Extractive smoke detector, method of operation thereof, and computer program product

Abstract

The invention relates to a method for operating an extractive smoke detector, an extractive smoke detector corresponding thereto and a computer program product. Ambient air is extracted by means of a suction unit via a suction duct provided with a suction opening and fed to a fire detector unit for determining a signal level. For normal operation, the suction power is set to a nominal airflow value and this value is increased from a minimum signal level value in order to shorten the transmission time of the extracted smoke through the suction duct to the fire detector unit. According to the invention, if the airflow exceeds an upper limit value for a minimum period of time, an interruption signal provided for normal operation is output, in particular according to standard EN 54‑20: 2009‑02 or UL268, 6th or 7th edition. Independently of this, the suction power is increased from the minimum signal level value only to the extent that the airflow does not exceed the upper limit value. Or, in any case, the suction power is increased only within a time span that is smaller than the minimum period of time in which the airflow exceeds the upper limit value.

Description

[0001] The invention relates to a method for operating an extractive smoke detector, an extractive smoke detector of this type and a computer program product for carrying out the operating method according to the invention. Extractive smoke detectors or fire detectors of this type are referred to in technical terminology as extractive smoke detectors (ASD).

[0002] In the method, an extractive smoke detector is provided for detecting a fire in a monitored space and for outputting a fire alarm in the event of a fire being detected, typically to a fire alarm control panel (FACP). In this context, ambient air is extracted via a suction duct of the extractive smoke detector by means of a suction unit of the extractive smoke detector, the extractive smoke detector being provided with a suction opening for smoke or combustion gases to be detected, and a fire detector unit of the extractive smoke detector for determining a signal level of a fire characteristic by measuring. The suction power of the suction unit for generating an airflow through the suction duct is set to a nominal airflow value for normal operation, i.e. to a nominal airflow value provided for normal operation. Finally, the suction power is increased from a minimum signal level value of the signal level in order to shorten the transmission time of the extracted ambient air with smoke and / or combustion gases through the suction duct to the fire detector unit.

[0003] The extractive smoke detector considered herein comprises at least one fire detector unit for determining by measurement a signal level of a fire characteristic, a suction unit, a power control unit for setting the suction power of the suction unit and a suction duct connected to the suction unit, the suction duct having a suction opening for extracting ambient air with smoke and / or combustion gases to be detected. Furthermore, the extractive smoke detector comprises an airflow meter, in particular a volumetric flow meter, for acquiring the airflow of the extracted ambient air, and an electronic control unit connected to the fire detector unit, the airflow meter and the power control unit. The electronic control unit is configured to adjust the suction power of the suction unit to a nominal airflow value for normal operation by means of the power control unit, to increase the suction power from a minimum signal level by means of the power control unit to shorten the transmission time, and to output a fire alarm in the event of a detected fire. The suction unit and the fire detector unit typically form a modular unit.

[0004] A method of this type and an extraction smoke detector of this type are known from patent application EP 2 244 236 A1. By increasing the fan speed and thus the suction power, the transmission time of the extracted ambient air with smoke through the suction duct to the fire detector unit is shortened. As a result, faster fire detection is possible.

[0005] From EP 2 407 946 A1 of the applicant, a method for detecting blockages and interruptions in a pipe system and a corresponding extraction smoke detector are known. Air is extracted from the room or installation to be monitored via the pipe system by means of a fan and monitored for fire characteristics. The airflow and the air temperature of at least a portion of the extracted air are measured. If the airflow falls below a predetermined lower limit value, a blockage signal is output, and / or if the airflow exceeds a predetermined upper limit value, an interruption notification is output. The speed of the fan increases with increasing air temperature and decreases with decreasing air temperature.

[0006] "Airflow" means the volume flow rate of air or air mass flow rate Therefore, it is a time-dependent physical variable. Air volume flow rate and air mass flow rate According to the physical relationship are linked to each other via density ρ.

[0007] "Normal operation" means normal operation without fire or smoke. For example, it exists after commissioning or repair of an extractor smoke detector.

[0008] "Suction duct" generally means a duct system or hose system. For example, the suction duct may comprise a single duct, preferably made of plastic material, or may comprise a plurality of branch ducts (partial pipes), which are separated by means of a duct distributor. The suction duct generally has a circular cross section, with a diameter in the range of 1 cm to 5 cm, preferably in the range of 2 cm to 3 cm. In particular, the suction duct has a minimum duct length of 30 m, preferably 50 m. A plurality of suction openings are present or introduced along the suction duct. They may exist at equal spacings along the suction duct, for example, at spacings of 4 m to 8 m.

[0009] The signal level of the fire characteristic to be determined by measurement is usually the concentration level or concentration value of the detected smoke or detected combustion gas as a possible fire characteristic. Smoke contains particles of different sizes, which are also called smoke suspended particles. Typical combustion gases are, for example, carbon monoxide or ammonia. The fire detector unit can have an optical detector unit according to, for example, the scattered light principle or the transmitted light principle, or a gas sensor sensitive to combustion gases, such as a CO gas sensor. In particular, the minimum signal level is rated so that there is a sufficiently high probability for a possible fire event, i.e. it is significant for a possible fire event. The setting of the minimum signal level can be based on empirical values ​​from similar fire monitoring environments, or can occur by measurement technology with field fire tests.

[0010] The signal level of the fire characteristic to be determined by the measurement is usually a concentration level or a concentration value of the detected smoke or detected combustion gases as a possible fire characteristic. In particular, the minimum signal level is rated so that there is a sufficiently high probability for a possible fire event, i.e. it is significant for a possible fire event. The suction unit, usually a fan, and the fire detector unit are usually but not necessarily accommodated in a common housing as a modular unit. Seen in the flow direction, the suction unit of the fire detector unit can be connected upstream or downstream. The fire detector unit can have an optical detector unit according to the scattered light principle or the transmitted light principle and / or can have a gas sensor unit for combustion gases.

[0011] Extraction smoke detectors usually have a fan (extractor). It draws an air sample from the space via a suction duct and directs it to the fire detector unit. The suction duct can extend over hundreds of meters. Therefore, the extracted air is tested over the entire length up to the fire detector unit. The time required for this is also called dead time or transmission time. For long suction ducts, the transmission time can be in the range of several minutes. Therefore, for a 200m long duct with a mean flow velocity of 1m / s and a smoke extraction at the end of the duct far from the fire detector unit, the maximum transmission time can be 200 seconds.

[0012] Typically, the "ASD Planner" calculates basic parameters so that the extractive smoke detector thus meets the relevant standards, for example, the standard EN 54-20 applicable in Europe in the version relevant at the time of the present patent application in February 2009, or the standard UL268 applicable in North America, preferably from the 6th or 7th publication. Different parameters play a role in this, such as the pipe length, the size of the space, the number of suction openings, the suction pressure and the sensitivity of the fire detector unit. For the technical design of extractive smoke detectors, different software-supported development tools are known, such as, for example, the ASYST development tool from Siemens. Once the parameters have been determined, the suction pipe is assembled by a technician, the suction openings in the form of holes are drilled into the suction pipe, and the fire detector unit is configured according to the specifications.

[0013] Typically, the suction power of the fan is adjusted via a set speed so as to set an airflow with a nominal airflow value through the suction duct. This speed is then kept constant during normal operation without smoke and / or fire over the life of the detector. In this normal operation, the extractive smoke detector is therefore parameterized with a low fan speed in order to extend its life and minimize the noise level during extraction. The reason for the statistical adjustment is that during the operating time of the extractive smoke detector, an interruption is detected with an increase in the associated airflow, or a blockage of the suction opening by dust is detected with a decrease in the associated airflow. For example, according to the aforementioned EN 54-20, once the airflow deviates from the nominal airflow value by ±20%, the extractive smoke detector is to output a fault within the 300 seconds specified in the standard. In the standard UL268, preferably from the 6th or 7th edition, 90 seconds are applied instead of the aforementioned 300 seconds. The nominal airflow value measured in liters per second or liters per minute is usually set during the commissioning of the extractive smoke detector.

[0014] Starting from EP 2 407 946 A1 mentioned in the introduction, it is an object of the present invention to provide an improved method for operating an extractor smoke detector.

[0015] A further object of the present invention is to provide a more reliable method for operating an extractive smoke detector.

[0016] It is a further object of the present invention to provide an improved extractor smoke detector.Finally, it is an object of the present invention to provide an extractor smoke detector which functions more reliably in operation.

[0017] The objects of the invention are achieved with the subject-matter of the independent claims. Advantageous method variants and embodiments of the invention are disclosed in the dependent claims.

[0018] According to the present invention, in normal operation without fire or smoke, when the airflow exceeds the upper limit value for a minimum period, an interruption signal is output, wherein the suction power is increased from the minimum signal level, i.e. exceeds the minimum signal level, in particular only shortens the transfer time to the extent that the airflow does not exceed the upper limit value, or the suction power is increased from the minimum signal level, i.e. exceeds the minimum signal level, in particular only shortens the transfer time within a shorter time span than the minimum period in which the airflow exceeds the upper limit value.

[0019] In other words, in the latter case, the suction power is increased only for a minimum period to shorten the transfer time so that the airflow exceeds the upper limit value.

[0020] By means of a targeted increase in the power- and possibly time-limited extraction capacity, it is advantageously possible to prevent the output of false interruption signals in addition to a faster possible fire detection. This prevents maintenance specialists from making unnecessary checks of the extractive smoke detector. However, the method according to the invention does not impair the monitoring of the extractive smoke detector, which, as specified in the standards mentioned in the introduction, operates independently of the fire detection, for interruptions and for blockages.

[0021] In a first version of the method according to the invention, if the suction power is increased only to such an extent that the airflow does not exceed or only does not exceed the nominal airflow value, this increase is in principle unlimited in time. In practice, however, regardless of whether a fire event is detected or not, the suction power is preferably reduced again no later than the expiration of a predetermined waiting time, for example after 10, 20 or 30 minutes, so that the airflow reaches the nominal airflow value again.

[0022] With the return to normal operation, the noise development caused by the increased extraction power and the mechanical, life-reducing overload of the extractive smoke detector caused by the increase subsides again.

[0023] In a second embodiment of the method according to the invention, if the suction power increases so that the airflow exceeds the nominal airflow value, for example by 1.2 to 5 times, preferably by 2 to 3 times, then no interrupt signal is output if the increase is limited in time to a minimum period from the point in time when the upper limit value is exceeded.

[0024] In other words, before the end of the minimum period is reached, in particular shortly before the end of the minimum period is reached, the suction power of the suction unit is reduced so that the air flow falls below the upper limit value again. The reduction in the suction power occurs in particular within a time span of 1 s to 20 s, preferably from 5 s to 10 s, before the expiration of the minimum period. As a result, the time element in the control of the extractor smoke detector is reset again. Subsequently, an increase in the suction power above the upper limit value can be initiated without the output of an interrupt signal occurring.

[0025] According to a further method variant, the suction power of the suction unit is increased to shorten the transmission time so that the airflow does not exceed the upper limit value, or the suction power is increased only within a shorter time span than the minimum period during which the airflow exceeds the upper limit value, in particular when a warning signal is received from a higher-level fire alarm control panel or command center, for example via a signal line or bus, which connects the higher-level fire alarm control panel or command center to the extractive smoke detector. Alternatively, the connection between the extractive smoke detector and the fire alarm control panel and / or command center can occur wirelessly, for example via WLAN, Bluetooth or a mobile 3G, 4G or 5G data connection. The aforementioned (data) connection can be based on an Internet protocol.

[0026] The fire alarm control panel or command center can also be implemented as a cloud application in a cloud infrastructure. In this respect, the extractive smoke detector can receive warning signals from a higher-level cloud fire alarm control panel or cloud command center via the cloud. The warning signal is output when, for example, a fire alarm or an impending fire has been signaled to the fire alarm control panel or command center by at least one further extractive smoke detector in the vicinity of the extractive smoke detector (e.g. in the form of a pre-warning). Due to the spatial correlation, the probability of an actual fire increases around the installed extractive smoke detectors. In this case, a "leading" increase in the extraction power is advantageously demonstrated for the earliest possible fire detection.

[0027] According to a further method variant, a blockage signal is output when the air flow falls below a lower limit value for a minimum period of time.

[0028] According to a further method variant, the upper limit value of the air flow is set to 1.2 times the nominal air flow value. Alternatively or additionally, the lower limit value of the air flow is particularly set to 0.8 times the nominal air flow value. In a further alternative or additional manner, the minimum period is particularly set to a value in the region of 60 seconds to 600 seconds, preferably to a value of 90 seconds or 300 seconds, or to a value of 90 seconds ± 3 seconds or 300 seconds ± 3 seconds.

[0029] According to a particularly advantageous method variant, upper and lower limit values ​​for the air flow and a value for the duration of the minimum period are set relative to the nominal air flow value in accordance with national, regional or international standards, in particular European standard EN 54-20, preferably in a version dated February 2009.

[0030] According to the present invention, the object of the present invention is achieved with an extractor smoke detector, wherein the electronic control unit is further configured or programmed to output an interruption signal provided for normal operation if the acquired airflow exceeds a predetermined upper limit value for a minimum period of time. Furthermore, the control unit is configured or programmed to increase the suction power from the minimum signal level value only to the extent that the airflow does not exceed the upper limit value (by means of the power control unit). Alternatively, the control unit is configured or programmed to increase the suction power from the minimum signal level value (by means of the power control unit), i.e., to exceed the minimum signal level value only within a shorter time span than the minimum period of time in which the airflow exceeds the upper limit value.

[0031] In other words, the control unit is configured or programmed to increase the suction power from a minimum signal level value by means of the power control unit, ie to exceed the minimum signal level value only for a minimum period of time, so that the air flow as set exceeds the upper limit value.

[0032] By means of the specific increase in power and possibly time-limited suction power brought about by means of the power control unit, it is advantageously achieved that the output of false interruption signals by means of the fire detector unit is additionally prevented for a faster possible fire detection.

[0033] According to the first embodiment of the extractive smoke detector according to the invention, if the extraction power is only increased to such an extent that the airflow does not exceed or only does not exceed the nominal airflow value, the increase is in principle unlimited in time. However, in practice, regardless of whether a fire event is detected or not, the extraction power is preferably reduced again no later than the expiration of a predetermined waiting time, for example after 10, 20 or 30 minutes, so that the airflow reaches the nominal airflow value again.

[0034] With the return to normal operation, the noise development caused by the increased extraction power and the mechanical, life-reducing overload of the extractive smoke detector caused by the increase subsides again.

[0035] According to a second embodiment of the extractive smoke detector according to the invention, if an increase in the suction power occurs such that the airflow exceeds the nominal airflow value, for example by a factor of 1.2 to 5, preferably by a factor of 2 to 3, however, if the increase is limited in time to a minimum period from the point in time at which the upper limit value is exceeded, the output of an interrupt signal does not occur. The reduction in the suction power occurs in particular within a time span of 1 s to 20 s, preferably from 5 s to 10 s, before the expiration of the minimum period. Thereby, the time element in the control of the extractive smoke detector is reset again. The control unit can also be configured to, after the reduction in the suction power, start again to increase the suction power above the upper limit value without the output of an interrupt signal occurring.

[0036] According to an embodiment of the extractive smoke detector, the extractive smoke detector has a communication interface connected to the control unit. The control unit is configured to increase the suction power of the suction unit to shorten the transmission time if a warning signal is received from the communication interface.

[0037] In other words, in this case, the control unit is configured or programmed to increase the suction power of the suction unit by means of the power control unit so that the airflow does not exceed the upper limit value, or to increase the suction power only within a time span greater than the minimum period during which the airflow exceeds the upper limit value. The communication interface may be, for example, a communication interface for connecting a cable connection of a signal line or bus that connects a high-level fire alarm control panel or command center to the extractable smoke detector. Alternatively, the communication interface may be a wireless communication interface, such as a WLAN, Bluetooth or a mobile 3G, 4G or 5G data interface. For example, the aforementioned communication interface may be based on an Internet protocol.

[0038] According to one embodiment, the control unit is configured to reduce the suction power by means of the power control unit, in particular shortly before the end of the minimum period is reached, so that the air flow falls below the upper limit value again. "Shortly before the minimum period is reached" is intended to mean a time span of 1 s to 20 s, preferably 5 s to 10 s, before the minimum period expires.

[0039] According to a further embodiment, the control unit of the extractor smoke detector is configured or programmed to analyze the signal level of the fire characteristic and to evaluate whether a fire event exists. It is also configured or programmed to reduce the suction power of the suction unit after completing the analysis and evaluation and independently of the minimum period so that the airflow falls below the upper limit value again, in particular so that the airflow becomes set to the nominal airflow value again. In the event that no fire event can be detected, the extractor smoke detector is in normal operation again.

[0040] According to a further embodiment, the electronic control unit is configured or programmed to output a blockage signal if the derived air flow falls below a predetermined lower limit value for a predetermined minimum period of time.

[0041] As described above, "airflow" means the volume flow rate of air or air mass flow rate According to the physical relationship The latter two variables are linked to each other via the density ρ. According to the physical relation Density ρ and air pressure p, gas constant R of air f and the air temperature T. Therefore, the density ρ is proportional to the air pressure p and inversely proportional to the air temperature T.

[0042] For the operating method according to the invention and for the extractive smoke detector according to the invention, it can be assumed in principle that during normal operation of the extractive smoke detector, the density ρ is substantially constant, i.e. it changes by less than 3%, in particular by less than 2%. Such density changes therefore have no practical effect on the airflow monitoring of the extractive smoke detector. The air volume flow rate can be measured, for example, by means of a vane anemometer as flow meter. The air volume flow rate can be determined from the measured mean flow rate multiplied by the known inner diameter of the duct.

[0043] Alternatively, the air volume flow rate may be measured, for example, by means of a thermal air flow sensor such as, for example, a hot wire anemometer, the output signal of which is however the air mass flow rate If no significant changes in the ambient temperature, air pressure or air humidity in the extracted ambient air are expected, then the uncompensated thermal air flow sensor can be used as a flow meter. In cases where the use environment of the extractive smoke detector is more challenging, such as, for example, in cases where the ambient temperature and / or humidity vary greatly, this type of thermal air flow meter can include compensation facilities, as described in the aforementioned EP 2 407 946 A1. In order to take into account the acquired air temperature, the acquired air pressure and / or the acquired air humidity, the compensation facilities can have a temperature sensor and possibly a pressure sensor or a humidity sensor. Therefore, this kind of compensated thermal air flow sensor can act as a flow meter. The corresponding temperature, air pressure or air humidity sensors can be integrated into the suction unit or the hot wire anemometer itself.

[0044] According to one embodiment, the electronic control unit has a non-volatile memory storage for data access to upper and lower limit values ​​as well as nominal airflow values ​​and minimum period. The upper limit value is 1.2 times the stored nominal airflow value and the lower limit value is 0.8 times thereof. In particular, the minimum period is set to a value in the region of 60 seconds to 600 seconds, preferably to a value of 90 seconds or 300 seconds, or to a value of 90 seconds ± 3 seconds or 300 seconds ± 3 seconds. The non-volatile memory storage is, for example, an EPROM.

[0045] Alternatively, the upper and lower limit values ​​and the minimum time period may be set as a national, regional or international standard, in particular as the European standard EN 54-20, preferably with a version dated February 2009.

[0046] Finally, the suction unit of the extractive smoke detector may be a fan or a ventilator, the suction power of which increases with the increase of the fan speed n.

[0047] Preferably, the electronic control unit is a microcontroller, which is usually present or required in any event for the overall control of the extractive smoke detector. Furthermore, the microcontroller can have one or more integrated A / D converters for acquisition by measuring the aforementioned input variables, such as air volume flow rate, air mass flow rate, signal level and possibly air temperature, air pressure and air humidity. It can also have analog and / or digital input and output (I / O) units and a communication interface for outputting a fire alarm, an interruption signal or a blockage signal. In the microcontroller, upper and lower limit values ​​for the air flow, the nominal air flow value, the minimum time period and the minimum signal level can be stored in a non-volatile memory storage (EPROM) of the microcontroller. Furthermore, the power control unit and / or electronic components for signal preparation or signal processing of the aforementioned input variables can already be integrated in the microcontroller.

[0048] The object of the invention is finally achieved by a computer program product for carrying out the operating method according to the invention on an electronic control unit, in particular a microcontroller, of an extractive smoke detector. The electronic control unit comprises an electronic memory storage, such as a RAM or an EPROM, for storing the computer program product and for storing minimum signal level values ​​and nominal air flow values ​​as operating parameters. If appropriate, an upper air flow limit value, a lower air flow limit value and / or a minimum time period can be stored in the electronic memory storage as further operating parameters.

[0049] The computer program product is in particular an electronic file which can be loaded into the electronic memory storage of the electronic control unit. The computer program product can be stored, for example, on an optical or magnetic storage medium, such as a CD, DVD or Blu-ray disc or a magnetic hard disk. The computer program product can alternatively be stored on a memory stick, such as a USB stick. Finally, the computer program product can also be loaded, at least indirectly, into the electronic memory storage of the electronic control unit as a download via an intranet or the Internet.

[0050] By this means, the faster fire detection made possible by the present invention may advantageously be retrofitted into previously installed extractive smoke detectors by way of updating the operating software of the electronic control unit.

[0051] The invention and advantageous embodiments of the invention will now be described with reference to the accompanying drawings, in which:

[0052] Figure 1 is an exemplary structure of an extractor smoke detector in normal operation without smoke,

[0053] Figure 2 In case of fire detection Figure 1 Examples of

[0054] Figure 3 is an example of an extractive smoke detector according to the present invention.

[0055] Figure 1 An exemplary structure of an extractive smoke detector ASD in smoke-free normal operation is shown. Visible on the left is the suction / detector unit ADE as a modular unit, to which the suction duct R is attached, wherein a plurality of suction openings OF are arranged in a distributed manner. The latter are usually drilled holes leading into the suction duct R. The suction openings OF usually have a non-uniform cross-section in order to achieve substantially the same "hole sensitivity" in all suction openings OF. That is, in normal operation, each suction opening OF draws approximately the same suction volume per unit time. The calibration hole present on the right-hand side of the tube is marked with K. Figure 1The suction / detector unit ADE shown in the left-hand part of FIG. 1 comprises a suction unit L in the form of a fan, for example a radial fan, and a fire detector unit DET, which is arranged upstream in the flow direction. The mean flow velocity is denoted by v M Wherein the air flow or air volume flow rate extracted by the suction unit L corresponds to the mean flow velocity v M The volume per unit time is the product of the internal cross-section of the suction pipe R.

[0056] Figure 2 Shows the situation in which a fire is detected Figure 1 . In this example, ambient air with smoke to be detected is extracted at a suction opening OF symbolized by a flame symbol and conveyed via a suction duct R as far as a fire detector unit DET. A lightning symbol at the fire detector unit DET symbolizes a detected fire event. This is the case if the detection signal DL output by the fire detector unit DET exceeds a preset minimum detection level MIN. Figure 2 In the example of FIG. 1 , it can be seen how the extracted ambient air fills the transport length or pipe length ST with smoke. The associated transport time is denoted by T. The transport time T is determined by the mean flow velocity v M The product of t and the shown transmission length ST yields t As described in the introduction, the transmission time T may be as long as several minutes.

[0057] Figure 3 An example of an extractive smoke detector ASD according to the invention is shown. The functional construction of a suction / detector unit ADE is shown in detail. In the right-hand part of the suction / detector unit ADE implemented as a modular unit, a pipe connection AN is shown to which the suction pipe R is connected. The suction / detector unit ADE itself comprises a fire detector unit DET for determining by measurement a signal level DL of a fire characteristic. In the present example, the fire characteristic is the smoke concentration level. The extractive smoke detector ASD or the suction / detector unit ADE further comprises a power control unit DR, which is configured for setting a suction power P of the suction unit L. In the present case, the suction unit L is a fan, whose suction power P can be adjusted by means of varying the fan speed n L Furthermore, the extractor smoke detector ASD and / or the extractor / detector unit ADE has an airflow meter SEN to obtain the airflow of the extracted ambient air. Airflow is the volume flow rate of air or air mass flow rate The airflow meter SEN outputs a corresponding airflow measurement signal, which represents the air volume flow rate. or air mass flow rate

[0058] Furthermore, the extractive smoke detector ASD or the extractor / detector unit ADE has an electronic control unit MC which is connected to the fire detector unit DET, the airflow meter SEN and the power control unit DR. The latter is typically a microcontroller and is configured or programmed to adjust the extraction power P of the extraction unit L to a nominal airflow value NW for (smoke-free) normal operation with the aid of the power control unit DR. The adjustment of the extraction power P can take place in the form of an open-loop or closed-loop control loop, which is based on the currently acquired air volume flow rate compared to the nominal airflow value NW stored in an electronic memory storage MEM of the control unit MC. or air mass flow rate The control unit MC is further configured to output a fire alarm AL in the event of a fire being detected and to, during normal operation, if the acquired air flow Exceeds the preset upper limit When the minimum time period ZR is reached, an interruption signal U is output. The fire alarm AL and possibly the interruption signal U and the blockage signal V can be output by means of the electronic control unit MC to a bus interface of the suction / detector unit ADE, for example.

[0059] The control unit MC is further configured or programmed to increase the suction power P by means of the power control unit DR from a minimum signal level value MIN of the signal level DL, i.e. when the minimum signal level SIG is exceeded, in order to shorten the transmission time T of the extracted ambient air with smoke and / or with combustion gases through the suction duct R to the fire detector unit DET.

[0060] In particular, according to the invention, the control unit MC is configured or programmed to increase the suction power P by means of the power control unit DR from the detected minimum signal level MIN only to the set air flow. Not exceeding the upper limit For air volume flow rate Or for air mass flow rate The minimum signal level MIN and the upper limit Both can be stored in the electronic memory storage MEM for calculation comparison by the control unit MC.

[0061] Alternatively, the electronic control unit MC may be configured according to the invention to be activated only when the airflow is greater than Exceeding the upper limit In other words, the electronic control unit MC is configured or programmed to reduce the suction power P by means of the power control unit DR before (shortly after) the end of the minimum period ZR is reached, so that the air flow Fall to the upper limit again the following.

[0062] Furthermore, the electronic control unit MC may be configured to: Falls to a predetermined lower limit If the predetermined minimum time period ZR is reached, a blocking signal V is output. It can also be stored in the electronic memory MEM for calculation and comparison by the control unit MC.

[0063] Finally, the computer program product PRG and as operating parameters PAR the minimum signal level MIN and the nominal air flow value NW, and possibly the air flow The upper and lower limits of and / or the minimum time period ZR can be stored as a further operating parameter PAR in an electronic memory storage MEM of the electronic control unit MC, preferably in a non-volatile manner. The computer program product PRG is thus configured to carry out the operating method according to the invention on the electronic control unit MC, preferably on a microcontroller assisted by a processor of the extractive smoke detector ASD. It therefore comprises suitable program steps and program routines for operating, i.e. for controlling and monitoring, the extractive smoke detector ASD.

[0064] Reference Character

[0065] ADE Aspiration / Detector Unit

[0066] AL Fire alarm, alarm

[0067] AN Pipe connections, ports

[0068] ASD Extractive Smoke Detector

[0069] DET Fire Detector Unit

[0070] DL signal level

[0071] DR Power Control Unit, Driver

[0072] K Calibration hole

[0073] L Suction unit, fan, pump

[0074] MC Electronic Control Unit, Microcontroller

[0075] MEM memory storage, electronic memory, EPROM

[0076] MIN Minimum signal level

[0077] n L Fan speed

[0078] NW Nominal airflow value

[0079] OF suction opening, drilling

[0080] P Suction power

[0081] PAR Operation Parameters

[0082] R Suction pipes, piping systems

[0083] SEN Air Volume Meters, Flow Meters, Air Mass Flow Meters

[0084] ST transfer length

[0085] T Transmission time

[0086] U Interrupt signal

[0087] V blocking signal

[0088] V M Mean air velocity

[0089] ZR Period

[0090] Air mass flow rate

[0091] Air volume flow rate

[0092] Upper limit

[0093] Lower limit value.

Claims

1. A method for operating an extractive smoke detector (ASD), wherein the extractive smoke detector (ASD) is provided for detecting a fire in a space to be monitored and for outputting a fire alarm (AL) in the event of a fire being detected, wherein ambient air is extracted by means of a suction unit (L) of the extractive smoke detector (ASD) via a suction duct (R) of the extractive smoke detector (ASD) provided with a suction opening (OF) for smoke or combustion gases to be detected, and the ambient air is fed to a fire detector unit (DET) of the extractive smoke detector (ASD) for determining a signal level (DL) characteristic of a fire by measurement, and wherein for normal operation the suction power (P) of the suction unit (L) is set to generate an air flow through the suction duct (R) to a nominal air flow value (NW), and wherein the suction power (P) is increased from a minimum signal level (MIN) of the signal level (DL) in order to shorten the transmission time (T) of the extracted ambient air with smoke and / or combustion gases through the suction duct (R) to the fire detector unit (DET), Features - If the airflow Exceeding the upper limit If the minimum period (ZR) is reached, an interrupt signal (U) for normal operation is output, and - In any case, the suction power (P) increases from the minimum signal level (MIN) only to the airflow Not exceeding the upper limit degree, or - In any case, only the airflow Exceeding the upper limit The suction power (P) is increased from the minimum signal level value (MIN) within a smaller time span than the minimum period (ZR).

2. The method according to claim 1, wherein when a warning signal is received from a higher-level fire alarm control panel or command center, the suction power (P) of the suction unit (L) is increased to shorten the transmission time (T).

3. The method according to claim 1 or 2, wherein the signal level (DL) of the fire characteristic as to whether a fire event is present is analyzed and evaluated, and wherein after completion of the analysis and evaluation and independently of the minimum time period (ZR), the suction power (P) of the suction unit (L) is reduced so that the air flow Fall to the upper limit again the following.

4. The method according to claim 3, wherein the upper limit value The following are set as nominal airflow values ​​(NW).

5. The method according to claim 1 or 2, wherein if the air flow Fall to the lower limit When the minimum time period (ZR) is reached, a blocking signal (V) is output.

6. The method according to claim 5, wherein the air flow Upper limit of is set to 1.2 times the nominal airflow value (NW), where the airflow The lower limit of is set to 0.8 times the nominal airflow value (NW), and wherein the minimum period (ZR) is set to a duration of 90 seconds or 300 seconds.

7. The method according to claim 5, wherein the air flow About the upper and lower limits of the nominal airflow value (NW) And the duration value of the minimum time period (ZR) is set according to national, regional or international standards.

8. The method according to claim 7, wherein the standard is the European standard EN54-20, version dated February 2009, or the standard UL268 from the 6th or 7th edition.

9. An extractor smoke detector (ASD) having at least - a fire detector unit (DET) for determining the fire characteristic by measuring the signal level (DL), - Suction unit (L), - a power control unit (DR) for setting the suction power (P) of the suction unit (L), - a suction duct (R) connected to a suction unit (L) having a suction opening (OF) for extracting ambient air with smoke and / or combustion gases to be detected, - Airflow meter (SEN) to obtain the airflow of the extracted ambient air as well as - an electronic control unit (MC) connected to the fire detector unit (DET), the airflow meter (SEN) and the power control unit (DR), configured to adjust the suction power (P) of the suction unit (L) to a nominal airflow value (NW) for normal operation by means of the power control unit (DR), to increase the suction power (P) from a detected minimum signal level (MIN) to shorten the transmission time (T) by means of the power control unit (DR), and to output a fire alarm (AL) in the event of a detected fire, Features - The control unit (MC) is configured to: if the air flow obtained Exceeds the predetermined upper limit When the minimum period (ZR) is reached, an interrupt signal (U) for normal operation is output, and - the control unit (MC) is configured to increase the suction power (P) from the minimum signal level value (MIN) only to the air flow Not exceeding the upper limit degree, or - The control unit (MC) is configured to only Exceeding the upper limit The suction power (P) is increased from the minimum signal level value (MIN) within a shorter time span than the minimum period (ZR).

10. An extractive smoke detector (ASD) according to claim 9, wherein the air flow meter (SEN) is a flow meter.

11. An extractive smoke detector (ASD) according to claim 9, wherein the extractive smoke detector (ASD) has a communication interface connected to a control unit (MC), and wherein the control unit (MC) is configured to increase the suction power (P) of the suction unit (L) in order to shorten the transmission time (T) when a warning signal is received from the communication interface.

12. The extractive smoke detector (ASD) according to claim 9 , wherein the control unit (MC) is configured to reduce the suction power (P) by means of the power control unit (DR) shortly before the end of the minimum period (ZR) is reached, so that the air flow Fall to the upper limit again the following.

13. Extraction smoke detector (ASD) according to one of claims 9 to 11, wherein the electronic control unit (MC) is configured to analyze the signal level (DL) of the fire characteristic and to evaluate whether a fire event exists, and is configured to reduce the suction power (P) of the suction unit (L) after completing the analysis and evaluation and independently of the minimum period (ZR) so that the air flow Fall to the upper limit again the following.

14. An extractor smoke detector (ASD) according to claim 13, wherein the upper limit value The following are set as nominal airflow values ​​(NW).

15. An extractor smoke detector (ASD) according to one of claims 9 to 11, wherein the electronic control unit (MC) is configured to, if the acquired air flow Falls to a predetermined lower limit If a predetermined minimum period (ZR) is reached, a blocking signal (V) is output.

16. The extractive smoke detector (ASD) according to claim 15, wherein for the upper limit value and the lower limit value and nominal airflow value (NW) and minimum time period (ZR), the electronic control unit (MC) having a non-volatile memory storage (MEM), wherein the upper limit value 1.2 times the stored nominal airflow value (NW), and the lower limit is 0.8 times that, and wherein the minimum period (ZR) has a duration of 90 seconds or 300 seconds.

17. An extractor smoke detector (ASD) according to claim 15, wherein the electronic control unit (MC) has a non-volatile memory for storing upper and lower limit values ​​with respect to the nominal airflow value (NW). and the minimum time period (ZR) for data access, wherein the upper and lower limits and the minimum time period (ZR) is set according to national, regional or international standards.

18. An extractor smoke detector (ASD) according to claim 17, wherein the standard is the European standard EN 54-20, version dated February 2009, or the standard UL268 from the 6th or 7th edition.

19. A computer program product (PRG) for carrying out the method according to one of claims 1 to 6 on an electronic control unit (MC) of an extractive smoke detector (ASD), wherein the electronic control unit (MC) has an electronic memory storage (MEM) for storing the computer program product (PRG) and for storing a minimum signal level (MIN) and a nominal airflow value (NW) as operating parameters (PAR) and possibly for storing an airflow as a further operating parameter (PAR). Upper limit of airflow The lower limit of and / or minimum period (ZR).

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