Abstract:
A flashing visual alarm system for buildings and institutions, having occupants including persons having impaired hearing abilities, is provided with on-site continuous monitoring devices and provisions for periodic operational tests of the strobe or incandescent lamp assembly in each room by an inspector, plus a centralized supervisor&#39;s station for the entire building complex where the operating status of each alarm lamp is continually displayed for the maintenance of a reliable and fully operational emergency warning system.

Description:
This is a continuation-in-part of application Ser. No. 430,937, filed Dec. 22, 1982 now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     This invention relates to alarm and warning systems, but more specifically, it relates to apparatus for assuring the reliability of visual fire alarm and warning systems for buildings and institutions frequented by persons having impaired hearing ability. 
     (2) Description of Related Art 
     Visual alarm systems have been used to alert persons having impaired hearing capabilities, the alarm being given by the flashing of a lamp installed within a room or area occupied by such persons. In large institutional structures it is especially important that equipment and methods be provided to test the alarm circuits and components to assure their reliability without causing undue concern by hearing impaired occupants who may interpret a test as an authentic emergency. 
     Zinsmeister (U.S. Pat. No. 3,810,170) discloses a visual signaling system for deaf persons using a high intensity strobe lamp. Means for testing and assuring the reliability of the apparatus are not provided. 
     Pichey (U.S. Pat. No. 4,017,825) teaches a highway intersection warning system for alerting motorists to the proximity of emergency vehicles and suggests but does not develop circuitry for a strobe lamp. The disclosure does not teach a means for testing and assuring the reliability of the warning system. 
     Finnegan (U.S. Pat. No. 4,222,047) teaches a failure detection apparatus for incandescent lamps using a low level test signal that does not illuminate the lamp in question. The apparatus is not applicable to the testing of high voltage discharge triggered lamps. 
     Johnson (U.S. Pat. No. 4,199,754) discloses a fire detection and emergency system, operable with an incandescent lamp fixture, with auxiliary lighting for fire and power failure conditions wherein circuitry is provided to bypass the on-off switch of the general illumination lamp. The apparatus does not operate with a flashing alarm lamp. 
     Mongoven (U.S. Pat. No. 4,449,073) discloses an airport runway approach lighting system including strobe lamps and discharge current monitoring means of fault detection. 
     Cady (U.S. Pat. No. 3,189,788) discloses a battery operated circuit for the illumination of indicating lamps upon failure of AC line power. 
     It is common practice to test fire alarm circuits by sending a current through the circuit and monitor the current flow to activate warning devices if a deficiency in current flow appears. But strobe lamps are especially useful for alerting hearing impaired persons to emergencies, however, the reliability of a strobe lamp cannot be tested or monitored by means of a low lever continuous current. In institutional buildings it is not practical to frequently flash test the full complement of all the strobe lamps at once, because, being understood to represent a fire alarm, such testing could frighten the hearing impaired occupants or cause them to take unwanted action. 
     SUMMARY OF THE INVENTION 
     This invention provides means to assure reliability of a visual alarm system for institutional buildings and residences having hearing impaired occupants. Two procedures for assuring reliability where a number of units are in use are to monitor the current flowing into the wiring system up to the strobe lamp and to occasionally have an attending inspector operate, on-site, each strobe lamp. On-site and remote indications of system reliability are provided. 
     It is the principal object of this invention to provide improved visual alarm apparatus. 
     It is another object of this invention to provide more dependable visual alarm apparatus by continuous supervisory monitoring, by on-site displays and by on-site operational tests of the actual alarm lamp. Other objects, features and advantages will become apparent from the description in connection with the accompanying drawings of the presently preferred embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described with reference to accompanying drawings, in which: 
     FIG. 1 is a block diagram of the apparatus for supervisory monitoring and for reliability assurance of a visual alarm system. 
     FIG. 2 is a first circuit schematic of an on-site reliability assurance system for a visual alarm system. 
     FIG. 3 is a second circuit schematic of an on-site reliability assurance system. 
     FIG. 4 is a third circuit schematic of an on-site reliability assurance system. 
     FIG. 5 is a fourth circuit schematic of an on-site reliability assurance system. 
     FIG. 6 is a first circuit schematic for a monitoring apparatus for remote indication of system status and reliability. 
     FIG. 7 is a second circuit schematic for a monitoring apparatus for remote indication of system status and reliability. 
     FIG. 8 is the conventional circuit for the excitation of a strobe lamp. 
     FIG. 9 is an excitation circuit of a flashing incandescent alarm lamp for use in a reliability assurance system. 
     FIG. 10 is an illustrative schematic of an integrated status monitor and reliability assurance system according to the block diagram of FIG. 1. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to FIG. 1 there is illustrated in block diagram form a status monitor and reliability assurance circuit for a visual alarm system according to the present invention. A visual alarm lamp 100 is operated in a flashing mode during emergencies by an excitation circuit 200 in response to control, by an alarm source 500, of an interface relay 300 which applies line power from an alternating current(AC) input supply 400. On-site monitoring of the integrity of the system wiring and the presence of AC line power up to the lamp excitation circuit 200 is by means of a monitor current supply network 600 and a local visual display 700 both of which operate continually while the interface relay 300 is normally deenergized. Periodic operating tests are performed onsite by an attending inspector, going from room-to-room, who informs the occupants of the area of the nature of the test should any occupants be present. Test circuit 800 is used to apply AC line voltage directly to the lamp excitation circuit 200 so as to flash the alarm lamp 100. The operating status of each alarm circuit in a multiple room(alarm) installation is continually monitored at a supervisor&#39;s central display 900. 
     FIGS. 2-5 illustrate preferred embodiments of the local on-site reliability assurance circuits wherein like components have the same numerical character designations. Terminals 1 and 2 are connected to the AC power line of which 2 is the neutral or grounded wire. The interface relay 3 is activated by the alarm control source 500(not shown in detail), which may be a fire alarm controller, smoke detector, or other like operating emergency controller. The local visual display(700 of FIG. 1) is a light emitting diode 4 in a circuit with a current limiting resistor 5, a rectifying diode 6, and a voltage protecting zener diode 7. 
     FIGS. 2-5 show a lamp assembly indicating a strobe lamp 40 with conventional excitation circuits 8, having input terminals 41 and 42 corresponding to AC input power line 1 and neutral 2 wiring respectively. FIG. 8 is a detailed electrical schematic of the strobe lamp assembly including the alarm lamp and its excitation circuit. FIG. 8 shows a voltage doubler circuit of rectifiers 32 and 33 and capacitors 34 and 35. The doubler provides direct current to the trigger capacitor 36 through a charging resistor 37. When the voltage across the trigger capacitor 36 rises high enough, a discharge occurs across unit 39 which may be a neon lamp or equivalent solid state device, or an air(spark) gap. The autotransformer 38 reacts to the discharge at unit 39, causing a high voltage pulse into the strobe lamp 40 which in turn releases the stored energies(charges) of capacitors 34 and 35 through the lamp to fire the strobe 40 giving a flash of high intensity illumination. With continued application of AC power the process repeats. If for any reason the AC voltage at lamp terminals 41 and 42 is inadequate the capaictor 36 will fail to discharge through the air gap 39 and the strobe will not fire. Reliability requires that adequate voltages be delivered through the wiring and circuits to the strobe lamp 40. 
     In some situations, as for example in rooms of an institution where the occupants are always awake and alert, it may be permissible to use an incandescent lamp 43 driven by a convential flasher unit 46 and full wave zener diodes 44 and 45 constituting an excitation circuit connected to terminals 41 and 42. The ratings of the zenners 44 and 45 are selected so that the lamp 43 cannot operate below a voltage threshold at terminals 41 and 42. Below this threshold the status circuits of FIGS. 6 and 7 and the reliability on-site monitors of FIGS. 2-5 are operable. 
     Returning to FIGS. 2-5, means are provided whereby a monitoring current is obtained by circuits bypassing the normally open contacts 52 and 53 of the interface relay 3. In FIGS. 2 and 4 a small current is obtained by the series network of a limiting resistor 11 and a rectifying diode 12 arranged in shunt across the normally open contacts 52 and 53. In FIG. 3 the monitoring current is obtained by use of a step-down voltage transformer 15. The transformer has a primary winding connected across the AC input terminals 1 and 2 and a secondary winding connected from the neutral bus 2-42 through a rectifying diode 12 and the normally closed contacts 52 and 54 of the interface relay 3. In FIG. 5 the monitoring current is obtained by a direct connection to the AC input line terminal 1, the value of the limiting resistor 5 being adjusted for the full line voltage. 
     In FIGS. 2-5 a means for an attending inspector, going from room-to-room in the building, to excite and perform a full on-side test of each alarm lamp, be it a strobe 40 or an incandescent lamp 43, requires a method and means of bypassing the interface relay 3 with full AC line voltage. As shown in FIGS. 2-4 each lamp fixture may have at its surface an accessible terminal 9 for making electrical contact thereto. The inspector is provided with a portable polarized(conductive) extension cord and probe with mating terminal 10(for reaching fixtures at ceiling heights). The inspector inserts the cord 10 in a convenient AC room outlet an applies AC line voltage effectively from terminal 1 to terminal 41 of the excitation circuit. In lieu of the inspector&#39;s electrical probe 10, a conductor may be hard wire in the fixture from terminal 1, bypassing the interface relay contacts 52 and 53 to a protected inspector&#39;s switch 47, momentarily operable by a key or a portable magnetic probe 63 to apply the AC line voltage to the excitation terminal 41(see FIG. 5). The protected switch is desired to preclude unauthorized operation of the alarm lamp circuits. In FIG. 5 a high resistance 62 shunting terminals 41 and 42 provides a path for current flow to enable the operation of the status sensing circuits of FIGS. 6 and 7. 
     In the circuit of FIG. 4, a monitor relay 13 has its coil 14 connected from the neutral bus 2-42 to the test terminal 9. Normally closed contacts 59 and 61 permit the flow of monitor current from the bypass network resistor 11 and diode 12 through the monitor display network and its light emitting diode(elements 4,5,6 and 7). To test fire the alarm lamp the inspector applies line voltage at terminal 9, activating the monitor relay 13 so as to apply line voltage effectively from terminal 1 through normally open contacts 59 and 60 to the excitation terminal 41. The operation of the relay 13 disconnects the monitor visual display network, elements 4-7, from the controlled line bus 52-41 thereby avoiding voltage transients to the elements due to inspector&#39;s testing. 
     In a multiple room building or institution status indication at a central or remote supervisor&#39;s station is sueful for coordination of repairs of malfunctions or prompt actions in response to an actual emergency such as a fire. FIGS. 6 and 7 illustrate circuits for supervisory monitoring. In FIG. 6 the status monitor is a series network of a light emitting diode 20, a resistor 17, a zener diode 18 and a rectifying diode 19. In a preferred embodiment the network bridges the normally open contacts 52 and 53 of the interface relay 3, with at least the light emitting diode 20 located remotely at the supervisor&#39;s station display. Failure of the diode to emit light will indicate one of three conditions. A momentary failure to emit light indicates that the maintenance inspector has just tested, on-site, the operation of the alarm lamp in the specific room. A prolonged failure to emit light indicates either an open circuit with absence of AC line power or a closure of the interface relay 3 in response to a fire condition, both being events that require the immediate attention and action of the supervisor. 
     The function of the status sensor is expanded in the circuits shown in FIG. 7 to indicate short circuits in the alarm fixture and to provide audible warnings at the remote central station of the supervisor. Two status sensing networks are provided both bridging the normally open contacts 52 and 53 of the interface relay 3. In the first status sensing network, a diode 19, resistance 17, and zener 18 diode are arranged in series with each other and with a light emitting diode that is constructed as a subelement of a component called an &#34;opto&#34; 21. The light emitting diode 48 subelement is optically coupled with a photo transistor subelement 49. The photo transistor 49 controls power from a battery 31, or equivalent power supply, and activates the auxiliary relay 22. Under normal conditions the current through the opto 21 will keep the relay 22 energized thereby opening the contact 55 and 56 preventing the bell, lamp or other alarm 29 located at the supervisor&#39;s central station from operating. Again as described for the status network of FIG. 6, momentary failure of the opto 21 to conduct thereby ringing the bell or other alarm 29 at the supervisor&#39;s station indicates an on-site inspector&#39;s test of the alarm lamp operation. Prolonged failure and bell ringing indicates either a fire condition or open circuit failure of the fixture or system, both being conditions requiring urgent action. Similarily, the second status sensing network has elements including a zener diode 23, a rectifying diode 24, a resistor 25 and an opto 26 containing light emitting diode 50 and optically coupled photo transistor 51 subelements for control of a second auxiliary relay 27 having normally open contacts 57 and 58 for connection of battery 31 power to a supervisor&#39;s bell or other alarm device 28. In the event of a short circuit or excessive leakage within the alarm lamp 40 or 43 or the lamp excitation circuits shown in FIGS. 8 and 9 the voltage across the series network of elements 23-26 will rise above the established zener 23 threshold causing the opto 26 to conduct and energize relay 27 so as to activate the supervisor&#39;s alarm 28. To maintain reliability of the alarm system the supervisor is required to respond with corrective action on indication of a shorted circuit in the local alarm system. Each supervisor&#39;s alarm device 28 and 29 may provide visual as well as audio indications for aiding in rapid determination of the source of the emergency or malfunction. 
     The supervisory status indicating networks of FIGS. 6 and 7 are compatible additions to any one of the on-site reliability monitors, FIGS. 2 through 5. The wiring connections are made at terminals 1 and 41 or their equivalents such as interface relay contacts 52 and 53. For example, FIG. 10 illustrates a fully integrated status monitor and reliability assurance apparatus for visual alarm system. In FIG. 10 the supervisory status monitor of FIG. 7 has been merged with the on-site reliability monitor of FIG. 2. Without further illustrations it is readily apparent that the preferred embodiments include combinations of the elements and functions of FIGS. 2 through 9. 
     From the foregoing disclosure of the improvements of this invention it is apparent that operational status can be indicated for supervisory control, and reliability of the visual alarm apparatus can be assured by responding to the indications of routine on-site monitoring and testing. Variations and modifications of the herein described embodiments are within the scope of the present invention. Accordingly the foregoing description should be taken as illustrative and not in a limiting sense.