HK1124004B - Method and device for fire prevention and/or fire fighting in closed rooms - Google Patents

Description

The present invention relates to a process and device for fire prevention and/or fire suppression in enclosed spaces, the ambient air atmosphere of which must not exceed a prescribed temperature.

An enclosed space whose ambient air atmosphere must not exceed a prescribed temperature, such as a cold store, an archive or a computer room, shall normally be equipped with air conditioning to provide adequate air conditioning. The air conditioning system shall be designed and dimensioned in such a way that sufficient heat or thermal energy can be removed from the ambient air of the enclosed space to maintain the temperature inside the room within a prescribed range. For example, in a cold store, the temperature to be maintained is normally at a value that requires near-continuous cooling and therefore the continuous operation of an air conditioning system, as this also allows for the avoidance of permanent temperature fluctuations. This is particularly true for refrigeration units operating at temperatures up to -20°C.

However, air conditioning must also be used in, for example, computer rooms or control cabinets to avoid that the temperature of the room air atmosphere reaches a critical value, in particular due to the waste heat generated inside the room by electronic components etc.

The size of the air conditioning system shall be chosen so that at any time a sufficient amount of heat can be removed from the room air atmosphere so that the temperature inside the room does not exceed the temperature value specified according to the needs and the application case.

The amount of heat to be removed from the air-atmosphere by the air conditioning system depends on the heat stream that is diffused through the enclosure into the interior of the room (heat conduction). Furthermore, if there are also objects radiating heat in the enclosed space, the waste heat generated inside the room contributes to the amount of heat to be removed to the outside. In particular, in the case of server rooms and switchboards housing computer components, adequate waste heat removal is crucial to prevent overheating and malfunctioning or even destruction of the electronic components.

On the other hand, it is known as preventive fire protection to address a fire hazard in enclosed spaces, for example where people only occasionally enter and where equipment is sensitive to water exposure, by permanently reducing the oxygen concentration in the room air atmosphere to a certain inertisation level, for example 15 vol. % oxygen content or lower.

Such an inerting system for enclosed spaces is described, for example, in DE 198 11 851 A1.

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However, the use of inertisation technology in rooms where the ambient air must not exceed a specified temperature level presents certain problems, since the ambient air of the enclosed space must be monitored regularly or continuously to maintain an inert gas level set in the ambient air. Otherwise, the consciously adjusted oxygen concentration differences between the ambient air of the enclosed space on the one hand and the outer atmosphere on the other hand would disappear sooner or later depending on the airtightness and air exchange rate.

Accordingly, conventional systems where inertisation technology is used as a preventive fire protection technique are usually equipped with a system for supplying an oxygen-displacing gas (inert gas) which is designed to supply the room with an inert gas sufficient to maintain the level of inertisation, depending on the oxygen content in the room's atmosphere. In particular, a nitrogen generator connected to a compressed air compressor is used to supply an inert gas, which, if necessary, generates the inert gas (i.e. nitrogen with sufficient air) directly in the room. In the case of a generator of this type, the normal nitrogen gas is discharged into a compressed air and separated from the remaining nitrogen gas in the room, thus reducing the nitrogen content and the amount of nitrogen remaining in the room.

The nitrogen enriched air supply is normally activated when the oxygen concentration in the room air atmosphere exceeds a specified threshold value, which is selected depending on the level of inertisation to be maintained.

The use of such a fire prevention system in rooms where the ambient air must not exceed a specified temperature value has certain disadvantages, since it is not possible to avoid the addition of thermal energy (heat) to the ambient air of the enclosed space due to the regular or continuous removal of inert gas. This additional heat must then be discharged back to the air conditioning system. The air conditioning unit must be increased accordingly to the future use of the air conditioning system. In particular, it must be ensured that the additional heat that is discharged to the interior of the room due to the continuous or regular removal of inert gas can also be effectively discharged.

In addition, it should be noted that the nitrogen enriched air produced in a nitrogen generator and introduced into the interior of the room is generally at a temperature higher than the temperature of the outside air.

Even if a nitrogen generator is not used to supply inert gas, but steel cylinders, etc., in which the inert gas is stored compressed, it must be taken into account that even here an additional amount of heat is often introduced into the ambient air of the enclosed space.

It is therefore clear that the use of a conventional inertisation technique in enclosed spaces where the ambient air must not exceed a specified temperature is associated with increased operating costs, since the air conditioning system required to air condition the room must be of a correspondingly larger size.

The present invention is based on this problem, therefore, on the task of specifying a method and device for fire prevention for enclosed spaces where the ambient air is kept within a specified temperature range by means of an air conditioning system, etc., without the need to increase the cooling capacity provided by the air conditioning system even if inert gas is continuously or regularly introduced into the ambient air in order to set or maintain a certain level of inertisation inside the enclosed space.

This is achieved by a process of the type described at the outset, which consists of first supplying a liquefied inert gas (such as nitrogen) in a container, then supplying a portion of the inert gas supplied to an evaporator and evaporating it, and finally supplying the evaporated inert gas to the ambient atmosphere of the enclosed space in a regular manner so that the oxygen content in the ambient atmosphere of the enclosed space is reduced to a certain inertisation level and/or maintained at a certain (previously set) inertisation level. In particular, the invention provides that the heat energy required to evaporate the liquid gas is either directly or indirectly released into the atmosphere of the room.

With regard to the device, the purpose of the invention is to provide that the device of the type described at the outset has, on the one hand, an oxygen measuring device for measuring the oxygen content in the ambient air of the enclosed space and, on the other hand, a device for the controlled introduction of inert gas into the ambient air of the enclosed space. In particular, the device is intended to have a container for the provision and storage of the inert gas in liquefied form and a vapour connected to the container. The purpose of the vapouriser is to evaporate at least part of the liquid inlet gas contained in the container and, on the other hand, to inject a vapour inlet gas into the ambient air of the enclosed space in order to remove a specific type of greenhouse gas. In particular, the vapouriser is designed to be used in a direction directed to the heating of the liquid inlet gas contained in the enclosed space, depending on the level of the liquid or vapouriser inlet gas contained in the container. The vapouriser is designed to be used in a direction directed to the heating of the liquid or vapouriser gas contained in the ambient air (in particular, the direction of the vapouriser) and is designed to control the vapourization of the vapourization gas inlet gas inlet gas inlet gas inlet gas inlet gas in the enclosed space (in the enclosed space) in a specific direction, depending on the level of the vapourization of the vapourization gas inlet gas inlet gas contained inlet gas.

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The advantages of the solution of the present invention are obvious. By taking the heat energy required in the evaporator to evaporate the liquid inert gas from the ambient air of the enclosed space, a cooling effect can be achieved inside the room, simultaneously with the tracing or introduction of inert gas into the ambient air. This cooling effect can be used to keep the ambient air temperature within the specified temperature. The use of this synergistic effect can - despite the use of inertisation technology - even maintain or reduce the cooling power provided by an air conditioning system.

The device of the invention is a systematic implementation of the method of the invention for providing preventive fire protection in rooms where the ambient air atmosphere must not exceed a specified temperature.

Beneficial training on the process of the invention is given in subclauses 2 to 12 and on the device of the invention in subclauses 14 to 22.

In a particularly favourable embodiment of the solution of the present invention, the evaporation of the inert gas provided is carried out within the enclosed space, providing that, before the inert gas is evaporated, it is supplied in liquid form to an evaporator located inside the room, which is a particularly easy to implement but nevertheless effective way of extracting a certain amount of heat (evaporation heat) from the room air atmosphere by evaporating the liquid inert gas inside the room and cooling the room without the use of an air conditioning system.

Alternatively, however, it is conceivable that the inert gas supplied is evaporated not inside but outside the enclosed space, whereby the heat energy required to evaporate the inert gas should be obtained at least in part via the thermal conduction of the indoor air atmosphere of the enclosed space, for example by using an evaporator located outside the enclosed space.

In the latter embodiment, where the inert gas is evaporated outside the enclosed space, it is advantageous to regulate the amount of heat energy extracted from the room air atmosphere by conduction to evaporate the inert gas, for example by adjusting the thermal conductivity of a heat conductor used to extract the required heat. Preferably, the thermal conductivity of the heat conductor is set according to the temperature of the is, i.e. the temperature present and measured in the enclosed space, and/or a pre-set T-temperature.

In order to achieve this further development, it is preferable that the device also has a temperature measuring device for measuring the temperature of the ambient air of the enclosed space, in order to be able to determine the actual temperature of the enclosed space continuously or at specified times and/or events. The thermal conductivity of the heat conductor used to extract the amount of heat required for evaporation can then be set depending on the measured ambient temperature. In particular, it is conceivable that a heat exchanger should be used to transfer the heat from the ambient air to the heat exchanger to be evaporated in the evaporator. The control of the heat transfer rate of the heat transfer device should be based on a measurable temperature and a measurable heat transfer rate.

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The technical principle underlying an air evaporator is particularly simple and error-proof to implement. It is conceivable, for example, that the air evaporator consists of aluminium tubes with longitudinal stripes. Such an air evaporator works in particular without additional external energy, i.e. only by heat exchange with a volume of air taken from the ambient air of the enclosed room. In this way, the liquefied inert gas can be evaporated and heated to almost the ambient air temperature. At the same time, the heat energy required from the inert gas is preferably extracted via heating air conditioning, which is used as a heat exchanger for the insulation or evaporator, so that this heat can be dissipated in a small proportion in the air of the room, which can be used directly for the heating of the air in the room, in particular in the case of a greenhouse gas.

This cooling effect is in particular decoupled from the cooling power of an air conditioner used to air condition the enclosed space. In particular, this embodiment uses an air evaporator with a heat exchanger, using the inert gas to be introduced into the enclosed space as the heating medium and a fraction of the air from the room air atmosphere as the cooling medium.

Preferably in this embodiment, the heat exchanger of the air evaporator is connected to the enclosed space via an air duct system, so that, on the one hand, warm air from the room air atmosphere can be supplied to the heat exchanger (as the cooling medium); on the other hand, the air duct system is used to allow, after the evaporation of the liquefied inert gas, the air supplied to the air evaporator heat exchanger to be reintroduced into the enclosed space as cooled air (cold air); in particular, it is preferred that at least one hot air duct be used to remove the air from the room air atmosphere, which also serves to remove the warm air used to cool the air into the room atmosphere, if necessary, in a closed air conditioning system.

On the other hand, it is also preferable that the (warm) air supplied to the heat exchanger of the air evaporator, after evaporation of the inert gas, is returned to the enclosed space via a cold air channel as cooled (cold) air, which can also be used to return the air cooled from the air conditioning system used to air condition the enclosed space to the room air atmosphere if necessary.

The joint use of the hot air channel and the cold air channel by the air conditioning unit on the one hand and the heat exchanger of the air evaporator on the other, makes it possible to use the solution of the invention in an enclosed space without major construction work, in particular because no additional air channels need to be provided.

Finally, as regards the device, another advantage is that the heat exchanger can also be designed as a component of an air conditioning system used for air conditioning the enclosed space. For example, it is conceivable that the air conditioning system itself has a heat exchanger through which a partial amount of air from the room air atmosphere is passed to transfer thermal energy from the air to a cooling medium.

In the latter embodiment, where an air evaporator with a heat exchanger is used, it is preferable to provide that the amount of air supplied to the heat exchanger as warm air can be adjusted according to the actual temperature and/or a predefined target temperature.

With regard to the inert gas used in the solution of the invention, it is preferable to store it in the saturated state in the container, in particular at a temperature several degrees below the critical point for the inert gas.

For example, when nitrogen is used as an inert gas with a critical temperature of -147 °C and a critical pressure of 34 bar, it is preferable to store the nitrogen at a pressure in the range of 25 to 33 bar, preferably 30 bar, and the corresponding saturation temperature. It should be taken into account that the container pressure should be sufficiently high to allow the storage pressure to push the inert gas to the evaporator as quickly as possible. Preferably, a storage pressure of 20 to 30 bar is assumed so that the pipes connecting the pipes to store the liquefied inert gas to the evaporator can show a small continuous flow rate. For example, at a pressure of 30 bar, the storage temperature would be at -147 °C -150 °C, which is a large gap from the critical temperature.

The solution of the present invention is not only suitable for preventative fire protection, in which the flammability of the goods stored in the enclosed space is reduced by preferably permanent reduction of the oxygen content in the ambient air of the enclosed space; it is also conceivable that in the event of a fire or if necessary, the oxygen content of the ambient air can be further reduced to a certain level of full inertness by regularly introducing inert gases into the ambient air.

The setting (and holding) of the full inert level may be for example for the purpose of fire suppression, in which case it is preferable that the device also has a fire detection device to measure a fire characteristic in the atmosphere of the enclosed space.

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Thus, when the solution of the invention is used to extinguish fires, it is conceivable that the reduction to the level of full inertness depends on a detector measurement for a fire characteristic.

On the other hand, it is also conceivable that the reduction to the level of total inertisation depends on the goods stored in the enclosed space and in particular their ignition behaviour, so that it is possible to set a level of total inertisation also as a preventive fire protection measure in a room where, for example, particularly flammable goods are stored.

To reduce the oxygen content in the ambient air of the enclosed space to the level of full inertisation, it is conceivable to adjust the level of full inertisation by machine production and subsequent introduction of an oxygen displacement gas, but it is also possible to provide the inert gas to be added or to be added to set and maintain the level of full inertisation in the container, preferably as a refrigerating tank, and to evaporate it with the evaporator.

It is apparent that the solution of the invention can be used as a preventive fire protection in a closed refrigerated warehouse, a computer room or similar room, where the ambient air of that room must not exceed a temperature value.

The following are preferred embodiments of the device of the invention, described in the drawings.

It shows: Figure 1a schematic view of a first preferred embodiment of the device of the invention;Figure 2a schematic view of a second preferred embodiment of the device of the invention; andFigure 3a schematic view of a third preferred embodiment of the device of the invention.

Figure 1 shows a first preferred implementation of the solution of the present invention, which is a preventive fire protection measure in an air-conditioned room 10. Room 10 is, for example, a refrigerated warehouse or a computer room, i.e. a room whose ambient air atmosphere must not exceed a specified temperature value.

The air conditioning system used for the air conditioning of room 10 may be an air conditioning system not explicitly shown in the drawings, the operation of which is not to be described in detail here.

The invention describes a preventive fire protection measure for air-conditioned spaces, such as refrigeration units or computer rooms. The solution of the invention is characterised by the fact that, if necessary, the cooling effect of evaporation of an inert gas to be released into the room atmosphere is used either directly or indirectly to cool room 10. The solution of the invention can therefore be used to achieve a corresponding reduction in the cooling power provided by the air conditioning system. This not only reduces the operating costs of the entire system, but can also be adapted to the size of the air conditioning system when the small room is planned.

The first preferred embodiment of Figure 1 provides for the storage of an inert gas, such as nitrogen, in liquid form in a container 1 described here as a refrigeration tank, and for the purpose of preventing fire in the surrounding room 10 atmosphere, a certain level of inertisation can be set and maintained by supplying a part of the inert gas 37 in liquid form to a vapour 16 shown only in Figure 1 via a liquid gas line 8.

In the case of the system shown in Figure 1, the evaporator 16 is located inside the enclosed space 10. For example, the evaporator 16 may be an air evaporator at least partially surrounded by the air of the enclosed space. This makes it possible to keep the evaporator 16 almost always at room air temperature on the one hand and to convert the inlet gas supplied in liquid form into its gaseous state and thus evaporate it. The evaporator 16 can cool itself briefly during the evaporation of the inlet gas, but is subsequently heated by the room.

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In the first embodiment shown in Fig. 1, the evaporator draws the heat required to evaporate the inert gas 37 directly from the room air atmosphere of the enclosed room 10, since the evaporator 16 is located inside room 10. Thus, when the liquid inert gas 37 is evaporated, thermal energy is removed from the room air atmosphere of room 10 and the room air atmosphere of room 10 is cooled accordingly. This cooling effect, which is used to cool the room air atmosphere of room 10, occurs particularly when the inert gas is introduced into the room air atmosphere of room 10.

As shown, an inert gas line 3 is downlinked to the evaporator 16 to supply the inert gas evaporated in the evaporator 16 in the gaseous state to the exhaust nozzles 2.

In particular, the liquid inert gas 37 is supplied from tank 1 to evaporator 16 in a controlled manner 11 and a valve 9 is attached to the liquid gas line 8 which can be controlled by control 11.

The amount of inert gas to be evaporated in evaporator 16 and then introduced into chamber 10 is preferably controlled by a controlled valve 9 controlled by controller 11 to this end, which gives a control signal to the valve 9 assigned to the liquid gas line 8 by a control line 40. The valve 9 can be opened and closed in this way so that, if necessary, a certain amount of inert gas 37 stored in container 1 can be introduced into the room air atmosphere of chamber 10 after being introduced into evaporator 16 and evaporated there.

In particular, control 11 should be designed to independently give a corresponding control signal to valve 9 when inert gas must be introduced into the ambient air of enclosed room 10 in order to adjust or maintain the oxygen content of the ambient air to a certain inertisation level. By keeping the oxygen content of the ambient air at a certain inertisation level via the regulated inert gas supply, room 10 is permanently inerted to provide preventive fire protection.

The level of inertisation to be established or maintained in room 10 by regular supply or retention of inert gas is preferably chosen according to the fire load of the enclosed room 10. For example, it is conceivable that a relatively low oxygen content of, for example, about 12 vol.%, 11 vol.% or less may be established in the room air atmosphere when flammable substances or goods are stored in room 10.

On the other hand, it is also conceivable that control 11 controls valve 9 in such a way that, on the basis of an oxygen content of about 21% vol., a certain level of inertisation is first built up and then maintained inside chamber 10.

In order to allow setting a predetermined level of inerting in compartment 10, for example depending on the fire load of compartment 10 or at specific times or events, the control 11 shall be equipped with a control interface 38 through which a user can enter set values for the level of inerting to be set and/or maintained.

Preferably, at least one oxygen sensor 4 is located inside room 10 to measure continuously or at predefined times or events the oxygen content in the room air atmosphere of room 10. The oxygen measurement recorded by this sensor 4 can be fed to control 11 via a signal line 39. It is conceivable that an aspiration system may be used, in which a continuously representative portion of the room air is sucked in through a (not explicitly shown) piping or duct system and these portions are fed to the oxygen sensor 4. However, it is also conceivable to place at least one oxygen sensor 4 directly inside room 10.

As indicated above, in the preferred embodiment of the device of the invention, the inert gas is stored in liquid form in container 1. The container 1 is preferably designed as a double-walled refrigerator tank for permanent thermal insulation. To this end, container 1 may have an inner container 36 and a supporting outer container 24. The inner container 36 is made, for example, of cold-rolled Cr-Ni steel, while structural steel etc. is suitable as a material for the outer container 24. The space between the inner container 36 and the outer container 32 may be lined with perlite and additionally insulated by a vacuum. This allows for particularly good thermal insulation.

To allow the vacuum in the space between the inner tank 36 and the outer tank 24 to be renewed or reset if necessary, tank 1 shall have a vacuum connection 18 to which, for example, appropriate vacuum pumps can be connected.

The cooling tank used in the preferred embodiment of the solution of the invention is designed so that even when tank 1 is filled with liquid inert gas, the pressure in the inner tank 36 remains constant, so that even during refuelling the inert gas can be easily removed in liquid form via the liquid gas line 8. To fill the tank 1 itself, for example, a tanker pumps deep-cold inert gas through a filling port 28 into a filling port 34 The filling port 34 is connected via valves 29 to 32 to the inner tank 36 of the inert gas port 1. During the filling of tank 1 a flow gas connection or flow gas connection 33 is also possible via the flow gas port 33

As the evaporator 16 is located inside the enclosed space 10 in the embodiment shown in Figure 1, the evaporator 16 extracts all the heat required to evaporate the inert gas 37 supplied to the evaporator 16 in liquid form directly from the enclosed space atmosphere 10. As indicated above, the resulting cooling effect can be used to cool the enclosed space atmosphere 10 accordingly. This cooling effect can, in particular when room 10 is to be cooled permanently (cooling storage), or when room 10 is to be cooled over a longer period, in particular by the waste heat generated by electronic equipment, etc., which must be used to reduce the cooling effect (cooling) used for the cooling of the enclosed space, and in particular the operating costs of the entire air conditioning system.

The cooling effect used to cool the room air atmosphere of room 10 occurs in particular when inert gas is introduced into the room air atmosphere of room 10 in order to set and/or maintain a certain level of inertisation there, in particular when thermal energy is withdrawn from the room air atmosphere of room 10 and the room air atmosphere of room 10 is cooled accordingly.

As an additional option, which has also been implemented in the embodiment shown in Figure 1, an additional evaporator 20 may be provided in addition to the evaporator 16 located inside chamber 10 but outside chamber 10. This additional evaporator 20 is connected in preference to the refrigeration tank 1 by a line 46 and the additional evaporator 20 is used in preference to evaporate the inert gas taken from tank 1 by line 46 if necessary. The amount of inert gas supplied to the additional evaporator 20 can be regulated by a valve 19 located outside chamber 46 by pre-conditioning this valve 19 by the controller 11.

The inert gas evaporated in the further evaporator 20 can also be introduced, at least in part, for example, through the exhaust nozzles 2 into the enclosed space 10 in order to, for example, set or maintain a certain level of inertisation in the ambient air of the enclosed space 10. As shown, the output of the further evaporator 20 is connected to the line 3 and the exhaust nozzles 2 located inside the space 10 via a valve 21 operated as a three-way valve. In addition, the output of the further evaporator 20 can also be connected to an inert gas extraction connection 44 to allow the user of the container 1 to extract the inert gas from the inlet gas outside the space 10.

By providing the additional evaporator 20 located outside room 10 and thus not drawing any heat from the room air atmosphere during operation (i.e. evaporation of inert gas), it is possible to set up or maintain a permanent evaporation in room 10 even when cooling of room 10 by evaporation heat is not or no longer desirable. By using control 11 to control the corresponding valves 9 and 19, which are connected to the evaporator 16 located inside room 10 on the one hand and the additional evaporator 20 located outside the room on the other hand to the container 10 located inside the room, it is possible to either introduce the exhaust gas into the enclosed room by means of a 10 cm ventilation or by a specific means to either drain or maintain the exhaust gas in the room at the required level of evaporation or to heat the exhaust gas inside the room.

In Fig. 2 a second preferred embodiment of the solution of the invention is shown in a schematic representation. This embodiment differs from the one shown in Fig. 1 in that no evaporator is now provided inside chamber 10. Rather, an evaporator 16 is used, connected via the liquid gas line 8 to the inert gas tank 1 and located outside chamber 10, as is the other evaporator 20. In the liquid gas line 8 to the evaporator 16 the valve 9 is provided, which can be connected via the controller 11 to provide a controlled flow of the evaporator 16 to the inert gas tank 1 37 in a controlled manner.

The inert gas (liquid) supplied to evaporator 16 via the LPG line 8 is evaporated in evaporator 16 and then supplied via line 3 to the exhaust nozzles 2 located inside chamber 10.

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In order to extract the amount of air from the room air atmosphere necessary for heating the evaporator 16, the heat exchanger system of the evaporator 16 has an air duct system 22, 23 The air duct system includes a hot air line 22 through which, if necessary, a partial amount of the room air is sucked in, for example by means of a pump device 12, and fed to the evaporator 16 or to the heat exchanger of the evaporator 16.

The volume of room air supplied to the heat exchanger of the evaporator 16 can be adjusted in a regular manner by means of control 11 to the effect that control 11 sends appropriate control signals to the pump unit 12 via a control line 41 so that the flow rate and, if necessary, the flow direction of the pump unit 12 can be adjusted. In this case, it is conceivable that control 11 will adjust the flow rate of the pump unit 12 depending, for example, on a set operating temperature of the evaporator 16 and the average freezing temperature of the evaporator 16 or of the heat exchanger of the evaporator 16. In this case, a heat transfer value (in the direction of the evaporator) should be set at the same temperature as the evaporator 16 or at the evaporator 16 in the direction of the evaporator. If a continuous value is not provided for the flow rate of the evaporator 11 or 16 in the control unit, the flow rate of the evaporator 16 or the evaporator 16 should be set at the specified operating temperature. If the temperature is set at a set operating temperature, the flow rate of the evaporator 16 or the evaporator 16 should be set at a constant value.

After heat transfer from the volume of room air to the inert gas 37 supplied to the evaporator 16 (and to be liquefied) has taken place in the heat exchanger 16 of the evaporator, the volume of air thus cooled is fed back to the ambient air atmosphere of the enclosed room 10 via a cold air line 23 belonging to the air duct system.

The embodiment of the solution of the invention shown in Figure 2 allows the cooling effect of evaporation of the inert gas 37 to be used to cool the ambient air of the enclosed room 10 in a controlled manner. In particular, it is possible to adjust the rate of flow or flow of the pump equipment 12 by means of controller 11 by means of a signal transmitted by the control line 41. By adjusting the rate of flow or flow of the pump equipment 12 the amount of air flowing through the heat exchanger 16 per unit time and to heat the space to be evaporated and the space to be introduced by means of controller 10 can be adjusted. It is therefore apparent that when the pump equipment 12 is used, the flow rate or flow of the pump equipment 12 must be adjusted in such a way that the flow of the exhaust gas 16 per unit time is reduced by the gas flow rate of the evaporator 16 per unit time and by the heat exchanger 16 per unit time.

As described in the first embodiment with reference to Figure 1, the second embodiment also includes an additional evaporator 20 operating separately from the evaporator 16 and connected to the inert gas reservoir 1 via line 46; the additional evaporator 20 is designed to evaporate the inert gas 37 supplied via line 46 without extracting evaporative heat from the room air atmosphere of room 10.

A third preferred embodiment of the solution of the invention is shown in Figure 3 and is essentially the same as that shown in Figure 2, except that the heat exchanger attached to the evaporator 16 is heated only indirectly by the ambient air of the enclosed room 10.

The third preferred embodiment is to operate the heat exchanger of evaporator 16 (as the cooling medium) with a liquid heat exchanger medium 45. The heat exchanger medium 45 is stored in a heat exchanger tank 15. To allow heat transfer from the heat exchanger medium 45 to the inert gas to be evaporated and introduced into the chamber 10 in evaporator 16, two connections of the heat exchanger of evaporator 16 are connected to the heat exchanger tank 15 by a supply line and a drain.

A pump unit 13 controlled by a control line 42 by means of a control unit 11 can thus supply at least part of the heat exchanger 45 stored in the heat exchanger tank 15 to the heat exchanger tank 16 as cooling medium. The heat exchanger 45 fed to the heat exchanger tank 16 passes through the heat exchanger tank 16 and releases thermal energy to the inert gas to be evaporated and heated in the evaporator. The heat exchanger 45 released in the heat exchanger tank 16 is then fed back to the heat exchanger tank 15.

The system shown in Figure 3 has an additional heat exchanger 17 through which a part of the room air is passed on the one hand and the heat exchanger medium 45 stored in the heat exchanger tank 15 on the other. In particular, the additional heat exchanger 17 is connected to room 10 via an air duct system 22, 23 As in the case of the system shown in Figure 2, the air duct system has a hot air 22 conduit, which, if necessary, can be used by, for example, the pump unit 12 to suck in a part of the room air and supply it to the additional heat exchanger 17.

The volume of room air supplied to the further heat exchanger 17 can be adjusted in a controlled manner by means of control 11. To this end, control 11 sends appropriate control signals to pump 12 via control line 41 so that the conveyor rate and, if necessary, the conveyor direction of the pump 12 can be adjusted.

In this case, at least a temperature sensor 5 should be provided inside chamber 10 to measure the actual temperature of chamber 10 continuously or at specified times or events, and the temperature measured can then be transmitted to control 11 which compares the actual temperature with a specified set value and adjusts the rate of discharge of the pump unit 12 accordingly.

To ensure that heat transfer from the air in the room's atmosphere through the pump unit 12 can take place in the further heat exchanger 17, two connections of the further heat exchanger 17 are connected to the heat exchanger tank 15 by a supply line and a drain. By means of a pump unit 14 controlled by the controller 11 via a control line 43, at least part of the heat exchanger medium 45 stored in the heat exchanger tank 15 can then be cooled accordingly when the evaporator 16 is running, and the further heat exchanger 17 is fed back as the heating medium. The further heat exchanger 17 is fed through the further heat exchanger 17 and further heat is absorbed from the heat exchanger 15 while the heat transfer medium 17 is transferred to the further heat exchanger 15 in the further heat exchanger 15 is blocked.

After heat transfer from the supply air to the supply heat exchanger medium 45 has taken place in the further heat exchanger 17, the thus cooled air is returned to the ambient air atmosphere of the enclosed room 10 via the cold air line 23 of the air duct system.

The embodiment of the solution of the invention shown in Figure 3 allows the cooling effect of evaporation of the inert gas 37 to be used indirectly to cool down the ambient air of the enclosed room 10 in a controlled manner. In particular, it is possible to adjust the rate or the power of the pump equipment 12 by means of control 11 by transmitting a signal via the control line 41. By adjusting the rate or power of the pump equipment 12, the amount of air flowing through the additional heat exchanger 17 per unit of time used to cool down the ambient air of room 10 can be adjusted.

On the other hand, the embodiment shown in Figure 3 also allows the transfer rate or transfer power of pumps 13 and 14 to be set via control 11 by transmitting corresponding signals via control lines 42 and 43. By regulating the transfer rate or transfer power of the respective pumps 13, 14 the amount of heat exchanger medium 45 flowing through the heat exchanger 16 or other heat exchanger 17 per unit of time and used to heat the inert gas to be introduced into room 10 or to cool the room air atmosphere of room 10 can be set.

By using a heat exchanger medium 45 with a sufficiently high heat capacity, the heat exchanger medium stored in the heat exchanger tank 15 can be used as a cooling or heat reservoir to independently supply thermal energy to the evaporator 16 or to remove thermal energy from the room air if required.

The embodiment shown in Figure 3 may, as in the system shown in Figure 1 or Figure 2, be equipped with an additional evaporator 20 located outside compartment 10, in addition to evaporator 16; this additional evaporator 20 is connected in a preferred way by a line 46 to the tank 1 used as a refrigerating tank; the additional evaporator 20 is used in a preferred way to evaporate, if necessary, a quantity of inert gas extracted from tank 1 by line 46; the quantity of inert gas supplied to the further evaporator 20 can be regulated by the valve 19 attached to the cylinder 46 by attaching this valve 19 to the control unit 11 accordingly.

In the case of the system shown in Figure 3, the inert gas evaporated in the further evaporator 20 can also be introduced at least partially, for example, through the exhaust nozzles 2 into the enclosed space 10 in order to establish or maintain a certain level of inertisation in the ambient air of the enclosed space 10.

The preferred embodiments of the solution of the invention shown in the drawings also include a temperature measuring device 5 for measuring the temperature of the ambient air of the enclosed room 10 and an oxygen measuring device 4 for measuring the oxygen content of the ambient air of room 10. This temperature measuring device 5 enables the actual temperature of the enclosed room 10 to be determined continuously or at specified times and/or events.

In the embodiment shown in Fig. 1, the control 11 is preferably designed to control both valves 9 and 21 and an air conditioner (not shown) depending on the measured actual temperature and a specified operating temperature and on the measured oxygen content and a specified inerting level. The valves 9 and 21 control both the amount of inert gas to be supplied to room 10 and the heat generated by the evaporation of the inert gas to be supplied from the room air. If the cooling effect of the gas injected during the evaporation is not absorbed sufficiently to maintain a temperature appropriate to the temperature of the room 10 or 11 above the ambient temperature, the controller is set to operate at the controlled temperature.

On the other hand, it is preferable, in the embodiment shown in Fig. 2, to have the control 11 designed to control both the two valves 9, 21 and the pump unit 12 and an air conditioner (not shown), depending on the actual temperature measured and a specified set temperature, and depending on the oxygen content measured and a specified inerting level. The over-valve 9, 21 adjusts the amount of inert gas to be supplied to room 10 on the one hand, and the heat to be supplied to the room atmosphere by the conveyors of the pump unit 12 on the other. If the exhaust is provided with a suitable ventilator, the air conditioner will not be able to maintain a temperature of 10 or above the specified temperature in the room.

In the embodiment shown in Fig. 3, the control 11 is preferably designed to control both valve 9 and pumps 12 to 14 and an air conditioner (not shown) depending on the measured actual temperature and a specified set temperature and on the measured oxygen content and a specified inerting level. The valve 9 sets the amount of inert gas to be transferred to room 10. The heat output to the evaporator 16 is set by the transfer rate of the pump 13 and the heat output to the air atmosphere to be removed by the pumps 12 and 14. If the heat output is not controlled further in accordance with the specified temperature target, the air conditioner will not be able to maintain a temperature in the room.

The equipment shown in the drawings is not only suitable for preventive fire protection, whereby the flammability of the goods stored in the enclosed room 10 is reduced by preferably permanent reduction of the oxygen content in the ambient air, but it is also conceivable that in the event of a fire or if necessary the oxygen content of the ambient air can be further reduced to a certain level of complete inertisation by regularly supplying the ambient air with inert gas.

The setting (and maintaining) of the level of full inertisation may be done, for example, for the purpose of firefighting. In this case, it is preferable that the plant also has a fire detection device 6 to measure a fire signal in the atmosphere of the enclosed room 10. However, it is also conceivable that the reduction to the level of full inertisation depends on the goods stored in the enclosed room 10 and in particular their ignition behaviour.

The invention is not limited to the embodiments shown in the drawings.

List of reference marks

1Tank for storage of liquefied inert gas2Exhaust nozzles3Direct4Oxygen sensor5Temperature sensor6Fire core size sensor8Liquid gas line9Driver valve10Closed room11Control12Pump13Pump14Pump15Heat exchanger tank16Heat exchanger/vaporiser17Additional heat exchanger18Vapour pump connection19Driver valve20Additional evaporator21Threeway valve/discharge valve22Air duct system/heat air duct23Air duct air system/cold air duct24External container of the containerFull container connection29Storage heater30VentilatorFull container of the container31Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container41Full container of the container (Full container of the container) (Full container) of the container41Full container of the container (Full container) of the container (Full container) of the container (Full container) of the container (Full container) of the container (Full container) of the container (Full container) of the container (Full container) of the container (

Claims (24)

1. A method for preventing fires and extinguishing fires in enclosed spaces (10) in which the internal air atmosphere is not permitted to exceed a predefined temperature value, wherein the method comprises the following method steps:

   a) providing a liquefied inert gas, in particular nitrogen, in a container (1);

   b) supplying at least a portion of the provided inert gas to a vaporizer (16) and being vaporized in same; and

   c) the regulated supplying of the inert gas vaporized in the vaporizer (16) to the internal air atmosphere of the enclosed space (10) such that the oxygen content in the atmosphere of the enclosed space (10) either drops to a specific inertization level and is maintained at same or is maintained at a specific, preset inertization level, wherein the heat energy needed to vaporize the liquid inert gas in the vaporizer (16) is extracted from the internal air atmosphere of the enclosed space (10).
2. The method according to claim 1, wherein the inert gas provided is vaporized within the enclosed space (10), and wherein the inert gas is supplied in liquid form to a vaporizer (16) disposed within said space (10) prior to the method step of vaporizing.
3. The method according to claim 1, wherein the inert gas provided is vaporized external the enclosed space (10), and wherein at least a portion of the heat energy needed to vaporize the inert gas is extracted from the internal air atmosphere of the enclosed space (10) by heat conduction.
4. The method according to claim 3, wherein the adjustable amount of heat energy extracted from the internal air atmosphere of the enclosed space (10) needed to vaporize the inert gas can be regulated by being able to set the heat conductivity of a heat conductor (45) used to extract the required amount of energy as a function of the actual current temperature within the enclosed space (10) and/or a predefinable target temperature.
5. The method according to claim 3, wherein a unit cooler (16) is used to vaporize the at least portion of the inert gas provided, and wherein the method further comprises the following method steps:

   b1) the vaporizer (16) or a heat exchanger allocated to said vaporizer (16) supplies air from the internal air atmosphere of the enclosed space (10) as heated air, preferably in regulated manner, at least during the vaporization of the inert gas;

   b2) the heat energy needed to vaporize the inert gas is at least partly extracted by heat conduction from the air supplied the vaporizer (16) or the heat exchanger as heated air, whereby the air supplied as heated air cools; and

   b3) the cooled air is fed back again into space (10).
6. The method according to claim 5, wherein the amount of the air supplied as heated air to the vaporizer (16) or the heat exchanger is adjustable as a function of the actual current temperature within the enclosed space (10) and/or a predefinable target temperature.
7. The method according to any one of the preceding claims, wherein the method step c) further comprises the following method steps:

   c1) measuring the oxygen content in the enclosed space (10); and

   c2) supplying the inert gas vaporized in the vaporizer (16) as a function of the measured oxygen value of the internal air atmosphere of the enclosed space (10) in order to maintain the oxygen content in the atmosphere of the enclosed space (10) at a specific inertization level.
8. The method according to any one of the preceding claims, wherein the specific inertization level is a basic inertization level, and wherein the method further comprises the following method step subsequent method step c):

   d) in the event of a fire or when otherwise needed, the oxygen content in the internal air atmosphere is further lowered to a specific full inertization level by the regulated supplying of inert gas into the internal air atmosphere.
9. The method according to claim 8, wherein a detector (6) for fire characteristics identifies whether a fire has broken out in the enclosed space (10).
10. The method according to claim 9, wherein the lowering to the full inertization level in method step c) is subject to a fire characteristic value measured by the detector (6).
11. The method according to claim 8 or 9, wherein the lowering to the full inertization level in method step d) is subject to the merchandise stored in enclosed space (10), and in particular its ignition behavior.
12. The method according to any one of claims 8 to 11, wherein the inert gas supplied in method step d) is provided in the container (1) preferably configured as a cooling tank and vaporized with the vaporizer (16).
13. A device for realizing the method according to any one of claims 1 to 12, wherein the device comprises the following:

    - an oxygen-measuring mechanism (4) for measuring the oxygen content in the internal air atmosphere of the enclosed space (10);

    - a system for the regulated discharging of inert gas into the internal air atmosphere of the enclosed space (10), wherein the system comprises a container (1) preferably configured as a cooling tank for the provision and storage of the inert gas in liquefied form and a vaporizer (16) connected to said container (1) for vaporizing at least a portion of the inert gas provided in the container (1) and discharging the vaporized inert gas into the internal air atmosphere of the enclosed space (10); and

    - a controller (11) designed to control the system providing the regulated discharging of the inert gas subject to the measured oxygen content such that the oxygen content in the atmosphere of the enclosed space (10) either drops to a specific inertization level and is maintained at same or is maintained at a specific preset inertization level,

    wherein the vaporizer (16) is configured to extract the heat energy needed to vaporize the fluid inert gas from the internal air atmosphere of the enclosed space (10).
14. The device according to claim 13, wherein the vaporizer (16) is a unit cooler (16) disposed within the enclosed space (10).
15. The device according to claim 13, wherein the vaporizer (16) is a unit cooler (16) disposed external the enclosed space (10), and wherein the system for the regulated discharging of inert gas into the internal air atmosphere of the enclosed space (10) further comprises a heat exchange device (16, 17) which provides the heat transfer from the internal air atmosphere of the enclosed space (10) to the inert gas to be vaporized in the vaporizer (16).
16. The device according to claim 15, further comprising a temperature-measuring mechanism (5) for measuring the temperature of the internal air atmosphere of the enclosed space (10), and wherein the heat exchange device (16, 17) comprises a heat exchanger (45) to transfer heat energy from the internal air atmosphere to the inert gas to be vaporized in the vaporizer (16), the efficiency ratio of same being adjustable in terms of the first law of thermodynamics by controller (11) as a function of the measured temperature and/or a predefinable target temperature.
17. The device according to claim 15, wherein the vaporizer (16) is a unit cooler (16), and wherein inert gas to be supplied the enclosed space (10) is used as the medium to be heated and a portion of the air from the internal air atmosphere is used as the medium to be cooled in the heat exchange device (16, 17).
18. The device according to claim 17, wherein the heat exchange device (16, 17) is connected to the enclosed space (10) by means of an air duct system (22, 23) for the supplying and draining of air from the internal air atmosphere of the enclosed space (10), and wherein the air duct system (22, 23) comprises at least one hot air duct (22) and at least one cold air duct (23) of an air conditioning system used to air condition the enclosed space (10).
19. The device according to claim 17 or 18, further comprising a temperature-measuring mechanism (5) to measure the temperature of the internal air atmosphere within the enclosed space (10), and wherein the controller (11) is designed to set the amount of air supplied to the vaporizer (16) as the medium to be cooled as a function of the measured temperature and/or a predefinable target temperature.
20. The device according to any one of claims 15 to 19, wherein the heat exchange device (16, 17) is a component of an air conditioning system used to air condition the enclosed space (10).
21. The device according to claim 20, wherein the air conditioning system comprises a heat exchanger through which a portion of the air from the internal air atmosphere is routed in order to transfer thermal energy from the air to a cooling medium, and wherein the heat exchanger of the air conditioning system is connected upstream or downstream of the heat exchanger associated with the vaporizer (16).
22. The device according to any one of claims 13 to 21, further comprising a fire detection device (5) to measure a fire characteristic in the internal air atmosphere of the enclosed space (10).
23. Use of the device according to any one of claims 13 to 22 as fire prevention for an enclosed cold storage area, an IT room or other such similar space (10) in which the internal air atmosphere of same is not permitted to exceed a specific temperature value.
24. Use of the device according to any one of claims 13 to 22 as fire prevention for an enclosed switchgear cabinet or other such similar construction in which the internal air atmosphere of same is not permitted to exceed a specific temperature value.