The present invention is related to a cleaning device, especially for cleaning the interior surfaces of tanks.

Presently there exists a demand for reliable and accurate cleaning systems for tanks, such as for cleaning tanks in ships as well as land based tanks, stationary as are found in factories etc, as well as mobile such as transportation tank units for roads and rails.

A number of different types of cleaning devices for such tanks are available on the market, some of which being adapted for permanent installation, others for installation and removement after use.

Furthermore cleaning devices are available to be hoisted down into the tank, rotated and moved around in the tank by the pressure from the cleaning fluid. Such a solution may lead to damage on the interior of the tank, such as bulk heads, as well as on the jet nozzles and generally the cleaning equipment. Using the pressure of the cleaning fluid to operate the cleaning devise as is usual, means that a substantial part of the pressure cannot be utilized for the cleaning process, thereby decreasing the effect of the cleaning fluid jets substantially.

With the ^" cleaning device according to the present invention, a stationary, reliable and cleaning device is provided which is controlled from a central command station, preferably computerized to adapt the cleaning sequenze to the interior shape for the tank or tanks in question. The cleaning operation may be set into operation from a navigating bridge on board a ship or a central operation station in a factory. The cleaning work normally has to be performed very quickly to clear the tank for utilazation and with a large degree of accuracy in all parts of the tank. A continous control of all parameters in the cleaning process is ensured by use of a normally already existing computer syste .

The above mentioned advantages are acheived with the cleaning device according to the present invention sa defined

with the features stated in the claims.

In the drawing Fig. 1 discloses schematically an example of using the present invention in a tank on board a ship, comprising three cleaning balls connected to a drive means on top of the upper deck, Fig. 2 discloses an axial section through a cleaning ball and Fig. 3 discloses a side view of a nozzle segment.

Fig. 1 discloses schematically the cleaning device according to the present invention, suspended from a deck or tank top 12 on which a drive means 2 is arranged, comprising the drive for the drive shaft of the cleaning device and for pumps etc. for the cleaning fluid. From the tank top a pipe 3 is extending downwards to a cleaning ball 1. Depending of the height of the tank further units comprising pipe 3 and cleaning ball 1 may be connected to the lower ball of the cleaning device such that the cleaning device may comprise three cleaning balls 1 arranged above each other within the height of the tank.

In the interior of.the pipe 3 extends a shaft 4 through the tank top 12, being preferably driven by an electric or hydraulic motor in the drive means 2. The shaft 4 is extending through the cleaning ball 1, driving a gear 4 meshing with the gear 6 connected with an horizontal shaft 7. The horizontal shaft is extending through an aperture in the axis 4 to the other half of the cleaning ball, a nozzle segment 9 being connected with both ends of the horizontal shaft 7. Each nozzle segment 9 is comprising two nozzles 8 being arranged diametrically opposed to each other.

When rotating the vertical shaft 4, the gear 5 will drive also the horizontal shaft 7 in such a way that the ball will have the same number of revolutions as the shaft 4. Preferably the gear system will have an exchange between the gears 5 and 6, such that the nozzle segments 9 on both sides of the ball rotate with another number of revolutions, whereby the four nozzles 4 on the two nozzle segments 9 very e ficiently will be directed to all surfaces of the tank. This as well as other parameters being adjusted to the interior tank shape in question.

The pressurized cleaning fluid is guided from the drive unit 2 through the interior 13 of the pipe 3, into the, or each ball 1 and further to the interior of the nozzle segment and the

nozzle aperture. From hear the cleaning fluid is driven without substantial decrease of the pressure out of the nozzles 8. In each of the nozzle segments are arranged diametrically opposed directed, nozzles 8. Furthermore the nozzles 8 in each nozzle 5 segment of each ball are arranged preferably parallel in such a way that reaction forces from the four nozzles substantially neutralize each other without effecting the balls.

As disclosed in Fig. 1 the lowermost cleaning ball comprises a cover 10 closing the ball and thereby also the o interior 13 of the pipe, thereby closing the fluid flow at the lowermost ball.

The cleaning ball principally comprises a middle unit in form of a ball disc having a flat bottom and top, the pipe being connected to the top by means of a cover 11 and the bottom s as well being flat, whereby a further pipe 3 by means of a cover 11 can be connected to the underside of the ball disc, or terminated as described above, by means of a cover 10. The nozzle segments 9 and the covers 10 and 11 are tightly connected in such a way that fluids from the interior of the tank cannot protude o into the different parts of the cleaning ball, such as gears in the interior of the balls.

The driving device comprises all components necessary to drive the cleaning system itself, including electrical motors, pumps and necessary electronics. Likewise a safety valve is 5 provided to ensure supply of air, thereby avoiding underpressure in the piping system. Furthermore the driving device 2 preferably comprises pipe connections to the valve for selectively supply of chemical cleaning fluid and clean water, whereby these units of security reasons are shielded against other parts of the 0 driving device. In operation the shaft 4 is driven by the electric motor in the driving device 2. The electric motor may be replaced by a hydraulic drive system.

The pipe 3 may be provided by braces 14, especially by arrangement of several balls above each other. When the shaft 4 5 is rotated, the gear 5 drives the gear 6 on the horizontal shaft 7, thereby rotating the nozzle segment 9. The shaft 7 is extending through the ball and connecting the two nozzle segments 9 with each other in such a way that they are rotating synchron¬ ous. The transversal shaft 7 rotates the shaft 4 in such a way

that the ball is rotated around its own axis. The pressure from the cleaning fluid in the interior 13 of the pipe 3 is transmit¬ ted without substantial pressure fall to the to nozzles 8 in each nozzle segment 9. Choice of . fluid in the cleaning system, the chemical cleaning system and possibly clean water as well as the rotation of the shaft 4 is controlled by a board computer considering thereby the size and shape of the tank as well as the last cargo contained in the tank.

With the cleaning device according to the present invention a cleaning of the tank with high accuracy may be performed, thereby considering the last cargo contained in the tank. The cleaning furthermore is performed successively on the interior inner surface of the tank using a cleaning pressure which ensures correct cleaning in the interior tank. If in certain cases an increased cleaning pressure should be needed, a certain number of the nozzles may be blocked.