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Title:
COLLAPSIBLE STORAGE TANK FOR LIQUIDS
Document Type and Number:
WIPO Patent Application WO/2001/081208
Kind Code:
A2
Abstract:
A frameless liquid storage tank (10) and a method of fabricating and pressure testing the liquid storage tank. The tank is collapsible for ease of transportation when not holding a liquid and includes a base portion (11) and a top portion (16). The base portion has a bottom wall (12) and a frusto-conical sidewall (14) that is sealed to the bottom wall. The top portion is sealed to the sidewall, and has a flexible opening (18). The opening is linear in one embodiment and is openable to draw liquid from the tank and closable to prevent contaminants from entering the tank. The bottom wall is substantially circular, and the top portion includes two substantially semicircular sections (36) joined and overlapped along the straight edges to form an overlapped region (38). The sidewall includes generally triangular-shaped sections (24), and the sections are joined to one another with seams (33) that extend in slightly helical fashion about the tank. The opening includes a slit (52) in the overlapped region and two reinforcing members (42) sealed together on the ends (48) thereof. The liquid storage tank may be inverted through the opening for ease in cleaning the tank, and the tank may be filled to capacity on an incline of up to at least 10 degrees without spillage.

Inventors:
JOSHI YATISH J
ADDICOTT LOUISE E
COSTA LARRY J
Application Number:
PCT/US2001/012598
Publication Date:
November 01, 2001
Filing Date:
April 18, 2001
Export Citation:
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Assignee:
GTA CONTAINERS INC (US)
International Classes:
B65D6/16; B65D8/04; B65D88/16; (IPC1-7): B65D88/16
Domestic Patent References:
WO1989006624A11989-07-27
Foreign References:
US4124049A1978-11-07
FR2501648A11982-09-17
US5368395A1994-11-29
Attorney, Agent or Firm:
Tychonievich, Daniel (IN, US)
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Claims:
CLAIMS
1. A frameless liquid storage tank (10) comprising a base portion (11) for holding a liquid, said tank being collapsible for ease of transportation of the tank when not containing a liquid and being characterized in that said tank includes a top portion (16) sealed to said base portion, the top portion having a flexible opening (18), said flexible opening being closable to prevent contaminants from entering said tank and being openable to fill the tank or to draw the liquid stored in said tank therefrom.
2. The frameless liquid storage tank as set forth in claim 1, characterized in that said flexible opening includes a slit (52) in said top portion.
3. The frameless liquid storage tank of claim 2, characterized in that said slit is reinforced by reinforcing members (42) flanking said slit.
4. The frameless liquid storage tank of either claim 2 or 3, characterized by a pathway connected to said slit, said pathway upstanding from said top portion.
5. The frameless liquid storage tank of any of claims 24, characterized in that said opening is partially formed by two adjacent sections (46), which are partially fixed along their length, said opening being formed where said adjacent sections are not fixed.
6. The frameless liquid storage tank as set forth in any of claims 35, characterized in that the reinforcing members comprise two Lshaped members, each Lshaped member having a horizontal leg (44) and a vertical leg (46), said vertical legs being adjacent one another with said slit located at a bottom end of and between said vertical legs and said horizontal legs being sealed to said top portion of said tank.
7. The frameless liquid storage tank as set forth in any of claims 36, characterized in that the reinforcing members are made from fiber reinforced elastomeric material.
8. The frameless liquid storage tank as set forth in any of claims 27, characterized in that said opening includes a mating pair of hook and loop fastening strips (50,51), one of each of said strips attached to opposing sides of said reinforcing members to secure the tank closed and also being releasable to open said opening.
9. The frameless liquid storage tank as set forth in any of claims 18, further characterized by a foldable cover (56).
10. The frameless liquid storage tank as set forth in claim 9, characterized in that said cover is removably attachable to said Lshaped members.
11. The frameless liquid storage tank as set forth in claim 10, characterized in that hook and loop fastening material (60) is used to attach said cover to said L shaped members.
12. The frameless liquid storage tank as set forth in any of claims 111, characterized in that said tank is invertable through said flexible opening for ease of cleaning said tank.
13. The frameless liquid storage tank as set forth in any of claims 112, characterized in that said base portion includes a bottom wall (12) and a frustoconical sidewall (14) sealed to said bottom wall.
14. The frameless liquid storage tank as set forth in claim 13, characterized in that said bottom wall is substantially circular and said top wall includes two substantially semicircular sections (36) joined and overlapped along straight edges thereof forming an overlapped region (38).
15. The frameless liquid storage tank as set forth in either claim 12 or 13, characterized in that the sidewall includes generally triangularshaped sections (24) said sections joined to one another along seams (33), said seams extending in a slightly helical fashion about said tank.
16. The frameless liquid storage tank as set forth in any of claims 115 further characterized by at least one nozzle (35) in a lower portion of said base portion for filling and draining said tank.
17. The frameless liquid storage tank as set forth in any of claims 1416, characterized in that said opening is located in the overlapped region of said top semicircular sections for providing reinforcement to said opening.
18. The frameless liquid storage tank as set forth in any of claims 117, characterized in that the opening is linear.
19. The frameless liquid storage tank as set forth in any of claims 618, characterized in that said vertical legs of said Lshaped members are sealed to one another at extended ends (48) thereof.
20. The frameless liquid storage tank as set forth in any of claims 619, characterized in that a portion of said vertical legs between the sealed extended ends includes a releasable closing mechanism for opening and closing said opening.
21. The frameless liquid storage tank as set forth in any of claims 120, characterized in that said base portion may be placed on an incline of up to at least ten degrees with the tank being filled to capacity and wherein no liquid will spill from said opening.
22. A method for fabricating and testing a liquid storage tank (10) comprising the steps of providing a moistureresistant fabric material, cutting a base portion (11) and a top portion (16) from said fabric material, sealing the base portion to the top portion being characterized by the steps of pressurizing said tank and checking said tank for leaks when pressurized.
23. The method of fabricating and testing a liquid storage tank as set forth in claim 22, characterized in that said sealing is accomplished by radio frequency sealing.
24. The method of fabricating and testing a liquid storage tank as set forth in either claim 22 or 23 characterized by the step of reinforcing sealing seams of the tank with a sealant tape.
25. The method of fabricating and testing a liquid storage tank as set forth in any of claims 2225, characterized in that said base portion includes a sidewall (14) and a bottom wall (12).
26. The method of fabricating and testing a liquid storage tank as set forth in claim 25 characterized in that said sidewall has a generally frustoconical shape.
27. The method of fabricating and testing a liquid storage tank as set forth in either claim 22 or 23 characterized in that said sidewall includes generally triangularshaped sections (24) and said method includes the steps of sealing the triangular shaped sections to one another to create seams therebetween extending in a slightly helical fashion about said tank.
28. The method of fabricating and testing a liquid storage tank as set forth in any of claims 2227 characterized by the step of providing a reinforcing member on said top portion.
29. The method of fabricating and testing a liquid storage tank as set forth in any of claims 2228, characterized by the steps of providing two Lshaped members (42) each having a horizontal leg (44) and a vertical leg (46) and sealing said horizontal legs to said top portion so that said vertical legs are juxtaposed one another.
30. The method of fabricating and testing a liquid storage tank as set forth in claim 29, characterized by the step of sealing said vertical legs to one another at extended ends (48) of said Lshaped members.
31. The method of fabricating and testing a liquid storage tank as set forth in either claim 29 or 30, characterized by the step of cutting an opening (18) in the top portion of said tank between the vertical legs of said Lmembers and between said sealed ends thereof after said pressurizing step has been completed.
32. The method of fabricating and testing a liquid storage tank as set forth in any of claims 2931, further characterized by the step of providing a releasable closure means (50,51) between said vertical legs for releasably closing said opening.
33. The method of fabricating and testing a liquid storage tank as set forth in any of claims 2932, further characterized by the steps of providing a cover, folding said cover about said vertical legs and releasably attaching said cover to said vertical legs.
34. The method of fabricating and testing a liquid storage tank as set forth in any of claims 2233, characterized in that said tank is pressurized with air and checked for leaks using a soapy solution.
35. The method of fabricating and testing a liquid storage tank as set forth in any of claims 2225 further characterized by the steps of reinforcing the top portion with a flexible support member; and cutting an opening through the flexible support member and top portion after said pressurizing step has been completed.
Description:
COLLAPSIBLE STORAGE TANK FOR LIQUIDS This invention relates to collapsible liquid storage tanks, and in particular, it relates to a frameless collapsible liquid storage tank having a closable opening at the top of the tank It is often desirable to have a container or storage tank capable of holding a liquid such that when there is no liquid in the container, it may be collapsed or folded for ease of transportation and storage. Common applications for an affordable and collapsible storage tank would include construction sites and military camps, wherein there may be no running water readily available. In such circumstances, a collapsible and affordable holding tank may be essential for providing an easy and convenient way to store liquids such as potable drinking water at the site. The water may be trucked in and emptied into the storage tank for use therefrom.

Of course, such sites by nature are temporary. When it is desired to move, it is important to have a storage tank that can be readily emptied, cleaned, quickly disassembled, and efficiently packed for transportation.

An example of an existing storage tank for use as described above is shown in Figures 1 and 2. The hydrostatic pressure of the liquid in such a tank aids in maintaining the container in an upright, noncollapsed position. It is also believed that the frusto-conical shape, wherein the bottom of the container is larger than the top, aids in maintaining the shape and stability of the tank because the liquid contained therein employs an upward pressure on the sidewall and reduces the effect of horizontal vector of the hydrostatic pressure against the sidewall. The construction and use of this storage tank is detailed in the United States Military specification MIL-T-53048C.

It has been found that this prior art tank, although useful, has several drawbacks. First, the tank has an upper rim which houses a flotation member or an inflatable tube. This is required to keep the rim above the water level so as to prevent water from spilling over the rim of the tank as the tank is being filled. The problem is that if the rim includes a flotation member, the flotation member is relatively bulky and takes up extra space during shipping and adds to the expense of the tank and increases time for assembly. Likewise, an inflatable tube is used, it is required to

provide a device for inflating the tube, and a small leak in the inflatable tube may result in loosing all the liquid in the tank since water will flow over the rim of the tank resulting in its collapse if the tube is not inflated.

Another problem, as is obvious from looking at the tank in Figure 1, is that the top is open such that airborne contaminants like dirt, dust, rain, etc. can enter the tank and contaminate the water or other liquid therein. It has been known to provide a cover as shown in Figure 2. The cover typically has straps which may be attached to grommets on the tank. Although such a cover will inhibit some airborne contaminants from entering the tank, it is obvious that this method does not provide a tight closure or seal and that a certain amount of contaminants will still enter the tank.

This is particularly true during times such as high winds or storms when the edges of the cover may be blown upwards.

Still another problem with the prior art tank is that the only way to test the tank for leaks when manufacturing it is to fill the tank with a liquid and inspect for leaks. It would be desirable to provide a method for inspecting the tanks for leaks without first requiring the tank to be filled with liquid.

The above-mentioned problems have been solved by providing a liquid storage tank that is collapsible for ease of transportation when not holding a liquid.

The tank includes a base portion and a top portion. The tank does not require any frame, flotation members, or inflatable tube to hold water.

The tank preferably includes a closable, flexable opening and the top portion is sealed to the base portion.

In one embodiment, the opening is linear and the bottom portion includes a bottom wall and a side wall.

The side wall preferably has a frusto-conical shape and is sealed to the bottom wall.

It is also a feature of the invention that the bottom wall is substantially circular, and the top wall preferably includes two substantially semi-circular sections joined and overlapped along the straight edges to form an overlapped region.

Another aspect of the invention is that the sidewall includes a generally triangular-shaped sections, and the sections are joined to one another at seams. The seams extend in a slightly helical fashion about the tank.

It is a further feature of the invention that the liquid storage tank includes at least one nozzle or fitting in a lower portion of said sidewall for filling and draining said tank.

An additional aspect of the invention is that the opening is located in the overlapped region of the top semi-circular sections for providing reinforcement to the opening.

Also, it is a feature of the invention that the opening includes a slit in the overlapped region and two L-shaped members. Each L member has a horizontal leg and a vertical leg. The vertical legs are adjacent one another with the slit located between them. The horizontal legs are attached to the top portion.

Another feature of the invention is that the vertical legs of the L-shaped members are sealed to one another at extended ends of the members.

Additionally, a feature of the invention is that a portion of the vertical legs between the sealed extended ends includes a releasable closing mechanism for opening and closing the opening. The tank also includes a cover foldable about and releasably attachable to the vertical legs.

A different feature of the invention is that the liquid storage tank may be inverted through the opening for ease in cleaning the tank Another feature of the invention is that the liquid storage tank may be placed on an incline of up to at least 10 degrees with the tank being filled to capacity and wherein no liquid will spill from the opening.

It is an added feature of the invention to provide a method for fabricating and testing a liquid storage tank that includes the steps of providing a fabric reinforced elastomeric material, cutting a bottom wall, a sidewall, and a top wall from said material, sealing the bottom wall to the sidewall, sealing the sidewall together with at least one seam, sealing the top wall to the sidewall, pressurizing said tank and checking the tank for leaks when pressurized.

It is another feature of the invention that the sealing is accomplished using a radio frequency method.

It is also a feature of the invention to include a step of sealing the seams of the tank with a sealant tape.

It is also a feature of the invention to provide a method for fabricating and testing a liquid storage tank that includes the steps of providing reinforcing members on the top wall and cutting a slit in the top wall such that the reinforcing members surround the slit.

Another feature of the invention is to provide a method of fabricating and testing a liquid storage tank that includes the steps of providing a cover, folding the cover about the vertical legs and releasably attaching the cover to the vertical legs.

An additional aspect of the invention is to provide a method of fabricating and testing a liquid storage tank wherein the tank is pressurized with air and checked for leaks using a soapy solution.

The invention will now be described in greater detail with reference to the various drawings, in which: Figure 1 is a perspective view of a prior art open top collapsible tank; Figure 2 is a top view of a prior art cover for the tank of Figure 1 ; Figure 3 is a perspective view of the collapsible liquid storage tank of the present invention filled with a liquid; Figure 4 is a top view of the bottom wall of the tank of Figure 3 prior to assembly; Figure 5 is a laid out top view of the sidewall sections of the tank of Figure 3 prior to assembly to the bottom and top walls; Figure 6 is a top view of the top wall of the tank of Figure 3 prior to assembly into the tank; Figure 7 is a perspective view of the top opening of the tank of Figure 3 shown in the open position;

Figure 8 is a perspective view of the opening of the tank of Figure 3 in the closed position and also showing a cover for covering the opening; and Figure 9 is a cross section of the opening taken along line 9-9 in Figure 8.

Referring now to Figures 1 and 2, an example of a prior art liquid storage tank is generally indicated by 1. The prior art liquid storage tank includes a bottom wall 2, a sidewall 3 and a cover 5. Bottom wall 2 and sidewall 3 are made of fiber reinforced elastomeric material, which may be suitable for storing a potable liquid.

Sidewall 3 has an upper rim 4 that includes a floating or reinforcing member (not shown). In the alternative, upper rim 4 may include an inflatable section such that when tank 1 is filled with a liquid, the inflatable rim floats and rises to prevent the liquid from spilling over rim 4. Nozzles 6 are located in sidewall 3 and can be used for filling or draining the tank. Metal grommets 7 are affixed to sidewall 3 so that cover 5 may be attached to tank 1 by hooking straps 8 on the grommets.

Now referring to Figure 3, the preferred embodiment of a liquid storage tank of the present invention is shown generally as 10. The liquid storage tank 10 includes a base portion generally indicated as 11 including a bottom wall 12 and a sidewall generally indicated by 14. Tank 10 also has a top wall or portion 16 and a linear opening generally indicated as 18. Joining bottom wall 12 to sidewall 14 is a seam 13 and joining sidewall 14 to top wall 16 is a seam 15.

Now referring to Figure 4, a top view of bottom wall 12 is shown prior to incorporating the wall into storage tank 10. Bottom wall 12 includes an outer rim 20, which is incorporated in seam 13 when storage tank 10 is assembled. A flexible handle 22 is attached to and located in approximately the center of the bottom wall.

Referring to Figure 5, a laid-out view of sidewall 14 is depicted showing that the sidewall consists of several generally triangular-shaped sections 24, each of said sections having a convex base edge 26, a concave top edge 28, a first side edge 30 and a second side edge 32. Between adjacent sections 24 of sidewall 14 are seams 33 wherein a first side edge 30 of one section 24 is attached to a second side edge 32 of another section 24. Sidewall 14 also includes at least one nozzle 35. In the preferred embodiment, two nozzles are used, one of each of said nozzles being located on opposite sides of storage tank 10 and towards the bottom of sidewall 14.

The preferred embodiment of top wall 16 is depicted in Figure 6. Top wall 16 includes two semi-circular sections 36 having an overlapped region 38 along the straight edges of said sections. Top wall 16 also includes an outer attachment edge 40 for attaching to sidewall 14 at seam 15.

The details of opening 18 are depicted in Figures 7-9. Opening 18 includes a pair of L-shaped reinforcing members generally indicated as 42, each of said L- shaped members having a horizontal leg 44 and a vertical leg 46. Said L-shaped members are located in a back-to-back manner such that vertical members 46 are adjacent or juxtaposed one another and horizontal legs 44 are attached to top wall 16.

Vertical legs 46 have extended ends 48 where said vertical legs are attached or fixed together. Strips of hook and loop material 50 and 51 are attached at the upper ends of vertical legs 46 such that a strip is mounted on both sides of each vertical leg 46. It should be noted that the strips 50 are mounted on the sides of vertical legs 46 adjacent one another, and therefore would be mating strips such that one strip 50 would consist of loops and the other strip 50 of hooks, thereby enabling opening 18 to be closed and opened. Both of strips 51 consist of loop material. Opening 18 also includes a slit 52 in the overlapped region 38 of top 16 and a pathway 54 defined by the area between adjacent vertical legs 46. Slit 52 and pathway 54 span between sealed extended ends 48.

A cover 56 is provided to cover opening 18. Said cover has a hinge or fold 58 and is foldable about said hinge. On a side of cover 56 beneath the fold 58 is a pair of hook material strips 60 attached thereto.

Having described the component parts of liquid storage tank 10, the assembly of said parts will now be described in further detail. In the preferred embodiment, bottom wall 12, sidewall 14, top wall 16, L-shaped members 42, and cover 56 are all made from a fiber reinforced elastomeric material, which is also suitable for potable liquids. An example of a suitable material is DuPont ElvaloyTM, which is an ethylene-based polymer with reinforced synthetic fibers. Any suitable method known in the art may be used for cutting the component parts of tank 10 from the elastomeric material. Once the parts of storage tank 10 have been cut to size, they are joined and sealed at seams 13,15, and 33 using a heat-sealing technique. Radio frequency welding has been found to provide an economic and sound method of making the

seams; however, other methods which are also well known in the art, such as ultrasonic heating, heating with hot air, electrical resistant heat, or other methods, may be utilized. It should be noted that with the material employed and joining techniques utilized, no adhesive is required for seams 13,15, and 33 but may be used for additional assurance of leak resistance. It has been found that a seam overlap width of approximately 1-2 inches provides sufficient strength and leak resistance.

After heat sealing the seams, all seams may be covered with a strip of nylon or polyester tape (not shown), also in the preferred range of 1-2 inches in width, for providing additional strength and leak resistance to the seams.

Semi-circular sections 36 of top wall 16 are joined in overlap region 38 using the same radio frequency technique or other methods described above for seams 13, 15, and 33. Likewise, horizontal legs 44 of L-members 42 are sealed to top wall 16 at overlap region 38 in a similar manner. Extended ends 48 of vertical legs 46, however, are joined using a gummy resinous material such as a polyurethane. The polyurethane in the preferred embodiment is a two-part mixture containing a resin and hardener, which are well known, and hardens upon mixing of the materials. The resin material is also suitable for contact with potable liquids. Also, hook and latch strips 50 and 51 are attached to vertical legs 46, and hook strips 60 are attached to cover 56 using a heat-activated adhesive which is preapplied to the hook and latch strips by the manufacturer. It should be noted that it is preferable for both of strips 60 to be of hook-type material, thereby rendering that both of strips 51 on the exterior of vertical legs 46 would be of loop material. This configuration allows the longitudinal orientation of cover 56 along opening 18 to be reversed without affecting the ability of the cover to be firmly secured to vertical legs 46. Furthermore, opening 18 is easier to grasp for opening or closing with the loop material on the exterior of vertical legs 46 as opposed to hook material. Although, it should be obvious that strips 60 may consist of loop material and strips 51 may be hook material.

Regarding sections 24 of sidewall 14, it should be understood that the generally triangular shape of said sections results in seams 33 extending at an angle from the vertical or otherwise in a slightly helical fashion about liquid storage tank 10. The preferred angle is 26-30 from the vertical, and it has been found that angling the seams in this manner increases the rigidity and stability of the tank, especially

when the tank is placed on an inclined surface. When sealed together, sections 24 form a structure having a generally frusto-conical shape.

Now referring to handle 22, the handle is preferably made from the same material as the body of the tank or another fabric which is suitable with a potable liquid. The handle has ends that are sewn or glued to a larger piece of ElvaloyTM material, which in turn is heat-sealed or glued to bottom wall 12.

Regarding the attachment of nozzles 35 to sidewall 14, the nozzles are of a rigid construction, such as metal or plastic, and are bolted to a flange (not shown) on the interior of the tank in a manner that is well known in the art. The nozzles are sealed against leaks using a gasket (not shown). Obviously, sidewall 14 will include holes for the bolts (not shown) and a hole to allow liquid to pass through nozzle 35.

Each nozzle 35 is also equipped with a removable cap (not shown) which is attached to the nozzle with threads or a quick connect. The threads or quick connect on the nozzle can also be used to facilitate a hose attachment to fill or drain said tank A significant advantage obtained by the preferred assembly of liquid storage tank 10 is that it allows for pressure testing for leaks. Accordingly, slit 52 in top 16 is not cut until after the pressure testing has been completed. Upon completion of all previously described seams and taped reinforcement, the tank is inflated with air that is pumped in through one of the nozzles 35 until a positive pressure is created internal to the tank. Once pressurized, all seams and material of the tank may be checked for leaks using a soapy solution. Any leaks will create a bubbling effect in the solution.

Any leaks in the seams may be reheated and sealed or patched with a piece of material of the same type as the balance of said tank. A patch may be heat sealed or adhesively attached. Once the tank has successfully completed pressure testing, slit 54 may be cut by spreading apart vertical legs 46 of L members 42 and accessing and cutting top 16 in the overlapped region 38 through the pulled open pathway 54. It should be evident to one skilled in the art that the above-described assembly steps and testing offers a significant advantage over the prior art tank 1 in that the only way to test the prior art tank for leaks is by filling the tank with a liquid.

Having described the component parts and assembly of liquid storage tank 10, the operation of unit will now be described. As evident from the above description, storage tank 10 has no rigid frame or rigid/floating reinforcing members at the top or

the bottom of the sidewalls. The only rigid portion of the tank being nozzles 35. This means that storage tank 10 can be folded very compactly for storage and transportation purposes. In addition, the design provides a tank that is relatively light in weight, which is another important advantage in the transportation thereof.

When it is desired to fill storage tank 10, it is laid out with bottom wall 12 on the surface, which will support the tank. The tank can then be filled with a hose 62 attached to one of the nozzles 35 or opening 18 may be opened so that the tank may be filled from the top. It should be noted that the design of tank 10 is such that when filled to capacity, the liquid column does not rise completely to the top of wall 14; therefore, the upper end of sidewall 14 and top 16 is not stressed by the liquid and thereby rests freely and loosely gathered on the surface of the liquid. The liquid may also be removed from the tank through opening 18 or out of one of the nozzles 35.

Another advantage of the present invention is that as opening 18 and top 16 are made of flexible elastomeric material, vertical legs 46 may be pulled apart to greatly increase the width of pathway 54 and slit 52. The flexible nature of the elastomeric material allows opening 18 to be spread sufficiently that it is easy to draw liquid therefrom. It should also be appreciated that overlapped region 38 and horizontal legs 44, as well as sealed ends 48 of vertical legs 46 serve to reinforce top wall 16 so as to prevent slit 52 from propagating beyond the desired length.

It should be apparent from the above description of tank 10 that the only pathways for liquid to escape from the tank is either through nozzles 35 or through slit 52 and pathway 54 out over the top of vertical legs 46. The design of the present invention, however, is such that opening 18 may be open as shown in Figure 7 with the tank filled to capacity and no liquid will spill over the top of vertical edges 46. In addition, the tank may be placed on a slope of up to 10 degrees without any spillage through opening 18. It should be noted, however, that if storage tank 10 is to be utilized on a sloped surface, linear opening 18 should be placed transverse to the incline as this assures that the lowest height of pathway 54 from which the liquid would spill is at the highest possible elevation. Furthermore, the loosely gathered material as described earlier at the top of tank 10 allows additional liquid to accumulate on the portion of tank 10 that would be on the downward side of the slope so that the liquid level will not rise above the top of pathway 54.

It should also be obvious that the liquid contained in tank 10 is shielded from environmental contaminants such as rain, dirt, dust, and air-borne debris by fastening hook and loop strips 50 in pathway 54 and additional protection may be obtained by folding cover 56 about vertical legs 46 and attaching hook and loop strips 51 and 60 to one another.

When it is desired to clean the interior portion of tank 10, any remaining liquid is removed, cover 56 is removed and opening 18 is opened as described above.

Handle 22 can then be reached through opening 18 and pulled such that the tank can be inverted through slit 52 and pathway 54 so that the interior of tank 10 would now be towards the exterior. In this manner, the tank may be wiped down, disinfected, and allowed to thoroughly dry before inverting the tank to the original position for use again.

It will be obvious to one skilled in the art that certain changes may be made to the above-preferred embodiment without departing from the scope of the invention.

For instance, although the preferred embodiment has a top wall constructed from two semi-circular pieces thus having an overlapped region, the top could be constructed from a singular piece or more than two pieces. In addition, the reinforcement on the top to prevent slit 52 from propagating could consist of sections of additional layers of material adhered on either side of top 16. Additional reinforcing material could also be overlaid horizontal legs 44. Furthermore, while the opening is shown to follow a straight line, other designs could be utilized with the present invention such as an X-shaped opening, an S-shaped opening or T-shaped opening. Also, other shapes of opening supports may be substituted for the L-shaped members used in the embodiment shown.

It should also be appreciated that, although the preferred embodiment utilizes five or six sidewall sections 24, either more or fewer sections could be used. As a matter of fact, sidewall 14 can be made from a singular piece cut to size and having only one vertical seam. Of course, the angle of the seams from the vertical may also be varied. Also, although one handle 22 is shown located in the center of bottom wall 12, additional handles may be used and located other than centrally to the bottom.

It should also be recognized that, although the preferred embodiment utilizes a hook and loop fastening material for closing the opening 18 and attaching cover 56,

any suitable fastener method may be employed, such as snaps, zippers, string ties, clips, etc.

While the invention has been taught with specific reference to these embodiments, someone skilled in the art will recognize that other changes can be made in form and detail without departing from the spirit and the scope of the invention. The described embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the following claims rather than by the description.