DEVICE FOR THE CONTROL OF THE FLOW OF DRIPPING IRRIGATION

HOSES DESCRIPTION Technical Field

The present invention refers to a device for the control of the flow of dripping irrigation systems of the kind that comprises hoses provided with a series of openings oppotunatly spaced to assure a certain degree of dripping in determinated desired points of cultivation ground.

Description of the prior art

As known, the dripping irrigation systems are very widespread to irrigate cultivation fields, in particular in the areas characterized by long periods of drought.

The dripping irrigation plants comprise the use of hoses supplied with a predeterminate number of openings in correspondence to which are placed some devices opportunately conformed to obtain a temporal dosage of the liquid, usually water in which there can be dissolved fertilizing substances, to distribute in a localized manner on a cultivation surface.

In this way, it is obtained an almost uniform distribution of the irrigation liquid on the treated surface.

The most common flow control devices present a laminar shape and are placed in correspondence of the different openings longitudinally to the hoses. Each flow control device present, in particular, a face turned toward the irrigation liquid and a face against it facing toward the opening. The two faces are then in comunication through a passing hole, through which the irrigation liquid that passes the hoses is sent in a path, or labyrinth, obtained on the face of the control device turned towared the opening. The labyirinth presents such a geometry to produce a loss of pressure on the liquid that passes through it and finishes with an enlarged portion, or collection chamber, which is placed in correspondence to the opening and that works as a collection tank for the water that leaks drop by drop from the hole.

The liquid flow control devices can be fixed to the irrigation hose to which are designated different techniques. For example, the flow control devices can be fixed to the wall of the hose through heat seal during the extrusion of this last one.

Regardless of the assemblage technique used, it is necessary that the flow control devices are oriented correctively respect to the created, or in creation hose.

For this aim are used complex machineries supplied with optical devices that detect the spacial orientation of each control device. Moreover, only the pieces that are correctively oriented are sent to an introduction station, while those that have been wrongly oriented are discarded and collected in a collection station from which are then launched again to the plant upstream.

The control is made to verify the positioning of the device in the four possible directions front and rear - up and down. It is clear how the neccessaty of a correct disposition that satisfies these four conditions is extremely difficult to obtain and implies remarkable rejections and consequent time and production losses. In order to eliminate two of the four controls it is then expected to positionate the collection chamber almost in a central and simmetric position respect to the labirynth. In this manner, in the device it is not anymore distinguished a front and a rear but is it totally indifferent the direction of the introduction.

Despite that it is currently required to verify the positioning of the device from the up and down point of view. For this aim, to allow to make in an authomized manner the operation of determination of the orientation of the flow control devices, these are provided with a reference edge (for example a line), in correspondence to the face that turns toward the liquid flow that passes through the hose when is used. This allow to individuate if the flow control device has reached in correspondence of the above machineries for the determination of the overtuned spatial orientation, in which case is discharged, or rather from the correct side and therefore sent to the assemblage phase inside the hose. Despite the introduced improvements, it is still clear how these operations of detection of the spatial orientation of the flow control device often imply to long time losses, as each time that a control device gets in correspondence to the detection machineries oriented in the wrong manner, or rather overturned, it is necessary to wait until it is removed from the area and substituted with the next device. Morever, the above machinery for the detection of the spatial orientation are sophisticated and expensive and therefore their use implies unavoidable elevated production costs.

Another noteworthy inconvenient related to the presence of the added edge is related to the high rigidity that it confers to the same device, making it not much flexible. This implies a high risk of tearing of the hose when this is wind up to the bobbin with strip that are long more than two kilometers. In order to economize the spaces it is indeed necessary to wind up in a very tight manner the hoses around the bobbin. Being this generally very flexible and with low thickness (generally under half a millimiter) it is clear how it could easily tear up in the points where the device does not sustain the flexure. It is at this point clear the remarkable damage both economical and of image impact for the producing company. The tearing are hardly locatable during the wind up and this implies to put into commerce a damaged product which is not usable by the buyer.

At last, nowadays, the device in commerce are realized prevalently by injection molding with dimentions that are different from the flow rate of water desired to obtain. This implies each time the use of matrixes with different sizes in fuction to the flow rate, the whole increasing remarkably the production costs.

Disclosure of invention

Thus it is the aim of the present invention to give a flow control device for dripping irrigation hoses that allow to remarkably simplify the detection operation of the spatial orientation of the same. It is another aim of the present invention to give a so made flow control device that allows to avoid the use of sophisticated and expensive machineries to individuate the spatial orientation.

It is another aim of the present invention to give a so made flow control device that allows to increase the production speed respect to the prior art devices.

It is another aim of the present invention to give a so made flow control device that has an elevated flexibility to entirely eliminate the risks of tearing in the hose.

These and other aims are reached by a fluid flow control device of a drip type irrigation hose, the control device being placed in correspondence to an opening of the hose and having a first surface that, in use, is facing toward the opening and a second surface, opposed to the first surface that faces toward said flow, said first and said second surface being in communication through at least a passing hole through which the fluid that flows inside the hose is sent into a path, or labirinth, realized on the first surface and having such a geometry to cause a pressure fall of the fluid before it exits from the hose through the opening, which main feature is that the second surface presents a second path, or labirynth, in communication to the, or each, passing hole, said second path, or labirynth, having such a shape to cause a pressure fall of the fluid when the second surface is toward the opening and the first surface is toward the flow of the fluid. In particular, the presence of a path, or labirynth, also on the second surface of the flow control device allows to simplify the checking process of the correct spatial orientation of the same device in correspondence of an introduction station. Indeed, the checking is limited to the control of the orientation of only the longitudinal and transversal dimensions, while it is not necessary to check on which is the surface that faces towards the opening at the time of the introduction of the device for the flow control inside the hose. Advantageously, the path, or labirynth, presents an enlarged portion, or collection chamber, that in use is placed in correspondence to the opening of the hose.

Advantageously, at least one between the path realized on the first surface and the path realized on the second surface presents a geometry having a centre of symmetry. More in detail, the, or each path comprises a pattern having at least a first and a second portion, said at least a first and a second portion being symmetric respect to a centre of symmetry. Advantageously, the centre of symmetry is placed in correspondece to the enlarged portion, or collection chamber. In particular, the centre of symmetry can coincide to the centre of the collection chamber. Such a solution allows to streamline furthermore the preliminary control phase for the correct spatial orientation as it is not necessary to verify which one is the direction of the longitudinal and transversal dimentions . Advantageously, at least one between the path realized on the first surface and the path realized on the second surface gets extended from said, or each passing hole, to the enlarged portion.

According to another aspect of the invention, a drip irrigation hose comprises:

— a plurality of openings distributed longitudinally to said hose at predetermined intervals;

- A plurality of fluid flow control devices, each flow control device of said plurality comprising a first surface that in use is facing toward said opening and a second surface, opposed to said first surface, that faces toward said flow, said first and second surface being in communication trhough at least a passing hole through which, the fluid that flows inside said hose is sent to a path, or labirynth, realized on said first surface in a way to cause a pressure fall of the fluid before it exits the hose through said opening which main feature is that said second surface presents a second path, labyrinth, in communication to said, or each passing hole, said second path, or labirynth having such a shape to cause a pressure fall of the fluid when said second surface faces toward said opening and said first surface faces toward said flow.

According to another aspect of the invention, a method for the production of a flow adjustment device for a drip irrigation hose comprises the phases of:

- Disposal of an injection mold provided with a cavity capable to be filled up with pressure melted plastic material and comprising a surface turned toward said cavity and provided with a plurality of reentering portions and a plurality of projecting portions .

- Introduction of melted plastic material inside said injection mold;

- hardening of said melted plastic material inside said mold obtaining said flow adjustment device comprising a surface provided with a plurality of projecting portions in correspondence to said reentering portions of said surface of said mold and with a plurality of reentering portions in correspondence to said projecting portions of said surface of said mold, said reentering portions and said projecting portions defining a path, or labirynth, having such a shape to cause a pressure fall to a fluid that passes through said irrigation hose when said surface is turned toward an opening of said hose; said mold comprising a second surface that in use faces toward said surface, said second surface being provided with a second plurality of reentering portions and a second plurality of projecting portions, therefore said flow adjustment device obtained at the end of said hardening phase comprises a second surface opposed to said surface and provided with a second plurality of projecting portions in correspondence to said reentering portions of said second surface of said mold and with a second plurality of reentering portions in correspondence to said projecting portions of said second surface of said mold, said second reentering portions and said second projecting portions defining a second path, or labirynth, having such a shape to cause a pressure fall of a fluid that passes through said irrigation hose when said second surface is facing toward an opening of said hose.

In another version of the invention, a method for the production of a flow adjustment device for a drip irrigation hose comprises the phases of:

- Obtaining a strip in plastic material, said strip having a first surface and a second surface opposed to said first surface;

- molding on the first surface of a path, or labirynth, said path, or labirynth, being able to be placed in correspondence of an opening of the irrigation hose and having such a shape to cause a pressure fall to a fluid that passes through said hose when the first surface is facing toward the opening and the second surface is facing toward the flow; and being expected, also, a molding phase of said second surface, said molding phase of said second surface being able to realize a second path, or labirynth on said second surface, said second path, or labirynth having such a shape to cause a pressure fall to said fluid when said second surface is placed toward the opening of said hose and said first surface faces toward said flow.

In particular, the molding phase of the first surface and the molding phase of the second surface are realized contemporarely . Brief description of drawings

Further features and advantages of this device, according to the present invention, will be clearer with the description that follows of one of its pattern realization, made to illustrate but not limit, with reference to the annexed drawings, in which:

- figure 1 shows in a longitudinal sectional view a device, according to the invention, for the flow control for irrigation hoses of drip type in use; - figure 2 shows in a plan view, the flow control device of figure 1;

- figure 3 shows the flow control device of figure 2 in a prospective view from above;

- figure 4 shows the flow control device of figure 2 in a prospective view from below;

- figure 5 shows in a plan view a realization version of the flow control device of figure 2;

- figure 6 shows the flow control device of figure 5m according to the A-A arrows; - figure 7 shows the flow control device of figure 5, according to the B-B arrows;

- figure 8 shows the flow control device of figure 7 in a prospective view from above;

- figure 9 shows the flow control device of figure 7 in a prospective view from below;

- figure 10 shows in a longitudinal sectional view a flow control device of figure 7 applied to a dripping irrigation hose;

- figure 11 shows in a plan view the flow control device of figure 7 to highlight some geometric properties of the comrpised labirynth;

- figure 12 shows in a perspective transversal sectional view the flow control device of figure 7 applied to a dripping irrigation hose; - figure 13 and 14 show schematically in a plan view two different possible embodiments of use adaptable from the flow control device of figure 7;

- figure 15 shows in a plan view a further version of the flow control device of figure 1;

- figure 16 shows schematically in a longitudinal sectional view a molding usable to realized the flow control device of figure 7 through a phase of injection molding of plastic material; - figure 17 shows schematically a molding phase of the labirynth on the surfaces of the flow control device of figure 7 through heat-sealing technology.

Description of a preferred pattern realization

With reference to figure 1, a device 10 for the flow control 100 of a fluid that passes a dripping type irrigation hose presents a laminar shape and comprises a surface 1 that faces towards an opening 25 of the hose 20 and a surface 1' , opposed to the surface 1 that, in use, faces towards the fluid flow 100 that passes the hose 20. The surfaces 1 and 1' are put into comunication through a determinate number of passing holes 3 through which the fluid that passes inside the hose 20 passes from the surface 1' to the surface 1 and is sent in a path, or labirynth 2, realized on this last one. To facilitate the sending of the fluid into the labirynth 2, or 2', according as the surface faces towards the opening of both the surface 1, or the surface 1' , respectively, the portion of the device 10 surrounding the passing holes 3 is expected to be hollowed. In particular, the path, or labirynth 2 presents a particular geometry, for example zigzag, such to cause a pressure fall of the fluid 100 that passes it which thus arrives in correspondence of the opening 25 of the hose 20 with a reduced pressure respect to the initial pressure. This determinates the "drop by drop" exits of the fluid through the openings 25 of the hose 20. The path, or labirynth 2, in particular, presents an enlarged portion, or collection chamber 4, that in use is placed in correspondence ^' to the opening 25 of the hose 20. The fluid, once it passes the path 2, is collected in the collection chamber 4, and from here is sent off outside from the hose 20 through the opening 25. According to what is expected by the invention, also the surface 1' presents a path, or labirynth 2' , similar to te one realized on the surface 1 and provided with a respective enlarged portion 4 (figure 4).

This type of constructive solution allows to remarkably simplify the checking operation of the correct orientation of the device 10 for the flow control, that is limited to the orientation of the longitudinal and transversal dimentions.

In the solutions shown in the figures from 1 to 12, the labirynth, gets extended from the -passing holes 3 until the collection chamber 4.

In a pattern realization shown in the figures from 5 to 14 the path 2 of the surface 1 and the path 2' of the surface 1' present a geometry having a central symmetry. More in detail, as shown in figure 11 the drawing comrpises a first portion 11 and a second portion 12 symmetric respect to a centre of symmety C. In particular, t each point A, or B, of the portion 11 corresponds a point A' , or B' of the portion 12 placed at the same distance from it from the centre of symmetry C. A further symmetry is obtained also respect to the surface 1 and 1' (compare figure 8 and 9 and look at figure 3) . In particular there is a symmetry respect to a α longitudinal plane approximately parallel to the above mentioned two surfaces and such to separate the upper surface 1 from the lower one 1' . In this manner the two parts a perfectly symmetric and identical making this way totally indifferent the positioning from a side or from the overtuned side.

This allows, from one side to simplify furthermore the detection operation of the spatial orientation of the flow control device, and from the other to use the same control device in two different application embodiments. For such aim (look for example figure 13 or figure 8 and 9) the two portions 11 and 12, obtained in a symmetric manner respect to the surfaces 1 and 1' other than symmetrically respect to the enlarged portions 4, are provided with two series of independent holes 3. in particular a group of holes 3 is placed from the side of the labirynth 2a and 2a' and a group of holes 3 is placed from the side of the labirynth 2b, 2b' and both with the same flow rate (1 litre/hour for side). This implies, as better described later, that with a same mold is possible to realize plate with two different flow rates. Alternatively, in a first emobodiment shown in figure 13, the control device 10 can be assemblade to the hose 20 in a way to use only one of the portions 11 and 12 of the labirynth 2, for example the sole portion 11 obstructing the opposed opening 3. Alternatively, in a second embodiment, shown in figure 14, the control device 10 can be assembled to the hose 20 in a way to use both the portions 11 and 12 of the drawing. In particular, each portion 11 and 12 of the device is activated by opening the respective passing holes 3, while it is excluded by closing, for example through heatseal, the respective same holes 3.

As said, the first, or second, embodiment is particularly chosen in function to the flow rate of the fluid inside the hose. More precisely in case of mild flow rates (1 litre/hour) the flow control device 10 is used in the first embodiment, while in case of high flow rates (2 litres/hour) the flow control device 10 is used in the second embodiment.

In a further pattern realization, shown in figue 15, the surfaces 1 and 1' of the flow control device 10 present four portions 11-14, each of them provided with a labirynth 2a-2d. More in detail, two labirynth 2a and 2b are oriented along a first dimention and the other two labirynth 2c and 2d are oriented along a second dimention orthogonal to the first. The four labirynths 2a-2d merge together into a central collection chamber 4. This pattern realization allows to simplify furthermore the individuation phase of the orientation of the flow control device 10, making entirely dispensable the individuation of the transversal and longitudinal dimension. In such case, the flow control device 10 can advantageously have a square shape. In figure 16 it is schematically illustrated as an example a mold 150 usable to realize the flow control device 10, according to the invention, through an injection molding technology of plastic material, as for example melted HDPE. In particular the mold 150 is constituted by two halves 50 and 50' that in use are opposed to each other. Each half 50 and 50' of the mold 50 is provided with a respective surface 51 and 51' where each of them comprise a plurality of projecting portions to realize corresponding reentering portions of the flow control device 10 and reentering portions to realize corresponding projecting portions of the flow control device 10.

More precisely, the halves 50 and 50' of the mold 150 present on the respective surfaces 51 and 51' , that in use are facing each other, some projecting portions 52a, 52b e 52' a, 52' b reproducing "in negative" the drawings of the labirynth 2 and 2' to realize on the surfaces 1 and 1' of the device 10, projecting portions 54 and 54' to realize respective enlarged portions 4 and 4' other than projecting portions 53a, 53b e 53' a, 53'b that in use are place in contact to realize the passing holes 3 and 3' .

The introduction of pressured melted plastic material inside the mold 150 is realized through openings 55. Once the plastic material has reached a determinate hardening degree, the two halves 50 and 50' of the mold 150 are spaced for example through pullers of prior art, obtaining the device 10 comprising the two surfaces 1 and 1' where each is provided with a correspondent labirynth 2, or 2' .

In particular, the embodiment of figure 13 can be obtained by simply removing from the surfaces 51 and 51' of the mold 150 the projecting portions or insert 53b, 53'b obstructing thus the holes 3 from the portion's side 12.

A further possible version of the molding process of the labirynth 2 and 2' on the surfaces 1 and 1' of the flow control device 10, according to the invention, is shown in figure 17. In this case to realize the control device 10 it is used the thermoforming technology.

In particular, a strip 40 in plastic material, for example EPDM or HDPE, is pushed on a conveyance direction until it reaches in correspondence of a mold comprising a half 250 acting from the side of the surface 1 and a second half 250' acting from the side of the surface 1' to realize on the correspondent surface 1, or 1', a respective path 2 as described above.

It is at this point clear how all the aims of the present inventing have been reached. In particular it is clear how the realization of a labirynth on both the surfaces (in particular the embodiment specular respect tp the longitudinal plane) makes, the positiong on one side or on the overtuned side indefferent. Moreover are not anymore necessary the reference edges making this way the device extreamely more flexible and reducing remarkably the tearing off problem of the hoses.