FIXTURE ASSEMBLY

A method and apparatus for a mounting system for an elongate tank includes a pivoting fixture for retaining a first end of the tank, the fixture pivotable about an axis perpendicular to a longitudinal axis of the tank; and a translating fixture permitting axial movement of the tank in a direction parallel to the longitudinal axis of the tank.

BACKGROUND

Field

Embodiments described herein generally relate to a mounting system for an elongate tank.

SUMMARY

The present disclosure generally includes a method and apparatus for a mounting system for an elongate tank. In one embodiment, the invention includes a pivoting fixture for retaining a first end of the tank, the fixture pivotable about an axis perpendicular to a longitudinal axis of the tank and a translating fixture permitting axial movement of the tank in a direction parallel to the longitudinal axis of the tank.

DETAILED DESCRIPTION

FIG. 1is a partial side view of a trailer100for transporting tanks. An upper120and a lower130tank are shown. In one embodiment, eight tanks are arranged on the trailer in two groups of four. In one embodiment, the tanks are used for transporting compressed gas, like CNG. In one embodiment, the tanks are constructed of a flexible plastic core/liner and are then wrapped to give them an outer layer of matrix material whereby they are capable of holding gas pressurized to over 4,000 psi at room temperature. The arrangement contemplated involves filling, transporting, and emptying the tanks while they remain on the trailer100. Each tank120,130has a filling means at one end and a manifold (not shown) that permits control of the introduction and unloading of gas from a single location on the trailer.

Due to the length of the tanks, the high pressure gas therein and environmental and road conditions, the tanks must be securely mounted on the trailer. However, the mounting arrangement must also compensate for dimensional changes in the tanks brought about by pressure and temperature. Additionally, mounting must permit certain shifting of the tanks as they move due to movements and deflection of the trailer along a roadway. The tanks are equipped with a metallic, cylindrical boss at each end and each boss interacts with a fixture that secures it to the trailer but provides for certain movement of the tank within the fixture.

FIG. 2is a perspective view of a pivoting fixture200for interaction with a first end of the tank (not shown). The fixture includes an upper210and lower220pillow block with an aperture250formed therein to hold the boss of the tank. The pillow blocks are pivotally connected to a part of the trailer frame260that is in turn connected to a beam125. As will be explained herein, the first end of the tank is lowered, typically by crane, at an angle whereby the boss is cradled in the bottom pillow block220of the fixture200. The fixture is constructed and arranged to permit the pillow blocks to pivot about a pivot axis270provided by a pivot axle275. The pivoting feature permits the boss to be placed in the lower block and the upper block to be installed while an opposite end of the tank remains elevated. When the fixture is assembled, the boss is held in the aperture250created between the upper and lower pillow block members. In addition to the pivot function that permits the tank some movement when installed in the pivoting fixture, the fixture includes an anti-rotation feature in the form of an anti-rotation pin280extending into the aperture250from the lower pillow block220. A corresponding anti-rotation aperture282is formed in an outer wall of the boss as can be seen inFIG. 4. The pin280and aperture282arrangement prevent rotation of the tank along its axis but also ensure the tank is rotationally fixed in a location that permits the alignment of a number of connections that facilitate filling and emptying of the tank.

FIG. 3is a side view of the pivoting fixture and illustrates a range of motion290provided by the pivoting feature as well as the pivot axle275and the center line of pivot between the pillow blocks and a foot of the fixture. In the Figure, the fixture200is shown in its pivoted position that would be typically used as the boss of an angled tank is lowered into the fixture.FIG. 3illustrates the upper210and lower220pillow blocks assembled together but does not show the boss.

FIG. 4is a side view of the pivoting fixture200showing installation of the fixture around a boss300disposed on a first end of a tank500. Arrows specifically illustrate how the lower pillow block220can be pivoted to align the anti-rotation pin280with its mating aperture282in the boss300. Once the alignment is made and the boss300is seated in the lower pillow block220, the upper portion210can be installed and the assembly tightened.FIG. 5is a front view of the pivoting fixture200with the upper210and lower220pillow blocks assembled and the boss300of the tank500held therein. As shown, the anti-rotation pin280of the lower pillow block is installed in the mating aperture282of the boss, thereby rotationally fixing the tank500at a certain location and preventing additional rotation about the axis of the tank. The fixture200and the boss300remain free to pivot as needed about pivot axis270.

FIG. 6is a cross section side view of the boss300of the tank500installed in the pivoting fixture200. The Figure illustrates the portions of the assembly previously described, including the upper210and lower220pillow blocks, pin280and aperture282to prevent rotation as well as an interior wall315of the tank500, a reinforcement member320to which the boss300is secured, and the outer shell of the tank500. In one embodiment, the liner is formed to the inner diameter of the reinforcement member320and the tank is thereafter wrapped with carbon fiber before the boss is bolted and sealed against the liner. Flanges between the boss300and the pillow block members210,220prevent the boss from axially translating within the pivoting fixture200.

FIG. 7is a perspective view of a translating fixture400for retaining a boss (not shown) at an opposite end of the tank500. Like the pivoting fixture200, the translating fixture includes upper410and lower420pillow blocks that are connected to form an aperture450therein for retaining the boss. Unlike the pivoting fixture200, wherein axial translation is prevented by opposing flanges, the translating fixture400is intended to permit elongation and shrinkage of the tank in length as it is filled, emptied, and as the compressed gas inside reacts to environmental changes, like temperature. Additionally, the fixture400permits limited pivoting during installation for adjustments to the pivot angle of the pillow blocks in relation to the base of the fixture. As illustrated, a plurality of fasteners425are provided to prevent pivotal movement of the pillow blocks when tightened. However, the apertures426for receiving the fasteners are slot-shaped, thereby permitting some pivotal adjustment of the pillow blocks410,420about a pivot axis470. The slot-shaped apertures are utilized during installation of the tank500to compensate for a tank that for any reason is not completely straight between its two ends. In one instance the tank, due to its length and construction, sags somewhat in the center, resulting in one end being somewhat angled upwards. The adjustment feature is especially useful in these instances.

FIG. 8is a side view of the translating fixture400showing the temporary pivoting function and range of motion490available during installation of a boss in the fixture. The slot-shaped apertures permitting the pivot adjustment are visible. Also shown in the figure is a feature permitting axial translation of a boss at the second end of the tank500. The translation is facilitated by a translation bearing550that is typically formed of bronze and essentially lines the aperture450formed by the upper410and lower420pillow blocks. An annular area formed between the bearing500and the boss (not shown) is supplied with a lubricant from a lubricating source560.

FIG. 9is a side view of the translating fixture400showing installation of the fixture around a boss310disposed on a second end of the tank. The figure illustrates two typical adjustments401,403possible as a second end of the tank500with its second boss310is installed in the fixture. Arrow401illustrates the pivoting function that is possible due to the slotted apertures of the fasteners that will permit the lower pillow block420to be pivoted slightly to align with the boss310which, as previously explained might be somewhat angled and will move in a slight arc as shown by arrow402. Additionally, as shown by arrow403, the translation bearing550is adjustable along the outer surface of the boss310as needed to be housed in the annular space created between the inside surface of the pillow blocks410,420and the outer surface of the boss310.

FIG. 10is a front view of the translation fixture400with a boss310of the second end of the tank500installed therein. Visible in the Figure are the upper410and lower420pillow blocks that surround the boss310at the second end of the tank500. The translation bearing550is visible in an annular area between the pillow blocks and the boss. Additionally, the fasteners425have been tightened in their slot-shaped apertures, thereby preventing additional pivoting of the pillow blocks.FIG. 11is a side view in section showing the boss310in the translating fixture400and showing the boss310in a relatively retracted position in the fixture400. The position is illustrated by dimension D1.FIG. 12is a side view in section showing the boss in the translating fixture and showing the tank in a relatively extended position in the fixture400. The position is illustrated by dimension D2. By comparison, dimension D2inFIG. 12is substantially smaller than dimension D1inFIG. 11.

In an alternative embodiment, a wider translation bearing could be utilized to minimize the likelihood of binding between the bearing and the pillow blocks. In that instance, the entire fixture could be allowed to pivot permanently like the pivoting fixture described in relation to a first end of the tank.

In a further embodiment, the bolts attaching the translating fixture to the trailer frame could themselves be supplied with slot-shaped apertures, thereby permitting adjustment/pivoting of the fixture from side to side during installation. In another embodiment, pivoting from side to side could be accomplished by utilizing a vertically oriented axle, like axle275presently utilized for pivoting about a horizontal axis. In this manner, pivoting about a vertical axis could compensate for movement of the trailer during transportation and such a feature could be used with one or both of the fixtures200,400. Such arrangements are fully within the scope of the invention. For example,FIG. 13is a front view of a pivoting fixture that provides pivoting along a vertical as well as a horizontal axis. In addition to the features of the fixture explained in relation toFIGS. 2-6, the fixture includes a bearing and race arrangement comprising an upper race plate605, a lower race plate270, and a plurality of ball bearings610constructed and arranged to permit rotation of the assembly about a vertical axis680. The result is a fixture that permits vertical and horizontal pivot-like rotation of the fixture as needed at any time during the process of handling and transporting the tank. In an alternative arrangement, either or both of the rotational features could be locked-out if needed.FIG. 14is a top view of the fixture ofFIG. 13illustrating a range of movement690permitted by the bearing and race arrangement about center pivot point680.

As illustrated and described herein, the invention provides a novel apparatus and method for mounting and retaining elongate tanks in a manner whereby movement of the tanks due to their content, their transportation and environmental conditions can be managed and compensated for in a manner ensuring safe and efficient transportation. In one embodiment, shown inFIG. 1, the trailer holding the tanks is minimally reinforced and the tanks themselves provide strength to the trailer, thus increasing the load capacity.

In one embodiment, a tank is installed and retained as follows: A first end of an elongate tank is lowered into a saddle formed by a lower pillow block of a pivoting fixture. The fixture is pivotable about a pivot axis to facilitate receipt of a boss extending from the first end. Once a second end of the tank has been lowered, an upper pillow block is installed on the pivoting fixture and the boss is retained in an aperture formed therein. An anti-rotation pin and aperture prevent rotation of the boss and with it the tank about the tank axis. The pivoting feature retains intact after installation to compensate for movement of the tank necessitated by being transported on a roadway.

A boss at a second end of the tank is received by a translating fixture having a similarly shaped lower pillow block. The lower pillow block is initially pivotable about its own pivot axle to facilitate installation. Once the tank is installed and the upper pillow block is in place, fasteners are secured to disable the pivoting feature. However, slotted apertures receiving the fasteners permit minor adjustments to the position of the pillow blocks to compensate for a final position of the second end. After installation, a translation bearing housed between an aperture formed by the pillow blocks and the boss, permits the boss to translate axially within the fixture to compensate for retraction and lengthening of the tank while being filled, emptied or while being transported.

In one embodiment, eight tanks are installed on a single trailer, each having its own pivoting and translating fixtures. Once installed, each tank is filed with, in one embodiment compressed natural gas via a manifold. After transportation, the tanks are unloaded using the same manifold without ever being physically unloaded or removed from their corresponding fixtures.