DE102011108390B4 - Method of making an open type smoke detector - Google Patents

Abstract

A method of making an open type smoke detector having at least one light emitting element and at least one light sensing element in an open housing and a power supply unit and a control unit, the method comprising a calibration procedure comprising the steps of: a) providing and operating the smoke detector in FIG a large room, together with a calibrated smoke density meter and in conjunction with a calibration control unit via a bidirectional communication channel and optionally to the calibrated smoke density meter; b) Gradually filling the room with smoke; c) in response to detection of a first predetermined value of smoke density by the calibrated smoke density meter, directing the smoke detector to store its own current detection signal or transmitting it to the calibration control unit, and instructing the calibrated smoke density meter to transmit its signal to d d) performing a comparison between the detection signals of the smoke detector and the calibrated smoke density meter, and processor-based adjustment of the current in a current stabilizer of the power supply unit of the smoke detector such that its detection signal is made equal to the detection signal of the calibrated smoke density meter, to obtain a first calibrated measuring point of the smoke detector, and storing the corresponding adjusted current value, ande) providing a calibrated operation of the smoke detector using the stored calibration table, characterized by f) repeating steps c) and d) a predetermined number of times with increasing Smoke density in the room to obtain further calibrated measuring points and corresponding current values of the smoke detector and thus a calibration table and to store in a memory of the smoke detector, and comprising the Obtaining corresponding smoke detector signals at at least two different temperatures in a vanishing or constant smoke density atmosphere, comparing the smoke detector signals, adjusting the power supply so that the smoke detector signals become the same at the different temperatures, storing the respective T-adjusted current values in relation to different temperatures, and providing a T-calibrated operation using the stored T-adjusted current values.

Description

The invention relates, on the one hand, to a method for producing an open-type smoke detector ("smoke detector") comprising at least one light emitting element and at least one light sensing element in an open housing and a power supply unit and a control unit, the method comprising a calibration procedure. It further relates to an open type smoke detector comprising a control unit including power supply and signal processing electronics and at least one remote detection unit having at least one light emitting element and at least one light sensing element in an open housing, and a smoke detection system.

The technical field of smoke detectors is characterized by a high level of sophistication and includes various types of smoke detectors, most notably those of the closed type (having a substantially closed detection chamber) and those of the open type (having a space open housing).

From the Applicant's point of view, in the extensive state of the art, insofar as it relates to individual smoke detectors, the following publications are worth mentioning in particular: WO2005069242 . GB2410085 . DE10104861 . DE10118913 . DE19951403 . WO2008017698 . US2004 / 0066512 . US6218950 . US2008 / 0246623 . DE19809896 . US2002 / 0080040 . WO9916033 . US2006 / 0202847 . WO2004032083 . WO1995004338 . WO2006024960 . GB2319604 and EP1619640 ,

Of the patent literature dealing with more complex smoke detection systems, the following references appear to the applicant as worth mentioning: US6075447 . EP1555642 . GB2357358 . WO1993015483 . DE19740922 . GB2293472 . US6195011 and US20050219045 ,

In the WO 2005069242 a smoke detector is described which operates according to the scattered radiation principle and comprises at least one radiation transmitter and at least one radiation receiver whose radiation paths penetrate a scattering volume. Two pairs of radiation transmitters / receivers are used which form two separate scattering volumes at the same distance from the detector surface. The fire detector also includes a pair of radiation transmitters / radiation receivers for dust compensation.

In the GB 2410085 a smoke detector is described which has a shielding cover window to protect the radiation transmitter and radiation receiver. There is a special feature described in the cover window, which excludes waveguiding effects in the window and prevents light from passing directly to the radiation receiver, without being scattered in the controlled volume.

In the DE 10104861 a smoke detector with detection chamber is described which operates according to the scattered and transmitted light radiation principles. This detector is available as a variant for detection in a free space litter volume without a detection chamber. The detector has automatic compensation for stable levels of smoke, dust on its surface.

In the DE 10118913 For example, there is described a free-space scattered light type smoke detector having a plurality of detection volumes organized by a system of lenses and radiation emitter and radiation receiver arrays.

In the WO 2008017698 a smoke detector is described which uses two different wavelengths for smoke detection and detection between different types of smoke. Two different receivers are directed at different angles on the transmitter central axis.

In the US 20040066512 a smoke detector is described with a smoke chamber having two emitting diodes in different spectral ranges, preferably for IR (about 880 nm) and blue light (about 400 nm), and two receiving diodes. The transmitting and receiving diodes are at different angles on a flat surface so that forwardly scattered radiation reaches a receiving diode and backscattered radiation reaches the other receiving diode. The detector has good performance for both white and black smoke.

In the US 20080246623 In the US Pat. No. 4,843,809, an open type smoke detector is described in which two emission elements are arranged at different angles and polarization planes are used to distinguish between different types of scattered radiation from the controlled region.

In the EP 1619640 a smoke detector of the open type is described with a very simple circuit arrangement in which two signals from two emission diodes are measured at different angles. The main process steps are performed by a microprocessor. There is also a temperature sensor provided.

From the publication DE 694 32 071 T2 a method according to the preamble of claim 1 is known.

The publication US 4 093 867 A describes a device for the automatic calibration and testing of smoke detectors and described a method carried out with such a device, wherein a feedback to a calibrated detector is provided. This method also essentially comprises the steps of the preamble of claim 1.

From the US 5 552 765 A there is known a smoke detector having an individually stored region of suitable sensitivity, and the reference also teaches a calibration method which takes into account a range of smoke density values and repeats the smoke density measurement at different smoke densities to ultimately arrive at the stored sensitivity range.

The JP 2011-007529 A also describes a method and apparatus for calibrating a smoke detector.

The invention has for its object to provide a method for producing a smoke detector, which allows efficient deployment of flexible and diverse conditions usable and this reliable and precise working smoke detectors. Furthermore, the object of the invention is to provide a flexible smoke detector which can be used efficiently in various detection systems and a correspondingly flexible and efficient detection system.

The first object is achieved by a method having the features of claim 1 and the latter object by a smoke detector with the features of claim 7bzw. solved by a smoke detection system with the features of claim 10. Advantageous further developments of the inventive concept are the subject of the respective dependent claims.

The invention includes in its method aspect the idea of providing and operating the smoke detector - preferably simultaneously a plurality of smoke detectors - in a large space, together with a calibrated smoke density meter and in connection to a calibration control unit via a bidirectional communication channel and optionally to the calibrated smoke density meter on. It is further contemplated by this invention to successively fill the space with smoke and in response to detection by the calibrated smoke density meter of a first predetermined value of smoke density, instructing the smoke detector to store its own current detection signal or transmit it to the calibration Control unit and instructing the calibrated smoke density meter to transmit its signal to the smoke detector or to the calibration control unit.

This data transfer step is followed by making a comparison between the detection signals of the smoke detector and the calibrated smoke density meter, accompanied by an adjustment of the power supply unit of the smoke detector such that its detection signal is made equal to the detection signal of the calibrated smoke density meter to a first calibrated measuring point of Receive smoke detector, and storing the corresponding adjusted current values of the power supply unit. The method includes repeating the steps of data transmission, data comparison, and adjustment of the power supply unit a predetermined number of times to obtain and store further calibrated measurement points and corresponding sets of current values (hereinafter also "power supply parameters") of the smoke detector, and finally Providing a calibration table of the smoke detector using the stored sets of current values.

The claimed method includes obtaining respective smoke detector signals at at least two different temperatures in a vanishing or constant smoke density atmosphere, comparing the smoke detector signals, adjusting the power supply so that the smoke detector signals at the different temperatures become equal, storing the respective T-aligned ones Current values in relation to the different temperatures, and providing a T-calibrated operation using the stored T-adjusted current values.

An advantageous embodiment of the method provides for a fine calibration, which starts from the calibration procedure explained above and proceeds with constant removal of the smoke from the test room. The embodiment includes repeating the steps of data transmission, data comparison, and adjustment of the power supply unit a predetermined number of times during the gradual reduction in smoke density to obtain and store a number of finely calibrated measurement points and corresponding sets of refined current values. The design eventually results in providing a second calibrated operation of the smoke detector using the stored sets of refined current values.

To ensure a high practical suitability of the operating parameters, the smoke is obtained by burning a real sample in the room and removed from the room by operating a mechanical suction device.

An alternative, simplified procedure provides, instead of a detector-specific calibration procedure, the implementation of a calibrated operation using stored sets of current values obtained by a method according to one of the preceding claims for at least one other smoke detector. In one embodiment of this variant, the method includes a replacement calibration procedure using a smoke density equivalent (such as glass).

The smoke detector proposed according to the apparatus aspect of the present application is based on the idea of a structural separation between the power supply and signal processing components of a smoke detector and its actual detector arrangement. It thus comprises a control unit containing power supply and signal processing electronics and at least one remote detector unit having at least one light emitting element and at least one light sensing element in an open housing and a bi-directional communication link (a first plane) between the remote detector unit and the detector units and the control unit. In this case, in particular, the communication link of the first level has an optical fiber connection or radio connection.

A communication technology advantageously constructed embodiment is characterized in that the communication link of the first level has a serial connection between the control unit and the remote detector units, wherein only a portion of the remote detector units, preferably only a remote detector unit, is connected directly to the control unit during each of the remaining remote detector units is connected to the controller via a directly connected remote detector unit.

The proposed smoke detection system comprises a plurality of the above-described smoke detectors and a system control station, and a bidirectional communication link (a third level) between at least one of the smoke detectors and the system control station.

In an expedient embodiment of this system, the smoke detector control units are interconnected by a wired bidirectional communication link (a second level), and only a portion of the control units, preferably only one control unit, is directly connected to the system control station, while the remaining control units are directly connected connected control unit are connected to the system control station. In this case, the third level communication connection is preferably an optical fiber or radio connection based on the IP or Ethernet protocol.

In a particularly practical embodiment of the system, the system control station is connected to the control units of the smoke detectors and the temperature detectors and / or flame detectors and / or combined detectors in a user-defined configuration. It has inputs for receiving signals from all connected units and detectors, as well as a central processing unit for summarizing and evaluating signal processing of the received signals, in particular including statistical analysis and / or data filtering for noise removal, and for outputting a system output signal Result of this processing is formed.

• - Senkung der Möglichkeit falscher Alarme.
• - Anheben der Empfindlichkeit des Melders für echten Rauch.
• - Bereitstellen einer schnelleren Erfassung in frühen Brandstadien.
• - Garantieren einer Immunität gegen optische Signale und Funkrauschsignale
• - Erhöhen der Raucherfassungsstabilität unter schwierigen Bedingungen, einschließlich Lichtstrahlung mit hohem Pegel und Hindernissen im Erfassungsbereich.
• - Bereitstellen präziser Daten an den Benutzer, z.B. Rauchdichtedaten für technologische Messung und Steuersysteme.
• - Ausschließen von Störungen, die z.B. durch zufälligen Zigarettenrauch oder beständigen Rauch aus Waldbränden verursacht werden.
• - Überwachung der Rauchdichteverteilung im Inneren des gesamten Gebäudes für eine sichere Evakuierung von Menschen.
• - Einführen einer ultra-schnellen Branderfassung auf Grundlage einer Bestätigung verschiedener Arten von Meldern (Rauch, UV-Flammen, IR-Flammen, Temperatur)
• - Bereitstellen eines besseren Staubausgleichs.
• - Erweiterung des Betriebstemperaturbereichs des Melders.
• - Sicherstellen der Sicherheit menschlicher Augen in allen Betriebsarten. Energieeinsparung.

With the invention, at least in certain advantageous embodiments, one or more of the following advantageous effects can be achieved:

• - Lowering the possibility of false alarms.
• - Increasing the sensitivity of the detector for real smoke.
• - Provide a faster detection in early fire stages.
• - Guarantee immunity to optical signals and radio noise signals
• Increase the smoke detection stability under severe conditions, including high-level light radiation and obstacles in the detection area.
• - Provide accurate data to the user, eg smoke density data for technological measurement and control systems.
• - Excluding disorders caused, for example, by accidental cigarette smoke or constant smoke from forest fires.
• - Monitoring the smoke density distribution inside the entire building for safe evacuation of people.
• - Introduce ultra-fast fire detection based on confirmation of various types of detectors (smoke, UV flames, IR flames, temperature)
• - Provide a better dust balance.
• - Extension of the operating temperature range of the detector.
• - Ensure the safety of human eyes in all modes. Energy saving.

• 1 ein Funktionsdiagram eines Ausführungsbeispiels des Rauchdetektors,
• 2 eine Realisierungs-Variante der Spannungsstabilisierungsmittel beim Rauchdetektor nach 1,
• 3 eine detaillierte Darstellung von analogen und digitalen Baugruppen des Rauchdetektors nach 1,
• 4 eine Prinzipskizze zur Erläuterung einer beispielhaften geometrischen Konfiguration wesentlicher Elemente des Rauchdetektors,
• 5 eine weitere Darstellung, in Art einer perspektivischen Darstellung, zur Erläuterung der geometrischen Konfiguration,
• 6 eine kombinierte Darstellung zur weiteren Erläuterung der geometrischen Konfiguration,
• 7A bis 7C weitere Darstellungen zur Erläuterung des mechanischen Aufbaus einer Ausführungsform des erfindungsgemäßen Rauchdetektors,
• 8 eine Prinzipskizze der geometrischen Konfiguration einer weiteren Ausführungsform,
• 9 eine weitere Darstellung, in Art einer perspektivischen Darstellung, zur Erläuterung dieser geometrischen Konfiguration,
• 10 eine kombinierte Darstellung zur weiteren Erläuterung der geometrischen Konfiguration gemäß 9,
• 11 eine kombinierte Darstellung einer gegenüber 10 modifizierten Ausführungsform,
• 12 eine Prinzipskizze der geometrischen Konfiguration einer weiteren Ausführungsform,
• 13 eine Prinzipskizze der geometrischen Konfiguration einer weiteren Ausführungsform,
• 14 eine Prinzipskizze der geometrischen Konfiguration einer weiteren Ausführungsform,
• 15 eine Prinzipskizze der geometrischen Konfiguration einer weiteren Ausführungsform,
• 16 eine Prinzipskizze der geometrischen Konfiguration einer weiteren Ausführungsform,
• 17 eine Prinzipdarstellung eines mehrteilig aufgebauten Rauchdetektors als Teil eines Rauchdetektionssystems,
• 18 eine weitere Prinzipdarstellung eines mehrteilig aufgebauten Rauchdetektors als Teil eines Rauchdetektionssystems und
• 19 eine Prinzipskizze einer Ausführungsform eines neuartigen Rauchdetektionssystems.

Advantages and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to FIGS. From these show:

• 1 a functional diagram of an embodiment of the smoke detector,
• 2 a realization variant of the voltage stabilizing means in the smoke detector according to 1 .
• 3 a detailed representation of analog and digital assemblies of the smoke detector according to 1 .
• 4 a schematic diagram for explaining an exemplary geometric configuration of essential elements of the smoke detector,
• 5 a further representation, in the manner of a perspective representation, for explaining the geometric configuration,
• 6 a combined representation to further explain the geometric configuration,
• 7A to 7C further illustrations for explaining the mechanical structure of an embodiment of the smoke detector according to the invention,
• 8th a schematic diagram of the geometric configuration of another embodiment,
• 9 a further representation, in the manner of a perspective representation, for explaining this geometric configuration,
• 10 a combined representation for further explanation of the geometric configuration according to 9 .
• 11 a combined representation of one opposite 10 modified embodiment,
• 12 a schematic diagram of the geometric configuration of another embodiment,
• 13 a schematic diagram of the geometric configuration of another embodiment,
• 14 a schematic diagram of the geometric configuration of another embodiment,
• 15 a schematic diagram of the geometric configuration of another embodiment,
• 16 a schematic diagram of the geometric configuration of another embodiment,
• 17 a schematic representation of a multi-part smoke detector as part of a smoke detection system,
• 18 a further schematic representation of a multi-part constructed smoke detector as part of a smoke detection system and
• 19 a schematic diagram of an embodiment of a novel smoke detection system.

1 shows the basic structure of a smoke detector according to the invention SD1.

A power supply voltage Vin is due to the voltage stabilizer STV1 and an energy storage circuit PAC on. The voltage stabilizer STV1 is necessary if we have a power supply from a network where the voltage can change over time. The STV 1 stands with a digital unit YOU in connection. New to this technical solution is that the digital unit YOU the power supply in STV1 and the PAC via an analog-to-digital converter ADC monitor and take over power management.

An important application is eg in 2 shown. The switch-on switching elements KE1 . KE2 . KE 3 . KE4 switch on automatically, and the supply voltage reaches the voltage stabilizer STV and the digital unit YOU , The main switching element KE turns off, causing the analog unit AU is separated. A microprocessor MP in the YOU Now get the power and start the operation. The MP then wait until the storage capacitors C1 and C2 are fully charged, and turns on the switching elements KE1 and KE4 out. So the whole circuit gets only from the storage capacitor C1 a supply that is disconnected from the mains. The MP analyzed over the ADC the am C1 applied voltage, and when it reaches a certain minimum level, the switches MP the switching elements KE2 . KE2 off and then the switching elements KE1 . KE4 on. Now the whole circuit receives only from the storage capacitor C2 a supply.

voltage divider VD 1 and voltage dividers VD 2 use operational amplifiers to split a supply voltage into the operating range of the ADC bring to. The operational amplifiers achieve better energy savings in this case than sharing voltage with a pair of resistors, although one can go that way. The resistors R2 and R4 are the same and they can adequately R1 and R3 differ. This makes it possible to minimize the power consumption from the line and to make the consumption more even without peaks in the supply line. For example, the power consumption is the YOU low if the MP with simple tasks is busy, and the MP can stream out for a pretty long time C1 get and rarely turns on C2 , But then he has to MP perform a smoke density measurement and switch the supply to the freshly charged C2 , then switches the main switching element KE one, so the analog unit AU work, and then the measurement takes place. So in this case is the use of energy from the C2 much stronger than that C1 and has a sufficiently short duration. As a result, there is an even consumption from the external source, and this power consumption is constantly controlled.

The smoke detector can draw its power from a battery and the battery voltage is supplied by the battery MP Constantly measured to alert a user when it reaches its limit. By the analog unit by means of the main switching element KE is turned off, the scored MP a high power saving, and if long-life lithium batteries are used, 5 years of operation can be guaranteed without battery replacement. It is planned to use solar panels for even better power savings and operation without mains connection.

An important aspect is that the digital unit YOU from the analog unit AU can be disconnected so that any high frequency from the microprocessor is not on the supply for the AU and even abrupt switching of MP ports will not result in jumps in the AU supply level. This is in 2 not shown, but the AU can also, managed by the MP in the STV1 , be powered by their own storage capacitors and their own voltage stabilizer. Sometimes it is useful and even necessary to disconnect the digital power supply from the analogue power supply for better results. It has to be said that in the basic modification the power supply for the YOU and AU should come from one source, because this circuit performs well in a normal environment, but in heavy industrial applications this is an important decision. It also helps to protect the device from leaps of current, for example, when someone uses a mobile phone near the utility line or when there are EMI and RFI radiations in an industrial location. Even if a lightning strikes the power line, the device is safe and can be easily repaired.

Furthermore, the microprocessor leads MP a power management on the power storage circuit PAC by. This circuit has storage capacitors and is intended for powering light-emitting elements. It is necessary for the emitting diodes to receive a high current from the current storage circuit for a short time PAC to get. Such a high current may make the voltage in a supply line low and may even exceed the battery resources when powering a device therefrom. That's why power storage and management is so necessary in this case.

The digital unit YOU turns on, then the analog unit switches AU and works for a certain amount of time to get stable results, then he is looking for MP after a suitable time for measurements, and only then the light-emitting elements are switched on while controlling the current level. The switching of light-emitting elements during a short series of pulses is known per se. What is new about the proposed device is that the pulse duration is used to achieve one and the same performance for the measurement circuit in a very broad temperature range.

In order to get a high accuracy in the measurements, one should amplify the signal, and it is much better to use narrow band filters in all amplifiers, so that only pulses with a specifically set duration could pass out of the light emitting elements. This protects the device from EMI noise. The fact that the filters are tuned to a specific frequency makes it possible for their performance to be more responsive to the increase in temperature. In fact, it always happens that filters tuned at + 25 ° C for a certain frequency will not work at that frequency at + 100 ° C (and also at -50 ° C). This is the reason why it is suggested (see below) to calibrate the duration of pulses with temperature and to change the specific frequency of light pulses so that they always pass through the filters and amplifiers throughout the temperature range. The MP does this work by giving data to the power storage circuit PAC and to the current stabilizer STC transfers.

• Man stellt viele Detektoren (15 bis 30 auf einmal) zur Kalibrierung in einen ziemlich großen Raum (nicht wie gewöhnlich in ein Rauchrohr). Es ist wichtig, dass Rauchmelder der offenen Bauart genügend Platz haben, so dass es keine Reflexionen von Licht gibt, das von Wänden abgestrahlt wird (wie in einem Rohr). Dann werden die Detektoren an einen Kommunikationsbus angeschlossen (z.B. eine CAN-Schnittstelle; jede Vorrichtung kann aber auch über einen USB-Bus direkt an einen PC angeschlossen werden, und als Option ist auch eine Ethernet- oder Funkkanalverbindung möglich). Man bringt ein Messinstrument für optische Dichtemessungen in diesen Raum und greift auf seine Daten zu, die auf demselben Computer angezeigt werden. Es wird eine Rauchquelle mit wirklich langsam abbrennendem Material bereitgestellt und der Raum geschlossen. Man erhält konstant Daten über die Rauchdichte von den Detektoren und vom Messinstrument.

It is proposed a current control in the current stabilizer STC To calibrate the sensitivity of the detectors with high precision almost like a fine instrument for optical density measurements. The procedure and procedure for calibration are as follows:

• You put many detectors ( 15 to 30 at once) for calibration in a rather large space (not in a smoke tube as usual). It is important that open-type smoke detectors have enough space so that there are no reflections of light emitted from walls (such as in a pipe). Then the detectors are connected to a communication bus (eg a CAN bus). Interface; Each device can also be connected directly to a USB bus PC and an Ethernet or radio channel connection is possible as an option). You bring an optical density meter into this room and access its data displayed on the same computer. It provides a source of smoke with really slow burning material and closes the room. Constant data on the smoke density is obtained from the detectors and the measuring instrument.

If the smoke density on the instrument reaches a lower threshold (eg, 0.05 db per 1 meter), the system is instructed to transmit that data to the detectors, and they then store that data along with their respective measured density value. At one command, all detectors put their current in the current regulator STC on the DAC2 in the digital unit (drawing 3 ) so that their reading is equal to that of the PC received value is. Since the smoke density increases very slowly, you can get as many points as you like, creating a whole calibration table in the memory of the detectors. When the smoke density reaches its high level (eg, 0.2 dB per 1 meter), calibration is terminated because it is assumed that the detectors will no longer analyze the situation beyond this point. Thus one first obtains a coarse offset value for all the currents in the light-emitting elements and an entire table of correction coefficients for many points. It is important that you first make a rough correction and then find out about fine-tuning points; This allows for good calibration results.

When the source of smoke ceases to burn, open the venting channel and turn on a fan. Experience teaches that the smoke density in this case becomes even more uniform, more gradual, and uniform with equal distribution over the entire volume. One again records data from the measuring instrument, compares it with the data of already calibrated detectors and, if necessary, makes small adjustments.

Another important point is that the level of current flowing through the LEDs can vary significantly with temperature. Actually, light-emitting diodes have very good stability and a temperature-induced change in their light intensity can be disregarded. But analog components in the current control circuit can change their characteristics. For example, if you have one FED used to open the flow of current through light-emitting elements, its response to a certain level of the DAC2 change sufficiently due to temperature, even if the DAC2 the same level in its performance (but its level will change even at high temperature). That is why data obtained under normal conditions should be checked and updated for the entire temperature range. This can be done in a temperature chamber using only 2 Smoke densities (or even without smoke) take place. In practice, the detectors can be placed in a temperature chamber (without smoke) and the data on the current in the STC from the ADC compare with data sent to the DAC2 were transferred to this stream in the STC to achieve. One takes corrections to the DAC2 Data, so that it is one and the same stream, by the ADC measured over a wide temperature range (from -50 ° C to + 55 ° C); Points for higher temperatures are calculated by approximation. Results for some real smoke densities can also be demonstrated for this temperature range, but they are quite similar if correction is taken into account in smoke-free conditions.

With this approach, you get a very thoroughly calibrated smoke detector with temperature compensation that accurately measures a smoke density just like a very expensive instrumental device. What is good and new is that no other smoke detectors of the open type on the market can measure the smoke density in concrete numbers, they all give only alarm levels. Most open-type detectors only gain an approximate knowledge of the smoke density in an uncertain volume.

In 1 you realize that a digital thermometer unit TU contained in the device. It is primarily intended for calibration and temperature compensation during use. However, they can also be used as temperature detectors of the maximum / differential type for better fire detection.

First, let's take a look at the detailed functional scheme in 3 thrown. It should be together with 4 to be viewed as.

First shows 4 a group EE1 of light-emitting elements arranged on a hyperbola. There are deliberately used at least 3 light-emitting diodes, which are located at some distance from each other. This results in a better spatial distribution of the light emitted in space in the detection area from slightly different angles. When light reaches a smoke particle, it is more likely that the light will fall on a flat reflective surface of a smoke particle. If you only use a light-emitting diode, runs the light from it at angles of ± 5 ° to the detection area, but each smoke particle in the area receives light from only one direction, the line connecting this particle and the emitting diode. Using 3 diodes, each particle receives light from 3 slightly different directions. This gives a higher probability that light will strike a reflective edge of the smoke particle. Of course, there may also be more than 3 light emitting diodes, and the sensitivity of our device will increase in proportion to the number of light emitting elements. For example, in highly sensitive applications, using a fiber optic cable to transmit light to a high temperature zone and receive signals using the fiber optic cable is very helpful.

It is important to use conventional LEDs rather than laser diodes in general-purpose applications to ensure eye protection. Since light is emitted into the open space, it can reach a person's eyes, and this is particularly dangerous with laser diodes, e.g. when a child stares at the detector in service. For this reason, the proposed smoke detector combines light from several universal diodes only in a very narrow area, about 20 cm from the ceiling. Outside this zone, the light from the three diodes splits into three different beams, loses energy rapidly as distance increases, and is not dangerous to the eyes.

The light-emitting diodes EE1 the group 1 in 4 are on a hyperbola. Namely, because the light from all the diodes at the same angle to the optical axis of the sensor element SE1 should steer. The standard recommended angle is 110 °. Thus, if one inserts a tip of an imaginary cone (at an angle of 110 ° from the axis to the side) into the detection range and points it with its axis SE1 It will be seen that the points of intersection of this cone with the plane surface of the detector produce a hyperbola ( 5 ). If, in another partial modification of the device (see 8th ) chooses a sufficiently smaller angle, eg 70 °, then the intersections will give a helical line.

It should be noted that the light emitting elements may be a composite (not just diodes), ie, diodes may be used in conjunction with a lens or optical prism or other optics. In some applications, one uses an optical fiber, in other applications a special plastic prism that makes the surface of the emissive element flat and level with the surface of the detector. In simple applications, the emitting element is just a diode with its own lens inserted into a narrow channel in the housing (the same solutions apply to the sensor elements). The sensor elements of the group SE1 may also be arranged (as a group) on a curve. This can help to avoid obstacles such as flying insects or flies sitting on the diodes. However, the basic version has only one photodiode SE1 ,

In the block of light-emitting elements in the functional diagram in 3 you have a light-emitting element TEA included for test purposes (see 4 ). The light-emitting element for test purposes is necessary because if there is no smoke in the detection area, no response and no optical signal are returned. That's why the photodiode is being tested to see if it works properly and just can not be detected in the area. This diode TEA is only used to prove that the photodiode in the sensor element SE1 is active. The light-emitting element for test purposes can be arranged not only on the surface of the detector but also in it, in which case light in the rear part of the sensor element SE1 is transmitted. There is no need for the light emitting elements to test emitted light because one can measure the current flowing through these diodes, and where there is power there is also light.

Furthermore one recognizes in 4 sensor elements SE1 and SE2 , The main sensor element is SE1 , it receives light from the detection area and we make measurements based on signals from SE1 , The sensor element SE2 is directed away from the detection area, it does not receive signals from the light-emitting elements EE1 , Its optical axis is in one and the same direction but at a certain distance from each other (see 6 ) is at substantially the same angle with the surface of the detector as the optical axis of the detector SE1 , The task of the sensor element SE2 is to protect the device from sunlight and artificial light. When sunlight falls on the detector, both receive that SE1 as well as SE2 this signal because sunlight is always a parallel beam of light.

In the functional schema ( 3 ) you can see that signals from the light sensing elements SE1 and SE2 by separating capacitors SC1 and SC2 go through and then to a summator S1 go. The isolation capacitors are intended to provide a constant offset of transducers CVC1 and CVC2 to exclude, and also to exclude constant background light. Here, a large part of the sun's energy is already excluded. Then in the summator S1 Signals from SE1 and SE2 subtracted because that SE2 at the input of the summing element S1 is inverted. This solution helps to eliminate the rest of sunlight and achieve a perfect balance against natural and artificial light sources. This is important because sunlight in practice undergoes modulation from the atmosphere, and simply disconnecting a constant level with a cut-off capacitor does not always provide relief. Even though there is a nearby lamp, there are vibration-modulating light modulations. With the proposed solution this is completely excluded.

In 3 it can be seen that each light detection element is connected to its own current / voltage converter ( CVC1 and CVC2 ) connected. This is new because photodiodes are used in short circuit mode CVC1 the tension in the SE1 keeps close to zero, and SE2 generates a current signal in response to light. Then he walks CVC1 Signal current in signal voltage to. Because of this solution, the device can never be dazzled by a high intensity signal. Usually, a photodiode saturates when it receives high intensity light and can not work for a long period of time.

The operation of the summing element S1 in 3 is managed by the microprocessor. A signal from the summing element S1 go to the amplifier A1 , then to ACD and finally in digital form to the microprocessor MP , This solution helps to balance dust and achieve absolute immunity to all types of artificial light sources, be it incandescent, Hg, halogen or new energy-saving bulbs or even power diode light solutions.

• Der Mikroprozessor MP schaltet im Summierglied S1 beide Kanäle (vom SE1 und SE2) ein und erhält dann verstärkte und digitalisierte Signale, die für den Unterschied zwischen SE1 und SE2 stehen. Handelt es sich um eine schwache Quelle künstlichen Lichts oder befindet sich diese Quelle in einem erheblichen Abstand, werden die Signale vom SE1 und SE2 gleich sein und der MP erhält ein Signal nahe Null. Dann ist es sicher, Messungen durchzuführen.

The method of suppressing interference from artificial light sources includes:

• The microprocessor MP switches in the summing element S1 both channels (from SE1 and SE2 ) and then receives amplified and digitized signals representing the difference between SE1 and SE2 stand. If it is a weak source of artificial light or is this source at a considerable distance, the signals from the SE1 and SE2 be the same and the MP receives a signal near zero. Then it is safe to take measurements.

But if the source of artificial light is strong or so unfavorably arranged that direct light on the SE1 but almost no light on that SE2 falls (for example due to a lampshade or sunroof edge or any other edge of equipment), sufficient signals will be output at the amplifier A1 issue. The microprocessor MP observes this situation, recognizes the waves of modulated light from artificial sources, because all lamps get their power at the industrial frequency of 50 Hz or 60 Hz. With emitted light, this frequency is doubled to 100 Hz and 120 Hz, respectively, because the lamps emit light in both positive and negative half cycles. The microprocessor MP finds the time interval in which the signal from the lamps reaches its minimum value, and in this minimum, real measurements of smoke density are made. This method even eliminates such a dangerous source as a Hg 500W searchlight at a distance of 0.5 m. This particular lamp is very critical because it has a broad spectral characteristic and passes through all the optical filters.

• Der Mikroprozessor MP erhält eine Betriebsspannung aus dem Spannungskonstanthalter STV1 und beginnt mit der Arbeit. Der Mikroprozessor MP schickt eine Messungsanforderung an den ADC und erhält Daten über die Spannungspegel der Speicherkondensatoren im STV1 und der Stromspeicherschaltung PAC zurück. Wenn alle Kondensatoren voll geladen sind, ist der Betrieb der analogen Einheit AU möglich. Danach erfüllt der Mikroprozessor MP konstant die Stromversorgungsverwaltung, wie zuvor beschrieben wurde. Gleichzeitig misst der Mikroprozessor MP konstant die Umgebungstemperatur mit Hilfe der digitalen Thermometereinheit TU. Der Mikroprozessor MP schaltet das Schaltelement KE ein und wartet einen vorbestimmten Zeitraum lang, bis die analoge Einheit AU in einen stabilen Betrieb gelangt. Der Mikroprozessor MP schaltet beide Kanäle im Summierglied S1 ein und empfängt über den ADC ein Signal vom Verstärker A1, um den Zeitpunkt zur richtigen Messung mit minimalem optischen Rauschen zu bestimmen, wie oben im Verfahren zur Bekämpfung künstlicher Lichtquellen beschrieben wurde.

The main method of measuring smoke density involves the following steps:

• The microprocessor MP receives an operating voltage from the voltage stabilizer STV1 and starts work. The microprocessor MP sends a measurement request to the ADC and receives data about the voltage levels of the storage capacitors in the STV1 and the power storage circuit PAC back. When all capacitors are fully charged, the operation of the analog unit AU possible. Afterwards the microprocessor fulfills MP constant power management as previously described. At the same time the microprocessor measures MP constant ambient temperature with the help of the digital thermometer unit TU , The microprocessor MP switches the switching element KE and wait for a predetermined period of time until the analog unit AU gets into stable operation. The microprocessor MP switches both channels in the summing element S1 and receives over the ADC a signal from the amplifier A1 to determine the time for the correct measurement with minimal optical noise, as described above in the method for combating artificial light sources.

If the signal from the amplifier A1 reaches its minimum, the microprocessor turns off MP a freshly charged storage capacitor C2 in voltage stabilizer STV1 on (and turns off the C1 the AU out, causing the C1 connected to input voltage). In simpler modifications, the microprocessor monitors MP just the voltage at STV1 so the analog unit AU gets the necessary voltage, and if the stabilized voltage on the analog unit AU from a predetermined value, the microprocessor calculates MP this difference and make corrections to received signals. If the microprocessor MP has determined the right time to take measurements he data about the current level to the DAC2 which should be made via the light-emitting elements with respect to the ambient temperature. The digital / analog converter DAC2 sets its output according to this data, and this signal goes to the power stabilizer STC , Then the microprocessor turns off MP the current stabilizer STC and this sends measuring current to the light-emitting elements (group EE1 in 4 ). Light from the light-emitting elements extends at one and the same angle to the optical axis of the main sensor element SE1 ( 5 ) through the detection area. Preferably, but not exclusively, the angle is 110 °.

First, consider a situation where there is no smoke in the area. Depending on the STC generated signal, send the light-emitting elements (group 1 ) a very short pulse of light (or a series of pulses) of known duration and intensity characteristic controlled by the microprocessor MP , The light signal reaches the detection area, but there is no smoke and so no light can be scattered by smoke particles. However, obstacles may be in the area, such as nearby walls or rows of containers in warehouses and the like. Like., or hands of cleaning personnel near the detector and on this sitting insects. Thus, even without smoke, a certain signal from the light-emitting elements can be reflected back from the detection area, and this light reaches the sensor element SE1 , Then this light gets through the SE1 converted into an electrical current signal that the current / voltage converter CVC1 then converted into a voltage signal. Then only the AC part of this signal passes through the isolating capacitor SC1 , The same conversion is done by the SE2 , the CVC2 and the SC2 , Both channels meet in the summing element S1 each other.

If backlight sources are present, the light signal from them reaches both sensor elements SE1 and SE2 and is in the summator S1 effectively subtracted. Then only high-frequency pulses (over 1 kHz) pass through the isolating capacitor SC3 to protect the measuring part from industrial EMI radiation (with frequencies of approx. 50 - 60 Hz or 100 - 120 Hz). Short duration pulses from the light emitting elements, which are reflected by obstacles in the area, then pass through the cutoff capacitor SC3 and reach the summer S2 , The microprocessor MP sends a zero value to the DAC1 so that the signal from the SC3 unchanged to the output of the summing element S2 goes. The microprocessor MP sends a command to the ADC To take measurements and receives data via signals at the output of the summer S2 back. If there is a very strong reflection (for example, of nearby walls or if one protects a ventilation duct or a narrow channel for electric cables), then the microprocessor already receives a significant signal at this stage. So sends the microprocessor MP a calculated value to the DAC1 , and the DAC1 Balances the noise measured from reflections in the detection area.

Then a new measurement takes place, this time the microprocessor MP the level in DAC1 advance to the previously calculated value, so that the signal from the DAC1 from the signal from the separator capacitor SC3 is subtracted. Since the signals are almost completely balanced, you now need a gain to see a certain significant signal. That's why the microprocessor MP from the ADC also signals from the output of amplifiers A2 . A3 and A4 each of these having a certain gain, preferably with steps of x10 (each signal is tied to 10 amplified) at each amplifier. Thereafter, this microprocessor MP corrects data for the DAC1 and will continue to use this more accurate value. The most accurate measurement of a noise signal from reflection occurs when the DAC1 No smaller numbers to perform a fine correction and almost the entire noise is balanced. Then the microprocessor MP measures with the help of the ADC a signal from an integrator Int that receives the signal from the A4 while integrating pulses. The result provides an offset value for the finest correction, and this data, along with correction data for the DAC1 stored in the MP (eg in a ROM or flash memory). The microprocessor MP continues to take measurements at certain intervals, eg 1 time in 1 second.

When smoke appears in the detection area, light from the light-emitting elements in the detection area hits smoke particles, some light becomes the sensor element DE1 reflected, and no light is from smoke particles to the sensor element SE2 reflected ( 6 ). The microprocessor MP determines the duration of short pulses of light (or rows of pulses) in terms of temperature, so that the pulses are at the operating frequency of narrow band filters in the amplifiers A2 . A3 and A4 fit (as described in the calibration procedure above). Usually, this duration will be on the order of 15 microseconds under normal conditions. The microprocessor MP also determines the light intensity, sends data to the DAC2 and represents the known current in the current stabilizer STC her (to the DAC2 sent data depends on the temperature value, as described above).

The microprocessor MP regulates the real current through the light-emitting elements Help of the ADC , When a light signal from the detection area is scattered by smoke particles, it reaches the sensor element SE1 and is converted there into an electrical current signal. Then it converts the current / voltage converter CVC1 into a voltage signal. Only the AC voltage part of this signal passes through the isolating capacitor SC1 , The same conversion is done by the SE2 , the CVC2 . SC2 only on the noise signal.

A light signal from backlight sources reaches both sensor elements SE1 and SE2 and is in the summator S1 subtracted. Short-duration pulses from the light-emitting elements pass through the separating capacitor SC3 and reach the summer S2 , The microprocessor MP sends a previously calculated value to correct a noise signal from reflections to the DAC1 , In the summator S2 the signals are subtracted, and then only the real part of this signal, which corresponds to the real signal of smoke, goes to the amplifiers A2 . A3 A4 and the integrator int through. The microprocessor MP layer a measurement request to the ADC and receives all these signals in digital form. Then the microprocessor takes into account MP the measurement signal level, subtracts the offset value from the noise, compares the result with the coefficient table stored in its memory (according to factory calibration section 3 ), and calculates the real smoke density value. Then he compares MP this value with predetermined threshold values, and if the measured value is greater than a first threshold, generates the MP a signal "attention". If this value has risen to a second threshold during a predetermined time (as recommended by regulations), then MP a signal "alarm".

There may also be other fire protection policies, for example, a user may choose to only cross a threshold without time calculation. Or the user may determine that the smoke intensity is differentiated and an alarm is given in case of a sudden signal increase. Or the user may choose to ignore sudden jumps (because of the proximity of the person being moved by the detector), but in this case the detector may perform a series of quick successive measurements effectively eliminating reflections from moving objects. For other applications, a quick response even to low smoke levels is essential (for example, ventilation systems extract almost the entire volume of air and fill rooms with fresh air for 1 minute).

The microprocessor MP can transmit with the help of an output driver always accurate data on the smoke density to the higher level of the fire protection system. And this is also highly recommended because at the higher level, the receiving unit collects information about smoke density levels from many different detectors and performs statistical analysis, separating numbers that may give rise to suspicion (for example, if there is real smoke near a detector) small source such as a cigarette is detected, but at other detectors only a slow increase in the background noise level can be seen). This is accomplished in one of our many detector unit modifications. That's almost all about the main process.

The procedure for dust compensation in the detector includes special design solutions that are available in 7 are shown. The inventors have found that when a groove is made on the circumference of the detector housing to pass through the light emitting elements and sensor elements, reflections of light passing through the reflective edges of the groove from the light emitting elements to the sensor elements are seen even if there is no direct passage of light. It does not matter how big or thin this groove is, it should only pass through the elements with the light emitting and sensing elements located on its inside. So there are several design solutions for dust compensation.

In a first solution, you milled a broad oval plane and leave a smooth edge on the circumference in the form of a helix, and in the middle of the housing in the form of a flat circle. The second design solution has two separate grooves of oval shape, one containing light-emitting elements and the main sensor element SE1 and the second, smaller oval groove includes light emitting element and the second sensor element SE2 , A third design solution has only small reflective surfaces near the light-emitting elements and the second sensor element. The small reflective edges in this solution are actually just a continuation of channels in the detector housing into which light-emitting elements are inserted; this is sufficient to provide sufficient reflection to the sensor element SE1 to obtain. All protruding parts are in 7 marked hatched.

In the proposed method of dust compensation, the microprocessor measures MP first the signal from the main sensor element SE1 , To do this, the microprocessor selects MP a possible time for measurement according to the method for combating artificial light, then measures the signal from the detection area after the main process, and then corrects this. A dust correction is only carried out if there is no risk of fire. Then the MP transmits a signal to the summer S1 and switches the channel off the sensor element SE2 off to only take measurements at SE1 perform. The MP measures the signal from SE1 and stores it in its memory, then sends a signal to the summer S1 and switches the channel off the sensor element SE1 off and on from the sensor element SE2 one to only on SE2 Perform measurements. Then he measures MP the signal from SE2 and also stores it in its memory. The MP compares signals from a previous calibration with newly measured signals and calculates a saturation of the signal due to dust on its surface.

Thanks to this process, you know exactly what numbers the detector was measuring when it was first installed and what numbers it has after years of operation. Signals are also measured precisely at the working diodes SE1 and SE2 with real light-emitting elements used for measurements in the main process. This prevents errors due to different dust thicknesses or obstacles on diodes. It is also important to note that in this case no test light emitting element is needed because one always has a signal from the reflective groove to test the device.

In various figures, there are various design variants: Smoke detectors of the open design (variant 1, 4 ), Smoke detectors of the open design combined with temperature detector (maximum / differential design) (variant 2, 13 ), Smoke detectors of open design, combined with UV flame detector (variant 3, 14 ), Smoke detector of open design, combined with IR flame detector (sensitive in at least 2 spectral ranges) (variant 4, 14 ), Smoke detector of open design, combined with temperature detector and UV flame detector (variant 5, 15 ), Smoke detector of open design, combined with temperature detector and IR flame detector (variant 6, 15 ). Smoke detector of open design, combined with temperature detector, UV flame detector and IR flame detector (sensitive in at least two spectral ranges) (variant 7, 16 ).

There may also be partial modifications combined with temperature detectors and flame detectors of the UV and / or IR type. All of these variants can be equipped with optical fibers or cables to provide communication between the control unit MU (where the entire electronics are located) and a remote detector unit RDU (where you only optics for high-temperature applications or uses reliable simple electronics such as diodes) (variant 10, 17 ). A modified solution is variant 11 in 18 shown. 18 shows a main detector unit MU, with several remote sensor units RDU1 to RDU4 connected is. This is a good solution for the industry, where a large work hall or workshop can be protected as a zone for a fire extinguishing system. This gives users the opportunity to install only one or two detectors with many remote sensor units (up to 30 on a main unit) instead of dozens of separate detectors. This is an exceptionally economical solution.

• Aus 3 ist ersichtlich, dass der Mikroprozessor MP Feineinstellungen in den Verstärkern A2, A3 und A4 durchführen kann; dies wird zur automatischen Kalibrierung der Vorrichtung im Werk benötigt. Die Verbindung zwischen dem MP und dem Integrierglied ist dazu gedacht, das Integrierglied nur in bekannten Zeiträumen mit Speicherung des Pegels des integrierten Signals und seiner Rücksetzung durch den MP arbeiten zu lassen. Es wird gegenwärtig ein Hochgeschwindigkeits-ADC verwendet, in preisgünstigeren Modifizierungen kann man aber einen langsameren ADC in Kombination mit einem durch den Mikroprozessor MP gesteuerten Spitzendetektor verwenden. Der ADC kann ein Teil des Mikroprozessors sein.

In the following some mentionable aspects of advantageous embodiments of the proposed smoke detector or its operation and its application are mentioned:

• Out 3 it can be seen that the microprocessor MP Fine adjustments in the amplifiers A2 . A3 and A4 can perform; this is needed to automatically calibrate the device in the factory. The connection between the MP and the integrator is intended to enable the integrator only in known time periods with storage of the level of the integrated signal and its reset by the MP to work. There is currently a high-speed ADC used in cheaper modifications, but you can use a slower ADC in combination with one through the microprocessor MP use controlled peak detector. The ADC can be part of the microprocessor.

The typically weak signal of the light sensing element generally requires high gain factors, but these are inevitably associated with corresponding power consumption and additional noise. In an embodiment of the evaluation circuit, therefore, a primary signal consisting of a positive and subsequent negative half-wave, after filtering and amplification, is processed by inverting the negative half-wave and adding to the positive half-wave. In an embodiment in which suitable switching elements are provided in front of the integrator, parts of the half-waves are masked out in order in particular to pass only the middle section with the greatest signal amplitude as the useful signal.

Practical designs have a metal body, are shockproof and vandal resistant, have a socket with screws, no flush solution, but a solid attachment of wires to contacts on the side surface of the socket with screws. This solution is resistant to all types of vibration and can be safely used even in railway wagons.

There may be several groups of light-emitting elements, which gives a better performance in black smoke (see. 8th . 9 . 10 ). Two different zones can be set up for earlier detection, and for smoke spreading in layers or horizons (cf. 11 ). There may be groups of light-emitting elements with different spectral sensitivity, this allows us to distinguish black smoke and aerosols from burning metals (such as Na, Al, Fe) (cf. 12 ). The open-type smoke detector can be combined with a temperature detector, flame, UV and IR detector (cf. 13 . 14 . 15 . 16 ).

One aspect of the present invention is also in the oppose of constructing a novel smoke detection system as disclosed in US Pat 19 is shown sketchy. The smoke detection system SYS includes in the exemplary illustration a system control station SCS and three smoke detectors SD1 . SD2 and SD3 with fundamentally different structure, which are arranged in different rooms of a building to be monitored. The smoke detector SD1 is of the integrated type, where all components are housed in a single housing; the smoke detector RD2 is of the two-part type, as in 17 and 19 shown and described above, and includes a control unit MU2 and a remote detector unit RDU2 and the smoke detector RD3 can be referred to as a multi-part type, in which next to a control unit MU3 and a detector unit which contains the transmission and detection elements serving the actual smoke message RDU3 still (at least) a remote additional detector XDU is provided. Connections between the system components and subcomponents are made in the manner described in the general part of the description as a first, second, and third level bidirectional communication link, at least in part, on an optical fiber basis.

One method of operating such a network is as follows: There is a special program on a laptop or receiver unit with radio channel, and this program finds a detector from our company as soon as it is turned on. Then the detectors are switched on one at a time and attached to the ceiling according to the project documentation, and no wire connection is needed. The detectors register themselves in the PC, and they get access rights depending on their priority. So you first install "server" messages that forward information from other subordinate detectors to the PC, and the "server" messages must always be in direct view of each other. If a "server" detector is separated from others by a wall, it may be necessary to make a short wire connection through the wall to the nearest detector. In practice, these wire connections are very short (about 2 m) and can be mounted through the door entrance. Subordinate detectors in each room transmit their information to the "server" detectors, which then pass them through each other to the main PC or just a receiver unit with radio channel. This means that a detector network can be set up in a school without difficulty, without wire connections and costs for its assembly and with considerable savings in hardware.

The embodiment of the invention is not limited to the examples shown and described herein and the aspects highlighted, but also in a variety of modifications are possible, which are within the scope of technical action.

Claims (6)

A method of making an open type smoke detector having at least one light emitting element and at least one light sensing element in an open housing and a power supply unit and a control unit, the method comprising a calibration procedure comprising the steps of: a) providing and operating the smoke detector in FIG a large room, together with a calibrated smoke density meter and in conjunction with a calibration control unit via a bidirectional communication channel and optionally to the calibrated smoke density meter; b) Gradually filling the room with smoke; c) in response to detection of a first predetermined value of smoke density by the calibrated smoke density meter, instructing the smoke detector to store its own current detection signal or to transmit it to the calibration control unit and instruct the calibrated smoke density meter to transmit its signal a n) the smoke detector or the calibration control unit, d) performing a comparison between the detection signals of the smoke detector and the calibrated smoke density meter, and processor-based adjustment of the current in a current stabilizer of the power supply unit of the smoke detector such that its detection signal is made equal to the detection signal of the calibrated smoke density meter to obtain a first calibrated measuring point of the smoke detector, and storing the corresponding adjusted current value, and e) providing a calibrated operation of the smoke detector using the stored calibration table, characterized by f) repeating steps c) and d) a predetermined number of times Painting with increasing smoke density in the room, to obtain further calibrated measuring points and corresponding current values of the smoke detector and thus a calibration table and to store in a memory of the smoke detector, and include and obtaining corresponding smoke detector signals at at least two different temperatures in a vanishing or constant smoke density atmosphere Comparing the smoke detector signals, adjusting the power supply so that the smoke detector signals become the same at the different temperatures, storing the respective T-adjusted current values in relation to the different temperatures, and providing a T-calibrated operation using the stored T- adjusted current values. Method according to Claim 1 comprising the further steps of: g) starting the operation of the smoke detector in the first calibrated operation, h) gradually removing the smoke from the room, i) repeating steps c) and d) a predetermined number of times during the gradual reduction of the smoke density to obtain and store a refined calibration table; and j) provide a second calibrated operation of the smoke detector using the stored refined current values. Method according to Claim 1 or 2 wherein step b) is carried out by burning a sample in the room. Method according to Claim 2 or 3 wherein the step h) is carried out by operating a suction device, in particular after the burning of the sample is completed. A method of manufacturing an open type smoke detector having at least one light emitting element and at least one light sensing element in an open housing and a power supply unit and a control unit, the method implementing a calibrated operation using stored sets instead of a detector specific calibration procedure of current values determined by a method according to one of the preceding claims for at least one other smoke detector. Method according to Claim 5 which includes a replacement calibration procedure using a smoke density equivalent.

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