US5420440A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical obscruation smoke monitor having a shunt flow path located between two access ports
Assignee: REL-TEK Corp
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Filing: 1994-02-28
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Granted: 1995-05-30
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Expires: 2014-02-28
Abstract
Abstract An obscuration type optical smoke monitor is provided for use particularly in dusty and dirty environments. The smoke monitor comprises a housing enclosing a smoke monitoring chamber; two access ports located opposite each other on the housing; a shunt air flow path located between said two access ports; means to conduct air from said access ports through an optical chamber; a light emitting diode at the first end of said optical chamber, which light emitting diode produces a light beam axially through the center of said optical chamber; a photo transistor at the second end of said optical chamber to receive the light bean and issue an electrical signal proportional to the received light intensity; and an electronic module which provides variable electronic output, generating an analog output essentially proportional of the optical obscuration caused by the smoke. Baffle means are provided to minimize extraneous light scattering from dust and dirt in the air,
Inventors
- 👤 Albert E. Ketler
- 👤 Christopher Kolesar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:41
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/47; G01N21/49; G01N21/53; G01N21/534; G08; G08B; G08B17/00; G08B17/10; G08B17/103; G08B17/11; G08B17/113
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
130 words
An optical smoke monitor comprising a housing enclosing a smoke monitoring chamber; two access ports located opposite each other on the housing; a shunt flow path located between said two access ports; means to conduct air from said access ports vertically upwardly to an optical chamber having a first end and a second end; a light source at the first end of said optical chamber, which light source produces a light beam axially through of said optical chamber; radiation sensing means at the second end of said optical chamber to receive the light beam and issue an electrical signal proportional to the received light intensity to an electronic module; whereby the electronic module provides variable electronic output, generating an output essentially proportional to the optical obscuration caused by the smoke.
Claim 2
Dependent Claim
130 words
An optical smoke monitor comprising a housing enclosing a smoke monitoring chamber; two access ports located opposite each other on the housing; a shunt flow path located between said two access ports; means to conduct air from said access ports vertically upwardly to an optical chamber having a first end and a second end; a light source at the first end of said optical chamber, which light source produces a light beam axially through of said optical chamber; radiation sensing means at the second end of said optical chamber to receive the light beam and issue an electrical signal proportional to the received light intensity to an electronic module; whereby the electronic module provides variable electronic output, generating an output essentially proportional to the optical obscuration caused by the smoke.
Claim 3
Dependent Claim
66 words
The optical smoke monitor according to claim 1 wherein a second radiation sensing means is located near said first end of said optical chamber to monitor the optical intensity of the light beam emitted from the light source and connected to electronic circuitry; and the electronic circuitry receives a signal from said second radiation sensing means and controls the current to maintain a constant light level.
Claim 4
Dependent Claim
18 words
The optical smoke monitor according to claim 1 wherein optical baffle means are provided within the optical chamber.
Claim 5
Dependent Claim
18 words
The optical smoke monitor according to claim 3 wherein said baffle means have the form of half disks.
Claim 6
Dependent Claim
19 words
The optical smoke monitor according to claim 3 wherein said baffle means are in the configuration of an accordion.
Claim 7
Dependent Claim
37 words
The optical smoke monitor according to claim 1 further including a right vertical flow stack at the right side of said optical chamber and a left vertical flow stack at the left side of said optical chamber.
Claim 8
Dependent Claim
32 words
The optical smoke monitor according to claim 6 wherein said right vertical flow stack is provided with a closure device and said left vertical flow stack is provided with a closure device.
Claim 9
Dependent Claim
17 words
The optical smoke monitor according to claim 7 wherein each said closure device is a friction-fit cap.
Claim 10
Dependent Claim
57 words
The optical smoke monitor according to claim 7 wherein a filter is attached to the closure device of said right flow stack whereby moving said closure device 90 degrees to a calibrate position indicated with a label places said filter directly into the light beam of said first photo receiver whereby a reduced light level is indicated.
Claim 11
Dependent Claim
23 words
The optical smoke monitor according to claim 1 further including an amplifier voltage reference means to monitor voltage output of the electronic circuitry.
Claim 12
Dependent Claim
17 words
The optical smoke monitor according to claim 1 wherein the light source is a light emitting diode.
Claim 13
Dependent Claim
17 words
The optical smoke monitor according to claim 1 wherein the radiation sensing means is a photo transistor.
Claim 14
Dependent Claim
34 words
The optical smoke monitor according to claim 1 wherein the zero setting of an amplifier for the radiation sensing means is the voltage when there is no smoke or dust in the optical chamber.
Claim 15
Dependent Claim
38 words
The optical smoke monitor according to claim 1 further including a second radiation sensing means and located in close proximity to said light source and compensation circuit means for maintaining a constant intensity output of said second photoreceiver.
Claim 16
Dependent Claim
35 words
The optical smoke monitor according to claim 1 further including means to receive the analog output from the electronic module, which means to receive the analog output is located remote from the optical smoke monitor.
Claim 17
Dependent Claim
20 words
The optical smoke monitor according to claim 1 further including detection circuitry to monitor the level of said analog output.
Claim 18
Dependent Claim
23 words
The optical smoke monitor according to claim 16 wherein said detection circuitry is set from a location remote from said optical smoke monitor.
Claim 19
Dependent Claim
40 words
The optical smoke monitor according to claim 1 wherein said shunt flow path and said two access ports are attached to said housing in such a way that the shunt flow path and two access ports can be rotated downwardly.
Claim 20
Dependent Claim
46 words
The optical smoke monitor according to claim 1 wherein each of said two access ports expand immediately inside said ports to about double the diameter of each of aid two access ports to reduce the velocity of air flowing into each of said two access ports.
Claim 21
Dependent Claim
21 words
The optical smoke monitor according to claim 1 further including an external monitor for the electronic output from the electronic module.
Claim 22
Dependent Claim
34 words
The optical smoke monitor according to claim 20 wherein said external monitor generates alarms signals at a predetermined threshold and said external monitor is selected from the group consisting of meters, recorders, and computers.
Claim 23
Dependent Claim
15 words
The optical smoke monitor according to claim 21 wherein said predetermined threshold is 5% obscuration.
Claim 24
Dependent Claim
20 words
The optical smoke monitor according to claim 1 wherein said electronic module contains detection means for activating an alarm means.
Claim 25
Dependent Claim
24 words
The optical smoke monitor according to claim 23 wherein said alarm means is selected from the group consisting of horns, bells, and strobe lights.
Claim 26
Dependent Claim
38 words
The optical smoke monitor according to claim 1 including four potentiometers to set the intensity of the light source, to balance the radiation sensing means, to adjust a zero smoke setting an to adjust a full scale setting.
Claim 27
Dependent Claim
20 words
The optical smoke monitor according to claim 1 further comprising a dust plug for each of said two access ports.
References Cited (Backward Citations)
US3500450A
Cited
US3544218A
Cited
US3708675A
Cited
US3976891A
Cited
US4129383A
Cited
US4099065A
Cited
US4269510A
Cited
US4384488A
Cited
US4543815A
Cited
US4906978A
Cited
US5021677A
Cited
US5170150A
Cited
US5247283A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-05-29 | 1998-11-28 | 1999-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-05-29 | 2002-11-28 | 2003-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-05-29 | 2006-11-28 | 2007-05-30 | $7700.00 | Window Closed / Lapsed |