US4623788A — Fiber optic system with self test used in fire de…

Claim 1

Independent Claim 193 words

A test apparatus for testing a fire detection system incorporating fiber optics between a detector coupled to a proximal end of a fiber optics element and a light pickup coupled to the distal end of said element, the test apparatus comprising: a reflective/transmissive member mounted at the distal end of the fiber optics element for reflecting light reaching the member from the fiber optics element while passing light directed in the opposite direction into the fiber optics element; a light source mounted adjacent to the detector for emitting a light pulse to be injected into the fiber optics element in the direction of the reflective/transmissive member; means for coupling light pulses from the light source into the fiber optics element adjacent the proximal end and directing them toward said member while passing light in an opposite direction along the fiber optics element from said member toward the detector; and means for selectively controlling the light source to emit light pulses in order to test the integrity of the fire detection system whereby light from the source is reflected by said member back to the detector through the fiber optics element during the test.

Claim 2

Dependent Claim 193 words

A test apparatus for testing a fire detection system incorporating fiber optics between a detector coupled to a proximal end of a fiber optics element and a light pickup coupled to the distal end of said element, the test apparatus comprising: a reflective/transmissive member mounted at the distal end of the fiber optics element for reflecting light reaching the member from the fiber optics element while passing light directed in the opposite direction into the fiber optics element; a light source mounted adjacent to the detector for emitting a light pulse to be injected into the fiber optics element in the direction of the reflective/transmissive member; means for coupling light pulses from the light source into the fiber optics element adjacent the proximal end and directing them toward said member while passing light in an opposite direction along the fiber optics element from said member toward the detector; and means for selectively controlling the light source to emit light pulses in order to test the integrity of the fire detection system whereby light from the source is reflected by said member back to the detector through the fiber optics element during the test.

Claim 3

Dependent Claim 32 words

The apparatus of claim 1 further including means for responding to signals from the detector corresponding to said light pulses to provide a signal indicating the condition of the fire detection system.

Claim 4

Dependent Claim 23 words

The apparatus of claim 1 wherein the reflective/transmissive member comprises a dichroic mirror having its reflective surface directed toward the fiber optics element.

Claim 5

Dependent Claim 25 words

The apparatus of claim 1 wherein the light pickup comprises a lens mounted to focus light on the distal end of the fiber optics element.

Claim 6

Dependent Claim 23 words

The apparatus of claim 4 wherein the reflective/transmissive member is mounted between the lens and the distal end of the fiber optics element.

Claim 7

Dependent Claim 30 words

The apparatus of claim 1 wherein the reflective/transmissive member comprises a bandpass filter configured to transmit light having wavelengths within a predetermined range and to reflect light at other wavelengths.

Claim 8

Dependent Claim 22 words

The apparatus of claim 6 wherein the bandpass filter is configured to transmit light having a wavelength between 1.3 and 1.55 microns.

Claim 9

Dependent Claim 25 words

The apparatus of claim 7 wherein the light source comprises a light emitting diode emitting light, when energized, at a wavelength of approximately 0.9 microns.

Claim 10

Dependent Claim 53 words

The apparatus of claim 1 wherein the fiber optics element comprises a bundle of individual optical fibers arranged in a flexible cable, at least one of said fibers being coupled between the light source and the reflective/transmissive member, and wherein the remainder of said fibers are coupled between said member and the detector.

Claim 11

Dependent Claim 21 words

The apparatus of claim 1 wherein the fiber optics element includes a combiner having a branch coupled to the light source.

Claim 12

Dependent Claim 38 words

The apparatus of claim 10 wherein the combiner comprises a principal fiber for transmitting light in both directions and an auxiliary fiber affixed to the principal fiber for coupling light from the light source into the principal fiber.

Claim 13

Dependent Claim 234 words

A fire detection system comprising: a detector coupled to fire responsive means for generating a signal to energize said means in response to light received from a fire; a fiber optics element coupled to the detector and adapted to extend into a remote location where fire is to be detected for transmitting light to the detector from the vicinity of a fire; a reflective/transmissive member mounted at a distal end of the fiber optics element for reflecting light reaching the member from the fiber optics element while passing light directed in the opposite direction into the fiber optics element; a light source mounted adjacent the detector for emitting a light pulse to be injected into the fiber optics element in the direction of the reflective/transmissive member; means for coupling light pulses from the light source into the fiber optics element adjacent the proximal end and directing them toward said member while passing light along the fiber optics element from said member toward the detector; and means for selectively controlling the light source to emit light pulses in order to test the integrity of the fire detection system whereby light from the source is reflected by said member back to the detector through the fiber optics element during the test, and fire responsive means coupled to the detector for responding to the detection of light directed into the fiber optics element through the reflective/transmissive member.

Claim 14

Dependent Claim 234 words

A fire detection system comprising: a detector coupled to fire responsive means for generating a signal to energize said means in response to light received from a fire; a fiber optics element coupled to the detector and adapted to extend into a remote location where fire is to be detected for transmitting light to the detector from the vicinity of a fire; a reflective/transmissive member mounted at a distal end of the fiber optics element for reflecting light reaching the member from the fiber optics element while passing light directed in the opposite direction into the fiber optics element; a light source mounted adjacent the detector for emitting a light pulse to be injected into the fiber optics element in the direction of the reflective/transmissive member; means for coupling light pulses from the light source into the fiber optics element adjacent the proximal end and directing them toward said member while passing light along the fiber optics element from said member toward the detector; and means for selectively controlling the light source to emit light pulses in order to test the integrity of the fire detection system whereby light from the source is reflected by said member back to the detector through the fiber optics element during the test, and fire responsive means coupled to the detector for responding to the detection of light directed into the fiber optics element through the reflective/transmissive member.

Claim 15

Dependent Claim 32 words

The system of claim 12 further including means for responding to signals from the detector corresponding to said light pulses to provide a signal indicating the condition of the fire detection system.

Claim 16

Dependent Claim 23 words

The system of claim 12 wherein the reflective/transmissive member comprises a dichroic mirror having its reflective surface directed toward the fiber optics element.

Claim 17

Dependent Claim 22 words

The system of claim 12 further including a lens mounted to focus light on the distal end of the fiber optics element.

Claim 18

Dependent Claim 23 words

The system of claim 15 wherein the reflective/transmissive member is mounted between the lens and the distal end of the fiber optics element.

Claim 19

Dependent Claim 49 words

The system of claim 12 further including built-in test equipment control apparatus for selectively energizing the light source and for diverting the light detection signal from the detector away from the fire responsive means and applying said signal to provide an indication of operability for the system under test.

Claim 20

Dependent Claim 59 words

The apparatus of claim 17 comprising a plurality of fire detection branches, each including a detector, a fiber optics element, a reflective transmissive member, a light source, and said light coupling means, the built-in test equipment control means being coupled to said branches to selectively test the integrity of each branch when operating in the built-in test equipment mode.

Claim 21

Dependent Claim 26 words

The system of claim 18 wherein each reflective/transmissive member comprises a bandpass filter configured to transmit light having a wavelength between approximately 1.3 and 1.5 microns.

Claim 22

Dependent Claim 25 words

The system of claim 19 wherein each light source comprises a light emitting diode emitting light, when energized, at a wavelength of approximately 0.9 microns.

Claim 23

Dependent Claim 13 words

The system of claim 18 wherein each reflective/transmissive member comprises a dichroic mirror.

Claim 24

Dependent Claim 13 words

The system of claim 15 wherein the lens is a miniature self-focusing lens.

Claim 25

Dependent Claim 23 words

The system of claim 12 wherein the reflective/transmissive member comprises a shaped terminating element at the distal end of the fiber optics element.

Claim 26

Dependent Claim 39 words

The system of claim 23 wherein the terminating element comprises the end of the fiber optics element lapped and polished to develop an internal reflective surface which is detectably more reflective than the end of a broken optical fiber.

Claim 27

Dependent Claim 212 words

Test apparatus for testing a fire detection system incorporating fiber optics comprising: at least one fiber optics element having a pair of opposite ends, the distal end of the element being adapted to pick up light from a fire; a detector coupled to the proximal end of the fiber optics element for generating an output signal in response to light received over the fiber optics element; partially reflective means at the distal end of the fiber optics element for reflecting at least a portion of light reaching said means from the fiber optics element while passing light directed in the opposite direction into the fiber optics element, said means providing a level of reflectivity for light received along the fiber optics element which is detectably higher than the level of reflectivity normally presented by a broken fiber end; a light source coupled to the fiber optics element adjacent the proximal end thereof for emitting a light pulse into the fiber optics element in the direction of said means; and control circuitry for selectivity controlling the light source to emit light pulses and coupled to receive output signals from the detector corresponding to the reflection of said light pulses by said means in order to test the integrity of the fire detection system.

Claim 28

Dependent Claim 212 words

Test apparatus for testing a fire detection system incorporating fiber optics comprising: at least one fiber optics element having a pair of opposite ends, the distal end of the element being adapted to pick up light from a fire; a detector coupled to the proximal end of the fiber optics element for generating an output signal in response to light received over the fiber optics element; partially reflective means at the distal end of the fiber optics element for reflecting at least a portion of light reaching said means from the fiber optics element while passing light directed in the opposite direction into the fiber optics element, said means providing a level of reflectivity for light received along the fiber optics element which is detectably higher than the level of reflectivity normally presented by a broken fiber end; a light source coupled to the fiber optics element adjacent the proximal end thereof for emitting a light pulse into the fiber optics element in the direction of said means; and control circuitry for selectivity controlling the light source to emit light pulses and coupled to receive output signals from the detector corresponding to the reflection of said light pulses by said means in order to test the integrity of the fire detection system.

Claim 29

Dependent Claim 43 words

The apparatus of claim 25 wherein said control circuitry includes means for distinguishing between output signals from the detector corresponding to reflected light from the light source and light from a fire picked up by the distal end of the fiber optics element.

Claim 30

Dependent Claim 14 words

The apparatus of claim 25 wherein the partially reflective means comprise a dichroic mirror.

Claim 31

Dependent Claim 25 words

The apparatus of claim 27 further including a lens for focusing light from a fire through the dichroic mirror and into the fiber optics element.

Claim 32

Dependent Claim 26 words

The apparatus of claim 25 wherein said means comprise a plano-convex lens having a partially reflective surface facing the distal end of the fiber optics element.

Claim 33

Dependent Claim 38 words

The apparatus of claim 25 wherein said means comprise the distal end of the fiber optics element lapped and polished to develop an increased level of reflectively relative to the reflectivity of a broken end of a fiber.

Claim 34

Dependent Claim 40 words

The apparatus of claim 25 wherein said means comprise a bead of epoxy affixed to said distal end and lapped and polished to develop an increased level of reflectivity relative to the reflectivity of a broken end of a fiber.

Claim 35

Dependent Claim 36 words

The apparatus of claim 25 further including fire suppressant means for extinguishing a fire detected by said detector, said fire suppressant means being coupled to said control circuitry and responsive to a fire detection signal therefrom.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1989-11-17	1990-05-19	1990-11-18	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1993-11-17	1994-05-19	1994-11-18	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1997-11-17	1998-05-19	1998-11-18	$7700.00	Window Closed / Lapsed

Fiber optic system with self test used in fire detection

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