DE2728309B2 - Fire alarm device - Google Patents

Description

The invention relates to a fire alarm device as specified in the preamble of claim 1 Art.

Such a fire alarm device is known (DE-AS 20 51 649). Here is after the generation of the alarm signal, the integration circuit designed as a digital counter as a function of the sequence a predetermined measuring time reset to zero, whereupon the evaluation circuit in the center again is ready for use. To restore the operational

ϊο the readiness of the entire reporting system is in the Practice also required the self-holding of the electronic detector, which was initially addressed had to be canceled by interrupting the line voltage again after the deletion has started. only this way

Vi can namely the renewed response of another electronic detector or the actuation of a manually operated detector again be evaluated as an alarm signal, for example if a fire intensifies again after an attempt to extinguish it. To

f> o the abolition of the self-retention of the original addressed electronic detector, it is disadvantageously no longer possible to determine which Detector originally caused the alarm signal to be emitted by responding, i.e. closed the seat of the fire

locate h ^r '. Furthermore, with the known fire alarm device there is the risk that an alarm signal will be incorrectly generated again after an alarm signal has been generated. This is because a once addressed

chener detector, especially when designed as a Ionization smoke detector that has a tendency, after its self-holding has been lifted, by interrupting the To address line voltage again, even if the value of a Fire consequences, for example the concentration of smoke gases in the ambient air, among the has reduced the threshold value originally required to respond because there is no longer a fire.

From DE-PS 22 30 934 it is known to avoid the aforementioned difficulties by that the addressed detector is made ineffective after generating the alarm signal that a switch-off signal to him via a separate signal channel, generally an additional conductor of the line is supplied, which has the effect that the detector is addressed and thus remains identifiable, but that the line current increase originally caused by it is reversed, so that the response another detector leads to an alarm signal again. The separate signal channel here requires one increased circuit complexity.

The invention is based on the object of providing a fire alarm device of the type mentioned in the introduction in terms of circuitry uncomplicated to develop so that after the response of a detector this remains identifiable even after the alarm signal has been generated, but initially no longer to generate a Alarm signal can contribute, and that after generating the alarm signal when other detectors respond an alarm signal can be generated again.

The object is achieved according to the invention in a fire alarm device of the type mentioned solved by the measures specified in the characterizing part of claim I.

In the fire alarm device according to the invention, the electronic alarm device that initially responded remains in the addressed state after the alarm signal has been generated, since the interruptions in the line voltage are then not continued. By switching the threshold value circuit to a higher threshold value, it is achieved that a further alarm signal can only be generated when a further electronic detector responds. In this further msignal Ala ^r a possible erroneous response of the detector first mentioned has no effect, since this detector is maintained until the generation of the further alarm signal in any case in the addressed state. It is therefore not necessary to switch off the first addressed detector via a separate signal channel or in any other way.

The invention is explained in more detail below with reference to the drawings, in which exemplary embodiments are shown. It shows

1 shows a first embodiment of a fire alarm device according to the invention;

FIG. 2 e: in a time diagram to explain the mode of operation of the fire alarm device according to FIG F i g. I; bO

F i g. 3 shows a second exemplary embodiment of a fire alarm device according to the invention;

4 shows a time diagram to explain the mode of operation of the fire alarm device according to FIG Fig. 3;

5 shows a third exemplary embodiment of a fire alarm device according to the invention;

6 in a schematic representation a possible modification of the fire alarm device according to FIG. 1, 3 or 5.

The in F i g. Fire alarm device shown 1 umfaüi a central station Z and a to the output terminals 10, 12 connected line L to the two wires 14, 16 or line L parallel to one another electronic fire detector De are connected, and the line L is facing away from the central station Z end of one Line terminating resistor R completed in order to be able to carry out monitoring for short circuits and interruptions in the control center Z in a manner not shown.

In the central office Z, a battenegepufferte, mains-powered DC voltage source, which is shown in the illustration for simplicity by a battery B, the line L fed One pole of the battery B is via a closed in the non-actuated state electronic switch 18 and a current measurement member 20 connected to the terminal 10, the other pole of the battery B is connected directly to the terminal 12. Between the connections 10, 12 there is the Lii., Envoltage u, which, when the switch 18 is closed , is the same as the voltage of the battery B apart from a negligibly small voltage drop in the measuring element 20. The output signal of the measuring element 20 is directly proportional to the line current flowing through the connection 10.

The output signal of the measuring element 20 is fed to a threshold value circuit 22, the two threshold value switches 24, 26 includes. Between the measuring element 20 and the threshold switch 24 there is an inoperative State of closed electronic switch 28 switched, while between measuring element 20 unc Schu eilwertschalter 26 an electronic switch 30 ', which is open in the non-actuated state, is located. The switches 28,) are 0 can be operated jointly and therefore jointly form a changeover switch, each of which only has one of the threshold value switches 24, 26 connects to the output of the measuring element 20.

The threshold value switch 24 is followed by a delay element 32 which, when an output signal from the threshold holder 24 appears, disrupts an output signal during a measurement time determined by its delay time; e ^r stuff. As a result, a pulse generator 34 can be actuated during the measurement, which generates square-wave pulses. The follow-up time of the square-wave pulses is short compared to the measurement time. and the duration of the impulses is short compared to their subsequent time. With the pulses from the pulse generator 34, the switch 18 is actuated via an OR gate 36.

In addition to one input of the OR element 36, an input of an AND element 38 whose other input is connected directly to the output of the threshold switch 24 is also connected to the output of the pulse generator 34. The output signals of the AND element 38 are applied to an integrator 40. Its integration result is applied to a further threshold switch 42, which is switched after it. This is displayed by a symbolically indicated display device 48. The alarm signal from the memory 46 is also fed to a dynamic set input of a further saliva 50 which, when set, gives a clear signal L ib. The memory 50 is closed by closing a

Switch 52 is reset by doing this generated signal via an ODKR element 54 his Reset input is supplied. The memory 46 emitting the alarm signal is by closing a Switch 56 reset. With the signal that can be generated by switch 5h, all becomes the reset input of the memory 56 is also an input of the ODKR element 36 and thus the switch 18 as well as a Kingang of the ODKR element 54 and thus the l.öscheingang des Memory 50 acted upon. Dir Aiisgamrssipnalc des Activate the power switch 2h ubi'i cm ί > DI K Chcd 58 on the one hand via the ODI-U element -44 4h memory se'ze entrance and .tndrrcrscUs ιίιιιίι W our dynamic .set input of the Spcii is called 50

In addition to the electronic detectors Pc / ii these can be connected to wires 14, lh de; Line /. mim hand operated report connected scm I.in

shown. The I .miensiromerhohuiig around an inland detector Pm when it is activated is greater, whereas the I .mienstnohuiig generated around a cleverly mixed detector / V when it is activated; In the Nusluh example, the line current increase that can be generated by an inland detector Pm (.las triple '.' the line current increase in an electronic detector Pc . a separate threshold value switch W) connected to the signaling element 20 is provided. Whose ggt. The output signal generated is a further Kingani: the ODLR member 58 leads trains, so that it acts on a Sct / input of the memory 46, 50.

The mode of operation of the fire alarm device according to! ■ 'ι g. 1 is the laudatory with additional consideration of the I ι g. 2 explains, νιο among each other lic l.line tension ti. the l.inistrom; and the l.nscnsignal /. depending on the / eil / are represented in different assumed etrics.

When the message is in the idle state, the switch 18 is closed, in the.! the line I. is supplied with the> ■ i.ipiens voltage w as direct voltage. Thereby a lower quiescent current flows than l.iniens-.rom; essentially via the line termination resistance K. Now an electronic detector Dc .in speaks. so the line current increases; by the amount of di \ the "- output of Meßglieds 20 increases proportional Thus, the threshold value Y has been exceeded ₂₄ the .Schwellwertschalters 24, and this generates a ■ \ useangssignal Then - even if the Ausgangssienal of Schwrüwertschalters 24 in the following again -.. . · ■■ invisible - also generates the timer 32 during a fixed measurement time an output signal, and during this measuring time the pulse generator 24 generates pulses by these pulses, the switch is briefly opened during the measurement time at periodic intervals 18. this causes the line voltage u.. periodically interrupted; its value drops briefly to 0. In FIG. 2, as a simplified example, it is shown that four interruptions take place during the measuring time T. M

By interrupting the line voltage u , the self-holding of the addressed detector De is canceled. However, if the first response of the detector De is not based solely on a cause of the fault, but on the existence of a consequential fire effect, this consequential fire effect will continue to exist even after the first response, so that the detector De closes each time the line voltage u is switched on again of the Sehalters 18 responds again. This results in the in Ii g. 2 course of the lines current / shown during the measurement time T; he sways! periodically between a value above the threshold value x _M and zero. Whenever the pulse generator 34 does not generate an output pulse, the first line voltage // thus has its series value and the first line current / threshold value \ n , so that the output signal of the threshold value switch ¹ ! 24 is present, generates d: vI 'Ν I) <üieii (8 an output signal impulse of the Ins zui nai ¹ IiStIi ili'enden interruption of the I.iriiensp.inni.iiL'. 'Diifi h eiru η impulse of the impulse generalor Ϊ4 nnsiehi The Visr The signal pulses of the AND element W are integrated into the integrator 40! During the melting period / nai.h, at least the majority of all parts of the first line break . , .....,,;.,. ... ι. ... ■; ....,; ....... (....!; ,,!:., i _vs s;, _ ι ,,,.,. π,., ,,. ..,, ._ ■■ * VI hegendei l.inienstrom / leslgc.telll. so iibei schreii · ¹ das Iniei'i, liumsei'gebrus and thus the Hetr.ii: '■ • \ usg, ingssp; iiHiung of the integrator 40 deri thresholds wr: des schw eil w <· rl se Maliers 42, whereby the pen her 4h ge ·.''wii.i. whose output sign, which has now been obtained, is displayed in the display precedence 48. .ιικ h de ¹ memory ·. H "· 50 iTc is set and thus the l.osi hsiun.d 'is given if \ l

Since the Marmsignal \ om memory 46, cmc (opening of switch 28 and closing of switch JO causes the S (i.e., wellweit sch.lining 22) to be switched with regard to its threshold value in such a way that the last of the

,! en amount dl

Threshold value \., Of the threshold value switch 26 instead of the threshold value \, becomes effective. Here, the electronic detectors / V remains older first anges | ircn hay had, because of his ^ elbsthaltung and because of this, no I li.ili nterbrechungcn the I .intenspannung ii done more in angcspnichencn state, dall the line current / an already above the Threshold value V ₁ retains WrI.

Automatically at the beginning of the process of failure or arbitrarily when it is no longer necessary or no longer necessary. the memory 50 is reset to the idle state by actuating the switch 52 m. With that it disappears! ο sch sign a I / .. The alarm signal generated by the memory 46 that has been set, however, is maintained and reminds that the fire site must be localized by looking for the originally addressed detector Dc, which is still in the addressed state.

Another electronic detector Dc will now respond. for example, because a deletion attempt was unsuccessful, there is an overall line current increase of 2di compared to the quiescent current. The line current / the threshold value X2t of the threshold value switch 26 thus exceeds the output signal of the threshold value switch 26 again sets the memory 50, and the clear signal L is generated again until the memory 50 is reset again by actuating the switch 52. Thereafter, the further addressed detector De remains in self-holding and can also be localized.

Once the fire has been extinguished and the detectors De concerned have been identified and, if necessary, replaced, the switch 18 is briefly opened by actuating switch 56, the line voltage u is interrupted and all electronic detectors De are reset to retirement.

At the same time, the memory 46 and possibly the memory 50 deleted.

If the manual call point Dm is actuated, this results in a line current increase 3di of three times the amount of that line current increase di that is generated when a single electronic detector De is triggered. As a result, _{the threshold value Ar 60 of} the threshold value switch 60 is exceeded in any case, whereby the memories 46, 50 are set and the alarm signal and the extinguishing signal L are generated regardless of whether an electronic detector De had already responded or not.

The embodiment of the fire alarm device according to FIG. 3 agrees with that of FIG. I partially match; the same parts are with the same ϊί Reference numerals denoted. Notwithstanding FIG. However, 1 is the output signal of the threshold switch 26 does not work properly with that of the threshold switch «; 60. but with that of the Srhwpllwprtschalters 24 combined via an OR gate 62.

As can be seen from FIG. 4, after a first electronic detector De has responded, the mode of operation of the reporting device according to FIG. 3 with that according to FIG. 1 match, so that towards the end of the measuring time Γ the periodic interruption of the line 2 => voltage u and the line current / is set, the extinguishing signal L is generated, the originally addressed electronic detector De remains in self-holding and the threshold value circuit 22 with regard to its threshold value is switched.

If a further electronic detector De responds when the threshold value circuit 22 has been switched over, the line current of / above the threshold value Xx of the threshold value switch 26 increases again, as a result of which this and thus r> the threshold value circuit 22 emit an output signal. As a result, in the same way as shown on the basis of FIG. 1 has been described for the exceeding of the threshold value X2t of the threshold value switch 24, the line voltage u and thus the line current; periodically interrupted. Only if after each interruption both the electronic detector De addressed first and the electronic detector De addressed later respond again, the integration result of the integrator 40 will again exceed the threshold value of the threshold value switch 42, approximately after the measuring time has elapsed again, so that the alarm signal again and by means of of the memory 50, which is acted upon directly by the OR gate 44 here. the erase signal L can be generated. The fact that the clear signal L can only be generated when the threshold circuit 22 is switched to the higher threshold value X2t if two electronic detectors De respond again after each interruption of the line voltage u , the security against false alarms is increased in this operating state

If in Fig. 3, the manual call point Dm is activated in the same way as shown in FIG. 1 and 2, an alarm signal and a clear signal L are generated immediately

The further exemplary embodiment of a fire alarm device according to FIG. 5 agrees with that according to FIG. 3, as far as the same parts are denoted by the same reference numerals. Notwithstanding FIG. 3, however, the parts 32, 34 and 38 are omitted, the integrator 40 is connected directly to the output of the threshold value circuit 22, and for the intermittent interruption of the line voltage u by means of the switch 18, a timing element 64 is provided between the output of the threshold value circuit 22 and an input of the OR gate 36 is connected. The timing element 64 generates an output pulse after a delay time which corresponds to the pulse spacing of the square-wave pulses of the pulse generator 34 in FIGS. 1 and 3, during a time which is shorter than this delay time. This results in the same mode of operation as in FIG. 4, provided that after each interruption the first addressed detector Dc or after switching the threshold value circuit 22 to the higher threshold value, both addressed detectors De respond again. In contrast to FIGS. 3 and 4, the line voltage u and the line current / are interrupted not necessarily periodically during a predetermined measuring time T, but rather the interruptions spt7Pn ans. falk narh pinpr prnpulpn Fintrhal-

processing the ^Lin: Enspannung u by closing the switch 18 takes place no new line current increase above the threshold value A ^ or Xn addition.

The integrator 40 in FIG. 5 is designed in such a way that it generates a disappearing signal, ie its output signal, based on the respective integration result, assumes the value zero again after some time if input pulses are not fed to it again. As is known, this effect can be achieved, for example, by connecting an ohmic bleeder resistor in parallel to the integration capacitor of the integrator 40. The integration constant of the integrator 40 is chosen so that the threshold value of the threshold switch 42 is exceeded and a clear signal L is generated if, after an electronic detector De has responded for the first time and the line voltage u and the line current are interrupted, the electronic detector responds again De occurs and if this game continues several times in a row. In the reporting device, a measuring time T (FIG. 2, 4) is not permanently provided, but a clear signal L is only generated if an approximately periodic interruption of the line voltage u has occurred in a time period approximately corresponding to this measuring time.

The embodiment of a fire alarm device shown in FIG. 6 largely corresponds to FIG. 5; the in F i g. 5 to the right of the threshold value circuit 22 are symbolized by a block 66. Notwithstanding FIG. 5, however, the threshold value circuit 22 is designed to be switchable several times with regard to its threshold value. For example, instead of switches 28, 30, it can comprise a multiple switch and instead of only two threshold switches 24, 26 a number of threshold switches corresponding to the number of different thresholds, the output signals of which via an OR element having a corresponding number of inputs similar to OR Link 62 in FIG. 5 can be summarized. The switching of the threshold value circuit 22 is controlled by a counter 68; each time an alarm or delete signal occurs, the counter 68 is incremented, whereupon the threshold value circuit 22 is switched to the next higher threshold value. This makes it possible to detect the response of a fourth, fifth, etc. electronic detector De and to evaluate it to generate an alarm or extinguishing signal.

th, while all of the aforementioned electronic Detector De remain addressed.

Also in Fig. 6, an alarm or cancellation signal can be generated by means of a manual indicator Dm via the threshold value switch 60, which signal is output via an OR element 70. The line current increase that can be generated by the manual call point Dm must be higher than the highest adjustable threshold value of the threshold value circuit 22, and the threshold value Xm of the threshold value switch 60 must have a correspondingly high value in order to be able to benefit from the values generated by the block 60

ίο

Signals to be distinguishable.

Further modifications of the fire alarm systems shown are of course possible. So can, similar to that in Fig. 6 to control the Threshold circuit 22 is shown, the cases of occurrence of the alarm signal are counted and depending on Different measures can be taken depending on the ordinal number of the generated alarm signal. For example can only generate a pre-alarm in the event of one occurrence, a full alarm in the event of a second occurrence, etc. will.

For this purpose 3 sheets of drawings

Claims (8)

Patent claims: 1. Fire alarm device with a two-wire line connected to a control center, with electronic detectors connected in parallel to the wires of the line, which in the event of a report go into self-holding that can be canceled by interrupting the line voltage and cause an increase in line current by reducing their impedance, and with an in The evaluation circuit provided in the control center, which has a current measuring element connected to a wire of the line, a threshold value circuit connected downstream of this, which emits an output signal when the line current increase generated by an electronic detector, a switch connected to a wire of the line, which, depending on the presence of the The output signal of the threshold value circuit briefly interrupts the line current, as well as an integration circuit acted upon by the output signals of the threshold value circuit, which generates an alarm signal when a predetermined integration result is reached characterized in that the threshold value circuit (22) is designed to be switchable to a higher threshold value (x ₂ b) , so that in the switched state it produces an output signal only when a line current increase (di) greater than that generated by an electronic detector (De) occurs. s'romerhöhung (2di) indicates that the switchover of the threshold value circuit (22) to the higher threshold value (\ _Λ ) by the alarm signal (from memory 46) is successful, r.nd that a further alarm signal can be generated if you. in the switched state threshold value circuit (22) supplies an output signal. 2. Fire alarm device according to claim I, characterized in that the threshold value circuit (22) has a first threshold value switch (24) connected to the output of the measuring element (20) via a switching path (28) of a changeover switch (28, 30) which is conductive in the non-actuated state ) and one / wide threshold switch (26) connected to the output of the measuring element (20) via a non-conductive switching path (30) of the changeover switch (28, 30) with the threshold value (x ») of the first threshold value switch« ( 24) has a higher threshold value (x ₂ b) and that the uniswitch (28, 30) is actuated by the alarm signal (from memory 46). 3. Fire alarm device according to claim I or 2, characterized in that the switch (18) unc the integration circuit (40) only then in Depending on the output signals of the threshold value circuit (22) are controllable if this ir their non-switched state is (Fig. I). 4. Fire alarm device according to claim 2 and 3, characterized in that the switch (18) and the integration circuit (40) of the first Threshold switch (24) can be controlled. 5. Fire alarm device »according to claim I or 2, characterized in that the switch (18) and the integration circuit (40) in all switching states that of the threshold value circuit (22) are controlled by its output signals (Fig. 3, 5). 6. Fire alarm device according to claim 2 and 5, characterized in that clip threshold value scarf device (22) has an OR gate (62) on the output side, the inputs of which are derived from the output signals the threshold value switch (24, 26) are acted upon. 7. Fire alarm device according to one of the preceding claims, characterized in that the threshold value circuit (22) can be switched several times with regard to its threshold value. is designed so that in the switching stage reached after a switch to a higher threshold value, compared to the previous switching stage, it only emits an output signal when an increase in line current occurs that is equal to the increase in line current (di) that can be generated by a single electronic detector (De) is greater than that line current which corresponds to the threshold value of the previous switching stage (FIG. 6). 8. Fire alarm device according to one of the preceding claims, characterized in that parallel to the electronic detectors (De) at least one manually operable detector (Dm) is connected to the wires (14, 16) of the line (Z ^, that the evaluation circuit has a has additional threshold value circuit (60) connected downstream of the measuring element (20), the threshold value (χ _Μ ) of which is higher than the highest threshold value (x ₂ b) to which the threshold value circuit (22) can be set that the manually operated detector (Dm) the line current increase (3di) caused when it is actuated is higher than the line current increase which corresponds to the threshold value (x _w ) of the additional threshold value circuit (60), and that a further alarm signal is generated by the output signal of the additional threshold value circuit (60) ( Fig. 1,2).