GB2418341A

GB2418341A - Removing skins from nuts

Info

Publication number: GB2418341A
Application number: GB0421277A
Authority: GB
Inventors: John Prendiville
Original assignee: SULBY ENGINEERING Ltd
Current assignee: SULBY ENGINEERING Ltd
Priority date: 2004-09-24
Filing date: 2004-09-24
Publication date: 2006-03-29
Also published as: GB0421277D0

Abstract

An apparatus is disclosed for loosening or removing skin from particulate organic products such as nuts. The apparatus comprises parts 32 defining a set of chambers. Associated with each chamber is a nozzle 72, which ejects fluid into the chamber to remove skins from the product. The parts defining each chamber can be re-configured between two different configurations. In one the chamber is substantially enclosed to prevent egress over the products, although openings are provided so that the fluid ejected into the chamber can drain. In the other configuration the chamber is opened so that access is available to load the products to be treated into it.

Description

J

APPARATUS FOR LOOSENING OR REMOVING SKINS

OF PARTICULATE ORGANIC PRODUCTS

The present invention relates to an apparatus and a process for loosening or removing the skins of particulate organic products such as nuts, beans, seeds and the like.

Various natural foodstuffs carry a thin exterior skin which needs to be removed in the course of preparation. Manual skin removal is time consuming and machines for automated skin removal are known. Some such machines rely upon abrasion. For example with specific reference to nuts, devices are found in the prior art which scrub, brush or scrape the nut kernels to remove their skins. Such devices often do not provide for complete removal of the skins, for which reason electro-optical or manual sorting may be necessary in order to remove and re-treat those products whose skins remain adhered.

Most such processes involve pre-treatment of the nuts to loosen their skins and to facilitate removal. Known pre-treatments involve soaking or some form of heating process such as roasting or treatment with hot air, steam or heated water. Pre-treatment adds to processing time and can impair the quality of the product.

Another approach to skin removal involves exposing the products to a vigorous spray or jet of water. As an example of this approach, reference is directed in particular to US patent 6634283B2 (inventors Axel and Prendiville, assigned to James Foxdale Ltd.) which concerns an apparatus in which products such as nuts are loaded into trays which are shaped to provide a set of shallow, annular, upwardly open receptacles for receiving the products and are carried upon a conveyor in order to transport the products through a processing zone in which they pass beneath a bank of nozzles which eject high velocity water jets onto the products. The shapes of the receptacles in this known apparatus promote circulation of the products within the receptacles under the effect of the water jets, helping to ensure that all of the products are exposed to the jets and so providing a high percentage of skin removal. In an effort to prevent escape of products from the receptacles, a lid is provided to cover a bank of trays. Pneumatic actuators advance the lid downward onto a bank of trays in position beneath the nozzles, then withdraw it upwards after treatment so that it does not foul the trays as they are moved onward by the conveyor. The lid is in one example formed of mesh and in another appears to be a sheet component with holes through which the water jets pass.

Despite the success of this type of machine, there are important commercial incentives to improve upon its performance. One such concerns product wastage. The large throughput of expensive natural products means that even a small percentage reduction in wastage can result in a large cost saving. Maximising skin removal and reducing energy usage are also commercially important, In accordance with the present invention there is an apparatus for loosening or removing skin from particulate organic products, comprising parts for defining a set of chambers, each chamber having at least one associated nozzle for ejecting fluid into the chamber to effect skin removal, the parts defining each chamber being reconfigurable between an in-use configuration in which the chamber is substantially enclosed against egress of the products, although openings are provided for drainage of the fluid, and an open configuration in which access is available for loading of the products to be treated.

Specific 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 view from one side of a de-skinning apparatus embodying the present invention; Figure 2 is a perspective illustration from above and to one side of components within a processing zone of the de-skinning apparatus; Figure 3 is perspective illustration of one of a set of enclosures incorporated in the de-skinning apparatus shown in section to reveal showing a rotary nozzle head and related components within the enclosure;.

Figure 4 is a scrap view of the nozzle head, viewed from one side; Figure 5a is a perspective illustration, from above and to one side, of one of a set of trays used in the de-skinning apparatus; Figure 5b is a plan view of the same tray; Figure 5c is a plan view of a modified tray; and Figure 6 is a side view of a de-skinning plant embodying the present invention, which includes the de-skinning apparatus and additional equipment for loading products into it.

The overall construction of the de-skinning apparatus 2 is best seen in Figure 1.

Within a horizontally elongate sheet-metal conveyor housing 4 is an endless loop conveyor, and selected front panels of the housing are removed in the drawing so that the conveyer can be seen at 6. Components of the conveyor's drive mechanism are enclosed within a guard housing 8.

Above the conveyor is a generally cuboidal processor housing 10 formed by tubular metal vertices such as 12 supporting transparent panels such as 14, through which processing can be observed by an operator. Skin removal is carried out within the processor housing 10 by means of water jets, as will be explained below. Beneath the conveyor is provided a collection tray or sump 16 in which water is collected, and a drain pipe 18 passes the water to a filter unit 20 by means of which contaminants, including the skins, are removed before the water is passed via a reservoir 22 to a pump unit (not illustrated) and so re-circulated and re-used in the deskinning apparatus. A chosen proportion of the water, typically 5 percent, is not re-circulated but instead is bled to a drain. Mains water is added to maintain the water level. In this way the water is renewed and microbial contaminants are kept to an acceptable level. A tubular metal leg structure 24 raises the de-skinning apparatus high enough to allow the contaminated water to be gravity fed to the filter unit 20.

In Figure 2 the interior of the processor housing 10 is depicted. Receptacle trays 26 carried by the conveyor 6 are seen to be arranged in rows of three, each row being supported upon a bogey whose wheels are indicated at 28. A shaped depression 30 in the upper face of each tray 26 serves as a receptacle for the products to be skinned. The shape of the receptacle will be described in detail below. Collectively the trays 26 upon the conveyor form a square matrix of product receptacles, and above the trays is a corresponding matrix of enclosures 32. In the present embodiment the enclosures are each formed by a metal cylinder. Twelve such enclosures are arranged in four rows, although of course the number could be increased or reduced. A square carrier frame 34 formed of tubular metal is traversed by four rectangular carrier plates 36 and the enclosures 32 are bolted to the undersides of the carrier plates. The carrier frame 34, along with the enclosures and other components it supports, are able to be moved up and down relative to the trays 26. In the present embodiment this is achieved by mounting the carrier frame 34 through pneumatic actuators 38, 40 at opposite ends of the frame.

Each actuator comprises a respective ram body 42 defined within which are three cylinders receiving respective vertical rods 44, 46, 48. The two outer rods 44, 48 serve as guides only, but the middle rod 46 is coupled to a double-acting piston (not seen) within the ram body 42. The rods 44, 46, 48 are both rigidly coupled to the carrier frame 34 through a respective mounting plate 50 to which they are screwed and which is bolted to the frame. The ram bodies 42 are themselves mounted on respective pairs of vertical support arms 52,54 leading to a roof section of the processor housing 10.

Supply of water to each of the enclosures 32 is provided for by means of a common overhead manifold 56 from which lead flexible hoses 58 each leading to a respective swivel 60 passing through one of the carrier plates 36 and secured to it by means of a nut received upon the swivel's exterior, so that each swivel is co-axial with a respective enclosure 32. Turning now to Figure 3, the swivel also projects downward into the enclosure 32, beneath its support plate 36, and carries a rotary spray head comprising two "L" shaped tubular limbs 62, 64 each having a radial portion 66, extending from a hub 68 rotatably mounted by the swivel, and a downwardly turned outer portion 70. The swivel is of a commercially available type and provides for passage of fluid from the associated hose 58 to the tubular limbs 62, 64. Each of these limbs terminates in a downwardly directed nozzle 72, 74 through which a jet of water is provided in operation. Note that the water jets are not parallel to the rotational axis of the rotary spray head, but are inclined to it in such a way as to cause the spray head to rotate. Figure 4 shows how the nozzles 72, 74 are inclined, at 10 degrees in the present embodiment, although other angles may prove suitable, to the axis 76 of the swivel. As a result a component of the reaction forces on the spray head due to expulsion of the twin jets of water is along the circumferential direction and causes the spray head to rotate at high speed.

The rotary spray head additionally comprises a circular cover plate 78 which rotates along with the head and has only a small clearance with the surrounding enclosure wall. The nozzles 72, 74 emerge downwardly through the cover plate 78, but project only a small distance beneath it.

Around the lower edge of each enclosure 32 is an annular seal 80 formed of elastomer, and specifically of rubber in the present embodiment. However above the seal, the enclosure 32 is penetrated by numerous through-going holes 81 arranged in a rmg. v

The receptacle trays 26 are the same as those depicted and described in the above mentioned US Patent 6634283B2 and so will only be briefly described herein. For further details, please refer to the earlier patent. The trays shown in Figures 5a and 5b are in the present embodiment formed of moulded plastics. The receptacle 30 in each tray 26 may be described as substantially semi-toroidal, being circular in plan with an upstanding central boss 82 surrounded by the circular receptacle itself. The receptacle's surface is upwardly concave, when viewed in a sectional plane containing the receptacle's axis of symmetry. The base is shaped to provide raised ridges 86 which radiate from the axis but are curved so that their central regions are circumferentially offset from their ends. Between each such ridge is formed a respective channel 88. The base of the receptacle also has a set of radial through-going slots 90 through which fluid and also skins can escape. The formation of the receptacle promotes circulation of the products during their processing, helping to ensure that a high percentage of skins are removed. Figure 5c shows a modified form of the tray in which the slots 90 are replaced by circular openings 91.

Turning now to Figure 6, the plant illustrated therein includes not only the de- skinning apparatus 2 but also a bulk handling and loading assembly. The components of this assembly are known and commercially available, for which reason it will only be briefly described. A hopper 100 receives products such as nuts. Sacks of the products may be manually discharged into the hopper, but more preferably a bulk container is suspended from a hanging frame 102 above it. The hopper has a skirted adjustable r outlet gate through which the products are gravity fed at adjustable throughput rate onto a vibratory conveyor 104 leading to a bucket elevator 106, which in its turn raises the products above the level of the trays 26 and then discharges them into the trays. A controlled quantity is thereby provided to each tray.

The loaded trays 26 are advanced by the conveyor 6 of the de-skinning apparatus itself in a direction toward the right in Figure 6. Optical monitoring is used to ensure that in each operating cycle of the apparatus the conveyor is advanced sufficiently for it to introduce fresh trays and product beneath each enclosure 32 - in the present embodiment this requires that the conveyor is advanced four times the trays' length - and that when the conveyor halts a receptacle 30 is aligned beneath (and co-axially with) a corresponding enclosure 32. This is done while the enclosures and the carrier frame 34 are raised.

By application of suitable pneumatic pressure to the actuators 38,40, the enclosures 32 are then moved downwards such that their seals 80 come to rest against the region of the upper face of the respective trays lying around the receptacles 30.

It will be appreciated that in this condition each enclosure 32 forms with its adjacent receptacle 30 and its cover plate 36 a largely enclosed chamber, within which the process of skin loosening/removal takes place. This is advantageous in that it provides a positive means of confining the products during de-skinning, and so assists in minimising wastage. It is also beneficial in permitting creation of a fluid vortex acting upon the products. After lowering of the enclosures 32 into position, water is supplied r at high pressure. The pressure required has been empirically determined. In the illustrated machine pressures below approximately 6200kPa (900 psi) have been found to be suitable. For almonds 6030kPa (875 psi) is optional and for hazelnuts 3275kPa (475 psi). Water is passed through the manifold 56 and the hoses 58 to the nozzles 72, 74. The rotary spray heads eject high velocity fluid jets into the products beneath, and also rotate at high speed. Note that by virtue of the provision of the cover plates 78 the products are largely prevented from colliding with rotating components of the spray head. Such collisions would otherwise cause fragmentation and consequent wastage of the products. Only the projection of the nozzles 72, 74 beneath the cover plate 78 can collide with the products, which is why this projection is short. The rotating fluid jets create a powerful vortex within the product-containing chamber and this is found to be highly effective in removing the skins. The formation of the receptacles 30 promotes both skin removal and circulation of the products, to ensure all parts of their surfaces are uniformly treated. The products tumble up and over the ridges 86, assisting in their circulation. Water escapes through both the openings 91 in the receptacle trays and the holes 81 in the wall of the enclosure 32.

After a chosen interval the supply of water is suspended, the enclosures 32 and their carrier frame 34 are raised by the pneumatic actuators 38, 40 and the next operating cycle begins with the advancement of the conveyor. As the trays reach the end of the conveyor 6, they are inverted and their content is thereby discharged.

Claims

C- G CLAIMS

1. An apparatus for loosening or removing skin from particulate organic products, comprising parts for defining a set of chambers, each chamber having at least one associated nozzle for ejecting fluid into the chamber to effect skin removal, the parts defining each chamber being reconfigurable between an in-use configuration in which the chamber is substantially enclosed against egress of the products, although openings are provided for drainage of the fluid, and an open configuration in which access is available for loading of the products to be treated.

2. An apparatus as claimed in claim I wherein the parts for defining each chamber comprise an upwardly open receptacle for loading with a quantity of the products, and an enclosure, the parts being shaped to form when juxtaposed the substantially enclosed chamber, and at least one actuator being arranged to provide relative displacement of the receptacle and the enclosure between the in-use and loading configurations.

3. An apparatus as claimed in claim 2 wherein a conveyor is provided which serves to advance the receptacles from a product-loading region into a processing region in which skin removal takes place and then into an unloading region.

4. An apparatus as claimed in claim 3 wherein the enclosures are mounted on a movable carrier above the conveyor, the actuator serving to move the carrier downward to t juxtapose the enclosures with a set of receptacles beneath and subsequently to move the carrier upward to permit advancement of the conveyor.

5. An apparatus as claimed in any preceding claim wherein the nozzle(s) is (are) arranged to create a vortex within the chamber.

6. An apparatus as claimed in any preceding claim wherein the chamber is substantially cylindrical.

7. An apparatus as claimed in any preceding claim wherein a pair of nozzles are associated with each chamber and are arranged to spin about a common axis.

8. An apparatus as claimed in claim 7 wherein the nozzles are inclined to the axis to drive their spinning motion.

9. An apparatus as claimed in claim 7 or claim 8 wherein fluid conduits leading to the nozzles are separated from the interior of the chamber by a partition through which the nozzles project, the partition being arranged to rotate along with the nozzles, so that collision of the conduits with the products within the chamber is prevented.

10. An apparatus as claimed in claim 2 or in any subsequent claim dependent on claim 2, wherein each nozzle has a common mounting with its associated enclosure and so is located relative thereto.

ll. An apparatus as claimed in claim 10 wherein each enclosure comprises a downwardly open circular body into which the nozzle(s) project(s).

12. An apparatus as claimed in claim 11 wherein each enclosure comprises a set of radial, through-going openings for drainage of fluid from the chamber.

13. An apparatus as claimed in any preceding claim wherein all of the nozzles are connected to a common fluid supply manifold.

l 4. An apparatus as claimed in claim 2 or in any subsequent claim dependent on claim 2, wherein an elastomeric seal is provided between an enclosure and a receptacle.

15. A method of loosening or removing the skins of particulate organic products, comprising loading quantities of the products into multiple chambers each of which is substantially enclosed against egress of the products although it has openings for drainage of fluid, ejecting fluid from respective nozzles associated with each chamber onto the products within the chamber to effect skin removal, and subsequently unloading the products from the chambers.

16 An apparatus for loosening or removing skin from particulate organic products, substantially as herein described with reference to, and as illustrated in, the accompanying drawings.

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