The invention relates to a device for washing, flushing and drying objects, such as catering carts, for use on board aircraft, and comprising a housing to receive the objects which are secured by holding means which are pro¬ vided in the housing, said housing accommodating washing nozzles, flushing nozzles and means for centrifuging the objects during washing, flushing and drying.

In connection with the tremendous number of flights all over the world very huge amounts of meals are prepared which are consumed by the passengers on the individual flights. The transport of these meals is performed with so-called catering carts, also called trolleys, which are packed in a large-scale kitchen and are driven out to the aircraft, following which a meal is served to the passen- gers . Once the aircraft has landed, the catering carts are packed with the soiled service and are returned to another large-scale kitchen in another airport.

It is clear that the catering carts will inevitably be soiled to some extent when they return to the large-scale kitchen.

Therefore these catering carts need to be cleaned, and since a very large number of catering carts is in circu- lation, it is necessary that the cleaning of these is performed in an efficient and effective manner, i.e. that cleaning of the individual catering carts is performed at a great speed.

A machine for the cleaning of catering carts is known e.g. from the published Swedish patent application No. 91

12 20. This known machine consists of a housing which has a door through which the catering carts may be run into a compartment in the housing. The carts are secured by some gripping means, and, when placed in the housing, the carts are washed during centrifugation. After washing, the carts are dried, which also takes place by centrifu ^¬ gation, but at a somewhat greater speed. It is clear that the higher the speed of the centrifugation is, the faster the carts will be dried. According to this Swedish pub- lished patent application, this washer operates at cen¬ trifugation speeds in the range from 30 to 90 revolutions per minute.

The European published patent application No. 569 885 discloses a similar machine in which the centrifugation can take place according to different patterns of motion, such as oscillating or in step.

Although the above-mentioned known washers operate quite effectively and quickly, an increase in the centrifuga¬ tion speed will undoubtedly mean that the washing process time can be reduced. Doing so is not without problems, however, since an increase in the centrifugation speed will result in greater forces being applied to the carts. If, e.g., a plate has been left in the cart for some rea¬ son, it might be thrown out of the cart with a great force if the centrifugation speed is high.

Accordingly, the object of the invention is to provide a washer which allows the washing time to be reduced while maintaining sufficient safety conditions.

The object of the invention is achieved by a washer of the type mentioned in the opening paragraph, which is characterized in that the objects are confined in a cage during washing, flushing and drying.

It is ensured hereby that if some piece of tableware or a glass is left, such an object will be retained inside the cage even at a high centrifugation speed.

Expediently, the cage may be box-shaped, which is the most optimum in connection with catering carts which themselves are box-shaped.

When the cage is centrifuged together with the objects, it is ensured that if e.g. a plate or the like remains in a catering cart and is thrown out, it will hit the cage more "softly" than if it is thrown right out to the inner wall of the washer. The cage also protects the inner parts of the machine against damage caused by impacts, squeezing and wedging of loose parts coming from the washed objects.

As stated in claim 4, it is expedient that the cage is formed by a wire net which is arranged vertically slid- ably inside the housing, which is an advantage in terms of minimizing the weight of the cage.

When, as stated in claim 5, the holding means are formed by a rod which is fixed on each side of the cage, and the rod has slidable hooks which are adapted to engage an edge on the objects, a secure attachment of the catering carts is achieved during centrifugation, as the hooks have a good grip of an upper edge which is usually formed on the carts. The holding means additionally serve to en- sure that the doors on the carts can open during the process. If these are not attached, the carts will move to the inner side of the cage, and this will prevent the doors from opening. The slidable rod prevents overturning of a single cart when it stands by itself, and the ma- chine is subjected to the washing pressure.

In the event that a catering cart cannot be secured by the hooks, it is expedient, as mentioned in claim 6, if a spacer is provided on one or more of the inner sides of the cage, said spacer preventing the cart from leaning against the walls of the cage, which may cause the doors to be closed during washing.

In order to make the washing processes additionally ef¬ fective, it is advantageous that the housing has two ver- tically slidable doors, as stated in claim 7. This pro¬ vides the advantage that one door may serve as an inlet side for catering carts to be washed, while the other door may be used for removing cleaned doors.

For optimum utilization of the washing compartment itself in the machine, i.e. use of the machine in connection with small as well as ^' large carts, it is expedient, as stated in claim 8, that the rotation of the cage is pro¬ vided by means of a motor which transfers a rotary move- ment at the top of the housing, and that shafts transfer¬ ring the rotary movement to a rotatable floor are ar¬ ranged outside the cage. As a result, there will be no through shafts of any form centrally inside the cage that might prevent particularly large carts from being washed in the machine.

When the washing nozzles are positioned vertically, and a rotary movement to and fro in an angular range of about 90° is imparted to them during flushing, and the movement is performed in synchronism with the rotation, the wash¬ ing time may be reduced additionally, as all internal sides are effectively cleaned in this manner, since all internal sides will thus have the same washing time.

Finally, it is expedient that the device is recessed in a cavity m a floor, and that the device in the cavity is

supported by two rings of the same outside diameter, the first ring having an inside diameter which is smaller than the diameter of the second ring, and that the second ring is arranged on top of the first ring, said first ring being made of polyurethane, said second ring being made of soft polyurethane, which is desirable in particu¬ lar in connection with high centrifugation speeds, as the strongest vibrations are effectively damped hereby. The washer of the invention is adapted to run at centrifuga- tion speeds of at least 120 revolutions per minute.

The invention will now be explained with reference to an example shown in the drawing, in which

fig. 1 shows the washer of the invention in a first state of operation,

fig. 2 shows constructional parts which are incorporated in the washer,

fig. 3 shows the cage for mounting in the washer,

fig. 4 shows holding means which are arranged inside the cage of fig. 3,

figs. 5A-5F schematically show the movement of the spray¬ ing nozzles,

fig. 6 shows some additional constructional details of the washer, and

fig. 7 shows how the washer is arranged on a base.

In fig. 1 the washer of the invention is generally desig- nated 1. 2 and 3 designate slidable doors which are shown vertically displaced in fig. 1, thereby providing an

openmg on the both sides of the washer. As additionally shown in fig. 1, a cage 4 is arranged inside the washer, said cage being movable up and down together with the doors, as will be described later. A rotatable floor 7 is shown in the interior of the housing 1, and spraying nozzles 5, 6 are shown on inner walls of the housing, one spraying nozzle 5 being fixedly mounted, the other spray¬ ing nozzle 6 being movable, as will be explained more fully below. Further, two vertical rows of nozzles are provided for the final flushing, cf. the reference nu¬ meral 37. No further washing nozzles of the same type as the spraying nozzles 5 and 6 are shown inside the hous¬ ing. 8 designates a through shaft which connects a ro¬ tatable floor with a motor (not shown in fig. 1), which is mounted in the upper part of the housing 1. A compart¬ ment for the storage of detergents, electric motors and other control is provided to the left in fig. 1.

Fig. 2 shows the individual constructional parts of the washer of the invention in detail. As will be seen in fig. 2, it is indicated by arrows 10 that the cage 4 can rotate together with the floor 7. The rotation is pro ^¬ vided by a motor 12, which is capable of transferring a rotary movement to the cage via drive belts 19, 20, 21 and pulleys 17, 18 and 22. This rotary movement may be controlled at different speeds, as will be explained more fully below. Fig. 2 additionally shows pumps 14 and 16 which are arranged partly for pumping water into the washing nozzles 5, 6, cf. fig. 1. The pump 11 is the fi- nal flushing pump and is only in operation during the flushing period. Fig. 2 moreover shows a ventilator 30 which is adapted to suck vapour out of the machine during the drying process. Fig. 2 finally shows a door motor and a gear 13.

Fig. 3 shows in greater detail how catering carts to be washed in the washer are placed m the cage 4. As will be seen in fig. 4, two catering carts 23, 24 are shown, one of which is twice as large as the other. The catering carts 23, 24 are secured in the cage 4 by holding means which, as shown m fig. 4, consist of a slidable rod 25 and hooks 27. With the catering carts 23, 24 placed in¬ side the cage, the hooks 27 can engage over edges 19 on the catering carts. It is ensured in this manner that the carts do not rest against the wire net, which might have as a result that doors (not shown) of the catering carts could not be positively closed, and consequently that they could not be washed and dried on the rear side.

If catering carts are used in the cage which do not have an edge with which the hooks 27 can engage, spacers 28 are provided internally on two sides of the cage, and these spacers ensure that the carts cannot rest against the two walls of the cage.

The operation of the washer will now be explained.

With open doors 2, 3, i.e. in a state of operation where the cage 4 is displaced out of the housing 1, catering carts are placed inside the housing. Then the doors 2, 3 and the cage 4 are displaced downwards, thereby causing the hooks 27 to engage edges 19 on the catering carts 23, 24. The washing process cannot start until the doors have been closed completely, safety switches (not shown) being arranged to ensure that the actual washing process cannot be started until the doors 22, 3 have been closed com¬ pletely. It should also be mentioned that several safety arrangements are provided inside the housing 1 which en¬ sure e.g. that the cage 4 cannot be lowered if it e.g. meets with resistance for some reason, such as from the doors .

The washing process can now be initiated, and it consists partly of a wash with detergent, a flush with rinse aid, and partly of a subsequent drying with centrifugation and venting. The wash with detergent takes place at a first speed of rotation, and then the carts are accelerated to about 50-100 rpm for throwing excess soap, debris and reading matter out of the carts. This is followed by de¬ celeration to a first speed and final flushing with the pump 11. Finally, drying is performed where the speed of rotation is increased, and vapour is simultaneously sucked out of the machine. During the first flushing any objects left in the machine might be thrown out, but this will not have disastrous results, since such objects will be confined within the cage 4. It is therefore defensible to increase the speed of rotation somewhat at the subse¬ quent drying, since any objects left inside the catering carts have been thrown out. Further, the entire washing process typically takes from 3 minutes, which, however, depends on the centrifugal speeds used.

It is shown in figs. 5A-5F how the circular movement of the spraying nozzles 6 cooperates with the rotation of the catering carts 23. As will be seen in fig. 5A, a net 29 from the spraying nozzle 6 and the catering cart 23 in a first position are shown. It will be seen from fig. 5B that the jet 29 now sweeps one side of the catering cart 23 which has correspondingly moved a distance clockwise. It appears from the following figs. 5C-5F how the net can reach all sides inside the catering cart and clean the cart effectively, as the rotary movement to and fro of the spraying nozzle 6 is adapted to the rotary speed of the catering cart 23.

Fig. 6 schematically shows partly in sectional view how the various components are arranged inside the housing 1 in the washer. The figure e.g. shows the motor 12 which

drives the centrifugation, the ventilator 30 which sucks vapour out in order to provide rapid drying, and the pumps 11, 14 and 15.

As will be appreciated, a centrifugation at about 120 rpm, and with the radii which result m not insignificant g-values on the rotating parts, might cause vibrations, in particular if the centrifugation takes place at a cer¬ tain imbalance, which can normally not be avoided com- pletely. Therefore, the entire cage 4 is suspended loosely, but secured to the housing at the four corners at the top of the housing 1. The attachment is performed with a spring suspension so that any vibrations will be absorbed. The drive motor 12 is fixed so that these vi- brations cannot propagate to the electric motor. This mo¬ tor 12 is provided with an electromagnetic brake for the cage 4 and the machine base to be secured in a correct position during filling and emptying. Further, the hous¬ ing 1 of the washer is recessed in a floor which is shown in detail in fig. 7, and in which the washer is arranged in a depression 36. The base 32 and adjoining sides 36 of the washer are placed on two rings 34, 35, of which the outer ring 35 has a smaller mside diameter than the in¬ ner ring 34. The ring 35 is adapted to support the floor in the machine 32, while the ring 34 is adapted to absorb transverse vibrations from the machine. The two rings 34, 35 consist of soft polyurethane foam 34 and somewhat more rigid polyurethane foam 35, respectively.

Finally, it should be mentioned that the housing 1 itself is made of stainless steel plate, with foam plastics sandwiched therebetween, which additionally ensures that the sound level is kept at even very low values. This sandwich structure thus ensures optimum strength for the entire machine, without this resulting in a very great weight, and thereby optimum heat and noise insulation.

Although the principles of the invention have been ex¬ plained in connection with the cleaning of catering carts for aircraft, nothing, of course, prevents other objects from being washed in the machine, which is possible par¬ ticularly because no shaft extends through the central part of the washer.