 5
Dependent Claim
21 words
The fire detector of claim 3 wherein said charging means includes a resistor and capacitor combination coupled to said first gate.
Claim 6
Dependent Claim
28 words
The fire detector of claim 4 wherein said filter means comprises: timing means responsive to the periodic triggering of said first gate producing a pulse for each occurrence.
Claim 7
Dependent Claim
80 words
The fire detector of claim 5 wherein said timing means includes a charging circuit coupled between a second and third of said gates, said charging circuit being discharged through said second gate when said second gate is in a conductance state, said second gate conductance state being governed by said triggering of said first gate; and the third gate being turned on to produce a signal when said charging rate is less than said triggering rate of said first gate.
Claim 8
Dependent Claim
33 words
The fire detector of claim 6 wherein said detecting means includes: a fourth of said gates, operative to produce said output alarm signal in response to the conductance state of said third gate.
Claim 9
Dependent Claim
31 words
A system as defined in claim 1 further comprising: centrally located control means including line wires coupled to each of a plurality of said fire detectors for indicating said alarm condition.
Claim 10
Dependent Claim
43 words
A system as defined in claim 8 wherein said indicating means comprises: current sensitive means responsive to a change in current occasioned by the occurrence of said alarm signal for providing said indication including a relay energized in accordance with said current increase.
Claim 11
Dependent Claim
79 words
A system as defined in claim 8 further comprising: an end of line code sender connected across the line wires for terminating a line circuit connecting the detectors to the centrally located control means including: an oscillator powered by energy applied to the line wires for generating pulses for transmission over the line wires to the centrally located control means, and centrally located receiver means responsive to said pulses for indicating a trouble condition upon the cessation of pulses.
Claim 12
Dependent Claim
82 words
A system as defined in claim 10 wherein said receiver means comprises: switching means having a conductance state in accordance with said pulsed energy signals, timing means including a resistor and capacitor charging circuit discharged each time said switching means is in its conductance state, said charging circuit having a discharge time greater than the normal frequency of said pulsed energy; and means responsive to a charged condition of said charging means for indicating a trouble condition upon the cessation of pulses.
Claim 13
Dependent Claim
74 words
The fire detector of claim 1 wherein said ionization sensing means comprises: two ionization chambers coupled serially across a source of low voltage including a reference chamber and a measuring chamber, said reference chamber being substantially isolated from smoke particles establishing a reference potential for said detector and said measuring chamber serially coupled adjacent to said reference chamber for producing a change in the level of said reference potential thereby providing said output signal.
Claim 14
Dependent Claim
101 words
The fire detector of claim 1 comprising: a base member; a cylindrical tube of insulative material mounted thereto; a common electrode plate secured coaxially within said tube, said electrode coupled to said detector means; a reference electrode substantially parallel with said common electrode movably mounted to said base for establishing the reference potential in accordance with the spacing of said common electrode and said reference electrode; a measuring electrode mounted to said base at the opposite end of said tube in spaced relation with the oppositE side of said common electrode, said measuring electrode having openings therein for admitting smoke particles.
Claim 15
Dependent Claim
50 words
The fire detector of claim 13 wherein said ionization chamber includes a source of alpha particle emitting material disposed on each side of said common electrode for ionizing the atmosphere with said chambers and producing an ionization current in accordance with a potential imposed across the reference and measuring electrodes.
Claim 16
Dependent Claim
46 words
The fire detector of claim 14 wherein said measuring electrode and the associated side of said common electrode are in a spaced relation such that the walls of the tube tend to columnate the alpha particles towards said measuring electrode for uniform ionization of the atmosphere.
References Cited (Backward Citations)
US2646556A
Cited
US3462752A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-16 | 1976-10-16 | 1977-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-16 | 1980-10-16 | 1981-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-16 | 1984-10-16 | 1985-04-17 | $7700.00 | Window Closed / Lapsed |