EP1913979B1 - Inerting device with nitrogen generator - Google Patents

Description

The present invention relates to an inerting device for setting and maintaining predeterminable inertization levels in a protected space to be monitored, wherein the inerting device comprises a controllable inert gas system for providing inert gas, a first supply pipe system connected to the inert gas system, which can be connected to the protective space, around that provided by the inert gas system Inert gas supply to the shelter, and having a control unit which is adapted to control the inert gas system such that a certain specifiable inerting level is set and held in the shelter, the inert gas system having a compressed air source connected to a nitrogen generator to oxygen from the with the Compress compressed air source supplied compressed air and provide nitrogen-enriched air at a first output of the nitrogen generator, and wherein the nitrogen generator provided with Nitrogen-enriched air via the first output of the nitrogen generator can be supplied as an inert gas to the first supply pipe system.

Such an inerting device is basically known from the prior art, for example EP 1 683 548 A1 , For example, in the German patent DE 198 11 851 C2 an inerting device for reducing the risk and extinguishing fires in enclosed spaces described. The known system is designed, the oxygen content in an enclosed space (hereinafter "shelter" called) on a to reduce the level of pre-fixable ground inerting levels and, in the event of a fire, to further reduce the oxygen content rapidly to a certain level of full inertisation, thereby enabling effective extinguishment of a fire with the least possible storage capacity for inert gas cylinders. For this purpose, the known device comprises an inert gas system which can be controlled by means of a control unit and also a feed pipe system connected to the inert gas system and the protective space, via which the inert gas provided by the inert gas system is supplied to the protective space. As an inert gas is either a steel cylinder battery in which the inert gas is stored compressed, a system for generating inert gases or a combination of both solutions in question.

In the inerting of the type mentioned is a facility to reduce the risk and extinguish fires in the protected area to be monitored, with a permanent inerting of the shelter for fire prevention and fire fighting is used. The operation of the inerting device is based on the knowledge that in closed rooms the risk of fire can be counteracted by the fact that the oxygen concentration in the affected area is normally lowered permanently to a value of, for example, about 12% by volume. At this oxygen concentration, most flammable materials can no longer burn. The main areas of use are in particular IT areas, electrical switch and distribution rooms, enclosed facilities as well as storage areas with high-quality assets.

The prevention or extinguishing effect resulting from the inertization process is based on the principle of oxygen displacement. The normal ambient air is known to be 21% by volume of oxygen, 78% by volume of nitrogen and 1% by volume of other gases. To effectively reduce the risk of fire in a shelter, the concentration of oxygen in the room is reduced by introducing inert gas, such as nitrogen. With regard to fire extinguishment of most solids, it is known, for example, that a extinguishing effect starts when the oxygen content drops below 15% by volume. Depending on the combustible materials present in the shelter, further lowering of the oxygen content to, for example, 12 vol.% May be required. In other words, by continuously inerting the shelter at a so-called "basic inertization level" where the oxygen content in the room air is lowered below, for example, 15% by volume, the risk of fire in the shelter is also effectively reduced can be.

The term "base inertization level" as used herein generally refers to a reduced oxygen level in the room air of the shelter as compared to the oxygen level of the normal ambient air, although this reduced oxygen level does not in principle imply any endangerment to persons or animals from a medical point of view still be able to enter the shelter - under certain circumstances with certain precautionary measures. As already indicated, the setting of a basic inertization level, which, unlike the so-called "full inertization level", does not have to correspond to such a reduced oxygen content at which effective fire extinguishment already occurs, primarily to reduce the risk of fire in the shelter to reduce. The basic inerting level corresponds, depending on the circumstances of the individual case, to an oxygen content of, for example, 13% by volume to 15% by volume.

On the other hand, the term "full inertization level" is to be understood as meaning a further reduced oxygen content in comparison to the oxygen content of the basic inertization level, in which the flammability of most materials has already been reduced to such an extent that they can no longer be ignited. Depending on the fire load present in the affected shelter, the full inertization level is generally 11% by volume to 12% by volume oxygen concentration.

Although the reduced oxygen content in the room air of the protected room corresponding to the basic inerting level in principle does not endanger persons and animals so that they can enter the shelter at least for a short time without major complications, for example without respiratory protection, they are permanently inertized at a basic inerting level Certain nationally prescribed safety measures must be taken into account, since in principle a stay in a reduced oxygen atmosphere can lead to an oxygen deficiency, which may have physiological effects on the human organism. These safety measures are specified in the respective national regulations and depend in particular on the amount of reduced oxygen content corresponding to the basic inerting level.

Table 1 below shows these effects on the human organism and the flammability of materials.

In order to meet in a simple and in particular easy to implement the safety measures imposed with respect to the accessibility of the shelter by the national regulations, which become increasingly stringent with decrease in the oxygen content in the air of the shelter, it would be conceivable for the purpose and for the period of Commitment to increase the permanent inerting of the shelter from the baseline level to a level of accessibility where the required safety requirements are lower and can be met without major inconvenience. <b><u> Table 1 </ u></b> Oxygen content in the shelter Impact on the human organism Impact on the combustibility of materials 8 vol.% risk of death Non-flammable 10 vol.% Judgment and pain decrease Non-flammable 12 vol.% Fatigue, increase in tidal volume and pulse Flame retardant 15 vol.% None Flame retardant 21 vol.% None None

For example, it would be useful to have a shelter that would normally be at a basic inerting level of e.g. 13.8 to 14.5% by volume oxygen content in which, according to Table 1, an effective fire suppression can already be achieved, in the case of the inspection, for example for maintenance purposes, to a walkability level of e.g. Increase 15 to 17 vol .-% oxygen content.

From a medical point of view, a temporary stay in an oxygen atmosphere reduced to this level of accessibility is safe for all persons with no cardiovascular, vascular or respiratory diseases, so that the respective national regulations have no or only slight additional safety measures demand.

Usually the lifting of the inertisation level set in the shelter takes place from the basic inertisation level to the accessibility level by a corresponding one Control of the inert gas system. In this case, it is particularly useful for economic reasons, during the inspection of the shelter to keep the set in the shelter inerting (permanently with a corresponding control range) permanently at the Begehbarkeitsniveau to the after the inspection of the shelter for re-setting the Grundinertisierungsniveaus in the shelter to keep the amount of inert gas to be introduced as small as possible. For this reason, the inert gas system should also produce or provide inert gas during the period of inspection of the protective space, so that the inert gas is supplied to the shelter in order to maintain the inerting level there (possibly with a certain control range) at the accessibility level.

It should be noted that the term "accessibility level" as used herein means a reduced oxygen content in the ambient air of the shelter as compared to the oxygen content of the normal ambient air, in which the respective national regulations for an inspection of the shelter are none or only slight require additional security measures. The walkability level usually corresponds to an oxygen content in the room air that is higher than at a basic inerting level.

The present invention is based on the object of developing an inerting device of the type mentioned in such a way that it can be reliably ensured that the inerting level can be quickly raised to a walkability level in a permanently inertized shelter without the need for additional large-scale structural measures ,

In general terms, the present invention has for its object to provide an inerting device of the type mentioned, with which a set in a protected space to be monitored inerting can be set and / or maintained in a reliable, the switching of the set in the shelter inerting, for example between a basic or full inertisation level and a level of accessibility, can be carried out as quickly as possible, without the need for major structural measures.

These objects are achieved with an inerting device of the type mentioned above in that the inerting device further comprises a second supply pipe system connected to the inert gas system, which can be connected to the protective space, wherein the oxygen separated from the compressed air from the nitrogen generator oxygen-enriched air can be supplied to the second supply pipe system via a second outlet of the nitrogen generator in order to set and / or maintain a certain inerting level in the shelter.

The use of nitrogen generators in inerting devices is known per se. The nitrogen generator is a system that can be used, for example, to generate nitrogen-enriched air from normal ambient air. This is a gas separation system whose function is based, for example, on gas separation membranes. The nitrogen generator is designed for the separation of oxygen from the ambient air. To build an operable gas separation system based on a nitrogen generator, a compressed air network or at least a compressor is required which produces the predetermined capacity for the nitrogen generator. The principle of action of the nitrogen generator is based on the fact that in the membrane system provided in the nitrogen generator, the various components contained in the compressed air supplied to the nitrogen generator (oxygen, nitrogen, noble gases, etc.) diffuse at different speeds through hollow-fiber membranes in accordance with their molecular structure. Nitrogen with a low degree of diffusion penetrates the hollow-fiber membranes very slowly and accumulates in this way as it flows through the hollow fiber.

For example, when a membrane technique is used in the nitrogen generator, the general discovery is that different gases diffuse through materials at different rates. In the case of the nitrogen generator, in this case the different diffusion rates of the main components of the air, namely nitrogen, oxygen and water vapor, are used technically to produce a nitrogen stream or a nitrogen-enriched air. In particular, for the technical realization of a membrane-based nitrogen generator, a separation material is applied to the outer surfaces of hollow-fiber membranes, through which water vapor and oxygen diffuse very well. The nitrogen, however, has only a low diffusion rate for this separation material. If the thus prepared hollow fiber is traversed inside by air, water vapor and oxygen quickly diffuse through the hollow fiber wall to the outside, while the nitrogen is largely maintained in the fiber interior, so that during the passage through the hollow fiber, a strong concentration of nitrogen takes place. The effectiveness of this separation process is essentially dependent on the flow rate in the fiber and the pressure difference across the Hohlfaserwandung away. With decreasing flow velocity and / or higher pressure difference between interior and outside of the hollow fiber membrane increases the purity of the resulting nitrogen stream.

If, on the other hand, the PSA technology is used, for example, in the nitrogen generator, different binding rates of the atmospheric oxygen and atmospheric nitrogen on specially treated activated carbon are utilized. In this case, the structure of the activated carbon used is changed so that an extremely large surface with a large number of micro and submicropores (d <1 nm) is present. At this pore size, the oxygen molecules of the air diffuse into the pores much faster than the nitrogen molecules, so that the air in the vicinity of the activated carbon enriches with nitrogen.

According to the invention, the usually discharged into the ambient air exhaust air of the nitrogen generator, which consist essentially of oxygen-enriched air used to adjust the oxygen concentration in the shelter with this exhaust air.

The achievable with the inventive solution advantages are obvious. Thus, in the inerting device according to the invention, for example, the lifting of a full or basic inertisation level set in the shelter can be converted to a walkability level within a very short time. Further, since raising the full or basic inertization level set in the shelter to the walkability level by introducing the oxygen-enriched air, it is possible to raise the oxygen content in the shelter by introducing a relatively small amount of gas. This is particularly advantageous if the air exchange rate in the shelter should be kept at a low value. Namely, if not the oxygen-enriched air but, for example, "normal" ambient air, i. Air with an oxygen content of 21% by volume, which is used to increase the oxygen content in the shelter, requires a significantly higher amount of gas compared to the oxygen-enriched air.

In particular, in the case of the present invention it is preferably further provided that the second supply pipe system discharges into the first supply pipe system and is thus connectable to the protection space via the first supply pipe system, so that this first supply pipe system is used solely to adjust or set a certain inertization level in the shelter . to keep.

In order to be able to set and accurately maintain the predetermined steady inerting level in the protective space in the inerting device according to the present invention, it is preferably provided that the inerting device further includes a shutoff valve associated with the second supply pipe system and controllable via the control unit for interrupting by means of the second supply pipe system between the having second output of the nitrogen generator and the shelter space producible connection. As a controllable shut-off valve, for example, a corresponding controllable control valve or the like in question.

In a preferred further development of the inerting device according to the present invention, the inerting system further comprises a pressure storage tank for storing the oxygen-enriched air provided by the nitrogen generator, the control unit being adapted to associate with a so-called "oxygen pressure storage tank" and with the second one Supply pipe connected drive controllable pressure reducer in such a way to adjust or maintain a certain inerting in the shelter.

In a preferred realization of the last-mentioned embodiment of the inerting device, a pressure-dependent valve device is furthermore provided, which is open in a first predeterminable pressure range and allows the oxygen pressure-accumulator container to be filled with the oxygen-enriched air provided by the nitrogen generator.

In the following, preferred developments are given, which are applicable to the aforementioned embodiments of the inerting device according to the invention.

Thus, it would be conceivable, for example, that the inerting device furthermore has at least one shut-off valve which is assigned to the first supply pipe system and can be actuated via the control unit for interrupting the connection which can be produced by means of the first supply pipe system between the first outlet of the nitrogen generator and the protective space. With this controllable shut-off valve associated with the first supply pipe system, the nitrogen supply can thus be regulated. This is particularly advantageous with regard to maintaining a predefinable inertization level in the protection space, since in this case the amount of inert gas to be supplied to the protection space and / or the oxygen concentration of the inert gas is primarily dependent only on the air exchange rate of the inert gas Protective space depends and depending on the design of the shelter can assume a correspondingly low value.

In an advantageous further development of the inerting device according to the invention, although partially known from the state of the art, at least one oxygen detection device is provided for detecting the oxygen content in the room air of the protection space, the control unit being designed to control the amount of inert gas to be supplied to the protection space and / or or to adjust the oxygen concentration of the inert gas as a function of the measured in the room air of the shelter oxygen content, thus basically only the actually required to set or hold a certain inerting required in the shelter inert gas to the shelter. In particular, the provision of such an oxygen detection device ensures that the inerting levels to be set in the protective space can be set and maintained as accurately as possible by supplying a suitable inert gas quantity and / or a suitable fresh air or oxygen quantity. It would be conceivable here that the oxygen detection device continuously or at predeterminable times emits a corresponding signal to the corresponding control unit, as a result of which the inert gas system is correspondingly activated in order always to supply the protective space with the inertization level necessary for maintaining the inertization level set in the protection space.

It should be noted that the person skilled in the art recognizes that the term "holding the oxygen content at a certain inertization level" as used herein means maintaining the oxygen content at the inertization level with a certain control range, the control range preferably being a function of the Type of shelter (for example, depending on an applicable for the shelter air exchange rate or depending on the materials stored in the shelter) and / or depending on the type of inerting system used for use. Typically, such a control range is ± 0.2 vol%. Of course, other control range sizes are also conceivable.

In addition to the abovementioned continuous or regular measurement of the oxygen content, it is, however, also possible to maintain the oxygen content at the predeterminable specific inerting level as a function of a previously performed calculation, in which calculation certain design parameters of the protective space should be included, such as those applicable to the protective space air exchange rate, in particular the n50 value of the protection space, and / or the pressure difference between the protection space and the environment.

As an oxygen detection device, in particular an aspirative device offers itself here. In such a device, the room air in the protected space to be monitored is constantly taken representative air samples and fed to an oxygen detector, which emits a corresponding detection signal to the corresponding control unit.

In principle, it is conceivable to provide an ambient air compressor and an inert gas generator connected thereto as the inert gas system, the control unit being designed to control, for example, the air conveyor rate of the ambient air compressor such that the amount of inert gas supplied to the protective room by the inert gas system and / or the Oxygen concentration in the inert gas can be set to the appropriate value for setting and / or holding the first predetermined inerting. This preferred solution with regard to the inert gas system is characterized in particular by the fact that the inert gas system can generate the inert gas in situ, which eliminates the need, for example, to provide a pressure-cell battery in which the inert gas is stored in a compressed form.

In addition to this, it is of course also conceivable that the inert gas system further comprises an inert gas pressure storage container, wherein the control unit should be designed to control a controllable pressure reducer associated with the inert gas pressure accumulator tank and connected to the first supply pipe system in such a way as to provide that provided by the inert gas unit Set amount of inert gas to be supplied to the shelter space and / or the oxygen concentration in the inert gas to the value suitable for setting and / or maintaining the predeterminable inertization. The inert gas pressure storage container may be provided in combination with the aforementioned ambient air compressor and / or inert gas generator or else alone.

In a preferred further development of the last-mentioned embodiment, in which the inert gas system has a so-called "inert gas pressure storage container", it is provided that the inerting device further comprises a pressure-dependent valve device which opens in a first prescribable pressure range, for example between 1 and 4 bar is and a filling of the inert gas pressure storage tank with the inert gas system allowed.

As already indicated, the solution according to the invention is not limited to setting or maintaining the accessibility level in the shelter. Rather, the claimed inerting device is designed such that the predeterminable inerting level can be a Vollinertisierungsniveau, a Grundinertisierungsniveau or a walkability level.

Finally, in a preferred realization of the inerting device according to the invention, it is further provided that the inert gas system further comprises a bypass pipe system preferably connectable with the control unit via a shut-off valve which is connected on the one hand to a compressed air source and on the other hand to the first supply pipe system Compressed air source supplied compressed air to the shelter as fresh air, and thus to adjust the oxygen concentration in the shelter at a level which corresponds to be set in the shelter and / or held certain inerting. In this development, therefore, in addition to the oxygen-enriched air generated by the nitrogen generator, the compressed air provided by the compressed air source can be used to increase the oxygen content in the shelter.

The achievable with this development advantages are obvious: Accordingly, the protective space supplied inert gas and the oxygen concentration in the inert gas can be controlled in the inert gas system to the necessary for setting or holding the predetermined inerting in the shelter value, the inert gas system the controllable inert gas system, which is connected to the control unit via a shut-off valve bypass pipe system which is connected on the one hand to a compressed air source and on the other hand to the first supply pipe system, and the supply pipe system. Accordingly, in this development, the inert gas system has the function of providing both (ideally pure) inert gas and fresh air, so that the supply pipe system, which connects the inert gas system with the shelter, for the supply of pure inert gas, pure fresh air or a mixture thereof is used.

It should be noted that the term "compressed air" compressed air is to be understood in the broadest sense. In particular, the term "compressed air" but also compressed and oxygen-enriched air to be understood. The compressed air can either be stored in appropriate pressure vessels or generated locally with suitable compressor equipment. In addition, it should be noted that the term "compressed air", for example, fresh air is to be understood, is introduced by means of a suitable blower in the bypass pipe system. Since the introduced with a blower in the bypass pipe system air also has a higher pressure compared to the normal ambient air, so there is compressed air or compressed air.

Specifically, with the last-mentioned development of the solution according to the invention, the amount of inert gas supplied by the inert gas system and / or the oxygen concentration in the inert gas can be controlled on the one hand by a corresponding control of the inert gas system, with which the absolute amount of inert gas provided per unit time is controlled on the other hand by a corresponding control of the bypass pipe system associated with the shut-off valve, whereby the absolute, the protection space per unit time supplied fresh air amount is set.

In a preferred embodiment of the last-mentioned further development, it is provided that the compressed-air source has a pressure storage container for storing oxygen, oxygen-enriched air or compressed air, wherein the control unit is designed to control a controllable pressure reducer associated with the pressure storage container and connected to the first supply pipe system, to set or maintain a certain inerting level in the shelter. It should be noted that in this preferred embodiment, the pressure storage container can be provided either as a compressed air source itself or as a separate unit in addition to the compressed air source in the inerting. The accumulator tank is in an advantageous manner in fluid communication with the via the shut-off valve switchable bypass pipe system.

In the following, preferred embodiments of the inerting device according to the invention will be described in more detail with reference to the drawings.

Fig. 1:

eine schematische Ansicht einer ersten bevorzugten Ausführungsform der erfindungsgemäßen Inertisierungsvorrichtung;

Fig. 2:

eine schematische Ansicht einer zweiten bevorzugten Ausführungsform der erfindungsgemäßen Inertisierungsvorrichtung; und

Fig. 3:

eine schematische Ansicht einer dritten bevorzugten Ausführungsform der erfindungsgemäßen Inertisierungsvorrichtung.

Show it:

Fig. 1:

a schematic view of a first preferred embodiment of the inerting device according to the invention;

Fig. 2:

a schematic view of a second preferred embodiment of the inerting device according to the invention; and

3:

a schematic view of a third preferred embodiment of the inerting device according to the invention.

In Fig. 1 1 schematically shows a first preferred embodiment of the inerting device 1 according to the invention for setting and maintaining predeterminable inerting levels in a protected space 2 to be monitored. In essence, the inerting device 1 consists of an inert gas system, which in the illustrated embodiment has an ambient air compressor 10 and an inert gas or nitrogen generator 11 connected thereto. Furthermore, a control unit 12 is provided, which is designed to turn on / off via corresponding control signals the ambient air compressor 10 and / or the nitrogen generator 11. In this way, by means of the control unit 12 in the shelter 2, a predetermined inerting level can be set and maintained.

The inert gas generated by the inert gas system 10, 11 is supplied via a feed pipe system 20 ("first supply pipe system") to the protected space 2 to be monitored; Of course, however, several shelters may be connected to the supply pipe system 20. In detail, the supply of the inert gas provided with the inert gas system 10, 11 via corresponding outlet nozzles 51, which are arranged at a suitable location in the shelter 2.

At the in Fig. 1 illustrated preferred embodiment of the solution according to the invention, the inert gas, advantageously nitrogen, recovered locally from the ambient air. The inert gas generator or nitrogen generator 11 functions, for example, according to the known from the prior art membrane or PSA technology to produce nitrogen-enriched air with, for example, 90 vol .-% to 95 vol .-% nitrogen content. This nitrogen-enriched air is used in the Fig. 1 illustrated preferred embodiment as an inert gas, which is supplied to the shelter 2 via the supply pipe system 20.

Specifically, it is provided that the nitrogen generator 11 has an (not explicitly shown) air separation system to separate oxygen from the compressed air supplied with the compressed air source 10 compressed air and nitrogen-enriched air at a first output 11a of the nitrogen generator 11. In detail, it is provided that the nitrogen generator 11 provided by nitrogen and enriched Air via the first output 11a of the nitrogen generator 11 can be supplied as an inert gas to the first supply pipe system 20.

The inerting device 11 further has a second supply pipe system 30 connected to the inert gas system 10, 11, which can be connected to the protective space 2 via a shut-off valve 31 which can be activated by the control unit 12, the oxygen separated from the compressed air by the nitrogen generator 11 being oxygen-enriched air via a second output 11b of the nitrogen generator 11 to the second supply pipe system 30 can be supplied. The second supply pipe system 30 opens in the first supply pipe system 20 and is therefore connectable to the shelter 2 via the first supply pipe system 20. By a suitable control of the inert gas system 10, 11, the first supply pipe system 20 associated shut-off valve 21 and / or the second supply pipe system 30 associated shut-off valve 31, it is thus possible to quickly set in the shelter 2 a certain inerting and keep accurate.

In detail, it is provided that the control unit 12, depending on an example entered by the user in the control unit 12 inerting the inert gas system 10, 11 so controlled that the predetermined inerting is set and maintained in the shelter 2. The selection of the desired inerting levels on the control unit 12 can be carried out, for example, with a key switch or password-protected on a (not explicitly shown) control panel. Of course, however, it is also conceivable here that the selection of the inertization level takes place according to a predetermined sequence of events.

If, for example, the basic inerting level is selected at the control unit 12, which was determined in advance taking into account the characteristic values of the protection space 2, and if no inertization level has been set in the selection of the basic inertization level in the protection space 2, ie if there is a gas atmosphere in the protection space, which is substantially identical to the chemical composition of the ambient air, a shut-off valve 21 associated with the supply pipe system 20 is connected to the control unit 12 for direct forwarding of the inert gas provided by the inert gas system 10, 11 in the shelter 2. At the same time, the oxygen content in the protective space 2 is preferably continuously measured with the aid of an oxygen detection device 50. As shown, the oxygen sensing device 50 communicates with the control unit 12 so that the Control unit 12 basically has knowledge of the oxygen content set in the shelter 2.

If it is determined by measurement of the oxygen content in the shelter 2 that the Grundinertisierungsniveau was reached in the shelter 2, the control unit 12 outputs a corresponding signal to the inert gas system 10, 11 and / or to the shut-off valve 21 to turn off the further supply of inert gas. In the course of time, inert gas escapes through certain leaks, so that the oxygen concentration in the indoor air atmosphere increases. When the inertization level has moved away from the set point by more than a predetermined amount, the control unit 12 sends a corresponding signal to the inert gas system 10, 11 and / or to the shut-off valve 21 to reactivate the supply of inert gas.

Fig. 2 shows a schematic view of a second preferred embodiment of the inertization device according to the invention 1. The in Fig. 2 shown system differs from the embodiment according to Fig. 1 in that additionally an accumulator tank 32 is provided for storing the oxygen-enriched air provided by the nitrogen generator 11, the control unit 12 being adapted to control a controllable pressure reducer 33 associated with the oxygen accumulator tank 32 and connected to the second supply pipe system 30, to set the amount of inert gas to be supplied to the shelter 2 from the inert gas equipment 10, 11 and / or the oxygen concentration in the inert gas to the value suitable for setting and / or maintaining the determined inertization level.

Furthermore, a pressure-dependent valve device 34 is provided, which is open in a first predeterminable pressure range and allows a filling of the oxygen pressure storage container 32 with the nitrogen generator 11 provided and oxygen-enriched air.

Furthermore, the inerting device 1 according to FIG Fig. 2 an accumulator tank 22 serving to store, if necessary, the nitrogen-enriched air supplied from the nitrogen generator 11. The control unit 12 is designed to correspondingly control a valve system 23, 24 associated with the pressure accumulator tank 22 and connected to the first supply pipe system 20 via the controllable three-way valve 21 in order to connect the pressure accumulator tank 22 to the first supply pipe system 20 as needed, so that the provided in the accumulator tank 22 and with Nitrogen-enriched air can be supplied to the shelter 2. When the nitrogen-enriched air provided in the accumulator tank 22 is supplied to the shelter 2, it is possible to shut off or throttle the nitrogen generator 11 at least temporarily, which lowers the running cost of the plant. Preferably, the controller 12 and the valve system 23, 24 should be designed so that from the accumulator tank 22, a sufficient amount of nitrogen-enriched air can be supplied to the shelter to hold or set in the shelter 2, the certain inerting.

The pressure accumulator tank 22 associated valve system 23, 24 includes a pressure-dependent valve device 24 which is open in a first predetermined pressure range and allows filling of the pressure storage container 22 with the nitrogen generator 11 provided and enriched with nitrogen air. Furthermore, the valve system has a controllable by the control three-way valve 24. This three-way valve 24, together with the three-way valve 21, allows an outlet pipe system connected to the outside atmosphere, the accumulator tank 22, and the first supply pipe system 20 to be connected to each other as necessary

Fig. 3 shows a schematic view of another embodiment of the inertization device according to the invention 1. In this embodiment, a bypass pipe system 40 on the one hand and on the other hand a second supply pipe system 30 between the second output 11b of the nitrogen generator 11 and the first supply pipe system 20 is provided. The bypass pipe system 40 connects the output of the compressed air source 10 to the supply pipe system 20. About this bypass pipe system 40, the supply pipe 20 and thus the shelter 2 directly supplied from the compressed air source 10 compressed air can be supplied as fresh air as needed. A direct supply of fresh air in the protection space 2 may be required if the inertization level set in the protection space 2 corresponds to an oxygen concentration which is lower than the oxygen concentration of an inertization level to be set in the protection space 2. This would be the case, for example, if too much inert gas was introduced accidentally or for other reasons when setting the basic inerting level in the shelter 2. On the other hand, a fresh air supply is also necessary if as quickly as possible in the shelter 2 already set there continuous annealing must be at least partially canceled, as is required, for example, in the case of the inspection of the shelter 2.

Generally speaking, with the inert gas system according to this in Fig. 3 1, the amount of inert gas to be supplied to the protective space and / or the oxygen concentration in the inert gas are provided for setting and / or maintaining a certain inertization level, the protective space 2 being provided by the inert gas system via one and the same supply pipe system 20 Inert gas is supplied.

Of course, it is also conceivable in accordance with the system Fig. 3 Furthermore, to provide a pressure storage container for the oxygen-enriched air and / or a pressure storage container for the nitrogen-enriched air, as in the embodiments according to Fig. 2 the case is.

With regard to the control of the nitrogen generator 11 via the control unit 12, it should finally be noted that the nitrogen generator 11 may comprise, for example, a cascade of single-membrane units, the number of individual-membrane units being selectable for separating oxygen from that supplied to the compressed-air source 10 via the control unit 12 Compressed air and for providing the nitrogen-enriched air at the first exit 11a of the nitrogen generator 11, the degree of nitrogen enrichment in the nitrogen-enriched air provided by the nitrogen generator 11 being controlled in response to the number of single-membrane units selected via the control unit 12 can.

It should be noted that the embodiment of the invention does not apply to the in the FIGS. 1 to 3 described embodiments is limited, but also in a variety of variants is possible.

LIST OF REFERENCE NUMBERS

1

inerting

2

shelter

10

Compressed air source; Ambient-air compressor

11

inert gas generator

11a

first output of the nitrogen generator for delivery of nitrogen-enriched air

11b

second output of the nitrogen generator for the delivery of oxygen-enriched air

12

control unit

20

first feed pipe system

21

controllable shut-off valve

22

Inert gas pressure storage tank

23

pressure-dependent valve device

24

controllable three-way valve

30

second feed pipe system

31

controllable shut-off valve

32

Oxygen pressure storage tank

33

pressure reducer

34

pressure-dependent valve device

40

Bypass pipe system

41

controllable shut-off valve

50

Oxygen detecting means

51

air nozzles

Claims (12)

1. An inerting device (1) for setting and maintaining a predefinable inerting level in a protected space (2) subject to monitoring, comprising:

   - a controllable inert gas unit (10, 11) for the providing of inert gas;

   - a first feed pipe system (20) connected to the inert gas unit (10, 11) which is connectable to the protected space (2) in order to feed the inert gas provided by the inert gas unit (10, 11) into said protected space (2); and

   - a control unit (12) designed to control the inert gas unit (10, 11) such that a specific predefinable inerting level is set and maintained in the protected space (2),

   wherein the inert gas unit (10, 11) comprises a nitrogen generator (11) connected to a compressed air source (10) to separate oxygen from the compressed air supplied by the compressed air source (10) and provide nitrogen-enriched air to a first outlet (11a) of the nitrogen generator (11), and wherein the nitrogen-enriched air provided by the nitrogen generator (11) can be fed as inert gas to the first feed pipe system (20) via a first outlet (11a) of said nitrogen generator (11),
   characterized in that
   the inerting device (1) further comprises a second feed pipe system (30) connected to the inert gas unit (10, 11) which can be connected to the protected space (2), wherein the oxygen separated from the compressed air by the nitrogen generator (11) can be fed as oxygen-enriched air to the second feed pipe system (30) via a second outlet (11b) of the nitrogen generator (11) in order to set and/or maintain a defined inerting level in the protected space (2).
2. The inerting device (1) according to claim 1, wherein
   the second feed pipe system (30) opens into the first feed pipe system (20) and is thus connectable to the protected space (2) by means of the first feed pipe system (20).
3. The inerting device (1) according to claim 1 or 2, further comprising a cut-off valve (31) disposed in the second feed pipe system (30) and controllable by the control unit (12) to break the connection between the second outlet (11b) of the nitrogen generator (11) and the protected space (2) establishable via the second feed pipe system (30).
4. The inerting device (1) according to any one of claims 1 to 3, wherein
   the inert gas unit (10, 11) further comprises a pressure storage tank (32) to store the oxygen-enriched air provided by the nitrogen generator (11), wherein the control unit (12) is designed to control a pressure reducer (33) disposed in the oxygen pressure storage tank (32) connectable to the second feed pipe system (30) so as to set the amount of inert gas supplied by the inert gas unit (10, 11) and to be fed to the protected space (2) and/or the oxygen concentration within the inert gas to the applicable value for setting and/or maintaining the defined inerting level.
5. The inerting device (1) according to claim 4, further comprising a pressure-controlled valve mechanism (34) which is open in a first predefinable range of pressure and allows the filling of the oxygen pressure storage tank (32) with the oxygen-enriched air provided by the nitrogen generator (11).
6. The inerting device (1) according to any one of the preceding claims, further comprising at least one cut-off valve (21) disposed in the first feed pipe system (20) and controllable by the control unit (12) to break the connection between the first outlet (11a) of the nitrogen generator (11) and the protected space (2) establishable via the first feed pipe system (20).
7. The inerting device (1) according to any one of the preceding claims, further comprising at least one oxygen detection mechanism (50) for detecting the oxygen content in the ambient air within the protected space (2), wherein the control unit (12) is designed to set the amount of inert gas supplied by the inert gas unit (10, 11) and to be fed to the protected space (2) and/or the oxygen concentration within the inert gas as a function of the oxygen content measured in the ambient air of the protected space (2).
8. The inerting device (1) according to claim 7, wherein the oxygen detection mechanism (50) is an aspirative oxygen detection mechanism.
9. The inerting device (1) according to any one of the preceding claims, wherein the inert gas unit (10, 11) further comprises a pressure storage tank (22) to store the nitrogen-enriched air preferably provided by the nitrogen generator (11), wherein the control unit (12) is designed to control a controllable pressure reducer (23) disposed in the nitrogen pressure storage tank (22) and connectable to the first feed pipe system (20) so as to set the amount of inert gas supplied by the inert gas unit (10, 11) and to be fed to the protected space (2) and/or the oxygen concentration within the inert gas to the applicable value for setting and/or maintaining the defined inerting level.
10. The inerting device (1) according to claim 9, further comprising a pressure-controlled valve mechanism (24) which is open in a first predefinable range of pressure and allows the filling of the nitrogen pressure storage tank (22) with the nitrogen-enriched air provided by the nitrogen generator (11).
11. The inerting device (1) according to any one of the preceding claims, wherein the predefinable inerting level is a full inertization level, a base inertization level or an accessibility level.
12. The inerting device (1) according to any one of the preceding claims, wherein the inert gas unit (10, 11) further comprises a bypass pipe system (40), preferably connectable through to the control unit (12) via a cut-off valve (41), which is connected on one side to a compressed air source (10) and on the other to the first feed pipe system (20) so as to feed the compressed air provided by the compressed air source (10) to the protected space (2) as fresh air when needed and thus set and/or maintain a defined inerting level in said protected space (2).

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