BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a subsea vessel. More particularly, the present invention relates to subsea pressure vessel for withstanding external pressure and protecting against other environmental factors from a subsea environment.
2. Related Art
This section provides background information related to the present disclosure which is not necessarily prior art.
Pressure vessels are containers used for a number of applications to maintain an interior pressure different than that of ambient. Depending on what a pressure vessel is storing and the ambient environment it will be exposed to, pressure vessels are manufactured in a variety of structures and designs. Pressure vessels can be broadly categorized as interior or exterior. Interior pressure vessels are commonly used for storing gases or liquids at a pressure significantly higher than ambient. For example, common interior pressure vessels include certain residential hot water heaters, air brakes, natural gas storage, fire extinguishers, and scuba cylinders, etc. Exterior pressure vessels, on the other hand, contain an internal pressure that is significantly less than that of the environment. One common application for an exterior pressure vessel is deployed in a subsea environment. For example, many exterior pressure vessels are used for underwater applications such as instrumentation housings, junction box housings, camera housings, etc. Unlike interior pressure vessels, exterior pressure vessels must be structured to absorb external pressure, which increases as the pressure vessel is lowed deeper and deeper underwater. In addition, exterior pressure vessels, particularly those used in salt water, must be able to withstand extremely corrosive environments. As such, corrosion susceptible material cannot be used long-term as the integrity of the external pressure vessel will start to deteriorate via corrosion. Unfortunately, many of the most common and inexpensive materials that are strong enough to withstand large external loads are also highly susceptible to corrosion. For short term use, external pressure vessels formed of aluminum with a surface that has been anodized have been somewhat successful for short term use. However, the anodized surface has porosity and can easily be scratched, forming a spot that is vulnerable to being weakened by corrosion. For long term exposure, traditional methodologies have generally required using less common, more expensive high-strength and corrosion resistant materials.
Accordingly, there is a continuing desire to develop a pressure vessel and method of assembling same that is relatively simple in construction and exhibits the benefits of being formed of high strength materials without requiring large amounts of expensive materials.
SUMMARY OF THE INVENTION
This section provides a general summary of the disclosure and should not be interpreted as a complete and comprehensive listing of all the objects, aspects, features and advantages associated with the present disclosure.
The subject invention provides a subsea vessel comprising at least one wall having an exterior surface and an interior surface. The at least one wall forms an interior cavity that is defined by the interior surface, and the at least one wall further defines at least one opening for providing access to the interior cavity. The at least one wall includes an outer layer defining the exterior surface and an inner layer defining the interior surface, wherein the outer layer comprises a first material that is corrosion resistant and the inner layer comprises a second material that has a greater strength-to-weight ratio than that of the first material. A cap is included for sealing the at least one opening from a subsea environment when the subsea vessel is immersed in the subsea environment. The cap is removably attached to a portion of the at least one wall forming the at least one opening and includes a surface that, when in use, abuts the inner layer for withstanding a load resulting from external pressure from the subsea environment.
The subject invention further provides a method of constructing a subsea vessel comprising forming an inner layer having an interior surface and an outer surface about an interior cavity defined by the interior surface. The method proceeds by forming at least one opening with the inner layer, the at least one opening providing access to the interior cavity and providing a bearing surface around the at least one opening. The bearing surface resides between the interior surface and the outer surface. The next step involves covering the outer surface of the inner layer with an outer layer, wherein the outer layer comprises a first material that is corrosion resistant and the inner layer comprises a second material that has a greater strength-to-weight ratio than that of the first material. The method further includes providing a cap for sealing the at least one opening from a subsea environment when the subsea vessel is immersed in the subsea environment. The cap is removably attached to a portion of the subsea vessel and includes a surface that when in use abuts the bearing surface for withstanding a load resulting from external pressure from the subsea environment.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purpose of illustration only and are not intended to limit the scope of the present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings described herein are for illustrative purposes only of selected embodiments and are not intended to limit the scope of the present disclosure. The inventive concepts associated with the present disclosure will be more readily understood by reference to the following description in combination with the accompanying drawings wherein:
FIG. 1 is a perspective view of a first embodiment of a subsea vessel having a cylindrical body;
FIG. 2 is a perspective view of a first embodiment of a cap that seals the subsea vessel from an external environment;
FIG. 3 is a perspective view of a second embodiment the subsea vessel having a threaded cap;
FIG. 4 is a perspective view of a third embodiment of the subsea vessel having a first cap and a second cap;
FIGS. 5A through 5C are a series of cross-sectional views of additional example embodiments of the cap;
FIGS. 6A through 6C are a series of perspective views of additional example embodiments of the subsea vessel; and
FIG. 7 is a method flow chart including a number of steps in constructing a subsea vessel in accordance with the subject disclosure.
DESCRIPTION OF THE ENABLING EMBODIMENT
Example embodiments will now be described more fully with reference to the accompanying drawings. In general, the subject embodiments are directed to a subsea vessel having an inner layer formed of high-strength material and an outer layer that covers the inner layer and is formed of non-corrosive material. However, the example embodiments are only provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
Referring to the Figures, wherein like numerals indicate corresponding parts throughout the views, the subsea vessel having a pair of cooperating layers and method of constructing same is intended to simplify construction and expense of traditional pressure vessels while also providing easy and repeated access to an interior cavity.
As illustrated in FIG. 1, a subsea vessel 20 includes a wall 22 formed of an inner layer 24 and an outer layer 26. As will be described in greater detail below, the outer layer 26 comprises material that is non-corrosive and the inner layer 24 comprises material that has a greater strength-to-weight ratio than that of the first material. The outer layer 26 covers the inner layer 24 such that when the subsea vessel 20 is submerged in salt water or any other corrosive environment, the outer layer 26 protects the inner layer 24 from corrosion and the inner layer 24 provides structural integrity to the subsea vessel to withstand a load resulting from external pressure. The wall 22 includes an interior surface 28 and an exterior surface 30, and the interior surface 28 forms an internal cavity 32 used as storage space. The wall 22 further defines an opening 34 extending through the inner layer 24, the outer layer 26, and into the cavity 32 to provide access to the storage space.
According to the example embodiment in FIG. 1, the subsea vessel 20 has a cylindrical-shape extending between a first end 36 and a second end 38. However, in other embodiments, the subsea vessel 20 can take other shapes, for example, a cylindrical, spherical, rectangular, ovular, elliptical, etc. In the present embodiment having the cylindrical shape, the inner layer 24 forms an inner cylinder 40 and the outer layer 26 forms an outer cylinder 42. The outer cylinder 42 extends between the first end 36 and the second end 38 and the inner cylinder 40 is inset such that it extends between, but can be spaced from the first end 36 and second end 38. While the first end 36 will generally define the opening 34, the second end 38 may define a second opening 44 similar to that of the first 34. However, in an alternate embodiment, the second end 38 may be permanently enclosed. As best illustrated in FIG. 2, the inner layer 24 forming the outer cylinder 42 may have an interior diameter that is larger near the first end 36 and/or the second end 38 to facilitate the initial insertion of the inner cylinder 40. Similarly, the inner cylinder 40 may have an outer diameter that is smaller near the first end 36 and/or the second end 38 to further facilitate the initial insertion. In other words, in such arrangements, the inner cylinder 40 may be pressed into the outer cylinder 42, until it is located within the interior diameter between the first end 36 and the second end 38. In such arrangements, the inner diameter of the outer layer 26 may be slightly smaller than the outer diameter of the inner layer 24 so that the outer cylinder 42 is stretched outwardly and compresses inwardly after insertion of the inner cylinder 40.
The opening 34 may be closed via a cap 46 partially shown in FIG. 2, which is removeably attachable thereto to impermeably seal the cavity 32 from external factors like pressure. The cap 46 includes an interface surface 48 that, when in use, is pressed into some portion or bearing surface of the inner layer 24. In other words, the cap 46 and opening 34 are formed in such a way that external pressure acting inwardly is withstood via contact between the inner layer 24, that comprises high-strength material, and the cap 46. Accordingly, it is preferable that the cap 46 at least partially also comprises high-strength material that may be similar or the same as the inner layer 24 such that it doesn't break upon introduction of high external pressure. In one embodiment, the cap 46 includes an interior lining 50 of high strength material that is preferably shaped like the opening 34 but sized larger such that it forms the interface surface 48 that abuts the inner layer 24 bearing surface. In embodiments when the interior lining 50 comprises the same material as the inner layer 24, the interior lining 50 and inner layer 24 may have a similar to identical thickness. Furthermore, while the interior lining 50 is shown as being flat, it could be any shape, including semi-spherical or hemi-spherical. As such, the layer of high-strength material could be capsule-shaped for improved pressure resistance but the non-corrosive exterior may be cylindrical-shaped for improved handling and storage when not in use. In addition, it is preferable that the cap 46 further includes an exterior portion 52 that comprises non-corrosive material. At least one seal 54 is located between the exterior portion 52 and the interior lining 50. The seal 54 could be an annular ring of elastomer material. In use, the cap 46 is placed within the opening 34 and the interior lining 50 contacts the inner layer 24, the exterior portion 52 while the seal 54 prevents water from coming into contact with the interior lining 50 and entering the cavity 32. While the cap 46 may be sized in such a way that it can be press-fit into the opening 34, it is preferably that it is connected to the wall 22 by additional mechanisms. For example, the cap 46 illustrated in FIG. 2 is shown to include a flange 56 that extends radially outward and at least partially aligns with the outer layer 26. The flange 56 and outer layer 26 may both further have cooperating threaded apertures 58 that can be drawn together with fasteners 60. As such, the fasteners 60 keep the cap 46 secured tightly against the inner layer 24 until use wherein exterior pressure acting inwardly also prevents separation.
FIG. 3 illustrates a cap 62 in accordance with another embodiment of the subject disclosure. The cap 62 includes a threaded body 64 that threads directly into corresponding threads of the inner surface 24. The threaded body 64 may comprise a high-strength material, which may be similar or identical to that of the inner layer 24. Like the previous embodiment, it is preferable that the cap 62 further includes a non-corrosive portion that prevents water from contacting the high-strength material.
FIG. 4 illustrates a pair of caps 66, 68 in accordance with yet another embodiment of the subject disclosure. More particularly, the pair of caps 66, 68 includes a first cap 66 and a second cap 68, the first cap 66 having a first flange 70 and the second cap having a second flange 72. A plurality of long fasteners 74 extend through the first flange 70 and the second flange 72 and draw the caps 66, 68 towards the respective openings 34, 44. The afore described fasteners could comprise high-strength non-corrosive material such as Titanium.
FIGS. 5A through 5C are a series of cross-sectional views of additional example embodiments of the cap. Referring first to FIG. 5A, the cap 76 includes a lining 78 of high-strength material wherein the other portion of the cap is non-corrosive material. FIG. 5B is another embodiment of the cap 80 having a larger portion 82 formed of high-strength material and a relocated seal 54 to prevent water from contacting the high-strength material. While not limited thereto, the embodiment illustrated in FIG. 5B could preferably include a treaded body as previously described in reference to FIG. 3 or other suitable closure methods. FIG. 5C illustrates yet another embodiment of the cap 84 that includes a liner 86 of high-strength material that is at least partially spherical and preferably hemi-spherical for improved pressure resistance but also has an otherwise flat exterior for improved handling and storage. It should be appreciated, however, that the cap is not limited to the above noted designs and materials. For example, the cap could completely be constructed of the above noted high-strength, non-corrosive but expensive material. In addition, the cap could have a different locations and arrangements of seals 54, take various shapes to mate with openings having different profiles. In addition, the cap can have a means to penetrate (FIG. 3) to allow for mounting an electrical, fiber-optic, or connection devices. In addition, in some embodiments, the cap may be permanently affixed to the subsea vessel.
FIGS. 6A through 6C are a series of perspective views of additional example embodiments of the subsea vessel. Starting with FIG. 6A, the subsea vessel 88 is illustrated as being spherically-shaped. In FIG. 6B, the subsea vessel 90 is shown as a capsule-shape. In FIG. 6C the subsea vessel 92 has a cubic-shape with tapered edges. It should be appreciated, however, that the subsea vessel could take many more shapes than the above illustrated embodiments.
The subject disclosure further provides a method 200 of constructing a subsea vessel as illustrated in the flow chart in FIG. 7. Unless otherwise stated, none of the steps of construction are limited to any of the above example embodiments. The method 200 includes forming 202 an inner layer having an interior surface and an outer surface about an interior cavity defined by the interior surface. Next, the method 200 includes forming 204 at least one opening with the inner layer. The at least one opening provides access to the interior cavity and the inner layer further includes a bearing surface around the at least one opening. The bearing surface resides between the interior surface and the outer surface. The method 200 continues by covering 206 the outer surface of the inner layer with an outer layer, wherein the outer layer comprises a first material that is corrosion resistant and the inner layer comprises a second material that has a greater strength-to-weight ratio than that of the first material. Next, the method 200 includes providing 208 a cap for sealing the at least one opening from a subsea environment when the subsea vessel is immersed in the subsea environment, the cap being removably attached to a portion of the subsea vessel and including a surface that, when in use, abuts the bearing surface for withstanding a load resulting from external pressure from the subsea environment.
The step of covering 206 the outer surface of the inner layer with the out layer can include molding 210 the outer layer over the inner layer. While not limited thereto, the molding 210 may include one or more of compression, extrusion, injection, and blow molding. Covering 206 the outer layer over the inner layer may also include welding 212 the outer layer to the inner layer via any number of welding techniques including, but not limited to, inert gas, solid state, resistance, vibrational, etc. In addition, the covering 206 step may also include coating 214 the outer layer over the inner layer and allowing it to cure. In embodiments similar to that shown in FIGS. 1 and 2, the step of covering 206 may further yet include a step of inserting 216 an inner layer into an outer layer, wherein the inner and outer layers may be cylindrically-shaped. The covering 206 step may also include applying 218 adhesive on the inner layer and/or outer layer, contacting the inner layer and outer layer, and allowing the adhesive to cure. Note that each of the steps of covering 206 the inner layer with the outer layer may further be applied to the cap, wherein the cap includes a portion of high-strength material and a portion of corrosion-resistant material.
Unless otherwise stated, the inner layer 24 and outer layer 26 are not limited to any one materials or material combinations. However, in a preferred embodiment, the outer layer 26 is formed of a non-corrosive material and the inner layer is formed of a high-strength material. The high-strength material could include one or more of Aluminum, Ceramic, Titanium, Copper-Beryllium, High-Strength Steel, Ceramic, Nickel Alloy, or additional metal alloys. If Aluminum is used, it may have an anodized surface before covering it with an outer layer. The non-corrosive material, on the other hand, could include one or more of Titanium, polyvinyl chloride (PVC), polyethylene (PE), polyurethane, epoxy with or without glass fibers or additional dielectric materials.
It should be appreciated that the foregoing description of the embodiments has been provided for purposes of illustration. In other words, the subject disclosure it is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varies in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of disclosure.
Patent Application
20190322448
