EP3267412A1 - Smoke and thermodifferential blade - Google Patents

Abstract

The invention relates to a smoke and thermal difference meter (1) having a smoke chamber (10) through which air can be conducted from an inlet opening (20) to an outlet opening (25) along a flow path (110). By means of a smoke sensor (30, 35) and a temperature sensor (40), the smoke particle concentration and the temperature of the air can be determined. The measurement data of the sensors (30, 35, 40) can be stored and evaluated by an evaluation unit (50).

Description

The invention relates to a smoke and thermal differential meter for detecting fires and / or overheating of systems, in particular electrical installations by means of measurement of smoke density and temperature according to the preamble of claim 1.

Usually electrical systems and in particular electrical distribution systems are installed in confined spaces. This can be the case, for example, in control cabinets for medium and low-voltage systems. In addition, said cramped conditions also prevail in control cabinets for systems or in server cabinets for computer systems.

Such cabinets are usually installed in buildings and there preferably arranged in a room niches, installed, tested and also put into operation, so as little as possible otherwise usable space is blocked by the electrical system.

The failure of these electrical systems very often leads to serious disruptions in the overall flow of each given production, manufacturing or other total assets, such as the entire electrical system in households.

Often fires and / or overheating are the cause of failure of individual electrical systems that arise, for example in control cabinets by overloading electrical components or by defective or faulty contacts. If the fires and / or overheating are not noticed in time, they can spread unhindered.

Fires of electrical installations can have different causes. A common cause of fire are the cables themselves. Thus, electrical cables are made of soft electrolytic copper, so that they yield under the mechanical load of terminals. As a result, sometimes the connection between the terminal and the electrical cable is partially or completely released, which increases the contact resistance of the connection. Under electrical load it comes increasingly to Schmorstellen with considerable fire risk.

Another source of fires is equipment built into electrical equipment (e.g., distribution equipment). Such resources may be power supplies of intercoms, timers, etc. These resources are subject to an aging process, which can also lead to defects, which very often lead to heat and Schmorstellen.

An important indicator of the existence of a fire is smoke. Smoke is produced by the combustion of a combustible material and consists of smoke particles floating in the air. Smoke is therefore an important fire indicator. The smoke concentration is the concentration of smoke particles floating in the air. Therefore, it is now mandatory in many countries to use smoke detectors for registering fires as fire detectors.

Conventional methods for the detection of smoke, as occurs in Schmorstellen or resulting smoldering, have the disadvantage that often a relatively long period of time is between fire and fire detection by a fire alarm. This is due to the fact that in the air duct, especially in electrical systems by ventilation or air conditioning systems have strong turbulence of the air. Smoke particles that are in the air are thus distributed more rapidly to the total available air volume, which leads to delays in the response of such fire detectors. In particular, in large total electrical systems, which consist of several electrical units, which are distributed over several cabinets, it is particularly important that any overheating or fires in the units are detected early.

For this purpose, special suction devices are used in control cabinets, which are connected to a central flue gas detection. It may well be connected to a flue gas detection several cabinets. The aspirators suck in ambient air and forward it to a flue gas detection Here, the installation of the intake and the connection of the suction with the flue gas detection is complicated. In addition, only one suction device is usually mounted per cabinet. In addition, the air temperature in a control cabinet alone can not be measured by the suction device.

In particular, the overheating of electrical systems is usually preceded by smoke, since the most common cause of overheating is a short circuit or overload of components or cable connections. Object of the present invention is therefore to provide a reliable and compact device for detecting overheating and fire of electrical systems, which is easy to retrofit into existing cabinets, and has a low installation and manufacturing costs.

According to the invention, this object is achieved by a smoke and thermal differential meter having the features of claim 1.

In a smoke and thermal differential meter having at least one smoke chamber with at least one inlet opening which is connected to at least one outlet opening by a flow path, at least one smoke sensor, at least one temperature sensor and an evaluation unit, wherein smoke and heated air from a system to be monitored of the at least one According to the invention, the at least one smoke sensor and the at least one temperature sensor record measured values within the smoke chamber and the measured values of the at least one smoke sensor and the at least one temperature sensor can be conducted to the evaluation unit are.

It is particularly advantageous in this case that for the detection of fires or for the detection of overheating, the temperature of the air, which is located in the smoke chamber, is measured directly from the temperature sensor. Thus, the evaluation unit, which receives measurement data from the temperature sensor, can detect an increased air temperature in the smoke chamber. In particular, by the analysis of the air temperature as a function of time by the evaluation unit, a temperature increase can be detected. By the evaluation is then preferably at a particularly high temperature rise in a short period of time and / or when exceeding a temperature threshold, an abnormal state detected.

The evaluation unit particularly advantageously evaluates the smoke sensor and the temperature sensor for detecting fires or for detecting overheating, so that the reliability of a fire detection is increased and the probability of a false alarm is reduced by a faulty measurement database. A further advantage is that by incorporating a temperature sensor, it is possible to detect heating of the air in a control cabinet that leads to smoke development. In a preferred embodiment, the inlet opening of the outlet opening opposite. Particularly preferably, the smoke and thermal differential meter is arranged above the system to be monitored.

It is preferably provided that the smoke and thermal difference meter has at least one signal unit.

Particularly advantageous is the inclusion of a signal unit, since the operator of the smoke and thermal difference meter can be informed by a signal of the signal unit on a detection of a temperature increase, the detection of smoke or the presence of a fire. Preferably, the signal unit can be controlled by the evaluation unit, whereby the signal unit, depending on the result of the evaluation of the measured data of the temperature sensor or the smoke sensor can give a different signal. Particularly preferably, the signal of the signal unit is optically and / or acoustically. In this case, in a preferred embodiment, the optical signal is given by a light-emitting diode (LED), a flashlight or an all-round light. The acoustic warning signal can be given in a further preferred embodiment by a speaker, a bell a whistle and / or a bugle. These acoustic or optical signal transmitters particularly preferably form the signal unit.

Preferably, it is provided that the smoke and thermal difference meter has at least one air flow measuring means.

The inclusion of an air flow measuring device in the smoke and thermal difference meter is advantageous because the database for the determination of overheating and / or fire with or without smoke development by the evaluation unit is improved by including a further sensor. In particular, the air flow is an important parameter for the determination of the smoke content in the air, as strongly moving air quickly circulates and thus a weak smoke is quickly distributed over a large volume of air. In particular in air-conditioned electronic installations, such as e.g. Control cabinets or cabinets for IT systems are subject to air-conditioned conditions in which there is a high volume of air. An incipient smoke development is then only conditionally detectable by the smoke sensors. The evaluation unit can attach a corresponding correction in the advantageous presence of information about the height of the air flow and react accordingly sensitive to the measured values of the smoke sensor. Likewise, tearing off the airflow may indicate a failure of active ventilation, thereby increasing the risk of overheating. Preferably, the air flow measuring means is arranged at the inlet opening or at the outlet opening of the smoke chamber, since the air flow is not influenced here by the flow path of the smoke chamber. In addition, the air flow through the smoke chamber can be determined by this arrangement. Particularly preferably, the measured values of the airflow meter can be conducted to the evaluation unit.

In one embodiment, it is therefore provided that the smoke and thermal difference meter has at least one transmitter.

Advantageously, a transmitter in a smoke and thermal differential meter is used to transmit the evaluation results of the evaluation and / or status information of the sensors to another location. Thus, for example, a control module of an external security system may preferably be provided as a receiver, which receives information from a plurality of smoke and thermal difference meters via its transmitters. The transmitters are preferably connected to one or more receivers by means of a line, particularly preferably wirelessly.

Preferably, it is provided that the smoke and thermal difference meter has a buffered power supply unit. An advantage of this embodiment is that when the power supply of the smoke and thermal difference meter collapse, a power supply of the entire system and in particular of the sensors, the evaluation unit and the signal unit is ensured. The buffered power supply may be formed by a battery, an accumulator or a capacitor.

A particularly expedient embodiment provides that the smoke and thermal difference meter has at least one potential-free contact.

An advantage of a potential-free contact is that a circuit or the system to be monitored is electrically isolated from the smoke and thermal difference meter switchable. Particularly preferably, the circuit or the system to be monitored can be separated from a power supply by means of the potential-free contact. Particularly preferably, the circuit to be monitored or the system to be monitored via a main contactor by the potential-free contact is switched off. Furthermore, it is provided in a preferred embodiment that the potential-free contact can be controlled or switched by the evaluation unit.

A preferred embodiment provides that the smoke chamber is antistatic. It is advantageous that any smoke particles can not settle in the smoke chamber by a static charge of the smoke chamber. In particular, it is then ensured that the flow regime and the optical properties inside the smoke chamber are not influenced by electrostatic deposits of smoke particles. This is particularly important if optical sensors are used to detect the smoke and no air flow meter is used.

Particularly preferred is the embodiment, wherein the at least one smoke sensor comprises an infrared transmitting element and an infrared receiver element. Infrared sensor elements are advantageous because the measurement of backscatter occurs in a region of non-visible light. Thus, the measurement is not disturbing for the users of the smoke and thermal difference meter. In addition, the measurement is less sensitive to interspersed light waves in the visible frequency spectrum. The infrared sensors determine the proportion of infrared radiation emitted by an infrared transmitting element, which arrives at an infrared receiver element via a specific path or the infrared radiation which is reflected in a specific area of the smoking chamber. The reflection of infrared radiation takes place in both cases on particles - including smoke particles - in the sampled air volume, so that the proportion of reflected or transmitted infrared radiation is a measure of the particle concentration.

A further preferred embodiment provides that the measured values of the at least one smoke sensor, the at least one temperature sensor and / or the air flow measuring means can be transmitted wirelessly or by cable to the evaluation device.

This is advantageous since a transmission of the measured values to the evaluation device, both by cable and by wire hole, ensures that the evaluation device can access the measured values of the sensor system or at least part of the sensor system. Sensors that are not connected to the evaluation, are therefore not evaluated by this and are connected in an alternative embodiment directly to the signal unit.

Furthermore, it is particularly expedient that the at least one temperature sensor has a measurement resolution, by which a temperature change rate of 3 K / s can be determined.

The ability to determine a rate of change of temperature allows the smoke and differential temperature meter to quickly detect an abnormal temperature rise by means of the appropriately designed temperature sensor. At the same time, the temperature sensor formed in this way is able to accurately determine a temperature of at least 3 K. Preferably, a platinum resistance thermometer or another PTC thermistor is used as a temperature sensor. Alternatively, it is also possible to use thermistors or thermocouples as temperature sensors. Particularly preferably, the temperature sensor is arranged slightly offset on the side of the smoke chamber, which faces the plant to be monitored.

Alternatively, it is provided according to an embodiment that the at least one signal unit, the at least one air flow measuring means, the at least one transmitter and / or the power supply unit are modularized.

The modularization of the units, the measuring means and / or the sensor is advantageous because the individual modules then no longer have to be arranged directly on the smoke and thermal difference meter. As a result, the actual sensor part of the smoke and thermal difference meter with the temperature sensor and the smoke sensor can be very compact. The modularization also makes it possible to subsequently add or remove one or more modules, whereby the smoke and thermal difference meter can be adapted or reused for changing purposes.

A particularly expedient embodiment provides that measurement data of the at least one temperature sensor and of the at least one smoke sensor can be registered and processed by the evaluation unit measurement data.

The evaluation unit preferably has an internal data processing, which adjusts the measured values of the sensors against models or reference values. By processing the data, a more accurate determination of the condition of the equipment to be monitored with regard to the risk of fire or the presence of a fire is possible.

In particular, by processing the data susceptibility to measurement errors of individual sensors can be reduced if all sensors are evaluated holistically. Particularly preferably, the measured values of the sensors can be calibrated individually or in their entirety with reference data and / or models by the evaluation device, so that possible overheating and / or the presence of a fire can be detected. In the event that an abnormal state is detected, a specific statement about the origin of the abnormal state can be made, in particular by comparison with reference data and / or models.

Furthermore, a preferred embodiment provides that the signal unit is designed as a piezoelectric transducer. A piezoelectric transducer is advantageous because in a compact design, a comparatively high sound pressure can be generated. Preferably, the piezoelectric transducer is controllable such that it emits a periodic acoustic signal. Particularly preferably, the piezoelectric transducer emits an acoustic signal with changing frequency.

According to one embodiment, it is particularly advantageous that the smoke and thermal difference meter can be arranged in an electrical standard distributor or an electrical distribution cabinet. By this preferred embodiment, the smoke and thermal difference is particularly close to the system to be monitored can be arranged, whereby a particularly reliable measurement is possible. Preferably, the standard distributor, in which the smoke and thermal difference meter can be arranged, designed according to DIN 43880. Alternatively, the distribution cabinet in which the smoke and thermal difference meter is arranged is preferably designed in accordance with DIN EN 61439. Particularly preferred is the smoke and thermal difference meter on a housing which can be arranged on a top hat rail. Advantageously, the design of the housing in its width in a further preferred embodiment of the smoke and thermal difference in the DIN rail mounting at least 4 and a maximum of 5 division units (TE). Particularly preferably, the housing is equipped with a locking clip for DIN rail mounting.

In a preferred embodiment, provision is therefore made for the smoke and thermal difference meter to have a housing with a standard device size for installation in standardized receptacles. This is advantageous because the dimensions of the smoke and thermal difference meter then correspond to the dimensions of other devices that are designed according to the same standard, and so a particularly compact design of a monitored system is possible.

In a further embodiment it is provided that the smoke chamber is arranged in the lower part of the smoke and thermal difference meter and the smoke and thermal difference meter is preferably arranged with the inlet opening above the system to be monitored.

Furthermore, it is provided in an alternative embodiment that the smoke and thermal difference meter has a second smoke chamber. Particularly preferably, the sensor system of the second smoke chamber is constructed redundantly to the sensor system of the first smoke chamber. In this case, the second smoke chamber is preferably arranged on a side facing away from the device to be monitored.

A particularly expedient embodiment provides that expansion modules of the smoke and thermal difference meter include the sensors. This is advantageous since the measurement data can then be conducted by a plurality of expansion modules with sensors to form an evaluation unit. As a result, the modular design reduces the number of evaluation units, especially in larger systems to be monitored, thereby saving space. In this case, the evaluation units are particularly preferably configured in such a way that measurement data from a plurality of sensors of the same type can be detected and processed by the evaluation unit, whereby the measurement data of the sensors can be assigned to a respective location in one of the installations to be monitored. In this case, the smoke sensors and the temperature sensors are particularly preferably arranged in modules having a size of 2 TE.

Preferably, it is provided that the evaluation unit and the smoke chamber can be integrated within a common housing. Particularly preferably, this housing has a size of 3 TE. As a result, a particularly compact design is ensured, which is advantageous if the mounting space is limited for the smoke and thermal difference meter.

Fig. 1:

eine schematische Darstellung des Rauch- und Thermodifferenzmessers mit modularen Komponenten und

Fig. 2

eine schematische Darstellung des Rauch- und Thermodifferenzmessers mit im Gehäuse untergebrachten Komponenten und einer erweiterten Sensorik.

Further features, details and advantages of the invention will become apparent from the wording of the claims and from the following description of exemplary embodiments with reference to the drawings. Show it:

Fig. 1:

a schematic representation of the smoke and thermal difference meter with modular components and

Fig. 2

a schematic representation of the smoke and thermal difference meter with accommodated in the housing components and an expanded sensor.

FIG. 1 shows the smoke and thermal difference meter 1 with a smoke chamber 10, which has an inlet opening 20 and an outlet opening 25. The smoke-displaced air at a certain temperature flows from a space outside the smoke chamber 10 through the entrance opening 20 into the smoke chamber 10. The air is then passed along a flow path 110 through the smoke chamber 10 and exits the smoke chamber 10 through the outlet opening 25. The smoke-added air at a certain temperature can be generated for example by a fire and / or overheating of a monitored system 200. It is also conceivable that air is only provided with a certain temperature at an overheating. The smoke chamber 10 also has a smoke sensor 30, 35, which is formed by an infrared transmitting element 30 and an infrared receiver element 35. The smoke chamber 10 also has a temperature sensor 40. By means of the smoke sensor 30, 35 and the temperature sensor 40, the smoke concentration and the temperature of the air can be determined, which flows through the smoke chamber 10. In this case, the smoke sensor 30, 35 with its infrared transmitting element 30 and its infrared receiver element 35 uses the backscattering of infrared radiation of smoke particles. The temperature sensor 40 utilizes the resistance dependence of the temperature of materials such as metals such as platinum.

The smoke and thermal difference meter 1 furthermore has an evaluation unit 50, which is arranged outside the smoke chamber 10. To this evaluation unit 50, the measurement data of the sensors 30, 35 (smoke concentration) and 40 (temperature) are passed.

By means of the evaluation unit 50, the temperature and the smoke concentration can be detected, stored and processed. In particular, by the storage of the temperature data, a temperature increase of the examined air can be determined, thereby a thermal difference meter can be realized. By means of a thermal difference meter, temperature increases can be determined over certain periods of time. For this purpose, the temperature sensor 40 has a resolution with respect to the rate of temperature rise of preferably 3 K / s. The joint evaluation of the data of the smoke sensor 30, 35 and the temperature sensor 40 further increases the reliability of the smoke and thermal difference meter 1, since erroneous measurements due to the holistic view of the measured values of all available sensors 30, 35, 40 incorrect measurements of individual sensors 30, 35 , 40 are identifiable. Furthermore, by processing the data, a comparison with reference data or models for certain situations is possible, whereby specific hazardous situations can be detected by the smoke and thermal difference meter 1.

Figure 2 shows the arrangement of the components of an embodiment of the smoke and thermal difference meter 1 in a housing 100. The housing 100 has the smoke chamber 10, in which the temperature sensor 40 and the smoke sensor 30, 35 are arranged. The smoke sensor has an infrared transmission unit 30 and an infrared reception unit 35. Furthermore, a flow path 110 is formed between the inlet opening 20 and the outlet opening 25 of the smoke chamber. The inlet opening 20 and the outlet opening 25 of the smoke chamber 10 are arranged such that a flow path 110 can be formed between them, along which air can be conducted from a space outside the smoke chamber 10. The smoke and thermal difference meter 1 is arranged in the vicinity of the system 200 to be monitored, so that air is simultaneously in contact with the smoke and thermal difference meter 1 and the system 200 to be monitored. Preferably, the smoke and thermal difference meter 1 is arranged for this purpose above the system 200 to be monitored.

In addition, within the housing 100, the evaluation unit 50, a signal unit 60, an air flow measuring means 70, a power supply unit 80, a transmitter 90 and a potential-free contact 120 are arranged. The signal unit 60 and the potential-free contact 120 can be activated on the basis of an evaluation result of the evaluation unit 50. Thus, signals and circuits can be made depending on the evaluation result and thus the state of the system 200 to be monitored. The air flow measuring means 70 as an additional sensor within the flow path 110, ie within the smoke chamber 10, can make the evaluation result of the evaluation unit more reliable since the flow rate of the air can be used for the correction of the measured values of the smoke and temperature sensor 1.

The transmitter 90 can also be controlled by the evaluation unit 50. Here, the transmitter 90 may send a signal to a receiving unit (not shown) disposed outside the housing 100. In particular, this may be a third device which is suitable for processing the information of the evaluation unit 50.

In case of failure of an external power supply (not shown), the power supply unit 80 is the power of the evaluation unit 50, the signal unit 60 and the transmitter 90 with energy. In the event that the smoke sensor 30, 35 and the temperature sensor 40 are active sensors, the power supply unit 80 is also available for the sensors 30, 35 and 40 as a power supply. Thus, an uninterrupted operation of the smoke and thermal difference meter is guaranteed.

The housing of the smoke and thermal differential meter is designed as a standard housing for DIN rail mounting in control cabinets according to DIN 43880 or in distribution cabinets according to DIN EN 61439. Here, the size of the design of the smoke and thermal difference meter is at least 4 and at most 5 division units. The elements of the smoke and thermal difference meter described in this embodiment, namely the evaluation unit 50, the signal unit 60, the air flow measuring means 70, the power supply unit 80, the transmitter 90 and the potential-free contact 120 can be arranged within the housing 100. These elements may alternatively be embodied as individual modules, which are arranged either in combination or as individually in a respective housing. These housings can also be mounted on DIN rails. The housing size of these modules is at least 1 graduation unit.

The invention is not limited to one of the above-described embodiments, but can be modified in many ways.

All of the claims, the description and the drawings resulting features and advantages, including design details, spatial arrangements and method steps may be essential to the invention both in itself and in various combinations.

LIST OF REFERENCE NUMBERS

1

Smoke and thermal difference meter

10

smokebox

20

inlet opening

25

outlet opening

30

Infrared transmitting element

35

Infrared receiver element

40

temperature sensor

50

evaluation

60

signal unit

70

Air flow measuring equipment

80

Power supply unit

90

transmitter

100

casing

110

flow path

120

potential-free contact

200

plant to be monitored

Claims (15)

Smoke and thermal differential meter (1) having at least one smoke chamber (10) having at least one inlet opening (20) which is connected to at least one outlet opening (25) by a flow path (110), at least one smoke sensor (30, 35), - At least one temperature sensor (40) and an evaluation unit (50), wherein smoke and heated air from a system (200) to be monitored from the at least one inlet opening (20) through the smoke chamber (10) along the flow path (110) to the at least one outlet opening (25) is conductible, characterized in that the at least a smoke sensor (30, 35) and the at least one temperature sensor (40) record measured values within the smoke chamber (10) and the measured values of the at least one smoke sensor (30, 35) and the at least one temperature sensor (40) can be conducted to the evaluation unit (50) are. Smoke and thermal difference meter (1) according to claim 1, characterized in that it comprises at least one signal unit (60). Smoke and thermal differential meter (1) according to one of the preceding claims, characterized in that it comprises at least one air flow measuring means (70). Smoke and thermal difference meter (1) according to one of the preceding claims, characterized in that it comprises at least one transmitter (90). Smoke and thermal differential meter (1) according to one of the preceding claims, characterized in that it comprises a buffered power supply unit (80). Smoke and thermal difference meter (1) according to one of the preceding claims, characterized in that it comprises at least one potential-free contact (120). Smoke and thermal differential meter (1) according to one of the preceding claims, characterized in that the smoke chamber (10) is antistatic. Smoke and thermal difference meter (1) according to one of the preceding claims, characterized in that the at least one smoke sensor (30, 35) has an infrared transmitting element (30) and an infrared receiver element (35). Smoke and thermal differential meter (1) according to one of the preceding claims, characterized in that the measured values of the at least one smoke sensor (30, 35), the at least one temperature sensor (40) and / or the air flow measuring means (70) wirelessly or by cable to the Evaluation device (50) are transferable. Smoke and thermal difference meter (1) according to one of the preceding claims, characterized in that the at least one temperature sensor (40) has a measurement resolution by which a temperature change rate of 3 K / s can be determined. Smoke and thermal differential meter (1) according to at least one of claims 2 to 5, characterized in that the at least one signal unit (60), the at least one air flow measuring means (70), the at least one transmitter (90) and / or the power supply unit (80 ) are modularized. Smoke and thermal difference meter (1) according to one of the preceding claims, characterized in that measurement data of the at least one temperature sensor (40) and the at least one smoke sensor (30, 35) by the evaluation unit (50) measurement data can be registered and processed. Smoke and thermal difference meter (1) according to claim 2, characterized in that the signal unit (60) is designed as a piezo signal unit. Smoke and thermal differential meter (1) according to one of the preceding claims, characterized in that it can be arranged in an electrical standard distributor or an electrical distribution cabinet. Smoke and thermal differential meter (1) according to one of the preceding claims, characterized in that it comprises a housing (100) with a standard size for installation in standardized recordings.

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