EP0971329A1 - Device for testing smoke detectors of the light diffusion type - Google Patents

Abstract

The smoke alarm has a measurement chamber (5) with a light pulse emitting measurement light source (6) and a measurement light receiver (7). The test arrangement has an adapter (1) contg. a test light source (3) that can be actuated synchronously with the light pulses from the measurement light source to illuminate the measurement light receiver with test light pulses. The adapter has a detector (2) that responds to the electromagnetic field produced by the current pulses of the measurement light source and that controls the test light source.

Description

The present invention relates to a device for checking the function of scattered light smoke detectors, which is a measuring chamber with a measuring light source emitting light pulses and have a measuring light receiver, with an adapter, which is synchronous with the Light pulses of the measuring light source actuable test light source for acting on the measuring light receiver with test light pulses.

The measuring chamber of scattered-light smoke detectors is known to be as tight as possible against light from shielded on the outside to make the detector largely immune to extraneous light. Yet this shielding cannot be absolute, because the detectors against the outside atmosphere must be open so that smoke can enter the measuring chamber. To the influence of interference To minimize the extraneous light entering the measuring chamber despite the shielding is Evaluation circuit of the detector designed so that the measuring light receiver only on such Light reacts within a defined time window after the triggering of the respective Light pulse of the measuring light source is received.

In the case of a detector tester described in EP-A-0 636 266 (US-A-5,523,744) mentioned type, the test light transmitter is actuated by a arranged in the detector tester additional light receiver, which receives a light pulse from the measuring light source triggers the test light source. Because of the shielding of the measuring chamber against The additional light receiver does not emit the light pulses in every relative position of the detector tester to the detector but can only receive in certain locations are with this Detector tester positioning means are provided that ensure that the detector tester is always in the same orientation in relation to the detector in the test position.

The measuring light source and the additional light receiver of the Detector tester as well as the test light source and the measurement light receiver defined relative positions one in which it is ensured that the light pulses of the measuring light source on the additional Light receiver and the light flashes of the test light source on the measuring light receiver reach. Since the positioning means indicate the presence of appropriate guide means the smoke detectors, this detector tester is only for detectors of a certain type usable and can not be used in principle on detectors without such guide means become.

The invention is now intended to provide a detector tester that is in any alignment position works perfectly compared to the detector to be tested and is therefore universal can be used and can be easily adapted to different detector types.

According to the invention, the object is achieved in that the adapter connects one to the responsive electromagnetic field generated by the current pulses of the measuring light source and the detector controlling the test light source.

In the detector tester according to the invention, the measuring light source is no longer used emitted light pulses detected as such, but by the triggering the light pulses Current pulses generated an electromagnetic field. Since this field is the detector on all sides and surrounds relatively homogeneously, the detector tester can light pulses in any orientation Detect against the detector.

This is a first preferred embodiment of the device according to the invention characterized in that said detector is formed by an induction coil.

A second preferred embodiment of the device according to the invention is thereby characterized in that the adapter has a prismatic, box-like shape and in the Kind of a remote control directed against the smoke detector to be tested or on the top of a smoke detector lying on a base is adjustable.

A third preferred embodiment of the device according to the invention is characterized in that that the adapter is a rotationally symmetrical, open at one end, rifle or has a can-like shape and can be placed on or above the detector to be tested is slidable, and that the induction coil is arranged on the inside of the adapter. Preferably is the induction coil near the edge on the open side of the adapter or arranged on the floor opposite the open side.

A fourth preferred embodiment of the device according to the invention is characterized in that that means are provided for reflecting the test light pulses into the measuring chamber are. These means for reflection of the test light pulses, which of course also means for their Scattering can ensure that the detector tester is in any orientation a sufficient proportion of the test light pulses directed towards the detector into the measuring chamber and arrives at the measuring light receiver.

A fifth preferred embodiment of the device according to the invention is characterized in that that the means mentioned for reflection of the test light pulses by one at the Reflective coating arranged on the inside of the adapter are formed.

The detector tester according to the invention can in principle be used for testing for any type of Scattered light detectors are used, so that usually for the detector test used relatively expensive test gas can be dispensed with. This not only results in cost savings but also enables a much faster check of entire detector lines because every detector is fully functional immediately after the test and not as with the Test with test gas has a measuring chamber filled with the test gas and thereby through Follow-up alarms blocked further testing.

The two versions of the adapter, either as a small box in the manner of a remote control, or as a box that can be slid over or placed on the detector are for different people Applications provided. The can shape is preferably always used there where detectors mounted on a ceiling need to be checked what is from the floor of the concerned Raumers from. In this case, the adapter is built into a hood-shaped housing, which is attached to a pipe socket that can be extended by extension pipes.

The adapter in the manner of a remote control is preferably used in test laboratories where the Detectors to be tested are not mounted on the ceiling but on a plate or on a test table are, or for detectors mounted inside devices or air ducts, which are for the can-shaped adapters are difficult to access.

Another preferred embodiment of the device according to the invention is characterized through an electronic circuit for synchronizing the triggering of the test light pulses with the light pulses of the measuring light source, which circuit a stage for fading of interference pulses from the signal supplied by the induction coil, which contains an amplifier and an electronically regulated voltage divider, with the regulated voltage divider automatically such a shift in the working point of the Amplifier takes place that the interference pulses are masked out by the pulses of the measuring light source caused measuring pulses are recognized correctly.

Fig. 1

eine schematische Darstellung eines erfindungsgemässen Melderprüfers; und

Fig. 2

ein Blockschema der Schaltung zur Synchronisierung der Mess- und der Prüf-Lichtquelle.

The invention is explained in more detail below with the aid of an exemplary embodiment and the drawings; it shows:

Fig. 1

a schematic representation of a detector tester according to the invention; and

Fig. 2

a block diagram of the circuit for synchronizing the measuring and the test light source.

The detector tester shown in Fig. 1 is used to check the function of smoke detectors on site, So usually from detectors mounted on the ceiling of a room, and is to this Purpose designed so that it is placed on the detector to be tested from above or over it can be pushed. The detector tester is particularly suitable for detectors whose Housing has approximately the shape of a spherical cap or a truncated cone. Such Detectors are, for example, in the international model protection registrations DM / 028 534 and DM / 034 103. This note is not limited to the detector types mentioned to understand; of course, the detector tester according to the invention with any minor adjustments can be used with practically all modern stray light smoke detectors.

As shown, the detector tester essentially consists of a rotationally symmetrical, open on one side, sleeve-shaped adapter 1, from one on the inside of the Adapters 1 arranged induction coil 2, from a short distance from the Edge of the adapter 1 on its open side arranged light source 3 and from a Area of the bottom of the adapter arranged electronics 4. The induction coil 2 can as shown in the figure, on the bottom of the adapter 1 or on its upper edge, for example at the level of the light source 3.

As is indicated in the figure by a scattered light smoke detector M, the detector tester is placed on the detector to be tested or, if necessary, pushed over it. For a more detailed description of the smoke detector M, reference is made to EP-A-0 636 266, EP-A-0 821 330 and to the scattered light detectors of the AlgoRex series ( AlgoRex - registered trademark of Cerberus AG).

sieht" der letztere zwar den genannten zentralen Bereich der Messkammer 5, nicht aber die Mess-Lichtquelle 6. Das Licht der Mess-Lichtquelle 6 wird durch in die Messkammer 5 eindringenden Rauch gestreut, und ein Teil dieses Streulichts fällt auf den Mess-Lichtempfänger 7.The smoke detector M has a measuring chamber 5 shielded from light from the outside with a measuring light source 6 and a measuring light receiver 7, the optical axes of which are angled to one another and intersect one another in a central region of the measuring chamber 5. The measuring light source 6 sends short, intense light pulses into the central area of the measuring chamber 5, whereby due to the chosen arrangement no light beams can go directly from the measuring light source 6 to the measuring light receiver 7. Therefore

the latter sees the central area of the measuring chamber 5, but not the measuring light source 6. The light from the measuring light source 6 is scattered by smoke entering the measuring chamber 5, and part of this scattered light falls on the measuring light receiver 7 .

Since the measuring chamber 5 must be designed in such a way that smoke can enter it even the light shielding of the measuring chamber should not be complete, so with one if also very small, extraneous light component within the measuring chamber 5 must be expected. The evaluation electronics are used to switch off any interference from this remaining ambient light of the detector M so designed that the measuring light receiver 7 only then from it received stray light reacts if this occurs within a certain time interval Emission of a light pulse by the measuring light source 6 arrives at it. The broadcast of a light pulse by the measuring light source 6 thus opens a time window in the evaluation electronics, so that received signals of the measuring light receiver generated only within this time window 7 are processed.

During the functional test of the smoke detector to be carried out with the detector tester shown M is the light pulses of the measuring light source 6 intermittent light of the following as Test light source superimposed light source 3 of the detector tester. These test light pulses get into the measuring chamber 5 of the smoke detector M and in this to the measuring light receiver 7; after the receipt of one or more test light pulses, the detector will generate an M alarm triggered, which is detected on the alarm indicator of the detector or in the assigned signaling center becomes. This alarm trigger serves as a criterion for the detector to be functional.

To ensure that the detector tester is aligned in any orientation Smoke detector M directs the largest possible proportion of the test light pulses into the measuring chamber 5 and arrives at the measuring light receiver 7, can be in the level of the test light source 3 strip-shaped area of the inner wall of the detector tester with a reflective coating 8 be provided.

The induction coil 2 detects that generated by each light pulse of the measuring light source 6 electromagnetic field and controls the test light source 3 so that it is within the stated Time window emits test light pulses. To bundle the electromagnetic Field on the induction coil 2 is the latter of a metallic open to the top Cylinder 9 surrounded by an electromagnetic on its upper face permeable film 10 can be covered. The film can also above the cylinder 9th be arranged.

The adapter 1 is installed in a hood-shaped housing 11 which is placed on a sleeve 12. In the latter, a pipe socket 13 is inserted, on which an extension pipe can be pushed. The detector can be checked up to a room height of around 7 m with several of these extension tubes that can be connected to one another by means of pipe clamps. The detector tester is powered either by batteries or by a power cable, with the battery compartment or the power supply unit being located on the lowest extension tube. This box-like device part, which also contains a switch for switching the detector tester on and off, is designated in FIG. 1 by the reference symbol BF. The housing 11 can also be connected to the pipe socket 13 via a fork-shaped adapter (not shown), as is the case with the detector testers for the AlgoRex detectors mentioned.

FIG. 2 shows a block diagram of the adapter 1 connected to the induction coil 2 Circuit 4, which is used to synchronize the test light source 3 with the measurement light source 6 serves. As shown, the circuit 4 contains one connected to the induction coil 2 first preamplifier stage 14, a high / low pass filter connected to this 15, a second preamplifier stage 16 connected to the filter 15, one to the latter connected output stage 17 and a stage 18 interacting with this bidirectionally Noise suppression and automatic gain control. At the final stage 17 is a active time filter 19 connected and to this a difference evaluation 20. The difference evaluation 20 is a stage 21 for generating the electrical pulse for triggering the Test light pulse connected downstream and this a voltage converter upstream of the test light source 3 22. The latter is preferably arranged in the device part BF (Fig. 1).

The test light source 3 is a flash lamp or flash tube, for example a xenon tube, formed, and the voltage converter 22 is used to provide the for the ignition of the Flash lamp required voltage. One of the voltage converter 22 is for lightning interference suppression serving connection 23 to the output stage 17 is provided.

The measuring light source 6 (FIG. 1) formed, for example, by an infrared diode (IRED) transmits a light pulse at regular intervals of, for example, 1 to 3 seconds, whereby in the induction coil 2, a voltage pulse MP referred to below as the measuring pulse of about 100 µs duration is induced. This measuring pulse is very small and is a few Millivolts.

It goes without saying that the induction coil 2 is not only caused by the pulses of the measuring light source Voltage pulses induced, but also by the different communication currents on the detector lines. They differ from these interference pulses denoted by SP the measuring pulses MP essentially by their significantly lower frequency and by their duration. The voltage pulses induced in the induction coil 2 are in the first preamplifier stage 14 amplified and then the coarsest interference pulses in the high / low pass filter 15 filtered out.

After further amplification in the second preamplifier stage 16, the signal reaches the Power stage 17 and in stage 18 for glitch suppression and automatic gain control. At this stage, which is essentially an amplifier, an electronically controlled one Includes voltage divider and a storage capacitor, by a shift (offset) the operating point of the amplifier through the adjustable resistance, the measuring pulses MP and the interference pulses SP shifted to different sides with respect to the zero line, as shown the measuring pulses MP in the negative and the interference pulses SP in the positive range. Thereby the interference pulses SP can simply be hidden. Through the voltage divider automatic gain control.

After the suppression of the interference pulses SP in stage 18 there is one of interference pulses in the final stage 17 largely cleaned and formed by a characteristic double pulse Measuring pulse MP available, which has a steep rising edge, which subsequently leads to Triggering the flash (test light pulse) of the test light source 3 is used.

Since it cannot be ruled out that the output signal of the output stage 18 is still is contaminated by interference pulses, a further smoothing and takes place in the active time window 19 Attenuation of any disturbances that may still be present, as a result of which the measuring pulse MP is shown sawtooth-like shape. The flash is triggered when the measuring pulse MP exceeds a certain threshold. To prevent the flash from being hit by a the existing interference pulse is triggered, the threshold value must not be too low; on the other hand it must also not be too large, so that it also contains weaker light pulses from the measuring light source corresponding smaller measuring pulses can be triggered. As shown becomes the threshold value named and designated SW in the differential evaluation stage 20 placed in the middle of the rising edge.

When the threshold value SW is exceeded by the rising edge of the measuring pulse MP, in the stage 21 generates a pulse for triggering the test light source (flash lamp) 3. That pulse has the rectangular shape shown and it preferably lasts somewhat longer than the measuring pulse MP, for example about 200 µs.

The lightning interference suppression, which is used to suppress the disruptive influence of the lightning Test light source 3 on the gain control is used because this for a short time after Flash trigger does not work as desired, is that the level 18 included Regulation is locked for the duration of the flash.

As an alternative to the shape shown in FIG. 1, the adapter can also have the shape of an elongated prism in the manner of a remote control for electronic devices or for door openers for garage doors. Such an adapter is preferably used for testing smoke detectors in laboratories or in difficult-to-access devices or ventilation ducts. This adapter is used to check detectors either at a short distance from the detectors on them, or you place the adapter on the top of the detectors if they are on a horizontal plate or a horizontal table with the top facing up. Practical tests have shown that with this position of the adapter even with detectors with a straight line Kuppe "the test light pulses emitted by the test light source reach the measuring light receiver, which is obviously caused by scattering the test light pulses on particles contained in the room air.

The adapter contains at its end facing the detector to be tested during the test an exit window for the passage of the test light pulses and an infrared filter for them, see above that the flashes of light are no longer perceived as disturbing.

Claims (12)

Device for checking the function of scattered light smoke detectors (M), which one Measuring chamber (5) with a measuring light source (6) emitting light pulses and a measuring light receiver (7), with an adapter (1), which is synchronous with the light pulses the test light source (3) which can be actuated to act on the measurement light receiver (7) with test light pulses, characterized in that the adapter (1) one to the electromagnetic generated by the current pulses of the measuring light source (6) Field responsive and the test light source (3) controlling detector (2). Apparatus according to claim 1, characterized in that said detector by an induction coil (2) is formed. Device according to claim 1 or 2, characterized in that the adapter has a prismatic, has box-like shape and in the manner of a remote control against the testing smoke detector (M) can be aimed or on the tip of a lying on a surface Smoke detector is adjustable. Apparatus according to claim 3, characterized in that the adapter on its to testing detector (M) at the testing end facing a window for the passage of the Contains test light pulses and an infrared filter for them. Device according to claim 1, characterized in that the adapter (1) is a rotationally symmetrical, has an open, can-like or can-like shape at one end and on the detector to be tested (M) can be put on or pushed over it, and that the induction coil (2) is arranged on the inside of the adapter (1). Apparatus according to claim 5, characterized in that the induction coil (2) in the Close to the edge on the open side of the adapter (1) or on the opposite side of the open side Floor is arranged. Apparatus according to claim 5, characterized in that means (8) for reflecting the Test light pulses are provided in the measuring chamber (5), and that this means by one reflecting coating (8) arranged on the inside of the adapter (1). Apparatus according to claim 7, characterized in that the test light source (3) in the Arranged near the edge on the open side of the adapter (1) and the reflective Covering (8) is formed by a strip-shaped region adjacent to the said edge is. Apparatus according to claim 6, characterized in that the induction coil (2) containing bottom part of the adapter (1) is covered by a film (10). Device according to claim 1, characterized in that the test light source (3) by a flash lamp is formed. Device according to one of claims 3 to 10, characterized by an electronic Circuit (4) for synchronizing the triggering of the test light pulses with the light pulses the measuring light source (6), which circuit (4) has a stage (18) for suppressing interference pulses (SP) from the signal supplied by the induction coil (2), which has a Includes amplifier and an electronically controlled voltage divider, being regulated by the Voltage divider automatically such a shift in the working point of the Amplifier takes place that the interference pulses (SP) are masked out and that by the pulses of the Measuring light source (6) caused measuring pulses (MP) can be recognized properly. Apparatus according to claim 11, characterized in that during the duration of each Test light pulse inhibits the controller of stage (18) to suppress interference pulses he follows.

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