Abstract
A fire protection device for small electrical devices provided with a housing. The fire protection device includes a bursting capsule featuring a hollow space that is completely enclosed and delimited by a vessel wall, wherein a liquid is disposed in the hollow space. The liquid breaks the vessel wall at a predetermined trigger temperature due to thermal expansion thereby causing the bursting capsule to rupture. When the vessel wall ruptures and releases the liquid it has a fire preventing effect and/or a fire extinguishing effect.
Claims
1. A small electrical appliance comprising: a housing in which electrical components are disposed; and a fire protection device disposed in the housing, wherein the fire protection device comprises a bursting capsule featuring a hollow space that is completely enclosed and delimited by a vessel wall, and wherein a liquid is disposed in the hollow space, which a) breaks the vessel wall at a predetermined trigger temperature due to thermal expansion thereby causing the bursting capsule to rupture; and b) has a fire preventing effect and/or an extinguishing effect.
2. The small electrical appliance according to claim 1, wherein the fire protection device further comprises: an electrical conductor routed between two contact points formed on the bursting capsule; wherein the electrical conductor is formed in such a way that the electrical conductor is destroyed when the bursting capsule ruptures; and an electrical supply line for the small electrical device is connected with the contact points on the bursting capsule and is routed through the electrical conductor between these contact points.
3. The small electrical appliance according to claim 2, wherein the electrical conductor is formed in such a way that the electrical conductor is automatically and inadvertently destroyed when the bursting capsule ruptures, thereby cutting power to the electrical components located within the housing.
4. The small electrical appliance according to claim 1, wherein the liquid reaches boiling point at a temperature below the trigger temperature.
5. The small electrical appliance according to claim 1, wherein the liquid is a fluorinated ketone.
6. The small electrical appliance according to claim 5, wherein the fluorinated ketone is a perfluorinated ethyl isopropyl ketone.
7. The small electrical appliance according to claim 1, wherein the liquid is a halon.
8. The small electrical appliance according to claim 1, wherein in addition to the liquid, a gas bubble is also disposed in the hollow space of the bursting capsule.
9. The small electrical appliance according to claim 8, wherein the gas bubble disposed in the hollow space is comprised of a gas that does not promote fire.
10. The small electrical appliance according to claim 9, wherein the gas in the gas bubble is comprised of nitrogen or carbon dioxide.
11. The small electrical appliance according to claim 1, wherein the liquid turns to foam when the bursting capsule ruptures.
12. A use of a bursting capsule featuring a hollow space that is completely enclosed and delimited by a vessel wall, wherein a liquid is disposed in the hollow space, which c) breaks the vessel wall at a predetermined trigger temperature due to thermal expansion, thereby causing the bursting capsule to rupture, and d) has a fire preventing effect and/or an extinguishing effect; as a fire protection device for a small electrical device by disposing that bursting capsule in a housing of the small electrical device.
Description
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0020] Further advantages and characteristics of the invention will become apparent in the following description of possible embodiments with reference to the accompanying figures. These include:
[0021] FIG. 1 a schematic view of a possible fire protection device according to the invention;
[0022] FIG. 2 a view similar to that in FIG. 1 showing an alternative embodiment of a fire protection device according to the invention;
[0023] FIG. 3 a view similar to that in FIG. 1 showing another alternative embodiment of a fire protection device according to the invention;
[0024] FIG. 4 a schematic representation of a small electrical device equipped with a fire protection device according to the invention; here, a power adaptor; and
[0025] FIG. 5 an alternative embodiment of a small electrical device equipped with a fire protection device according to the invention; here again, a power adaptor.
[0026] The figures show possible schematic representations of embodiments of the invention. The figures are not at all drawn to scale and do not show all details; rather, these are schematic diagrams intended to illustrate the essential features of the invention in conjunction with the following description of the embodiments.
DETAILED DESCRIPTION OF THE INVENTION
[0027] FIG. 1 is a schematic diagram of a bursting capsule 1, which is an essential component of a fire protection device according to the invention. The interior of this bursting capsule 1, which here is a so-called glass vessel formed from a glass tube, features a hollow space 2 that is completely enclosed by the vessel wall. The bursting capsule 1 is essentially cylindrical in shape with two thickened ends 3, 4. The bursting capsule 1 is disposed and is held between two supports 5, 6 at the ends 3, 4. A liquid is disposed in the hollow space 2 (not shown here), which, together with a small gas bubble, nearly fills the volume of the hollow space 2. On the one hand, this liquid is selected such that it causes the bursting capsule 1 to rupture at a predetermined trigger temperature due to thermal expansion, for example 50 C., 60 C., 65 C., 70 C. or 90 C., and on the other hand, such that it exhibits a fire inhibiting effect and/or an extinguishing effect. In this way, when the trigger temperature is reached or exceeded, the liquid in the bursting capsule is released when the vessel ruptures, and can achieve the desired fire inhibiting effect or extinguishing effect inside the housing of a small electrical device.
[0028] The liquid here is selected in an advantageous manner so that its boiling point is at a temperature that falls below the trigger temperature, or in other words that abruptly enters the gas phase when it is released upon reaching or exceeding the trigger temperature and therefore takes up a greater volume than the volume of the hollow space 2. Thus a comparatively small quantity of liquid can fill a comparatively large volume within the housing of a small electrical device with the corresponding gas, which arises from the liquid and therefore can achieve the fire inhibiting effect or extinguishing effect there.
[0029] A halon may be considered as a possible liquid in the hollow space 2. A fluorinated ketone is also suitable however, wherein in this embodiment, a perfluorinated ethyl isopropyl ketone according to the following structural formula
##STR00001##
is preferable.
[0030] FIG. 2 shows an alternative embodiment of such a bursting capsule 1 as a fire protection device. The primary components are essentially the same as those in the bursting capsule 1 in FIG. 1, and it simply includes an additional electrical conductor 7, which runs along the longitudinal axis of the bursting capsule 1, through the hollow space 2 and passes out through the respective ends 3 and 4. When this bursting capsule is used, this electrical conductor can be used as a fire protection device, for example, in order to conduct a supply voltage for the small electrical device. In so doing, the thickness of the electrical conductor 7 is selected in such a way that the electrical conductor 7 breaks, and is destroyed when the bursting capsule 1 ruptures as a result of the trigger temperature being exceeded. The result is that, in the event of triggering, not only is the fire inhibiting effect or extinguishing effect of the liquid contained in the hollow space 2 triggered or achieved, but at the same time the power supply to the electrical device is also cut off. Otherwise, the structure of the bursting capsule shown in FIG. 2 is the same as that in FIG. 1 and the functioning is identical as well.
[0031] FIG. 3 shows a further alternative of a bursting capsule 1, which in turn is essentially designed and functions as described in FIG. 1. In deviating from the embodiment shown in FIG. 1, in the case of the bursting capsule 1 according to FIG. 3, an electrically conductive coating 8 has been applied to a section of the exterior of the bursting capsule, which extends from one end 3 of the bursting capsule 1 to the other end 4. Contact can be established with this electrically conductive coating 8 via the supports 5 and 6, which come into contact with the coating 8 as shown, thereby forming an electrical conductor that runs along the longitudinal axis of the bursting capsule 1 and can be routed through an electrical supply of the small electrical device, for example. Here again, the rupture of the bursting capsule 1 as a result of pressure due to the thermal expansion of the liquid in the hollow space 2 when it exceeds the trigger temperature, which pressure the wall of the bursting capsule 1 cannot withstand at or above the trigger temperature, results in a break in the conductor formed by the electrically conductive coating 8 and therefore to an interruption in the current or voltage supply of the small electrical device equipped with this fire protection device. Otherwise, the structure and functioning of the bursting capsule shown in FIG. 3 is the same as that in FIG. 1, so that again, reference can be made to the description of this figure.
[0032] FIG. 4 shows a schematic representation of a power adaptor 10 as an example of a small electrical device according to the invention. The power adaptor 10 features a housing 11, in which the various components are disposed. A power cable 12 runs into the housing for connecting to the mains power supply. A unit cable 13 runs from the housing, which acts as a voltage-adapted power supply for the device. A voltage converter 14 and additional electrical components 15, 16 on a printed circuit board 17 are disposed within the housing 11. The voltage converter 14 is connected with the power cable 12 on the input side with both wires, and on the output side, the voltage converter 14 supplies the unit cable 13. A bursting capsule 1 according to FIG. 1 is disposed as a fire protection device within the housing 11 between supports 5 and 6. If overheating that exceeds trigger temperature of the bursting capsule 1 now occurs in the power adaptor 10 as a result of a malfunction, the liquid disposed in the hollow space of the bursting capsule 1 causes the bursting capsule to rupture and thus develops its fire inhibiting effect or extinguishing effect.
[0033] FIG. 5 shows an alternative embodiment of a small electrical device according to the invention in the form of a power adaptor 10. Here again, the power adaptor 10 is enclosed by a housing 11, into which a power cable 12 extends that is connected to the mains voltage on the input side, from which the unit cable 13 extends with the device voltage adapted to the conditions for the electrical device being supplied. Again the voltage converter 14 and additional electrical components 15, 16 are disposed on a printed circuit board 17. In contrast to the preceding embodiment, both wires of the power cable 12 are no longer directly connected to the voltage converter 14, but rather, one wire 18 is routed to the bursting capsule 1, which here is designed in accordance with the embodiment in FIG. 2, and connected to the electrical conductor 7 formed there in this embodiment. Connected on the opposite side to the electrical conductor 7 is an additional wire 19 from a connection cable, which then runs to the input of voltage converter 14. This design, which varies from the embodiment in FIG. 4, ensures that in the event that the bursting capsule 1 is triggered, the electric conductor 7 will break, thereby interrupting the supply voltage to the power adaptor 10 from the power cable 12. Here, in addition to the fire inhibiting effect or extinguishing effect from the liquid disposed in the bursting capsule 1, it is also guaranteed that the power is also interrupted in the manner of a fuse. Naturally an embodiment of the bursting capsule 1 according to FIG. 2 could be replaced with the design in FIG. 3 in the embodiment according to FIG. 5 with the same effect.
[0034] In particular, it is to be understood here that the volume ratios between the volume of the hollow space of the bursting capsule to the total volume of the housing shown in FIGS. 4 and 5 are not to scale. Here, the bursting capsule 1 has been enlarged for better illustration. In so doing, the volume capacity of the bursting capsule 1 has been designed in such a way that upon triggering and the vaporizing of the liquid form of the chemical substance contained therein, said liquid, which is then in a gaseous state, will reliably fill the internal volume of the housing 11.
LIST OF REFERENCE DRAWINGS
[0035] 1 bursting capsule [0036] 2 hollow space [0037] 3 end [0038] 4 end [0039] 5 support [0040] 6 support [0041] 7 electrical conductor [0042] 8 electrically conductive coating [0043] 10 power adaptor [0044] 11 housing [0045] 12 power cable [0046] 13 unit cable [0047] 14 voltage converter [0048] 15 electrical component [0049] 16 electrical component [0050] 17 printed circuit board [0051] 18 wire [0052] 19 wire
