Patent Application
20060021987
The present invention generally relates to pressure vessels, and more particularly relates to flat conformal pressure vessels.
Historically, pressure vessels for applications such as spacecraft propellant tanks have been generally configured as spheres or deviations of spheres. This type of configuration has generally been considered optimal for high-pressure tank applications since the spherical shape tends to equalize the internal pressures against the tank enclosure. A spherical configuration can also provide a relatively lightweight and compact package for vessels containing liquids or gases under pressure.
One disadvantage of a spherical type of vessel configuration is that it may result in wasted areas of space around the vessel within a typical non-spherical support structure. For applications where space is at a premium, such as in a spacecraft, a spherical tank mounted in a non-spherical support structure may not utilize the available space as efficiently as a different type of tank configuration that conforms more closely to the shape of the available space. The spherical shape may also result in a relatively high center of gravity of the vessel and associated support structure and thereby increase the load on the support structure. Moreover, any wasted volume in a spacecraft or similar application might otherwise be used advantageously, for example by enlarging a revenue-generating payload.
Accordingly, it is desirable to provide a general packaging configuration for pressure vessels that optimizes space utilization. In addition, it is desirable to provide a general packaging configuration with a relatively low center of gravity. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.
According to various exemplary embodiments, a general packaging configuration for pressure vessels is provided to optimize space utilization. One exemplary embodiment comprises a first member configured as a flat planar structure and a second member configured similarly to the first member. The second member is typically oriented parallel to the first member and is separated from the first member to form an internal space between the first and second members. In this embodiment, one or more tension members are disposed within the internal space and are connected between the first member and the second member. A hemispherical edge closure is typically configured to connect the edges of the first member to corresponding edges of the second member, thereby creating an enclosed vessel for containing a fluid under pressure. The shape of the first and second members can be optimally configured to conform to an available space.
The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.
Various embodiments of the present invention pertain to the area of pressure vessels such as propellant tanks for spacecraft applications. Traditionally, the configuration selected for this type of pressure vessel has been generally spherical, since a spherical shape has usually been considered optimal for containing liquids and gases under very high pressure (e.g., in an approximate range of about two hundred (200) to eight hundred (800) pounds per square inch (psi)). However, a spherical vessel configuration may not be an optimal fit for a typically non-spherical support structure, thus wasting a volume of space that could otherwise be utilized advantageously. Therefore, to improve the space utilization of a pressure vessel, a more versatile vessel configuration is proposed herein that can be conformed to the general shape of an available space.
In
To reduce the amount of wasted volume between a pressure vessel and the surrounding support structure, a flat conformal pressure vessel can be configured in accordance with the available space. For example, an exemplary embodiment of a flat conformal pressure vessel 202 is shown within a generally rectangular support structure 204 in
A flat conformal pressure vessel can be fabricated in various shapes, in order to optimize the configuration match between a pressure vessel and an available space. For example, as illustrated in
In order for a flat conformal pressure vessel to accommodate a range of internal liquid or gas pressures equivalent to that generally contained in a spherical pressure vessel, the flat conformal pressure vessel is typically configured with internal tension members. These internal tension members are typically connected between the flat surfaces of a pressure vessel to distribute the fluid pressure within the vessel as equitably as possible. Exemplary embodiments of internal tension member configurations are shown diagrammatically as 304, 404, 504 in
Exemplary embodiments of internal tension members 304, 404, 504 are typically configured as closely spaced thin walls oriented at an appropriate angle for optimal fluid channeling. For example, one embodiment can be configured with 0.002 inch walls spaced 0.25 inch apart, and angled at 45 degrees from the centerline of a pressure vessel, as depicted in the triangular and square shape embodiments of
Referring again to
Typically, the fluid and vent tubes (306, 308, respectively), the support fittings 310, and the internal tension members 304 are fabricated from the same material as the skin of the pressure vessel (302) in order to minimize the possibility of adverse chemical reactions between dissimilar materials, and also to simplify the manufacturing process. While a metal such as titanium has generally been found to exhibit the desired characteristics for this type of application, other materials or combinations of materials may also be considered if they meet the needs of a particular application.
In the exemplary embodiment of
While the exemplary embodiments described herein refer to pressure vessels for spacecraft applications, the disclosed flat conformal packaging concept can also be adapted to other types of pressure vessel applications in confined and/or irregularly shaped spaces, as may be found in the aircraft and automotive industries, among others.
Accordingly, the shortcomings of the prior art have been overcome by providing an improved configuration for pressure vessels such as propellant tanks used in spacecraft applications. A versatile-shape flat conformal pressure vessel configuration is disclosed that can provide a more efficient utilization of packaging space than the more traditional spherical configurations. The flat conformal configuration typically incorporates internal tension members and hemispherical edge closures to enhance the internal pressure capabilities of the vessel. The shape versatility of the disclosed embodiments can result in a lower center of gravity for a flat conformal pressure vessel and associated support structure as compared to the center of gravity of a typical spherical vessel support structure, thereby reducing the relative loading of the conformal vessel support structure.
While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof.
