GB2261597A - A tank washing device - Google Patents

Abstract

A tank washing device comprising a washing head (17) adapted to be mounted above the base of a circular tank (10), having a washing liquid supply pipe (21) and a series of nozzles (24) to direct jets of washing liquid across the tank base and/or walls to clean same. The washing head (17) is rotated about a vertical support column (16), and the nozzles (14) are mounted on horizontal pipes (20) forming part of the washing head (17) and themselves rotatable about their own horizontal axes thus to enable the nozzles (14) to sweep the entire interior surface of the tank by controlled rotation of the washing head (17) and the nozzle pipes (20). <IMAGE>

Description

A TANK WASHING DEVICE THIS INVENTION concerns a device for washing the bottom and/or walls of a tank such as a sedimentation tank to ensure that all of the settled solids are directed into a drain enclosure, usually in the centre of the tank. Also, the device is designed particularly though not exclusively for washing circular tanks and mounted over a generally central region thereof.

According to the present invention a tank washing device comprises a washing head, means for mounting same above the base of a tank, means to supply a washing liquid to the washing head, one or more nozzles mounted on the washing head to direct a jet or jets of washing liquid towards the tank base and/or walls, the washing head being movable over the interior of the tank such that the liquid jet or jets may be played across the tank base and/or walls to clean same, and drive means for moving the washing head.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view taken from above a tank washing device made in accordance with the invention; and Fig. 2 is a vertical sectional view thereof.

In the embodiment illustrated the device is adapted to wash the vertical wall and inwardly sloping base of a circular tank 10. As will be seen from Fig. 2, the vertical wall 11 of the tank contains an outlet weir 12 from which effluent flows out of the tank to a drain facility (not shown), whilst sludge settling in the tank is deposited in a drain enclosure 13 in the centre of the base 14.

Mounted centrally over the drain enclosure 13 is a tripod 15 supporting a column 16 on which is mounted a washing head generally indicated at 17 which can rotate through 360" about a vertical axis over the column 16.

Fig. 1 shows the washing head 17 to consist of a central pipe 18 extending radially outwards in two opposed horizontal directions from the column 16, a pair of feed pipes 19 communicating with and extending from the respective ends of the pipe 18 transversely thereto, and a pair of nozzle pipes 20 extending respectively between and communicating with the ends of pipes 19.

A fixed radially disposed supply pipe 21 delivers washing liquid via central rotary union 22 to the interior of a ported member 23 which is in communication with pipe 18. Alternatively, the supply may be directed upwardly from beneath the device, via column 16.

Located at spaced positions along each pipe 20 is a series of three nozzles 24 which are directed at different angles from pipe 20 thus to produce three separate "footprints" 25 of washing liquid onto the bottom of the tank 10.

A first electric motor 26 is mounted on supply pipe 21 and, via a drive belt or chain 27 or a direct geared drive, is adapted to rotate the washing head 17 about the vertical axis of column 16 as indicated by arrow 28.

Pipes 20 are rotatably mounted with respect to pipes 19 whereby the nozzles may be swung through an arc about the horizontal axes of their respective pipes 20 to move the three footprints 25 inwardly and outwardly with respect to the centre of the tank. Rotation of the pipes 20, preferably in opposite directions, is provided by a second electric motor 29, a belt drive 30 and meshing pinions 31.

It can be seen therefore that as the washing head 17 is rotated about its vertical axis and pipes 20 are rotated about their horizontal axes, by appropriate control of such movements, the entire surface of the wall and bottom of the tank 10 may be washed causing accumulated sludge to be directed towards the central drain enclosure 13.

By providing nozzles directing jets of washing liquid in two diametrically opposed directions, the entire tank may be cleaned during one half of a revolution of the washing head 17 and the back pressure of the liquid jets is balanced across the head 17. If required, the tank may be washed several times by one or more complete cycles.

Whilst in Fig. 2 to illustrate the arc through which the nozzles may be swung, the respective pipes 20 are shown in two different rotational attitudes, it is preferable to ensure that the two sets of nozzles are pointing at the same inclination instantaneously thus to ensure adequate balance of the system.

It is not intended to limit the invention to the above example only. For example, instead of providing two sets each of three nozzles, each pipe 20 may carry a single central nozzle in some cases, but this would probably necessitate several cycles of the washing head before the entire tank is cleaned.

Ideally, a washing sequence proceeds by initially directing the nozzles 24 at the upper region of the tank wall as illustrated at the left-hand side of Fig. 2, and thereafter gradually swinging the nozzles downwardly as the washing head 17 is rotated around its vertical axis.

In a further alternative arrangement, the pipes 20 may be fixed with respect to pipes 19 and may carry sufficient fixed nozzles to provide a full "sweep" of the wall 11 and base 14 of the tank merely by rotation of the entire washing head 17. The nozzles can be actuated simultaneously, or each nozzle, whether on a fixed or a rotatable pipe 20, may be actuated individually by a separate flow control valve. In this way, particularly if the pipes 20 are fixed, a washing cycle may commence on the wall 11 and progressively sweep downwards towards the control outlet 13 by a sequenced actuation of the nozzle valves either individually or in pairs or groups.

In another embodiment, one or more washing heads may be adapted to travel bodily over the tank bottom in a circular or straight path.

In a still further embodiment, two or more such washing devices with movable washing heads, may be provided in an elongate rectangular tank provided adequate coverage can be ensured by the available liquid jets.

Claims (12)

1. A tank washing device comprising a washing head, means for mounting same above the base of a tank, means to supply a washing liquid to the washing head, one or more nozzles mounted on the washing head to direct a jet or jets of washing liquid towards the tank base and/or walls, the washing head being movable over the interior of the tank such that the liquid jet or jets may be played across the tank base and/or walls to clean same, and drive means for moving the washing head.

2. A tank washing device according to Claim 1, wherein the washing head is adapted to be mounted above a central region of a circular tank, and is rotatable about an upright axis such that said one or more nozzles may direct a jet or jets of washing liquid in a sweeping action around the tank bottom and/or walls as the washing head rotates.

3. A tank washing device according to Claim 1 or Claim 2, wherein each said nozzle is further movable with respect to the washing head such that the or each liquid jet may be moved inwardly or outwardly with respect to the centre of the tank.

4. A tank washing device according to any preceding claim, including a plurality of nozzles mounted on the washing head and adapted simultaneously to direct several jets of washing liquid towards different parts of the tank wall and/or base.

5. A tank washing device according to any one of Claims 1 to 3, wherein the or each nozzle is provided with an individually operable valve to control the associated jet of washing liquid.

6. A tank washing device according to Claim 1, wherein said washing head is rotatably mounted on a supporting column to stand above the centre of the base of the tank and consists of a central pipe extending radially outwards from the supporting column, at least one feed pipe communicating with and extending from at least one end of the central pipe transversely thereto, and at lest one nozzle pipe communicating with the feed pipe or pipes.

7. A tank washing device according to Claim 6, wherein the or each nozzle pipe is rotatable about its axis whereby the or each nozzle may be swung through an arc about the axis of the respective nozzle pipe.

8. A tank washing device according to Claim 6, wherein the washing liquid supply means comprises a fixed pipe extending over the tank and connected to the washing head so as to permit rotation of the latter about a vertical axis relative to the supply pipe.

9. A tank washing device according to Claim 8, including a pair of drive motors, one mounted on said fixed supply pipe and having a drive connection to the washing head, and the other being mounted on the rotatable washing head and having a drive connection to the or each nozzle pipe.

10. A tank washing device according to Claim 1 or Claim 2, wherein the or each nozzle pipe is non-rotatably fixed to the washing head and carries, at different angles of inclination a plurality of fixed nozzles adapted collectively to direct several jets of washing liquid simultaneously towards said tank wall and/or base.

11. A tank washing device according to Claim 1, which is adapted to travel bodily over the tank bottom in a curved or straight path, the bodily travel thereof serving to wash the tank base and/or walls progressively.

12. A tank washing device, substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings.