Leak Preventing Device and Tank for Transporting Liquid With such a Device

Abstract

A leak preventing device (1) for preventing liquid from leaking out of a damaged tank (2), the device comprising:—a floating body (4) capable of floating at the surface (3) of the liquid in the tank; and—a flexible hose (5), the first end of the hose being fixed to the floating body and the hose being fixed to a wall of the tank at a point of attachment (8) at a distance from said first end, wherein the hose extends freely inside the tank between the floating body and said point of attachment and wherein the second end of the hose is connectable to a suction side of a vacuum pump(9) so as to allow gas to be drawn off via the hose from a gas-filled space (10) in the tank above the surface of the liquid in order to produce an under pressure in said space. The invention also relates to a tank for transporting liquid provided with such a device.

Description

FIELD OF THE INVENTION AND PRIOR ART

The present invention relates to a leak preventing device according to the preamble of claim 1 for preventing liquid from leaking out of a damaged tank. The invention also relates to a tank for transporting liquid provided with such a device.

Liquid fuel and other types of liquids may be transported and stored in tanks of various types. If such a tank is damaged, for instance due to an accident or wear, the liquid in the tank may leak to the surrounding environment, which may cause a lot of problem, for instance in the form of material damages, environmental pollution and health and safety hazards for people in the vicinity of the leaking tank. It is previously known, for instance from GB 1 020 581 A and DE 1 525 465 B, that liquid may be prevented from leaking out through a leak below the surface of the liquid in a tank by producing a sufficient underpressure in a gas-filled space above the surface of the liquid in the tank by means of a vacuum pump.

A leak preventing device is previously known from WO 87/02650 A1. This previously known device has the form of a leak sealing pad which is to be attached to an outer wall of a tank so as to cover a leak opening in the tank wall and thereby prevent gas or liquid from flowing out of the tank through the leak opening. The pad is pressed against the tank wall under the effect of an underpressure generated in a vacuum chamber of the pad by means of a vacuum pump. However, this leak preventing device is only suitable for use when it comes to an easily accessible leak concentrated to a limited area.

OBJECT OF THE INVENTION

The object of the present invention is to provide a new and favourable leak preventing device for preventing liquid from leaking out of a damaged tank.

SUMMARY OF THE INVENTION

According to the present invention, the above-mentioned object is achieved by a leak preventing device having the features defined in claim 1.

The leak preventing device of the present invention comprises:

• • a floating body with a buoyancy which makes it capable of floating at the surface of the liquid in the tank with at least an upper part of the floating body located above the surface of the liquid in the tank; and
  • a flexible hose with a first end and an opposite second end, the first end of the hose being fixed to the floating body and the hose being fixed to a wall of the tank at a point of attachment at a distance from said first end, wherein the hose extends freely inside the tank between the floating body and said point of attachment and wherein the second end of the hose is connected or connectable to a suction side of a vacuum pump so as to allow gas to be drawn off via the hose from a gas-filled space in the tank above the surface of the liquid in the tank in order to produce an underpressure in said space.

With the leak preventing device of the present invention, a leak-preventing underpressure may be achieved inside a tank in a simple manner. When liquid leaks out of the tank through a leak below the surface of the liquid in the tank, for instance when the tank has been damaged due to an accident, a vacuum pump is to be connected to the flexible hose inside the tank and the vacuum pump is to be operated in order to draw off gas from the gas-filled space in the tank above the surface of the liquid in the tank via the flexible hose and thereby produce an underpressure in said space sufficient for preventing liquid from continuing to leak out of the tank through said leak. The floating body will always float at the surface of the liquid in the tank irrespective of the prevailing inclination of the tank, and the floating body may thereby ensure that the flexible hose always is maintained in fluid communication with the gas-filled space in the tank above the surface of the liquid in the tank. Furthermore, the leak preventing device of the present invention may be used even if the leak opening is inaccessible.

According to an embodiment of the invention, said first end of the hose is fixed to the floating body in such a manner that the hose projects from the underside of the floating body at the centre thereof. Hereby, the weight of the hose will contribute in keeping the floating body floating in a correct position with its underside facing vertically downwards.

According to another embodiment of the invention, said second end of the hose is connected to a shut-off valve, which is fixed to the tank and accessible from the outside of the tank. The shut-off valve makes it easy to put the flexible hose inside the tank in communication with a vacuum pump when so needed and to otherwise keep the flexible hose disconnected from the ambient air.

According to another embodiment of the invention, said shut-off valve is connected to a coupling member, which is configured for releasable engagement with a corresponding coupling member arranged at an end of a suction hose from a vacuum pump. Hereby, a vacuum pump may easily and rapidly be connected to the flexible hose inside the tank when so needed.

According to another embodiment of the invention, the flexible hose is connected to one or more further shut-off valves, which are fixed to the tank at a distance from each other and accessible from the outside of the tank, wherein each such further shut-off valve is connected to a coupling member which is configured for releasable engagement with a corresponding coupling member arranged at an end of a suction hose from a vacuum pump. Each shut-off valve with its associated coupling member constitutes an access point through which a vacuum pump may be connected to the flexible hose inside the tank. By providing several such access points, the risk that the tank, in connection with an accident, would end up in a position in which no access to the flexible hose inside the tank is possible is reduced.

Further advantageous features of the leak preventing device of the present invention will appear from the following description and the dependent claims.

The invention also relates to a tank for transporting liquid having the features defined in claim 11.

Further advantageous features of the tank of the present invention will appear from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the appended drawings, a specific description of embodiments of the invention cited as examples follows below. In the drawings:

FIG. 1 is a schematic longitudinal section through a tank provided with a leak preventing device according to an embodiment of the present invention,

FIG. 2 is a schematic longitudinal section through the tank of FIG. 1, as seen with a vacuum pump connected to the flexible hose inside the tank,

FIG. 3 is a detail enlargement of the encircled area III in FIG. 1

FIG. 4 is a detail enlargement of the encircled area IV in FIG. 2,

FIG. 5 is a schematic perspective view from below of a floating body included in the leak preventing device of FIG. 1,

FIG. 6 is a schematic perspective view from above of the floating body of FIG. 5,

FIG. 7 is a schematic vertical section through the floating body of FIGS. 5 and 6,

FIG. 8 is a schematic planar view from above of the floating body of FIGS. 5 and 6, and

FIG. 9 is a schematic vertical section through a floating body according to an alternative variant.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

A leak preventing device 1 according to an embodiment of the present invention is schematically illustrated in FIGS. 1-4. The leak preventing device 1 is to be used with a tank 2 for transporting and/or storing liquid in order to prevent liquid from leaking out of the tank through a hole or crack in a wall of the tank below the surface 3 of the liquid in the tank if the tank is damaged due to an accident or wear. Thus, the leak preventing device 1 is to be pre-mounted to the tank 2 so as to be ready for use in a possible situation when the tank is damaged and liquid starts to leak out of the tank.

The leak preventing device 1 comprises a floating body 4 which is configured to have such a buoyancy that it is capable of floating at the surface 3 of the liquid in the tank 2 with at least an upper part of the floating body 4 located above the surface 3 of the liquid in the tank. The leak preventing device 1 also comprises a flexible hose 5 with a first end 6a and an opposite second end 6b. The first end 6a of the hose is fixed to the floating body 4 and the hose 5 is fixed to a wall 7 of the tank 2 at a point of attachment 8 at a distance from said first end 6a, wherein the hose 5 extends freely inside the tank 2 between the floating body 4 and said point of attachment 8. The second end 6b of the hose is connected or connectable to a suction side of a vacuum pump 9 (see FIG. 2) so as to allow the vacuum pump to draw off gas via the hose 5 from a gas-filled space 10 in the tank 2 above the floating body 4 and above the surface 3 of the liquid in the tank in order to reduce the pressure in said space 10 to such a low value that leakage of liquid from the tank 2 through a possible leak below the surface 3 of the liquid is prevented.

In the illustrated embodiment, the second end 6b of the hose is connected to a shut-off valve 11, which is fixed to the tank 2 and accessible from the outside of the tank. The shut-off valve 11 is connected to a coupling member 13 which is configured for releasable engagement with a corresponding coupling member 14 (see FIG. 4) arranged at an end of a suction hose 15 from a vacuum pump 9.

The flexible hose 5 is with advantage connected to two or more shut-off valves 11 which are fixed to the tank 2 at a distance from each other and accessible from the outside of the tank 2, as illustrated in FIGS. 1-4, wherein each shut-off valve 11 is connected to a coupling member 13 configured for releasable engagement with a corresponding coupling member 14 arranged at an end of a suction hose 15 from a vacuum pump 9. In the illustrated example, the leak preventing device 1 comprises three shut-off valves 11 with associated coupling members 13. The shut-off valves 11 are connected to each other by means of connecting pipes 16 which are mounted to the tank 2 on the outside thereof. The connecting pipes 16 may as an alternative be mounted inside the tank 2.

Each shut-off valve 11 comprises a valve member (not shown) which is moveable by means of a maneuvering member 12 between a closed position and an open position. The maneuvering member 12 may for instance have the form of a lever or knob.

In the illustrated embodiment, the suction hose 15 of the vacuum pump 9 is to be connected to one of the shut-off valves 11 when need arises. However, the leak preventing device of the present invention may as an alternative comprise a vacuum pump which is permanently connected to the flexible hose 5 inside the tank 2 via a shut-off valve 11.

The first end 6a of the flexible hose 5 is with advantage fixed to the floating body 4 in such a manner that the hose 5 projects from the underside 17a of the floating body at the centre thereof, as illustrated in FIGS. 5 and 7. In the embodiments illustrated in FIGS. 5-9, the floating body 4 is provided with a suction channel 18, wherein the first end 6a of the flexible hose 5 is connected to a lower end 19a of the suction channel 18 and an inlet opening 20 is arranged at an upper end 19b of the suction channel 18. The inlet opening 20 is provided in a part of the floating body 4 which is configured to be located above the surface 3 of the liquid in the tank 4 when the floating body 4 is floating at the surface 3 of the liquid in the tank. In the illustrated examples, the suction channel 18 extends across the floating body 4 from the underside 17a of the floating body to the upper side 17b thereof along the centre axis of the floating body 4.

In the embodiment illustrated in FIGS. 5-8, the inlet opening 20 of the suction channel 18 is arranged at the upper end of a pipe 21 which projects from the upper side 17b of the floating body 4, wherein the upper end of the pipe 21 is received in a cover 22 which is configured to prevent liquid from splashing into the suction channel 18 through the inlet opening 20. The cover 22 is fixed to the pipe 21 by means of a supporting member 23 in the form of a plate or the similar, wherein gas is allowed to flow into the cover 22 towards the inlet opening 20 of the suction channel 18 through gaps 24 between the supporting member 23 and an inner wall of the cover 22, as illustrated in FIGS. 7 and 8, or through gaps in the supporting member 23.

In the embodiment illustrated in FIG. 9, a check valve 25 is arranged at the inlet opening 20 of the suction channel 18 in order to keep the inlet opening closed when no gas to is drawn off via the flexible hose 5 from the gas-filled space 10 above the surface 3 of the liquid in the tank 2. The check valve 25 comprises a valve member 26, for instance in the form of a disc, which is moveably mounted to the float 4 at the upper end 19b of the suction channel 18. Under the effect of a suction effect in the suction channel 18 produced by a vacuum pump 9, the valve member 26 is moveable from a closed position, in which the valve member 26 covers the inlet opening 20 of the suction channel 18 and thereby prevents liquid from splashing into the suction channel 18 through the inlet opening 20, to an open position, in which the valve member 26 is swung away from the inlet opening 20. A stop member 27 is with advantage arranged at the inlet opening 20 of the suction channel 18 in order to define the closed position of the valve member 26, wherein the valve member 26 is configured to abut against this stop member 27 in its closed position. The valve member 26 is preferably spring-loaded so as to assume its closed position under the effect of the spring force from a spring member (not shown) acting on the valve member 26.

The invention is of course not in any way restricted to the embodiments described above. On the contrary, many possibilities to modifications thereof will be apparent to a person with ordinary skill in the art without departing from the basic idea of the invention such as defined in the appended claims.

Claims

1. A leak preventing device for preventing liquid from leaking out of a damaged tank (2), wherein the leak preventing device (1) comprises:

a floating body (4) with a buoyancy which makes it capable of floating at the surface (3) of the liquid in the tank (2) with at least an upper part of the floating body (4) located above the surface (3) of the liquid in the tank (2); and

a flexible hose (5) with a first end (6a) and an opposite second end (6b), the first end (6a) of the hose being fixed to the floating body (4) and the hose (5) being fixed to a wall (7) of the tank (2) at a point of attachment (8) at a distance from said first end (6a), wherein

the hose (5) extends freely inside the tank (2) between the floating body (4) and said point of attachment (8) and

the second end (6b) of the hose is connected or connectable to a suction side of a vacuum pump (9) to allow gas to be drawn off via the hose (5) from a gas-filled space (10) in the tank (2) above the surface (3) of the liquid in the tank (2) to produce an underpressure in said space (10).

2. A leak preventing device according to claim 1, wherein said first end (6a) of the hose is fixed to the floating body (4) in such a manner that the hose (5) projects from the underside (17a) of the floating body at the centre thereof.

3. A leak preventing device according to claim 1, wherein

a suction channel (18) is arranged in the floating body (4);

the suction channel (18) has an inlet opening (20) at its upper end, this inlet opening (20) is arranged in a part of the floating body (4) which is configured to be located above the surface (3) of the liquid in the tank (2) when the floating body (4) is floating at the surface (3) of the liquid in the tank (2); and

the first end (6a) of the hose is connected to a lower end (19a) of the suction channel (18).

4. A leak preventing device according to claim 3, wherein a check valve (25) is arranged at the inlet opening (20) of the suction channel (18) to keep the inlet opening closed when no gas to is drawn off via the hose (5) from said gas-filled space (10) in the tank (2).

5. A leak preventing device according to claim 3, wherein

the inlet opening (20) of the suction channel (18) is provided at an upper end of a pipe (21) which projects from the upper side (17b) of the floating body (4); and

the upper end of said pipe (21) is received in a cover (22), which is configured to prevent liquid from splashing into the suction channel (18) through the inlet opening (20).

6. A leak preventing device according to claim 3, wherein the suction channel (18) extends across the floating body (4) from the underside (17a) of the floating body to the upper side (17b) thereof.

7. A leak preventing device according to claim 1, wherein said second end (6b) of the hose is connected to a shut-off valve (11), which is fixed to the tank (2) and accessible from the outside of the tank (2).

8. A leak preventing device according to claim 7, wherein said shut-off valve (11) is connected to a coupling member (13), which is configured for releasable engagement with a corresponding coupling member (14) arranged at an end of a suction hose (15) from a vacuum pump (9).

9. A leak preventing device according to claim 7, wherein

the flexible hose (5) is connected to one or more further shut-off valves (11), which are fixed to the tank (2) at a distance from each other and accessible from the outside of the tank (2); and

each such further shut-off valve (11) is connected to a coupling member (13), which is configured for releasable engagement with a corresponding coupling member (14) arranged at an end of a suction hose (15) from a vacuum pump (9).

10. A leak preventing device according to claim 9, wherein the shut-off valves (11) are connected to each other by connecting pipes (16) mounted to the tank (2) on the outside or on the inside thereof.

11. A tank for transporting liquid, wherein the tank (2) is provided with a leak preventing device (1) according to claim 1.

12. A leak preventing device according to claim 2, wherein

a suction channel (18) is arranged in the floating body (4);

the suction channel (18) has an inlet opening (20) at its upper end;

this inlet opening (20) is arranged in a part of the floating body (4) which is configured to be located above the surface (3) of the liquid in the tank (2) when the floating body (4) is floating at the surface (3) of the liquid in the tank (2); and

the first end (6a) of the hose is connected to a lower end (19a) of the suction channel (18).

13. A leak preventing device according to claim 12, wherein a check valve (25) is arranged at the inlet opening (20) of the suction channel (18) to keep the inlet opening closed when no gas to is drawn off via the hose (5) from said gas-filled space (10) in the tank (2).

14. A leak preventing device according to claim 12, wherein

the inlet opening (20) of the suction channel (18) is provided at an upper end of a pipe (21) which projects from the upper side (17b) of the floating body (4); and

the upper end of said pipe (21) is received in a cover (22), which is configured to prevent liquid from splashing into the suction channel (18) through the inlet opening (20).

15. A leak preventing device according to claim 14, wherein the suction channel (18) extends across the floating body (4) from the underside (17a) of the floating body to the upper side (17b) thereof.

16. A leak preventing device according to claim 13, wherein the suction channel (18) extends across the floating body (4) from the underside (17a) of the floating body to the upper side (17b) thereof.

17. A leak preventing device according to claim 12, wherein the suction channel (18) extends across the floating body (4) from the underside (17a) of the floating body to the upper side (17b) thereof.

18. A leak preventing device according to claim 5, wherein the suction channel (18) extends across the floating body (4) from the underside (17a) of the floating body to the upper side (17b) thereof.

19. A leak preventing device according to claim 4, wherein the suction channel (18) extends across the floating body (4) from the underside (17a) of the floating body to the upper side (17b) thereof.

20. A leak preventing device according to claim 15, wherein said second end (6b) of the hose is connected to a shut-off valve (11), which is fixed to the tank (2) and accessible from the outside of the tank (2).