[0001] This invention relates to improvements to a flexible liner for an 'ISO container.
[0002] ISO containers specially adapted for the carriage of bulk cargo are well known, and
generally comprise a large rectangular prismatic shaped container specifically designed
in modular sizes to fit on road trailers, rail trucks and container-carrying ships.
The top of the container will generally incorporate one or more hatches to facilitate
filling of the container, and some form of hatch in the lower part of one end to allow
discharge of the product. The product is most commonly discharged by tipping the whole
container, so that it flows out through the hatch into a hopper, rotary valve or other
means by which it is transported to a silo or other receptacle.
[0003] When such containers are filled with bulk cargoes, it is common to fit a liner made
from a flexible film or material inside the container. This encapsulates the product
and isolates it from the container, thereby preventing contamination of the container
by the product, or contamination of the product by moisture ingress, residues already
in the container or from other sources.
[0004] The liner is usually fitted with filling sleeves located to match the positions of
the hatches at the top of the container, and a hanging system to suspend it within
the container. The liner also incorporates a discharge sleeve which is situated behind
the discharge hatch. This discharge sleeve is commonly of triangular or fishtail shape,
and is folded so that when the hatch is opened, it may be unfolded and used to direct
the contents into a suitable receptacle.
[0005] When the liner is filled, the filling sleeves are tied off, or closed in other suitable
fashion, and documents relating to the consignment are commonly put into a pouch attached
to the top of the liner before the hatches are closed and transport seals fitted to
all doors and hatches.
[0006] When the loaded container has been transported to the delivery point, it has been
the practice to climb onto the top of the container and open one or more hatches,
both to recover the documentation from the document pouch, and to open one or more
filling sleeves to permit the ingress of air to replace the product as it is discharged.
It is furthermore common practice for the customer to require a sample for testing,
and this is also taken through the top filling sleeves.
[0007] All the foregoing operations on the top of the container carry some measure of risk,
both to the operator who climbs onto the top in what may be icy or wet conditions,
and to the product which could be contaminated by the ingress of pollutants through
the opened filling sleeve.
[0008] It has been proposed that the document pouch should be sited under the discharge
hatch, so that the operative does not need to climb onto the top of the container,
and also that the sample should be taken from around the discharge area for the same
reasons. However, if the discharge hatch is opened after the container has been filled,
the pressure of the product within the liner will make it bulge out through the hatch
aperture, thereby preventing subsequent closure of the hatch, either for subsequent
sealing and transport, or to await the results of sample checking.
[0009] According to the present invention there is provided a liner for a bulk cargo container
having a cargo discharge hatch, the liner comprising support means in the region corresponding
to the discharge hatch to prevent bulging of the liner through the discharge hatch.
[0010] By preventing the liner from bulging through the discharge hatch it is possible for
pre-discharge requirements to be met without the driver or operator needing to go
on top of the container. In particular, documentation relating to the content of the
liner can be kept in a pouch behind the discharge hatch for inspection because the
discharge hatch can be easily closed again. It is also possible to discharge the contents
of the liner without it being necessary to open the filling sleeves to permit ingress
of air, and to take samples of the content of the liner through the discharge hatch.
[0011] Preferably, the support means is movable from a first position in which it supports,
and prevents bulging of the liner to a second a position in which the liner is not
supported.
[0012] Preferably, the support means for preventing bulging of the liner comprises a flap
formed from a sheet of strong flexible material which is preferably adapted to be
anchored along one edge between the lower face or floor of the liner and the container
floor, and which is also preferably adapted to be secured to the container body at
a point or points above the discharge hatch.
[0013] The liner may further comprise a discharge sleeve which is normally covered by the
flap.
[0014] In a preferred embodiment of the present invention the flap is attached to the liner
itself. By virtue of the edge of the flap being attached to the floor of the liner,
the edge is trapped and secured in place under the weight of the liner when filled.
Conveniently, the edge of the flap is attached to the floor of the liner by adhesive
tape or similar, but it will be appreciated that other attachment means may be employed.
However, the flap may be attached to the floor of the container and/or it may be of
sufficient length to extend under the liner whereby the weight of the filled liner
acts on the flap, thereby ensuring that it is trapped by the weight of the liner when
filled.
[0015] With the edge of the flap firmly secured to the floor of the liner it can be pulled
up to cover that part of the liner which lies behind the discharge hatch and anchored
in position to the container body so as to be taut enough to prevent bulging of the
liner and the discharge sleeve, if present. Conveniently, the flap may be anchored
to the container using hooks or similar devices already provided in the container
for the purpose of hanging the liner, or purposely designed anchor points can be provided
in the container. Where the container anchors take the form of hooks, reinforced eyelets
may be provided in the sheet which can be positioned over the hooks.
[0016] Preferably, the flap is anchored prior to filling the liner and is anchored in such
a way as to lift the front edge of the floor of the liner from the floor of the container,
thus ensuring that as the liner is filled the sheet is tautened.
[0017] The sheet preferably comprises a material which is not prone to stretching, such
as heavy duty polythene or polypropylene. The material may also comprise a reinforced
plastics sheet. Conveniently, a rip cord is provided in the sheet which may be used
to cut through the sheet when discharging of the liner is to be carried out. Once
the sheet has been cut through the discharge sleeve is made accessible. Also, a document
pouch may be provided in the sheet.
[0018] In order to facilitate pre-discharge sampling of the contents of the liner a small
sleeve may be provided in that part of the liner which is accessible in use through
the open discharge hatch. Conveniently, this sleeve is provided in the liner at the
side thereof where the liner content is likely to remain quite static. The sleeve
is usually closed off to prevent product from leaking out through it, but can be opened
to allow a sample of product to be taken, or to admit a test probe. The sampling tube
may be positioned to one side of the said sheet or it may pass through a hole in the
sheet.
[0019] The flap may extend over the liner so as to substantially fully cover that area of
it which is exposed when, in use, the discharge hatch is opened. However, because
the product tends to be static along the sides of the liner so that it tends to bulge
in the middle, it may conveniently be triangular in shape so as to cover only that
part of the liner which is subject to bulging.
[0020] Preferably, a self venting port is provided in the liner which obviates the need
for one or more of the filling sleeves to be opened prior to discharge. This conveniently
takes the form of an aperture in the wall of the liner which aperture is filled with
an air permeable material which admits air, but prevents ingress of dust and other
contaminants. This aperture is covered by an impermeable sheet which is folded, pleated
or otherwise shaped to form corrugations so that air can be admitted but water or
condensation will run off.
[0021] The present invention also includes a liner in accordance with the present invention
in combination with a tank container.
[0022] An embodiment of the present invention will now be described, by way of example only,
with reference to the accompanying drawings, in which:-
Fig. 1 shows the discharge or rear end of a bulk liner according to the present invention;
and
Fig. 2 shows the front end of the bulk liner with the venting aperture therein and
covering flap.
[0023] Referring to Fig. 1 there is shown the discharge or rear end of a bulk liner 10 for
an ISO container, with filling sleeves 11 and a discharge sleeve (not visible) located
towards the bottom thereof, behind a triangular flap 12. The bottom edge of the flap
12 extends under the liner 10 for a distance and is secured thereto by welding or
adhesive tape. Towards the apex of the flap 12 is provided a reinforced attachment
point consisting of an eyelet 13, which is intended, in use, to be attached to a hook
or other fixing inside the container.
[0024] In use the liner 10 is suspended within a container using conventional hangers with
the filling sleeves 11 adjacent to the filling hatches therein and the discharge sleeve
adjacent to the discharge hatch therein. The apex of the flap 12 covering the discharge
sleeve is secured to the inside of the container so as to lift the adjacent edge of
the floor of the liner and place the flap under tension. The liner is then filled.
[0025] It will be understood that the triangular flap supports and retains the weight of
the product within the liner when the discharge hatch is opened, thereby preventing
bulging of the liner which would otherwise prevent the discharge hatch from being
closed. Consequently, it is possible to carry out certain operations which would otherwise
have to be carried out through the filling hatches. Documentation can be carried on
the liner behind the discharge hatch and the product can be sampled through the discharge
hatch. To this latter end a sample extraction tube 15 is provided in the liner to
one side of the flap 12.
[0026] To facilitate hanging the liner within a container the apex of the flap 12 is attached
to the liner by means of welding or adhesive tape.
[0027] A rip cord 14 is provided behind the flap 13 and extends the full width of the flap
13. By pulling on the free end of the rip cord 14 it is possible to cut across the
flap 13 to make the discharge sleeve in the liner accessible.
[0028] Referring to Fig. 2 there is shown a venting port provided in the front or forward
face of the liner. This venting port comprises an aperture filled with air permeable
material 18 and covered by a pleated or corrugated flap 19 of water impermeable material.
The flap hangs down over the aperture to prevent water or condensate seeping into
the liner, but allows air to pass freely through the pleats therein.
1. A liner for a bulk cargo container having a cargo discharge hatch, the liner comprising
support means in the region corresponding to the discharge hatch to prevent bulging
of the liner through the discharge hatch.
2. A liner as claimed in claim 1, wherein the support means is movable from a first position
in which it prevents bulging of the liner to a second position in which the liner
is not supported.
3. A liner as claimed in claim 1 or claim 2, wherein the support means comprises a flap
formed from a sheet of flexible material.
4. A liner as claimed in claim 3, further comprising a discharge sleeve which, in use,
is covered by the flap.
5. A liner as claimed in claim 3 or claim 4, wherein the sheet of flexible material is
adapted to be anchored along an edge between the lower face or floor of the liner
and the floor of the bulk cargo container.
6. A liner as claimed in claim 5, further comprising means for securing the flap to the
container body at a point or points above the discharge hatch.
7. A liner as claimed in any of claims 3 to 6, wherein the flap is attached to the liner.
8. A liner as claimed in claim 7, wherein an edge of the flap is attached to the floor
of the liner.
9. A liner as claimed in any of claims 3 to 8, wherein the edge of the flap is attached
to the floor of the liner by means of adhesive tape.
10. A liner as claimed in claim 8 or claim 9, wherein the flap is of sufficient length
to extend under the liner whereby the weight of the filled liner acts on the flap.
11. A liner as claimed in any of claims 3 to 10, wherein the flap can be positioned to
cover that part of the liner which, in use, lies behind the discharge hatch of the
container, the liner further comprising means for anchoring the flap to the container
body in a condition sufficiently taut to prevent bulging of the liner.
12. A liner as claimed in any of claims 3 to 11, wherein the flap comprises means for
releasable connection to an anchor point of a container.
13. A liner as claimed in claim 12, wherein the flap comprises a reinforced eyelet.
14. A liner as claimed in any of claim 12 or claim 13, wherein when the flap is secured
to an anchor point of the container, the front edge of the floor of the liner is lifted
from the floor of the container.
15. A liner as claimed in any of claims 3 to 14, wherein the flap comprises a rip cord
for severing the flap to allow discharge of the cargo.
16. A liner as claimed in any of claims 3 to 15, wherein the flap comprises a document
pouch.
17. A liner as claimed in any of claims 3 to 16, wherein the flap extends so as to cover
substantially the whole of the area of the liner which is exposed when, in use, the
discharge hatch is opened.
18. A liner as claimed in any of claims 3 to 17, wherein the flap is triangular in shape.
19. A liner as claimed in any of claims 3 to 18, wherein the sheet comprises a material
which is resistant to stretching.
20. A liner as claimed in claim 19 wherein the sheet comprises polythene.
21. A liner as claimed in claim 20, wherein the sheet comprises heavy duty polythene.
22. A liner as claimed in claim 19, wherein the sheet comprises polypropylene.
23. A liner as claimed in any of claims 19 to 22, wherein the sheet comprises reinforced
plastics.
24. A liner as claimed in any of the preceding claims, further comprising a sleeve formed
in a part of the liner which is accessible in use through an open discharge hatch
of the container.
25. A liner as claimed in claim 24, wherein the sleeve is provided at the side of the
liner.
26. A liner as claimed in any of the preceding claims, further comprising a self-venting
port.
27. A liner as claimed in claim 26, wherein the self-venting port comprises an aperture
in the wall of the liner filled with an air-permeable material.
28. A liner as claimed in claim 27, further comprising a liquid-impermeable sheet located
over the air-permeable material.
29. A liner as claimed in claim 28, wherein the liquid-impermeable sheet is folded, pleated
or otherwise shaped to form undulations to allow air to reach the air-permeable material
but to allow liquid to run off.
30. The combination of a tank container and a liner as claimed in any of the preceding
claims.