GB2477266A

GB2477266A - Storage Tank for Liquids having No Internal Supports

Info

Publication number: GB2477266A
Application number: GB201000968A
Authority: GB
Inventors: Simon Robert Procter
Original assignee: Joseph Ash Ltd
Current assignee: Joseph Ash Ltd
Priority date: 2010-01-21
Filing date: 2010-01-21
Publication date: 2011-08-03
Also published as: GB201000968D0

Abstract

A liquid storage vessel has inner tank 2 and outer container 3 each having at least three side walls 21-24, 31-34, a base 25, 35 and a top 4, the base and sides of the tank 2 being spaced from those of the container 3, supported by joining means 27, the top having stiffening means 50, the joining and stiffening means forming continuous structures around the container i.e. along the walls, base and top of the tank. The spacing of the base and walls may provide a reservoir 7 having at least 10 percent of the capacity of the inner tank 2, connected to the tank by overflow pipe 8 and having drain pipe 9. The joining means may be steel "I" beams and the stiffening means may be flat steel plates. Holes 28 in the joining means may provide air through flow. The base of the tank may be sloped (figures 3, 5). The vessel may be placed on steel supporting sections 6. The lack of supports inside the tank allows easy access and cleaning by machinery.

Description

STORAGE VESSELS FOR LIQUIDS

The present invention relates to storage vessels for liquids in which the main storage tank is surrounded by an outer container capable of retaining any overfill or leakage.

Storage tanks for liquids such as fuel oils and chemicals have in the past been contained in catchpits to retain any leakage or spillage from the tanks. More recently double walled storage tanks have been developed with a space between the inner and outer walls acting to retain overfill or leakage. Convenient means are provided to withdraw liquid from the space within the inner and outer walls as and when necessary.

There is a need, which is increasing, for storage tanks to be cleaned and inspected on a regular basis. This is particularly the case where the liquid being stored is a bio-fuel. Storage of bio-fuels leads to bacterial growth forming, particularly on the bottom of the storage tank, which must be regularly removed. At present to meet certain British Standards flat sided tanks have to have internal stays supporting the base and walls and therefore cleaning is generally a manual operation requiring man entry into the enclosed space of the tank. However, this leads to health and safety concerns.

The present invention comprises a storage vessel comprising a tank and an outer container, the tank and the outer container each having three or more side walls, a base and a top; the tank is positioned within the outer container; the tank walls and base are spaced apart from the walls and base of the outer container and each wall of the outer container is secured to a corresponding wall of the tank by one or more joining means co-extensive with one or both of the width and height of the walls of the tank or outer container, there are provided one or more joining means extending between the base of the outer container and the base of the tank co-extensive with one or both of the width and length of the base of the tank or the base of the outer container; the top is provided with one or more stiffening means co-extensive with one or both of the width and length of the top of the tank; and the joining means and the stiffening means are arranged to form one or more continuous structures extending along the walls, base and top of the tank.

In one embodiment the tank and outer container have the same number of sides. The tank and outer container may be the same shape.

In one embodiment the top of the tank may be provided with one or more stiffening means in the form of stiffening baffles co-extensive with one or both of the length and width of the top of the tank.

In a further embodiment the top of the outer container also forms the top of the tank. The top of the tank may be provided with one or more stiffening means in the form of stiffening baffles co-extensive with the one or both of the length and width of the top of the tank.

In a yet further embodiment the top of the tank may be in contact with the top of the outer container and may be secured directly thereto such that the stiffening means of the top of the tank is the top of the outer container. The top of the tank may in addition be provided with one or more stiffening means in the form of stiffening baffles co-extensive with one or both of the length and width of the top of the tank.

In one embodiment the tank has four sides, for example the tank is rectangular or square. In one embodiment the outer container also has four sides, for example the outer container is rectangular or square. The tank and outer container may be of the same shape, for example they may both be rectangular or square.

In one embodiment the base of the tank has one or more sloping sections.

This allows improved drainage of the tank.

In one embodiment the tank has two or more discrete compartments. One or more dividing walls may be provided separating the compartments.

The or each dividing wall may extend from the base of the tank, preferably to the top of the tank. The or each dividing wall may be provided with one or more stiffening baffles co-extensive with one or both of the length and width of the wall. The or each stiffening baffle may be positioned in line with a joining means between the tank and the outer container.

In one embodiment the tank has no internal stays or structural supports for the walls and base. This allows for greater, or even total, automation of inspection and cleaning of the tanks.

The or each joining means may be secured to the walls of one or both of the tank and the outer container by any suitable means, such as by welding.

The or each joining means extending between the base of the outer container and the base of the tank may be secured to the base of the tank, or the base of the outer container or both. The or each joining means may be secured to the one or both of the base of the tank and the base of the outer container by welding.

The or each joining means is preferably made from a material suitable to provide strength, support and stability to the tank, for example steel. The or each joining means may be a beam with any suitable cross section, for example an "I" cross section, a "C" cross section or an "L" cross section. The or each joining means may alternatively be a suitable hollow section beam. In one embodiment the or each joining means is a beam of "I" cross section. One or more of the joining means may be provided with one or more holes to allow air through flow.

The or each stiffening means may be provided on the inside or the outside surface of the top of the tank.

The or each stiffening means may be a stiffening baffle and may be welded to the top of the tank. Alternatively the or each stiffening baffle may be formed integrally with the top of the tank.

In one embodiment the or each stiffening baffle is a flat bar. The stiffening baffle is preferably positioned perpendicular to the dividing wall or top of the tank. The or each stiffening baffle may be made from any suitable material, for example steel.

The joining means and/or stiffening baffles may be joined to each other where they meet by any suitable means, for example welding. The joining means and/or stiffening baffles may be joined directly to each other where they meet. Alternatively a joining means may be joined to one side of a wall of the tank and a stiffening means may be joined to the other side of the wall.

One or more of the outer container, the tank and any dividing walls may be made from any suitable material, for example carbon steel or stainless steel. All or part of the tank may be a double skinned tank. All or part of the outer container may be double skinned.

The thickness of the walls of the outer container and the tank and any dividing walls may be 2 to 10mm, for example 3 to 8mm or 3 to 6mm.

The area between the tank and the outer container forms a reservoir to hold any overflow or leakage from the tank. The reservoir may conveniently amount to about 10% of the volume of the storage tank.

The vessel may include an inspection and/or access hole to the tank. The hole may be provided with a cover. There may be provided a means, such as a sighting glass or suitable sensor, for observing the presence and/or amount of liquid in the reservoir. There may be provided a suitable warning system in relation to any overfilling or overflow of the tank. There may also be provided means extending into the reservoir for drawing or draining off any liquid collecting therein. Discharge and drain means extending through the outer container and communicating with the tank may also be provided. There may be provided means to fill the tank.

There may also be included in the tank heating elements, for example heating coils, vents and pipes to allow transfer of vapours or liquid from the tank to the reservoir.

The tank and outer container may be of any suitable size. The number of joining means and/or stiffening means, and therefore the number of continuous structures extending along the walls, base and top of the tank, may be any suitable number. The number of joining means and/or stiffening means, and therefore the number of continuous structures extending along the walls, base and top of the tank may vary with the size of the tank and/or the outer container. This is also true for the level of stiffening and strengthening provided which can be varied, for example depending on the size of the tank, by means such as choice of section and material for the joining and/or stiffening means.

The vessel of the present invention has the advantage of providing a tank that has no internal structures, such as stays, that will hinder or prevent automated cleaning and inspection.

Embodiments of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 is a cross sectional view along the longitudinal axis of a rectangular storage vessel in accordance with a first embodiment of the present invention; Figure 2 is a plan view from above of the vessel of Figure 1; Figure 3 is a cross sectional view along the longitudinal axis of a rectangular storage vessel in accordance with a second embodiment of the present invention; Figure 4 is a plan view from above of the vessel of Figure 3; Figure 5 is a cross sectional view along the longitudinal axis of a rectangular storage vessel in accordance with a third embodiment of the present invention; and Figure 6 is a plan view from above of the vessel of Figure 5.

Figures 1 and 2 show a rectangular storage vessel, generally indicated at 1, comprising a tank 2 having walls 21, 22, 23 and 24 and a base 25, an outer container 3 having walls 31, 32, 33, 34 and a base 35. and a top 4 shared by both the tank 2 and the outer container 3.

In use the vessel may be located on a plurality of steel supporting sections 6.

Walls 31, 32, 33 and 34 of the outer container 3 are spaced apart from the corresponding walls 21, 22, 23 and 24 of the tank 2. Base 25 of tank 2 is spaced apart from base 35 of the outer container 3. The distance between walls 31, 32, 33 and 34, and base 35, of the outer container 3 and corresponding walls 21, 22, 23 and 24, and base 25, of the tank 2 is sufficient to provide a containment zone (or reservoir) 7 equal in capacity to at least 10% of the capacity of the tank 2.

As indicated above top 4 is shared by the tank 2 and outer container 3 and is welded to free upper edge portions of all four walls 31, 32, 33 and 34 of the outer container 3 to provide a liquid tight seal. The walls 21, 22, 23 and 24 of tank 2 extend up to and touch top 4 and are also welded thereto to provide a liquid tight seal.

There are provided extending between, and secured to where appropriate, adjacent walls and bases of the tank 2 and outer container 3 a number of joining means 27. In the embodiment shown in Figures 1 and 2 the joining means 27 are steel beams of an "I" cross section.

In the embodiment shown in Figures 1 and 2 a number of sets of three I-beams are provided. Three sets of I-beams (A, B, C shown in Figure 2) are arranged such that in each set one beam will extend between walls 21 and 31 from the top 4 to the base 35 of the outer container. One beam will extend between walls 23 and 33, again extending from the top 4 to the base 35 of the outer container. Another beam will extend between bases 25 and 35, co-extensive with the base 25 of the tank 2. In each set the I-beams are secured together where they meet by welding. The sets of beams form three structures each extending along two sides and the base of the tank 2 transverse to the longitudinal axis of the tank.

Two sets of I-beams (D, E shown in Figure 2) are arranged such that in each set one beam will extend between walls 22 and 32, from the top 4 to the base 35 of the outer container. One beam will extend between walls 24 and 34, from the top 4 to the base 35 of the outer container and another beam will extend between bases 25 and 35, co-extensive with the base 25 of the tank 2. The sets of beams form two structures each extending around two sides and the base of the tank 2 parallel to the longitudinal axis of the tank.

The beams are secured by welding to the side walls 21, 21, 23, 24 of the tank 2 and the side walls 31, 32, 33, 34 of the outer container 3 and also to the base 25. There is no need to secure the beams to the base 35 as the weight of the tank with hold the beams against this surface.

The top 4 of the vessel, where it forms the top of the tank 2, will be provided with an arrangement of internal stiffening baffles 50a, SOb welded to the underside of the top 4. The stiffening baffles 50a, SOb are flat steel plates. Two internal stiffening baffles 50a are positioned one in line with each of the sets of I-beams A and C to form two continuous structures extending around the tank 2, transverse to the longitudinal axis of the tank 2. Four internal stiffening baffles 50b are provided with two positioned in line with each of the sets of I-beams D and E and extending between the walls 22 and 24 of the tank 2 and the internal baffles 50a.

The joining means 2? can include holes 28 for air through flow.

The final result is a unitary structure extending between the outer container 3 and the tank 2 and providing a structure giving support, strength and stability to the tank 2 and eliminating the need for internal stays or support structures of any sort to be provided in the tank 2. The lack of internal support structures will allow more automated inspection and cleaning of the tank.

The vessel shown in Figures 1 and 2 has a dividing wall 26 provided in the tank 2 to give rise to two compartments within the tank. The dividing wall 26 extends between and touches top 4 and base 25 and is welded to each, and in addition to the side walls 21 and 23, to provide a liquid tight seal. The dividing wall is provided with one or more internal stiffening baffles, extending from the base 25 to the top 4 of the tank. The stiffening baffles are flat plates 29 extending transverse to the dividing wall.

The dividing wall 26 need not be positioned in line with any of the sets of I-beams extending around the tank 2. The position of the dividing wall 26 can be varied such that any practical volumetric split required by the customer or designer can be achieved.

An overflow coupling 8 is provided in top 4 extending between tank 2 and containment zone 7. A drain pipe 9 for the containment zone 7 extends upwardly from the bottom of containment zone 7 through the top 4 to the outside of the vessel and includes a connection point 9a at the upper end thereof to permit attachment of appropriate apparatus to allow liquid to be withdrawn from zone 7.

A low level gravity feed outlet pipe 60 is provided extending from the tank 2, close to the base 25, through the containment zone 7 and outer container 3 to allow the contents of the tank 2 to be withdrawn as required under the force of gravity. An emergency shut off valve 47 is provided at a suitable point along the outlet pipe 60 inside the tank 2.

There is provided an actuator shaft 10 to allow remote operation of the emergency shut off valve 47. The shaft 10 is provided with a "T" bar 12 that is turned to operate the shut off valve 47 and a cap 13 to cover the "T" bar.

A top suction outlet 80 is also provided extending through the top 4 into the tank 2 and includes a connection point 80a at an upper end thereof to permit attachment of appropriate apparatus to allow liquid to be withdrawn from tank 2. This provides an alternative way to remove the contents of the tank but requires the use of suction apparatus (not shown).

A drain pipe 70 for the tank 2 extends upwardly from the bottom of tank 2 through the top 4 to the outside of the vessel and includes a connection point 7Oa at an upper end thereof to permit attachment of appropriate apparatus to allow liquid to be withdrawn from tank 2.

Two inspection/man access holes (not shown) with covers 16 are provided in the top 4 of the vessel 1, one to allow access to each compartment of the tank 2. Also provided in top 4 is a vent 18 communicating with containment zone 7. The tank 2 is vented to the containment zone 7 via coupling 8.

One or more appropriate sensors are provided to monitor the level of any liquid in the containment zone 7. The or each sensor is positioned at the sensor connection point 75 and can be a mechanical or electrical sensor.

In the embodiment shown the tank 2 is provided with a heating coil 19 through which hot water can be passed.

In use any leakage from the inner tank 2 drains into the containment zone 7. Any overflow from the top of the inner tank 2 flows into the containment zone 7 via coupling 8. The drain pipe 9 for the containment zone 7 allows removal of liquid from the containment zone, which can be drawn off through connection 9a.

In Figures 3 and 4 like numbers indicate like parts. Figures 3 and 4 show a vessel 100 comprising a tank 20 and an outer container 3. In Figures 3 and 4 the tank 20 has only a single compartment, therefore no dividing wall 26 is provided. However, a further internal stiffening baffle 95 is provided on the top 4, positioned in line with the set of I beams "B".

In the tank 20 there is provided a base 45 that slopes downwards away from side walls 21, 22, 23 and 24 to form a tented shape and has lowest point, sump 30, located in the approximate centre of the base. A drainage pipe 3? is provided extending upwards from the sump 30 through the top 4 to the outside of the vessel. Drainage pipe 37 has a connecting point 37a at the upper end thereof to allow connection to apparatus suitable to allow withdrawal of the liquid.

Stiffening sections 46 are provided extending between the base 45 of the tank 20 and the base 35 of the outer container 3 and are suitably shaped to accommodate the tented shape of the base 45. The stiffening sections are flat steel plates and are positioned such that they provide continuity with the joining means extending between the side walls of the tank and outer container and the internal baffles of the top.

In Figures 3 and 4 there is shown a fill pipe 90 provided with a connection point 90a for connection to a tanker delivery hose and an end 90b opening into tank 2. The fill pipe extends from end 90b opening into the tank 2, through the top 4 and then extends parallel to the top 4 and the side wall 32 of the vessel terminating with connection point 90a provided at a suitable height for access by a tanker.

The fill pipe 90 shown in Figures 3 and 4, or a similar arrangement, would be present in all tanks even if not shown and if a tank was divided into compartments a fill pipe may be provided for each compartment. (Is this correct -the fill pipe is not shown in Figures 1 and 2.) In Figure 4 there is shown a connection point 76 for a suitable overflow alarm and a connection point 77 for a contents gauge for the tank 20.

These connection points may be provided in any of the vessels of the invention.

In Figures 5 and 6 like numbers indicate like parts. Figures 5 and 6 show a vessel 101 comprising a tank 200 and an outer container 3. In Figures 5 and 6 the tank 200 has only a single compartment, therefore no dividing wall 26 is provided. However, a further internal stiffening baffle 95 is provided on the top 4, positioned in line with the set of I beams "B".

In the tank 200 there is provided a base 55 that slopes downwards away from side wall 24 and has lowest point 56 located where it meets side wall 22. A drainage pipe 51 is provided extending upwards from the lowest point of the tank 200, where the base 55 meets the wall 22.

Drainage pipe 51 is provided with a connection point 51a at its upper end to allow connection to apparatus suitable to allow withdrawal of liquid from the tank 200.

In use each of the vessels described can store liquids and when the vessels requires cleaning or inspection the liquid can be withdrawn and the tank 2 can be inspected or cleaned in part or completely using appropriate machinery rather than manually. This is because the tank does not contain any internal stays or supporting structures to hinder access by machinery.

Claims

CLAIMS1. A storage vessel comprising a tank and an outer container, the tank and the outer container each having three or more side walls, a base and a top; the tank is positioned within the outer container; the tank walls and base are spaced apart from the walls and base of the outer container and each wall of the outer container is secured to a corresponding wall of the tank by one or more joining means co-extensive with one or both of the width and height of the walls of the tank or outer container, there are provided one or more joining means extending between the base of the outer container and the base of the tank co-extensive with one or both of the width and length of the base of the tank or the base of the outer container; the top is provided with one or more stiffening means co-extensive with one or both of the width and length of the top of the tank; and the joining means and the stiffening means are arranged to form one or more continuous structures extending along the walls, base and top of the tank.

2. The storage vessel of claim 1, in which the tank and outer container have the same number of sides.

3. The storage vessel of claim 1 or claim 2, in which the top of the tank is provided with one or more stiffening means in the form of stiffening baffles co-extensive with one or both of the length and width of the top of the tank.

4. The storage vessel of any preceding claim, in which the top of the outer container also forms the top of the tank.

5. The storage vessel of any preceding claim, in which the top of the tank is in contact with the top of the outer container and is secured directly thereto such that the stiffening means of the top of the tank is the top of the outer container.

6. The storage vessel of any preceding claim, in which the tank has two or more discrete compartments, with one or more dividing walls being provided separating the compartments.

7. The storage vessel of claim 6, in which the or each dividing wall extends from the base of the tank, preferably to the top of the tank.

8. The storage vessel of claim 6 or claim 7, in which the or each dividing wall is provided with one or more stiffening baffles co-extensive with one or both of the length and width of the wall.

9. The storage vessel of claim 8, in which the or each stiffening baffle is positioned in line with a joining means between the tank and the outer container.

10. The storage vessel of any preceding claim, in which the tank has no internal stays or structural supports for the walls and base.

11. The storage vessel of any preceding claim, in which the or each joining means extending between the base of the outer container and the base of the tank is secured to the base of the tank, or the base of the outer container or both.

12. The storage vessel of any preceding claim, in which the or each stiffening means is a stiffening baffle being a flat bar, preferably positioned perpendicular to the dividing wall or top of the tank.

13. The storage vessel of any preceding claim, in which the area between the tank and the outer container forms a reservoir to hold any overflow or leakage from the tank.

14. The storage vessel of claim 13, in which the reservoir amounts to about 10% of the volume of the storage tank.

15. The storage vessel of claim 13 or claim 14, in which the vessel is provided with a means, such as a sighting glass or suitable sensor, for observing the presence and/or amount of liquid in the reservoir.

16. The storage vessel of any of claims 13 to 15, provided with means extending into the reservoir for drawing or draining off any liquid collecting therein. r

1?. The storage vessel of any preceding claim, having in which the tank has no internal structures, such as stays, that will hinder or prevent automated cleaning and inspection.

18. A storage vessel of substantially as described herein with reference to and as illustrated in the accompanying drawings.