Annular tanks and vehicles

Abstract

To provide an alternative toroidal tank which enables a long term storage of propellants and a vehicle adapted to be used for long term missions.SOLUTION: The invention discloses a toroidal tank for a vehicle. The toroidal tank is designed as a bladder tank for storage of bi-propellant, and a space craft.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a toroidal tank and a vehicle such as a spacecraft according to the preamble of claim 1. [Background technology]

[0002] Annular tanks for vehicles such as spacecraft for storing one propellant are well known. Also known are annular tanks for spacecraft having two compartments for storing two different propellants (liquids). Known annular tanks include a shell defining a radially inner ring tank and a radially outer ring tank. Both ring tanks are separated by an inner cylindrical wall. Summary of the Invention [Problem to be solved by the invention]

[0003] It is an object of the present invention to provide an alternative annular tank that allows for long-term storage of propellant and a vehicle suitable for use on long-duration missions. [Means for solving the problem]

[0004] This object is achieved by an annular tank with the features of claim 1 and by the 8 This is achieved by a vehicle having the following features: Advantageous embodiments are disclosed in the dependent claims, the description and the drawings.

[0005] According to the present invention, an annular tank for a vehicle includes at least one bladder defining a liquid compartment for storing a liquid. The annular tank is thus designed as a bladder tank having at least one bladder for storing a liquid, such as a propellant. The bladder of the present invention allows for long-term storage of the propellant.

[0006] Annular tanks are particularly suited for use with highly concentrated hydrogen peroxide (HTP, H2O2), including high concentrations, by mitigating HTP decomposition problems. Exemplary bladder materials are processable fluoropolymers such as fluorinated ethylene propylene (FEP) and perfluoroalkoxyalkane (PFA). Materials are primarily selected for their temperature resistance and permeability to liquids and gases. FEP and PFA exhibit high temperature resistance in the range of -200°C to +200°C, thereby covering the bladder's operating temperature with ease. Being a true thermoplastic, FEP is the material of choice for bladders because it can be vacuum formed and welded. In some cases, it is advantageous for the bladder to be liquid-tight but gas-permeable.

[0007] Preferably, a plurality of individual bladders are provided, each defining an individual liquid compartment. Such an annular tank allows for long-term storage of more than one liquid. For example, an annular tank may be used to store multiple propellants, such as for vehicles requiring the ability to perform complex maneuvers in various orientations.

[0008] In a preferred embodiment, the bladder compartments are arranged in a ring configuration, e.g., as a radially inner ring and a radially outer ring. Each ring forms an individual fluid compartment, each with its own individual bladder tank volume. The individual bladder tank volumes of the radially inner bladders define a joint radially inner tank volume, and the individual bladder tank volumes of the multiple radially outer bladders define a joint radially outer tank volume. By providing multiple smaller bladder tank volumes and then connecting them to a larger bladder tank volume, migration of propellant fluid around the annulus is prevented. Preferably, there are more (at least as many) radially outer bladders than radially inner bladders.

[0009] To combine the tank volumes of each individual bladder into a larger tank volume, the bladders forming the joint tank volume are fluidly connected to a single collection line. In one embodiment, a first outer collection line and a second outer fluid collection line are provided. These collection lines establish a fluid connection between each bladder. This means that some bladders are fluidly connected to the first outer collection line, and other bladders are fluidly connected to the second outer collection line. Preferably, the collection lines have a ring shape. This allows for a simple and compact installation of the collection lines in the annular tank.

[0010] Because the annular tank shape does not have a clearly defined bottom position, each bladder is equipped with a lower, inner collection tube that is fluidly connected to either the first collection line or the second collection line.

[0011] Preferably, the inner collection pipes extend circumferentially around the annular tank and open at their opposite end faces and through continuous openings between the end faces. The collection pipes extend at the bottom of each bladder, thereby having multiple openings along their entire length. Branch lines in fluid communication with each collection line are preferably positioned centrally of the collection line.

[0012] To keep the bladders in place, especially in the event of axial back-acceleration, the lower halves of the bladders are anchored to their surrounding structure, such as the inner surface area of ​​the annular tank shell. This can be achieved, for example, by an etching operation on the fluoropolymer side. Their upper halves remain free to allow for propellant depletion and expulsion. If necessary, several baffles can be added to the interface between the two bladders, e.g., 3D printed, to support side loads during launch and ensure bladder rigidity. Such isolation baffles also limit bladder-to-bladder interaction, thus allowing dynamic validation of the bladder structure at only the single-component level, e.g., a qualification bladder, thereby providing the advantage of reducing risk to the tank assembly level, e.g., a full system demonstrator, with multiple bladder devices inside.

[0013] Each bladder (fluid compartment) may be integrated with a pressurizing device to pressurize the compartment to support the collapsing bladder and force the propellant into the vehicle's propulsion system.

[0014] The use of hydrogen peroxide (HTP, HO) as a space propellant is complicated, especially due to the decomposition of the liquid and the resulting increase in oxygen. Therefore, the accumulation of gaseous oxygen inside the bladders is inevitable. Therefore, it is preferable that at least some bladders, especially those intended for storing gases such as HTP, are integrated into the pumping system.

[0015] A vehicle of the invention has an annular tank according to the invention. The vehicle may be a spacecraft, a launcher stage, or the like, and is capable of long-duration missions.

[0016] In the following, preferred embodiments of the present invention will be described with reference to the accompanying drawings. It will be understood that the various elements and parts are depicted by way of example only and may be optional and / or combined differently than depicted. Reference numerals for related elements are used generically and are not necessarily redefined for each figure. For clarity, only some of the same elements are given reference numerals. Terms such as upper and lower refer to the orientation of the annular tank at that segment in the drawing. The following drawings are shown diagrammatically. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view of an annular tank according to the present invention. [Figure 2] FIG. 1 is a perspective bottom view of the bladder of the annular tank. [Figure 3] FIG. 1 is an exploded view of the bladder of the annular tank. [Figure 4] FIG. 1 is a perspective view of an arrangement of radially inner and outer bladders of an annular tank. [Figure 5] FIG. 13 shows a collection tube inside the bladder of the annular tank. [Figure 6] FIG. 10 is a view of an enlarged end section of a collection tube. [Figure 7] FIG. 10 is a diagram of the positioning of the pressurization tube and the breather tube. DETAILED DESCRIPTION OF THE INVENTION

[0018] 1 shows a cross-sectional view of an annular tank 1 of the present invention serving as a bladder tank. The annular tank 1 can be used as a bipropellant for vehicles such as spacecraft and launcher stages. Exemplary bipropellants are kerosene and H2O2.

[0019] The annular tank 1 has a radially inner ring-shaped tank section 2 and a radially outer ring-shaped tank section 4. Each tank section 2, 4 provides a tank capacity for storing a propellant. For example, the radially inner ring-shaped tank section 2 stores propellant RFI, and the radially outer ring-shaped tank section 4 stores hydrogen peroxide (HTP, HO).

[0020] Each tank section 2,4, and the annular tank 1 itself, includes a plurality of bladders 6,8 positioned side by side in a radially inner region of the shell 10 of the annular tank 1 and in a radially outer region of the shell 10. In this embodiment, the interior of the shell 10 is divided into two interior regions by a cylindrical wall 12, thereby forming the ring-shaped tank sections 2,4.

[0021] Propellant is supplied to the vehicle's propulsion system via outer collection lines 14,16.

[0022] 2 and 3, each bladder 6, 8 is designed as an individual bladder tank that defines a liquid compartment. Each radially inner bladder 6 defines an individual liquid compartment with an individual tank volume, and each radially outer bladder 8 defines an individual liquid compartment with an individual tank volume. The bladders 6, 8 are configured to conform to the annular shape of the annular tank 1 when installed.

[0023] The radially inner bladders (liquid compartments) 6 are fluidly connected to each other and define a (joint) radially inner tank volume. The radially outer bladders (liquid compartments) 8 are also fluidly connected to each other and define a (joint) radially outer tank volume.

[0024] The respective fluid connections are established by outer collection lines 14, 16. The collection lines 14, 16 are ring-shaped and positioned concentrically (coaxially) below the annular tank 1. The radially inner collection line 14 is in fluid communication with the radially inner bladder 6 via a respective branch line 22, and the radially outer collection line 16 is in fluid communication with the radially outer bladder 8 via a respective branch line 24. The integration of the collection lines 14, 16 with the respective propulsion devices of the vehicle is achieved by discharge pipes 26, 28.

[0025] As shown in Figure 4, the radially inner bladder 6 and the radially outer bladder 8 are positioned inside the shell 10 (not shown) of the annular tank 1 by placing the radially inner bladder 6 with its convex rear surface 30 against the concave front surface 32 of the radially outer bladder 8. As also shown in Figure 4, each bladder 6, 8 is provided with an inner surface 34.

[0026] As can be seen in more detail in Figures 5 and 6 with respect to bladder 6, collection tube 34 is positioned at the bottom of bladder 6 and follows the inner contour of bladder 6. Collection tube 34 extends the entire extent of bladder 6 in the circumferential direction of annular tank 1. It opens medially at its end faces 36, 38 via a plurality of openings 40 through collection tube 34. Located medially between end faces 36, 38 is a port 42 adapted to receive each branch line 22 of radially inner collection line 14.

[0027] 7, the bladders 6, 8 are secured by their lower halves 44 to the inner surface region 46 of the shell (the bladder halves below the dashed horizontal line 48). By their upper halves 50, the bladders 6, 8 are not secured. When the bladders 6, 8 are filled with propellant, their upper halves 50 abut against the inner surface 46 of the shell 10. During removal of the propellant, the upper bladder halves 50 drop toward their lower halves 44. The bladder 6 collapses.

[0028] Exemplary bladder materials are fluorinated ethylene propylene (FEP) and perfluoroalkoxyalkane (PFA).

[0029] Propellant is supplied to the thrusters by pressurizing the cavities 52 above each bladder 6, 8, which forces the propellant out of the bladders 6, 8 via inner collection tubes 34 (not shown in FIG. 7). To pressurize the upper cavities 52, each cavity 52 is equipped with a pressurization inlet 54 that is fluidly connected to a pressurization system.

[0030] At least some bladders 8 are integrated with a venting system to extract (drain) unwanted fluids from the bladders 8. One example is the use of HTPs, particularly the decomposition of the liquid and the resulting increase in oxygen. To do this, a venting tube 54 may be mounted to the top 56 of the bladder 8, wrapped around the surface, and then passed through a boss to provide an exit path.

[0031] It is noted that embodiments of the bladder-based annular tank 1 that do not exhibit ring-shaped structures 2, 4 separated by a cylindrical wall 12 are also covered by the present invention.

[0032] Disclosed is an annular tank for a vehicle, the annular tank being designed as a bladder tank for storing polypropellants and as a spacecraft. [Explanation of symbols]

[0033] 1. Annular tank 2 Radial inner ring tank section (ring tank) 4 Radial outer ring tank section (ring tank) 6 Radial Inner Bladder 8 Radial Outer Bladder 10 Annular Tank Shell 12 Cylindrical Wall 14 Collection line (inner radial direction) 16 Collection line (radial outer) 22 Branch line (radial inner) 24 Branch line (radial outer) 26 Discharge pipe 28 Discharge pipe 30 Back side 32 Front 34 Collection tube 36 End face 38 End face 40 aperture 42 ports 44 Lower half 46 Inner surface area 48 dashed line 50 Upper half 52 Pressure intake port 54 Intake and exhaust pipes 56 Top of bladder 58 Flat Material Sheet X-axis direction

Claims

1. An annular tank (1) for a vehicle, comprising at least one bladder (6, 8) defining an internal fluid compartment suitable for receiving a fluid to be stored, a plurality of bladders (6, 8) are provided, each defining an individual fluid compartment; 1. The annular tank (1), wherein the bladders (6, 8) are arranged in a ring shape, each ring (2, 4) comprising a plurality of bladders (6, 8) each forming an individual fluid compartment with an individual bladder tank volume, the bladders (6, 8) being a radially inner bladder (6) and a radially outer bladder (8), the individual bladder tank volumes of the radially inner bladders (6) defining a joint radially inner tank volume and the individual bladder tank volumes of the radially outer bladders (8) defining a joint radially outer tank volume.

2. 2. The annular tank (1) according to claim 1, characterized in that a plurality of bladders forming a common tank volume are in fluid connection with a single collection line (14, 16).

3. An annular tank (1) as described in claim 2, characterized in that the collection lines (14, 16) are a first collection line (14) and a second collection line (16), and each bladder (6, 8) is equipped with a lower inner collection pipe (34) fluidly connected to the first collection line (14) or the second collection line (16).

4. Annular tank (1) according to claim 3, characterized in that the inner collecting pipe (34) extends in the circumferential direction of the annular tank (1) and opens at and between their opposite end faces (36, 38).

5. 2. The annular tank (1) according to claim 1, characterized in that the lower halves (44) of the bladders (6, 8) are fixed to their surrounding structure, while their upper halves (50) remain free.

6. Annular tank (1) according to claim 1, characterized in that each bladder (6, 8) is integrated with a pressure device adapted to support the collapse of said bladder (6, 8).

7. Annular tank (1) according to claim 1, characterized in that at least some of the bladders (8) are integrated with a suction and exhaust device adapted to exhaust gas from said bladders (8).

8. A vehicle comprising an annular tank (1) according to any one of claims 1 to 7.

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