GB1596233A

GB1596233A - Integral drip irrigation system

Info

Publication number: GB1596233A
Application number: GB11750/78A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-03-23
Filing date: 1978-03-23
Publication date: 1981-08-19

Description

(54) IMPROVEMENTS IN INTEGRAL DRIP IRRIGATION SYSTEM (71) I, JAIME SAHAGUN BARRAGAN, a Mexican citizen, of 287 Calle del Teco, Zamora, Michoacan, Mexico, do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to a drip irrigation system and, more particularly, it relates to an integral drip irrigation system which, without the need of any auxiliary devices, contains integrally therein all the necessary elements for providing filtration, admission, flow control and pressure compensation and emission of the irrigation liquid in the appropriate places.

As is well known, a drip irrigation system is an irrigation system which has received great encouragement in the last years and for which the most accepted definition is that which states that it comprises the slow and frequent application of water or special irrigation liquids to the plants by means of mechanical devices called emitters. The above is generally effected in practice by means of the use of pipes, preferably plastics piping, which are laid along the plant rows or furrows and to which the emitters are applied in the desired places, said emitters having as their function to regulate the delivery of water to render it a slow one.

It must be point out that, the higher the number of plants existing in a row, the higher will be the number of emitters that must be coupled to the corresponding pipe and, consequently, the higher will also be the resulting cost, which occasionally reaches excessive levels such as in very dense crops, for instance, corn.

In view of the serious drawbacks shown by the prior art drip irrigation systems using individual emitters, the latter have been substantially abandoned and, in lieu thereof, special types of pipes have been designed for application in furrows, and wherein the conventional emitters are replaced by small bores or holes in the wall of the pipe, thereby avoiding the cost of the emitter itself, inasmuch as it is the wall of the pipe proper which acts as such an emitter, whereby a considerable economy is achieved which renders the practice of drip irrigation practicable for furrow crops.

At present there are several known type of special pipes, among which there may be mentioned the single wall pipe which comprises a common pipe having periodic series of minute bores through which the water flows outwardly of the pipe. Also very well known are the double wall pipes which comprise a two-wall pipe, having an inner wall and an outer wall, which inner wall contains said periodical series of minute perforations, whereas the outer wall comprises a number several times larger of perforations, in order to thusly appropriately distribute the water received from the bores in the inner wall and deliver it to the environment.

Still a third type of drip irrigation pipes that are very well known in the prior art for use in furrows crops, is described in U.S.

Patents 3,873,030, 3,870,236 and 3,896,999 which will be mentioned as references in more detail hereinbelow, and which disclose systems comprising irrigation pipes having adhered to their wall a pressure reducing element which comprises a winding passage which presents the advantage that it is clogged with considerable more difficulty than the prior art known pipes described above, inasmuch as the cross sectional area of the winding passages may be quite larger than is the case of the mere bores and inasmuch as suitable devices are provided to unclogg such passages if necessary.

Regardless of the above, it is a very well known condition that all the drip irrigation pipes know.n heretofore, including those described in the U.S. Patents mentioned above, get clogged very easily because of the introduction of solid matter contained in the water and none of them has been provided with an integrated filtration system to avoid such clogging, whereby it is always necessary to use these systems with very costly separate filtration units to remove the impurities contained in the vast majority of the waters and farming liquids, prior to their feeding to the drip irrigation pipes. Therefore, the clogging difficulties constitute the most difficult, costly and persistent problem that remains to be solved in drip irrigation systems.

One other serious problem of all the drip irriagation pipes of the prior art is the fact that in all of them the flow varies at the outlets or emitters in response to fluctuations in pressure caused by variations in the pressure of the source or in view of the mere topography of the land where said emitters are located.

On the other hand, such as is also well known in the art of installing drip irrigation systems, those systems which use long networks of pipes provided with dropers or individual emitters that have to be controlled also individually, have been abandoned in favour of the systems achieving flow reduction of the irrigation liquid by means of friction loses through elongated passages and more particularly through winding passages that are less difficultly controllable.

Even when there are many and diverse types of drip irrigation systems using the method of flow reduction of the irrigation liquid by means of friction loses or impacts against walls of winding passages, it must be pointed out that the two above described main problems have persisted up to the present date, and that said problems have not been solved by any one of the prior art drip irrigation systems, namely, the very important problem caused by variations in pressure that originate consequent variations in the flow of liquid at the outlets of the system, and the serious problem caused by the clogging of the chambers and winding passages by solid matter admitted into the system.

It is of course to be noted that, by means of the provision of winding passages to cause friction losses by changes in the direction of flow of the liquid that is being carried therethrough, the cross sectional area of said passages has been considerably increased, whereby the problem of clogging of the passages has been also considerably decreased but even when the clogging occurs with less frequency, the problem still persists in all the prior art irrigation systems.

Also, none of the prior art drip irrigation systems has been provided with pressure compensating devices, which causes the above mentioned problem of very considerable variations in the volume of irrigation liquid supplied by the emitter zones of the system, which in turn causes problems in the drip irrigation of certain crops with critical liquid requirements.

Among the very diverse drip irrigation systems built with winding passages that reduce the flow of the fluid by friction losses along the path of the irrigation fluid, it may be mentioned that in U.S. Patent 3,873,030 owned by the same applicant hereof, there is described and claimed a drip irrigation device that, using novel winding passages, is capable of reducing the pressure of the liquid coming from the irrigation pipe by the provision of a passage which mainly works through impacts and very frequent and sharp direction changes, thereby partially solving the problem of clogging, inasmuch as the passages can be made having a much larger cross sectional area, whereby the obstruction thereof is considerably reduced while not completely avoided.

U.S. patent 3,870,236, also owned by the same applicant hereof, describes and claims a modified drip irrigation device that operates under the same above described principles but that may be manufactured in the form of a continuous band or ribbon having passages periodically formed thereon, to each one of which corresponds a bore of the drip irrigation pipe and from each one of which said liquid is emitted through a slit or hole placed at the opposite end of the winding passage.

While the devices described and claimed in the above mentioned U.S. patents solved the problems of obstruction to a very important extent, the fact still remains that such drip irrigation devices do not contain an integrated filtration system, whereby the solid materials still can enter and flow through the admission zones of the winding passages and build up therein, whereby they may form serious obstructions. However, it must be pointed out that such obstructions occur with much less frequency than what could be expected from the devices working on friction loses and manufactured in accordance with the prior art. As this type of devices shown, described and illustrated in the above mentioned U.S. patents are normally integrally adhered to the pipe, when an obstruction occurs, it is relatively difficult to remove the same because, in order to achieve that goal, it will be necessary to disassemble the pipe and drip irrigation device, in order to remove the latter for the purpose of cleaning the same carefully before reutilization. In other words, in view of the fact that the pressure loss passage to which the drip irrigation liquid flows is integrally adhered to the wall of the pipe, it was generally impossible to unclogg the device, whereby when any obstruction occured, this greatly affected the performance of the system.

In U.S. Patent 3,896,999, also owned by the same applicant hereof, in order to remedy the drawbacks of the drip irrigation systems of the above described patents, a drip irrigation system was devised which incorporated the important aspects of having the winding passages manufactured by means of a highly flexible body of material, preferably coated with a flexible and resistant material, which enabled the user to collapse or squeeze the passage in any section thereof in order to loosen and release the possible obstructions that could have been possibly accumulated in the system.This improved drip irrigation device also introduced the feature of providing a check valve which was opened by the drip irrigation liquid which was being discharged and which was closed when such pressure ceased to be exerted, whereby entrance of any foreign material from the environment and into the system was also avoided.

Regardless of the fact that the drip irrigation system of U.S. Patent 3,896,999 described above solves many of the problems encountered with the drip irrigation devices prior to the advent of said invention, it must be pointed out that said device still does not solve the two essential problems that are up to now existant in all drip irrigation systems, namely, it nevertheless permits the entrance of foreign material entrained in the liquid into the passages, whereby the removal of such foreign material is required by means of squeezing or collapsing of the same, which represents a certainly difficult operation in most of the cases and is ocassionally also inefficient in view of the fact that the pipes are generally underground.Also, this system still does not solve the problem of regulating the volume of irrigation liquid emitted, when the pressure in the passages for such liquid varies in view of the pressure changes in the source of said liquid.

On the other hand, substantially all the prior art drip irrigation systems essentially relied on the provision of a winding passage member formed as a moulded solid body, either rigid or flexible, which manufacture was relatively costly and difficult and for which excessive amounts of plastics mouldable material were required, whereby said systems could not be considered as truly integrated drip irrigation systems, and could not be manufactured by means of simple lamination and moulding procedures, and still contain integrated filters to avoid the entrance of foreign matter to the winding passages and also for compensating variations in pressure of the irrigation liquid in order to avoid variations of the volumes of liquid discharge through the emitters, thus rendering said systems practically uncontrollable.

The only manner available to solve the above problems, particularly the two essential problems that still persist in all the prior art drip irrigation systems, was to combine said systems with independent and separate filtration systems that ensured that the irrigation liquid sent to the distribution networks was absolutely clean to avoid clogging of the passages, and also, by means of the provision of an automatic pressure control system for instance, using known pressure sensor valves, which increase, to a very considerable extent, the cost of installation of such irrigation systems, as well as the cost of maintenance and operation thereof.

According to the present invention there is provided an integral drip irrigation system comprising an elongated plastics laminate forming a conduit for carrying irrigation liquid, said laminate comprising a first flexible plastics sheet provided with a plurality of thermally formed cavities therein and a flat second flexible plastics sheet adhered to said first plastics sheet at the most prominent areas of the latter in order to define passages and chambers within said laminate by closing the open side of said cavities, said passages and chambers comprising at least one elongated winding passage extending along the laminate; at least one irrigation liquid admission passage for receiving said liquid and feeding it to one end of said at least one winding passage; at least one integral liquid emitter capable of receiving the irrigation liquid delivered through the opposite end of said at least one winding passage and discharging it outwardly of the laminate; an opening for discharge of irrigation liquid provided on one of the faces of the laminate at said at least one emitter; an integrated filtration system for filtering the irrigation liquid which comprises at least a thin slit for retaining solids, provided in said laminate at the side of the laminate opposite the side of the laminate containing said discharge opening and coincident with said at least one admission passage; and an integrated pressure compensating system comprising a non-supported area of said flat second sheet, spanning said at least one emitter, so that, when the pressure in the conduit increases, the non-supported area of said flat sheet acts as a compensating diaphragm which reduces the cross-sectional area of said emitter in proportion to any increase in the pressure within conduit.Some embodiments of the present invention will now be described, by way of examples, with reference to the accompanying drawings, in which: Figure 1 is a fragmentary and partially cut away plan view of a laminate which comprises an integral drip irrigation system in accordance with the preferred embodiment of the present invention, in which all the channels forming the system are suitably embossed in one of two sheets forming said laminate; Figure 2 is an elevational cross sectional view, taken along lines 2-2 of Figure 1 and looking in the direction of the arrows; Figure 3 is an elevational cross sectional view taken along lines 3-3 of Figure 1 and looking in the direction of the arrows; Figure 4 is a fragmentary elevational cross sectional view taken along lines 44 of Figure 1 and looking in the direction of the arrows;; Figure 5 is an elevational cross sectional detailed view, taken along lines 5-5 of Figure 1 and looking in the direction of the arrows; Figure 6 is a fragmentary cross sectional view taken along lines 66 of Figure 5 and looking in the direction of the arrows, to show the pressure compensating device of the irrigation system in accordance with the preferred embodiment of the present invention; Figure 7 is a view similar to Figure 6 but showing the action of the pressure compensating device when a pressure is exerted thereon and also showing its exit opening suitably cut out; Figure 8 is a fragmentary view of the central area of the laminate shown in Figure 1 but illustrating a collector channel built in accordance with a second embodiment of the present invention;; Figure 9 is a view of a drip irrigation system built in accordance with still another embodiment of the present invention, in the form of a continuous ribbon containing passages, embossed in the laminate by means of the blister method and adhered to an existing drip irrigation piping; Figure 10 is a fragmentary view, partially cut out to show inner details thereof, of an integral drip irrigation system built in accordance with still another embodiment of the present invention and comprising an independent laminate manufactured by the blister method, which may be converted into a flexible pipe with its drip irrigation passages integrally built therein, the same as in figure 1; Figure 11 is an elevational cross sectional view taken along lines 11-11 of Figure 10 and looking in the direction of the arrows;; Figure 12 is a perspective fragmentary view, partially cut out to show inner details thereof, of the discharge and pressure compensating element used in the system illustred in accordance with the embodiments of Figure 9 and 10; and Figure 13 is an elevational cross sectional view taken along lines 13-13 of Figure 12 and looking in the direction of the arrows.

Referring now to the drawings and more specifically to Figures 1 to 8 thereof, the integral drip irrigation system built in accordance with the preferred embodiment of the present invention, essentially comprises a laminate formed by a pair of elongated plastics sheets 1 and 2, with sheet 1 being flat throughout its body, whereas sheet 2 is suitably embossed or deformed in order to constitute winding channels that are generally indicated by means of the reference numeral 4, as well as a collector channel which is indicated generally by means of the reference numeral 5, said winding channels 4 being suitably distributed throughout the width and the length of the laminate and containing therein the pressure compensating devices which are at the discharge sections 6 thereof, while the said collector channel, which may be one or more channels depending on the design of the laminate, contains along the same the integral filtration system for irrigation liquid in accordance with the present invention, in order to avoid entrance of foreign matter to the channels 4 in conformity which what will be described in more detail hereinbelow and such as it can be clearly seen in Figure 1 of the drawings.

In the preferred embodiment of the present invention which is illustrated in Figures 1 to 8 of the drawings, the integral drip irrigation system comprises an admission or collector device 5 which has the form of a longitudinal channel defined by the bottom of the plastics sheet 2, the longitudinal embossed partitions 60 and 61, and the flat sheet 1 which closes the device, said collector 5 extending throughout the length of the laminate (and thus the pipe) as it can be clearly seen in Figure 1 of the drawings. While in this Figure there has been shown one single collector 5, anyone skilled in the art may be able to easily design different arrangements containing several collectors and different designs and arrangements of the channels 4 without thereby departing from the scope of the present invention as defined in the accompanying claims.

Collector 5, in accordance with the embodiment illustrated in Figure 1 of the drawings, is provided with a plurality of transverse partitions 51 which are originated at the inner walls of the longitudinal partitions 60 and 61, respectively, colinearly to each other throughout the length of the collector, in order to support the continuous slits 9 which are opened at the indicated positions through the flat sheet I covering the collector 5, such that the liquid running through the pipe which will be formed with the system illustrated in Figure 1 upon wrapping the same in the direction pointed by the curved arrows in Figures 2 and 3, or in the opposite direction, will pass through the thin slits 9, leaving the foreign solid matter out of the collector 5, inasmuch as said slit 9 exerts a very efficient filtrating action by virtue of its small width to thereby admit an irrigation liquid which is substantially free from solid matter into the collector 5 which will convey said liquid into the channels 4 which will be described hereinbelow.

In the above respect, it will be clearly apparent to anyone skilled in the art, that collector 5 may be built merely as a continuous channel without any transverse partition 51 such as it is illustrated in Figure 8 of the drawings and that in such instance the continuous slits 9 will be replaced by a plurality of intermittent slits 31, very thin and in any number, arrangement and shape, in order to constitute the filtration device of the system of the present invention, to avoid entrance of foreign solid matter into the collector 5.

As a very important aspect of the present invention, when the pipe is formed by wrapping the above described laminate over itself, it is preferred to leave collector 5 at the top of the circumference of the pipe in order to provide for the entrance of the water or irrigation liquid into said collector in a vertically upward stream, whereby all the foreign matter filtered by the slits 9 or the openings 31 will again fall down into the liquid body and will be entrained thereby without any tendency of the filtrating system 9 or 31 in accordance with the present invention to become clogged.This fully solves the problems confronted up to now in the practice of drip irrigation, namely, that the passages are frequently obstructed by virtue of the fact that entrance of solid foreign matter is allowed which, therefore, requires the provision of separate filtration systems at an elevated cost.

Collector 5 communicates with a plurality of winding channels 4 for reducing the pressure, and that may be distributed at each side of the collector as illustrated in Figure 1, but that may also be arranged in any length or in any number and that, in accordance with the merely illustrative embodiment of Figures 1 to 7 of the drawings, comprises channels 4 which first or forward stretch or length is defined at the other side of longitudinal partition 60 of collector 5, between said partition and an intermediate thinner partition indicated by means of the general reference number 57; the second or backward stretch or length of channel 4 is defined between said partition 57 and a longitudinal partition 59 which will be described in more detail hereinbelow; the third or forward stretch or length will be defined between said partition 59 and a new partition 57, whereas the last or backward stretch or length will be defined between said partition 57 and a partition 58 which will also be defined in more detail hereinbelow. Along the length of each channel 4 a series of transverse partitions 50 is arranged for covering only partially the width of the channel and alternately arranged on the side partitions so that they will be spaced and overlapped, thus forming a winding course or path for the irrigation liquid.

As at the other side of the partition 61 of collector 5 there are formed four channel stretches in accordance with the particular embodiment illustrated in Figure 1, defined between the several partitions 57 and the respective partitions 61, 62 and 58, respectively, the flow of the irrigation liquid through said channels, may be explained by having reference to only one of the two side portions, inasmuch as they are entirely mirror images of each other and it is not felt necessary to repeat the description thereof.

The stretches of the channels that correspond to each one of the integral emitters are defined between each pair of transverse partitions 52 and 53 along the laminate, such as is clearly illustrated in Figure 1 of the drawings and the flow of the irrigation liquid is effected from the collector 5 into the first stretch of channel 4 through a groove 63 provided at the longitudinal partition 60 or 61, to thereafter move forwardly to the opposite length of the forward first stretch and return through the backward second stretch, in order to pass to the forward third stretch through another groove 64 provided at the partition 59 or at the partition 62, as the case may be, and thence the operation is repeated so that the fluid will flow along the backward fourth or last stretch of the passage 4, to reach the emitter device 6, which comprises a chamber 71 formed between the last incomplete partition 50 and a complete partition 55 which is lower in its height than partitions 50, 58 and 57 for an objective that will be more clearly seen hereinbelow. The irrigation liquid, therefore, will pass between the upper edge of partition 55 and the inner face of the flat sheet 1 into chamber 72, and from there, also between the upper edge of a complete partition 54 of height equivalent to partition 55 and the flat sheet 1, into chamber 73 which contains the exit opening 65 which will be described with more detail hereinbelow.

As all the channels formed in the laminate of the present invention by the provision of an array of obstructing transverse partitions 50, perform in identical manner, it is not considered necessary to repeat the above description and the only matter that must be pointed out is that said channels 4 may adopt any shape, that is, they may be constituted by a single longitudinal length or they may be constituted by a plurality of forward and backward flow stretches and they may be arranged in any other form or disposition, provided that each channel be communicated with the collector 5 in order to receive irrigation liquid filtered by the filtration system 9 or 31 and in order to deliver said filtered liquid, upon reduction of its pressure through impacts and direction changes against the partitions 50, into the discharge chamber 73 of the emitter 6 to permit the liquid to flow out through opening 65 as has been clearly illustrated in Figures 1 to 7 of the drawings.

In Figure 5 the chamber 72 and its transverse partition 55 are clearly illustrated and it can be seen that, between the upper edge of partition 55 and the inner face of the flat sheet -1, there is a gap 70 which communicates chamber 72 with chamber 71 of each emitter device, in order to permit the liquid to pass through said gap 70 from one chamber to the other. Also, as illustrated in Figure 4 of the drawings, chamber 73 with its transverse partition 54 provide between the upper edge of the latter and the inner face of sheet 1 an upper gap 69 which communicates chamber 73 with chamber 72 for a purpose which must be more clearly apparent hereinbelow.The exit opening 65 is arranged at the bottom of chamber 73, said opening being normally covered by an integral plug 66 when the laminate is manufactured, said plug comprising, as it may be more clearly seen in Figure 6 of the drawings, a button 67 and a neck 68 which permits to cut out said button 67 by means of a knife or any other cutting device, in order to leave the exit opening 65 fully opened as illustrated in Figure 7 of the drawings.

The function of the pressure compensating device which is provided at the emitter 6 and is illustrated in Figure 6 and 7, is as follows. Having been reduced the pressure of the irrigation liquid by friction losses throughout the length of the corresponding winding passage 4, the pressure of said irrigation liquid at the emitter 6 is considerably lower than the pressure of the irrigation liquid that runs through the pipe formed by the laminate as explained above.Therefore, when the pressure in the pipe increases or decreases, the section of the flat sheet I which spans the chambers between partitions 50 and 53 acts as a diaphragm such that, when an excessive pressure P is applied as illustrated in Figure 7 of the drawings, sheet 1 will tend to close the gaps 69 and 70 of partitions 54 and 55, respectively, thereby reducing the cross-sectional area of the outlet and therefore constituting a very efficient pressure regulator that will avoid fluctuations in the volumes of irrigation liquid emitted through the emitters when the pressure in the interior of the pipe varies. With the above, another of the traditional problems presented by the prior art irrigation liquid systems, namely, the lack of the control of the flow caused by pressure variations, is completely solved.

Such as it may be clearly seen in Figures 2 and 3 of the accompanying drawings, partitions 58, 59, 60, 61 and 62 which define both the collector 5 and the channels 4, are formed by embossing the plastics sheet 2 in order to form trapezoidal grooves that will facilitate the wrapping of the laminate in the direction of the curved arrows illustrated in Figures 2 and 3, in order to form a pipe of approximate circular cross-section by means of the overlapping of the side flaps 3 of said laminate and the adhesion thereof by means of heat and pressure, such that, when said laminate is wrapped to form a pipe, the grooves 58, 59, 60, 61 and 62 will be arranged in a straight shape which will avoid undue strain in the finished pipe.Of course that it will be clearly apparent to any one skilled in the art, that the trapezoidal grooves described above may have the reverse shape as compared to that illustrated in the embodiments of Figures 2 and 3, that is, with their side walls diverging upwardly, in order to provide for the wrapping of the laminate in the direction opposite to that indicated by the curved arrows, such that the flat sheet 1 will be at the outer part and the embossed sheet 2 will be at the inner part of the wrapped pipe, in which case the device is modified such that the filtrating slits 9 or 31 will be provided at the bottom of sheet 2, whereas the emitter openings 65 will be provided in sheet 1.

It is to be pointed out that the provision of the laminate containing the integral drip irrigation system of the present invention wit the emitters having their outlets 65 covered by means of the plugs 66, presents considerable commercial advantages, inasmuch as the user merely needs to cut out the buttons 67 through the necks 68 of the outlets 65 that he may require, consistently with the disposition of the plants in the field or farm, which prevents the waste of water by being kept fully interrupted in all other places.

As clearly illustrated in Figure 9 of the drawings, both the integral drip irrigation system described above and illustrated in Figures 1 to 8, and the system that will be described hereinbelow, may be used as integrated systems for forming the irrigation pipes in themselves by the mere wrapping of the laminate. However, it must be pointed out that said systems may also be used in the form of elongated ribbons which may be adhered to an existing irrigation pipe, which renders the irrigation systems of the present invention remarkably versatile.

In Figures 9 through 11 of the drawings there are illustrated certain other particularly useful embodiments of the present invention, wherein the drip irrigation systems are manufactured also from a pair of plastics sheets 1 and 2, but by means of the "blister" method, in order to provide the winding channels 4 suitably embossed in the thermally deformed sheet 2, such as is clearly illustrated particularly in Figures 9 to 11 of said drawings.

In the embodiment particularly illustrated in Figure 9 a ribbon 23 is formed from the laminate in accordance with the blister method to provide the channels 4, and said laminate 23 is adhered to an existing irrigation pipe 24, whereby the ribbon 23 will extend through the length of said pipe and the collector devices 5 will be arranged next to the emitters 6 to space each channel 4.

In the embodiment illustrated in Figures 10 and 11, the system is identical with the system of Figure 9, but in this case the collector 5 is provided by means of a pair of channels 32 and 33, communicated by means of the transverse channels 34 at spaced lengths and the filtration system is provided by means of the plurality of slits 31 described above in connection with Figure 8, to avoid the entrance of foreign matter into the channels 32 and 33. From said channels 32 and 33 forming the collector 5, the irrigation liquid is transferred through transverse channels 35 to feed said irrigation liquid to the lengths 11 of the winding channel 4, to thereafter deliver it, through the longitudinal communication 12, to a length of opposite direction 13, as clearly illustrated in any of Figures 9, 10 and 11.

The collector devices 5 of the embodiment of Figure 9, however, differ from the above design, while working under the same princle, inasmuch as they are formed by means of a longitudinal channel 7 communicated along its length with a plurality of transverse channels 8, all of them embossed by means of thermal deformation of sheet 2, in order to constitute a comb-like device, whereas sheet 1 has, at the area corresponding to the admission comb-like collector 5, a plurality of elongate slits such as illustrated at 9 in Figure 9, to admit water or irrigation liquid for the above described purposes.From the last arm 8 of the comb-like collector, a longitudinal chamber 10 extends to feed the irrigation liquid to the first ascending stretch 11 of the winding channel 4 to thereafter pass through the longitudinal stretch 12 and finally flow through the descending stretch 13 of said channel to continue flowing along the same for the purposes of reducing the pressure as described above.

The pressure compensating device of the embodiments illustrated in Figures 9 to 11 of the drawings, while working under the same principles of the pressure compensating device described in relation to the embodiments of Figures 1 to 8 of said drawings, differs in t that it adopts the form of a ladder, illustrated by means of reference number 6 in Figure 9 and 10, which communicates by means of a longitudinal channel 15 with the discharge end of channel 4 and comprises substantially a transverse channel 16, approximately of the same width as the passage 4, through which a plurality of crosswisely directed channels 17 extend, said channels 17 having a larger width and communicating with another channel 18, parallel to channel 16, in order to form said ladder-like device, such that all the irrigation liquid discharged by the channel 15 will pass through the channel 16 and thence, through the channels 17 into the channel 18, wherein a plurality of slits 19 is provided along the same, in order to discharge the drip irrigation liquid through said slits which thereby constitute an emitter.

The pressure compensator works by virtue of the fact that the sheet 1 provides a sort of a diaphragm on each one of channels 17 which communicate the transverse channel 16 with the discharge channel 18, such as clearly illustrated in Figures 12 and 13 of the drawings, whereby, when pressure P of the interior of the conducting pipe increases, the sheet 1 will be flexed down as illustrated in Figure 13, thereby partially closing the channels 17 which are joined at their side edges to the sheet 1 by means of the portions 30, to thus compensate for the fluctuations in the pressure, decreasing the flow when the pressure increases and increasing the same when the pressure decreases, in order to maintain a constant volumetric flow as described above in connection with the embodiments of Figure 1 to 8 of the drawings.

It thus may be seen that for the first time an integral drip irrigation system has been provided, formed by a mere moulded laminate of plastics material, which shows considerable advantages as compared to the prior art devices, inasmuch as, due to its flexible nature, it may be transported and stored efficiently and also due to said flexibility, presents the characteristic of constituting a pressure regulator diaphragm in the sections for emitting the drip irrigation liquid, whereby the discharge thereof will be practically constant regardless of the feed pressure of the irrigation liquid to the pipe.

The general structure of the integral drip irrigation system built in accordance with the present invention, formed of a laminate of a pair of plastic sheets, one of which is thermally and permanently deformed to provide all the desired channels, remarkably facilitates the manufacture of said system,.thereby enabling its production in continuous and very simple machines.

Another particularly important advantage of the integral drip irrigation system in accordance with the present invention resides on the fact that, as the collector portions of the device are provided with slits for admitting the drip irrigation liquid, and as said slits are provided in a flexible sheet, said slits may be made as thin as desirable, thereby providing a filtration means which avoids the entrance of any foreign solid material material to the passages, without the need of providing costly separate filtrations systems for the drip irrigation liquid as was the case of the prior art drip irrigation systems.

On the other hand, by providing the discharge openings in the emitter devices of the irrigation system in a closed condition, a better distribution of the drip irrigation liquid discharge is allowed by virtue of the fact that the users may open the outlets only at the desired points, which also prevents the waste of considerable volumes of irrigation liquid.

WHAT I CLAIM IS: 1. An integral drip irrigation system comprising an elongated plastics laminate forming a conduit for carrying irrigation liquid, said laminate comprising a first flexible plastics sheet provided with a plurality of thermally formed cavities therein and a flat second flexible plastics sheet adhered to said first plastics sheet at the most prominent areas of the latter in order to define passages and chambers within said laminate by closing the open side of said cavities, said passages and chambers comprising at least one elongated winding passage extending along the laminate; at least one irrigation liquid admission passage for receiving said liquid and feeding it to one of said at least one winding passage; at least one integral liquid emitter capable of receiving the irrigation liquid delivered through the opposite end of said at least one winding passage and discharging it outwardly of the laminate; an opening for discharge of irrigation liquid provided on one of the faces of the laminate at said at least one emitter; an integrated filtration system for filtering the irrigation liquid which comprises at least a thin slit for retaining solids, provided in said laminate at the side of the laminate opposite the side of the laminate containing said discharge opening and coincident with said at least one admission passage; and an integrated pressure compensating system comprising a non-supported area of said flat second sheet, spanning said at least one emitters, so that, when the pressure in the conduit increases, the non-supported area of said flat sheet acts as a compensating diaphragm which reduces the cross-sectional area of said emitter in proportion to any increase in the pressure within the conduit.

2. An integral drip irrigation system as claimed in claim 1, in which said first flexible plastics sheet comprises a flat strip from one of which major surfaces a plurality of upstanding partitions extend, said passages and chambers being formed between said upstanding partitions.

3. An integral drip irrigation system as claimed in claim I or claim 2, in which said first flexible plastics sheet comprises a sheet containing blister type depressions for forming said passages and chambers.

4. An integral drip irrigation system as claimed in any preceding claim, in which said laminate contains a plurality of said winding passages, continuously arranged throughout the length thereof; each winding passage being formed by a pair of longitudinal side partitions, from which incomplete transverse partitions extend, the latter alternately extending perpendicularly from one and the other iongitudinal partitions so as to form a winding path for the irrigation liquid; said liquid admission passage comprising at least one longitudinal channel extending continuously throughout the length of the laminate between a pair of passage-forming longitudinal partitions, a plurality of grooves being provided through said pair of passage-forming longitudinal partitions extending along the laminate, said emitter comprising a chamber provided at the end of said winding passage and comprising a pair of partitions which extend over the full width of said chamber but are at a distance below the inner surface of said flat second sheet, said partitions being disposed parallel to each other and forming a liquid receiving compartment and a liquid discharge compartment, the gap formed between the upper edges of said partitions and the inner surfaces of said flat second sheet being closed or opened in proportion to the pressure exerted on the other side of said flat second sheet to thereby act as a pressure compensating diaphragm to control the flow of liquid out of the emitter.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. flexibility, presents the characteristic of constituting a pressure regulator diaphragm in the sections for emitting the drip irrigation liquid, whereby the discharge thereof will be practically constant regardless of the feed pressure of the irrigation liquid to the pipe. The general structure of the integral drip irrigation system built in accordance with the present invention, formed of a laminate of a pair of plastic sheets, one of which is thermally and permanently deformed to provide all the desired channels, remarkably facilitates the manufacture of said system,.thereby enabling its production in continuous and very simple machines. Another particularly important advantage of the integral drip irrigation system in accordance with the present invention resides on the fact that, as the collector portions of the device are provided with slits for admitting the drip irrigation liquid, and as said slits are provided in a flexible sheet, said slits may be made as thin as desirable, thereby providing a filtration means which avoids the entrance of any foreign solid material material to the passages, without the need of providing costly separate filtrations systems for the drip irrigation liquid as was the case of the prior art drip irrigation systems. On the other hand, by providing the discharge openings in the emitter devices of the irrigation system in a closed condition, a better distribution of the drip irrigation liquid discharge is allowed by virtue of the fact that the users may open the outlets only at the desired points, which also prevents the waste of considerable volumes of irrigation liquid. WHAT I CLAIM IS:

1. An integral drip irrigation system comprising an elongated plastics laminate forming a conduit for carrying irrigation liquid, said laminate comprising a first flexible plastics sheet provided with a plurality of thermally formed cavities therein and a flat second flexible plastics sheet adhered to said first plastics sheet at the most prominent areas of the latter in order to define passages and chambers within said laminate by closing the open side of said cavities, said passages and chambers comprising at least one elongated winding passage extending along the laminate; at least one irrigation liquid admission passage for receiving said liquid and feeding it to one of said at least one winding passage; at least one integral liquid emitter capable of receiving the irrigation liquid delivered through the opposite end of said at least one winding passage and discharging it outwardly of the laminate; an opening for discharge of irrigation liquid provided on one of the faces of the laminate at said at least one emitter; an integrated filtration system for filtering the irrigation liquid which comprises at least a thin slit for retaining solids, provided in said laminate at the side of the laminate opposite the side of the laminate containing said discharge opening and coincident with said at least one admission passage; and an integrated pressure compensating system comprising a non-supported area of said flat second sheet, spanning said at least one emitters, so that, when the pressure in the conduit increases, the non-supported area of said flat sheet acts as a compensating diaphragm which reduces the cross-sectional area of said emitter in proportion to any increase in the pressure within the conduit.

5. An integral drip irrigation system as

claimed in claim 4, in which each one of said winding passages has forward and backward stretches defined by common longitudinal partitions, in order to distribute the discharge openings of said emitters at less spacing from each other.

6. An integral drip irrigation system as claimed in claim 5, in which each one of said discharge openings is closed by means of an integral plug capable of being cut away to open the discharge openings at the desired places while the remainder are left closed.

7. An integral drip irrigation system as claimed in any of claims 1 to 6, in which said integrated filtration system comprises a plurality of transverse partitions, equidistantly arranged along each channelforming longitudinal partition of said admission passage and a pair of continuous slits extending parallel to said longitudinal partitions and crossing said transverse partitions, whereby between each pair of transverse partitions, said slits will be capable of being opened to an extent sufficient to permit the passage of irrigation liquid, but insufficient to permit the passage of solid matter.

8. An integral drip irrigation system as claimed in any of claims 1 to 6, in which said integrated filtration system comprises at least one series of colinear spaced slits arranged along the longitudinal channel comprising the admission passage.

9. An integral drip irrigation system as claimed in claim 3, in which said laminate contains a plurality of said winding passages continuously arranged throughout the length thereof; each winding passage being formed by an elongated blister-type channel arranged in a zigzag manner; each one of said winding passages is associated with an admission channel comprising an elongated longitudinal blister-type channel and a plurality of elongated transverse blister-type channels which terminate in said longitudinal blister-type channel to form a comb-like device, a plurality of thin slits being provided parallely to said longitudinal blister-type channel and over said transverse blister-type channels, said slits being provided through said flat flexible sheet in order to serve as an integrated filtration system; each one of said winding passages being associated with an emitter which comprises a first transverse elongated blister-type channel, a second transverse elongated blister-type channel parallel to and spaced from said first transverse blistertype channel and a plurality of longitudinal blister-type channels communicating said first and second transverse blister-type channels, thereby forming a discharge device having the shape of a ladder, such that the area of said flat flexible sheet spanning said longitudinal blister-type channels will be arranged in the manner of a diaphragm over said longitudinal blistertype channels, in order to close or open the cross sectional area thereof in response to the pressure on the other side of the diaphragm, said second transverse blistertype channel being provided with a plurality of discharge openings to discharge the irrigation liquid outwardly of the laminate.

10. An integral drip irrigation system as claimed in any preceding claim, in which said laminate is provided with a pair of continuous longitudinal side flaps in order to permit said laminate to be wrapped around itself to place the flaps in overlapped relation to each other, thus permitting of sealing of said flaps in order to form a pipe for conducting the drip irrigation liquid.

11. An integral drip irrigation system as claimed in claim 1 in which said laminate is in the form of an elongated ribbon and is adhered to a drip irrigation pipe on the outer face thereof, openings being provided through said pipe to match the integral filtration elements of said ribbon.

12. An integral drip irrigation system substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.