GB2082447A - Cooking apparatus and method - Google Patents

Abstract

A cooking apparatus suitable for cooking particulate foodstuffs, such as chips, comprising an elongate source of radiant heat, e.g. infra-red heaters 16, a drum 12 for retaining said foodstuffs adjacent said source, a helix 14a, 14b and a rib 20 for advancing said foodstuffs along said retaining means, and means for cascading said foodstuffs within said retaining means, the arrangement being such that in use foodstuffs placed in one end of said retaining means are advanced therealong and cascaded therein to emerge cooked at the other end thereof. The drum 12 may be rotary or stationary; in the latter case the helix and the rib rotate to produce the cascading action. A blower fan 28 is provided. The helix may be replaced by vanes. <IMAGE>

Description

SPECIFICATION Cooking apparatus and method This invention relates to a continuous cooking apparatus and method for cooking particulate foodstuffs. More particularly it relates to a cooker for preparing potato chips without using a deep fat frying process.

There are many disadvantages to the preparation of deep fat fried particulate foodstuffs such as potato chips. The cost of the fat itself is very high and the fat is progressively degraded owing to the high temperatures employed. There is a major cost in electricity for heating the fat to cooking temperatures and finally there is the problem of discharging the smoke and odours from a deep fat fryer.

It is an object of this invention to go some way toward obviating these disadvantages or at least to offer the public a useful choice.

It is known to use radiant heat elements in association with conveying systems. However the disadvantage with existing such systems is that the radiant heat comes from one direction and the unexposed sides of foodstuffs are not cooked to the same degree as the exposed sides.

It is a further object of this invention to go some way towards overcoming this disadvantage or at least to offer the public a useful choice.

Accordingly, the invention may be said broadly to consist in cooking apparatus for particulate foodstuffs comprising an elongate source of radiant heat, means for retaining said foodstuffs adjacent said source, means for advancing said foodstuffs along said retaining means and means for cascading said foodstuffs within said retaining means, the arrangement being such that in use foodstuffs placed in one end of said retaining means are advanced therealong and cascaded therein to emerge cooked at the other end thereof.

Preferably said elongate source of radiant heat is a single resistance electric heater element.

Alternatively said elongate source of radiant heat comprises multiple bar resistance electric heater elements having an associated concave reflector.

Preferably said heater element(s) emit(s) infrared radiation.

Preferably said means for retaining said foodstuffs adjacent said source comprises an elongate cage structure open at either end thereof.

Preferably said cage structure has a wire mesh surface.

Alternatively said cage structure is expanded metal.

Alternatively said cage structure comprises perforated metal sheeting.

Preferably said cage structure is cylindrical.

Alternatively said cage structure has a square or rectangular section.

Alternatively said cage structure has a polygonal section.

Alternatively said cage structure has a elliptical section.

Preferably said advancing means comprises a helix on the inside of said retaining means.

In one embodiment said helix rotates to advance foodstuffs while said retaining means remains stationary.

In another embodiment said helix is fixed to the inside surface of said retaining means and rotates therewith.

Preferably said helix has a variable pitch, the smallest pitch being in the area where the cooking is conducted for the longest length of time.

Preferably said helix is in segments.

Preferably said cascading means comprises said helix and said retaining means.

Preferably said cascading means comprises a single rib projecting inwardly toward the longitudinal axis of said retaining means from the inner surface thereof.

Preferably said rib is substantially parallel to said longitudinal axis.

Alternatively there are at least a pair of said ribs.

Preferably there is included a source of forced air blowing through said retaining means.

Preferably said source is directed substantially along the path of said helix.

Preferably there is included heating means in association with said source of forced air for heating said forced air to the temperature of air adjacent said source of radiant heat.

In another embodiment the invention may be said broadly to consist in a method of cooking particular foodstuffs which comprises feeding particular foodstuffs into a retaining area adjacent a source of infrared radiation, cascading said particulate foodstuffs in said retaining area so as to expose all surfaces of said foodstuffs to said infrared radiation for a predetermined cooking time, advancing said foodstuffs along said retaining area and discharging said particulate food stuffs from said retaining area.

The invention may be more fully understood by having reference to the accompanying drawings in which: Figure 1 is a side elevation with parts broken away of a preferred embodiment of the invention.

Figure 2 is a plan view of a helix segment according to the invention manufactured from a metal disc.

Figure 3 is the section view Ill-Ill of an alternative arrangement of the heating element.

Figure 4 is a fragmentary sectional view of a feeding device for feeding the embodiment illustrated in Fig. 2.

Figure 5 is a fragmentary isometric view of an alternative drum construction employing vanes instead of a helix.

The cooker comprises an outer casing 10 made of stainless steel or the like provide with suitable insulation on the inside. Within said casing 10 is a foodstuff retaining means in the form of a cylindrical drum or cage 1 2 having a mesh, perforated metal sheeting or expanded metal outer surface 1 3. In one embodiment the drum 1 2 is rotatable as will be described below while in another embodiment it is stationary.

Mounted with the drum 12 is a helix 14a and 14b. The surface 1 3 and helix 1 4a and b are preferably of stainless steel and may have a non-stick surface. Typically a drum 1 2 would be approximately 1 m long and 350 mm in diameter. The pitch of helix 14 would be approximately 1 50 mm in the area of 14b.

In an alternative construction helix 14 is divided into a number of segments for easier removal for cleaning. The segments can be in registry with one another or spaced from one another.

In a still further alternative construction the pitch of the helix 14 is constant at about 1 50 mm and the drum 1 2 has the dimensions stated above.

A preferred mode of construction of a helix is shown in Fig. 2. A disc 21 of stainless steel or the equivalent has a central circular protion 23 removed. A slot 25 is cut from the circumference to the centre and holes 27 drilled for rivets or bolts. The disc 21 is then twisted into a helix segment. Adjacent segments are bolted or rivetted together and the end helix pieces bolted or rivetted to the frame of the drum 12 at each end.

Extending through the centre of drum 1 2 is a source of radiant energy such as a glass spherical resistance heating element 16. Alternatively a looped resistance heating element such as is used for grilling in an oven may be used. A preferred heating element is illustrated in Fig. 3. A cylindrical reflector 1 9 with a segment of one third to one half of its circumference cut away is provided within drum 1 2 in place of single element 1 6. Four resistance heating elements 1 6 which emit infrared radiation are fitted in the positions shown adjacent reflector 1 9.

In one embodiment a single rib 20 is fixed along the inside edge of drum 1 2 in a direction parallel to the longitudinal axis of the drum. This rib 20 is optional for reasons to be explained below. A pair of ribs may be em ployed but they have the disadvantage of creating more mechanical handling of the chips.

A means of reducing heat loss and means for assisting the cascading of food passing through the drum 1 2 is provided by a blower fan 28 which communicates with a slot 30 along the bottom of the drum 1 2. Blower fan 28 is driven through a motor 26. Drive is also taken from motor 26 through reduction box 24 to drive a main shaft 22. Air is continuously recirculated within casing 10, through inlet orifice 29, past fan 28 and out discharge slot 30.Slot 30 is provided with baffles to direct air along substantially the path followed by the helix 1 4. The baffles and ducting are arranged to avoid blowing directly at the heating element 1 6 as the foodstuffs could suffer local burning if they contacted the heating element 1 6. Reflector 19 also services to avoid contact of clips with element 16.

There is an opening 32 at the feeding end of casing 10 and an opening 34 at the discharge end thereof. Chips 1 8 are fed by conveyor 36 onto lip 38 which feeds them into the drum 1 2. Cooked chips are discharged out lip 40 at the discharge end 34 of drum 12.

In the embodiment illustrated an annular frame member 1 5 is provided around the circumference at each end of drum 1 2. Each frame member 12 is mounted in a bearing block 1 7. This arrangement leaves orifices 32 and 34 open to allow charging and discharging of the foodstuffs. A friction driving wheel 29 contacts and rotates frame member 1 5.

Wheel 29 is mounted at the end of driving shaft 22. In operation a charge of particulate foodstuffs 1 8 such as potatoes cut into the form of chips is fed along conveyor 36 and onto lip 38 of inlet 32. Foodstuffs 18 can be preheated by a source of radiant heat if desired or alternatively can even be fed in a frozen condition into the drum 1 2. The helix 14a is of a small pitch so as to advance the foodstuffs as slowly as possible at the begin ning of the cooking process.

In the embodiment where drum 1 2 rotates with rib 20 and helix 14 of the combined action of the ribs 20 and helix 14 serves to lift the foodstuffs 1 8 through a portion of a rotation of the drum until they cascade again to the floor of the drum. The cascading action is assisted by the blowing of air through the bottom slot 30 of the drum by means of blower fan 28. However, this blower fan is an optional integer and there is sufficient cascading action provided by the elements in the drum alone.

In an alternative embodiment a drum is stationary and helix 14 and rib 20 rotate to produce a cascading action which is substan tially the same as that described above. In the embodiment illustrated one single rib 20 is provided but it will be appreciated that a number of ribs extending the length of drum.

1 2 or shorter ribs between the helix member≈can be provided to serve a cascading function.

The cascading function is provided to ensure that the foodstuffs are cooked on all sides. Complete cooking is also assisted by providing for ducting so that the air being circulated via fan 28 along duct 30 is heated to substantially the same temperature as air next to heating elements 1 6.

As the foodstuffs become more and more cooked they are advanced at a higher rate out of the discharge end 34 of the drum 1 2 and down lip 40. Helix portion 1 4b has a longer pitch to advance the foodstuffs out of the mouth 34 of the cooker at a rate quicker than they are advanced in the area of helix portion 14a.

In a typical operation cooking time would be in the order of 6 minutes but residence time in the area of helix portion 14a would be approximately two thirds of this.

in the embodiment illustrated in Fig. 4 an endless conveyor 42 is provided adjacent the casing 10 of the apparatus. An endless belt 44 having dividers 46 across the face thereof is driven in the conveyor. A hopper 46 is provided to feed particulate foodstuffs such as potato chips 18 as illustrated. A hub 48 having vanes 50 projecting radially outward therefrom is provided adjacent the end of one leg of travel of conveyor 42. Sprocket wheel 43 drives both the conveyor 42 and the drum 48. A shute 52 is positioned near the end of a conveyor 42. A lip 54 feeds into the drum 1 2. In operation chips 1 8 are fed into hopper 46 and conveyed along the upper leg of belt 44 in compartments created by dividers 46.

Vanes 50 are synchronised with the operation of the drum 1 2 so that a vane 50 stacks up a supply of foodstuffs while a portion of a helix 1 4a is across the opening into the drum 1 2.

Vane 50 then releases the stacked up of chips and it falls into the open of the drum 1 2.

In the embodiment illustrated in Fig. 5 there are no helixes provided. Rather a series of vanes 56 are positioned on the sides of the drum at an angle shown whereby they achieve both a cascading and an advancing action. In a still further embodiment the drum 12 of either Fig. 1 or Fig. 5 may be tilted at a slight angle from the infeed and to the outfeed.

This invention can be used in combination with other known conveyor cookers for preparing such foodstuffs as fish in a batter. Heat generated can be used with heat exchangers in associated dishwashers or the like to maximise use of energy.

It will be seen that cost savings available with the apparatus according to this invention include the savings of cooking oil and the cost for heating the cooking oil. It has been observed that potato chips and fish and chicken pieces of an acceptable quality have been prepared through using the apparatus of this invention.

Claims (18)

1. A cooking apparatus suitable for cooking particulate foodstuffs comprising an elongate source of radiant heat, means for retaining said foodstuffs adjacent said source, means for advancing said foodstuffs along said retaining means and means for cascading said foodstuffs within said retaining means, the arrangement being such that in use foodstuffs placed in one end of said retaining means are advanced therealong and cascaded therein to emerge cooked at the other end thereof.

2. An apparatus according to claim 1 wherein said elongate source of radiant heat is a resistance electric heater element.

3. An apparatus according to claim 1 or claim 2 wherein said means for retaining said foodstuffs adjacent said source comprises an elongate cage structure open at either end thereof.

4. An apparatus according to claim 3 wherein said cage structure has a wire mesh surface.

5. An apparatus according to claim 3 or claim 4 wherein said cage structure is cylindrical.

6. An apparatus according to any one of the preceding claims wherein said advancing means comprises a helix on the inside of said retaining means.

7. An apparatus according to claim 6 wherein said helix rotates to advance foodstuffs while said retaining means remains stationary.

8. An apparatus according to claim 6 wherein said helix is fixed to the inside surface of said retaining means and rotates therewith.

9. An apparatus according to any one of claims 6 to 8 wherein said helix has a variable pitch, the smallest pitch being in the area where the cooking is conducted for the longest length of time.

1 0. An apparatus according to any one of claims 1 to 4 wherein said cascading means comprises a single rib projecting inwardly toward the longitudinal axis of said retaining means from the inner surface thereof.

11. An apparatus according to any one of the preceding claims inclu.ding a source of forced air blowing through said retaining means.

1 2. An apparatus according to claim 11 which includes heating means in association with said source of forced air for heating said forced air to the temperature of air adjacent said source of radiant heat.

1 3. An apparatus for cooking particulate foodstuffs substantially as herein described with reference to the accompanying drawings.

14. A method of cooking particulate foodstuffs which comprises feeding particulate foodstuffs into a retaining area adjacent a source of infrared radiation, cascading said particulate foodstuffs in said retaining area so as to expose all surfaces of said foodstuffs to said infrared radiation for a predetermined cooking time, advancing said foodstuffs along said retaining area and discharging said parti culate foodstuffs from said retaining area.

15. A method according to claim 14 wherein said particulate foodstuffs are fed on an endless conveyor and are preheated prior to discharging them into said retaining area.

16. A method according to claim 14 or 1 5 wherein said cascading is effected in a drum.

1 7. A method according to any one of claims 14 to 1 6 wherein said cascading is effected by blowing warm air into said retaining area from below said retaining area.

18. A method of cooking particulate foodstuffs, substantially as herein described with reference to the accompanying drawings.

1 9. A method of cooking particulate foodstuffs, which comprises passing said foodstuffs through the apparatus defined in any one of claims 1 to 13.