GB2528282A

GB2528282A - Sterilisers

Info

Publication number: GB2528282A
Application number: GB1412619.7A
Authority: GB
Inventors: Neil Knight; Paul Hughes
Original assignee: SISTERS RED MEAT Ltd 2
Current assignee: SISTERS RED MEAT Ltd 2
Priority date: 2014-07-16
Filing date: 2014-07-16
Publication date: 2016-01-20
Also published as: GB201412619D0

Abstract

A steriliser comprising a housing SH in which an article to be sterilised is locatable and a hot water bath to sterilise an article located in the housing, the housing having an open top to allow articles to be stowed in and removed from the housing, the steriliser having a cowl 1 located over the open top, the cowl 1 having a top wall 5, side walls 3, 4 and a front and back wall 7, 6, wherein the front wall 7 comprises an opening 8 through which articles are locatable in and removable from the housing and in use steam or vapour escaping from the housing condenses or is able to condense on one or more of the cowl walls. The front wall of the cowl may extend outwardly from the front edges of the side and top walls. The front wall may comprise a central portion 7c bound on either side by a peripheral portion 7p, each peripheral portion being connect to a respective side wall. The top wall may be curved, slanted or tapered direct condensed water via gravity towards a lowermost portion. The steriliser is suggested for use in abattoirs and meat processing for sterilising knives.

Description

Ste ri Ii s e rs This invention relates to sterilisers and, more particularly, although not exclusively, to hot water sterilisers.

It is known to sterilise using hot water. Other steriliser units use ultra violet light and/or chemical sterilisation agents.

Hot water is a very useful sterilising agent because it is very effective, easily generated, non-toxic and uses relatively cheap materials (water and energy). It is also possible to use steam to sterilise articles. Whilst this may have a higher sterilisation potential, it may be more expensive to generate and is not necessary in many circumstances.

Accordingly in many instances hot water sterilisation is the method of choice. Indeed it is believed that hot water sterilisation is the most commonly used technique in the sterilisation of articles used in food, e.g. meat, production.

One known use of hot water sterilisation involves the sterilisation of knives in a butchers or meat processing plant. Typically a body of hot water is heated to in excess of 82°C and the blade of a knife located in the body of water to effect sterilisation.

Meat processing plants are typically cold, for example between 0 and 12°C. Usually there are plural stations at which butchers or other operatives dress the carcass of an animal. At each of such stations there may be provided one or more knife sterilisers.

The knife steriliser may comprise a housing holding the body of water which is heated and, as a consequence, produces steam. The housing also includes a rack in which knives can be stowed to allow the hot water to sterilise the blade and handle. An operative will typically have one knife in the steriliser whilst he uses another knife.

A prior art steriliser is shown in GB2506168. In order to inhibit steam egress from the housing a hinged lid is provided. The lid is lifted to allow access to the interior of the housing; for example to stow or remove a knife, and closed at other times.

As stated above, meat processing plants are typically cold and so steam which leaves the steriliser unit to enter the wider environment will rapidly condense on walls or other surfaces. This is problematic because it can lead to the growth of mould, damage to the factory and/or drips of condensed liquid falling onto or into the or a product being processed.

Many countries around the world have regulations which govern the conditions in which food and food products are produced. In Europe, Regulation No 852/2004 is in force. This regulation states "Food businesses shall put in place implement and maintain a permanent procedure or procedures based on the Hazard Analysis and Critical Control Point (HACCP) Principles". Thus, it is necessary for managers of sites to ensure that steam egress from steriliser units is managed assiduously. Typically, steam management is dealt with by strictly enforcing the closure of lids on units and by the rapid and frequent removal of condensed steam from the factory environment. As will be appreciated, it is impossible to obviate steam egress entirely because steam will escape when the lid is lifted. This ensures that significant effort in terms of man-power effort is deployed and cost is incurred to remove condensed steam. That said, it is difficult, if not impossible, to deploy sufficient human resource to remove steam as soon as it condenses on a surface.

It is also known in such plants that each steriliser unit has often to be topped up with fresh, typically cold, water. This is wasteful of both water and energy and is further wasteful of man-power: it is inefficient.

Moreover, operatives are encouraged to store a first knife in a steriliser unit whilst the operative works with a second knife. The two knives may be transferred when a task is concluded. For example, an operative may be required to use a first knife to cut through the hide of an animal and a second knife to joint or dress a carcass. Thus the first knife will be placed in the steriliser after the hide has been cut and the second knife removed from the steriliser to dress the carcass and then the two swapped again for use on a succeeding carcass. This reduces the likelihood of cross contamination. Moreover, in a boning hall there may be a requirement to change the working knife after a certain period of use (for example after ten minutes use) or at other times when the knife becomes dirty or otherwise contaminated. As such, there are many "lid lifts" during a working hour. Cf course in a typical processing plant there will be many operatives and, consequently, many sterilisers.

Therefore, even where extreme care is taken to maintain a closed lid at all possible times steam egress will occur.

As will be appreciated, even with the most stringent controls and with operatives always remembering to close lids there is a problem with steam egress and this may be exacerbated if or when operatives do not deploy all due care.

It is an object of the current invention to at least partially mitigate the problems associated

with the prior art.

In a first aspect of the invention there is provided a steriliser comprising a housing in which an article to be sterilised is locatable and hot water generating means to generate hot water to sterilise an article located in the housing, the housing having an open top to allow articles to be stowed in and removed from the housing and through which steam generated in the steriliser is free to escape the housing, the steriliser having a cowl located over the open top, the cowl having a top wall, side walls and a front and back wall, wherein one of the front, back and side walls comprises an open aperture through which articles are locatable in and removable from the housing and in use steam escaping from the housing condenses on one or more of the top wall, side walls, back wall and front wall.

The top wall comprises a condensation surface which may be shaped so as to encourage or cause water condensed thereon to run or drip into or towards the housing.

The condensation surface may be curved, slanted or tapered. Preferably the condensation surface may have an uppermost portion and a lowermost portion, the uppermost portion being further from the open top than the lowermost portion.

The lowermost and uppermost surfaces are preferably contiguous so as to allow or cause water condensed on the uppermost surface to run, or flow onto the lowermost surface.

The condensation surface may comprise depending protrusions from which condensed water may drip into the housing.

In a preferred embodiment the condensation surface is curved with a substantially centrally disposed part and peripheral parts, the centrally disposed part of the condensation surface being substantially above the centre of the open top.

The peripheral parts of the condensation surface may be disposed substantially above peripheral parts of the open top. Most preferably the peripheral parts are disposed outboard of a nominal vertical plane defined by the boundary of the open top. The centrally disposed part may comprise the uppermost portion. The or a peripheral part may comprise the lowermost portion.

Preferably the condensation surface is joined to the side walls at a smooth transition, the angle between the condensation surface and the side walls being non orthogonal.

Advantageously this allows water condensed on the condensation surface to run from that surface onto the side walls, and preferably down the side walls to or at least towards the open top.

Preferably the top wall and side walls define an at least partially circular body. Preferably each of the side walls terminates in a funnel portion.

The front wall preferably comprises the aperture. The front wall preferably extends from the side walls and top walls.

Preferably to front wall bulges outwardly from the side walls.

In a preferred embodiment the side walls each have a rear edge and a front edge, the front wall of the cowl being attached or joined to the front edge of each side wall and the rear wall being attached or joined to the rear edge of each side wall.

The front edges of the side walls together define a nominal front plane. Preferably the front wall extends outboard of the nominal front plane.

In a preferred embodiment the front wall curves outwardly and way from the front edges to form a hood portion.

As will be appreciated the steriliser of the invention provides means to trap steam egressing from the open top of the housing, thereby obviating problems associated with steam release, whilst also providing a large opening to allow operatives to place articles in, and remove articles from, the housing.

Preferably the nominal front plane is defined between the front edges of the side walls and the or a front edge of the top wall. The nominal front plane may have a surface area A. When viewed in a direction normal to the nominal front plane the front wall may overlie a portion, but not all, of the nominal front plane, thereby to provide the aperture.

Preferably the front wall has a surface area AFW and AFW < A, preferably AFW «= O.75A, for example A «= 0.7, 0.6, 0.5, 0.4, O.3A and is greater than 0.05A, preferably greater than O.1A.

In the case where the steriliser is used to sterilise knives, the construction is particularly advantageous. For example, the (preferably) large opening allows knives with long blades to be safely deposited and removed from the housing whilst removing operative effort in relation to raising and lowering the lid of prior art systems. Moreover the cowl, being of relatively large external suiface area as a proportion of its volume, provides an efficient heat exchange surface. This ensures that the outer surfaces of the cowl remain at or approaching room temperature and the inner surfaces provide effective condensation surfaces. The condensation of steam and the flow back of the condensed water to the steriliser ensures that refilling the supply of water within the housing is reduced.

A further aspect of the invention provides a cowl for use with a steriliser, the cowl comprising an open base portion for operative engagement with the open top of a steriliser and through which, in use, steam escaping from the steriliser is able to enter the interior volume of the cowl, the cowl fuither comprising an opening through which in use, items are depositable in and removable from the steriliser through the open top, the cowl having a condensation surface locatable over the open top of the steriliser, wherein the condensation surface has a surface area greater than that of the open top.

A yet further aspect of the invention comprises a meat processing plant having plural stations where an animal carcass is butchered, jointed or dressed, each station having at least one steriliser unit comprising a housing in which an aiticle (ag. a knife) to be sterilised is locatable and sterilising means to sterilise an aiticle located in the housing, the housing having an open top to allow articles to be stowed in and removed from the housing and through which steam generated in the steriliser is free to escape the housing, the steriliser having a cowl located over the open top, the cowl having a top wall, side walls and a front and back wall, wherein one of the front, back and side walls comprises an open aperture through which articles are locatable in and removable from the housing and in use steam escaping from the housing condenses on one or more of the top wall, side walls, back wall and front wall.

In order that the invention may be more fully understood reference is made, by way of example only, to the accompanying drawings, in which Figure 1 is a front elevation of a steriliser cowl according to the invention; Figure 2 is a side elevation of the cowl of Figure 1; Figure 3 is a view from below of the cowl of Figure 1; and Figure 4 is a second embodiment of a steriliser according to the invention.

Referring to Figures 1 to 3 there is shown a cowl 1 having an open base portion 2, a first side wall 3, a second side wall 4, a top wall 5, a back wall 6 and a front wall 7.

The open base portion 2 is substantially rectangular and is defined by lowermost portions of the side walls 3, 4 and back wall 6. Each of the side walls 3, 4 and back wall 6 may be provided with a flared extension portion 3a, 4a, 6a respectively to allow the cowl 1 to sit on the open top of a steriliser housing SH. The extension portions 3a, 4a, 6a may be integral with or attached to the respective wall 3, 4, 6.

The side walls 3, 4 curve outwardly and upwardly away from the base portion 2 and join to the top wall 5 in a smooth transition to form a curved, preferably circular. whole.

The side walls 3, 4 and top wall 5 are each joined to the back wall 6 which totally or substantially closes the cowl 1 between the side walls 3, 4 and top wall 5 at the rear thereof.

The side walls 3, 4 and top wall 5 have front edges 3f, 4f, Sf respectively and rear edges 3r, 4r, Sr respectively. The front wall 7 is joined to and extends outwardly and away from the front edges 3f, 4f, Sf of the side walls 3, 4 and the top wall 5 to form a crescent-shaped hood or peak to leave a large aperture 8.

The front edges 3f, 4f, St of the side walls 3, 4 and top wall 5 together define a nominal plane P. The front wall 7 has a central portion 7c bounded one either side by a peripheral portion 7p. The front wall has a distal edge 7e.

The front wall 7 bulges outwardly of the nominal plane P such that the distal terminal edge 7e of the central portion 7c of the front wall 7 is further from the nominal plane P than any other part of the front wall 7, for example each peripheral portion 7p.

We prefer that the maximum dimension y of the terminal edge 7e from the nominal plane P is 0.5 to 1.5 times the distance x from the nominal plane P to the back wall 6, and preferably y is from 0.6x to 1.3x, say 0.7x to 1 Ox.

The area of the nominal plane P defined between the front edges 3f, 4f, Sf has an area A. When viewed in a direction orthogonal to the nominal plane P (e.g. in the direction of arrow I in Figure 2) the front wall 7 will preferably cover a minor proportion of the area A (Le.

less than 0.5A), most preferably less than 0.4A (and in a preferred embodiment is from 0.05 to 0.4A, e.g. in the range of 0.1A to 0.38A). When the front wall 7 covers a minor portion of the area A of the nominal plane P the aperture 8 will comprise a major portion which helps in stowing and removing articles.

The central position 7c on the nominal plane P preferably defines a maximum angle therebetween of 0 to 45°. We prefer an angle of 20 to 45° and most preferably an angle of to 40°, e.g. 28 to 38° because this appears to be beneficial in capturing steam.

We find that one or more, and preferably a combination of one or more of these features surprisingly effectively captures steam and allows the steam to condense whilst allowing relatively unhindered access to the steriliser unit SH.

In use, with the cowl 1 located on an open top of a steriliser housing SH, and water held within the steriliser housing being heated to at least 82 °C, steam which is generated within the steriliser housing SH will escape via the open top and will rise into the cowl 1 through the open base portion 2. As the steam rises and contacts the top wall 5 it will condense. The condensed water will eventually turn to drops whereupon it will run down the top walls and side walls 3, 4 or back wall 6 and return to the steriliser housing SH.

Because the front wall 7 extends outwardly of the side walls 3, 4 steam carried towards the aperture 8 will, as it rises, be directed into the cowl 1 and either condense on the top wall 5 or the underside of the front wall 7. In either way it will be at least partially inhibited from substantially leaving the cowl 1.

The presence of the aperture 8 allows access to the base part 2 and hence to the steriliser housing SH. Accordingly, it is possible to place articles in the steriliser housing SH (and remove articles therefrom) from outside of the cowl 1.

In a meat processing plant the cowl 1 can be located on a knife sterilising unit SH. Even though the aperture 8 is open to the environment, the shape of the cowl 1 (and in particular the front wall 7 and aperture 8) ensures that steam generated within the sterilising unit SH will not escape the cowl 1 even though there is no physical barrier inhibiting egress of steam (i.e. there is no lid or other closure). Therefore knives can be located in and removed from the sterilising unit SH without having to open and close a lid and steam does not escape into the wider environment. Also, because of the large size of the aperture 8 it is easy and convenient to stow and remove, even long (e.g. 12 inch) bladed knives in (or from) the sterilising unit SH without risk of damage to the operative or the knife.

Conveniently the cowl 1 is fabricated from metal, preferably a metal which is not susceptible to reaction with hot water or steam, for example stainless steel. Metals are very effective because of their high thermal conductivity which ensures that the exterior surface of the cowl 1 will remain at room temperature which will further encourage condensation of steam on the interior surfaces. We have found that 1.5mm thick stainless steel is an effective material for fabrication of the cowl.

Referring now to Figure 4 there is shown a further cowl 100 according to the invention located on a steriliser housing SH having an open top through which steam generated in the housing SH can egress.

The cowl 100 has an open base 202 a pair of side walls 103, 104 which taper upwardly and away from the open base 102, a top wall 105 a back wall 106 and a front wall 107.

The front wall 107 extends outwardly and away from the uppermost portion 103u, 104u of the side walls 103, 104.

In use, steam generated in the housing SH can exit and rise into the cowl 100. As the steam rises it will cool and condense when it comes into contact with one or more of the walls 103, 104, 105, 106, 107 of the cowl 100. The tapered form of the side walls 103, 104 encourages condensed water to flow under the effect of gravity into the housing SH.

Because the front wall 107 extends outwardly beyond the edges of the side walls 103, 104 at least some of the steam which rises and flows outwardly with respect to the side walls 103, 104 will condense on the front wall 107 or top wall 105.

It will be appreciated that the aperture 108 of the cowl 100 is relatively larger than the aperture 8 of the cowl 1, whilst this is advantageous in some respects (it allows easier access) it is disadvantageous in other respects (it increases the likelihood of steam egress). Accordingly, the decision on what form of cowl is to be used will be based on the specific requirements of use. For knife sterilisers in a meat processing plant we prefer to use a cowl according to the first embodiment.

In a specific embodiment for a steriliser with an open top having a surface area of about 365 cm2 (294 x 124 mm), we have found a cowl 1 of the following dimensions particularly useful: Characteristic Range Specific Dimension Height I mm 520 to 600 560 Distance x/mm 100 to 150 125 Maximum distancey/mm 9Oto 120 105 Anglecx/° 26to35 32 AFW 0.25 to 0.5A 0.4A The cowl 1 made according to the range of dimensions, and most preferably to the specific dimensions, was shown to be excellent at retaining steam generated within a sterilising unit on which the cowl 1 was located. Indeed, the cowl 1 almost entirely eliminated steam egress during a test shift of an operative in a meat processing plant. The operative had two knives, one in use and one in the steriliser and he swapped the two at the end of each task, in accordance with standard operating procedures. The curved shape of the top wall and the seamless join to the side walls 3, 4 encourage water condensed from steam to run back into the steriliser, thereby reducing the number of re-filling operations and hence the amount of energy wasted to re-heat water within the steriliser unit.

Using the cowl 1 of the invention steam was captured by the front wall 7 and was either directed towards the top wall 7 and/or side walls 3, 4, or condensed on the underside of the top wall 7.

For one embodiment of meat processing (or other) plant containing plural sterilisers, we have determined that 35 hot water steriliser units operated 8 hours a day, 5 days a week, 52 weeks a year (La 2080 operating hrs/year) will emit 4500 L of water (as steam) when the water is heated to its required sterilisation temperature and the sterilisers are used in accordance with usual practice. The cowls 1 of the invention were able to capture more than 50% of the steam. In actual fact the cowls 1 were able to capture more than 55, 60, 65, 70, 75, 80, 85, 90% of the emitted steam.

Even at a relatively low capture rate of steam (e.g. 70%), 3150L of water will be captured to run back into the steriliser units. Firstly, the recycled water does not need replacing, secondly the recycled water does not need to be heated as much to return to sterilisation temperature and thirdly the condensed steam does not need to be removed from the plant and does not provide a potential source of contamination.

If considered necessary, an optional drip tray can be provided directly under the top wall 7 and below the aperture 8. The drip tray can be angled upwardly from the base portion to allow captured drips to run into the steriliser. Because the top wall 7 does not protrude very far from the side walls 3, 4 the optional drip tray also need not protrude very far, thereby ensuring that the optional tray does not inhibit access to the steriliser unit SH.

The actual dimensions of the cowl will be selected according to the size and shape of the steriliser.

Although the above description has detailed hot water sterilisers, the cowl could be used with other hot liquids to prevent vapour egress. Indeed, the cowl could be deployed with an open top steam steriliser to reduce steam egress.

Claims

Claims 1. A steriliser comprising a housing in which an article to be sterilised is locatable and steriliser means to sterilise an article located in the housing, the housing having an open top to allow articles to be stowed in and removed from the housing and through which steam or vapour generated in the steriliser is free to escape the housing, the steriliser having a cowl located over the open top, the cowl having a top wall, side walls and a front and back wall, wherein one of the front, back and side walls comprises an open aperture through which articles are locatable in and removable from the housing and in use steam or vapour escaping from the housing condenses or is able to condense on one or more of the top wall, side walls, back wall and front wall.
2. A steriliser according to Claim 1, wherein the front wall extends outwardly from front edges of the side walls and top walls.
3. A steriliser according to Claim 1 or 2, wherein the front edges of the side walls and top wall together define a plane and the front wall extends outboard of the plane.
4. A steriliser according to Claim 3, wherein the minimum distance between the nominal plane and the back wall is x, and wherein the maximum distance between the front wall and the nominal plane is y and wherein y is from 0.5x to 1.5x.
5. A steriliser according to any preceding Claim, wherein the front wall has a central portion bounded on each side by a peripheral portion, each peripheral portion being connected to a respective side wall.
6. A steriliser according to Claim 5, wherein the maximum angle between the central portion of the front wall and the or a plane defined by the front edges of the side walls is in the range of 0 to 45°, preferably 25 to 40°.
7. A steriliser according to any preceding Claim, wherein the surface area of the or a plane between the front edges of the side walls and top walls has a surface area A.
8. A steriliser according to Claim 7, wherein the front wall when viewed in a direction orthogonal to the plane, covers a minor portion of the surface area A.
9. A steriliser according to Claim 7 018, wherein the front wall has a surface area and wherein AFW «= 0.75A, for example A «= 0.7, 0.6, 0.5, 0.4, 0.3A, thereby to define the aperture.
10. A steriliser according to any preceding Claim, wherein the side walls flare outwardly from the base portion.
11.A steriliser according to any preceding Claim, wherein the top wall is curved, tapered or slanted to thereby encourage condensed water to flow under gravity towards a lowermost portion.
12.A steriliser according to any preceding Claim, whereby the top wall has a central portion and a peripheral portion, and wherein the peripheral portion is located outboard of a nominal plane defined by an edge of the open top.
13.A steriliser according to any preceding Claim, wherein the top wall provides a condensation surface.
14.A steriliser according to Claim 13, wherein the condensation surface is joined to the side walls in a smooth transition, thereby to encourage condensed water to flow towards the open top under the influence of gravity.
15. A steriliser according to any preceding claim, wherein the cowl is shaped to capture, in use, at least 50% of any steam emitted from the housing, and preferably more than 55, 60, 65, 70, 75, 80, 85, 90% of any steam emitted from the housing.
16. A cowl for use with a steriliser, the cowl comprising an open base portion for operative engagement with the open top of a steriliser and through which, in use, steam escaping from the steriliser is able to enter the interior volume of the cowl, the cowl further comprising an opening through which in use, items are depositable in and removable from the steriliser through the open top, the cowl having a condensation surface locatable over the open top of the steriliser, wherein the condensation surface has a surface area greater than that of the open top.
17. A steriliser cowl having an open base portion which is locatable on the open top of a steriliser and through which steam generated in the steriliser can enter the cowl, the cowl having a front wall comprising an aperture through which access to the steriliser through the open top to deposit and remove articles from the steriliser is possible, the cowl being shaped to inhibit egress of steam from the interior volume of the cowl by condensation on inner surfaces thereof.
18. A cowl according to Claim 16 or 17, shaped to capture, in use, at least 50% of any steam emitted from a steriliser.