NL8200904A - METHOD FOR MANUFACTURING A HOSE FOR MORE IRRIGATION PURPOSES - Google Patents

Description

-1-. 22347 / Vk / mb ï ** *

Short designation: Method for manufacturing a hose for irrigation purposes, among other things.

The invention relates to a method for manufacturing a hose for irrigation purposes or for other uses.

The object of the invention is to improve the irrigation conditions of soil using underground irrigation systems and to effect a leak or drip flow using a polyolefinic fibrous material composed of flexible plastic layers and further indicated as "plexi layer" which is flat, bonded and spun but non-woven.

Today, a number of products are available on the market that can be used in a similar system as mentioned above.

These irrigation systems are described in more detail in a number of articles and magazines. The first type of hose used in these systems is composed of an inexpensive plastic which has a number of small openings spaced appropriately across the surface. Other irrigation systems that can be laid in the ground and irrigation systems based on a leaking or dripping action have complicated distribution organs. The disadvantage of these two systems consists in that the openings or the distribution organs can be blocked by the ground or can be blocked by living organisms that occur in the ground or by particles that appear suspended in the supplied water, for example sediment, algae and such.

The first experiments were carried out with porous hoses composed of long plastic fibers, which have thousands of small holes with sizes ranging from 1 to 5 or more.

British patent 1,290,847 discloses the use of a porous and fibrous tube or hose made from a woven or non-woven structure of natural regenerated fibers or synthetic fibers. This hose is permeable to liquids and cannot be clogged by the ground or by living organisms by the water or by the particles that exist in suspension in the supplied water. In addition, this hose has a high degree of tension / elongation to absorb the internal pressure of the water necessary in irrigation systems that are laid in the ground or in case of leakage or dripping. 8200904 <; i -2- 22347 / Vk / mb systems. These piping systems also have a high resistance associated with the assembly of the pipe at the ends, for example by a thermal weld. They are also resistant to the attack by insects that occur in the ground. On the other hand, these pipes are fairly inexpensive and have a long operating time in the ground because the polyolefin plexi material is not biodegradable.

The present invention relates to a flexible hose that is permeable to liquid and is manufactured according to a method characterized in that by means of a suitable tube-shaped forming member a sheet which is of a permeable nature and of suitable dimensions is processed on such that ends, which are suitably superimposed and can be longitudinally assembled, so that an elongated tube can be formed, which tube is wrapped with another larger sheet which is not permeable in nature by means of a suitable forming member and mechanically pierced to obtain a tubular casing but without covering the ends, which remain well separated to allow fixation and longitudinal coupling of the two sheets in the bonding zone and the use of a suitable welding material. In particular, the invention relates to a hose consisting of two independent layers of different materials which form a tube with two concentric walls. The inner wall sheet which serves to control the outflowing liquid is made of a plexi-layer material which is polyolefinic in nature and non-woven. This material is characterized in that it has a porosity of 0.5-0.7, a contact angle of more than 85 ° and a Gurley-Hill porosity of 4-70 sec / 100 cm. The hose is thus composed of two different superimposed and elongated pieces, the lateral ends of which are closed by a flat and non-pierced casing.

The plexi sheet material in the form of sheets, which serves as the starting material for the hose according to the invention, is described in U.S. Pat. No. 3,442,740. This polyolefinic, plexi-shaped material can be prepared as indicated in said filament filament filament sheet, starting from a high molecular weight fiber consisting of polymers. The hydrophobic polymers are particularly suitable because they have the property of repelling water. The hydrophobic polymers are polymers that have the property 8200904 J% -3-22347 / Vk / mb that they are not wetted by water. The polymers suitable for this belong to the class of addition polymers. Among this group, the polyhydrocarbons, in particular linear polyethylene, can be mentioned in particular. Other suitable addition polymers are a mixture of linear polyethylene with lean amounts of branched polyethylene, polypropylene, polybutene, polybutylene, polybutadiene and mixtures of these products.

The sheets produced on the basis of the above-mentioned polymers are in the form of a cross-linked network of fibrous elements, which exhibit comparatively with a ribbon, the cross sections of which vary over the length of the elements. This structure can be examined by cutting the wire, and one will see some fibrous elements when one or some of these fibrous elements is pulled out and by examining the cross sections with an enlargement of 450 times.

These membrane-like elements resemble a ribbon and have a normal thickness less than 4 µm.

In the structure of the sheet, the polymeric material forms superimposed layers divided into sections. The stack is visible in the structure of the sheet, in that many of the fibrous elements are oriented in directions transverse to the other fibers in the transverse direction. This can be examined in the same manner as indicated above, namely by cutting the sheet. In addition, it is found that certain fibrous elements have a direction that crosses the cut. The cut piece is then broken in a transverse direction through 90 ° to the first cut. The fibrous threads crossing the cut are again seen. The elements are oriented in a transverse direction and have the shape of an intersection and superimposed layers. When this stacking of the 20 layers does not exist, the fibrous elements generally appear to run in the same direction in which they were made during spinning as described in Belgian Patent No. 568,524.

"One of" the "" properties; of the layer material suitable for use in the manufacture of the hose according to the invention may be indicated in the absence of regular openings or continuous connections in the sheet material. This property has been observed at 450 times magnification of the 8200904 f Z * z -4-222347 / Vk / mb sheet area. This observation has led to the assumption that apertures or pockets are present in the sheet-like material, which are interconnected in an irregular manner by serpentine paths that are interconnected. These paths give the sheet material 5 of the hose the property that it is permeable to liquids, which is an indispensable condition for water to pass through the wall at an adjustable speed. The presence of these serpentine or winding paths in the material is described in "Flow of Gases in Porous Media", Carman, Academy Press, New York, (1956).

The plyolefinic plexi layer material in the form of a sheet, with which the hose according to the invention is manufactured, is not easily wetted by water, for instance the contact angle is higher than 85 °, as can be demonstrated by the method described in "Surface Chemistry, Theory and Applications ", Bikerman, Academic Press, 15 2nd Edition, New York (1958).

The Gurley-Hill porosity of the polyolefin plexi layer material should be in the layer between 4 and 70 seconds / 100 cm and preferably at 6-30 seconds / 100 cm, which Gurley-Hill porosity is defined as being the time necessary to pass 100 cm of air 2 through 6.45 cm of material under a pressure of 9000 Pascal.

The suitable polyolefinic plexi layer material for the -2 -12 2 present hose can have a basis weight between 5.10 and 12.10 N / m o (50 and 120 g / m) and a thickness between 1 and 4 mm.

The sheet that forms the outer wall aims to protect the inner wall from the attack of insects that occur in the ground, is made of the porous and fibrous material with a non-woven structure of flaky polyester that is mechanically pierced and covered with a styrene-butadiene material.

The objects which are the object of the invention are manufactured by passing the two sheets of the different material through two concentric forming members. The sheet consisting of the polyolefinic plexi layer material is passed through the inner forming member, thereby obtaining the shape of a tube longitudinally assembled with the ends resting on one another. The non-woven sheet of flake-shaped (floqué) polyester is passed through the outer shaping member giving this sheet the same shape as the first shaping member on the first sheet, but without the ends resting, the 82 0 0 § 0 4 -5- 22347 / Vk / mb pipe formed in this way surrounds the pipe of the plexi-layer material over the whole surface, except in the upper part, by a size equal to double the part that has been put together.

Once the two sheets have been passed through the forming member 5, they are secured and welded by adding molten polyethylene thereto and passing through the assembly through a number of rollers to cool the assembly.

The invention is further elucidated with reference to the following description, reference being made to the appended drawing, in which a practical embodiment is shown as a non-limiting example. In the drawing, fig. 1 shows a top view of the hose, fig. 2 a side view of the hose, fig. 3 a cross section of the hose and fig. 4 a bottom view of the hose.

The hose obtained according to the method of the invention is composed of a sheet of plexi-layer material, of non-spun polyethylene (1) and therefore of a permeable nature, of such length and size that the material can be passed through a forming member for tubes in such a way that one obtains the longitudinal composition at the ends (4) which can be suitably brought together, as shown in Fig. 3, surrounded on the outside by a second sheet (2) consisting of a non-woven flake polyester material, which has been mechanically pierced and covered with a material consisting of styrene-butadiene. With an outer shaping member, the second sheet (2) is given the same shape as the first sheet C1), but without the ends (3) being brought together in a manner similar to the inner tube CD or surrounded by the outer tube ( 2) over the entire surface except for the top part, over a size almost equal to double the superimposed layers (4), which shape is completed by the fixation and the weld (5) of the two sheets (1) and (2) in the assembly zone with the addition of melted polyethylene.

Finally, the tube thus obtained can be passed through a number of rollers which compress and cool the tube in such a way that it takes on the flattened shape like of a ribbon, which can be inflated until the tube shape is obtained as shown in Fig. 3. when the tube is filled with a liquid or fluid, for example water, with a pressure having an appropriate operating pressure.

8200904 -6- 223 ^ 7 / Vk / mb

Once the irrigation installation is mounted under these conditions, the material of the inner sheet (1) allows water to pass through, which is finally discharged through the outer layer through the pierced outer sheet (2), which simultaneously protects the inner sheet effecting the dosing of the irrigation, which protection is obtained against insects and other means.

This tube also has other necessary qualities to be used in irrigation systems which are applied underground and in systems that have a leaking or dripping effect, which have a high resistance to the development of folds, a long operating time and a even flux. These properties are necessary to use this hose in a long length irrigation system, for example over a length of 150 m in an irrigation system of indefinite length and in a length of 300 m in a system with two fronts with equal ends. These are also necessary to ensure an even distribution of water in the soil with pipes of such length. It achieves high resistance of the joints along the length of the thermal folds or joint points of the pipes to withstand the pressures of, for example, 35,000-60,000 Pascal, which value is used in irrigation systems where the amounts of water supplied are different in dependence on the pressure of the water and where the height differences over a piece of land such as a field can effect pressures above 15,000 to 20,000 Pascal to overcome the influence of gravity on the flux in the irrigation system.

Another necessary condition is that an even flux is quickly obtained in the hose in order to achieve an even distribution of the water in the soil in those places where the hose is closest to the water source. A high resistance to attack by insects that occur in the ground must also be achieved. On the other hand, it is imperative that the tube or hose be of the desired quality for long periods of time because the hose is buried in the ground and it must be able to withstand the irrigation schedule when it is placed on the market and when it is kept in stock . This type of hose can be used for various other applications, for example to aerate the soil, to spread fertilizers, to aerate fish ponds and basins with wastewater, as well as to separate organic solvents from an aqueous mixture.

8200904 -7- 22347 / Vk / mb

The properties of the hose are demonstrated by the examples and the comparative examples listed below, where the indicated properties are found.

Example I

On a laboratory scale, a hose according to the invention was manufactured with an internal nominal diameter of 9.6 mm in accordance with the method as described above, made of a plexi-layer material of sheet-shaped polyethylene and made of a porous material with a non-woven structure of flake polyester, prepared as disclosed in U.S. Patent 3,442,740. The -2 2 sheet material with a basis weight of 6.6.10 Newton per m and _3 with a nominal thickness of 140.10 mm had a porosity of 0.6, a contact angle of 99 ° and a Gurley-Hill porosity of 10 seconds / 100 cm ^. The resistance at the joints was measured by determining the adhesion of the joint thermal fleece to each side of the tube with a recording of 2.5 mm per minute. Samples of the tube were cut to a length of 25.4 mm and folded over to measure resistance over a fold. The resistance over this fold was 3-3> 4 Newton per cm. '

Also, the flux was determined in the tube, described in this 2Q example, by placing the 1.20 m lengths of pipe sections in glass tubes that were placed slightly inclined in order to collect and measure the water passed through the wall of the tube. Unfiltered water was used for this purpose and the initial flux at 18,000 Pascal was 27 cm over 1 hour. The equilibrium flux was about 8 inches per day and occurred after about 10 hours, which rate was maintained for over 10,000 hours.

A test for accelerated hose service life was conducted at multiple pressures, as indicated in Table A, using a hose 30 cm long. At 112,000 Pascal the tube jumped after 280 hours. A half-logarithmic extrapolation of the data in Table A indicates that the operating time is normally about 2000-4000 hours with an irrigation hose installed in the ground operating at a pressure of 35-000-15,000 Pascals.

-TABLE A- 8200904 -8- 22347 / Vk / mb

TABLE A

pressure (kPa) time (hours) to break 182 42.5 5 126 190 112 280

Example II

A hose was prepared and tested in the same manner as in Example 1. The plexi layer material made of polyethylene -2 2 leen with a basis weight of 9.10 Newton per m and with a nominal thickness of 0.2 mm has a porosity of 0.6, a contact angle of 114 ° and a Gurley-Hill porosity of 12 seconds / 100 cm. The resistance at the weld or the fold of the tube, determined by measuring the adhesion of the fleece, was 140,000-175,000 Pascal.

The flux was measured according to the method described in Example 1. A nominal velocity of the flux of 15 cm per day was found at a pressure of 17,000 Pascal and it took about 20 hours to reach equilibrium flux. The accelerated service life test, which was conducted in the same manner as in Example 1, has shown that results are obtained as set forth in Table B. The hose ruptured within 710 hours at a pressure of 112,000 Pascal. A semi-logarithmic extrapolation of the data reported in Table B indicates an accelerated operating time of 6,500-4,500 hours for an in-ground irrigation hose pressurized at 14,000-35,000 Pascal.

An experiment has also been conducted with ultraviolet rays aimed at the tube to ensure that it was possible to use this hose or tube in an irrigation system by wetting the surface of the soil by leaking the hose or droplets from the surface of the hose. The tube has been exposed to ultraviolet rays using a Xenotester with a quartz filter. Weld or fold resistance has been determined after 100 and 35 hours of irradiation by proceeding according to the fleece bonding experiment. This was initially 144,200 Pascal. After 100 hours of irradiation, the weld resistance was 113-400 Pascals, and after 200 hours this resistance was 44,800 Pascals. An irradiation for 100 hours in the 820Ö904 -9- 22347 / Vk / fflb

Xenotester was equivalent to exposure for 6 months in an area of Earth with a high intensity of ultraviolet rays, for example in Arizona during the summer. This indicates that the hose has a suitable operating time which corresponds at least to the use during one season of such a drip or leak system.

TABLE B

pressure (kPa) time (hours) aruic tkraj to rupture 10 343 18 280 54 252 86 217 160 15 182 361 154 430 112 t10

An irrigation hose as described, manufactured according to known methods from a porous long fiber plastic material, has been tested according to methods mentioned in example I. The resistance or resistance of the welds of this tube, determined by the test on the adhesion of the fleece was 42,000-56,000 Pascal.

The initial flux velocity below 14,000 Pascal of this hose was more than 1.90 meters per day and the flux velocity only reached equilibrium of 0.27 meters per day after 200-300 hours. An accelerated run time test, as indicated in Table B, resulted in hose rupture that this occurred after 2.5 hours at 112,000 Pascal. Haif-logarithmic extrapolation from these data indicated that the hose operating time was less than 50 hours at 14,000 Pascal (see Table C).

TABLE C

y, /, n I Time (hours) pressure (kPa), 7 ', to break 35 112 2.5 84 6 70 10 56 12.3 8200904 -10- 22347 / Vk / mb

The plexi layer material made from polyolefins of this tube made a contact angle of 54 °. The material had thousands of straight holes that did not deviate from 10-15 in diameter.

The low contact angle, weak weld resistance, short operating time and long time required to achieve equilibrium flux from this hose indicated that this tube was not suitable for use in irrigation systems as noted above with anti-static agents.

This method is applicable independently of the desired dimensions and for all suitable materials. This method can be applied with various minor modifications provided that one does not deviate from the stated principle.

Example III

A hose was prepared as mentioned in the previous examples, wherein the porous material has a nonwoven structure of flake-shaped polyester fibers, mechanically pierced, with a thickness of 2 mm and a weight of 2.3 Newton per m.

The resistance of this tube to the attack by insects that occur in the soil has been investigated by placing this tube in a field where insects were very active. At the same time a number of hoses were placed in the same field, which were only made of a sheet of plexi-layer material of polyethylene. These tubes had been pretreated by immersing them in solutions of certain pesticides with an action against the insects as found in the soil. Once placed in the ground, the hose was again subjected to such treatment by passing a mixture of this product and water along the length of each tube over a distance of 32.40 cm. Also, a tube was made which consisted only of a sheet of plexi-layer material of polyethylene, without a treatment against the insects found in the soil, which tube was used for comparison.

All pipes are placed in the ground at a depth of 10-13 cm. Seven different insecticides have been used which are indicated in the table by numbers corresponding to the following substances: 35 No. 1 Dyphonate No. 5 Diazinon No. 2 Mocap No. 6 Rotenone No. 3 Dasinit No. 7 Chlordane.

no. 4 Euradan 8200904 -11- 22347 / Vk / mb

Number 8 was a single sheet tube of a plexi layer polyethylene material without treatment and number 9 was a double sheet tube according to the invention.

All pipes had a length of 60 meters.

5 The ground was arranged to allow four repetitions of pipes. The results obtained are shown in Table D.

10 -TABLE D- 8200904 -12- 22347 / Vk / mb? Ι. *; ^

"I

TABLE D

treated with day of last duration in number of average bulb insecticide application day weeks holes ë - -....... v. - ................................... ........ 1 —.... ..

1 Dyphonate 18-5-80 16-9-80 17 22 5 62 12 27'5 14 2 Mocap 18-5-80 16-9-80 17 -8 48 10 4 19 16 1 Dasinit 18-5-80 16- 9-80 17 20 56 14 24 15 14 6 1 Euradan 18-5-80 16-9-80 17 14 12 22 14 20 8 1 Diazinon 18-5-80 16-9-80 17 6 4 12 7'5 8 25 1 Rotenone 18-5-80 16-9-80 17 16 4 2 7) 5 8 30 1 Chlordane 18-5-80 16-9-80 17 1 4 10 4 5 3 1 - 18-5-80 16 -9-80 47 ^ in addition 24 ..... u »ins 29 34.75 ra 39 PO ^ 0 2 - 18-5-80 16-9-80 0 O tube according to 0 CD the invention 0 O 0 -fc * 0

Claims (6)

1. A method of manufacturing a hose for irrigation purposes or for other uses, characterized in that by means of a suitable tubular forming member a sheet of a permeable nature and of suitable dimensions is processed in such a way that ends suitably superposed to form an elongated tube, which tube is wound by means of an appropriate forming member with an TO other larger sheet which is impermeable in nature and mechanically pierced to form a tubular casing is obtained, but without the ends being coated, which remain well separated so as to allow a fixation and a longitudinal coupling of the two sheets in the joining zone and the use of a suitable welding material. T5 A method according to claim 1, characterized in that the tube thus obtained is passed over a series of rollers which compress and cool the tube and which give it a flat shape, corresponding to the shape of a ribbon, which can again become tubular when passed through it. a fluid is passed under a suitable pressure. 2Q A method according to claims 1-2, characterized in that the permeable sheet is composed of a polyolefin material composed of flexible plastic fibers and indicated as "plexi layer", non-woven, with a porosity between 0.5 and 0.7, a Gurley-Hill porosity of 4-70 seconds per cm 2 and a contact angle higher than 85 °. 4. Process according to claims 1-3, characterized in that p2 plexi layer material is polyolefinic with a basis weight between 5.4.10 «2 and 14.5.10 Newton Newton per m with a thickness between 0.1 and 0.3 mm. 5. A method according to claims 1-4, characterized in that the impermeable sheet is composed of a flaky polyester material, non-woven and mechanically pierced and provided with a layer of a styrene-butadiene. 6. Method according to claims 1-5, characterized in that the polyester material has a weight of 200 g / m -230 g / m and a thickness between 1 mm and 1.5 mm. Eindhoven, March 1982 8200904