A portable folding water tank which is reversible and can present one of two colors for military camouflage purposes. The tank has a shape of a truncated cone and includes filler pipe means at the bottom. A cover which can also serve as a carrier for the folded tank is also provided.

A collapsible, portable, open-top container for liquids, preferably water, 
having a bottom and side walls made of a flexible, high-tensile-strength 
material, and a ring-shaped float body disposed along the upper edge 
portion of the side walls, said float body in its entirety being disposed 
inwardly of the circumference of said bottom. When the container is filled 
with water it rises to its full height and the side walls converge 
strongly toward the top such that the container assumes the shape of a 
truncated cone and thereby becoming quite stable with respect to loading 
on the upper edge of the walls and in regard to the nature of the 
foundation on which it rests. The invention container can be placed on an 
uneven or even or sloping foundation and makes a very practical water 
reservoir for various purposes. 
The present invention relates to a collapsible, portable, open-top 
container for liquid, preferably water, of the type defined in the 
preamble of the appurtenant main claim. 
The known containers of the above type are primarily utilized as swimming 
or wading pools for children and are therefore provided with vertical or 
slightly inwardly-sloping walls with a float body disposed at the inner, 
upper edge of the wall, such that one obtains a free water surface 
approximately as large as the pool's ground surface. 
A pool of this type has to rest on an approximately horizontal and level 
foundation so that the ring-shaped float body at the upper edge of the 
side walls will lie interiorly of the perimeter of the pool bottom and 
will thus float on the water and hold the side walls of the pool upright. 
Such a pool cannot withstand very much loading at the upper edge of the 
side walls, as too much pressure will cause the wall to collapse and allow 
the water to spill over the edge. 
The object of the present invention is to provide a container of the 
above-defined type which is substantially less critical with respect to 
loading on the upper edge of the walls and in regard to the nature of the 
foundation on which it rests. 
This is obtained according to the invention in that the container is formed 
with a top opening whose diameter is substantially smaller than the 
diameter of the bottom, the side walls converging strongly upwardly from 
the bottom periphery to the periphery of the opening, such that the 
container assumes the shape of a truncated cone if the bottom and opening 
are circular in shape, which is the most practical embodiment. 
A collapsible and portable container of this type, which can be placed on 
an uneven or even or sloping foundation and which rises to its full height 
when filled with water, makes a very practical water reservoir in 
connection with a unit for producing hot water and optionally steam for 
various purposes, for example, for relief operations in connection with 
natural disasters or for military operations. The container should 
therefore be provided with at least one sealable pipe connection at the 
lower edge portion of the side wall for tapping/filling the reservoir. By 
providing said pipe connections with threads, filling and tapping hoses 
can easily be connected to the container. One must be able to seal off the 
pipe connections, and for this purpose screw caps or screw plugs can be 
provided which cooperate with respective external or internal threads in 
the pipe. In addition, the pipe connections should be provided with a 
check valve to prevent water from flowing out when the closure means is 
removed, this value consisting, for example, of a movable flap secured 
inside the container at the upper edge of the opening for the pipe 
connection in the container wall, with a cord attached to the flap and 
passing up over the upper edge of the container and down the outside of 
the container to the removable closure means for the pipe connection. The 
check valve can be opened by pulling the cord after the closure means has 
been removed from the end of the pipe connection to permit water to be 
tapped from the container. 
Since the container may be used during military operations, as mentioned 
above, the color of its exterior surface ought to blend in with the 
surroundings. The container is therefore made of a relatively dark-colored 
material on one side, e.g., olive green, and a light-colored material on 
the other side, preferably white. As the container material is flexible, 
the container can easily be turned inside our so that one obtains the 
desired color on the exterior for summer or winter conditions. 
Since the container is reversible for camouflage purposes, it must be 
provided with two sets of pipe connections with check valves which work in 
opposite directions, so that filling and tapping hoses can be connected to 
outwardly-projecting pipe connections no matter which side of the 
container is facing out. 
For camouflage purposes, the container may be made of a material which does 
not reflect infrared rays, so that a container which is relatively large 
can not be discovered by means of binoculars or instruments which register 
infrared rays. 
In some instances, it may be desirable to transport the container, filled 
with water, on a truck, and it is then important to ensure that the upper 
edge of the container cannot move back and forth with changes in 
acceleration/deceleration or move to the sides when rounding curves, as 
the edge of the opening would become lowered during such movement and the 
water would spill out. 
To prevent such movement of the upper portion of the container, 
outwardly-projecting loops are attached to the upper edge of the 
container, four such loops, for example, being provided for attachment to 
guy ropes which can then be secured to the longitudinal sides of the truck 
bed and to its forward and rear edges. 
To close the opening of the container, a cover made preferably of the same 
material as the container is provided, being circular in shape and having 
a plurality of openings around its periphery through which a drawstring is 
threaded, such that the edges of the cover can be folded in beneath the 
lower edge of the ring-shaped float body at the opening of the container. 
The cover thus has a diameter which is somewhat larger than the diameter 
of the opening. The cover can also be used as a casing for the collapsed 
and folded container, the container being placed as a compact package on 
the cover and the outer edges of the cover being drawn up around the 
package by means of said drawstring.

FIG. 1 shows the container 1 with side walls 2 and an opening 3 at the top 
surrounded by a ring-shaped float body 4 secured to the upper edge of the 
wall 2. The bottom 5 of the container and the opening 3 are circular in 
shape, the ratio between the respective diameters of the top opening 3 and 
the bottom 5 being about 1:3. The height of the container is about 1.6 
times the diameter of the opening 3, and the container is thus cone-shaped 
with the side walls 2 converging from the circumference of the bottom 5 to 
the circumference of the top opening 3. 
The container 1 may, for example, have a bottom diameter of 3 m, an opening 
diameter of 1 m and a height of 1.60 m. The container is made of a 
water-tight, flexible material of high tensile strength which is 
preferably dark-colored on one side and light-colored on the other, 
preferably olive green and white, respectively. This is to enable the 
container to blend with its surrounding both summer and winter, as the 
container can be reversed to obtain the desired exterior color. 
When the container is being filled from the flat position shown in FIG. 2, 
the ring-shaped body 4 will float on the water collecting in the bottom 5 
of the container and will draw the side walls 2 up as the water rises 
until the container assumes the position shown in FIG. 1, being then in 
the shape of a truncated cone. The container can be filled by means of a 
hose placed over the edge of the opening 3, or with a hose which is 
connected to a filling/tapping pipe connection 6, as shown in FIGS. 1 and 
6. The pipe connection 6 is primarily intended for tapping water from the 
container; a hose is screwed onto the pipe connection 6, which is 
optionally provided with threads or other coupling means, and the hose is 
taken to the location where the water is needed. 
The pipe connection 6 as shown in FIG. 6, is secured to the side wall 2 of 
the container 1 near the bottom 5 by means of annular flanges 7,8 which 
are interconnected by means of screws or bolts 9. As shown in FIG. 6, the 
flange 8 is attached to the interior end of the pipe 6 inside the 
container, the pipe passes out through an opening in the side wall 2, and 
the flange is then slipped onto the pipe and secured to the flange 8 by 
means of said pins or bolts 9. The pipe connection 6 is provided with 
threads 10 on the outer end thereof, and a screw cap 11 screwed on to seal 
the pipe. At the interior end of the pipe connection 6 and attached to the 
upper edge of the flange 8 is a flap 12, which is movable toward and away 
from the flange 8 but which will lie sealed against the interior end of 
the pipe 6 owing to water pressure against the flap. In order to open the 
flap 12 and thus to permit water to be withdrawn through the pipe 6 when 
the screw cap 11 has been removed, a cord 13 is attached to the flap 12, 
passing up over the upper edge of the container and down to the screw cap 
11, where it is secured to an eye 14. By pulling the cord 13, the flap 12 
can be pivoted away from the pipe end 6, permitting water to flow freely 
out through the pipe connection 6 and optionally into a hose connected to 
the pipe. 
The container 1 is preferably provided with at least two pipe connections 6 
for the connection of filling and tapping hoses, respectively. In 
addition, since the container is reversible for adaption of its color to 
the surroundings, the container must be provided with an additional set of 
pipe connections and check flaps projecting in the opposite direction from 
the first mentioned pipe connections. Screw caps 11 are also secured to 
the pipe connections projecting inwardly in the container to prevent an 
outflow of water through these past the flaps 12. The second pipe 
connection is shown in FIG. 1, the two are the same except that they 
connect to the container to permit flow in opposite directions. 
To prevent dust and other material from entering the container through the 
top opening 3, a cover 15 as shown in FIG. 4 is provided, preferably made 
of the same material as the container 1. The cover is circular in shape 
and is provided with a plurality of holes 16 along its periphery through 
which a drawstring 17 is threaded. When the cover is placed over the 
opening 3 and float body 4, its outer edge region will close around and 
beneath the float body 4 when the drawstring 17 is tightened, such that 
the cover will remain firmly in place. 
Alternately, the cover 15 can be provided with fastener means in the form 
of a VELCRO (registered Trade Mark) fastener, the two cooperating fastener 
members being disposed on the cover and on the upper portion of the 
container. The cover is secured by pressing the VELCRO members together, 
and removed by tearing the fastener members apart. 
In still another alternative embodiment of the cover 15, belts having a 
number of holes can be secured to the periphery of the cover for 
engagement with buckles on the upper portion of the container, or 
vice-versa. 
In FIG. 3, the container is shown partially folded into a compact package 
18. The package 18 can be placed on the cover 15 and the edges of the 
cover drawn up around the package and brought together by tightening the 
drawstring 17, such that the cover then forms a casing for the collapsed 
container as shown in FIG. 5, where two loops 19, for example, are 
provided in addition to the drawstring 17 and can be used as handles for 
carrying the container. 
The container 1 with the accessory equipment shown in FIGS. 4 and 6 is well 
suited for use as a water reservoir in connection with a unit for 
producing hot water and steam under various conditions, for example, for 
relief actions following a natural disaster or for military operations, 
and in particular in connection with the production of hot water and steam 
for field hospitals, and for washing and cleaning of equipment and 
personnel in ABC attacks. 
One or several such containers 1 are placed at an appropriate location and 
hoses connected to pumps are coupled to the container's filling pipe 
connection 6 to fill the container with water, and a tapping hose is 
connected to a second pipe connection 6 to transport the water to a 
suitable heating unit, from which distribution hoses for the water and/or 
steam produced are led to the desired locations. 
The advantage of using a container of the type described above rather than 
pumping water directly from a lake, river or stream is that the container 
can be filled even if the pumping capacity is limited, whereas the 
emergency water requirements for short periods may exceed the pumping 
capacity. 
Several containers may also be connected either in series or in parallel, 
such that a water reservoir of the desired size may be provided. 
The container 1 can also be transported on the bed of a truck in the filled 
state. It must then be provided with loops 20 at the upper edge thereof to 
which guy ropes can be attached. The guy ropes are then secured to the 
longitudinal sides of the truck bed and to its front and rear ends in 
order to prevent the upper portion of the container with the opening 3 
from moving back and forth when accelerating/decelerating and from moving 
sideways when rounding curves, thus ensuring that the top edge of the 
opening remains stable so that the water cannot spill over the edge.