EP2707280B1 - Underwater vehicle internal assembly fitted with a system for treating ambient gas and associated treatment method - Google Patents

Description

The present invention relates to an inner assembly of underwater vehicle, according to the preamble of claim 1.

Such an inner assembly is intended to equip including a military submarine carrying a crew. In particular, the inner assembly is intended to be disposed in a conventional submarine devoid of nuclear propulsion.

Conventional submarines are usually propelled by an internal combustion engine such as a diesel.

To allow immersion of the submarine for a substantial period of time, it is necessary to provide a treatment system for renewing the oxygen present on board the interior volume delimited by the thick hull of the submarine.

In conventional submarines, it is known to ventilate the interior volume of the submarine during the submarine engine snorkel charge.

This operation is very indiscreet, since it requires starting the engine in the vicinity of the surface for a significant time, of the order of 10 minutes.

However, this method is commonly used on conventional submarines, since submarine batteries must be recharged periodically.

Alternatively, for longer dives submarine, it is known to ship oxygen candles to provide additional oxygen when it is not possible to go to the surface to perform a renewal of air . These candles are pyrotechnically primed and release oxygen. However, the release of oxygen is limited in relation to the volume and mass of each candle. Such candles are also expensive and may present risks of use, especially diving.

In conventional submarines equipped with an independent propulsion of air (or AIP), it is known to periodically collect a portion of the stored oxygen for the purposes of AIP propulsion. However, these samples reduce the autonomy of the propulsion immersion.

In nuclear-powered submarines, it is known to use an oxygen production plant that operates for example by electrolysis of seawater to extract oxygen. Such a plant, however, is a heavy consumer of electrical energy, and therefore can not be implemented in a conventional submarine.

Submarines are also known comprising oxygen storage in liquid or gaseous form, in particular to ensure an independent propulsion of air (AIP). Such storage is difficult to implement in a submarine, and require many precautions, given the confined space of the submarine. In addition, the handling facilities of these storage are complex and expensive, and are very cumbersome.

US 3,740,928 describes an apparatus for absorbing carbon dioxide in the air.

A publication entitled "Submarine Air Purification and Monitoring" (Ranieri et al.), Dated 22/10/2003, describes a method for the purification and treatment of air in submarines. The document US3164454 is considered to be the closest state of the art and discloses the preamble of claim 1.

An object of the invention is therefore to obtain an interior assembly of underwater vehicle that provides a periodic renewal of the atmosphere present in the interior volume of the submarine, while having a low energy consumption and an absence of consumables.

For this purpose, the subject of the invention is an assembly according to claim 1.

The assembly according to the invention may comprise one or more of the features of claims 2 to 8, taken separately or in any technically possible combination.

The invention also relates to an underwater vehicle according to claim 9.

The invention also relates to a method for conditioning the ambient gas present in the interior volume according to claim 10.

The method according to the invention may comprise one or more of the features of claims 11 and 12, taken alone or in any technically possible combination.

• la figure 1 est une vue schématique en coupe suivant un plan vertical médian d'un premier engin sous-marin selon l'intention
• la figure 2 est une vue schématique de l'ensemble intérieur selon l'invention de l'engin de la figure 1 ;
• la figure 3 est un diagramme synoptique fonctionnel d'un générateur d'azote présent dans l'ensemble de la figure 2, dans une première configuration de fonctionnement;
• la figure 4 est une vue analogue à la figure 3 dans une deuxième configuration de fonctionnement.

The invention will be better understood on reading the description which follows, given solely by way of example, and with reference to the appended drawings, in which:

• the figure 1 is a schematic sectional view along a median vertical plane of a first underwater craft according to the intention
• the figure 2 is a schematic view of the inner assembly according to the invention of the machine of the figure 1 ;
• the figure 3 is a functional synoptic diagram of a nitrogen generator present in the whole of the figure 2 in a first operating configuration;
• the figure 4 is a view similar to the figure 3 in a second operating configuration.

In all that follows the pressures are expressed in absolute bars, unless the opposite is specified.

A first underwater vehicle 10 according to the invention is illustrated by the figure 1 . This machine 10 is advantageously a conventional submarine devoid of nuclear propulsion means.

The underwater vehicle 10 comprises in known manner an inner thick shell 12, and an outer shell 14 delimiting with the thick shell 12 at least one ballast 16.

The underwater vehicle 10 comprises a solid mass 18 projecting above the outer shell 14, a propulsion assembly 20 and an inner assembly 22 defining an interior gas volume 24 intended to receive a crew.

The propulsion assembly 20 comprises in particular an internal combustion engine 25 such as a diesel engine. Conventionally, the propulsion assembly 20 further comprises a schnorchel tube 26 extending through the solid mass 18, then to the engine 25 for supplying the engine 25 with external gas, when the vehicle 10 is navigating further comprises a schnorchel tube 26 extending through the solid mass 18, then to the engine 25 to supply the engine 25 with external gas, when the machine 10 is sailed underwater. The propulsion assembly 20 further comprises an alternator for recharging batteries 28.

The inner assembly 22 comprises an enclosure 40 substantially sealing the inner volume 24, the chamber 40 containing an ambient gas. The inner assembly 22 further comprises a system 42 for treating the ambient gas present in the chamber 40. As will be seen below, the treatment system 42 is able to capture a portion of the nitrogen present in the ambient gas to place the interior volume 24 in slight depression, then relargérère nitrogen captured outside the underwater vehicle 10, during a purge step.

The inner assembly 22 further comprises a pipe for supplying an oxygen-rich external gas for balancing the pressure in the interior volume 24. The external gas is, for example, the ambient air present around the sub-unit. 10 when the craft 10 floats on the surface of the water. The supply pipe is advantageously formed by the schnorchel tube 26 or is connected to this tube 26.

The enclosure 40 is for example delimited by the thick shell 12 or by a wall disposed in the thick shell 12.

The treatment system 42 comprises an assembly 50 for sampling and conveying ambient gas, a treatment device 51 comprising a nitrogen generator 52 and a set 54 for purging the recovered nitrogen.

The treatment system 42 also advantageously comprises a conduit 56 for recycling ambient gas treated in the enclosure 40.

As illustrated by figure 2 , the sampling and conveying assembly 50 comprises a sampling line 60 and an upstream compressor 62. It optionally comprises an upstream filter 64 and an upstream storage 66 of compressed ambient gas.

The upstream pipe 60 opens upstream in the interior volume 24 via an upstream inlet 68. It connects the upstream inlet 68 to the compressor 62.

The compressor 62 is capable of compressing the ambient gas taken from the internal volume 24 substantially at atmospheric pressure to a pressure greater than 5 bar and in particular between 7 bar and 10 bar.

The compressor 62 produces a compressed ambient gas output. The filter 64 is able to purify the compressed ambient gas, in particular to remove impurities and possibly part of the water contained therein. The upstream storage 66 is for example formed by a balloon capable of containing the ambient gas under pressure when the treatment device 51 is not functional.

According to the invention, the treatment device 51 comprises a nitrogen generator 52, to produce a treated stream rich in nitrogen and a discharge stream rich in oxygen.

By "rich in nitrogen" is meant that the treated stream has a nitrogen content greater than that of the ambient gas introduced into the generator, and for example greater than 99 mol%.

"Oxygen-rich" means that the discharge stream has an oxygen content greater than that of the ambient gas introduced into the generator 52. The oxygen content in the oxygen-rich discharge stream is, for example, greater than 28%. molar.

The nitrogen generator 52 is for example of the adsorption type under pressure and in particular pressure swing adsorption, designated by the English term "pressure swing adsorption".

It comprises at least one adsorber 70A, 70B capable of operating in an adsorption configuration at an adsorption pressure, in which the adsorber selectively adsorbs a gas contained in a gaseous mixture and a desorption configuration, at a lower pressure, wherein the adsorbed gas is released.

As illustrated by Figure 3 or figure 4 the generator 52 comprises a first adsorber 70A and a second adsorber 70B connected in parallel with the first adsorber 70A. further comprises a valve distributor 72 and a control unit 74 for controlling the distributor 72 between a first adsorption configuration in the first adsorber 70A and a second adsorption configuration in the second adsorber 70B which will be described in more detail. low.

The nitrogen generator 52 is for example a generator marketed by the company INNOVATIVE GAS SYSTEMS under the trademark NITROSWING ®.

Each adsorber 70A, 70B comprises a tank 76A, 76B containing an adsorbent material 77.

In a first embodiment, the adsorbent material 77 is able to selectively capture the oxygen present in an ambient gas containing in particular nitrogen and oxygen, without significantly capturing the nitrogen, at a high pressure P1 greater than the atmospheric pressure, and in particular equal to the pressure of the compressed ambient gas received from the conveyor assembly 50.

The adsorbent material 77 is also suitable for releasing the oxygen captured at a low pressure P2 lower than the high pressure P1, for example substantially equal to the atmospheric pressure.

In this example, the adsorbent material is formed by a divided material such as a carbon-containing molecular sieve. The divided material is for example a porous material. More generally, the adsorbent material is selected from active carbons, silica gels, alumina or zeolites.

The adsorption surface defined by the material 77 is for example greater than several square meters, in particular of the order of several hundred square meters. The affinity of the adsorbent material. The adsorbed gas is, for example, of a chemical or physical nature, in particular depending on the size of the pores contained in the adsorbent material.

In a variant, the adsorbent material 77 is able to preferentially capture the nitrogen present in the gaseous mixture, without significantly capturing the oxygen present at the high pressure P1. The adsorbent material 77 is capable of releasing the nitrogen captured at the low pressure P2 lower than the high pressure P1.

The valve distributor 72 comprises an inlet pipe 78 connected to the outlet of the conveyor assembly 50, a first upstream pipe 80A and a second upstream pipe 80B. The lines 80A and 80B connect the inlet pipe 78 respectively to the first adsorber 70A and the second adsorber 70B. Each upstream line 80A, 80B is provided with an upstream valve 82A, 82B.

The downstream distributor 72 further includes a first downstream conduit 84A, and a second downstream conduit 84B that converge in a nitrogen-rich stream evacuation conduit 86.

The downstream pipes 84A and 84B are respectively provided with a first downstream valve 88A and a second downstream valve 88B.

The distributor 72 further comprises a first recirculation tapping 90A and a second recirculation tapping 90B converging in the recycle line 56 to remove the oxygen-rich stream.

The first tapping 90A is stitched on the first upstream pipe 80A, advantageously downstream of the upstream valve 80A. It is provided with a first recycling valve 92A.

The second stitch 90B is stitched on the second upstream pipe 80B, advantageously downstream of the upstream valve 82B. It is equipped with a second recycling valve 92B.

As will be described in detail below, the control unit 74 is able to control the various valves 82A, 82B; 84A, 84B; 92A, 92B between a first adsorption configuration in the first adsorber 70A and desorption in the second adsorber 70B, and a second adsorption configuration in the second adsorber 70B and desorption in the first adsorber 70A.

With reference to the Figure 2 , the purge assembly 54 includes a downstream compressor 100 for compressing the nitrogen-rich stream formed in the generator 52, a purge conduit 102 connected to another outlet of the downstream compressor 100, and a temporary storage assembly 104. 'nitrogen.

Optionally, the purge assembly 54 comprises a downstream buffer tank 106 placed upstream of the downstream compressor 100.

The downstream compressor 100 is connected upstream to the generator 52, in particular to the exhaust pipe 86 of the nitrogen-rich stream.

It is capable of compressing the nitrogen-rich stream flowing in the pipe 86 to a high pressure, greater than the pressure prevailing in the generator 52.

The pressure at the outlet of the downstream compressor 100 is greater than the immersion pressure, and may in particular be greater than 200 bar, and in particular of the order of 250 bar.

The compressor 100 comprises an outlet pipe 107 provided with a non-return valve 108.

The purge duct 102 is stitched on the outlet duct 107, downstream of the non-return valve 108.

It comprises a normally closed purge valve 110 and a non-return device 112. In the example shown in solid lines on the Figure 2 , the purge duct 102 is intended to open out of the underwater vehicle, whether underwater or above the surface.

The storage assembly 104 comprises at least one tank 114 of pressurized nitrogen connected to the outlet line 107 of the downstream compressor 100. Each tank 114 has a volume greater than that of the buffer tank 106 when it is present. This volume may be of the order of several hundred liters, for example of the order of 400 liters.

A process for treating the ambient gas present in the interior volume 24 of the interior assembly 22 will now be described.

Initially, in a first phase, the underwater vehicle 10 is underwater. During this phase, the interior volume 24 is occupied by the crew.

The amount of oxygen present in this interior volume 24 therefore decreases progressively.

During this phase, the processing system 42 is activated. For this purpose, the compressor 62 is started to take a given quantity of ambient gas present in the internal volume 24 through the upstream inlet 68 and the withdrawal pipe 60.

This sampling is carried out either continuously or at regular intervals.

The pressure in the interior volume 24 therefore decreases gradually as sampling takes place.

The ambient gas taken by the upstream compressor 62 is then compressed to a pressure greater than 5 bar, and in particular of the order of 10 bar.

The compressed ambient gas is then introduced into the nitrogen generator 52 through the inlet pipe 78.

In a first operating configuration of the generator 52, the first adsorber 70A operates as an adsorber, while the second adsorber 70B desorbs and regenerates.

In this configuration, the control unit 74 opens the upstream valve 82A, 82B to allow the passage of the compressed ambient gas to the first adsorber 70A and prohibit the passage of fluid from the inlet duct 78 to the second adsorber 70B.

The compressed ambient gas thus enters the tank 76A of the first adsorber 70A. The oxygen present in the ambient gas is adsorbed at least in part in the adsorbent material 77, forming a nitrogen-rich stream.

The control unit 74 holds the outlet valve 88A open. The nitrogen-rich stream flows into the first upstream pipe 80A and then into the evacuation pipe 86.

A portion of the nitrogen-rich stream is withdrawn from line 80A and then enters vessel 76B of second adsorber 70B after expansion in downstream valve 88B.

The first recycling valve 92A is closed by the control unit 74. The second recycling valve 92B is opened by the control unit 74.

The oxygen present on the adsorbent material 77 of the second adsorber 70B. desorbs and forms the oxygen-rich stream. This current passes successively through the second downstream valve 92B, the second piping line 90B and the recycling line 56. The oxygen-rich stream thus formed is then reintroduced into the internal volume 24.

When the adsorbent material present in the first tank 76A is saturated, the control unit 74 switches the distributor 72 into its second configuration to direct the pressurized ambient gas stream to the second adsorber 70B.

The unit 74 thus opens the second front valve 82B and closes the first upstream valve 82A. As illustrated by figure 4 the compressed ambient gas then passes into the adsorbent material 77 of the second tank 76B and the oxygen present in this gas is adsorbed. The nitrogen-rich stream formed at the outlet of the second adsorber 70B is then conveyed through the second downstream pipe 84B and then through the discharge pipe.

Part of this stream is withdrawn to regenerate the first adsorber 70A, through the first downstream pipe 86A and the downstream valve 88A. The oxygen present in the adsorbent material 77 of the first vessel 76A forms an oxygen-rich stream which flows successively through the first tapping 90A and the first valve 92A held open by the control unit 74.

In the first configuration, as in the second configuration, a nitrogen-rich stream is thus formed in the generator 52 to be evacuated through the discharge line 86. Likewise, an oxygen-rich discharge stream is formed simultaneously in the generator 52 to be discharged into the recycling line 56 and reintroduced into the interior volume 24.

The generator 52 then switches periodically between the first configuration and the second configuration.

Then, the nitrogen-rich stream present in the discharge line 86 passes into the downstream compressor 100 to be compressed at a pressure higher than the immersion pressure.

Depending on the choice of the flight crew, the evacuation valve 110 is either open or closed. When it is opened, the nitrogen-rich stream is ejected outside the underwater vehicle because of its pressure greater than the immersion pressure. When the valve 110 is closed, closing the exhaust pipe 102, the nitrogen-rich stream is then directed to the storage 114 to be stored at high pressure, for subsequent purging.

When the pressure in the internal volume 24 decreases beyond a given value, for example greater than or equal to 100 mbar, or at given time intervals, for example of the order of 24 hours, the underwater vehicle 10 goes up to the vicinity of the surface to place at least the schnorchel tube 26 in a gaseous volume above the surface of the water.

The pressure in the internal volume 24 is raised to atmospheric pressure via the external gas supply conduit, here formed by the schnorchel tube 26.

Oxygen-rich external gas is thus injected into the interior volume 24, which makes it possible to enrich the ambient gas with oxygen.

This balancing is done very quickly, for example over a period of less than 10 seconds, in particular of the order of a few seconds, to maintain the discretion of the underwater vehicle. Nitrogen purge can be advantageously carried out during equilibration.

In a variant, represented in dotted lines on the figure 2 , the purge assembly 54 includes a purge line 102A for connection to a submerged purge outlet 122. In this case, the submerged outlet 122 may be provided with a continuous purge device in a body of water.

In this variant, the pressure supplied by the downstream compressor 100 can be reduced to be substantially equal to the pressure of the generator 52 plus a few tens of bars.

By varying, the submerged outlet 122 is configured to allow rapid purge in the body of water.

In a variant, at least a portion of the nitrogen collected at the outlet of the generator 52 or the downstream compressor 100 is redirected to a local present in the volume 24, with a view to inerting this room or to a utility consuming water. nitrogen.

Thanks to the invention that has just been described, it is possible to have a system 42 for treating ambient gas in the interior volume 24 of an underwater vehicle 10 which can be regenerated to infinity, allowing an autonomy of the underwater vehicle 10 vis-à-vis consumables such as candles or oxygen storage.

The treatment system 42 has a very low power consumption compared to an oxygen plant present for example on a nuclear-powered underwater vehicle. Thus, the power can be limited to a few kilowatts, against several tens of kilowatts when an oxygen plant is present.

In addition, the inner assembly 22 according to the invention is used very safely, since no pyrotechnic risk related to candles, oxygen storage, or the presence of hydrogen is present.

The treatment system 42 is purged very rapidly, limiting at least the indiscretion of the underwater vehicle 10. In particular, this system 42 is much more discreet than a ventilation system when charging at the using schnorchel tube 26.

In addition, the renewal of air can be performed during routine operations of raising to the surface of the underwater vehicle 10, for example during radio breaks.

Alternatively, the nitrogen generator is a membrane nitrogen generator. The partial pressures on either side of the membrane are different to allow the selective transfer of a portion of the gas contained in the gas flow injected into the generator through the membrane. Such a generator thus generates a treated stream rich in nitrogen and a discharge stream rich in oxygen.

Claims (12)

1. An inner assembly (22) of a submarine craft (10), of the type comprising:

   - an enclosure (40) delimiting an inner volume (24) containing an ambient gas;

   - a system (42) for treating ambient gas, the treatment system (42) comprising:

   ∘ an upstream intake (68) for withdrawing ambient gas from the enclosure (40) ;

   ∘ a device (51) for treating ambient gas;

   ∘ an assembly (50) for conveying ambient gas from the upstream intake (68) towards the treatment device (51) ;

   the treatment device (51) comprising at least one nitrogen generator (52) capable of generating a nitrogen-rich treated stream and an oxygen-rich discharge stream from the drawn-off ambient gas, the treatment system (42) comprising a purge assembly (54) connected to the nitrogen generator (52) to evacuate the nitrogen-rich stream towards the outside of the submarine craft (10),
   the nitrogen generator (52) comprising a first adsorber (70A), and a second adsorber (70B) mounted in parallel with the first adsorber (70A), the nitrogen generator (52) comprising a control unit (74) capable of selectively pressurising the first adsorber (70A) and the second adsorber (70B), so that in a first configuration the first adsorber (70A) produces a nitrogen-rich treated stream and the second adsorber (70B) produces an oxygen-rich discharge stream,
   characterized in that, in a second configuration, the first adsorber (70A) produces the oxygen-rich discharge stream and the second adsorber (70B) produces the nitrogen-rich treated stream.
2. The inner assembly (22) according to claim 1, characterized in that the conveying assembly (50) comprises an upstream compressor (62).
3. An inner assembly (22) according to claim 1 or claim 2, characterized in that the first adsorber (70A) and the second adsorber (70B) comprise an adsorption material (77) capable of selectively adsorbing oxygen at a first high pressure, the adsorption material (77) being able to release the adsorbed oxygen at a second low pressure lower than the first high pressure.
4. The inner assembly (22) according to claim 1 or claim 2, characterized in that the first adsorber (70A) and the second adsorber (70B) contain an adsorption material capable of selectively adsorbing nitrogen at a first high pressure, the adsorption material being capable of releasing the nitrogen at a second low pressure lower than the first high pressure.
5. The inner assembly (22) according to any of the preceding claims, characterized in that the purge assembly (54) comprises a downstream compressor (100) connected to the nitrogen generator (52) to compress the nitrogen-rich treated stream, the purge assembly (54) comprising storage means (114) to store the compressed treated stream.
6. The inner assembly (22) according to any of the preceding claims, characterized in that the purge assembly (54) comprises a purge duct (102) intended to lead to outside the submarine craft (10), the purge duct (102) being equipped at least with one purge valve (110).
7. The inner assembly (22) according to claim 6, characterized in that the purge duct (102) is arranged at least in part above the enclosure (40) to lead into a gaseous volume located above the enclosure (40) when the submarine craft (10) is at least partly submerged.
8. The inner assembly (22) according to claim 6, characterized in that the purge duct (102) leads to opposite the enclosure (40) or underneath the enclosure (40) to open into a volume of water.
9. A submarine craft (10), characterized in that it comprises an inner assembly (22) according to any of the preceding claims.
10. A process for treating ambient gas present in the inner volume (24) of an inner assembly (22) according to any of the preceding claims, of the type comprising the following steps:

    - the progressive evacuation of ambient gas to outside the inner volume (24), the evacuation step comprising the drawing-off of ambient gas via the upstream intake (68), the conveying of the ambient gas stream as far as the nitrogen generator (52) via the conveying assembly (50), the formation of a nitrogen-rich treated stream, and the formation of an oxygen-rich discharge stream in the nitrogen generator (52), the pressure in the inner volume (24) decreasing gradually;

    - equilibrating the pressure inside the inner volume by injecting an outside oxygen-rich stream into the inner volume (24),

    the process being characterized in that the nitrogen generator (52) comprises a first adsorber (70A) and a second adsorber (70B) mounted in parallel with the first adsorber (70A), the nitrogen generator (52) comprising a control unit (74) capable of selectively pressurising the first adsorber (70A) and the second adsorber (70B), the evacuation step comprising a first phase to produce a nitrogen-rich treated stream by the first adsorber (70A) and an oxygen-rich discharge stream by the second adsorber (70B), then a second phase to produce a nitrogen-rich treated stream by the second adsorber (70B) and an oxygen-rich discharge stream by the first adsorber (70A).
11. The process according to claim 10, characterized in that it comprises a step to purge the nitrogen-rich stream generated by the treatment generator (52), the purge step being performed during the equilibrating step, the nitrogen-rich stream generated by the nitrogen generator (52) advantageously being stored in storage means (114) of the purge assembly (54) during the evacuation step.
12. The process according to claim 10, characterized in that it comprises a step to purge the nitrogen-rich stream produced by the nitrogen generating assembly (52), the purge step being conducted in an expanse of water when the submarine craft is submerged.

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