HOEGSTROEM PER A (SE)
HOEGSTROEM PER A
| GB1420935A | 1976-01-14 | |||
| US4199754A | 1980-04-22 | |||
| CH517979A | 1972-01-15 |
| 1. | A system for indicating an emergency exit in case of fire in a building, comprising at least one flash light located near floor level and having an associated drive unit, including a trigger circuit, and accumulator batteries and means for sensing disappearance of the supply voltage to the drive unit and actuating the trigger circuit at such disappearance. |
| 2. | A system according to claim 1, in which a flash light is located at each side of an emergency exit nearby the floor. |
| 3. | A system according to claim 1 or 2, in which the flash lights are located on a level of 70 cm at most over the floor. |
| 4. | A system according to any of the preceding claims, in which said means for sensing disappearance of supply voltage consist of a voltage level sensing circuit with such a time constant that the circuit does not react on normal fast mains fluctuations, said circuit controlling switch means for connecting the accumulator batteries to the drive circuit of the flash lights.. |
| 5. | A system according to any Gf the preceding claims, In which the drive unit Is fed in parallel with lamps of an emergency sign, that also includes emergency lights arranged for being connected in parallel with the accumulator batteries in case of disappearance of voltage. |
| 6. | A system according to any of the preceding claims, In which the mains supply leads include fire detector controlled switches by means of which the mains voltage is interrupted or pulsated in case of alarm. BAD ORIGINAL ( /, WI. |
The present invention relates co a sys em for guidance to the emergency exit in a building.
The object of the invention is to provide a system of the kind indicated above, that provides reliable guidance also in very heavily smoke filled spaces and that cannot be put out of operation by any type of cable fault, voltage interruption or the like.
The system according to the invention includes at least one flashlight located on a low level above floor. A drive unit associated with the flash light includes a trigger circuit and accumulator batteries. Means for detecting disappearance of he supply voltage are also included. Suitably the level of the flash lights above floor is
70 cm at most. Preferably two flash lights are located each on its side of an emergency door exit quite close to the floor. These flash lights ;ιreferably have a drive unic in common.
The invention has the folLowing advantages; In case of fire always the upper portion of a room is first filled with smoke, this fact -forming the basis of the advice that one shall try to leave a room, that is being filled with smoke, crawling. This, however, also implies that conventional emergency exit indication devices which are located above the emergency exit become invisible relatively fast due to the thickening smoke so that accordingly the emergency exit becomes difficult to find. If, in accordance with the invention, the flash lights are located nearby the floor on each side of the emergency exit this problem is eliminated. Furthermore, the system according to the invention cannot be put out of., operation in case of intermittent or complete disappearance of the supply voltage since the drive unit includes a means for sensing such disappearance and brings the trigger circuit to automatically start the flash light. The same effect is attained at short circuiting of the voltage supply. Alarm signals from fire and saoke detectors can be fed to the drive unit superposed on the supply leads, or on a separate signal wire.
The invention will now be described more closely below with reference to the attached drawing that illustrates an embodiment of a system according to the invention as combined with e
, On the drawings Figure 1 illustrates an emergency door opening to which the system is applied, Figure 2 is a schematic circuit diagram of a system according to the invention, and Figure 3 is a schematic diagram of a trigger circuit included in the system.
Mains fed lamps 1 and battery fed emergency lights 2 are included in an emergency sign 3 of conventional design located above a door opening 4. A switch 6 in the mains feed line is controlled by fire and smoke detectors for interrupting or pulsing the voltage supply in case of fire. In the latter case a twinkling light is obtained from the lamps 1 for indicating danger. Via a transformer 8 and AC - DC converter 10 said interruption or pulsing is sensed at the point 12, on the one hand via a lead 14 by a trigger circuit 16 for flash lights 18, and on the other hand by a relay 20, that at voltage disappearance connects the emergency lights 2 in parallel with accumulator batteries 22. The flash lights 18 are located near floor level at each side of the door opening 4, preferably at a level of 70 cm at most over the floor.
The trigger circuit 16 can be of a conventional design easily realized by the man of the art and schematically shown in Figure 2. Thus, it can include a voltage level sensing and time dependent IC circuit 24. The time constant is determined in known manner by means of a capacitor and resistor network so that the IC circuit 24 does not reacc to normal fast mains fluctuations but rather on the above mentioned pulsations. The output from the level sensing circuit 24 is connected to the base of a transistor 26, the collector-emitter path of which is connected in series with the accumulator batteries 22 over the flash lights 18 with the associated drive circuit. The transistor 26 is thus brought to a conducting state via Che level sensing circuit 24 in case of interruption or pulsation of the mains voltage so that the drive circuit of the flash lights is actuated.
Below two examples of dimensioning values of the circuit of Fig. 2 are given.
24 V AC supply 24 V DC supply
R 1 = 380.SY 2 = 27_fl_ L = 780∑V R 2 = 47-T*. z = 7,5 V,1W z « 7,5 V
R 3 = 100 R = 47 other components as In the AC case
R 5 = 15Λ C L - C 2 - 10/ΛF
D 1 = D 2 = 1A, 100 V
In both cases the batteries are 4 NiCd cells of 4,8 V
The flash lights can be conventional photo flashes of the discharge tube type with a suitable frequency of discharge. At such photo flashes ignition is obtained by a periodically built up electrostatic field via charge and discharge of a capacitor battery.
BAD ORIGINAL