TRIGGERING ELEMENT FOR A FIRE PROTECTION SYSTEM, FIRE PROTECTION ELEMENT EQUIPPED THEREWITH, AND METHOD FOR DETECTING THE TRIGGERING OF A FIRE PROTECTION ELEMENT

Description

[0001] The invention relates to a triggering element for a fire protection system with at least one bursting body. Furthermore, the invention relates to a fire protection element, for example a sprinkler head or a smoke vent flap with at least one such triggering element, a fire protection system with a plurality of fire protection elements, and a method for detecting the activation of a sprinkler head or a smoke vent flap.

[0002] Such a trigger element for sprinklers is known from DE 3808384 A1. The known trigger element consists of a bursting body in the form of a cylindrical tube, each end of which is fused to form a plug. The tube is filled with a liquid that expands when heated, causing the tube to burst. This opens the sprinkler valve, allowing extinguishing water to escape. Such sprinkler systems in larger buildings can have a variety of sprinkler heads.

[0003] These conventional sprinklers have the disadvantage that, in larger buildings, the location of the activation is often difficult to determine. This means that the fire department must first laboriously locate the source of the fire within the building before extinguishing efforts can begin. In the event of a false activation, significant amounts of water can escape and cause extensive damage before the location of the activation and the fact of a false activation are recognized. In the event of a false activation of a smoke vent, rainwater can enter unnoticed and cause building damage.

[0004] DE 2 336 682 A discloses a trigger element in the form of a bursting cartridge for fire-safe flaps of a fire protection device. The trigger element is equipped with an electrical conductor. The conductor is applied to the bursting cartridge as a thin metallic layer. This allows the integrity of the bursting cartridge to be determined from a current flow through the conductor.

[0005] Based on the prior art, the invention is therefore based on the object of specifying a fire protection system and its parts which enable a triggered element to be easily located.

[0006] The object is achieved according to the invention by a device according to claim 1, a sprinkler head or a smoke exhaust flap according to claim 9, a fire protection system according to claim 10 and a method according to claim 13. Advantageous developments of the invention can be found in the subclaims.

[0007] According to one embodiment of the invention, a triggering element for a fire protection element of a fire protection system is proposed, which triggering element has at least one bursting body. The fire protection element proposed according to the invention can be, for example, a smoke exhaust flap and / or a sprinkler head. In some embodiments of the invention, the triggering element can contain a bursting body, which can have a cylindrical basic shape with a cavity filled with a liquid. In addition to the liquid, an air or gas bubble can be present in the cavity, which can compensate for temperature-related volume fluctuations of the liquid below the triggering temperature. However, if a predeterminable temperature is exceeded, the liquid expands so greatly that the bursting body bursts and triggers the fire protection element.

[0008] The bursting body can be made of glass or plastic. In some embodiments of the invention, different bursting bodies can be provided, each with different triggering temperatures, in order to adapt the fire protection system or its fire protection elements to the conditions of their location.

[0009] According to the invention, it is now proposed to mechanically connect the bursting body to at least one optical fiber. In some embodiments of the invention, the optical fiber can be a single-mode fiber, a few-mode fiber, or a multi-mode fiber. In some embodiments of the invention, the optical fiber can be or contain a glass fiber. In other embodiments of the invention, the optical fiber can be or contain a polymer fiber. In some embodiments of the invention, optical fibers from telecommunications can be used, which are available in large quantities at low cost.

[0010] According to the invention, at least one predetermined breaking point is incorporated into the optical fiber. The predetermined breaking point ensures that the optical fiber is reliably destroyed when the bursting body bursts. This means that optical signals propagating in the optical fiber are no longer transmitted at this point. The absence of the optical signal can thus be recognized as a triggering of the fire protection system. If it is known which optical fiber is installed at which location, or if the triggering elements are coded in another way, the triggering location of the fire protection system can be reliably determined.

[0011] According to the invention, the optical waveguide comprises a core and a cladding surrounding the core, so that optical signals are totally reflected at the interface between the core and cladding. According to the invention, the at least one predetermined breaking point is introduced into the optical waveguide by damaging or weakening the cladding. This leaves the core and thus the optical properties of the optical waveguide unchanged. However, the pre-damage to the optical waveguide ensures that it is reliably destroyed when the bursting body bursts.

[0012] In some embodiments of the invention, such damage to the optical fiber leading to a predetermined breaking point can be achieved by mechanical processing, for example, by grinding. In other embodiments of the invention, the optical fiber can be chemically damaged, for example, by etching. In yet other embodiments of the invention, the predetermined breaking point can be created by laser material processing. Material processing with a focused short-pulse laser can be used for this purpose, in particular. By selecting the focus position, the pulse energy, the number of individual pulses, and the pulse shape, the desired damage to the optical fiber can be precisely controlled both locally and in terms of its extent.

[0013] In one embodiment of the invention, the optical fiber can be attached to the bursting body at least two times by means of adhesive or clamping. This ensures that when the bursting body bursts, sufficient mechanical stress is introduced into the optical fiber so that it is reliably destroyed at at least one predetermined breaking point. Furthermore, attachment by means of adhesive or clamping enables the retrofitting of already installed fire protection systems without the need for extensive re-installation of the fire protection system. Since gluing the optical fiber leaves the bursting body unchanged, recertification of the fire protection system or bursting body can be avoided. The fire protection system can perform all its previous functions unchanged and is expanded to include the function of local detection of the trigger point.

[0014] In some embodiments of the invention, the optical fiber can be in contact with the bursting body, at least in part. This increases the mechanical stress acting on the optical fiber when the bursting body bursts. On the other hand, there is a high probability that the optical fiber will be further damaged by shards or splinters from the bursting body. This can increase the detection probability and thus the reliability of the method proposed by the invention.

[0015] In some embodiments of the invention, the optical fiber can have between one and about ten predetermined breaking points over a length of about 5 mm to about 15 mm. The redundant introduction of a plurality of predetermined breaking points can ensure that the optical fiber is reliably destroyed when the bursting body bursts.

[0016] In some embodiments of the invention, a predetermined breaking point can run approximately perpendicular to the longitudinal direction of the optical fiber. If the optical fiber runs approximately parallel to the longitudinal direction of the bursting body of the trigger element, the latter will be reliably and completely severed at the predetermined breaking point.

[0017] In some embodiments of the invention, the optical waveguide can contain at least one fiber Bragg grating. The fiber Bragg grating contains a plurality of spatial regions or voxels, which are at least partially incorporated into the core of the optical waveguide and which have a refractive index that differs from the refractive index of the surrounding material of the core. The distance between adjacent spatial regions or voxels defines the grating constant of the fiber Bragg grating. Such a fiber Bragg grating has the effect of reflecting light of a predeterminable wavelength defined by the grating constant, while transmitting light of a different wavelength. The fiber Bragg grating can thus be used to reflect an optical signal coupled into the optical waveguide.This allows the transmitter and receiver of the optical signal to be arranged at one end of the optical fiber, thus reducing the complexity of the device according to the invention. If fiber Bragg gratings with different grating constants are used for trigger elements, sprinkler heads, or even exhaust flaps at different locations, different locations can be differentiated using wavelength division multiplexing. Alternatively or additionally, different locations can be differentiated by the propagation time of a pulsed optical signal. This further reduces complexity, as an optical fiber does not have to be run from every element of the fire protection system to the building's fire alarm control center. This offers installation advantages, particularly when renovating old buildings.

[0018] In some embodiments of the invention, the fiber Bragg grating can be a chirped fiber Bragg grating. In such a chirped fiber Bragg grating, the grating constant changes along the length of the fiber Bragg grating. This allows the fiber Bragg grating to reflect a wider wavelength range, enabling reliable reflection and thus reliable detection without false alarms, even in the event of thermal drift of the optical signal wavelengths.

[0019] In some embodiments of the invention, a plurality of optical fibers can be coupled to a central optical fiber via a fused coupler or another known 3 dB coupler. The number of optical fibers can be between 2 and about 35 or between about 2 and about 50. This allows all sprinkler or smoke vent dampers of a fire compartment or floor to be connected to the building's fire alarm system with a single central optical fiber.

[0020] In some embodiments of the invention, the central optical waveguide can be connected to a spectrometer at one end, for example in a fire alarm control panel. A spectrometer can be embodied as an integrated optical component, for example as an AWG. In some embodiments of the invention, the spectrometer can be integrated into the central optical waveguide by containing at least one chirped fiber Bragg grating at one end, which is configured to direct light onto an optoelectronic semiconductor component. In some embodiments of the invention, at least a portion of the chirped fiber Bragg grating can be provided with additional scattering centers. This eliminates the need for an external spectrometer. Instead, light is coupled out of the central optical waveguide laterally, i.e., approximately orthogonal to the longitudinal extent.Light of different wavelengths is imaged at different locations, allowing the use of a spatially resolving detector, such as a photodiode array or a CCD line sensor, to detect the light intensity at different wavelengths or wavelength ranges. If the various trigger elements are equipped with optical fibers with different fiber Bragg gratings, individual pixels or pixel groups of a CCD line sensor or individual diodes of a photodiode array can be directly assigned to a trigger element of the fire protection system to be monitored. In this way, the location of a sprinkler activation or the installation location of a smoke exhaust damper can be easily determined and visualized, for example, using a database or a conversion table.

[0021] The invention will be explained in more detail below with reference to figures without limiting the general inventive concept. Figure 1 shows a trigger element according to the present invention in longitudinal section. Figure 2 shows a cross-section through an optical fiber used according to the invention. Figure 3 shows a sprinkler head according to the invention. Figure 4 shows a fire protection system according to the invention. Figure 5 shows an example of a measurement signal obtained according to the invention without triggering a sprinkler. Figure 6 shows an example of a measurement signal obtained according to the invention after triggering three sprinklers.

[0022] Based on the Figure 1 An embodiment of a trigger element 1 for a fire protection system is explained. The trigger element can be used, for example, to trigger a sprinkler or a smoke exhaust flap in the event of a fire.

[0023] For this purpose, the trigger element 1 contains a bursting body 10, which can be made of glass or plastic, for example. The bursting body 10 has an approximately cylindrical basic shape, which comprises a first end 101 and an opposite second end 102. The cross-section of the bursting body 10 can be polygonal or, in particular, round. The bursting body 10 contains a cavity 13, which is filled with a liquid and optionally an air or gas bubble. When the bursting body 10 and the enclosed liquid are heated, the liquid expands and, with increasing internal pressure, generates mechanical stress on the material of the bursting body 10, which ultimately leads to the bursting of the bursting body 10 upon sufficient heating.The geometry of the bursting body 10 and / or the enclosed amount of liquid and / or the composition can be selected such that different bursting bodies with different triggering temperatures can be provided, so that, depending on the requirements of the fire protection system, different triggering temperatures can be selected for the elements combined in the fire protection system, such as sprinklers or smoke exhaust flaps.

[0024] The sprinkler or smoke vent flap is designed so that, for example, a spring-loaded or water-pressure-loaded valve is held in a closed position by the bursting body 10. After the bursting body 10 bursts, the valve opens, allowing extinguishing water to escape from a sprinkler head.

[0025] In conventional fire protection systems, the activation of a sprinkler can only be inadequately detected. If monitoring is provided at all, it usually detects the drop in pressure in the water line following the activation. This means that, particularly in large installations in larger buildings, the fire service is often unable to reach the source of the fire quickly because the location of the fire that caused the sprinkler to activate is unknown. In the event of a false activation of a sprinkler, escaping extinguishing water can often cause major damage, which is less severe the faster the sprinkler can be found and the water flow stopped. It is therefore desirable to monitor the activation elements of a fire protection system so that the activation can be quickly detected and the location of the activated activation element within a building can be quickly determined.

[0026] For this purpose, the invention proposes attaching an optical waveguide 2 to the bursting body 10. According to some embodiments, the invention proposes attaching the optical waveguide to the bursting body 10 by means of one or two adhesive bonds 3. Alternatively or additionally, a clamping device (not shown) can also be used to attach the optical waveguide 2 to the bursting body 10. In this case, the optical waveguide 2 can run along the longitudinal extent of the bursting body 10 and be attached in such a way that it at least partially rests against the bursting body 10 in at least a partial section 23. The optical waveguide 2 can be configured to reflect incoming light and throw it back in the direction of incidence. This can be achieved, for example, by a mirrored end or by a fiber Bragg grating. The end of the optical waveguide not shown in the figure can, for example, be guided to a fire alarm control panel.There, an optical signal can be coupled into the optical fiber 2 and reflected at the end located at the trigger element. As long as the reflected signal is detected in the fire alarm control panel, the trigger element is intact. If the bursting body 10 is destroyed, the optical fiber 2 is also damaged, so that the reflected signal is no longer detected in the fire alarm control panel. For this purpose, the optical fiber 2 contains at least one predetermined breaking point 25. In the illustrated embodiment, three predetermined breaking points 25a, 25b and 25c are shown. In some embodiments of the invention, the optical fiber 2 can have between one and approximately ten predetermined breaking points 25 over a length of approximately 5 mm to approximately 15 mm.

[0027] If each trigger element is provided with an optical fiber, the location of the respective trigger element or the sprinkler equipped with it can be determined from the respective associated optical fiber. If several optical fibers are coupled to a central optical fiber, as described below, the location of the respective trigger element can be determined by the propagation time of a pulsed optical signal. In other embodiments of the invention, fiber Bragg gratings of different trigger elements can have different grating constants. This results in a different wavelength range of a broadband optical signal being reflected in each case. Thus, different trigger elements can be differentiated from one another in wavelength division multiplexing.

[0028] Figure 2 shows the cross-section through an optical waveguide 2, as it can be used for the above invention. As can be seen from Figure 2As can be seen, the optical waveguide 2 has a core 21 and a cladding 22 surrounding the core. The core has a core diameter dk, which can be between approximately 5 µm and approximately 80 µm. The cladding has a cladding diameter dm, which can be between approximately 80 µm and approximately 250 µm.

[0029] Core 21 and cladding 22 can be made of glass or plastic. The core and cladding have different refractive indices, so that a signal propagating in the core 21 is totally reflected at the interface between the core and cladding and thus propagates along the optical waveguide 2.

[0030] As from Figure 2 As can be further seen, a predetermined breaking point 25 was created by material processing with a short-pulse laser. The short-pulse laser can have a pulse duration of less than 250 fs and / or a pulse energy of more than 500 nJ at a wavelength of approximately 800 nm.

[0031] The pulse repetition rate can be between approximately 50 MHz and approximately 120 MHz. The interaction of the material of the cladding 22 with the intense laser radiation causes damage to the cladding material and thus a reduction in the mechanical stability of the optical fiber 2. This creates a predetermined breaking point in the optical fiber 2. By selecting the focus position of the laser radiation used to create the predetermined breaking point 25, the position of the predetermined breaking point 25 can be precisely controlled. Figure 2 shows, the predetermined breaking point 25 is located exclusively in the cladding 22, so that the optical properties for the optical signals propagating in the core 21 remain unaffected.

[0032] In the same way as described above for a predetermined breaking point 25, fiber Bragg gratings can be generated in the core 21 by point-to-point exposure of individual spatial regions or voxels.

[0033] Based on the Figure 3 A sprinkler head according to the present invention is explained. The sprinkler head 4 has a thread 41 at one end, with which it can be connected to a pipeline. An extinguishing agent, for example, water, flows through the pipeline to the sprinkler head.

[0034] The sprinkler head 4 has a Figure 3 invisible valve, which keeps the sprinkler head 4 closed during normal operation and thus prevents water from escaping. The valve of the sprinkler head 4 is kept closed by a trigger element 1, which is activated by the above-described Figure 1explained in more detail. The trigger element 1 is clamped to the sprinkler head 4 by a bracket 45 so that it can exert a closing force on the valve. An optional disc 42 can be arranged at the end of the bracket 45, which distributes the escaping extinguishing agent when the sprinkler head 4 is operated. If the sprinkler head is exposed to a strong heat source, for example due to a fire, the trigger element 1 is destroyed, as described above. This releases the flow of extinguishing agent so that the fire can be extinguished shortly after it starts and the fire is prevented from spreading.

[0035] Simultaneously with the destruction of the trigger element 1, the optical fiber 2, which runs parallel at least in sections, is destroyed, so that the triggering of the sprinkler head 4 can be registered in a fire alarm control center of the building.

[0036] Figure 4shows a fire protection system 6 with a plurality of sprinkler heads and / or smoke exhaust dampers. For reasons of clarity, Figure 4 Only the bursting bodies 10 of two such sprinkler heads or smoke vents are shown. In some embodiments of the invention, between about two and about 35 bursting bodies 10, each with associated optical fibers 2, may be present.

[0037] The optical fibers 2 are coupled to a central optical fiber 29 via a 3 dB coupler, for example, a fused coupler 28. The central optical fiber 29 runs from a fire alarm control panel to the last sprinkler to be monitored in the fire protection system 6. The 3 dB couplers 28 represent branch elements to which optical signals can be routed to the respective optical fiber 2.

[0038] How Figure 4As further explained, the fire protection system contains at least one light source 6. The light source 6 can, for example, be an LED, a semiconductor laser, a superluminescent diode, or another known light source. The light from the light source 6 is coupled into the central optical waveguide 29 and propagates along its longitudinal extent. At the 3 dB couplers 28, a portion of the light intensity propagating in the central optical waveguide 29 is transferred into the optical waveguide 2. The light propagates further in the optical waveguide 2 to the respective fiber Bragg grating 23 present there.

[0039] As in Figure 4As shown schematically, the fiber Bragg grating 23a of the first optical waveguide 2 has a different grating constant than the second fiber Bragg grating 23b of the second optical waveguide 2. As a result, a different wavelength or a different wavelength range is reflected at the fiber Bragg gratings 23a and 23b. The reflected portion is thrown back in the direction of incidence in the optical waveguide 2. The transmitted portion can leave the optical waveguide 2 and be radiated into the environment.

[0040] The portion of the light reflected by the fiber Bragg grating 23 is redirected via the 3 dB coupler 28 into the central optical waveguide 29 and thus reaches a longitudinal section in which a chirped fiber Bragg grating 27 is arranged. This fiber Bragg grating 27 causes the light to be coupled out laterally of the central optical waveguide 29, with light of a first wavelength λ 1 interfering at a different location than light of a different wavelength λ n . An optoelectronic semiconductor component 5 serves for the spatially resolved reception of the optical signals, for example, by a photodiode array, a CCD line sensor, or a CMOS sensor. Thus, the position of the optical waveguide 2, and thus of the respective sprinkler head 4, within the building can be deduced from the respective measurement location on the optoelectronic semiconductor component 5.

[0041] If a multi-mode fiber with a core diameter of approximately 60 µm is used as the central optical fiber 29, 32 or more measuring points or sprinkler heads 4 can be easily read out using a single central optical fiber 29. In this case, there would be a dynamic difference of 22.5 dB between the first and the thirty-second measuring point along the longitudinal extent of the central optical fiber 29. This dynamic range can be easily read out using conventional CCD line sensors, which offer a dynamic range of approximately 48 dB. To further increase sensitivity, the integration time of the optoelectronic semiconductor component 5 can be between approximately 0.1 second and approximately 5 seconds or between approximately 1 second and approximately 5 seconds.

[0042] It should be noted that the fire protection system is in accordance with Figure 4is to be understood merely as an example. Of course, instead of the chirped fiber Bragg grating 27, another spectrometer can be used, for example an AWG or another known design.

[0043] Even if the light source 6 in Figure 4 at the opposite end of the central optical waveguide 29, it is of course known to those skilled in the art that the spectrometer or the chirped fiber Bragg grating 27 and the light source 6 can also be arranged at one and the same end of the central optical waveguide 29. This can reduce the complexity of the fire protection system and increase operational safety.

[0044] Based on the Figures 5 and 6 The functioning of the fire protection system is Figure 4explained. The signal intensity is shown on the ordinate and the number of the respective sprinkler on the abscissa. Each sprinkler is coded by a fiber Bragg grating 23, as described above. The reflection maximum of each fiber Bragg grating can have a half-width of approximately 0.5 nm and differ from the reflection maximum of other, particularly neighboring, fiber Bragg gratings. Thus, the position of the sprinkler can be directly deduced from the measurement location on the optoelectronic semiconductor component 5 behind the spectrometer.

[0045] Figure 5 shows a fully functional fire protection system before its activation. It can be seen that for each of the 26 sprinklers installed in the building, a reflection maximum was obtained, as shown above with the Figure 4explained. Due to the signal attenuation along the central optical fiber 29, the intensity decreases with increasing distance from the fire alarm control panel.

[0046] Figure 6 shows the same measurement after sprinklers 6, 11, and 23 have been triggered, for example, due to a fire or a false trigger. Triggering occurs when bursting body 10 bursts, which also destroys the respective associated fiber optic cables 2 at at least one predetermined breaking point 25. This results in no more light being supplied to the respective fiber Bragg grating 23, and no reflection peak can be measured. The triggering of the sprinklers can thus be easily detected by setting a trigger threshold, which can also be selected relatively close to the zero line, thus enabling reliable detection without unnecessary false alarms.

[0047] Of course, the invention is not limited to the illustrated embodiments. The above description is therefore not to be considered limiting, but rather illustrative. The following claims are to be understood as meaning that a stated feature is present in at least one embodiment of the invention. This does not exclude the presence of further features. Where the claims and the above description define "first" and "second" embodiments, this designation serves to distinguish between two similar embodiments without establishing a priority.

Claims

1. Triggering element (1) for a fire protection system, comprising at least one rupture body (10), characterized in that the rupture body (10) is provided with an optical waveguide (2) which has a core (21) and a cladding (22) surrounding the core and into which optical waveguide at least one predetermined breaking point (25) is introduced which was produced by weakening the cladding.

2. Triggering element according to claim 1, characterized in that the rupture body (10) is made of glass or plastic material and / or in that the rupture body (10) is made as a hollow body and is at least partially filled with a liquid.

3. Triggering element according to any one of claims 1 to 2, characterized in that the optical waveguide (2) is attached to the rupture body (10) by means of adhesive bonding (3) or clamping at least at two points (11, 12) and / or in that the optical waveguide (2) rests against the rupture body (10) at least in one segment (23).

4. Triggering element according to any one of claims 1 to 3, characterized in that the optical waveguide (2) has between one and about ten predetermined breaking points (25) over a length of about 5 mm to about 15 mm.

5. Triggering element according to any one of claims 1 to 4, characterized in that the predetermined breaking point (25) has been obtained by mechanical processing or in that the predetermined breaking point (25) has been obtained by etching.

6. Triggering element according to any one of claims 1 to 5, characterized in that the predetermined breaking point (25) can be obtained by irradiating the cladding (22) by means of a short-pulse laser and / or in that the predetermined breaking point (25) runs approximately perpendicular to the longitudinal direction of the optical waveguide (2).

7. Triggering element according to any one of claims 1 to 6, characterized in that the optical waveguide (2) contains at least one fiber Bragg grating (23).

8. Triggering element according to claim 7, characterized in that the fiber Bragg grating (23) is a chirped fiber Bragg grating (23).

9. Sprinkler head (4) or smoke exhaust flap comprising at least one triggering element according to any one of claims 1 to 8.

10. Fire protection system (6) comprising a plurality of sprinkler heads and / or smoke exhaust flaps according to claim 9.

11. Fire protection system according to claim 10, characterized in that a plurality of optical waveguides (2) are coupled to a central optical waveguide (29) via a respective 3dB coupler (28) or in that between about 2 and about 35 optical waveguides (2) are coupled to a central optical waveguide (29) via a respective 3dB coupler (28).

12. Fire protection system according to any one of claims 10 or 11, characterized in that the central optical waveguide (29) is connected at one end to a spectrometer or contains a spectrometer.

13. Method for detecting the triggering of a sprinkler head or of a smoke exhaust flap of a fire protection system with a triggering element (1) having at least one rupture body (10), characterized in that the rupture body (10) is provided with an optical waveguide (2) which has a core (21) and a cladding (22) surrounding the core, and at least one predetermined breaking point (25), which was produced by weakening part of the cladding, is introduced into the optical waveguide (2), and the breaking of the optical waveguide (2) is detected.

14. Method according to claim 13, characterized in that light from an LED or a superluminescent diode or a semiconductor laser is coupled into the optical waveguide (2) to generate an optical signal and the optical signal transmitted through the optical waveguide is detected, and / or in that the optical waveguide (2) contains at least one fiber Bragg grating (23) and the triggering of a triggering element (1) from a plurality of triggering elements (1) of a fire protection system is detected by wavelength multiplexing and / or the propagation time of the optical signal.

15. Method according to any one of claims 13 to 14, characterized in that the location, at which the triggering of a sprinkler head or of a smoke exhaust flap has been detected, is visualized in a site plan.