CA1073944A

CA1073944A - Irrigation hose

Info

Publication number: CA1073944A
Application number: CA261,731A
Authority: CA
Inventors: Takami Sato; Toshio Mori; Susumu Kojimoto
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 1975-09-22
Filing date: 1976-09-21
Publication date: 1980-03-18
Also published as: FR2324375A1; NL7610383A; FR2324375B1; AU504944B2; DE2642158A1; AU1792376A; GB1555088A

Abstract

ABSTRACT OF THE DISCLOSURE
In an irrigation hose made of a thermoplastic resin pipe which is longitudinally partitioned by a diaphragm into a constant pressure passage and a supply passage, the constant pressure passage having small bores for water-sprinkling spaced along the length of the resin-pipe wall, and the diaphragm having small bores for communication between the passages in the longitudinal direction thereof, the improvement for assuring uniform water-sprinkling from an irrigation hose which comprises forming projections on the dia-phragm separating the passages from each other, at positions spaced along the length of the diaphragm, into the constant pressure passage to contact intimately with the resin-pipe wall of said passage, thereby forming barriers to said passage.

Description

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1 The present invention relates to an irrigation hose which is superior in appearance and strength and further assures uni*orm water-sprinkling not only on the level ground but also on the sloping ground.
Recently in the field of agriculture, irrigation, fertilization, prevention and extermination in fields and green-houses has been carried out systematically for the purpose of saving in labor and improvement in efficiency. There are two systematic methods, a sprinkler system and a drip system, both of which have advantages in certain instances. The drip system is very superior in effective use of water and ef*iciency of irrigation and further it does not change soil structure. Con-sequently, the use of the drip system is expanding more and more.
~ The term drip system refers to the one which - comprises placing a hose or a tube having holes in the longitudinal direction very close to a row of agricultural ; crops and sprinkling water therefrom. Various types of irrigation hose for this system are now used in practice.
With the hoses, however, uniform water-sprinkling along the length thereof can not be attained because the water pressure varies over a wide range depending upon the distance from the water source. Similarly, uniform water-sprinkling cannot be attained on sloping ground because the pressure is greater on the low end due to the fall of the ground.
In order to overcome these difficulties, there have been devised the following irrigation hoses which ~0 assure uniform water-sprinkling not only in the longitudinal ., ,~

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direction of the hoses but also on the sloping ground.
One is an irrigation hose made of synthetîc resin film having two parallel passages in communication with each other through holes, one passage having holes for water-sprinkling longitudinally on the outer wall and having barriers formed by melt-sticking said passage at intervals spaced along the length. Another is an irrigation hose made of cloth or rubber sheet which has the same structure as described above, the passage perforated for water-sprinkling being intercepted by seaming said passage at intervals spaced along the length. These hoses are easily produced but are poor in strength, pressure resistance, tear resistance and the like. Therefore, they are unsatisfactory as an irriga-tion hose for agricultural use. In irrigation hoses made of thermoplastic synthetic resin which are treated to improve the pressure resistance, tear resistance and durability, it is very difficult to intercept the passage by melt-sticking or seaming from the outside. Even if the passage can be intercepted, unevenness forms on the outside wall, detracting from the appearance. Further, the hose is easily broken, troublesome to handle and low in strength.
This invention provides irrigation hoses which are superior in appearance and strength and further assure uniform water-sprinkling not only on level ground but also on sloping ground.
According to the invention, there is provided in an irrigation hose having a thermoplastic resin tubular body longitudinally partitioned by a diaphragm into two passages, one being a constant pressure passage and the other being a supply passage, a plurality of small bores through the wall of the body extending from the constant pressure passage to the atmosphere for water-sprinkling, a plurality of small communicating bores through the diaphragm connecting the two passages, the improvement compris-ing a plurality of barriers in the constant pressure passage, said barriers ' 30 comprising projections, which are formed by deforming the diaphragm which ' :

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." , partitions the constant pressure passage and the supply passage, extending from said diaphragm into said constant pressure passage and being spaced along the length of the passage to contact intimately with the inside wall of the body.
The hose of the present invention will be illustrated specifically with reference to the drawings, which are only given for the purpose of illustration and not as a limitation.
Figure 1 is a longitudinal-sectional view of one embodiment of the present invention.
Figure 2 is a cross-sectional view taken on a line II-II in Figure 1.
Figure 3 is a cross-sectional view taken on a line III-III
in Figure 1.
Figure 4 is a side view of the present hose when water pressure is higher in the constant pressure passage than in the supply passage.Referring to Figure 1, reference numeral 1 is a pipe wall made of thermoplastic resin, numeral 2 is a diaphragm separating a constant pressure passage 3 and a supply passage 4 from each other, and 5 is a barrier to the constant pressure passage formed by a radial projection of the diaphragm 2 into said passage. Holes for water-sprinkling 6 are made, at intervals necessary for water-sprinkling, on the pipe wall of the constant pressure passage. Holes 7 are made in the diaphragm 2 for ; communicating the constant pressure .: :

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1 passage 3 to the supply passage 4. Water supplied to the supply passage 4 flows in the constant pressure passage

3 through the holes 7 made in the diaphragm 2 and is kept at a constant pressure. The water is then sprinkled through the holes 6 in the pipe wall of the passage 3, The diameter of the water-sprinkling holes is preferably 0.3 to 1 mm. A ratio of the distance between the water-sprinkling holes 6 to the distance between the communicating-holes 7 may optionally be selected, however, it is desirable that the latter distance is 2 to 8 times as long as the former distance. The diameter of communicating holes is preferably 0.3 to 1 mm. Both holes sizes may be varied along the length of the hose and the determined amount of the sprinkled water. The diameter of the present hose is more than 13 mm and preferably 15 to 50 mm. The barrier 5 is effective independently of the length of the portion contacting with the pipe wall, however a length of less than 5 cm is preferred.
- When the hose of the present invention is used .; 20 on level ground, good uniformity of water-sprinkling is assured, irrespective of the distance between the barriers 5 formed in the constant pressure passage 3 by projections from the diaphragm 2 separating the passages 3 and 4 from each other. On the other hand, when the hose of the present invention is used on sloping ground, the distance between the barriers 5 is very important for obtaining uniform water-sprinkling. In this case, it is desirable to determine the distance so as to correspond to less than a 20 cm head, preferably a 5 to 10 cm head of water on sloping ground. For example, when a hose of , 1 50 m in length is used on sloping ground with a 1 m ; head of water, it is sufficient to form five barriers at a definite distance of less than 10 m.
In Figure 1, when side A is higher in level than side B, water flows in the supply passage 4 from a water source (not indicated in the drawing) and passes through the communicating holes 7 into the constant pressure passage 3 wherein the water is kept at a definite pressure. The water is then uniformly sprinkled through the holes 6. Because the water pressure applied to the supply passage 4 is relatively high, it is hardly affected by the water head between sides A and ~. Further, in the constant pressure passage 3, the water head between sides A and B is equally divided by the barriers 5 formed in the passage 3 to such a degree that the amount of water sprinkled through the holes 6 is substantially uniform. Accordingly, the amounts of water sprinkled through the holes 6 become uniform even when the hose -~
is used on sloping ground.
In the irrigation hose of the present invention, the diaphragm in the hose is projected into one passage to contact intimately with or alternatively to melt-stick to the wall of the hose. Consequently, unevenness does not form on the outside wall of the hose and the appearance of the hose is not damaged. Further, the hose does not easily break nor bend, is easy to handle, is not damaged by bending and further is superior in - strength.
The irrigation hose of the present invention shows desirable characteristics other than those mentioned 1~)'73~4~

1 above. In general, water for agricultural use is supplied from rivers, ponds, wells and the like. Since water from these sources contains a large amount of suspended matter such as dusts or algae, it blocks the hose with this matter when supplied to the hose directly and repeatedly. Thus water-sprinkling becomes non-uniform and finally becomes impossible due to complete blockage.
In order to prevent blockage of the hose con-sideration has been given to setting up a high-performance filter capable of collecting the smallest suspended matters or to treat the water with chemicals. The former is very expensive and requires a complicated operation and the latter is not desirable in terms of adverse affects ` on crops and safety in handling. Further, opening the blocked holes with a thin wire may also be considered but it requires much labor and much time.
In the hose of the present invention, the ; barriers 5 intercept the constant pressure passage 3 when water pressure is higher in the supply passage than in said passage 3. While, when water pressures in both passages are reversed, the barriers turn over and project into the supply passage to open the constant pressure passage. In this way, washing the hose becomes easy and the problems described above can be solved.
Figure 4 is a side view of the present hose when being washed. The hose maintains the configuration shown in Figure 1 while being used in a usual way, but it takes the shape as shown in Figure 4 while being washed. When the hose is used under usual conditions, water pressure is higher in the supply passage than in 10'73~44 1 the constant pressure passage, and the barriers 5 formed by deformation of the diaphragm 2 separating the two passages from each other project toward the pipe wall of the constant pressure passage and contact intimately therewith. Consequently, uniform water-sprinkling becomes possible even on sloping ground. When the water-sprinkling holes 6 and the communicating holes 7 are blocked with suspended matters such as dusts and algae, or microorganisms, high-pressure water or air is supplied to the constant pressure passage 3. Then, the barriers 5 in said passage 3 turn over by the applied pressure and project into the supply passage, as shown - in Figure 4. Thus, a high pressure is applied be-tween both ends o~ the passage 3, and the high-pressure water or air gushes out through the water-sprinkling holes 6 and the communicating holes 7. In this way, the hose can be washed with ease.
Eor the material for the irrigation hose of the present invention, any thermoplastic resin may be ~ 20 usable and among them polyolefin resins and polyvinyl ; chloride resins are particularly preferred.
A preferred embodiment of the present invention will be illustrated hereinafter.

Twenty irrigation hoses of the present invention of 50 m each in length were placed in parallel on the sloping field (50 m in length, 20 m in width, a slope of l m in 50 m). The hoses had water-sprinkling bores (0.5 mm in diameter) at intervals of 20 cm, communicating ~ f ll)~ 3~ L'~ ~

bores (0.4 mm in diameter) at intervals of 80 cm and barriers to the constant pressure passage at intervals of 5 m. Water was supplied to the supply passage under a pressure of 0.5 kg/cm2 and a very good uniformity of water-sprinkling was obtained as follows: the amount of sprinkled water was 19 cc/min/hole at the entrance of the hoses (at high level) and 20 cc/min/hole at the exit of the hose (at low level). After the hoses were used for about one month, it was found that about 50%
of the bores for water-sprinkling were blocked. However, the blockage was completely eliminated by washing with water supplied to the constant pressure passage under a pressure of 1 kg/cm . The hoses thus washed showed the same uniformity of water-sprinkling as that at the initial stage.
The hose of the present invention is easily - produced according to the method developed by the inventors as disclosed in co-pending Canadian Application No.
261,725). That is, in the method for the production of special resin pipes which comprises integrally extruding the pipe and the diaphragm, or separately extruding them both and melt-sticking them together into a pipe having a diaphragm therein, and applying a force, from the inside of one passage~ to the freshly extruded diaphragm at a right angle thereto at proper spacing longitudinally, whereby the diaphragm is deformed and projected into the ; other passage tG contact intimately with or alternatively . .

.~, ,, ~ - 8 -lt~ 44 1 to melt-stick to the pipe wall of said passage thereby forming barriers to said passage. The hose of the present in~ention is produced by making small bores in the diaphragm of the pipe thus obtained for com-municating the passages, and small bores for water-sprinkling, longitudinally and at spaced intervals as necessary for sprinkling, in the pipe wall of the intercepted passage.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In an irrigation hose having a thermoplastic resin tubular body longitudinally partitioned by a diaphragm into two passages, one being a constant pressure passage and the other being a supply passage, a plurality of small bores through the wall of the body extending from the constant pressure passage to the atmosphere for water-sprinkling, a plurality of small communicating bores through the diaphragm connecting the two passages, the improvement comprising a plurality of barriers in the constant pressure passage, said barriers comprising projections, which are formed by deforming the diaphragm which partitions the constant pressure passage and the supply passage, extending from said diaphragm into said constant pressure passage and being spaced along the length of the passage to contact intimately with the inside wall of the body.

2. An irrigation hose according to claim 1, wherein said barriers in the constant pressure passage are positioned closely to the pipe wall of the passage.

3. An irrigation hose according to claim 1, wherein said barriers are formed so as to intercept the constant pressure passage when water pressure is higher in the supply passage than in the constant pressure passage and to flex so as to open said passage when the water pressures in the passages are reversed.

4. An irrigation hose according to claim 1, wherein the space between said communicating small bores is 2 to 8 times as long as that between small bores for water-sprinkling.

5. A method for the production of an irrigation hose according to claim 1 comprising the steps of extruding a tubular body and a diaphragm which divide the body into two passages; deforming and projecting the diaphragm into one passage to contact intimately with the body wall of said passage thereby interrupting said passage; said deforming being accomplished by applying a force, from the inside of the other passage, to a freshly extruded diaphragm at a right angle thereto at longitudinally spaced inter-vals, while integrally extruding the body and the diaphragm or separately extruding them both and melt-sticking them together in a body having a diaphragm therein and then forming small bores in the diaphragm for communicating the passages and small bores in the body wall for water-sprinkling.

6. A method for the production of an irrigation hose according to claim 1 comprising extruding the hose and extruding said diaphragm into the hose while deforming the diaphragm radially outwardly at spaced intervals along its length to form barriers extending into one passage and toward the inside wall of the hose, forming a plurality of openings in the diaphragm to interconnect the two passages and forming a plurality of openings in the wall of the hose to interconnect the constant pressure passage and the atmosphere.