The present disclosure relates to tank trailers used to transport fluids, such as liquefied petroleum gas.
In accordance with an illustrative embodiment, a tank trailer includes a container having a composite, substantially tubular body and a polar boss coupled to a distal portion of the substantially tubular body. The substantially tubular body includes an inner tubular portion and an outer shell, and the polar boss is positioned between the inner portion and outer shell of the substantially tubular body.
In accordance with another illustrative embodiment, a method of forming a tank trailer includes forming a container having a composite, substantially tubular body and a polar boss coupled to a distal portion of the substantially tubular body, and coupling a cover plate to the polar boss of the container.
The accompanying drawings, which are included to provide a further understanding of the disclosure, are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the detailed description serve to explain the principles of the disclosure. No attempt is made to show structural details of the disclosure in more detail than may be necessary for a fundamental understanding of the disclosure and the various ways in which it may be practiced. In the drawings:
The present disclosure is further described in the detailed description that follows.
The disclosure and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments and examples that are described and/or illustrated in the accompanying drawings and detailed in the following description. It should be noted that the features illustrated in the drawings are not necessarily drawn to scale, and features of one embodiment may be employed with other embodiments as the skilled artisan would recognize, even if not explicitly stated herein. Descriptions of well-known components and processing techniques may be omitted so as to not unnecessarily obscure the embodiments of the disclosure. The examples used herein are intended merely to facilitate an understanding of ways in which the disclosure may be practiced and to further enable those of skill in the art to practice the embodiments of the disclosure. Accordingly, the examples and embodiments herein should not be construed as limiting the scope of the disclosure. Moreover, it is noted that like reference numerals represent similar parts throughout the several views of the drawings.
Liquefied petroleum gas (LPG) transports typically include tank trailers having a cylindrical steel tank with hemispherical ends. Such tanks typically are completed using an upper coupler kingpin and back axle assemblies. A pump and/or valve ports for LPG product filling and emptying are typically located on the underside of the tank near the center of the length of the tank, just aft the landing gear of the trailer.
In many areas of the United States and Canada, the total weight of the tractor, trailer, and payload is limited by regulation. For example, LPG transports in much of the US are subject to a weight limit of 80,000 lbs. The weight of the steel tank system limits the amount of LPG that can be transported, thus limiting the economic efficiency of the process of transporting LPG. The present disclosure relates to a larger and lighter weight tank that allows for more LPG to be transported while remaining under the applicable weight limit, which can also withstand an internal gas pressure up to 1,325 pound per square inches, and is applicable to tandem axle trailers (front and rear lift axles), pup trailers, and other similar types of transports.
Turning now to
The pumping subsystem 112 may be a pumping and piping system located at the front portion 106 of the tank container 102. This location of the pumping system may allow more product to be removed with the tank container 102 and the tank container 102 is positioned at a slope such that product in the tank pools near to ingress point of the pumping subsystem 112. To that end, the trailer 100 may include a lifting feature, such as a hydraulic lift, to tilt the front portion 106 down relative to the rear portion 108 (or the rear portion 108 up relative to the front portion) to facilitate near complete emptying of the tank container 102 contents. In another embodiment, the orientation of the trailer 100 may be substantially reversed and the pumping subsystem 112 may be positioned at the rear portion 108 of the trailer.
The chassis 118 may generally be considered to be a frame that attaches to and supports straps 122 to secure the tank container 102 to the frame or chassis 118. The chassis 118 is connected to the suspension/wheel assembly and the kingpin assembly. In some embodiments, the chassis may be discontinuous and formed by separate frame components that do not directly couple to one another such that a portion of the tank container 102 is not directly vertically unsupported (by the chassis). In such am embodiment, the chassis 118 may include a front portion that couples the trailer 100 to the tractor 116 and a rear portion that couples to the rear axle assembly 120, with the composite tank functioning as both a container and a connection structure between the front and rear portion of the chassis 118. The straps 122 may be fastened about the tank container 102 using a variable tensioning device (e.g., a spring) to account for expansion and contraction of the tank container 102 while still providing adequate force to fasten the tank container 102 to the chassis 118 during operation.
The portion of the pumping subsystem 112 that is positioned in front of the front portion 106 may be shielded during operation by a cover 114 or fairing. In addition, the tubular member 104, front portion 106, or rear portion 108 may include a translucent portion 105, or window, having a visual indicator 107 to indicate the fill level of the container 102.
As described in more detail below, the container 102 is generally formed from a composite material, such as a carbon fiber reinforced or fiber glass reinforced polymer composite material. The composite material may be, for example, a bi-layer structure formed from an inner glass fiber reinforced vinyl ester composite overwrapped with a glass or carbon fiber reinforced epoxy composite. The epoxy composite is preferably an epoxy composite fabricated with an epoxy resin that cures without the use of oven or autoclave, and that can still produce high-glass transition temperature. The epoxy composite may be a high-performance composite similar to a composite that is cured with a conventional high-temperature oven or autoclave-cured composite. The epoxy resin in the epoxy composite may be cured by a self-generated heat from an exothermic reaction of the resin. Examples of such epoxy composites and epoxy resins include those made by NONA Composites of Dayton Ohio, including without limitation NONA R102/H11 and R404/H18 Infusion Epoxy Resins. Other examples include Diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, resorcinol diglycidyl ether, N,N-Diglycidyl-4-glycidyloxyaniline, brominated diglycidyl ether of bisphenol A, novolac epoxy, tetraglycidyl meta-xylenediamine, 1,4-butanediol diglycidyl ether, 4,4′-Methylenebis(N,N-diglycidylaniline), tris(4-hydroxyphenyl)methane triglycidyl ether, tris(2,3-epoxypropyl)isocyanurate, and combinations thereof; and epoxy curing agents.
In an illustrative embodiment, as shown in
An angled, flange portion 228 of the front polar boss 220 is bonded between a portion of the inner tubular portion 222 and an outer shell 224 of the front portion 206. The inner tubular portion 222 is generally formed from (for example) an inner glass fiber reinforced vinyl ester composite, while the outer shell 224 is generally formed (for example) from a carbon fiber reinforced epoxy composite. Other exemplary materials include metal, such as an aluminum or steel, overwrapped with a fiber reinforced polymer composite. The front polar boss 220, which may generally be formed from steel, such as stainless steel, carbon steel, or a CorTen (R) steel, is coupled to a front plate 226 which, as described below, provides an interface to a pumping subsystem. A vinyl ester resin may be used to bond the inner tubular portion 222 to the front polar boss 220.
As shown in more detail in
An illustrative embodiment of a polar boss 300, analogous to the polar bosses referenced with regard to
When assembled, the polar boss 300 may be generally understood to be an integrated polar boss, which is metallic ring shaped component that is partially enclosed between an inner tubular portion and the outer shell of the tubular member. In an illustrative embodiment, the boss is configured to be a structure that functions as a mounting interface for additional components, such as a cover plate.
The tank 400 generally comprises a fiberglass composite construction with the front polar boss 416 and rear polar boss 418 being constructed from steel. The tank segments 402, 403 may similarly be fabricated from glass fiber reinforced polymer composite or polymer composite made with a combination of glass and carbon fiber reinforcement. The polar bosses 418, 418 may be constructed from the same or similar materials, in addition to or instead of steel.
In some embodiments, the tank 400 includes a an inner tubular portion that serves as a pre-cured inner leave-in mandrel that is tubular member fabricated by conventional polymer composite layup processes from multiple individual fiberglass reinforced polymer composite components that are bonded together. The tank includes the first polar cap 404 and second polar cap 406, each of which is joined to the cylindrical portion of the tubular member assembly. Each of the polar bosses 416, 418 is bonded to the outside of the inner tubular portion. In an embodiment, the polar bosses 416, 418 and inner tubular portion are overwrapped with fiber saturated with liquid resin using a filament winding process. The entire assembly is then heat cured to become a single piece solid composite tank. This process creates an outer composite shell that serves as the main structure of the tank 400. The outer layer bonds to the inner tubular portion during the fabrication process, effectively creating a one piece solid composite tank. In an illustrative embodiment, the inner tubular portion material is a fiberglass and vinyl ester resin based composite material and the outer layer is a fiberglass and epoxy resin based composite material.
It is noted that vinyl ester and epoxy resins may be used on either layer depending on the tank lading and the required compatibility with the lading material. In an alternative embodiment, the tank 400 may have a thermoplastic liner for material containment, which is overwrapped with fiber saturated with resin to create a structural shell.
In an illustrative manufacturing process, fabrication of the tank 400 includes fabricating the inner composite tubular components, such as the barrel segments 402, 403, first polar cap 404, and second polar cap 406 using a fiberglass or vinyl ester. The polar bosses 416, 418 may then be bonded to the first polar cap 404 and second polar cap 406, respectively, with vinyl ester or another suitable bonding material. The container may then be completed by using a filament wind process to form an outer layer that encases a portion of the polar bosses 416, 418, the first polar cap 404, second polar cap 406, and barrel segments 402, 403. The winding process may be completed using NONA R404/H18 epoxy or any other suitable material. The filament winding process involves winding tensioned filaments over the rotating inner tubular barrel. The winding filaments are impregnated with resin by passing the filaments through a resin bath as they are wound about a tool die. The tubular barrel rotates around a spindle while a delivery eye on a carriage traverses horizontally in line with the axis of rotation of the tubular barrel, laying down fibers in the desired pattern or angle on the tubular barrel. Once the tubular barrel is completely covered to the desired thickness, the part can be cured to produce the composite tank. Following the winding process and curing, the tank 400 may be painted to complete the tank assembly.
Referring again to
Typical LPG transport trailers include pump and piping features for LPG lading filling and emptying. Such pumping operations are typically located on the bottom of the tank in between the kingpin and the rear suspension system—near the midpoint of the trailer tank. In accordance with an illustrative embodiment of the present disclosure, however, a pumping subsystem is instead coupled to the front cover plate 412 affixed to the front polar boss 416.
An exemplary configuration of such a pumping subsystem is described in more detail with regard to
In the embodiment of
The illustrated positioning of the pumping subsystem 504 at the end of the tank container 502 provides a number of advantages. For example, a tank trailer 500 having a composite tank container 502 with penetrations only in the polar boss regions and a polar boss mounted pumping and piping system allows for a larger payload in addition to the ability to remove more of the LPG lading from the tank during emptying operations. The tank container 502 is lighter weight because the composite structure does not need additional structural support to reinforce weakened areas formed by penetrations in the composite material. Further, the illustrative system may remove more of the LPG lading since the tank can be slightly tipped towards the pumping system and allow more liquid to collect near the pump piping and be pumped out of the tank, as opposed to draining towards a pump near the bottom center along the length of a similar tank. In addition, the pump location at the polar boss results in the pump being less likely to ingest foreign matter from the LPG lading because the LPG is pulled up and not pulled down during the unloading pumping process (as a result of the liquid lines 514, 516 angling downward to the base of the tank container 502 to remove the LPG lading from the tank). In some embodiments, the tank container 502 may be biased or formed such that the liquid lines 514, 516 terminate at the lowest point in the tank container 502 when the tank container 502 is parked on a flat surface to facilitate unloading of the tank container 502.
As shown in the schematic of
This application claims the benefit of and priority to U.S. Provisional Application No. 62/363,055, filed Jul. 15, 2016, which is hereby incorporated by reference.
Number | Date | Country | |
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62363055 | Jul 2016 | US |