AU2019270433A1 - Fresh-air supply system for a submarine and submarine including such a system - Google Patents

Abstract

The invention relates to a fresh-air supply system (4) for a submarine, which includes: - a body (22) extending along a longitudinal axis (Z); - a pipe (20) for collecting fresh air, mounted so as to slide along the longitudinal axis inside the body between a retracted position and an extended position; - a valve (26) translatably mobile along the longitudinal axis (Z) between a closed position of an upper end (34) of the collection pipe and an open position of the collection pipe. One head (80) of the valve is placed outside the collection pipe. In the closed position, the head of the valve rests on a seat formed by an end lip (39) of the collection pipe which has a larger diameter than the inside diameter of the collection pipe.

Description

Fresh-air supply system for a submarine and submarine including such a system

The present invention relates to a fresh air supply system for a submarine. The invention also relates to a submarine comprising such a system. Diesel-electric powered submarines typically feature a retractable fresh air pipe to collect air from the surface of the water when the submarine is submerged at a shallow depth. The collected air is routed to the interior of the submarine, in particular to supply air to a diesel engine of the submarine. In practice, the architecture of the fresh air pipe is constrained by many factors, such as the need to resist the pressure exerted by the water while the submarine is submerged, whether the pipe is extended or not. A drawback resulting from these constraints is that, in the known systems, the open diameter for the passage of the fresh air is reduced, which generates pressure drops in the supply of fresh air which may be significant to the point of degrading the combustion performance of the engine. This may compromise the proper functioning of the submarine when submerged, which is not acceptable. The invention therefore aims to provide a fresh air supply system for a submarine which overcomes these drawbacks. To this end, the invention provides a fresh air supply system for a submarine, comprising: - a body extending along a longitudinal axis; - a fresh air collection pipe mounted to slide along the longitudinal axis inside the body between a retracted position and a extended position; - a valve translatably mobile along the longitudinal axis between a closed position of an upper end of the collection pipe and an open position of the collection pipe. A valve head is placed outside the collection pipe while, in the closed position, the valve head rests on a seat formed by an end lip of the collection pipe having a diameter greater than the inside diameter of the collection pipe. Thanks to the invention, the presence of the valve does not cause an excessive reduction in the air flow that may pass through the collection pipe, since the seat on which it rests is formed outside the pipe, and this seat has a diameter greater than the internal diameter of the pipe. Pressure losses are thus reduced.

According to advantageous but not mandatory aspects of the invention, such a fresh air supply system may incorporate one or more of the following characteristics, taken in isolation or in any technically feasible combination: - The system comprises a jack designed to move the collection pipe between the extended and retracted positions, the jack being placed outside the body. - The body comprises a lower tubular part and an upper tubular part aligned along the longitudinal axis and fixed to one another, the upper tubular part comprising at least one housing receiving a guide bearing to radially guide the collection pipe when sliding between the retracted and extended positions, the inner walls of the lower and upper tubular parts being maintained at a distance from the collection pipe to avoid contact with the collection pipe. - The collection pipe has flared walls at its upper end and which diverge towards the end lip. - The system further comprises a support structure integrally mounted with the upper end of the collection pipe, an actuator mounted on the support structure to open the valve, and a valve closing spring, the spring being placed in the interior of a hollow portion of the valve extending below the head of the valve and being received inside the collection pipe when the valve is in the closed position. - The jack comprises a rod translatably mobile along the longitudinal axis relative to a fixed casing of the jack that is integral with the body, the movable rod being connected to the upper end of the collection pipe by means of a connection part that is integral with the upper end of the collection pipe. - The system further comprises an auxiliary pipe mounted on the fixed casing of the jack and extending along the longitudinal axis. - The system comprises a first seal between the head of the valve and the end lip, and a second seal between a connecting part that is integral with the upper end of the collection pipe and a guide bearing mounted in the body. - The system has a volume of lubricant placed inside the body below the first and second seals and opposite the upper end of the collection pipe. According to another aspect, the invention relates to a submarine comprising such a fresh air supply system. The invention will be better understood and other advantages thereof will become more apparent in the light of the following description of an embodiment of a fresh air supply system for a given submarine by way of example and made with reference to the accompanying drawings, in which: - Figure 1 is a schematic longitudinal sectional view of a system for supplying fresh air to a submarine according to the invention; - Figure 2 is a schematic view of a lower part of a body of the supply system of Figure 1; - Figure 3 is a schematic view of an upper part of a body of the supply system of Figure 1; - Figure 4 is a schematic sectional view in perspective of a valve of the supply system of Figure 1; - Figure 5 is an enlarged view of zone V of Figure 1. Figure 1 shows a portion of a submarine 2 with diesel-electric propulsion comprising a fresh air supply system 4. Alternatively, the submarine 2 may be a nuclear powered submarine. The supply system 4 is designed to collect fresh air from the surface of the water when the submarine 2 is submerged and then to convey the collected air into the interior 6 of the submarine 2. For example , the collected fresh air is used to supply one or more diesel engines on board the submarine 2 and ensuring the propulsion of the submarine 2. For example, the supply system 4 is mounted on a casing 8 of the submarine 2, preferably being at least partially received inside the hull of the submarine 2. The interior 6 of the submarine 2 may include an air handling system to dehumidify the collected fresh air before its use. For example, the dotted lines bearing the reference 10 represent the top of the submarine hull. As illustrated in Figures 1 and 5, the supply system 4 comprises a pipe 20 for the collection of fresh air, a tubular body 22, a jack 24, a valve 26 of the pipe 20 mounted on an upper head of the supply system 4. The reference "Z" designates a fixed longitudinal axis of the supply system 4 that is oriented essentially vertically. In what follows, the term "radial" denotes a direction perpendicular to the longitudinal axis Z and passing through the longitudinal axis Z. When the terms "lower" and "upper" are used with reference to elements of the supply system 4, the term "lower" designates an element that is located closer to the casing 8 than a so-called "upper" element. The same applies to the terms "below" and "above", respectively.

In the example illustrated, the supply system 4 also comprises a fairing 30 and an auxiliary pipe 32, the respective roles of which are specified below. The pipe 20 is hollow and extends, along the longitudinal axis Z, between an upper end 34 and a lower end 36 which opens into the interior 6 of the submarine 2. Preferably, the pipe 20 has the shape of a cylinder with a longitudinal axis Z and with symmetry of revolution about the longitudinal axis Z. For example, the pipe 20 may be made of metallic material. By way of example provided by way of illustration and not necessarily limiting, the pipe 20 may have an internal diameter, measured radially with respect to the longitudinal axis Z, of between 10cm and 80cm. The walls of the pipe 20 have a thickness between 1cm and 2cm. The length of the pipe 20 lies between 2 meters and 10 meters. At its upper end 34, the pipe 20 has an end lip 39, for example in the form of a preferably flat flange. The lip 39 extends perpendicularly to the Z axis towards the outside of the pipe 20. In other words, the lip 39 extends outside the pipe 20. The diameter measured between the internal walls of the end lip 39 is greater than the internal diameter of the pipe 20. By way of illustration and not necessarily limiting, the internal diameter of the end lip 39, measured radially relative to the longitudinal axis Z, is greater than or equal to 110% or 120% of the internal diameter of the pipe 20. For example, the pipe 20 has, at its upper end 34, flared walls 38 which diverge from the center of the pipe 20 towards the end lip 39 and which are extended by the end lip 39. In other words, the internal diameter of the pipe 20 is essentially constant throughout its length except at the level of the flared walls 38 and the end tip 39, where the diameter is greater than the diameter measured along the remainder of the pipe 20. The pipe 20 is mounted inside body 22 and may slide relative to body 22, along the longitudinal axis Z, between a retracted position and an extended position relative to the body 22. For example, when the submarine 2 is submerged to a depth of 10 meters or 15 meters, the pipe 20 may be extended to bring its upper end 34 to the surface of the water in order to collect fresh air. It should be understood that when the submarine dives to a greater depth, the supply system 4 will be completely submerged and, therefore, it is no longer possible to collect air, since the pipe 20 is not long enough to be extended as far as the surface of the water. In Figures 1 and 5, the pipe 20 is shown in the retracted position. The pipe 20 is also called an "extendable pipe". The body 22 forms an outer protective casing for the pipe 20. Here, the body 22 is a tubular hollow body of essentially cylindrical shape aligned along the longitudinal axis Z and whose internal walls define an internal receiving volume to house the pipe 20. For example, the body 22 may be made of metallic material. According to examples, the length of the body 22 is less than or equal to the length of the pipe 20. In practice, the body 22 may be shorter than the pipe 20 if the flange 50 for fixing to the casing 8 is raised relative to the position of the lower end 36 when the pipe 20 is in the retracted position. For example, the length of the body 20 may be between 50% and 100% of the length of the pipe 20. Preferably, the body 22 comprises a lower tubular part 40 and an upper tubular part 42, aligned along the longitudinal axis Z and fixed to each other, for example by welding or by bolts or by rivets. In this example, the lower 40 and upper 42 tubular parts have a similar length, for example essentially equal to half the length of the body 22, wherein these lengths are measured along the longitudinal axis Z. The lower tubular part 40, illustrated in Figure 2, comprises a body 44 of cylindrical shape which extends between an upper end 46 and a lower end 48 on which is formed a lower flange 50 intended to be fixed on the casing 8. In this example, the body 44 also comprises a support 52 for fixing the jack 24. The upper tubular part 42, illustrated in Figure 3, comprises a body 54 of cylindrical shape which extends between an upper end 56 and a lower end 58. The lower end 58 of the upper tubular part 42 is connected to the 'upper end 46 of the lower tubular part 40. The upper tubular part 42 also comprises at least one housing 60, 62, in this example two in number, each having a guide bearing 64 (Figure 5) for radially guiding the pipe 20 during its sliding between the retracted and extended positions. To simplify the description, only the guide bearing 64 associated with the upper end of the pipe 20 is annotated in the figures. In the example illustrated, the housings 60 and 62 are formed by a local widening of the body 54 at the ends 56 and 58, respectively.

Preferably, the inner walls of the lower 40 and upper 42 tubular parts are maintained at a distance from the pipe 20 and do not contact the pipe 20. For example, the internal diameter of both the body 44 and the body 54 is distinctly greater than the external diameter of the pipe 20. In practice, however, the internal diameter of the bodies 44 and 54 is less than the diameter of the outside lip 39 of the pipe 20, the outer lip 39 not being intended to penetrate inside the body 22. It should therefore be understood that the contact between the body 22 and the pipe 20 is preferably only made at the level of the guide bearings 64, which are themselves installed only in the upper tubular part 42. According to embodiments, the upper tubular part 42 also comprises a fixing device 66 comprising a plate 68 for fixing the jack 24. In practice, during assembly of the supply system 4, the pipe 20 may be inserted into the body 22 through the upper end 56 without needing to access the lower tubular part 40, which simplifies handling operations. The jack 24 is designed to move the pipe 20 between the extended and retracted positions, for example in response to a control signal emitted from the interior 6 of the submarine 2. As illustrated in Figure 5, the jack 24 is placed outside the body 22, preferably by being fixed to the body 22, in this case by means of the mounting brackets 52 and 66. By placing the jack 24 outside the body 22, we avoid locally restricting the flow of fresh air inside the pipe 20, compared to known supply systems in which the jack is typically housed inside the fresh air collection pipe. Placing the jack 24 outside the body 22 therefore reduces the pressure drops in the pipe 20. According to embodiments, the jack 24 comprises a movable casing 70 and a rod 72, or piston, fixed along the longitudinal axis Z with respect to the movable casing 70. Reference 74 denotes an upper end of the mobile casing 70. The fixed rod 72 is integral with the body 22. The fixed rod 72 in this case is connected to the mounting support 52. The casing 70 is translatably mobile along the longitudinal axis Z relative to the fixed rod 72 and relative to the body 22. In the illustrated example, the casing 70 is connected to the connecting part 76 by the end 74. The connecting part 76 is connected directly to the end lip 39 of the pipe 20 and is higher than the upper end 56 of the body 22. For example, the casing 70 is mounted to slide in a through hole in the mounting plate 68.

The valve 26 is intended to close the pipe 20 in a hermetic manner to prevent the entry of water into the interior of the pipe 20 when the supply system 4 is completely submerged. More precisely, the valve 26 is translatably mobile along the longitudinal axis Z between a closed position, in which it hermetically closes the upper end 34 of the pipe 20, and an open position of the pipe 20, in which the upper end 34 is open to allow the passage of air. In Figure 5, the valve 26 is shown in the closed position. As illustrated in Figures 4 and 5, the valve 26 comprises a head 80, in this case with a rounded shape with a circular base centered on the longitudinal axis Z, for example in the shape of a mushroom or bell, and a central hollow cylindrical portion 82 which extends along the longitudinal axis Z and which delimits an interior volume 84. Preferably, the valve 26 has a shape having a symmetry of revolution about the longitudinal axis Z. The valve 26 in this case comprises a closing portion 86 which forms a lower bottom wall of the head 80. In the example illustrated, the head 80 further comprises a circular groove 88, or housing, which opens onto a lower face of the head 80 and extends between an outer radial edge of the closure portion 86 and the outer periphery of the head 80. In an assembled configuration of the supply system 4, the head 80 of the valve 26 is placed outside the pipe 20. In other words, the head 80 of the valve 26 is outside the pipe 20 in both its open position and its closed position. In addition, in the closed position, the head 80 of the valve 26 rests on a seat formed by the end tip 39 of the pipe 20. For example, in the closed position, the outer periphery of the lower base of the head 80 rests directly on the end tip 39. Thanks to the arrangement of the valve 26, the lateral air suction section of the pipe 20 is increased at the upper end 34 when compared with known systems in which the valve is housed integrally inside the fresh air pipe. The pressure drops in the pipe 20 are thus reduced. The supply system 4 also comprises a support structure 90 including in this case an upper part 92 and a base 94, as well as an actuator 96 mounted on the support structure 90. The support structure 90 is mounted integrally with the upper end 34 of the pipe 20. For example, the base 94 is fixed to the upper lip 39.

The actuator 96 is designed to open the valve 26, for example in response to a control signal transmitted from inside the submarine. The actuator 96 in this case is a hydraulic or pneumatic piston jack, fed by a supply duct 98, which is connected to the valve 26 so as to move it to its open position. In the illustrated example, the central portion 82 slides around a piston 100 of the actuator 96 which is fixed. The actuator 96, when activated, lifts the valve 26 and moves it away from its seat formed by the end tip 39. The supply system 4 also comprises a spring 102 arranged to ensure the closing of the valve 26 when the actuator 96 is not activated. For example, the spring 102 may be a compression coil spring exerting a return force along the longitudinal axis Z so as to return the valve 26 to the closed position. Preferably, the spring 102 is placed in the hollow volume 84 inside the central portion 82 of the valve and thus extends under the head 80 of the valve 26. When the valve 26 is in the closed position, the spring 102 is thus housed inside the pipe 20. This arrangement makes it possible to avoid the spring 102 from coming into contact with water when the valve 26 is closed and the supply system 4 is submerged, which makes it possible to limit the risk of corrosion and therefore improve the life and reliability of spring 102. Advantageously, the tightness of the closure of the pipe 20 by the valve 26 is provided by a first sealing device 110 and a second sealing device 112. The first sealing device 110 has at least one seal and is placed between the head 80 of the valve 26 and the end tip 39, for example, being housed inside the groove 88. Preferably, the sealing device 110 comprises two seals based on different technologies, so as to ensure redundancy and improve the sealing. For example, an O-ring seal may be placed at the bottom of the groove 88 and a flat seal placed in the groove 88 in contact with the O-ring so as to close the groove 88. The second sealing device 112 comprises a seal placed between the connecting part 26 integral with the upper end 34 of the pipe 20 and the guide bearing 64 associated with the upper end of the pipe 20, namely, in this case, the guide bearing 64 housed in the housing 60. It should therefore be understood that the sealing devices 110 and 112 are arranged below the head 80 of the valve 26 and above the guide bearing 64.

The supply system 4 is thus designed to withstand the pressure exerted by the water when the submarine 2 is submerged to its maximum immersion depth. In other words, when the supply system 4 is completely submerged, water cannot enter the interior of the pipe 20, provided that the valve 26 is closed before submersion. This resistance is partly due to the fact that the pipe 20 is mounted inside the body 22, which improves the mechanical strength and the tightness of the supply system. According to embodiments, at least one additional seal 114 is installed on the guide bearing 64 associated with the upper end of the pipe 20. In the illustrated example, the additional seals 114 are two in number and are arranged one above the other. For example, the seals 112 and 114 may be circular O-rings centered on the longitudinal axis Z. Preferably, the seals 112 and 114 are made of an elastomeric material. In addition, the guide bearing 64 in this case comprises a scraper 116, for example produced in the form of a ring-shaped blade, capable of coming into direct contact with the periphery of the outer walls of the pipe 20. The scraper 116 in this case is arranged above the at least one additional seal 114. Advantageously, the supply system 4 comprises a volume of lubricant 118, for example grease, in order to lubricate the outer walls of the pipe 20 during each movement between the retracted and extended positions. The lubricant is placed inside the body 22, between the two bearings 64, preferably on at least part of the faces of the guide bearing 64 which are in contact with the outer walls of the pipe 20. The volume of lubricant 118 is here confined in a zone delimited on either side by the respective seals of the two guide bearings 64. Advantageously, the upper part 42 of the body 22 comprises a supply orifice 119 allowing the volume of lubricant 118 to be recharged. Particularly advantageously, when the pipe 20 is moved to the retracted position, the scraper 116 scrapes the outer walls of the pipe 20, which cleans them and frees them from the dirt resulting from exposure to seawater. In this way, the amount of dirt that can penetrate inside the body 22 is limited. In addition, it improves the effect of lubrication, since the surface of the pipe 20 is cleaned before applying the lubricant. According to examples, the fairing 30 comprises an outer casing, for example of metallic material or of composite material, which at least partially surrounds the head of the supply system 4 when the pipe 20 is in the retracted position. For example, the fairing 30 may be integral with the pipe 20, in this case by being mounted on the connecting part 76. Preferably, the fairing 30 has a stealth shape, i.e. a shape allowing the reflection of radar signals to be reduced. Alternatively, the fairing 30 may have a shape which makes it possible to reduce the hydrodynamic resistance when the submarine 2 moves through the water. According to embodiments, the auxiliary pipe 32, provides a passage between the interior 6 and the exterior of the submarine 2 for cables and/or conduits, in particular the power supply conduit 98. In the example illustrated, the auxiliary pipe 32 is mounted on the fixed casing 70 of the jack 24 and extends along the longitudinal axis Z. The auxiliary pipe 32 may be a telescopic pipe. The auxiliary pipe 32, by being connected to the body 22, strengthens the mechanical strength of the body 22 during immersion by increasing the transverse stiffness of the body 22. Alternatively, the supply system 4 may be used independently of the auxiliary pipe 32. The embodiments and the variants considered above may be combined with one another to generate new embodiments.

Claims (10)

1. Fresh air supply system (4) for a submarine (2), comprising: - a body (22) extending along a longitudinal axis (Z); - a fresh air collection pipe (20), mounted to slide along the longitudinal axis (Z) inside the body (22) between a retracted position and a extended position; - a valve (26) translatably mobile along the longitudinal axis (Z) between a closed position of an upper end (34) of the collection pipe and an open position of the collection pipe; characterized in that a head (80) of the valve (26) is placed outside the collection pipe (20) and in that in the closed position,, the head (80) of the valve (26) rests on a seat formed by an end lip (39) of the collection pipe (20) having a diameter greater than the internal diameter of the collection pipe (20).

2. Supply system (4) according to claim 1, characterized in that it comprises a jack (24) designed to move the collection pipe (20) between the extended and retracted positions, the jack (24) being placed outside the body (22).

3. Supply system (4) according to claim 1 or claim 2, characterized in that the body (22) comprises a lower tubular part (40) and an upper tubular part (42) aligned along the longitudinal axis (Z) and fixed to one another, the upper tubular part comprising at least one housing (60, 62) housing a guide bearing (64) for radially guiding the collection pipe (20) as it slides between the retracted and extended positions, the inner walls of the lower and upper tubular portions (40, 42) being kept at a distance from the collection pipe (20) and without contact with the collection pipe.

4. Supply system (4) according to any one of the preceding claims, characterized in that the collection pipe (20) has, at its upper end (34), flared walls (38) which diverge towards the end tip (39).

5. Supply system (4) according to any one of the preceding claims, characterized in that it further comprises: - a support structure (90) integral with the upper end (34) of the collection pipe (20), - an actuator (96) mounted on the support structure (90) to open the valve, and

- a spring (102) for closing the valve, and in that the spring (102) is placed within a hollow portion (82) of the valve (26) extending below the head (80) of the valve (26), the spring (102) being housed inside the collection pipe (20) when the valve (26) is in the closed position.

6. Supply system (4) according to any one of claims 2 to 5, characterized in that the jack (24) comprises a casing (70) translatably mobile along the longitudinal axis (Z) relative to a fixed rod (72) of the jack (24) integral with the body (22), the movable casing (70) being connected to the upper end (34) of the collection pipe (20) by means of a connecting part (76) integral with the upper end (34) of the collection pipe (20).

7. Supply system (4) according to claim 6, characterized in that it further comprises an auxiliary pipe (32) mounted on the movable casing (70) of the jack (24) and extending along the longitudinal axis (Z).

8. Supply system (4) according to any one of the preceding claims, characterized in that it comprises a first sealing device (110) between the head (80) of the valve (26) and the end lip (39), and a second sealing device (112) between a connecting part (76) integral with the upper end (34) of the collection pipe (20) and a guide bearing (64) mounted in the body (22).

9. Supply system (4) according to claim 8, characterized in that it comprises a volume of lubricant (118) placed inside the body (22) below the first and second sealing devices (110, 112) and opposite the collection pipe (20).

10. Submarine (2) characterized in that it comprises a fresh air supply system (4) according to any one of the preceding claims.