GB1592247A

GB1592247A - Liquid storage tanks

Info

Publication number: GB1592247A
Application number: GB45171/76A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-10-19
Filing date: 1977-10-19
Publication date: 1981-07-01

Description

(54) IMPROVED LIQUID STORAGE TANKS (71) I, NORMAN FRANK DEWEY, of Vine Cottage, Urchinwood, Congresbury, Bristol, a British-subject, formerly of Orchard Rise, School Road, Wrington, Bristol, Avon, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to storage tanks for liquids, for example water.

It is economically desirable to manufacture water storage tanks with walls which are as thin as possible. However, if the walls are made too thin, they may not be sufficiently strong, so that when the tank is full of water the walls may bulge outwardly and there may be a danger of rupture. A strong unitary tank may be made from glass fibre reinforced resin material, but bulging of the walls may still occur, and even though this may not be dangerous in fact, it looks unsafe to the user. Internal bracing may be used in very large sectional tanks, but with somewhat smaller tanks it is convenient to make them as unitary structures, so that internal bracing would prevent nesting of the tanks for storage and transit.

According to the present invention there is provided a liquid storage tank, having a bottom and walls upstanding therefrom, the walls being upwardly divergent so that similar containers can be nested together, stiffening ribs projecting inwardly from at least some of the walls so that corresponding recesses are formed in the opposite surfaces of the walls, the ribs extending from the bottom of the tank and tapering upwardly and having a tapering horizontal crosssection, whereby when two tanks are nested the ribs of one tank nest in the recesses of the ribs of the other tank, the ridge of each rib extending in a substantially straight inclined line between the bottom and a side wall to provide a tensile bracing connection between them.

Preferably denesting recesses are formed in the bottom of the tank, the disposition of the recesses being non-symmetrical with respect to a vertical median plane through the tank, whereby when two similar tanks are nested if one tank has been rotated horizontally through 1800 with respect to the other tank the bottom of the tank above will rest on the internal shoulders formed b.y the denesting ledges of the tank below.

The tank is preferably of integral construction, moulded from a fibre reinforced settable material, such as glass fibre reinforced resin or a glass fibre reinforced cementitious composition.

One preferred embodiment of the invention will now be described by way of example with reference to the. drawings accompanying the Provisional Specification, wherein: Figure 1 is a perspective view from above of the tank, Figure 2 is a perspective view of the tank from below, Figure 3 is a transverse cross-section through the tank, and Figure 4 is a longitudinal cross-section through the tank showing a suitable form of tank cover in place.

Referring to the drawings, the tank is an integrally moulded structure of glass fibre reinforced resin material. It is open-topped and has a base 10 which is generally rectangular. Integral walls 12a, 12b extend upwardly from the periphery of the base and slope outwardly towards the top in order that a number of similar tanks may nest inside each other for storage and transport.

About halfway up the walls is a horizontal inwardly directed ledge 14 with a corresponding external shoulder 16, which provides a degree of stiffening against vertical flexing. A continuous out-turned flange 13 is provided around the top of the tank.

Internal strengthening ribs 18 are formed two in each of the two longer walls 12a and one in each of the shorter walls 12b. These ribs are moulded in the walls and base and have a generally V-shaped horizontal crosssection, and thus each rib has a corresponding recess 20 on the outer surface of the tank. Moreover, the cross-section of reach rib reduces to an apex near the upper edge of the wall, and thus the recesses 20 form recessed regions 22 (see Figure 2) around the edge of the generally rectangular base 10.

The ribs and corresponding recesses are of such a shape that when two of the tanks are nested they nest together with the ribs of the lower tank received in the recesses of the upper tank.

The four lower corners of the tank have additional rectangular recesses 24, 26, which provide corresponding shoulders inside the tank. At one end of the tank, the recesses 24 are formed with their longest edges in the longer walls 12a, whilst at the other end the recesses 26 have their longest edges in the shorter walls 12b. These recesses 24, 26 are thus arranged such that when similar tanks are nested one tank is rotated through 1800 with respect to the other, so that the recesses 24 of one tank overlie the nonmating shoulders 26 of the other tank, and vice versa, so that the base 10 of the upper tank will rest on those shoulders of the lower tank, giving a denesting clearance between the two tanks.

A separate cover panel may be removably or permanently secured to the flange 13 at the top of the tank. This panel can also be of glass fibre reinforced resin material, and provides cross bracing for the tank walls at the top, as well as providing a top closure.

Figure 4 shows a cover comprising a fixed panel 30 extending over two thirds of the length of the tank, and a removable panel 32 extending over the other one third. The fixed panel can be bolted to the flange 13, for example at the five points 34 corresponding to the ribs 18. It could be sealed to the tlange if desired. The removable panel can rest loosely on top of the tank, optionally with locating elements to keep it in place.

WHAT I CLAIM IS: l. A liquid storage tank, having a bot- tom and walls upstanding therefrom, the walls being upwardly divergent so that similar containers can be nested together, stiffening ribs projecting inwardly from at least some of the walls so that corresponding recesses are formed in the opposite surfaces of the walls, the ribs extending from the bottom of the tank and tapering upwardly and having a tapering horizontal crosssection, whereby when two tanks are nested the ribs of one tank nest in the recesses of the ribs of the other tank. the ridge of each rib extending in a substantially straight inclined line between the bottom and a side wall to provide a tensile bracing connections between them.

2. A liquid storage tank according to claim 1 wherein denesting recesses are formed in the bottom of the tank, the disposition of the recesses being nonsymmetrical with respect to a vertical median plane through the tank, whereby when two similar tanks are nested if one tank has been rotated horizontally through 1800 with respect to the other tank the bottom of the tank above will rest on the internal shoulders formed by the denesting ledges of the tank below.

3. A liquid storage tank according to claim 1 or claim 2 wherein the ribs reduce to an apex near the upper edge of the tank.

4. A liquid storage tank according to any one of the preceding claims wherein said ribs are provided on all of the walls.

5. A liquid storage tank according to any one of the preceding claims wherein the walls are stepped outwardly intermediate the bottom and the upper edge of the tank.

6. A liquid storage tank according to any one of the preceding claims wherein a continuous out-turned flange is provided around the top of the tank.

7. A liquid storage tank according to claim 6 wherein a cover panel is secured to the flange at the top of the tank.

8. A liquid storage tank according to claim 7 wherein the cover panel extends over a major part of the top of the tank, a separate removable panel covering the remaining area to provide access to the interior of the tank.

9. A liquid storage tank substantially as described herein with reference to the drawings accompanying the Provisional Specification.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

Internal strengthening ribs 18 are formed two in each of the two longer walls 12a and one in each of the shorter walls 12b. These ribs are moulded in the walls and base and have a generally V-shaped horizontal crosssection, and thus each rib has a corresponding recess 20 on the outer surface of the tank. Moreover, the cross-section of reach rib reduces to an apex near the upper edge of the wall, and thus the recesses 20 form recessed regions 22 (see Figure 2) around the edge of the generally rectangular base 10.

The ribs and corresponding recesses are of such a shape that when two of the tanks are nested they nest together with the ribs of the lower tank received in the recesses of the upper tank.

The four lower corners of the tank have additional rectangular recesses 24, 26, which provide corresponding shoulders inside the tank. At one end of the tank, the recesses 24 are formed with their longest edges in the longer walls 12a, whilst at the other end the recesses 26 have their longest edges in the shorter walls 12b. These recesses 24, 26 are thus arranged such that when similar tanks are nested one tank is rotated through 1800 with respect to the other, so that the recesses 24 of one tank overlie the nonmating shoulders 26 of the other tank, and vice versa, so that the base 10 of the upper tank will rest on those shoulders of the lower tank, giving a denesting clearance between the two tanks.

A separate cover panel may be removably or permanently secured to the flange 13 at the top of the tank. This panel can also be of glass fibre reinforced resin material, and provides cross bracing for the tank walls at the top, as well as providing a top closure.

Figure 4 shows a cover comprising a fixed panel 30 extending over two thirds of the length of the tank, and a removable panel 32 extending over the other one third. The fixed panel can be bolted to the flange 13, for example at the five points 34 corresponding to the ribs 18. It could be sealed to the tlange if desired. The removable panel can rest loosely on top of the tank, optionally with locating elements to keep it in place.

WHAT I CLAIM IS: l. A liquid storage tank, having a bot- tom and walls upstanding therefrom, the walls being upwardly divergent so that similar containers can be nested together, stiffening ribs projecting inwardly from at least some of the walls so that corresponding recesses are formed in the opposite surfaces of the walls, the ribs extending from the bottom of the tank and tapering upwardly and having a tapering horizontal crosssection, whereby when two tanks are nested the ribs of one tank nest in the recesses of the ribs of the other tank. the ridge of each rib extending in a substantially straight inclined line between the bottom and a side wall to provide a tensile bracing connections between them.
2. A liquid storage tank according to claim 1 wherein denesting recesses are formed in the bottom of the tank, the disposition of the recesses being nonsymmetrical with respect to a vertical median plane through the tank, whereby when two similar tanks are nested if one tank has been rotated horizontally through 1800 with respect to the other tank the bottom of the tank above will rest on the internal shoulders formed by the denesting ledges of the tank below.
3. A liquid storage tank according to claim 1 or claim 2 wherein the ribs reduce to an apex near the upper edge of the tank.
4. A liquid storage tank according to any one of the preceding claims wherein said ribs are provided on all of the walls.
5. A liquid storage tank according to any one of the preceding claims wherein the walls are stepped outwardly intermediate the bottom and the upper edge of the tank.
6. A liquid storage tank according to any one of the preceding claims wherein a continuous out-turned flange is provided around the top of the tank.
7. A liquid storage tank according to claim 6 wherein a cover panel is secured to the flange at the top of the tank.
8. A liquid storage tank according to claim 7 wherein the cover panel extends over a major part of the top of the tank, a separate removable panel covering the remaining area to provide access to the interior of the tank.
9. A liquid storage tank substantially as described herein with reference to the drawings accompanying the Provisional Specification.