EP0636266B1 - Device for testing smoke detectors - Google Patents

Abstract

PCT No. PCT/CH94/00010 Sec. 371 Date Oct. 11, 1994 Sec. 102(e) Date Oct. 11, 1994 PCT Filed Jan. 21, 1994 PCT Pub. No. WO94/18653 PCT Pub. Date Aug. 18, 1994.A device (7) for testing the operation of smoke detectors (3) has a housing (1) which is open at one end and can be placed over the smoke detector (3). A test light source (5) in the housing provides light pulses which radiate into the inside of the smoke detector (3) under test. The test device also has a test light detector (4) that receives light coming from the smoke-indicating light source (15) of the smoke detector (3) and controls the test light source (5) in relation to the received light. The light pulse of the test light source (5) is received by the smoke-indicating light detector (14) of the smoke detector (3). By checking if the smoke detector (3) goes into the alarm state, it can be ascertained whether it is in an operational condition.

Description

The invention relates to a device for testing the function of smoke detectors the preamble of claim 1. Such smoke detectors are generally known, they are used in fire alarm systems for the early detection of fires in the event of a fire detect smoke particles or aerosols and if necessary send a signal to manage a central process unit in which the signals are evaluated.

Optical smoke detectors based on the scattered light principle contain a radiation source and a radiation receiver arranged outside the direct radiation area of the radiation source, the presence of smoke or fire aerosol in the radiation area (Measuring chamber) is acted upon by scattered radiation and depending on the Strength of the scattered radiation emits electrical output signals that are in a smoke detector existing electronic circuit for alarm or evaluated to the central Process unit to be forwarded. To avoid interference from extraneous light the light sources often work in pulses, cf. e.g. those in EP-B1-0'079'010 described smoke alarm system.

Fire alarm systems must be ready for operation over longer periods. During this Time the smoke detectors are the harmful effects of the surrounding atmosphere, e.g. Exposed to dust or corrosive fumes; in addition, the electronic Components, in particular the radiation source and the radiation receiver due to aging decrease in quality. It is therefore necessary to ensure the functionality of the Check smoke detectors at regular intervals.

In practice, this check was usually carried out by placing a smoke detector under the small test fire was lit, which produced smoke that penetrated into the detector could and made him respond. The test was also carried out by a burning fuse, e.g. on a pole, placed directly under the detector (see e.g. U.S. Patent 4,271,693). Aside from the fact that these procedures are pretty are cumbersome, they often brought soiling of the detectors with them could lead to inoperability.

Attempts have therefore been made to remove smoke from liquid droplets, e.g. artificially generated Fog, to replace, as such aerosols affect the smoke detector in the same way like smoke from fire. For example, you have a mist of water droplets generated and used for testing. The one that is reflected on the inner surfaces Water skin makes the detector inoperable for a long time.

Mixtures of halogenated hydrocarbons have proven to be the best (Propellants), which have a suitable boiling point and which from suitable, in so-called detector testers arranged storage containers directly into the smoke detectors are blown (see e.g. DE-B2-20'54'027). Due to the pressure loss when exiting A sufficient amount of aerosol is created to test the smoke detectors. By the The high vapor pressure of the halogenated hydrocarbons evaporates the blowing agent within a short time and the operational readiness of the detectors is not impaired.

A suitable for testing smoke detectors with halogenated hydrocarbons Detector tester consists of an open on one side that can be put over the smoke detector Housing whose volume is at least twice the volume of the smoke detector is, as well as by a container connected to the housing, which under pressure contains liquefied propellant and the one with the housing put on by hand or Automatically actuated spray valve, the nozzle of which leads into the interior of the housing.

Because of the harmful properties of halogenated hydrocarbons they can no longer be used. Those that can be used as replacements Substances are mostly flammable, toxic, corrosive and / or expensive (cf. Nachr. Chem. Tech. Lab. 40 [1992], No. 12, p. 1398).

There are other test methods for fire alarm systems with optical smoke detectors known that work without the use of test gases. In general also uses processes that allow smoke to enter the smoke detector simulate. Here, e.g. an additional light source, which light directly on the Radiation receiver throws in the smoke detector to simulate the occurrence of stray light (U.S. Patent 2,627,064). In US-PS-3,585,621 a test device is described in which to check the Light source is used opposite a calibration piece, the scattered light on the light receiver throws and e.g. simulates a smoke concentration of 4%. In GB-PS-1,079,929 the test of the optical smoke detectors is carried out by an alarm simulation (Scattered light) by inserting a flag into the beam path.

It can also measure the voltage at the input of the threshold detector using a switch be raised to a value just below the response voltage (JP-PA-46-12199); the peaks that are normally far below the response threshold the diffuse stray light is raised so far that an alarm is given during the test becomes; the simultaneous function test of flash lamp, photocell, amplifier and circuit possible.

US-A-4,306,230 discloses a photoelectric smoke detector for displaying both Alarm as well as fault conditions are revealed, which one from a light source and a photosensitive sensor arranged outside the direct beam path of the light source Element existing detection device, which depending on a first outputs an output signal due to the presence of smoke, having. A second detection device is provided in the smoke detector enables a fault condition (contamination of the surfaces of the light source or light-sensitive element) through an opening in the housing the detector a predetermined amount of light from the light source onto the photosensitive Element is dropped. When the amount of light falling through the opening does not trigger a signal within a certain range, this is a malfunction of the Detector displayed.

EP-A1-0'122'5489 describes a method for testing photoelectric smoke detectors described, in addition in the measuring chamber of the stray light smoke detector a test light receiver for the smoke detection light source and the smoke detection light receiver, which receives light directly from the light source, and a test light source, which directly depending on the output signal of the test light receiver on the smoke detection light receiver, are provided. With this procedure the functioning of the smoke detector is constantly monitored from a control center, the detector is tested to determine whether it is working properly and whether it is sensitive is within the normal range.

The disadvantage of all these test methods is that in each individual smoke detector Means for testing the detectors must be provided, which results in a significant The fire alarm system becomes more expensive.

JP-PA-53-99899 describes a device for the functional test of optical smoke detectors described, in which a part of the housing that the measuring chamber against the Shields outside atmosphere, made of rubber or an elastic body, e.g. one Sponge exists. The elastic body is covered with a flat plate, which in the Has an opening in the middle. A device consisting of four arms is used for testing, which is put over the detector; there is one in the center of the four arms Needle that penetrates through the rubber into the detector's measuring chamber and the occurrence of stray light simulated in the chamber. That means, on or in the detectors constructive means are provided which enable the functional test.

Starting from this prior art, the invention is based on the object Device to test the function of smoke detectors to create the disadvantages avoids the known devices for functional testing of smoke detectors and which in particular enables the detectors to be checked at the installation site without Means must be used which damage the detector or the environment are able. Another object of the invention is to test the detector to be able to carry out without constructive means on or in the individual detectors must be attached.

These tasks are performed on a device for testing the function of smoke detectors of the type mentioned by the characterizing features of claim 1 solved. Preferred embodiments and refinements of the invention are in the dependent claims.

The device according to the invention takes advantage of the fact that a stray light smoke detector largely against the intrusion of light from the environment in shielded the detector, however, this shielding is not absolute as the detector must be open to the outside atmosphere so that smoke can enter the measuring chamber can. By scattering the light on components inside the detector, light from the detector's light source, and vice versa, from outside forth light can be radiated into the interior of the detector by scattering on the Detector light receiver arrives.

In a preferred embodiment of the device according to the invention A test light receiver is provided inside the housing and is arranged in such a way that it emits light from the smoke detector's smoke detection light source can receive. The output signal of this test light receiver controls the test light source in such a way that this emits a light pulse into the interior of the device under test Smoke detector that emits from the smoke detector light source of the smoke detector emitted light pulse corresponds.

In a further preferred embodiment of the device according to the invention are positioning means in the housing, at its upper edge, distributed over the circumference provided, by which the device is to be checked when slipped over one Smoke detectors in interaction with guide devices on the smoke detector is aligned so that the test light source is aligned with the smoke detection light receiver and the test light receiver with respect to the smoke detection light source are in the same position. This ensures that when testing different smoke detectors always have the same measurement conditions. Preferably are the guide means provided on the smoke detector by another Outside arranged guide nose and the positioning means by this Protrusions and guide grooves are formed.

According to a further preferred embodiment of the device according to the invention an extension is formed axially at the closed end of the housing, on which a rod can be attached. These are preferably hollow and arbitrary Extendable rod is used to test smoke detectors that are higher on the ceiling Rooms are attached.

A further preferred embodiment of the device according to the invention is thereby characterized in that control electronics for controlling the test light source and Evaluation of the signals of the test light receiver is provided, the test light receiver when receiving from the smoke detection light source Light generates a signal which, when a predetermined value is exceeded in the test light source triggers a light pulse and that the control electronics blocking means to prevent triggering a further light pulse from the test light source through the light impulse it emits itself. A possibility to the latter is, for example, the electrical signal of the test light receiver block until another pulse of light from the smoke detection light source going out.

Fig. 1

einen Längsschnitt durch eine erfindungsgemässe Vorrichtung zur Funktionsprüfung von Rauchmeldern; und

Fig. 2

einen Querschnitt durch eine Variante der Vorrichtung von Fig. 1 entlang der Linie A-B.

The invention is explained in more detail below with reference to exemplary embodiments shown in the drawings; it shows:

Fig. 1

a longitudinal section through an inventive device for functional testing of smoke detectors; and

Fig. 2

a cross section through a variant of the device of FIG. 1 along the line AB.

In the drawings, only those parts of the device for the functional test of Smoke detectors are shown for easy understanding of the underlying principles and terms are required by those skilled in the art. The test device is as follows referred to in the description as "detector tester". In the description and in the claims are consistently of "light", "light" receivers and "light" sources spoken. It should be noted that the term "light" also invisible light, e.g. Infrared or ultraviolet radiation, i.e. basically any electromagnetic radiation commonly used in optical smoke detectors is to be understood.

The detector tester 7 shown in Fig. 1 is shown in the position in which it over a smoke detector 3 attached to a ceiling 6; the smoke detector is in Side view shown. The detector tester 7 consists essentially of a rotationally symmetrical, cylindrical housing 1, the bottom of a peg-shaped extension 2, on which a rod can be attached to test smoke detector 3 to be able to, which are attached to ceilings 6 in high rooms.

A test light source 5 is attached to the inner wall of the housing 1. At the top There are several projections 8 distributed over the circumference of the housing 1, and guide grooves 9 provided therein, which when the detector tester is slipped on via a smoke detector 3 to be tested in cooperation with an attached to it Guide nose 11 ensure that the test light source 5 is in the detector tester 7 relative to the smoke detection light receiver 14 of the smoke detector 3 always in the same position so that when testing different smoke detectors 3 always the same conditions prevail.

The housing 1 can be made of any material, expediently it is made of a suitable plastic or for reasons of weight saving made of light metal. On the underside of the housing 1 is in a separate compartment the electronics 12 of the detector tester 7, which are used to operate the test light source 5 required battery, and the like. The bottom of the housing 1 and that Compartment with electronics 12 have an opening 23 through which alarm indicator 22 of the smoke detector 3 can be observed.

To test a smoke detector 3, the detector tester 7 is positioned above the smoke detector 3 that the guide grooves 9 slide over the guide lug 11 on the smoke detector 3 and the projections 8 of the detector tester 7 rest on the housing of the smoke detector 3. By starting up the test light source 5, a pulsed light beam is emitted into the interior of the smoke detector 3 and it is by observing the alarm indicator 22 am Smoke detector 3 or in a signal center (not shown) determined whether the smoke detector 3 is functional.

Fig. 2 shows a section along the line A-B of Fig. 1 shows a cross section through a preferred embodiment of a detector tester 7, in which on the inner wall of the Housing 1 additionally a test light receiver 4 is provided. This test light receiver is shown in dashed lines in Fig. 1. The smoke detector 3 contains in his Interior in a known manner, a smoke detection light source 15, a smoke detection light receiver 14 and means indicated by light shielding plates 24 which prevent light directly from the smoke detection light source 15 onto the smoke detection light receiver 14 falls.

The alignment of the detector tester 7 relative to the smoke detector 3 is the same as that of the Embodiment of Fig. 1 by the projections 8 and guide grooves 9, which with the Interact with the guide lug 11 on the smoke detector 3. This is where the test light source is 5 of the detector tester 7 with respect to the smoke detection light receiver 14 and the test light receiver 4 with respect to the smoke detection light source 15 of the Smoke detector 3 always in the same position, which means the same measurement conditions are guaranteed.

Electronics 12 (FIG. 1) includes an amplifier / bandpass filter (not shown) for Amplification, filtering and evaluation of that emitted by the test light receiver 4 electrical signal, and electronic means for controlling the test light source 5.

During the test process, the pulsed light from the smoke detection light source 15 arrives by scattering on components of the smoke detector 3 out of the detector and stands out the test light receiver 4 of the detector tester 7. The test light receiver 4 gives in Depending on the incident light, an electrical output signal from the amplifier / bandpass filter the electronics 12 is amplified. The electronics 12 also contains Means for comparing the size of this signal with a predetermined threshold. If the output signal of the amplifier exceeds this threshold, then the test light source 5 is driven and emits a light pulse that of the smoke detection light source 15 of the smoke detector 3 partially covered over time. This light pulse gets into the interior of the detector and by scattering on components of the smoke detector 3 falls on the smoke detection light receiver 14. After one or more receptions Such a light pulse triggers an alarm signal in smoke detector 3. On the alarm indicator 22 (or in the signaling center) can affect the functionality of the smoke detector 3 can be recognized.

The electronics 12 also includes switching elements that prevent light from the Test light source 5, which falls on the test light receiver 4 to trigger again the test light source 5 leads. This can be achieved, for example, by the fact that after the first activation of the test light source 5, the output signal of the test light receiver 4 is blocked for a time shorter than the period between two Light pulses from the measuring light source 15 of the smoke detector 3.

Means can additionally be provided in the housing 1, which allow a Remove smoke detector 3 from its socket and reinsert it. This eliminates the need the use of a special device for removing and inserting Smoke detectors (so-called detector pickers).

In order to also be able to test thermal smoke detectors, the hollow ones can be Extension 2 of the housing 1, a fan and a heating coil are attached.

Claims (8)

1. Device for testing the operation of optical smoke detectors employing the scattered-light principle, which have a smoke-indicating light source (15) and a smoke-indicating light detector (14), with a housing (1) open at one end, which can be placed over the smoke detector (3) under test, in which means are provided, with which the occurrence of fire parameters is simulated inside the smoke detector (3), characterised by a test light source (5) provided inside the housing (1) and arranged so that light emitted from it can be received by the smoke-indicating light detector (14) of the smoke detector (3).
2. Device according to Claim 1, characterised by a test light detector (4) provided inside the housing (1) and arranged so that it can receive light emitted by the smoke-indicating light source (15) of the smoke detector (3).
3. Device according to Claim 2, characterised in that in the housing (1), at its upper edge, positioning means (8, 9) are provided and distributed over its periphery, by which the device when placed over a smoke detector (3) under test, in conjunction with guide means (11) provided on the smoke detector, is aligned so that the test light source (5) is in the same position with respect to the smoke-indicating light detector (14) and the test light detector (4) is in the same position with respect to the smoke indicating light-source (15).
4. Device according to Claim 3, characterised in that the guide means provided on the smoke detector (3) are formed by a guide lug (11) arranged on its outer side, and that the positioning means are formed by projections (8) and guide slots (9) making contact with this guide lug (11).
5. Device according to one of Claims 1 to 4, characterised in that at the closed end of the housing (1) an axial extension (2) is formed, onto which a rod can be plugged.
6. Device according to one of Claims 2 to 4, characterised in that an electronic control unit (12) is provided for triggering the test light source (5) and for evaluating the signals of the test light detector (4), wherein on receipt of light emitted by the smoke-indicating light source (15) a signal is generated by the test light detector (4), which triggers a light pulse when a predetermined value in the test light source (5) is exceeded, and that the electronic control unit contains blocking means for preventing the triggering of a further light pulse of the test light source by the light pulse emitted by the test light source itself.
7. Device according to Claim 6 characterised in that said blocking means produce a blocking of the output signal of the test light detector (4) for a certain time after the first triggering of the test light source (5).
8. Device according to one of Claims 1 to 4, characterised in that ventilation means are arranged in or on the housing (1) by which an air-stream can be blown into the smoke detector under test, and that means for heating the air-stream are provided.

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