MXPA00001729A - External emitter for drip irrigation hose - Google Patents

Abstract

A drip irrigation hose comprises a tubular body enclosing a water supply passage. An external emitter is attached to the outside of the tubular body. The emitter comprises a front wall, a back wall, a side wall and a top wall defining a flow regulating channel. The emitter further comprises an outlet in at least one of the walls. The hose further comprises an inlet to the emitter. The inlet is in fluid communication with the water supply passage in the hose and the flow regulating channel in the emitter. Water flows through the water supply passage, through the inlet into the emitter, through the flow regulating channel, and out the outlet. The emitter can further comprise a purging bulb to provide a simple and efficient way for the farmer to unclog the emitter.

Description

EXTERNAL EMITTER FOR DRIP IRRIGATION HOSE FIELD OF THE INVENTION This invention relates to drip irrigation hoses, and more particularly to drip irrigation hoses having external emitters.

BACKGROUND OF THE INVENTION Drip irrigation systems have become widely used in agriculture. The drip irrigation systems supply water at a low and controlled rate to the root zone of the particular plants that are irrigated. Typically, drip irrigation is carried out by providing a low volume water outlet in each plant which allows a limited dripping of water directly to the root zone of the particular plant. Because evaporation, runoff, excess water and wetting beyond the root zone are eliminated, substantial savings in water and nutrients are obtained. In addition, drip irrigation reduces pollutants to the water table by allowing the farmer to supply only enough water and fertilizer to REF .: 32874 reaches the plants, reduces the excess water that could run and contaminate the lower water table. Emitters are used to control the flow velocity of the water coming out of the hose. The emitters can be located inside the hose (internal emitters) or on the outside of the hose (external emitters). Generally, external emitters comprise a projection that pierces and extends through the wall of the hose. The projection contains an internal passage to provide a means for water to pass from the inside of the hose to the emitter. Such emitters are generally problematic due to the generally large protruding parts protruding from one side of the hose, which makes it more difficult to wind the hose. Additionally, these emitters are subject to damage during the initial installation and tend to break. In addition, if a broken or jammed emitter is removed and replaced with a new emitter, the hole into which the projection extends tends to stretch, which increases the probability of leakage. In addition, because the projection extends into the hose, the water undergoes friction loss inside the hose. Therefore, there is a need for a problem-free issuer to solve these drawbacks. Additionally, drip irrigation hoses tend to be relatively long to be able to extend through the field. As the water moves along the hose away from the water source, the water pressure decreases. Therefore, the water pressure at the beginning of the hose (near the water source) is greater than at the far end of the hose. Because the hose's drip rate is a function of water pressure, the drip velocity at the beginning of the hose tends to be higher than at the end of the hose. The drip flow rate of such a hose is to provide the water pressure at the inlet to the emitters raised to the exponent x. In the absence of pressure compensation, the factor x is one, that is, the flow velocity is a linear function of the pressure. In the ideal case of perfect pressure compensation, the factor x is zero, that is, the flow velocity is independent of the pressure. Therefore, the factor x is a measure of the degree of pressure compensation-the smaller the factor x, the greater the pressure compensation. Generally, a hose that has a factor x of about 0.5 is considered to have some pressure compensation. A hose that has a factor x of 0.1 is considered to have a high pressure compensation capacity. Therefore, it is desirable to incorporate designs that compensate the pressure inside the hoses to reduce the effect of the pressure difference along the hose . ^? ^^^ P ^^^^^^ ^? ^^ J ^^^^^ about drip velocity, over the entire length of the hose. In addition, emitters tend to clog or clog with dirt and other debris that find their way into the emitter. Once the emitter is clogged, there are few practical alternatives to purge or clean the waste so that a flow of water suitable for the plant can be summarized. The farmer must often discard and replace the existing emitter or insert another near the seal, which can be very draining and expensive. Therefore, there is a need for an external issuer that provides the farmer or another user with a simple way to undo any waste.

BRIEF DESCRIPTION OF THE INVENTION The present invention is directed to an external emitter for use in a drip irrigation hose, which may be of the type that compensates for the pressure. The present invention solves the above drawbacks by providing a relatively inexpensive emitter design and a practical way of providing service to an emitter which is clogged with sediment or debris. In one embodiment, the invention is directed to a drip irrigation hose comprising a tubular body enclosing a water supply passage. An external emitter is attached to the outside of the tubular body. The emitter comprises a front wall, a rear wall, a side wall and an upper wall defining a flow regulation channel. The emitter further comprises an outlet in at least one of the walls. The hose also includes an entrance to the emitter. The inlet is in fluid communication with the water supply passage in the hose and the flow regulator channel in the emitter. Water flows through the water supply passage, through the entrance to the interior of the emitter, through the flow regulator channel and out of the outlet. The emitter is attached to the outside of the hose by any suitable means, preferably adhesive bonding. To obtain a seal between the emitter and the hose, the front wall, the rear wall and the side walls adhere to the hose. By means of the previous design, the emitter can be located completely outside the hose. The emitter may be of the type that compensates for the pressure or of the type that does not compensate for the pressure. In a hose mode that has an emitter that compensates for pressure, the inlet and outlet are located near the rear wall of the emitter. The emitter is similar to that described above and further comprises a flexible member having front and rear ends that divide the flow regulator channel in a first ** ath »¡^ # ^^^^^ and second parallel regions. The front end of the flexible member is joined near the front wall of the emitter, and the rear end of the flexible emitter extends near the back wall of the emitter, but without contact. When in operation, water flows into the emitter through the inlet, through the first parallel region, around the rear end of the flexible member, through the second parallel region and out of the outlet. The flexible member is preferably able to deform in the second parallel region before a pressure increase in the first parallel region, which may be on the side of the second parallel region. In another embodiment of a hose according to the invention, the emitter as described generally before further comprises a purge bulb. The purge bulb has an internal region in fluid communication with the flow regulator channel so that the pressure exerted on the purge bulb generates a local pressure to back off or expel contaminants in the emitter. 20 DESCRIPTION OF THE DRAWINGS These and other features and advantages of the present invention will be better understood with reference to the following detailed description when considered together with the accompanying drawings, wherein the same reference numerals identify similar elements, wherein: Figure 1A is a perspective view of the underside of an emitter, according to the invention. Figure IB is a perspective view of a drip irrigation hose with the emitter of Figure 1A attached to its outer surface. Figure 2A is a cross-sectional view of the hose of Figure IB. Figure 2B is a cross-sectional view of an alternative embodiment of a hose containing an external emitter according to the invention, wherein the emitter has a lower wall. Figure 3 is a schematic view of a transmitter of according to the invention. Figure 4 is a schematic view of an alternative embodiment of an emitter according to the invention. Figure 5A is a perspective view of an emitter according to the invention having a flexible chamber and a purge bulb. Figure 5B is a cross-sectional view of a hose attached to the emitter of Figure 5A. Figure 6A is a perspective view of the upper part of an emitter according to the invention having a flexible membrane and a purge bulb.

Figure 6B is a perspective view of the bottom of the emitter of Figure 6A. Figure ßC is a perspective view of the emitter according to Figure 6A showing the manner in which the bending membrane is bent before an increase in water pressure. Figure 7A is a perspective view of a drip irrigation hose having an emitter that winds around the circumference of the hose. Figure 7B is a cross-sectional view of the hose of Figure 7A.

DETAILED DESCRIPTION The present invention is directed to external emitters for use in drip irrigation hoses, and drip irrigation hoses having external emitters. In one embodiment, as shown in Figures 1A, IB and 2A, the emitter 10 is attached to the outside of a drip irrigation hose 20. The hose 20 comprises a generally tubular body containing a passage 22 for supplying water therein. The emitter 10 shown in FIGS. 1A, IB and 2A is a single-body emitter, that is, a one-piece emitter forming an inseparable assembly. Examples of single body emitters are described in United States Patent Application No. 09 / 112,886 filed July 9, 1998 entitled "Unibody Pressure-Compensating Emitter," the description of which is incorporated herein by reference. reference. The emitter 10 comprises a front wall 12, a rear wall 14, two side walls 16 and an upper wall 18. These walls, together with the wall of the hose 20 form at least one flow regulating channel 24 within the emitter 10. The emitter 10 preferably has a generally rectangular shape and is designed so that the length of the flow regulator channel 24, designated by line AA, is greater than its width, designated by line BB. The emitter 10 is placed on the hose 20 so that the lower sides of the front wall 12, the rear wall 14 and the side walls 16 are in contact with the outside of the hose. The water enters the emitter 10 through an inlet 26, which is an opening in the hose 20 placed at the end of the flow regulator channel 24 closer to the front wall 12 of the emitter. The emitter 10 further comprises at least one outlet 28 in its upper wall, near the rear wall 14, to allow the water to leave the emitter. The outlet 28 is preferably a slot outlet, but alternatively may comprise one or more orifices or any other suitable opening. In operation, water enters the emitter 10 through the inlet 26, flows through the flow regulator channel 24 and exits the emitter through the outlet 28. Alternatively, the emitter 10 may further comprise a lower wall 19, the which can be in contact with the outer wall of the hose 20, as shown in Figure 2B. In this design, the lower wall 19 contains an inlet opening 27 aligned with the inlet 26 in the hose 20 to allow water to enter the emitter 10. However, an emitter 10 with a lower wall 19 is less desirable because it requires that the inlet opening 27 of the emitter aligns with the inlet 26 in the hose 20. The flow regulator channel 24 can have any suitable configuration known to those skilled in the art. Preferably, the flow regulator channel 24 comprises at least one resistance element, that is, an element that generates resistance to flow, which in turn generates a pressure drop. Preferred resistance elements are deflectors 30 (or V-shaped pieces) that form a turbulent flow section 32. As shown in Figure 1A, the alternating deflectors 30 of the turbulent flow section 32 form a serpentine flow path. An example of such a design is described, for example, in U.S. Patent Application Serial No. 09 / 112,886 referred to above., the description of which is incorporated herein by reference. Alternatively, the flow regulator channel 24 may comprise a turbulent flow section 32 having a labyrinth-type coil path such as that described in U.S. Patent No. 4,880,167, the disclosure of which is incorporated herein by reference. as reference. In such mode, the resistance elements are the walls of the coil path. Alternatively, the resistance element may comprise a transverse wall 34 containing an orifice 36, as shown in Figure 3. A further alternative design for the resistance element, as shown in Figure 4, comprises a nozzle section, that is, a region that generates a nozzle effect by reducing the cross-sectional area of the water flow path and bypasses the flow, and thus guides the water to a narrow channel and decreases the water pressure. In the embodiment shown, the nozzle section comprises two converging side walls 38, which serve as resistance elements. The converging side walls 38 increase the velocity of the water leaving the nozzle section, which ultimately reduces the water pressure. Other designs for a nozzle section are described in the international patent application PCT / US98 / 09254, filed on May 6, 1998, the description of which is incorporated herein by reference. In the emitters 10 shown in FIGS. 3 and 4, the water flows in the direction of the arrow 40. The hoses 20 and the emitters 10 described above can be manufactured in different ways. For example, the hose 20 can be formed from an elongated strip of plastic film, which typically has a thickness of 102 to 508 μm (4-20 mils). The strip is bent longitudinally to form superimposed inner and outer longitudinal margins. A longitudinal reinforcement seals the margins. In By virtue of the longitudinal fold in the strip, the inner surface of the strip defines a water supply passage 22, which is connected to a source of water under pressure. The example of such hoses is described, for example, in U.S. Patent Nos. 4,247,051, 4,984,739, 5,282,578 and 5,522,551, the descriptions of which are incorporated herein by reference. Alternatively, the hose 20 can be a seamless tubular hose, which can be formed through an extrusion process. The hose 20 can be made of any suitable material, Preferably polyethylene or a combination of polyethylene. The product can be in the form of a ribbon or in the form of a hard hose. The emitter 10 can be manufactured from a single piece of material, preferably plastic. The materials suitable for the emitter 10 include, but are not limited to polyethylene, polypropylene, thermoplastic elastomers, silicone, rubber and polyurethane. Alternatively, the emitter can be made of two or more materials that together form a single piece, which can be obtained, for example, by injection molding. The emitter can be flexible, that is, capable of being deformed to the shape of the exterior of the hose, or it can be hard and in this way is already rounded to a certain extent to be placed sealingly on the outside of the hose. In FIGS. 5A and 5B another embodiment of an external transmitter useful in the invention is shown. The emitter 10 is similar to that described above, and has a front wall 12, a rear wall 14, side walls 16 and an upper wall 18. The inlet 26 from the hose 20 to the emitter 10 is placed near the front wall 12. Unlike the embodiment described above, however, the outlet 28 is also positioned near the front wall 12. Water enters the emitter 10 through the inlet 26 and flows between the thin flexible chamber 40 and the surface of the hose 20. The flexible chamber 40 has a front end 42 and a rear end 44. The forward end 42 contacts the forward wall 12 and the sides of the flexible chamber 40 contact the side walls 16 of the emitter. The flexible chamber 40 terminates before reaching the rear wall 14, which allows water to flow around the rear end 44 of the flexible chamber and between the flexible chamber 40 and the upper wall 18. Preferably, the flexible chamber 40 is free to float within the emitter 10. Alternatively, the flexible chamber 40 may adhere to the emitter, or the emitter may be molded so as to retain the flexible chamber in place, for example having a groove along its inner edge within which the edges of the flexible chamber are placed. In the embodiment shown, there is a section 32 of turbulent flow between the flexible chamber 40 and the upper wall 18. Similar to the embodiment described above, the turbulent flow section 32 comprises alternating deflectors. In the absence of water pressure, the flexible chamber 40 is separated from the deflectors 30, ie there is a separation between the flexible chamber and the deflectors. At low water pressure, this separation is relatively large so that part of the water flowing through the turbulent flow section 32 does not pass through the deflectors 30 as it flows through the gap between the deflectors 30 and the flexible chamber 40 . However, when pressure is exerted on the flexible chamber 40 by the water entering the emitter 10 through the inlet 26 from the main water supply passage 22, the flexible chamber 40 is compressed towards the baffles 30, which decreases the size of the separation. In this way the flow of water is restricted through the turbulent flow section 32. When the water pressure that enters the emitter 10 i-.j-bM ^. ^ í ^, ^^^^^^^ B ^ fc ^^^ lte ^^ sfe decreases later, the flexible chamber 40 moves away from the baffles 30, which increases the size of the separation and therefore the flow of water through the section 32 of turbulent flow. Upon leaving the turbulent flow section 32, water drips from the device through the outlet 28, similar to that described above. As will be recognized by those skilled in the art, the turbulent flow section 32 may be substituted in this embodiment with any other section containing one or more resistance elements as described above. The design of the flexible chamber 40 provides a pressure compensating section within the emitter 10. As used herein a "pressure compensating section" is a flow passage that adjusts the flow rate of water passing through it. in response to the water pressure in the water supply passage 22 of the hose 20 by deformation of one or more walls, which, in the embodiment shown, is the turbulent flow section 32. Preferably, the emitters obtain a factor x of 0.4 or less between 41 and 414 kPa (6 and 60 psi). More preferably, the emitters obtain a factor x of 0.35 or less, still more preferably 0.25 or less, and even much more preferable of 0.20 or less, between 41 and 414 kPa (6-60 psi). In a particularly preferred embodiment, the The emitter obtains a factor x of 0.1 or less, between 41 and 414 kPa (6-60 psi). To obtain pressure compensation, the flexible member responsive to pressure, that is, the flexible chamber 40, must be made of a material capable of being deformed into a section to compensate for pressure. Preferably, the flexible chamber 40 is manufactured from a single piece of material that is different from, and more deformable and elastic than, the materials of the emitter 10 and the hose 20. A preferred material for the flexible chamber 40 comprises a thermoplastic elastomer, for example , a thermoplastic elastomer based on polyethylene having properties similar to those of thermosetting rubber, such as metallocene. The flexible chamber 40 can also be formed of another elastomeric material having similar flexibility properties. Alternatively, the material of the flexible chamber 40 is the same as the emitting material and / or the material of the hose, but is structurally capable of being deformed sufficiently in the pressure compensation section, enough to control the flow within the emitter . For example, the thickness of the material of the flexible chamber may be less than that of the emitter material and the material of the hose, so that the flexible chamber is more deformable than the walls of the emitter and the hose. In another embodiment, the flexible chamber is made of two or more materials that together form a single piece, which can be obtained, for example, by injection molding. The emitter 10 further comprises a purge bulb 46. The purge bulb 46 generates a local back-off pressure or expels any contaminant in the emitter 10. The purge bulb 46 has a generally hemispherical shape and protrudes from the upper wall 18 of the emitter near the rear wall 14. The internal region 47 of the purge bulb 46 is in fluid communication with the channel 24 flow regulator. Therefore, when a worker pushes the purge bulb 46, the combined volume of the flow regulator channel 24 and the internal region 47 of the purge bulb 46 decrease, discharging water from the emitter 10 and therefore discharging any foreign material that causes he blocking within emitter 10, its inlet 26 or outlet 28. When the worker releases the purge bulb 46, it returns to its original shape. As will be recognized by those skilled in the art, the purge bulb 46 need not be hemispherical, but it can have any shape capable of obtaining this function. Similarly, the bleed bulb 46 need not protrude from the upper wall 18, but may protrude from any external surface of the emitter 10. For example, in the embodiment shown, the bleed bulb 46 alternately can protrude from the rear wall 14 or one of the walls 16 lateral. The purge bulb 46 can be made of the same material as the emitter or it can be made of a more flexible material, as long as the purge bulb is capable of being deformed. Another additional embodiment of the emitter of the invention is illustrated in Figures 6A, 6B and 6C. This mode also obtains pressure compensation by using a flexible member that responds to pressure within the emitter. The emitter 10 has a front wall 12, a rear wall 14, side walls 16 and an upper wall 18. The inlet 26 and the outlet 28 are both located near the front wall 12. The flow regulator channel 24 comprises a narrow and long path 48 defined on one side by a flexible membrane 50 responsive to pressure. The flexible membrane 50 has a front end 52 and a rear end 54. The forward end 52 of the flexible membrane 50 is located near the front wall 12 and the inlet 26, and the rear end 54 of the membrane is located closer to the rear wall 14. In this way, water flows into the emitter 10 through the inlet 26, passes through the narrow and long path 48, and flows around the rear end 54 of the flexible membrane 50. The water then enters a region 32 of turbulent flow, which contains deflectors 30 and a plurality of chambers 58 having pillars 60 defining a tortuous path. The turbulent flow region 32 runs substantially parallel to the narrow path 48 and is separated from this path by the flexible membrane 50. When the water pressure in the narrow path 48 is relatively low, there is a relatively large gap between the pillars 60 and the flexible membrane 50. In this way, the water flows in a relatively straight path in the region 32 of turbulent flow. However, as the water pressure in the narrow path 48 increases, the water is pressed onto the flexible membrane 50, pressing the sides towards the pillars 60 in the turbulent flow section 32, as shown in Figure 6C. The spacing between the pillars 60 and the flexible membrane 50 decreases, forcing more to flow around the pillars 60 instead of deviating from the pillars as it flows from chamber 58 to the chamber. When the water pressure decreases, the flexible membrane 50 moves away from the pillars 60, which again increases the size of the separation. After passing through a section 32 of turbulent flow, water drips from the emitter 10 through the outlet 26. As will be recognized by those skilled in the art, the turbulent flow section 32 can be substituted in this embodiment with any other section that contains one or more resistance elements as described above.

The emitter further comprises a purge bulb 46, similar to that described above. The internal region 47 of the purge bulb 46 is in fluid communication with the flow regulator channel. In the embodiment shown, the purge bulb 46 is located between the rear wall 14 of the emitter 10 and the rear end 52 of the flexible membrane 50. The internal region of the purge bulb 46 is in fluid communication with the flow regulator channel 24 via the flow passage 56. The purge bulb 46 functions similar to the purge bulb described in the previous embodiment. The emitter 10 of this mode can be molded as a single piece. Preferably, the flexible membrane 50 is made of a more flexible material than the rest of the emitter 10. For example, the flexible membrane 50 can be made of a thermoplastic elastomer, and the emitter can be made of polyethylene. Therefore, the emitter can be injection molded from two or more materials. Alternatively, the flexible membrane 50 can be made of the same material as the emitter 10, but much thinner, which allows the flexible membrane 50 to deform more easily than the emitter. Figures 7A and 7B illustrate another embodiment of a drip irrigation hose having an external emitter according to the invention. The emitter 10 comprises a front wall 12, a rear wall 14, side walls 16 and an upper wall 18. As shown in dashed lines, the emitter 10 comprises a flow regulator channel 24 having a turbulent flow section 32 similar to that described in the first embodiment. As shown in Figure 7B, the sides 5 of the emitter 10 extend completely around the hose 20 and overlap to increase adhesion of the emitter to the hose. However, the sides of the emitter do not need to extend completely around the hose 20. Alternatively, if desired, this mode can be so that the flow regulator channel 24 extends perpendicular to the water supply passage 22 in the hose 20. The emitters can be manufactured by any method known to those skilled in the art, such as molding by injection, by inserts or sequential molding. The emitters can then be attached to the exterior of the hose by any of several methods including, but not limited to, adhesive bonding, solvent bonding, thermal bonding and ultrasonic welding. The preceding description has been presented with reference to the presently preferred embodiments of the invention. Those skilled in the art and. In the technology with which this invention relates, you will appreciate that alterations and changes in the structure can be carried out described without departing significantly from the principles, spirit and scope of this invention. Accordingly, the foregoing description should not be read as pertaining solely to the precise structures described and illustrated in the accompanying drawings, but rather should be read consistent with and as support for the following claims which have their fullest and clearest scope. It is noted that in relation to this date, the best method known by the applicant to carry the In practice, said invention is the conventional one for the manufacture of the objects or products to which it refers. & i &a * Mr ~. t «< tawi »-» > - «~ -gc -". -wvtxioi fimr-mr ^ - ^ - = ^ »^» a ^^^^ & ^^^^^^ fe ^ «i ^^? I! ¿-JasS ? ^

Claims (26)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A drip irrigation hose, characterized in that it comprises: a tubular body enclosing a water supply passage; an external emitter attached to the exterior of the tubular body, the emitter comprises a front wall, a rear wall, side walls and an upper wall defining a flow regulating channel, and further comprising an outlet in at least one of the walls; and an entrance to the emitter, the entrance is in fluid communication with the water supply passage and the flow regulating channel; a purge bulb having an internal region in fluid communication with the flow regulator channel; so the water flows through the water supply passage, through the entrance to the interior of the emitter, through the flow regulating channel, and out through the outlet, and where the pressure exerted on the Purge bulb generates local pressure for retro-discharge or expulsion of pollutants in the emitter.

2. The hose according to claim 5, characterized in that the emitter is adhesively joined to the hose.

3. The hose according to claim 1, characterized in that the front wall, the 10 back wall and side walls adhere to the hose.

4. The hose according to claim 1, characterized in that the emitter is located 15 completely out of the hose.

5. The hose according to claim 1, characterized in that the flow regulating channel is defined in part by the wall of the hose.

6. The hose according to claim 1, characterized in that the flow regulating channel comprises at least one resistance element.

7. The hose according to claim 1, characterized in that the flow regulating channel comprises a region of turbulent flow.

8. The hose according to claim 1, characterized in that the flow regulating channel comprises a series of alternating deflectors.

9. The hose according to claim 10, characterized in that the inlet is located near the front wall of the emitter and the outlet is located near the back wall of the emitter.

10. The hose according to claim 1, characterized in that the inlet and outlet are both located near the rear wall of the emitter, and wherein the emitter further comprises a flexible member having front and rear ends that divide the channel flow regulator in a first and second parallel regions, 20 the front end is joined near the front wall of the emitter and the rear end extends near the back wall of the emitter, but without making contact, so the water flows inside of the emitter through the entrance, through a first parallel region, around the rear end of the sfiieS, ^^^, ^. * ^ = - ^ • _ ^ ». ^ ¿^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ for the exit.

11. The hose according to claim 10, characterized in that the flexible member is capable of being deformed in a second parallel region before an increase in pressure in the first parallel region.

12. The hose according to claim 11, characterized in that the first parallel region is on the side of the second parallel region.

13. The hose according to claim 11, characterized in that the first parallel region is above the second parallel region.

14. The hose according to claim 1, characterized in that the emitter further comprises a section that compensates for the pressure.

15. The hose according to claim 14, characterized in that the emitter acquires a factor x of 0.4 or less between 41 and 414 kPa (6-60 psi).

16. The hose according to claim 14, characterized in that the emitter obtains a factor x of 0.25 or less between 41 and 414 kPa (6-60 psi).

17. The hose according to claim 14, characterized in that the emitter obtains a factor x of 0.20 or less between 41 and 414 kPa (6-60 psi).

18. The hose according to claim 1, characterized in that the emitter further comprises a purge bulb having an internal region in fluid communication with the flow regulator channel, whereby the pressure exerted on the purge bulb generates a local pressure for retro-discharge or expulsion of pollutants in the emitter.

19. The hose according to claim 1, characterized in that the flow regulating channel in the emitter extends parallel to the water supply passage in the hose.

20. The hose according to claim 1, characterized in that the hose is in the form of a belt.

21. The hose according to claim 1, characterized in that the hose is in the form of a hard hose.

22. A drip irrigation hose, characterized in that it comprises: a tubular body enclosing a water supply passage; an external emitter attached to the exterior of the tubular body, the emitter comprises a front wall, a rear wall, side walls and an upper wall defining a flow regulating channel, and further comprising an outlet located near the rear wall of the emitter; and an entrance to the emitter, the inlet is located near the rear wall of the emitter and in fluid communication with the water supply passage and the flow regulating channel; a flexible member having front and rear ends that divide the flow regulating channel in a first and second parallel regions, the front end is attached near the front wall of the emitter and the rear end extends near the rear wall of the emitter, but without making contact, so water flows through the water supply passage, through the entrance to the interior of the emitter, through the first parallel region, around the rear end of the flexible member, through the second region parallel and out through the exit.

23. The hose according to claim 5, characterized in that the flow regulating channel comprises a turbulent flow region.

24. The hose according to claim 22, characterized in that the flexible member is capable of being deformed in the second parallel region under increased pressure in the first parallel region.

25. The hose according to claim 24, characterized in that the first parallel region 5 is on the side of the second parallel region.

26. The hose according to claim 24, characterized in that the first parallel region is above the second parallel region. Ja »^ A ^ ia-gfe ^ feS8. ^^^^ = faith» ^ 6aa6? Tefc ^^ »- ^^^^» «aisarfi ^. EXTERNAL EMITTER FOR DRIP IRRIGATION HOSE SUMMARY OF THE INVENTION A drip irrigation hose comprises a tubular body enclosing a water supply passage. 5 An external emitter is attached to the outside of the tubular body. The emitter comprises a front wall, a rear wall, a side wall and an upper wall defining a flow regulating channel. The emitter further comprises an outlet in at least one of the walls. The hose also includes 10 an entrance to the issuer. The inlet is in fluid communication with the water supply passage in the hose and the flow regulator channel in the emitter. Water flows through the water supply passage, through the entrance to the interior of the emitter, through the flow regulator channel and 15 out of the exit. The emitter may further comprise a purge bulb to provide a simple and efficient way for the farmer to unclog the emitter.