Abstract:
A water provisioning device for use with an irrigation channel for providing water into an irrigation pipe. The water provisioning device comprises a primary reservoir adapted to maintain water up to a predetermined level and comprising a primary outlet adapted for being brought in fluid communication with the irrigation pipe. The system further comprises at least one primary inlet tube in the form of a siphon tube with a proximal end manually insertable into said channel for drawing water therefrom and a distal end adapted for the initiation of suction within the tube and for the disposition in said reservoir at least after the suction has been initiated, to supply said water thereto.

Description:
FIELD OF THE INVENTION 
   This invention relates to devices adapted to supply water to irrigation systems, in particular to low-pressure irrigation systems. 
   BACKGROUND OF THE INVENTION 
   In many developing nations, irrigation of crops is performed as cheaply as possible, due to lack of funds and technical know-how. Typically, water for irrigation of a field is brought to the field in a raised irrigation channel, which is usually open and in the shape of a long trough. A sluice gate is opened adjacent to the field, flooding it and saturating the soil thereof. Alternatively, a tube may be used to siphon water onto the field. Besides the lack of control of the amount of water to be supplied to the field, this method of irrigation may lead to introduction of impurities in the water to the field, adversely affecting soil and crop quality, compacting of the soil, oversupply of water to the field, and introduction of disease to the soil. 
   Often, besides the lack of funds and technical know-how necessary to obtain and operate a conventional sophisticated higher pressure micro-irrigation system, external power sources are not typically available in the fields which would be necessary to run such a system, even if it were available. 
   SUMMARY OF THE INVENTION 
   According to the present invention, there is provided a water provisioning device for use with an irrigation channel for providing water into an irrigation pipe. The water provisioning device comprises a primary reservoir adapted to maintain water up to a predetermined level and comprising a primary outlet adapted for being brought in fluid communication with the irrigation pipe. The system further comprises at least one primary inlet tube in the form of a siphon tube with a proximal end manually insertable into said channel for drawing water therefrom and a distal end adapted for the initiation of suction within the tube and for the disposition in said reservoir at least after the suction has been initiated, to supply said water thereto. 
   By providing such a device, the amount of water supplied to a field from an irrigation channel may be controlled using only the potential energy of the water therein, such as due to its differential height, with no need for external energy sources. 
   The irrigation pipe may constitute a part of a low-pressure irrigation system. 
   The primary inlet tube may be rigid and have a bent, e.g. U-like, shape or it may comprise at least one flexible portion, allowing the tube to take a first, suction initiation position, and a second, water supply position. 
   Thus, the distal end of the primary inlet tube may be provided with a filter. Since the distal end is disposed substantially within the primary reservoir and may further be maintained below the level of water therein, the filter is protected, thereby extending its useful life. 
   The primary outlet of the primary reservoir may be fitted with a strainer on an upstream end thereof facing the interior of the reservoir for preventing, inter alia, a filter from being drawn into the primary outlet. The strainer may be formed integrally with the primary outlet. 
   The water provisioning device may further comprise a secondary reservoir adapted to hold a predetermined amount of water and comprising a secondary outlet, which may be in the form of a siphon tube, adapted for bringing the secondary reservoir into fluid communication with the primary reservoir. The secondary reservoir further comprises at least one secondary inlet tube in the form of a siphon tube with a proximal end manually insertable into said channel for drawing water therefrom and a distal end adapted for the initiation of suction therewithin and for the disposition in said secondary reservoir at least after the suction has been initiated, to supply said water thereto. The secondary reservoir may be used to provide fertigation to the water in the primary reservoir during irrigation. 
   The secondary outlet may be in the form of an additional siphon tube having tube with a proximal end manually inserted into said reservoir for drawing water therefrom and a second end adapted for the initiation of suction therewithin and for the disposition in said primary reservoir at least after the suction has been initiated, to supply water from the secondary reservoir into the primary reservoir. 
   The distal end of the at least one secondary inlet tube and/or secondary outlet may be provided with a filter. 
   According to another aspect of the present invention, there is provided a siphon tube for use with an irrigation channel. The siphon tube has a proximal end adapted for manual introduction into the channel for drawing water therefrom, and a distal end adapted for connection to an irrigation pipe, the distal end comprising a filter. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of a non-limiting example only, with reference to the accompanying drawings, in which: 
       FIG. 1  is a perspective view of a water provisioning device according to one embodiment of the present invention, shown in use in conjunction with an irrigation channel and an irrigation pipe; 
       FIG. 2  is a perspective view of a primary reservoir of the water provisioning device illustrated in  FIG. 1 ; 
       FIG. 3A  is a perspective view of a primary outlet insert of the primary reservoir illustrated in  FIG. 2 ; 
       FIGS. 3B and 3C  are cross-sectional views of the primary reservoir illustrated in  FIG. 2  with other examples of primary outlets; 
       FIG. 4  is a perspective view of a primary inlet tube of the water provisioning device illustrated in  FIG. 1 ; 
       FIG. 5  is a perspective view of the water provisioning device in accordance with another embodiment of the present invention; 
       FIG. 6  is a perspective view of a secondary inlet tube of the device illustrated in  FIG. 5 ; 
       FIG. 7  is a perspective view of an additional tube of the device illustrated in  FIG. 5 ; 
       FIG. 8  is a perspective view of a water provisioning system according to still further embodiment of the present invention; 
       FIG. 9  is a cross sectional view of a tube with a flap-valve attached thereto, used to assist in establishing suction in the tube; and 
       FIG. 10  is a cross sectional view of a tube with a larger diameter tube, used to assist in establishing suction therein. 
   

   DETAILED DESCRIPTION OF EMBODIMENTS 
     FIG. 1  illustrates one example of a water provisioning device, according to the present invention, generally indicated at  10 , which is adapted for use with an irrigation channel  12 . The water provisioning device is shown connected to an irrigation pipe  14 , which constitutes a part of a low-pressure irrigation system (not illustrated), e.g. such as disclosed in WO 04/098269, corresponding to US 2004/222321, of the Applicant, the contents of which are incorporated herein by reference. 
   The water provisioning device  10  comprises a primary reservoir  16  and a primary inlet tube  18  having a proximal end and a distal end (not seen in  FIG. 1 ). The primary reservoir  16  is further provided with wheels  17 , in order to facilitate quick relocation of the water provisioning device  10  by a single user. 
   The primary reservoir  16 , illustrated separately in  FIG. 2 , may be any receptacle which is open on top and which can hold liquid, such as for example a 360 liter plastic garbage bin as illustrated, and it may also be a metal tank or drum, or a concrete trough. The primary reservoir  16  is has a primary outlet opening (not seen) with a upstream and downstream outlet members  21   a  and  21   b , respectively, mounted on the reservoir on two sides of the opening, to constitute a primary outlet thereof generally indicated at  20 . 
   The downstream outlet member  21   b  is formed with a flange  22  adapted for sealing engagement to the wall of the primary reservoir, and a nipple  24  adapted for connection thereto of the irrigation pipe  14 . 
   As best seen in  FIG. 3A , the upstream outlet member  21   a  is formed with a second flange  23  adapted to sealingly engage the interior side of the wall of the primary reservoir  16  and located opposite the flange  22 . The two flanges  22 ,  23  are connected to one another with bolts  26  which pass through the wall of the primary reservoir and the flanges around the outlet opening. The upstream outlet member  21   a  is provided with a strainer  25 . 
     FIGS. 3B and 3C  illustrate an alternative example of the primary outlet  20  which is now formed from a rigid tube  19  mounted in the primary reservoir  16  so as to substantially extend between two opposite sides thereof and to preferably project from the primary outlet opening designated at  15  in  FIG. 3B . A plurality of apertures  70  are formed in the rigid tube  19 , so that the outlet includes a strainer integral therewith, as explained below. The apertures are formed such that they are all on one half of the circumference thereof, and they all lie within a length d on the rigid tube  19 , which is no larger than the interior distance between the sides of the primary reservoir  16 . The irrigation pipe  14  (not illustrated in  FIG. 3B  or  3 C) is fitted to open end  74 . 
   The tube may be selected such that it is longer than one dimension D of the primary reservoir  16  between the two opposite sides to project from one of them. It may further be adapted to project from both sides, in which case an additional outlet opening is formed. The tube may be closed at one end, or open on both ends, in which case a cap  72  (seen in  FIG. 3C ) is fitted to one of the ends to close it. 
   The primary outlet opening  15  is sized so as to snuggly receive the rigid tube  19 . Grommets  68  may be provided within the primary outlet opening  15 , in which case the grommets are sized so as the snuggly receive the rigid tube  19 , and the primary outlet opening is sized so as to receive the grommets. 
   It will be appreciated that while the outlet  19  described with reference to  FIG. 3B  passed through two opposite walls of the primary reservoir  16 , this is not required. Alternatively, it may be inserted through a single hole in one sidewall. However, the former example results in a more stable outlet. 
   As illustrated in  FIG. 4 , the primary inlet tube  18  is substantially U-shaped, and it has a proximal portion  29 , with a proximal end  30 , a distal portion  31  with a distal end  32  and an intermediate portion  36  therebetween, which may be flexible to facilitate moving of the proximal portion  29  and the distal portion  31  of the inlet tube  18  independently of one another. Fitted to the distal end  32  is a filter bag  34 , whose filtering ability is selected based on the apertures in downstream irrigation devices (not shown) via which water exits the irrigation pipe. 
   Reverting to  FIG. 1 , in use, the primary reservoir  16  is placed adjacent or nearby to the irrigation channel  12  and the primary outlet tube  18  is mounted thereon so that its distal end  32  is disposed within the reservoir in such a position that the filter bag  34  is spaced from the primary outlet  20 , whose strainer  25  prevents the filter bag  34  from being pulled into the primary outlet  20 . The same effect can be realized in the example of the primary outlet  20  illustrated in  FIGS. 3B and 3C . Due to the apertures  70  thereof facing downward, water may enter the tube while the filter bag is prevented from getting drawn therein. 
   It will be appreciated that the primary reservoir  16  may be placed several meters away from the irrigation channel  12  is desired or necessary, as long as the distance does not prevent use of the water provisioning device  10 . However, in order to prevent overflow, the height of the primary reservoir  16  must be above the maximum water level in the irrigation channel  12 . 
   When needed, the proximal end  30  of the primary inlet tube  18  is submerged within the water in the channel, and suction is initiated at the distal end  32  of the primary inlet tube, converting the tube into a siphon tube, via which water flows into the reservoir  16  under the influence of the suction. As the primary reservoir  16  fills, the irrigation pipe  14  is supplied with water via the primary outlet  20 . In order to stop the flow of water, the proximal end  30  of the primary inlet tube  18  is lifted from the water in the channel. 
   Suction may be initiated at the distal end of the primary inlet tube in any appropriate way, which is facilitated by the flexibility of the intermediate portion  36 . Thus, when initiating the suction, the proximal end  30  of the proximal portion  29  of the inlet tube  18  may be positioned within the irrigation channel  12  while the distal end  32  of the distal portion  31  is free to move. When breaking the suction, the distal end  32  may be held within the primary reservoir  16  while the proximal end  30  is lifted from the irrigation channel  12 . 
   One example of how suction may be started is by submerging the entire inlet tube  18  below the surface of the water in the irrigation channel  12 . Both the distal end  32  and the proximal end  30  are covered by the user&#39;s hands, who then places the distal end in the primary reservoir  16 . The two ends are then uncovered. 
   Another example is by using the push-pull method. The proximal end  30  is pushed and pulled under the surface of the water, while the distal end  32  is held in the water. During the pushing, the proximal end  30  is uncovered, and during the pulling, it is covered. The resulting vacuum along with the inertia of the water induces suction within the tube. In addition, a valve, such as a flap valve  60  as illustrated in  FIG. 9 , or a ball valve (not shown), may be fitted to the proximal end  30  of the inlet tube  18 . The valve opens (indicated by the broken line in  FIG. 9 ) during the pushing, and closes during the pulling, mimicking the action of a user&#39;s hand as described above. 
   Another example of how suction may be started is illustrated in  FIG. 10 . A large-diameter tube  62  is fitted around the proximal end  30  of the inlet tube  18 . A hole  64  is made in the tube such that it is near the top of, yet still within, the large-diameter tube  62 . The large-diameter tube  62  is plunged into the water in the irrigation channel  12 . As water fills the large-diameter tube  62 , it rushes into the inlet tube  18 . In addition, the air above the water in the large-diameter tube  62  enters the inlet tube  18  via the hole  64 , thereby forming bubbles  66 . The combination of the rushing water and the rising bubbles establish flow within the inlet tube  18 . 
   In addition to the above methods, hand siphon pumps are available, such as from McMaster-Carr, USA. These are typically most appropriate for small diameter tubes. 
     FIG. 5  shows another example of a water provisioning device  10 ′ according to the present invention, which has the same primary reservoir  16  and primary inlet tube  18  as the system  10  described above, and which further comprises a secondary reservoir  38  for fertilizing the water in the primary reservoir  16  before it enters the irrigation pipe  14 . The secondary reservoir  38  is structurally similar to the primary reservoir  16 , with the exception that the secondary reservoir lacks a built-in outlet. A secondary inlet tube  40  and secondary outlet tube  42  are provided for use with the secondary reservoir  38 . The secondary inlet tube  40  is narrower than the primary inlet tube  18 , and the secondary outlet tube  42  is narrower than the secondary inlet tube  40 . As illustrated in  FIG. 6 , the secondary inlet tube  40  has a proximal end  44 , a distal end  46  and a flexible portion  47 . As illustrated in  FIG. 7 , the secondary outlet tube  42  has a proximal end  48 , a distal end  50  fitted with a filter  52 , and a flexible portion  52 . The flexible portions  47 ,  52  may be useful as described above with reference to the flexible portion  36  of the primary inlet tube  18 . 
   In use, when the primary reservoir  16  is prepared for use as described above, the secondary reservoir  38  is placed adjacent or nearby thereto and the secondary outlet tube is mounted between the two so that its distal end  50  is disposed within the primary reservoir  38 . A predetermined amount of a fertilizer, which may be in granular or liquid form, is placed within the secondary reservoir  38 . This amount may be the required total amount for the irrigation period. Alternatively, a user may add more fertilizer to the secondary reservoir  38  during use. While the proximal end  44  of the secondary inlet tube  40  is submerged within the water in the irrigation channel  12 , suction is initiated at the distal end  46  of the secondary inlet tube in any appropriate way, converting the secondary inlet tube into a siphon tube. The distal end  46  of the tube  40  is placed within the secondary reservoir  16 , with water flowing thereto under the influence of the suction. This water mixes with the fertilizer. 
   Once the secondary reservoir  38  fills with a sufficient amount of water, the proximal end  48  of the secondary outlet tube  42  is submerged therein and suction is initiated at the distal end  50  of the secondary outlet tube in any appropriate way, converting the tube  42  into a siphon tube. In this way the water/fertilizer mixture is added to the water within the primary reservoir  16  in order to be added to the irrigated water. The filter  50  prevents any impurities from being introduced to the irrigated water. 
     FIG. 8  shows a further example of a water provisioning device  10 ″ of the present invention, which is similar to the system  10 ′, with a difference between them being that instead of one primary inlet tube  18 , two such tubes are used.  FIG. 8  shows the system as if the primary and secondary reservoirs  16  and  38  are transparent to better illustrate mutual disposition of different components of the device and the heights of water level in the reservoirs relative to the ground level, at which the system is operable. In particular, with the water level in the channel  12  being at a height h 1 , the water level in the primary reservoir should be at a height h 2  lower than h 1 , and the water level in the secondary reservoir should be at a height h 3  which is lower than h 1  but higher than h 2 . 
   While the inlet tubes  18 ,  40  have been described herein as comprising two solid portions with a flexible portion therebetween, the invention is not thus limited. The inlet tubes  18 ,  40 , as well as the secondary outlet tube  42 , may be flexible along their entire lengths, depending on the method to be used for initiating suction. If the distal end  46  of the secondary inlet tube  40  is flexible, it may be coiled and placed on a pile of granular fertilizer. In this way, as the granules dissolve, and the level of fertilizer lowers, the distal end  46  of the secondary inlet tube  40  is lowered with it without becoming blocked by the granules. 
   Those skilled in the art to which this invention pertains will readily appreciate that numerous changes, variations and modifications can be made without departing from the scope of the invention mutatis mutandis.