NEW EMITTER UNIT FORMS

Abstract: The invention refers to conventional emitters with a path for the water pressure drop which consists of repeated parts of a basic prismatic form (1) which is contained within convex (1b) and concave (1a), almost cylindrical in shape surfaces, at right angles to the base (2), which converge to a perpendicular edge (3). In the regions of the convave surfaces, cylindrical craters (4) are raised from the bottom, half way along the emitter height, forming hydrocyclones. Prismatic wedge-shaped forms (5) are also developed radially from the base along half of the emitter height. As far as the self-compensating emitters are concerned, our invention refers to an arrangement for water filtering at the inlet of the emitter which consists of an elastic membrane (24) which covers peripherally the mouths of a closed cavity (33) with radially engraved channels (18) of a small depth. Self-compensation is achieved in successive stages and in several cavities (31, 33) of the path by a combination of a couple of holes for the inlet and outlet of the water into the cavities and of a membrane. The membrane (24) balances at same height above all of the cavities and water paths which are arranged in series.

Description: NEW EMITTER UNIT FORMS The present invention refers to conventional and self compensating emitters suitable either for welding inside tubes or for independent placement on the tubes. In existing systems, the flow of water in the flow restricting paths involves a motion of water in two dimensions: In the U.S. PAT. 4.215.822 the motion is between the rims of an alternately repeated triangular form. In the U.S. PAT. 4.655.397 the pressure drop and the motion is performed in the repeated vortex arrangements. In both cases motion is two - dimensional and is clearly limited on the upper and lower sides by parallel flat or coaxial circular surfaces. The disadvantage of these conventional systems was the low performance, i.e. the small pressure drop that they were achieving per unit length or step of the path. This disadvantage forced manufacturers to use long distance flow restricting paths. The usual flow restricting paths had lengths up to 100 times the basic step of the meander and were using cylindrical mainly emitter bodies for space reasons (U.S. PAT. 4.215.822 and U.S. PAT. 4.655.397). Alternatively they extended along the whole length of the tube (U.S. PAT. 4.880.167). For this reason we have developed a new form of flow restricting path of high performance and small size. In the Drawings 1-7 we will first examine our new flow restricting paths in a conventional emitter without self compensation, which is simply welded inside a tube, with a water inlet onto the emitter and a water outlet onto the tube. In our new meander-like path. Drawings 1, 2, the form consists of parts of a basic prismatic shape 1 which projects on both sides of the emitter unit 6, from its side to the main axis all along its height. The prismatic form is enclosed by concave la and convex lb almost cylindrical side surfaces, vertical to the base 2, such surfaces converging to a perpendicular edge 3 in the area of the main longitudinal axis of the emitter 6. SUBSTITUTE SHEET (Rϋt£ 26) From the base of the emitter, cylindrical craters 4 a raised which, however, terminate half way along the height the emitter. The craters 4 are developed in the regions of t concave la surfaces of the basic prismatic forms 1 which fo part of the craters. The concave surface with the crater forms hydrocyclone with an axis perpendicular to the base 2. An unlimited number of prisms is raised from the base o the emitter, such prisms having a wedge - shaped form 5 an terminating at the same height as the cylindrical craters 4. Th wedge - shaped forms 5 extend approximately radially wit reference to the edge 3 of the basic prismatic form 1, wit edges 5a with sharp edges and an edge width of 0 - 0.15 d always vertical to the said edge 3 of the basic form. One sid of the wedge - shaped forms 5 is a concave, almost cylindrica surface 5aa, with an axis parallel to the base 2 of the emitte 6, open to the side of the water inlet. All the forms of the base have a height b, Drawing la sharp edges and leave the cross section at the upper part of th emitter free, for the unobstructed flow of the water. In regio dl. Drawing 2, i.e. in the upper part of the emitter, no form other than the basic ones 1 are found. From the development o the cross sections along the total path of the water, it can b seen that the smaller cross section appears only in the region of the edges of the forms 5 of the base. All other regions hav a cross section far larger (almost double), something importan for avoiding blockages. Water inflow is via the filters 9 of the base 2, Drawing and water outflow is effected via the hole 11 opened on the tub 10, above the region 12 of the emitter 6. The flow of the water 7 in the emitter, Drawing 3 and 4 is divided before the hydrocyclone into streams 7a and 7b stream 7a follows the known hydrocyclone flow, i.e. a, helicoi stream in the beginning, descending to the base following th inner jacket of the hydrocyclone and then ascending in helicoid stream of a smaller diameter from the centre by the axis of the hydrocyclone. The intensive drop of the pressure of the water in the hydrocyclone is due exactly to the reverse motion of the helicoid ascending and descending streams of a different diameter of the stream 7a, something that is not observed in patents already known, e.g. U.S. PAT. 4.215.822 and U.S.PAT. 4.655.397. After the hydrocyclone, the water changes its direction in order to enter into the next hydrocyclone, and so on. At this phase of change of direction of the water, the large number of the radially arranged wedge - shaped forms 5 of the base interferes, the concave surface 5aa of which forces the water to form a vortex 8 with an axis of rotation horizontal and parallel to the edge 5a of each radial form 5 which causes the vortex. The axis of rotation of the vortex 8 is at right angles to the rotation angle of the hydrocyclone, with a direction reverse to the principal direction of flow 7, 7b of the upper part of the emitter, Drawing 2. This large number of horizontal vortices at the lower part of the flow, 7 and 7b creates intensive and successive contractions of the flow above all the edges of the radial forms, i.e. in the whole region of the change of the direction of the water. At the same time the part 7a of the flow, coming off the hydrocyclone creates a very intensive vortex in the area of the edge 3 with an axis of the vortex perpendicular to the base 2. In each of these perpendicular radial surfaces - cross sections which are defined by the edge 3 and the edges 5a of the prismatic forms 5, these two kinds of vortices act upon. The simultaneous influence of the two perpendicular vortices on the same cross - section, brings about a far larger flow contraction and consequently a larger total pressure drop in the emitter, compared with a situation where each vortex would act alone upon a different cross section of the flow. Tests have shown that for the efficient operation of t hydrocyclones as well as for the formation of horizont vortices, a high value of the depth b is required. Values of must be in the regions: 0.8 d > b > 0.5 d, where d: is the basic step and the distance between t edges 3 of the basic forms 1. Regarding d, dl, d2, the following must hold: dl< d< 1.3 dl; d2 ≥ d, where dl is the height and d2 the width of the path in t region of the edge 3. The pressure drop, according to our tests, depends apar from the depth b, on the number N of the radial forms 5. Fo maximum performance, in the region of change of direction of th water, and in particular 70 degrees before and after the basi edge 3, the relationships 1 < N < 6 and 1 < N for eac elementary surface d x d2 must hold. It is logical that these special forms of the bas increase the number and the intensity of the specific hydrauli resistances for each repeated part of the emitter path or pe unit length, at the same time increasing the total pressure dro in the emitter. Hence, the increase of these specifi resistances increases the performance and affects the tota pressure drop, far more that the increase of the length of th emitter itself. Additional advantages of the new emitters are: Turbulent flow is achieved even in low pressur regions and small water flow rates. The pressure drop is at least doubled for a certai length and water flow cross sectional area, giving the ne emitters higher efficiency in comparison with common emitters a those of the U.S. PAT 4.215.822 and 4.655.397. This advantage permits the manufacture of emitters of very small size, for a given cross section of the path for th water flow to the emitter, something necessary for th manufacture of modern dripline ducts with thin walls, where emitters of a big size and length tend to be easily detached or to pierce and destroy the thin walls of the tubes. The new emitter is not prone to blockages. The typical water flow cross sections d 3 xd and d x xd 2 , whereas they represent the narrowest parts, are always enclosed within two sharp edges 3 and 5, Drawing 1, at an angle of 90 degrees to each other. No foreign particle can thus stop, remain or get wedged onto these edge. Due to the contraction of the flow, velocities in this part are far higher than in other parts of the path. A particle that might enter this region, would either fall in front or behind the said cross section, in spaces of double or triple its volume, i.e. within the cellular cavities of the base with the large depth b. In these cellular spaces, vorticity has an intensity, direction and speed that will keep the particle rotating, without obstructing the flow of the water, until its dimensions are reduced because of mechanical friction and its removal become possible. As the cross section along the path is continuously varying but remains always larger (due to the additional depth b of the base) compared to any of the existing emitters, the hydraulic resistance of the total path under low water pressure conditions in the network (e.g. at the ends of the irrigation lines or during start-up) is always lower therefore the drop of pressure is lower than in existing emitters with narrower paths. On the other hand, when high pressures prevail in the network, the hydraulic resistance is far higher than in existing systems, due to the large number and the extent of the specific hydraulic resistance. As a result, the flow is comparatively higher in low network pressures and lower in high network pressures. The characteristic curve of the Discharge vs. Pressure of the emitter, is more flat and water supply more uniform. Thus, smaller deviations of water flow to the emitter are caused by large deviations of the pressure in the network. Such result is not achievable with the known emitters, to whichever extent t length of their path is increased. This enables larger lengt of dripline ducts, without intermediate supply by central duct with a significant cost reduction. In another realisation, the surface of the crater 4 of t hydrocyclone, can be open along one part, across the who height b, 4a, Drawing 3. Similarly, a smaller hydrocyclone wi crater 4c may be added opposite to the basic hydrocyclone Drawing 5. Drawings 6a, 6b illustrate an emitter with small crate and a symmetric basic prismatic form 57, consisting of flat, 5 and concave, 57a surfaces. Each of the radially extending for of the base, with straight edges 5a have a different shapin The form 5f consists of symmetrical flat surfaces with isosceles triangle cross section, the form 5e consists of fla surfaces with a right - angled triangle cross section, wherea form 5 is similar to that of Drawing 1. Drawing 6c illustrates an emitter with non - symmetrical basic prismatic forms extending to both sides, hydrocyclones o different dimensions and radially extending forms. Drawing 6 illustrates an emitter with a basic prismati form in the shape of a right - angled triangle, a smal hydrocyclone and smaller basic prismatic forms lc at the ends o the prismatic forms of the base, which can be arrange radiallly, 5b, or in another direction, 5g, or parts o prismatic forms 5d, 5e or simple raised pins 5h. The forms o the base can have curved edges, 5c. Drawing 6d illustrates an emitter with an inclination o the symmetric basic form, smaller than 90 degrees and radiall arranged forms. In general, any combination of three kind o forms, i.e. the basic prismatic form, the hydrocyclone, th radially extending forms, or of two of the above, can b manufactured. In a simplistic form, one could resemble the flo as a movement of the water on top of cavities, open or closed with sharp edges and a cavity surface of the cavity smaller tha the elementary surface d x d2 and a signifiicant depth b, where 0.8d > b > 0.5d. In another realisation of the invention (Drawing 7), the new flow restricting path could be formed as a closed cylindrical surface, with the form being developed along the external surface of the cylindrical disk 13. The meander form will be supplied by a new circular base, 14 which will bear the nozzle for water inlet to the emitter. A second external coaxial cylinder with a flat circular base, 15, which will bear the nozzle for water outlet 11 from the emitter, will cover the external part of the first cylinder which bears the path. The internal cylindrical surface of the external cylinder 15, will form the cover of the water path. These two cylinders will form the emitter. In another realisation of the invention for ON - LINE emitters, the form of the path could be engraved in the periphery of the flat surfaces of a disk similar to disk 13 of Drawing 7 (not drawn) . Such forms could be engraved either to the upper or the lower surface of this disk, with the water passing at first to the lower and then to the upper path of the disk. In another realisation of the invention for IN - LINE positioned cylindrical emitters, this form could be engraved on the outer surface of the cylindrical emitter. In this case, the internal surface of the tube would form the external surface of the water path (not drawn) . Another aspect that has not received adequate research yet is the filtering of water at the inlet of the paths, and in general at the inlet of the emitter. Systems that have been developed so far involved cylindrical holes (EPO, Al 01, 38636) whether of a polygon or rectangular shape. Such holes had constant dimensions, with one dimension normally smaller than the narrowest dimension of the water paths in the emitter, e.g. f<d. Drawing 1. Also, the emitters described in U.S. PAT 4,147,307, U.S. PAT. 4.344.576, EPO Al 0006,755, U.S. PAT. 4.382.549 that could be considered have some filtering capabilities, what they really possess flashing out capabilities, as during the water suppl compensation they just increase or decrease the dimensions o the narrow cross section of the water flow, only after the wate with the foreign particles has entered into the emitter. In our new self compensating emitter the water is filtere upon inlet by an elastic membrane which cover and encircles th sharp edges of a closed cavity. On the cavity edges, shallo radial channels or wedge shaped protrusions which form wide an shallow channels between them are engraved. In the centre of th cavity a hole exists, wherefrom the water passes to a flo restricting path before it is discharged to the atmosphere. The water enters from the shallow channels of the shar edges under the membrane which moves and bends continuously ove the cavity due to the pressure difference between its upper an lower surface. The geometry, as well as the synergy between the cavit and the moving membrane, causes them to move continuousl relative to each other, in a manner that the membrane wil always push the foreign particles which accumulate in th periphery of the cavity or on the membrane itself, removing the from the emitter. In Drawings 8 - 11, a self compensating emitter of ou invention is described, such emitter being suitable fo attachment to the inner part of a tube. The body of the emitter 16 bears a closed, almos spherical cavity (17) with sharp edges (17a) and shallo channels engraved radially (18) along the whole internal surfac of the cavity, whereas a membrane (24) just covers the edge (17a) of the cavity. At the centre of the cavity 17, a hole 1 with a rim 19a is located. The water enters from the shallo channels 18 into the cavity wherefrom it passes via the hole 1 towards the meander path 20, and from there via the chamber 2 and the hole 22 of the tube 23, it is discharged to the atmosphere. The internal surface 17b of the cavity and the cylindrical side surface 24a of the membrane 24 constitute the filter of the emitter. Drawings 8a - 8c describe the self compensating operation of the flow and the self - cleaning features of this filter. The water inlet via the shallow channels 18 under the membrane creates reduce pressure conditions depending on the extent of which the membrane 24 is bent and assumes every time a fully defined position with a distance xl relative to the rim 19a, so that the flow through the emitter remains constant. In higher pressures, the membrane enters into the small cavities of the channels 18, reducing even further the water supply. If in the particular operating position, a compact ring of foreign particles 25 concentrates around the whole surface 24a or part thereof, the filter will close completely and the flow of water towards the open flow restricting path 20 will be interrupted. Due to the above event, the pressure in the cavity 17 will be reduced further with the result that the membrane 24 moves nearer to the rim 19a of the hole 19, position x2. Drawing 8b, where x2<xl. At the same time, the side surface 24a of the membrane 24 is displaced from the ring 25, the flow in the flow restricting path is resumed by the new void created and the membrane returns to the position xl, and so on. This continue interchange between positions xl and x2, destroys or disturbs the cohesion of the compact ring of foreign particles 25, such ring eventually being removed completely from the emitter, each time that the irrigation phase is interrupted, completed or repeated, as the membrane returns then to its original horizontal position. Drawing 8c and scrapes automatically the foreign particles. In general, we observe that a relative motion exists between the side surface 24a of the membrane and the internal surface 17b of the cavity, this motion contributing to the mechanical removal of foreign particles and the self - cleani of the filter. For each value of the internal pressure PE of t water in the tube 23, the membrane 24, and in particular it surface 24a reaches a different peripheral contour line passin from the points A, B, etc. In the variation of Drawing 8d, the membrane 24 has bigger dimension A, and covers the cavity. In this case, th relative motion scrapes the ring of foreign particles 2 immediately from the membrane itself and the emitter. Experimental application has shown that best results ar achieved when the following relationships hold: d < a 3 Dl < D2 < 10 Dl where d is the thickness of the membrane 24, a is th distance of it from the rim 19a, D the diameter of the hole 19 D2 the diameter of the membrane. In Drawings 10a - 10b - 10c another variation i described, where the cavity 17 could have an oval form fo increasing the length of its perimeter and the surface of th filter. In the same variation the hole 19 is eccentric an peripheral, closed protruding contours appear in the interna surface of the cavity, which actually constitute successiv contact positions of the membrane with the cavity, during th sequential descent of the membrane during the phase of sel compensation of the water flow to the emitter. The motion of the water, in the beginning, in the shallo channels creates a pressure reduction and the membrane starts t descend towards the contours 26a, 26b. As the contour 26a, i already distant from the base by a length Xa, the velocity o water is higher in the void between the edge of the contour an the membrane, resulting in pulling the membrane and lowering i into the periphery of the cavity 17. The membrane is als lowered between the spaces between two successive protrudin contours as well. The phenomenon is understood by comparing th positions 24b and 24c. Position 24c corresponds to a variatio of a flat base 27. This additional lowering is due to the fact that the pressure in this case is not the same at all points under the membrane, as it happens in a flat base variation 27, but is gradually reduced from one contour to another. The same pressure applies only along all the whole peripheral void, between two successive contours. The advantage of the contours is the increase of the relative motion between the edges 17b and the surface 24a for better scraping of foreign particles. Another advantage (apart from proper filtering) is the ability to maintain steady water flow in the emitter for all water pressures in the tube, in a far more efficient manner, as the compensation of the void spaces in the water inlet is gradual, in a larger number of far bigger surfaces and points and with a smaller pressure difference from one surface to another. In existing flow compensating systems with a flat and smooth base 27, U.S. PAT. 4.307.841, the compensation of the flow is exclusively performed on the rim 19a of the outlet hole and with a far higher pressure difference before and after the rim 19a. Finally, the positioning of the filtering system before the flow restricting path 20 of Drawing 8, has the advantage that due to the permanent throttling of the water in the shallow channels 18, even in the beginning of the operation of the emitter, i.e. in the flushing out phase, the usual sudden increase of water discharge (which can lead to a doubling of the latter) is avoided, prior to the activation of the membrane. The phenomenon of this sudden increase of the discharge in the start - up of the operation, causes the known significant problems originated by a prolonged non-uniformity of the outlet of the emitters, as the supply of the networks and the pumps is not sufficient for such a momentary increase. For this reason the meander 20 can be omitted without causing a problem of a sudden increase of the discharge; the hole 19 then discharges directly to the atmosphere. Should the meander remain in place, there is a possibility to increase cross section area considerably in order to avoid all block problems, as the pressure drop in the filter has alre decreased the velocity of the water. As the biggest prob associates with blockages is caused just by this conventio flow restricting path 20, emitters of exceptionally sm discharge could be manufactured, with a spacious fl restricting path, or even without one. Drawings 8e and 8f illustrate two variations of t membrane 24. In one of these variations, the membrane bea radial cuts; in the other it is thinner in its periphery. Bo variations facilitate a more intense bending in the periphery the membrane, with an increase of the relative movement of t membrane and the emitter. In another variation the filter system terminates to straight line instead of a periphery of a circle. In another variation, Drawings lOd - lOf, the filteri space f is considerably more spacious. In the place of t external perimetric edges 17a, Drawing 8, the arms 28 are fitt which support the membrane 24, whereas the cavity 17 essential is substituted by the perimetric contour protrusion 26a at considerable distance f from the membrane 24. Reduced pressu is created by the motion of the water through the void space the extent of this pressure reduction regulating the operati positions of the membrane, 24e, 24f etc. which is supported a slides on the internal surface 28a of the arms 28. As in t first variation of Drawings 8 - 9, filtering occurs along wi water supply compensation, as the distance xl. Drawing lO between the membrane and the rim of the hole 19, is reduced the pressure in the tube increases. The position and the size of the ring 25 of the forei particles is also compensated by the operating position. As t relationship f « Dl, always holds, during the return of t membrane to the original position 24d, the foreign particl pass easily, even through the outlet hole Dl. For better performance, the relationship: 3<D2/D1<10 must always hold. In another variation, the contours (26a, etc.) can be altogether omitted and the cavity 17 can be flat. Drawing lOg illustrates a variation, where the membrane 24 is not flat but essentially has the form of the cavity 17 of Drawing 8, with the rim 19a, the contours 26a, 26b and the arms 28, radially arranged so that the periphery of the void space f is defined. Furthermore, the arms 28, as well as the contours can be omitted and a large number of small shallow radially extending channels be found in their place. Such channels can be saw-shaped or have a different cross section. They extend along the whole length of the edge along which the membrane comes into contact with the emitter. Drawings lOh, lOi, 10k, 101, illustrate another variation of a filter. The minimum width slots 41, divide the elastomeric shell 24 into bands of an alternating small (42) and large (42a) thickness. With the water pressure, the bands 42 are pushed further than the bands 42a, thus creating a relative motion of the bands 42 and 42a, perpendicular to the base, along the whole length of the slots 41, which does not influence the width of the slots. In any interruption of the irrigation process, the bands 42 return, scraping the foreign material from the slots 41. In the Drawing lOi the slots 41 are parts of circles. In another variation the bands may have the same thickness but be free (as a projecting beam) at one end for higher flexibility. Similar bands can also exist in flat membranes. Also, in another variation it is possible that after the compensation of the discharge performed by the filter, another cavity with a hole is present as well, after the flow restricting meander - like path 20, where the final compensation of the water supply is performed by the membrane itself (not drawn) . It is also obvious that a dynamic filter with a moving membrane can operate only as an inlet filter of the water without a significant pressure drop, and that another system f the final compensation of the water supply using the sa membrane, is fitted after the flow restricting meander - li path to assure the stability of the water supply. It is al possible that the flow restricting path is absent and that bo the filtering and the compensation of the supply are on performed in the cavity 17 (not drawn) . It is also possible th the membrane operates in only two positions. Drawings 10m, lOn illustrate a variation where the fl restricting meander - like path 20 exist at the base of t cavity 17. In this case, the small channels at the edges of t contour protrusion 26b are more concentrated in the beginning the path 20. The filtering is performed in the whole periphe of the emitter, whereas the constant supply is assured both i the contours or the inlet of the cavity 21, and/or the rim 19. Techniques known so far for compensating the wate flowrate in the emitter use one single cavity, with one outle hole and one rim on top of which a membrane moves (e.g. U.S.PAT 4.307.841). A determined position - distance of the membrane from th rim of the inlet hole corresponds to every value of the pressur of the water in the tube. An essential disadvantage of the techniques already know is that for pressures larger than a particular pressure in th tube, the membrane touches completely the rim of the outle hole. For even larger pressures the motion of the water i continued only via some small channel existing on the rim of th hole. The cross section of the flow in these pressure regions i far smaller than the hole of any conventional filter and th flow in the small channel is continuously interrupted, resultin in very non-uniform discharge. Given as well the value of the maximum balance depth o the membrane, the accuracy and the sensitivity of th compensation depends on the size of the maximum pressure in th tube, for which the operation of the emitter has been programme and is recommended. According to the above, the sensitivity of known systems is very small, as they only use one cavity with one hole, whereas a high operating pressure corresponds to a given width of the maximum balance depth of the membrane. For this reason the operation of these emitter for high mains pressure or heavily inclined grounds is not recommended. In the Drawings 12 - 21 we will examine a new variation of a self compensating emitter, where after the water inlet filter, a new procedure for the compensation of the water supply is performed. The compensation process is performed in successive stages and in various positions of the path. The compensation is also connected with a successive and very intensive drop of the water pressure and has as a result the increase of the cross sections, the improvement of quality of compensation , the increase of the sensitivity of the compensation and the ability to use the emitters at high pressures or highly inclined grounds. The membrane 24 in the new emitter has been extended and covers two new cavities 31 and 33 which bear two holes 29, 29a and 30, 30a of the same diameter, symmetric and placed very close to each other with common rims 29b and 30b, respectively. The water passes successively from the filter 17a, the hole 19, the spaces 61 and 31, the holes 29, 29a, the spaces 32 and 33, the holes 30, 30a, the space 34 and from there it is discharged to the atmosphere via the hole 22 of the tube 23. In Drawing 16 we will first examine the behaviour of water in one of the cavities with the 2 holes and the membrane and will assume that the membrane 24 balances at a distance x from the common rim 29b of the holes 29, 29a under the influence of the pressures PE in the tube and P3 in the space 61. As the holes have the same diameter, Dl, they are located very close to each other and for each value of the pressure in the tube they are at the same distance x from the membrane. The pressure P3 of the space 61 is subject, due to frictions on the common rim 29b, two successive and equal pressure drops, one at the hole 29 at the entrance to the cavity 31, ΔH3 = P3-P4 and one at the ho 29a at the outlet from the cavity 31, ΔH4=P4-P5=ΔH3. The total pressure drop in a single space, i.e. the cavi 31, ΔH3+ΔH4 = 2ΔH4 = P3-P5=2ΔH3 is exactly double in comparis with the respective pressure drop in a cavity of existi technologies which use a single active hole, the outlet hol i.e. U.S. PAT. 4.307.841. Another significant difference betwe the new and the known technologies lies in the fact that as t pressures in the cavities are far smaller than the pressure in the tube due to successive throttling in the water, t membrane is bent along the whole surface of the cavity, Drawin 16-16a, even at the periphery, at not only at a point above t hole, as illustrated in the curve 24N, Drawing 16a; as a result the pressure drop and the efficiency in general are far higher. As, however, the pressure PE in the tube is constant at particular time, whereas the pressures in the respecti cavities 31, 33, etc. are different at the same time in each o the cavities, the membrane 24 is bent at a different depth o top of the group of two rims of each cavity if the cavities ha the same dimensions. This problem can be overcome with th progressive reduction of the dimensions LI, Wl to L2, W2, etc keeping however, the width or the depth a constant in th cavities. Thus, we achieve the same degree of bending an consequently the same distance x of the membrane simultaneousl above all the groups of double rims, 29b, 30b, etc. A simila result is achieved with the progressive increase of th thickness of the membrane. Drawings 16a, 16b also illustrate a specific arranged an elevated common rim 29c, with an internal diameter W3, aiming t achieve (with the second bending in the internal part of th rim) , the same distance x of the membrane 24 in the case wher the cavities 31, 33, etc. have the same dimensions L, W. In another variation the depth of the cavities i gradually increasing, as we advance towards the outlet, so tha the membrane keeps always during the operation the same distance from all the rims of the cavities (not drawn) . With the unified behaviour of the membrane 24 above all the rims and due to the fact that the throttling of the water is performed at many points - holes simultaneously, a far larger distance from the common rim x is arised in comparison with the existing known systems with one cavity and one hole, in order to achieve a particular pressure drop and consequently a given constant water flow rate. This larger distance x limits the danger of blockages and the number of holes increases the effectiveness of the emitter path. As, due to the large number of cavities, for a given maximum value a, Drawing 12, of the membrane bending depth, the maximum pressure differences PE - P4 etc., in the different cavities 31, 33, etc. which determine every time the positions of the membranes are far smaller compared with the known systems which use a single hole cavity, the sensitivity, the quality and the reliability of the compensation in the new invention is better. Another advantage of our new invention is the fact that the distribution of velocities along the perimeter or periphery of the holes 29, 29a is not symmetrical and uniform, as in the known systems, but the velocities are far higher in these parts where one periphery or perimeter approaches the other. This phenomenon permits us to increase considerably the length of the periphery or of the perimeter, and consequently the cross section of all these holes, without increasing to the same extent the water flow in the emitter. By arranging a large number of cavities with double holes in the emitter, we can achieve a fully controlled pressure drop, several times higher of that achieved by the known systems. In addition, we can increase several times the maximum recommended working pressure of the emitter which consequently will increase the maximum recomended lateral length of the irrigation tubes, i.e. the tubes upon which the emitters are positioned, with a significant reduction of the number of central water supp tubes in the irrigation systems. This leads to a respecti reduction of the cost of such systems. As due to the gradual, uniform and very large increase the pressure drop along the flow the velocity of the water the emitter is reduced to the minimum possible, our syst permits (for a given water supply) to design cross sections holes and in general paths in the emitter with a surface ar several times larger than that of known systems. This has as result the minimisation of the risks of blockage which present constitute the most severe problem and render the use o expensive filters necessary. We also have the capability, shoul the flow from the hole 22 be interrupted by a blockage to open second or third hole in the tube above the cavities 61 or 3 reinstating the operation of the emitter. In the Drawing 15a the cavity 61 bears a path 62, as well. Our new invention also permits for the first time th production of emitters with extremely low water supply, but wit spacious holes and water paths, which will further increase th maximum recommended lateral length of irrigation tubes Furthermore, the fact that meander - like flow restricting path are absent, the cost of construction of the emitter i significantly lower. Drawing 16c illustrates a variation, where the two rim have a different height ΔX. In this case the membrane 24 canno be bent uniformly above the rims, and the pressure difference occurring are different. If the rim of the inlet hole 29 i higher than the rim of the outlet hole 29a, then : P3 - P4 > P - P5. On the contrary if the rim of the hole 29a is higher then P3 - P4 < P4 - P5 (not drown) . It is also possible that the ri of the hole 29a is so high that the membrane does never touc the rim 29. In this case P3 is equal to P4 and the rim 29 doe not influence the compensation, of the water discharge. In the Drawings 17 - 17b, a variation is illustrated wit 4 holes, two for input to the space 31 (29, 29d) and two fo output from the same space, 29a, 29e. Both the inlet and outlet holes have a considerable difference in the height of the rims AX. The holes 29 and 29a bear a tiny channel 29f and 29g which is directed towards the holes 29d and 29e respectively. Water from the space 61 enters into the space 31, at the beginning simultaneously from both holes 29 and 29d. Immediately after the beginning of the operation, the membrane 24 covers both the so vigoroys raised rim 29 and its small channel 29f completely. Both the flow and the compensation of the supply is now performed only via the hole 29d which is called main inlet hole. A similar phenomenon occurs with the outlet holes 29a, 29e as well, where the hole 29a closes and the flow is maintained only via the hole 29e which is called main water outlet hole. As soon as the main water inlet hole 29d is completely closed following accumulation of foreign particles and flow through it is interrupted, the membrane is raised immediately over its rim 29d and unveils the tiny channel 29f. Both the flow and the compensation of the water supply in this region is performed solely by the auxiliary hole 29 and its tiny channel 29f. Of course, as the flow is for any reason re-established in the main hole 29d, the flow in the auxiliary hole 29 is interrupted by the membrane, so that it is only conducted via the main hole 29d. A similar operation can be performed with the outlet holes, with the hole 29e being the principal one and the hole 29a being the auxiliary one. Obviously, the holes can be more than four, divided in an inlet and an outlet group and with a different rim height for each hole of the same group. Apart from the existence of many auxilliary holes, this renders the procedure of pressure drop more easy, and subsequently of the compensation of the water supply. Drawing 18 illustrates that the application of the principal and auxiliary hole can be expanded to the known technologies with one cavity and one outlet hole (U.S. PAT 4.307.841), by hole an auxiliary hole 29a into the cavity and next to the main hole 29e. Both in this case the rim of th auxiliary hole must be far higher than the rim of the principa hole 29e. As, however, in this case a meander - like flo restricting path 35 exists, and as the blockage is more likel to occur in the path 35, rather than the hole 29e, a space ca be created for hole an additional auxiliary hole 29h at som point along the path, with the same geometrical characteristic of height, tiny channel, etc. as in the case of the othe auxiliary hole 29a. In the same manner, the phenomenon can b applied to known, simpler technologies, where the flo restricting meander - like path 35 is absent and where only th mainly compensating cavity 31 with the outlet hole 29e exist. I these cases it is obviously enough to open an auxiliary hole 29 (not drawn) . The auxiliary holes in general double the life o the emitter which is rendered useless in principle, due to th large problem associated with the blockages. This can also b applied to the cylindrical emitters WO 93/02547 and E.P A 018088. Drawings 19 - 19a illustrate a different variation, wher the cavities are continuous and holes 19, 29, 29a, 30, 30a i the spaces 17, 31, 33 of the emitter of the Drawings 12, 13, 14 15 are replaced here by channels which are formed between tw prismatic forms with inclined edges. The edges 36, 37 of th channels 29, 29a of the cavity 31 correspond as far as thi matter is concerned to the characteristic pair of holes 29, 29 of the emitter of the Drawings 12, 13, 14, 15. The length of th cavities LI, L2 gradually decreased as we advance towards th oytlet 22 of the water. The membrane 24 is bent alternately during the operatio above all the inclined inlet and outlet edges, as it appears b the broken curve 39. The distance of the membrane X from th base is equal for all the cavities. All other matters th filtering as well as the compensation of the discharge are th same with the case of the emitter of the Drawings 12, 13, 14, 15. The same holds in this case generally as per the case of the cavity with two inlet - outlet holes. In another variation (not drawn) the membrane 24 is completely omitted but all the rest emitter 16 is built from one and only piece from elastomeric material and is inversely attached on the tube 23, with the cavities 31, 33 towards the internal surface of the tube 23. The compensation of the discharge is performed between the edges of the channels and the internal surface of the tube 23. Drawings 20 - 20a illustrate another variation with two independent membranes 24c, 24d, where the holes are replaced again by channels 19, 29, 29a, 30, 30a with inclined edges 19a, 36, 37, 38, 38a, but both the filtering of the cavity 17 as well as the compensation of the supply in the cavities 31, 33 are performed simultaneously from two sides of the emitter 16. The body of the emitter 16 is attached internally in the duct by the edges of the cavity 34. It is obvious that one single elastic tube could be in place of the two independent flat membranes which could cover the emitter. In another variation the whole emitter 16 with the membranes 24c, 24d could be made from one single piece of elastomeric material (not drawn) . In the sequel, we will describe a new variation where the emitter is cylindrical and consists of one single piece of elastomeric material. The known systems of cylindrical emitters made by elastomeric materials, WO 93/02547, EP.A.O. 018.088 and EP.A. 0295.400 have the same disadvantages as the known system of the U.S. PAT. 4.307.81 already described. In the Drawings 21, 21a, 21b, 21c, 21d, we will describe the new emitter the differences of which relative to the emitter of Drawings 19, 19a consist in that the cavities 17, 31, 33, 34 are cylindrical, as the water inlet filter as well. The emitter is solidly attached to the internal part of the tube 23 with the cylindrical surfaces 39a, 39b, 39c, 39d. The rims 19a, 36, 37, 38, 38a, 38b of the water inlet - outlet holes to the chambers are inclined and flat, and the lengths of the cavities LI, L L3 are gradually decreased as we advance towards the wat outlet 22. The meander - like flow restricting paths in t spaces between the cavities are not necessary, (but they may exist) as the water pressure is intensively throttled during t passage of the water through the in - series arranged cavities The water inlet is performed along the perimeter of t cylindrical surface of the filter. During the inlet of the wat from the filter, reduced pressure in the space 17 forces t surface of the cavity 17 to move towards the inner surface the tube 23, limiting the void between the blades 40 and t internal surface of the tube. The reduced pressure in the cylindrical spaces 31, 33, causes bending of the walls of the emitter relative to the tu and the pairs of rims 36, 37, etc. approach together to t inner surface of the tube. The pressure drop of the water gradual from one cavity to another and the bending of the wal is the same, x, in every cavity, due to the progressi reduction of the length LI, L2, L3. In this case, the same hol as for the emitters of Drawings 12, 13, 14, 15 and the variations. In another variation, the relative positions of t channels 19 - 29 and 29a - 30 are displaced on the periphery that they are not placed on a straight line. In another variation the thickness of the wall, ΔW gradually increased from the cavity 31 until the cavity 34. In another variation, the filter occupies only one part the periphery of the emitter. In the Drawing 21c, a filter is illustrated similar that of Drawings 10h, 10i, 10k. The two rims 39, 39a of t cavity 17 of the filter are permanently attached onto the tu and the jacket bears narrow longitudinal slots 41 which separa the jacket into alternate thin bands of a small and a lar thickness, 42 and 42a respectively. In another variation, Drawing 2Id, the slots 41 are perpendicular to the axis of the emitter, with the only difference that the bands 42a are supported with protrusions 42b onto the tube, whereas the bands 42 are left free for greater mobility. A relative motion is established between the bands 42 and 42a and along the slots 41. It is obvious that in the inventions of the Drawings 12 - 21, it is not necessary that the distance X of the membrane is the same above all the rims of the cavities. Drawings 22, 22a illustrate a new variation which further improves the sensitivity of the compensation of the water discharge, also increasing the range of pressures of operation and application of the emitter. The emitter is positioned onto the tube 23 with the nozzle 43. At the inlet of the emitter, at the end of the hole 19, of a diameter Dl, the flat circular surface 19c with a diameter D2 and the acute rim 19c are formed and are fully covered by the membrane 24. The consecutive cavities 17, 31, 33 with the characteristic pairs of holes - channels - rims 19d - 19a, 36-37 and 38-30d in the cavities 17, 31 and 33 respectively are also present. Despite the fact that the rims 38-30d in the space 33 are of a different geometry, one rim belonging to a channel and the other to a hole, the two rims behave as a couple as they are simultaneously covered by the same membrane. The water enters via the hole 19, passes under the rim 19d into the space 17, via the channel 29 into the space 31, via the channel 29a and 30 into the space 33 and via the hole 30a to the atmosphere. During its passage between the membrane 24 and the rim 19d of the hole 19, creates the known, due to the velocity difference in the peripheries Dl and D2 vacuum, which pulls the membrane 24 onto the surface 19c and the rim 19d. The acute rim 19d increase the velocity difference further. A pressure drop of the water occurs on the surface 19c and the rim 19d, from a level PE inside the tube to a level PI in the cavities 17 and 45. As the pressure PI is increased and decreased alwa proportionally to the change of the pressure PE in the tube 2 it is not possible to maintain a constant water flow to t emitter just by the energy of the rim 19d. For this reason it important that the successive cavities 31, 33, etc., a arranged in the sequel. The water after the cavity 17 follows almost the sa process, as described for the emitter of the Drawing 19, 19a a the compensation of the flow is performed by the characterist couples of rims of each cavity. The water pressure is th reduced in a succession, becoming P2 in the cavity 31, and P3 the cavity 33. The characteristic difference of this variation of t emitter lies in the fact that the pressure prevailing in t rear part of the membrane in the space 45, is no more the wat pressure PE prevailing in the tube 23, but the far low pressure PI of the space 17, as this is established immediate after its throttling onto the rim 19d. In the other part of the membrane 24, in the cavitie pressures P2, P3 prevail, as these pressures are establish after the successive pressure drop on the couples of rims, The bending of the membrane to the position 39 and t distance x from the rims of the channels is proportional to t pressure differences P1-P2 and P1-P3, which in this case are f smaller than the differences PE-P2 and PE-P3, as in the case the emitter of Drawings 12, 13, 14 or Drawing 19, 19a. For given maximum width a of the path of the membrane t sensitivity and the accuracy of the compensation of the supp is far larger. In parallel, it must be stressed that the moti of the water under the membrane 24 in the area of the rim 1 and the surface 19c and the attraction that it causes to i functions as a filter and protects the emitter from the entran of foreign particles. Other advantages are: a) the pressure to the body of t emitter is smaller than the pressure in the tube wi significant economies in the thickness of the walls and the quality of materials; b) the maximum operating pressure of the emitter is increased unlimited along with the maximum effective length of the irrigation lines; c) the membranes are stressed by lower pressures or do not touch the rims at all. Thus, simple synthetic elastomeric materials are used with recycle properties instead of complex silicone compounds; d) absolute control of the forces acting onto the membranes is possible. For improved performance, the following relation must hold: D2/D1 > 2, without this though be binding. In another variation, Drawing 23, 23a, the pressure in the rear part of the membrane 24 is further reduced by the separation of the space 45 of the Drawing 22, 22a into two distinct and separated cavities 45, 45a, where a pressure PI prevails in the first cavity and a pressure P2 prevails in the second. Water passes from the space 31, where P2 prevails to a new space 48, and then via the hole 49 to the space 45b behind the membrane carrying along the pressure P2. Thus, in the membrane, above the final cavity 33, even smaller pressures are enacted, P2-P3. The new membrane 24 is illustrated in the Drawing 23a. Drawing 24 illustrates a new variation where a meander path 31 exists in the cavity 17 before the chamber 33 which is also covered by the membrane. The final compensation of he supply is performed in the chamber 33, onto the couple of the rims 38 and 30d. In another variation, the membrane can avoid coming into contact with the rim 38 of the channel and the compensation can be performed only on the rim 30d, or the acute rim 19d can be absent altogether. In a simpler variation of Drawing 24, the membrane can just cover the rim 19c and to leave both the meander path and the chamber 33 uncovered (not drawn) . In other variations, the meander path can exist between or after the flow compensating cavities 31 or 33, at the end of the emitter. Both the membrane and the surface 19c can be non-flat, but spherical, the one being convex and the other concave. In the Drawings 25, 25a a variation of an emitter illustrated. This emitter is suitable for positioning onto tube with two independent membranes 24d and 24e. The fir membrane 24d causes the pressure drop from PE to PI, whereas t second 24e functions on top of an outlet cavity 33 with a coup of holes and rims, 30, 30b - 30a, 30d. In another variation the cavity 33 can be flat and on bear the hole 30a. It can also feature the channel 30, the ho 30a but the rims 30b be non -active (not drawn) Drawing 25b illustrates another variation with a membra from one single part. In other variation a single membrane m exist and be horizontal, one part of it with its lower surfa covering the inlet rim and the rest with its upper surfa covering the compensating cavities or the flow compensati paths. In other variations, the membranes 24d and 24e may cov more than one cavities or meander - like paths in the emitt (not drawn) . Drawing 25c illustrates a new form of a filter at t inlet of the emitter of Drawing 25. In the centre of t membrane 24e which operates with the same manner as the membra 24d, a piston 54 is fitted, at the end of which a flexible di 55 with peripheral slots is fitted as well. The disk is made the same material with the membrane. The water enters throu the slots of the disk 55, initially lifts the membrane 24e by and then pulls it onto the rim. In this time disk 55 performs movement by ΔA relative to the surface 57 and removes t foreign particles. The system of Drawing 25d operates in similar manner with the only difference that in this case exploit the motion of the membrane 24f into the compensati cavity. The membranes 24e, 24f bear blades 56 for managing small revolution during the phases of position changing, and t number of the disks 55 can be increased. Furthermore, the pist 54 can bear guides for its appropriate displacement. It stressed that the disk 55 is efficient even if there is movement relative to the the surface 57 or to the inlet hole of the emitter. It is stressed that the filter systems of Drawings 8 - 11 can be used to attached emitters as well (not drawn) . Drawings 26, 26a illustrates a variation of the emitter of the Drawings 22, 22a suitable for internal attachment to a tube. The water enters from a large number of holes 19 under the membrane 24 into the large flat rim 19c, where the first pressure drop of the water of the tube from the value PE to a value PI in the space 17 and at the beginning of the path 31. The special, non circular, arrangement of the rim 19c and the number of holes 19, is the principal differentiation of the emitter of this variation. From the flow restricting path 31, the water with a pressure P2 is driven to the cavity 33 with the couple of rims 38-30d and the pressure P3 for the final compensation of the discharge of he emitter. The water discharge to the atmosphere, PA, is performed via the spaces 50 and 51a. In another variation the rim 38 of the cavity 33 can be inactive and the final compensation is performed only on the rim 30d. Drawings 26b, 26c illustrate another variation where the pressure PE, while reduced to PI in the space 17, remains unchanged in the space 45 behind the membrane. Both the variation of the Drawings 26, 26a and of the Drawings 26b, 26c can on the same operation principle be manufactured with the membrane approaching the axis of the tube 23, rather than the inner surface. Drawings 27, 27a illustrate another variation. The membrane 24 is located near the axis of the tube 23 and is covered by a tight cover 52. The water with a pressure PE, passing through the filter 9 into the space 17, is subject to intensive throttling on the rim of the hole 19, and the pressure PI is transferred to the space 45 between the cover 52 and the membrane 24. The water supply remains constant with the compensation onto the rim of the hole 30 and the meander - li flow restricting path 31. We have extensively discussed the greater sensitivity flow compensation and the enhanced protection of the emitt from blockages and the efficiency of the water path achiev when the membrane is equidistant from all cavities and holes. Our next patent relates to the development of speci meander - like flow restricting paths on top of which t membrane balances at the same level along the whole length the path. Drawing 28, 28a, 28b illustrate an emitter 16 suitable f attachment to the inner part of the tube, characterised by th the prismatic forms 31a of the path 31 are grooved onto concave cylindrical surface 16b with an axis parallel to t axis of the emitter, and that the thickness of the membrane is gradually increased towards the outlet of the emitter. T water enters via the filters 9, passes through the path 31 a is directed via the hole 30 outside the tube 23. The vacu created exerts a force onto the membrane 24 and lowers i towards the cylindrical surface 16b of the prismatic forms 31 of the path 31, with a smaller intensity at the beginning, bu then gradually increased to a maximum at the end of the path. For this reason the thickness of the membrane 24 graduall increases, so that the membrane - broken line 39- has the sa distance f from the base 16c of the path 31. Drawing 28 illustrates a cut of the position 39 of the membrane for particular pressure PE in the tube. We get the same resul instead of gradyally increasing the thikness of the membran when we gradually increase the depth a of the base of the wate path (not drown) . Drawings 29 - 29e illustrate another variation where th perpendicular sides 53 of the path 31 are not parallel bu converge towards the water outlet, the surfaces of the prismati forms 31a, 31b, 31c form the surface of an almost conica surface with a generating line almost touching the bottom of th path 31, and two other generating lines passing from the points Al, BI, Cl. The membrane 24 always has the same thickness. With the gradual decrease of the width of the holes LI, L2, L3, etc., the distance f of the membrane during the operation phase 39, is constant along the length of the emitter. Drawings 29a, 29b, 29c illustrate the cross sections of the emitter at the points Al, BI, Cl with the respective cuts 39a, 39b, 39c of the membrane 24 for a particular pressure PE in the tube. Drawing 29e illustrates again all the successive cuts 39a, 39b, 39c of the membrane for the same specific pressure PE. Drawings 30 - 30b illustrate a variation where the membrane has the same thickness and the vertical surfaces 53 of the path which are characterised by the points Al, BI, Cl are parallel, but with a depth which is gradually increased as we are advancing to the outlet 30. The top surfaces of the prismatic forms 31a, 31b, 31c along with the part 16b of the surface 16a of the emitter, consist the surface of an almost conical surface with a generating line being attached to the base 16c of the path 31, the base towards the inlet point and the top of the cone towards the outlet of the emitter, and two generating lines passing from the points A, B, C, outside the path 31. The differentiation of the width LI, L2, L3 of the holes causes the membrane to be at the same distance f from the base 16c during the operation phase. Drawing 30b illustrates the cuts al, a2, a3 of the cone of the path 31 at the points A, Al-B, Bl-C, Cl with the respective widths of the holes. Drawing 30c illustrates the positions of the membrane at the points of the cuts A, Al-B, Bl-C, Cl for a particular pressure PΞ in the tube. It is obvious that the particular meander - like form 31 which has been chosen is totally indicative and does not restrict the invention. In another variation, the generating lines A, B, C, of the cone pass through the meander - like path 31 (not drawn) . In the variations of Drawings 28-30c, before the princip paths of the concave surface 31, a simple meander - like pa could be manufactured, with a flat upper surface, though, whi is covered by the membrane, so that an initial water pressu drop under the membrane is created, before the principal conca path. The emitters of the Drawings 28-30 could be manufactur also by elastomeric material and consist of a single part. this case the membrane is totally absent and the emitters a attached with the surface 16a directly onto the tube (n drawn) . It is also obvious that all the emitters of the prese invention (Drawings 1 - 30c), even if they are not referre specifically, can be manufactured, altogether, with elastomeri instead of thermoplastic materials, so that the membranes ar reinstated. They are also manufactured in a shape suitable fo positioning both onto the tube and into the tube. They can als form part of a cylindrical emitter body suitable for positionin into the tube. Furthermore, wherever membranes are present these can be located either near the surface of the tube or th axis of the tube, or they may be non-flat. DESCRIPTION OF THE DRAWINGS Drawing 1 Plan view of a conventional emitter with hydrocyclone and prismatic radial forms. Drawing la Cut XI - Xl of the emitter of Drawing 1. Drawing 2 Part of a longitudinal cut X-X of the emitter of Drawing 1 Drawing 3 Schematic representation of principal elements of the emitter of Drawing 1 with one part of the crater open. Drawing 4 Schematic cut of the principal elements of the hydrocyclone of the emitter of Dr. 1. Drawing 5 Plan view of a conventional emitter with additional hydrocyclone and prismatic radial forms Drawing 6 Plan view of a conventional emitter with various forms and arrangements of hydrocyclones and prismatic forms. Drawing 6a Plan view of a conventional emitter with a smaller hydrocyclone, a symmetric basic prismatic form and three different prismatic forms of its base. Drawing 6b Cut X-X of the emitter of Drawing 6a. Drawing 6c Plan view of a conventional emitter with non - symmetric basic prismatic forms and hydrocyclones of different dimensions. Drawing 6d Plan view of a conventional emitter with an inclination of the symmetric basic prismatic form smaller than 90 degrees. Drawing 7 Conventional emitter suitable for ON_LINE positioning Drawing 8 A cut of a self compensating emitter with an inlet filter. Drawing 8a Detail of the operation of the filter of the emitter of Drawing 8. Drawing 8b Detail of the filter of the emitter of Drawing 8 in the phase of full blockage. Drawing 8c Detail of the filter of the emitter of Drawing 8 in the phase of the return of the membrane its original position Drawing 8d Detail of the filter of the emitter of Drawing 8 with a membrane of larger dimensions. Drawing 8e Variation of the membrane of the filter of the emitter of Drawing 8 with radial slots in the periphery. Drawing 8f Variation of the membrane of the filter of the emitter of Drawing 8 with a thinner wall in t periphery. Drawing 9 A view of the emitter of Drawing 8, without a membrane and cover. Drawing 10.A cut of the emitter of Drawing 8. Drawing 10a.Part of an emitter with an oval-shaped filter cavity and contours. Drawing 10b.Cut of the oval-shaped cavity of the emitter of Drawing 10a. Drawing 10c.Detail of the operation of the oval shaped cavity of the emitter of Drawing 10a, with a comparison of the positions of the membrane. Drawing lOd.Detail of the variation of the filter with a large void space. Drawing lOd.View of the variation of Drawing lOd without the membrane. Drawing lOf.Operating positions of the membrane for different pressures of the variation lOd. Drawing lOg.Variation of the filter of an emitter with a membrane which is not flat. Drawing 1Oh.Variation of the filter of an emitter with a membrane from variable thickness bands. Drawing 101.Cut of the filter of Drawing lOh in operation. Drawing 10k Plan view of the membrane of the filter of Drawing lOh. Drawing lOlPlan view of the membrane of the filter with circular slots. Drawing 10m.Emitter with a meander - like flow restricting path at the base of the filter. Drawing lOn.Cut of the emitter of Drawing 10m. Drawing 11 Another view of the emitter of Drawing 8. Drawing 12 A cut of a self compensating emitter with successive two-hole cavities. Drawing 13 A view of the emitter of Drawing 12 without the membrane. Drawing 14 Another cut of the emitter of Drawing 12. Drawing 15 Another view of the emitter of Drawing 12 from the side which is attached to the tube. Drawing 15a.A view, according to the view of Drawing 15 of a variation of the emitter of Drawing 12 in the shape of a meander. Drawing 16 Detail and phase of operation of a two-hole cavity of the emitter of Drawing 12. Drawing 16a Detail and phase of operation of an elevated special rim of the emitter of Drawing 12. Drawing 16b.View of the rim of Drawing 16a without the membrane. Drawing 16cDetail and phase of operation of a cavity with unequal rim heights. Drawing 17 Detail of a four-hole cav ' ity. Drawing 17aCut X-X and phase of operation of the cavity of Drawing 17. Drawing 17bCut X-X and phase of operation of the auxiliary hole of Drawing 17. Drawing 18 Plan view of an emitter of known technology with two auxiliary holes, according to our invention. Drawing 19 Cut of an emitter with consecutive cavities a pairs of channels and rims. Drawing 19a Plan view of the emitter of Drawing 19 witho the membrane. Drawing 20 Cut of an emitter with consecutive cavities a pairs of channels and rims and two independent membranes. Drawing 20aPlan view of the emitter of Drawing 19 without the membranes. Drawing 21 Cut of a cylindrical emitter from elastomeric material and consecutive cavities with pairs o channels and rims. Drawing 21aPlan view of an emitter of the Drawing 21. Drawing 21bCut of the emitter of Drawing 21 in its phase of operation Drawing 21cVariation of the filter of the emitter of Drawing 21 Drawing 21dVariation of the filter of the emitter of Drawing 21 Drawing 22 Emitter with consecutive cavities with an arrangement for the reduction of its internal water pressure. Drawing 22aPlan view of the emitter of Drawing 22, withou cover. Drawing 23 Emitter with consecutive cavities and an additional arrangement for further pressure reduction at the rear part of the membrane. Drawing 23aPlan view of the membrane of the emitter of Drawing 23. Drawing 24 Emitter with an arrangement for the reduction of the internal pressure and a meander - like flow restricting path. Drawing 25 Emitter with an arrangement for the reduction of its internal pressure and two membranes. Drawing 25aPlan view of the cavity with the pair of the compensating rims of the emitter of Drawing 25. Drawing 25bVariation of the membrane of the emitter of Drawing 25. Drawing 25cCut of the emitter with the nozzle and a filter activated by the inlet membrane. Drawing 25d Cut of the emitter with the nozzle and a filter activated by the outlet membrane. Drawing 26 Emitter with an arrangement for the reduction of its internal pressure consisting of a large number of holes. Drawing 26aCut of the emitter of Drawing 26. Drawing 26bVariation of the emitter of Drawing 26, where the pressure in the rear part of the membrane is the same with the pressure in the tube. Drawing 26c Cut of a part of the emitter of Drawing 26b. Drawing 27 Variation of an emitter with an arrangement for the reduction of the internal pressure with the membrane near the axis of the tube. Drawing 27aPlan view of the emitter of Drawing 27 from the side of the tube. Drawing 28 Plan view of an emitter with a meander - like flow restricting path of a concave cylindrical surface and a membrane of a gradually increasing thickness. Drawing 28aCut of the emitter of Drawing 28. Drawing 28bCut of the emitter of Drawing 28. Drawing 29 Emitter with a meander - like path of a concave conical surface with converging vertical sides. Drawings 29a-d Cuts of the emitter of Drawing 29. Drawing 29e All the successive cuts of the membrane of the emitter of Drawing 29 are illustrated, for the same water pressure. Drawing 30 An emitter of a meander - like flow restricting path of a concave conical surfaces with parallel sides. Drawing 30aCut of the emitter of Drawing 30. Drawing 30bAll the cuts of the cone of the path of the emitter of Drawing 30. Drawing 30cAll the successive cuts of the membrane of the emitter of Drawing 30 are illustrated, for the same water pressure.

Claims: CLAIMS l.A conventional emitter with a path for the reduction of the pressure of the water with a water inlet and outlet; the path consists of repeated part of a basic prismatic form (1) which extend on both sides from the sides to the central longitudinal axis along the whole height of the emitter and which are at a distance d of each other. The path is surrounded by concave (la) and convex (lb) cylindrical side surfaces, at right angles to the base (2) which converge to an edge (3) vertical to the base, approximately in the area of the central longitudinal axis of the emitter (6) with a water path width d2 in the region of the edge (3), characterised by that cylindrical craters (4) are raised from the base (2), such crates terminating at the height b, approximately at the middle of the height of the emitter; the craters (4) are developed in the areas of the concave (la) surfaces of the basic prismatic forms (1) which form part of the craters, where such concave surface (la) forms a hydrocyclone with the crater (4) with an axis perpendicular to the base (2), wherefrom a number N of almost wedge - shaped prisms (5) with sharp edges of an edge width (5a): 0 - 0.15 d, are raised, such prisms terminating at the same height b, with the cylindrical craters (4), where such wedge - shaped forms (5) extend almost radially relative to the edge (3) of the form (1) in the regions which are defined within an angle of 70 degrees before and after the edge (3), with the edges (5a) being straight lines at right angles to the edge (3), and where one surface of such forms (5) is concave and almost cylindrical (5aa) with an axis parallel to the base (2), where such forms (4, 5) have a height b, whereas the basic forms (1) extend along the whole height b+Dl of the emitter, with the values of b almost in the regions 0.5d - 0.8d and 1<N<6, or N>1 for each elementary surface dXd2. 2.Emitter according to claim 1, where the crater (4a), of the hydrocyclone is in some part open, along the height of the crater (4a), or where a smaller crater (4c) with a smaller basic form (lc) is also added opposite to the basic one (4) and t basic form (1) . 3.Emitter according to claim 1, where the basic triangul form (57) is symmetrical, consists of flat (57b) and conca (57a) surfaces, where of the radial forms of the base have different formation each, such as symmetrical flat surfaces wi an isosceles (57c) or right - angled (5e) triangular cro section, or a concave and a flat surface (5) . 4.Emitter according to claim 1, where the basic prismat forms extending on either side are non - symmetrical (Dr. 6 and the hydrocyclones have different dimensions. 5.Emitter according to claim 1, where apart from the bas prismatic form which has the shape of a right - angled triangl smaller prismatic forms exist (lc) at the ends of the prismat forms of the base, such forms being extending radially (5b) having a different direction (5g), or parts of forms (5d, 5 with straight (5b) or curved (5c) edges, or raised pins 6.Emitter according to claim 1, consisting by a combination of the three different types of forms, i.e., t basic prismatic, the hydrocyclone, the radially extending for of the base, or any combination of only two of the above type of forms. 7.Emitter with a path for the water pressure dro according to claims 1-6, suitable for positioning onto the tube consisting of two co-axial cylindrical parts (13, 15) and cylindrical base (14), where the path of the water develop along the periphery of the external jacket of the inne cylindrical disk (13) and is covered externally by the cylinde (15) which bears the water outlet nozzle (11), whereas the wate supply from the tube is performed by the nozzle of th cylindrical base (14) . 8.Emitter according to claims 1-6, where the path for th water pressure drop is developed at the external surface of cylindrical body and where the internal surface of the tub forms the external jacket of the water path. 9.Emitter according to claims1-6, where b<0.5 d or b>0.8 d, and M≥6, with base forms extending to regions further than 70 degrees before and after the basic edge(3). 10.Emitter according to claims 1-6, where the edges of the forms of the bottom are not sharp and the width of the edge 5a is larger than 0.15 d. 11.Self compensating emitter consisting of a cavity (17), an elastic membrane (24) with thickness d and diameter D2, which covers the cavity (17), at the centre of which a hole exists, with a rim (19a) and a diameter Dl, where the water inlet to the cavity (17) under the membrane (24) which is at a distance a from the rim of the cavity creates a pressure reduction which forces them membrane (24) to move and be bent continuously, according to the pressure differences, so that the supply is kept constant, such emitter being characterised by that the cavity (17) bears a sharp edge (17a) and radially arranged shallow channels (18) extending to the whole surface (17b) of the cavity (17), by that the membrane (24) covers exactly the edge (17a) of the cavity and that its side surface (24a), due to the relatively movement, displaces foreign particles in a mechanical manner from the edge (17a) and by that the following relations holds: d < a , 3 Dl < D2 12.Emitter according to claim 11, where the membrane (24, Drawing 8d) has a larger dimension and covers the cavity (17) . 13.Emitter according to claims 11-12, where the cavity (17, Drawing 10a) is oval shaped, closed contours (26a, 26b, etc.) appear in its internal surface which are successive contact positions of the membrane with the cavity, and which are positioned at a level below the position (24c) which corresponds to the full immersion of the membrane into a flat- base cavity (27), so that a larger degree of lowering of the membrane in the periphery as well, and a gradual water pressure drop between the contours are achieved. 14.Emitter according to claims 11-13, where in place the peripheral edge (17a) arms (28) are located, such ar supporting the membrane (24), where the cavity is replaced the contour (26a) which is at a semantic distance f from t membrane. For better performance, the following relations must hold: f « dl, 3 <D2/D1 < 10 15.Emitter according to claims 11, 12, 14, where t cavity 17 is flat. 16.Emitter according to claim 13, where a flow restricti meander - like path (20) exists at the base of the cavity. 17.Emitter according to claims 11 - 16, where the membra bears radially arranged slots or is thinner in the periphery. 18.Emitter according to claims 11 - 17, where d > a a 2D1 < D2 19.Emitter according to claims 11 - 18, where the membra is not flat but assumes the different forms of the variations the cavities (17) of the claims 11-18 or a large number of sma shallow radially arranged channels in the shape of a saw or wi a different cross - section, relative to the small channe (18) which are developed along the length of the edge, wi which the membrane comes into contact with the emitter. 20.Emitter according to claims 11 - 19, where t membranes bear slots(41) and bands (42), (42a) of the same different thickness of various forms and kinds of supportations so that a relative movement between the bands is achieved in t region of the slots, without affecting the width of the slot (41). 21.An emitter according to claims 11 -20 where after t cavity (17) and the membrane 24, which covers the mebrane an forms a unified system which can operate as a filter an partially as a flow compensating device, or as a filter only where, such system is positioned before any other flo compensating arrangement, for achieving the water pressure drop a path (20) or where alternatively, other cavities or arrangements may exist for the final flow compensation. 22.Self compensating emitter featuring water inlet outlet, consisting of cavities (31, 33) with the dimensions L1,W1 and L2,W2 corresponding which feature one inlet hole (29, 30) and one outlet hole (29a, 30a) each, such cavities being covered by a membrane (24) which is located at a distance a from the base of the cavities, the emitter being characterised by that the cavities are arranged in a succession, the holes (29, 29a) (30, 30a) have the same diameter Dl, and are positioned symmetrically and very near each other, with almost common rims (29b, 30b) respectively, where the dimensions of the cavities (31, 33) LI , Wl and L2, W2 are progressively reduced as we advance towards the outlet or the depth a of the cavities is progressively increased as we advance towards the outlet or the thickness of the membrane gradually increases as we advance towards the outlet where the water is subject to exactly the same pressure drop due to friction in each of the two holes of the cavity, as the membrane (24) is in the same depth bent above the common rims (29b, 30b) and maintains a unified distance x from each rim. 23.An emitter according to claim 22, where each cavity has two or more inlet holes (29, 29d, Drawing 17), two or more outlet holes (29a, 29e, Drawing 17) with small channels (29f, 29g) with the height of the rims of the holes of each group being different from hole to hole. 24.A self compensating linear or cylindrical emitter with or without a flow restricting meander - like path and a cavity for pressure compesation of a single main hole or channel, where a second auxiliary hole or a channel of a different rim height exists. 25.An emitter according to claims 22-24 where in the place of the couples of the holes of the cavities (31, 33), couples of channels (29, 29a) appear, being formed between the two prismatic forms with inclined rims (36, 37). 26.An emitter according to claims 22 - 25 where t cavities (31, 33) are covered from both sides by membranes (24 24d). 27.An emitter according to claims 22-25 where the body such emitter and the cavities (31, 33, 34) are cylindrica where such cavities have the same thickness ΔW, so that t lengths LI, L2 are gradually decreased as we advance towards t outlet, or where the lengths LI, L2 are the same and t thickness ΔW is increased as we advance towards the outle where the water inlet to the emitter is performed along t perimeter via a cylindrical moving filter of a fluctuating vo space which is created by the internal surface of the tube a the blades (40) of the emitter, or such filter may occupyi only part of the periphery of the emitter. 28.Self compensating emitter with a water inlet hole of diameter Dl, at the end of which a flat surface (19c) has be formed with cavities and holes or channels and rims, for wate inlet and outlet into the cavities, with a flat membrane (24 which covers the flat surface (19c) and the cavities, suc emitter being characterised by that the flat surface (19c) wit the rim (19d) and a diameter D2 (with D2/D1 > 2) is positione before one or more cavities for the compensation of the wate flow, arranged in a succession (17, 31, 32, Drawing 22) or i positioned before meander - like flow restricting paths (31, Dr 24) where the water flow between the membrane and the fla surface and the rim (19d) causes a drop in the pressure o water, such drop being transferred to the following cavitie (17, 31, 33) as well as to the space (45, Drawing 22) behind th membrane. 29.Emitter according to claim 28, where the space behin the membrane (24) is divided into two isolated spaces (45, 45a and where the pressure prevailing in the second space (45a) i lower than the pressure prevailing in the first space (45). 30.Emitter according to the claims 22-29, where the water inlet is performed by a large number of holes (19) with a common rim and common flat surface(19c, Drawing 26). 31.Emitter according to claims 28-30 where the flat surface 19c and the flat surface of the membrane are replaced by convex and concave spherical surfaces, or where both surfaces are flat, but the rim (19d) is absent, or where D2/D1 < 2. 32.Emitter according to claims 28-31, where after the throttling surface (19c) at least one meander - like path or one cavity or an arrangement for compesation follows. 33.Emitter according to claims 28-32, where two independent membranes exist (24d, 24e, Drawing 25) the first of which covers at least the rim (19c) or the rim(19c) and meander - like paths and flow compensating cavities or arrangement, and where the other covers flow compensating cavities, or arrangement. 34.Emitter according to claims 22-33, where only one cavity with two holes or two channels, or one hole and one channel with the same or different rim height exists, with or without a meander - like path. 35.Emitter according to claims 22-33, where the distance X of the membrane from the rims or the bottoms of the cavities is each time not exactly the same for all the rims or the bottoms, where the pressure drop is not the same in the two holes - rims of each cavity, where the dimensions of the cavities L, W are not gradually reduced as we advance towards the outlet, and where the depth a of the cavities is not increased progressively as we advance towards the outlet, and the holes have different dimensions. 36.A filter system at the water inlet to the emitter with a nozzle and a hole at the end of which a surface has been formed (19c, Drawing 25c), with a membrane (24e) which covers the surface (19c, Drawing 25c)or the flow compensating cavity (33, Drawing 25d), characterised by that under the membrane (24e) a piston exists (54) with a flexible disk (55) at its end so that when the membrane is lifted and returns to position top of the surface (19c, Dr. 25c), or when it is bent over t cavity (33), a relative motion exists between the disk (55) a the nozzle which removes foreign particles. 37.A self compensating emitter with water inlet and outl with a meander - like path (31), prismatic forms (31a, Drawi 28) and a membrane (24) characterised by that the prismat forms (31a, Drawing 28) are engraved on to a concave cylindric surface (16b) with an axis parallel to the axis of the emitte and by that the thickness of the membrane (24, Drawing 28) increased progressively as we advance towards the outlet of t emitter, or the depth a of the base is progressively increas as we advance towards the outlet so that with the reduction the pressure created under the membrane, the distances of t membrane f from the bottom are the same along its whole length. 38.A self compensating emitter with a water inlet a outlet, with a meander - like path (31), prismatic forms (31 31b, 31c, Drawing 29), vertical sides(53) and a membrane (2 Drawing 29) of a constant thickness, characterised by that t prismatic forms (31a, 31b, 31c), are engraved onto a conic surface with a generating line almost touching the bottom of t path, two other generating lines passing from the points Al, B Cl, where the vertical sides (53) of the path (31) conver towards the outlet of the emitter, so that the distances of t membrane from the bottom during the operation are the same alo its whole length. 39.A self compensating emitter according to claim 3 where the vertical surfaces(53, Drawing 30) of the path (31) a parallel, their depth progresses gradually as we advance towar the outlet (30) and the two generating lines which are defin by the points A, B, C pass either outside or inside the pa (31, Drawing 30) . 40. Emitters according to claims 1-39, where or t emitters bodies are manufactured with elastomeric materials, o the membranes are not flat and or the shape of the emitters a the systems are suitably altered so that their positioning 0N- line or IN-Line is possible.

Inventors: DERMITZAKIS EMMANUIL, DERMITZAKIS, EMMANUIL
Applicants: DERMITZAKIS EMMANUIL, DERMITZAKIS, EMMANUIL
Application year: 1996
Main classification: A01G25
IPC codes: A01G25