Patent Description:
More specifically, the object of the invention relates to an absorbent filter which, shaped in the form of a cylindrical tube of plastic mesh, closed at both ends with two hermetic caps, incorporates therein granulated materials that absorb ethylene or other gases, and are applicable for the absorption of ethylene or other volatile substances produced by fresh products such as fruits, vegetables, flowers, or ornamental plants transported in refrigerated containers, thereby preventing them from spoiling too soon, which is essentially distinguished in that it has an innovative weaving of the thread of the mesh and a novel support which improve its aerodynamic properties, significantly increasing the air flow going through it, which results in a more efficient reduction of air contaminants, and in that it has a new design incorporating fewer plastic materials and allowing less waste to be generated.

The field of application of the present invention is comprised within the sector of the industry dedicated to gas filtration, specifically in the manufacture of filters for absorbing ethylene and/or other volatile substances produced by fruits, vegetables, flowers, and ornamental plants, and other fresh products. More specifically, the product is intended for the wholesale transport of said fresh products in any type of refrigerated containers.

As a reference to the state of the art, patent number <CIT>, which relates to an ethylene absorption filter for refrigerated spaces, should be mentioned.

The tubular filter that absorbs ethylene is widely used to protect fruits, vegetables, flowers, ornamental plants and other fresh products from the harmful effects of ethylene (ripening and senescence hormone) and other volatile compounds during transport. The tubular filter, filled with a granule that absorbs ethylene or other gases, is generally installed in the intake grating or upper part of the last pallets in the refrigerated containers by means of flanges which, in the case of the current Greenkeeper Iberia filter, are incorporated in the cap.

Right now, there are several companies on the market that sell different brands of said tubular filters on an international level (Greenkeeper Iberia SL, Bioconservacion SA, BioXTEND® Co, Ozeano Urdina SL and Sensitech Inc. ) which essentially do not differ from one another, so the product has become a type of market standard. In fact, four of these companies (including Greenkeeper Iberia) make the cylindrical tube with a semirigid inner mesh and a flexible outer mesh, having exactly the same specifications and with only the colour changing. The cylindrical tubular filter by Ozeano incorporates materials and specifications of another type in its support material, but it essentially does not differ from the others either in terms of functionality.

Fresh products given off ethylene at a constant emission ratio ranging between about <NUM> and <NUM>µl/kg*h under the usual temperature and atmosphere conditions in refrigerated containers. The ethylene produced by the fresh products themselves builds up inside the container. It has been demonstrated that there is a linear relationship between the ripening time and the logarithm of the environmental concentration of ethylene at a given temperature and that ethylene is active as a hormone at concentrations as low as <NUM> ppb [<NPL>; <NPL>].

Moreover, it has also been demonstrated that certain formed volatile compounds that are produced by fresh products (limonene, acetaldehyde, furaneol, ethyl-butonoate, etc.) act like gas signals that activate the germination and development of fungal spores [<NPL>; <NPL>].

For the ethylene or other gases not to build up to levels that are harmful for fresh products, the filtration system must absorb them at a greater ratio than the ratio at which they are emitted. The faster the absorption is, the lower the concentration of environmental contaminating gases is and the better the conservation of the fresh products will be.

A factor limiting the contaminant absorption speed and capacity of the standard tubular filter is the air flow going through it. Tubular filters are placed in the grating of the filter precisely to increase the air flow volume going through it. However, the air flow volume passing through the standard filter could still be very considerably increased. In fact, the objective of the present invention is to develop a new filter with better aerodynamic properties which significantly increase the passage of air through same.

Moreover, it must be taken into account that these tubular filters are for a single use and most of them end up in landfills if they cannot be recycled. In order to reduce the waste generated and to market a more environmentally friendly product, a second objective of the invention is to develop a new filter which incorporates a smaller amount of plastic elements in its design and can also be manufactured with biodegradable plastic materials.

<CIT>, <CIT> disclose tubular filters that absorbs ethylene or other gases for refrigerated transport containers.

The tubular filter that absorbs ethylene or other gases for transporting fresh products in refrigerated containers proposed by the invention is configured as an optimal solution to achieve the mentioned objectives, with the characterising details making it possible and distinguishing it being suitably described in the final claims attached to the present description.

More specifically, as mentioned above, the invention proposes a new type of filter, applicable for the absorption of ethylene or other volatile substances produced by fresh products such as fruits, vegetables, flowers, or ornamental plants transported in refrigerated containers, preventing them from spoiling too soon, said filter being formed as a cylindrical tube of plastic mesh, closed at both ends with two hermetic caps, incorporating therein granulated materials that absorb ethylene or other gases, and distinguished from those currently existing on the market basically by the following:.

Furthermore, it is also optionally distinguished by having a support which even further reinforces the amount of air passing through the inside of the tube, which, advantageously, incorporates a liquid collection system and is fixed in the container for successive uses.

Specifically, the filter is formed with a single biodegradable or non-biodegradable plastic mesh, with a thread weave the structural configuration of which, formed from an inner crown having the same measurements as conventional meshes, and an outer crown changing from a round shape to a wing shape, provides aerodynamic properties, since it facilitates the entry of air into the tube, generating a suction effect on the air which significantly improves the air flow going through it and which, therefore, more efficiently absorbs air contaminants and keeps them at lower levels for the benefit of the fresh products being transported. Optionally, there is also a support which is placed in the grating in a fixed manner and remaining in the container for successive uses, even further increasing air flow, and it furthermore incorporates an innovative liquid collection system to prevent staining the load due to the accidental leakage of liquid permanganate which may occur, albeit very rarely.

In one embodiment, the filter is in accordance with the conventional dimensions of <NUM>-<NUM> in diameter and <NUM>-<NUM> in length, and in an alternative embodiment, it has larger dimensions: <NUM>-<NUM> in diameter and <NUM>-<NUM> in length.

In turn, the reduction of plastic elements in the filter object of the invention is due to the following:.

The invention therefore provides the market with a new type of cylindrical tubular filters that absorb ethylene that are more effective and more environmentally friendly.

Table <NUM> inserted below includes the range of preferred dimensions of the tubular filter object of the invention and also of the standard model currently available on the market.

Air passage simulations were performed with said filter models using computer software (specifically, Ansys software), in standard filter EF100 (<NUM>) without the outer mesh which this standard model also incorporates (so the result is more favourable than it is in reality) and the filter object of the invention in its four formats:
i) EF100AS (outer diameter <NUM> and length <NUM>), ii) 2EF100 AS (outer diameter <NUM> and length <NUM>), iii) EF100AS+ and iv) 2EF100AS+, wherein it was observed that up to <NUM>% more air flow passes through the new filter formats than in standard filter EF100. In practice, this translates into a lower equilibrium concentration (of ethylene or other gases) inside the container and, therefore, less risk of the fresh products spoiling.

If a practical case of transport in a container is considered and simulation software which simulates the ethylene concentration inside the container taking into account the different variables (ethylene emission from the fresh product at the given atmospheric temperature and conditions, the total product mass, volume of the container, air flow through the filter, granule speed, etc.), it is possible to estimate the equilibrium concentration in the container (which is reached <NUM>-<NUM> hours after the container has been closed and depends on the emission ratio of the fresh products and on the absorption speed by the filter).

The graph in <FIG> represents a comparison of the equilibrium concentration estimated in a container with an ethylene emission of <NUM>µ/kg*h obtained with the different standard filter models and according to the invention. The vertical axis of the graph includes the amount of ethylene concentration (ppm), and the horizontal axis includes the time (hours). Specifically, the following filter models have been compared:.

In view of said graph, it can be seen that the filters object of the invention, and particularly model EF100AS+, that is, the one formed by two filters with an outer ∅ diameter of <NUM>, length of <NUM> and support, obtain clearly lower ethylene concentrations than the standard filters currently existing on the market do.

To complement the description that is being made and for the purpose of helping to better understand the features of the invention, a set of drawings is attached to the present specification as an integral part thereof, wherein the following is depicted in an illustrative and non-limiting manner:.

Finally, <FIG> shows the graph mentioned in the previous section which compares the estimated ethylene concentration in a container with an ethylene emission of <NUM>µ/kg*h obtained with different conventional filter models and filter models according to the invention.

In view of the mentioned figures and according to the numbering used, a preferred embodiment of the tubular filter of the invention, comprising that indicated and described in detail below, can be observed in said figures.

Therefore, as observed in said figures, the filter (<NUM>) in question is formed in a known manner by a cylindrical tube of plastic mesh (<NUM>), closed at both ends with respective hermetic caps (<NUM>), which internally incorporates granulated materials that absorb ethylene or other gases, and it is essentially distinguished by the fact that said mesh (<NUM>) has a structural configuration which facilitates the entry of air flow into the tube, being formed by the combination of an inner crown (<NUM>) formed by filament having a circular section (<NUM>) and an outer crown (<NUM>) formed by a filament which, instead of being circular, has a wing-shaped section configuration (<NUM>), wherein the circular base thereof is wider than the distal end thereof (<FIG>).

In the preferred embodiment, said tube of mesh (<NUM>), which is made of a plastic material as mentioned, being produced by a horizontal extrusion system rotating counter-clockwise and with air cooling, preferably has dimensions with an outer diameter (d) of between <NUM> and <NUM> and a length (l) of between <NUM> and <NUM>, wherein the circular filament (<NUM>) of the inner crown (<NUM>) preferably has conventional measurements, i.e., a radius (r) of <NUM>, whereas in the outer crown (<NUM>), the base of the wing-shaped filament (<NUM>) also has a radius (r) of <NUM>, the upper part has a radius (r) of <NUM>, and the distance (di) between the center of both is <NUM>, the total height (a) of said wing-shaped filament (<NUM>) being <NUM>, as shown in <FIG>.

The preferred material of the plastic mesh (<NUM>) is HDPE (high density polyethylene), combined or not combined with glass fibre, but there can also be another type of material. Optionally, however, it can also be manufactured from biodegradable materials biodegradable such as PLA (polylactic acid).

Optionally, the filter (<NUM>) comprises a support accessory (<NUM>) which is installed in a fixed manner on the grating of the container for which the filter (<NUM>) is intended, allowing for a successive use, since it can be readily incorporated in and removed from same, which considerably facilitates the operation of installing and changing the filter (<NUM>). In addition to serving as a support, this accessory also helps to increase air flow through the filter (<NUM>) even further due to its aerodynamic shape, and to prevent accidents due to staining the load by means of its liquid collection system.

To that end, as observed in <FIG> and <FIG>, said support accessory (<NUM>) consists of an elongate element made of plastic material which incorporates respective anchors (<NUM>) at the ends thereof suitable for being adapted to the different diameters and lengths of the filter (<NUM>), and between which there are provided two longitudinal parts, an upper longitudinal part (<NUM>) and a lower longitudinal part (<NUM>) between which the filter (<NUM>) is arranged, having an approximately planar configuration, causing them to function like 'wings' forcing the air to pass through the filter (<NUM>).

In the preferred embodiment, said anchors (<NUM>) are formed by respective C-shaped parts suitable for receiving the caps (<NUM>) of the ends of the tube of mesh (<NUM>) of the filter (<NUM>), providing an adjustable closure (<NUM>) which, by way of a flange that can be inserted into an eyelet (<NUM>), serves to secure the holding of same.

Furthermore, the inner face (<NUM>) of the longitudinal part or lower wing (<NUM>) defines a passageway serving to collect the liquid which may accidentally form in the filter (<NUM>), albeit very rarely.

Likewise, at least at one end of the support accessory (<NUM>) there is provided an opening (<NUM>) which communicates with said inner face (<NUM>) of the lower wing (<NUM>) and which, by means of inserting a hose (not depicted), can be connected to a collection vessel for said liquid (<FIG>).

In the preferred embodiment, the filtration means contained inside the tube of mesh (<NUM>) of the filter (<NUM>) consist of spherical granules or pellets formed from a natural, highly pure clayey base and potassium or sodium permanganate with or without active charcoal, although it can contain any type of granules.

Likewise, the filter (<NUM>) can have any of the weights and sizes within the usual range of tubular filters that absorb ethylene or other gases; however, the preferred size is <NUM> and the preferred outer diameter is <NUM> for containing <NUM> of granules, since this format can replace a currently more widespread practice of using <NUM> tubular filters measuring <NUM> meter and <NUM> of granules in the grating of the container, thereby reducing the amount of plastic material forming same and, accordingly, the waste generated once its service life has ended.

Claim 1:
A tubular filter that absorbs ethylene or other gases for refrigerated transport containers, formed by a cylindrical tube of plastic mesh (<NUM>), closed at both ends with respective hermetic caps (<NUM>), which internally incorporates granulated materials that absorb ethylene or other gases, characterised by the fact that said mesh (<NUM>) has a structural configuration which facilitates the entry of air flow into the tube, being formed by the combination of an inner crown (<NUM>) formed by a filament having a circular section (<NUM>), and an outer crown (<NUM>) formed by a filament having a wing-shaped section configuration (<NUM>), wherein the circular base thereof is wider than the distal end thereof, thereby facilitating the entry of air flow into the tube.