RELATED APPLICATION

This application claims the benefit of priority of U.S. Provisional Patent Application No. 63/335,742 filed on April 28, 2022, the contents of which are incorporated herein by reference in their entirety.

FIELD AND BACKGROUND OF THE INVENTION

The present invention, in some embodiments thereof, relates to fluid dynamics irrigation and, more particularly, but not exclusively, to a system and method for measuring flow rate, e.g., within an irrigation distribution pipe.

Drip irrigation is a watering method that utilizes pressurized water sources and drips water along a distribution pipe in a controlled manner. Drip irrigation systems are considered to be more efficient than surface irrigation systems that typically distribute water in the fields by runoff. Surface irrigation systems require smaller investment and lower energy costs, and these systems typically employ high discharge at the inlet in order to irrigate efficiently and uniformly across a field so that water will reach the end of the field.

In drip irrigation system, drippers are inserted into or mounted onto a water supply line typically at regular intervals. Examples of drippers for drip irrigation system are described in International publication Nos. W02017/191640 and WO2019/092717, the contents of which are hereby incorporated by reference. These publications describe a dripper with a pathway that is not one-dimensional and that allows bypass routes around obstacles that may be inside the dripper.

U.S. Patent No. 4,209,131 teaches use of a flow meter to set limits to the quantity of water to be discharged by the irrigation system U.S. Published Application No. 20030183018 discloses use of a propeller, ultra sonic, or impeller flow meter, equipped with a microprocessor that calculates the quantity of water discharged by the irrigation system U.S. Patent No. 6,032,540 discloses an in-line flow meter drag paddle which is disposed to rotate in a fluid conduit for use in drip irrigation system U.S. Patent No. 4,454,758 discloses a shunt fluid flow measuring device for inserting into an irrigation pipe, including a Venturi tube, and a fluid bypass connected in series with a flow meter. U.S. Patent No. 5,423,226 discloses a portable flow measurement system which comprises a flow metering element and two differential pressure sensors for metering irrigation water use. SUMMARY OF THE INVENTION

According to some embodiments of the invention the present invention there is provided a method of measuring flow rate in an open pipe section. The method comprises: measuring a pressure difference within a pipe section across a segment of the pipe section, wherein a diameter of the pipe section is smaller at one end of the segment than at another end of the segment; accessing a computer readable medium storing a database having a plurality of entries, each comprises a pair of database diameters, and a database parameter describing a relation between pressure differences and flow rates at a pressure of less than 0.1 bars; and searching the stored database for a pair of database diameters that best matches the diameters of the pipe section at the ends, calculating the flow rate in the pipe section based on a value of a database parameter of a respective entry of the database, and generating output pertaining to the calculated flow rate.

According to some embodiments of the invention the segment is substantially horizontal.

According to some embodiments of the invention the method comprises correcting the database flow rate for a contribution of hydrostatic pressure difference due to a tilt of the segment relative to a horizontal plane.

According to some embodiments of the invention the measuring is by a differential pressure sensor.

According to some embodiments of the invention the measuring is by two pressure sensors each in fluid communication with one end of the segment.

According to some embodiments of the invention the accessing and the searching is at a remote location relative to the measuring and the method comprises transmitting information pertaining to the pressure difference and the diameters to the remote location, and receiving the output from the remote location.

According to an aspect of some embodiments of the present invention there is provided a system for measuring flow rate in a flow channel. The system comprises: an open pipe section to be introduced into the flow channel, the pipe section having a segment therealong, wherein a diameter of the pipe section is smaller at one end of the segment than at another end of the segment; a pressure measuring system constituted to generate a signal indicative of a pressure difference across the segment; and a signal processor configured to access a computer readable medium storing a database having a plurality of entries, each comprises a pair of database diameters and a database parameter describing a relation between pressure differences and flow rates at a pressure of less than 0.1 bars, to search the stored database for a pair of database diameters that best matches the diameters of the pipe section at the ends, to calculate the flow rate in the pipe section based on a value of a database parameter of a respective entry of the database, and to generate output pertaining to the calculated flow rate.

According to some embodiments of the invention the system comprises a level indication device mounted to provide indication when the pipe is substantially horizontal.

According to some embodiments of the invention the signal processor is configured for receiving a signal indicative of a tilt of the open pipe section, and to correct the database flow rate for a contribution of hydrostatic pressure difference between measurement points at the ends of the segment.

According to some embodiments of the invention the pressure measuring system is in fluid communication with the ends of the segment via two openings at a wall of the pipe section, and is connected to the openings by conduits that are filled with liquid during delivery of the system

According to some embodiments of the invention the openings are formed at a same azimuthal angle of from about 100° to about 170° with respect to a vertical direction, the azimuthal angle being defined downwards from an upper half of the pipe section.

According to some embodiments of the invention the measuring is by a differential pressure sensor.

According to some embodiments of the invention the measuring is by two pressure sensors each in fluid communication with a measurement point at a different end of the segment.

According to some embodiments of the invention the signal processor is at a remote location relative to the pipe section, wherein the system comprises a communication system configured for transmitting information pertaining to the pressure difference and the diameters to the signal processor.

According to some embodiments of the invention the diameters are selected such that the pressure difference is from about 1 mbar to about 10 mbar, at flow rate of from about 5 m ³ /h to about 30 m ³ /h.

According to some embodiments of the invention the diameters are selected such that the pressure difference is from about 1 mbar to about 6 mbar, at flow rate of from about 40 m ³ /h to about 80 m ³ /h.

According to some embodiments of the invention the diameters are selected such that the pressure difference is from about 1 mbar to about 7 mbar, at flow rate of from about 70 m ³ /h to about 180 m ³ /h.

Unless otherwise defined, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the invention, exemplary methods and/or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

Implementation of the method and/or system of embodiments of the invention can involve performing or completing selected tasks manually, automatically, or a combination thereof. Moreover, according to actual instrumentation and equipment of embodiments of the method and/or system of the invention, several selected tasks could be implemented by hardware, by software or by firmware or by a combination thereof using an operating system

For example, hardware for performing selected tasks according to embodiments of the invention could be implemented as a chip or a circuit. As software, selected tasks according to embodiments of the invention could be implemented as a plurality of software instructions being executed by a computer using any suitable operating system In an exemplary embodiment of the invention, one or more tasks according to exemplary embodiments of method and/or system as described herein are performed by a data processor, such as a computing platform for executing a plurality of instructions. Optionally, the data processor includes a volatile memory for storing instructions and/or data and/or a non-volatile storage, for example, a magnetic hard-disk and/or removable media, for storing instructions and/or data. Optionally, a network connection is provided as well. A display and/or a user input device such as a keyboard or mouse are optionally provided as well.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the invention may be practiced.

In the drawings:

FIG. l is a flowchart diagram of a method suitable for measuring flow rate in a flow channel according to some embodiments of the present invention;

FIGs. 2 A and 2B are schematic illustrations of a system suitable for measuring flow rate in a flow channel according to some embodiments of the present invention;

FIGs. 3 A and 3B are schematic illustrations of a drip irrigation system according to some embodiments of the present invention; FIG. 4 is a schematic illustration of a database which can be used according to some embodiments of the present invention; and

FIG. 5 is a schematic illustration exemplifying connections between a flow rate measuring system and a water distribution line of a drip irrigation system, according to some embodiments of the present invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

The present invention, in some embodiments thereof, relates to fluid dynamics irrigation and, more particularly, but not exclusively, to a system and method for measuring flow rate, e.g., within an irrigation distribution pipe.

Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth in the following description and/or illustrated in the drawings and/or the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways.

Even though flow meters are widely practiced, the inventors found that conventional flow meters are not without certain operative limitations, particularly in the field of drip irrigation, that would best be avoided. For example, conventional flow meters are designed to operate at relatively high pressures, e.g., of the order of 0.5 bars or more, but fail to provide adequate results at relatively low pressures.

Referring now to the drawings, FIG. 1 is a flowchart diagram of a method suitable for measuring flow rate in a flow channel according to various exemplary embodiments of the present invention. A representative example of a system 20 suitable for executing the method is illustrated in FIGs. 2A (isometric view), and 2B (cross-sectional view along the line A-— A' of FIG. 2A).

The method can be used for measuring flow rate of any liquid, including, without limitation, water, oil, and the like. The method is particularly useful for measuring the flow rate of water in an irrigation system, more particularly in a drip irrigation system, such as, but not limited to, a drip irrigation system that operates at low pressures (e.g., less than 100 mbar, or less than 90 mbar, or less than 80 mbar, or less than 70 mbar, or less than 60 mbar, or less than 50 mbar). For example, the method of the present embodiments can be used for measuring the flow rate of a drip irrigation system having drippers that are distributed along an inclined irrigation pipe, e.g., one of the drip irrigation systems disclosed in International Publication Nos. W02017191640 and WO20 19/092717, the contents of which are hereby incorporated by reference. In some embodiments of the present invention the flow channel in a water distribution line of the drip irrigation system The water distribution line supplies water to a plurality of irrigation pipes that are connected at a plurality of connection points along the water distribution line. Each irrigation pipe receives a flow of water from the distribution line and discharges the water through a plurality of drippers distributed along its length. A representative example of such a system, showing the water distribution line 52, at which the flow rate is measured according to some embodiments of the present invention, the irrigation pipes 54, and the drippers 56, is illustrated in FIGs. 3A-B.

The method begins at 10 and continues to 11 at which a pressure difference is measured within an open pipe section 22 across a segment 24 of the pipe section 22. Pipe section 22 is preferably positioned in the flow channel (e.g., distribution line 52, FIGs. 3A-B) and receives the liquid therefrom The direction of liquid flow in pipe section 22 is shown at 36. Preferably, open pipe section 22 is constructed such that the diameter of pipe section 22 is smaller at one end 24a of segment 24 than at the other end 24b of segment 24.

Typically, end 24a is downstream relative to end 24b, with respect to flow direction 36. In these embodiments, pipe section 22 can have a convergent portion 38 between ends 24b and 24a, as illustrated in FIG. 2A. It is appreciated that the flow channel (e.g., distribution line 52) is typically of a generally uniform diameter therealong. To allow system 20 to be positioned in such a flow channel, pipe section 22 optionally and preferably also has a divergent portion 48, optionally followed by a non-tapered downstream portion 49, for matching between the reduced diameter of pipe section 22 at end 24a of segment 24 and the diameter of the flow channel.

Alternatively end 24a can be upstream relative to end 24b with respect to flow direction 36. In these embodiments, pipe section 22 can have a divergent portion between ends 24a and 24b. These embodiments are not explicitly illustrated but an example of these embodiments may be understood by considering a reversal of the direction of arrow 36, in which case portion 38 serves as the divergent portion.

The pressure difference is optionally and preferably measured between two openings 26a, 26b at a wall of pipe section 22, where opening 26a defines a measurement point at end 24a of segment 24 and opening 26b defines a measurement point at end 24b of segment 24. The measuring 11 is by a pressure measuring system 34 that is in fluid communication with openings 26a and 26b by means of respective two conduits 32a and 32b, sealingly connected to openings 26a and 26b. Pressure measuring system 34 is optionally and preferably mounted on the external wall of pipe section 22 as illustrated in FIG. 2A. In some embodiments of the present invention both openings 26a, 26a are formed at the same azimuthal angle 0 with respect to a vertical axis 28 perpendicular to a longitudinal axis 30 of pipe section 22. When system 20 is deployed, pipe section 22 is preferably oriented such that axis 28 is co-aligned with the gravitational direction, such that openings 26a, 26a are at the lower half of pipe section 22. A typical value for 0 is from about 100° to about 170°, e.g., about 135° measured downwards from the upper half of pipe section 22. The advantage of having openings 26a, 26a at the lower half of pipe section 22, is that it reduces the likelihood for air bubbles to enter the conduits 32a, 32b and interfere with the measurement of the pressure.

Conduits 32a, 32b are preferably arranged outside pipe section 22. The distal ends of conduits 32a, 32b are sealingly connected to openings 26a, 26b, and the proximal ends of conduits 32a, 32b are sealingly connected to system 34 by one or more connectors 40.

The measurement 11 is preferably executed while conduits 32a, 32b are filled with liquid in their entirety. Optionally and preferably the conduits 32a, 32b are filled with liquid at all times throughout the time at which they are deployed with the flow channel at which the flow rate is to be measured. For example, while deploying system 20 in the flow channel, connectors 40 can be temporarily disconnected, so as to open the proximal ends of the conduits 32a and 32b to the atmosphere. This allows the liquid in the flow channel that enters the pipe section 22 to also fill the conduits 32a and 32b. While conduits 32a and 32b are filled, connectors 40 are sealed, thereby ensuring that conduits 32a and 32b remain filled as long as liquid flows in the flow channel.

Alternatively, conduits 32a and 32b can be filled with liquid during the delivery of system 20 to the deployment site. In these embodiments, the proximal ends of conduits 32a and 32b are sealingly connected to system 34 by connector(s) 40, and the distal ends of conduits 32a and 32b are sealed by seals or valves 42a, 42b. Prior to the first use of system 20, and following its deployment in the flow channel, seals or valves 42a, 42b are pulled, opened, punctured, or subjected to any other mechanical operation that establishes fluid communications between pipe section 22 and the conduits 32a and 32b.

Pressure measuring system 34 can include any analog or digital pressure sensor known in the art for calculating pressure or pressure difference. Representative examples include, without limitation, a compressed gas pressure sensor, a piezoresistive strain gauge sensor, a semiconductor pressure sensor, a capacitive pressure sensor, an electromagnetic pressure sensor, a piezoelectric pressure sensor, and a potentiometric sensor.

It is expected that during the life of a patent maturing from this application many relevant pressure sensors will be developed and the scope of the term pressure sensor is intended to include all such new technologies a priori. Pressure measuring system 34 can include a differential pressure sensor, in which case each of conduits 32a and 32b is connected to a different inlet of the sensor. In these embodiments, the measuring 11 comprises receiving a signal from the sensor, wherein the signal is indicative of the difference between the pressure in conduit 32a and the pressure in conduit 32b. Alternatively, pressure measuring system 34 can include two separate pressure sensors, in which case each of conduits 32a and 32b is connected to a different sensor. In these embodiments, the measuring 11 comprises receiving a separate signal from each of the two sensors and generating a signal which is the subtraction between the two separate signals, providing a subtraction signal that is indicative of the difference between the pressure in conduit 32a and the pressure in conduit 32b.

Referring again to FIG. 1, the method continues to 12 at which a computer readable medium storing a database. A representative example of a database 70 suitable for the present embodiments is illustrated in FIG. 4. Database 70 has a plurality of entries 72-1, 72-2, ..., 72-N, each comprising a pair of database diameters and a database value of a parameter. The parameter describes a relation between pressure differences across segment 24 and flow rates, and the database values of this parameter correspond to the database diameters. The database 70 is preferably prepared for parameter values calculated for a pressure within pipe section 22 of less than 0.1 bar. In the illustration shown in FIG. 4, database 70 is in the form of a lookup table.

It was found by the Inventors that for pressure of less than 0.1 bar, the volumetric flow rate Q correlates with the square root of the pressure difference Ap across the segment 24 according to the following formula: where A is the cross-sectional area the end 24a of the segment 24, g is the gravitational constant (approximately 9.8 m/s ² ), and k is a parameter that depends on the diameters of the pipe section 22 at the ends 24a, 24b of the segment 24. In this case, the database values of the entries of database 70 can be the values of the parameter k, or the values of 1-k, or the values of g/(l-k), or the values of 2g/(l-k), etc.

The method proceeds to 13 at which the stored database is searched for a pair of database diameters that best matches the diameters of the pipe section at ends 24a and 24b. The method then optionally and preferably proceeds to 14 at which the flow rate at pipe section 22 is calculated based on the database value of the respective database entry. The calculation is optionally and preferably according to EQ. 1 above. For example, when the database values are values of the k parameter, the calculation 14 is performed by substituting the respective database value for k in EQ. 1, when the database values are values of 2g/(l-k), the calculation 14 is performed by substituting the respective database value for 2g/(l-k) in EQ. 1, etc.

Following are representative examples for values of k suitable for the present embodiments, for several ranges of the diameter and /241, of segment 24 of pipe section 22. For 4/241, of from about 90 mm to about 110 mm and d^Aa of from about 70 mm to about 80 mm, the value of k can be from about 0.25 to about 0.32, for 4/241, of from about 90 mm to about 110 mm, and d^Aa of from about 55 mm to about 69 mm, the value of k can be from about 0.12 to about 0.16, for 4/241, of from about 140 mm to about 160 mm, and diAa of from about 90 mm to about 109 mm, the value of k can be from about 0.19 to about 0.24, for 4/241, of from about 140 mm to about 160 mm, and diAa of from about 110 mm to about 120 mm, the value of k can be from about 0.29 to about 0.36, and 4/241, of from about 161 mm to about 200 mm, and diAa of from about 140 mm to about 160 mm, the value of k can be from about 0.4 to about 0.5.

The database 70 is optionally and preferably prepared under the assumption that there is a predetermined difference in the heights of measurement points 26a and 26b relative to a horizontal plane perpendicular to the gravitational direction. Typically, the predetermined difference in the heights of measurement points 26a and 26b equals or approximately equals half the difference between the diameters 4/241, and diAa of pipe section 22 at ends 24b and 26b of segment 24. The calculation 14 is therefore suitable for cases in which the two measurement points 26a and 26b are at the predetermined difference in the heights that was used for preparing database 70. The database 70 is optionally and preferably also prepared under the assumption that the flow in pipe section 22 is generally horizontal. Thus, in various exemplary embodiments of the invention the pipe section 22 is leveled within the flow channel while deploying system 20 at the deployment site. For example, pipe section 22 can be provided with a level indication device 46, mounted on its external wall or on pressure measuring system 34, to provide indication when pipe section 22 is substantially horizontal.

In cases in which the two measurement points 26a and 26b are at different heights relative to the aforementioned horizontal plane, the method preferably continues to 15 at which the flow rate calculated at 14 is corrected for the hydrostatic contribution due to a tilt of segment 24. In these embodiments, the method receives data pertaining to the tilt, and performs the correction based on this tilt. The correction can be by means of the Bernoulli's principle, as known in the art.

The calculation of the flow rate using the database 70, and also the correction for the hydrostatic contribution (when applied) can be executed by a signal processor having a circuit 44 configured for receiving the signal or signals from system 34 and calculating the flow rate using the database 70. Alternatively, circuit 44 can be configured to transmit the signal to a remote location at which the flow rate can be calculated. For example, circuit 44 can be configured to transmit the signal, or more preferably a digital version thereof, via cellular or satellite communication network, to a cloud computing facility or remote computer, and the cloud computing facility or remote computer can access a computer readable medium storing the database 70 and calculate the flow rate.

In some embodiments of the present invention circuit 44 is also configured to function as a data logger that stores a data log containing previously calculated flow rates. Optionally, the data log is time stamped so that each previously calculated flow rate is associated with a time stamp indicating the date and time at which the measurement was obtained. The data log can be transmitted by circuit 44 to a remote location over a communication network. For example, data log can be transmitted by circuit 44 to a cloud storage facility.

Circuit 44 can also be configured to communicate, for example, by Bluetooth® communication protocol or the like, with a nearby device, such as, but not limited to, a smartphone, or a smartwatch, or a tablet. These embodiments are particularly useful when system 20 is deployed at off grid locations or locations at which cellular and wifi signals are weak, but embodiments in which circuit 44 communicates both with the nearby device, and with a computer or cloud facility at a farther location are also contemplated. Circuit 44 can transmit to the nearby device the log data, and may also repeatedly transmit transient values of the calculated flow rate. After transmitting the log data to the nearby device or the remote location, the log data can optionally and preferably be deleted from circuit 44 to save on storage.

In cases in which there is no communication with the cloud or remote computer and circuit 44 does not calculate the flow rate, circuit 44 can transmit the measured pressure difference value to the nearby device. The nearby device can either calculate the flow rate using the database 70 by its own CPU, or it can store the received pressure difference value and transmit it to the cloud computing facility or remote computer at a later time for calculating the flow rate.

The method ends at 16.

The dimensions of pipe section 22 are preferably selected based on the expected flow rates within the flow channel. For example, when the expected flow rate is from about 5 m ³ /h to about 30 m ³ /h or from about 14 m ³ /h to about 20 m ³ /h, the dimensions of pipe section 22 are preferably selected such that the pressure difference across segment 24, is from about 1 mbar about 10 mbar. As a representative example for these embodiments, the diameter /241, of pipe section 22 at end 24b of segment 24 (FIG. 2B) can be about 110 mm, and the diameter d^Aa of pipe section 22 at end 24a of segment 24 (not shown) can be about 75 mm. When the expected flow rate is from about 40 m ³ /h to about 80 m ³ /h, the dimensions of pipe section 22 are preferably selected such that the pressure difference across the passage is from about 1 mbar to about 6 mbar. As a representative example for these embodiments, the diameter 6?24b of pipe section 22 at end 24b of segment 24 can be about 160 mm, and the diameter of pipe section 22 at end 24a of segment 24 can be about 125 mm

When the expected flow rate is from about 80 m ³ /h to about 120 m ³ /h, or from about 70 m ³ /h to about 180 m ³ /h, the dimensions of pipe section 22 are preferably selected such that the pressure difference across the passage, is from about 1 mbar to about 7 mbar. As a representative example for these embodiments, As a representative example for these embodiments, the diameter/241, of pipe section 22 at end 24b of segment 24 can be about 200 mm, and the diameter of pipe section 22 at end 24a of segment 24 can be about 160 mm

FIGs. 3 A and 3B are schematic illustrations of a drip irrigation system 50 employing the flow rate measuring system 20 according to some embodiments of the present invention. System 50 comprises one or more irrigation dripping pipes 54, each having dippers 56 distributed along its length. System 50 also comprises a distributing line 52 receiving irrigation water from a water source 64 (shown only in FIG. 3A), such as, but not limited to, a water tank or the like. Irrigation dripping pipes 54 are connected to the distributing line 52, optionally and preferably at an angle (e.g., a right angle) thereto, such that each irrigation pipe 54 receives a flow of water from distribution line 52, and discharges the water through drippers 56. The distributing line 52, dripping pipes 54, and drippers 56 are deployed in a field 58. Flow rate measuring system 20 is preferably placed before the first irrigation pipe 54 that is connected upstream the distribution line 52, for example between the water source 64 and the distribution line 52, as schematically illustrated in FIG. 3A. Alternatively, flow rate measuring system 20 can be connected further downstream distribution line 52 as schematically illustrated in FIG. 3B.

In a preferred embodiment of the invention, the irrigation dripping pipes 54 are placed on a ground that is inclined, in a manner that dripping pipes 54 are also inclined at the same slope as the ground or at a different (typically smaller) slope. The advantage of this embodiment is that the water pressure in the pipe is generated, at least in part by the gravitation force. The present embodiments also contemplate configurations in which the irrigation dripping pipes 54 are generally horizontal (e.g., within 5% deviation), e.g., placed on a ground that is not inclined.

In some embodiments of the present invention the water is delivered to line 52 at a pressure of at most about 120 mbar (e.g., from about 5 to about 150 mbar), or at most about 90 mbar (e.g., from about 5 to about 90 mbar), or at most 80 mbar (e.g., from about 5 to about 80 mbar), or at most 70 mbar (e.g., from about 5 to about 70 mbar), or at most 60 mbar (e.g., from about 5 to about 60 mbar), or at most 50 mbar (e.g., from about 5 to about 50 mbar), or at most 40 mbar (e.g., from about 5 to about 40 mbar). The Inventors found that conventional flow meters are not suitable at such low pressures, since the amount of pressure loss across these conventional flow meters is comparable to the nominal pressure within distributing line 52. The Inventors have therefore devised flow rate measuring system 20, which can be used in irrigation systems such as system 50.

Preferably, distributing line 52 is generally horizontal, and flow rate measuring system 20 is placed, preferably, but not necessarily, also horizontally, in fluid communication with distributing line 52. For example, pipe section 22 (not explicitly shown in FIGs. 3A-B, see FIG. 2A), can be introduced to interconnect between two sections of distributing line 52.

In some cases, the largest cross-sectional diameter of pipe section 22 of system 20 is less than the cross-sectional diameter of distributing line 52, in which case the connection between the ends of pipe section 22 and distributing line 52 are by means of pipe fitting adaptors 60 (not shown, see FIG. 5). To reduce pressure loss at the connections between pipe section 22 and line 52, the pipe fitting adaptors preferably provides gradual diameter changes. This can be done by a telescopic series 62 of pipe fitting adaptors provide step-wise, or both gradual and step-wise diameter changes (FIG. 5).

As a representative example, consider a situation in which the diameter of line 52 is about 150 mm, and the largest diameter of pipe section 22 is about 110 mm In this case, a telescopic series 62 of pipe fitting adaptors can be used, in accordance with the embodiments illustrated in FIG. 5. For example, adaptor 60c can be tapered from 110 mm to 125 mm, adaptor 60b can have a uniform cross-section, about 125.5 mm in diameter, and adaptor 60a can be tapered from 125 mm to 150 mm

Irrigation pipes 54 can be made of any suitable material known in the art to operate normally to withstand pressure of at least 1 bar, to withstand accidental pressures as a result of loads generated, for example, by overridden wheels of a vehicle, and/or to withstand weather conditions, such as rain, or high temperatures typically caused from heat generated by the sun. For example, suitable materials may be polyethylene, polypropylene, polyvinylchloride and other thermoplastic materials. Typically, irrigation pipe 54 has a diameter of from about 12 mm and to about 60 mm, and length of from about 5 m to about 800 m

Optionally, the liquid supplied to line 52 is a natural water that contains at least M mg per liter of total suspended solids. In some embodiments of the present invention the water is not filtered prior to entering irrigation pipe 54 so that it still contains M mg per liter of total suspended solids within pipe 54 and within the drippers 56. Typical values of M include, without limitation, at least 70, or more preferably at least 80, or more preferably at least 90, or more preferably at least 100, or more preferably at least 110, or more preferably at least 120, or more preferably at least 130. Alternatively, M can be less than 50.

As used herein the term “about” refers to ± 10 %

The terms "comprises", "comprising", "includes", "including", “having” and their conjugates mean "including but not limited to".

The term “consisting of’ means “including and limited to”.

The term "consisting essentially of' means that the composition, method or structure may include additional ingredients, steps and/or parts, but only if the additional ingredients, steps and/or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure.

As used herein, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" may include a plurality of compounds, including mixtures thereof.

Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging/ranges between” a first indicate number and a second indicate number and “ranging/ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements. Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. It is the intent of the applicants) that all publications, patents and patent applications referred to in this specification are to be incorporated in their entirety by reference into the specification, as if each individual publication, patent or patent application was specifically and individually noted when referenced that it is to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting. In addition, any priority documents) of this application is/are hereby incorporated herein by reference in its/their entirety.