EP1103937B1 - Fire detector - Google Patents

Abstract

The fire alarm (1) comprises a light source (7), measuring chamber (9) and a light receiver (8), all housed within an optical module (5). A temperature sensor (13) and the light receiver (8) are both connected to an evaluation electronic module (6). A sensor (12) for combustion gas, e.g. CO, is additionally provided. The electronic module (6) comprises a fuzzy logic controller, which compares the output signals of individual sensors (5,12,13) and determines the type of fire. For each type of fire a different application specific algorithm is selected. The fuzzy logic associates smoke concentration with combustion gas concentration and with a parameter formed from the gradients of temperature and of smoke gas.

Description

The present invention relates to a fire detector with a light source, a measuring chamber and a light receiver having optical module, a temperature sensor, a additional sensor for at least one fire gas and an evaluation of the linkage the signals of the individual sensors.

For fire alarms of this type, which are referred to as multiple or multi-sensor fire detectors, the optics module serves for the detection of smoke and the temperature sensor for detection the heat that occurs when a fire occurs. The optics module can either be from Smoke particles scattered or measured by this attenuated light of the light source. In the first case, it is the optical module of a scattered light detector and in the second case that of a point extinction or transmitted light detector. In both cases, the optics module designed so that no disturbing extraneous light and smoke very easily in the measuring chamber can penetrate. The temperature sensor serves both to increase the sensitivity as also to improve the false alarm safety of the scattered light detector. A scattered light detector with A temperature sensor is known, for example, from EP-A-0 654 770.

The scattered and transmitted light detectors are extremely sensitive and can cause fires detect with high security. However, the high sensitivity can in certain cases too False alarms lead, which is undesirable for several reasons. Otherwise, that false alarms at least tend to attract the attention of the security personnel concerned reduce, demands in most countries the fire department and / or the police for False alarms caused a compensation, which may be with the number the false alarms progressively increases. For this reason, enjoy the false alarm safety today with fire detectors very high priority.

In a fire detector of the type mentioned in JP-A-06 301 870 described the false alarm safety is improved by the fact that the evaluation of the sensor signals in a fuzzy logic takes place.

The invention is now the false alarm safety of the detector with a simultaneous reduction its response time further improved and it should also a more homogeneous Response of the detector can be achieved. Homogeneous response means that the detector should respond to different fires about the same and not on the one type from fire extremely fast and to another extremely slow to not at all.

This object is achieved by the fact that the transmitter for the Diagnosis of the respective type of fire according to one of the test fires TF1 to TF6 of the European standard EN-54 is formed and that due to this diagnosis the selection a special application-specific algorithm for processing the sensor signals he follows.

A first preferred embodiment of the inventive fire alarm is characterized characterized in that the transmitter has a fuzzy controller for performing the has said link.

• TF1: Holzbrand
• TF2: Holzschwelbrand
• TF2: Luntenschwelbrand
• TF4: Schaumstoffbrand
• TF5: Heptanbrand
• TF6: Alkoholbrand.

There are the following six different test fires (abbreviated TF) according to the European standard EN-54:

• TF1: wood fire
• TF2: Wood smoldering fire
• TF2: Lunchtschwelbrand
• TF4: foam firing
• TF5: heptane fire
• TF6: Alcohol burn.

The optical module of the fire detector according to the invention can either be designed in such a way that that in the measuring chamber that of smoke particles scattered or weakened by these Light of the light source is measured. In the first case, it is the detection principle a stray light, in the second case to the Detektiosprinzip a transmitted light detector. It can the scattered light detector as a forward or backward spreader or as a forward and backward spreader be educated. The latter has the advantage that, based on the scatter at different Scattering angle determines which type of smoke is present; see WO-A-84 01,650th

The inventive multi-sensor Brandmeider, the an optical smoke sensor, a Temperature sensor, a fire gas sensor and a fuzzy controller contains and in which for Each kind of firing is provided with a special application specific algorithm Possibility, by linking the signals of the sensors in the fuzzy controller the respective Detect the type of fire and select the appropriate algorithm. This will on the one hand the false alarm (robustness) improves the detector, and on the other hand, by appropriate choice of application-specific algorithms a more balanced response be achieved by the detector.

In addition, there is the possibility of a kind of problem diagnosis by the fuzzy controller monitors whether certain disturbances still lie below the respective alarm thresholds heaped occur. The fuzzy controller can such disturbances to the control center or via a suitable Report communication interface to the operator and in this way indicate potential sources of interference, possibly caused by a wrong application of the detector concerned.

A second preferred embodiment of the inventive fire alarm is characterized characterized in that in the fuzzy controller, a connection between the smoke concentration, the Concentration of the flue gas to be detected and one of the gradient of the temperature and the gradient of the flue gas formed parameter takes place.

A third preferred embodiment of the inventive fire alarm is characterized characterized in that said parameter by the quotient of the temperature gradient and the flue gas gradient is formed.

A fourth preferred embodiment of the inventive fire alarm is characterized characterized in that the additional sensor for a fire gas is a CO sensor.

A fifth preferred embodiment of the inventive fire alarm is characterized characterized in that the light source of the optical module for emitting radiation in the wavelength range of visible light is formed.

In a sixth preferred embodiment, the wavelength is that of the light source emitted radiation in the range of blue or red light and is preferably 460th nm or 660 nm.

A further preferred embodiment of the fire detector according to the invention is characterized characterized in that in the beam path between the light source and the light receiver at least a polarizing filter is provided.

A further preferred embodiment is characterized in that the at least a polarizing filter a so-called active polarizer with electrically adjustable polarization plane is.

Preferably, the active polarizer is formed by a liquid crystal display whose polarization plane is adjustable by applying a voltage.

Fig. 1 eine schematische Schnittdarstellung eines erfindungsgemässen Brandmelders; und

Fig. 2 ein vereinfachtes Blockschema der Signalverarbeitung.

In the following the invention with reference to an embodiment and the drawings will be explained in more detail; it shows:

Fig. 1 is a schematic sectional view of a fire detector according to the invention; and

Fig. 2 is a simplified block diagram of signal processing.

The fire detector 1 shown in an axial section in Fig. 1 is essentially an additional Sensors for fire characteristics of advanced optical smoke detectors, as shown a scattered light detector. Since such optical detectors are assumed to be known, are they are not described here. In this connection, reference is made to EP-A-0 616 305 and EP-A-0 821 330. The optical smoke detector can also by a so-called Punktxtinktions- or transmitted light detector may be formed, as described for example in EP-A-1 017 034 is described.

The fire detector 1 shown consists in a known manner from a detector insert 2, the in a preferably mounted on the ceiling of the space to be monitored socket (not shown) can be fastened, and from a placed over the detector insert 2 detector hood 3, in the area of their in the operating state of the detector directed against the space to be monitored Dome with smoke inlet openings 4 is provided. The detector insert 2 comprises in essentially a box-like base body, facing to the detector tip Side of an optical module 5 and the detector base side facing an evaluation 6 is arranged.

The optical module 5 consists essentially of a light source in a scattered light detector 7 and a light receiver 8 containing measuring chamber 9, which by not shown Medium against external light is shielded from the outside. The optical axes of an infrared or a red or blue light emitting diode (IRED or LED) formed light source 7 and the Light receiver 8 are kinked to each other, with this course and by blinding prevents light rays on the direct route from the light source 7 to the light receiver 8 can get. The light source 7 sends short, intense light pulses in the central part the measuring chamber 9, wherein the light receiver 8, although this central part of the measuring chamber 9, but not the light source 7 "sees".

The light of the light source 7 is scattered by penetrating into the scattering room smoke, and a Part of this scattered light is incident on the light receiver 8. The receiver signal generated thereby is processed by the transmitter 6. During processing, the receiver signal becomes compared in a known manner with an alarm threshold and at least one pre-alarm threshold, and the transmitter 6 are at the alarm threshold exceeded by the receiver signal at an output 10 from an alarm signal. It is through intelligent signal processing Ensures that the delivery of the alarm signal at the lowest possible smoke values follows, but without unacceptable false alarms.

In the beam path between the light source 7 and the light receiver 8, a so-called active polarizer 11, which is a polarizer with a rotatable plane of polarization, provided be able to measure the light scattering in the two polarization planes. This active Polarizer is preferably by an electronic polarizing plate with a liquid crystal formed, which rotates their polarization plane by 90 ° when applying a voltage. The measurement the polarization degree, that is the polarized scattered light in the two polarization planes, can shorten the response time of the detector 1 to certain test fire and thereby to lead to a more homogeneous response.

1, the fire detector 1 in addition to the optical module 5 contains two more sensors for fire parameters, namely a CO sensor (in general: fire gas sensor) 12 and a temperature sensor 13. A suitable CO sensor is in the EP -B-0 612 408 (see also EP-A-0 803 850), as temperature sensors have NTC thermistors proven (see the smoke detector PolyRex the fire detection system AlgoRex - PolyRex and AlgoRex are registered trademarks of Siemens Building Technologies AG, Cerberus Division, formerly Cerberus AG).

Theoretical considerations and practical fire tests have given the correlations between the different fire parameters measured with the different sensors optics module 5, CO sensor 12 and temperature sensor 13 in the following table. Of course, the amount of smoke or smoke concentration is measured as a further fire parameters; this is the known function of an optical smoke detector and thus of the optical module 5. brand parameters TF1 TF2 TF3 TF4 TF5 TF6 CO concentration large low very large low low low Gradient CO / gradient T medium low low medium large large Gradient T very large low low large very large very large degree of polarization very large low low large very large low

• Die CO-Konzentration eignet sich besser als alle anderen Parameter zur frühen Detektion von TF3 und korreliert hier mit der Rauchkonzentration.
• Der Quotient Gradient CO durch Gradient Temperatur eignet sich sehr gut zur frühen Detektion von TF5 und TF6 und korreliert hier mit dem Temperaturanstieg.
• Der Temperaturanstieg eignet sich sehr gut zur frühen Detektion von TF1, TF5 und TF6 und korreliert mit Ausnahme von TF6 (kein Rauch) mit dem Polarisationsgrad. Man kann dieses Ergebnis so interpretieren, dass Brände, die viel Hitze generieren, ziemlich kleine Aerosolteilchen erzeugen. Die Korrelation zwischen Temperaturanstieg und Polarisationsgrad kann als Alarmbestätigung und somit für die Erhöhung der Robustheit des Melders benutzt werden.

The table shows the following results:

• The CO concentration is better than any other parameter for the early detection of TF3 and correlates with the smoke concentration.
• The gradient gradient CO gradient temperature is very suitable for the early detection of TF5 and TF6 and correlates with the temperature rise.
• The temperature rise is very well suited for the early detection of TF1, TF5 and TF6 and correlates with the degree of polarization except TF6 (no smoke). One can interpret this result in such a way that fires that generate a lot of heat generate rather small aerosol particles. The correlation between temperature rise and degree of polarization can be used as alarm confirmation and thus for increasing the robustness of the detector.

The table also shows that the parameters CO concentration, quotient Gradient CO is individually diagnosed by gradient T and smoke concentration all six types of fire can be. This means that with the help of these parameters the signature of a fire clearly is recognizable. On the other hand, the parameters also allow CO concentration, degree of polarization and smoke concentration a determination of the type of fire, but with the exception of TF6, which can not be recognized by these parameters. The measurement of the degree of polarization In addition has the advantage that even in cases where the temperature is not fast Enough is rising, the kind of fire can be detected. This case can be, for example, in high rooms enter.

As shown schematically in FIG. 2, the signals of the three sensors, optical module 5 for the smoke concentration and the degree of polarization, CO sensor 12 and temperature sensor 13, a component of the evaluation 6 forming diagnostic stage 14 is supplied, which in essentially contains a fuzzy controller. In the diagnostic stage 14, the signals of Sen-. sensors are linked and analyzed, and the type of fire is determined from this analysis. After all the appropriate algorithm for the respective type of fire is selected and for the evaluation the sensor signals used. As already mentioned, the fuzzy controller can also be used for Diagnostic purposes, used to display problems.

The optical module 5 of the inventive fire detector corresponds functionally one usual scattered light detectors with forward or backward scattering, or a scattered light detector with forward and backward sweep, or a point extinction or transmitted light detector. One An essential component of the inventive fire detector is the sensor 12 for the at least a combustion gas, which is preferably a CO sensor.

It should be noted that it can be quite advantageous to use other types of Brandmeldem additionally equipped with a fire gas sensor, in particular a CO sensor. Such fire detectors are, for example, the so-called linear smoke detectors or Beam detectors such as the DLO1191 type from Siemens Building Technologies AG, Cerberus Division, and the flame detectors, such as the DF1190 type from Siemens Building Technologies AG, Cerberus Division.

Claims (11)

1. Fire detector having an optical module (5) comprising a light source (7), a measuring chamber (9) and an opto-receiver (8), having a temperature sensor (13), an additional sensor (12) for at least one combustion gas and evaluation electronics (6) for logically combining the signals from the individual sensors (5, 12, 13), characterized in that the evaluation electronics (6) are designed to diagnose the respective fire type in line with one of the test fires TF1 to TF6 from the European standard EN-54, and in that this diagnosis is taken as a basis for selecting a special application-specific algorithm for processing the sensor signals.
2. Fire detector according to Claim 1, characterized in that the evaluation electronics (6) have a fuzzy controller for performing said logic combination.
3. Fire detector according to Claim 2, characterized in that the fuzzy controller logically combines the smoke concentration with the combustion gas concentration and with a parameter formed from the gradient of the temperature and from the gradient of the flue gas.
4. Fire detector according to Claim 3, characterized in that said parameter is formed by the quotient of the temperature gradient and the flue-gas gradient.
5. Fire detector according to one of Claims 1 to 4, characterized in that the additional sensor (12) for a combustion gas is a CO sensor.
6. Fire detector according to one of Claims 1 to 5, characterized in that the light source (7) in the optical module (5) is designed to transmit radiation in the wavelength range of visible light.
7. Fire detector according to Claim 6, characterized in that the wavelength of the radiation transmitted by the light source (7) is in the range of blue or red light and is preferably 460 nm or 660 nm.
8. Fire detector according to Claim 6, characterized in that the beam path between the light source (7) and the opto-receiver (8) contains at least one polarization filter (11).
9. Fire detector according to Claim 8, characterized in that the at least one polarization filter (11) is an "active polarizer" with an electrically adjustable polarization plane.
10. Fire detector according to Claim 9, characterized in that the active polarizer is formed by a liquid crystal display whose polarization plane can be adjusted by applying a voltage.
11. Fire detector according to Claims 3 and 10, characterized in that measuring the smoke concentration involves the optical module (5) determining the degree of polarization of the radiation scattered in the measuring chamber (9) from the light source (7).

Images