Fire alarm system

The invention relates to a fire alarm system having a control center, with decentrally arranged detectors and having an input connected to the control panel communication bus for transmitting data and / or control signals between the detectors and the control panel. In the known fire alarm systems of this type, the detectors are connected via a wired channel to the communication bus. While such a wired connection guarantees high transmission security, but makes the entire system relatively inflexible for changes once a selected layout or function and / or availability of rooms. Because such changes entails usually that individual detector must change their location which is associated therein due to the required wiring with extensive under circumstances and in any case troublesome installation work. Subsequent installation of such fire detection systems with wire line between communication and detectors in existing buildings, especially in those in which a fire alarm system was not originally intended, designed to elaborate and expensive sometimes. This is especially true for historic buildings.

Despite the enumerated drawbacks of classical fire alarm systems with wire connections between the sensors and the control center, the nearby se wireless radio systems have not been able to prevail because they have some fundamental disadvantageous properties. On one hand, each problem area must be able to be achieved wirelessly, which may spark a high performance requires, on the other hand, the transmission power and thus the range for understandable reasons is limited. In addition, such radio systems are relatively unstable at larger distances.

Another not insignificant in these wireless Funksytemen aspect is the security against interference. The more extensive, such a radio network, the more measures must be taken to ensure the security mentioned. As an example, the radio system described in US Patent No. 5,155,469 mentioned above, wherein the sensor signals supplied to a transmitter, coded and then sent multiple times, which conditions apply for the breaks between these multiple releases. We see from this example that relatively expensive measures are necessary to achieve adequate immunity.

From EP-A-0513443 a building management system for controlling arranged in different rooms of a building peripheral devices, such as lamps, fans, blinds and the like are known. This system includes a control unit, a communication bus and connected to them mounted at fixed locations in the building and connected to the communication transponder. The transponders, which are provided for the wireless transmission of the bus signals to the peripheral devices, wherein the signal transmission is preferably performed by infrared radiation are respectively disposed in the spaces containing the devices.

Besides the fact that it is not meant for a fire alarm system, locally installed detectors to control from the control center, but to send alarm signals from the detectors to the control panel, this system can not be used because of the infrared radiation of a fire alarm system. Because the infrared radiation requires that between the transponder and the device to be controlled "visual contact" is made. And this means that the transponder and the device must be located in the same room, and that strict care must be taken that the connecting line between device and transponder is not interrupted, but this can be done relatively easily and unnoticed for example by moving furniture. Furthermore, the system must be installed because of the requirement, and transponders in the same room, for retrofitting, especially of historic buildings, unsuitable.

The invention provides a fire alarm system is now to be given, on the one hand to install with minimum effort and also easy to structural changes adaptable and therefore particularly suitable for historic buildings, and the other hand has a high reliability and security of data transmission. In addition to the to be created by the invention fire alarm system have a high degree of flexibility, which under flexibility the ability to adapt to structural conditions and needs to be understood.

This object is inventively achieved in that the detectors are connected to the communication either via a wired or a wireless channel, are in the latter case associated with the detectors in question to the communication bus connected relay means for receiving the detector signals and feeding them into the communication bus and that is with wireless connection between the detector and the detector communication outside disposed within the space to be monitored and the relay means of this and associated with each relay means comprises a plurality of detectors.

The inventive fire detection system is in terms of communication from within the installation of a completely new concept, by proposing a type of hybrid system with wired and wireless channels, the selection of the respective type of communication takes place so that the system with respect to transmission of technical constraints, transmission reliability and user benefit optimally is adapted to the external circumstances. So it is not so that the system as it were divided into two levels of communication Central / relay and relay / detector and a level wireline and other wireless communication is assigned, but also it is a direct communication between the central and detectors possible.

A first preferred embodiment of the inventive fire alarm system is characterized in that the wireless link is formed by a radio link.

If an inventive fire alarm system is to be installed for example in a hotel, then you will move the communication in the aisles and in each gear mounted depending on the length of one or more relay agent. For communication between the mounted in the rooms detectors and the associated relay means you will be where this is technically possible radio, select the wireless way. This dewegen because of the choice of the wireless path, provided that this does not preclude safety aspects, in any case, a user benefit results because no cables must be laid from the bus to the detectors. When in a funk-shielded space, such as in a shelter or in a basement with thick walls and / or metal door or in a safety-critical space (boiler room, oil tank), a detector should be installed, then you will this detector with because of the safety aspects connect a wire line to the communication bus.

The main advantage of the inventive system is dain that on the one hand as a system with fully wired detectors in terms of size practically unlimited, and that it is on the other hand so extremely flexible and adaptable, it the known wireless systems not only with respect to the required transmission power, stability or immunity but also in terms of flexibility surpasses.

A second preferred embodiment of the inventive fire alarm system is characterized in that the funds earmarked for the wireless connection detectors are designed to detect carbon monoxide.

A third preferred embodiment of the inventive fire alarm system is characterized in that said detector having an electrochemical sensor for measuring the concentration of carbon monoxide, which has a measuring electrode with a catalytically active material, a counter electrode with a carbon material and a related with measuring and counter electrode electrolyte contains.

The use of carbon monoxide sensors for fire detection has the advantage that the carbon monoxide, the most dangerous in fires gas is detected. As demonstrably die most victims of fire on carbon monoxide poisoning, Kohlenmoxid sensors are used with advantage where large numbers of people, for example in hospitals, hotels, public buildings and the like. The electrochemical sensors have the advantage that they are both very stable and have a lifetime of several years, and on the other hand, consume very little power, so that the force required to operate the detector battery also has a service life of several years.

In the following the invention with reference to an embodiment shown in the drawings is explained in detail; it shows:<dl id="dl0001" compact="compact"><dt>Fig. 1</dt><dd>a schematic section of a vehicle equipped with a fire alarm system according to the invention Hotel; and</dd><dt>FIG. 2</dt><dd>a schematic representation of a spark detector and a relay by means of the fire alarm system of FIG. 1,.</dd></dl>

Figure 1 shows approximately in center a gear 1, are installed in the fire detector 2 and a communication bus 3 and connect to the both sides with fire detectors 2 *, 2 'equipped rooms; above the Ganges 1 are spaces in the basement and below the Ganges 1 rooms from any floor are shown. The communication bus 3 is installed in the corridor of each floor, preferably in the ceiling of the hall, and the communication buses of all floors are connected to a common central. 4 As the figure can be seen further, it is also a relay 5 is installed in the hall 1, which latter is connected to the communication bus 3rd The structure of the relay 5 can be seen from the block diagram of FIG. 2.

Installed in gear 1 Fire detectors 2 are conventional fire detectors, for example, scattered light smoke detector or thermal detector, which emit an alarm signal upon detection of the respective fire characteristic. The fire alarm 2 are either wireless detectors which the alarm signals wirelessly, using radio, send, or wire detectors, which are connected to the alarm signals wired to emit and to this end to the communication bus 3 via a line (not shown). The spark detectors are denoted in Fig. 1 by the numeral 2 * and wire detectors are by reference numeral 2 '.

The rooms shown in the lower half of the figure are traditional hotel rooms HZ, each of which has a wet room NZ and is equipped with a wireless detector 2 *. If required, a wireless detector can be mounted 2 * in the wet NZ. The wireless detector 2 *, which are equipped according to FIG. 2 with a suitable radio transmitter 6, obtain the required electric power from a battery 7. The radio signals from wireless detectors 2 * received from the relay 5 and supplied through the communication bus 3 of the center 4. The relay 5 has to-the purpose, to a radio receiver, and a microprocessor 8. 9 The latter converts the received detector signals to corresponding digital signals. The frequency of the radio signals is selected so that those walls can safely penetrate, and is, for example above 300 MHz, preferably in the range of from about 430 or about 860 MHz. As Fig. 2 can be seen further, the relay 5 on also a printer connected to a power supply line geeignte power supply 10.

Preferably, the wireless detectors send 2 * in addition to the alarm signals at periodic intervals, such as every 30 to 60 minutes, a status signal which indicates that the detector battery 7 still has sufficient power. In the absence of this status signal * a fault is indicated in the control panel 4 for the respective wireless detectors. 2 In order to avoid a collision of different radio telegrams, the intervals between transmissions of the status signal may also vary randomly around a mean value.

The wireless detector 2 *, which can be designed to detect any fire parameters are preferably designed for the detection of carbon monoxide and assign a corresponding CO sensor 11 (Fig. 2). The CO sensors 11 may be incorporated into a multi-criteria detectors, which additionally includes a thermal sensor 12 and / or an electro-optical sensor for detecting smoke, but they can be used as fire detectors for different fire parameters directly and without the use of sensors. The signals of the two sensors 11 and 12 are an evaluation stage 13 which is connected to the radio transmitter. 6 The evaluation stage 13 is either a microprocessor or a system integrated circuit (ASIC).

As for statistics of international organizations, most victims of fires die from carbon monoxide poisoning, carry carbon monoxide detectors sure to save lives in and in particular there can be used with advantage where large numbers of people, say for example in hotels, hospitals, schools, public buildings and the like.

As carbon monoxide sensors 11 electrochemical sensors of the type 10444 described in WO-A-93 / are preferably used, which are sensors having a measuring electrode which contains a catalytically active material which may be a conversion of carbon monoxide to bring about, with a counter electrode, the contains a carbon material, and an electrolyte which is in contact with the measuring and the counter electrode. These sensors are the exceptionally stable and have a lifetime of several years, and they consume so little power that also in wireless detectors 2 * built-in battery 7 has a multi-year service life.

The embodiment illustrated in Figure 1 is not to be understood that in each floor or in each gear in the hotel only one relay 5 is mounted. Rather, the locations of the relays 5 are chosen so that only a relatively low power is required for transmitting the detector signals, which prolongs the life of the batteries detector 7 (FIG. 2). In determining the locations of the relay 5 is to ensure that the distance from the relay to the individual spark detectors 2 * does not exceed a certain maximum value, this value, which is dependent on the used building materials and the type of building construction, by practical try is determined. Usually you will be able to go out at a hotel of that for about 20 or 30 wireless detectors 2 * a relay is to be provided. 5

The illustrated in the upper half of Fig. 1 cut from the basement shows three areas, namely left a basement room KR, which is used for example as a storage room, because then a shelter SR and right a vestibule VR of the shelter SR. By cross-hatching of the walls of the shelter SR and VR hall indicated that these walls are specially reinforced. This reinforcement and the fact that no direct door between passage 1 and shelter SR exists and that both the door between shelter SR and vestibule VR as well as that from the vestibule VR is formed in the passage 1 through a specially armored door, have the effect of that a radio signal from the shelter or anteroom SR and VR would experience a very strong damping in the corridor 1, whereby this part of the building forms a harmful problem area. If one wanted to dominate this area with the usual measures harmful, then one would have to increase the transmission power of the mounted in the spaces concerned spark detectors to undesirably high values.

According to the representation a spark detector is 2 * provided only in the radio technology not so problematic basement KR, whereas each one of the communication bus 3 via a lead wire connected detector 2 is mounted in the shelter SR and in the anteroom VR '. This wire detectors are for example of the type of<i>AlgoRex</i>Annunciator of Cerberus AG (<i>ALGOREX</i> - Registered trademark of Cerberus AG, Männedorf, Switzerland); they draw their electrical power from the bus 3 and they are designed for two-way communication with the control panel. 4

Of course, in the illustrated fire alarm system, the use of wire detectors 2 'is not limited to radio coverage areas of concern, but you can use wire detector in such rooms and areas of the building, which must meet especially high security requirements or where an increased fire risk. When installed in the corridor 1 2 detectors the type of communication is deliberately kept open in order to indicate that both types of communication can be used here.

As the embodiment described shows the following alternative in this system for communication between headquarters and 4 detectors 2, 2 * and 2 ':<ul><li>Communication 3 + 5 + relay wireless detectors 2 *; or</li><li>Communication 3 + Wire Detector 2 '.</li></ul>

Each of these variants has at least a substantial advantage over the other. The variant wireless detector has the advantage of high flexibility and adaptability and it requires less installation effort. The variant line Detector asked the advantage of a very stressed safety and extremely low susceptibility to interference and allows an almost unlimited expansion of the plant.

The main advantage of the system described consists in the fact that it offers both options in a single system, and that the creator / operator has the option to choose as it were from room to room or from detector to monitor for the optimum in each case for him opportunity , For which of the two options he chooses, depends on several criteria, which can be put on the following simple terms: At large distances line Detector for problem areas wire detectors and wireless detectors otherwise.

Something detallierter are the criteria set out as follows:<ul><li>Where it is rendering technically possible, the wireless connection is selected (wireless detectors 2 *).</li><li>Where an appropriate user benefits resulted, the wireless connection is selected (wireless detectors 2 *).</li><li>Where required by the safety, the wired connection is selected (line Detector 2 ').</li></ul>

The latter criterion can be broken down as follows:<ul><li>Where the harmful path loss is too large and / or where the radio distances are too large is selected, the wired connection (line Detector 2 ').</li><li>Where particularly high demands in terms of reliability exist, the wired connection is selected (line Detector 2 ').</li><li>Where nearby radio interferers are present, the wired connection is selected (line Detector 2 ').</li></ul>

Another important advantage of the described system is that the electrochemical sensors to measure the concentration of carbon monoxide are so stable and durable and so consume little energy, that their use in Brandmeldem the reliability and safety of the system unit to the wireless communication increased very significantly.