US3417392A - Fire detector - Google Patents

Description

Dec. 17, 1968 J. E. HANSEN, SR., ET AL FIRE DETECTOR Filed OGt. 23, 1965 UW''QRS` JUL /A/V E HANSEN Sl?. BY JUL /A/V E HANSEN di?.

ATTORNE Y United States Patent O 3,417,392 FIRE DETECTOR Julian E. Hansen, Sr., 6142 Loukelton Circle, San Diego,

Calif. 92120 and Julian E. Hansen, Jr., 7025 Boulevard Drive #5, La Mesa, Calif. 92041 Filed Oct. 23, 1965, Ser. No. 503,421 8 Claims. (Cl. 340-409) ABSTRACT F THE DISCLOSURE A smoke detector having a cylindrical housing for shielding ambient light with a lighted light bulb located within the housing and a light collimating lens system positioned in front of the light, a light-sensitive transducer located Within the housing in proximity to the collimated light, an air intake in the housing with -a light absorbing mesh in proximity with the air intake, an air pump between the light absorbing mesh and the air intake, an exhaust located on the other side of the light-sensitive transducer from the air intake, an electronic indicating threshold detector connected to the light-sensitive transducer for indicating relative intensity of light impinging on the transducer and a monitoring light-sensitive transducer positioned within the housing and in the light path for indicating the condition of the light source.

The present invention relates to a fire detector, and lmore particularly to a fire detector for detecting changes in both ambient smoke and temperature.

Prior art devices for detecting smoke have had serious limitations due to excessive cost and bulk, resulting from complicated mechanisms and circuitry associated therewith. According to the invention, these diiiiulties have been overcome by the utilization of a concise mechanism for detecting smoke which is inserted into a small circular cylinder. In the center portion of the cylinder, a light source and suitable focusing lens are employed to produce a narrowly defined light beam therein, which travels in proximity to a light sensitive means, such as a photocell. At one end of the cylinder, a filter is provided, allowing air (and smoke) to enter through a light bafiie to lthe area of the light beam. The air is brought in through a novel air pump system, and passed through a light absorbing assembly for controlling the amount of reflection from the beam that could pass back to the light sensitive means. When smoke enters the area of the beam, a certain almount of light will be refiected, depending upon smoke density, and hence a certain amount of light will impinge upon the light sensitive means, changing its resistance accordingly.

At the other end of the cylinder, electronic circuitry is provided for sensing the change of resistance of the light sensitive means and relaying this information to suitable indicating means.

Other novel features of the smoke detector comprise the provision of -a monitoring light sensitive means placed in the normal path of the light beam for energizing a monitoring light, indicating a large portion of the system being operational. Another novel feature is in a novel test means by which an obstruction is placed in the light path, causing sufficient impingement upon the photo sensitive means, and giving an alarm indicating substantially the remainder of the systems normal operation.

An object of the present invention is the provision of a fire detector for detecting changes in ambient levels of smoke and temperature.

Another object is to provide a fire detector in which the sensing elements and their associated circuitry is conveniently packaged in a small cylindrical housing.

A further object of the invention is the provision of a fire detector in which the sensing elements and their asso- ICC ciated circuitry can be conveniently checked in both a normal and a fire condition.

A still further object of the invention is the provision of a fire detector which is simple to construct, relatively inexpensive, and requires a minimum of maintenance and adjustment.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof and wherein:

FIG. 1 is a side sectional View of the mechanical layout of the present invention;

FIG. 2 is a sectional View of FIG. 1 `taken along lines 2 2 of FIG. l; and

FIG. 3 is a schematic illustration of the electronic circuitry of the present invention.

Referring to FIG. l, cylindrical housing 11 has insulator retaining disc 12 having wire apertures 13 and 14 therein. Circuit board 16 abuts retaining disc 12 and light mounting block 17. Light 18 is carried by light mounting block 17 and is located on the longitudinal axis of housing 11. Reflector 19 surrounds lamp 18 and focuses light from lamp 18 along the longitudinal axis of cylindrical housing 11. Lens 21 and 22 and bafiies 23, 24, 25 and 26 focus the reiiected light from reflector 19 into a sharp beam indicated by dotted lines 27, and having its focal point along an axis defined by dotted line 28.

Photocell 31 is carried by mounting cylinder 32 which is mounted within cylindrical housing 11. Photocell 31 has light baffles 33 surrounding it. Mounting cylinder 36 carries light absorbing cylinders 37. Mounting section 38 abuts cylinder 36 and honeycomb section 37, carrying solenoid 39. Mounting section 38 has apertures 41 and 42 therein. Solenoid 39 carries mounting member 41 which, in turn, carries reed 42 and light bafiie 44. Mounting section 38 carries cylindrical light baffle 46.

Filter disc 47 is placed at an opposite end of cylindrical housing 11 from insulation wafer 12. Dotted lines 48 indicate an air path through filter 47 around light baffle 48 and into cylindrical light bafiie 46 through honeycomb light absorbing assembly 37 and into the light beam path 27. The exhaust of air is between lens system mounting filter 49 and mounting cylinder 51 through exhaust apertures 52.

FIG. 2 is a cross-sectional area taken along lines 2-2 of FIG. 1. Honeycombed sections 37 are shown carried by cylindrical mounts 36, which, in turn, are carried by honeycombed `sections 37. This structure is all mounted within cylindrical housing 11.

Referring to FIG. 3, terminals 61 are connected across Winding 62 of transformer T-1, having core 63 and secondary Winding 64. One side of secondary winding 64 is connected to common bus 66 which is in turn grounded, and the other terminal of secondary winding 64 is connected to diode 67, one side of light 68, one side of alarm solenoid 69, one side of solenoid L-1, and one side of diode 71, one side of capacitor C-2, and one side of diode D-1. The other side of solenoid 69 and light 68 are connected to stationary Contact 72 of solenoid 73. Movable contact 74 of solenoid 73 is connected to ground.

The other side of diode 71 is connected through capacitor 76 to common bus 66, to collector 77 of transistor Q-1 and through resistance 78 to base 79 of transistor Q-1. Base 79 of transistor Q-l is also connected through diode 81 to common bus 66. Emitter 82 of transistor Q-l is connected to positive DC bus 88.

The other side of diode 67 is connected through capacitor 91 to ground, and through solenoid 92 to photocell PC-3. The other side of photocell PC-3 is connected to ground. The junction of diode 67 and capacitor 91 is also connected through solenoid 73, and photocell 2 to ground.

Stationary contact 93 of solenoid 92 is connected through battery 94 and lamp 96 to movable contact 97 of solenoid 92. i

Switch S-l is connected between positive'DC bus 88 and one side ofA solenoid L-2. The other side of solenoid L-2 is grounded. Solenoid L-2 has a movable shutter'99 associated therewith. Dotted lines 101 indicate the position of movable shutter 99 when solenoid L-2 is actuated.

Positive DC bus 88 is connected through lamp M to ground, and through resistance R-l and temperature sensitive resistance T-l to common bus 66 to ground. The junction of resistance R-1 and temperature sensitive resistance T-1 is also connected through resistance R-2 and temperature sensitive resistance T-2 to ground. The junction of resistance T-2 and temperature sensitive resistance T-2 is connected to base 102 of transistor Q-2. Emitter 103 of transistor Q-2 is connected through resistance R-3 to positive DC bus 88. Collector'104 of transistor Q-2 is connected through resistance R-4 to ground.

One side of second winding 64 of transformer T-1 is also connected to AC bus 106. AC bus 106 is connected to a voltage tripler comprising diodes D-1, D-Z and D-3 and capacitors C-1, C-2 and C3. The output voltage of the voltage tripler is taken across capacitor C-3, one end of which is connected to ground, and the other side through resistance R-6 to positive bus 107. Diode D-4 is connected between positive bus 107 and ground, and neon bulb L-3 and resistance R-S are connected between ground and a junction of capacitor C-3 and diode D-3.

Neon bulb N-3 is connected from ground through resistance R-S across capacitor C-3, as is diode D-4 connected from ground through resistance R-6 across capacitor C-3. The junction of diode D-4 and resistance R-6 is connected to positive bus 107.

Collector 104 of transistor Q2 is also connected through resistances R-7 and R-8, photo sensitive resistance PC-l to positive bus 107. Neon bulb NE-l and resistance R-9 are connected across resistance R-7 and R-S in serial relationship.

Positive bus 107 is also connected through temperature sensitive resistance T-3, resistance R12, and resistance R-11 to ground. Neon bulb N-2 and resistance R- 10 are connected to cross resistances R-11 and R-12 in serial relationship. Neon bulbs N-l and N-2 are mounted in physical proximity to photo sensitive element 'TC-1.

Lens assembly 108 consists of the lenses 21 and 22 and light baffles 23, 24, and 26 of FIG. 1, and is shown mounted in physical proximity to light 18, having light beam 27 emitting therefrom into light absorbing assembly shown as block 37 schematically. Light sensitive resistance PC-3 is shown on the other side of light absorbing assembly 37, receiving a portion 27A of light beam 27.

Operation Referring back to FIG. l, power leads are applied to apertures 13 and 14 to supply the necessary power to circuit board 16 and light 18. The output from this system is also taken through apertures 13 and 14 to the alarm unit. Quiescently, with little or no smoke in the ambient atmosphere in which the unit is placed, solenoid 39 is energized, causing reed 42 to vibrate, which in turn pumps air through filter 47, and, following dotted lines 48, around light baille 44 through aperture 40 in wafer mount 41 and light absorbing honeycomb assembly 37 into light path 27 and on out through exhaust apertures 52. At this time a light beam from light 18 passes through light baflles 23, 24, 25 and 26, and lenses 21 and 22, forming a beam having its focal plane at dotted line 28 substantially over light sensitive device PC-l which can be a suitable photocell. Light baflles 33 surrounding light sensitive dcvice PC-l prevent any reflected light from Within housing 11 from reaching the light sensitive means PC-1, so that in an ambient condition a negligent amount of light will impinge uponlight sensitive means PC-1. Light absorbing honeycomb assembly.` 37 furtherdecreases the possibility :of reection, by their geometric configuration.

At this time, however, a certain amount of light will pass through the honeycomb assembly 37 and mounting wafer 41 to another light-sensitive means, PC-3, which also can be a photocell. This light impinging upon light lsensitive-means .PC-3 will yield an indication that much of the system, iet, the lighting system is operable. Solenoid 12 and movable contact aa 4will be explained with reference to FIG.-3.

-When smoke is presentin the ambient atmosphere surrounding housing 11, smokefwill be pulled through vclust lter 47 4byvibrating reed 42, and follow the same path into light beam 27. The smoke particles will then cause a certainl amount of reflected light to impinge upon |light sensitive means PC-1. Naturally, the higher the density of the smoke, the more light will be reflected, and the more light-sensitive device PC-l will be affected. When a predetermined level of smoke is reached and light sensitive means PC-l is thus affected a predetermined amount, circuitry in circuit board 16 will send a signal to lsuitable alarm means, indicating excessive smoke in the area. Electrical wires from light-sensitive means PC-l and PC-3 are taken through mounting rods (not shown) to circuit board 16.

FIG. 2 merely shows a sectional view of honeycomb section 37 taken along lines 2-2 of FIG. l. This is deemed to be self-explanatory, and no further explanation will be given.

Referring to FIG. 3, the electronics of the system. is shown in schematic form. The parts to the left of dotted Aline 10 can be remotely mounted in a power supply and alarm unit, while the parts to the right of dotted line 10 are mounted on the circuit board 16 (FIG. 1), and of course, the two light-sensitive means PC-l and PC-3 .are located within the housing 11, external to the circuit board.

Terminals 61 are connected to any convenient source of AC power such as 117 volts AC, energizing primary winding 62 of transformer T-1. Secondary winding 64 of transformer T-l is applied across a rectifier comprising diode 71 and capacitor 76. A series regulator Q-1 with its associated components, resistance 78 and Zener diode 81, supply a regulated DC voltage on bus S8. An AC voltage is taken on bus 106 which is the full secondary voltage of transformer T-l with respect to ground, and a grounded lead 66 is taken a reference output of the power supply.

AC line 106 is applied across a voltage tripler comprising diodes D-l, D-2, D-3 and capacitances C-l, C-2 and C-3. This voltage is applied through series resistance R-6 to bus 107, which supplies the input voltage to the temperature sensing and smoke detecting elements P-3 and PC-l respectively. Zener diode D-4 regulates this input voltage. Temperature sensitive resistance T-3 is in series with R'-11 and' R-12 between DC bus 107 and ground. At the junction of R-12 and T-3, a resistance R-13 and neon bulb are taken in series to ground. Quiescently, neon bulb N-2 is below its firing potential, and as temperature increases, the resistance of T-3 decreases to the point where the voltage at the junction of R-12 and T-3 will ignite neon bulb N-2. When this happens, the light from neon bulb N-2 impinges Iupon light sensitive resistance PC-2, decreasing its resistance and energizing solenoid 73. When contacts 72 and 74 of solenoid 73 close, visual and audio alarms 68 and 69 respectively are energized, indicating a probable fire. Neon bulb N-3 supplies sufficient ambient light to insure the ignition of neon bulbs N-1 and N-Z.

Likewise, when light impinges on light sensitive resistance PC-l, the voltage at the junction of R-8 and PC-l will increase, due to the decrease of resistance of PC-l, to a point where neon bulb N-l will ignite, causing the same indication of visual and audio alarms 68 and 69.

Since light sensitive resistances such as photocells are also temperature sensitiveA it becomes necessary to compensate for temperature variations to enable a smoke detector to operate at the same level of ambient smoke, regardless of changes in ambient temperature. Transistor Q-2 and its associated circuitry accomplished this. In the base circuit of transistor Q-Z, two temperature sensitive resistances, T-1 and T-2 are placed in series with resistances R-l and R-2 respectively, which will vary the bias on transistor Q2 with a change in temperature changing the voltage at the collector 104 of transistor Q-2, which is the reference potential applied to the smoke detecting circuitry of neon bulb N-l, light sensitive resistance PC-l and their associated resistors An operation test of the smoke detecting circuit is provided by actuating solenoid L-2 through switch S-1 and moving its movable contact 99 into the dotted line position shown at 101. This will interrupt light beam 27, causing light to impinge upon light sensitive resistance PC-l, causing energization of the tire alarm through the smoke detecting system.

It should be understood, of course, that the foregoing disclosure relates to only a preferred embodiment of the invention, and that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purposes of the disclosure which do not constitute departures from the spirit and scope of the invention.

What is claimed is:

1. A iire detector comprising:

a housing for shiel-ding ambient light;

a light source positioned within said housing, said light source generating a predetermined light beam;

a light-sensitive means positioned within said housing in proximity to said light beam;

an air intake in said housing;

a light bathe positioned within said housing between said air intake and said light-sensitive means;

an air pump positioned within said light baffle;

a light absorbing means positioned within said housing between said light sensitive means and said light baffle to limit any reflections from said light source;

indicating means connected to said light-sensitive means for indicating relative intensity of light impin ging thereon; and

a light monitoring means positioned within said housing and in proximity with `said light path.

2. The re detector referred to in claim 1, and further including a temperature sensing means operably connected to said indicating means.

3. The lire detector referred to in claim 1 wherein said indicating means comprises:

a first light in :serial relationship with said light sensitive means;

a second light operably connected to said temperature sensing means;

a photocell in proximity to said lirst and second lights;

and

an alarm system connected to said photocell for actuation thereby.

4. The tire detector of claim 1, wherein said housing is cylindrical.

5. A fire detector comprising:

a housing for shielding ambient light;

a light source positioned within said housing, said light source generating a predetermined light beam;

a light sensitive means positioned within said housing in proximity to said light beam;

an air intake in said housing;

a light bathe positioned within said housing between :said air intake and said light sensitive means;

an air pump positioned within said light baffle;

a light absorbing means positioned within said housing between said light sensitive means and said light bai-lie to limit any reflections from said light source;

indicating means connected to said light sensitive means for indicating relative intensity of light impinging thereon; and

testing means positioned within said housing and in proximity to said light beam, said testing means operable when actuated to reect a portion of said light beam to impinge upon said light sensitive means.

6. The ire detector of claim 5, and further including a temperature sensing means operably connected to said indicating means.

7. The fire detector of claim 5, wherein said indicating means comprises:

a irst light in serial relationship with said light senstive means;

a second light operably connected to said temperature sensing means;

a photocell in proximity to said rst and second lights;

and

an alarm system connected to said photocell for actuation thereby.

8. The lire detector of claim 5, wherein said housing is cylindrical.

References Cited UNITED STATES PATENTS 2,185,361 1/1940 Towne 340-228 X 3,255,441 6/1966 Goodwin et al. 340-227 X 3,314,058 4/1967 Osborne 340-228 JOHN W. CALDWELL, Primary Examiner.

D. L. TRAFTON, Assistant Examiner.

U.S. Cl. X.R.

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