FR2930817A1 - SYSTEM FOR CLOSING A GAS EXHAUST DUCT FROM A MISSILES LAUNCHER - Google Patents

Abstract

This shutter system (14) for the chimney of a missile launcher, the launcher (1) comprising at least one container (2, 3), able to receive at least one missile (4, 5), and a pipe ( 10) for evacuation of the propulsion gases comprising a chimney (11) for extracting the gases, the container being in communication with the pipe during firing of the missile and the pipe being in communication with the atmosphere (12) via the chimney equipped with said closure system, is characterized in that the closure system comprises at least one panel (12, 13) and a panel retaining means (18, 19) movable between a closed position and a position of opening, the retaining means comprising a return means (18a) of the open position to the closed position and a power dissipation means (18b) resulting from the opening movement and the closing movement.

Description

The invention relates to the field of missile launchers. More particularly, the invention relates to a shutter system of the evacuation gas conduit propulsion equipment launcher.

In general, as shown in FIG. 1 in the appendix, a missile launcher, for example a launcher disposed vertically in the hull of a carrier ship, comprises two parallel rows of containers located above a common duct. exhaust gas. The rows of containers are separated from each other by a central stack arranged vertically. At its lower end, the exhaust stack is in communication with the exhaust duct and, at its upper end, it is in communication with the atmosphere through a mouth equipped with a flue. door closing the chimney and can be opened. This door is necessary to ensure the integrity of the launcher in a marine environment of use.

During the deliberate fire of a missile contained in one of the containers, the propellant gases are evacuated through the bottom of the container which is placed in communication with the gas evacuation pipe by the opening of a lid located on the bottom of the container. A flow is then created, as indicated by the arrow in FIG. 1, from the inside of the container to the evacuation duct, then to the atmosphere via the chimney whose door is open. According to the prior art, the chimney door is actuated in opening when firing a missile. More specifically, a first control signal is transmitted towards an actuating system for moving the door in opening. Once the missile has been fired and the propellant gases have been exhausted from the interior of the launcher, a second control signal is sent to the actuation system for movement of the closing door. In this known mode of operation, the opening time of the door is taken into account, opening it sufficiently early before the firing of the missile to be fully open at this time.

The overpressure in the extraction chimney is caused either by the propulsion gases of a deliberately fired missile or by untimely emission of gas. To take account of such events, a chimney door according to the prior art is provided with a panel serving as a fuse holder. This panel is ejected in the case of too high overpressure prevailing in the chimney. Following an untimely emission and the ejection of the panel, it is necessary to intervene on the launcher to replace this panel.

In addition, the dimensioning of the panel fuse holder is complex. It is done following a series of calibrations by estimating the parameters of a characteristic untimely emission. In particular, this panel must be adapted to the flow parameters (flow, pressure, etc.) of such untimely emission. Finally, such panels have the additional defect of not providing the desired operating safety for such equipment. It is thus possible that the panel fixing means have a defect preventing the ejection for the expected threshold value of overpressure. In extreme situations, the panel is not ejected at all and the overpressure in the launcher is maintained, leading to a deterioration of the missiles.

Document EP 0 481 851 A1 discloses a closure device which equips the mouth of a chimney of a launcher comprising several chimneys distinct from one another and of circular cross-section. The shutter device comprises two lightweight valves pivoting about a horizontal common axis located in the median plane of symmetry of the chimney. The valves open under the effect of the overpressure caused by the deliberate firing gases of a missile or inadvertent ignition. Each valve is recalled, from its open position to its closed position, by a spring biasing means. In the closed position, the flaps rest on the upper edge of a support sleeve of the flaps surrounding the mouth of the chimney.

Although this document indicates the possibility of using the device described for a launcher having a single central chimney, it turns out, in practice, that this embodiment has different disadvantages. In particular, when the valves cover the entire length of the launcher, they have a large mass. They are then too abruptly opening and closing too fast. When the valve returns to abutment against the sleeve, shocks are generated. In addition, the inertia of the valve makes it oscillates, with a large amplitude, between the open and closed positions. This uncontrolled behavior of the valves leads to gas choking phenomena inside the chimney and premature deterioration of the device. In addition, according to this document of the state of the art, an additional protection element must be placed around the sleeve to protect the shutter device seawater packets, and have a height sufficient to channel the gas s 'flowing through the mouth of the chimney to prevent them from flowing laterally and jeopardize the launch of the missile. Incidentally, the common axis of pivoting valves is located in the center of the flow of propellant gases discharged through the chimney.

The invention therefore aims to solve the aforementioned problems, and in particular those related to the ejection of a panel during a gas emission inadvertent. The invention relates to a closure system for the chimney of a missile launcher, the launcher comprising at least one container adapted to receive at least one missile, and a propulsion gas evacuation pipe comprising a chimney of extraction of the gas, the container being in communication with the pipe during firing of the missile and the pipe being in communication with the atmosphere via the chimney equipped with the shutter system. According to the invention, the closure system comprises at least one panel and a panel retaining means, movable between a closed position and an open position, the retaining means comprising a means for returning the position of opening to the closed position and energy dissipating means resulting from the opening movement and the closing movement. According to particular embodiments, the shutter system comprises one or more of the following characteristics, taken separately or in any technically possible combination: When launching a missile or the untimely emission of gas, the panel moves to the open position as soon as the overpressure of the gases is greater than an opening threshold overpressure, the opening time of the mobile panel being fast, less than 1 second. - When rebalancing pressures in the chimney and the atmosphere, the panel moves to the closed position as soon as the overpressure of the gases is lower than a closing pressure overpressure, the closure time of the movable panel being slow, greater than 5 seconds, preferably greater than 30 seconds. - The retaining means is mechanically equivalent to the parallel association of a biasing element and an energy dissipating element. - The shutter system comprises at least one panel coupled by a hinge-type connection with a frame in the vicinity of one end of the chimney, and at least one retaining means whose one end is coupled by a first pivot connection to frame and a second end is coupled by a second pivot connection to the panel, the axes of the first and second pivot links being parallel and distinct from the axis of the hinge type connection. - The retaining means is housed inside a volume defined by the frame and the panel in the closed position. - The retaining means comprises at least one viscoelastic damper. - The damper includes a viscoelastic gum. - The shutter system comprises two rectangular panels, each panel being coupled to a pair of retaining means. - The frame is provided with stops determining the closed position of the panel. Advantageously, the closure system according to the invention is passive. It opens when an overpressure exerts sufficient force on the panels and closes with return means when the excess pressure fades. It is therefore an automatic operation.

This dispenses with the entire actuation chain (actuator, current source, current amplifier, motor, etc.) necessary for the operation of the doors according to the prior art. The shutter system according to the invention is robust and requires reduced maintenance, which is significant in the maritime context of use of such launchers.

Advantageously, the automatic opening allows operation not only when the overpressure is due to a desired emission of gas, but also during an uncontrollable untimely emission. The shutter system according to the invention then makes it possible to dispense with a fuse holder. Consequently, all the problems inherent in such a fuse holder and in particular the initial phase of calibration of the characteristics thereof are avoided. Finally, the shutter system of the chimney according to the invention is easy to implement, even on existing launchers, and this at a lower cost.

The door system according to the invention is therefore robust, reliable, and ensures a very high operational safety of the launcher. The invention and its advantages 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: FIG. 1 is a diagrammatic sectional view of a missile launcher; - Figure 2 is a side view of an embodiment of the shutter system of the chimney according to the invention, the panels being in the closed position; - Figure 3 is a side view, similar to that of Figure 2, the panels being here in the open position; - Figure 4 is a top view, partial, of the closure system of Figure 3; and, - Figure 5 is a functional representation of the retaining means of a panel; A general description of the operating principle of the passive and automatic sealing system according to the invention will now be made with reference to FIG. 1, on which is shown, schematically, a launcher 1 placed on the deck 15 of a carrier ship . On each side of a plane P of symmetry, the launcher 1 comprises two containers 2 and 3 respectively containing a missile 4, 5. The container 2, respectively the container 3, is closed by doors 6 located in its upper part, in the simplifying hypothesis of a vertical positioning of the launcher. The doors 6 of the container 2, respectively of the container 3, are open during the launching phase of the missile 4, 5. The bottom of the container 2, respectively 3, is equipped with an orifice 7 allowing the flow of the propulsion gases. from the interior of the container 2, 3 to a gas evacuation duct 10. The gas evacuation duct 10 is common to all the containers of the launcher 1. The duct 10 comprises a central chimney 11 arranged vertically between the containers 2 and 3, and which drives the propulsion gases to the outside atmosphere. The upper end, on the atmosphere side, of the chimney 11, hereinafter called mouth 9, is equipped with the shut-off system 14 which is adapted to open as soon as an overpressure inside the chimney 11 exceeds an overpressure opening threshold, and to close when the overpressure passes below a closing threshold overpressure. In the open position of the closure system 14, a communication between the stack 11 and the atmosphere 12 is established allowing the flow of propellant gases from the conduit 10 to the outside of the launcher 1. Once the missile was fired and it came out of the corresponding container, the flow stops. The pressures inside the container, the flue and the chimney are balanced with the atmospheric pressure. The overpressure at the origin of the opening of the closure system 14 decreases and falls below the closure threshold. The shutter system then closes automatically. It resumes its default position in which the conduit 10 is hermetically closed. A preferred embodiment of the closure system 14 will now be described in detail with reference to Figures 2 to 4. In the horizontal plane of the deck 15 of the ship, parallel to the plane of Figure 4, the mouth 9 of the chimney 11 has the shape of an elongated rectangle whose longitudinal axis is located in the plane P of symmetry. The closure system 14 comprises a frame 20, two panels 12 and 13 pivoting, and four dampers as retaining means coupling in pairs each panel 12 or 13 to the frame 20.

The frame 20 frames the mouth 9. It comprises two lateral walls 22 and 23 arranged parallel to the plane P, on either side of the mouth 9. It also comprises two pairs of end walls respectively disposed at each of the longitudinal ends. of the mouth 9, between the side walls 22 and 23, perpendicular to the plane P. A single pair of end walls 25 and 26 is shown, in plan view, in Figure 4: a first wall 25 is located in the vicinity the end of the mouth 9; and a second wall 26 is located away from the end of the mouth 9. An end wall, such as the wall 25, has a generally triangular shape, the base of which rests on a bottom wall 24 of the frame 20 disposed on the bridge 15 and whose apex, opposite the base, is in the plane P.

The panel 12, respectively the panel 13, is a rectangular surface of substantially constant thickness e. The panel 12, 13 has an outer wall 121, 131, an inner wall 123, 133 and peripheral edges.

Each panel 12, respectively 13, is fixed to the side wall 22, 23 of the frame 20 by means of a hinge-type connection 32, 33 integral with the longitudinal peripheral edge 124, 134 of the panel 12, 13. Thus the panel 12, 13 can be moved between a closed position and an open position, by pivoting about the axis A, A 'of the hinge connection 32, 33. Each panel 12, 13 is intended to cover half of the section of the mouth 9 divided along the plane P. In the closed position, the longitudinal peripheral edge 122 of the panel 12, peripheral edge opposite the longitudinal edge 124 carrying the hinge 32, is able to bear against the peripheral edge 132 of the panel 13 peripheral longitudinal edge opposite the peripheral longitudinal wall 134 carrying the hinge 33. As shown in FIG. 3, the peripheral longitudinal edges 122 and 132 are in the plane P and are in contact with one another. In the closed position, the inner wall 123 of the panel 12, respectively 133 of the panel 13, at its longitudinal ends, rests on both the inclined sides of the walls of the wall. 25 and 26 of the frame 20 but also on abutments 28a and 28b, respectively 29a and 29b, disposed on the first and second end walls 25 and 26. Since the inclined sides of these triangular end walls 25 and 26 are an angle α with the plane P, that the inner walls 123 and 133 of the panels 12 and 13 rest on these inclined sides, and that finally the longitudinal peripheral edges 122 and 132 of the panels 12 and 13 are in mutual support, each longitudinal edge device 122, 132 makes an angle with the inner wall 123, 133 of the associated panel. Advantageously, the longitudinal end of the inner wall 123, 133 of the panel 12, respectively of the panel 13, is provided with a pair of grooves 128a and 128b, 129a and 129b. In the closed position, each groove is intended to receive one of the inclined sides of the first and second end walls 25 and 26. This ensures a precise positioning of the panels when they fold down and a good seal in the position of closing. This arrangement explains the reason why the stops 28a and 28b, 29a and 29b are arranged slightly recessed with respect to the inclined sides of the end walls 25 and 26. In the open position, each panel 12, 13 is substantially parallel to the P plane, at right angles to the bridge 15, in the extension of the wall 22, 23 of the frame 20 on which it is fixed. In this position, the panels 12 and 13 being disposed on either side of the mouth of the chimney, the ejected gases are channeled vertically. In particular, they do not flow laterally towards the missile being launched. This avoids an additional piece serving as a side screen ejected gas. The panels 12 and 13 have a length slightly greater than the length of the mouth 9. They extend between the second end walls 25 of the frame 20 which are the end walls furthest from the mouth 9 Thus, the panels 12 and 13 cover areas of the bridge 15 located on either side of the mouth 9. The panels 12 and 13, the pair of walls 25 and 26 and the bridge 15 thus delimit a volume 17 forming a housing for a damper 18 of the panel 12 and a damper 19 of the panel 13. Similarly, another volume (not shown), located on the side of the other longitudinal end of the mouth 9, forms a housing for the other damper of the panel 12 and the other damper of the panel 13.

Each damper 18, 19 is a viscoelastic rubber damper in the form of a cylinder 181, 191 and a rod 182, 192 slidable inside the cylinder 181, 191. The cylinder 181, 192 comprises means known to those skilled in the art to provide a function of returning the extended position to the retracted position, and a function of dissipating the energy of the movement between the two positions, extended and retracted. The cylinder 181 is coupled to the side wall 23 of the frame 20 by a pivot connection 183 of axis B '. The end of the cylinder 181, opposite the rod 182, comprises two lugs 186 and 187, diametrically opposite, arranged on the outer wall of the body of the cylinder 181. Support parts 231 and 232 are fixed, for example by welding, to right angle on the side wall 23 and on the bottom 24 of the frame 20, so as to be disposed on either side of the body of the cylinder 181. The lugs 186 and 187 are received in corresponding bores formed in the two pieces of 231 and 232 to form the pivot connection 183. The end of the rod 182, opposite the cylinder 181, is secured to the panel 12 by a pivot connection 184 of axis B. For this, the end of the rod 182 has a clevis portion inserted between two lugs 126 and 127 fixed on the inner wall 123 of the panel 12. The rod 185 of the pivot connection 184 is introduced through the aligned bores of the ear 126, the yoke of the stem 182 and ear 127.

The axes B and B 'of the pivot links 184 and 183 are parallel, but distinct, from the axis A of the hinge connection 24 around which the panel 12 rotates. The damper 19 of the panel 13, articulated around the axes C and C 'pivot links 193 and 194, is similar to the damper just described. Also, it will not be described in detail, but it will be noted simply that the dampers 18 and 19 are placed head to tail in the housing 17. Thus arranged, the dampers 18, 19 are able to apply a restoring torque on the panel 12, 13 to which they are coupled to move it from the open position to the closed position and vice versa.

FIG. 5 schematically represents a mechanical equivalent of the retaining means that may be suitable for the invention. In this figure, there is the hinge link 32 between the frame 20 and the panel 12. There is also the pivot connection 183 between the frame 20 and the retaining means 18 and the pivot connection 184 between the retaining means 18 and the panel 12. The retaining means 18 is equivalent to the parallel association of a return element 18a and a dissipation element 18b. In a preferred embodiment, the retaining means used are constituted by a viscoelastic rubber damper 18, 19. Shocks of this type are known and are for example marketed by the company DOMANGE JARRET.

However, other types of retaining means could be used as soon as they have the functions shown schematically in FIG. 5. It will be noted that the return element converts a kinetic energy or a work into a potential energy. that he can then restore. Any mechanical device that can have these physical properties may be suitable for the invention. This is particularly the case of a spring that stores energy in the form of elongation or compression. Ain-si, alternatively the retaining means can take the form of a hydraulic cylinder, as a dissipation element, associated with a spring, as a return element, operating in extension or in compression in function positioning the spring on the hydraulic cylinder rod.

The operation of the shutter system in opening and closing will now be described in detail. The establishment of an overpressure in the chimney 11 results in the application of a force on the inner wall 123, respectively 133, of the panel 12, 13. Each panel being retained by a hinge connection 32, 33, the force generated has a torque relative to the axis A, A 'adapted to rotate the panel 12, 13. Under the effect of this pair, the panel 12, 13, initially in its closed rest position, opens up to an open position in which it is substantially at right angles to the deck 15 of the ship (see Figure 3). This opening is extremely fast and takes less than a second. In a digital application by way of example, the panel 12, respectively the panel 13 has a length of 2200 mm and a width of 170 mm leading to a surface of 0.4 m2. The panel 12, 13 has a thickness e for example of 30 mm. Being made of steel, the mass of the panel 12, 13 is thus of the order of 80 kg. When it is caused by the propulsion gases of a deliberately fired missile, the overpressure, typically 2.9 bar, generates an opening taking place in an opening time of 0.04 s. In this fast opening phase, the role of the damper 18 is to brake the panel 12 as it approaches its position at 90 ° so as to prevent back-offs and to avoid oscillations around this position final. The dissipation element 18b of the damper 18 acts by dissipating a fraction of the mechanical work of rotation of the panel 12 produced by the overpressure. The other fraction of the mechanical work is absorbed by the return element 18a of the damper 18. When the overpressure which caused the opening of the panels 12 and 13 drops to the zero value and returns below a value threshold, the dampers 18, 19 generate the closing movement. Indeed, the potential energy accumulated in the return element 18a is restored in the form of a return torque for folding the panel 12, 13 to the closed position. So that this closing movement is not too fast, to allow in particular the good ventilation of the exhaust duct 10 and its chimney 11, most of the potential energy released by the damping 18 is dissipated by the part of dissipation 18b. The characteristic constants of the equivalent recall and dissipation elements are determined to obtain a slow closure typically of the order of one minute and 2 minutes in the digital application selected. They are also defined to define a threshold value of the overpressure at the opening and for a threshold value of the overpressure at closing. Alternatively, the damping means may be located outside the volume 17. In this embodiment, the return means are then coupled with the outer face 124, respectively 134 of the panel 12, 13. But they are then exposed to external aggression. Another variant would be to couple not the rod 182 of the return means 18 to the panel 12, but the cylinder portion 181.

Of course, the invention is not limited to a closure system for a launcher arranged vertically, provided with a central chimney. Indeed, the relative orientation of the launcher, as well as the orientation and the disposition of the chimney with respect to the containers, can be modified without departing from the scope of the invention. Thus the number of constituent parts of the closure system according to the invention is reduced. The means used are all passive so that the shutter system of the invention does not require a source of energy to operate. All this gives it great strength and increased operational safety. Above all, the shutter system described operates automatically not only in the desired trigger mode, that is to say when the gases come from the controlled firing of a missile, but also during an untimely emission of gas.

Claims (1)

CLAIMS1.- Shutter system (14) for chimney of a missile launcher, the launcher (1) comprising at least one container (2, 3), adapted to receive at least one missile (4, 5), and a propulsion gas evacuation pipe (10) comprising a gas extraction chimney (11), the container being in communication with the pipe during firing of the missile and the pipe being in communication with the atmosphere (12) via the chimney equipped with said closure system, characterized in that the closure system comprises at least one panel (12, 13) and a panel retaining means (18, 19) movable between a closed position and a position opening, the retaining means having biasing means (18a) from the open position to the closed position and energy dissipating means (18b) resulting from the opening movement and the closing movement. 2.- shutter system (14) according to claim 1, characterized in that it is adapted so that when launching a missile or the inadvertent emission of gas, the panel (12, 13) moves to the open position as soon as the overpressure of the gases is greater than an overpressure opening threshold, and in that the opening time of the movable panel is fast, less than 1 second. 3.- System according to claim 1 or claim 2, characterized in that it is adapted so that during rebalancing pressures in the chimney (11) and the atmosphere, the panel (12, 13) moves towards the closing position as soon as the overpressure of the gases is lower than an overpressure closing threshold, and in that the closing time of the movable panel is slow, greater than 5 seconds, preferably greater than 30 seconds. 4. A closure system (14) according to any one of the preceding claims, characterized in that said retaining means (18, 19) is mechanically equivalent to the parallel association of a biasing element ( 18a) and an energy dissipation element (18b). 5. Shutter system (14) according to any one of the preceding claims, characterized in that it comprises at least one panel (12, 13) coupled by a hinge type connection (32, 33) with a frame (20) adjacent an end (9) of the chimney (11), and at least one retaining means (18, 19) having a first end coupled thereto by a first pivot connection (183; 193) to the frame and a second end is coupled by a second pivot connection (184; 194) to the panel, the axes (B, B '; C, C') of the first and second pivot links being parallel and distinct from the axis (A; A ' ) of the hinge type connection. 6. A closure system (14) according to any one of the preceding claims, characterized in that said retaining means (18, 19) is housed inside a volume (17) delimited by the frame ( 20) and said at least one panel (12, 13) in the closed position. 7. A closure system (14) according to one of the preceding claims, characterized in that said retaining means comprises at least one viscoelastic damper (18, 19) 8. System according to claim 7, characterized in that said damper comprises a viscoelastic gum. 9.- shutter system (14) according to any one of the preceding claims, characterized in that it comprises two panels (12, 13) rectangular, each panel being coupled to a pair of retaining means, the axes ( A, A ') of each of the two hinge type connections being on either side of the chimney (11). 10.- shutter system (14) according to any one of claims 5 to 9, characterized in that said frame (20) is provided with stops (28a, 28b, 29a, 29b) determining the closing position of said to least one panel (12, 13).