TECHNICAL FIELD
[001] Embodiments of the invention relate to a drip irrigation system and
method, and in particular to a low-pressure drip irrigation system and method.
BACKGROUND
[002] Many drip irrigation systems use pressurized water sources of about 2
atmospheres and more. Distribution pipes, fittings and valves in such systems are made of strong and relatively thick plastic materials. These systems are essentially designed to be non-dependent on the field topography. However, pressure losses along their branching tubes with drip emitters are large. In order to achieve uniform dripping, special pressure-compensated emitters are used. These systems involve substantial investment costs and power consumption in operation.
[003] On the other hand, systems for flood irrigation are traditionally applied
on large areas. They include open distribution channels and branching furrows made in the fields. Since water in such systems flows only due to gravitational force, all channels and furrows are maintained with suitably designed low inclinations. Flood irrigation requires less investment costs; however, is inefficient in water consumption. Moreover, the freely flowing water causes surface erosion and salinization of soils.

SUMMARY
[004] The following embodiments and aspects thereof are described and
illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope.
[005] In an aspect of the present invention there is provided an incoming hub
for a low-pressure irrigation system, the incoming hub comprising at least one inlet for receiving incoming liquid from upstream from a siphon tube and an outlet for communicating the liquid downstream to an emitting section.
[006] In a further aspect of the present invention there is provided a low-
pressure irrigation system comprising at least one siphon tube, an incoming hub and an emitting section, wherein liquid flow entering each siphon tube is arranged to flow via a respective opening of the incoming hub into the incoming hub and onwards downstream towards the emitting section to be emitted to the ambient environment.
[007] In yet a further aspect of the present invention there is provided a method
for providing low-pressure irrigation to a field comprising the steps of: providing a low-pressure irrigation system comprising at least one siphon tube, an incoming hub and an emitting section; priming, possibly manually, each siphon tube in order to urge liquid to be powered to flow downstream therethrough under the pull of gravity; and coupling each siphon tube to the incoming hub to form a downstream flow towards the emitting section and from there to the field.
[008] In addition to the exemplary aspects and embodiments described above,
further aspects and embodiments will become apparent by reference to the figures and by study of the following detailed descriptions.
BRIEF DESCRIPTION OF THE FIGURES
[009] Exemplary embodiments are illustrated in referenced figures. It is
intended that the embodiments and figures disclosed herein are to be considered illustrative, rather than restrictive. The invention, however, both as to organization

and method of operation, together with objects, features, and advantages thereof,
may best be understood by reference to the following detailed description when read
with the accompanying figures, in which:
[010] Fig. 1 schematically shows an irrigation system in accordance with an
embodiment of the present invention, and a water source, here embodied as an open
distribution channel, for feeding the irrigation system with irrigation substances
from upstream;
[011] Fig. 2 schematically shows a partial cross-sectional view of the irrigation
system and water source illustrated in Fig. 1;
[012] Figs. 3A and 3B schematically show a possible priming procedure that
may be performed for siphoning irrigation substances from the water source via an
embodiment of a siphon tube of the irrigation system;
[013] Fig. 4 schematically shows a terminal step of the priming procedure that
includes coupling the siphon tube into liquid communication with the irrigation
system; and
[014] Fig. 5 schematically shows an additional view of the irrigation system.
[015] It will be appreciated that for simplicity and clarity of illustration,
elements shown in the figures have not necessarily been drawn to scale. For
example, the dimensions of some of the elements may be exaggerated relative to
other elements for clarity. Further, where considered appropriate, reference
numerals may be repeated within the figures to indicate like elements.
DETAILED DESCRIPTION
[016] Attention is first drawn to Fig. 1 illustrating a water source 10, here
embodied as an open distribution channel, and an irrigation system 12 according to
an embodiment of the present invention. Irrigation system 12 in this example
includes a siphon tube 14 that communicates between water source 10 and an incoming hub 16 of the system. Irrigation substances received at hub 16 are arranged to flow downstream to an emitting portion 17 of the irrigation system, here

embodied as including a distribution pipe 18 and drip irrigation pipes 20 that branch away from the distribute pipe to irrigate crops in a field.
[017] Attention is drawn to Fig. 2 illustrating a cross sectional view taken
through water source 10, incoming hub 16 and siphon tube 14 that communicates
therebetween. As seen, siphon tube 14 when in a position suitable for
communication irrigation substances downstream – is arranged to assume a generally inverted "U" shape permitting liquid to be powered to flow downstream under the pull of gravity as it is discharged through its downstream end 14d at a level lower than the origin from which it came (here the upstream end 14u of siphon tube 14 dipped in water source 10). In this example, such lower level is marked dL2, which represents a level difference between the upstream 14u and downstream 14d ends of siphon tube 14.
[018] The value of dL2 should be greater than "zero" to an extent sufficient to
overcome frictional forces (e.g. between water flowing in the siphon pipe and the pipe's internal surface) so that water will flow therethrough downstream. A siphon tube 14 suitable for manual manipulation to accomplish the "priming" process seen in Figs. 3 and 4 typically has an internal diameter of about 1 to about 2 inches (about 25 to about 50 millimeters). In a non-binding example, dL2 should be about 30 centimeters or more for water to flow downstream through such manually manipulated pipe once "primed".
[019] Upstream end 14u of siphon tube 14 is here seen located a depth dL1
beneath the upper level of the water in water source 10. In embodiments where the upstream and downstream ends 14u, 14d of siphon tube 14 are adjacently aside each other (such as in the cross section of Fig. 2) the water pressure at the downstream end of the siphon pipe is generally equal to about dL1 + dL2. In a non-binding example, such pressure exposed upon the downstream end of the siphon pipe may be about 1 meter (or the like).
[020] Attention is drawn to Figs. 3A and 3B illustrating a possible manual
priming action that may be performed in order to manually prime siphon tube 14 so

that liquid can subsequently be powered under the pull of gravity to flow downstream through the irrigation system. It is noted that other methods of priming siphon tube 14 (some of which not necessarily manual) may be performed (e.g. using pumps for such priming, etc.).
[021] In an embodiment, siphon tube 14 may be arranged to include a valve
141 immediately upstream from its downstream end 14d. While initially
maintaining valve 141 in an open state, siphon tube 14 may be manually urged to generally reciprocate slightly 'back' and 'forth', respectively, towards and away from the water source.
[022] Urging siphon tube 14 'back' and 'forth' is thus arranged to slightly
displace upstream end 14u, respectively, further into the water source and then slightly back. The urging of siphon tube 14 'back' (see Fig. 3A) is performed while maintaining the downstream end 14d of the siphon tube open, and by that permitting a dose of liquid to be primed ('primed liquid') into siphon tube 14 via its upstream end 14u.
[023] The urging of siphon tube 14 'forth' (see Fig. 3B) is performed while
maintaining (for example manually) the downstream end 14d of siphon tube
substantially closed, and by that forming under-pressure or substantial vacuum
downstream to the 'primed liquid' dose to assist in maintaining it inside of the siphon
tube during such forward motion. Additional 'back' and 'forth' cycles (as just
described) are adapted to urge additional doses of 'primed liquid' into the siphon
tube until it is sufficiently full to start siphoning liquid out of the water source.
[024] This state of initial siphoning of liquid out of the downstream end 14d of
the siphon tube is illustrated at the section provided at the right-hand side of Fig. 3B. After this state has been accomplished, valve 141 may be closed (see arrow in this section view) to maintain siphon tube 14 primed with liquid – thus forming a so-called 'primed siphon tube'.
[025] Attention is drawn to Fig. 4 illustrating a subsequent possible step of
coupling the upstream end of the 'primed siphon tube' 14 to an inlet 6 of incoming

hub 16. In this view further details of this embodiment of incoming hub 16 can be seen, including an air release tube 161 for releasing air trapped in incoming hub 16 and/or emitting section 17 as liquid rushes downstream to flow through the irrigation system.
[026] Attention is additionally drawn to Fig. 5 illustrating a schematic view of
irrigation system 12. Here, irrigation system 12 can be seen including at hub 16 possibly more than one inlet 6 (here two such inlets) for receiving incoming liquid from more than one siphon tube 14 (here respectively two siphon tubes, one for each inlet).
[027] Provision of more than one inlet 6 may be useful in accommodating
irrigation needs of varying required overall flow rates of an irrigation system. For example, an irrigation system may be required to provide a flow rate at its emitting section 17 of about 45 cubic meters per hour, while a single siphon tube 14 suitable for manual 'priming' may be suited to provide about 15 cubic meters per hour. In such case, an incoming hub 16 including three inlets 6 each communicating with a respective siphon tube 14 (each contributing 15 cubic meters per hour) may be arranged to support such overall flow rate demand (of 45 cubic meters per hour) of the irrigation.
[028] It is noted that an incoming hub 16 may be fitted with several inlets,
while not necessarily all inlets 6 are in an 'active' mode at all times. For example, in the scenario provided above, if the incoming hub 16 is provided with more than three inlets, e.g. five inlets, thus in line with the discussed scenario three of the inlets may be 'active' i.e. coupled each to a 'primed siphon tube', while the remaining two inlets may be 'in-active' i.e. not coupled to a 'primed siphon tubes'.
[029] In certain embodiments, subsequent irrigation cycles of communicating
liquid downstream through an irrigation system may be controlled via valve(s) 141. For example, an irrigation system already coupled to one or more 'primed siphon tube(s)' may commence irrigation by opening the valve(s) 141 fitted to each such tube 14. Upon completion of an irrigation cycle, the valves 141 may be closed to

terminate downstream flow of liquid via the irrigation system's emitting section. When desired, (and as long as the siphon tubes remain 'primed') a new irrigation cycle may be activated by simply opening the irrigation valve(s) 141. In certain cases, the irrigation valve(s) 141 may be electrically activated (by being e.g. of a gate valve type) to possibly remotely start and terminate an irrigation cycle. In certain the irrigation valve(s) 141 may be fitted to the openings 6 and not to the siphon tubes(s).
[030] In the description and claims of the present application, each of the verbs,
“comprise” “include” and “have”, and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of members, components, elements or parts of the subject or subjects of the verb.
[031] Further more, while the present application or technology has been
illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and non-restrictive; the technology is thus not limited to the disclosed embodiments. Variations to the disclosed embodiments can be understood and effected by those skilled in the art and practicing the claimed technology, from a study of the drawings, the technology, and the appended claims.
[032] In the claims, the word “comprising” does not exclude other elements or
steps, and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures can not be used to advantage.
[033] The present technology is also understood to encompass the exact terms,
features, numerical values or ranges etc., if in here such terms, features, numerical values or ranges etc. are referred to in connection with terms such as “about, ca., substantially, generally, at least” etc. In other words, “about 3” shall also comprise

“3” or “substantially perpendicular” shall also comprise “perpendicular”. Any
reference signs in the claims should not be considered as limiting the scope.
[034] Although the present embodiments have been described to a certain
degree of particularity, it should be understood that various alterations and modifications could be made without departing from the scope of the invention as hereinafter claimed.

We Claim :
1. An incoming hub for a low-pressure irrigation system, the incoming hub comprising at least one inlet for receiving incoming liquid from upstream from a siphon tube and an outlet for communicating the liquid downstream to an emitting section.
2. The incoming hub of claim 1 and comprising an air release tube for releasing air trapped in the incoming hub once water from upstream flows into the incoming hub via the at least one inlet.
3. The incoming hub of claim 1 or 2 and comprising more than one inlet in order to accommodate varying required flow rates of the emitting section.
4. The incoming hub of claim 3, wherein only some of the inlets are active inlets providing incoming liquid flow from upstream while one or more remaining inlets are in-active inlets not receiving liquid from upstream.
5. The incoming hub of claim 4, wherein an incoming flow rate through each inlet is FLin and the overall required flow rate of the emitting section is FLes, and wherein the number of active inlets is defined by rounding upwards the result of FLes divided by FLin to the closest positive integer.
6. A low-pressure irrigation system comprising at least one siphon tube, an incoming hub and an emitting section, wherein liquid flow entering each siphon tube is arranged to flow via a respective opening of the incoming hub into the incoming hub and onwards downstream towards the emitting section to be emitted to the ambient environment.

7. The low-pressure irrigation system of claim 6 and comprising a valve adjacent to where each siphon tube and the incoming hub communicate for controlling opening and/or closing of downstream flow from each siphon tube towards the incoming hub, wherein possibly valve(s) is(are) fitted to each siphon tube or to the opening(s) in the incoming hub.
8. The low-pressure irrigation system of claim 7, wherein valve(s) are manually or remotely activated.
9. The low-pressure irrigation system of any one of claims 6 to 8, wherein the incoming hub comprising an air release tube for releasing air trapped in the incoming hub once water from upstream flows into the incoming hub and downstream.
10. The low-pressure irrigation system of any one of claims 6 to 9, wherein the incoming hub comprising more than one inlet in order to accommodate varying required flow rates of the emitting section.
11. The low-pressure irrigation system of claim 10, wherein only some of the inlets are active inlets providing incoming liquid flow from upstream while one or more remaining inlets are in-active inlets not receiving liquid from upstream.
12. The low-pressure irrigation system of claim 11, wherein an incoming flow rate through each inlet is FLin and the overall required flow rate of the emitting section is FLes, and wherein the number of active inlets is defined by rounding upwards the result of FLes divided by FLin to the closest positive integer.
13. The low-pressure irrigation system of any one of claims 6 to 12, wherein each siphon tube is manually primed in order to urge liquid to be powered to flow

downstream therethrough under the pull of gravity as it is discharged through its downstream end.
14. The low-pressure irrigation system of claim 13, wherein each siphon tube is coupled to the incoming hub only after being primed.
15. The low-pressure irrigation system of any one of claims 6 to 14, wherein the emitting section comprises drip irrigation lines.
16. A method for providing low-pressure irrigation to a field comprising the steps of:
providing a low-pressure irrigation system comprising at least one siphon tube, an incoming hub and an emitting section;
priming, possibly manually, each siphon tube in order to urge liquid to be powered to flow downstream therethrough under the pull of gravity; and
coupling each siphon tube to the incoming hub to form a downstream flow towards the emitting section and from there to the field.
17. The method of claim 16 and comprising a valve adjacent to where each siphon tube and the incoming hub communicate for controlling opening and/or closing of downstream flow from each siphon tube towards the incoming hub, wherein possibly valve(s) is(are) fitted to each siphon tube or to the opening(s) in the incoming hub.
18. The method of claim 17, wherein valve(s) are manually or remotely activated.