Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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YA~WM ASSISTED MET~IOD FOR INSTALLING
A WATER PROOF LIMER
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TECHNICAL FIELD OF THE ~VE~TION
1 The present invention pertains in general to waterproof liner installat;on
systems for cargo containers and, more particularly, to a liner installation systern
utilizing only vacuum.
BACKGROUNI) OF THE INVENTION
The basic concept of providing a semi-truck trailer with a liner and
ancillary support equipment has been generally proposed in the past for various
reasons. For example, in U.S. Patent 2,712,797 a bag like flexible container is
` 10 clisclosed mounted in a dump truck trailer wherein supporting means for
~;1 collapsing the flexible container is provided such that the trailer can be used for
bulk haulage of pourable material as well as for general hauling. U.S. Patent
;~ 3,756,469 discloses a flexible liner used in a hopper vehicle, again where the
flexible liner is supported within the trailer such that it is collapsible, allowing the
trailer to be converted to general hauling. Other specialized applications for open
topped trailer liners have been proposed such as in U.S. Patent 4,186,845 wherein
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; a foamed base sheet with polymeric top sheet is proposed for creating a tub within
a trailer and U.S. Patents 3,980,196 and 4,124,136 disclose flexible liners withframework and bulk head that essentially convert the trailer into a container for
bulk cargo transport. Similarly, U.S. Patent 3,951,287 discloses a flexible liner
that is supported within a conventional semi-trailer by stretchable connectors
along the trailer sidewalls that essentially convert the trailer to bulk material
shipping.
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In contrast to the prior art concept of using a flexible liner for bulk
handling, theoretically there are other applications for use of a liner within atrailer provided such liner would be intrinsically extremely inexpensive, be readily
and conveniently installed without essentially any down time or significant
5 additional labor costs and provided that no other significant health hazard or risk
is associated with its use. For example, it is known and generally tolerated in the
trailer industry that certain types of common and ordinary goods statistically incur
significant water damage associated with conventional transportation procedures
independent of continuing efforts to prevent such shipping damage. In particular,
moisture damage to cigarette and other tobacco products during transportation is
known to be a troublesome problem in the industry, as is moisture and water
damage to various paper products and paper related articles directly attributable
to leaks in the semi-trailer. Although damages associated with such occurrences
can be considered a significant statistical risk and cost from an insurance industry
15 viewpoint, the actual effectiveness of correcting the problem by conventionalmethods (e.g., better packaging, sealing leaks in the trailer, etc.) is cost
prohibitive relative to insuring the risk. In principle, an essentially disposable
liner that could be selectively installed in a semi-trailer on an as needed basis
would represent an ide~l solution. To the best of the present inventor's
20 Icnowledge, no one has proposed a method of installing an essentially stand-alone,
disposable polyolefin film bag that could be installed in a semi-trailer on short
notice and enclose the entire cargo.
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SUMMARY OF T~E IN~ENTION
1 The present invention disclosed and claimed
herein comprises the method for installing a disposable
liner within a cargo container. The method includes
providing a cargo container having an opening and interior
s 5 sides therefor. A cylindrical shaped bag open at one end
is disposed within the container and the peripheral edges
thereof attached to the peripheral edges of the opening in
the container. A vacuum is then created in the space that
exists between the sides of the bag and the inner sides of
; 10 the container such that the sides of the bag are drawn
toward the inner sides of the container. The vacuum is
maintained until cargo is loaded into the bag and then the
vacuum is removed. After removal of the vacuum, the
peripheral edges of the bag opening are removed from the
peripheral edges of the opening in the container and the
bag closed to seal the cargo.
Accordingly, in one aspect the invention resides
in a method for installing a :Liner, comprising providing a
horizontal container having one open end and interior
sides with defined interior dimensions to allow loading
through the one opening; providing a deflated moisture
proof film liner of dimensions slightly in excess of the
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I interior dimensions of the container and having an opening
that corresponds to the container opening; disposing the
peripheral edges of the opening of the liner adjacent the
. peripheral edges of the opening of the container and
adhering the peripheral edges of the opening of the liner
to the peripheral edges of the opening in the container;
disposing outlet tubes adjacent the peripheral edges of
the opening of the container in communication with the
space between the interior of the corltainer and the
exterior surfaces of the liner such that the peripheral
edges of the opening of the liner provide a vacuum outlet;
and providing a blower in communication with the vacuum
for removing the air from the space between the liner and
the container to create the vacuum; loading material into
- 15 the interior of the liner, and closing the opening in the
liner to seal the loaded material therein.
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BRIEF DESCRIPIION OF THE DRAWINGS
For a more complete understanding of the present invention and the
~-;, advantages thereof, reference is now made in the following description taken in
conjunction with the accompanying Drawings in which:
FIGWRES 1 through 3 illustrate partial cross-sectional views illustrating
S the sequential steps associated with the method of the present invention for
~r placing a stand alone, moisture proof liner in a semi-trailer;
FIGURES 4 and 5 illustrate the free standing waterproof liner fully
installed and ready for loading of the trailer;
FIGURE 6 illustrates the moisture proof liner sealed around the cargo of
10 a loaded trailer;
FIGURE 7 illustrates vacuum assist equipment installed in a semi-trailer
before inflation of the liner; and
FIGURE 8 ;llustrates the method of the present invention utilizing only
vacuum assist inflation of the liner.
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DETAILED DESCRIPll`ION OF THE I~VENTION
The method of installing a waterproof liner according to the present
invention can perhaps be best explained and understood by reference to the
drawings. Figure 1 illustrates a conventional semi-tractor trailer 10 backed up to
a loading dock 12 with rear doors 14 of the trailer 10 opened for installation of
5 the liner 16. As illustrated, liner 16 is initially in a deflated state and, in this
embodiment~ rolled up in a tight coil. The liner 16 is essentially a large plastic
~: bag or inflatable bladder wherein the opening 18 of the liner is positioned at the
doorway 20 of the trailer. The liner is then unrolled or unfolded and stretched
out such that it extends along the floor of the trailer with the closed end at the
10 back of the trailer and the open end of the liner extending out the doorway. An
air blower 22 is positioned on the dock 12 and directed toward the back of the
trailer 10 such as to be turned on later when inflating the liner 16.
Also, a pair of vertical vacuum tubes 24 (see Figure 73 are inserted on the
interior of the sidewalls at the rear of the semi-trailer near the hinged portion of
the door 14. Each of the vacuum tubes 24 are connected via flexible hoses 26 to
the suction side of blower 22. It should be appreciated that other physical
configurations, equipment and methods of applying suction to the interior of thetrailer or cargo container between the plastic liner and the container sidewalls can
be employed in the present invention. As such, various suction tubes or other air
20 channels can be readily incorporated into the present invention, including by way
of example, but not limited thereto, horizontal tubes extending from the door ofthe trailer back into the rear of the container, air channels built into the sidewalls
of the cargo container or trailer, horizontal suction tubes along the top and/orbottom of the doorway, and the like. It should be further appreciated that the
25 vacuum tubes ~4 of the drawing as well as any equivalent structure according ~o
the present invention should be perforated (not shown) along the device such as
to withdraw air potentially trapped between the expanding plastic liner and the
sidewalls confining the liner.
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Figure 2 illustrates liner 16 fuZly extendecl in the trailer 10 wi~h the liner
opening 18 being mounted directly to the air outlet side of the blower 22.
Various alternative methods of attaching the liner 16 to the air supply can be
employed. Thus, the opening 18 can be connected directly to the blower outlet
5 as illustrated or can be attached to various types of nozzles, connectors or the like
which in turn are fed air from a blower, air mani~ld or even compressed gas
cylinder or other equivalent source. Similarly, it is envisioned that the vacuumtubes 24 can be physically at~ached through various types of nozzles, connectors,
or the like, to any appropriate vacuum source, including the inlet side of the
10 blower, or other equivalent low pressure device or equipment.
Having secured the opening 18 of the liner l6 to the blower 22, the blower
22 is then turned on and a gentle stream of air is directed into the liner 16. The
air is selectively directed to the front of the trailer 10 (see Figure 3) such that the
liner 16 inflates to the ceiling of the trailer in the front portion of the trailer first.
15 The blower 22 continues to gradually fill the liner 16 from the front of the trailer
to the rear of the trailer. To assist in this critical inflation step, tension can be
selectively applied to the upper surface of the liner 16 by manually pulling
downward and outward on the upper edge of the liner 16, if necessary.
Experience indicates that if the liner l 6 is not inflated from the fIont to the rear,
20 thus systematically displacing any trapped air behind the bag, the entire liner 16
will tend to exit the trailer during the inflation step. Experience further indicates
that when applying sufficient suction to the region between the liner 16 and
confining sidewalls as the liner 16 inilates, the tendency of the liner 16 inside the
trailer to be forced out of the trailer is significantly reduced.
In view of the above step, it is also critical that the dimensions of the liner
16 be selected such that it will fit the entire interior of the trailer. Preferably, the
liner IS is a cylindrically shaped bladder having a diameter slightly greater
than the larger of the width or height of the inside of the trailer.
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As illustrated in Figures 4 and 5, once the bag liner 16 is fully inflated,
the opening 18 can be removed from the air source and the liner 16 can be
attached to the perimeter of the trailer doorway 20. In the specific embodimentsof the drawing, the tension bars 28 and 30 are used to temporarily seal the bag
S opening 18 at the trailer doorway 20. Continued application of suction is an
acceptable alternative to the use of tension bars. Also, any temporary sealing or
fastening m~ans or method well known in the art can be employed to temporarily
attach the liner 16 to the doorway. The trailer is now ready to be loaded in a
conventional manner. During loading, the blower may also remain in operation.
10 However, the liner 16 once correctly inflated and sealed at the trailer doorway
tends to remain in an inflated state for a considerable period of time, even without
air or suction assist. After loading the cargo into the trailer, the blower is turned
off and the excess liner material is wrapped around the end of the cargo and
sealed such as to insure a moisture proof enclosure surrounding the entire cargo15 (see Figure 6).
As previously stated, the liner 16 or inflatable protective bladder of the
present invention is preferably a thin polymeric film bag of sufficient size to make
contact upon inflation with the entire interior of the enclosure. It is contemplated
that the liner 16 can be made of any of the conventional film grade polymeric
20 compositions, including by way of example, but not limited thereto, polyolefins
such as high density polyethylene, low density polyethylene, polypropylene and
blends thereof, film grade vinyl polymers as well as natural polymeric materialssuch as cellulose type films. The class of polymeric film compositions that has
been found to be particularly useful in the manufacturing of the plastic liner 16
25 are the film grade blends of high density polyethylene with low density
polyethylene. The liner 16 is being contemplated as being capable of being
. ~ fabricated from a series of polymeric strips or sheets which are adhesively bonded
or heat sealed along longitudinal seams to each other to form the liner 16. The
liner 16 can also be extruded in a single sheet or cylindrical tube provided an
30 extrusion dye of sufficient size is available. If longitudinal pieces are to be sealed
together to make the liner 16, the use of a thicker film for the floor, along with
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color pigmentation and non-slip additives to identify the floor versus the sidewalls
can be incorporated into the constrllction of the liner 16. Experience indicatesthat when polyolefins such as polyethylene blends are used, the liner 16 can be
made out of a relatively thin film. A 2 mil polyethylene f1lm has been
S successfully tested under conventional interstate commerce transportation
conditions and has proved to be quite adequate for purposes of this invention. In
fact, such liners have exhibited the ability to be reused if desired, but the
inexpensive nature of the thin film would not necessitate reuse and is highly
suggestive of disposing of the liner 16 after one shipment.
The actual time, effort and equipment employed to install the liner 16 is
surprisingly nominal. Under conventional semi-trailer dock loading procedures
and environment, the time reqllired to actually inflate the liner 16 has been
measured to be as short as 30 seconds. The procedure employed during this
observation was essentially as illustrated in the ~rawing and involved air
movernent equivalent to that produced by a conventional air blower or air fan.
The use of polyolefin film liners of the present invention is particuiarly
;~ useful to protect tobacco produc~s, paper products, foods and drugs, as well as
other highly moisture sensitive cargo. The liners are also useful in shipping cargo
that require ultra clean or an uncontaminated environment and could also be
readily adapted to be used to maintain an inert vapor phase or gaseous
environment. It is envisioned that the method of installing the film liner can be
advantageously employed in semi-trailers, cargo containers or generally any
equivalent transportation or storage facility wherein an inexpensive, throw-away: plastic liner would be appropriate.
Referring now to FIGURE 8, there is illustrated an alteMate method for
practicing the invention. The blower 22 is operated such that it only draws a
vacuum through hose 26 frorn vacuum tubes 24. These vacuum tubes 24 in the
preferred embodiment draw a vacuum along the sides of the interior of the trailer
to evacuate a space 28 between the bag 16 and the trailer body 10. The trailer
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body 10 is essentially a semi-sealed enclosure such lhat a negative pressure is
created in space 28 when a vacuulll is drawn througll hose 26 by blower 22. The
vacuum or negative pressure in space 28 causes the bag 16 and the surfaces
thereof to raise upward against the sides of the trailer body 10 due to atmospheric
5 pressure existing on the interior of the bag i6. In order to provide a sufficient
seal for space 28, the edges of the bag 16 proximate to the periphery of the trailer
are attached by clamps 32 to the edge of the trailer. The clamps are any type ofC-type clamp which can grip the edge of the peripheral rim of the trailer.
In operation, the bag is first laid out in the conventional manner, as
10 described above, in the trailer and then the peripheral edge at the opening of the
bag is attached to the peripheral edge of the trailer opening. These edges are then
clamped to provide a seal and then the blower 22 is turned on to produce a
negative pressure in space 28. This causes the sides of the bag 16 to rise upward
against the inside surfaces of the trailer body 10. However, it is not necessary15 for the bag to actually touch all sides of the trailer. It is therefore unnecessary
to have the air blowing in the interior of the bag to create a positive pressure on
the inner surfaces and, therefore, the operation is significantly simplified.
Although the preferred embodiment has been described in detail, it should
be understood that various changes, substitutions and alternations can be made
20 therein without departing from the spirit and scope of the invention as defined by
~he appended claims.
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