Carcass Cleaning Method, Device and Machine

The present invention relates to a cleaning device for cleaning the surface of a carcass by contact, the cleaning device comprising a plurality of steam dis- charge jets and a suction nozzle. Further, the invention relates to a method for cleaning a carcass, to a combined nozzle arrangement, to a hose for the formation of the combined nozzle arrangement, and to a cleaning machine incorporating the cleaning device of the invention.

The carcass in question is in particular a carcass of a slaughtered animal to be cleaned during processing in a slaughterhouse, or similar.

In order to increase food safety, there is an increasing focus on minimising the risk of contamination of meat by e.g. bacteria. In recent years, a lot of effort and expenditure has been invested in reducing contamination of meat at slaughterhouses. Also, decontaminating or cleaning carcasses with steam to reduce visible contamination (e.g. dung) and non-visible contamination (e.g. bacteria) is being used to an increasing extent.

State of the art for carcass cleaning and decontaminating includes the suction head described in WO 03/026432. This suction head resembles a common hand shower, and the head comprises steam ducts arranged around a central suction air duct. The suction head is swept by hand over the surface to be cleaned, in contact with the surface. The suction head facilitates cleaning of carcasses for visible contamination, as it is easy to use for the operator, and the effect of the cleaning is impressive. Although this suction head represents a major progress, the cleaning process is relatively expensive, as it relies on manual operation of the suction head. Further, as it is a manual process, there is a risk that the operator will miss certain areas of the carcass or overlook contamination, and it is entirely left to the operator to decide which area of carcass surface to clean and indeed to sweep the suction head over the whole of this area. Contamination may also be invisible to the human eye. One object of the present invention is to provide a cleaning method enabling easy and thorough decontaminating and cleaning of the surface of a carcass with less manual operation and with no or less need for assessing or judging the type, degree and/or extension of contamination prior to cleaning.

To meet this object, the cleaning method according to the invention comprises the following steps:

- Discharging steam onto said surface from a plurality of steam discharge jets; and - Drawing in impurities, steam and condensate from the surface through a plurality of suction nozzles adapted to following an uneven surface of the carcass.

By the use of a plurality of suction nozzles, a large area of carcass surface may be covered at any one time, whereby the cleaning is made easier and an operator will not have to carefully clean specific, chosen portions of the carcass, but may just sweep the cleaning device over the carcass surface.

By adapting the suction nozzles to follow an uneven carcass surface, the need for careful (manual) moving of a suction head along the various shapes of the carcass may be eliminated.

By these measures, the cleaning process will become more efficient, both technically and economically.

As the cleaning method uses a plurality of steam discharge jets and a plurality of suction nozzles, the size and shape of the area of carcass surface cleaned simultaneously may easily be adapted to the needs by varying the number and arrangement of steam discharge jets and/or suction nozzles used. A particular advantage is that the method of the invention facilitates automation of the procedure of cleaning, in particular because an automated cleaning process will not need to comprise assessment of the nature or the spatial extent of the contamination.

The use of steam and suction will provide for a thorough decontamination for each steam discharge jet and suction nozzle in the manner known per se from the prior art.

It is preferred that the steam discharge jets and the suction nozzles are pressed against and/or swept across the carcass surface.

By this measure, the probability that all jets and nozzles contact the car- cass surface is increased - or contacting is assured - thereby providing for a thorough steam treatment of the whole surface and a thorough suctioning away of impurities, steam and condensate.

In a preferred embodiment of the method, the steam discharge jets and the suction nozzles are swept across the carcass surface by automated machinery. Hereby, an automated cleaning process is provided for, enabling automated cleaning of carcasses at e.g. a slaughter line in a slaughterhouse. In another aspect, the object of the invention is to provide a cleaning device for cleaning a surface of a carcass by contact with less manual operation and with no or less need for assessing or judging the type; degree and/or extension of contamination prior to cleaning.

To meet this object, the cleaning device according to the invention com- prises a plurality of steam discharge jets for discharging steam onto the surface of the carcass and a plurality of suction nozzles for drawing in impurities, steam and condensate from the surface, whereby the suction nozzles are adapted to following an uneven surface of the carcass.

Hereby corresponding advantages are obtained as stated with respect to the method of the invention.

As the cleaning device comprises a plurality of steam discharge jets and a plurality of suction nozzles, the size of the cleaning device - that is, the area of carcass surface covered by the device at any one time - may easily be adapted to the desired cleaning process by varying the number of steam discharge jets and suction nozzles.

A particular advantage is that the invention facilitates automation of the procedure of cleaning, in particular because an automated cleaning device will not need to comprise features enabling assessment of the nature or the spatial extent of the contamination. The suction nozzles and/or steam discharge jets may be adapted for following the surface of the carcass in various ways, and according to a preferred embodiment, at least some of the suction nozzles are adapted to deflect resiliently when pressed against or swept over the carcass surface.

By this measure, the suction nozzles will automatically adapt to an uneven carcass surface. This is important, as practically the entire surface of a carcass is more or less uneven. Very few surface parts of a carcass indeed may be satisfactorily approximated by surfaces which are regular in a mathematical sense.

When the cleaning device is pressed against or swept over a carcass surface, the suction nozzles opposite protruding parts of the carcass surface will deflect more than suction nozzles opposite retracted or hollow parts of the surface, and this will enable that the cleaning device may be pressed further against the carcass, until the suction nozzles opposite retracted or hollow parts of the surface will actually contact these parts of the surface.

It is hereby achieved that all suction nozzles may come into proper contact with the carcass surface just by pressing the device against the carcass surface or sweeping it along the surface whiie maintaining surface contact, thus enabling thorough cleaning of the whole surface without the need for guiding the cleaning device along the carcass surface in a precise or delicate manner.

The suction nozzles may comprise additional openings or cut-outs for entry of ambient air arranged at or near a mouth of each suction nozzle.

In general, when the mouth of a nozzle is pressed against a surface, the nozzle may become choked or blocked, so that no air will enter the nozzle even if ample suction is provided. When the nozzle is choked this way, the air stream into the nozzle may become so weak that it has not the required force or capacity to carry impurities away from the surface in an efficient manner.

When openings or cut-outs are provided, ambient air will be drawn in, pro- viding for a sufficient air flow to carry impurities away from the carcass surface, even if the suction nozzle is abutting the carcass surface along its entire circumference.

At least a carcass-contacting mouth portion of each suction nozzle is preferably made from a flexible material, preferably silicone rubber. When the suction nozzles, or at least a mouth portion thereof, are made from a flexible material, they will become able to adapting to an uneven surface, such as the surface of a carcass to be cleaned, by deflecting or deforming. Hereby it is attained that all suction nozzles may touch the carcass surface at any one time, thus providing for efficient cleaning. If the suction nozzles do not have suitable flexibility, nozzles touching protruding parts of the carcass surface may lift the cleaning device so high that other nozzles are indeed lifted from retracted portions of the surface. In this case, the latter nozzles may not clean the corresponding parts of the surface in an efficient manner.

Silicone rubber or silicone-based materials are found to provide excellent results for this purpose as they are relatively cheap, very suitable for use with foodstuffs, and highly flexible.

According to the invention it is preferred that a number of steam discharge jets and suction nozzles are integrated into a combined nozzle arrangement.

Supply of steam onto the carcass surface is important, as the steam will at the same time loosen impurities and dissolve or disperse them into the steam flow and, by its very temperature, kill bacteria and micro-organisms.

By providing steam discharge jets in the immediate vicinity of the suction nozzles when these are incorporated into a common or combined nozzle arrangement, an ample and efficient supply of steam is provided, and the steam is applied to the carcass surface where it is needed, that is, near each suction nozzle.

In a preferred embodiment, the cleaning device has a plurality of such combined nozzle arrangements. Hereby, the cleaning device may be adapted to cover a desired area of carcass surface, and cleaning devices having different area coverage and indeed different shapes may be manufactured for different cleaning purposes. For instance, a hand-held cleaning head may be made, covering a small area; an elongated cleaning head for a cleaning machine may be made for sweeping along a carcass surface in a direction transverse to its direction of extension; and a curved cleaning head may be made, particularly adapted to cleaning a specific, curved part of a carcass.

In another aspect, the invention relates to a combined nozzle arrangement comprising at least one steam discharge jet and at least one suction nozzle. As mentioned above, it is advantageous to combine a number of steam discharge jets and suction nozzles into a combined nozzle arrangement for use in a cleaning device according to the invention.

According to the invention, the combined nozzle arrangement is preferably adapted to deflect resiliently when subjected to a force in a direction substantially transversely to the direction of the suction nozzle, and/or to give way or compress resiliently when subjected to a force in or in parallel with the direction of the suction nozzle.

By these measures, similar advantages are attained as explained above with respect to the cleaning device of the invention.

Preferably, at least the mouth of the suction nozzle is in the combined nozzle arrangement made from silicone rubber. By these measures, similar advantages are attained as explained above with respect to the cleaning device of the invention.

In a preferred embodiment, the combined nozzle arrangement is adapted to deflect considerably more when subjected to a force in a first direction substantially transversely to the direction of the suction nozzle or suction nozzles than in a second direction substantially transverse to the direction of the suction nozzle or suction nozzles, transversely to said first direction.

This will eliminate or obviate a tendency of the combined nozzle arrangements to deflect sideways around a protrusion of the carcass surface when the cleaning device is swept over the carcass surface, instead of moving over the pro- trusion. In this way, it is ensured that the surface of the protrusion will be cleaned properly.

It is preferred that the combined nozzle arrangement comprises at least six steam discharge jets and one central suction nozzle.

It is preferred as well that the combined nozzle arrangement constitutes a portion of hose with the suction nozzle arranged substantially centrally as the lumen of the hose and the steam discharge jet or jets arranged in a wall portion of the hose.

Further, it is preferred that the combined nozzle arrangement is made from a hose with a uniform cross section along its length, and that the suction nozzle and the steam discharge jet or jets are provided by cutting off the hose at a desired length.

By these measures, a very simple and cost-efficient nozzle arrangement is obtained, as nozzle arrangements may be manufactured by simply cutting the hose described into suitable lengths. In a particular embodiment of the combined nozzle arrangement, the suction nozzles may have additional openings or cut-outs arranged at or near the nozzle for entry of ambient air into that suction nozzle.

By this measure, similar advantages are attained as explained above with respect to the cleaning device of the invention.

When the nozzle arrangements are made from lengths of a continuous hose, the cut-outs may simply be cut in the end face of the length of hose. It may well be, however, that the nozzle arrangements are more advantageously made by injection moulding, whereby finished nozzle arrangements may be produced in one moulding process, including suction nozzles, steam jets, cut-outs, and possibly means for fixing the combined nozzle arrangement to the cleaning device.

In the particular embodiment mentioned, it is preferred that at least some of the mouths of the steam discharge jets open into an end-face of the combined nozzle arrangement, between said additional openings or cut-outs.

This will provide for the steam discharge jet mouths coming in good contact with the carcass surface so that the steam will not easily escape into the suction nozzle or the surroundings, respectively, before it reaches the carcass surface. It is thus ensured that a sufficient steam supply to the surface is maintained.

In a further aspect, the invention relates to a hose for the formation of a combined nozzle arrangement. According to the invention, the hose has a central lumen and a number of narrow channels embedded into the hose wall. The hose is preferably made from silicone rubber by extrusion. These measures provide for a hose by means of which the combined nozzle arrangements may be manufactured in a very simple and cost-efficient manner, and which will provide the nozzle arrangements with adequate resiliency.

The combined nozzle arrangement made from the hose may have the same advantages as explained above with reference to the combined nozzle ar- rangement in general.

In a last aspect, the invention relates to a cleaning machine for a carcass, incorporating a cleaning device according to the invention, as well as machinery for sweeping said device across a surface of a carcass.

By incorporating the cleaning device of the invention into a carcass clean- ing machine, the slaughter line operators may be further relieved from strenuous, manual work.

Such a cleaning machine lends itself well to being partly or fully automated, thereby eliminating partly or fully the need for personnel for performing or supervising the cleaning process.

Preferred embodiments of the present invention will now be explained in more detail with reference to the drawings, in which:

Fig. 1 is a schematic drawing in perspective of a cleaning device according to the invention;

Fig. 2 is a schematic cross-sectional view of a hose for the formation of a combined nozzle arrangement according to the invention; Fig. 3 is a schematic drawing of a prototype of a hand-held cleaning device according to the invention during use;

Figs 4-6 are schematic drawings in perspective of mouth portions of combined nozzle arrangements according to the invention;

Fig. 7 is a schematic cross-sectional view of a particular embodiment of a combined nozzle arrangement according to the invention; and

Fig. 8 is a schematic drawing in perspective of an automated carcass cleaning machine comprising a cleaning device according to the invention.

The schematic drawing of Fig. 1 illustrates a relatively simple prototype of a cleaning device 1 according to the invention. The device 1 has the form of a box having a vacuum manifold 7, which may be connected to a vacuum source (not shown) via a vacuum connector 15 and a vacuum line (not shown). Arrow 19 indicates the direction of suction air flow. The device 1 further comprises a steam manifold 8 having a steam connector 6 for a steam line (not shown), for supply of steam from a steam source (not shown). Arrow 5 indicates the direction of steam flow. A base plate 9 of the device 1 carries six combined nozzle arrangements 14. In this embodiment, the base plate 9 is constituted by a wall of the steam manifold 8. The combined nozzle arrangements 14 are made in the form of short lengths of hose 16 having a cross section as illustrated in Fig. 2. The hose 16 thus has a wall 13 surrounding a hose lumen 17, and eight narrow, peripheral channels 4 extending in the wail 13 of the hose 16, in parallel with the lumen 17.

In Fig. 1 , each combined nozzle arrangement 14 has a free end or mouth 12, which is simply constituted by the distal end of the length of hose. The nozzle arrangement mouth 12 has one central suction nozzle 2, constituted by the

distal end of the hose lumen 17, and eight peripheral steam discharge jets 3, constituted by the distal ends of the steam channels 4.

Each central suction nozzle 2 (corresponding to the lumen 17 of the hose 16) is in communication with the vacuum manifold 7 via internal tubing (not shown) in the cleaning device body. All peripheral steam discharge jets 3 are in communication with the steam manifold 8.

Steam from a steam supply line (not shown in Fig. 1) enters the steam manifold 8 via the steam connector 6 as indicated by arrow 5. From the steam manifold 8, the steam flows via the steam channels 4 and exits the steam discharge jets 3, which in the embodiment shown are constituted by the ends of the steam channels 4, at the mouth 12 of each nozzle arrangement 14. The steam pressure is controlled so that a desired steam flow (or pressure or temperature) is obtained out through the steam discharge jets 3. The steam may be superheated if a higher temperature is needed or desired. At present, it is generally preferred that the steam pressure and the vacuum are adjusted such that steam escapes into the surroundings when the cleaning device 1 is not in contact with the carcass surface, whereas there is no visible escape of steam when the device is in abutment with the carcass.

A vacuum line (not shown in Fig. 1) from a vacuum source is connected to the vacuum connector 15, which is via internal tubing (not shown) connected to each suction nozzle 2. Thus, ambient air is drawn into the suction nozzles 2 and via hose lumens 17, vacuum manifold 7 and vacuum line to an impurities collection tank or similar. The air draws excess steam, steam condensate and any impurities from the carcass surface into the suction nozzles 2 and further along to the impuri- ties collection tank.

The treated surface is left clean and in most cases even sterilised. Further, the treated surface is left substantially dry, or at least without any additional moisture from the cleaning process.

As the hose 16 is made from a flexible or highly flexible material such as silicone rubber, the combined nozzle arrangements take the form of flexible 'fingers' which may deflect when they are held or pressed against the surface of a carcass body, as shown in Figs 3 and 8.

Referring now to Fig. 3, a hand-held prototype of the cleaning device 1 is shown in use during cleaning of the inside of a pig half-carcass 10. In the embodiment shown in Fig. 3, the cleaning device 1 is adapted for manual use by an operator in that it has two handles 11. In this embodiment, the cleaning device has an array of 4 * 3 combined nozzle arrangements 14 or 'fingers', like the embodiment shown in Fig. 1.

Steam is supplied to the steam manifold 8 via a steam line (not shown) and further on to the steam discharge jets in the hose walls at the combined nozzle arrangement mouths 12. Vacuum is applied to the vacuum manifold 7 from a vacuum line 20 via a vacuum connector 15. Corresponding suction air is drawn into the suction nozzles 2 from the carcass surface environment at the mouths 12 of the combined nozzle arrangements 14.

In the use shown in Fig. 3, the cleaning device 1 is thus held with its com- bined nozzle arrangement mouths 12 against the carcass surface to be cleaned, and is preferably swept across the surface in order to subject a desired surface area to the cleaning treatment. During sweeping, the device 1 is pressed against the surface with suitable, but not excessive force so that the combined nozzle arrangements 14 or 'fingers' abutting high or raised areas of carcass surface are deformed or deflected to a certain degree as it appears from Fig. 3. This will ensure that the fingers opposite retracted or hollow areas of carcass surface will be able to reach and abut these areas by not being deformed, or being deformed to a smaller degree.

In this respect, the cleaning device 1 works in a similar manner as a brush or a broom.

Steam escaping at a desired, suitable pressure and temperature from the steam discharge jets 3 hits the carcass surface where it loosens and dissolves impurities, etc., and also sterilises the surface to a certain degree. The air entering the suction nozzles 2 at a flow rate corresponding to i.a. the level of vacuum in the vacuum manifold 7, draws the loosened and/or dissolved impurities, etc., into the suction nozzles 2, from where they are transported via the vacuum line 20 to an impurities collection tank or similar. Steam, condensate and any excess moisture is drawn in as well.

In this way, it is ensured that every portion of carcass surface swept over by the nozzle arrangement mouths 12 will be thoroughly cleaned and disinfected.

Alternatively to a comparatively small, plane, rectangular base plate 9 as in the cleaning devices 1 illustrated in Figs 1 and 3, the base plate 9 may be curved and/or sized to match desired parts of a carcass to be cleaned, for example convex for cleaning the inside of a carcass, such as at the pelvic region, or concave to match a convex outer surface of e.g. a ham.

Hose-type steam discharge jets were tested in a prototype of the cleaning device of the invention. For the prototype, a hose 16 made by extrusion from a silicone rubber of VMQ-type sold as "Biosil 31399" by the company Asicomo was used for making the combined nozzle arrangements 14. This particular type of silicone rubber is transparent, peroxide-cured and food-contact approved, and has a standard-hardness of 60° ± 5° Shore A.

The hose 16 was circular in cross-section with an outer diameter of ap- proximately 21 mm, and a central lumen 17 having an internal diameter of approximately 13 mm. In the wall of the hose, eight peripheral steam channels 4 having an internal diameter of approximately 1.5 mm were provided. The steam channels 4 were spaced equally apart across the entire perimeter of the hose wall, as seen in cross section. The hose 16 was cut into lengths of approximately 70 mm, which were used ^" as combined nozzle arrangements 14. The combined nozzle arrangements 14 were mounted on the base plate 9 of a cleaning device 1 in such a way that the lumen 17 of each hose was connected to the vacuum manifold 7 via internal tubing, and all steam channels 4 were connected to the steam manifold 8 in the cleaning device 1.

Fig. 2 is a schematic view, not to scale, of the above-mentioned type of hose 16, and thus at the same time illustrating the structure of the embodiment of the combined nozzle arrangements just mentioned. This hose 16 has a lumen 17 surrounded by a hose wall 13, and eight peripheral steam channels 4 embedded into the hose wall. The corresponding, combined nozzle arrangement 14 comprises a central suction nozzle 2, constituted by the distal end of the length of hose and surrounded by the hose wall 13. Further, the combined nozzle arrangement 14 has

in this embodiment eight steam discharge jets 3, constituted by the openings of the peripheral steam channels 4 where the hose 16 has been cut.

This particular, circular embodiment of the nozzle arrangement 14 is only one possible form of nozzle arrangement. Particular cross-sectional shapes of combined nozzle arrangements may be advantageous for use in cleaning devices 1 for particular cleaning purposes. For example, if the cleaning device 1 is only to be swept across the carcass surface in one direction, it may be advantageous to provide the combined nozzle arrangements 14 with an oval or D-shaped cross section, in order that the flexibility of the nozzle arrangements may be increased in the direc- tion in question while maintaining a maximum cross-sectional area of the suction nozzle 2.

In addition, the mouth of the combined nozzle arrangements 14 may be cut off at a sloping angle rather than at right angles as shown in the drawing figures, for use for particular purposes. With reference to Figs 4 to 6, the mouth of the combined nozzle arrangement 14 may be provided with openings or cut-outs 18 for entry of ambient air.

Fig. 4 shows the distal portion of a combined nozzle arrangement 14 of the embodiment described above and shown in Figs 1-3. It is evident that if the mouth 12 of this nozzle arrangement abuts a plane surface along its entire circum- ference, both the steam discharge jets 3 and the suction nozzle 2 may become blocked. Even if this situation may not happen very often during practical use, the consequences may be that a corresponding portion of carcass surface will not receive sufficient steam and will not have impurities, etc., removed to a satisfactory extent. In particular, the air flow into the suction nozzle 2 may be choked so much that it is insufficient to carry away the impurities, etc., collected from the carcass surface, and this may lead to re-contamination of cleaned areas of carcass surface.

In Fig. 5, eight V-shaped cut-outs 18 have been made in the end face 28 of the hose wall 13, in-between the steam discharge jets 3. During use, air will enter from the carcass surface environment into the suction nozzle 2 via the cut-outs 18 and keep the air flow into the nozzle above a certain minimum level. In the embodiment in Fig. 5, there is still the risk of the steam discharge jets 3 being choked if the combined nozzle arrangement 14 is brought into complete abutment with a plane

carcass surface, and this may block the steam discharge jets 3, depending on the steam pressure and the abutment force.

In Fig. 6, eight similar V-shaped cut-outs 18 have been made in the end face 28 of the hose wall 13, but coinciding with the steam discharge jets 3. That is, the steam discharge jets 3 open into the cut-outs 18. This will ensure that steam will always discharge from the steam discharge jets 3, irrespective of the abutment of the combined nozzle arrangement 14 on the carcass surface, and the air flow into the suction nozzle 2 is maintained in the same way as explained with reference to Fig. 5. Experiments have however shown that the reduction in microbiological contamination is better using the combined nozzle arrangement 14 in Fig. 5 than the one in Fig. 6. This is believed to be due to the fact that in Fig. 6, the steam discharge jets 3 open at a distance from the carcass surface so that the steam is not directed onto the carcass surface as efficiently as in the embodiment in Fig. 5. Also, in the embodiment in Fig. 6, the flow resistance from the steam discharge jets 3 into the suction nozzle 2 is very small, and it is believed that this will tend to make the steam treatment less efficient because too much steam will escape from the steam discharge jets 3 directly into the suction nozzle 2 without reaching the carcass surface. In all the embodiments of Figs 2 and 4-6, it may according to the invention be advantageous to cut or chamfer the cut-outs 18 and/or the end face of the hose wall 13 in such a way that the steam discharged from the steam discharge jets 3 will meet less resistance when discharging into the space outside the hose wall 13 than when discharging into the lumen 17 of the hose, that is, into the suction nozzle 2. The vacuum in the suction nozzle 2 may tend to draw so much of the discharged steam into the suction nozzle 2 that only a too small fraction of the steam will eventually reach the carcass surface. If this situation arises, it may be advantageous to choke the flow path leading directly from the steam discharge jets 3 to the suction nozzle 2. This may be done by appropriate chamfering or cutting of the cut-outs 18, and the skilled person will be able to perform appropriate experiments for determining the details in this respect on the background of the explanations in the present disclosure.

Experiments have further shown that combined nozzle arrangements or 'fingers' 14 having a generally circular cross section like the ones shown Figs 1-6 may have a disadvantageous tendency to deflect sideways relative to the direction of sweep of the cleaning device 1 across the carcass surface. That is, if the clean- ing device 1 is swept across a high (protruding) point of the carcass surface, the combined nozzle arrangements 14 or 'fingers' may tend to deflect sideways and thus move around the high point instead of over it. In this case, the high point of carcass surface may not be subjected to the desired degree of cleaning.

In order to obviate this tendency of the fingers to deflect sideways, fingers having oval or D-shaped cross section may be used. Alternatively, the embodiment shown in Fig. 7 of a combined nozzle arrangement 21 may be used. In the latter embodiment, a number of combined nozzle arrangements 14 of the type explained above and illustrated in Fig. 2 have been interconnected by means of flexible walls 22, thus forming the combined nozzle arrangement 21 having three suction nozzles 2 and 24 steam discharge jets 3. The combined nozzle arrangement 21 has an intended direction of sweep as indicated by arrow 23. The interconnections 22 will not influence the ability of the "fingers' 14 to deflect in the direction 23 of sweep, while they will reduce very markedly the ability of the fingers 14 to deflect transversely to the direction 23 of sweep. Hereby, the tendency of the fingers 14 of the combined nozzle arrangement 21 to deflect sideways around a protruding carcass surface part may be eliminated to a satisfactory degree. This configuration of the combined nozzle arrangement 21 will also lend itself well to being manufactured by extrusion.

The interconnections 22 will however reduce the ability of each finger 14 of the combined nozzle arrangement 21 to deflect independently of the other fingers 14 of the combined nozzle arrangement 21 in the direction 23 of sweep.

It is believed that a compromise between the disadvantages mentioned above may be achieved by varying the thickness of the interconnections 22, by removing the interconnections 22 from distal portions of the fingers 14 or by other variations of the mechanical characteristics of the interconnections 22.

In general, good results have been achieved using saturated steam at a pressure of 1 to 2 bar, measured at the beginning of a flexible steam supply line (27), that is, one or two metres from the cleaning device 1 , and a suction vac-

uum of 0.2 to 0.3 bar, measured in the impurities collection tank, which may be connected to the cleaning device 1 via 10 to 15 metres of piping.

Two tests have been carried out with different configurations of the combined nozzle arrangements 14 made from the hose having the cross section illus- trated in Fig. 2, and with different operational variables, as outlined in the following table:

Both tests showed good results in reduction of bacteria. Fig. 8 shows an experimental prototype of an automated cleaning machine for cleaning an outer surface portion of a pig half-carcass 10. In the figure, two pig half-carcasses 10 are hanging from a gambrel (not shown). An experimental robot 24 having at least two directions 25 of linear movement is mounted near the station where the carcass is hanging, and a cleaning device 1 according to the

invention has been mounted on the robot's arm 26. A steam supply line 27 and a vacuum line 20 have been connected to the cleaning device 1.

The robot 24 is now able to sweep the cleaning device 1 across the outer surface of the near half-carcass 10 in at least the two directions 25, and a third direction may be added without any difficulty. Experiments have shown very satisfactory results from this prototype automated cleaning machine.

Although the illustrated and described embodiments of the cleaning device 1 of the invention are all relatively small, the skilled person will understand from the present disclosure that the size and shape of the cleaning device may be varied according to various needs. For example, the cleaning device may be sized to cover the outer surface of a half-carcass, preferably in one dimension thereof for being swept or 'scanned' across the carcass half along another dimension. In that case the cleaning device may clean the outer surface of a complete carcass half by simply sweeping the cleaning device once along the outer surface of the carcass half.

Suitable values for the flexibility or resiliency and length of the nozzle arrangements may depend on the particular use and they may be established without undue effort by the skilled person by experiment. The skilled person will realise that the flexibility of the nozzle should be chosen between the extremes of a very flexible and a very rigid embodiment.

The very flexible embodiment increases the risk that the nozzles will deflect to a degree in which the cleaning and decontamination rendered by the steam discharge jet is ineffective as the mouth of the nozzle arrangement will disengages the surface to be cleaned, in particular at projecting parts of the surface. On the other hand, a very rigid embodiment increases the risk that the nozzles will not adapt to the surface to be cleaned, so that only projecting or non-concave portions of the surface will become in appropriate engagement with the nozzle arrangements.

It will further be possible for the skilled person to vary the size, number and distribution of nozzle arrangements to provide the best results for any particular application of the cleaning device of the present invention.

List of Reference Designations

1 cleaning device

2 suction nozzle

3 steam discharge jet

4 peripheral steam channel

5 steam flow direction

6 steam connector

7 vacuum manifold

8 steam manifold

9 base plate

10 carcass

11 handle

12 mouth of combined nozzle arrangement

13 hose wall

14 combined nozzle arrangement

15 vacuum connector

16 hose

17 hose lumen

18 cut-out

19 suction air flow direction

20 vacuum line

21 combined nozzle arrangement

22 flexible wall

23 direction of sweep

24 robot

25 directions of movement

26 robot arm

27 steam supply line

28 hose wall end face