Irrigation hose

Abstract: An irrigation hose provides a long life expectancy. The irrigation hose is characterized by that a plurality of flow passages are defined by partitions dividing the inside of the hose which is made of thermoplastic resin; and that each flow passage is provided with irrigation holes formed in a member of the tube portion where is in contact with outside air, that is the outer wall thereof. The irrigation hose which can provide different irrigation methods appropriate to the crops or growth stages with just one hose, without exchanging or laying multiple hoses with different irrigation methods. A film 16 is inserted between a film 12 which is made of long thermoplastic resin film with irrigation holes formed throughout at regular pitch and another film 12 which is also made of a long thermoplastic resin film with irrigation holes on both sides. One side of the film 16 is heat sealed to the lower film 12 and the other to the upper film 12, and both sides of the upper and lower films 12 along the longitudinal direction are heat sealed to one another so as to construct flow passages 29A and 29B with different formations of irrigation holes.

Description: Background of the Invention Field of Invention The present invention relates to an irrigation hose, more particularly, to an irrigation hose used for irrigation of field crops in open and green house culture. Description of the Related Art The irrigation equipment used for irrigation of field crops in open and green house culture conventionally comprises a water supply pipe laid along an end of every furrow, which is connected to a water duct coupled with a water source such as a pump, and perforated polyvinylchloride tubes, one of which ends is connected to the water supply pipe. Recently, however, instead of perforated polyvinylchloride tubes, irrigation hoses made of synthetic resin film have become commonly used as they are light, inexpensive, easy to manufacture, superior in flexibility, and easy to process, store, and remove. These irrigation hoses are generally formed by fusing longitudinally two long thermoplastic resin films at the both lateral ends thereof which are provided with many irrigation holes. Summary of the Invention The greatest cause of failure of the irrigation hoses is' obstruction of the irrigation holes. When irrigating field crops, different irrigation methods are sometimes required, such as partial irrigation to base of the products or total irrigation with spraying format, depending on the kinds of crops or their growth stages. Thus, irrigation hoses, conventionally, are exchanged for different irrigation methods depending on the crops or their growth stages, or multiple hoses of appropriate formats laid in every furrow are selected. US 3,567,134 discloses a hose with several flow passages some of which have irrigation holes. The hose may be used in the normal manner with water exiting out of the end, or for irrigation when water exits through the irrigation holes formed in one half of the circumference of the outer tubing. FR 2,600,142 discloses a connector to connect three hoses, each provided with irrigation holes, to a single tap. According to the present invention, there is provided an irrigation hose having two or more flow passages defined by partitions dividing the inside thereof, said irrigation hose characterised in that each of said flow passages is provided with irrigation holes formed in a member of a tube portion thereof where it is in contact with outside air; and in that said irrigation hose is made of thermoplastic resin; and in that said irrigation holes of at least one of said flow. passages differ from those in the other or each other flow passage in at least one of shape, size, formation, and pitch. When irrigating, only one of the flow passages is used at any one time. Water is conveyed through the irrigation holes of the passage to irrigate agricultural crops. If agricultural crops are cultivated on both sides of a hose, water is irrigated from the top half or from both sides of the hose. When the holes are plugged and the flow passage can be no longer used, another flow passage is used by changing the position of the irrigation hose. Thus the present invention can provide an irrigation hose with a longer life expectancy. Depending on the type of crops and their growth stages, the flow passage of the hose with the most appropriate irrigation method can be used. The present invention can also provide an irrigation hose capable of spraying water in different irrigation methods. The tube to be used for the irrigation hose may be made of stiff tube or of film. When two divided flow passages are formed in the irrigation hose of the invention, it is desirable for the flow passage used to have approximately the same sectional area as that of the inner portion of the tube so that the required flow rate of water may be achieved without changing the hydraulic pressure. In this case, the partition is made of a soft and flexible thermoplastic resin film so that the partition wall completely touches the inner tube wall of the other flow passage. The irrigation hose of the invention may pass water through a plurality of flow'passages to simultaneously irrigate different crops. This enables expansion of the irrigation area and irrigation of right and left sides with different methods simultaneously. When two flow passages are formed inside the tube and water is conveyed through both passages at the same time, there will be no problem as long as the same hydraulic pressure is applied to each passage. If the hydraulic pressure in each flow passage differs, the flow passage with the higher hydraulic pressure, designated as 1A in Figure 1, expands, and the partition, designated as 2, touches the inner tube wall, designated as 4, of the flow passage 1B with the lower hydraulic pressure, thereby blocking irrigation holes 5 of said tube wall 4 and possibly preventing the flow passage 1B from functioning. In order to solve this problem, the partition should be formed in such a way that it will not touch the inner tube wall when water is conveyed through. The irrigation holes, especially those which are required to spray water, are easily plugged. In order to reduce or prevent from plugging, it is desirable to install a filter along the flow passages, such as a sheet filter made of non-woven fabric, to at least one, and ideally to all, of the flow passages of the above mentioned irrigation hose. Brief Description of the Drawings The above and other objects, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention in conjunction with the accompanying drawings, in which: Fig. 1 is a cross-sectional view of an irrigation hose when water is conveyed through two flow passages with different irrigation methods; Fig. 2A is a perspective view showing the manufacturing process of the irrigation hose of one embodiment of the present invention; Fig. 2B is a sectional view showing the manufacturing process of the irrigation hose of the embodiment; Fig. 2C is a sectional view showing the manufacturing process of the irrigation house of the embodiment; Fig. 3 is a cross-sectional view of the irrigation hose in use, manufactured by the method shown in Fig. 2; Fig. 4 is an expanded cross-sectional view of the irrigation hose, before use, of another embodiment of the present invention; Fig. 5 shows a cross-sectional view of the irrigation hose shown in Fig. 4 in use; Fig. 6 shows a cross-sectional view of another embodiment of the present invention; Fig. 7 is a cross-sectional view of yet another embodiment of the present invention; Fig. 8 is an enlarged cross-sectional view of an irrigation hose capable of irrigating with different irrigation methods; Fig. 9 is a schematic illustration for cultivating tomatoes using the upper flow passage of the irrigation hose shown in Fig. 8; Fig. 10 is a schematic illustration for cultivating weak vegetables using the lower flow passage of the irrigation hose shown in Fig. 8; Fig. 11 is a schematic illustration of total irrigation after planting of strawberries; Fig. 12 is a schematic illustration of partial irrigation when a mulch-film is placed over strawberries bed; Fig. 13 is a cross-sectional view of an irrigation hose with two flow passages of different irrigation methods; Fig. 14 shows a cross-sectional view of the irrigation hose in use of both flow passages of the hose shown in Fig. 13; Fig. 15 is a cross-sectional view of an irrigation hose with a non-woven sheet inside the flow passage as a filter; and Fig. 16 shows a cross-sectional view of an irrigation hose with non-woven sheets in upper and lower flow passages. Detailed Description of the Preferred Embodiments Figs. 2A and 2B show two long thermoplastic resin films 12 of which widths are πr+2e and having irrigation holes 11, over one of which is a film of the same length and the width of 2r+2e, also made of thermoplastic resin, designated as 13. After placing the other film 12 over the films 13 and 12 with one long side of all three flush, the width e on the flush side is heat-sealed. Subsequently, as shown in Fig. 2C, the other side of the films 12 are laid flush with the other side of the film 13, and the other width e of the three films are heat-sealed. Thus, semicircular flow passages with the radius r, designated as 14A and 14B, are formed over and under the film 13 as shown in Fig. 3. The irrigation hose of one embodiment is structured as described above. When in use, the irrigation water is conveyed through the upper flow passage 14A as shown in Fig. 3. When plugging of the irrigation holes occurs, the irrigation hose is inverted and the flow passage 14B, now facing upward, will be used. Fig. 4 shows another embodiment of the irrigation hose, wherein a thermoplastic resin film 16 of the same length and width as the film 12 is inserted between the films 12 and both sides of the films are heat sealed. When water is conveyed through the upper flow passage 17A, as shown in Fig. 5, the film 16 will be pushed to the lower film 12, expanding 17A to form an almost circular shape. If the irrigation holes of the flow passage 17A becomes plugged, the hose is also inverted as in the case of Fig. 3. Fig. 6 shows an example of the inside of an irrigation hose 19, divided into three flow passages by such films 20 as described previously, and Fig. 7 is an example of an irrigation hose, the inside of which is divided into four flow passages. Fig. 8 shows the irrigation hose as shown in Fig. 4 wherein irrigation holes 22 are formed longitudinally at regular intervals on each side of the upper film 23, and more than three sets of regularly spaced holes are formed longitudinally regular intervals on the lower film 23. When cultivating tomatoes, as shown in Fig. 9, the irrigation hose is laid in a fashion to face the film 23 with holes on both sides facing upward, irrigating just the base of the tomatoes 24 from the holes on the sides. When cultivating weak vegetables such as napa cabbage, lettuce, and cabbage as shown in Fig. 10, the irrigation hose is laid in a fashion to make the film 23 with multiple irrigation holes formed in overall surface thereof to face upward, and spray-type irrigation is conducted overall. The descriptions above indicate an example of how the irrigation methods can be changed according to the crops being cultivated. Figs. 11 and 12 show an example of changing irrigation methods according to the growth stage of a product. Using strawberries as an example, spray-type irrigation is done when the strawberries 26 are planted (Fig. 11), and when a mulch-film 27 cover the strawberries bed, partial irrigation is done from both sides of the hose so that the irrigation holes will not be blocked by the mulch-film 27 (see Fig. 12). Fig. 13 shows the irrigation hose shown in Figs. 4 and 5, wherein irrigation holes 28 are formed throughout the upper film 12 and on both sides of the lower film 12, the width of the film 16 is narrowed and one side is heat sealed to the lower film 12, and the other side to the upper film 12, then both sides of these films are heat sealed. When overall spray-type and partial irrigation methods are simultaneously done by conveying water through flow passages 29A and 29B, the narrower film 16 will not come in contact with either upper or lower films 12 as shown in Fig. 14, even though the hydraulic pressure of the two passages are different, thereby making it possible to reliably conduct overall spray-type and partial irrigation without blocking the irrigation holes of each flow passage. Fig. 15 shows the irrigation hose as indicated in Figs. 2A, 2B, 2C and 3 wherein slit holes 31 are formed throughout the upper film 12, and round holes 32 on both sides of the lower film 12, and a non-woven sheet wider than the film 13 yet narrower than the film 12, designated as 33, is laid over the film 13, and both sides of these films are heat sealed. Fig. 16 shows an irrigation hose wherein two non-woven sheets 33 are placed over and under the film 13 and both sides of the sheets are heat sealed. The present invention, if structured as described above, is effective in the following: According to the irrigation hose of the present invention, the life expectancy of the irrigation hose can be substantially increased, as another flow passage may be used in the event that the holes of the first flow passage are plugged, and the flow passage is unable to supply water. According to the irrigation hose of the present invention, one hose is capable of different irrigation methods appropriate to different crops or growth stages without exchanging hoses or laying multiple hoses capable of different irrigation methods. The irrigation hose of the present invention, even though containing a partition, is capable of securing similar sectional area of flow passage as a hose without a partition, and therefore is capable of achieving the required flow rate of water to the required irrigation area without changing hydraulic pressure. When water is conveyed through a plurality of flow passages simultaneously, the irrigation hose of the present invention is capable of reliably conducting irrigation with different irrigation methods without the partition blocking the flow passage with uneven hydraulic pressure. According to the present invention, the irrigation hose having a filtering mechanism in flow passages, plugging in flow passages is substantially reduced or possibly prevented.

Claims: An irrigation hose having two or more flow passages (14A, 14B, 29A, 29B) defined by partitions (13,20) dividing the inside thereof; said irrigation hose characterised in that : each of said flow passages is provided with irrigation holes (11,22, 31,32) formed in a member (12, 23) of a tube portion thereof where it is in contact with outside air, and in that said irrigation hose is made of thermoplastic resin; and in that said irrigation holes (11, 22, 31, 32) of at least one of said flow passages (14A, 14B, 29A, 29B) differ from those in the other or each other flow passage (14A, 14B, 29A, 29B) in at least one of shape, size, formation, and pitch. An irrigation hose as claimed in claim 1, wherein said tube member (12,23) and/or said partitions (13,20) are made of thermoplastic resin films. An irrigation hose as claimed in any one of claims 1 or 2, wherein said irrigation hose has two flow passages (14A, 14B, 29A, 29B) defined by partitions (13,20), made of thermoplastic resin films, dividing the inside thereof, and said partitions (13,20) completely touch the tube wall of one of said flow passages (14A, 14B, 29A, 29B) when water is conveyed through the other flow passage (14A, 14B, 29A, 29B). An irrigation hose as claimed in claim 1 or 2, wherein said irrigation hose has two flow passages (14A, 14B, 29A, 29B) defined by partitions (13,20), made of thermoplastic resin, dividing the inside thereof, and the partition (13,20) does not touch the tube wall of a flow passage when water is conveyed through the other flow passage (14A, 14B, 29A, 29B). An irrigation hose as claimed in any one of claims 1 through 4, wherein a filter is installed along said flow passages (14A, 14B, 29A, 29B) in at least one of the flow passages (14A, 14B, 29A, 29B).

Inventors: HORI TOSHIHISA, OHE TATSUYA, HORI, TOSHIHISA, OHE, TATSUYA, Hori, Toshihisa, c/o Sanseki Agric. Mat., Ltd., Ohe, Tatsuya, c/o Mitsui Petrochem. Ind., Ltd.
Applicants: MITSUI CHEMICALS INC, MITSUI CHEMICALS, INC.
Application year: 1995
Main classification: B05B1
IPC codes: A01G25, B05B1