Background of the invention

The invention relates to apparatus for the cleaning of closed compartments by means of sprayed-out liquid, and comprising a housing with a stationary part to which the liquid is supplied, and on which there is mounted a rotatable part having a hub with spray nozzles suspended in bearings herein, and with a turbine driven by the liquid and having a planet gear mounted in the stationary part for the turning of the rotatable part and the nozzles in such a manner that the liquid sprayed out through the nozzles during the rotation can sweep the whole of the interior of the compartment.

Apparatus of this kind is used especially for the internal cleaning of tanks within the foodstuffs industry, the che¬ mical and pharmaceutical industries and similar industries where tanks must be held clean.

The cleaning is effected by means of liquid which under pressure is supplied to the apparatus through a pipe, after which it is sprayed out through nozzles which rotate around a horizontal axis as well as around a vertical axis, so that after a certain number of revolutions the apparatus will have cleaned the whole of the inside of the tank.

Hitherto-known apparatus for this purpose comprises a housing in which there is mounted a turbine in the liquid flow, so that a gear can be coupled to and in extension of the turbine axle. The gear can turn a part of the housing around a vertical axis in relation to the remaining fixed part of the housing, to which is fastened a supply pipe for the liquid.

Mounted radially on the rotatable part of the housing there is a hub on which the nozzles are mounted, in that said nozzles rotate around their horizontal axes by means of a gear exchange. This apparatus is thus driven by the clean¬ ing liquid, in that pressure from the main flow drives the turbine, after which the liquid is led out through an opening in the bottom of the housing. The main flow is de¬ flected in the housing at right-angles and is fed through the hub and out through the nozzles.

However, this construction is encumbered with drawbacks and disadvantages.

First and foremost, there is a considerable loss of energy in the flow of liquid through the apparatus, due particularly to the sharp deflection of the liquid flow.

To this must be added that the apparatus is developed to work only in the vertical position. This limits the use of the apparatus to tanks, where there is access from the top. Finally, there is a risk that the housing gets sullied both internally and externally by the contents of the tank, and herewith possibly be unable to function because of the inability to rotate. Similarly, there can be a risk of pollution of the contents of the tank.

In order to overcome these drawbacks, it is known from EP publication no. 0,004,954 to build a turbine into the actual main flow in the apparatus, said turbine being used via a planetary gear to turn both a rotatable part of the housing and a hub with the nozzles, while at the same time the liquid is sprayed out to soften and clean the inside of the tank.

The drive for the turning of the hub is configured as a conical gear which extends externally on the housing and

which is therefore free-lying in the tank. Moreover, the parts are suspended in ball bearings, all of which are built into totally or partially closed bearing housings.

The result of this construction is that the apparatus has a relatively poor efficiency, especially in strongly polluted environments where the gears easily get sullied, whereby their friction becomes great. In worst cases this can be so high that rotation ceases completely for reasons of blockage. Furthermore, the mounting of the bearings can give rise to operational problems, in that they are difficult to lubricate and keep clean because of the totally or partially closed mounting. This results in poor lubrication and herewith high friction and short lifetime for the bearings.

In addition, the outside of the housing easily gets dirty, in that the housing cannot avoid being sullied with the tank contents, with the risk that these infiltrate into the housing through drain holes and nozzles. This gives rise to a considerable risk of pollution of the tank contents, and demands a subsequent cleaning both internally as well as externally. Consequently, this means that the apparatus juust be cleaned, which is both troublesome and time- consuming.

Advantages of the invention

By configuring the apparatus according to the invention in such a manner that the gear's planet wheel is externally in engagement with a toothed rim mounted on the stationary part of the housing, said toothed rim being in engagement with a toothed rim on the hub, both toothed rims being surrounded by the housing, the advantage achieved first and foremost is that the apparatus can be of a very compact construction.

This is due to the internal positioning of the toothed rims, which allows the planetary gear to extend into the toothed rim on the stationary part. Moreover, this compact construction offers the further advantage that the apparatus becomes more stable, and the possibility is pro¬ vided of suspending the turbine axle in a lower bearing.

To this is added that the teeth can be rinsed through by the liquid, and hereby keep them lubricated and clean. The friction is hereby considerably reduced, which not only ensures smooth operation and herewith a long lifetime for the apparatus, but also a high degree of hygiene since the apparatus is held clean internally by the liquid. This is achieved without exposing the pressure liquid to any loss of pressure through the apparatus.

As disclosed in claim 2, by leading the liquid flow through the gear, the toothed rims and the bearings, and by dis¬ charging this liquid through outlet slots along adjacent end surfaces at the rotatable parts, an effective cooling, lubrication and cleaning of these parts is ensured, and herewith also security for a high degree of hygiene and long lifetime.

As disclosed in claim 3, by further configuring a number of outlet openings in the bottom of external recesses in the housing, it will not be possible for polluted parts to be deposited in these recesses.

As disclosed in claim 4, by configuring slots and openings in such a manner that the liquid flowing out will sweep the outside of the housing, the surface will automatically be cleaned during operation of the apparatus.

Finally, as disclosed in claim 5, it will be expedient to provide the hub with a shield which partly covers the out-

let slot, in that this will result in a strong stream of liquid being thrown back over the rotatable part, which is hereby held effectively clean.

The drawing

In the following, an example embodiment of the invention will be described in more detail with reference to the drawing, where

Fig. 1 shows an apparatus during operation seen from the outside with indications of the outflowing liquid streams,

fig. 2 shows a section through the apparatus, and

fig. 3 shows the course of the flow through the apparatus seen in section.

Description of the example embodiment

In the drawing is shown an example of a preferred embodi¬ ment of the invention.

The apparatus is built into a housing which comprises a stationary part 1 and a rotatable part 16 in the form of a pipe bend, and a hub 11 on which the nozzles 12 are mounted.

The stationary part 1 of the housing is configured as a truncated cone with a mounting stub 41 at the narrow end at the top.

The stub 41 has a thread in which a not-shown supply pipe for the inlet liquid 39 to the apparatus can be mounted. In addition to its function as supply pipe, the supply pipe

also serves to support the apparatus. It can be either a rigid pipe or a flexible hose.

Externally, the housing 1 has a number of recesses for assembly bolts 2, which are screwed into a ring 4 with a support piece 5 for a bearing ring 29 and a toothed rim 8, see especially fig. 2. The pipe bend 16 can hereby be suspended on the stationary part 1, in that the second bearing ring 31 is secured to the rotatable part 16.

Inside the housing 1 and along its centreline an axle 24 is mounted in a bearing bush 18 at the top, said bearing bush 18 being supported by a cone 25 having guide blades 33 along the edge, which are secured to the housing 1.

The axle 24 under the cone 25 is provided with a locking ring 28 for securing a rotor 23. Along the edge of the rotor 23 there are provided a number of rotor vanes 34, so that via the guide blades 33 the liquid 39 can make the rotor 23 rotate, and thus constitute the turbine which imparts movement to the moving parts of the apparatus, whereby the apparatus is driven by the medium.

These parts comprise an extension of the axle, which at the bottom is housed in a bush 18 resting against a bearing disk 19 in a bearing foot 20, which extends up from this part of the housing 16 which is formed as a 90° pipe bend.

It will be seen clearly in the drawing that the axle 24 extends along the centreline of the housing 1 and along the centreline of the inlet part's pipe bend 16.

On the lower section of the axle there is secured a pinion

27 which is in engagement with a pair of planet gears 15 which are mounted on axles 17 secured in a holder 21. The planet gears 15 are in engagement externally with an

internal tooth gearing in the toothed rim 8, which is secured to the housing's stationary part 1 as earlier described.

On the lower part of the planet gears 15 there are provided output gears 26 which are in external engagement with an internal toothed rim 14 secured to this part of the housing 16.

The exchange ratio between the planet gears 15, 26 and the toothed rims 8, 14 is different, so that when the turbine is turned via the planet gear, there will arise a turning movement of the housing 16 in relation to the stationary part 1.

In the opposite end of the pipe bend 16 there is suspended a hub 11 in a bearing 29, 31, the one bearing ring 31 of which is secured in the housing 16, while the other bearing ring 29 is secured to the hub 11 via an internal ring 6 with a hub which is bolted to the hub 11 on which the nozzles 12 are mounted. The ring is provided externally with a conical gear 13, this being in engagement with the external conical teeth on the toothed rim 8 which is secured to the stationary part of the housing 1. When the pipe bend 16 is turned, the hub 11 with the nozzles 12 will thus be rotated around the centreline at right-angles to the turbine's centreline for the outlet part of the pipe bend 16.

Behind the heads of the bolts 2 in the stationary part 1 of the housing there are also configured some throughgoing holes 35, and outlet slots are configured between the moving parts of the apparatus, in that there is a slot 36 between the housing's stationary part 1 and the movable part 16, and a slot 37 between the movable part 16 and the hub 11.

Furthermore, there is a drain hole 38 in the bottom of the pipe bend 16 for the evacuation of liquid from the housing after the apparatus has been used.

The flow conditions in and around the apparatus will now be described, especially with reference to figs. 1 and 3.

The supply liquid 39, which is also the cleaning liquid, can be any suitable solution for the softening and cleaning of the tank compartment. As an example, the liquid can have a pressure of around 8 bar and a capacity of around 10

3 m /h. An adequately effective cleaning can hereby be carried out up to a diameter of around 6-8 m.

The liquid 39 is fed to the turbine's rotor 23 in the centre of the flow. A small amount of liquid is led out through the openings 35 in the bottom of the swages which are in this part of the housing. The space behind the bolt heads and the countersunk external housing surfaces are thus held clean, and the liquid will also hold the bolt heads clean externally.

The liquid continues from the rotor down through the pipe bend 16 through the planet gear and the drive, which are hereby lubricated and cleaned, in that a smaller part of the liquid runs through the two bearings 29, 31 and out through the horizontal slot 36 and the vertical slot 37 respectively, which are hereby lubricated and flushed clean.

The main flow continues in an even arc, see fig. 3, towards the nozzles 12 via liquid guides 32, see fig. 2, to the nozzles 12. In the example shown, four nozzles are mounted for the spraying-out of liquid 40, which constitutes the tank-cleaning part of the liquid flow. There can, however, be mounted a larger or a smaller number of nozzles depend-

ing on the desired cleaning program.

In order to utilize the liquid flowing out through the openings 35 and the slots 36 for an effective external cleaning of the apparatus and the supply pipe, the hub 11 is configured with a shield 30, see fig. 2, to which liquid is led, e.g. via a channel 3 in the hub 11, and by such an orientation of the slots that the liquid is emitted in a certain direction whereby it is able to sweep both the pipe bend 16 as well as the stationary part 1 and the supply pipe during operation, and the hub 11 can similarly be held clean.

The hub 11 will thus be cleaned by the flow of liquid which occurs via the slot 36, so that the apparatus as a whole is held clean even in strongly polluted environments.

This ensures that the apparatus can always function, since the moving parts are clean, and that the demands regarding hygiene are fulfilled, the reason being that the whole of the apparatus is clean both internally and externally.

The whole of the apparatus can be made of stainless steel and synthetic materials, whereby the apparatus will be able to fulfil the highest demands made on equipment for use in connection with foodstuffs and processes.

Moreover, the pressure loss through the apparatus is very small, the reason being that the main flow runs in an even and unbroken arc, while the two diverted cleaning flows are used for both external and internal cleaning.