Note: Descriptions are shown in the official language in which they were submitted.
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Bag System for Transpbrtation bf Bulk I.iquids
This invention relates to a flexible bag system for the
transportation of bulk liquids and to the use thereof. Such
a system is particularly suitable for the transportation of
non-hazardous liquids in bulk quantities, such as chemical
liquid products and detergents, as well as heavy liquids,
such as latex, palm oil, molasses and even some foodstuffs,
although in the case of products for human consumption special
hygiene conditions may dictate the need for additional pre-
cautions beyond the concern of the present invention.
Theoretically, such a bag system can even be used for
the transportation of flowable solids, although these often
present caking and similar problems that may render them
ùnsuitable for transportation in such a system. Neverthe-
less, it is to be understood that, in referring to the trans-
portation of "liquid" in bulk, the present specification is
not intended to exclude a flowable solid that performs
essentially as a liquid and is suitable for shipping by a
flexible bag system.
It is already known to use bag systems for the trans-
portation of bulk liquids. Such bags can be mounted in
standard, dry, van type containers or the like, such con-
tainers being suitable for piggy-back transfer between road
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vehicles, rail vehicles or water borne vessels.
Flexible bags of tough sheet material have been
developed for this specific purpose and are typically
mounted in a standard container and secured therein by a
harness of strapping. The bag is inserted into the
container empty, filled, then transported in the container
to the desired destination and there emptied. The filling
and emptying processes are carried out by suitable pumping
devices. In the past the empty bags have been designed to
be returned to the point of origin for reuse. However,
increasing transportation cost for returning the bags has
often resulted in their being simply discarded.
The principal object of the present invention is to
provide a third alternative, namely one that enables
useful utilization of the bags, while at the same time
avoiding the cost of their return shipment.
To this end the invention can be defined as a bag of
tough, flexible sheet materal for mounting in a standard
freight container to transport a liquid in bulk, said bag
having a central, generally cylindrical, elongated portion
extending into curved end portions and being liquid tight
except for controlled access means for filling and emptying
the bag, including a series of substantially uniformly
spaced-apart tie down means secured to said material, said
tie down means being arranged in a pair of circumferential
rows extending around the periphery of the central portion
near each end portion and in a further pair of parallel
rows extending longitudinally adjacent each other along the
central portion between said circumferential rows, each of
said tie down means being independent of every other one of
said tie down means whereby to permit unrestrained
expansion of the bag, the arrangement of said tie down
means being such that after use the bag can be cut to
remove said end portions and to slit it longitudinally
between said adjacent parallel rows to provide a sheet with
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the tie down means substantially uniformly disposed around
the periphery thereof in a manner suitable for use as a
tarpaulin.
The invention also consists of a method of using a bag
of tough, flexible sheet material for the one-way trans-
portion of liquid in bulk, said bag being liquid tight
except for controlled access means for filling and emptying
the bag, said bag having a series of spaced-apart tie down
means secured to said material, said method comprising
(a) mounting the bag in a freight container and thereupon
filling it with bulk liquid, (b) transporting the freight
container to a desired destination and there emptying the
liquid from the bag, and (c) cutting the bag to form a
sheet with said tie down means disposed around the
periphery thereof to render the same suitable for use as a
tarpaulin.
Other features of embodiments of the invention are
disclosed below in connection with the accompanying
drawings which illustrate such embodiments by way of
example. It is to be understood that these embodiments do
not limit the broad scope of the present invention which
is defined in the appended claims.
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In the drawings:-
Figure 1 is a rear perspective view of a container with
a bag for transporting bulk liquid mounted therein, this view
representing the prior art;
Figure 2 is a plan view of a blank for making an
improved bag according to an embodiment of the present
invention;
Figure 3 is a fragmentary view showing one of a series
of tie down devices used in this bag;
Figure 4 is a view on 4-4 in Figure 3;
Figure 5 is a perspective view of a bag constructed from
the blank of Figure 2;
Figure 6 is a plan view of a tarpaulin cut from the bag
of Figure 5;
Figure 7 is a fragmentary sectional view of a seam formed
in the bag;
Figure 8 is.a view of a loop arrangement for use with
the bag;
Figure 9 is a view showing the manner in which the loop
of Figure 8 can be utilized;
Figure 10 is a sectional view of a filling and emptying
valve for incorporation in the bag;
Figure 11 is a sectional view of a. vent for incorporation
in the bag;
Figure 12 is a plan view of a blank for use in forming
a tray for use with the bag;
Figure 13 shows the blank o-f Figure 12 erected into a
tray;
Figure 14 is an end view of a container with the tray
of Figure 13 located therein;
Figure 15 is a view similar to Figure 14 but with the
bag now arranged inside the tray;
Figure 16 is a view corresponding to Figure 15 but show-
ing the commencement of a filling operation; and
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Figure 17 is a ~urther view similar to Figure 16 showing
the filling operation completed.
Figure 1 shows a container 20 mounted on a trailer
chassis 21 and serving to support a flexible bag 22 that is
kept in place by harness straps 23 while being filled througn
a hose 24 by means of a pump 25. Safety regulations require
that, during filling, the rear of the container 20 must be at
least partially closed off by a transverse bulkhead 26 which
in turn is firmly held in place by one of the doors 27a of the
container. The other door 27b will be closed during transit
but can be open during loading and unloading to provide
access.
Figure 2 shows a blank 22a for use in making a flexible
bag 22b according to an embodiment of the present invention
and shown constructed in Figure 5, such bag being for use in
the general manner illustrated in Figure l, but with the
additional features that will be explained.
The bag 22b will be made of a tough, flexible abrasion
resistant, sheet material. For example, the bag may be made
of a material the base of which is a polyester resin or woven
nylon, preferably coated on both sides with PVC. Alternative
base materials are cotton and woven glass and alternative
coatings are Teflon and Hypalon (a by-product of Neoprene).
Obviously, it is important that the coatings be resistant to
any chemical attack by the bulk product to be transported.
Materials of this type are well known for the purpose and
the present invention is not concerned with the choice of
specific materials.
However, a useful by-product of the non-returnable feature
of the present invention is that, for many applications, it
becomes possible to use a lighter weight of sheet material
than has hitherto been the practice. In the past, it has
been usual to construct such bags for the transportation of
bulk liquids from sheet material having a weight of around
40 ounces per square yard. This weight of material has been
* Trade Marks
~739~
found necessary in order to ensure satisfactory performance
with repeated uscs of the bag. It is a feature of the present
invention that the bag will not be returned to the point of
origin but will be utilized in a different way at the
destination location. It has been found that single use of
the bag enables a lighter weight material to be safely used,
even down to a weight of 16 ounces per square yard, although
this may require to be increased to somewhere in the range
of about 30 ounces per square yard if the abrasive content of
the liquid to be transported is relatively high. Nevertheless,
the weight for bags that are not designed for reuse can
generally be lower than the typical 40 ounces per square
yard of returnable bags, and this consideration is important
from the viewpoint of the overall economics of SUC}l an
operation.
The blank 22a shown in Figure 2 is constructed of a
series of strips 31 through 39 seamed together in the manner
that will be described below. Secured to the surface of the
blank 22a, as seen in Figure 2, is a series of tie down
devices 40 arranged in a first pair of rows 41 and 42 which,
when the bag is constructed (Figure 5), extend circumfer-
entially around the central portion 43 of the bag near the
ends of such central portion. In addition, there is a second
pair of parallel, adjacent rows 44 and 44a extending
longitudinally along the central portion between the
circumferential rows 41, 42.
Also formed in the blank 22a are a filling and emptying
valve 50, a vent 51 and a drain 52, details of which will
later be described.
Also formed on the underside of the blank 22a as seen
in Figure 2 are loops 53, details of which will also be
provided below.
To construct the bag, the edges 54a and 54b are seamed
together and in a similar manner edges 54c, 54d; 54e, 54f;
54g, 54h; and 54i and 54j are connected together to form a
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closed bag which after inversion is as seen in Figure 5.
The manner in which these edges are seamed together is
demonstrated in Figure 7, the sheet material 55 of the bag
being overlapped in the area 56 and joined together by lines
of stitching 57. A narrow strip 58 of the same material is
then placed over the lines of stitching 57 to cover the holes
and the whole assembly is subjected to a heat sealing process
whereby the seam is made liquid tight.
After use, the bag 22b is slit opened along a slit line
60 between the rows ~4 and 44a of tie down devices 40, and
is also cut along circumferential lines ~1 to separate the
central portion 43 from the end portions. The result is
the article 62 shown in Figure 6, which now has the series
of tie down devices 40 arranged substantially uniformly
around its periphery. The article 62 can be used as a
tarpaulin or like covering device, but can of course be
used for any other purpose in whicll a flat sheet with tie
down devices is usèful.
Figures 3 and 4 provide details of each tie down device
40 which consists basically of a first part 40a heat sealed
to the sheet material 55 and a second part 40b which acts as
a flap and is formed with an eye 40c of a suitable material
such as a tough, relatively rigid, durable plastic. As
shown in Figure 6, each tie down device 40 thus forms a basis
for connection of a tie down rope 63.
As already mentioned, secured, also by heat sealing, to
the underside of the blank 22a as seen in Figure 2, so as
to be on the outside of the bag 22b when it has been formed,
are a series of eight loops 53 which serve to receive and
retain straps that function as the harness 23 for retaining
the bag in place in the container.
In order to allow for appropriate tightening and
loosening of the harness straps, these need to be provided
with buckles, typical examples of which are best seen at
64 in Figure 17.
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Prior bag constructions have used simple loops for
retaining these straps, as shown at 65 in Figure 1, but
difficulty has been experienced with threading the best type
of buckles through such loops. It is desirable that the
buckles should be strong and reliable, and this requires
them to be substantially larger than the straps that they
interconnect. The prior form of simple loops 65 has,
however, tended to mitigate against the use of the better
buckles, because of their relatively large transverse
dimensions compared to that of the straps and the consequent
difficulty of threading them through a loop that will at the
same time perform a snug retaining fuction for a strap
itself, i.e. restrain transverse movement of such strap.
The present apparatus employs a novel form of loop 53
shown in Figures 8 and 9 secured to the material 55 of the
bag by heat sealing in the usual way. The loop 53 consists
of a pair of end portions 53a which are parallel to but
laterally displaced from each other. These end portions 53a
are sealed to the material 55 up to the lines 54b, leaving a
central portion 53c of the loop free from engagement with
the sheet 55. This central portion 53c of the loop thus
consists of a pair of parallel portions 53d and an inter-
connecting oblique portion 53e. With the loop lying com-
paratively flat against the sheet 55 and a strap 23 threaded
through it, as shown in Figure 8, there is comparatively
little tranverse play, the strap thus being constrained
against any significant sideways movement. However, when
it is desired to open up the loop to thread a buckle 64
through it, the arrangement permits the loop to expand
significantly and allow a buckle 64 with relatively large
transverse dimensions to pass through, as demonstrated in
Figure 9.
As previously mentioned, the bag is provided with a
filling and emptying valve 50 which is shown in detail in
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Figure 10 and consists basically of a pipe 50a secured to a
pair of plates 50b and 50c which are clamped by bolt and nut
assemblies 50d to surround a hole in the sheet 55 in a liquid
type manner. The pipe 50a is furnished with a valvc 50e and
a screw threaded end 50f for connection to an external hose,
such as the hose 24 shown in Figure 1. On the inside of the
bag, the plate 50c is provided with an inwardly projecting
ring 50g that projects beyond the end of the pipe 50a
whereby to ensure that the latter can never be occluded by
another part of the bag when the pressure therein is below
atmospheric.
As also mentioned above, the bag is further provided
with a vent 51 shown in Figure 11 as consisting of a similar
arrangement of clamped plates~ but without a valve. Instead,
it has a simple cap 51a that threads onto the pipe 51b. The
drain 52 can be similar in construction to the vent 51. If
found necessary, the vent 51 or the drain 52 can be formed
with a ring such as the ring 50g to ensure that the outlet
can never be occluded by another part of the bag.
Figures 12 and 13 show the construction of a tray 70
which can be used in conjunction with the bag. This tray 70
is formed fronl a rectangular blank 71 of similar material
to that of the bag, although it can be and usually will be
of a much lighter gauge, since it is not called upon to
withstand any significant internal pressures or abrasive
forces. The material of the blank 71 is folded along the
broken lines shown in Figure 12 to construct the tray of
Figure 13 as follows. As side and end walls 72, 73 are
folded upwardly from the central portion 78 which forms the
floor portion, a V-shaped flap 76 is formed from each corner
portion 74. With the oblique fold line 75 extending inwardly
of the tray, each triangular flap 76 is placed against a
side wall 72 as shown in Figure 13. This triangular flap 76
is then secured in place by stitching along three lines 77,
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such stitching ex-tending through three thicknesses of the
material, namely the side wall 72 and the two thicknesses
of the corner portion 7~ which has now become the triangular
flap 76. It is unnecessary to supply these seams with an
overlaid heat seal strip, because, even if the stitch lines
were able to leak somewhat, they do not extend down more than
half-way of the walls of the tray 70. While the tray is
designed to collect spillage and to protect the container
against soiling or corrosion or any other ill-effects of
escaped liquid, such liquid will normally only be present in
relatively small amounts and will not be expected to rise
above a low level in the tray. However, if preferred these
stitch lines 77 can be sealed as in Figure 7. Normally the
tray will be designed to beas cheap to make as possible, since
it will be discarded at the destination.
Figures 14 through 17 show the ~nanner of transportation
use of the equipllient so far described. Figure 14 shows the
container 20 into which the tray 70 has been placed as a
preliminary procedure. Then, as shown in Figure 15, the bag
22b, in deflated condition, is placed inside the tray 70 and
the harness straps 23 are placed over the bag, threaded
-- through the loops 53 and finally over the walls of the tray
to be secured to the standard fixings provided along the
sides of the floor of the container. Before the filling
procedure can take place, it is a safety req~irement that
the bulkhead 26 be in place and the door 27a be closed, as
shown broken away in Figure 16. Filling then takes place
through hose 24 until the final condition of a completely
filled container is achieved, as shown in Figure 17.
More specific details of this use of the equipment are
as follows.
Firstly, the container floor is swept clean, the floor,
sides and bulkhead being inspected for any sharp objects
that might damage the equipment. Then, as indicated above,
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the tray is put in place. The bag is then unrolled and placed
in the -tray. Conveniently there will be appropriate mar~ings
on the bag to assist in positioning it correctly.
The bag should lie smoot~ly on the floor of the tray
without any twists or folds. The harness of straps is then
placed over the bag and the hooks on the ends of these
straps are secured to the corresponding lashing rings pro-
vided in the container. Any slack in the straps should be
folded inward to prevent being trapped during filling and
the buckles should be released. The bulkhead is then put in
place and one door closed.
To load the bag with the liquid to be transported, the
flexible hose is connected to the filling and emptying
valve 50. If a self-sealing coupling is not used, the hose
should also include a manually operable valve to minimize
spillage. Conveniently, the weight of the hose and the valve
can be supported by a length of rope ~not~shown) attached to
the ceiling of the container.
The vent cap 51a is then removed and filling is
commenced by pumping the liquid through the hose 24. The
top surface of the bag will rise with the level of the liquid
and the harness will tighten. When it is determined that
the correct volume of liquid has been loaded into the bag,
the valve 50e will be closed and the filling hose disconnected.
The two longitudinal straps will then be tightened by means
of the buckles 64. The screw cap 51a on the vent pipe will
be closed. Finally, the second door 27b will be closed and
the container sealed.
At the destination, the door 27b will be opened but
the door 27a and the bulkhead 26 will remain in place during
unloading. A flexible suction hose will be connected to
the filling and emptying valve 50 and a positive suction
pump connected to the hose. The air vent 51 must be kept
closed while the bag is being discharged so that a partial
vacuum will be formed in the bag to cause it to collapse.
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If the contents of the bag should be particularly viscous,
final discharge of residue can be achieved by disconnecting
the suction line for a few minutes to allow the contents to
run out of the folds, after which pumping out is recommenced.
If necessary, any residual contents can be drained through
the drain 52.
The bag can then be slit along the lines 60, 61, as
already explained, with the central portion thereof becoming
the article 62 for use as a tarpaulin or the like. The end
portions of the bag are discarded. The tray will also
norma]ly be discarded. The harness system of straps and
buckles will normally be reclaimed for repeated use.
Use of the tray 70 is optional. If preferred, the bag
can be placed directly on the floor of the container.
