US4547675A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Smoke detector operating according to the radiation extinction principle
Assignee: Cerberus AG
•
Filing: 1981-12-07
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Granted: 1985-10-15
•
Expires: 2001-12-07
Abstract
Abstract A smoke detector contains two radiation transmitters and two radiation receivers. Each of the radiation transmitters emits in a different spectral region, for instance, one emits above and the other one below 600 nm. One part of the radiation of both radiation transmitters is conducted via a measuring path, which is accessible to smoke, to one of the receivers constituting a measuring radiation receiver, and another part of such radiation is conducted via a comparison path, which is not accessible to smoke, to the other of the receivers constituting a comparison radiation receiver. Connected to both radiation receivers is an evaluation circuit which forms from the measuring radiation intensities prevailing in the two spectral regions and from the comparison radiation intensities prevailing in the same spectral regions a function of the type: ##EQU1## By suitably adjusting or selecting the components of the evaluation circuit, the coefficients a and b are selected such that in the absence of smoke in the measuring path, A becomes zero and in the presence of smoke such is proportional to the smoke density.
Inventors
- 👤 Jurg Muggli
- 👤 Martin Labhart
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:15
CPC Classifications
G; G08; G08B; G08B17/00; G08B17/10; G08B17/103; G08B29/00; G08B29/18; G08B29/20; G08B29/24
Claims Analysis
Total Claims: 59
Claim 1
Independent Claim
164 words
In a smoke detector operating according to the radiation extinction principle, wherein the radiation attenuation caused by smoke is detected in a measuring path and at a predetermined radiation attenuation there is triggered a signal by means of an evaluation circuit, the improvement which comprises: a radiation transmitter for emitting radiation in a long wave spectral region; a radiation transmitter for emitting radiation in a shorter wave spectral region; means for providing a measuring path which is accessible to smoke; means for providing a comparison path which is accessible to smoke at least to a relatively restricted degree; a measuring radiation receiver for receiving the radiation of said two radiation transmitters after the same has passed through said measuring path which is at least relatively readily accessible to smoke; and a comparison radiation receiver for receiving the radiation of said two radiation transmitters after the same has passed through said comparison path which is accessible to smoke at least to a relatively restricted degree.
Claim 2
Dependent Claim
164 words
In a smoke detector operating according to the radiation extinction principle, wherein the radiation attenuation caused by smoke is detected in a measuring path and at a predetermined radiation attenuation there is triggered a signal by means of an evaluation circuit, the improvement which comprises: a radiation transmitter for emitting radiation in a long wave spectral region; a radiation transmitter for emitting radiation in a shorter wave spectral region; means for providing a measuring path which is accessible to smoke; means for providing a comparison path which is accessible to smoke at least to a relatively restricted degree; a measuring radiation receiver for receiving the radiation of said two radiation transmitters after the same has passed through said measuring path which is at least relatively readily accessible to smoke; and a comparison radiation receiver for receiving the radiation of said two radiation transmitters after the same has passed through said comparison path which is accessible to smoke at least to a relatively restricted degree.
Claim 3
Dependent Claim
186 words
The smoke detector as defined in claim 1, wherein: the evaluation circuit is constructed so that it forms an output signal; said evaluation circuit forming said output signal in response to a portion of the radiation from said radiation transmitter for emitting radiation in a longer wave spectral region and from said radiation transmitter for emitting radiation in a shorter wave spectral region which has passed through said measuring path and in response to a portion of said radiation which has passed through said comparison path according to the function: ##EQU7## wherein: A=said output signal; a=a first predeterminate device coefficient of the evaluation circuit; b=a second predeterminate device coefficient of the evaluation circuit; I R =intensity of said radiation received in said longer wave spectral region by said measuring radiation receiver; I RV =intensity of said radiation received in said longer wave spectral region by said comparison radiation receiver; I G =intensity of said radiation received in said shorter wave spectral region by said measuring radiation receiver; and I GV =intensity of said radiation received in said shorter wave spectral region by said comparison radiation receiver.
Claim 4
Dependent Claim
185 words
The smoke detector as defined in claim 1, wherein: said evaluation circuit is constructed such that it forms an output signal; said evaluation circuit forming said output signal in response to a portion of the radiation from said radiation transmitter for emitting radiation in alonger wave spectral region and from said radiation transmitter for emitting radiation in a shorter wave spectral region which has passed through said measuring path and in response to a portion of said radiation which has passed through said comparison path according to the function: ##EQU8## wherein: B=said output signal; a=a first predeterminate device coefficient of the evaluation circuit; b=a second predeterminate device coefficient of the evaluation circuit; I R =intensity of said radiation received in said longer wave spectral region by said measuring radiation receiver; I RV =intensity of said radiation received in said longer wave spectral region by said comparison radiation receiver; I G =intensity of said radiation received in said shorter wave spectral region by said measuring radiation receiver; and I GV =intensity of said radiation received in said shorter wave spectral region by said comparison radiation receiver.
Claim 5
Dependent Claim
43 words
The smoke detector as defined in claim 2 or 3, wherein: the evaluation circuit contains predetermined circuit components connected to said comparison radiation receiver and selected such that in the absence of smoke in said meausring path said output signal is essentially zero.
Claim 6
Dependent Claim
49 words
The smoke detector as defined in claim 4, wherein: said predetermined circuit components include at least one operational amplifier and at least two resistors conjointly connected to said at least one operational amplifier to define at least one voltage divider for adjusting at least one of said device coefficients.
Claim 7
Dependent Claim
55 words
The smoke detector as defined in claim 2 or 3, wherein: said evaluation circuit is constructed such that in addition there is formed the magnitude: ##EQU9## wherein: E=a parameter dependent upon the type of smoke present; c=a third predeterminate device coefficient of the evaluation circuit; and d=a fourth predeterminate device coefficient of the evaluation circuit.
Claim 8
Dependent Claim
46 words
The smoke detector as defined in claim 2 or 3, wherein: said evaluation circuit is constructed such that in addition there is formed the magnitude: ##EQU10## wherein: G=a parameter dependent upon the type of smoke present; and g=a third predeterminate device coefficient of the evaluation circuit.
Claim 9
Dependent Claim
35 words
The smoke detector as defined in claim 2 or 3, wherein: said evaluation circuit is constructed such that at least one of said first and second predetermined device coefficients a and b is gradually adjustable.
Claim 10
Dependent Claim
32 words
The smoke detector as defined in claim 6, wherein: said evaluation circuit is constructed such that at least one of said predeterminate device coefficients a, b, c and d, is gradually adjustable.
Claim 11
Dependent Claim
31 words
The smoke detector as defined in claim 7, wherein: said evaluation circuit is constructed such that at least one of said predeterminate device coefficients a, b, and g is gradually adjustable.
Claim 12
Dependent Claim
42 words
The smoke detector as defined in claim 2 or 3, wherein: said evaluation circuit comprises circuit means for forming a means value of said output signal; and said evaluation circuit is constructed for comparing said output signal to said means value thereof.
Claim 13
Dependent Claim
40 words
The smoke detector as defined in claim 6, wherein: said evaluation circuit comprises circuit means for forming a means value of said output signal; and said evaluation circuit is constructed for comparing said output signal to said mean value thereof.
Claim 14
Dependent Claim
40 words
The smoke detector as defined in claim 7, wherein: said evaluation circuit comprises circuit means for forming a means value of said output signal; and said evaluation circuit is constructed for comparing said output signal to said mean value thereof.
Claim 15
Dependent Claim
35 words
The smoke detector as defined in claim 2 or 3, wherein said circuit being constructed so that there is additionally formed the time-differentiated quotient dA/dt or dB/dt, of the respective output signal A or B.
Claim 16
Dependent Claim
89 words
The smoke detector as defined in claim 1, further including: a radiation divider; and said radiation transmitters and said radiation receivers being arranged such that the radiation of one radiation transmitter arrives at the measuring radiation receiver upon deflection of said radiation divider, while arriving at the comparison radiation receiver upon passing through said radiation divider, whereas the radiation of the other radiation transmitter arrives at the measuring radiation receiver upon passing through said radiation divider, while arriving at the comparison radiation receiver upon reflection at said radiation divider.
Claim 17
Dependent Claim
19 words
The smoke detector as defined in claim 1, wherein: said two radiation transmitters are arranged immediately adjacent one another.
Claim 18
Dependent Claim
31 words
The smoke detector as defined in claim 1, further including: at least two radiation conductors arranged such that the radiation of said two radiation transmitters is conducted to immediately neighbouring locations.
Claim 19
Dependent Claim
49 words
The smoke detector as defined in claim 16 or 17, further including: a ground glass plate; said two radiation transmitters are arranged such that they irradiate said ground glass plate; and the radiation emanating from an irradiated surface of said ground glass plate being conducted to said measuring path.
Claim 20
Dependent Claim
26 words
The smoke detector as defined in claim 1, further including: a ridge prism for uniting the radiation of said two radiation transmitters at the measuring path.
Claim 21
Dependent Claim
30 words
The smoke detector as defined in claim 1, further including: a number of narrow adjacently arranged ridge prisms uniting the radiation of said two radiation transmitters at said measuring path.
Claim 22
Dependent Claim
33 words
The smoke detector as defined in claim 16 or 17, further including: a prism for substantially parallely aligning the radiation of the two adjacently arranged radiation transmitters by means of its prism dispersion.
Claim 23
Dependent Claim
36 words
The smoke detector as defined in claim 16, wherein: said two radiation transmitters are successively arranged in the direction of emission of the radiation; and the radiation of one radiation transmitter irradiating the other radiation transmitter.
Claim 24
Dependent Claim
43 words
The smoke detector as defined in claim 1, wherein: said two radiation transmitters are successively arranged in the direction of the radiation; and a bifocal Fresnel lens being provided for imaging the radiation of said two radiation transmitters onto the same image spot.
Claim 25
Dependent Claim
42 words
The smoke detector as defined in claim 1, wherein: one of said two radiation transmitters emitting radiation having a wavelength greater than 600 nm; and the other one of said two radiation transmitters emitting radiation having a wavelength less than 600 nm.
Claim 26
Dependent Claim
33 words
The smoke detector as defined in claim 1, wherein: said radiation transmitters are constructed such that mean values of the wavelength regions thereof are spaced from one another by at least 50 nm.
Claim 27
Dependent Claim
17 words
The smoke detector as defined in claim 1, wherein: said radiation transmitters are constructed as light-emitting diodes.
Claim 28
Dependent Claim
24 words
The smoke detector as defined in claim 1, wherein: said radiation transmitters are constructed as wideband radiation sources provided with forwardly arranged optical filters.
Claim 29
Dependent Claim
39 words
The smoke detector as defined in claim 1, wherein: said radiation transmitters are constructed as a wideband radiation source provided with a forwardly arranged optical filter; and the transmission region of said optical filter being changeable by electrical signals.
Claim 30
Dependent Claim
43 words
The smoke detector as defined in claim 1, wherein: said radiation transmitters are constructed as a wideband radiation source; an optical filter arranged forwardly of said radiation receivers; and the transmission region of said optical filter being changeable by means of electrical signals.
Claim 31
Dependent Claim
20 words
The smoke detector as defined in claim 1, wherein: said radiation transmitters are constructed as a variable light-emitting diode (LED).
Claim 32
Dependent Claim
25 words
The smoke detector as defined in claim 1, further including: at least one collimator optic means for collimating the radiation emanating from said radiation transmitters.
Claim 33
Dependent Claim
17 words
The smoke detector as defined in claim 1, wherein: said radiation transmitters are constructed as laser diodes.
Claim 34
Dependent Claim
37 words
The smoke detector as defined in claim 1, further including: at least one reflector arranged in said measuring path; and said reflector serving for reflecting the radiation of said two radiation transmitters onto said measuring radiation receiver.
Claim 35
Dependent Claim
38 words
The smoke detector as defined in claim 1, further including: a radiation conductor for removing the radiation of said radiation transmitters after the same has passed through said measuring path and guiding it to said measuring radiation receiver.
Claim 36
Dependent Claim
23 words
The smoke detector as defined in claim 33, further including: reflector elements arranged such that said measuring path has a substantially star-shaped configuration.
Claim 37
Dependent Claim
30 words
The smoke detector as defined in claim 1, wherein: said measuring radiation receiver and said comparison radiation receiver are incorporated in a common housing to form a dual radiation-radiation receiver.
Claim 38
Dependent Claim
32 words
The smoke detector as defined in claim 1, wherein: said evaluation circuit is structured such that it controls said radiation transmitters so that they emit continuous wave radiation in an alternating fashion.
Claim 39
Dependent Claim
23 words
The smoke detector as defined in claim 1, wherein: said evaluation circuit is constructed such that said radiation transmitters alternatingly emit radiation trains.
Claim 40
Dependent Claim
49 words
The smoke detector as defined in claim 1, wherein: said radiation measuring receiver generates an output signal containing an alternating component; said evaluation circuit is constructed such that said alternating component of the output signal of said measuring radiation receiver serves as a criterion for giving an alarm signal.
Claim 41
Dependent Claim
46 words
The smoke detector as defined in claim 1, further including: said evaluation circuit contains regulation means; and said regulation means regulating the radiation intensity of said two radiation transmitters in the corresponding wavelength region to a predetermined level as a function of the received comparison radiation.
Claim 42
Dependent Claim
22 words
The smoke detector as defined in claim 40, wherein: the regulation level for the radiation is adjustable in the two wavelength regions.
Claim 43
Dependent Claim
34 words
The smoke detector as defined in claim 1, wherein: said evaluation circuit is constructed such that the signal of at least one of the two radiation receivers is integrated as a function of time.
Claim 44
Dependent Claim
65 words
The smoke detector as defined in claim 1, wherein: said evaluation circuit is constructed such that the signal of at least one of the two radiation receivers is integrated as a function of time to obtain an integration value; and said obtained integration value is evaluated at the moment when the integral of the signal of the comparison radiation receiver has reached a predetermined level.
Claim 45
Dependent Claim
58 words
The smoke detector as defined in claim 2, wherein: said evaluation circuit is structured such that at an alarm point said output signal, lies between 0.01 and 0.2, wherein a and b are selected such that a I R /I RV =1 and b I G /I GV =1, when no smoke is present in said measuring path.
Claim 46
Dependent Claim
186 words
The smoke detector as defined in claim 1, wherein: said evaluation circuit is constructed such that it forms an output signal; said evaluation circuit forming said output signal in response to a portion of the radiation from said radiation transmitter for emitting radiation in a longer wave spectral region and from said radiation transmitter for emitting radiation in a shorter wave spectral region which has passed through said measuring path in response and to a portion of said radiation which has passed through said comparison path according to the function: ##EQU11## wherein: C=said output signal; a=a first predeterminate device coefficient of the evaluation circuit; b=a second predeterminate device coefficient of the evaluation circuit; I R =intensity of said radiation received in said longer wave spectral region by said measuring radiation receiver; I RV =intensity of said radiation received in said longer wave spectral region by said comparison radiation receiver; I G =intensity of said radiation received in said shorter wave spectral region by said measuring radiation receiver; and I GV =intensity of said radiation received in said shorter wave spectral region by said comparison radiation receiver.
Claim 47
Dependent Claim
185 words
The smoke detector as defined in claim 1, wherein: said evaluation circuit is constructed such that it forms an output signal; said evaluation circuit forming said output signal in response to a portion of the radiation from said radiation transmitter for emitting radiation in a longer wave spectral region and from radiation transmitter for emitting radiation in a shorter wave spectral region which has passed through said measuring path and in response to a portion of said radiation which has passed through said comparison path according to the function: ##EQU12## wherein: D=said output signal; a=a first predeterminate device coefficient of the evaluation circuit; b=a second predeterminate device coefficient of the evaluation circuit; I R =intensity of said radiation received in said longer wave spectral region by said measuring radiation receiver; I RV =intensity of said radiation received in said longer wave spectral region by said comparison radiation receiver; I G =intensity of said radiation received in said shorter wave spectral region by said measuring radiation receiver; and I GV =intensity of said radiation received in said shorter wave spectral region by said comparison radiation receiver.
Claim 48
Dependent Claim
62 words
The smoke detector as defined in claim 2, wherein: said evaluation circuit is constructed such that in addition there is formed the magnitude: ##EQU13## wherein: F=a parameter dependent upon the type of smoke present; d=a third predeterminate device coefficient of the evaluation circuit; e=a fourth predeterminate device coefficient of the evaluation circuit; and f=a fifth predeterminate device coefficient of the evaluation circuit.
Claim 49
Dependent Claim
33 words
The smoke detector as defined in claim 47, wherein: said evaluation circuit is constructed such that at least one of said predeterminate device coefficients a, b, d, e and f is gradually adjustable.
Claim 50
Dependent Claim
44 words
The smoke detector as defined in claim 2, wherein: said evaluation circuit is constructed such that in addition there is formed the magnitude: ##EQU14## wherein: H=a parameter dependent upon the type of smoke present; and h=a third predeterminate device coefficient of the evaluation circuit.
Claim 51
Dependent Claim
31 words
The smoke detector as defined in claim 49, wherein: said evaluation circuit is constructed such that at least one of said predeterminate device coefficients a, b and h is gradually adjustable.
Claim 52
Dependent Claim
40 words
The smoke detector as defined in claim 47, wherein: said evaluation circuit comprises circuit means for forming a mean value of said output signal; and said evaluation circuit is constructed for comparing said output signal to said mean value thereof.
Claim 53
Dependent Claim
40 words
The smoke detector as defined in claim 49, wherein: said evaluation circuit comprises circuit means for forming a mean value of said output signal; and said evaluation circuit is constructed for comparing said output signal to said mean value thereof.
Claim 54
Dependent Claim
35 words
The smoke detector as defined in claim 45 or 46, wherein: said circuit being constructed so that there is additionally formed the time-differentiated quotient dC/dt or dD/dt of the respective output signal C or D.
Claim 55
Dependent Claim
44 words
The smoke detector as defined in claim 1, wherein: said two radiation transmitters are mutually adjacently arranged in the direction of the radiation; and a bifocal Fresnel lens being provided for imaging the radiation of said two radiation transmitters onto the same image spot.
Claim 56
Dependent Claim
56 words
The smoke detector as defined in claim 3, wherein: said evaluation circuit is structured such that at an alarm point said output signal lies between 0.01a and 0.2a, wherein a and b are selected such that a(I R /I RV )=1 and b(I G /I GV )=1, when no smoke is present in said measuring path.
Claim 57
Dependent Claim
56 words
The smoke detector as defined in claim 45, wherein: said evaluation circuit is structured such that at an alarm point said output signal lies between 0.01b and 0.2b, wherein a and b are selected such that a(I R /I RV )=1 and b(I G /I GV )=1, when no smoke is present in said measuring path.
Claim 58
Dependent Claim
56 words
The smoke detector as defined in claim 46, wherein: said evaluation circuit is structured such that at an alarm point said output signal lies between 0.005a and 0.la, wherein a and b are selected such that a(I R /I RV )=1 and b(I G /I GV )=1, when no smoke is present in said measuring path.
Claim 59
Dependent Claim
43 words
The smoke detector as defined in claim 45 or 46, wherein: the evaluation circuit contains predetermined circuit components connected to said comparison radiation receiver and selected such that in the absence of smoke in said measuring path said output signal is essentially zero.
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) | 1988-10-14 | 1989-04-15 | 1989-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-14 | 1993-04-15 | 1993-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-14 | 1997-04-15 | 1997-10-15 | $7700.00 | Window Closed / Lapsed |