US20060186228A1 - Irrigation dripper and pipe - Google Patents

Abstract

A dripper adapted to be bonded to interior of an irrigation pipe during manufacture and to be associated with an outlet opening in said pipe. The dripper comprises an outwardly facing surface adapted for the bonding, an outlet area associated with the surface, and at least one bulge near the outlet area. The bulge defines an outermost portion of the surface at least during manufacture of the pipe, and is adapted to form, when the dripper is bonded to the pipe, a raised outlet region in the pipe associated with the bulge. The bulge and outlet area are designed so as to form the raised outlet region suitable for at least a part of the outlet opening to be formed therein and be defined by the material of the pipe.

Description

FIELD OF THE INVENTION
• The present invention relates to irrigation drippers and, more particularly, to drippers fitted integrally in irrigation pipes, and to methods for production of such pipes.
BACKGROUND OF THE INVENTION
• Drip irrigation systems are used for providing a controlled flow of water for irrigation purposes. They typically comprise an irrigation pipe with outlet openings formed therein for the purpose of allowing outflows of water. In addition, drippers or emitters are typically provided within the pipe (in-line or integral drippers) or on the pipe (on-line drippers) in association with the outlet openings to ensure an appropriate drip rate of water therethrough.
• In-line drippers typically comprise an inwardly facing surface, which faces the interior of the pipe, an outwardly facing surface, which faces the interior of the pipe, a circumferential wall, a water inlet, which is in fluid communication with the interior of the pipe, and a water outlet, which is in fluid communication with an outlet opening in the pipe. The inlet and outlet of the dripper may be connected by a meandering channel, which is often in the form of a flow-restricting labyrinth.
• During manufacture of the pipe with the in-line drippers bonded to the interior thereof, the outlet openings must be formed in the pipe at a precise location with respect to the drippers. This requires determining the location of each dripper, and then forming the opening in a precise spot corresponding to the outlet of the dripper.
• U.S. Pat. No. 6,039,270 (US '270) discloses a solution to overcome the necessity for determining the location of drippers during manufacture. In an irrigation pipe disclosed in US '270, the drippers comprise a cylindrical end-tube projecting from their outwardly facing surface, which is used as an outlet of the dripper. Each dripper is attached to the interior of the pipe so that it is swollen at the location of the end-tube, with the end-tube and the corresponding area of the pipe projecting from the swollen portion. The production line is provided with a stationary cutting plate located at a pre-determined height relative to the pipe, which cuts the projecting part of the pipe with the end-tube, thus forming the outlet opening in the pipe at the location of the end-tube, i.e., the dripper's outlet.
SUMMARY OF THE INVENTION
• In accordance with the present invention, there is provided a dripper adapted to be bonded to interior of an irrigation pipe during manufacture and to be associated with an outlet opening in the pipe. The dripper comprises an outwardly facing surface adapted for the bonding, an outlet area associated with said surface and at least one bulge near the outlet area. The bulge defines an outermost portion of the surface at least during manufacture of the pipe, and is adapted to form, when the dripper is bonded to the pipe, a raised outlet region in the pipe associated with the bulge. The bulge and outlet area in the dripper are designed so as to form the raised outlet region suitable for at least a part of said outlet opening being formed therein and being defined by the material of the pipe.
• With the dripper designed according to the present invention, the bulge on the one hand allows for easy detection of the outlet region during manufacture of the pipe, and on the other hand allows at least part of the outlet opening to be formed solely from the material of the pipe. This allows the outlet opening to have a desired geometry, e.g., such as adapted to close, either completely or partially, when there is not sufficient water pressure in the pipe to cause an outflow of water, protecting the pipe from ingress of debris.
• According to another aspect of the present invention, there is provided an irrigation pipe having outlet openings and a plurality of drippers. Each dripper comprises an outwardly facing surface bonded to the pipe's interior, an outlet area associated with said surface in fluid communication with at least one of said outlet openings, and at least one bulge near the outlet area. The pipe comprises a raised outlet region associated with the bulge. At least a part of the outlet opening is formed in the raised outlet region and is defined by the material of the pipe.
• According to a still further aspect of the present invention, there is provided method for producing an irrigation pipe. The method comprises the steps of bonding a dripper as described above to the interior of the pipe so that a raised outlet region of the pipe is formed. The outlet area of the dripper is spaced from the raised outlet region of the pipe. The pipe is cut at the raised outlet region at a location, spaced from the bulge, to form there at least a part of an outlet opening defined by the material of the pipe.
• According to a further aspect of the present invention, there is provided a blade for producing an outlet opening in an irrigation pipe as described above. In accordance with one specific embodiment, the blade comprises a guide with a longitudinal axis, at least part of which is adapted to receive the raised outlet region of the pipe while allowing the pipe to move in a direction along the axis. The blade further comprises a cutting arrangement, which is adapted to cut the pipe at its outlet region to provide said outlet opening. The guide may have a channel disposed along the axis, and the blade may further comprise a notch at a proximal end thereof, the notch and the channel merging, and the cutting arrangement being located at this merge.
• According to a still further aspect of the present invention, there is provided a method for producing an irrigation pipe, using the above-described blade. According to this method, the pipe is passed along the axis, so that the raised portion is received within the guide. When the raised portion passes by the cutting arrangement, it is cut thereby to form the outlet opening.
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 non-limiting examples only, with reference to the accompanying drawings, in which:
• FIG. 1A is a perspective view of one embodiment of a dripper according to the present invention;
• FIGS. 1B and 1C are cross-sectional views of an irrigation pipe with the dripper ofFIG. 1A bonded thereto, taken respectively during cutting an outlet opening therein and after the outlet opening has been formed;
• FIG. 1D is a top view of a section of pipe, having the dripper ofFIG. 1A bonded interior thereto, after outlet openings have been cut therein;
• FIG. 2A is a perspective view of another embodiment of a dripper according to the present invention;
• FIGS. 2B and 2C are cross-sectional views of an irrigation pipe with the dripper ofFIG. 2A bonded thereto, taken respectively during cutting an outlet opening therein and after the outlet opening has been formed;
• FIG. 2D is a top view of a section of pipe, having the dripper ofFIG. 2A bonded interior thereto, after outlet openings have been cut therein;
• FIG. 3A is a perspective view of another embodiment of a dripper according to the present invention;
• FIGS. 3B and 3C are bonded thereto, taken respectively during cutting an outlet opening therein and after the outlet opening has been formed;
• FIGS. 3D and 3E are top views of a section of pipe, having the dripper ofFIG. 3A bonded interior thereto, after outlet openings have been cut therein;
• FIG. 4A is a perspective view of another embodiment of a dripper according to the present invention;
• FIG. 4B is a cross-sectional view of the dripper shown inFIG. 4A taken through line II-II;
• FIG. 4C is a side sectional view of the dripper shown inFIG. 4A, immediately after bonding;
• FIG. 4D shows part of the manufacture of an irrigation pipe with the dripper shown inFIG. 4A;
• FIG. 4E is a side view of a roller according to the manufacturing steps shown inFIG. 4D;
• FIG. 4F shows part of the manufacture of an irrigation pipe with the dripper shown inFIG. 4A according to another embodiment;
• FIG. 5A is a perspective view of another embodiment of a dripper according to the present invention;
• FIG. 5B is a top view of the dripper ofFIG. 5A;
• FIGS. 5C and 5D are cross-sectional views of an irrigation pipe with the dripper ofFIGS. 5A and 5B bonded thereto during and after cutting according to the present invention;
• FIG. 6A is a perspective view of the inner surface of an upper housing of a multipart dripper;
• FIG. 6B is a perspective view of the outer surface of the upper housing ofFIG. 6A;
• FIG. 6C is a top view of a lower housing of the multipart dripper;
• FIG. 6D is a perspective view of the lower housing ofFIG. 6C;
• FIG. 6E is a cross-sectional view of the assembled multipart dripper;
• FIG. 7A is a perspective view of a blade according to one embodiment of the present invention;
• FIG. 7B is a perspective view of a blade according to another embodiment of the present invention;
• FIG. 7C is a perspective view of a blade according to a further embodiment of the present invention; and
• FIGS. 7D and 7E are top views of a section of pipe after cutting using any one of the blades ofFIGS. 7A through 7C in accordance to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
• FIG. 1A illustrates anelongated dripper10 according to one embodiment of the present invention. Thedripper10 has alongitudinal axis12 and comprises an inwardly facingbase surface13 havingapertures24, an outwardly facingsurface14 extending along theaxis12, acircumferential surface11, and a meanderingchannel18 having anupstream portion18aand adownstream portion18b. The outwardly facingsurface14 is intended for bonding to the interior of an irrigation pipe (not shown inFIG. 1A). Theapertures24 are in fluid communication with theupstream portion18aof the meanderingchannel18 and with the interior of the pipe, and serve as an inlet for thedripper10. It should be noted that theapertures24 may be of any number, formed at any suitable location on the dripper, and be of any suitable design. Thedripper10 further has anoutlet area22 in fluid communication with thedownstream portion18bof the meanderingchannel18.
• Thedripper10 further comprises abulge20 near theoutlet area22. Thebulge20 is constituted by twoprojections30 parallel to theaxis12, and a connectingwall32 orthogonal thereto, whoseupper surfaces26 constitute portions of the outwardly facingsurface14.
• As shown inFIG. 1B, when the outwardly facingsurface14 together with theupper surfaces26 is bonded to the pipe, there is formed a raisedportion34 defined by theprojections30 of thebulge20, with anoutlet region35 therebetween. In operation, also illustrated inFIG. 1B, fixedblade36, either rotating or motionless, is positioned so that the raisedportion34 is engaged thereby at theregion35. As shown inFIG. 1C, aslit39 is cut into thepipe25 at theoutlet region35 of thedripper10, forming thereby anoutlet opening38 in fluid communication with theoutlet area22 of thedripper10. Theslit39, as seen from the outside of the pipe, is illustrated inFIG. 1D.
• Forming the outlet opening38 as a slit enables it to remain closed in the absence of pressure in the pipe. This helps keep dirt and other debris from clogging the opening. When water is flowing through the pipe under pressure, it opens theoutlet opening38, permitting an outflow of water therethrough.
• FIG. 2A illustrates adripper110 according to another embodiment of the present invention, which is generally similar to the dripper shown inFIG. 1A, with the exception of the structure of thebulge120. Analogous elements are given the same reference numerals as those ofFIG. 1A, however shifted by 100 (10 to110,34 to134, etc.). Thebulge120 comprises oneprojection130, which is generally parallel to theaxis112, and on one side thereof. The projection has anupper surface126, constituting a portion of the outwardly facingsurface114.
• As shown inFIG. 2B, when the outwardly facingsurface114 together with theupper surface126 is bonded to the pipe, there is formed a raisedportion134, defined by theprojection130 of thebulge120, with anoutlet region135 adjacent thereto. A fixedblade136, either rotating or motionless, is positioned so that the raisedportion134 is engaged thereby at theregion135. As shown inFIG. 2C, aslit139 is cut into thepipe125 at theoutlet region135 of thedripper110, forming thereby anoutlet opening138 in fluid communication with the outlet area122 of thedripper110. Theslit139, as seen from the outside of the pipe, is illustrated inFIG. 2D. It should be noted that by disposing theblade136 an angle, the slits are formed so as to constitute flaps.
• FIG. 3A illustrates adripper210 according to a further embodiment of the present invention, which is generally similar to the dripper shown inFIGS. 1A and 2A. Analogous elements are given the same reference numerals as those ofFIG. 1A, however shifted by 200 (10 to210,34 to234, etc.). However, the design of thebulge220 differs from those described above. According to the present embodiment, thebulge220 comprises oneprojection230, which is disposed along thelongitudinal axis212 of thedripper210.
• As shown inFIG. 3B, when the outwardly facingsurface214 together with theupper surface226 is bonded to the pipe, there is formed a raisedportion234, defined by theprojection230 of thebulge220, with anoutlet region235 adjacent thereto. A fixed blade236, either rotating or motionless, is positioned so that the raisedportion234 is engaged thereby at theregion235. As shown inFIG. 3C, slits239 are cut into thepipe225 at theoutlet region235 of thedripper210, forming thereby outlet opening238aand238b, each in fluid communication with the outlet area222 of thedripper210. Theslits239, as seen from the outside of the pipe, are illustrated inFIG. 3D. Alternatively, only one blade236 may be used, and oneslit239 is formed at each dripper, as illustrated inFIG. 3E. It should be noted that by disposing theblade136 an angle, the slits are formed so as to constitute flaps.
• FIGS. 4A and 4B illustrate another embodiment of the present invention. Once bonded to the pipe and ready for use, thedripper310 is substantially similar to thedripper210 illustrated inFIG. 3A. Analogous elements are given the same reference numerals as those ofFIG. 1A, however shifted by 300 (10 to310,34 to334, etc.). The main difference is the design of thebulge320. According to present embodiment, the dripper is formed with thebulge320 in a retracted position within a recessedportion321 of thedripper310, so that before manufacture of the pipe, the top of thebulge320 does not project above the upper facingsurface314. As such, prior to manufacture, no portion of the pipe is raised above the upper facingsurface314, as is shown inFIG. 4C.
• During manufacture, as seen inFIG. 4D, there is an additional step before cutting as described above. Once thedripper310 has been attached to the interior of the pipe, it passes between a set of rollers, comprising a rigidlower cylinder346 adapted to push, through the pipe, thebulge320 to a fully extended position, and anupper cylinder348. Theupper cylinder348 is adapted to receive thebulge320 when it is pushed to its fully extended position. This may be accomplished by the use of a cylinder made of a compressible material, or by the inclusion of a groove350 (seen inFIG. 4E) adapted to receive thebulge320. Once thebulge320 has been extended, the cutting may continue as described above with reference toFIGS. 3B and 3C.
• According to an alternative embodiment, thedripper310 as shown inFIG. 4A may be self-cutting, i.e., thebulge320 pierces an opening in the pipe upon its extension. To verify that the hole is properly formed, aprobe345, as shown inFIG. 4F, may be provided. Theprobe345 may comprise asharp edge347 at its end, useful for ensuring that the opening is properly formed.
• FIGS. 5A and 5B illustrate a further embodiment of the present invention. Analogous elements are given the same reference numerals as those ofFIG. 1A, however, shifted by 400 (10 to410,34 to434, etc.). A disk shapeddripper410 comprises an inwardly facingbase surface413 havingapertures424, an outwardly facingsurface414 extending perpendicular to anaxis412 extending orthogonal thereto through its center, and ameandering channel418 having anupstream portion418aand adownstream portion418b. The outwardly facingsurface414 is intended for bonding to the interior of an irrigation pipe (not shown inFIGS. 5A and 5B). Theapertures424 are in fluid communication with theupstream portion418aof the meanderingchannel418, and serve as inlets for thedipper410. Thedripper410 further has anoutlet area422 in fluid communication with thedownstream portion418bof the meanderingchannel418.
• Thedripper410 further comprises abulge420 near theoutlet area422. Thebulge420 is constituted by aprojection430 extending from the outwardly facingsurface414 in a direction which is parallel to theaxis412. Theprojection430 has anupper surface426, constituting a portion of the outwardly facingsurface414.
• As shown inFIG. 5C, when the outwardly facingsurface414 together withupper surfaces426 is bonded to the pipe, there is formed a raisedportion434, defined by theprojection430 of thebulge420, with an outlet region435 adjacent thereto. A fixedblade436, either rotating or motionless, is positioned so that the raisedportion434 is engaged thereby at the region435. As shown inFIG. 5D, a slit439 is cut into thepipe425 at the outlet region435 of thedripper410, forming thereby anoutlet opening438 in fluid communication with theoutlet area422 of thedripper410. Theoutlet opening438 is formed as a slit.
• FIGS. 5C and 5D show thedripper410 during and after cutting, respectively. Thebulge420 of thedripper410 is bonded to the interior of anirrigation pipe425, forming a raisedportion434 of the pipe, defined by theprojection430 of the bulge. A fixedblade436, either rotating or motionless, is positioned so that the raisedportion434 is engaged thereby at an area adjacent theprojection430. A slit is cut into thepipe425, forming thereby anoutlet opening438.
• It should be appreciated that according any of the above embodiments, the blade may optionally cut a portion of the dripper, e.g., the bulge. However, the cut made in an area of the raised portion which is largely separated from the dripper has some advantages, as described in the embodiments.
• It should be noted, that while the dripper discussed herein and shown in the corresponding figures is formed a single piece, the present invention may be carried out using a dripper comprising several pieces, as illustrated inFIGS. 6A through 6E. Adripper510 of this type typically comprises acover552, abase554, and amembrane556. Thecover552 comprises aninlet551 and a firstmeandering channel553, having anupstream portion553aand adownstream portion553b. The base further comprises anannular groove560 in fluid communication with thedownstream portion553bof the firstmeandering channel553. Thebase554 comprises anoutlet557 and a secondmeandering channel555, having anupstream portion555aand adownstream portion555b. The base further comprises acircumferential shoulder562 in fluid communication with theupstream portion555aof the secondmeandering channel555. On the side opposite the meanderingchannel555, the base554 further comprises a plurality ofbulges520 surrounding the outlet, defining therebetween anoutlet area522. The three pieces are assembled, typically prior to bonding to a pipe, as shown inFIG. 6E, so that theannular groove560 and thecircumferential shoulder562 merge to form an enclosedcircumferential passage564.
• During operation, water enters the assembleddripper510 through theinlet551. Themembrane556 forces the water to enter the firstmeandering channel553. Upon exiting the first meandering channel, the water enters the combinedcircumferential passage564, then the secondmeandering channel555. The water exits the secondmeandering channel555 at theoutlet557. Themembrane556 provides pressure compensation for the dripper. When there is an increase in pressure in the pipe, themembrane556 is forced upwardly towards theoutlet557 accordingly and restrict thereby the flow of water therethrough.
• It should be noted that according to several embodiments of the present invention described above, the dripper is bi-directional, that is, it may be bonded to the interior of the pipe wall in either direction parallel to the length of the pipe without effecting how it is cut (for example, those drippers shown inFIGS. 1A, 3A, and4A). In addition, the drippers illustrated inFIGS. 5A and 6A through6E are multi-directional drippers, i.e., they may be bonded to the interior of the pipe with any orientation with respect to the flow of water.
• FIG. 7A shows one embodiment of a blade specially adapted to cut apipe61 with a dripper bonded as described above (not seen inFIG. 7A). Ablade60 comprises twosections62 having between them alongitudinal channel64. Thesections62 are held together by a bridgingarrangement63. Thechannel64 constitutes a guide for a raisedportion34 of the pipe to pass therein during manufacture. Theblade60 further comprises atriangular notch66 at a proximal end thereof. Thenotch66 is generally symmetric about anaxis65 passing through thechannel64 and is thus useful for centering the pipe in alignment therewith. Adistal vertex68 of thenotch66 merges with thegroove62. At the location of the merge is a cuttingarrangement72, which, according to one embodiment, comprises at least onefixed cutting edge74. According to another embodiment, shown inFIG. 7B, the cutting edges74 consist of entire inwardly facingedges75 of the blade.
• According to a further embodiment, shown inFIG. 7C, the cuttingarrangement72 comprises at least onecutting edge76 which are free to rotate about apin78. The rotational movement of these cuttingedges76 is imparted by the passage of the raisedportion34 of the pipe thereby. It should be noted that the cutting edges76 may alternatively by static (i.e., non-rotating), motor driven, or reciprocating (i.e., moving alternately toward and away from the raised portion34).
• It should further be noted that although inFIG. 7C, the cutting edges76 are shown disposed above theblade60, they may be located in any suitable location including, but not limited to, below or within the surface of the blade.
• It should be noted that according to any of the embodiments described with reference to one ofFIGS. 7A through 7C, a cutting edge may be present on only one side of thechannel64.
• FIG. 7D illustrates thepipe61, as viewed from the outside after cutting by theblade60.Slits79 are formed are formed so as to constitute flaps.FIG. 7E illustrates thepipe61 as viewed from the outside when only one side of theblade60 has a cutting edge present.
• Theblade60 as described above is especially useful for embodiments wherein the raised portion may be cut from the side (e.g., to form a flap). For embodiments where the cut may be made from above (e.g., to form a slit), theblade60 may be modified so that cuttingedge74 is disposed above the raised portion.
• 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. For example, the projections need not be formed parallel to the axis or to each other.

Claims (32)

1. A dripper adapted to be bonded to interior of an irrigation pipe during manufacture and to be associated with an outlet opening in said pipe, the dripper comprising an outwardly facing surface adapted for the bonding, an outlet area associated with said surface and at least one bulge near said outlet area, said at least one bulge defining an outermost portion of said surface at least during manufacture of the pipe, and being adapted to form, when the dripper is bonded to said pipe, a raised outlet region in the pipe associated with said bulge, the at least one bulge and said outlet area being designed so as to form said raised outlet region suitable for at least a part of said outlet opening being formed therein and being defined by the material of the pipe.

2. A dripper according toclaim 1 being axi-symmetrical.

3. A dripper according toclaim 2, wherein said surface has a generally circular symmetry about an axis of symmetry perpendicular to the outwardly facing surface.

4. A dripper according toclaim 3, wherein the axis of symmetry passes in the middle of the bulge.

5. A dripper according toclaim 1, wherein the bulge is in the form of a plurality of bulging portions spaced apart.

6. A dripper according toclaim 1, wherein the surface has a generally elongated shape and a longitudinal axis.

7. A dripper according toclaim 6, wherein the bulge comprises projections on both sides of the axis, forming therebetween said outlet area.

8. A dripper according toclaim 6, wherein the bulge extends substantially parallel to the axis and offset therefrom.

9. A dripper according toclaim 6, wherein the bulge is substantially collinear with the axis, said outlet area being on at least one side of the bulge.

10. A dripper according toclaim 1, further comprising an element movable from a first position below the surface to a second position protruding therefrom, said element constituting the bulge, when in said second position.

11. A dripper according toclaim 10, wherein the bulge is adapted to pierce the pipe upon the movement during manufacture.

12. A dripper according toclaim 1, wherein said dripper comprises a housing and a membrane mounted therein.

13. An irrigation pipe having outlet openings and a plurality of drippers each comprising an outwardly facing surface bonded to the pipe's interior, an outlet area associated with said surface in fluid communication with at least one of said outlet openings, and at least one bulge near said outlet area, the pipe comprising a raised outlet region associated with said bulge, at least a part of said one outlet opening being formed in said raised outlet region and being defined by the material of the pipe.

14. An irrigation pipe according toclaim 13, wherein the outlet openings are below the top of the bulge.

15. An irrigation pipe according toclaim 13, wherein the outlet openings are at the height of the bulge.

16. An irrigation pipe according toclaim 13, wherein the opening is so formed to allow an outflow of water from the pipe due to an elevated internal pressure, and to be at least partially closed upon an absence of said pressure.

17. An irrigation pipe according toclaim 13, wherein the outlet opening is in the form a slit.

18. An irrigation pipe according toclaim 13, wherein said dripper further comprises a housing and a membrane mounted therein.

19. A method for producing an irrigation pipe, the method comprising:

(a) providing a dripper comprising an outwardly facing surface adapted for bonding to the interior of the pipe, an outlet area associated with said surface and at least one bulge near said outlet area, the at least one bulge adapted to form a raised outlet region in the pipe so that, when the dripper is bonded, said outlet area thereof is spaced from the wall of the pipe at said raised outlet region;

(b) bonding the dripper to the interior of the pipe so that the raised outlet region is formed; and

(c) cutting the pipe at the raised outlet region, at least a part of which is spaced from the bulge and is to form there an outlet opening defined by the material of the pipe.

20. A method according toclaim 19, wherein the pipe is cut using a fixed cutting arrangement.

21. A method according toclaim 19, wherein in step (b), bonding the dripper is performed prior to the formation of said raised region.

22. A method according toclaim 21, the dripper further comprising an element movable from a first position below the surface to a second position protruding therefrom, said element becoming the bulge by being moved to the second position after the bonding, whereby said raised region is formed.

23. A method according toclaim 19, wherein the raised portion of the pipe indicates to a cutting mechanism a location relative thereto, where the outlet opening is to be cut.

24. A method according toclaim 19, wherein the cut is a slit.

25. A method of according toclaim 19, further comprising:

(d) providing a blade comprising a guide having a longitudinal axis, at least a portion of which is adapted to receive the raised portion of said pipe while allowing the pipe to move along the axis; and further comprising a cutting arrangement adapted to cut said raised portion; and

(e) passing the pipe along said axis, so that the raised portion is received with the guide,

wherein the cutting arrangement is adapted to cut said raised portion.

26. A method according toclaim 25, wherein the guide comprises a channel constituting said guide and a notch at a proximal end of the blade, wherein the notch merges with the channel.

27. A method according toclaim 26, wherein the cutting arrangement is located at the merge of said notch and said channel.

28. A blade for use with a pipe having a raised portion, adapted for cutting said raised portion, said blade comprising a guide having a longitudinal axis, at least a portion of which is adapted to receive the raised portion of said pipe while allowing the pipe to move along the axis; and further comprising a cutting arrangement adapted to form a cut in said raised portion.

29. A blade according toclaim 28, further comprising a channel constituting said guide and a notch at a proximal end of said blade; wherein the notch merges with the channel.

30. A blade according toclaim 29, wherein the cutting arrangement is located at the merge of said notch and said channel.

31. A blade according toclaim 28, wherein said cutting arrangement is designed to form a slit.

32. A blade according toclaim 28, wherein the cutting arrangement comprises at least one cutting edge rotatable about an axis.

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