From W09703596 and US patent No. 6,062, 132 a cooking apparatus is known (cooking including frying), which uses a wheel and a number of baskets with food suspended from the wheel. A lower part of the wheel is immersed in a frying oil bath and the wheel is rotated around its axis so that the baskets carry the food into the frying oil. When food has to be fried a basket is first filled, then attached to the wheel and after the food has been fried the basket is detached from the wheel.

The wheel is provided with a number of lids that remain suspended from the wheel when a basket is detached. Each lid is rotatably suspended from rods that are attached to wheel. The baskets have hoops that are hung around the rods, with the lid in between the rod and the basket. Thus, the lid prevents food from drifting out of the basket when the basket is lowered into the oil.

Although this type of frying apparatus works reasonably well, there is room for improvement of the quality of the fried food. Also it is desirable to simplify cleaning of the apparatus.

Summary of the invention Among others it is an object of the invention to improve the quality of fried food, in particular of French fries.

Among others it is an object of the invention to simplify cleaning of the apparatus.

Among others, it is an object of the invention to provide for a food heating apparatus wherein no sudden cooling of a basket of food occurs.

Among others, it is an object of the invention to provide for a food heating apparatus wherein with a predetermined amount of available heating power a greater amount of food can be heated.

It is a further object of the invention to do so in a frying apparatus.

Among others it is an object of the invention to provide for heating baskets of food in an apparatus that works in a continuous process.

Among others it is an object of the invention to provide for heating of food in a way that allows stray food to be removed from the surface.

Among others it is a further object of the invention to do so in a way that costs little energy.

The invention provides for a food heating apparatus according to Claim 1. By connecting baskets with food at a fixed orientation to a wheel, so that the baskets turn over relative to the axis of gravity when the wheel rotates, it is ensured that the food slowly turns over when immersed in the heating fluid. Thus, the food will be evenly heated and a minimum of damage is done by turning over.

In an embodiment, the wheel assembly contains a lid surface that extends along at least part of a cylindrical surface around the axis of the wheel assembly. The lid surface closes off open loading sides of the baskets when the baskets are connected to the wheel, to prevent the food from falling out of the baskets when they are turned over. Preferably, the lid surface comprises a mesh that detains the food but passes the heating fluid, such as oil. Similarly, the baskets also preferably also contain a mesh that permits the heating fluid to pass.

Preferably the baskets having side walls diverging from one another towards the open top side, so that successive baskets with their to surfaces against the lid surface substantially fill a sector of the wheel assembly. In this way a high food processing capacity is realized.

Preferably, the lid surface comprises a plurality of individually detachable segments, each extending along a respective angle around the axis.

Thus, the lid segments, which have to be cleaned because they come in contact with the food, can easily be removed for cleaning. There is no need to remove the entire wheel assembly for cleaning the segments. The removable segments need not each cover a single basket. For example, each segment may serve to cover three baskets, or even just part of a basket. The lid segments may be hung on spokes of the wheel assembly. Thus a light construction is possible that facilitates removal of the wheel assembly.

The food heating apparatus is capable of processing food at a high throughput rate. Baskets with food can be inserted one after the other and removed again once they emerge on the wheel. Because the baskets are lowered slowly into the fluid, no sudden cooling occurs, which means that a nearly constant heating power suffices. No high peak heating capacity is needed. This means that standard power outlets can be used to process vast quantities of food. In many cases the throughput is so high that more than one operator is needed, for example one for inserting and removing food and another for dispensing food to eaters. In this case, the apparatus is preferably provided with a slide next to the wheel, for emptying the baskets in the slide, which leads to a counter for dispensing food. Thus, it is prevented that hot baskets have to be moved to the counter, with the risk of injury.

These and other objects and advantageous aspects of the heating apparatus and heating method according to the invention will become apparent from the attached drawing.

Figure 1 shows a frying apparatus Figure 2 shows a front view of the apparatus Figure 3 shows an overview of the frying apparatus Figure 4 shows a basket

Figure 5 shows a cage segment Figure 6 shows baskets inserted into the cage segment Figure 7 shows a side view of a basket in a cage segment Figure 8 and 9 show a spoke construction Figure 10 shows an axle assembly Figure 11 shows a wheel/lid assembly Figure 12 shows part of an overflow system Figure 13 shows a side view of an overflow Figure 14 shows a circulation system Figure 1 shows a frying apparatus. The apparatus contains an oil tanklO. A wheel assembly has spokes 17 extending from a hub 120 on the axle 121 of the wheel at the ends of spokes 17 a segmented lid 12 is provided, which comprises lid segments that extend between the spokes 17 along the perimeter of the wheel assembly (individual segments are indicated with circled numbers 1-5). Space for baskets 18 is provided adjacent to the lid segments 12, in a direction toward the axle 121. Electric heating elements 16 are provided in the tank 10, positioned under the wheel assembly. A sensor 13 is provided for sensing oil temperature. In the lower part of the tank 10, lower than the electric heating elements 16, a cold zone 15 is formed, which extends to an exhaust with a tap 11 at the lowest part of the tank 10.

Figure 2A shows a side view of the frying apparatus. The wheel assembly is visible extending above the walls of the tank.

Figure 3 shows a more detailed overview of a mobile frying apparatus for frying French fries, again showing the wheel assembly, with baskets 18 inserted in the wheel. Moreover the apparatus contains a circulation system for air and oil, with an oil reservoir 30, an oil filter 32, an oil pump 34 and an air circulation path with an outlet 36 at the bottom of the apparatus. Furthermore the apparatus contains a counter with a storage surface 380, heating lamps 382 for heating food on surface 380, a slide 384 for

sliding fried French fries onto the surface 380 and an inclined scoop plane 386 for scooping up French fries. The apparatus is provided with transport wheels 39 for mobile use.

In operation the tank 10 is filled with cooking oil 14 up to approximately half the height of the wheel assembly. The oil 14 is heated with the electric heating elements 16, so that a sensed temperature of the oil 14 reaches a set value, for example a regulated temperature in the range of 150- 220 degrees Celsius. A motor (not shown) coupled to the axle 121 of the wheel assembly drives the wheel assembly to rotate with a substantially constant slow speed of rotation (small interruptions of movement may be provided to load baskets, but this is not necessary when the speed is very slow). Instead of a motor, one may of course rotate the wheel by hand, for example using a handle, but of course a motor is more convenient and can more easily ensure constant speed.

Initially no baskets 18 are attached to the wheel assembly. An operator fills a basket 18 with food, for example with French fries, and inserts the basket 18 into a segment of the wheel assembly at a position where the basket 18 is not yet immersed in the oil 14. The operator may repeat this process for successive baskets, each time filling a basket and inserting it into a segment of the wheel assembly, at a next position for a basket 18 on the wheel, when this position becomes available as a result of slow revolution the wheel assembly. Thus, the wheel can be filled with baskets 18 over a substantially continuous arc.

As a result of rotation of the wheel assembly the baskets 18 are immersed one after the other into the oil 14. After passing about half a revolution of the wheel assembly the baskets 18 emerge again one after the other. The rotation speed of the wheel assembly is set so that the time interval during which. the baskets 18 remain in the oil from the moment of immersion to the moment of emergence ensures that the food is properly done after emergence.

When a basket 18 has emerged the operator pulls the basket 18 from the wheel assembly and drops the food from the basket into slide 384 from where it drops onto surface 380. From the surface the French fries can be scooped up and distributed. Use of slide 384 makes it unnecessary to move the hot basket close to surface 380, avoiding danger for another operator that is scooping up fried French fries from the surface 380.

Because the baskets 18 are immersed gradually, with the constant rotating speed of the wheel assembly, and the baskets 18 are substantially contiguous, a minimum variation of the oil level occurs as a result of immersion of the baskets 18. Because the baskets enter the fluid very slowly, the fluid does not cool suddenly. Therefore no excessively peaked heating power is required to maintain fluid temperature.

Because the baskets 18 have a fixed orientation relative to the wheel the food, for example French fries, is turned over gradually during frying.

From immersion to emergence the food is turned 180 degrees. Turning over ensures even frying of the food. Gradual turnover ensures that turnover causes a minimum of damage to the food, so that a minimum of damage is done to the food. On one hand this results in evenly fried, high quality French fries and on the other hand this ensures a minimum pollution of the oil by debris from the French fries.

Figure 4 shows the construction of a basket 18. The basket contains a wire frame 40 which is covered by a mesh 42 that leaves the basket open on one side 44. The basket 18 has handgrips 46 on one side. When using the handgrips 46 a user should wear heat-protecting gloves. Instead of using handgrips 46, of course a detachable handgrip may be used, which can be detached from the basket 18 while the basket is connected to the wheel assembly.

Figure 5 shows the construction of a lid segment. The lid segment 12 contains a mesh on the side of the periphery of the wheel assembly and a supporting wire frame 50 that divides the lid segment into identically shaped

sub-segments. The wire frame 50 has eyelets 52 on either side of the segment.

Each basket 18 fits into a sub-segment, between wires of the wire frame 50.

Figure 6 shows a part of a segment, with a first basket 18 inserted in to a segment and a second basket 18 with food 60 next to it in the process of being inserted or removed. A click detent is provided to retain the basket 18 in the sub-segment.

Figure 7 shows a side view of a basket 18 in the subsegment, with a protrusion 70 on the lid extending into the basket 18 to retain the basket 18 in the segment as long as no axial force is exerted. Preferably the separations between the sub-segments extend along part of radii of the wheel assembly and the baskets widen correspondingly towards their open side, so that the baskets can fill the entire periphery of the wheel assembly.

As will be appreciated the wire frame 50 of the segments 12 serves to retain the baskets 18 fixed to the wheel assembly at a fixed orientation. The click connection, using the protrusion serves as a further detent, to prevent axial movement of the baskets 18. However, it should be realized that other ways of connecting the baskets may be used. For example, clamps may provided on the wheel assembly to clamp the rear side of the basket 18 (the side opposite the handgrips 46) to the wheel assembly. As another example, the baskets 18 may be provided with small flanges extending on opposite side of one of the faces of the basket and the wheel assembly may be provided with slots for receiving these flanges. For example, flanges may be provided left and right of opening 44 (as viewed from the face with handgrips 46) and segments 12 may be provided with pairs of strips that run axially (parallel to axle 121) just below the mesh of the segments, to that the flanges on either side of a basket can hang on the strips to support and connect the basket. It will be appreciated that many other ways of connecting baskets to the wheel assembly are possible.

Preferably, a detector (not shown) is provided to detect excessive resistance against rotation of the wheel assembly, for example due to a basket

18 that has not been fully inserted. When the detector detects excessive resistance it commands the motor that rotates the wheel to stop or even reverse.

The wheel is assembled from an axle 121 with a hub 120 mounted on it, by inserting spokes 17 into the hub 120, and connecting the lid segments 12 to the radially extending parts of the spokes 17.

Figure 8 shows a spoke 17. The hub of the wheel assembly has slots 80 on its perimeter into which the spokes 17 fit. The spoke 17 are L shaped, with the top of the stem of the L inserted into the slot 80 and fixed therein, for example by welding. The spoke 17 has a hole 82 in the stem of the L for connecting eyelets 52 and in the horizontal part of the L notches 84 are provided for inserting wings 86.

Figure 9 shows a spoke 17 mounted on the axle 121 of the wheel assembly. The hub 120 is mounted on the axle 121 and the spoke 17 is mounted in the hub 120. Preferably, the axle 121 is made of two parts, with a detachable sleeve 90 connecting the parts. This makes it easy to remove the axle 121 from the apparatus.

Figure 10 shows the axle 121 and hub 120 carrying five spokes 17.

Figure 11 shows the wheel assembly with each lid segments 12 hanging between a respective pair of spokes 17. The segments 12 are suspended on the wings 86 that are inserted in the notches 84 on the short arm of the L. Eyelets 52 on the wire frame 50 of the segments 12 are used to connect the segments 12 to the long branch of the L through the holes 82 with a nut and bolt.

Further eyelets 52 are used to connect the wire frames of successive segments 12 on the side opposite the long branch of the L shaped spokes 17.

The lid segments 12, with the mesh that comes into contact with food are regularly disassembled from the wheel assembly for cleaning, e. g. in a washing machine. Because the wheel can easily be disassembled cleaning does not require much overhead. After cleaning the wheel assembly is readily reassembled, by hanging wings 86 in notches 84 of a pair of spokes 17 that

extend upward from hub 120, hanging lid segment 12 on wings 86. Eyelets 52 on one side of the lid segment 12 may be provisionally attached to the hole 82 of the spoke on one side of the lid segment 12. Next the wheel may be rotated so that the spoke 17 on the other side and the next spoke 17 after that extend upward. Wings 86 are hung on the next spoke 17 and a next lid segment 12 is hung on the wings 86. The eyelets 52 of this lid segment 12 are attached to the eyelets of the previous lid segment 12, one pair of eyelets 52 via the hole 82 in spoke 17. Subsequently this procedure is repeated until lid segments 12 have been hung full circle, the last lid segment 12 being attached to the first lid segments.

Thus this construction allows the lid segments 12 and the spokes 17 to be easily removed and reassembled for cleaning. On the other hand a maximum food processing capacity is realized, because successive the baskets 18 can substantially fill any part of the perimeter of the wheel assembly, since the lid segments extend over the entire perimeter.

Figure 12 shows an overflow construction. For an overview of the overflow system, one may refer to figure 3 as well. The tank 10 is shown with oil 14 in it. Next to the tank 10, oil overflow outlets 130 are provided that catch oil 14 that overflows from the tank 10 (e. g. due to a rise in the oil level upon immersion of food in the oil). Over the overflows 130 fat filters 132 are provided, in front of a gas suction channel.

Figure 13 shows a detail of the overflow. The fat filter 132 is arranged to filter oil droplets from gas sucked into the gas suction channel 134.

The fat filter 132 is mounted at a skewed angle over the overflow 130, so that oil that drips from the fat filter drips into the overflow and joins the overflowing oil current 136.

Figure 14 shows a circulation system. Overflowing oil is fed to a pipe 140, which leads to an oil filter 142. Preferably, the tap 11 at the bottom of the tank is also coupled to this pipe 140. The oil filter 142 outputs into an oil reservoir 144 at the bottom of the apparatus. A circulation pump 146 is

coupled to the oil reservoir 144 for pumping oil from the reservoir 144 to the top of the tank 10. The gas suction channel 134 feeds the hot gas that has been pumped from the top of the tank 10 down to flow around the reservoir 144 and out through a cleaning filter 148.

In operation, dependent on the amount of food in the baskets 18, the temperature of the food 60 and/or the presence of baskets 18 at all the oil 14 level in the tank 10 can rise with different speeds. The overflow 130 catches excessive rises and the overflowed fluid is recirculated later, when it is detected that the fluid level has fallen again. A fluid level detector (not shown) is preferably provided in the tank to activate the recirculation pump 146 for this purpose. The oil filter 142 filters stray food from overflowing fluid.

The reservoir 144 receives oil from the filter 142. The reservoir 144 may be used to add replacement fluid to the recirculating fluid. For this purpose an oil supply inlet (not shown) to reservoir 144 may be provided.

Frying oil is typically absorbed partly in the food, making it desirable to add replacement oil regularly, so as to make it possible to maintain the oil at a predetermined average level in tank 10. Replacement of the oil is thus realized together with circulation.

A gas pump 149 pumps gas from a region immediately over a top of the oil in the tank 10. The gas is used to heat oil in the reservoir 144. By pumping away gas (the gas contains air including oil and/or water vapor) from above the fluid smells and pollution are avoided. In addition the gas is used to keep up the temperature of overflowed fluid. Thus energy consumption is reduced. Preferably, an additional heater (not shown) is provided in the recirculation unit to heat the recirculated oil to at or near the temperature of oil in the tank 10 before supplying it to the tank 10.

The fat filter 132 between said region and the gas is provided for filtering oil from the gas before it enters the gas suction channel 134, the fat filter 132 being inclined at an angle to the vertical so that oil drips from a

lower filter surface of the fat filter 132 into the overflow 130. Thus oil losses are minimized.

Preferably the reservoir 144 is included in an enclosed space under the tank 10, for storing recirculating oil. The gas pump 149 is preferably arranged to pump gas from a region immediately over a top of the oil 14, the pumped gas being fed to the closed space for heating oil in the reservoir 144 with the pumped gas. This is an effective way of conserving energy.

Preferably the tap 11 at the lower part of the tank is coupled to the reservoir 144 via the oil filter 142. Thus stray food that settles a the bottom of the tank 10 may be passed from the tank 10 and filtered from the oil before entering the reservoir 144. Later the oil can be reused. Only one circulation system is needed for recirculating oil from the top and the bottom of the tank 10.

Preferably the apparatus comprises an emergency valve (not shown) in the drain connection of the tank 10 for draining the oil 14 into the reservoir 144 at an increased speed in case of an emergency. Thus the tank 10 can be emptied quickly into the reservoir 144 in case of fire for example.

Alternatively, valve 11 may be of a type that has a normal operating position, in which oil is drained at a low rate from the tank 10 sufficient to remove debris, and an emergency position, in which oil is drained at a higher rate to drain the oil from the tank 10 into the reservoir 144 as quickly as possible.

Preferably, the apparatus contains a fire extinguisher (not shown) fixed so that it is aimed a region above the surface of the oil, with a control to actuate it in case of emergency.

Although the invention has been described for frying French fries in oil, it will be appreciated that other food, or other heating fluid, such as water may be used.