INTEGRAL USE OF SOLAR RADIATION FOR THE DEHYDRATION OF PLANT- AND ANIMAL-BASED FOODS

Abstract

The present invention is related with the treatment of vegetable and animal foods for its preservation and employment in the extraction of the active ingredients they include. More specifically it refers to the treatment of these foods with the comprehensive application of solar radiation. This comprehensive use of solar radiation in the dehydration of vegetable and animal foods is characterized fir consisting in a dehydration process that includes the following steps a) slicing of the dehydrating product into slices of 1 to 2 mm thick; b) expose the skin free surfaces of the product to the direct impact of sun beams; c) maintaining an air circulation, even if laminar in the premise to homogenize the humidity content in all of the air mass; ch) take the product to a humidity level of 5 to 10% d) pack the dehydrated product.

Claims

1. The comprehensive use of the solar radiation in the dehydration of vegetable and animal foods, characterized for consisting in a dehydration process that includes the following steps a) slicing of the dehydrating product into slices of 1 to 2 mm thick; b) immediately expose the skin free surfaces of the product to the direct impact of sun beams; c) maintaining an air circulation, even if laminar in the premise to homogenize the humidity content in all of the air mass; ch) take the product to a humidity level of 5 to 10% d) pack the dehydrated product.

2. The comprehensive use of the solar radiation in the dehydration of vegetable and animal foods, as described in the previous claim, characterized furthermore because the step b) is done during 5 to 7 hours.

3. The comprehensive use of the solar radiation in the dehydration of vegetable and animal foods, as described in claims 1 and 2, characterized because the exposure of the bare surfaces of the product is done alternatively.

4. The comprehensive use of the solar radiation in the dehydration of vegetable and animal foods, as described in claims 1 to 3, characterized furthermore because the air circulation is done by flowing the air to the interior of the premises where the dehydration is taking place.

5. The comprehensive use of the solar radiation in the dehydration of vegetable and animal foods, as described in claims 1 to 3, characterized furthermore because the air circulation is done by taking out the air of the premises and by natural displacement placing the air in as the result of such air exit.

6. The comprehensive use of the solar radiation in the dehydration of vegetable and animal foods, characterized because the installation used to develop this process includes a premise in which the dehydration will take place; within such premise there are slicing mediums placed for the dehydrating product that lead to supports where the sliced product receives the incidence of the solar beams and the humidity of the product is absorbed by the surrounding air and an air displacement medium in any position of the premise.

7. The comprehensive use of the solar radiation in the dehydration of vegetable and animal foods, as described in the previous claim, characterized furthermore because the premise is limited by a support wrapped in anti-aphid fabric.

8. The comprehensive use of the solar radiation in the dehydration of vegetable and animal foods, as described in the previous claim, characterized because such premise includes a support structure and an anti-aphid fabric with the shape of a semi-cylindric dome in the highest part of the premise.

9. The comprehensive use of the solar radiation in the dehydration of vegetable and animal foods, as described in the previous claim, characterized because such semi-cylindric dome extends from the highest part of the premise to the lowest part next to the ground.

10. The comprehensive use of the solar radiation in the dehydration of vegetable and animal foods, as described in claim 6, characterized furthermore because the support is selected amongst anti-aphid fabric trays or ant-aphid belts or conveyor belts.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0037] FIG. 1 shows the distribution of an equipment modality to dehydrate a food product by the means of the sun, in which the product is placed in a conveyor belt.

[0038] FIG. 2 illustrates another modality in which the product is placed in the fabric's frames.

[0039] FIG. 3 illustrates a modality with covered premises for the dehydration subject to the present innovation.

[0040] FIG. 4 shows another modality of covered premises.

INVENTION'S DETAILED DESCRIPTION

[0041] The present invention has two slopes, on the one hand it refers to a dehydration process by the means of solar radiation and on the other it refers to the installation that allows this dehydration in an efficient way, optimizing such radiation.

[0042] When we talk about the solar dehydration in most of the developments of the current state of the art, we generally speak of the transformation of radiation into heat energy. Generally, in these developments the absorption of the heat energy in solar radiation is optimized. There is a working fluid that absorbs such heat energy and subsequently this working fluid also heats the air which is in contact with the dehydrating product. Or the working fluid is directly the air that will be injected in the premises' space where the product's moist exit will be done, dehydrating it, and the absorption of such moist by the means of the surrounding air to drag it out the premises.

[0043] In this last case a solid surface is used as a receptor which will get heated with the solar radiation and subsequently releases the heat energy increasing the temperature in the working fluid.

[0044] In the present invention, both the process and the installation are designed so that besides from heat energy it's possible to take advantage of solar radiation to control the decomposition factors, as long as there are proper conditions on the humidity for these transformations.

[0045] Consequently, it's a fundamental requirement that the slicing of the product that is to be dehydrated is done as soon as possible before placing them in the band or in the trays where the product will be exposed to the impact of the solar radiation. To achieve this, one of the ways is that the slicing is done creating 1 to 2 mm wedges and immediately after its slicing the wedges will fall in the band or the trays.

[0046] Since in any dehydration it's necessary to drag the humidity from the product, avoiding for the surrounding air to reach a relative humidity of dew point, an installation requirement is that it allows the entrance and exit of air, without the need of turbulent flows, since a laminar flow is more than enough. Especially because the humidity absorption by the surrounding air is not in a very elevated rate. To achieve this, it's not necessary to place an extractor, that might be one of the modalities, it would be enough to place a fan that homogenize the air humidity throughout the space. It's proposed as a solution to cover the premises with an anti-aphid fabric, any other medium, such as glass or some sort of transparent plastic, will not cover the required conditions since some of the sun's radiations with certain frequencies will not pass that barrier.

[0047] Another fundamental aspect, mainly in the dehydration of product with a high humidity content, a volume and a product's formation with dimensions superior to 2 mm in at least one of its axis, is that it's necessary that one of the dehydration process steps is a reduction in at least one of its axis of such dimension, for which it's proposed a slicing of the product with wedges between 1 and 2 mm. And it's in this point when the critical situation is presented where it's required the action of the sun in the product to dehydrate, since the slicing exposes at least one surface, when the wedge was located in the edge of the product, and two when it's an in-between wedge. This exposure to the ambient, oxygen and other gases and microorganisms with the amount of humidity present in this surfaces, the water activity a.sub.w is pretty elevated and the presence of enzymes and biochemical products provokes that the enzyme and chemical reactions as well as the microbial growth become very intense under this conditions as long as a certain humidity is not achieved in the product 5 to 10%

[0048] Due to the above one of the steps covered by the present description is the impact of the solar radiation in the product's surfaces exposed to dehydrate for at least 5 to 7 hours before the product reaches de desired humidity.

[0049] To achieve this incident towards the product it's required that the premises are nor limited by plastic, glass or any other non-transparent material, since these materials would stop some radiation with certain frequencies. Therefore, it's proposed that the premises are limited by a support as wide as possible wrapped in an anti-aphid fabric, which will allow the entrance if not of all radiation, of most of it. On the other hand as a way of allowing the detach of the slices from the band or the trays, one of the modifications includes to place a susceptor beneath the bands or trays which allows a partial dehydration from the side of the wedge that is not in direct contact with the solar radiation and this allows for the surface of the wedge not to stick to the anti-aphid fabric.

[0050] As it may be foreseen, from a certain incidence angle from the sun over the anti-aphid fabric, the radiation will not be able to pass and impact on the dehydrating product. So, it's proposed in one of the modalities for the fabric to cover the premises with a fabric support that provides it with a semi-circular formation from the highest point to the part the premises are in touch with the ground.

[0051] Besides the formation of the fabric coverage that covers the premises, something that goes without saying is the location of the premises and its orientation. The premises must be placed in an elevated site where trees or any other surrounding construction would not create a shade. And must be oriented in such way that the sides with a greater surface are facing the sun throughout the year, this is, that in a rectangular premise one of the sides is facing east and the other west.

[0052] To increase the time of solar radiation incidence, two modalities are proposed, the first in which the product is as near as possible from the ground whether in a conveyor belt or in fixed trays. The displacement speed of the belt may be very slow, but the requirement to fulfill is that the product in its exposed side is in contact with the sun for 5 to 7 hours to allow dehydration without the spoiling effect from enzymes or microorganisms.

[0053] It should be sought, at least, that during the first dehydration hours the radiation impact on both exposed surfaces (skinless), when the product consists of slices. In the case of conveyor belts this might be achieved through overlapping in both ends of the belt, the one which is upstream with its edge in the superior part of the ending of the following belt.

[0054] In the tray drying modality, this might consist in two anti-aphid fabrics with its corresponding frames, being one of them slightly smaller so that it might fit in the other and maintains the product in-between the two trays, being able to turn them exposing the exposed surfaces of the sliced product alternatively to the solar radiation impact.

[0055] The mechanism will allow to keep up with the relative movement of the sun. In one even more sophisticated modality the union of the trays to its supports will consist on a ball joint that will allow two spins, one to follow the relative displacement of the sun during the day and the other to follow the sunrise and sunset during the seasons.

[0056] FIG. 1 shows the distribution of one equipment modality to dehydrate a food product by means of the sun, where the product is placed in a conveyor belt 1. This belt presents various modalities, one of which is continuous and the is formed by at least two segments in which the retail end of one matches, overlapping the initial edge of the following belt to allow the inversion of the exposed side of the product to the sun. It's important to mention that it's required to maintain a circulation, even if laminar of the air in the dehydration premises, with the objective of maintaining air with a homogenous humidity. In the preferred modality, in which the premises are limited by an anti-aphid fabric, it would not be needed the use of an extractor or air injector in the premises. A low capacity fan would be enough, to maintain a small breeze inside the drying premise.

[0057] It must be taken into consideration for the length of the belt and its speed that the incidence time required from solar beams in the product is of 5 to 7 hours or until the product reaches a humidity of 5 to 10%. During the drying is convenient to take into consideration that at least in the beginning its required for the sunlight to impact in both sides of the product's slice that is to be dehydrated. Which is why it's seek that in the first sections of the belt there are various steps that turn the side of the product that receives the solar radiation

[0058] In FIG. 1, the retail end 2 in the belt 1 overlaps with the initial edge 3 of the belt 4 to allow the slice turning 5. The distribution of the slices supports whether in trays or in belts is such that it must take greatest advantage of space, without allowing the free circulation of the operators. In any point the use of a fan is required to provide movement, even if laminar of the air. This aids the displacement of the natural convection of the air, displacement due to the hot masses of the inferior part which by diminishing its density with temperature moves up and displaces the masses of superior air downward since they have a higher density.

[0059] On the other hand, the superior mass has a lesser amount of water since it gives it up to the exterior air through the anti-aphid fabric. And when the sun shines the air has a relatively low humidity.

[0060] FIG. 2 shows another modality in which the product is placed in frames 20 with anti-aphid fabric 21. Having a preferred modality in which the frames are fixed in ptr's 22. Another modality has the characteristic in which the tray is fixed to a ball joint 23 that allows it with no engine to tilt the trays in order for the them to follow the relative displacement of the sun. It's also a preferred modality in which the tray is formed by two frames with the corresponding anti-aphid fabric, the frame 24 with dimensions so it might tightly enter the frame 20, in a telescopic way and that between both fabrics the product's slices are placed for dehydration, so that just by spinning the assemblage its possible to switch the sides facing the sun, without turning wedge by wedge.

[0061] FIG. 3 shows a modality in which the premises' cover for the dehydration subject of the present invention. This is a very simple construction and it only consists in a superior crossbar 30 with a pair of inclined poles 31 on each edge forming a triangle with the vertex above. All of this is enveloped by an anti-aphid fabric 32.

[0062] FIG. 4 shows another coverage modality for the premise. In this modality the support structure of anti-aphid fabric provides it with a semi-cylinder formation to achieve a better utilization of the solar radiation to allow throughout the relative route of the sun, the least shade over the dehydrating products. The curve on the semi-cylinder has a relation with the curve of the sun in the horizon so that the solar radiation penetrates tangentially the mesh or anti-aphid fabric 32 so that they generate a minimum shade.

[0063] This formation might be coupled with a tilt in the supports where the dehydrating product's slices are placed, and such slices will receive a maximum of solar radiation.

[0064] The invention has been sufficiently described in order for a person with average knowledge in the field to reproduce and obtain the mentioned results in the present invention. However, any skillful person in the technical field related to the present invention may be able to make undescribed modifications to the present application, but if, for the execution of those modifications in a determined structure or in its manufacturing process, it's required the matter requested in the following claims, then they should be comprehended within the scope of this invention.