WO2012104217A2

WO2012104217A2 - Apparatus and method for separating food slices

Info

Publication number: WO2012104217A2
Application number: PCT/EP2012/051347
Authority: WO
Inventors: Barbara Louise WARBURG; Ian Jeffrey NOBLE; Clive Justin Edmonds
Original assignee: Frito-Lay Trading Company Gmbh
Priority date: 2011-01-31
Filing date: 2012-01-27
Publication date: 2012-08-09
Also published as: GB201101617D0; GB2481471A; WO2012104217A3; GB2481471B

Abstract

An apparatus for separating products carried on a conveyor, the apparatus comprising an input conveyor, the input conveyor having an upstream inlet end, a downstream outlet end, and a product conveying surface between the upstream inlet end and downstream outlet end, a kick roller located adjacent to the downstream outlet end of the input conveyor, the kick roller having at least a portion of an outer rotational surface located beneath the conveying surface of the input conveyor at the downstream outlet end thereof, an output conveyor located beneath the kick roller, and at least one air knife located above the kick roller and adapted to blow air downwardly at an upstream inlet side of the kick roller and at a downstream side of the kick roller. There is also disclosed an apparatus for separating products carried on a conveyor, the apparatus comprising a conveyor and a brush device located above the conveyor, the brush device including a plurality of downwardly directed brush elements mutually spaced in a direction along the length of the conveyor and adapted intermittently to brush products in a direction along the length of the conveyor.

Description

APPARATUS AND METHOD FOR SEPARATING FOOD SLICES

This invention relates to an apparatus and method for separating food slices and has particular application in the manufacture of low oil potato chips.

It has been known for many years to produce potato chips from slices of potato which are fried in oil, usually vegetable oil. Typical conventional potato chips have an oil content of about 30 to 35 wt% oil, based on the total weight of the potato chip. Potato chips exhibit specific organoleptic properties, in combination with visual appearance, to the consumer. The consumer desirous of purchasing a potato chip has a clear expectation of these product attributes in the product.

There is a general desire among snack food manufacturers, consumers and regulatory authorities for healthier food products. In the snack food industry, this has led to a desire for lower fat products. However, even though there may be a general consumer awareness of the benefits of eating lower fat versions of, or alternatives to, existing snack food products, the consumer generally requires the product to have desirable attributes such as texture and flavour. Even if a snack food product is produced which has high nutritional attributes, unless it also has the texture and flavour required by the consumer, the product would not successfully provide the consumer with an acceptable product to replace previous, less healthy snack food products. The challenge among snack food manufacturers is to produce nutritional or more healthy foods which provide the consumer with an improved taste and sensation experience, or at the very least do not compromise on taste and sensation as compared to the consumer's expectation for the particular product or class of products purchased.

There are in the market so-called lower oil snack food products, including potato chips and other products. Some of these processes are produced by modified frying processes using different frying temperatures than those conventionally employed, or cooking processes other than frying, such as baking. Some of these products produce snack foods with low oil, even as low as 5wt%, but the snack food product is not regarded by the consumer to be an acceptable alternative to a potato chip, because the product cannot exhibit the organoleptic properties, in combination with the visual appearance, of a potato chip. WO-A-2008/01 1489 and WOA-2009/091674 in the name of Frito-Lay Trading Company GmbH disclose processes for making a healthy snack food. In those processes, a snack food is made so as to have an appearance and taste similar to conventional fried snack products, such as a potato chip. The potato slices are subjected to a sequence of steps which avoids frying of the slices in oil, and the result is a low fat potato chip.

In particular, these specifications disclose the use of microwave cooking of potato slices which have been preconditioned, for example by being treated in oil. Prior to the microwave cooking process, the potato slices are flexible and flaccid, and have a typical thickness of 1 to 2.5 mm. The microwave cooking rapidly, or explosively, dehydrates the potato slices to achieve low moisture content in a drying step which simulates the conventional frying dehydration rate. The rapid microwave dehydration rigidifies the cooked potato slices, so that they have a crispness resembling that of typical fried potato chips. Additional final drying steps may be employed, for example using microwave drying.

It is disclosed that the oil preconditioning step comprises lipophilic preconditioning by placing the slices into a warm oil flume, a batch kettle or a continuous oil dip. During the lipophilic preconditioning step, a final slice temperature of about 60°C to about 99.9°C and a duration of about 30 to 600 seconds may be employed.

Subsequent to the lipophilic preconditioning step an oil removal step is employed. The oil removal step is disclosed as being performed using a variety of different wet methods, which may, for example, use at least one of the following: a steam blancher; a perforated rotating drum; washing in a hot or cold water bath; pressurised water jets; water knives; air knives; air atomised water nozzles; a mist of fine droplets of water; superheated steam or nitrogen; or centrifugal oil removal. It is disclosed that the most preferred embodiment uses a water spray comprising a mist of fine droplets of water.

After the oil removal step, the outer surfaces, in particular the major surfaces, of the potato slices are still somewhat covered by a layer of oil. It is disclosed that the microwave drying may comprise linear belt or rotary microwave drying. One particular problem with linear belt microwave drying is that the resultant cooked potato slices resemble are planar and resemble biscuits. These slices do not exhibit the random three-dimensional shapes of potato chips. In order to solve this problem, rotary microwave drying is proposed. However, when using such a rotary microwave apparatus, it is difficult to control the tumbling potato slices so that they do not overlap and inadvertently fuse together, cause arcing or ignite during the rapid dehydration process. The oil coating on the slices as they enter either the flat bed or rotary microwave apparatus tends to enhance the stickiness of the potato slices, thereby increasing the proportion of slices which tend to overlap or clump together.

There is therefore a need to reduce the incidence of overlapping or clumping together of potato slices prior to the rotary microwave treatment which explosively dehydrates the potato slices.

Furthermore, after the potato slices exit the microwave treatment, they are subjected to a final drying step in order to reduce the moisture content to a value, typically 1 to 3 wt% water based on the total weight of the potato chips prior to final seasoning, which is conventionally used for potato chips to give the desired crispiness and organoleptic properties expected by the consumer. It is necessary to ensure that the product flow from the rotary microwave apparatus is substantially uniform and that the potato slices form a substantially even product distribution on a conveyer for the final drying treatment so that the drying is substantially uniform throughout the product flow through the drying apparatus.

It is also desired that if the final drying of the potato chips is carried out by a microwave apparatus, the product flow entering the microwave apparatus has a minimum chip overlap, so that fusing or welding together of the potato chips is minimised during the microwave drying process.

There is therefore a need to ensure an even product flow and distribution on a conveyor, optionally with separated products, in particular after a microwave treatment and prior to a drying treatment, which may be a microwave drying treatment, in the manufacture of potato chips from potato slices.

There is accordingly still a need for an apparatus and method for efficiently and reliably manufacturing, in a cost effective manner, a low fat potato chip which has not been fried but has organoleptic properties, in combination with the visual appearance, of a conventional fried potato chip.

Yet further, during various food manufacturing processes it is necessary to change the product density and/or distribution of individual products carried on a conveyor. There is still a need for an apparatus and method which can be used for a variety of food products, particularly delicate food products such as potato chips, which can change the product density and/or distribution of individual products carried on a conveyor.

The present invention accordingly provides an apparatus for separating products carried on a conveyor, the apparatus comprising an input conveyor, the input conveyor having an upstream inlet end, a downstream outlet end, and a product conveying surface between the upstream inlet end and downstream outlet end, a kick roller located adjacent to the downstream outlet end of the input conveyor, the kick roller having at least a portion of an outer rotational surface located beneath the conveying surface of the input conveyor at the downstream outlet end thereof, an output conveyor located beneath the kick roller, and at least one air knife located above the kick roller and adapted to blow air downwardly towards the kick roller.

The present invention further provides a method of separating products carried on a conveyor, the method comprising the steps of:

(a) providing an input flow of products on an upper surface of an input conveyor;

(b) at a downstream end of the input conveyor, engaging upper surfaces of the products with a rotating surface of a kick roller located adjacent to the downstream end, the kick roller having a surface speed higher than a product speed on the input conveyor; and

(c) passing the products through a gap between the kick roller and the downstream end of the input conveyor to eject the products downwardly onto an output conveyor. The present inventors have found that the provision of such a kick roller at the end of a conveyor can separate difficult-to-separate products, such as food slices, in particular potato slices, and that the use of one or more air blades can assist product separation and can also define a landing area on an output conveyor. The result is that the slices are separated and the product density on the input and output conveyors can be modified, in combination with product separation.

The present invention further provides an apparatus for separating products carried on a conveyor, the apparatus comprising a conveyor and a brush device located above the conveyor, the brush device including a plurality of downwardly directed brush elements mutually spaced in a direction along the length of the conveyor and adapted intermittently to brush products in a direction along the length of the conveyor.

(b) providing a brush device located above the conveyor, the brush device including a plurality of downwardly directed brush elements mutually spaced in a direction along the length of the conveyor; and

(c) intermittently brushing products with the brush device in a direction along the length of the conveyor to separate products on the conveyor.

The present inventors have found that the provision of such a brush above a conveyor to cause an intermittent brushing action on the products on the conveyor can separate difficult-to-separate products, such as food products, in particular potato chips, without causing damage to such delicate products.

Preferred features are defined in the dependent claims.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic side view of an apparatus for separating potato slices, prior to microwave cooking, according to a first embodiment of the present invention; and Figure 2 is a schematic side view of an apparatus for separating potato chips, after microwave cooking and prior to a drying step, according to a second embodiment of the present invention

An embodiment of an apparatus for separating potato slices, prior to microwave cooking of the potato slices to form potato chips, according to one aspect of the present invention is illustrated in Figure 1.

An apparatus, designated generally as 2, for separating products carried on a conveyor comprises an input conveyor 4. The input conveyor 4 has an upstream inlet end 6, a downstream outlet end 8, and a product conveying surface 10 between the upstream inlet end 6 and downstream outlet end 8. Preferably, as shown, the input conveyor 4 comprises an endless belt conveyor, comprising a belt 12 with an upper conveying surface 10 mounted on two opposed rollers 14, 16 at least one of which is driven. The input conveyor 4, and also the other belt conveyors described in the illustrated embodiment, is typically permeable to oil and water, and comprises an open mesh structure, for example a stainless steel balanced spiral wire mesh belt.

The input conveyor 4 is inclined upwardly from the upstream end 6 to the downstream end 8 at an angle of up to 10° to the horizontal, optionally from 1 to 5°. A first drive system 18 is provided for driving the input conveyor 4. The first drive system 18 is adapted to drive the conveying surface 10 of the input conveyor 4 at a surface speed of from 0.01 to 0.75 metres per second, optionally from 0.1 to 0.5 metres per second.

A kick roller 20 is located adjacent to the downstream outlet end 8 of the input conveyor 4. The kick roller 20 has an outer rotational surface 22 located beneath the conveying surface 10 of the input conveyor 4 at the downstream outlet end 8 thereof. A kick roller drive system 23 is provided for rotatably driving the kick roller 20. The kick roller 20 is driven in a rotational direction opposite to that of the input conveyor 4. The kick roller drive system 23 is adapted to drive the outer rotational surface of the kick roller 20 at a surface speed of from 2 to 6 metres per second, optionally from 4 to 5 metres per second. A typical surface speed for the kick roller 20 is 4.6 metres per second.

Accordingly, the surface speed of the kick roller 20 is higher than the surface speed of the input conveyor 4, and is typically at least 6 times, more typically at least 10 times, optionally at least 20 times, higher than the surface speed of the input conveyor 4. For example, the ratio of the surface speed of the kick roller to the surface speed of the input conveyor may range from 6: 1 to 30: 1, optionally 10: 1 to 20: 1.

The kick roller 20 is horizontally spaced from the downstream outlet end 8 of the input conveyor 4. The outer rotational surface 22 is located so as to engage an upper surface of products 24 which are outputted from the conveying surface 10 of the input conveyor 4 at the downstream outlet end 8 thereof. The products 24 are urged through a gap 28 between the kick roller 20 and the downstream outlet end 8 of the input conveyor 4. The gap 28 between the outer rotational surface 22 and the downstream outlet end 8 of the input conveyor 4 is from 0.5 to 5mm wide, optionally about 1mm wide. Typically, the outer rotational surface 22 of the kick roller 20 is a knurled metal surface to provide a high friction surface which engages the upper surface 26 of the food products 24 fed from the input conveyor 4, yet which can readily be cleaned.

An output conveyor 30 is located beneath the kick roller 20. Typically, the output conveyor 30 is located a distance of from 50 to 500 mm, optionally from 100 to 300 mm, further optionally about 200 to 250 mm, for example 225 mm, beneath the kick roller 20. Preferably, as shown, the output conveyor 30 comprises an endless belt conveyor 30 comprising a belt 32 with an upper conveying surface 34 mounted on two opposed rollers 36, 38 at least one of which is driven by a drive system 39. The output conveyor 30 is inclined upwardly from an upstream end 40 to a downstream end 42 at an angle of up to 20^° to the horizontal, optionally from 1 to 10° to the horizontal.

The drive system 39 is adapted to drive the conveying surface 34 of the output conveyor 30 at a surface speed of from 0.01 to 1 metres per second, optionally from 0.1 to 0.5 metres per second, further optionally from 0.15 to 0.35 metres per second. Accordingly, the surface speed of the output conveyor 30 is higher than the surface speed of the input conveyor 4. Typically, the ratio of the surface speed of the output conveyor 30 to the surface speed of the input conveyor 4 may range from 1.33 : 1 to 4: 1, optionally about 2: 1.

At least one air knife 50, 52 is located above the kick roller 20. The at least one air knife 50, 52 is adapted to blow air downwardly at an upstream inlet side 54 of the kick roller 20 and at a downstream side 56 of the kick roller 20. In the illustrated embodiment, the at least one air knife comprises a first air knife 50 adapted to direct a first air blade 58 downwardly between the kick roller 20 and the input conveyor 4 and a second air knife 52 adapted to direct a second air blade 60 downwardly at the downstream side 56 of the kick roller 20.

Typically, the first air knife 50 is orientated at an angle of from 0° to 20° to the vertical, optionally about 8^° to the vertical. The first air knife 50 is adapted to urge product 24 into the gap 28. Typically, the second air knife 52 is orientated at an angle of from 0° to 30^° to the vertical, optionally 10° to 30° to the vertical, further optionally about 15° to the vertical. The second air knife 52 blows air downwardly to prevent products 24 exiting between the kick roller 20 and the input conveyor 4 from being expelled forwardly of the second air blade 60 so as to define the forward extent of a landing area 74 on the output conveyor 30.

Typically, at least one of the kick roller 20 and the input conveyor 4 is adjustably mounted so that the vertical position of the kick roller 20 relative to the downstream end 8 of the input conveyor 4 can be varied. In addition, typically the at least one air knife 50, 52 is adjustably mounted so that the angle of the air blown downwardly therefrom can be varied.

An in-feed belt conveyor 62 feeds products 24 into the separating apparatus 2. Typically the products are food products, most particularly food slices. The separating apparatus 2 has particular utility for separating potato slices 24 which are flexible and are wet and coated with surface oil, having been lipophilically preconditioned and subjected to a de- oiling step as described hereinabove. The oil typically comprises a vegetable oil such as sunflower oil, conventionally used for manufacturing potato chips. The oil is employed in the lipophilic preconditioning to provide the required organoleptic properties to the resultant potato chip, which has been cooked by the combination of the preliminary oil treating step and the subsequent microwave explosive dehydration step, and has not been fried, as for a conventional potato chip. Such potato slices are rather sticky, and the slices stick to each other and also tend to adhere readily to the processing apparatus. The slices have a rather random slice distribution both along and across the in-feed belt conveyor 62. In particular, the slices may be wholly or partially overlapping and may be at least partially formed as clumps. The potato slices 24 typically have a thickness of 1 to 2.5 mm, more typically about 1.3 mm (51 thousandths of an inch).

The slices 24 are fed onto the input conveyor 4 from the feed belt conveyor 62. As the slices 24 reach the downstream end 8, the upper surface 26 of any slice 24 carried on the conveying surface 10 is engaged by the high friction outer rotational surface 22 of the kick roller 20. The kick roller 20 is rotating in a rotational direction opposite to that of the input conveyor 4 and at a much higher surface speed than the translational surface speed of the slices 24 on the input conveyor 4. Consequently, the kick roller 20 rapidly exerts a high frictional pulling force on the slice 24. If the slice 24 is a leading slice of a stack 72 of slices 24, the high frictional pulling force on the slice 24 pulls that slice 24 out of the stack 72 and separates the slices 24 of the stack 72. The slices are pulled through the gap 28.

The first air Icnife 50 blows an air blade 58 downwardly onto the slices 24 immediately prior to the slices engaging the kick roller 20. The air knife 50 blows the upper surface 26 of the leading edge of the slice 24 into contact with kick roller 20 and the bottom surface 70 remains in contact with the conveying surface 10 until the slice 24 has been pulled forwardly of the conveying surface 10 by the kick roller 20. The second air knife 52 directs the second air blade 60 downwardly to guide the slices 24 onto the landing area 74 on the output conveyor 30. The second air blade 60 blows the slices 24 coming off the kick roller 20 downwardly onto the output conveyor 30. In addition, the angle of the second air blade 60 relative to the vertical determines the point of impact of the second air blade 60 on the output conveyor 30, which in turn defines the length of the landing area 74. Thereafter, the slices travel on the output conveyor 30 and are then deposited onto an out- feed belt conveyor 76. The out-feed belt conveyor 76 feeds the slices 24 to a subsequent production process, for example microwave explosive dehydration as described herein. The angle of the out-feed belt conveyor 76 is selected, together with the degree of friction of the upper surface, to avoid inadvertent sliding of the slices on the out-feed belt conveyor 76.

The separating apparatus 2 of the present invention can, in particular, separate such potato slices so as significantly to reduce the incidence of slice overlaps. For example, clumps of two or three vertically stacked and overlapping slices, with a high degree of overlap of, for example, 50 to 100% of the slice dimensions on its major surfaces, may be separated into single slices, without about 95% of the slices being single slices, and the remaining slices being double slices, comprising two slices with less than 30% degree of overlap.

When such slice separation is achieved, the separated potato slices may be fed to a microwave apparatus for explosive dehydration of the potato slices, as discussed earlier herein, with a significantly reduced risk of the slices inadvertently fusing/welding together, causing arcing or igniting during the rapid dehydration process in the microwave.

The separator apparatus 2 can separate even stacked potato slices and can also change the product density between the input side and the output side of the separator apparatus 2. On the output side, a steady flow of separated slices can be achieved, which not only has increased slice separation but also can have increased product density, as compared to the input side.

Although the separator apparatus 2 has particular application for separating potato slices, which may be conventionally cut and washed, and may additionally have been pretreated with oil, the apparatus may be used in other food processing systems where there is a need to separate products and/or to change the product density on a conveyor line.

Various parameters can readily be varied by those skilled in the art to achieve the desired separation and final product density depending upon the type and properties of the products to be separated and the product flow rate. For example, the friction characteristics of the conveyors and the kick roller, the dimension of the gap spacing the kick roller from the input conveyor, and the vertical position of the kick roller relative to the downstream end of the input conveyor may be varied using reasonable trial and error to achieve the desired separation for the specified products.

In addition, the rotational speed of the kick roller may be sufficient to ensure self cleaning of the rotational surface of the kick roller by centrifugal action on residue deposited on the rotational surface, such as oil, potato starch, etc..

Preferably, the kick roller speed is selected so as to be sufficient to provide self-cleaning but not substantially greater as higher a kick roller speed relative to the input and output conveyor speeds tends to increase overlap of products on the landing area.

Preferably, the higher is the ratio of the input conveyor speed to the output conveyor speed, the lower the degree of overlap of products on the landing area.

The separator apparatus is readily able to separate the products, such as potato slices, even when they are rather sticky and at least partially stacked. This may be achieved, for stacked products such as potato slices where the leading edge of a top product of a stack is separated from the bottom product of the stack, by providing that both (a) the coefficient of friction between the conveying surface of the input conveyor and the lower surface, contacting the conveying surface, of the bottom product of a stack and (b) the coefficient of friction between the rotational surface of the kick roller and the lower surface of the top product of a stack are greater than (c) the coefficient of friction between the adjacent contacting surfaces of the bottom and top products of the stack.

The gap size between the kick roller and the input conveyor is selected so as to ensure that the specified product passes through the gap with good surface contact between the upper and lower surfaces of the product on the input conveyor and the opposed, oppositely rotating surfaces of the kick roller and the input conveyor respectively. If the gap size is too wide for the product thickness then poor surface contact would reduce separation effectiveness. If the gap size is too narrow for the product thickness then the product may be damaged as it is squeezed between the gap. The kick roller may be located at a vertical position within a vertical range relative to the downstream end of the input conveyor. The kick roller may be at a higher position, which increases the size of the landing area, or a lower position, which decreases the size of the landing area and also progressively makes it more difficult to ensure that the products enter the gap, A typical position achieving reliable separation into an acceptably-sized landing area is for the kick roller to be horizontally opposite the rotating end of the downstream end of the input conveyor, i.e. at a "3 o'clock" position with the axis of the kick roller and the axis of the end roller of the input belt conveyor being substantially horizontal.

The input conveyor may be modified to provide a variable friction belt by application of a variable vacuum to the conveying surface of the input conveyor. The kick roller may correspondingly be modified to provide variable friction rotational surface by application of a variable vacuum to the surface. For each surface, variation of the vacuum would modify the force holding the product against the respective surface. This vacuum facility could be used during production to make continual changes to the frictional surfaces, for example to accommodate variations in temperature and slice stickiness, and hence modify separation performance without stopping the production line.

Examples

The various aspects of the present invention will now be described in greater detail with reference to the following non-limiting Examples.

Examples 1 to 3

In these Examples, a separating apparatus having the structure shown in Figure 1 was used to separate oil-coated potato slices carried on the input conveyor. The input conveyor had a speed of 0.1 metres/second, the output conveyor had a speed of 0.2 metres/second and the kick roller had a speed of 4.6 metres/second. The kick roller was at the 3 o'clock position relative to the downstream end of the input conveyor. The feed rate was 500 grams/minute of potato slices having a thickness of about 1.3 mm. In Example 1 the slice input had 28% of the input slices being single, non-overlapped slices, 22.4% of the input slices being overlapped slices with an overlap of 50% and 49.6% of the input slices being overlapped slices with an overlap of 100%.

In Example 2 the slice input had 0% of the input slices being single, non-overlapped slices, 31.1% of the input slices being overlapped slices with an overlap of 50% and 68.9%o of the input slices being overlapped slices with an overlap of 100%.

In Example 3 the slice input had 100% of the input slices being single, non-overlapped slices, and no slices were overlapped slices.

For each Example, a number of runs were made to determine the slice distribution on the output conveyor.

The results are shown in Table 1.

It may be seen that independent of the three slice input populations the slice distribution on the output conveyor consistently achieved an output having at least about 95% of the slices present as single slices or as double slices with less than 30% overlap. The separating apparatus effectively separated overlapped slices to achieve a lower overlap ratio in the output of the separating apparatus as compared to the input.

In accordance with a further aspect of the invention, another separating apparatus in accordance with an embodiment of the present invention is illustrated in Figure 2. The apparatus of Figure 2 is particularly adapted for separating cooked potato chips prior to microwave drying of the potato chips. As discussed above, potato slices may be subjected to a non-frying manufacturing process in which the potato slices are explosively dehydrated in a microwave to form potato chips. These resulting potato chips have rigidity and crispness, but require a final drying step to reduce their moisture content down to the conventional level for fried potato chips of from 1 to 3 wt% water based on the total weight of the potato chips prior to final seasoning. In order to achieve the desired explosive dehydration but minimise the possibility of fused or welded clumps of potato chips being formed, which is not desirable to the consumer, the high microwave power microwave explosive dehydration step is carried out so as to achieve sufficient explosive dehydration and starch conversion to provide the desired rigid shapes. However, the high microwave power explosive dehydration step is terminated at a relatively high moisture content, typically from 6 to 40 wt%, more typically from 10 to 20 wt%, compared to the final desired moisture content of from 2 to 3 wt% in the final potato chip, so that fusing and welding of the potato chips is minimised.

The potato chips outputting a rotary microwave tend to have random organic shapes, as for conventional fried potato chips, and may be physically interlocked. Furthermore, a proportion of the potato chips outputting the rotary microwave tend to have be welded or fused together. When it is desired to use a flat bed microwave drying process for achieving the final drying step, it is important to ensure that the potato chips to be fed from the rotary microwave and into the flat bed microwave are physically separated so as to minimise the incidence of further potato chip fusion or welding during the flat bed microwave drying process.

Even if the potato chips have been subjected to a high microwave power explosive dehydration step using a flat bed microwave, they still require physical contact to ensure that the potato chips are in the correct state of separation for any downstream drying step.

This embodiment of a separating apparatus is particularly intended for use in separating potato chips prior to final drying, in particular final drying by a flat bed microwave drying process. However, the apparatus and corresponding separating method may additionally have application in other food processing apparatus and methods in which product or slice separation is advantageous or required. Accordingly, an apparatus, designated generally as 102, for separating products comprises a conveyor 104 on which the products are conveyed. The conveyor 104 has an upstream inlet end 106, a downstream outlet end 108, and a product conveying surface 1 10 between the upstream inlet end 106 and downstream outlet end 108. Preferably, as shown, the conveyor 104 comprises an endless belt conveyor, comprising a belt 1 12 with an upper conveying surface 110 mounted on two opposed rollers 1 14, 1 16 at least one of which is driven. The conveyor 104 is typically permeable to oil and water, and may comprise an open mesh structure, for example a stainless steel balanced spiral wire mesh belt, or a continuous polymer belt, optionally with elastomer stiffeners.

The conveyor 104 is substantially horizontally oriented but alternatively may be inclined upwardly or downwardly from the upstream end 106 to the downstream end 108 at an angle of up to 10^° to the horizontal, optionally up to 5°, such as from 1 to 5°. A first drive system 1 18 is provided for driving the conveyor 104. The first drive system 1 18 is adapted to drive the conveying surface 1 10 of the conveyor 104 in a forward direction at a surface speed of from 0.01 to 0.5 metres per second, optionally from 0.05 to 0.15 metres per second, further optionally about 0.1 metres per second.

The upper conveying surface 1 10 is provided with a series of transversely oriented separating strips 210. The separating strips 210 form a continuous series of indexed regions 212 along the length of the upper conveying surface 1 10. The separating strips 210 are mutually separated by a selected pitch PI and have a selected height and thickness, all these parameters being selected based on the nature, size and configuration of the products to be separated. The pitch is typically from 40 to 100 mm, more typically from 50 to 80 mm, for example 67 mm when the products are potato chips. The height is typically from 2 to 10 mm, more typically from 3 to 7 mm, for example 3.5 mm when the products are potato chips. The width is typically from 1 to 10 mm, more typically from 2 to 8 mm, for example 4 mm when the products are potato chips. The strip may have a square, rectangular or trapezium cross-section, in the latter case typically having a lower width of about 8 mm and an upper width of about 3 mm.

The products are fed onto the upstream end 106 of the conveyor 104 as a substantially continuous flow and at a product density, dependent upon the speed of the conveyor 104, to be able to provide a substantially uniform product density of separated, non-overlapped products. The input product flow however tends to be not completely uniform, either along the length or across the width of the conveyor 104, but rather has some regions of stacked or physically overlapping or interlocked products.

An upper brush device 220 is provided above the conveyor 104 physically to brush the products as they are conveyed by the conveyor 104 so as at least partially to remove these regions of stacked or physically overlapping or interlocked products.

The brush device comprises an endless belt 222 mounted between rollers 224, 226. The endless belt includes a lower portion 228 which is vertically spaced from the conveying surface 1 10 of the conveyor 104. The lower portion 228 and the conveying surface 1 10 may be mutually parallel or mutually inclined.

A second drive system 230 is coupled to one of the rollers 226 and is adapted selectively to rotate the endless belt 22 in a forward direction F or a reverse direction R. In the forward direction, the lower portion 228 and the conveying surface 110 travel in the same direction. The second drive system 230 is adapted to drive the endless belt 222 at a surface speed of from 0.01 to 0.5 metres per second, optionally from 0.05 to 0.15 metres per second, further optionally about 0.1 metres per second.

The first and second drive systems 1 18, 230 are independently controllable so that the relative speed of the conveyor 104 and the endless belt 22 can be controlled.

The outer surface 232 of the endless belt 222 is provided with a series of transversely oriented flexible brush elements 234 which extend substantially perpendicularly to the outer surface 232. However, in an alternative embodiment the brush elements 234 may be inclined at an acute angle to a virtual line perpendicular to the outer surface 232 The filaments of the brush elements 234 may be composed of a polymer such as polypropylene or a flexible elastomer. The material may be selected to provide a desired flexibility of the brush elements dependent upon the desired drag to be applied to the products in order to separate them. The brush elements 234 are spaced along the length of outer surface 232 of the endless belt 222. The bmsh elements 234 are mutually separated by a selected pitch P2 and have a selected length L and thickness, all these parameters being selected based on the nature, size and configuration of the products to be separated. The pitch is typically from 50 to 100 mm, more typically from 60 to 90 mm, for example 86 mm (centre to centre) when the products are potato chips. The pitch P2 is typically different from the pitch PI, and optionally is higher than the pitch PI , but they may be similar. The brush length is typically from 50 to 150 mm, more typically from 90 to 130 mm, for example 120 mm when the products are potato chips. The brush elements 234 are transversely linear and typically have a width of from 1 to 20 mm, more typically from 5 to 15 mm, for example 9 to 12 mm when the products are potato chips.

The brush elements 234 may be perpendicular (i.e. at 90 degrees) to the outer surface 232 of the endless belt 222 or alternatively may be inclined to the outer surface 232 of the endless belt 222, for example at an angle of from 45 to less than 90 degrees, more typically from 75 to less than 90 degrees, optionally 82 degrees when the products are potato chips.

The height of the endless belt 222 relative to the conveyor 104 can be adjusted by a height adjusting device 236, which in turn can vary the spacing between the lower ends 238 of the brush elements 234 and the upper conveying surface 1 10 of the conveyor 104. Typically, the lower ends 238 of the brush elements 234 are spaced a distance D of from 5 to 75 mm above the upper conveying surface 1 10.

In use, the products to be separated, such as potato chips, are fed from an in-feed conveyor 240 onto the upper conveying surface 110 at the upstream end 106. The layer of products is deposited substantially across the conveyor width as a layer which extends along the length direction of the upper conveying surface 1 10. The products can bridge the separating strips 210. The products proceed forwardly on the conveyor 104, and then are brushed by the moving brush elements 234.

The brush elements 234 provide a repeated reverse drag force or forward pushing force, depending upon the direction of rotation of the endless belt 222, using an intermittent sweeping motion of the indexed brush elements 234 against the upper surface of the layer of products.

The brush elements 234 are typically driven in a forward direction, so that the brush elements 234 are moving in the same direction to the products on the conveyor 104, but optionally at a higher translational speed than the products, which has been found to enhance product separation. However, the brush elements 234 may be driven in a reverse direction, for example in order to even out the product flow and remove a back log of products on the conveyor 104.

The brush elements 234 repeatedly apply a low separating force, along the length direction of the moving layer, which acts to separate the products longitudinally as the brush filaments translate and flex against the products. The strength of the force for any given layer of products can be varied by modifying the height of the spacing between the lower ends of the brush elements 234 and the upper conveying surface 1 10.

The upper conveying surface 1 10 is of a high friction material to provide frictional engagement with the lower surface of the products. The brush filaments, which can flex under the brushing action, tend to provide a frictional engagement with the products which is (a) lower than the frictional engagement between the products and the conveying surface 110 so products are not brushed off the surface, but (b) higher than the frictional engagement between products so products are separated. This contributes to product separation without causing product damage.

The separating strips 210 act to enhance the friction between the products and the conveying surface 110. The separating strips 210 act to prevent the entire layer being brushed longitudinally along the endless belt 222, and act to hold the lowermost products in the layer on an indexed portion of the conveyor 104, defined between adjacent separating strips 210, to allow the uppermost products of the layer to be brushed away from the lowermost products.

The different pitches P2, PI between on the one hand the brush elements 234 and on the other hand the separating strips 210 ensures that the brushing action has a more random effect on separating the products than if the movement of the brush elements 234 and the separating strips 210 was more synchronised by having a common pitch.

Although the illustrated embodiment has been particularly described with reference to the separation of potato chips, the apparatus and method have utility in the separation of other products, particularly food products such as pieces or chips of fruit or vegetable, or corn chips, to provide an even uniform flow of separated products for a subsequent processing operation.

The repeated brushing action enhances product separation without product damage. This is particularly important when the products are potato chips. The brushing action can separate partially fused chips and physically interlocked chips. The intermittent longitudinal separation force tends not to damage the products, for example does not create broken chips, and creates an even layer of separated products for subsequent processing, for example a microwave drying process for potato chips. The potato chips can be separated without being crushed. This process can particularly be employed to separate the potato chips when the moisture content of the potato chips is from 6 to 40 wt% based on the total weight of the potato chips prior to seasoning. Within such a range of moisture content, the chips can have sufficient rigidity to be separable by the brushing action but are not so brittle that they would be liable to excessive breakage.

The flexible brush filaments accommodate different degrees of clumping of the products on the conveyor 104. Differently sized clumps can reliably be separated by the brushing action without damaging the products. The repeated intermittent brushing action enhances product separation without causing inadvertent product damage.

In an alternative embodiment, the brush elements are static, and the repeated intermittent brushing action is achieved by translating the products on the conveyor 104 under the series of brush elements.

Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art.

Claims

CLAIMS:

1. An apparatus for separating products earned on a conveyor, the apparatus comprising an input conveyor, the input conveyor having an upstream inlet end, a downstream outlet end, and a product conveying surface between the upstream inlet end and downstream outlet end, a kick roller located adjacent to the downstream outlet end of the input conveyor, the kick roller having at least a portion of an outer rotational surface located beneath the conveying surface of the input conveyor at the downstream outlet end thereof, an output conveyor located beneath the kick roller, and at least one air knife located above the kick roller and adapted to blow air downwardly towards the kick roller.

2. An apparatus according to claim 1 , wherein the at least one air knife comprises a first air knife adapted to direct a first air blade downwardly between the kick roller and the input conveyor and a second air knife adapted to direct a second air blade downwardly at a downstream side of the kick roller.

3. An apparatus according to claim 2, wherein the first air knife is orientated at an angle of from 0^° to 20^° to the vertical, optionally about 8^° to the vertical.

4. An apparatus according to claim 2 or claim 3, wherein the second air knife is orientated at an angle of from 10° to 30° to the vertical, optionally about 15^° to the vertical.

5. An apparatus according to any foregoing claim, wherein the kick roller is laterally spaced from the downstream outlet end of the input conveyor and the outer rotational surface is located so as to engage an upper surface of products output from the conveying surface of the input conveyor at the downstream outlet end thereof, the products being urged through a gap between the kick roller and the downstream outlet end of the input conveyor.

6. An apparatus according to any foregoing claim, wherein the gap between the outer rotational surface and the downstream outlet end of the input conveyor is from 0.5 to 5mm wide, optionally about 1mm wide.

7. An apparatus according to any foregoing claim, wherein the outer rotational surface of the kick roller is a knurled metal surface.

8. An apparatus according to any foregoing claim, further comprising a first drive system for driving the input conveyor, the first drive system being adapted to drive the conveying surface of the input conveyor at a first surface speed, and a kick roller drive system for rotatably driving the kick roller, the kick roller system being adapted to drive the outer rotational surface of the kick roller at a second surface speed, wherein the second surface speed is higher than the first surface speed.

9. An apparatus according to claim 8, wherein the second surface speed is from 2 to 6 metres per second, optionally from 4 to 5 metres per second and/or wherein the first surface speed is from 0.01 to 0.75 metres per second, optionally from 0.1 to 0.5 metres per second.

10. An apparatus according to claim 8 or claim 9, wherein the ratio of the second surface speed to the first surface speed ranges from 6:1 to 30:1, optionally 10:1 to 20: 1.

1 1. An apparatus according to any one of claims 8 to 10, further comprising a second drive system for driving the output conveyor, the second drive system being adapted to drive a conveying surface of the output conveyor at a third surface speed, wherein the second surface speed is higher than the third surface speed.

12. An apparatus according to claim 1 1, wherein the third surface speed is from 0.01 to 1 metres per second, optionally from 0.1 to 0.5 metres per second, further optionally from 0.15 to 0.35 metres per second, and/or wherein the ratio of the third surface speed to the first surface speed is from 1.33: 1 to 4: 1, optionally about 2: 1.

13. An apparatus according to any foregoing claim, wherein the input conveyor is inclined upwardly from the upstream end to the downstream end at an angle of up to 10° to the horizontal, optionally from 1 to 5°.

14. An apparatus according to any foregoing claim, wherein at least one of the input conveyor and the output conveyor comprises an endless belt conveyor.

15. An apparatus according to any foregoing claim, wherein the output conveyor is inclined upwardly from an upstream end to a downstream end at an angle of up to 20^° to the horizontal, optionally from 1 to 10^°.

16. An apparatus according to any foregoing claim, wherein the output conveyor is located a distance of from 50 to 500 mm, optionally from 100 to 300 mm, further optionally about 200 mm beneath the kick roller.

17. An apparatus according to any foregoing claim, wherein at least one of the kick roller and the input conveyor is adjustably mounted so that the vertical position of the kick roller relative to the downstream end of the input conveyor can be varied.

18. An apparatus according to any foregoing claim, wherein the at least one air knife is adjustably mounted so that the angle of the air blown downwardly therefrom can be varied.

19. An apparatus according to any foregoing claim, wherein the apparatus for separating products is located between, on an upstream side thereof, a de-oiling station downstream of a oil pre-conditioning station, and on a downstream side thereof, a microwave cooking apparatus, in an apparatus for manufacturing potato chips from potato slices.

20. A method of separating products carried on a conveyor, the method comprising the steps of:

(c) passing the products through a gap between the kick roller and the downstream end of the input conveyor to eject the products downwardly onto an output conveyor.

21. A method according to claim 20, further comprising the step of directing a first air blade towards the kick roller to urge products through the gap between the kick roller and the downstream end of the input conveyor.

22. A method according to claim 21, wherein the first air blade is orientated at an angle of from 0^° to 20^° to the vertical, optionally about 8^° to the vertical.

23. A method according to any one of claims 20 to 22, further comprising the step of directing a second air blade towards a downstream side of the kick roller to define a downstream extremity of a landing area on the output conveyor.

24. A method according to claim 23, wherein the second air knife is orientated at an angle of from 10° to 30° to the vertical, optionally about 15^° to the vertical.

25. A method according to any one of claims 20 to 24, wherein the gap is from 0.5 to 5 mm wide, optionally about 1 mm wide.

26. A method according to any one of claims 20 to 25, wherein the rotating surface of the kick roller is a knurled metal surface.

27. A method according to any one of claims 20 to 26, wherein the surface speed of the kick roller is from 2 to 6 metres per second, optionally from 4 to 5 metres per second and/or the speed of products on the input conveyor is from 0.01 to 0.75 metres per second, optionally from 0.1 to 0.5 metres per second.

28. A method according to any one of claims 20 to 27, wherein the ratio of the surface speed of the kick roller to the speed of products on the input conveyor ranges from 6: 1 to 30: 1, optionally 10:1 to 20: 1.

29. A method according to any one of claims 20 to 28, wherein the speed of products on the output conveyor is from 0.01 to 1 metres per second, optionally from 0.1 to 0.5 metres per second, further optionally from 0.15 to 0.35 metres per second, and/or wherein the ratio of the third surface speed to the first surface speed is from 1.33: 1 to 4: 1 , optionally about 2: 1.

30. A method according to any one of claims 20 to 29, wherein the input conveyor is inclined upwardly from an upstream end to the downstream end at an angle of up to 10^° to the horizontal, optionally from 1 to 5^°.

31. A method according to any one of claims 20 to 30, wherein the output conveyor is inclined upwardly from an upstream end to a downstream end at an angle of up to 20^° to the horizontal, optionally from 1 to 10°.

32. A method according to any one of claims 20 to 31 , wherein the output conveyor is located a distance of from 50 to 500 mm, optionally from 100 to 300 mm, further optionally about 200 mm beneath the kick roller.

33. A method according to any one of claims 20 to 32, wherein the products comprise potato slices, optionally coated in oil.

34. A method according to claim 33, wherein the potato slices on the input conveyor are received from a de-oiling station downstream of an oil pre-conditioning station and the potato slices on the output conveyor are conveyed to a microwave cooking apparatus for manufacturing potato chips from the potato slices.

35. An apparatus for separating products carried on a conveyor, the apparatus comprising a conveyor and a brush device located above the conveyor, the brush device including a plurality of downwardly directed brush elements mutually spaced in a direction along the length of the conveyor and adapted intermittently to brush products in a direction along the length of the conveyor.

36. An apparatus according to claim 35, wherein the brush device comprises an endless belt carrying a series of transversely oriented flexible brush elements and a drive system for rotating the endless belt.

37. An apparatus according to claim 36, wherein the drive system for rotating the endless belt is adapted selectively to rotate the belt at a selected speed in a forward or reverse direction.

38. An apparatus according to claim 36 or claim 37, wherein a portion of the endless belt is substantially aligned with a portion of the conveyor located thereunder.

39. An apparatus according to any one of claims 35 to 38, wherein the brush elements are mutually separated by a pitch of from 50 to 100 mm, optionally from 60 to 90 mm, further optionally about 86 mm.

40. An apparatus according to any one of claims 35 to 39, wherein the brush elements include filaments which have a length of from 50 to 150 mm, optionally from 90 to 130 mm, further optionally about 120 mm.

41. An apparatus according to any one of claims 35 to 40, further comprising a height adjusting device for adjusting the height of the brush elements relative to the conveyor.

42. An apparatus according to any one of claims 35 to 41 , wherein lower ends of the brush elements are spaced a distance of from 5 to 75 mm above a conveying surface of the conveyor.

43. An apparatus according to any one of claims 35 to 42, further comprising a series of transversely oriented separating strips on an upper conveying surface of the conveyor to form a continuous series of indexed regions along the length of the upper conveying surface.

44. An apparatus according to claim 43, wherein the separating strips are mutually separated by a pitch of from 40 to 100 mm, optionally from 50 to 80 mm, further optionally about 67 mm.

45. An apparatus according to claim 43 or claim 44, wherein the separating strips have a width of from 1 to 10 mm, optionally from 2 to 8 mm, further optionally about 4 mm.

46. An apparatus according to any bone of claims 43 to 45, wherein the separating strips have a height of from 2 to 10 mm, optionally from 3 to 7 mm, further optionally 3.5 mm.

47. A method of separating products carried on a conveyor, the method comprising the steps of:

(b) providing a brush device located above the conveyor, the brush device including a plurality of downwai'dly directed brush elements mutually spaced in a direction along the length of the conveyor; and

48. A method according to claim 47, wherein the brush device comprises a rotating endless belt carrying a series of transversely oriented flexible brush elements.

49. A method according to claim 48, wherein the endless belt is selectively rotated at a selected speed in a forward or reverse direction.

50. A method according to claim 48 or claim 49, wherein a portion of the endless belt is substantially aligned with a portion of the conveyor located thereunder.

51. A method according to any one of claims 47 to 50, wherein the brush elements are mutually separated by a pitch of from 50 to 100 mm, optionally from 60 to 90 mm, further optionally about 86 mm.

52. A method according to any one of claims 47 to 51, wherein the brush elements include filaments which have a length of from 50 to 150 mm, optionally from 90 to 130 mm, further optionally about 120 mm,

53. A method according to any one of claims 47 to 52, further comprising adjusting the height of the brush elements relative to the conveyor.

54. A method according to any one of claims 47 to 53 wherein lower ends of the brush elements are spaced a distance of from 5 to 75 mm above a conveying surface of the conveyor.

55. A method according to any one of claims 47 to 54, wherein a series of transversely oriented separating strips are provided on an upper conveying surface of the conveyor to form a continuous series of indexed regions along the length of the upper conveying surface.

56. A method according to claim 55, wherein the separating strips are mutually separated by a pitch of from 40 to 100 mm, optionally from 50 to 80 mm, further optionally about 67 mm.

57. A method according to claim 53 or claim 54, wherein the separating strips have a width of from 1 to 10 mm, optionally from 2 to 8 mm, further optionally about 4 mm.

58. A method according to any one of claims 55 to 57, wherein the separating strips have a height of from 2 to 10 mm, optionally from 3 to 7 mm, further optionally 3.5 mm.

59. A method according to any one of claims 47 to 58, wherein the products comprise potato chips,

60. A method according to claim 59, wherein the potato chips on the conveyor are received from a microwave cooking apparatus and conveyed to drying apparatus, optionally a microwave drying apparatus.

61. A method according to claim 59 or claim 60, wherein the potato chips received from the microwave cooking apparatus have a water content of from 6 to 40 wt%, optionally from 10 to 20 wt%, based on the total weight of the potato chip prior to seasoning.