Patent US3728615A successfully refreshed from Google Patents.
US3728615A
Expired / Lapsed
US
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Smoke, gas, or rapid temperature increase detector utilizing a periodic electric field to create a self-sustained avalanche current
Assignee: Eaton Corp
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Filing: 1969-10-29
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Granted: 1973-04-17
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Expires: 1989-10-29
Abstract
Abstract A method and apparatus for detecting smoke, gaseous products of combustion such as CO, CO2, and a rapid temperature rise, the method including the steps of periodically forming, in a location exposed to the ambient atmosphere to bet tested, an electric field of sufficient intensity and of the proper configuration to produce a self-sustained Townsend avalanche, and comparing the resultant current flow with that produced in a similar such electric field created at the same time in an area shielded from the ambient atmosphere to be tested. When the current flow difference is of a sufficient magnitude due to the presence of smoke, gaseous products of combustion, or the occurrence of a sudden temperature rise, an alarm or fire control device is operated. In a second version, the current flow in an electric field formed earlier in time in the same location serves as the reference. The apparatus includes a pulsing circuit to periodically apply a high voltage to a pair of detector tubes having center electrodes, one tube being exposed to the ambient atmosphere, the other shielded. In the second version, a pulsing circuit periodically applies a voltage to a single detector tube and a holding and comparison circuit is provided to compare successive pairs of voltage pulses created by current flows caused by the periodic application of high voltages to the tube.
Inventors
- 👤 W Hill
- 👤 I Gurol
- 👤 S Dave
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:17
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/62; G01N27/68; G01N27/70; G08; G08B; G08B17/00; G08B17/10; G08B17/11
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
139 words
An apparatus for detecting an abnormal condition in an atmosphere such as the existence of smoke, gaseous products of combustion, or increases in ambient temperature in said atmosphere, said apparatus comprising: A. means producing periodic voltage pulses having a substantially constant voltage throughout the duration of each of said pulses; B. first electric field means responsive to said pulses for establishing a first periodic electric field in said atmosphere in which a self-sustained avalanche current will occur for the duration of each of said pulses; C. means providing a periodic reference current representative of a self-sustained avalanche current which would occur in an electric field in the absence of said abnormal conditions in said atmosphere; and D. comparing means producing an output signal in response to a predetermined difference between said first electric field current and said reference current.
Claim 2
Independent Claim
139 words
An apparatus for detecting an abnormal condition in an atmosphere such as the existence of smoke, gaseous products of combustion, or increases in ambient temperature in said atmosphere, said apparatus comprising: A. means producing periodic voltage pulses having a substantially constant voltage throughout the duration of each of said pulses; B. first electric field means responsive to said pulses for establishing a first periodic electric field in said atmosphere in which a self-sustained avalanche current will occur for the duration of each of said pulses; C. means providing a periodic reference current representative of a self-sustained avalanche current which would occur in an electric field in the absence of said abnormal conditions in said atmosphere; and D. comparing means producing an output signal in response to a predetermined difference between said first electric field current and said reference current.
Claim 3
Dependent Claim
45 words
The apparatus of claim 1, wherein said means providing said periodic reference current includes: E. second electric field means partially sealed from said atmosphere and responsive to said pulses for establishing a second periodic electric field in which said self-sustained avalanche reference current will occur.
Claim 4
Dependent Claim
60 words
The apparatus of claim 1, wherein said means providing said periodic reference current includes: E. hold means for holding a current occurring in said first periodic electric field during said duration of one of said pulses; and F. means transmitting the held current to said comparing means for comparison with a subsequent current occurring in said first periodic electric field.
Claim 5
Dependent Claim
36 words
The apparatus of claim 1, wherein E. said periodic voltage pulses are positive in polarity; and wherein F. said self-sustained avalanche current occurring for the duration of each of said pulses is a positive corona current.
Claim 6
Independent Claim
122 words
A method of detecting an abnormal condition such as the presence of smoke, gaseous products of combustion, or increases in ambient temperature in an atmosphere, comprising the steps of: A. producing periodic voltage pulses having a substantially constant voltage throughout the duration of each of said pulses; B. establishing a first periodic electric field in response to said pulses in which there is a self-sustained avalanche current during each of said pulses; C. providing a periodic reference current representative of a self-sustained avalanche current which would occur in an electric field in the absence of said abnormal conditions in said atmosphere; and D. producing an output signal when said first electric field current and said reference current differ by a predetermined amount.
Claim 7
Independent Claim
122 words
A method of detecting an abnormal condition such as the presence of smoke, gaseous products of combustion, or increases in ambient temperature in an atmosphere, comprising the steps of: A. producing periodic voltage pulses having a substantially constant voltage throughout the duration of each of said pulses; B. establishing a first periodic electric field in response to said pulses in which there is a self-sustained avalanche current during each of said pulses; C. providing a periodic reference current representative of a self-sustained avalanche current which would occur in an electric field in the absence of said abnormal conditions in said atmosphere; and D. producing an output signal when said first electric field current and said reference current differ by a predetermined amount.
Claim 8
Dependent Claim
58 words
The method of claim 5, wherein said step providing said periodic reference current includes the steps of: E. establishing a second periodic electric field in response to said pulses in which there is a self-sustained avalanche current representative of said reference current; and F. shielding said second periodic electric field from the entrance of Said abnormal atmospheric conditions.
Claim 9
Dependent Claim
64 words
The method of claim 5, wherein said step providing said periodic reference current includes the steps of: E. holding a current occurring in said first periodic electric field during said duration of one of said pulses; and F. transmitting the held current for comparison with a subsequent current occurring in said first periodic electric field during the duration of one of the subsequent pulses.
Claim 10
Independent Claim
137 words
A method of detecting an abnormal condition such as the presence of smoke, gaseous products of combustion, or increases in ambient temperature in an atmosphere, comprising the steps of: A. producing positive periodic voltage pulses having a substantially constant voltage throughout the duration of each of said pulses; B. establishing a periodic electric field in response to said positive pulses in which there is a positive corona current during the duration of each of said pulses; C. providing a periodic reference current representative of a corona current which would occur in an electric field in the absence of one of said abnormal conditions in said atmosphere; D. comparing said first electric field current with said reference current; and E. producing an output signal when said electric field current and said reference current differ by a predetermined amount.
Claim 11
Independent Claim
137 words
A method of detecting an abnormal condition such as the presence of smoke, gaseous products of combustion, or increases in ambient temperature in an atmosphere, comprising the steps of: A. producing positive periodic voltage pulses having a substantially constant voltage throughout the duration of each of said pulses; B. establishing a periodic electric field in response to said positive pulses in which there is a positive corona current during the duration of each of said pulses; C. providing a periodic reference current representative of a corona current which would occur in an electric field in the absence of one of said abnormal conditions in said atmosphere; D. comparing said first electric field current with said reference current; and E. producing an output signal when said electric field current and said reference current differ by a predetermined amount.
Claim 12
Independent Claim
133 words
An apparatus for detecting changes in the condition of an atmosphere such as smoke, gaseous products of combustion, or temperature, said apparatus comprising: A. means producing positive periodic voltage pulses having substantially constant voltage throughout the duration of each of said pulses; B. first electric field means responsive to said positive pulses for establishing a first electric field in said atmosphere in which a first positive corona current will occur during each of said pulses; C. second electric field means partially sealed from said atmosphere and responsive to said positive pulses for establishing a second electric field in which a second positive corona current will occur during each of said pulses; and D. comparing means producing an output signal in response to a predetermined difference between said first and second positive corona currents.
Claim 13
Independent Claim
133 words
An apparatus for detecting changes in the condition of an atmosphere such as smoke, gaseous products of combustion, or temperature, said apparatus comprising: A. means producing positive periodic voltage pulses having substantially constant voltage throughout the duration of each of said pulses; B. first electric field means responsive to said positive pulses for establishing a first electric field in said atmosphere in which a first positive corona current will occur during each of said pulses; C. second electric field means partially sealed from said atmosphere and responsive to said positive pulses for establishing a second electric field in which a second positive corona current will occur during each of said pulses; and D. comparing means producing an output signal in response to a predetermined difference between said first and second positive corona currents.
Claim 14
Independent Claim
130 words
An apparatus for detecting changes in the condition of an atmosphere such as smoke, gaseous products of combustion, and temperature, said apparatus comprising: A. means producing positive periodic voltage pulses having a substantially constant voltage throughout the duration of each of said pulses; B. electric field means responsive to said positive pulses of establishing a periodic electric field in said atmosphere in which a positive corona current will occur during each of said pulses; C. hold means for holding a current occurring in said periodic electric field during the duration of one of said pulses; and D. comparing means producing an output signal in response to a predetermined difference between the held current and a current occurring in said electric field in response to a subsequent one of said pulses.
Claim 15
Independent Claim
130 words
An apparatus for detecting changes in the condition of an atmosphere such as smoke, gaseous products of combustion, and temperature, said apparatus comprising: A. means producing positive periodic voltage pulses having a substantially constant voltage throughout the duration of each of said pulses; B. electric field means responsive to said positive pulses of establishing a periodic electric field in said atmosphere in which a positive corona current will occur during each of said pulses; C. hold means for holding a current occurring in said periodic electric field during the duration of one of said pulses; and D. comparing means producing an output signal in response to a predetermined difference between the held current and a current occurring in said electric field in response to a subsequent one of said pulses.
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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 |