GB2341082A

GB2341082A - Food processing

Info

Publication number: GB2341082A
Application number: GB9819195A
Authority: GB
Inventors: Allan Edward Plant
Original assignee: Spooner Industries Ltd
Current assignee: Spooner Industries Ltd
Priority date: 1998-09-04
Filing date: 1998-09-04
Publication date: 2000-03-08
Anticipated expiration: 2018-09-04
Also published as: GB2341082B; GB9819195D0

Abstract

A conveyor 10 supports a series of disc shaped moulds 12 each having batter contained therein. The moulds are advanced in the direction of arrow 14. The base of the conveyor is subjected to heat from a series of transverse gas burners 16. Two heater units 22 direct high velocity hot air through several outlets (26 fig.2) and on to the upwardly facing surface of the product in the moulds to toast or brown the surface of the product.

Description

2341082 FOOD PROCESSING The present invention relates to food processing

apparatus, a method of processing food and to a food product when produced by a food process. The invention is particularly, although not exclusively, applicable to the toasting or browning of the surface of crumpets and scotch pancakes.

one particular problem associated with the toasting process is that the traditional methods can produce black spots on the surface where there are bubbles just underneath. Hence there is an obvious requirement for a device positioned over the hotplate that will evenly brown is the surface of the product.

The traditional methods of "browning" use either contact heating or infra red heating.

There are problems which can be attributed to the use of contact heating, which usually means lowering a heated plate to make contact with the top of the produce each time that the hotplate is stopped. Some of these problems are: - 1. A mechanism is required to lower the plate which is heated at the back by ribbon gas burners, necessitating a flexible gas pipe; 2. The plate can distort and may not always make even contact with the product; 3. Temperature control of the plate is difficult and usually non-existent; 2 4. Contact with the product can cause charred pieces to adhere to the plate and be transferred to other products; 5. The back of the plate is uninsulated and gives off a great deal of heat as do the flames from the burners. The resultant heat loss means that it is inefficient, and 6. A canopy over the plate collects only some of the exhaust gases from the gas burners.

There are also problems which can be attributed to the use of gas fired infra red. This leads to a hostile environment surrounding the unit due to the very high radiation temperature and consequent heat loss, with attendant inefficiencies.

It is an object of the present invention to attempt to overcome at least some of the above disadvantages.

According to one aspect of the present invention, food processing apparatus comprises hot air supply means and outlet means arranged to direct hot air at the upwardly facing surface of a food product.

The hot air supply means may be arranged to supply air at a velocity of greater than 10 m/s or greater than 20 m/s or in the region of 30 m/s.

The clearance between the outlet means and the food product may be arranged to be less than 60 mm, less than mm, less than 40 mm or less than 30 mm or in the region - of 25 mm.

The hot air supply means may be arranged to supply air at a temperature greater than 100 or greater than 140, or in the region of 1700C, or less than 350 or less than 300 or less than 250 or less than 2000C.

The hot air supply means may be arranged to supply air at greater than atmospheric pressure or greater than 20 or greater than 30 or greater than 40 or in the region of 55 mm water gauge at 200C.

The outlet means may comprise at least one nozzle. A plurality of nozzles may be provided for each product. The area of the outlet of the nozzle or nozzles for each product relative to the upwardly facing surface of that is product may be arranged to be in a ratio greater than 1:4, 1:5 or 1:6 or in the region of 1:7, or less than 1:10, or 1:9 or 1:8.

The apparatus may also include at least one gas burner located beneath the outlet means with the gas burner being arranged to direct a flame upwardly. The outlet means and the gas burner may be arranged to be offset from each other whereby gas exiting the outlet means does not impinge directly on the source of the flame.

The outlet means may include more than one outlet and at least two of the outlets may be arranged to emit air supplied from a different supply region. Each supply region may be arranged to have air supplied from a common source.

The outlet means may be arranged to conform generally to the shape of the upwardly facing surface of the food product to be processed.

The apparatus may include a conveyor arranged to cause movement of a product past the outlet means. The conveyor may be arranged to cause successive products to be moved past the outlet means either in a stepwise 5 fashion or in a continuous movement. The conveyor may be arranged to have a plurality of products extending in a row across a conveyor and those products in that row may be arranged to be spaced from each other. The outlet means may be arranged to direct air at each product in the 10 row but not at locations between the products in the row.

The apparatus may include a plurality of outlet means that are arranged to successively direct air at the same product. Each outlet means may be as herein referred to.

The apparatus may be arranged to have air removed from around the side of the outlet means or from around the complete periphery of the outlet means. That air may be arranged to be removed in an upwards direction. That air may be arranged to be removed by creating a pressure in the region of atmospheric pressure or slightly less than atmospheric pressure.

The apparatus may include means for recycling at least part of the air that has been removed to the outlet means again.

In the present invention where the term 'lair" is used it will be appreciated that any gas, and not just air is covered.

According to another aspect of the present invention a method of processing food comprises directing hot air at the upwardly facing surface of a food product.

The method may comprise directing air at the surface of the food product greater than 10 m/s or greater than 20 m/s or in the region of 30 m/s.

The method may comprise pressurising air in order to direct air at the surface of a food product and that method may comprise pressurising the air at greater than or greater than 30 or greater than 40 mm of water gauge at 200C or in the region of 55 mm of such a gauge.

The method may comprise directing air from a plurality of outlets at the upwardly facing surface of the food product and the method may comprise directing air from outlets that have a ratio of outlet area to product is area, over the extent of the product, of greater than 1:4 or 1:5 or 1:6 or in the region of 1:7 or less than 1:10 or less than 1:9 or within the region of 1:8.

The method may comprise directing air at the food product with the air that is so directed conforming to the shape of the food product. The method may comprise directing air at a spaced row of food products with air being directed at each food product but not, to any substantial extent, in the spaces between the food products.

The method may comprise removing air that has been directed at the surface of the food product, for instance by causing a pressure of less than that of the air that is directed at the food product to take that air away subsequently. The method may comprise removing air from around substantially the complete periphery of the food product. The method may comprise recycling at least some of the air that has been removed to direct it again at the food product.

The method may comprise moving the foodproduct relative to hot air that is able to be directed in order to cause the food product to have different regions of hot air directed at it. Those regions of air may be arranged to be sequentially directed at the food product.

The food product may be arranged to be stationary during at least part of the time that hot air is directed at the food product.

The method may comprise passing the food product through at least two streams of hot air that is directed towards the upwardly facing surface of the food product with at least one of those streams of hot air having at least a partial cooking effect on the product.

The method may comprise browning or toasting the surface of a food product with the downwardly directed hot air. The method may comprise controlling the hot air to vary the amount of browning or toasting of a product, or to maintain the same browning or toasting of the product.

The present invention also includes a food product when produced by a method as herein referred to.

The present invention can be carried into practice in various ways but one embodiment will now be described, by way of example, and with reference to the accompanying drawings in which:

Figure 1 is a schematic perspective view of part of a food processing arrangement incorporating two heater units; Figure 2 is an underneath view of a heater unit; Figure 3 is a side view of the heater unit of Figure 2; Figure 4 is a view on the section X-X of Figure 3, and Figure 5 is a schematic representation of the flow system for the air of a heater unit.

As shown in Figure 1, the food processing arrangement includes a conveyor 10 that supports a series of disc shaped moulds 12. Each mould has had batter poured into the centre of the mould at an upstream location (not shown) so that the batter f lows out from the centre of the is base of the mould to the surrounding cylindrical wall.

As the moulds are advanced in the direction of arrow 14, the base of the conveyor is subjected to heat from a series of transverse gas burners 16. Each burner 16 directs flames from nozzles 18, that may be ribbon nozzles, upwardly to the conveyor. The heat is then conducted through to the moulds to heat those moulds and to gradually assist in cooking the batter as the conveyor advances. However, the batter is cooked more from the heat supplied from the top than this heat source. Each burner 16 is supplied with gas from a common supply pipe 20 running to the side of the conveyor, beneath the conveyor.

Atthe downstream location of the conveyor shown in Figure 1, two heater units 22 are shown in series with each other but spaced slightly apart in the direction of travel. The operation of each heater unit will be described later but the effect of each unit 22 is to direct heat onto the upwardly facing surface of the product in the moulds. Both units have the effect that relatively extreme heat is forced onto the upper surface of the product. The main effect of that heat is to toast or brown the surface of the product. The product though may also be cooked to an extent as a result of the heat being applied.

The moulds are arranged in rows of six (although only five are shown) across the conveyor. In order to fill the moulds at the upstream location the conveyor is advanced in a step-wise fashion with the conveyor being stationary while one or more of the rows are filled and with the conveyor being moved forward after filling. Whilst the conveyor is stationary the product within the heater units is 22 is subject to the greatest intensity of heat being blasted against its upper surface. It is thought that the duration that the conveyor is stationary for will be slightly more than 1.7 sec. with the conveyor being stationary for slightly less than 1 sec. in each step-wise event.

Both heater units 22 are the same. Accordingly one of those units will now be described with. reference to Figures 2 to 4.

In Figure 2, the underneath of each bar 24 can be seen. It is the underneath of the bars that faces downwardly onto the upwardly facing surface of the product.

The bars 24 are arranged with their length perpendicular to the direction of travel indicated by the arrow 14. Each bar includes a cluster of holes 26 which, in use, comprise nozzles through which hot air is directed down on the product. Each cluster is generally of a circular configuration corresponding to the surface area of the product whereby air is directed at substantially the complete top surface of a circular product accurately aligned beneath the cluster but air is not blasted down between adjacent products in the row or from in front of or behind the products. This is efficient as air is only directed at the product to be browned or toasted at least whilst the conveyor is stationary.

The centre of each air bar is spaced apart from the centre of an adjacent air bar by the same distance as the centre of a mould in adjacent rows. Accordingly during the "stop" part of the step- wise advancement of the conveyor, a mould with product will be accurately aligned beneath each cluster.

The burners 16 are arranged centrally beneath each air bar. If the air was blasted directly down from a hole 26 onto a nozzle 18 then the flame from that nozzle, or the series of nozzles may be blown out. Accordingly, no holes 26 are on the centre line 28 of the bars 24 and thus, when the conveyor is advancing and there is a gap between the air bars and the burners, that gap is not such that air from an opening can blow a burner out.

The heater unit 22 is mounted above the conveyor on four legs 30, one at each corner, that extend down to allow the unit to straddle the conveyor.

Hot air is supplied to the burners through an inlet duct 32. This air is divided by a horizontal wall 34.

Half of the air is provided to a forward chamber 36 that is in communication with the holes on the three upstream bars and the remainder is fed to the four downstream air bars through a chamber 38. The air temperature is sensed - by a thermocouple 39 and the temperature of the air can be controlled in dependence upon the desired temperaturee with the sensed temperature.

The chambers 36 and 38 are also in communication with a ledge 40 that surrounds the air bars. The ledge 40 includes a series of openings 42 along its extent through which bolts pass to secure the nozzle sheet to the plenum chamber.

Air is,removed evenly from around the periphery of the ledges 40 by a cavity 44 that completely surrounds the ledge 40 and which extends upwardly to a chamber 46 located on top of the air bar chambers 36 and 38. Reduced is pressure in the region of 100 Pa is induced in the chamber 46 via a suction force or fan drawing air through an outlet 48. That outlet 48 may remove air from the edge of the chamber 46. Alternatively or additionally a conduit 50 may extend into the chamber 46 such that air enters the 20 conduit through an opening 52 that extends, in plan, more towards one side than the other and then towards the other side as the opening approaches a middle region of the chamber.

Although the air bars are closely spaced from each other, there is a small gap between each air bar. A wall 54 prevents air from being blasted from the chambers 36 and 3 8 through that gap The wall also constrains air beneath the chambers to flow along the underside of those walls to the cavity 44 at the sides.

Figure 5 is a schematic representation of the flow system for the air. The air enters the chambers 36 and 38 via the inlet 32, then enters the cavity 44 before leaving 35 through the outlet 48. The air is drawn through the 1 outlet by a fan 56 and then has heat added to it by direct gas firing 58, or indirect gas, oil or electricity. Then a fan 60 drives the gas under pressure to the inlet 32.

The fans and gas firing may be located beneath the 5 conveyor.'Some air may be exhausted from the system.

Although the present invention has been described as operating in a stepwise fashion it would be possible for the conveyor to move continuously. For continuous movement of the conveyor the moulds would probably be filled by a station that moved with the nozzle when filling the moulds.

The air is directed, by forced convection, downwardly is onto the surface of the product. Crumpets, scotch pancakes and farinaceous products are particularly suited to this convection heating as it causes effective, even browning or toasting of the product without any significant presence of black spots on the surface of the product. Furthermore, with products that are intended to rise when being heated, it has been found that the direct impingement of the air causes the product to rise more than in conventional methods. Consequently, for a given rise in product, less material has to be used with the forced convection of the present invention than in the previous methods used.

If the product becomes too brown or toasted, or if the browning or toasting is desired to be reduced, then either the velocity of the air exiting the nozzles could be reduced, for instance by decreasing the drive from the fan 60, or the temperature of the air could be reduced by altering the gas burner or the conveyor at rest duration could be shortened or any combination thereof could be used. Any or all of these parameters could be altered the opposite way if the product was not browned or toasted enough or if the browning or toasting were to be increased.

Air is arranged to leave each opening 26 in the region of 30 m/s.

The clearance of each hole 26 (or the underside of the air bars) f rom the top of the product is in the region of 25 mm.

The heat of the air impinging on the product is in the region of 1700C.

The pressure of the air within the chambers 36 and 38 is in the region of 55 mm of a water gauge at 200C. The pressure in the cavity 44 may be in the region of atmospheric pressure or slightly less.

The diameter of each hole 26 in the air bars is 6 mm.

The diameter of the pancake or crumpet is in the region of mm. Accordingly, the ratio of the area of the 22 holes of each cluster to the area of product experiencing forced convection is 1:7.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or 1 process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment (s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

14

Claims

CLAIMS 1. Food processing apparatus comprising hot air supply means and

outlet means arranged to direct hot air at 5 the upwardly facing surface of the food product.

2. Apparatus as claimed in Claim 1 in which the hot air supply means is arranged to supply air at a velocity greater than 10 m/s.

3. Apparatus as claimed in Claim 2 in which the hot air supply means is arranged to supply air at a velocity of greater than 20 m/s.

4. Apparatus as claimed in Claim 2 or 3 in which the hot air supply means is arranged to supply air at a velocity of greater than 30 m/s.

5. Apparatus as claimed in any preceding claim in which the clearance between the outlet means and the food product is arranged to be less than 60 mm.

6. Apparatus as claimed in Claim 5 in which the clearance is arranged to be less than 50 mm.

7. Apparatus as claimed in Claim 6 in which the clearance is arranged to be less than 40 mm.

8. Apparatus as claimed in Claim 7 in which the clearance is arranged to be less than 30 mm.

9. Apparatus as claimed in Claim 8 in which the clearance is arranged to be in the region of 25 mm.

is 10. Apparatus. as claimed in any preceding claim in which the hot air supply means is arranged to supply air at a temperature greater than 1OCC. 11. Apparatus as claimed in Claim 10 in which the temperature is arranged to be greater than 1400C. 12. Apparatus as claimed in Claim 11 in which the 10 temperature is arranged to be greater than 1700C. 13. Apparatus as claimed in any preceding claim in which the hot air supply means is arranged to supply air to a temperature less than 3500C. is 14. Apparatus as claimed in Claim 13 in which the temperature is arranged to be less than 3000C. is. Apparatus as claimed in Claim 14 in which the 20 temperature is arranged to be less than 2500C.

16. Apparatus as claimed in Claim 15 in which the temperature is arranged to be less than 2000C.

17. Apparatus as claimed in any preceding claim in which the hot air supply means is arranged to supply air at greater than atmospheric pressure.

18. Apparatus as claimed in any preceding claim in which the outlet means comprises at least one nozzle.

16 19. Apparatus as.claimed in Claim 18 in which a plurality of nozzles are provided for each product. 20. Apparatus as claimed in Claim 18 or 19 in which the 5 area of the outlet of the nozzle or nozzles for each product relative to the upwardly facing surface of that product is arranged to be in a ratio greater than 1:4.

21. Apparatus as claimed in Claim 20 in which the ratio is greater than 1:5.

22. Apparatus as claimed in Claim 21 in which the ratio is greater than 1:6.

23. Apparatus as claimed in any of Claims 20 to 22 in which the ratio is in the region of 1:7.

24. Apparatus aj claimed in any of Claims 19 to 23 in which the ratio is less than 1:10.

25. Apparatus as claimed in any preceding claim including at least one gas burner located underneath the outlet means with the gas burner being arranged to direct a flame upwardly.

26. Apparatus as claimed in Claim 25 in which the outlet means are arranged to be of f set f rom the or each gas burner located beneath the outlet means whereby gas exiting the outlet means does not impinge directly on the or each gas burner located beneath the outlet means.

17 27. Apparatus as claimed in any preceding claim in which the outlet means includes more than one outlet.

28. Apparatus as claimed in Claim 27 in which at least two of the outlets are arranged to emit air supplied from a different supply region.

29. Apparatus as claimed in Claim 28 in which each supply region is arranged to have air supplied from a common source.

30. Apparatus as claimed in any preceding claim in which the outlet means is arranged to conform generally to the shape of the upwardly facing surface of a food is product to be processed.

31. Apparatus as claimed in any preceding claim including a conveyor arranged to cause movement of a product past the outlet means.

32. Apparatus as claimed in Claim 31 in which the conveyor is arranged to cause successive products to be moved past the outlet means.

33. Apparatus as claimed in Claim 32 in which the movement is arranged to be in a stepwise fashion.

34. Apparatus as claimed in Claim 32 in which the movement is arranged to be a continuous movement.

35. Apparatus as claimed in any of Claims 31 to 34 in which the conveyor is arranged to have a plurality of products extending in a row across a conveyor and 18 those products in that row are arranged to be spaced from each other.

36. Apparatus as claimed in Claim 35 in which the outlet means are arranged to direct air at each product in the row but not at locations between the products in the row.

37. Apparatus as claimed in any preceding claim including a plurality of outlet means that are arranged to successively direct air at the same product.

38. Apparatus as claimed in any preceding claim arranged to have air removed from around the side of the outlet is means.

39. Apparatus as claimed in any preceding claim arranged to have air removed from around the complete periphery of the outle means.

40. Apparatus as claimed in Claims 38 or 39 in which the air that is arranged to be removed is arranged to be removed in an upwards direction.

41. Apparatus as claimed in any of Claims 38 to 40 in which the air is arranged to be removed by creating a pressure in the region of atmospheric pressure or slightly less than atmospheric pressure. 30 42. Apparatus as claimed in any of Claims 38 to 41 including means for recycling at least part of the air that has been removed to the outlet means again.

19 43. Food processing apparatus substantially as herein described with reference to, and as shown in any of Figures 1 to 5 of the accompanying drawings.

44. A method of processing food comprising directing hot air at the upwardly facing surface of a food product.

45. A method as claimed in Claim 44 comprising directing air at the surface of the food product greater than 10 M/S.

46. A method as claimed in Claim 44 or 45 comprising pressurising air in order to direct air at the surface of a food product.

is 47. A method as claimed in any of Claims 44 to 46 comprising directing air from a plurality of outlets at the upwardly facing surface of the food product.

48. A method as claimed in any of Claims 44 to 47 comprising directing air at the food product with the air that is so directed conforming to the shape of the food product. 25 49. A method as claimed in any of Claims 44 to 48 comprising directing air at a spaced row of food products with air being directed at each food product but not, to any substantial extent, in the spaces between the food products. 30 50. A method as claimed in any of Claims 44 to 49 comprising removing air that has been directed at the surface of the food product.

51. A method as claimed in any of Claims 44 to 50 comprising moving the food product relative to hot air that is able to be directed in order to cause the food product to have different regions of hot air directed at it.

52. A method as claimed in any of Claims 44 to 51 in which the food product is stationary during at least part of the time that hot air is directed at the food product.

53. A method as claimed in any of Claims 44 to 52 comprising passing the food product through at least two streams of hot air that are directed towards the is upwardly facing surface of the product with at least.

one of those streams of hot air having at least a partial cooking effect on the product.

54. A method as claimed in any of Claims 44 to 53 comprising browning or toasting the surface of the food product with the downwardly directed hot air.

55. A method as claimed in Claim 54 comprising controlling the hot air to vary the amount of browning or toasting of a product or to maintain the same browning or toasting of the product.

56. A method of processing food substantially as herein described with reference to, and as shown in any of the accompanying drawings.

57. A food product that has been processed by a method as claimed in any of Claims 44 to 56.