Abstract:
An automated fire extinguishing apparatus includes a turret with a nozzle connected to a water supply. A plurality of sensors are used to detect a fire monitored by the apparatus. The signals from the sensors are used to aim the nozzle toward the fire and to initiate water ejection therefrom. After the fire is extinguished the water is turned off.

Description:
CROSS- REFERENCE TO RELATED APPLICATION    
     
       This reissue application is a continuation of U.S. patent application Ser. No.  09 / 137 , 960 , filed Aug.  20 ,  1998 , now U.S. Pat. No. RE  37 , 493 , which was a reissue of U.S. Pat. No.  5 , 548 , 276 , which resulted from U.S. patent application Ser. No.  08 / 158 , 989 . 
     
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     This invention pertains to an automatic fire extinguishing apparatus, and more particularly to an apparatus which locates a fire in a room and directs a stream of water or other agent from a nozzle at the fire for extinguishing it. 
     2. Description of the Prior Art 
     Automatic sprinkler installation are common in both residential and commercial establishments and are frequently mandated by local fire codes. However these sprinkler installations consist merely of a plurality of water nozzles set off by mechanical heat sensors. Because these types of heat sensors are slow and inefficient, by the time the fire is detected it has usually spread over a large area causing injuries and property damage before it is extinguished. Additionally, a fire is much more difficult to extinguish after it has spread then at its inception. Fire detectors are also known which detect a fire by using a heat and/or light sensors. However these types of detectors are used commonly merely to set off fire alarms and not to extinguish the fire itself. U.S. Pat. Nos. 3,665,440; 3,493,953; 3,689,773 and 3,824,392 show various state of the art detectors. 
     OBJECTIVES AND SUMMARY OF THE INVENTION 
     In view of the above-mentioned disadvantages of the prior art, it is an objective of the present invention to provide an apparatus which can quickly identify and extinguish a fire before it has a chance to spread. 
     A further objective is to provide an apparatus which can accurately pinpoint and extinguish a fire whereby the fire extinguishing activity is restricted only to the immediate vicinity of the fire thereby reducing damage. 
     A further objective is to provide a fire extinguishing apparatus which is reliable yet inexpensive. 
     Other objectives and advantages of this invention shall become apparent from the following description. 
     Briefly, the fire extinguishing apparatus constructed in accordance within invention contains a turret mounted to oversee a preselected area or room, and a plurality of sensors for sensing a fire. The apparatus also includes nozzle means disposed on the turret, and aiming means coupled to said sensors for aiming said nozzle means toward a fire detected by the sensors. An extinguishing agent is then ejected toward the fire by the nozzle means. After the fire has been extinguished, the flow of the extinguishing agent to the nozzle means is disrupted. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a side elevational view of a fire extinguishing apparatus constructed in accordance with this invention; 
         FIG. 2  shows a bottom view of the apparatus head showing the arrangement of the sensors and spray nozzle; 
         FIG. 3  shows a block diagram of one embodiment of the control circuit for the apparatus of  FIGS. 1 and 2 ; and 
         FIG. 4  shows a block diagram of an alternate embodiment of the control circuit. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, and more particularly  FIGS. 1 and 2 , an apparatus  10  constructed in accordance with this invention includes a base  12  mounted on a ceiling  14  and a turret  16 . The turret  16  includes a generally cylindrical housing  18  open at the top. A motor  20  secured inside housing  18  is used to rotate the turret  16  about a vertical axis X—X. For this purpose, motor  20  has a shaft  22  terminating in a toothed gear  24 . Base  12  is provided with a stationary ring  26  having radially inwardly extending teeth  28 . Teeth  28  engage gear  24  so that as the shaft  22  is turned by motor  20 , the turret  18  rotates with respect to the base. 
     An arm  30  is mounted on housing  18  by a horizontal shaft  32 . Shaft  32  also supports a toothed gear  34  disposed inside housing  18 . Also within housing  18  there is provided a second motor  36  with a shaft  38  and a gear  40 . Importantly, gear  40  has teeth  42  disposed at an angle and engaging the toothed wheel  34  such that as the gear  40  is turned by motor  36 , it causes a gear  34  and arm  30  to turn about shaft  32 . 
     At the tip of arm  30  there is provided a nozzle  44 . Initially the arm  30  is positioned so that the nozzle  44  is pointed straight down as indicated in FIG.  1 . This position of the nozzle is referred to as the initial or rest position. The gear  34  is arranged so that as the motor  36  rotates, the wheel  34  causes the arm  30  and nozzle  44  to turn about shaft  32  in a preselected direction. Thus, as motor  36  is activated, the nozzle  44  turns in a vertical plane Y—Y passing through the center of turret  16  as shown in FIG.  2 . 
     As previously mentioned, turret  16  is rotatable in either direction by any arbitrary angle about a vertical axis X—X by motor  20 . In this manner, nozzle  44  can be directed in any direction by rotating the housing  18  in a panning movement and then or simultaneously tilting the nozzle about shaft  32 . 
     Arm  30  is formed with a plurality of flat surfaces which may be arranged in different patterns as required. For example, as shown in  FIG. 1 , the arm  30  may be provided with two set of surfaces. One set of four surfaces  50 ,  52 ,  54 ,  56  is disposed at an angle of about 20° with respect to a vertical plane and arranged around nozzle  44 . Each of these surfaces  50 - 56  is provided with an infrared scan sensor  58 . Radially inwardly of surfaces  50 - 56  there is provided a second set of surfaces  60 ,  62 ,  64 ,  66  disposed at about 70° with respect to a vertical plane. Each of the surfaces  60 - 66  is provided with a seek sensor  68  angularly offset from the scan sensors  58  by 45°. Sensors  66  and  58  thus form a two-dimensional array around nozzle  44  as seen in FIG.  2 . 
     The scan and seek sensors  58 ,  68  are each arranged and constructed to monitor a solid cone directed along an axis normal to the respective surfaces  50 - 56 ,  60 - 66  through the room or area being monitored by device  10 . The sensors which may be either infrared photodetectors or pyroelectric ceramic sensors, generate electrical signals corresponding to the radiated energy sensed by the respective sensor in the solid cone. The scan and seek sensors are used to detect a fire in the room or area monitored by device  10  and to aim nozzle  44  through the motors  20  and  36  toward the fire. Details of the sensors  58 ,  68  and how they are interconnected is shown in  FIGS. 3 and 4 . As seen in  FIG. 3 , sensor  58 A consist of an infrared filter  70  and an phototransistor  72 . Light passing to phototransistor  72  is filtered by the infrared filter  70  to eliminate ambient light. Each of the other sensors  58 B,  58 C,  58 D,  68 A,  68 B,  68 C and  68 D are formed of similar filters and phototransistors which have been omitted herein for the sake of clarity. Sensors  58 A,  58 B,  58 C and  58 D cooperate to monitor the room or area of device  10  and when a fire is detected to pan the turret  16  generally toward said fire. For this purpose, inside housing  18  an electronic circuit  76  is provided consisting of a pan circuit  78  and a tilt circuit  80 . The pan circuit includes a clock generator  82  for generating clock signals at predetermined intervals. The clock signals are fed to a counter  84  which in response increments a count on a parallel bus  86 . Preferably, the counter is set to count from 1 to N where N is the number of scan sensors  58  (in this case four). The bus  86  feeds the count to a decoder  88  which in response activates the scan sensors  58 A,  58 B,  58 C and  58 D one at a time in sequence. The output of each sensor  58 A- 58 D is fed to a low pass filter  90 . Low pass filter  90  is used to filter the signals from the sensors to eliminate false signals generated by hot objects within the field of sensors. More particularly, it is known that the light intensity produced by fires is not constant but it flickers because of various physical parameters in a frequency range of about 5-30 Hz. Thus, low pass filter  90  is used to eliminate signals outside this range, such as for example a 60 Hz signal produced by a standard incandescent lamp. 
     The filtered signal from the filter  90  is fed to a driver  92  which is also connected to the decoder  88  so that the driver  92  can identify the sensor which has produced the signal received from the filter. Based on these received signals, driver  92  then drives the pan motor  20  either to the clockwise or counterclockwise as required to generally orient the housing  16  toward the fire. While the motor  20  is driven in response to a signal from one of the scan sensors, the counter is disabled through a line  94  also connected to the output of filter  90 . 
     The seek sensors  68  provide signals similar to the sensors of the scan sensors. If necessary, these signals may also be filtered as described above. 
     The pan motor  20  continues moving the housing  16  until one of the seek sensors disposed in plane Y—Y (i.e. sensor  68 B or  68 D) also senses the fire. For this purpose, the output of sensors  68 C and  68 D are fed to an OR gate  96 . When either of these sensors detects the fire, the signal output from sensor  96  disables the decoder  88 , which in turn stops motor  20  through driver  92 . At this point the seek sensors take over the operation of aiming the nozzle  44 . Because of the panning motion of motor  20 , the turret  16  has been rotated so that the fire is somewhere ahead of either sensor  68 B or  68 D. At this point, the nozzle  44  casts a shadow which occults the fire from one or two of the seek sensors  168 . The turret  16  and arm  30  are now moved around by the four seek sensors  68  until this shadow is eliminated and hence the nozzle is aimed at the fire. For this purpose the outputs of sensors  68 A and  68 C are fed to a differential amplifier  98  which in response generates an analog signal having an amplitude proportional to the difference between these two sensor outputs. The output of amplifier  98  V 1 out is fed to two comparators  100 ,  102 . Comparators  100 ,  102  determine if the amplifier output is outside a preselected range determined by two voltage signals HI REF and LO REF used as references signals by comparators  100  and  102  respectively. If the output V 1 out is above the preselected range, comparator  100  generates an output which is fed to driver  92  and used to drive motor  20  in one direction. If V 1 out is below said range, comparator  102  generates a signal which is fed to driver  92  to drive a motor  20  in the opposite direction. In this manner the pan motor  20  is used to align the nozzle quickly with one of the sensors  68 A,  68 C. 
     As can be seen from  FIG. 3 , a similar arrangement is used for the tilt circuit  80 . For this circuit, the outputs of sensors  68 B,  68 D are fed to a differential amplifier  104 . The output V 2 out of amplifier  104  is fed to two comparators  106 ,  108  for comparing this output to another preselected range. If V 2 out is above this range, comparator  106  activates a driver  110  which in response turns the tilt motor  36  in one direction. If the output V 2 out is below the preselected range, comparator  108  generates a signal for driver  110  for driving the tilt motor  36  in the opposite direction until the output of comparator  108  falls within the second preselected range. 
     In this manner the four seek sensors  68  cooperate to pan the housing  16  and tilt arm  30  until the nozzle is directed toward the fire. When the four seek sensors generate approximately equal outputs, i.e. none of them are occulted by the nozzle  44 , the output of comparators  100 - 108  are the same. These four outputs are fed to a relay  112  driver. Relay driver also receives an input from an OR gate  114  to indicate that at least one of the sensors  68  A-D is high, i.e. a fire has actually been detected. When the signals to driver  112  indicate that a fire has been detected and that the nozzle  44  has been properly aimed, the driver  112  activates a relay  116 . Relay  116  then opens a valve  118  ( FIG. 1 ) for pumping water or another fire extinguishing agent into nozzle  44  through a hose  120 . 
     The operation of the device is evident from the above-description. Suppose a fire breaks out in a zone F. The fire is first detected by scan sensor  58 B. In response to an output from this sensor, the pan circuit  78  of  FIG. 3  activates the pan motor  20  causing the turret  16  to turn counterclockwise until the fire comes into the view of seek sensor  68 B. At this point the scan sensors  58  are disabled and the four seek sensors  68  take over. Sensors  68 A,  68 C continue the panning until the plane Y—Y of the housing is passing through zone F. At the same time, the sensors  68 B,  68 D tilt the nozzle upward until it is pointed at the fire zone F. Once the aiming of the nozzle is completed, the relay  116  activates valve  118  and an agent is directed by the nozzle at the fire zone F. Relay  116  also generates a fire alarm signal on alarm line  122 . If the sensors no longer detect a fire, the relay  116  is disabled by driver  112  and valve  118  is closed. 
     Thereafter the device  10  is checked and serviced as required, the nozzle is re-oriented in the downward position, and the device is once again ready for operation. 
     In order to insure that the device operates properly, the scan sensors are arranged so that at least the field of vision of sensors  58 A,  58 B as well as sensors  58 C and  58 D overlap respectively to eliminate dead zones, i.e. zones in which a fire cannot be detected. 
     Of course the number of scan or seek sensors may be increase or decreased. Additionally, instead of the discrete circuitry shown in  FIG. 3 , a microprocessor based circuit may also be used, as shown in FIG.  4 . In this Figure, the eight sensors  58 A-D,  68 A-D are scanned sequentially by a microprocessor  200  through a multiplexer  202  and an analog-to-digital converter  204 . The sensor outputs may be filtered either by using analog filtering, or within the microprocessor, using a software implemented digital filter  206 . This filtering is performed to separate signals due to a fire from other infrared sources as discussed above. A logic unit  208  monitors the sensor outputs. The fields of the sensors are overlapped so that a fire zone F is indicated by the respective output of three sensors. These outputs are used by the logic unit to determine the location of the fire zone and to pan the turret  16  toward the fire zone through a driver  210  and simultaneously to tilt the arm through a driver  212 . After the nozzle has been aimed, the logic unit activates a driver  214  to energize relay  116 . A fire alarm indication  216  is separately energized by logic unit  208 . 
     Obviously numerous modifications may be made to this invention without departing from its scope as defined in the appended claims.