Abstract:
An in-line system of mini sprinklers comprising a tubular conduit having inner and outer surface areas, and fitted for the flow of pressurized liquids. This tubular conduit has one or more openings along its length, and at least one mini sprinkler unit embedded within the tubular conduit at each opening. Each mini sprinkler unit comprises a liquid distributing assembly and biasing means. As pressure within the tubular conduit increases, inward force exerted by the biasing means is overcome, and the liquid distributing assembly moves outward. As the liquid distributing assembly protrudes beyond the outer surface of the tubular conduit, liquid escapes and sprinkles onto the ground. As pressure is decreased within the tubular conduit, the biasing means force the liquid distributing assembly back to its original position.

Description:
RELATED APPLICATION DATA 
     This application is the U.S. national stage of PCT/IL2006/000223 filed on Feb. 21, 2006, which is based on and claims the benefit of Israeli Patent Application No. 167015 filed on Feb. 21, 2005, the content of each which is expressly incorporated herein in its entirety by this reference. 
     FIELD OF THE INVENTION 
     The invention relates to the domain of irrigation, including agricultural irrigation and flushing (rinsing) areas or wetting surfaces, and fundamentally—in the field of irrigation systems of low volumes, employing mini sprinklers, and the methods for manufacturing these systems. 
     BACKGROUND OF THE INVENTION 
     Irrigation in low volumes is noted and well known in the domain of modern agricultural irrigation. In general, the subject is an irrigation method designated to deliver the water to a specified and as accurate as practical to a defined area, with correct time and simultaneously providing nutrients (fertilizing) materials to the plants together with the water, at the correct dosage and concentration. The common range of pressures and throughput rates of the water in low volume irrigation is 0.5 to 4 atmospheres and 1 to 200 liters per hour. 
     There are two major low volume irrigation methods—drip irrigation and irrigation by sprinkling. 
     The drip irrigation method is based on a system of drip emitters. It is possible to describe a drip emitter as a device accepting water under pressure. The drip emitter reduces the water pressure by directing the water flow through a mechanical mechanism where it encounters resistance to the flow. For example, passing the water through a flow passage formed with a labyrinth of pointed/sharp barriers (set of baffles) positioned in the flow path of the water. The barrier&#39;s labyrinth abates and reduces the water pressure. Thus, following it “journey” through the drip emitter, the water at reduced pressure exits the drip emitter as a dripping current. 
     The advantages of using low volume irrigation through drip emitters, lies in the fact that it brings the water to very accurate designated locations. It also enables providing exact dosages of water and fertilizers, and the drip emitter system can be hidden preventing physical damage to the system combined with inhabiting herbage growth. 
     The disadvantages of using low volume irrigation through drip emitters, is its “pointed” mode of irrigation. Considering its cross section, the wetted volume resembles an “onion” shaped volume that only its relatively small upper (top) layer is located at the upper ground level. But it is this specific layer that is reckoned as critical for developing the roots system of the plants—which is the layer that should be irrigated (as it is richer in fertilizers contents and oxygen percentages). In order to overcome this drawback, farmers tend to increase the number of drip emitters per area unit. This solution—increasing the density of branches and of drip emitters per branch, obviously reduces the advantage of employing the drip emitters method, because the quantity of required equipment increases significantly (and also the deployment tasks become more costly and difficult). 
     A known and noted product in the domain of low volume irrigation by drip emitters is an “Integral Drip Line”, the so-called “In-Line Drip Line”. This is a tubular conduit, that simultaneously with its production process (for example, by a continuous extruding process as a tubular profile or made up from two sheets that are connected flush one to the other at the edges, resulting in a tube with two seams or formed as a tube from a folded sheet that is eventually made as a tube with one seam—along its length), drip emitters units being included within it and embedded in it, located along its length with selected gaps between each and its adjacent members. 
     In an “Integral Drip Line” or in other words—“In-Line Drip Line”, the drip emitter units might be cylindrical (and in this case they are implanted within the tube in all their circumferential area—see for example Eckstein&#39;s U.S. Pat. No. 3,981,452), or flat (and then they are fixed to the inner surface of the tube only in part of their circumferential area), (see for example Gorney et al&#39;s U.S. Pat. No. 4,728,042). 
     Exact opening of apertures (“openings”) in the tube, exactly at the appropriate locations, namely exactly facing the water exits that are formed in the drip emitter units located in the tube along its length, complete the process of producing the integral drip line. Thus, the water flowing within the tube, are shed from it at the appropriate locations, dripping as required. 
     Processes and means for manufacturing integral drip lines simultaneously with the manufacturing process of the tube are familiar and known since long ago. (see for example Mehoudar&#39;s U.S. Pat. No. 5,022,940 covering manufacture of integral drip line in a continuous extruding process of a tubular profile and DeFrank&#39;s et al U.S. Pat. No. 5,522,551 relating to manufacturing integral drip lines from a sheet folded to eventually form a tube with a seam). 
     An outstanding advantage of the integral drip line is the ease of operating it in the field. Deploying the integral drip line and collecting it back (as a large coil) is done with relative ease. The structure of the system also protects the emitter units against physical damage (as they are embedded within the tube and not protruding from it). Because of this advantage, more and more farmers are switching over to irrigation with integral drip lines. Aided by suitable mechanization means, deploying the tubes is done efficiently and all the farmer has to do is to connect it to a water source and close its other end. 
     As we have pointed above, installation of the integral drip line for operation in the field might be mechanized, and hence efficient and at low cost, but the integral drip line do not offer an answer to the problem we posed above—namely the drawback of missing the localized irrigation, namely the deterrent small area on the ground that is wetted by the drip emitters. 
     Referring to  FIG. 1   a ,  FIG. 1   a  is an illustration of existing prior art as cited above, relating to low volume irrigation by employing a sector of integral drip line  10  that is laid on the ground (marked by line  15 ). Drip emitters  20  and  25  embedded within tube  10  at the time of its production (illustrated by dashed lines) form wetting patterns inside the ground, in the image of “onions”  30  and  35 . The relatively small wetted areas on the ground surface wetted by the drip emitters are seen rather distinctively. On the other hand, the relative ease and simplicity of deploying the system, i.e., extending tube  10  on the ground is self-evident. 
     As cited, there is an additional common method in use for low volume irrigation—irrigation by sprinkling. Irrigation by sprinkling is based on using systems of mini sprinklers. A mini sprinkler is a device relatively complicates (a sprinklers&#39; post might be assembled from five to ten parts). Mini sprinklers are described, for example, in Hemsley et al&#39;s U.S. Pat. No. 4,889,287. 
     The farmer is required to deploy a water supply hose in the intended location. Then, he installs the posts for the sprinklers along the hose and in close proximity. Generally, the farmer receives the sprinklers&#39; posts already in their assembled state, and is required to stabilize them on the ground near the water hose he deployed on the ground, for example—by tying them to a pegs driven into the ground or by tying the sprinklers unto a wire that was laid beforehand. Additional tasks that the farmer has to perform are prying holes in the water hose and connect the sprinklers posts to provide a water passage from the hose to the sprinklers. 
     The advantages of the low volume irrigation by mini sprinklers, is that it wets—simultaneously, a relatively large area on the upper ground surface, and hence exploits in an optimal mode the ground upper layer that is best suited for developing the roots. If the farmer manages to deploy the sprinkler&#39;s post at beneficial gaps one from each other, correctly allowing for weighting the water supply rates versus water losses (due to winds, and evaporation to the air) then on the ground—the wetted area that would be obtained, would nor be a collection of separate localized points (as would have been obtained for low volume irrigation using drip emitters), but rather a relatively large assemblage of wetted surfaces that together combine to one large area sector. Instead of the former mentioned “onion” like cross section (as would have been obtained for low volume irrigation using drip emitters), a wide wetted area would be provide, that would prompt a better roots development in the critical ground layer, combined with a more efficient rinsing and driving away salts that accumulate in the ground surface (especially in dray air areas). Thus a micro weather change to the better would be generated—through reducing the temperature and increasing the humidity below the vegetation growth scene, and generating a growth environment that hides the fertilizers spread on the ground. 
     On the other hand, the drawbacks of the low volume irrigation by the mini sprinklers method, lies in the relative complicity required for performing the multi stages installation of the system correctly and efficiently (as we enumerated: deploying the water hose, installing and anchoring the sprinkler&#39;s posts at its vicinity and with suitable gaps between them, connecting water piping from the hose to the sprinklers). Naturally, from the complications linked to the installation, we can understand the costs issue facing the farmer. Deploying the sprinklers system in the field is not mechanized and thus neither efficient nor cheap. The sprinklers assemblage is exposed to the environment and also to physical harm, and disassembling it requires all the above mentioned complicated steps (done backwards: disconnecting the water supply, dismantling the sprinklers from the posts, disassembling each post separately). 
     Referring to  FIG. 1   b .  FIG. 1   b  displays prior art, regarding the execution of low volume irrigation using the mini sprinkler units system  50 . A water hose  55  is deployed at the intended destination on the ground surface (marked by line  60 ). The farmer installs the sprinklers  65  and  70 , along and in the proximity of hose  30 . In the illustrated example, sprinklers  65  and  70  are stabilized on pegs  75  and  80 , respectively, that are driven into the ground. Water hose  55  is perforated and connected, through tubes  85 ,  90  respectively, in order to provide a water flow into the sprinklers. Sprinklers  65  and  70  generate by their concurrent action, circumferential wetted sectors  95  and  100 , which cover a relatively large area on the upper ground surface. On the ground, the wetted area that would be received from the system  50 , would not be a collection of localized points (as would have been obtained for low volume irrigation using drip emitters, see  FIG. 1   a ), but rather an array of wetted areas that together form a relatively large wide and continuous volume. On the other hand, the complications linked to the deployment and dismantling of the system on all the required stages, depict the difficulties clearly and unequivocally. 
     A wide and continuous wetted volume is also required in additional applications, that are not necessarily agricultural, in which use is made of low volume irrigation systems. For example—a method for rinsing minerals (heap leaching) by using solutions that are distributed by sprinklers or spread through drip emitters, (for example, on the heaps of material that was dug from a mine), (see for example Herndon&#39;s U.S. Pat. No. 4,739,973). Any professional experienced in this field would understand that the workers in a mine that wish to use existing systems such as reviewed above (sprinklers or drip emitters) encounter actually the same drawbacks that were encountered by the farmers, as described above. 
     SUMMARY OF THE INVENTION 
     The present invention achieves the advantages of ease in field installation by offering a system amenable to be mechanized, efficient and cheap—those properties of a relatively low costs system, in the manner these advantages are materialized in the low volume irrigation method through an integral drip line, together with the advantages achieved by the other method—the mini sprinkler system—namely wetting large areas on the upper ground surface and generation of a relatively wide, continuing wetting area, as these advantages materialized in low volume irrigation using sprinklers array, as we explained in detail above. 
     The invention is not restricted to solely the field of agricultural irrigation, but rather it obtains the same advantages in other applications such as for example flushing and rinsing minerals, and by its accord it is not restricted to irrigation by a fluid that is water—but is also applicable for irrigating, wetting or flushing using other liquids, (for example, detergents, water mixed up with fertilizer material and the like). 
     In one aspect of the present invention, the current invention constitutes an in-line system of mini sprinklers that comprises a tubular conduit endowed with inner and outer surface areas, fitted for a liquid flow under pressure through it and formed with at least one opening along its length. At least one mini sprinkler unit is embedded within the tubular conduit, coupled to the flow of a liquid within it and mounted to it around the opening. The sprinkler unit comprises a liquid distributing assembly that is mobile through the opening, so that when liquid&#39;s pressure in the tubular conduit increases, the liquid distributor moves and protrudes beyond the outer surface area of the tubular conduit in order to sprinkle the liquid outwards of the tubular conduit. 
     Any professional experienced in this field would understand that a major characteristic of the present invention is that the embedding of the mini sprinkler at least substantially in the tubular conduit exists when the system is at its closed (shut down) state. In other words, when the system is at its closed (shut down) state, the mini sprinkler does not protrude more than a few millimeters from the outer surface area of the tubular conduit, and in the preferred embodiment of the invention—it does not protrude at all. 
     In an additional preferred embodiment of the present invention, several units of mini sprinklers are embedded within the tubular conduit and located along its length with selected gaps between one and each other, and installed, each of them, around an opening. 
     In yet another preferred embodiment, the mounting of the mini sprinklers unto the inner surface of the tubular conduit is done by heat soldering (while exploiting the heat energy accumulated at the wall of the tubular conduit in the course of its manufacturing). 
     In an additional preferred embodiment of the invention, the system includes also means for preventing contamination entities from entering into the sprinkler unit. This is formed at the end of the liquid distributor assembly. Moreover, in another preferred embodiment, the means include a sector that was cut off the wall of the tubular conduit by a thin circumferential groove and remains soldered to the upper end of the liquid distributor assembly. 
     In an additional preferred embodiment, the system includes also means for mounting the tubular conduit in a manner so that the opening from which the liquid distributor assembly protrudes when the liquid pressure increases inside the tubular conduit would be directed upwards. 
     By another and additional aspect, the current invention comprises a mini sprinkler unit that is includeable, at least substantially, within and fixed into a tubular conduit that is fitted for flow of liquid under pressure inside it. The sprinkler unit comprises a body assembly formed with a surface area sector fitted for mounting to a tubular conduit, an inner volume around which the surface area is formed, and a liquid inlet coupled to it. The structure of the sprinkler includes also a liquid distributor assembly installed within the inner volume of the body assembly, and is mobile relative to the body assembly when the liquid pressure increases in the tubular conduit. Thus when liquid&#39;s pressure in the tubular conduit increases, the liquid distributor moves and protrudes beyond the outer surface area sector that are fitted to be mounted on the tubular conduit, and its movement connects the assembly to flow of fluid into it through the liquid inlet of the body assembly. 
     In a preferred embodiment of the sprinkler, the sprinkler comprises a suction preventing and no drain valve means, that is activated when the pressure drops in the tubular conduit. 
     In an additional and different aspect, the present invention embodies a method for low volume irrigation that includes the steps of deploying an in-line system of mini sprinklers, composed of a tubular conduit having inner and outer surface areas, adapted to enable flow of liquid under pressure in it and formed with openings along its length, and of several mini sprinkler units that are at least substantially embedded within the tubular conduit while they are located with certain gaps one from each other, coupled to a flow of liquid within the tubular conduit and mounted on it, each of them around one of the openings, and include each one of them, a mobile liquid distributor assembly. Thus when the liquid pressure increases within the tubular conduit, the liquid distributor assembly moves and protrudes towards beyond the outer surface areas of the tubular. An additional step of the method is the feeding of the tubular conduit with liquid under pressure in a way that the mobile liquid distributor assembly will move and protrudes towards beyond the outer surface areas of the tubular conduit and spread the liquid unto the outside of the tubular conduit. 
     In an additional and different aspect of the present invention, the manner of manufacturing an in-line system of mini sprinklers in accordance with the present invention, embodies a manufacturing method that includes the steps of—continuous manufacturing of a tubular conduit having inner and outer surface areas, adapted to enable flow of liquid under pressure in it, timed feeding and mounting of at least one mini sprinkler unit to the tubular conduit during the process of its continuous manufacturing in a manner that the sprinkler unit would be at least substantially included within in it, and wherein the sprinkler unit includes a body assembly and a liquid distributor assembly that is mobile when liquid pressure increases within the tubular conduit, locating positions of the mini sprinkler units inside the tubular conduit, and forming an opening at the wall of the tubular conduit in a manner that would enable mobility of the liquid distributor assembly through it when liquid pressure increases inside the tubular conduit, so that the liquid distributor assembly would move and protrudes beyond the outer surface area of the tubular conduit. 
     In another and additional aspect of the present invention, manufacturing an in-line system of mini sprinklers in accordance with the present invention is executed in a system made for continuous manufacturing of a tubular conduit with outer and inner surface area, that is fitted for flow of liquid under pressure inside it (for example, a system for continuous manufacturing of the tubular conduit by extruding tubular profile or a system for manufacturing a sheet and connecting it flush with another sheet along their edges by making two seams, or a system for manufacturing a sheet and folding it into a tube with one lengthwise seam). Wherein the system is characterized by that it includes, in addition, a device for timed feeding and mounting at least one mini sprinkler unit to the tubular conduit, during the process of its continuous manufacturing, in a manner such that the sprinkler unit would be substantially included within in it, and wherein the sprinkler unit includes a body assembly and a liquid distributor assembly that is mobile when liquid pressure increases within the tubular conduit and the system includes in addition, a device for locating positions of the mini sprinkler units inside the tubular conduit and a device for forming an opening at the wall of the tubular conduit in a manner that it would enable mobility of the liquid distributor assembly through it when liquid pressure increases inside the tubular conduit, so that the liquid distributor assembly would move and protrudes beyond the outer surface area of the said tubular conduit. 
     In yet another preferred embodiment, the device for forming an openings at the tubular conduit&#39;s wall executes a thin circumferential groove in the wall of the tubular conduit, that bounds a sector which is disconnected from the tubular conduit&#39;s wall but remains secured to an upper (top) surface formed at the end of the liquid distributor assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the figures, in which: 
         FIGS. 1   a  and  1   b  constitute illustrations of prior art referring to low volume irrigation by the integral drip line method and by the sprinklers method, respectively. 
         FIGS. 2   a ,  2   b  and  2   c  constitute illustrations (partly in cross section) of an example of a system for low volume irrigation in accordance with the present invention, describing (a) an in-line system of mini sprinklers in its closed state (before driving the liquid into the system), (b) same system after being filled up with liquid and (c) the system in operation state, respectively. 
         FIG. 3  represents an exploded view (in cross section) of sample components of a mini sprinkler unit that can be mounted unto the inner surfaces of a tubular conduit in accordance with the present invention. 
         FIGS. 4   a ,  4   b ,  4   c  and  4   d  show cross section views of an in-line system of mini sprinklers in accordance with the present invention, in which the mini sprinkler unit illustrated in  FIG. 3  is installed.  FIGS. 4   a  to  4   d , illustrate: 
         FIG. 4   a —the sprinkler, already at the time the tube is being manufactured, is installed on the inner surface area of the tubular conduit; and 
         FIG. 4   b —the system at its close state, wherein an opening was formed on the wall of the tubular conduit as a thin circumferential groove around the upper surface area of the liquid distributor assembly at the time the tube is being manufactured; and 
         FIG. 4   c —the sprinkler at its working stage—while the liquid pressure increases in the tubular conduit, the liquid distributor assembly moves through the opening and protrudes beyond the outer surface area of the tubular conduit; and 
         FIG. 4   d —concurrently with the drop of the pressure in the tubular conduit, the biasing means force the liquid distributor assembly towards the body assembly of the sprinkler, propels the liquid distributor assembly to return and re-enter into the inside (volume) of the sprinkler&#39;s body assembly, wherein simultaneously a circumferential edge formed around the liquid passage flow rate fixer formed in the liquid distributor assembly, moves towards a sealing means that is located at the bottom of the sprinkler&#39;s body assembly, for activating the suction preventing and no drain valve means. 
         FIGS. 5   a  and  5   b  constitute cross section illustrations of an example of an in-line system of mini sprinklers in accordance with the present invention, wherein the tubular conduit was formed by a continuous extrusion process of a tubular profile. The two figures describe the tubular conduit (a) before the liquid is driven to flow in it and (b) at the time the liquid does flow, respectively. 
         FIG. 6  constitutes a schematic illustration of an example of an array for manufacturing the in-line system of mini sprinklers illustrated in  FIG. 5 . 
         FIGS. 7   a , and  7   b  constitute cross section illustrations of an example of an in-line system of mini sprinklers in accordance with the current invention, wherein the tubular conduit was formed as a tube made of two sheets that were connected flush one to the other at the edges, thus forming a tube with two seams. The two figures describe the tubular conduit (a) before the liquid is driven to flow in it and (b) at the time the liquid is driven to flow. 
         FIG. 8  constitutes a schematic illustration of an example of an array for manufacturing the in-line system of mini sprinklers illustrated in  FIG. 7 . 
         FIGS. 9   a  to  9   d  display cross section of the various stages of another embodiment of manufacturing the in-line system of mini sprinklers in accordance with the current invention—wherein the sprinkler unit is assembled in stages, during the and concurrently with the process of manufacturing the tubular conduit (either by continuous extrusion of a tubular profile or by forming it as a tube from two sheets brought flush together at their edges or from a folded sheet). 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     For the sake of convenience, the description of the present invention is presented in terms of agricultural irrigation. As already pointed out, the invention is not restricted solely for tasks of agricultural irrigation, neither is it restricted just to irrigation with water as the only liquid that may be used. On the contrary—the invention is applicable to irrigation, wetting and flushing (rinsing) using other liquids, such as detergents or water in a solution with fertilizing materials and so on. 
     Referring to figures numbered  2   a ,  2   b  and  2   c . These figures constitute illustrations (partly in cross sections) of an example of a system  210  for low volume irrigation example in accordance with the present invention. 
     In  FIG. 2   a , a typical sector of an in-line system of mini sprinklers  210  is presented at its closed state, before driving/forcing liquid to flow into the system. System  210  comprises a tubular conduit  215 , fitted to conduct a flow of liquid under pressure in it and formed in the illustrated sector with three openings  220 ,  225  and  230  along its length. A cross section of mini sprinkler unit  235  is shown in the illustrated sector, contained within tubular conduit  215 , secured to its inner surfaces area  240  around opening  225 . Additional mini sprinkler units (not illustrated) are mounted, each one respectively, around each of the other openings. Each of these mini sprinkler units includes a liquid distributor assembly  245  as in sprinkler  235  shown in the figure. 
       FIG. 2   b  depicts the same system  210  after tubular conduit  215  was filled up with liquid. The profile of tubular conduit  215  was changed accordingly due to the liquid arrival—from a flat profile (see  FIG. 2   a ) to an inflated tubular profile filled with liquid (see  FIG. 2   b ). The liquid distributor assembly  245  is mobile trough opening  225  in a manner that concurrently with an additional increase of the liquid&#39;s pressure within tubular conduit  215  the liquid distributor assembly  245  would move and protrude outwards of the outer surface area  250  of the tubular conduit  215  (in a manner to be explained later while referring to  FIGS. 4   a  to  4   d ). 
     In  FIG. 2   c  system  210  is seen at its operating state—performing low volume irrigation through sprinklers  220 ,  225  and  230 . A further increase of the liquid pressure within tubular conduit  215  brought around, as said, motion of the liquid distributor assemblies  245 ,  255  and  260  through openings  220 ,  225  and  230 , so that they would protrude outwards of the outer surfaces area  250  of the tubular conduit  215 . Each of the liquid distributor assemblies of the sprinklers is now fed by liquid from the tubular conduit  215  and sprinkles it to the surface area around it (in a manner to be explained later while referring to  FIGS. 4   a  to  4   d ). 
     Already at this stage, if we compare the performance attributes of system  210  in accordance with the present invention, as they are illustrated in  FIG. 2   c  to the illustrated prior art ( FIGS. 1   a  and  1   b ) that as cited, depict the current existing low volume irrigating methods, either using an integral drip line (see  FIG. 1   a ) or by a system of sprinklers (see  FIG. 1   b ), than the impressive advantages of the current invention can be appreciated. 
     System  210  as per the present invention achieves the advantages of efficient installation in the field of a relatively low priced system, same as these advantages are embodied in the low volume irrigating method using an integral drip line. The tubular conduit  215  contains in it the sprinklers units and thus practically constitutes an integral sprinklers line. As an integral sprinklers line, system  210  is easy to operate in the field. The integral sprinklers line  210  is given to quick deployment and to fast retrieval and rolling with relative ease. The structure of the system also protects the sprinklers from physical impact (harm) as they are embedded within the tubular conduit and not sticking out from it. Any professional experienced in this field would understand that with suitable mechanization, deploying system  210  can be performed swiftly and efficiently and the farmer has only to connect tubular conduit  215  to a water source on its one end and to close its other end (or, in another application, for example flushing (rinsing) minerals, the mine laborer would act the same: connect the tubular conduit  215  to the source of the rinsing liquid—and not forget to close the other end). 
     Any professional experienced in this field would understand that in order to obtain the advantage we were describing above, a major characteristic of the invention is the embedding of the sprinkler within the tubular conduit, that actually occur when the mini sprinkler is at least substantially embedded in the tubular conduit when it is in its closed state. In system  210  the sprinklers are totally “buried” within the tubular conduit, namely—when the system is in its closed state, they do not protrude beyond the outer surface area of the tubular conduit. At the same time, even if the sprinkler would protrude slightly from the outer surface of the tubular conduit (for example up to 4 mm), this presented advantage of the system in accordance with the invention would prevail. 
     Similarly, system  210 —in accordance with the invention, achieves the sought for advantages of wetting the upper layer of the ground and the generation of a relatively wide and continuing area, as these advantages are embodied in low volume irrigation by an array of sprinklers. In agricultural irrigation applications, system  210  wets, simultaneously, a relatively large area of the ground upper layer, and thus exploits in an optimal manner the ground upper layer for development of roots. On the ground surface (marked in  FIG. 2   c  by line  265 ), the area of wetting that would be received from irrigating by a system such as system  210 , constitutes an array of relatively large wetted areas, that together form one relatively large wetted area  270 . System  210  produces a wide and continuing wetting band that would enable as said, the development of a wide upper roots system in the upper layer of the ground (that is, as explained, the more fertile and well aired layer). Thus system  210  enables optimal (and maximal) use of the water and the fertilizer by the roots, together with performing more efficient rinsing and driving away salts that accumulate in the ground surface (especially in dray air areas). It can be said that it creates a micro change of the climate, namely reducing the temperature and increasing the humidity, generating a growth environment that “hides”—by driving into the ground (a beneficial result) the fertilizers spread on the ground. 
     Thus, in the operation mode of system  210 , a general method for low volume irrigation is embodied (and as said, this kind of irrigation is not restricted to agricultural applications exclusively, but rather it can serve other chores of such as rinsing minerals or wetting surfaces). The subject is the availability of a general method that might be materialized in other systems that would be assembled in accordance with the invention. 
     A method that includes the steps of deploying an in-line system of mini sprinklers that is made if a tubular conduit having inner and outer surfaces, fitted for flow of liquid under pressure in it and formed with openings along its length, and several mini sprinkler units that are embedded within the tubular conduit wherein they are located along its length at given gaps between them, and mounted, each of them, around one of the openings. The sprinkler units comprises, each one of them, a liquid distributor assembly that is mobile in a manner that when the liquid pressure inside the tubular conduit increases, the liquid distributor moves and protrudes beyond the outer surface of the tubular conduit. In the second steps driving liquid under pressure occurs within the system&#39;s tubular conduit in a manner that the liquid distributors would move and protrude beyond the outer surface area of the tubular conduit and subsequently spread liquid outwards from the tubular conduit. 
     Any experienced professional would understand that in order to ensure the continuing wetted path  270  as n  FIG. 2   c , it is required to position the tubular conduit  215  relative to the ground top surface so that openings  220 ,  225  and  230 , through whom the liquid distributing assemblies move and protrude outwards, so that they will be directed in a direction that is substantially perpendicular to the ground surface  265 . In the example illustrated in  FIGS. 2   a  to  2   c , this direction is achieved merely by laying the tubular conduit  215  simply flat and empty from liquid on the ground (see  FIG. 2   a ), while strictly ensuring the openings directed upwards, so that even its being filled up with liquid concurrently with the increase of liquid pressure inside it would not topple it. Similarly, any experienced professional would understand that means (not illustrated) may be added to system  210  for anchoring the tubular conduit  215  in a manner that the openings would substantially remain in this upwards directed position—perpendicular to the ground. For example pegs (“peg means”) might be driven into the ground along tubular conduit  215  and anchor it to the pegs in the correct orientation, independent of the exact anchoring mode—whether the tubular conduit  215  is laid on the ground or hanged correctly above it, or hanging a wire means unto which the tubular conduit  215  would be hanged (in the latter case, of the tubular conduit being hanged up in the air, it is also possible to direct the opening downwards toward the ground). 
     Referring to  FIG. 3 .  FIG. 3  represents an exploded view (in cross section) of sample mini sprinkler unit  235  components that was illustrated in  FIGS. 2   a  to  2   c  as it is secured to inner surface  240  of tubular conduit  215 . 
     Any professional would understand that the shown structure of sprinkler  235  is presented solely as an example, and that an in-line system of mini sprinklers according to the present invention might include mini sprinklers having a different structure that however, are also amenable to being secured substantially within the tubular conduit, each one of them around an individual opening as cited, wherein they also include a liquid distributor assembly that is mobile through the opening, in a manner that with the increasing liquid&#39;s pressure in the tubular conduit the liquid distributor moves and protrudes beyond the outer surface area of the tubular conduit. 
     A mini sprinkler unit includes, as cited, a mobile liquid distributor assembly  245  and also a body assembly  310  and biasing means  315 . 
     Body assembly  310  comprises three components—body component  320 , liquid inlet component  325  and sealing means  330 . Sprinkler  235  also includes biasing means  315  and mobile liquid distributor assembly  245  that includes only two components—liquid passage flow rate fixer  335  and distributor component  340 . 
     Any professional would understand that the relatively small number of components) making up mini sprinkler  235  (six in the illustrated example), contribute to lowering the costs involved in manufacturing it and assembling it in the system. 
     Body component  320  is manufactured by a mold injection process and formed as an elongated part. Voids are formed in body component  320  in order to reduce its weight and save on raw materials (one such void, for example, is designated  343 ). Body component  320  is formed with a surface area sector  344  at its upper part. Surface area sector  344  as far as their geometric outline is concerned are suited for installation on the inner surface of the tubular conduit (an arch like outline in its shape with cross section dimensions that match the expected outline of the cross section of the inner surface of the tubular conduit, when it is filled up with liquid). Surfaces areas  344  are formed around an inner volume  345  formed in the body along its entire length. Inner volume  345  is formed from opening  346  that enables the movement of liquid distributor assembly  245  through it (in a manner that would be explained later on while referring to  FIGS. 4   a ,  4   b .  4   c  and  4   d ), from a conical bracket  347  linked to opening  346 , from circumferential channel  348  with protruding edges  349  that is formed at bottom of a conical bracket  347 , and from wall  350  that is linked to circumferential channel  348  and formed at its bottom part with circumferential groove  351  that is fitted to serve as a bracket in an undercut type of connector with liquid inlet component  325 . 
     Liquid inlet component  325  is also manufacture by injection and formed as a quasi “glass” with a flat bottom  352 . Liquid inlet component  325  is made to fit installation inside the inner volume  345  of body component  320 . Flat bottom  352  of liquid inlet  325  is formed with a plurality of through holes  353  that, as we will see later on, serve as a liquid straining filter. A ring like groove  354  formed at the center of a flat bottom  352  and with it dimensions fitted to enable the anchoring of sealing means  330  in it. The circumferential wall  355  of liquid inlet  325  is fitted for being installed within internal volume  345  of body component  320  while being as well in contact with wall  350 . On the circumference of liquid inlet  325 , a circumferential bulge  355  is formed that upon installation is adapted to enter into groove  351  (so that, as cited, it generates an undercut type of connector with body component  320 ). The upper surface area  357  of circumferential wall  355  is formed with an external step  358  around their circumference. 
     Sealing means  330  is, in the illustrated sprinkler example, an elastomer seal in a configuration of an o-ring that is fitted in its dimensions, as cited, to be installed within the ring like groove  354 . 
     Biasing means  315  is—in the illustrated sprinkler example, an elastomer ring component. Elastomer ring  315  is formed with opening  361 . The surface area  362  of elastomer ring  315  are formed at their ends, on both sides—top and bottom, with circumferential bulges  363  (on the circumference of the ring&#39;s inner part), and— 364  (on the circumference of the ring&#39;s outer part). Bulges, that as we will see later (would be explained later when referring to  FIGS. 4   a  to  4   d ), serve for anchoring biasing means  315  at its outer part to the circumference of the inner volume  345  of body assembly  310 , and at its inner part, to the outer circumference of the mobile liquid distributor assembly  245 . 
     Liquid passage flow rate fixing component  335  is formed by injection in a quasi “piston” configuration that has a central passage  371  along its total length. Central passage  371  is formed with liquid entrance  372  and liquid exit  373 . Liquid entrance  372  is formed with a “lip”  378  around its circumference in a manner that enables sealing contact between it and sealing means  330 . Liquid exit  373  is formed with a circumferential wall  374  that is adapted to installation by pressure within distributor component  340 . Around the external circumference of component  335  a circumferential bulge  375  is formed endowed with protruding edges  375  on its one side. As we will see below, when referring to  FIGS. 4   a ,  4   b ,  4   c  and  4   d , a circumferential channel  377  that is formed between the bulging edges  376  to the component body, serves for anchoring the inner part of the biasing means  315  to the mobile liquid distributor assembly  245 . 
     Distributor component  340  is also manufactured by injection molding in quasi “piston” configuration with a central passage  381  that is adapted by his dimensions to include within it by pressured installation the circumferential wall  374  of liquid passage flow rate fixer component  335 . Around the bottom of distributor component  340 , a circumferential bracket  382  is formed with edges  383 . As we shall see below, when referring to  FIGS. 4   a  to  4   d , circumferential bracket  382  also serves for anchoring the inner part of biasing means  315  to the mobile liquid distributor  245 . At its upper part, the distributor component  340  is formed with a number of ribs  384  around its circumference. Passages  385  that are hence formed, between ribs  384 , serve for the liquid&#39;s passage and distribution. At the upper end of distributor component  340 , on the ribs  384  and as an integral part of the liquid distributor component  340 , an upper plane  386  is formed. On its inner side that faces towards central passage  381 , that upper plane  386  is formed as a stepped cone  387 . Stepped cone  387  serves to direct the liquid flow towards passages  385 . On its outer side an upper plane  386  is formed at its center with a protruding ring  388 . 
     Referring to the  FIGS. 4   a ,  4   b ,  4   c  and  4   d . The  FIGS. 4   a ,  4   b ,  4   c  and  4   d  show cross section views of example of an in-line system of mini sprinklers  410  in accordance with the present invention. In-line system of mini sprinklers  410  comprises a tubular conduit  411 . Unto its inner surface area  412 , a mini sprinkler unit  235  is secured. The parts of components of mini sprinkler  235  are illustrated in  FIG. 3 . 
     As cited, any professional in this field would understand that to the same extent and in accordance with the invention, mounting the mini sprinkler unit might be done either to the wall of the tubular conduit or to its outer surface area, or even combined, but in any case it is mandatory that in the closed state of the system, the mini sprinkler unit would be at least substantially included within the tubular conduit and not protrude too much from the outer surface area of the tubular conduit (for example—not more than 4 mm), so that a the system in accordance with the invention would really be an in-line system of mini sprinklers. 
     System  410  is illustrated in  FIGS. 4   a ,  4   b ,  4   c  and  4   d , as it is seen at the different stages of the process of its manufacturing and its operation. System  410  is characterized by in its production, sprinkler  235  is mounted to the internal surface  411  while already completely assembled. 
     Tubular conduit  411  in  FIGS. 4   a ,  4   b ,  4   c  and  4   d , is only partly illustrated. Any professional in this field would understand (and we will continue to elaborate on this subject when referring to  FIGS. 5   a ,  5   b ,  6 ,  7   a ,  7   b , and  8 ), that in a system in accordance with the invention, and hence in system  410 , the tubular conduit might be formed by continuous extrusion of a tubular profile, or from two sheets that are coupled flush one to the other at the edges or also as a tube made of a folded sheet. 
       FIG. 4   a  shows a cross section view of sprinkler  235  immediately after it was secured to the inner surface area  412  of tubular conduit  411 . It has to be remembered that at this stage, the manufacturing process of system  410  in accordance with the invention was not yet completed because the opening in the tubular conduit, that enables the movement of the liquid distributor assembly of the sprinkler through it, was not yet formed. 
     As cited, system  410  is characterized in that the sprinkler units installed in it are secured to the inner surface area of the tubular conduit after they were assembled, each of them, at an earlier stage. Thus, in the example illustrated in the figure, mini sprinkler unit  235  has been already assembled at an early stage— 
     Elastomer ring  315  was inserted into the inner volume of  345  of body component  320  through its bottom part. Outer upper circumferential bulge  364  of elastomer ring  315  was positioned in circumferential groove  348  of body component  320 . Liquid passage flow rate fixer  335  was also inserted into inner volume  345  of body component  320  from its bottom part direction. Inner lower  377  of circumferential bulge  363  of elastomer ring  315  was positioned in circumferential groove of liquid passage flow rate fixer  335 . Elastomer seal  330  was positioned inside ring like groove  354  that is in liquid inlet component  325 . At this stage, liquid inlet component  325  was inserted into internal volume  345  of body component  320  from its bottom part direction. An undercut type connector was formed between liquid inlet component  325  to body component  320 , as a result of circumferential bulge  335  becoming interlaced with groove  351 . In this state lower outer circumferential bulge  364  of elastomer ring  315  was positioned inside step  358  of liquid inlet component  325 . By this manner, elastomer ring  315  was anchored at its outer circumference to the inner volume circumference  345  of body assembly  310 . At this stage, distributor component  340  was inserted through opening  346  of body component  340 . Distributor component  340  was installed by pressure on liquid passage flow rate fixer  335 . At this state, upper inner circumferential bulge  363  of elastomer ring  325  was positioned within circumferential bracket  382  of distributor component  340 . By this manner, elastomer ring  315  was anchored at its inner circumference unto the outer circumference of liquid distributor assembly  245 . 
     Attention should be given to the fact that at this stage circumferential edge  378  of liquid passage flow rate fixer  335  is biased through elastomer ring  315  into a sealing contact with elastomer seal  330  located at the liquid inlet component  325 . 
     At this stage, the task of assembling sprinkler  235  was terminated, and it is, now that it is assembled, ready for being secured unto the inner surface area  412  of tubular conduit  411 . 
     Any professional would understand (and we will continue to elaborate on this subject when referring to  FIGS. 5   a ,  5   b ,  6 ,  7   a ,  7   b , and  8 ) that securing sprinkler unit  235  unto the inner surface area  412  of tubular conduit  411 , might be executed by heat soldering, (while exploiting the heat energy accumulated at the wall of the tubular conduit in the course of its manufacturing). In case it is desired to utilize the heat soldering possibility, any experienced professional would understand that at least the surface area sector  344  has to be manufactured from a material that is solderable by heat to material from which the tubular conduits are manufactured in the irrigation industry (for example, polyethylene). Among the additional possibilities for securing a mini sprinkler to the inner surface area of the tubular conduit are securing by heat soldering as described above but with the addition local heating, or using adhesives and thinners. 
     Sprinkler  235  is secured to inner surface  412  (for example, by heat soldering as explained) in a manner that surface area sector  344  that is formed at the upper part of body component  320 , is secured to the inner surface of tubular conduit  411  along the quasi arc outline as cited in which a surface area sector was formed (in accordance with the expected outline of the inner volume of the tubular conduit, when it is filled up with liquid). Any professional would understand that forming body component  320  as an elongated part (see  FIG. 3 ), facilitates aligning and feeding sprinkler  235  in the appropriate orientation for being installed, so that thus the quasi arch outline of surface area sector  344  would achieve accurate contact with the inner surface area  412  of tubular conduit  411 . 
     At the same time, ring  388  formed at the upper part of distributor component  340 , is also secured to the inner surface area of tubular conduit  411 . Any professional would understand that because the distributor component is non directional in its mounting or in other words, it may be installed on liquid passage flow rate fixer  335  in any desired relative orientation between them, ring  388  that protrudes from upper plane  386 , ensures contact with the inner surface of the tubular conduit, and this without having to force the inner surfaces of the tubular conduit to suit themselves to the outline of plane  386 . In case it is desired to exploit the heat soldering technique, any professional would understand that at least ring  388  has to be manufactured form a material that is solderable by heat to the materials from which the tubular conduits are manufactured in the irrigation industry (for example, polyethylene). 
       FIG. 4   b  is a cross section view of system  410  at the stage it is ready for use. System  410  is illustrated at its closed state, wherein an opening  413  was formed already at the manufacturing stage, on the wall of the tubular conduit  411  as a thin circumferential groove  414  around the outer plane  386  of the liquid distributor assembly  245 . 
     Forming opening  413  at this stage, leaves a disconnected sector  415  (from wall of tubular conduit  411 ), that is secured to the liquid distributor assembly  245  (as a result from heat soldering sprinkler  235  to inner surface  412  of the tubular conduit). A thin circumferential groove  414  bounds the dimensions of the cut-off sector  415 . As cited circumferential groove  414  is formed to be, thin at its thickness dimension—for example 0.1 to 0.3 mm. 
     Any professional would understand that, in the closed state at which system  410  is illustrated ( FIG. 4   b ), a cut off sector  415 , as well as the minimal thickness of circumferential groove  414 , constitutes a means for preventing penetration of contaminants into sprinkler unit  235 . Means for preventing contaminants penetration formed at the end of liquid distributor assembly  245 , that concurrent with increasing liquid pressure in tubular conduit  411 , would move through opening  413  and protrude beyond the outer surface area of the tubular conduit (and see also more when referring to  FIG. 4   c ). 
     As cited, system  410  is illustrated at its closed state. In this state, driving liquid to flow into tubular conduit  411  would not necessarily bring about the activation of liquid distributor assembly  245  to move through opening  413 . Liquid would pass via through holes  353  that serve as a sifting filter, and enter volume  416  but as long as the pressure would not be higher than a threshold given to be defined, circumferential edge  378  of liquid passage flow rate fixer  335  would continue to be biased by elastomer ring  315  to a sealing contact with elastomer seal  330  located at liquid inlet component  325 . 
     Any professional would understand that we actually refer to a structure of a valve that comprises a suction preventing and no drain valve means. Means for biasing the liquid distributor assembly  245 —elastomer disk  315  in the illustrated example, biases the circumferential edge  378  to a sealing contact with a sealing means—namely elastomer seal  330  in the illustrated example, in a manner that prevent inwards suction of external entities at the time of closing or opening of the liquid pressure in the tubular conduit  412  and also prevents passage of liquid from liquid entrance void  416  formed in body assembly  310 , to the liquid passage flow rate fixer  371 , and this as long as the liquid distributor assembly  245  was not yet activated to move due to liquid pressure increase beyond a threshold that is given to be defined, within tube  412 , 
     Any professional would also understand that a sealing contact between liquid passage flow rate fixer  335  to liquid inlet component  325  might also be achieved without resorting to use elastomer seal  330 , namely—by biasing the circumferential edge  378  to direct contact with the surface area of the flat bottom of the liquid inlet component  325 . Alternatively, the elastomer seal  330  might be positioned even on the surface of circumferential edge  378 . 
       FIG. 4   c  is a cross section view of system  410  at its working state. With pressure increasing in the tubular conduit  411 , liquid distributor assembly moves through opening  413  and protrudes beyond the outer surfaces  417  of tubular conduit  411 . 
     The liquid that underwent filtering via the through holes  353 , from tubular conduit  411  to void  416 , exerts a pressure on elastomer ring  315 . Liquid pressure increase in the tubular conduit increases the pressure generated, as cited, in volume  416 . This pressure eventually overwhelm the biasing force of elastomer ring  315  (the biasing force responsible for moving liquid distributor assembly  245  towards liquid inlet component  325  of body assembly  310 ). Overcoming the biasing force of elastomer ring  315  brings about its stretching while the stretching of the ring results in propelling liquid distributor assembly  245  to move upwards relative to body assembly  310 , via opening  413 . The pressure in volume  416  stretches elastomer ring  315  until a contact is achieved between it and conic bracket  347  formed in body component  320 . At this state, edge  378  moved away from its sealing contact with seal  330  and the flow of the liquid passes to central passage  371  and from there it is directed by a stepped cone  387  to passages  385 . From these passages  385  the liquid is sprinkled around the circumference of sprinkler  325 , in the direction of the arrows marked  418 . 
       FIG. 4   d  is a cross section view of system  410  at the time the liquid pressure in tubular conduit  411  starts to drop. In this state of decreasing pressure, the biasing means force liquid distributor assembly  245  to move towards the body assembly of sprinkler  235 . In the illustrated example, elastomer ring  315 , drives liquid distributor assembly  245  to return and move in the opposite direction—to converge towards body assembly  310  of sprinkler  235 . Elastomer ring  315  becomes disconnected from conical bracket  347  and is drives circumferential edge  378  to move towards sealing means  330  for generating a valve preventing suction and no drain valve means. Concurrently, disconnected sector  415  moves and converges into opening  413 , forming an efficient means for preventing penetration of contaminant into sprinkler  235 . 
     As we have pointed above, the structure of sprinkler  235  and its operation mode as were described in relation to  FIGS. 3 and 4   a  to  4   d , were only an example, and an in-line system of mini sprinklers in accordance with the present invention might include mini sprinklers of very different structure or operation manner. For example, a sprinkler that would be intended for systems according to this invention, but will serve for flushing (rinsing) minerals in mines, might not include at all a suction prevention and no drain valve means. Moreover, the structure of the mini sprinkler  235  itself, might include different components, for example, any experienced professional would understand that the biasing means for forcing the liquid distributor assembly towards the body assembly of the sprinkler might just be a spring means, and not necessarily an elastomer disk as was described up to now. 
     A prominent advantage of the current invention, is the capability to manufacture an in-line system of mini sprinklers in accordance with the invention, such that plurality of mini sprinklers would be included in the tubular conduit and secured to it at pre designed gaps and distances one from another, and this would be done simultaneously with the actual running production of the tubular conduit, without having to stop the regular production line of the tubular conduit, whether we are talking of a production line by extrusion of a tubular conduit that has a hollow tube profile with no seams or as a tubular profile made up from two sheets that are connected flush one to the other at the edges, resulting in a tube with two seams, or also just formed as a tube from a folded sheet that is eventually made as a tube with one seam along its length. 
     Referring to  FIGS. 5   a  and  5   b . The figures show in a cross section view, an example of an in-line system  510  of mini sprinklers  535  in accordance with the present invention, wherein the tubular conduit  511  was formed by a continuous extrusion of a tubular profile. Namely, the tubular conduit was manufactured as a hollow profile requiring no seams.  FIG. 5   a  shows the tubular conduit  511  before the liquid was made to flow into it. In  FIG. 5   b  tubular conduit  511  is shown when tubular conduit  511  is blown up with the liquid inside it, wherein the liquid distributor assembly  545  of sprinkler  535 , protrudes through opening  513 , beyond tubular conduit  511  outer surface area. 
     Referring to  FIG. 6 ,  FIG. 6  constitutes a schematic illustration of an example of an array  610  for manufacturing the in-line system of mini sprinklers  535  illustrated in  FIGS. 5   a  and  5   b.    
     Any professional experienced in the field of extrusion recognizes systems and methods for continuous production of hollow profiles while embedding in them discrete components (for example—drip emitter units if we refer to a production line for manufacturing integral drip line with drip emitters inserted in it along its length). Another example might be the case wherein while in the extrusion process, a single continuous item is embedded in the tube, e.g. an electric cable coated with an extruded continuous polymer envelope. 
     System  610 , hence includes for example, devices that are known and recognized in that field., e.g., a cross head  611 , calibration means  612 , cooling baths  613 , puller  614  and roller  615 . 
     But, as different from the known and recognized production lines, system  610  includes in addition a device  620  for continuous feeding of the mini sprinkler units  535  through the passage in cross head  611  and installing them on the inner surface of the tube being extruded  511 . An additional devices are device  621  for locating the mini sprinklers  535  within the extruded tube together with a device  622  for forming openings  513  at the wall of the tubular conduit, in accordance with the indications received from the locator device  621 . Openings that would enable the movement of the liquid distributor assembly  545  through the opening as cited, so that the liquid distributor assembly  545  would pass through the opening upon the growing liquid pressure and protrude to beyond the outer surfaces areas of the tubular conduit in accordance with the invention. 
     Device  620  includes accumulation and feeding means of pre assembled sprinkler units  535 , for bringing them through the passage at the extruder cross head  611 , at a pre defined accurate timing and at a constant selected orientation, to the contact point with the inner surface area of the tubular conduit (for example, at the location of the calibrator opening or inside it). 
     Any professional in this field would understand that the cited accumulation and feeding means necessitated using automation and control means (for example—vibrating means that directs the sprinkler units to the correct orientation, a piston or a servo motor for timely feeding the sprinkler units on a track means toward the inner surface of the extruded tube, speed control circuitry linked to the puller located at or near the end of the production line). 
     Device  621  is located after cooling bath  613 . The locator device detects the locations of the sprinklers within tubular conduit  511  and times the operation of device  622  by providing indications regarding the locations of the sprinkler units. Any professional in this field would understand that for locating the sprinkler units, device  621  might activate sensor devices of various kinds, e.g., a wheel connected to a micro switch and sensing the “bulge” created by the sprinkler unit within the tubular conduit, an optical or a heat sensor and so on. 
     Device  622  is located down the production line following locator device  621  and timed to act in accordance with indications received from it. In systems wherein the cut off sector are designed to also serve as part of the cited contamination preventing means (see same for  FIGS. 4   a  to  4   d ), the opening is formed as a thin circumferential groove, while leaving a sector connected to the liquid distributor assembly of the sprinkler. Any professional would understand that forming these openings at the wall of the tubular conduit might be done, for example, using a revolving quasi “glass” cutting means, a laser beam, or a revolving knife. 
     At the same time it is to be remembered that due to the time consuming nature of forming the openings, while the tubular conduit keeps advancing all the time (being pulled by puller device  614 ), device  622  might be activated while moving in parallel to and in conjunction with the tubular conduit (and this means that a speed measurement and control circuitry is required, coupled to the puller operation). 
     Referring to  FIGS. 7   a  and  7   b . The figures show cross section illustrations of an example of an in-line system  710  of mini sprinklers  735  in accordance with the current invention, wherein the tubular conduit  711  was formed as a tube made of two sheets  722  and  723  that were connected flush one to the other at the edges, thus forming a tube with two seams  724  and  725 .  FIG. 7   a  shows the tubular conduit  711  before the liquid is driven to flow in it. In  FIG. 7   b , the tubular conduit  711  is seen swollen with the liquid that filled it up, wherein liquid distributor assembly  745  of sprinkler  735  is protruding from opening  713  outwards to beyond the conduit outer surface area. 
     Referring to  FIG. 8 .  FIG. 8  constitutes a schematic illustration of an example of a system  810  for manufacturing the in-line system of mini sprinklers  710  that are illustrated in  FIGS. 7   a  and  7   b.    
     Any professional experienced in the extrusion field knows and recognizes systems and methods for continuous manufacturing of a tube made of two sheets that following joining them flush along their lengths while discrete components are mounted to the surface of one of them that would constitute part of the inner surface of the tube (for example, units of drip emitters in case we are describing a line for manufacturing an integral drip line with discrete drip emitters along its length). System  810  comprises, thus, inter alia—first extruder head  811  for manufacturing one of the sheets,  722 , second extruder head  812  for manufacturing the second sheet,  723 , a device  813  for bringing the sheets  722  and  723  flush together at their length edges (while producing seams at the edges by heat soldering either through exploiting the latent heat generated during the extrusion process or by local heating, or by melting additional material especially for this purpose), a puller  815  and a roller  816 . 
     However, in distinction from other recognized production lines and similar to system  610  that described when referring to  FIG. 6 , system  810  includes in addition, device  820  for timed feeding of mini sprinkler units  835  and installing them on the surface of sheet  722  (the sheet that after the coupling of the two sheets  722  and  723  one to the other, would constitute part of the inner surface area of tube  711 ). Additional devices are device  821  for detecting the locations of the mini sprinklers  735  inside the tube, and device  822  for forming openings  713  at the wall of the tube, according to indications received from device  821  (locations detecting device). The openings are formed in a manner that enables the movement of the liquid distributor assembly  745  through the opening as cited, upon the liquid pressure rise inside the tubular conduit, so that the liquid distributor assembly moves and protrudes beyond the outer surface area of the tubular conduit in accordance with the invention. 
     Device  820  includes means  823  for storing pre assembled sprinkler units  735  and mobile means  824  for transporting sprinkler units  735  to the contact point between them and the surface area of sheet ( 722  the sheet that after connecting the two sheets  722  and  723  one to the other would constitute part of the inner surface area of tube  711 ). Mobile means  824  is positioned between the first extrusion head  811  to the second extrusion head  812  and propels the sprinkler units  735  for bringing them in correct directional orientation and at the right timing (in accordance with the advancing speed of puller  814  and the gap that are meant to be received in system  710  between one sprinkler unit to the next one). The sprinkler units thus are positioned on the inner surface area for being soldered by heat to it, wherein as cited after sheets  722  and  723  have been brought together they form the tubular conduit  711 . Device  820  might also include support means  825  in order to support sheet  722  at the time sprinkler units  735  are being soldered on it (any professional would also understand that support means  825  might also have mobility capability). The mobile device and the support device can ensure that the sprinkler units would be properly accompanied as long as the mounting of the units on the surface area of sheet  722  was not completed. 
     Any professional this field would understand that the storage means and the mobile means as cited, dictates integration with automation and control capabilities (for example—a vibrating means leading the sprinkler units to correct location and proper orientation, a piston or a servo motor for feeding the sprinkler units to their designated positions, speed control circuitry linked to the puller down the production line and so on). 
     Device  821  is located towards the end of the production line, following device  813  that combined the two sheets  722  and  723  together at their edges, producing tubular conduit  711  with two seams  724  and  725 . Similarly to the presentation given above for device  621  (referring to  FIG. 6 ), the device detects and locates the positions of mini sprinkler units  735  as they are installed inside tubular conduit  711  and provides correct timing for the operation of device  722  by providing indications of the locations of the sprinkler units. 
     Device  822 , similarly to the discussion above relating to device  622  (referring to  FIG. 6 ), is located on the production line following device  821  and timed to act in accordance with the indications received from it. 
     Any professional would understand that also a known system for manufacturing a tubular conduit from one sheet that is folded into produce a tube with a single seam (resulting from connecting their length edges) might serve as a basis for continuous manufacturing of an in-line system of mini sprinklers in accordance with the invention, similarly to the production systems that we presented above (when referring to  FIGS. 6 and 8 ). The system would include in addition—a device for timed feeding of the mini sprinkler units and installing them on the surface area of the sheet, that after it being folded would become the inner surface area of the tubular conduit. The feeding device would be positioned between the extrusion head that produces the sheet and the folding device. In addition the system would include devices similar to the manufacturing systems we presented above (when referring to  FIGS. 6 and 8 ). 
     Referring to  FIGS. 9   a  to  9   d . The figures show, in cross section view, the stages of another embodiment of manufacturing an in-line system of mini sprinklers  910  in accordance with the invention, in this example, the mini sprinkler unit  935  was not pre-assembled as was the case before (when referring to  FIGS. 4   a  to  4   d ,  5   a  and  5   b ,  6 ,  7   a  and  7   b  and  8 ), but rather assembled in stages, during the process of manufacturing the tubular conduit. 
     The structure of sprinkler  935  and its operation mode are similar to the structure of sprinkler  235  and its operation mode, as they were described when referring to  FIGS. 3 and 4   a  to  4   d , but any professional would understand that it was intended solely as an example, and that an in-line system of mini sprinklers in which the sprinklers installed in it are assembled one by one in a continuum of stages—during the process of manufacturing the tubular conduit, might include mini sprinklers of a different kind of structure and different operation mode. 
     In the illustrated example, the assembly by stages of a sprinkler unit  935  embedded in tubular conduit  911  that was manufactured by continuous extrusion of a tubular profile is described. But any professional in this field would understand that the described embodiment might also be materialized when the tubular conduit was manufactured from two sheets combined together or from one folded sheet. 
       FIG. 9   a  shows the body assembly  931  of the sprinkler installed on inner wall  912  of tubular conduit  911 , wherein at this stage, in the body assembly there is installed only part of the sprinkler&#39;s liquid distributor assembly. At this stage only the liquid passage flow rate fixer  936  and the biasing means (in the illustrated example—an elastomer disk  915 ) are included. Installing the body assembly “as is” (assembled with only the above mention components), might be accomplished by feeding device as we discussed in referring to  FIG. 6  (where the subject was the tubular conduit formed by a continuous extrusion of a hollow profile). By the same standards, any professional would understand that if instead we would have been referring to a tubular conduit formed of two sheets or one folded sheet, then the feeding device would be adapted to those embodiments (as such a device was described in referring to  FIG. 8 ). 
       FIG. 9   b  shows the formation of opening  913  in the wall of tubular conduit  911 . Opening  913  is formed in such a manner that it would enable later in the manufacturing process to install the distributor component through it, and then—during the system operation time, the movement of the liquid distributor assembly through it when the liquid pressure rises, as in all similar cases. Thus, in accordance with the invention, the liquid distributor assembly would move and protrude beyond the outer surfaces area of the tubular conduit. 
     In contra distinction to the embodiment of the system illustrated in  FIGS. 4   a  to  4   d ,  5   a  and  5   b ,  6 ,  7   a  and  7   b  and  8 , sector  915  that is disconnected from the wall of the tubular conduit in order to produce opening  913 , is not used and is removed completely from the system. 
     Opening  913  might be made by a device similar to a device for forming openings as we presented in referring to  FIGS. 6 and 8 . At most, as any professional would understand, it is possible to add to the device also means for extracting (for example by vacuum) the disconnected sector  915  and removing it away from the tubular conduit. 
       FIG. 9   c  shows the installation of the liquid distributor component  934  through opening  913 . Distributor component  934  is manufactured in an embodiment such as a kind of a “piston” with a central passage  938  that is adapted by its dimensions to include in it, by pressured installation, the circumferential wall  937  of the liquid passage flow rate fixer  936 . 
     Installing distributor component  934  through opening  931 , might be done using an assembling device that would be assembled as part of the manufacturing system of the tubular conduit, for example somewhere towards the end of the production line, after the device for creating the openings at the wall of the tubular conduit (discussed when referring to  FIGS. 6 and 8 ). Any professional would understand that an assembling device as cited, dictates integration with automation and control capabilities (for example—a vibrating means for advancing the distributor components, a piston with grasping means for installing the distributor components into the sprinkler unit, timing control circuitry linked to the detecting—locating device on the production line, and due to the time consuming nature of the installing procedure—it is to be remembered that the tubular conduit is continually being pulled by the puller and advances all the time, so that the assembling device has to keep moving with it and parallel to it). 
       FIG. 9   d  shows the system  910  assembled and ready for operation, wherein the liquid distributor assembly  945  of sprinkler unit  935  is installed and ready to move through opening  913 , in a manner that upon liquid pressure increase in the tubular conduit, it would protrudes beyond the outer surface areas of the tubular conduit. 
     Any professional would understand that removing the disconnected sector  915 , as required in order to enable the completion of sprinkler unit  935  assembly in the embodiment described above, does not prevent installation of an efficient means for preventing contaminants from entering the sprinkler unit. Thus for example, the upper end of liquid distributor component  934 , the end that moves through the opening in the tubular conduit and protrudes beyond the outer surface areas of the tubular conduit, might be formed with wide edges in accordance with the dimensions of opening  913  into which it returns and converges when the liquid pressure drops in the tube. 
     It will be appreciated by persons who are skilled in the art, that the present invention is not limited by what has been particularly shown and described above. Rather, the scope of the present invention is only defined by the claims that follow.