DE202019001963U1 - Point detector, in particular fire or smoke detector, with at least one thermally decoupled on an associated circuit substrate arranged temperature sensor - Google Patents

Abstract

Point detector with a detector housing (11) and a circuit carrier (2) accommodated therein, wherein a plurality of components, at least one temperature sensor (3) and an evaluation unit are arranged on the circuit carrier (2), the evaluation unit for detecting and evaluating an ambient temperature in the Is provided in the circuit carrier (2) at least one of the temperature sensor (3) adjacent recess (4) such that the temperature sensor (3) only via one or more a plurality of remaining webs (5) remains connected to the circuit carrier (2) in order to largely decouple the temperature sensor (3) thermally from the circuit carrier (2).

Description

The invention relates to a point detector with a detector housing and a circuit carrier received therein. On the circuit carrier a plurality of components, at least one temperature sensor and an evaluation unit are arranged. The latter is intended for the detection and evaluation of an ambient temperature in the area of the point detector and for the output of a temperature information derived therefrom. The point detector is in particular a fire or smoke detector, a temperature, heat or heat detector, or a combination thereof.

The considered point detectors are also referred to as danger detectors. The point detectors may be provided for detecting an ambient temperature, e.g. to detect the heat generated in a fire or fire and / or to regulate the room temperature in the sense of a room climate control. Alternatively or additionally, the point detectors may also be fire detectors or smoke detectors. For this purpose, they have a detection unit for the detection of smoke particles. The detection unit may e.g. have an open measuring chamber or a closed measuring chamber for smoke detection. Consequently, such a fire or smoke detector is also referred to as a closed or open fire or smoke detector. Furthermore, these fire or smoke detectors can be optical fire or smoke detectors, which have an optical detector unit for detecting smoke particles which works according to the scattering principle. Alternatively or additionally, they may comprise a detector unit operating according to the acoustooptic principle and / or one or more gas sensors for detecting flammable gases.

The considered point detectors can be connected via a common detector line, in particular via a two-wire line, signal and / or data technology with a fire alarm panel. Several fire alarms of this type may be connected in detector zones or detector lines to a fire alarm control panel, via which the electrical supply of the fire detectors is typically also supplied with power. Alternatively or additionally, the point detectors can be "wireless". In this case, the point detectors communicate wirelessly, e.g. via radio, with the fire alarm panel and / or with neighboring further point detectors.

Based on the above-mentioned prior art, it is an object of the invention to provide a point detector, in particular a fire or smoke detector, which allows a faster temperature detection.

These objects are achieved by the subject matter of the independent claims. Advantageous embodiments of the present invention are described in the dependent claims.

According to the invention, at least one recess adjoining the temperature sensor is provided in the circuit carrier in such a way that the temperature sensor only remains connected to the circuit carrier via one or more remaining bars in the circuit carrier in order to decouple the temperature sensor thermally from the circuit carrier.

By a large extent, it is meant that only a fraction of the heat introduced or discharged from the outside into the temperature sensor is coupled into the temperature sensor via heat conduction via the circuit carrier. The fraction is less than 5 percent, especially less than one percent. Preferably, the temperature sensor is connected via two remaining webs to the rest of the circuit carrier.

Due to the extensive thermal decoupling of the temperature sensor, a faster temperature detection of the surrounding air temperature sensor is possible.

So far, the heat capacity of the circuit substrate with application of the temperature sensor on a continuous circuit carrier by appropriate heat input or heat removal adversely thermally compensated. This ultimately caused a slower, that is slower temperature detection. Small and rapid changes in the air temperature are therefore not sufficiently quickly detectable by this balancing thermal coupling effect.

In one embodiment, a plurality of temperature sensors are mounted on the circuit carrier. At least one adjacent recess to the circuit carrier for thermal decoupling is present at least in some of the temperature sensors. As a result, an average temperature detection of the surrounding air temperature and a redundant temperature detection are advantageously possible.

According to a further embodiment, the respective adjoining, at least one recess is an opening passing through the circuit carrier or not completely passing through in the sense of a blind hole. The respective through recess may e.g. are introduced by means of drilling or punching, the not completely penetrating through recess, e.g. by milling.

The circuit carrier preferably has a uniform circuit carrier thickness. It has the respective at least one remaining web on the circuit substrate thickness preferably uniformly reduced web thickness.

The circuit carrier is typically a single, two or more layer printed circuit board or board. It usually has a thickness in the range of 0.3 to 1 mm. The reduction of the web thickness can e.g. be effected by milling. The web thickness can be reduced from only one circuit carrier side or from both sides. In particular, there remains a reduced web thickness, which is at least 20 percent of the original circuit substrate thickness. In addition, the reduced web thickness is selected such that the temperature sensor is "mechanically suspended" in the intended use of the point detector in or on the remaining circuit board.

It is advantageous if, according to a further embodiment, the circuit carrier additionally has a reduced carrier thickness in a region on which the respective temperature sensor is mounted. As a result, the thermal heat capacity in the region of the temperature sensor is advantageously further reduced. For this purpose, the circuit carrier area between the terminal contacts of the temperature sensor can be reduced in its carrier thickness, such. by introducing a blind hole by milling or drilling.

According to one embodiment, the respective temperature sensor has at least two connection contacts, wherein the respective connection contacts are in each case electrically contacted with a conductor track and / or in the circuit carrier. The contacted printed conductors are led further into the circuit carrier via the at least one remaining web. The temperature sensor may e.g. be an integrated component having three terminals, wherein two terminals are provided for the positive and negative supply voltage and wherein the third terminal contact is provided for outputting a temperature signal. It can also have only two connection contacts in the sense of a temperature-dependent current or voltage source.

According to a particularly advantageous embodiment, the respective temperature sensor is a temperature-dependent resistor. It is designed in particular as an SMD component. The temperature-dependent resistor is preferably a so-called PTC (for "Positive Temperature Coefficient") or a so-called NTC (for "Negative Temperature Coefficient"), ie a resistor with a positive or negative temperature coefficient. Such components have a very compact compact design.

According to a preferred embodiment, a respective temperature sensor is in the detector housing 3 opposite arranged housing opening available. As a result, a particularly rapid temperature detection of the prevailing in the environment of the point detector ambient temperature is possible.

According to a further embodiment, the temperature sensors are preferably distributed uniformly in a region of the outer edge of the circuit carrier in the circumferential direction of the outer edge. By means of the electronic evaluation unit, a value for a mean ambient temperature can be determined from the respective individual ambient temperatures detected by the temperature sensors. The value for the determined average ambient temperature, e.g. a Celsius value, may then be output to a central office connected to the point detector as a temperature information value, such as a temperature value. by radio.

According to a particularly advantageous embodiment, the circuit carrier is at least partially rotationally symmetrical. It is preferably an even number of a plurality of temperature sensors in a region of the outer edge of the circuit substrate distributed uniformly in the circumferential direction of the outer edge. There are two opposing temperature sensors connected in series. The respective series circuits are part of a temperature measuring bridge circuit. A value for a mean ambient temperature can be determined from the temperature measuring voltages applied to the respective center taps of the series circuits. Finally, it is possible to determine direction information and / or a measure of an airflow present in the vicinity of the point detector from the difference between the respective temperature measuring voltage and the averaged ambient temperature.

The investigations can be carried out, for example, by an electronic evaluation unit. Alternatively, it can be decentralized, such as via an external central office connected to the point detector. The determined directional information can be used to determine, for example, whether there is a draft or an air flow in the area of the point detector. If such or such a too high speed value, so this may be an indication that under these flow conditions no reliable detection of smoke and fumes more is possible. By determining the direction information, it is possible, for example, to determine air flows through open windows or doors. This can be automated closing the windows and Doors are made to avoid, for example, health impairment of people present or to report automatically in the event of fire, the present of fire-accelerating acting air currents to the control panel. On the basis of the determined directional information for the detected air flow, the location of the source of the air flow can also be determined, in particular in combination with a large number of such point detectors according to the invention, which are jointly connected to a data center. The latter can be configured to computationally determine the total air flow profile, for example within a building, from the multiplicity of direction information received for the air flows and from their respective dimensions.

The object of the invention is further achieved with a temperature, heat or heat detector, designed as a point detector with the novel thermal decoupling of the at least one temperature sensor on the circuit carrier.

Finally, the object of the invention is achieved by a smoke or fire detector, designed as a point detector with the inventive thermal decoupling of the at least one temperature sensor on the circuit carrier. The smoke or fire detector has a detection unit for the detection of smoke particles.

• 1 einen Punktmelder am Beispiel eines Brandmelders mit mehreren Temperatursensoren,
• 2 ein Beispiel für einen Schaltungsträger in einem Punktmelder mit dort eingebrachten Ausnehmungen, angrenzend an mehrere Temperatursensoren, und mit verringerter Stegdicke gemäss der Erfindung,
• 3 eine vergrösserte Ansicht eines Bereichs des Schaltungsträgers mit einem dort applizierten Temperatursensor gemäss 2,
• 4 eine Schnittdarstellung durch den Schaltungsträger gemäss 3 entlang der eingetragenen Schnittlinie IV-IV,
• 5 eine alternative Realisierung der Reduzierung der Stegdicke,
• 6 ein Beispiel für eine einseitige Aufhängung eines Temperatursensors im oder am Schaltungsträger,
• 7 ein Schnittdarstellung durch den Schaltungsträger gemäss 2 entlang der eingetragenen Schnittlinie VII-VII, und
• 8 eine Messbrücke für die Erfassung einer Richtungsinformation für Luftströmungen im Bereich des Punktmelders.

The invention and advantageous embodiments of the present invention will be explained using the example of the following figures. Showing:

• 1 a point detector using the example of a fire detector with several temperature sensors,
• 2 an example of a circuit carrier in a point detector with recesses introduced there, adjacent to a plurality of temperature sensors, and with reduced web thickness according to the invention,
• 3 an enlarged view of a portion of the circuit substrate with a there applied temperature sensor according to 2 .
• 4 a sectional view through the circuit carrier according to 3 along the registered section line IV-IV,
• 5 an alternative realization of the reduction of the web thickness,
• 6 an example of a one-sided suspension of a temperature sensor in or on the circuit board,
• 7 a sectional view through the circuit carrier according to 2 along the registered section line VII-VII, and
• 8th a measuring bridge for the detection of a direction information for air currents in the area of the point detector.

1 shows a point detector 1 using the example of a fire detector with several temperature sensors 3 , With the reference number 11 is a detector housing and with the reference numeral 2 a circuit carrier, such as a printed circuit board, incorporated therein. On this circuit board 2 typically a plurality of components, such as resistors, capacitors and semiconductor devices are arranged. For clarity, a graphic representation has been omitted. The same applies to a typically required electronic evaluation unit in an integrated form, such as for a microcontroller. On the other hand, you can see several temperature sensors 3 for temperature detection in the form of SMD components. The evaluation unit is for detecting and evaluating an ambient temperature in the area of the point detector 1 and for outputting a temperature information derived therefrom. With the reference number 12 Furthermore housing openings are designated by the smoke to be detected to an inner closed optical measuring chamber 13 can get. By means of temperature sensors 3 In addition, the temperature of the penetrating smoke is detected.

2 shows an example of a circuit carrier 2 in a point detector 1 with recesses introduced there 4 , adjacent to several temperature sensors 3 , and with reduced web thickness S according to the invention. In the example of 2 has the circuit carrier 2 a partially rotationally symmetric, hexagonal, point-symmetrical design. It may alternatively have a circular shape or another polygonal configuration, such as square. The circuit carrier 2 is typically a single, dual or multi-layer printed circuit board with a uniform circuit substrate thickness. For reasons of clarity, it was once again based on the graphic representation of the on the circuit carrier 2 otherwise existing components omitted. Only eight are shown on the outer edge of the circuit carrier 2 arranged temperature sensors 3 , a centrally located, double-sided temperature sensor 3 and another, arranged in the intermediate region, one-sided suspended temperature sensor 3 , each in the form of a temperature-dependent SMD resistor.

According to the invention is now in the circuit carrier 2 one to the temperature sensor 3 adjacent recess 4 provided such that the temperature sensor 3 only one or more remaining bridges 5 with the circuit carrier 2 remains connected to the temperature sensor 3 largely thermally from the circuit carrier 2 to decouple.

The (directly) on the outer edge of the circuit board 2 arranged temperature sensors 3 are on the one hand in the sense of an adjacent recess through the open environment, that is by the over the outer edge of the circuit substrate 2 outgoing range, thermally decoupled. On the other hand, they are each by such in the immediate vicinity of the temperature sensor 3 arranged recess 4 from the circuit carrier 2 thermally decoupled, so only two bars 5 remains to a circuit carrier piece on which the respective temperature sensor 3 is applied. In the present example, the recess 4 an elongated, continuous opening in the form of a long hole. The circuit carrier piece is generally only slightly larger in size than the component itself to be supported.

The exemplary centrally arranged temperature sensor 3 is of two semi-circular, continuous recesses 4 surrounded, separated only by two remaining webs 5 in the circuit carrier 2 over which the temperature sensor 3 still hung on both sides. The electrical connection lines from the temperature sensor 3 to the circuit carrier 2 are realized as tracks, which pass over one of the two bridges 5 or distributed over both bridges 5 run.

The example in the area between the center and outer edge of the circuit substrate 3 arranged another temperature sensor 3 is even suspended only on one side, surrounded by a nearly circular recess 4 for thermal decoupling of the temperature sensor 3 from the adjacent circuit carrier 2 , The electrical connection lines from the temperature sensor 3 to the circuit carrier 2 are realized in this case as interconnects, which over the one remaining web 5 run.

3 shows an enlarged view of a portion of the circuit substrate 2 with a temperature sensor applied there 3 according to 2 , The temperature sensor shown 3 , here in the form of a temperature-dependent SMD component, has two connection contacts 30 on. Both connection contacts 30 are with a corresponding, on the top of the printed circuit board shown 2 trained contacting surface 21 soldered. With the reference number 23 is the lot and with 24 denotes an insulating surface. The latter typically has no metallization at the top of the circuit board 2 on. Furthermore, both contacting surfaces 24 via one implementation contact each 22 with the underside of the circuit board 2 connected. From there each runs a connecting line 7 in the form of a "printed" trace further to the rest, not shown part of the circuit board 2 for metrological detection of the temperature-dependent change in resistance, such as by means of an A / D converter.

Furthermore, the two remaining webs 5 According to the invention, a preferably uniformly reduced web thickness compared to the (uniform) circuit substrate thickness S on. This reduces the thermal heat capacity of the temperature sensor on the one hand 3 surrounding circuit board material. On the other hand, the heat input or heat discharge from the adjacent printed circuit board area through the reduced web cross-section through into the printed circuit board piece with the applied temperature sensor 3 reduced. The two introduced recesses 6 are preferably cutouts.

4 shows a sectional view through the circuit carrier 2 according to 3 along the registered section line IV-IV. In this illustration, the reduction of the printed circuit board thickness is particularly good D on the web thickness S recognizable. The reduction lies in the present 4 exemplarily at about 60%. In addition, there is also the remaining PCB piece on which the temperature sensor 3 is applied to a carrier thickness T reduced. In the present example, the reduction is in the form of a depression 8th at about 50%. The depression 8th can be a cutout on the underside of the printed circuit board piece, as shown in the present example. The depression 8th can also, as in the following 5 shown on top of the printed circuit board piece in the area of the insulating surface 24 be introduced.

5 shows an alternative realization of reducing the web thickness S , In this case, the reduction takes place from both outer sides of the circuit board 2 that means from the top and from the bottom. At the same time is the circuit board 3 a multi-layer printed circuit board whose middle position for the continuation of the connecting lines 7 from the temperature sensor 3 to the remaining circuit board 2 is used.

6 shows an example of a one-sided suspension of a temperature sensor 3 in or on the circuit carrier 2 according to the example according to 2 , In the present example is also the bridge 5 reduced in its web thickness.

7 shows a sectional view through the circuit carrier 2 a point detector 1 according to 2 along the registered section line VII-VII. The circuit carrier 2 is in a detector housing 11 of the point detector 1 accommodated. According to the invention, the respective temperature sensor 3 one in the detector housing 11 opposite arranged housing opening OF available. As a result, the temperature detection is very fast. It is advantageous for a largely direction-independent temperature detection, if the multiple on the circuit carrier 2 radially outside temperature sensors 3 one each in the detector housing 11 radially outside housing opening OF is available.

8th shows a measuring bridge for the detection of a direction information for air currents in the area of the point detector 1 , Prerequisite is that the circuit carrier 2 on the one hand is essentially rotationally symmetrical and on the other hand that, as in 2 shown several temperature sensors 3 in a region of the outer edge of the circuit carrier 2 are preferably distributed uniformly in the circumferential direction of the outer edge. There are two opposing temperature sensors 31 . 35 ; 32 . 36 ; 33 . 37 ; 34 . 38 connected in series. At the center taps each provided for metrological evaluation temperature measurement voltage U d1-UD4 on. These can then be detected, for example, via an A / D converter with a corresponding number of analog measuring inputs. Furthermore, a first half of temperature sensors 31 . 36 - 38 together via a series resistor Rv to a positive supply voltage V + switched while the second half of the temperature sensors 32 - 35 is connected to a negative supply voltage. In the present example, the negative supply voltage is the ground. With uv is a bias voltage, which can be used, for example, to a constant measuring current through the series resistor Rv memorize.

By suitable evaluation, such as by means of a suitably programmed microcontroller, then a value for a mean ambient temperature from the voltage applied to the respective center taps of the series circuits temperature measuring voltages U d1-UD4 determined. In addition, directional information and / or a measure of one in the vicinity of the point detector 1 present air flow from the difference of the respective temperature measurement voltage U d1-UD4 can be determined to the average ambient temperature.

LIST OF REFERENCE NUMBERS

1

Point detectors, fire detectors, heat detectors

2

Circuit carrier, circuit board, circuit board

3,

Temperature sensor, temperature-dependent resistance,

31-38

NTC, PTC, SMD components

4

Recess, bore, opening

5

Bridge, printed circuit board bridge

6

Recess, cutout

7

conductor path

8th

deepening

11

detector housing

21

contacting surface

22

Implementation contact, Via

23

solder

24

isolation area

30

terminals

D

Circuit substrate thickness

OF

housing opening

S

web thickness

T

carrier thickness

Rv

dropping resistor

V +

supply voltage

U d1-UD4

Temperature measuring voltages

uv

preload

Claims (13)

Point detector with a detector housing (11) and a circuit carrier (2) accommodated therein, wherein a plurality of components, at least one temperature sensor (3) and an evaluation unit are arranged on the circuit carrier (2), the evaluation unit for detecting and evaluating an ambient temperature in the region of the point detector and is provided for outputting a derived temperature information, characterized in that the circuit carrier (2) at least one of the temperature sensor (3) adjoining the recess (4) is provided such that the temperature sensor (3) only through one or a plurality of remaining webs (5) remains connected to the circuit carrier (2) in order to largely decouple the temperature sensor (3) thermally from the circuit carrier (2). Point detector after Claim 1 , wherein a plurality of temperature sensors (3) on the circuit substrate (2) are mounted and wherein at least a portion of the temperature sensors (3) each have at least one adjacent recess (4) to the circuit carrier (2) for thermal decoupling is present. Point detector after Claim 1 or 2 wherein the respective adjacent, at least one recess (4) is an opening passing through the circuit carrier (2) or not completely passing therethrough. Point detector according to one of the preceding claims, wherein the circuit carrier (2) has a uniform circuit substrate thickness (D) and wherein the respective at least one remaining web (5) has a relation to the circuit substrate thickness (D) preferably uniformly reduced web thickness (S). Point detector according to one of the preceding claims, wherein the circuit carrier (2) in a region on which the respective temperature sensor (3) is mounted, a reduced carrier thickness (T). Point detector according to one of the preceding claims, wherein the respective temperature sensor (3) has at least two connection contacts (30), wherein the respective connection contacts (30) are each electrically contacted with a conductor track (7) on and / or in the circuit carrier (2) and wherein the contacted conductor tracks (7) via one or both remaining webs (5) in the circuit carrier (2) are continued. Point detector according to one of the preceding claims, wherein the respective temperature sensor (3) is a temperature-dependent resistor, in particular an SMD component. Point detector according to one of the preceding claims, wherein in the detector housing (11) in each case one of the temperature sensor (3) arranged opposite housing opening (OF) is present. Point detector according to one of the preceding claims, wherein the circuit carrier (2) is a one-, two- or multi-layer printed circuit board. Point detector according to one of the Claims 2 to 9 , wherein the temperature sensors (3) in a region of the outer edge of the circuit substrate (2) are arranged distributed uniformly in the circumferential direction of the outer edge and wherein by means of the electronic evaluation unit, a value for a mean ambient temperature from the respective individual ambient temperatures detected by the temperature sensors (3) can be determined. Point detector according to one of the Claims 2 to 9 - Wherein the circuit carrier (2) is at least partially rotationally symmetrical, - where an even number of several temperature sensors (3) in a region of the outer edge of the circuit substrate (2) are arranged uniformly distributed in the circumferential direction of the outer edge, - wherein each two themselves opposite temperature sensors (3, 31, 35, 32, 36, 33, 37, 34, 38) are connected in series, wherein the respective series circuits are part of a temperature measuring bridge circuit, wherein a value for an average ambient temperature from the at wherein a directional information and / or a measure of an existing in the environment of the point detector air flow from the difference of the respective temperature measuring voltage (Ud1-Ud4) to the average ambient temperature can be determined. Temperature, heat or heat detector (1), designed as a point detector according to one of the preceding claims. Smoke or fire detector (1), designed as a point detector according to one of the preceding claims, wherein the smoke or fire detector has a detection unit for the detection of smoke particles.

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