Gas extinguishing system

Abstract

The present invention relates to a gas extinguishing system for a predefined protected area, particularly small-parts storage systems, wherein the gas extinguishing system comprises an inert gas source and a diffuser system fluidly connected to the inert gas source by a tubing system. The diffuser system comprises a diffuser tube having a plurality of drill holes provided in the surface of the diffuser tube and a pressure reducer allocated to the diffuser tube. In order to be able to achieve non-interactiveness with respect to the diffuser system from the standpoint of the design of the gas extinguishing system, the inventive provides for designing the diffuser system such that a primary baffle pressure measured in absolute bar is at least twice as high as the internal pressure of the diffuser tube during the flooding period dimensioned for the protected area and that the internal pressure of the diffuser tube during the dimensioned flooding period is at a maximum of 2 bar absolute.

Claims

1. A gas extinguishing system for a predefined protected area, wherein the gas extinguishing system comprises: an inert gas source, designed to provide inert gas at least during a flooding period dimensioned for the protected area; and a diffuser system fluidly connected or connectable to the inert gas source by a tubing system, wherein the diffuser system includes: at least one diffuser tube having a plurality of drill holes provided in a surface of the diffuser tube through which at least a portion of the inert gas provided by the inert gas source is introduced radially into the protected area relative to a longitudinal direction of the diffuser tube; and a pressure reducer allocated to the at least one diffuser tube including a baffle, wherein the pressure reducer is fluidly disposed between the tubing system and the at least one diffuser tube and separates the tubing system, which is at a maximum of 60 bar, from the diffuser tube defining a low-pressure area relative to the tubing system, the diffuser system operating with a primary baffle pressure, associated with the baffle, measured in absolute bar that is at least twice as high as an internal pressure of the diffuser tube during the flooding period, and the diffuser system operating with the internal pressure of the diffuser tube during the flooding period amounts to a maximum of 2 bar absolute.

2. The gas extinguishing system according to claim 1, wherein a same mass flow of inert gas is discharged from the drill holes formed in the surface of the at least one diffuser tube during the flooding period.

3. The gas extinguishing system according to claim 1, wherein the respective drill holes provided in the surface of the at least one diffuser tube have a predefined bore diameter, and wherein the plurality of drill holes provided in the surface of the at least one diffuser tube are further arranged according to a fixed bore spacing grid.

4. The gas extinguishing system according to claim 1, wherein the drill holes provided in the surface of the at least one diffuser tube are configured to respectively release the inert gas into the protected area during the flooding period as a subcritical flow.

5. The gas extinguishing system according to claim 1, wherein the drill holes provided in the surface of the at least one diffuser tube have a constant cross section.

6. The gas extinguishing system according to claim 1, wherein, relative to a bore surface, an amount of inert gas released into the protected area through each individual drill hole of the at least one diffuser tube per second during the flooding period does not exceed a predefined value of 4.86?105 liter/(s?m2 bore surface) measured at 20? C. and 1.013 bar.

7. The gas extinguishing system according to claim 1, wherein, relative to an internal cross-sectional area of the at least one diffuser tube, a total amount of inert gas released into the protected area through the drill holes of the at least one diffuser tube per second during the flooding period does not exceed a predefined value of 2.92?105 liter/(s?m2 internal cross-sectional area), measured at 20? C. and 1.013 bar.

8. The gas extinguishing system according to claim 1, wherein nitrogen or a nitrogen-enriched gas mixture is used as the inert gas, and wherein an amount of inert gas released per second into the protected area through each individual drill hole of the at least one diffuser tube during the configured flooding period does not exceed a predefined value of approximately 0.004 kg/s; and/or wherein nitrogen or a nitrogen-enriched gas mixture is used as the inert gas, and wherein the diffuser system operating with a total amount of inert gas released per second into the protected area through the drill holes of the at least one diffuser tube during the flooding configured period does not exceed a predefined value of approximately 0.75 kg/s.

9. The gas extinguishing system according to claim 1, wherein the inert gas source comprises at least one inert gas pressure tank in which the inert gas is stored in compressed form.

10. The gas extinguishing system according to claim 1, wherein the at least one diffuser tube is positioned vertically in the protected area, and where the diffuser system further including at least one fluidly connected head pipe arranged between the pressure reducer and the diffuser tube through which inert gas is piped from the pressure reducer to the diffuser tube.

11. The gas extinguishing system according to claim 1, wherein the diffuser system further includes at least one support tube which terminates the at least one diffuser tube.

12. The gas extinguishing system according to claim 1, wherein the at least one diffuser tube is configured as a straight tube without bends, angles or T-pieces.

13. The gas extinguishing system according to claim 1, wherein the at least one diffuser tube is formed from a plurality of separately formed segments, wherein the plurality of separately formed segments are fluidly connected to one another by means of a cold-press connection.

14. The gas extinguishing system according to claim 1, wherein the gas extinguishing system further comprises the following: a fire detection device operating to detect at least one fire characteristic in the protected area; and a control device operating to automatically control the inert gas source as a function of the at least one fire characteristic monitoring and lower oxygen concentration in the protected area to a predefined inerting level according to a predefined sequence of events within the flooding period set for the protected area and maintain it at the inerting level for a predefined dwell time.

15. The gas extinguishing system according to claim 14, further comprising at least one system operating to detect the oxygen concentration in the protected area is further provided.

16. The gas extinguishing system according to claim 2, wherein the respective drill holes provided in the surface of the at least one diffuser tube exhibit a predefined bore diameter, and wherein the plurality of drill holes provided in the surface of the at least one diffuser tube are further arranged according to a fixed bore spacing grid.

17. The gas extinguishing system according to claim 2, wherein the drill holes provided in the surface of the at least one diffuser tube are configured to respectively release the inert gas into the protected area during the flooding period as a subcritical flow.

18. The gas extinguishing system according to claim 3, wherein the drill holes provided in the surface of the at least one diffuser tube are configured to respectively release the inert gas into the protected area during the dimensioned flooding period as a subcritical flow.

19. The gas extinguishing system according to claim 2, wherein the drill holes provided in the surface of the at least one diffuser tube have a constant cross section.

20. The gas extinguishing system according to claim 3, wherein the drill holes provided in the surface of the at least one diffuser tube have a constant cross section.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention description below refers to the accompanying drawings, of which:

(2) FIG. 1 the basic schematic structure of one exemplary embodiment of the inventive gas extinguishing system;

(3) FIG. 2 a schematic depiction of the diffuser system employed in the gas extinguishing system according to FIG. 1 with detailed sectional views of the diffuser system pressure reducer as well as the connection areas between two adjacent and connected diffuser tube segments;

(4) FIG. 3 the basic schematic structure of a further exemplary embodiment of the inventive gas extinguishing system; and

(5) FIG. 4a, b schematically differing diffuser system embodiments applicable to a gas extinguishing system according to the present invention.

DETAILED DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT

(6) FIG. 1 depicts the basic schematic structure of an exemplary embodiment of the inventive gas extinguishing system 1. Among the essential components of the gas extinguishing system 1 are in particular an inert gas source 2 as well as a diffuser system 4 fluidly connected or connectable to the inert gas source 2 by means of a tubing system 3.

(7) In the embodiment of the inventive gas extinguishing system 1 depicted schematically in FIG. 1, the inert gas source 2 is formed from a plurality of pressure cylinders 2.1 in which inert gas (here: preferably nitrogen) is stored in compressed form. It is for example conceivable to use commercially available 300 bar cylinders having a 140-liter capacity as pressure cylinders 2.1.

(8) The following will assume that nitrogen or a nitrogen-enriched gas mixture is used as the inert gas for the exemplary embodiments of the inventive gas extinguishing system 1 depicted in the drawings, whereby this is however not to be construed as being limiting. Other inert gases or inert gas mixtures or quenching gases can of course also be used to extinguish a fire.

(9) In the exemplary embodiment of the inventive gas extinguishing system 1 according to FIG. 1, the individual pressure cylinders 2.1 are each fluidly connected or connectable to the end region of the tubing system 3 facing the inert gas source 2 by means of a valve comprising a flow regulator 5. In order for the inert gas (here: preferably nitrogen) stored in the pressure cylinders 2.1 to be fed into the tubing system 3, the respective valves 5 of the pressure cylinders 2.1 are controlled by a control box (here: 200 bar pressure tank having an 80-liter capacity) in the exemplary embodiment depicted schematically in FIG. 1.

(10) The inert gas source 2 as well as the tubing system 3 of the embodiment of the inventive gas extinguishing system depicted schematically in FIG. 1 are configured in customary manner, as is the case with gas extinguishing systems having extinguishing nozzles. Instead of extinguishing nozzles, however, the inventive gas extinguishing system 1 makes use of a (nozzle-free) diffuser system 4.

(11) As can be seen particularly from the depiction provided in FIG. 2, the diffuser system 4 consists substantially of a diffuser tube 7 and a pressure reducer 8 allocated to the diffuser tube 7. The structure of the pressure reducer 8 can be recognized in the upper detailed sectional view of FIG. 2.

(12) According thereto, the pressure reducer 8 according to this embodiment comprises a baffle 9 as well an adapter piece 10. The adapter piece 10 fluidly connects the pressure reducer 8 to the end region of the tubing system 3 on the far side from the inert gas source 2. The adapter piece 10 further serves to fluidly connect the pressure reducer 8 to the (in FIG. 2: upper) end region of the diffuser tube 7 such that the pressure reducer 8 with the associated baffle 2 is fluidly arranged between the tubing system 3 and the diffuser tube 7.

(13) The diffuser tube 7 depicted schematically in FIG. 2 is of multi-piece construction and consists of individual segments 7.1, 7.2 and 7.3, whereby two respective adjacent segments 7.1, 7.2 or 7.2, 7.3 of the diffuser tube 7 are in each case fluidly connected together by means of a corresponding connecting piece 11. The connecting piece 11 can be provided with, as indicated in the lower FIG. 2 detail view, a corresponding seal 12; it is however advantageous within the context of the present invention for the connecting piece 11 to cold-press connect with the corresponding end region of the diffuser tube segments to be connected without the use of a seal 12 (cf. the middle FIG. 2 detail hereto).

(14) The diffuser system 4 employed in the exemplary embodiment according to FIG. 1 is designed as a non-reactive add-on component such that it makes no difference from the standpoint of the design of the gas extinguishing system 1 whether the diffuser system 4 or a standard extinguishing nozzle, for example in the form of a single-jet nozzle, is connected to the end region of the tubing system 3 on the far side from the inert gas source 2.

(15) For this reason, the diffuser system 4 in the exemplary embodiment of the inventive gas extinguishing system 1 according to FIG. 1 is designed in such a manner that, on the one hand, a primary baffle pressure measured in absolute bar is at least twice as high as the internal pressure of the diffuser tube 7 during a flooding period dimensioned with respect to the protected area 14 and, on the other, that the internal pressure of the diffuser tube 7 is at a maximum of 2 bar absolute during the configured flooding period.

(16) These design criteria which relate to the primary baffle pressure on one hand and to the internal diffuser tube 7 pressure on the other guarantee the desired non-interactiveness of the diffuser system 4.

(17) Additionally hereto, the exemplary embodiment of the inventive gas extinguishing system 1 depicted schematically in FIG. 1 provides for the inert gas to be able to be released into the protected area 14 associated with the gas extinguishing system 1 via the diffuser tube 7 pursuant to a uniform distributive function.

(18) To this end, it is provided with the gas extinguishing system 1 shown in FIG. 1 for the same mass flow of inert gas to be discharged from all the drill holes 13 formed in the surface of the diffuser tube 7 during the flooding period configured for the protected area 14 associated with the gas extinguishing system 1.

(19) The diffuser tube 7 employed in the inventive gas extinguishing system 1 has a plurality of drill holes 13 provided in its surface via which at least a portion of the inert gas provided by the inert gas source 2 can be introduced into the protected area 14 associated with the gas extinguishing system 1 as needed or in the event of a fire. The diffuser tube 7 thereby serves to redirect the inert gas flow from the longitudinal direction of the diffuser tube 7 into a radial direction relative to the diffuser tube 7 and non-reactively release the inert gas into the protected area.

(20) Preferably, and as schematically indicated in FIG. 2, the respective drill holes 13 provided in the surface of the diffuser tube 7 exhibit a predefined bore diameter, whereby it is of further advantage for production-related reasons for the drill holes 13 to be arranged according to a fixed bore spacing grid.

(21) For the diffuser system 4 to be able to realize the gentlest possible flooding of the protected area 14 associated with the gas extinguishing system 1, it is advantageous for preferably all of the respective drill holes 13 provided in the surface of the at least one diffuser tube 7 to be designed such that the inert gas supplied to the diffuser tube 7 during the configured flooding period is released into the protected area 14 as a subcritical flow. Such a subcritical flow can then at any rate be realized when the respective drill holes consistently exhibitas seen across the thickness of the diffuser tube 7 walla constant cross section and thus in particular do not exhibit a nozzle shape.

(22) The gas extinguishing system 1 depicted schematically in FIG. 3 corresponds substantially to the basic structure of the system described with reference to the FIG. 1 representations. To avoid repetition, the following will refrain from describing similar components of the gas extinguishing system 1 shown in FIG. 3 or components which produce the same effect. Instead, the following remarks concentrate on those aspects of the inventive gas extinguishing system 1 provided additionally in the embodiment depicted schematically in FIG. 3.

(23) As depicted schematically in FIG. 3, the gas extinguishing system 1 shown therein is associated with a specific protected area 14, whereby the present case for example relates in particular to a small-parts storage system such as a vertical high-density storage system (shuttle or paternoster system).

(24) A total of two diffuser systems 4 are arranged on the tubing system 3 of the gas extinguishing system 1 depicted schematically in FIG. 3, their respective diffuser tubes 7 aligned vertically. The inert gas is fed into the respective diffuser tubes 7 from below in the diffuser system 4 depicted on the left in FIG. 3 whereas the inert gas is fed into the diffuser tube 7 from above in the diffuser system 4 shown on the right.

(25) A control device 15 is further indicated in FIG. 3, which can be realized as part of a central fire alarm system (BMZ). The control device 15 serves to appropriately control the inert gas source 2 when needed so as to initiate an inerting of the protected area 14 associated with the gas extinguishing system 1 or to respectively ensure that a predefined inerting level is not exceeded in the protected area 14 for a predefined or predefinable period of time.

(26) To this end, the gas extinguishing system 1 depicted schematically in FIG. 3 is provided with a fire detection device 16 as well as a system for detecting the oxygen concentration in the protected area 14 (not shown). The fire detection device 16 is preferably configured as an aspirative system and designed to detect at least one fire characteristic in protected area 14.

(27) The control device 15 preferably automatically controls the inert gas source 2 as a function of the fire characteristic monitoring realized by means of the fire detection device 16 such that the oxygen concentration in the protected 14 is lowered to a predefined inerting level according to a predefined sequence of events within the flooding period configured for the given protected area 14. It is thereby advantageous for the preferably automatic initiating of the inert gas source 2 to occur together with a corresponding alarm being issued. To this end, an alarm mechanism 18 is provided in the schematic depiction of FIG. 3.

(28) The gas extinguishing system 1 is preferably further provided with the above-cited system 17 for detecting the oxygen concentration in the protected area 14 so as to ensure a sufficient amount of inert gas will be supplied to the protected area 14 in order to set and maintain the required inerting level in said protected area 14. Further flooding may be necessary to supply additional inert gas.

(29) FIGS. 4a and 4b show various embodiments of diffuser systems 4 which can be used with the gas extinguishing system 1 according to the invention as non-reactive add-on components.

(30) In detail, FIG. 4a shows three different embodiments of the diffuser system 4, whereby the inert gas is fed into the respective diffuser system 4 in each case from above. This type of inert gas feed from above is in particular feasible for protected areas 14 having a maximum height of 22 m.

(31) In order to achieve as even of a dispersal of the inert gas in the protected area 14 as possible, the diffuser tube 7 of the respective diffuser systems 4 isas indicated in FIG. 4adisposed at different vertical heights. The vertical positioning of the diffuser tube 7 in the protected area 14 thereby occurs by using at least one head pipe 19 and/or by using at least one support tube 20. The head pipe(s) 19 and support tube(s) 20 are each configured without drill holes in their surfaces and primarily serve only in the vertical positioning or mechanical supporting of the respective diffuser tube 7.

(32) FIG. 4b shows a configuration of diffuser systems 4 able to be used in protected areas 14 taller than 22 m. In this case, it is advantageous to partially modify the orientation; i.e. the feed of inert gas into the respective diffuser system 4, in order to distribute the respective diffuser tubes 7 over the entire height of the protected area 14.

(33) In principle, the end region of the diffuser tube 7 opposite the pressure reducer is to be capped. This is usually effected by an end cap 21 of a tubing section 20 or other such closure.

(34) The at least one diffuser system 4 used in the inventive gas extinguishing system 1 is designed to evenly disperse the extinguishing agent/inert gas, particularly nitrogen, within protected area 14 (extinguishing zone of small-parts storage systems) at minimum flow load. In so doing, the diffuser system 4 in the gas extinguishing system 1 assumes the structural function of the customarily employed standard extinguishing nozzle supplemented by the function of redirecting and dispersing the inert gas. The diffuser system 4 represents the terminal component of the gas extinguishing system 1 prior to the inert gas flowing into the protected area 14.

(35) The solution according to the invention is in particular characterized by the necessary configuring specifications and design methodology for the diffuser system 4to the extent of the configuration relating to the design and structure of the gas extinguishing system external of the protected area 14exhibiting no difference from a standard system with extinguishing nozzles.

(36) The pressure reducer 8 associated with the diffuser system 4 represents the system interface between the high-pressure section of the gas extinguishing system 1 and the diffuser tube 7. The pressure reducer 8 thereby separates the pressure-loaded area in the tubing system 3 (usually up to 60 bar) from the low-pressure area in the diffuser tube (maximum 1 bar positive pressure).

(37) According to one concrete embodiment of the inventive diffuser system 4, the diffuser tube 7 is formed by a straight DN 50 stainless steel tube open at both ends, with the pressure reducer 8 arranged at its start. Up to 220 drill holes having a diameter of 3.0 mm are formed on one section of the stainless steel tube, radially arranged in a line in a 50 mm grid. The inert gas flows into the diffuser tube 7 through the pressure reducer 8 and then radially exits the drill holes 13 uniformly.

(38) The flooding period dimensioned for the protected area 14 is stipulated in the respective national regulations, for example in the respective VdS Guidelines issued by German loss insurers.

(39) Thus, for small-parts storage systems not yet VdS-certified for protecting equipment, the diffuser systems 4 are to be configured pursuant to e.g. VdS 2380 area protection. Area protection according to the VdS 2380 specifies inert gas extinguishing system stipulations for minimizing the risk of fire in communal areas comprising highly diverse fire loads (combustible materials) and different ignition sources. The guideline relates to extinguishing by means of inert gases and inert gas mixtures.

(40) According to VdS 2380, the type of fire risk determines the flooding period (95% extinguishing gas concentration passage) for small-parts storage systems at a maximum of 60 or 120 seconds in addition to the specified concentration and the dwell time of 10 or 20 min respectively.

(41) The invention is not limited to the example embodiments schematically depicted in the drawings but rather yields from a synopsis of all the features disclosed herein together.

LIST OF REFERENCE NUMERALS

(42) 1 gas extinguishing system 2 inert gas source 2.1 pressure cylinder/pressure tank 3 tubing system 4 diffuser system 5 valve with pressure reducer 6 control box 7 diffuser tube 7.1, 7.2, 7.3 diffuser tube segments 8 pressure reducer 9 baffle 10 adapter piece 11 connecting piece 12 seal 13 drill hole 14 protected area 15 control device 16 fire detection device 18 alarm mechanism 19 head pipe 20 support tube 21 closure