FR2787289A1 - PROTECTIVE AND COVERING COVERING FILM FOR AGRICULTURAL CROPS AND METHOD OF MANUFACTURING AND LAYING - Google Patents

Abstract

Covering film of the plastic type based on polyethylene comprises at least one and preferably two pipes parallel and longitudinal with respect to its central part (1a) of the area of overlap of the cultivated part, these pipes (1b, 1c) receiving a ballast in fluid form of the water type, the said tarpaulin film being characterized in that at least one of the pipes internally receives a sheath (2) forming an expandable tube of great length established over the entire length of the said pipe or pipes overflowing of these, said sheath, having at its ends means (2a) for closing and closing to allow, after filling, the storage of one or more volumes of ballast water.

Description

-1

  PROTECTIVE AND COVERING COVERING FILM

  FOR AGRICULTURAL CULTURE AND METHOD OF MANUFACTURE AND

DEPOSIT

  The invention relates to the technical sector of the means used for the

  covering of cultivable land and established in the form of tarpaulins or films.

  We already know, to ensure the protection of cultivated areas and promote the growth of crops, the use of plastic films based on polyethylene. These films which constitute both a protection but also allow to create an environment favoring growth, are of a low cost price. These films are intended to remain permanently for a long period from the working of the soil with sowing until the harvest. They are therefore subject to constraints linked to a climatic environment, but they

  must remain in place for the entire period desired.

  Various tarpaulin films have thus been produced. It has been proposed for example in French patent 2,689,726 plastic films having at their longitudinal ends extruded pipes which can be obtained jointly by extrusion with the manufacture of the films or be attached and fixed in any suitable manner. These pipes have the function of allowing the insertion of a liquid or solid ballast. So, after laying the film manually on the area

  cultivated, the pipes are filled with ballast. FIG. 1 shows this embodiment.

  Considering this solution, it was found that it was impractical, resulting in many troublesome operations for the operator to insert the weights, regardless of the impractical aspect for harvesting the crops, and in particular asparagus which is one of the particular applications of this type of film. When the ballast is solid, for example earth, it is necessary that the operators introduce said earth

  in pipes in multiple places because projection is not possible.

  This consequently results in multiple operations taking into account the lengths of tarpaulin films (approximately 100 to 200 m depending on the case). This operation is therefore not profitable. In the case of liquid ballast, it is necessary that the film itself has a certain thickness to ensure solidity and avoid tearing of the walls of the pipes leading to the loss of the liquid. This tearing can either result from an apparent roughness on the ground, or when the film is staked. Films of this type are produced in a single operation with their central part for covering the earth and the side pipes for ballasting. This therefore means that the central part of the covering film is of the same thickness as at the location of the side pipes, and it is necessary to have a section of sufficient thickness for holding the ballast. Under these conditions, the covering films thus proposed have the drawback of not easily allowing the diffusion of ultraviolet radiation due to their too great thickness in the central part, but which results from the constraint of a thickness sufficient for the pipes. A bachage film thus described in the

  Patent FR 2 689 726 therefore has substantial drawbacks.

  Other solutions have been sought and in particular by the applicant who has proposed, in French patent No. 2,722,945, (FIG. 2) a particular tarpaulin film whose ends disposed beyond the pipes are arranged to be buried at the soil directly during the mechanical laying of the film on the crops to be protected. In this embodiment, the film has pipes laterally with external lateral extension strips intended to be buried on the ground. Wires or twines are introduced into said pipes and their ends come out of said film to be fixed to lashing stakes. This solution, although advantageous, is exploited by the applicant. However, it involves higher production costs in the manufacture and in the positioning of the film in the desired location. Also known from French patent 2,544,960 is a plastic sheeting covering laterally pipes filled with fluids, water, and having a plurality of nipples allowing fixing. We have

  shown in Figure 3 this embodiment.

  In this case also, the covering film is made in one piece from a single material, so that the thickness constraint necessary for the ballasting zones results in a limitation of the performance of the central part of the film as regards

passage of ultraviolet rays.

  With regard to the prior art thus considered, the applicant's approach was to find out how to optimize the design of a tarpaulin film ensuring on the one hand the protection of the cultivated area and allowing the best diffusion of ultraviolet radiation to through the film, and on the other hand, a ballasting of the covering film under very strict ground maintenance conditions, and ensuring the

  filling ballast areas very quickly.

  Another aim sought after according to the invention was to ensure the manufacture of a covering film with a low production cost while responding to the different

  constraints mentioned above.

  After much research, the applicant has imagined a new concept for manufacturing and installing covering film which responds very satisfactorily.

to different constraints.

  According to a first characteristic, the covering film of the plastic type based on polyethylene comprises at least one and preferably two pipes parallel and longitudinal with respect to its central part of the area of overlap of the cultivated part, these pipes receiving a ballasting in fluid form of the water type, said covering film being remarkable in that at least one of the pipes internally receives a sheath forming an expandable flange and of great length established over the entire length of the said pipe or pipes extending beyond them, said sheath , having at its ends closing and closing means for authorizing, after filling, the storage of one or

  several volumes of ballast water.

  According to another characteristic, the ends of the sheath (s) have ligatures produced directly from the end portions of the sheath for

form knot.

  According to another characteristic, the covering film comprising its central covering part and its lateral pipes is made of a thin plastic material, while the ballast sheaths are made of the same

  plastic but thicker.

  According to another characteristic, the process for manufacturing and covering the covering film is remarkable in that it implements the following operating phases: 25. Continuous and simultaneous production of the central part of the film and of its lateral, longitudinal pipes, with manufacture and introduction of the sheath (s) in the said pipe (s), * Laying of the covering film on the area to be covered, * Pre-closing of one of the ends of the sheath (s), * Projection of 'a fluid under pressure in water using a water distribution equipment equipped with a nozzle inside the sheath (s) through the opening which remains free and filling the sheath (s),

  * After filling the sheath (s), closures at both ends.

  These characteristics and others will become clear from the rest of the

description.

  To fix the object of the invention illustrated in a nonlimiting manner in Figures 1 0 of the drawings o: - Figures 1, 2 and 3 illustrate examples of tarpaulin films according to the prior art.

  - Figure 4 is a view of a tarpaulin film according to the invention.

  - Figure 5 is a cross-sectional view of the covering film before installation.

  1 s - Figure 6 is a cross-sectional view of the covering film after installation.

  - Figures 7 and 8 illustrate the method of filling the ballast sheaths of the

tarpaulin film according to the invention.

  In order to make the object of the invention more concrete, it is now described with a

  non-limiting manner illustrated in the figures of the drawings.

  The covering film of the plastic type based on polyethylene is referenced as a whole by (1). It includes a central part (la), extending laterally and longitudinally by two pipes (lb, lc), made of the same material. The formation of said pipes is obtained in any known manner during the extrusion and manufacture of the film. If necessary, said pipes can be extended by strips (ld) which can be buried, or simply laid on the ground. The covering film thus produced has a thin section which can be of the order of, for example, from 10 to 100 microns and advantageously of the order of 50 microns. This covering film is great

  length (up to several hundred meters) to cover the cultivated land.

  The ends (the) of the pipe or pipes open out.

  According to the invention, the covering film thus described is capable of receiving in at least one of the pipes and preferably both, a sheath (2) of a plastic material capable of receiving the liquid ballast such as water to allow stowage film on the ground. The sheath (s) are established or arranged over the entire length of the pipes, if necessary extending beyond them. The sheath (s) are made of a plastic material of the polyethylene type for example, but in a section of thickness (e2) greater than that (el) of the film proper. By way of example, this thickness is of the order of 100 to 300 microns and advantageously of the order of 150 microns. This thickness can vary depending on the material used. This thickness ensures a certain rigidity and solidity

  i 5 of the sheath against unexpected drilling by the operator.

  The sheath (s) are initially established in the form of strips which are introduced during the manufacture of the sheeting film proper in the

  pipes (lb, lc). They are in the initially collapsed state.

  The covering film thus produced is placed on the ground on the area to be covered by any

appropriate means.

  The implementation of the liquid ballast is then carried out in the following manner. An operator pre-closes one end of each sheath without

sealing (Figure 7).

  One then proceeds to the successive or simultaneous filling of the sheath (s) using a water distribution equipment known in the trade. This material notably comprises a water spray nozzle which is introduced into the remaining opening of the sheath (s). The projected water gradually and completely fills the sheath which swells in expansion taking on the appearance of a rod. This sheath thus develops inside its receiving pipe. When the filling operation is finished, the operator withdraws the nozzle and proceeds to the closure, by ligature or other equivalent means, of the two ends of the sheath. One thus obtains a sheath in the form of a sausage closed at its ends and therefore

  watertight, like a sausage with casing and meat.

  The ballast is thus arranged over the entire length of the bachage film, matching the shapes of the ground. Said ballast sheaths are thus protected by the

  pipes. Thus, the advantages of the invention are numerous.

  The tarpaulin film is made of the same material but with i5 sections of variable thickness depending on the covering area to be cultivated and the ballasting areas, allowing, for the first, excellent diffusion of light radiation, and for the second, strength and rigidity. The ballast sheath, because of its thick section, is more difficult to pierce. This aspect is reinforced by the fact that the surrounding pipe part should also be pierced. We

  thus constitutes a double drilling barrier to have access to the fluid ballast.

  We also emphasize the speed of installation and filling of the ducts thanks to the projection of pressurized water which can be defined and regulated taking into account the sectional constraints of the duct. Note also the ease of manual or mechanical removal of the covering film after use, with

  the opening of the ends of the sheaths then allowing the water to rise.

  The tarpaulin film is produced continuously.

Claims (1)

  -1-, Covering film of the plastic type based on polyethylene comprises at least one and preferably two pipes parallel and longitudinal with respect to its central part (la) of the overlap area of the cultivated part, these pipes ( lb, lc) receiving a ballast in fluid form of the water type, the said covering film being characterized in that at least one of the pipes internally receives a sheath (2) forming a long expandable tube established over the entire length of the one or more said pipes overflowing from these, said sheath having at its ends means (2a) for closing and closing to allow, after filling, the storage of one or more ballast water volumes.   i 5 -2-, tarpaulin film according to claim 1 characterized in that the ends of the sheath (s) have ligatures made directly from their   end parts to form knots.   -3-, tarpaulin film according to claims 1 and 2 characterized in that the film   covering includes its central covering part and its side pipes is made of a thin plastic, while the sheaths of   the ballast are made of the same plastic material but of greater thickness.   -4- Method of manufacturing the covering film, and of laying it according to one   any of claims -1- to -3- characterized in that it implements the   following operating phases: Continuous and simultaneous manufacturing of the central part (la) of the film and its lateral pipes (lb, lc), longitudinal, with manufacturing and introduction of   the sheath (s) (2) in the said pipe (s).   * Laying of the covering film on the area to be covered.   * preclosing of one of the ends of the sheath (s), * Projection of a pressurized fluid in water using a water distribution equipment equipped with a nozzle inside the (s) sheaths by the opening remained free and filling of the said sheath (s),   * After filling the sheath (s), closing at both ends.