PROTECTION SCREEN FOR PRINT READERS

Abstract

The present invention relates to a protective screen for fruit crops, defining a roof sized to cover at least one plant (1) or part of a plant bearing one or more fruits (3) or fruit buds to be protected. The screen includes a receiving element for a support for suspending the screen. The screen is characterized in that it has a thermally reflective underside (40), preferably made of aluminum. The screen transfers the thermal energy escaping from the soil to the plant, thus preventing the formation of radiative frost on these parts. The invention also relates to a method for protecting fruit crops against radiative frost, particularly grapevines. Fig. 3

Description

Title of the invention: PROTECTIVE SCREEN AGAINST SPRING FROSTS technical field

[0001] The present invention relates to the field of devices for protecting fruit crops, and in particular grape buds against radiative frosts.

[0002] The invention relates in particular to a protective screen having at least one metallized, thermally reflective underside for reflecting infrared rays escaping from the ground during a radiative frost event, and thus redirecting them onto the herbaceous parts. Preferably, said screen also has a thermally absorbent upper surface, allowing the heat from the sun's radiation to accumulate beneath said screen. The invention also relates to improved fastening means for said protective screen and a method for protecting fruit crops using said screen. STATE OF THE ART

[0003] French patent FR 2 843 276 B1 in the name of the present applicant describes a protective screen against rainwater runoff falling on grape bunches at advanced stages of ripeness and close to harvest. This device, illustrated in Figures 1 and 2 of the present application, consists of a plate 4 in the general shape of a double-pitched roof 4a, 4b, provided substantially in the central part of the roof edge 5 with an opening 6 bordered by two sides 9 and extended by an access slot 7 running along said edge 5 to one of the roof edges.

[0004] The slot 7 allows a wood 2 from the base of the vine to be inserted up to the edge of said opening 6, so as to form above the fruit to be protected 3 a double-sloped inclined surface permanently fixed by pinching onto the wood 2. The sides 9 of the opening ensure good pinching of the wood and the fixing of the screen to the wood, i.e., to a vine branch inserted through said slot up to the edge of the opening. This screen is also designed with accordion folds 11, formed parallel to the edge 5 in the slope areas 4a, 4b furthest from the edge, and on opposite sides 12. These accordion fold areas allow the length of each slope to be adapted according to the space available between two pieces of wood as illustrated in [Fig. 1].

[0005] This screen effectively protects the grape bunches from rain, however it is not effective against radiative frost.

[0006] The present invention aims to provide a new protective screen to allow its use against radiative frosts, which particularly threaten vine buds in spring.

[0007] Radiative frost occurs on clear nights with calm winds, when the ground loses heat accumulated during the day by emitting infrared radiation towards the sky. When the ground temperature drops below freezing, the moisture in the air begins to condense and freeze. Frost forms directly on objects close to the ground, such as plants, grass, fruit crops, etc.

[0008] Radiative frost also generates an inversion of air layers, naturally following an air temperature gradient that decreases with altitude. However, when the ground rapidly loses heat and generates radiative frost, a layer of colder air forms at ground level, followed by a layer of warmer air approximately 2 meters above the ground. One mechanical solution for protecting fruit crops from radiative frost involves using turbines to mix the air layers, thereby increasing the air temperature at ground level. This solution is, of course, very difficult to implement, as it requires installing numerous turbines to protect an entire field. In France, some vineyards use helicopters as air turbines, efficiently circulating the air over an entire plot. Naturally, this solution is not accessible to most winegrowers and farmers.

[0009] The present invention therefore aims to provide a new solution for protecting fruit crops, and in particular vine buds, against radiative frost. Description of the invention

[0010] The present invention provides a protective screen and a method for protecting fruit crops against spring radiative frosts. The invention relates in particular to the protection of grapevines, but can be used to protect other plants, and in particular other fruit crops such as kiwi, peach, apricot, etc. More specifically, the invention provides a protective screen defining a roof having a thermally reflective underside to reflect infrared rays escaping from the ground. This protective screen redirects the thermal energy escaping from the ground so that it is absorbed by the plant it protects and creates a microclimate of increased temperature beneath the protective screen.

[0011] More particularly, the invention relates to a protective screen for fruit crops defining a roof sized to cover at least one plant or part of a plant bearing one or more fruits or fruit buds to be protected, said screen comprising a receiving element for a support to suspend said screen, characterized in e that:

[0012] -said screen comprises a thermally reflective underside, preferably made of aluminium.

[0013] In particular, the lower face made of thermally reflective material is defined by a layer of metallized thermally reflective film comprising a silver face and a gold face, and in which

[0014] - said silver face is disposed towards an external and lower side of the screen intended to face the ground to reflect infrared radiation from the ground, and

[0015] -said golden face is disposed towards an upper part of the screen, and so as to absorb the heat from solar radiation.

[0016] In a preferred embodiment, said screen consists of a plate, and the screen further comprises a fixing support having a vertical rod connected on one side to said plate, preferably in a detachable manner and intended to be connected on the other side to a fixing means for a piece of wood of said plant, and said support is configured to hold the plate a few centimeters from the wood fixed by said fixing means, preferably less than 15 centimeters or less than 10 centimeters.

[0017] Advantageously, said means of fastening to the wood of the plant is a spring clamp, and said support rod has a snap-fit ​​connector that engages with one of the arms of said clamp. This support allows for easy and quick installation of the screen.

[0018] According to one embodiment, the plate incorporates an opening as a support receiving element, and the vertical rod of the support is provided with a crossbar to support said screen, and such that the support is connected to said screen by inserting an upper part of the rod of the support through said opening, and up to the buttock with the crossbar.

[0019] In other embodiments, the plate incorporates a snap-on, screw-on or push-fit fitting as a receiving element for the support rod.

[0020] When the plate incorporates an opening as a support receiving element, said opening may be extended by a slot extending to an edge of the plate, and the vertical rod may incorporate at least two crossbars. The screen will thus be fixed to the support by sliding the vertical rod at a height between the two crossbars through said slot, and up to the edge of the opening. This method of fixing between two crossbars provides greater stability to the screen. Alternatively, said slot allows the screen to be fixed directly to the wood of the plant without the use of the support.

[0021] In one embodiment, said vertical rod has a flat shape, and the opening has a substantially elongated shape and has a neck constricting said opening to an intermediate part of said opening.

[0022] In one embodiment, the plate is parallelepiped in shape and has accordion folds on opposite sides of the plate, said folds allowing the weight and / or length of said sides to be modulated.

[0023] In particular, the lower face of the screen made of thermally reflective material is defined by a layer of thermally reflective film chosen from a survival blanket film or a thermally reflective insulating film, and preferably fixed with an intermediate layer of air, continuous or discontinuous.

[0024] Finally, the invention relates generally to a method for protecting fruit crops against radiative frost, said method being characterized in that it comprises a step of protecting a plant with a protective screen having an underside made of thermally reflective material configured and installed to reflect infrared radiation emanating from the ground towards said plant. Preferably, the protective screen is made as described above and is fixed to the plant in close proximity to one or more fruits or buds to be protected, and in particular at a distance of less than 15 centimeters, preferably at approximately 10 cm or 5 cm. Alternatively, said screen is dimensioned as a roof covering one or more plants and said screen is installed by means of one or more supports on the ground. BRIEF DESCRIPTION OF THE FIGURES

[0025] Other advantages, purposes and particular features of the present invention will become apparent from the following non-limiting description of at least one particular embodiment of the devices and methods of the present invention, with reference to the accompanying drawings, in which: • Fig. 1 illustrates the installation of a protective screen on the wood of a grapevine according to the state of the art. • Figure 2 illustrates the design detail of the protective screen in Figure 1. according to the state of the art. • Figure 3 illustrates an example of the installation of a protective screen the invention according to an embodiment of the invention. • Figure 4 illustrates an example of a support for installing the screen. protector of the invention according to the embodiment of [Fig.3]. • Figure 5 illustrates a second embodiment of a mounting bracket of the protective screen of the invention. • Figure 6 illustrates one embodiment of the protective screen the invention optimized for its attachment by means of the support shown in figures 4 and 5. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention proposes a new solution for protecting fruit crops against radiative frost. In particular, the invention proposes protecting a plant by means of a protective screen having an underside made of thermally reflective material. The screen will allow the transfer of thermal energy escaping from the soil to the plant, and thus preventing the formation of radiative frost on these parts.

[0027] Furthermore, the screen will form a roof that also limits condensation of ambient air on the plant, thereby limiting the condensation layer that could create a layer of frost. Depending on the means used to install this screen, it can be sized to cover at least one plant or several plants. The screen can be made of flexible, semi-flexible, or rigid material, and may or may not be waterproof.

[0028] In a preferred embodiment of the invention, the screen is designed to allow its installation with a reduced investment. As seen in [Fig. 3], in this embodiment the protective screen consists of a plate 4 configured as a roof sized to cover in a relatively individual manner one or more fruits 3 or buds of a vine 1, said plate having a thermally reflective underside 40, preferably made of aluminum.

[0029] The lower face 40 of the plate 4 will have the effect of reflecting the infrared rays escaping from the ground 13, and redirecting them towards the fruits 3 or buds that it protects, as well as the parts of the plant and the atmosphere below said roof.

[0030] The protective screen will be fixed near the fruits 3 and buds to be protected using a support 20 or a fastening means allowing the screen to be installed like a suspended roof without side walls. The screen will be sufficiently close to the parts of the plant to be protected to generate effective heat concentration in the covered area; for example, it will be fixed a few centimeters or tens of centimeters away. For the protection of vines, the screen will, for example, be rectangular with dimensions of approximately 40 to 50 cm in length and about 30 cm in width.

[0031] The screen may also have a top surface made of absorbent material, so that when the sun rises, the screen can absorb the heat and concentrate it in the area protected by said screen. In this embodiment, care will be taken to ensure a space of at least a few centimeters between said screen and the areas of the plant to be protected in order to avoid burning the latter.

[0032] Several embodiments of the protective screen are conceivable, particularly with regard to its shape and attachment. For example, the screen may be constructed as a gable roof, according to the shape and attachment characteristics described in French patent FR 2 843 286 B1, and described above with reference to Figures 1 and 2 of this patent application. The screen may also form a flat or semi-flat roof of parallelepiped, circular, or conical shape with a circular or polygonal base. The roof shape characteristics are not limiting.

[0033] Once again, the essential characteristic of the screen for protecting against radiative freezing is that said screen has a lower face 40 made of a thermally reflective material for infrared radiation. In a preferred embodiment, the screen is made of a material Rigid or semi-rigid and waterproof plastic, or waterproof cardboard, with an aluminum layer on its underside. Preferably, the screen has a continuous or discontinuous air gap between the main material of the screen plate and the aluminum layer.

[0034] In a preferred embodiment, the screen is coated on its underside with a polyethylene terephthalate film covered with an aluminum film, having a reflective silver side and an absorbent gold side; this film is, for example, a survival blanket film. The silver side of this film will, of course, be oriented downwards to define the lower, thermally reflective surface of the screen, and the gold side towards an upper part of the screen.

[0035] The silver face reflects infrared onto the buds and the wood bearing, and the buds and the wood bearing re-emit IR into the water vapor under the screen.

[0036] For its part, the gold face reflects only part of the atmospheric radiation received, because of its brightness it cools very little and lets most of the radiation pass through, thus generating a thermal accumulation under the screen.

[0037] This embodiment therefore allows:

[0038] - a reflection of up to 95% of infrared radiation by the silvered side of the film in the immediate environment of the herbaceous and woody parts which re-emit some of it;

[0039] -an absorption of atmospheric radiation by the golden surface with a low reflection, allowing thermal accumulation below the screen and its absorption for the buds or fruits protected by the screen.

[0040] Advantageously, it is thus possible to accumulate infrared radiation from the sky and the ground below the screen. Preferably, in this embodiment, the screen is made of transparent plastic material to allow solar radiation to pass through to the reflective thermal film.

[0041] The buds of grapevines and fruit trees have an adaptive capacity to withstand a temperature of -5°C, provided they have the 15 to 45 minutes necessary for the osmotic pressure to cause the water contained in their cells to migrate into the intercellular sap, thus preventing its crystallization. Cells dehydrated of their water will be more resistant to frost.

[0042] The screen of the invention makes it possible to gain this time at daybreak during the sudden and temporary drop in temperature. Indeed, the screen of the invention allows the accumulation of thermal infrared radiation on the protected fruits or buds. Without wishing to be bound by a specific mechanism of action, it would appear that the molecular vibrations induced by the infrared radiation in the cells of the herbaceous parts allow the cells to adapt quickly and resist frost. Furthermore, the screen protects against humidification from rain the previous day and therefore keeps the buds during the temperature drop at daybreak. As already mentioned, this screen is intended to be fixed near the parts of the plant to be protected. In a preferred embodiment illustrated in Figures 3 to 6, the invention proposes fixing the screen by means of a cross-shaped support 20 having a vertical, or ascending, stem 21 and at least one horizontal crossbar 22. An upper portion of this ascending stem 21 is intended to be inserted into an opening 6 in the screen until it abuts against said crossbar 22. The screen will thus be supported by the crossbar 22 in a horizontal plane.

[0043] In a preferred embodiment, said support is connected on one side to said screen in a detachable manner, and on the other side to a spring-loaded clip 14 for clamping a piece of wood 2 of the plant bearing the fruit 3 to be protected. Wood is understood to mean any stem, twig, or branch of the plant (woody or not) that allows the screen of the invention to be attached to said plant.

[0044] Several fastening methods can be considered by those skilled in the art for connecting said support 20 to the clamp 14, for example, nailing, welding, gluing, etc. [Fig. 4] shows a preferred embodiment of said support 20 incorporating a cross member 22 and a snap-fit ​​connector 23 with one of the arms of a spring-loaded clamp 14. This support 20 is made from a flat rod profiled to form said connector 23, the rising rod 21, and the cross member 22. [Fig. 5] illustrates a second embodiment of this support incorporating a second horizontal cross member 22-bis, slightly shorter than the first cross member 22. This support can be made of metal or thermoformed plastic. The clamp can also include a transverse lug 15 allowing the clamp 14 to bear against the wood.

[0045] The support is notably designed to be connected to the screen by means of the upper part of the rising rod 21 intended to be received in a receiving element of the screen, in particular in the opening 6 of the screen. The rod 21 is inserted into this opening 6 and slid until it reaches the stop of the first cross member 22. In one embodiment of the plate 4, the central opening 6 is extended by an access slot 7 allowing said opening 6 to be inserted at different heights of the rising rod 21, for example between the two cross members 22, 22bis.

[0046] Figure 6 illustrates a preferred embodiment of the screen intended to be fixed with the fastening means illustrated in Figure 4 or 5. In particular, the central opening 6 has an elongated shape and a collar c that constricts said opening to an intermediate portion to grip the support rod. This elongated opening is particularly well-suited to facilitate the insertion of the flat support rod and to hold it in position without excessive play thanks to the collar. More specifically, the opening comprises a first, substantially circular opening 6a extended on one side by an access slot 7 and on the other side by a second circular opening 6b. of a larger diameter vis-à-vis a diameter of the first opening 6a. The central opening 6 and the slot 7 are provided with raised flanks 96, 97 allowing to reinforce said elements.

[0047] As illustrated in [Fig. 6], in this embodiment the plate also incorporates accordion folds 11 on opposite sides 12 of the plate. The accordion folds allow the length of the plate 4 to be modulated, and furthermore, generate an additional weight on each side of the plate, causing said sides of the plate to drop and slightly curve the latter when it is made of a semi-flexible material.

[0048] The invention thus provides a protective screen that can be easily installed and removed using simple means and at a low investment cost. Alternatively, the screen can be sized to cover one or more plants and be fixed by means of a support installed on the ground, which holds the screen above the plant or plants to be protected. The screen of the invention can also be made as a net-type frame incorporating a lower layer of reflective thermal film, and be positioned above a row of plants to be protected using supports on the ground.

Claims

Demands

1. Protective screen for fruit crops defining a roof dimensioned to cover at least one plant (1) or part of a plant bearing one or more fruits (3) or fruit buds to be protected, said screen comprising a receiving element for a support for suspending said screen, characterized in that: - said screen comprises a lower thermal reflective face (40) defined by a layer of metallized thermal reflective film, and comprising a silver face and a gold face, and in which - said silver face is disposed towards an external and lower side of the screen intended to face the ground to reflect infrared radiation from the ground, and - said gold face is disposed towards an upper part of the screen, and so as to absorb heat from solar radiation.

2. Protective screen according to claim 1, wherein said screen consists of a plate (4), and the screen further comprises a fixing support (20) having a vertical rod (21) connected on one side to said plate (4), preferably in a detachable manner and intended to be connected on the other side to a fixing means for a piece of wood (2) of said plant, and said support (20) is configured to hold the plate (4) a few centimeters from the wood (2) fixed by said fixing means, preferably less than 15 centimeters or less than 10 centimeters.

3. Protective screen according to claim 2, wherein said means of fixing to the wood of the plant is a spring clamp (14) and said rod (21) of the support has a fitting (23) to snap into one of the arms of said clamp (14).

4. Screen according to any one of claims 2 to 3, the plate (4) incorporates an opening (6) as a support receiving element, and the vertical rod (21) of the support is provided with a cross member (22) to support said screen, and said support (20) is connected to said screen by inserting an upper part of the rod of the support through said opening (6) and until it buttocks against the cross member (22).

5. A screen according to any one of claims 2 to 3, wherein the plate (4) has an opening (6) as a support receiving element, said opening (6) being extended by a slot (7) extending to one edge of the plate, and said vertical rod (21) incorporates at least two crossbars (22, 22-bis), and so that said screen is fixed to the support by sliding the vertical rod at a height between the two crossbars through said slot and up to the right of the opening.

6. Screen according to any one of claims 4 to 5, wherein said vertical rod (21) has a flat shape, and the opening (6) has a substantially elongated shape and has a collar (c) constricting said opening to an intermediate part of said opening.

7. Screen according to any one of the preceding claims, wherein the plate (4) is parallelepiped in shape and has accordion folds (12) on opposite sides of the plate (4), said folds (12) allowing the weight and / or length of said sides to be modulated.

8. Screen according to any one of the preceding claims, wherein the lower face (40) of thermally reflective material is defined by a layer of thermally reflective film selected from a survival blanket film or thermally reflective insulating film, and being preferably fixed with an intermediate layer of air, continuous or discontinuous.

9. Method for protecting fruit crops against radiative frost, said method being characterized in that it comprises a step of protecting a plant with a protective screen having an underside (40) of thermally reflective material configured and installed as a roof on at least one plant, or part of a plant and for reflecting infrared radiation emanating from the ground towards said plant, characterized in that said protective screen is a protective screen according to any one of claims 1 to 8, and which is fixed on said plant in the vicinity of one or more fruits (3) or buds to be protected.

10. Method according to claim 9, wherein said screen is dimensioned as a roof covering one or more plants and said screen is installed by means of one or more supports on the ground.

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