WO2009010900A2

WO2009010900A2 - Juice extractor

Info

Publication number: WO2009010900A2
Application number: PCT/IB2008/052750
Authority: WO
Inventors: Markus Schlagbauer; Thomas Sigot
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2007-07-17
Filing date: 2008-07-09
Publication date: 2009-01-22
Also published as: WO2009010900A3

Abstract

A centrifugal bowl (106) for food processing comprising a base that can be detachably mounted on the motor shaft (114) to rotate about an axis of rotation, a filter portion in the shape of a perforated peripheral side sieve wall extending from an open end to the base and wherein the shape of the perforated peripheral side sieve wall is non- linear and cutting teeth disposed on the inner side of the base, the diameter of the base being smaller than the diameter of the open end is disclosed. The disclosed centrifugal bowl is useful for all juicers which extract liquid from solid. The juice output of continuous centrifugal juicers can increase since the non- linear sieve wall provides a higher force gradient to the sieve wall.

Description

Juice Extractor

FIELD OF THE INVENTION:

The subject matter relates to a food processor for extracting liquids from fruits and/or vegetables and more specifically to the filter sieve arrangement in the food processor.

BACKGROUND OF THE INVENTION:

Patent document WO2005110173 discloses a double action sieve for juice extractors. The disclosed double action sieve comprises a cone with a steeper angle put onto the base cone.

It would be advantageous to have a simple filter sieve arrangement that can increase the juice output.

SUMMARY OF THE INVENTION: A centrifugal bowl for food processing comprising a base that can be detachably mounted on the motor shaft to rotate about an axis of rotation, a filter portion in the shape of a perforated peripheral side sieve wall extending from an open end to the base and wherein the shape of the perforated peripheral side sieve wall is non- linear and cutting teeth disposed on the inner side of the base, the diameter of the base being smaller than the diameter of lhe open end is disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS:

The above-mentioned aspects, features and advantages will be further described, by way of example only, with reference to the accompanying drawings, in which the same reference numerals indicate identical or similar parts, and in which: Fig. 1 shows an exemplary juicer comprising a centrifugal bowl; Fig. 2 shows the various parts of the exemplary juicer of Fig. 1 ; Fig. 3 schematically shows the force of a particle on an exemplary centrifugal bowl arrangement; Fig. 4 is a schematic graph showing the relation ship between a straight filter sieve and a non-linear filter sieve with respect to the radial squeezing acceleration over the radius; Fig. 5 schematically shows the principle of working of the centrifugal bowl according to an embodiment of the subject matter; and

Fig. 6 shows a juicer comprising the centrifugal bowl according to an embodiment of the subject matter. The term food processor here refers to a kitchen appliance used for shredding or blending or slicing food and extracting liquids (i.e.extracting liquids from solids).

Referring now to Fig. 1, a juice arrangement 1000 is generally provided in the form of a motor driven domestic appliance capable of extracting the juice from fruits (orange, lemon, grapefruit), especially citrus fruits, and delivering the juice into a vessel positioned adjacent the main body of the appliance.

Such juicer appliances typically incorporate one or more filters, configured and located to retain solid, or semi-solid, materials such as pith, partly because the presence of undue amounts of such materials in the prepared juice is considered unpalatable by many users and partly because such materials tend to block outlet ducts, which thus require frequent cleaning.

Referring now to Fig. 2, the juicer 1000 comprises:

1. Pusher 100

2. Feeding tube 102

3. Lid 104 4. Centrifugal bowl (anodized aluminum or stainless steel micro mesh filter) 106

5. Juice collector 108 with a spout

6. Pulp container 110

7. Control knob 112

8. Motor shaft 114 9. Motor unit 116

10. Juice jug 118

11. Clamps 120

A motorized base unit 116 has an upper surface from which protrudes a motor shaft 114, the upper surface adapted to receive a juice collector 108. The juice collector 108 has a central opening for admitting the motor shaft 114 and has two nested portions namely an outer pulp collection portion and an inner juice collection portion with a spout. The juice collector 108 has a lid 104 with a feeding tube 102. A frusto-conical centrifugal bowl 106 resides with in the juice collector 108 below the feeding tube 102. A pusher 100 is used to feed the fruits and/or vegetables into the feeding tube 102. A juice jug 118 and a pulp container 110 are provided to collect the extracted juice and the pulp. The operation of the juicer 1000 is explained below:

Step 1: Place the centrifugal bowl 106 in the juice collector 108 and mount the centrifugal bowl 106 securely onto the motor shaft 114

Step 2: Place the lid 104 over the juice collector 108

Step 3: Snap the two clamps 120 onto the lid 104 to lock into place

Step 4: Place the juice jug 118 under the spout adjacent to the main body of the juicer

Step 5: Cut the fruit/vegetables into pieces that fit into the feeding tube 102 and make sure that the juice jug 118 has been placed under the spout

Step 6: Place the pulp container 110 appropriately

Step 7: Switch the juicer by turning the control knob 112

Step 8: Put the cut pieces in the feeding tube 102 and gently press them towards the rotating centrifugal bowl 106 by means of the pusher 100 Step 9: Slide the pusher 100 into the feeding tube 102 by aligning the groove in the pusher with the small protrusion on the inside of the feeding tube

In operation, the centrifugal bowl 106 rotates. The shredded fruit pieces are transported along the micro mesh filter. The filter mesh (small holes on the sieve) separates juice and fruit fibers. The juice flows through the sieve holes and into the juice collector 108. Through the spout the juice flows directly into the juice jug 118. Further, the solid fruit fibers will spin out of the sieve directly into the pulp container 110.

Juicers have a certain juice output. The juice output here refers to the ability to retrieve a fraction of juice of all the juice that can be extracted from a certain fruit. In a first step, the fruit is grated and in a second step the juice is extracted from the grated material which is generally a mixture of juice and pulp. The mechanism where the separation of the pulp and the juice takes place is the centrifugal bowl 106, which rotates with a considerable speed.

The juicers have a limited efficiency in terms of their juice output. Hence, it would be advantageous to have more juice per unit weight. Referring now to Fig. 3, the particle (i.e. fruit or vegetable) from which the juice is to be extracted is put into the centrifugal bowl 106. Once the centrifugal bowl 106 starts rotating, there will be two parts of centrifugal force acting on the particle namely i. the first part of the centrifugal force F_p that squeezes out the fruit; ii. the second part of the centrifugal force F_c that moves the fruit shred into a pulp container.

The fraction of these two forces depends on the angle of the wall of the centrifugal filter sieve. The resulting centrifugal force increases with the radius. Therefore, the shred is accelerated a faster towards the edge of the filter sieve. This faster acceleration a would not be necessary and therefore a solution may be advantageous where the acceleration stays constant while the squeezing force grows.

DETAILED DESCRIPTION OF THE EMBODIMENTS: Accordingly, a centrifugal bowl for food processing comprising a base that can be detachably mounted on the motor shaft to rotate about an axis of rotation, a filter portion in the shape of a perforated peripheral side sieve wall extending from an open end to the base and wherein the shape of the perforated peripheral side sieve wall is non- linear and cutting teeth disposed on the inner side of the base, the diameter of the base being smaller than the diameter of the open end is disclosed.

With the disclosed centrifugal bowl the acceleration into the radial direction can remain constant. Therefore, the residence time on the sieve can be longer and the radial force onto the sieve (i.e. the actual squeezing force) can increase with a higher non-constant gradient. The term non- linear here refers to a curved, a bended, a circular and/or a segment of a sphere shape.

Referring now to Fig. 4, the horizontal axis represents the radius in mm (of the base of the centrifugal filter sieve) and the vertical axis represents the acceleration m/s². The graph shows the acceleration on the particle placed on the centrifugal curved (i.e. non-linear) filter sieve 106 in comparison with a centrifugal straight filter sieve. In the case of the straight filter sieve, the acceleration parallel to the sieve and normal to the sieve increase linearly with respect to the radius. In the case of the curved filter sieve, the tangential acceleration stays constant or even decreases and the acceleration normal to the sieve wall increases non- linearly. The maximal force on the particle can be approximately 10% higher compared to the straight sieve and therefore the juice output can increase.

Referring now to Fig. 5, the perforated peripheral side sieve wall of the centrifugal bowl 106 has to be built in a non- linear manner (i.e. round form, a circular form, bended form and/or segment of a sphere). The acceleration A tangential to the sieve wall is constant or even becomes lower from the inside to the outside. Therefore, the force F_maxcan be 10% higher resulting in higher juice output. In other words, having a non- linear wall creates a higher force gradient to the sieve wall.

Further, the disclosed shape of the perforated peripheral side sieve wall allows better squeezing of the pulp to obtain higher juice output. The effect of the shape is that the pulp will traverse slower to the edge whilst at the same time greater pressure is applied to the pulp.

The movement time of the particle on the perforated peripheral side sieve wall can be longer and the radial force onto the sieve (the actual squeezing force) can increase with a higher non-constant gradient. The movement time of the particle on the rotatable perforated peripheral side sieve wall can increase approximately from 10 milli seconds to 12 milli seconds and hence the traversal path on the filter sieve will become approximately 10% longer. The acceleration of the particle into the rotation direction can improve.

In an embodiment, the shape of the perforated peripheral side sieve wall is brachistrone. Brachistrone here refers to the curve along which a particle takes the least time to travel between two points. The advantage of the brachistrone would be, that the time on the way up takes the longest of all curves (the way down is the shortest), therefore each food particle stays the longest on the sieve and is squeezed out for a longer time. Furthermore, the force on the particle is the highest possible. In a still further embodiment, the perforated peripheral side sieve wall is flexible (i.e. it can assume optimal shape automatically). The advantage of this embodiment is that the production process is much easier and the brachistrone mentioned in the previous embodiment might already be selected as a form. Further, the material of the sieve wall can be selected such that the sieve wall takes optimal shape based on the mass of the food particle and the rotational speed.

In the case of the exemplary centrifugal bowl arrangement 106 shown in Fig. 5, the inner radius (i.e. base) is approximately 50 mm and the outer radius (i.e. open end) is approximately 68 mm. For such an arrangement, the construction of the perforated peripheral side sieve wall in a non- linear manner can result in an angle to the vertical line (Cf. Fig. 6) in the range of about 32.5° on the inside to 28.0° at the outside.

Fig. 6 shows an exemplary juicer. The various parts of the juicer namely pusher, feeding tube, lid, juice collector, motor shaft and motor unit are known from the patent document WO2005002404 which is incorporated herewith by reference. The disclosed centrifugal bowl which is shown by the reference numeral 106 can be used in the juicer to increase the juice output.

In summary, the juice output of continuous centrifugal juicers can be increased by generating a higher force gradient to the sieve wall. The higher force gradient can be achieved by a non-linear sieve wall. Further, the disclosed centrifugal bowl is simple in construction when compared to the double action sieve disclosed in the patent document WO2005110173, since there is no need to glue the sieves and balance the sieves since there is only one sieve.

The disclosed non-linear filter sieve can be used in all juice extractors that use the principle of centrifugal juicing and can increase the juice output. Although the disclosed filter sieve is applicable to juicers, it may be applied to any food processing apparatus which extracts liquid from solid.

While the subject matter has been illustrated in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the subject matter is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art of practicing the claimed subject matter, from a study of the drawings, the disclosure and the appended claims. Use of the verb "comprise" and its conjugates does not exclude the presence of elements other than those stated in a claim or in the description. Use of the indefinite article "a" or "an" preceding an element or step does not exclude the presence of a plurality of such elements or steps. The Figures and description are to be regarded as illustrative only and do not limit the subject matter. Any reference sign in the claims should not be construed as limiting the scope.

Claims

CLAIMS:

1. A centrifugal bowl for food processing comprising:

- a base that can be detachably mounted on the motor shaft to rotate about an axis of rotation;

- a filter portion in the shape of a perforated peripheral side sieve wall extending from an open end to the base and wherein the shape of the perforated peripheral side sieve wall is non- linear; and

- cutting teeth disposed on the inner side of the base, the diameter of the base being smaller than the diameter of the open end.

2. The centrifugal bowl for food processing as claimed in claim 1 , wherein the shape of the perforated peripheral side sieve wall is brachistrone.

3. The centrifugal bowl for food processing as claimed in claim 1, wherein lhe perforated peripheral side sieve wall is flexible.

4. The centrifugal bowl for food processing as claimed in claim 1, wherein the diameter of the open end is 136 mm and the diameter of the base is 100 mm and the angle of the perforated peripheral side sieve wall relative to the axis of the rotation is in the range of about 32.5° at the base end to 28.0° at the open end.

5. A centrifugal bowl for food processing as claimed in claim 1 , wherein the food processing comprises juice extraction.

6. A juicer comprising the centrifugal bowl as claimed in claim 1.