JPS6320489B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a compact, easy-to-handle, inexpensive, and strong drip-type irrigation pipe for effectively performing irrigation and fertilization in agricultural and horticultural facilities.

Drip irrigation is a method in which irrigation equipment is installed on or below the surface of the ground to reduce pressure and supply a small flow of water directly around the roots of crops over a long period of time, compared to traditional furrow methods or watering. It is a new irrigation method that is suitable for dry areas and sandy areas, and has the advantages of (1) water savings, (2) increased yields, and (3) reduced salt damage compared to conventional methods.

The main types of drip irrigation equipment mentioned above are:
Two types of irrigation nozzles are known: (1) an irrigation nozzle with a small-diameter spiral flow path provided therein, and (2) a double-walled pipe in which water flows out through small holes provided in the inner and outer walls.

These conventional irrigation devices have been devised to minimize the amount of outflow, and even when used in long lengths, the amount of outflow at the tip does not decrease significantly and can irrigate uniformly. Since it is relatively complex and requires elaborate manufacturing means, it has problems of low manufacturing efficiency and high cost.

Previously, the present inventors invented a drip-type irrigation pipe and a method for manufacturing the same to solve this problem, and filed a patent application. (Special Publication No. 57-16612). That is, it consists of a conduit part formed by peeling off the longitudinal center of the laminated surface of a strip-shaped laminated film made of at least the same or different thermoplastic resins, and a laminated joint part protruding like a fin from both longitudinal sides of this conduit part, A drip-type irrigation pipe characterized by having, at least one of the joint parts, a watering channel that branches from the conduit part and is formed by peeling the laminated part in a flow passage pattern having a constricted part, and its manufacturing method is peeling. The second method is to provide a peelable film and laminate a thermoplastic resin film thereon.

However, there are limits to thermoplastic resins that can be laminated when higher strength and durability are required as agricultural materials. Therefore, we invented a method of manufacturing drip-type irrigation pipes by heat-sealing raw material thermoplastic resins with a seal roll that can be selected from a wide range of options.

That is, in the present invention, two strip-shaped films of the same or different types of thermoplastic resin are superimposed, and the two films are thermally melted using the convex portion of a seal roll having a pattern of conduit portions and channel patterns as concave portions on the surface. A conduit part is formed in the longitudinal center of the conduit part, and laminated joint parts protruding like fins are formed on both longitudinal sides of this conduit part, and at least one of these joint parts has a conduit part that branches from the conduit part and has a constricted part. This is a method for manufacturing a drip-type irrigation pipe characterized by forming a watering channel having a channel pattern.

The present invention will be explained below using the drawings.

The irrigation pipe of the present invention is shown in Figure 1 (schematic diagram of the manufacturing process).
It is manufactured by the manufacturing process as exemplified in . First, the raw film 1, 1' is taken up by preheating rolls 2, 2', and is sandwiched between sealing rolls consisting of a heating roll 3 and a press roll 4, each having a pattern of conduit portions and channel patterns as concave portions on the surface. The convex portion of the heat roll is pressed and heat-sealed with a press roll, cooled by cooling rolls 5, 5', and taken up by take-up rolls 7, 5'.
7' and then wound up as products 8, 8'.

At this time, by forming a large number of patterns simultaneously using a wide film and slitting the spaces between adjacent patterns in the longitudinal direction with a slitter 6 before winding up the product, a large number of products can be efficiently manufactured from one production line. Can be done.

In addition, line speed (productivity) can be increased by providing a preheating roll and a cooling roll when performing heat fusing, but of course heat fusing can also be performed using a simple device that only includes seal rolls. . In either case, the advantage is that the equipment cost is significantly lower than the lamination method. There are two methods of thermal welding: a method of linearly heat-sealing the periphery of the conduit portion and the flow path, and a method of heat-sealing the entire surface other than the conduit portion and the flow path.

During heat fusing, in order to accurately create a fine channel pattern, it is necessary to feed the two films overlapping each other to avoid wrinkles.

The raw film may be a cylindrical film that is flattened and wound, or two raw films each made of one film may be used.

Therefore, the film material may be processed by the commonly used inflation method or by the T-die method.

Thermoplastic resins used in the present invention include thermoplastic resins such as polyethylene, ethylene copolymers, polypropylene, polyvinyl chloride, polyesters, polystyrene, polyamides, polyurethanes, and polymer blends thereof.

Among them, highly flexible materials such as ethylene-vinyl acetate copolymer, polyethylene, and soft polyvinyl chloride are preferred because they facilitate the outflow of water.

Furthermore, in order to produce drip-type irrigation pipes with excellent durability and heat resistance, it is preferable to use a grade with a high molecular weight and a low melt index. Polymer blends are also effective in imparting stress and crack resistance, but heat sealing is more advantageous than lamination.

Incidentally, the term "film" usually refers to anything less than 0.2 mm, but in this case, the term "film" includes anything larger than 0.2 mm. As the film, not only a film made of a single resin, but also a composite film made of a combination of different resins, a film reinforced with fibers, etc. can be used.

When using the irrigation pipe of the present invention made as described above, if water is guided to the end of the band pattern A shown in Figure 2, it will swell into a pipe shape, and the water within the conduit will further branch out from the band pattern. The flow path pattern B is invaded.

Here, the shape of channel pattern B is very important (1)
Water in the conduit enters the channel pattern at low water pressure and begins to flow out (low outflow starting pressure);
(2) The amount of outflow increases gradually with water pressure,
In order to achieve a stable flow rate, it is important to have a channel pattern with constrictions. Some embodiments of the channel pattern having constrictions according to the present invention are shown in FIGS. 3 to 13, but the present invention is not limited to these shapes.

On the other hand, examples of flow path patterns without constricted portions are shown in FIGS. 14 to 16. In the figure, a is the line width of the inlet from the band pattern A to the channel pattern B, b is the line width of the constricted portion, and c is the length of the constricted portion. Let b/a be called the aperture ratio. Appropriate range is a=3~20mm, b/a=0.7
~0.1, more preferably a=5-15mm, b/a
= 0.5 to 0.2, taking into account the required flow start pressure, required flow rate, required pressure resistance, prevention of clogging due to foreign matter contained in water, type of thermoplastic resin used, wall thickness, etc. be selected as appropriate.

The length C of the aperture part is C=0 as shown in Figures 3 to 8.
In other words, it can be tightened instantaneously, or
It may also have a long shape as shown in the figure. The aperture part is the first
As shown in Figure 3, multiple pieces may be provided in the middle of the flow path,
Further, as shown in FIG. 12, a plurality of such devices may be provided for one entrance. The constriction section is usually provided near the entrance from the band pattern A to the channel pattern B. The flow pattern in irrigation hoses is very important. The width and length of the channel determines the direction and pressure for discharging the irrigation water into atmospheric pressure.

When pressurized water is discharged into the atmosphere, especially in a drip type, it is necessary to reduce the pressure to a pressure very close to atmospheric pressure. Therefore, if there is a change in the flow path in the middle of the flow path, especially near the outlet, the flow velocity of the water in the flow path will change, and transported limescale, iron particles, etc. will be very likely to accumulate in that area. Once accumulated, the blockage grows toward the upstream part of the flow path and loses its function as a flow path.

However, near the entrance of channel pattern B, band pattern A
With sufficient pressure, it is possible to wash away the impurities that have been brought in. Therefore, it is essential to control irrigation in areas of high pressure.

The constriction part must have enough pressure to rapidly reduce the pressure from the band pattern A and at the same time to sufficiently sweep away the debris that mixes with the irrigation water downstream.

Therefore, it is desirable that the irrigation water whose pressure has been reduced by the restriction flow downstream without any change in flow velocity, with only the effect of pressure loss occurring. Therefore, it is desirable to provide the constriction portion near the entrance from the band pattern A to the channel pattern B.

When water pressure is applied to a channel pattern with a constricted part (Fig. 3) and a channel pattern without a constricted part (Fig. 14),
Fig. 17 shows an example comparing the relationship between water pressure and outflow amount. If there is no constriction part, the relationship will be as shown in A in the figure, and the water in the conduit will enter the flow path pattern, and it will be necessary to apply high water pressure for the water to start flowing out, and the amount of outflow will be It can be seen that it is difficult to control the amount of outflow due to the rapid increase in the amount of water, and that it cannot be put to practical use as an irrigation pipe. On the other hand, if a constriction part is provided, the relationship will be as shown in the figure (b), and the water will start to flow out smoothly even at low water pressure, and the outflow amount will gradually increase with the water pressure, resulting in a stable outflow amount. It can be seen that this shows that If there is no constriction part,
The inlet from band pattern A to channel pattern B is closed like a valve at low water pressure, and when high water pressure is applied, this inlet begins to open and the outflow volume increases rapidly. On the other hand, when a constriction is provided, the section from the inlet to the constriction begins to swell even at low water pressure, and this swollen state continues until the inlet valve becomes open. is observed.

It is thought that the reason why the provision of a constriction section brings about the remarkable effects mentioned above is due to the reasons mentioned above, but the idea of providing a constriction section in the flow path cannot be expected from conventional methods and devices. This is a novel idea and a method unique to the present invention.

The shape of the flow path other than the constriction part may be a simple straight pipe, but it is also possible to subtly restrict the amount of outflow, and the pressure water in the conduit can be effectively reduced, and the flow of water can be changed to a droplet shape or a gentle fountain. It is preferable to devise a shape in order to satisfy practical requirements such as being able to form a shape and being less likely to be clogged by foreign substances contained in water.
An example of such a device is shown in FIG. 2, but the invention is not limited to this in any way.

The irrigation pipe of the present invention is handled in a compact rolled form as shown in FIG. When used, the band pattern A is stretched out and laid on the surface or below the surface of the farmland in a long length as shown in FIG. 19, and then the end of the band pattern A is connected to the mouth 9 of a waterway from a water source. The end is similarly sealed by inserting a suitable stopper 10. Before flowing water, the irrigation pipe of the present invention is in a flat state, but when the valve 11 is then opened and water is introduced from the water channel, the band pattern A part becomes pipe-shaped as shown in Figure 20. A bulging conduit 12 is formed. Furthermore, water enters into the channel pattern B branched from the band pattern A, and according to the channel pattern B, water enters the inside of the laminated joint part 13 that protrudes like a fin on both longitudinal sides of the conduit part. A water sprinkling channel 14 is formed. Then, the water in the conduit section is depressurized and flows out from this water sprinkling channel 14 in a limited amount.

The outflow amount is determined by the water pressure within the conduit portion 12 and the width, length, and shape of the channel pattern B.

The spacing between the watering channels provided on both longitudinal sides of the conduit section is set appropriately depending on the purpose of use, such as the type of crop, but if the watering interval is very large, such as for fruit trees, As shown, in order not to cut the outlet of channel pattern B, a slit is made on the dotted line in the figure, and after laying the irrigation pipe during use, channel pattern B is cut only near fruit trees that require watering. It is also possible to cut the exit of

In this case, water does not flow out from channel pattern B whose outlet is not cut, making it convenient to supply water intensively and effectively only to the vicinity of fruit trees that require watering. It is. Such usage is difficult with conventional irrigation equipment, and is a new feature of the irrigation pipe of the present invention.

The irrigation pipe of the present invention, as described above, achieves the following effects.

(1) By making the channel pattern have a constricted part, the watering channel can be easily formed even at low water pressure.
The water begins to flow out, and the flow rate gradually increases along with the water pressure, making it possible to achieve a stable flow rate. The amount of outflow can be slightly restricted by the aperture ratio and length of the constriction part, and if necessary, the combination of bends, bends, or branching parts in addition to the constriction part, and even when used in long lengths, the tip The amount of water runoff does not decrease significantly, and water can be applied evenly. In addition, the pressure water in the conduit can be effectively reduced to make the water flow out in the form of droplets or a gentle fountain, and clogging caused by foreign matter contained in the water can be suppressed.

(2) Since many products can be manufactured in parallel from one manufacturing line, manufacturing efficiency is much higher than conventional methods of manufacturing irrigation equipment. Furthermore, compared to processing methods using lamination, the range of thermoplastic resins that can be used is expanded, and products with greater durability can be made.

(3) Since it becomes flat when not in use, it can be rolled up compactly. Therefore, it is very easy to install and remove, and is also convenient to transport and store. Much easier to handle than traditional irrigation equipment.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the manufacturing process of the irrigation pipe of the present invention.
Figure 2 is a plan view of the product before slitting. 3rd to 13th
The figure is a plan view showing an example of a channel pattern having a constriction part. FIGS. 14 to 16 are plan views showing examples of channel patterns without constricted portions. FIG. 17 is a diagram showing an example of comparing the relationship between water pressure and outflow amount. FIG. 18 is a schematic diagram showing the irrigation pipe of the present invention in a rolled up state. FIG. 19 is a schematic diagram showing the irrigation pipe of the present invention installed and attached to a waterway from a water source. FIG. 20 is a schematic diagram showing a state in which the irrigation pipe of the present invention is used by introducing water from a waterway. Explanation of symbols, A...band pattern, B...channel pattern,
a...Width of the entrance from band pattern A to channel pattern B,
b... Line width of the aperture part, c... Length of the aperture part, 1...
...Original film, 2...Preheat roll, 3...Heat roll, 4...Press roll, 5...Cooling roll,
6... Slitter, 7... Take-up roll, 8... Product, 9... Mouth of waterway from water source, 10... Stopper, 1
DESCRIPTION OF SYMBOLS 1... Valve, 12... Conduit part, 13... Laminated joint part, 14... Watering channel.

Claims (1)

[Claims] 1. Two thermoplastic resin strips of the same or different types are overlapped and narrowed between a heat roll and a press roll that have concave patterns of conduit portions and channel patterns as shown below on the surface, and the convex portions of the heat roll and By heat-sealing the two films with a press roll, a conduit is formed in the center of the longitudinal direction, and laminated joints protruding like fins on both longitudinal sides of the conduit are formed in at least one of the joints. It has a watering channel with a channel pattern that branches from the conduit section and has a constricted section near the inlet where the line width of the constricted section/line width of the inlet from the band pattern to the channel pattern (squeezing ratio) is 0.7 to 0.1. Method of manufacturing drip-type irrigation pipes.