Irrigation pipe
An irrigation pipe formed from a sheet that is rolled into a tube about a longitudinal axis of the sheet. The pipe has a watertight layer and a fabric layer. The fabric layer comprises a first fiber arrangement including first main fibers having a first orientation and a second fiber arrangement including second main fibers having a second orientation. The first and second orientations are transverse relative to each other and to the longitudinal axis when viewed in the sheet before it is rolled.
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This invention relates to an irrigation pipe, and more specifically to multilayer irrigation pipes comprising at least a water-tight layer and a fabric layer.
BACKGROUND OF THE INVENTIONMultilayer pipes having fabric layers are known to be used in irrigation systems. Such layers are known to be formed, for example, by braiding fibers in a tubular form or by weaving fibers to form a substantially flat sheet having two opposite longitudinal ends and bending the sheet into a tubular form and bonding the opposite longitudinal ends to each other. In the latter case the fabric layer comprises weft and warp fibers, respectively aligned along the unbent sheet's longitudinal axis and a transverse axis substantially perpendicular thereto.
SUMMARY OF THE INVENTIONDuring experimentation, inventors of the present invention have found that orientation of the main or structural fibers in a fabric layer of irrigation pipes influence the extent of it's elongation along a longitudinal axis thereof due to pressure caused by fluid passing therethrough. Even a small percentage of elongation for a long irrigation pipe may result in a significant elongation length causing detrimental effects to an irrigation system to which such elongated pipe belongs. This is particularly relevant for pipes which are part of a field irrigation system, where it is desired that a pipe remain in a predisposed location in order to provide fluid to designated crops. Additionally, pipe elongation may cause undue pressure on the connection points between the elongated pipe and pipes it is connected to, potentially weakening or causing disengagement thereof. Moreover, elongation of the pipe may result in a snaking or zigzag shape of the pipe at a portion thereof, caused by the frictional interaction of the elongated portion of the pipe with the surface upon which it rests, thereby adversely affecting fluid flow therein.
For the purposes of the specification and the claims, main or structural fibers are defined as the primary load bearing fibers of a fabric layer to which they belong, and therefore constitute the main structural elements thereof. Auxiliary fibers of a fabric layer are defined as fibers primarily designed to hold main fibers with which they are associated in their orientation.
Thus, in accordance with one aspect of the present invention there is provided an irrigation pipe formed from a sheet that is rolled into a tube about a longitudinal axis of the sheet, the sheet comprising a watertight layer and a fabric layer, the fabric layer comprising a first fiber arrangement including first main fibers having a first orientation and a second fiber arrangement including second main fibers having a second orientation, wherein the first and second orientations are transverse relative to each other and to the longitudinal, axis when viewed in the sheet before it is rolled.
In accordance with another aspect of the present invention there is provided an irrigation pipe formed from a sheet that is rolled into a tube about a longitudinal axis of the sheet, the sheet comprising a watertight layer and a fabric layer, the fabric layer comprising a first fabric sub-layer and a second fabric sub-layer bonded to each other, the first fabric sub-layer having a first fiber arrangement including first main fibers having a first orientation, the second fabric sub-layer having a second fiber arrangement including second main fibers having a second orientation, the first and second orientations being transverse relative to each other and to the longitudinal axis when viewed in the sheet before it is rolled.
In accordance with yet another aspect of the present invention there is provided an irrigation pipe comprising a water tight inner layer, an outer layer and a fabric layer therebetween, the outer layer being formed with gaps that permit passage of fluid therethrough from the fabric layer.
A pipe according to any one of the above aspects of the invention may comprise a plurality of apertures formed therein at locations spaced apart along the longitudinal axis of the pipe.
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 example only, with reference to the accompanying drawings, in which:
Referring now to the drawings wherein like reference characters designate like or corresponding parts throughout several views, there is shown in
The sheet 10 is of a generally rectangular shape in a top view and comprises a first longitudinal edge 12, a second longitudinal edge 14, a first lateral edge 16, a second lateral edge 18, a top surface 20 extending between the edges (12,14,16,18), an opposing bottom surface 22 extending between the edges (12,14,16,18) and a central longitudinal axis X. The sheet 10 further comprises a layer composition generally designated as 26, having a bottom layer 28, a top layer 29 and a fabric layer designated as F sandwiched therebetween. The bottom layer 28 includes the bottom surface 22 at a bottom end thereof, the top layer includes the top surface 20 at a top end thereof and the longitudinal edges (12,14,16,18) extend along the layers (28, 29, F) to bound the layer composition at its circumference. A first longitudinal end 13 of the sheet 10 is defined adjacent the first longitudinal edge 12 and a second longitudinal end 15 of the sheet 10 is defined adjacent the second longitudinal edge 14.
In
Layer 129 may be generally similar to layer 128 (
Referring to
In
The layer 228 is a water-tight polymeric layer film or coating which serves to prevent fluid from passing therethrough (
Layer 229 may be generally similar to layer 228 (
The fabric layer 42 comprises a first fabric sub-layer 44 (
As seen in
Attention is drawn to
It is noted that that in the pipe 58, the seam 56 forms a support for each main, fiber at both its ends (12, 14) which increases the load bearing ability of each main fiber. Additionally it is noted that the pipe 58 is of a lay-flat type which when not in use under fluid pressure and/or when rolled on a reel may have a shape of a generally flat strip (not shown).
By way of an example, in an irrigation pipe 58 having either one of the layer compositions 126 or 40, optionally, the material of the inner layer 28 includes Low Density Polyethylene (LDPE), the material of the outer layer 29 includes Low Density Polyethylene (LDPE), High density Polyethylene (HDPE) and COC and the material of the fibers of the fabric layer F includes Linear Low Density Polyethylene (LLDPE) and High density Polyethylene (HDPE). The irrigation pipe 58 may have a diameter of 410 mm≥D≥8 mm and may hold an internal fluid pressure in the pipe of up to 7 bars.
The inventors performed studies of the efficiency of a pipe in accordance with the example noted above at different diameters and at different internal fluid pressures. The studies show that per unit length, a pipe 58 having an angle β of substantially 55° (i.e. 55°±2°) exhibits less axial elongation in relation to a similar pipe with an angle β other than substantially 55°. However, in some embodiments β has a value less than or equal to 70°. In some embodiments, β has a value greater than or equal to 20°. In some embodiments, β has a value greater than or equal to 20° and less than or equal to 70°. In some embodiments β has a value less than or equal to 65°. In some embodiments, β has a value greater than or equal to 45°. In some embodiments, β has a value greater than or equal to 45° and less than or equal to 65°.
Attention is now drawn to the
As seen, each main fiber (34, 36), due to its biased angle β in relation to the axis X, may be cut by the apertures 64 not more than once as opposed to a pipe having main fibers extending, inter alia, axially along the axis X (not shown) wherein the axial main fibers in the vicinity of the apertures may be cut several times. As a result, a pipe 58 with apertures 64 and main fibers at a biased angle β will incur less damage to its load bearing ability than a pipe having main fibers extending, inter alia, along the axis X.
Notably, the pipe 58 may have any number of irrigation elements attached thereto, for example, drip emitters, sprinklers, anti-rip valves, drippers, or pressure regulators may be installed using any known and appropriate method, such as heat-welding, bonding, molding etc. In addition, the apertures 64 may be small apertures which are appropriate for drip irrigation.
While the inner layer 28 of the pipe 58 is a water-tight layer, the introduction of apertures 64 or irrigation elements as described above may cause openings (not shown) through which fluid may enter the fabric layer (30, 42). The irrigation pipe 58 having the breathable outer layer 129 or 229 will allow such fluid to exit the pipe and not accumulate within the fabric layer (30, 42). This reduces damage that may occur to the sheet 10 of pipe 38 if fluid is remained trapped therein.
Those skilled in the art to which the invention pertains will readily appreciate that numerous changes, variations and modifications can be made without departing from the scope of the invention mutatis mutandis.
Claims
1. An irrigation pipe formed from a sheet that is rolled into a tube about a longitudinal axis of the sheet, the sheet comprising a watertight layer and a fabric layer, the fabric layer comprising a first fiber arrangement including first main fibers having a first orientation and a second fiber arrangement including second main fibers having a second orientation, wherein the first and second orientations are transverse relative to each other and to the longitudinal axis when viewed in the sheet before it is rolled wherein:
- the fabric layer comprises a first fabric sub-layer and a second fabric sub-layer, the first fabric sub-layer comprises the first fiber arrangement and the second fabric sub-layer comprises the second fiber arrangement; and
- the first fabric sub-layer comprises auxiliary fibers extending along the longitudinal axis and the second fabric sub-layer comprises auxiliary fibers extending along the longitudinal axis.
2. An irrigation pipe according to claim 1, wherein the fibers are made of a polyolefin.
3. An irrigation pipe according to claim 1, wherein the pipe is a lay flat pipe.
4. An irrigation pipe according to claim 1, wherein the first and second fiber arrangements are inter-woven.
5. An irrigation pipe according to claim 1, wherein the first and second orientations each form an acute angle β in relation to the longitudinal axis when measured in the sheet before it is rolled.
6. An irrigation pipe according to claim 5, wherein β has a value less than or equal to 70°.
7. An irrigation pipe according to claim 5, wherein β has a value greater than or equal to 20°.
8. An irrigation pipe according to claim 6, wherein β has a value greater than or equal to 20°.
9. An irrigation pipe according to claim 5, wherein β has a value less than or equal to 65°.
10. An irrigation pipe according to claim 5, wherein β has a value greater than or equal to 45°.
11. An irrigation pipe according to claim 9, wherein β has a value greater than or equal to 45°.
12. An irrigation pipe according to claim 5, wherein β has a value substantially equal to 55°.
13. An irrigation pipe according to claim 1, wherein the sheet is formed with at least one aperture and an irrigation element is attached to the sheet at the at least one aperture.
14. An irrigation pipe formed from a sheet that is rolled into a tube about a longitudinal axis of the sheet, the sheet comprising a watertight layer and a fabric layer, the fabric layer comprising a first fabric sub-layer and a second fabric sub-layer attached to each other, the first fabric sub-layer having a first fiber arrangement comprising first main fibers having a first orientation, the second fabric sub-layer having a second fiber arrangement comprising second main fibers having a second orientation, the first and second orientations being transverse relative to each other and to the longitudinal axis when viewed in the sheet before it is rolled; wherein:
- the first fabric sub-layer comprises auxiliary fibers extending along the longitudinal axis; and
- the second fabric sub-layer comprises auxiliary fibers extending along the longitudinal axis.
15. An irrigation pipe according to claim 14, wherein the sheet is formed with at least one aperture and an irrigation element is attached to the sheet at the at least one aperture.
16. An irrigation pipe comprising a water tight watertight inner layer, an outer layer and a fabric layer therebetween, the outer layer being formed with gaps that permit passage of fluid therethrough from the fabric layer, the watertight inner layer being devoid of gaps.
17. An irrigation pipe according to claim 16, being formed from a sheet that is rolled into a tube about a longitudinal axis of the sheet, the sheet comprising the inner, outer and fabric layers and at least one aperture that is formed therethrough.
18. An irrigation pipe according to claim 16, wherein the outer layer is in the form of a coating on the fabric layer.
19. An irrigation pipe according to claim 16, wherein the fabric layer is made of a material comprising a polyolefin.
20. An irrigation pipe according to claim 16, wherein:
- the fabric layer comprises a first fabric sub-layer and a second fabric sub-layer attached to each other;
- the first fabric sub-layer has a first fiber arrangement including first main fibers having a first orientation;
- the second fabric sub-layer has a second fiber arrangement including second main fibers having a second orientation;
- the first and second orientations are transverse relative to each other and to said a longitudinal axis of the pipe.
21. An irrigation pipe according to claim 20, further comprising:
- a layer located between the first fabric sub-layer and the second fabric sub-layer and bonding the first fabric sub-layer to the second fabric sub-layer.
22. An irrigation pipe according to claim 20, wherein:
- the first fabric sub-layer comprises auxiliary fibers extending along the longitudinal axis; and
- the second fabric sub-layer comprises auxiliary fibers extending along the longitudinal axis.
23. An irrigation pipe according to claim 14, further comprising:
- a layer located between the first fabric sub-layer and the second fabric sub-layer and bonding the first fabric sub-layer to the second fabric sub-layer.
24. An irrigation pipe according to claim 14, wherein:
- the first fabric sub-layer comprises auxiliary fibers extending along the longitudinal axis; and
- the second fabric sub-layer comprises auxiliary fibers extending along the longitudinal axis.
25. The irrigation pipe according to claim 14, further comprising an irrigation element attached to an outer surface of the irrigation pipe.
26. The irrigation pipe according to claim 16, further comprising:
- a plurality of apertures formed at longitudinally spaced apart locations along the pipe; and
- connectors attached to the pipe at the apertures.
27. The irrigation pipe according to claim 26, wherein the fabric layer and the outer layer both are made from a material comprising a polyolefin.
28. The irrigation pipe according to claim 27, wherein the fabric layer and the outer layer both include high density polyethylene (HDPE).
29. The irrigation pipe according to claim 26, wherein the outer layer is in the form of a coating on the fabric layer.
30. The irrigation pipe according to claim 26, wherein the pipe is a lay flat pipe.
31. The irrigation pipe according to claim 26, wherein the outer layer is in the form of a coating on the fabric layer.
32. The irrigation pipe according to claim 26, wherein the fabric layer comprises:
- first and second fabric sub-layers, and
- a layer located between, and bonding together, the first and second fabric sub-layers.
33. The irrigation pipe according to claim 26, wherein the pipe is formed from a sheet that is rolled into a tube about a longitudinal axis of the sheet, the sheet comprising the watertight layer, the fabric layer and the outer layer.
34. The irrigation pipe according to claim 33, wherein the irrigation pipe comprises a seam formed by overlapping first and second longitudinal ends of the sheet and bonding at least portions of the longitudinal ends of the sheet.
35. The irrigation pipe according to claim 33, wherein the irrigation pipe comprises a seam formed by bonding a first longitudinal edge of the sheet to a second longitudinal edge of the sheet.
36. The irrigation pipe according to claim 33, wherein:
- the fabric layer comprises a first fabric sub-layer and a second fabric sub-layer attached to each other, the first fabric sub-layer having a first fiber arrangement comprising first main fibers having a first orientation, the second fabric sub-layer having a second fiber arrangement comprising second main fibers having a second orientation.
37. The irrigation pipe according to claim 36, further comprising:
- a layer located between the first fabric sub-layer and the second fabric sub-layer and bonding the first fabric sub-layer to the second fabric sub-layer.
38. The irrigation pipe according to claim 36, wherein the connectors are heat-welded, bonded, or molded to the pipe.
39. An irrigation pipe comprising:
- a watertight inner layer, an outer layer and a fabric layer therebetween, the outer layer being formed with gaps that permit passage of fluid therethrough from the fabric layer, the watertight inner layer being devoid of gaps;
- a plurality of apertures formed at longitudinally spaced apart locations along the pipe; and
- connectors attached to the pipe at the apertures; wherein:
- the pipe is a lay flat pipe; and
- each of the inner, outer and fabric layers is made of a material comprising a polyolefin.
40. The irrigation pipe according to claim 39, wherein the outer layer is in the form of a coating on the fabric layer.
41. The irrigation pipe according to claim 39, wherein the fabric layer comprises:
- first and second fabric sub-layers, and
- a layer located between, and bonding together, the first and second fabric sub-layers.
42. The irrigation pipe according to claim 39, wherein the connectors are heat-welded, bonded, or molded to the pipe.
43. The irrigation pipe according to claim 39, wherein the connectors are molded to the pipe.
44. An irrigation pipe comprising:
- a watertight inner layer, an outer layer and a fabric layer therebetween, the outer layer being formed with gaps that permit passage of fluid therethrough from the fabric layer, the watertight inner layer being devoid of gaps;
- a plurality of apertures formed at longitudinally spaced apart locations along the pipe; and
- connectors molded to the pipe at the apertures; wherein:
- the pipe is a lay flat pipe.
45. The irrigation pipe of claim 44, wherein each of the inner, outer and fabric layers is made of a material comprising a polyolefin.
46. The irrigation pipe of claim 44, wherein the outer layer is breathable and configured to allow fluid to exit the pipe and not accumulate within the fabric layer.
47. An irrigation pipe comprising:
- a watertight inner layer, an outer layer and a fabric layer therebetween, the outer layer being formed with gaps that permit passage of fluid therethrough from the fabric layer, the watertight inner layer being devoid of gaps; and
- irrigation elements attached to the pipe at longitudinally spaced apart locations along the pipe; wherein:
- the pipe is a lay flat pipe.
48. The irrigation pipe of claim 47, wherein the irrigation elements are heat-welded, bonded, or molded to the pipe.
49. The irrigation pipe of claim 47, wherein each of the inner, outer and fabric layers is made of a material comprising a polyolefin.
50. The irrigation pipe of claim 47, wherein the outer layer is breathable and configured to allow fluid to exit the pipe and not accumulate within the fabric layer.
51. The irrigation pipe of claim 50, further comprising:
- a plurality of apertures formed at longitudinally spaced apart locations along the pipe; and
- connectors attached to the pipe at the apertures.
52. An irrigation pipe formed from a sheet that is rolled into a tube about a longitudinal axis of the sheet, the sheet comprising a watertight layer and a fabric layer, the fabric layer comprising a first fabric sub-layer and a second fabric sub-layer attached to each other, the first fabric sub-layer having a first fiber arrangement comprising first main fibers having a first orientation, the second fabric sub-layer having a second fiber arrangement comprising second main fibers having a second orientation, the first and second orientations being transverse relative to each other and to the longitudinal axis when viewed in the sheet before it is rolled; wherein:
- in the first fabric sub-layer, all fibers that are transverse to the longitudinal axis have said first orientation; and
- in the second fabric sub-layer, all fibers that are transverse to the longitudinal axis have said second orientation.
53. The irrigation pipe according to claim 52, wherein:
- the first fabric sub-layer comprises auxiliary fibers extending along the longitudinal axis; and
- the second fabric sub-layer comprises auxiliary fibers extending along the longitudinal axis.
54. The irrigation pipe according to claim 52, further comprising an irrigation element attached to an outer surface of the irrigation pipe.
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Type: Grant
Filed: Jul 6, 2017
Date of Patent: Nov 5, 2019
Assignee: Netafim, Ltd (Tel Aviv)
Inventor: Abed Masarwa (Taibe)
Primary Examiner: Glenn K Dawson
Application Number: 15/642,464
International Classification: F16L 11/00 (20060101); F16L 11/02 (20060101); B05B 1/20 (20060101); E03B 1/00 (20060101);