CA1117165A - Drop feed irrigation - Google Patents

Abstract

ABSTRACT
The invention relates to a water feeding head suitable for water supply to row crops, particularly vineyards and orchards.
Its use enables the drop feed type irrigation of loose soils so far unsolved. The water feeding head is assembled from two parts, i.e. from a body releasably connected e.g. with a thread to the pipeline and from a replaceable nozzle fitted to the body. The nozzle is provided with one or several orifices discharging the water by drop feed method, and the heads are arranged along the pipeline at a distance from each other in accordance with the transmissivity of the soil.

Description

71~5 The invention rela-tes to a water feediny head for drop feed irrigation of row crops, e.g. vineyards and orchards. The water Eeeding head is connected with a water pipeline that is part of an estahlished or at least -temporary water distribution system supplied from some kind of water source, and is provided with an attachment to the pipeline and a water discharge orifice.
Drop feed irrigation systems started to gain general accept-ance all over the world at the end of the 1960's and beginning of the 1970's. It differs from the previously used irrigation methods in that the quantity of irrigation water necessary in each irriga-tion season is delivered at a continuous rate, or at least at short intervals, instead of on the four-five occasions, or at the 3-4 weekly intervals as was cutomary in Hungary.
Its most important domestic field of application is in the irrigation of vineyards and orchards. In this application, for example a polyethylene hose of small diameter is fastened to the lower metal rope of the wall-tree of a vineyard or orchard (in the absence of a wall-tree it is fastened for instance onto a row of poles, etc.), and the drop feed heads are screwed into this pipe usually at a spacing of 2-4 m. The diameter of each head is normally 0.2-0.6 mm and the water at low pressure in the hose is delivered by dripping onto the soil. The water permeates the soil, thus it wets the root system of the plants, or - in the case of faults in the system - only part of it.
The most importantadvanta~es to be derived from large-scale drop feed irrigation are the following: water content of the soil can be regulated very well~ the optimal water content le~el is almost continually ensured,. the irrigation itself does not require ';

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7~f~5 manual labour after laying o~ the pipes; the process of irrigation can be relatively easily automated. (By keeping the waker supply at optimal level, 200-300 q/ha additional yield of apples has been achieved in Hungary).
Some oE the disadvantages are: the small diameter drop feed heads are easily cloyged, a disadvantage in large-scale farming where several hundred thousands or millions of heads are operating~ that may make such large-scale application questionable;
the drop feed heads spaced at a distance of several meters in the line are not capable of wetting the entire growing area of the fruit trees, not even in case of impermeable ground and as a result the root systems of the trees become distorted (they develop vigorously in the irrigated parts, while they lag behind in dry areas);
insertion of the heads onto the pipe is not mechanized, which is a major disadvantage when irrigation is to be carried out on a large scale.
Spray heads are fre~uently used - mainly in Austria and the USA, where either a single water jet emerges from the spray nozzle and by hitting a plate in front of it, is sprayed, or fog-like fine spray emerges through 8-10 tiny - a few tenths of a mm diameter - holes. The spray heads are used for freshening the foliage of Citrus plants. With the fog-like spray the microclimate ; of the foliage is improved. These apparatuses are not suitable for the irrigation of a strip of land area and for delivery of irrigation water to the root system of the plants. Furthermore, no rain-type irrigation is realizable, which through the uniform permeation of the soil would provide an appropriate water supply ~ for the fruit trees indigenous to Europe. The reason for this is :~
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7~L65 that the irrigation water is not controllable, it does not permit in-termittent operation, and in adclition the layiny and relaying of -the system requires substantially manpower.
A particular type of apparatus functioning according ko the above principle is provided with a water feeding head ~uitable for the irrigation of circular areas. It has approximately 15 small diameter (about 0.7 mm) holes. The heads discharging the sprayed water are placed in the crowns of the trees. The diameter of the irrigated area is about 0.5 m. The disadvantages of the device are that owing to the spraying method the evaporation loss is high, and there is no possibility to increase the size of the irrigated area.
Another known solution for water feeding heads operating with an impacted water jet uses a hole of 0.3 to 0.6 mm for discharge of the water. The emerging jet hits a plate in front of it, gets sprayed, then falls by gravitation. According to experience, even this water feeding head is suitable only for the irrigation of the foliage, or crowns of the trees, but is unsuitable for the e~ficient water supply to the soil.
Water discharge nozzles also exist which imitate the so-called spray heads. They are reduced size versions of a pipe and nozzle of the sprinkler type spray head. The outlet diameter is about 0.3 to 0.4 mm. The nozzle-end opposite to the outlet orifice is provided with a thread which can be screwed for instance into the cross pipe inserted in the irrigation system. With the aid of the nozzles the spray is trained on the stalks or stems of the row crops, e.g. vines. The results are not favcurable. As a result of sunshine the pipeline suffers deformation, consequently '`:1 ~' ~, ' : . .

~71~i the position of khe nozzle will be altered. In addition, owing to the very large number of nozzles the assembly and operation are labour-intensive.
The so-called feeder spirals are found amon~ the relatively more advanced water feeders, one end of which is pushed into the hole in the wall of the cross pipe of the pipe system, then the spiral is wound onto the pipe. The spiral is provided with internal hole of 0.4 to 0.6 mm diameter. A drawback of the system is that the diameter of the hole cannot be increased unless the length of the spiral (being 1.0 to 1.5 m at the present) is increased considerably. Because of the small diameter of the hole it is necessary to purify the irrigation water to the quali-ty of drinking water, which is rather expensive. It is also unfavourable that no fertilizer can be delivered to the soil with the water feeding spiral.
Amongst the most advanced varieties of the water feeding heads are those which deliver the moisture to the soil by way of dripping. A characteris*ic type of these is described in the French Patent Specification No. 2,185,349. Discharge of the water is carried out by large-headed nails pressed into the so-called cross pipe provided with gaps and/or holes of various shapes and sizes.
The large-headed nails may be provided with some kind of cap that prevents passage of the water directly in a jet form. This system has failed in practice, because the geometrically complicated design of the heads makes them sensitive to clogging.
Similarly drop feed type irrigation apparatus can be found in the French Patent Specification No. 2,268,460. So-called water feeding bodies are inserted into the cross pipe of the water supply '~

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system and Eixed with clamps to -the pi.pe. The body may be provided with various replaceable heads, which discharge the water through ; the orifices developed along the mantle surface. Design of the heads is complicated. The heads are sensitive to clogging. They are material-intensive and their p:roduction is difficult, hence unsuitable for large-scale purposes.
The drop feed type spray h~3ad described in the French Patent Specification No. 2,201,719 is formed as a drop feed body and can be inserted not only in radial but also in axial direction into the pipe so that the water is conductible right through the head. The water is delivered in small drops to the soil. The construction of this head is complicated, its production is expensive and the very narrow gaps are inclined to clog quickly.
The drop feed type feeding head described in the French Patent Specification No. 2,229,347 is also mountable in the pipeline as a pipe connecting adapter. One end of the pipe connect-ing adapter is provided with a flat thread and it discharges a water quantity according to the geometrical parameters - shape, depth, number - of this thread. The disadvantages are the same as in those heads mentioned earlier.
; Finally it is worth mentioning the drop feed body which can be inserted into low pressure water supply systems and is used for ploughland irrigation. This is described in the French Patent Specification No. 2,173,616. The drop feed body i~ provided with a thread and the water quantity is regulated by screwing a threaded pin in and out. sy screwing the threaded pin fully in, the water feed is cut off. The emerging water flows in the ~ grooves of the threaded part and passes to the outlet orifice.

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J ~7~5 The system is ingenious, but extremely complicated, and the irrigation conditions are not more favourable than with the branching pipes provided with clamps. It is too expensive for the small-scale farm, on the other hand in the large-scale farms -owing to the constantly necessary adjustment of the threads and high demand for the labour force - its use is impractical.
The pipelines to be found in the French Patent Specification No. 2,213,731 are accessories of irrigation plants. From the description and drawings it appears that the liquid is forced to pass along a spiral thread and its flow conditions and the rate of flow are determined by the pitch. The water feeding orifices are arranged in the external mantle surface of the pipe, through which more or less drop feed-type water discharge is to be achieved.
This water feed is not realized. The water passes from the internal so-called water delivery pipe into the external irrigation pipe, but it travels only a short distance in the space be~ween the two pipe mantles and even that under unfavourable and practically uncontrollable flow conditions.
The French Patent Specification No. 2,216,90~ demonstrates an irrigation device permitting quantitative control. The vital part of the device is the adjustable threaded drop feed head placeable into the pipe. The water flows in the grooves of the sleeved drop feed thread. A thread regulating the quantity of the outflowing water may be developed in the interior of the pipe. The drop feed head can be fixed in the pipe in a horizontal arrangement too. This system is also extremely complicated, hence its production is costly and maintenance difficult. For this reason it gained no general use in the practice.

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The invention is aimed at the development of a water feeding head ~Jith the aid of which row crops, for example orchards can be supplied with water, and not only on the customary seasonal 4-5 occasions (i.e. at intervals of several weeks), but at a continuous rate during the growth season.
The present invention is based on the recognition that drop feed irrigation should be realized with holes of large diameter instead of the spray heads c~f 0.2 to 0.6 mm hole diameter used so far, whereby a multiple of the earlier water quantity can be delivered to the ground. It is pertinent to the recognition that one or several water streams should emerge at low pressure from the water feeding head of small size but with relatively large hole diameter, and each of these water streams should reach the ground at a particular spot. Density of the irrigated spots is determined with the types and spacing of the heads in such a way, that an irrigated strip of approximately uniform width should develop on the ground surrounding the row crop from both sides.
According to the present invention there is provided a drop-feed irrigation system for row crop watering comprising:
at least one pipeline spaced above the ground to be watered and for delivering water at a pressure of no more than 0.75 m water column and provided with a plurality of tubular bodies spaced along said pipeline and extending downwardly therefrom, each of said tubular bodies having a tapering configuration; and respective one-piece nozzles interchangeably mounted on said tubular bodies, each of said nozzles being formed with a cylindrical portion having a bore open at one end for receiving said respective tubular body and communicating therethrough with said pipeline, said nozzle , being further formed with a plurality of orifices, each having a diameter grea-ter than 0.6 mm and formed at the other end of said nozzle and communicating with said bore, at least two of said orifices being directed laterally ancl substantially radially with respect to the axis of said nozzle, said orifices being axially spaced from the lower end of the respective -tubular body, said orifices of said nozzle being so oriented and said tubular bodies being so positioned along said pipeline that water carried therein is discharged therefrom in a trickling stream onto said ground at a continuous network of watering points along said pipeline.
Preferably, each .nozzle is formed with a frustoconical portion at its other end, and the orifices form angles other than 90 with the axis of the nozzle.
The main advantage of the irrigation system according to the invention is that it meets the requirements for drop feed irrigation of loose soils. This drop feed irrigation is achieved with the aid of a pipeline and a large number of wate~ feeding heads connected to the pipeline. Its technical advantage is that each head is formed by a tubular body and a nozzle which are separable. The body is identical in every case, and consequently its production and insertion into the pipeline can be accomplished with high productivity and efficient mechanization. The bodies of identical construction allow the connection of various nozzles with maximum adaptation to the need and with precision replacement.
Experience with irrigation systems according to the invention has been definitely favourable so far. In the case of individual plants, e.g. fruit trees, irrigation at one or two points is replaced with the supply of water to the whole strip ~l17~i65 where the root system of the plants is si-tuated.
It i5 also favourable tha-t the wa-ter can be directed to the require~ spot with the water eeding head, and -the size of the nozzles and spacing of the heads along the pipelines make it possible that the so-called total permeation in the required strip of the ground should take place with a margin of safet~, and thus the optimal water content will be available for the soil with respect to the plant in question. This is facilitated also by the irrigation being suitably intermittent and programmable.
The system according to the invention provides a solution to the internationally recognized problem of efficient irrigation of orchards in loose, sandy soil with small water portions at low pressure. The system retains all the known advantages of drop feed irrigation and at the same time it eliminates all the disadvantages so far inhibiting large-scale application. In reality only the elements and principles of the drop feed irrigation have been retained, thus the nozzles mounted on the pipeline, the low operating pressure and the lateral seepage in the soil. Con-sequently the subject of this invention can be no longer regarded as a drop feed head, but rather as a water feeding head.
In the accompanying drawings, which illustrate exemplary emobdiments of the present invention:
Figure 1 illustrates the connection of pipeline and water feeding head;
Figures 2 to 5, are longitudinal sections of various embodiments of the nozzles, Figures 6 to 13, are cross sections of various embodiments of the nozzlesL ancl 9_ ..

Figures 14 to 18 are schema-tic plan views showing the irrigated strip of the ground with nozzles provided with various orifices.
Figure 1 shows the pipeline 1 with one water feeding head assembled from the tubular body 2 and the nozzle 3. The tubular body 2 is radially inser-ted into the pipeline 1, preferably secured with a screw nut, with the longitudinal axis 7 of the nozzle 3 perpendicular to the longitudinal axis 9 of the pipeline 1.
Figure 2 shows an embodiment of nozzle 3 which is provided with a single axial orifice 4 on the longitudinal axis 7. The mantle surface 8 of the nozzle 3 is a straight cylinder as .in the embodiment illustrated in Figure 3. The interior 6 of the nozzle 3 is similarly cylindrical in both cases. In the embodiment according to Figure 3 the irrigation water passes from the interior 6 through the radial orifices 5. Their axes are at an angle of ~0 to the longitudinal axis 7 of the nozzle 3.
In Figures 4 and 5, the mantle surface 8 of the nozzle is shaped with a frustoconical portion at the lower end of the cylindrical part. In Figure 4 the frustoconical portion is of downwardly increasing diameter in relation to the mantle surface 8, while its diameter is decreasing in the embodiment shown in Figure 5. In both cases the nozzle 3 is provided with the radial orifices 5 arranged on the frustoconical portion of the nozzle 3.
Figure 4 shows that axes o~ the radial orifices 5 are at an obtuse angle to the longitudinal axis 7 of the nozzle 3, while they are at an acute angle in Figure 5. Figures 2 to 5 show that ~he interior 6 of the nozzle 3 ends in a concave conical surface at its end opposite the connection to the body 2.

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Figures 6 to 13 ill~ls-trate cross sections of various embodlments of the nozzle in a plane perpendicular to the longitudinal axis 7 of the nozzle. Figures 6 and 7 show two radial orifices 5 and these are combined with an axial orifice 4 in Figure 7. Figure 8 shows four raclial orifices 5 at 90C ko each other, while in the nozzle cross section shown in Figure 9, four radial orifices are spaced around the outer surface 8 of the nozzle 3 in such a way that the adjacent radial orifices 5 are at alternating acute and obtuse angles to each other.
Figure 10, like Figure 8, illustrates four radial orifices 5 at a central angle of 90 to each other, but the nozzle 3 is provided with the axial orifice 4 as well. The nozzle cross section in Figure 11 can be regarded as a version oE that shown in Figure 9, where the radial orifices 5 are similarly associated with an axial orifice 4.
In Figure 12 the nozzle 3 has five radial orifices 5, while in Figure 13 besides the same spacing of the radial orifices 5, one axial orifice 4 is also available.
Figures 6 to 13 demonstrate that the water emerges in two, three, four, five or six streams from each water feeding head in accordance with the number of orifices. According to agrotechnical experience, those embodiments of the nozzle 3 seem to be preferable where no vertical water stream is discharged from the water feeding head. If the applied pressure does not exceed 0.75 m water column pressure, then the water passes out of the water feeding head not in the form of a jet, but by drop feed, providing a trickling stream. At such low pressures, the moisture reaching the soil in a vertical direction has a favourable effect.

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The exper:iments conduc-ted with drop feed and with discharge of water s-treams :in various direc-tions and intensities demonstrate that drop feeding to a particular spot is not favourable, because the mineral substances washecl out of the soil at khe edge of the wetted strip of ground ma~ produce permanent salt deposits. On the other hand, at the water stream discharging heads the width of the irrigated strip 11 can be varied within wide limits by variation of the pressure and the sa:Lt deposits can be reduced, and the still occurring minor salt deposits can be easily washed away through the so-called accumulated irriyation accomplished at the end of the growth season.
Figures 14 to 18 show the irrigation strip 11 and the network points 10 constituting a continuous system, which shows where the water s-treams from the water feeding heads reach the ground. Figure 14 shows the pattern when the water feeding head is equipped with the double orifice nozzle 3 illustrated in Figure 6. The irrigated strip ll shown in Figure 15 is pertinent to the nozzle cross section shown in Figure 7. In this latter pattern it is apparent that now and then a network point 10 falls in the traceline of pipeline l.
Figure 16 illustrates the case when the four network points 10 are situated along the corner points of an imaginary square.
This irrigation pattern is pertinent to the nozzle cross section shown in Figure 8. There is no separate diagram, but naturally it is easily conceivable that the imaginary square of Figure 13 is distorted to a rectangular shape if the nozzle 3 is of the cross section shown in Figure 9. Similarly, the irrigation pattern is complemented when the network point 10 falls in the traceline of S

the main pipeline 1 when the nozzle 3 is constructed as shown in Figures 10 or 11.
Figure 17 illustrates the irrigated strip 11 that is pertinent to the nozzle cross section shown in Figure 12. In the interest of lucidi-ty, the network polnts 10 brought about by two consecutive water feeding heads were marked in the illustration which shows that the water feeding heads are spaced along the pipeline 1 in such a way that the irrigated strip is reached by the water jets in a "set pattern".
Figure 18 similarly shows the irrigation pattern pertinent to the nozzle cross section according to Figure 13. The water streams reach the ground in both of the latter cases in network points 10, and seepage of the moisture starts ou-t from these points. The water delivery pipeline 1 passes preferably in the approximate line of the row crops, e.g. fruit trees, and thus the strip crossed by the root system can be supplied with moisture at an approximately uniform rate.
The water feeding heads of the present system are suitable for the realization of controlled irrigation, especially in the case of loose soils and mainly for row crops, at a lower cost and more effectively than with the systems existing until now.

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Claims (3)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A drop-feed irrigation system for row crop watering comprising:
at least one pipeline space above the ground to be watered and for delivering water at a pressure of no more than 0.75 m water column and provided with a plurality of tubular bodies spaced along said pipeline and extending downwardly therefrom, each of said tubular bodies having a tapering configuration;
and respective one-piece nozzles interchangeably mounted on said tubular bodies, each of said nozzles being formed with a cylindrical portion having a bore open at one end for receiving said respective tubular body and communicating therethrough with said pipeline, said nozzle being further formed with a plurality of orifices, each having a diameter greater than 0.6 m and formed at the other end of said nozzle and communicating with said bore, at least two of said orifices being directed laterally and substantially radially with respect to the axis of said nozzle, said orifices being axially spaced from the lower end of the respective tubular body, said orifices of said nozzle being so oriented and said tubular bodies being so positioned along said pipe-line that water carried therein is discharged therefrom in a trickling stream onto said ground at a continuous network of watering points along said pipe-line.

2. The system defined in claim 1 wherein said nozzle is further formed with a frustoconical portion at said other end thereof, said laterally directed orifices forming an angle other than 90° with the axis of said nozzle.

3. The system defined in claim 1 wherein at least one or said orifices is formed in said other end of said nozzle in alignment with the axis thereof.