Method and system for manufacturing an irrigation pipe

Abstract

A piece insertion method for a pipe, for example an irrigation pipe, including: ejecting at least one piece, for example a dripper, from an ejection unit, advancing the at least one dripper inside the irrigation pipe by a dripper advancing unit, lifting the dripper towards the inner surface of the irrigation pipe by using a lifting device such that the dripper is parallel or substantially parallel to this inner surface of the irrigation pipe on impact with this inner surface. The method according to the invention allows also coordination between the lifting device, the ejection unit and the dripper advancing unit such that the dripper spacing can be maintained in tight tolerances.

Claims

1. A piece insertion method for a pipe; comprising the steps of: providing a pipe and providing at least one piece to be inserted into said pipe; ejecting said piece from an ejection unit, advancing said piece inside said by a piece advancing unit, placing said piece on a lifting device which moves according to an up and down lifting motion and wherein said lifting device is actuated by at least one of the group consisting of an electro-mechanical actuator, an electromagnetic actuator, a magnetostrictive actuator, and an electrical actuator, catapulting said piece inside the pipe towards an upper inner surface of said pipe using said up lifting motion of said lifting device, such that said piece enters for the first time in contact with said upper inner surface of said pipe, in order to weld said piece against said inner surface, with said piece being parallel or substantially parallel to said inner surface of said pipe on impact with said inner surface.

2. The piece insertion method of claim 1, said piece comprising at least a layer or surface which enters in contact with the upper inner surface of the pipe and which is made by a material suitable to be hot-welded to the pipe.

3. The piece insertion method of claim 1, said piece being a dripper.

4. The piece insertion method of claim 1, comprising: detecting said piece using a detector, generating a first electrical signal using said detector when the detector has detected said piece, triggering the lifting of said lifting device based on said first electrical signal.

5. The piece insertion method of claim 4, comprising: using said first electrical signal for coordinating the lifting of said lifting device with the advance of said piece.

6. The piece insertion method of claim 5, comprising using said first electrical signal for calculating an advancing rate of said piece advancing unit.

7. The piece insertion method of claim 1, comprising: using a stop end to stop the piece before it is lifted.

8. The piece insertion method of claim 1, comprising: generating a second electrical signal using said lifting device, using said second electrical signal for calculating an advancing rate of said piece advancing unit.

9. The piece insertion method of claim 1, comprising: welding said piece to said inner surface of said pipe by using the pressure exerted by the lifting device and the heat of the pipe.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be better understood with the aid of the description of an embodiment given by way of example and illustrated by the figures, in which:

(2) FIG. 1 shows a known dripper insertion device.

(3) FIG. 2 shows another known dripper insertion device.

(4) FIG. 3 shows some drawbacks related to the dripper insertion device of FIG. 2.

(5) FIG. 4 shows one embodiment of the dripper insertion device according to the invention.

(6) FIGS. 5A to 5C show three views of an embodiment of the lifting device according to the invention.

DETAILED DESCRIPTION OF POSSIBLE EMBODIMENTS OF THE INVENTION

(7) FIG. 4 shows one embodiment of the piece insertion device for an extruded pipe 2 according to the invention. The extruded pipe 2 is suitable for containing a fluid, i.e. liquid or a gas. The extruded pipe 2 can be suitable also for containing a solid material.

(8) As discussed the piece 1 comprises at least a layer or surface which enters in contact with the inner surface of the pipe and which is made by a material suitable to be hot-welded to the pipe, by exploiting the heat of the pipe. For example each piece 1 can comprise a polymeric surface or an adhesive or lacquer layer to enable the sticking effect by using the heat of the pipe. In a preferred embodiment the inserted piece is a dripper.

(9) In the illustrated embodiment the extruded pipe 2 is an irrigation pipe suitable for containing a liquid, for example some water, and the piece 1 is a dripper.

(10) In the embodiment of FIG. 4 the device according to the invention comprises: an ejection unit not illustrated for ejecting at least one dripper 1, a dripper advancing unit not illustrated for advancing the dripper 1 inside the irrigation pipe 2, a lifting device 10 which advantageously lifts each dripper 1 towards the inner surface of the irrigation pipe 2 such that the dripper 1 is parallel to the inner surface on impact with this inner surface.

(11) The ejection unit can comprise orienting means for feeding the drippers to the irrigation pipe along a determined orientation.

(12) The dripper advancing unit can be of different types: known devices include moving belts that impart a constant velocity on the drippers, mechanical devices that advance the drippers in discrete stop-and-go strokes, pneumatic systems where drippers are pushed forward by an air flow, etc. Other systems may be used as well. In one embodiment the speed of the drawn pipe is higher than the advancing speed of the drippers. In a preferred embodiment the pipe's speed is at least 10 times higher than the drippers' speed.

(13) In one embodiment drippers 1 are fed from a reservoir to a vibrating bowl feeder which aligns the drippers having the flow path surface as the upper surface. The so aligned drippers 1 are feed individually to a moving belt. A dripper buffer can be provided between the vibrating bowl feeder and the moving belt. The moving belt moves the drippers 1 towards the dripper advancing unit that advances dripper on the insertion stick, which extends to the inside of the calibrator unit.

(14) The dripper advancing unit is placed between the moving belt (or in general the ejection unit) and the calibrating unit in order to regulate the advancing speed of the drippers 1 so as to feed them inside the calibrator on the insertion stick with the desired speed. This dripper advancing unit can comprise two arms which pick up and drop off alternatively the drippers 1 and the acts also as regulating unit.

(15) In the described embodiment the ejection unit comprises all the elements before the insertion stick, in particular the reservoir, the vibrating bowl feeder as orienting means, the buffer and the moving belt.

(16) In other embodiment the ejection unit and the dripper advancing unit can be the same unit.

(17) The lifting device 10 allows a damage-free insertion. Since the dripper 1 is maintained parallel to the inner surface of the irrigation pipe during the lifting and on impact with this inner surface, the risks of impact deformation of the irrigation pipe 2 are eliminated or at least greatly reduced.

(18) In the embodiment of FIG. 4 the insertion stick 20 is fixed and the dripper advancing unit comprises pneumatic systems where the dripper 1 is pushed forward by an air flow. The insertion stick 20 is equipped by the lifting device 10.

(19) As discussed, the lifting device 10 can be actuated by a mechanical, electro-mechanical, purely electric or any other kind of actuator that brings the dripper into contact with the pipe.

(20) The lifting mechanism can be based for example and in a non limitative way on electromagnetic coils, on a piezoelectric device, on a mechanical or pneumatic or electro-pneumatic device, etc.

(21) In a preferred embodiment the lifting device is actuated by one or more voice coil actuators 100, illustrated in FIGS. 5A and 5C, similar to those attached to the apex of a loudspeaker cone. Each voice coil 100 is wound around a core made by two layers, the lower layer comprising a permanent magnet 102 and the upper layer a metal 104.

(22) By driving a current through the voice coil 100, a magnetic field is produced. The voice coil 100 reacts to the magnetic field from the fixed permanent magnet 102, thereby causing the moving upwardly and downwardly of the voice coil 100 itself along with the two bending or spring elements 112 which support the dripper 1 through the support element 108. The support element 108 can comprise an insulating material. It has to be suitable for supporting the heat from the pipe and/or from the voice coil. For example it is made of a high quality polymer or of ceramic.

(23) The two elements 112, which are fixed to the insertion stick 20 by the screws 110, act as two springboards causing the lifting of the support element 108 and then of the dripper 1. Another layer of any metal 106, different from iron or any other ferromagnetic metal, is placed between the elements 112 and the layer 104.

(24) As illustrated in FIG. 5C a dripper 1 can then be lifted by the voice coil 100. In the embodiments illustrated on FIGS. 5A and 5B there are two voice coils 110 which allow a fine adjustment of the dripper tilt, such that the dripper 1 is always parallel to the inner surface of the irrigation pipe 2 on impact. However other embodiments comprising only one voice coil, which is easier to control, or more than two voice coils are possible.

(25) In a preferred embodiment the voice coils 100 are placed on the end of the insertion stick after the calibrator.

(26) In another embodiment the same cooling liquid, e.g. the cooling water, used for avoiding the dripper to glue on their supports, is used for cooling the voice coils too.

(27) In one embodiment some elastic energy can be stored in the lifting device before that a piece 1 is placed on it. For example a negative signal can supply the voice coils 100 in order to cause a downward bending of the springs 112. In other words the springs 112 are pre-loaded. In such a case the piece 1 will be lifted with a bigger power.

(28) In a preferred embodiment the signal supplying each voice coil 100 is periodic square signal with a frequency of about 33 Hz. It is of course possible to vary the amplitude and the temporal length or frequency of each impulse for modifying the lifting of the lifting device.

(29) In another embodiment a negative signal whose amplitude is smaller than the amplitude of the positive impulse can supply the voice coils between two consecutive impulses in order to avoiding undesired oscillations of the system.

(30) In one embodiment the length of the lifting device is smaller than the length of the dripper 1. In a preferred embodiment the lifting device is placed under the dripper 1 such that the center of mass of the dripper is above the lifting device. In a preferred embodiment the middle of the lifting device and of the dripper 1 coincide. In other words the dripper 1 is placed symmetrically on the lifting device. For example the dripper is 30 mm long, the lifting device is 20 mm long and 5 mm at the rear end of the dripper 1 and 5 mm at its front end are not in contact with the lifting device. In such a case the length of the rear section of the dripper which is not in contact with the lifting device is calculated so as to allow the advance of the next dripper during the lifting of the previous one.

(31) According to another embodiment the length of the dripper 1 is smaller than the length of the lifting device. According to another embodiment the dripper 1 is not placed symmetrically on the lifting device: its center of course nevertheless is above the lifting device.

(32) According to another embodiment a ramp, similar to the ramp 22 of FIG. 2 is in any case present for allowing the insertion of the drippers 1 if the lifting device does not work or in case of lack of synchronism.

(33) The lifting motion of the lifting device 10 and the dripper motion on the insertion stick need to be coordinated. In one embodiment this coordination is based on the detection of the passage of a dripper 1 by a detector 30. This detector 30 generates a first electrical signal which triggers the lifting of the lifting device 10, which then moves from a first position 10 to a second position 10.

(34) In this embodiment this first electrical signal can be advantageously used for coordinating the lifting with the advancing of the drippers 1. In particular the first electrical signal can be used for calculating the dripper advancing rate.

(35) If the dripper advancing unit comprises moving belts that impart a constant velocity on the drippers 1 or mechanical devices that advance the drippers in discrete stop-and-go strokes, this first electrical signal can be advantageously used for coordinating the lifting with the advancing speed of these devices.

(36) If the dripper advancing unit comprises pneumatic systems where the dripper is pushed forward by an air flow, this first electrical signal can be advantageously used for calculating the power of this air flow.

(37) In another embodiment the lifting device 10 itself generates a second electrical signal which can be used for calculating the dripper advancing rate. This latter approach allows for intrinsically better precision of the dripper spacing and does not require the use of an additional device as the detector 30.

(38) In another embodiment the dripper advancing unit generates a third electrical signal which can be used for calculation of the lifting rate of the lifting device.

(39) As discussed the first, second and third signal can be evaluated separately, double or together by an electronic module for the mentioned coordination between the lifting and the advancing of the drippers.

(40) The electronic module can belong to the lifting device 10 and/or to the ejection unit and/or to the advancing unit. In another embodiment the electronic module belongs to a device different from the lifting device, the ejection unit and the advancing unit, but connected to them by any kind of wireless or wired connection.

(41) The lifting device 10, the ejection unit and the advancing unit communicate electronic signals by any kind of wireless or wired connection.

(42) In FIG. 4 the insertion stick 20 comprises an end stop 24 which is caused by an abrupt change of thickness of the insertion stick 20 from h.sub.1 to h.sub.2>h.sub.1. The height h.sub.2h.sub.1 of this end stop 24 is at least equal or superior to a fraction of height of each dripper 1, in order to stop it and to define then a fixed location for its lifting.

(43) The lifting device in the embodiment of FIG. 4 is placed in a fixed position under the stopped dripper 1. In such a case the dripper detector 30 is not necessary and the coordination between the lifting device 10 and the dripper motion on the insertion stick is performed for example by using the mentioned second electrical signal, generated by the lifting device 10.

(44) After the lifting device 10, the thickness of the insertion stick 20 is maintained higher, equal to h.sub.2, so as to form a support surface for the pinching wheel 50 or in general for a perforating unit.

(45) In one embodiment the lifting device 10 can simply catapult the dripper 1 in contact with the inner surface of the irrigation pipe 2. The pressing of each dripper 1 with a certain force against the inner surface of the irrigation pipe 2 will be performed by using a surface belonging for example to the pinching wheel 50.

(46) In another embodiment the lifting device 10 can exert some pressing force as well.

(47) The parallelism on impact between contacting surfaces of the dripper 1 and of the irrigation pipe 2 ensures an even and uniform welding of the dripper 1 to the irrigation pipe 2.

(48) In the described embodiments the lifting of the piece 1, for example a dripper, is performed inside the pipe 2. However it is possible also to lift the piece 1 such that it enters into contact with the outer surface of the pipe 2. In this case the lifting device is placed outside the pipe 2. The lifting device in such a case can be used for placing on the outer surface of the pipe a mark or a sign for localizing the drippers 1.

(49) The lifting of the piece 1 can be performed before the calibrator unit or inside the calibrator unit or after the calibrator unit.

(50) The pieces 1 can be advanced in constant movement or in sequenced motion (stop and go).

(51) A piece can be a sensor, for example for measuring the flow rate of the liquid inside the pipe. In another embodiment it can be a temperature sensor, a pressure sensor or any other kind of sensor.

(52) According to another embodiment the piece 1 is a transponder comprising means for emitting and/or receiving signals. In an example, after inserting the transponder 1 inside the pipe 2, a hole can be drilled on the pipe 2 in correspondence of the piece 1, for example for connecting the transponder to an external device comprising an antenna by using some wires.

(53) According to another embodiment the piece 1 is an element for reinforcing any kind of extruded pipe 2 before its drilling and/or for assuring its waterproofness and/or airproofness in correspondence of the drilled holes. For example the piece 1 can be a nut cooperating with an external screw. The piece 1 can be in general any piece which can cooperate mechanically and/or electrically with an external piece or device.

(54) According to another embodiment the lifted piece 1 is a stapler hot-welded to the inner surface of the pipe. In such case the elements which have to be fixed to the inner surface of the pipe 2, for example and in a non limitative way drippers and/or LEDs and/or sensors, can be connected by one or more wires as a string of pearls, the pearls being the mentioned elements. The wires can be electric or optical wires. The string can be advanced in constant movement or in sequenced motion (stop and go) over the thermal stapler. The thermal stapler comprises one or more groove, each groove having a form suitable for containing one or more wires.

(55) As discussed the string is advanced over the staplers. When the wire(s) of the string are over the thermal stapler, it can then be lifted so as to thermally fix it and the wire(s) to the inner surface of the pipe. In other words the stapler acts on the element string such as the clips or fasteners fixing an electric wire on the wall of a house.

(56) The two last embodiments can be combined: in this case the pipe can be drilled in correspondence of the wires and an external device can enter into contact with the wires for example for transmitting and/or receiving a signal. In another embodiment an external device marks the pipe in correspondence of a piece 1 inside the pipe.

(57) According to another embodiment the piece 1 is a polymeric piece comprising a magnetic tape recording some information, for example information about the manufacturing of the pipe 2 or used for tracking purpose. The piece 1 can also comprise a RFID tag, a chip, a memory or any other integrated circuit allowing it to store data.

(58) According to another embodiment the piece 1 is a pastille or lozenge having a controllable solubility. Herbicides, weedkillers, nutrients vitamins or additives can then be dissolved in the fluid contained in the pipe.

(59) According to another embodiment the piece 1 is a gas dripper, i.e. a dripper which allows some gas in the pipe 2 to come out from the pipe 2 in order to clean up some water or liquid in general, for example the water of the sea, of a river, of a lake, of a dam, of a swimming pool, etc.

REFERENCE NUMBERS USED ON THE FIGURES

(60) 1 Piece, for example a dripper or drip element 2 Pipe, for example an irrigation pipe or hose 10 Lifting device 10 Lifting device in a first position 10 Lifting device in a second position 20 Conveying unit or insertion stick 22 Ramp of the insertion stick 24 End stop of the insertion stick 30 Detector of drippers 40 Calibrator 50 Perforating unit or pinching wheel 100 Voice coil 102 Fixed permanent magnet 104 Metal layer 106 Metal layer different from iron 108 Support element 109 Linking element 110 Screw 112 Bending element a Angle H Horizontal line