Integral dripping emitter

An extruded irrigation pipe connectable to a pressurized fluid source via a first end of the pipe, the pipe comprising drip-irrigation plug emitter mounted integrally therein during the extrusion process of the pipe. The plug emitter has an inlet in fluid communication with the first end of the pipe, a drip outlet in fluid communication with a second end of the pipe, and a flow-restricting path therebetween. The emitter plugs the pipe with respect to any fluid flow except for the flow through the flow-restricting path. The pipe is conveniently produced as a section of a continuous long pipe comprising a plurality of such sections and adapted for being cut into such sections.

FIELD OF THE INVENTION

This invention relates to emitters in drip irrigation pipelines, in particular to end or plug emitters and methods of producing the same.

BACKGROUND OF THE INVENTION

In the art of drip irrigation there are known end or plug emitters that are disposed at the outlet ends of branch irrigation pipes. They constitute plugs with some sort of pressure-reducing device providing slow trickling or dripping of water through the outlet end of the branch pipe. The branch pipe is connected by its other end to a main line supplying water under pressure.

GB 1,136,993, U.S. Pat. Nos. 3,833,176 and 3,840,209 disclose branch pipes made of resilient material with a threaded screw inserted in the outlet end of the pipe. The threads of the screw cut into the resilient walls of the branch pipe forming a restricted helical passage between the threads and the wall. The passage has great hydraulic resistance to the passing flow and thereby constitutes a pressure-reduction device. The rate of dripping may be regulated by drawing the screw deeper into the pipe or by withdrawing it.

U.S. Pat. No. 3,934,824 discloses an end emitter constituting a collapsible tube with a plurality of crimps or folds providing a sinuous path to the emitted water. The pressure reduction function of a particular end emitter is regulated by cutting off a part of the crimps.

U.S. Pat. No. 4,043,360 discloses a pressure reducing device suitable for use as an end dripper. The device has an inner cylindrical body with a plurality of transverse grooves interconnected in axial direction so as to form a tortuous flow labyrinth with the walls of a pipe where the cylindrical body is inserted.

In all the above examples, the emitters are designed for insertion in the pipe only through the end thereof.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided an extruded pipe connectable to a pressurized fluid source via a first end, the pipe comprising drip-irrigation internal plug emitter mounted integrally therein during the extrusion process of the pipe. The plug emitter has an inlet in fluid communication with the first end of the pipe, a drip outlet in fluid communication with a second end of the pipe, and a flow-restricting path therebetween. The emitter stops any flow through the pipe except for the flow through the flow-restricting path. The extruded pipe constitutes a section of a continuous long pipe comprising a plurality of such sections and adapted for being cut into such sections. The plug emitter may form a swelling at the outer surface of the pipe.

The flow-restricting path is preferably formed as a flow labyrinth defined between a labyrinth channel in the peripheral surface of the plug emitter and an adjacent wall of the pipe.

The extruded pipe may have an additional plug emitter near the original one, thereby allowing to adjust the length of the flow-restricting path by cutting off the distal emitter. For the same purpose, the pipe and the plug emitter may be adapted to be cut together.

The extruded pipe may be provided with a means for fixing its second end in suitable position relative to an irrigated plant. In this case a portion of the pipe between its second end and the drip outlet of the plug emitter may accommodate the fixing means in the form of a peg with one end tightly insertable into said portion of the pipe and a pointed second end adapted to sink in the soil. The peg may have a conduit providing fluid communication between the drip outlet and an exit disposed on peg's surface between the pipe's second end and the pointed end of the peg. Alternatively, the peg may provide a passage between the peg's surface and the internal surface of the pipe allowing a drip flow exiting from the drip outlet to leave the pipe through its second end.

According to another aspect of the present invention, there is provided a drip-irrigation plug emitter for mounting inside an extruded pipe as described above. The plug emitter may have a filter disposed upstream of the flow labyrinth. Preferably, the flow labyrinth is symmetric relative to the direction of flow therethrough to an extent that the flow inlet of the plug emitter may be used as a drip outlet and vice versa. The symmetric plug emitter may have two filters disposed at either end of the flow labyrinth.

According to a third aspect of the present invention, there is provided a method for extrusion of a continuous long pipe comprised of sections each constituting the extruded pipe described above, the method including inserting said plug emitters at predetermined intervals, during the extrusion of the pipe, so that each emitter would plug the pipe with respect to any fluid flow except for the flow path through the emitter. The method may further include cutting the long pipe into pipe sections, for example so that each section will have an end adjacent to the drip outlet of the emitter.

A network of drip irrigation lines comprising main lines and branching pipes with end emitters can be assembled in a very quick and labor-saving manner from the extruded pipes with integral plug emitters of the present invention, since the branch pipes will be manufactured with emitters in place. The individual dripping rate of each branch can be adjusted by providing more than one emitter in each pipe section and cutting off the additional emitters or a portion of the flow labyrinth together with the pipe, as needed. The pipes with plug emitters can be extruded without interruption by well-known efficient industrial methods in long continuous reels. The long pipe may be cut into sections in the moment of production or after delivery to the premises of the user.

DETAILED DESCRIPTION OF THE INVENTION

With reference toFIG. 1, there is shown a reel10of long continuous extruded pipe with drip-irrigation internal plug emitters12mounted integrally during the extrusion process of the pipe. The reel is cut into sections14, for example in positions16and18, which may be done in the process of production or after the long reel is delivered to the irrigation site, as suitable. The pipe around a plug emitter may be flush with the rest of the pipe, for example pipe34, but is preferably formed with a swelling on the outer surface, for example pipe14. A visible swelling contributes to more accurate cutting at the site. The swelling may be necessary for a narrow pipe to accommodate a larger emitter, for example with more developed flow labyrinth.

With reference also toFIG. 2, each extruded pipe section, such as section14, comprises an emitter12. The plug emitter12has an inlet20in fluid communication with a first (proximal) end22of the pipe14connectable to a pressurized source of water, such as a water supply line24, a drip outlet26in fluid communication with a second (distal) end28of the pipe, and a flow-restricting path30between the inlet20and the outlet26. The emitter12entirely closes the cross-section of the pipe so that water can flow through the pipe only by way of the flow-restricting path30. Thereby water passing through the extruded pipe14would exit from the distal end28under low pressure, in drops32.

A plurality of extruded pipe sections such as14,34and36are assembled in branching irrigation network40by connecting to the water supply line24. The assembly is labor saving and is facilitated by the fact that the plug drip emitters are already reliably integrated in the pipes in the process of production.

As shown inFIG. 2, the extruded pipe section36may comprise an additional proximal plug emitter42near the distal emitter44, thereby allowing to adjust the length of the flow-restricting path by cutting off the distal emitter44, as shown in position46. The emitter44may be made of suitable material to enable cutting it together with the pipe for the same purpose, as shown in position48.

With reference toFIGS. 3,4and5, the flow-restricting path30of the plug emitter12is preferably in the form of a flow labyrinth50defined between a labyrinth channel52in the peripheral surface of the plug emitter and an adjacent wall54of the pipe14. The plug emitter12occupies the whole cross-section of the pipe14leaving a passage for the flow only via the flow labyrinth50. As shown inFIG. 4, a plug emitter56may have a filter58disposed upstream of the flow labyrinth50. Preferably, the plug emitter with the flow labyrinth is symmetric relative to the direction of flow to an extent that the flow inlet of the plug emitter may be used as a drip outlet and vice versa, as the emitter12shown inFIG. 3. The symmetric plug emitter60may have two filters58disposed at either end of the flow labyrinth, as shown inFIG. 5. Symmetric emitters are easier to install in the pipe during the extrusion process. The body of the emitter may have notches55to facilitate cutting a portion thereof, as explained above.

With reference toFIGS. 6,7and8, the extruded pipe14may be provided with a means for fixing the distal end28in suitable position relative to an irrigated plant62. Such means may be a peg64with a brace or clamp66and blade68as shown inFIG. 6. The brace holds the end28while the blade is sunk in the soil near the plant. A portion of the pipe14between the distal end28and the drip outlet26may be used to accommodate another fixing means in the form of a peg70. The peg70has one end72tightly insertable into the end28of the pipe, and a pointed second end74adapted to sink in the soil. The peg70has a conduit76providing fluid communication between the drip outlet26and an exit78on peg's surface. The exit78may be disposed anywhere on the peg outside the pipe. As shown inFIG. 8, the peg may be in the form of a spike or a needle80having an eye82tightly sitting in the distal end28of the pipe but allowing a drip flow exiting from the drip outlet26to leave the pipe through the distal end.

The extruded pipes of the present invention are easily produced by known methods for extrusion of continuous long pipes with bypass emitters. Such method is for example disclosed in U.S. Pat. No. 3,981,452, included herein by reference, without the step of making an aperture in the pipe. The plug emitters of the present invention are inserted during the extrusion at predetermined intervals so that each emitter would stop the pipe allowing only a flow through the flow labyrinth. The method may optionally include cutting the long pipe into extruded pipe sections.

Although a description of specific embodiments has been presented, it is contemplated that various changes could be made without deviating from the scope of the present invention. For example, the flow restricting means may be in the form of a narrow opening, the labyrinth flow path may be formed entirely in the body of the plug emitter, the plug emitter may be assembled from two or more parts, etc.