Note: Descriptions are shown in the official language in which they were submitted.
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VERTICAL STORAGE VESSEL
RELATED APPLICATIONS
This application claims the benefit of U. S.
Provisional Application Serial No. 60/911,791, filed
April 13, 2007, entitled Vertical Storage Vessel, which
is hereby incorporated by reference.
TECHNICAL FIELD OF THE INVENTION
The present disclosure is related to storage vessels
and more particularly, to vertical storage vessel systems
and methods for example, for storing liquefied petroleum
gas ( "LPG" ) .
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BACKGROUND OF THE INVENTION
Storage vessels or tanks are used to store volatile
liquids and gases. For example, LPG tanks are often used
to contain liquefied petroleum gas such as propane. LPG
tanks come in a variety of sizes and are used in both
commercial and residential applications. LPG tanks are
often used in residential applications to provide fuel
for fireplaces, stoves, and dryers. LPG tanks may be
used in commercial application to provide fuel to heat a
building.
To get an LPG tank from the manufacturer to a
retailer or other user that may fill the tank and offer
it for sale, multiple LPG tanks may be transported on a
semitrailer(s) having certain dimensions governed by
federal regulations.
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SUMMARY OF THE INVENTION
The teachings of the present invention include a
storage vessel that has dimensions selected to increase
the number of vessels that can be transported on a
semitrailer. In accordance with a particular embodiment
of the present invention, a vessel for containing
liquefied petroleum gas includes a tank. The tank may
have an outside diameter that is greater than thirty
inches and less than thirty-four inches. The tank may be
configured to contain at least 119 water gallons, and may
be further configured to contain liquefied petroleum gas.
In accordance with another embodiment of the present
invention, a method for loading a semitrailer with
vessels includes providing a plurality of vessels. Each
vessel may have an outside diameter that is greater than
thirty inches and less than thirty-four inches. Each
vessel may be configured to contain at least 119 water
gallons, and may be further configured to contain
liquefied petroleum gas. At least thirteen stacks of
vessels may be loaded on a semitrailer, wherein each
stack comprises nine vessels, and wherein an imaginary
centerline of each vessel is substantially horizontal.
Technical advantages of particular embodiments of
the present invention include an LPG tank that has the
capacity to hold 119 water gallons and is sized to
increase the number of tanks that may be loaded on a
semitrailer for transport.
Further technical advantages of particular
embodiments of the present invention include a tank that
is relatively shorter and has a greater outer diameter
than a conventional LPG tank, that is still capable of
being used in conventional tank applications.
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Still further technical advantages of the present
invention include an LPG tank that is less than four feet
tall, which is the standard height for the sill of a
window in a residence. Therefore, an LPG tank in
accordance with the teachings of the present invention
may be placed on the outside of a residence near a window
and not block a view out of the window.
Still further technical advantages of the present
invention include valve and fitting placement that may
make fluid communication among multiple LPG tanks easier.
Allowing fluid communication among LPG tanks may
substantially increase the quantity of available propane
for certain applications. Still further technical
advantages of the present invention include an improved
design of an LPG tank collar and lid interface that may
improve manufacturing and assembly.
Other technical advantages will be readily apparent
to one of ordinary skill in the art from the following
figures, descriptions and claims. Moreover, while
specific advantages have been enumerated above, various
embodiments may include all, some, or none of the
enumerated advantages.
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BRIEF DESCRIPTION OF THE DRAWINGS
A more complete understanding of the present
embodiments and advantages thereof may be acquired by
referring to the following description, taken in
5 conjunction with accompanying drawings, in which like
reference numbers indicate like features, and wherein:
FIGURE 1 is a schematic drawing of an embodiment of
the present invention having an illustration of a
conventional LPG tank superimposed;
FIGURE 2A is a schematic drawing of a side view of
an LPG vessel in accordance with an embodiment of the
present invention;
FIGURE 2B is a schematic drawing of a top view of an
LPG vessel in accordance with an embodiment of the
present invention;
FIGURE 2C is a schematic drawing showing the detail
of a head to shell seam in accordance with an embodiment
of the present invention;
FIGURE 2D is a schematic drawing of an embodiment of
the present invention showing a lid and collar interface
in partially exploded view;
FIGURE 3 is an illustration of an embodiment of the
present invention showing a load layout of a semitrailer
loaded with LPG vessels in accordance with an embodiment
of the present invention;
FIGURE 4 is a schematic drawing of another
embodiment of the present invention showing a second load
layout of a semitrailer loaded with LPG vessels in
accordance with an embodiment of the present invention;
FIGURE 5 is a schematic drawing of an embodiment of
the present invention showing an end view of a
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semitrailer loaded with LPG vessels in accordance with an
embodiment of the present invention;
FIGURE 6 is a schematic drawing illustrating a
detailed view of an embodiment of the present invention
showing LPG vessels separated by protective material; and
FIGURE 7 is an illustration of a load layout of a
semitrailer loaded with 320 gallon LPG vessels in
accordance with a further embodiment of the present
invention.
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DETAILED DESCRIPTION OF THE INVENTION
The present disclosure is directed to a liquefied
petroleum gas ("LPG") tank assembly which may also be
referred to as a vessel. Dimensions of the tank assembly
may be selected to allow the tank to hold a certain
quantity of liquid or pressurized gas while still
allowing a maximum number of tanks to be transported on a
semitrailer having length and width dimensions in
compliance with United States federal size regulations
for commercial vehicles.
FIGURE 1 illustrates an improved LPG tank assembly
12 which may also be described as a vertical storage
vessel, a bottle, or a cylinder. Improved LPG tank
assembly 12 is shown in FIGURE 1 by solid lines.
Superimposed over improved LPG tank 12 is conventional
LPG tank 10, illustrated by broken lines on the drawing.
Both improved LPG tank 12 and conventional LPG tank 10
are capable of holding 119 water gallons. Improved LPG
tank 12 is shorter and wider than conventional LPG tank
10. The outer diameter of conventional LPG tank 10 (OD1)
may be 30 inches while the outer diameter of improved LPG
tank 12 (OD2) may be 33 inches. In accordance with
particular embodiments of the present invention, ODz may
be greater than 30 inches and less than or equal to 35
inches. OD2 may also be greater than 31 inches and less
than 34 inches.
Conventional LPG tank 10 includes a domed lid 14 and
a standard collar 17. Improved LPG tank 12 also achieves
reduced height for example, by replacing domed lid 14
with flat lid 16 and replacing standard collar 17 with
shorter, improved collar 18.
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By reducing the height of the collar, flattening the
lid, and increasing the outer diameter, improved LPG tank
12 may have an overall height (H2). H2 may be greater
than or equal to 44 inches and less than or equal to 55
inches. In accordance with other embodiments of the
present invention, H2 may be greater than or equal to 44
inches and less than or equal to 48 inches. In
accordance with particular embodiments of the present
invention, H2 may be equal to 44.085 inches. A reduced
height base 19 may also contribute to reduced height H2.
Improved LPG tank 12 achieves a significant reduction in
height from height H1 of conventional LPG tank 10 which
may be 55.375 inches to H2, which may be 44.085 inches,
the difference being H1 - H2 or 11.290 inches.
Consistent with the teachings of the present
invention, LPG vessels of various capacities may have
reduced length and increased outer diameter compared to
conventional tanks of the same capacity or volume. For
example, LPG vessels that are capable of containing 320
water gallons may be made to have a reduced length of 84
and 3/16ths inches and an outer diameter of 33 inches.
400 water gallon LPG vessels may also have a 33 inch
outer diameter consistent with the teachings of the
present invention.
A 119 water gallon LPG vessel in accordance with the
teaching of the present invention may have a volume or
capacity in water gallons that is greater than or equal
to 3.4 and less than or equal to 3.9 times its outer
diameter in inches. It may also have a volume in gallons
that is less than or equal to 3.8 and greater than or
equal to 3.5 times its outer diameter in inches. In
accordance with a particular embodiment of the present
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invention, a 119 water gallon LPG vessel may have a
volume or capacity (119 gallons) that is 3.6 times the
outer diameter of the vessel in inches. In addition, the
volume or capacity in water gallons (119 water gallons)
of an LPG vessel in accordance with the teachings of the
present invention may be 2.7 times its height in inches.
In accordance with a particular embodiment of the
present invention, a 320 water gallon LPG vessel may have
a volume or capacity in water gallons that is 3.8 times
its length in inches.
In accordance with particular embodiments of the
present invention, an LPG vessel may have a height in
inches that is greater than or equal to 1.33 and less
than or equal to 1.67 times its outer diameter in inches.
A particular embodiment of the present invention may have
a height in inches that is equal to 1.45 times its outer
diameter in inches.
FIGURE 2A illustrates an LPG tank assembly or vessel
in accordance with a particular embodiment of the
20 present invention. Tank assembly 20 includes base 22,
tank 32, lifting lug 26, and cover assembly 30. A
cylindrical collar 34 is fixed to the top of tank 32 and
includes two visible access openings 35. Cylindrical
collar 34 may surround valves and fittings located at the
top of tank 32. The valves and fittings allow access to
the contents of tank 32 and further allow tank 32 to be
filled.
Lid 36 includes top surface 19 that is flat and
generally perpendicular to an imaginary centerline 43 of
tank 32 when lid 36 is in its closed position. Being
flat, top surface 19 of lid 36 decreases the overall
height E of LPG tank assembly or vessel 20. By
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decreasing the overall height of LPG tank assembly 20,
more tank assemblies 20 may fit on a semitrailer as shown
in FIGURES 3 and 4. The height of cylindrical collar 32
may be selected to allow cylindrical collar 32 to
5 adequately protect the valves and fittings and also to
minimize the overall height of LPG tank assembly 20.
The outer diameter of tank 32 and LPG tank assembly
is designated in FIGURE 2A as G. LPG tank assembly 20
may be a 119 gallon LPG tank. Outer diameter G may be
10 selected such that LPG tank assembly 20 is capable of
holding 119 water gallons and also selected to allow
three tanks on their side and positioned generally
tangent to each other on a semitrailer to maximize the
surface of the semitrailer occupied by the vessels (see
15 FIGURE 5). In certain embodiments of the present
invention, outer diameter G may be equal to 33 inches and
overall height E may be equal to 44.085 inches
Tank 32 includes shell ring 42, bottom head 38 and
top head 40. Shell ring 42 may be 0.192 inches thick and
20 22 inches long (dimension C). It may also have
longitudinal seam 44 created by welding two lateral edges
of shell ring 42 together with a full weld. Shell ring
42 may be fixed to top head 40 and bottom head 38 with a
spot weld performed in accordance with UW-11(a)(5)(b)
See FIGURE 2C.
Bottom head 38 and top head 40 may each be a 2:1
elliptical head with a 0.172 inch minimum thickness in
accordance with ASME standards. Bottom head 38 and top
head 40 may also have thicknesses in accordance with U.S.
Department of Transportation standards. Bottom head 38
and top head 40 may have an outer diameter of 33 inches.
Top head 40 may be substantially similar to bottom head
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38 with the exception that top head 40 may have
prepunched holes to receive couplings that will fit
valves and other fittings of tank assembly 20. Top head
40 and bottom head 38 may have respective heights B and D
of 8.340 inches.
LPG tank assembly 20 may be composed of material in
accordance with ASME standards or may be material
specified by U.S. Department of Transportation
regulations for portable cylinders. In accordance with
ASME standards governing pressure vessels, top head 40
and bottom head 38 may be made of SA414G steel. Shell
ring 42 may be made of SA455 steel. A36 steel or
equivalent may be the material for collar 34, base 22,
and lift lug 26. The couplings welded to top head 40 may
be SA105 steel. Collar 34 may have 3 tabs to facilitate
welding to top head 40. Lid 36 may have a 16 inch outer
diameter and may be made of C.Q. G-30 galvanized carbon
steel.
Reference number 46 indicates a reference line at
the level of tank assembly 20 to which liquid would rise
when the tank is 80% full. Dimension H shows 80% liquid
level 46 being 10.1 inches below the top of coupling 48.
Cover assembly 30 may have an overall height of A, where
A equals 5.8125 inches. Base hole 50 may be aligned with
lift lug 26.
FIGURE 2B illustrates a top view of tank assembly
20. The location of the valve couplings are visible from
FIGURE 2B. Valve couplings are located on arcs I and K.
Arc I may have a radius of 3.250 inches, and arc K may
have a radius of 4.298 inches. Valve coupling 64 and
valve coupling 68 are located on arc I. Valve couplings
66 and 70 are located on arc K. This configuration
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allows valve couplings 70, 68, and 66 to be substantially
in a straight line.
Valve couplings 64, 66, 68, and 70 may be a 3000#
half coupling and may be three quarters of an inch, one
inch, or one and one quarter inches in diameter. Valve
coupling 64 may be capable of receiving a fill valve.
Valve coupling may be capable of receiving a relief
valve, and valve coupling 68 may be capable of receiving
a service valve. Coupling 70 may be capable of receiving
a float gauge.
The specific location of valve couplings 64, 66, 68,
and 70 may allow a T-block to be coupled to a service
valve secured to valve coupling 68. This T-block may
allow multiple LPG tank assemblies to be coupled to each
other through a conduit that is received by the T-block
through collar 34 at a access opening 35. This may allow
multiple tank assemblies to be coupled together while lid
36 remains in a closed position. By coupling multiple
tanks, available propane is increased to 240 gallon
capacity or more without having to install a larger
capacity tank.
Lid stop 60 may be coupled to cover assembly 30 by
cotter pin 62. Cotter pin 62 may be 4 inches long. See
FIGURE 2D for more detail. Valve couplings 64, 66, 68,
and 70 may be located at angles designated by J, L, M,
and N, where J equals 15 degrees, L equals 30 degrees, M
equals 19 degrees, and N equals 11 degrees.
FIGURE 2C illustrates a detail of the seam where top
or bottom head 38 or 40 may be welded to shell 42.
Dimension N equals approximately 13/16 inches, and
dimension 0 equals a minimum flat portion of 1 and 1/2
times the thickness of the steel. The seam shown may be
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created by in accordance with ASME standards by a spot x-
ray per UW-11 (a) (5) (b) with a weld re-enforcement inside
and outside of 1/8th of an inch. The seam may also be
created in compliance with U.S. Department of
Transportation regulations governing portable cylinders.
FIGURE 2D illustrates an isometric view of the
coupling between lid 36 and collar 34. Two collar tabs
82 each may have an aperture to receive cotter pin 62.
Two corresponding lid tabs 86 each may also include an
aperture 84 to receive cotter pin 62.
Collar tabs 82 may be formed by a multi-stage die as
opposed to being welded to collar 34. A first stage of a
multi-stage die may form the basic features of collar 34.
A second stage may form collar tabs 82 by removing
material to create tab apertures 92 and the shape of
collar tabs 82. A third stage of a multi-stage die may
bend collar tabs 82 approximately 90 degrees such that
they are in the position shown by FIGURE 2D.
Similar to the formation of collar tabs 82, lid tabs
86 may also be formed by a multi-stage die. A first
stage of a multi-stage dye may form the basic shape of
lid 36. A second stage may remove material to form the
shape of lid tabs 86 and apertures 84. A third stage may
bend lid tabs 86 approximately 90 degrees to the position
shown in FIGURE 2D.
Collar tabs 82 may be spaced 3 inches apart and lid
tabs 86 may be spaced 3.17 inches apart. Coupling lid 36
to collar 34 may be accomplished by aligning collar
apertures 92 with lid apertures 84 and inserting cotter
pin 90 through the four apertures. In accordance with a
particular embodiment of the present invention, lid stop
60 may be formed and function in accordance with the
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teachings of United States Patent Application Serial
Number 11/563,992, which is hereby incorporated by
reference as if fully set forth herein, and be inserted
between collar tabs 82. Cotter pin 62 may couple lid 36,
lid stop 60, and collar 34.
Tank assembly 20 may conform to the ASME code for
pressure vessels, Section VIII, Division I or U.S.
Department of Transportation regulations governing
portable cylinders, NFPA 58. In compliance with ASME
standards, the maximum allowable working pressure may be
250 PSIG at 125 degrees Fahrenheit. The minimum design
metal temperature ("MDMT") may be -20 degrees Fahrenheit
at 250 PSIG. The hydrostatic test pressure of tank
assembly 20 and the maximum allowable stress of top head
40, bottom head 38, and shell ring 42 may be in
compliance with ASME or DOT standards. The weight of
tank assembly 20 including the valve fittings may be
approximately 320 pounds. The outside surface area may
be 35 square feet, and the relief capacity required for
LPG may be 990 standard cubic feet per minute.
FIGURES 3 and 5 illustrate an embodiment of the
present invention. FIGURE 3 is a side view of
semitrailer 110 loaded with tank assemblies or vessels in
accordance with an embodiment of the present invention.
The tank assemblies or vessels may be 119 water gallon
vessels. FIGURE 5 is an end view of loaded semitrailer
110.
As shown in FIGURE 3, loaded semitrailer 110
includes trailer bed 112. Trailer bed 112 may have a
length R and a width W. Length R may be 48 feet and
width W may be 102 inches. Length T and width W may be
required to comply with federal size regulations for
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commercial motor vehicles, and thus may have particular
length and width requirements. Multiple LPG tank
assemblies 100 are shown on trailer bed 112. In
accordance with a particular embodiment of the present
5 invention, LPG tank assembly 100 may have height Q and
outer diameter Y (see FIGURE 5) that allow a maximum
number of LPG tank assemblies 100 to be loaded and
transported on trailer bed 112.
LPG tank assemblies 100 may be positioned on trailer
10 bed 112 in groups of nine. As shown in FIGURE 5, three
LPG tanks 20 may be positioned substantially tangent to
each other while laying on their sides. Three tank
assemblies 100 may rest on shipping timbers 114. When
tanks 100 are positioned substantially tangent to each
15 other, they may occupy an overall tank width X. X may
equal 8 feet 3 inches (99 inches) . Shipping timbers 114
may be 1 and 11/16ths inches thick. The overall height
of loaded semitrailer 110 from the level of the ground to
the top of the tank stacks is shown as dimension U.
Height U may be selected to be less than certain state
regulations governing the maximum height of a load
carried by commercial motor vehicles. This maximum
height may be 13 feet 6 inches. Dimension U may equal 12
foot 8 and 5/8ths inches.
In accordance with a particular embodiment of the
present invention, between each tank 100 may be material
to protect each tank from contacting another tank and
thereby damaging it. Protective material 118, shown in
FIGURE 6, may be padding, web strapping, or compressed
foam. Protective material 118 may be selected and/or
positioned so as to not significantly increase overall
tank width X over 99 inches. Overall tank width X may be
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equal to or greater than 99 inches and less than or equal
to 102 inches.
Shipping timbers 114 may be placed on top of three
tank assemblies 100 to allow three more tank assemblies
100 to be stacked on top thereof. A stack of tank
assemblies 100 may comprise nine tank assemblies created
by stacking three sets of three tank assemblies on top of
each other. The outer diameter of tank assembly 100, Y,
may be selected such that it is less than trailer width W
divided by three.
Each stack of nine tank assemblies 100 may be loaded
onto trailer bed 112 for transport. The overall height Q
of tank assembly 100 may be selected such that it is less
than trailer length R divided by thirteen. Q may be
44.085 inches. This may allow thirteen stacks of nine
tank assemblies 100 (117 tank assemblies) to be loaded
and safely transported on trailer bed 112. The overall
length of thirteen stacks of nine tank assemblies, 13Q,
may be 47.76 feet. (44.085 inches X 13). Each stack of
nine tank assemblies 100 may be positioned on trailer bed
112 such that each tank assembly's imaginary center axis
106 is generally parallel to trailer bed 112. Each stack
of nine tank assemblies 100 may be positioned such that
base 102 of a tank assembly of a first stack is directly
adjacent and nearly contacts a lid of a tank assembly 100
in an adjacent stack.
Another embodiment of the present invention is
illustrated in FIGURE 4. Trailer bed 112 may be capable
of transporting fourteen stacks of nine tank assemblies
100 with the aid of an extension to trailer bed 112. The
extension 116 to trailer bed 112 may be approximately 1
foot 3 and 13/16ths inches long. In addition to
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extension 116, a stack of nine tanks may extend
approximately 1 foot 2 inches beyond the length of the
trailer bed 112. This extension is shown by dimension S.
In accordance with a particular embodiment of the
present invention, 126 tanks may be transported with one
trailer load. The overall length of the fourteen stacks
of tank assemblies may be 14Q. 14Q may equal 51 feet and
3 and 3/4ths inches.
FIGURE 7 illustrates a further embodiment of the
present invention. FIGURE 7 shows stacks of 320 gallon
tank assemblies or vessels 130 loaded on semitrailer 132.
Each 320 gallon tank 130 may have an overall length
dimension Z of 84 and 3/16ths inches, and an overall
radius BB of 33 inches. The overall length of six stacks
of nine 320 gallon tanks may be shown by dimension 6Z.
6Z may be less than semitrailer length R, which is 48
feet. 6Z may be equal to 42.094 feet. FIGURE 7
illustrates a side view of a 320 gallon tank load that is
similar to FIGURE 3 illustration of a 119 gallon tank
load. Thus, each stack showing three tanks 130 on top of
each other from a side view represents nine tanks
positioned similar to the configuration shown in FIGURE
5.
Accordingly, FIGURE 7 depicts fifty-four 320 gallon
vessels as they might be loaded on semitrailer 122.
Conventionally sized 320 gallon tanks would require that
less than fifty-four be transported on a 48 foot
semitrailer that complies with federal size regulations
for commercial motor vehicles. Conventional 320 gallon
tanks may be transported in loads of 45 tanks. The
teachings of the present invention may also be used for a
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400 gallon tank assembly with a 33 inch outer diameter
and a reduced length.
Although the present invention has been described in
several embodiments, a myriad of changes and
modifications may be suggested to one skilled in the art,
and it is intended that the present invention encompass
such changes and modifications as fall within the scope
of the present appended claims.
