The instant disclosure relates to the transport of cryogenic materials. More specifically, portions of this disclosure relate to trailer designs for the transportation of cryogenic materials.
Cryogenic liquids may be stored and transported at low temperatures. For example, some cryogenic liquids may have boiling points below −130 degrees Fahrenheit and may be stored at low temperatures to maintain liquid form. One example of a cryogenic liquid, liquid Oxygen, may be transported at temperatures below −300 degrees Fahrenheit, the approximate boiling point of liquid Oxygen. As another example, liquid Argon likewise has a boiling point of approximately −300 degrees Fahrenheit and may be similarly maintained at low temperatures during transport. Other examples of cryogenic liquids may include liquid Nitrogen and liquid Helium. Environmental temperatures on Earth are far greater than the boiling points of cryogenic liquids, and thus transport structures must provide sufficient isolation between a storage unit for the cryogenic liquid and the environment during transport. Failure of the isolation structure may result in significant pressure build-up in the storage unit due to gasification of the cryogenic liquid, and possibly an explosion. Strong support structures for cryogenic transport structures may reduce the possibility of a dangerous explosion. However, the cryogenic transport structures must also meet guidelines that restrict the weight of trailers towing the cryogenic transport structure due to weight limits of road structures, such as bridges.
A cryogenic transport structure, such as a dewar, mounted on a trailer and towed by a tractor, may be made of light-weight materials such as aluminum when accompanied by appropriate support structures that provide strength and resiliency to the cryogenic transport structure to sufficiently reduce the likelihood of dangerous explosions resulting from regasification of the cryogenic liquids during transport. For example, a weight of the trailer and transport structure may be reduced substantially by constructing all or part of the transport structure and/or trailer from aluminum when the tank is securely mounted to prevent failure of the transport structure. The weight limit of bridges and roads includes the weight of the structure and the weight of the cryogenic liquid. Thus, reducing the weight of the structure allows larger amounts of cryogenic liquid to be transported while remaining under the bridge weight limits. This reduces the cost of transporting the cryogenic liquid on a per-unit basis by allowing more cryogenic liquid to be carried in a tank.
An aluminum-based cryogenic dewar may include an outer tank and an inner tank. The inner tank may be coupled to and mounted within the outer tank using a plurality of trunnion mounts, allowing for a degree of resiliency in the mounting to dampen complex radial and axial forces generated by movement of the inner tank with respect to the outer tank. The use of a series of aligned trunnion mounts to couple the inner tank to the outer tank and/or internal longitudinal support stiffeners may enable more efficient dampening of movements of the outer tank, for example due to movement of a trailer on which the outer tank is located, and the inner tank and may strengthen a structural integrity of the inner tank. The secure and stable mounting provided by the trunnion mounts and the enhanced structural integrity of the inner tank provided by the internal longitudinal support stiffeners, may allow for lightweight materials, such as aluminum, to be used to form the structure of the dewar and the trailer while maintaining and/or improving a strength of the dewar.
In some embodiments, eight trunnion mounts may be used to couple the inner tank to the outer tank. A first four of the eight trunnion mounts may be coupled between a front half of the inner tank and a front half of the outer tank, and the other four of the eight trunnion mounts may be coupled between a rear half of the inner tank and a rear half of the outer tank. For example, a first trunnion mount of the first four trunnion mounts and a first trunnion mount of the second four trunnion mounts may be coupled between a top of the inner tank and a top of the outer tank. A second trunnion mount of the first four trunnion mounts and a second trunnion mount of the second four trunnion mounts may be coupled between a bottom of the inner tank and a bottom of the outer tank. A third trunnion mount of the first four trunnion mounts and a third trunnion mount of the second four trunnion mounts may be coupled between a road side of the inner tank and a road side of the outer tank. The road side of the inner tank and the outer tank may, for example, be a left-hand side of the inner and outer tanks when viewed from a cab pulling a trailer supporting the dewar. A fourth trunnion mount of the first four trunnion mounts and a fourth trunnion mount of the second four trunnion mounts may be coupled between a curb side of the inner tank and a curb side of the outer tank. The curb side of the inner tank and the outer tank may, for example, be a right-hand side of the inner and outer tanks when viewed from a cab pulling a trailer supporting the dewar. Thus, trunnion mounts may be positioned directly across from each other at the top and bottom of the dewar and on the right and left of the dewar, at the front and the back of the dewar, to provide support for the inner tank housing the cryogenic liquid. In some embodiments, more than or fewer than eight trunnion mounts may be used to support the inner tank within the outer tank of the cryogenic dewar.
The inner and outer tanks of the cryogenic dewar may be aluminum tanks. In some embodiments, a trailer upon which the dewar is mounted may also be formed from aluminum. The trunnion mounts may provide sufficient support for inner tank within the outer tank, allowing for safe transport of cryogenic liquids while reducing an empty weight of the dewar and/or the trailer due to the use of aluminum. Use of aluminum in the structure of the dewar and/or the trailer may also reduce the susceptibility of the trailer and/or dewar to corrosion, due to the corrosion-resistant properties of aluminum.
The trunnion mounts may comprise aluminum tubing. For example, the trunnion mounts may each comprise segments of eight inch outside diameter aluminum tubing, such as 5086 aluminum tubing, extending from an outer surface of the inner tank to an outer surface of the outer tank. The eight inch or larger diameter provide additional area and/or reinforcement to reduce likelihood of failure of the dewar. For example, the aluminum tubing of the trunnion mounts may extend to the outer tank, such as through windows or holes cut or otherwise formed in the outer tank. In some embodiments, the trunnion mounts may include one or more fiberglass supports between the inner tank and the outer tank to support the trunnion mounts. The fiberglass supports may insulate the inner tank from an external environment, inhibiting heat transfer from the inner tank to the outer tank and the external environment via the trunnion mounts.
In some embodiments, the trunnion mounts may include a plurality of pie-shaped reinforcing pads, such as four quarter-circle pads. Although quarter-circles are described for the pads, the pads may be other sizes of sectors of a circle or other shapes (e.g., rectangles or triangles). The reinforcing pads may be welded to each other and to an outer surface of the inner tank. For example, the pads may form a base for all or part of the trunnion mount on the external surface of the inner tank. The reinforcing pads may be curved to fit the form of the surface of the inner tank. Welding of four, or more, pie-shaped reinforcing pads in a circular arrangement may strengthen the support provided by the trunnion mounts. For example, use of four pie-shaped reinforcing pads in place of a single circular or rectangular reinforcing pad may provide additional welding surface area which may strengthen a connection between the trunnion mounts and the inner tank. In some embodiments, patch plates, such as circular patch plates may be attached to an outer surface of the outer tank adjacent the plurality of trunnion mounts. For example, a tube of the trunnion mount may extend to an opening in the outer surface of the outer tank. Patch plates may be fixed in place over such openings, such as by welding the patch plates to the outer surface of the outer tank.
In some embodiments, an insulation pad may be attached between the segment of the aluminum tubing and the inner surface of the outer tank and/or the patch plate. In some embodiments, one or more insulation pads may be coupled to an outer surface of the inner tank adjacent to the tube segment of each trunnion mount. Longitudinal support stiffeners may, in some embodiments, be coupled between a first portion of an inner surface of the inner tank adjacent a first trunnion mount and a second portion of an inner surface of the inner tank adjacent a second trunnion mount. Such longitudinal support stiffeners may further strengthen the structural integrity of the inner tank, rendering the dewar more resilient in the face of complex axial and radial forces that the inner tank, the outer tank, and the trunnion mounts may encounter during transportation of cryogenic fluids and thus less susceptible to structural failure.
In some embodiments, a length of a trailer upon which the dewar is mounted may be less than thirty-five feet. For example, an aluminum dewar and with trailer may transport a same or similar amount of cryogenic liquid as a steel dewar and with trailer in a shorter trailer frame while maintaining compliance with state and federal weight distribution guidelines, due to the high strength-to-weight ratio of aluminum. A trailer that is less than thirty-five feet in length, such as thirty-four feet or thirty-two feet in length, may provide enhanced maneuverability over a trailer that is forty to forty-two feet long. For example, shorter trailers may be easier to maneuver in urban settings, where a tighter turn radius may be desirable. Further, transportation of an aluminum dewar with trailer may be more cost effective due to the lower weight of aluminum. In some embodiments, the dewar with trailer may include a hydraulic cryogenic off-loading system built into the dewar and/or trailer further enhancing efficiency in offloading transported cryogenic liquids over systems that must be connected to external offloading systems for offloading. For example, integrated offloading systems may offload cryogenic liquids at a greater rate than external systems.
The foregoing has outlined rather broadly certain features and technical advantages of embodiments of the present invention in order that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter that form the subject of the claims of the invention. It should be appreciated by those having ordinary skill in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same or similar purposes. It should also be realized by those having ordinary skill in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. Additional features will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended to limit the present invention.
For a more complete understanding of the disclosed system and methods, reference is now made to the following descriptions taken in conjunction with the accompanying drawings.
Cryogenic dewars may be used to transport cryogenic liquids, such as Oxygen, Nitrogen, and Argon, at low temperatures. Cryogenic dewars may include a first, inner tank, mounted inside and supported by a second, outer, tank. The use of nested tanks may insulate the cryogenic liquid to help maintain low temperatures of the liquid during transport. An example illustration 100 of a cab 106 pulling a trailer 104 holding a cryogenic dewar 102 is shown in
An example cryogenic dewar 200 is shown in
Some dewars may require external offloading systems to offload cryogenic liquids once the dewar has reached its destination. A lightweight dewar, such as a dewar constructed primarily from aluminum may include an internal offloading system, or one located on the same trailer as the lightweight dewar, while transporting a similar volume of cryogenic liquids to an amount contained in a dewar made of steel and remaining within federal weight limits. Including an offloading system in the dewar 200 or on a trailer transporting the dewar 200 may enhance the efficiency and speed of offloading cryogenic liquids. A dewar 200 may include multiple valves 206A-C.
An example cross section 300 of a cryogenic dewar showing positioning of trunnion mounts 302A-D is shown in
An example trunnion mount 302C is shown in greater detail in
The trunnion mount 302C may include a tubing segment 410, such as an aluminum tubing segment to form the core of the trunnion mount 302C. The tubing segment 410 may be a segment of eight inch outside diameter tubing. The tubing segment 410 may be welded to a surface of a reinforcing pad 422. In some embodiments, a support frame 408, which may include one or more support retainers for housing fiberglass supports, may be welded in place about the tubing segment 410. The support frame may, for example, include a fiberglass support segment 406. The fiberglass support segment 406 may provide enhanced insulation to cryogenic fluid in the inner tank 306, inhibiting flow of heat from the inner tank 306 to the outer tank 304 and an external environment via the trunnion mount 302C. A support doubler 402 may be attached to the reinforcing pad 422 and may provide enhanced support to the trunnion mount 302C.
Furthermore, additional support insulation 404, such as fiberglass support insulation, may provide enhanced insulation between the inner tank 306 and the outer tank 308. A support frame weldment 416 may connect the frame to 408 to an outer support frame 420 that is welded to a surface of a cutout in the outer tank 304. The support frame weldment 416 may include one or more stainless steel bars. A patch plate 418 may be welded or otherwise attached to an outer surface of the outer tank 304 over the cutout for the trunnion mount 302C. Additional insulation patches, such as a support insulation patch 412 may be included between the tubing segment 410 and the patch plate 412 of the trunnion mount 302C.
In some embodiments, two or more of the trunnion mounts may include internal longitudinal support stiffeners to reinforce the inner tank at the trunnion attachment areas and reduce torsional forces in the inner tank. An example segment 500 of an inner tank is shown in
In some embodiments, pie-shaped reinforcing pads may be used to strengthen a connection of a trunnion mount to an exterior surface of an inner tank of a cryogenic dewar. For example, as shown in trunnion mounting location 600 of
A method 700 for assembling a dewar having multiple trunnion mounts between an inner tank and an outer tank is shown in
At step 704, a window may be cut in insulation for the trunnion. For example, insulation may be placed over part or all of the opening in the outer tank and a window may be cut in the insulation for one or more components of the trunnion mount.
At step 706, fiberglass supports may be used to position the trunnion mount within the opening in the outer tank. For example, fiberglass supports of the support frame may be used to position one or more components of the trunnion, such as a segment of aluminum tubing. The fiberglass support may, for example, be centered in the frame using one or more stainless steel bars of the support frame. The trunnion mount may then be tack welded, at step 708, to the support frame, and part or all of the fiberglass support may be removed. The fiberglass support may be removed during operation of the trunnion mount, such that space 406 is empty. In some embodiments, stainless steel strips may also be installed between fiberglass supports and retainers during welding. Retainers may also be welded in place as part of a support frame. The dimensions of the trunnion mount, such as support interface dimensions, may be confirmed after welding.
At step 710, a doubler support may be positioned at the base of the trunnion mount, either at the surface of the inner tank or at the plurality of pie-shaped reinforcing pads welded to the external surface of the inner tank. At step 710, the doubler support, and, in some embodiments, other components of the trunnion such as the segment of aluminum tubing, may be welded to each other and/or to the inner tank.
At step 712, insulation may be installed within the trunnion and/or at an outer surface of the trunnion mount. A patch plate may be welded to an outer surface of the outer tank over the trunnion mount opening to cover the trunnion mount opening. For example, the patch plate may be centered over the trunnion mount cutout in the outer tank. The insulation and fiberglass supports may provide insulation to the cryogenic fluids in the inner tank, inhibiting warming of the inner tank by transfer of heat from the cryogenic fluid to the external environment through the trunnion mounts.
The schematic flow chart diagram of
Although the present disclosure and certain representative advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the present disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
This application claims the benefit of priority of U.S. Provisional Patent Application No. 62/891,020 filed on Aug. 23, 2019 and entitled “Aluminum Micro Bulk Trailers (Mini Trailer),” which is hereby incorporated by reference herein.
Number | Date | Country | |
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62891020 | Aug 2019 | US |