UNDERSEA EJECTION DEVICE EMPLOYING PRESSURE BALANCING VALVE

Abstract

An apparatus for ejecting devices from a submarine that includes a tank having an interior cavity, wherein this interior cavity has a proximate side and a distal side. A piston having a proximate face and a distal face is positioned transversely in the interior cavity of the tank. A shaft extends from the piston to the proximate side of the interior cavity to reciprocate the piston axially in the interior cavity of the tank between a proximate and a distal position. A gas input is in operative communication with the proximate side of the interior cavity. A device ejecting tube is in operative communication with the distal side of the interior cavity. A gaseous fluid is injected into the device ejecting tube to reduce cavitation and thereby moderate shock and vibration loads and noise resulting from the ejection of the device.

Description

STATEMENT OF GOVERNMENT INTEREST

[0001] The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

[0002] Not applicable.

BACKGROUND OF THE INVENTION

[0003] (1) Field of the Invention

[0004] The present invention relates to apparatus for ejecting devices from submersible vessels and more particularly to an ejection device which prevents water hammer.

[0005] (2) Brief Description of the Prior Art

[0006] With the exception of the SSN 21 Class submarine, all existing and future submarine small device launch systems utilize a basic design concept which was developed in the early sixties. In operation, an impulse tank assembly is connected to a high pressure air source on one side and to a 3-inch launch tube on the other. When it is desired to fire a device from the launch tube, high pressure air is ported to the impulse tank. This forces a piston within the tank to push water on the other side of the piston to the breech end of a device in the launch tube. This results in the device being ejected from the launch tube.

[0007] In operation, as the piston reaches its end of stroke, preventive measures are necessary to avoid metal to metal contact between the piston and the impulse tank. Such contact not only results in shock loading the system's hardware, but also results in a high level of airborne and waterborne acoustic noise. In order to reduce the effect of the end of stroke impact, rubber bumpers are incorporated into both end caps of the impulse tank, and the water side of the impulse tank incorporates deceleration disks into its design. The deceleration disks work in conjunction with the conical end of the shaft to restrict fluid flow from moving from the water side of the piston to the launch tube at the end of its power stroke. As the piston assembly moves toward the end of its stroke, more and more disks are effectively sealed against fluid flow by the cylindrical section of the shaft cone. This results in higher and higher pressure being built up on the water side of the piston. This pressure counteracts the high air pressure on the air side of the piston, in an attempt to cushion the last portion of piston's travel. However, in spite of the piston deceleration control effected by the bumper and the deceleration disks, the column of water in the pipe leading to the launch tube tends to continue to flow in the direction of the launch tube. This fluid momentum results in a low pressure area being created in the area of the launch pipe, closest to the impulse tank. The low pressure area rapidly stops all flow in the pipe thereby creating cavitation or water hammer. The water hammer is detrimental to the system with respect to the shock and vibration loads transmitted to mechanical parts. Furthermore, the ship's position can be readily detected from the noise created by the water hammer.

[0008] Heretofore, this water hammer was relatively inconsequential as the 3-inch launcher was primarily used for distress buoys, marker buoys and other devices which themselves revealed the ship's position. The 3-inch launcher, however, is now used for a myriad of devices including bathythermographs, time delay jammers, decoy devices and other devices when a covert launch is desirable.

[0009] The prior art discloses various apparatus for ejecting devices from submarines and other submersible vessels.

[0010] U.S. Pat. No. 3,298,278 to Barakauskas, for example, discloses a standpipe device for a missile launching system. There is a tank for holding a quantity of water. A gas generator having an exhaust nozzle extends from the top of the tank for applying gas to the tank. A discharge pipe connects to the bottom of the tank.

[0011] U.S. Pat. No. 4,575,330 to Schmitt discloses an expelling mechanism adapted for use with discharge tubes and drain tubes of submarines for ejecting a weapon by compressed air including a chamber formed with an outlet opening, and adapted to substantially communicate selectively with a storage container holding compressed gas, a discharge valve which may be moved towards the opening in a closing direction, and away therefrom in an opening direction at a selectable opening velocity, and a hydraulic control device for controlling the movement of the discharge valve. The hydraulic control device includes a cylinder adapted to be filled with hydraulic fluid, a piston reciprocally movable along a stroke within the cylinder, and partitioning the cylinder into two cylinder chambers, an overflow channel establishing communication between the cylinder chambers, and a connecting device connecting the discharge valve with the hydraulic control device. The outlet opening and the overflow channel have cross sections, which are variable in dependence of the stroke, respectively, so that the outlet opening increases as the discharge valve moves in the opening direction. The opening velocity of the discharge valve may be controlled, and different respective cross sections of the overflow channel may be set in dependence of the stroke.

[0012] U.S. Pat. No. 5,099,745 to Hubbell et al. discloses a low-noise, low pressure torpedo launching system having specially designed ports connecting a water cylinder to an impulse tank and to a method for designing such ports. The invention uses specially designed C-shaped water cylinder discharge ports to provide a continuous and minimized pressure gradient as the ports are closed by the water piston. The resulting controlled deceleration of the water piston reduces operational noise, reduces mechanical stresses and eliminated the need for auxiliary dashpot components.

[0013] U.S. Pat. No. 5,123,370 to Woidich et al. discloses a blowout system for ejection and discharge tubes of submarines, which permits an ejection of weapons from a torpedo tube, said weapons not having an own propulsion, and which prevents the intrusion of water after the blowout operation is terminated. The system is subsequently installable as a compact unit and has an outlet opening, which is closed by a check valve. The outlet opening is continued by a buffer tube, a blowout valve arranged between a compressed-gas container and said buffer tube being provided for supplying said compressed gas.

[0014] U.S. Pat. No. 5,165,360 to Moody discloses an apparatus that is capable of a rapid firing sequence for an underwater dual barrel launcher. An air cylinder assembly drives a water piston housed in a water cylinder in either of two opposing piston stroke directions. The water cylinder is continually supplied and balanced with sea pressure. A piston stroke in a first direction pressurizes impulse water in the water cylinder that is then supplied to a first launch tube of the dual barrel launcher. A piston stroke in an opposing second direction again pressurizes impulse water in the water cylinder that is then supplied to a second launch tube. Thus, each opposing piston stroke is a power stroke.

[0015] U.S. Pat. No. 5,363,791 to Stallart, III discloses a system for launching a weapon from a submarine comprising a tube for receiving the weapon, a ram assembly for launching the weapon, an actuator for actuating the ram assembly and a volume within which water is received, the weight of the water received in the volume being approximately equal to the weight of the expended weapon. The ram assembly includes a ram head for transmitting a launching force to the weapon and a plurality of telescoping cylinders, the telescoping cylinders extending within the tube when the weapon is launched. The volume within which the water is received is formed between the tube and the telescoping cylinders in their extended position.

[0016] U.S. Pat. No. 5,834,674 to Rodriguez et al. discloses a device for ejecting a weapon from a submersible launch tube including a front door and a rear door. The device also has holder elements for holding the inner tube in the launch tube and a pump device for circulation fluid between a front and a rear of the launch tube and the inner tube at a high flow rate.

[0017] A need still exists, however, for an improved way of ejecting a device with less noise and greater efficiency.

SUMMARY OF THE INVENTION

[0018] It is an object of the present invention to provide an improved apparatus and method for quietly ejecting a device from a submarine or other submersible vehicle.

[0019] It is a further object of this invention to provide a modification for existing systems which can be incorporated into the system with a minimal expenditure of funds and a minimal impact on existing ships hardware so that ship arrangement problems would not be introduced.

[0020] This and other objects are accomplished by the present invention, which is an apparatus for ejecting devices from a submarine that includes a tank having an interior cavity. A piston is positioned in the interior cavity of the tank. A shaft extends from the piston to a first side of the interior cavity allowing reciprocal movement of the piston in the interior cavity of the tank. A gas input is in communication with the first side of the interior cavity. A device ejecting tube is in communication with a second side of the interior cavity. At the appropriate stage of ejection, a gaseous fluid is injected into the device ejecting tube to reduce cavitation and thereby moderate shock and vibration loads and noise resulting from the ejection of the device.

[0021] The present invention also encompasses introduction of a small amount of air into the system automatically at the time when water hammer would occur in the ejecting tube. By introducing this air into the ejecting tube, the column of water in the ejecting tube is made more compliant. It has been demonstrated that by introducing small volumetric fractions of air into the system in an order of 1% or less, wave propagation speed can be drastically reduced, because the air bubbles created by the introduced air will expand and contract while water does not.

[0022] Preferably, the present invention includes an air-side pipeline, a water-side pipelines and a special check valve between the pipelines. In the “at battery position”, sea water pressure holds the impulse tank piston in a position where the impulse tank is filled with sea water and holds the check valve closed. In the “firing position”, the air pressure is regulated to be a fixed amount higher than the sea pressure corresponding to the ship's depth. The air pressure is high enough to move the impulse tank's piston, but it is not high enough to unseat the check valve, as the check valve's spring continues holding the valve closed. At the “end of the power stroke position”, the piston is decelerated by the impulse tank's deceleration system and the water-side pipeline drops in pressure. The pressure in the air-side pipeline overcomes the check valve's spring and air flows through the water-side pipeline into the launch tube. Once the source of high pressure air is shut off, the impulse tank piston returns to its “at battery position” as a result of sea pressure forcing it in that direction. Likewise, the check valve closes, preventing seawater from flowing into the air-side pipeline.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Other objects, features and advantages of the present invention will become apparent upon reference to the following description of the preferred embodiments and to the drawing, wherein corresponding reference characters indicate corresponding parts in the drawing and wherein:

[0024] FIG. 1 is a vertical cross sectional view of an apparatus representing a preferred embodiment of the present invention;

[0025] FIGS. 2a-2d are successive schematic views of the apparatus shown in FIG. 1 which illustrates a preferred embodiment of the method of the present invention; and

[0026] FIGS. 3a-3d are successive cross sectional views respectively of circles 3a-3d respectively in FIGS. 2a-2d.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0027] Referring to FIG. 1, an impulse tank 10 includes a proximate end wall 12, a distal end wall 14 and a peripheral longitudinal wall 16, which extends between the proximate end wall 12 and the distal end wall 14. The proximate end wall 12 is connected to the peripheral longitudinal wall 16 by longitudinal bolts as at bolts 18 and 20. The distal end wall 14 is connected to the peripheral longitudinal wall 16 by means of longitudinal bolts as by bolts 24 and 26. On the inner surface of the proximate end wall 12 there are proximate end cushioning bumpers 28 and 30. On the distal end wall 14 there is a distal end cushioning bumper ring 32. The entire assembly rests on a base including base legs 36 and 38. The distal wall 14 has a longitudinal distal wall central aperture 40. Positioned about this central aperture 40, there are deceleration discs as at discs 42 and 44 supported on bolts 46 and 52. There is an air inlet aperture 54 in the proximate end wall 12. This air inlet aperture 54 connects to an air pipe 56. The impulse tank 10 has an interior recess 58 in which a piston 60 is transversely positioned. This piston 60 has a proximate air side face 62 and a distal water side face 64. The piston 60 also has a central aperture 66 in which a longitudinal shaft 68 is mounted. Piston shaft 68 extends through an aperture 70 in the proximate end wall 12. The shaft 68 also has a distal flange 72 on which a shaft cone 74 is positioned so as to be located in the central aperture 40 of distal wall 14. A discharge tube flange 76 is mounted on the distal face of distal end wall 14 by means of longitudinal bolts as at bolts 78 and 80. Extending in a distal direction from this discharge tube flange 76, there is a discharge tube 82, which will ordinarily be 3 inches in diameter. As is conventional, a device (not shown) will be positioned to be discharged from the muzzle (not shown) in the extended portion of the tube 82. It will be understood that the apparatus described to this point is essentially conventional and that the novel features are described in the following paragraphs.

[0028] An air side line 84 extends from air pipe 56 to check valve 86. This check valve 86 includes a chamber 88 with a proximate shoulder 90 and a distal shoulder 92. A valve body 94 includes a proximate cylindrical section 96 having the same diameter as line 84 and a widened flange section 98 with an axial bore 100. One or more supports (not shown) maintain proximate cylindrical section 96 position with respect to widened flange section 98. Between the valve body 94 and the distal shoulder 92 there is an axial helical spring 102, which is shown in a compressed condition. Spring 102 biases valve body 94 against proximate shoulder 90. A water side line 104 extends between the check valve 86 and the discharge tube 82. It will be understood that in FIG. 1, the position of the piston 60 is shown at the end of the power stroke position, although the piston 60 is axially moveable throughout the interior cavity 58 of impulse tank 10.

[0029] The mode of operation of impulse tank 10 described above is described as follows. Referring to FIGS. 2a and 3a, impulse tank 10 is shown with piston 60 in the proximate position 106. A low pressure air space 108 is positioned to the proximate air face side of the piston 60, while a high pressure water space 110 is positioned to the distal water face of the piston 60. In FIG. 3a, spring 102 pushes valve body cylindrical section 96 into line 84 preventing flow through valve 86. This is the “at battery position” of impulse tank 10. Referring to FIGS. 2b and 3b, high pressure air is then provided through air pipe 56 to move the piston 60 through a medial position 112. In this position, a high pressure air space 114 is positioned on the proximate air face of the piston 60 while a relatively lower pressure water space 116 is provided at the distal side of the piston 60. The water space 116 results from movement of piston 60 to medial position 112. As is shown in FIG. 3b in “firing position,” plug 94 of the check valve 86 is positioned so that the cylindrical section 96 is still positioned in the air side line 84. At this stage, the axial helical spring 102 is still positioned in an extended position between plug 94 and the distal shoulder 92.

[0030] Referring to FIGS. 2c and 3c, the end of the power stroke position is shown wherein the piston 60 is in a distal position 118 with a high pressure air space 120 adjacent its proximate air side face 62 and a very low pressure water and air mixture space 122 positioned adjacent its distal water side face 64. This very low pressure is much lower than the ambient pressure of water in the at battery position and firing position. The low pressure is caused by the momentum of the water traveling out of discharge tube 82. The shaft cone 74 is positioned at this stage in the discharge tube 82, and in this stage the device (not shown) is also ejected from the tube. Air also flows through air side line 84 with sufficient pressure to move the cylindrical section 96 of the plug 94 from the air side line 84 into the chamber 88 and compress the axial helical spring 102 as is shown in FIG. 3c. Air then moves through water side line 104 to the discharge tube 82 to be injected into the water 124 at the time of the discharge of the device (not shown). This stage in the operation of impulse tank 10 is the “end of power stroke position”.

[0031] Referring to FIGS. 2d and 3d, a “return to battery position” occurs as high pressure air is no longer provided in air pipe 56 so that the piston 60 returns to a medial position 112 with a low pressure air space 126 on its proximate air side face 62 and a high pressure water space 128 on its water side space. The helical axial spring 102 in the check valve 86 also expands to force the cylindrical section 96 of plug 94 back into the air side line 84 so as to close the check valve 86.

[0032] Over the four stages of impulse tank 10 operation, as described above, the volume fraction of air injected into discharge tube 82 at the “end of power stroke” position is preferably in the range of 1% to 3% of the total volume of the discharge tube. The volume fraction is the average percent of gas in the discharge tube as compared to the tube total volume.

[0033] Those skilled in the art will appreciate that in an embodiment alternate, pipeline lengths between the check valve and water pipe may be minimized to improve operation.

[0034] It will also be appreciated that in another alternate embodiment equivalent check valves configurations could be utilized.

[0035] It will also be appreciated that in another alternate embodiment, a control circuit could be added for operational control of the check valve, if it was determined to be necessary or desirable.

[0036] It will also be appreciated that that in another alternate embodiment, features described could be combined with other system enhancement modifications, as, for example, downstream of the impulse tank it may be desirable to add an air capture tank to prevent air bubbles from reaching the launch tube.

[0037] It will be appreciated that the apparatus and method of the present invention provides a means to quiet the launch system to effect advantages in component shock and vibration loads.

[0038] It will also be appreciated that the method and apparatus provides a modification which can be incorporated into existing and future submarine design at low cost as the pipelines introduced may be in the order of {fraction (1/8)} inch in diameter.

[0039] It will also be appreciated that the operation of the system as described above will be automatic with no need for any timing control system.

[0040] While the present invention has been described in connection with the preferred embodiments of the various figures, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiment for performing the same function of the present invention without deviating therefrom. Therefore, the present invention should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims.

Claims

1. An apparatus for ejecting a device comprising:

a tank having a proximate side and a distal side with an interior cavity defined in said tank;

a piston having a proximate face and a distal face and positioned transversely in said tank interior cavity, said piston being capable of reciprocal motion in said tank interior cavity between said proximate side and said distal side;

a gas input means in fluid communication with the proximate side of said tank interior cavity;

a device ejecting means in fluid communication with the distal side of said tank interior cavity; and

a gas injecting means in communication with the device ejecting means.

2. The apparatus of claim 1 wherein said gas injecting means comprises:

an air-side pipeline joined in communication with said gas input means;

a water-side pipeline joined in communication with said device ejecting means; and

a valve positioned in communication between said air-side pipeline and said water-side pipeline, said valve preventing flow from said water-side pipeline to said air-side pipeline and permitting flow from said air-side pipeline to said water-side pipeline when pressure in said air-side pipeline exceeds pressure in said water-side pipeline.

3. The apparatus of claim 2 wherein said valve comprises:

a valve housing joined in communication between said air-side pipeline and said water-side pipeline and defining a chamber therein;

a valve body positioned reciprocally in said valve housing chamber, said valve body being movable from a first position blocking communication through said valve housing to a second position permitting communication through said valve housing when pressure in said air-side pipeline exceeds pressure in said water-side pipeline; and

a spring interposed between said valve body and said valve housing, said spring biasing said valve body toward said first position.

4. An apparatus for ejecting a device comprising:

a tank having a proximate wall, a distal wall and a peripheral wall extending between said distal wall and said proximate wall, and an interior cavity being defined within said tank by said walls, said proximate wall having a shaft aperture and a gas port therethrough, said distal wall having an ejection fluid communication port therethrough;

a piston having a proximate face and a distal face and positioned transversely in said tank interior cavity, said piston being capable of reciprocal motion in said tank interior cavity between said proximate wall and said distal wall;

a piston shaft joined to said proximate face of said piston and extending through said shaft aperture in said tank;

a gas input means in fluid communication with said gas port of said tank;

a device ejecting tube in fluid communication with said ejection fluid communication port; and

a gas injecting means in fluid communication with the device ejecting tube.

5. The apparatus of claim 4 wherein said gas injecting means comprises:

an air-side pipeline joined in communication with said gas input means;

a water-side pipeline joined in communication with said device ejecting tube; and

a valve positioned in communication between said air-side pipeline and said water-side pipeline, said valve preventing flow from said water-side pipeline to said air-side pipeline and permitting flow from said air-side pipeline to said water-side pipeline when pressure in said air-side pipeline exceeds pressure in said water-side pipeline.

6. The apparatus of claim 5 wherein said valve comprises:

a valve housing joined in communication between said air-side pipeline and said water-side pipeline and defining a chamber therein;

a valve body positioned reciprocally in said valve housing chamber, said valve body being movable from a first position blocking communication through said valve housing to a second position permitting communication through said valve housing when pressure in said air-side pipeline exceeds pressure in said water-side pipeline; and

a spring interposed between said valve body and said valve housing, said spring biasing said valve body toward said first position.