Device and method for processing pipe fittings made of thermoplastic material

Abstract

The invention relates to a device for processing a pipe (20) made of a thermoplastic material; each tube (20) extends along a longitudinal axis (A) and has a first end (22) and a second end (23); the device (1) comprises an element (4) for chamfering a portion (24) of a first end (22) of a pipe (20), the element comprising at least one machining tool (5) having a respective machining surface (6); a heating device (7) associated with the machining tool (5) is configured for heating a machining surface (6) of the machining tool (5) to a predetermined temperature.

Description

Technical Field

[0001] The present invention relates to a device and a method for processing a pipe made of thermoplastic material, in particular to a device and a method for performing specific processing on the end of the pipe.

[0002] Thermoplastic pipe is usually produced in a facility by an extrusion process that discharges the material in a plastic state using a rotating screw system that forces the material through a calibrated die of the appropriate shape and size. A pipe production facility is called an extrusion line and it includes several pieces of equipment, each designed for a specific function.

[0003] In this facility, there is usually a machine, which is generally located at the end of the production line, called a cutter and is configured to divide the extruded continuous tube into pieces of prescribed and predetermined lengths. More specifically, the machine comprises a cutting unit mounted on a movable carriage that can move synchronously with the extruded tube as required and is equipped with clamping devices configured to couple with the tube during the cutting operation.

[0004] Pipe sections made of thermoplastic material produced in this way are generally used to form rigid pipes for sanitary purposes inside buildings, for outdoor rainwater, and for water distribution and drainage.

[0005] In general, in order to create a pipe with a specified total length, the segments require, in addition to cutting, that one of the ends of the segment be tapered.

[0006] This operation is called chamfering, and its purpose is to facilitate the connection with the opposite end of an equivalent pipe, on which a specific flared widening portion, called a bell, is formed to create a continuous channel for conveying fluids. This chamfering operation can be carried out simultaneously with the cutting operation or after the cutting operation.

[0007] For the above-mentioned types of pipe fittings, cutting and chamfering are usually carried out by removing material.

[0008] A typical thermoplastic material for manufacturing the above-mentioned pipes is, for example, PVC-U, a material having a brittle mechanical behavior but a particularly high hardness.

[0009] In order to effectively chamfer the ends of pipes, cutting machines are usually equipped with a motor-driven tool that is equipped with an edge cutter or a surface coating of an abrasive material.

[0010] Therefore, chamfering operations, by removing material, generate chips and dust, and create a series of problems, including rapid wear of machining tools and mechanical parts of the machine, the need for suitable systems to extract and capture the generated dust, and finally the need to collect, store and dispose of all waste products generated by cutting and chamfering operations.

[0011] In view of all the above, it is becoming increasingly important to have a method and an apparatus capable of machining (mainly chamfering) tubes without removing material, ie without generating chips and / or dust. Background Art

[0012] Devices are known in the technical literature that make it possible to chamfer a tube made of thermoplastic material without removing material by using a heating unit which, before the chamfering operation, locally changes the rheological state of the material to a temperature that makes it easy to deform.

[0013] Machining without material removal results in slower machining times than machining with chip removal, but nevertheless has undoubted advantages by solving the various problems mentioned above. Summary of the invention

[0014] The object of the invention is to chamfer the ends of a pipe and to increase the production speed relative to the solutions of the prior art.

[0015] Against this technical background, the Applicant has prepared an apparatus and a method for processing a pipe made of thermoplastic material, comprising the technical features described in the respective independent claims.

[0016] Advantageously, the device and the related method allow chamfering of tubes made of thermoplastic material without removing material, thus guaranteeing excellent productivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Advantageously, the device and the related method allow chamfering of tubes made of thermoplastic material without removing material, thus guaranteeing excellent productivity.

[0018] With reference to the above objects, the technical features of the present invention are clearly described in the following claims, and the advantages of the present invention will be more apparent from the following detailed description with reference to the accompanying drawings showing preferred, non-limiting exemplary embodiments of the present invention, in which:

[0019] - Figure 1 is a schematic side view of a machine capable of cutting pipe sections of predetermined length, starting from a pipe, for example made of continuously extruded thermoplastic material, and on which the device according to the invention can be mounted;

[0020] - Figure 2is a schematic perspective view of a detail of an apparatus according to the invention;

[0021] - Figure 3 is a schematic perspective view of further details of the apparatus according to the invention;

[0022] - Figure 4 yes Figure 3 A schematic elevation view of a detail of;

[0023] - Figure 5A , 5B and 5C schematically show the Figure 2 The sequence of steps for machining a pipe fitting with the details shown in ;

[0024] - Fig. 6A , 6B 6C each show a schematic block diagram of a machine according to the present invention according to a respective embodiment. DETAILED DESCRIPTION

[0025] With reference to the figures, numeral 1 denotes an apparatus for processing a pipe 20 made of thermoplastic material, in particular a pipe 20 made of PVC-U, for example.

[0026] Pipes made of thermoplastic materials such as PVC-U are taken as an example, since they are the pipe sections that usually require such processing and are used to make pipelines for conveying and discharging fluids of this type, but this obviously should not be seen as limiting.

[0027] According to the embodiment shown, the apparatus 1 is preceded by a station 2 for feeding a continuously extruded tube 21 having a longitudinal axis A parallel to the direction of advancement, these tubes 21 being subsequently divided into individual tubes 20, as explained in more detail below. Alternatively, the feeding station 2 feeds the apparatus 1 with a series of individual tubes which are designed to be divided into tubes 20 of shorter lengths.

[0028] The cutting unit 3 divides the continuously extruded tube 21 into a plurality of tubes 20 or, according to an alternative embodiment, divides a supplied individual tube into tubes 20 of shorter length.

[0029] Each tube 20 has a first end 22 and a second end 23 and a main longitudinal extension axis A.

[0030] According to an aspect of the invention, the cutting unit 3 comprises at least one cutting tool 16 .

[0031] The device 1 comprises a chamfering station 14 equipped with a chamfering element 4 designed to carry out a chamfering operation.

[0032] In particular, the device 1 comprises an element 4 for chamfering a portion 24 of a first end 22 of a respective pipe 20 .

[0033] More specifically, the term "chamfering of the end" refers to forming a tapered portion at the end of a pipe, which facilitates connection, for example, to the end of an equivalent pipe after a specific widening process at the rear end, namely the so-called flaring.

[0034] The chamfering element 4 comprises at least one machining tool 5 having a machining surface 6 .

[0035] According to a preferred embodiment, the chamfering element 4 comprises a contact element 9 .

[0036] The contact element 9 is designed for cooperating with the machining tool 5 .

[0037] The machining tool 5 and the contact element 9 are configured to pass between an inoperative position P1 , in which they are not engaged with the pipe 20 , and an operative position P2 , in which they are in contact with respective surfaces 26 , 27 of the portion 24 of the first end 22 of the pipe 20 .

[0038] In the inoperative position P1 , the machining tool 5 and the contact element 9 are not in contact with the pipe 20 .

[0039] More specifically, the contact element 9 actively participates in the chamfering together with the machining tool 5 in such a way as to support the portion of the tube to be chamfered in order to prevent collapse.

[0040] In the operating position P2 , the machining tool 5 is in contact with the outer surface 26 of the portion 24 of the first end 22 of the tube 20 , and the contact element 9 is in contact with the inner surface 27 of the portion 24 of the first end 22 of the tube 20 .

[0041] Specifically, in the operating position P2 , the machining surface 6 of the machining tool 5 is in contact with the outer surface 26 of the portion 24 of the first end portion 22 of the pipe 20 .

[0042] It should be noted that, in order to carry out the chamfering, each tube 20 cut by the cutting unit 3 must be moved appropriately away from the tube already obtained.

[0043] For example, according to an embodiment in which the tube 20 is obtained by cutting the continuously extruded tube 21 , a specific device not shown in the drawings is configured for moving the tube 20 away from the continuously extruded tube 21 .

[0044] According to an embodiment, the device 1 comprises an element 10 for supporting the chamfered element 4 .

[0045] The support unit 10 comprises a movement device 11 which is configured for radially moving the machining tool 5 relative to the pipe 20 from the inoperative position P1 to the operative position P2 and vice versa.

[0046] For example, the movement device 11 comprises an actuator, for example of the hydraulic, pneumatic or electric type, and an articulation system connected to the machining tool 5 .

[0047] According to an embodiment, further movement means 28 , for example of a hydraulic, pneumatic or electric nature, are configured for moving the contact element 9 between the inoperative position and the operative position.

[0048] In other words, in the operating position P2 , the machining tool 5 is forced toward the outer surface of the portion 24 of the first end 22 of the tube 20 , while the contact element 9 is in tangential contact with the inner surface of the same portion 24 of the first end 22 .

[0049] According to an aspect of the invention, the support element 10 is configured to rotate the chamfering element 4 about the axis A of the tube 20 , in particular for producing at least one complete rotation of the chamfering element 4 about the axis A of the tube 20 .

[0050] Advantageously, by means of such a rotation or a series of rotations of the supporting element 10 , the chamfering element 4 is able to chamfer the tube 20 over the entire circumference of the portion 24 of the first end 22 of the tube 20 .

[0051] According to the invention, the apparatus 1 comprises a heating device 7 associated with the machining tool 5 and configured for heating the machining surface 6 of the machining tool 5 to a predetermined temperature.

[0052] Advantageously, the machining surface 6 heated by the heating device 7 allows direct heating of the end portion of the tube 20 being chamfered during the chamfering operation, in particular when the machining tool 5 is in the operating position P2 .

[0053] Advantageously, directly heating the end portion of the tube 20 to be chamfered during the chamfering operation allows chamfering to be performed by plastic deformation of the tube 20 , thus without removing material, ie without forming chips and dust.

[0054] In fact, the tube 20 made of thermoplastic material changes its relative rheological state, at least locally, at a temperature greater than or equal to a predetermined threshold (depending on the nature of the material itself), becoming plastic and therefore deformable.

[0055] Advantageously, directly heating the end portion of the tube 20 to be chamfered during the chamfering operation makes it possible to speed up the chamfering operation compared to the prior art.

[0056] Thus, accelerating the chamfering operation increases the productivity of the apparatus 1 .

[0057] According to a preferred embodiment, the heating device 7 is in contact with at least part of the processing tool 5 .

[0058] Preferably, the machining tool 5 has the shape of a truncated cone with a larger base designed to come into contact with the heating device 7 .

[0059] According to other embodiments that are not shown, the machining tool 5 can be, for example, cylindrical and its axis of rotation suitably inclined relative to the axis of the pipe 20 .

[0060] The frustoconical shape of the heated machining tool 5 allows the portion 24 of the first end 22 of the tube 20 to be tapered, thereby plastically deforming the machining tool 5 when it is in the operating position P2.

[0061] According to an aspect of the present invention, the machining tool 5 is configured to rotate about a respective rotation axis A1 .

[0062] Advantageously, when the machining tool 5 is in the operating position P2 , the rotation of the machining tool 5 facilitates the chamfering of the portion 24 .

[0063] According to a preferred embodiment, the machined surface 6 of the tube 20 is free of cutting tools.

[0064] The machined surface 6 of the tube 20 is a smooth, continuous surface without irregularities.

[0065] Advantageously, when the machining tool 5 is in the operating position P2 , the smooth, continuous machining surface 6 without irregularities facilitates the plastic deformation of the tube 20 without removing material during the rotation of the machining tool 5 .

[0066] According to an embodiment, the heating device 7 heats the processing tool 5 by conduction, for example when they are in constant sliding contact.

[0067] Preferably, the heating device 7 comprises a metal body which is heated by means of one or more thermal resistors 8 .

[0068] According to another embodiment, the heating means 7 are of induction type.

[0069] According to an alternative embodiment, the heating means 7 are of the radiant type.

[0070] According to an aspect of the invention, the device 1 comprises a command and control unit U.

[0071] Preferably, the device 1 comprises at least one temperature sensor 8A which is designed to determine a temperature value of the heating device 7 or directly of the processing surface 6 .

[0072] The temperature sensor 8A is configured to send a signal to the command and control unit U that represents a predetermined temperature value of the heating device 7 or of the machining surface 6 .

[0073] The command and control unit U is designed to set the operating temperature of the heating device 7 or of the machining surface 6 as a function of the signal.

[0074] In other words, the command and control unit U receives a signal from the temperature sensor 8A relating to a measured temperature value of the heating device 7 or directly of the machined surface 6 and sets the temperature at which the heating device 7 operates based on this value.

[0075] The command and control unit U is designed to set the operating temperature of the heating device 7, for example to control starting and shutting down or to adjust the power.

[0076] It should be noted that, obviously, if the temperature of the machined surface 6 is not measured directly, indirectly setting the operating temperature of the heating device 7 according to the temperature of the heating device 7 will also result in controlling the temperature of the machined surface 6 .

[0077] Maintaining the heating device 7 at a predetermined temperature ensures that during the chamfering of the tube 20 the machining surface 6 of the machining tool 5 is maintained at a desired thermal state.

[0078] Preferably, the temperature sensor 8A is a thermocouple if it controls the temperature of the heating device 7 , and a pyrometer if it directly controls the temperature of the machining surface 6 .

[0079] According to one embodiment, the device 1 comprises a station 13 for heating at least a portion 24 of the first end 22 of each tube 20 positioned upstream of the chamfering element 4 .

[0080] In other words, the device 1 comprises a heating station 13 designed to heat at least a portion 24 of the first end 22 of the tube 20 before the tube 20 is chamfered.

[0081] Advantageously, heating both the portion 24 of the first end 22 of the tube 20 and the machining surface 6 of the machining tool 5 makes it possible to chamfer the tube 20 faster than in the prior art without removing debris, also for tubes 20 with unreduced thickness 25 (e.g. greater than 5 mm).

[0082] Furthermore, it should be noted that if the thickness of the tube 20 is considered to be small (eg thickness 25 less than or equal to 5 mm), the portion 24 of the first end 22 of the tube 20 does not need to be heated, but only the processing tool 5 needs to be heated.

[0083] In this way, the productivity of the device 1 is optimized since the chamfering process is accelerated without removing material (no preventive heating step is required or the time is significantly reduced); all this in compliance with the dimensional quality parameters of the tubes required by the corresponding regulations.

[0084] According to a preferred embodiment, the supporting element 10 comprises a cutting unit 3 .

[0085] In other words, according to a preferred embodiment, the cutting unit 3 and the chamfering element 4 are included in the same machining station of the device 1 .

[0086] The support unit 10 comprises a further displacement device 17 which is designed for radially displacing the cutting tool 16 relative to the pipe 20 between an operationally active position and an operationally inactive position, and vice versa.

[0087] The support element 10 is designed for rotating the cutting unit 3 about the axis A of the pipe 20 , in particular for producing at least one complete rotation of the cutting tool 16 about the axis A of the pipe 20 .

[0088] According to a preferred embodiment, the cutting tool 16 comprises a cutting edge 18 or a circular blade having an axis A2 and configured to rotate about its axis A2.

[0089] According to an embodiment not shown in the drawings, the device 1 comprises a plurality of chamfering elements 4 .

[0090] The support element 10 is configured to rotate each of the plurality of chamfered elements 4 about the axis A of the pipe 20 .

[0091] In particular, the supporting element 10 is configured to rotate each chamfering element 4 for a circumferential portion of the portion 24 of the first end 22 of the tube 20 in such a way that the sum of the circumferential portions covers at least the entire circumference of the portion 24 of the first end 22 of the tube 20 .

[0092] In particular, the support element 10 is configured for simultaneously rotating each chamfering element 4 for a circumferential portion of the portion 24 of the first end 22 of the pipe 20 .

[0093] In other words, each chamfering element 4 chamfers a portion of the portion 24 of the first end 22 of the pipe 20 , and the sum of the lengths of the portions chamfered by each chamfering element 4 corresponds at least to the total length of the circumference of the portion 24 of the first end 22 of the pipe 20 .

[0094] Advantageously, each chamfering element 4 of a circumferential portion of the tube 20 is rotated in such a way that the sum of the chamfered circumferential portions corresponds at least to the entire circumference of the tube 20, allowing the chamfering process to be accelerated.

[0095] In fact, rotating each chamfering element 4 simultaneously for a portion of the circumference of the tube 20 takes less time than performing a complete rotation around the tube 20 with a single chamfering element 4 .

[0096] According to an embodiment, the unit 12 for expanding the second end 23 of the tube 20 is positioned downstream of the cutting unit 3 .

[0097] More specifically, the term "flaring of a tubular member" refers to a specific flared-shaped widening of one end of a tubular member.

[0098] The invention also defines a method for manufacturing a pipe 20 made of thermoplastic material, in particular PVC-U.

[0099] The method includes the steps of supplying a continuously extruded tube 21, cutting the continuously extruded tube 21 into a plurality of tubes 20, each tube 20 having a first end 22 and a second end 23, and chamfering a portion 24 of the first end 22 of the corresponding tube 20.

[0100] Alternatively, the method comprises the step of supplying a series of individual tubes which are intended to be divided in turn into shorter lengths 20 .

[0101] The chamfering step comprises a step of plastically deforming the portion 24 of the first end 22 of the tube 20 using at least one heated machining tool 5 .

[0102] According to one aspect of the invention, the chamfering step comprises the step of bringing the heated machining tool 5 into contact with the portion 24 of the first end 22 of the tube 20 .

[0103] In other words, the chamfering step includes the step of radially moving the processing tool 5 relative to the pipe 20 from a first non-operating position P1 and an operating position P2, wherein the processing tool 5 is not engaged with the pipe 20, and the operating position P2 contacts the outer surface 26 of the portion 24 of the first end portion 22 of the pipe 20.

[0104] The chamfering step comprises the step of bringing the contact element 9 into contact with the portion 24 of the first end 22 of the tube 20 .

[0105] In other words, the chamfering step includes the step of moving the contact element 9 relative to the pipe 20 from a first non-operating position P1, in which the contact element 9 does not engage with the pipe 20, to an operating position P2, in which the contact element contacts the inner surface 27 of the portion 24 of the first end portion 22 of the pipe 20.

[0106] Preferably, the steps of bringing the machining tool 5 and the contact element 9 into contact with the portion 24 of the first end 22 of the tube 20 are performed sequentially with the contact element 9 being located in front of the tool 5 .

[0107] According to one aspect of the invention, the chamfering step comprises a step of relative movement of the heated machining tool 5 with respect to the tube 20 and vice versa.

[0108] Preferably, the step of relative movement of the heated processing tool 5 with respect to the pipe 20 comprises a corresponding rotation of the processing tool 5 around the pipe 20 and vice versa.

[0109] More specifically, during the chamfering step, the machining tool 5 moves in rotation around the tube 20 and vice versa.

[0110] In this way, the chamfering step allows the entire circumference of the portion 24 of the first end 22 of the tube 20 to be chamfered.

[0111] According to one embodiment, the step of chamfering the portion 24 of the first end portion 22 of the respective tube 20 is performed simultaneously with the cutting step.

[0112] Basically, according to this embodiment of the method, the portion 24 of the first end 22 of each tube 20 is thus also chamfered, without requiring a step of transferring the tube 20 to a subsequent processing station.

[0113] According to an alternative embodiment, the step of chamfering the first end 22 of the respective tube 20 takes place after the cutting step in a subsequent dedicated chamfering station.

[0114] According to this alternative embodiment, the method comprises a step of transferring the tube 20 performed during the cutting step to a chamfering station 14 different from the station comprising the cutting unit 3 .

[0115] More specifically, according to this alternative embodiment of the method, after the cutting step, after the step of transferring the tube 20 to the chamfering station 14 , the portion 24 of the first end 22 of the tube 20 is therefore also chamfered.

[0116] According to an aspect of the invention, the method comprises a step of heating the machining tool 5 before and / or during the chamfering step. The step of heating the machining tool 5 is in particular a step of heating the machining surface 6 of the machining tool 5 to a predetermined temperature, preferably between 50° C. and 200° C., depending on the nature of the thermoplastic material of the pipe.

[0117] The step of heating the machining tool 5 , in particular the step of heating the machining surface 6 , facilitates chamfering by plastic deformation of the tube 20 .

[0118] According to one embodiment (particularly for tubes with greater wall thickness), the method comprises a step of locally heating the portion 24 of the first end 22 of the tube 20 before the chamfering step.

[0119] In other words, the method also includes using a heated machining tool 5 during the chamfering step to heat the tube 20 before it is chamfered.

[0120] Heating the tube 20 before chamfering it using the chamfering tool 5, which is also heated, facilitates and accelerates the plastic deformation of the tube 20 without removing material during the chamfering step.

[0121] According to one embodiment, the method comprises a step of flaring the second end 23 of the tube 20 after the step of cutting the continuously extruded tube 21 .

[0122] The term “flared” of the second end 23 of the pipe 20 refers to a flared widened portion of the second end 23 to facilitate coupling with the chamfered first end 22 of another pipe 20 .

Claims

1. An apparatus for processing a pipe (20) made of thermoplastic material, comprising: Tubes (20), each of the tubes (20) extending along a longitudinal axis (A) and having a first end (22) and a second end (23); An element (4) for chamfering a portion (24) of the first end (22) of a corresponding pipe (20), comprising at least one machining tool (5) having a machining surface (6), The device (1) is characterized in that it comprises a heating device (7) associated with the machining tool (5), the heating device (7) being configured to heat the machining surface (6) of the machining tool (5) to a predetermined temperature.

2. The device according to the preceding claim, characterized in that The heating device (7) is in contact with at least part of the processing tool (5).

3. The device according to any one of the preceding claims, characterized in that The device comprises a command and control unit (U) and at least one temperature sensor (8A), wherein the at least one temperature sensor (8A) is configured to determine a temperature value of the heating device (7) and / or the processing surface (6) of the processing tool (5), and to send a signal representing the temperature value to the command and control unit (U), and the command and control unit (U) is configured to set an operating temperature of the heating device (7) according to the signal.

4. The device according to any one of the preceding claims, characterized in that The chamfering element (4) comprises a contact element (9) which is configured to cooperate with the processing tool (5); the processing tool (5) and the contact element (9) are configured to pass between a non-operating position (P1) and an operating position (P2), in which they are not engaged with the pipe (20), and in which they are in contact with corresponding surfaces (26, 27) of the portion (24) of the first end (22) of the pipe (20).

5. The device according to any one of the preceding claims, characterized in that The device comprises an element (10) for supporting the chamfering element (4), the element being configured for rotating the chamfering element (4) about an axis (A) of the pipe (20).

6. Device according to the preceding claim, characterized in that The support unit (10) comprises a movement device (11) configured to radially move the machining tool (5) relative to the pipe (20) from the non-operating position (P1) to the operating position (P2), and vice versa.

7. The device according to claim 5, characterized in that The supporting element (10) comprises a cutting unit (3) which is configured to form the tube (20).

8. The device according to any one of the preceding claims, characterized in that The device comprises a station (13) for heating at least said portion (24) of said first end (22) of each of said tubes (20) positioned upstream of said chamfering element (4).

9. The device according to any one of the preceding claims, characterized in that The machining surface (6) of the tube (20) has no cutter, and the machining tool (5) has a truncated cone shape with a larger base designed to come into contact with the heating device (7).

10. The device according to any one of the preceding claims, characterized in that The cutting tool (16) includes a cutting edge (18) or circular blade having an axis (A2) and configured to rotate about the axis (A2).

11. A method for processing a pipe (20) made of thermoplastic material, in particular PVC-U, the pipe (20) extending along a longitudinal axis (A) and having a first end (22) and a second end (23); The method comprises the step of chamfering a portion (24) of the first end (22) of the corresponding pipe (20), wherein the method comprises: The chamfering step includes the step of plastically deforming the portion (24) of the first end (22) of the tube (20) using at least one heated machining tool (5).

12. The method according to the preceding claim, characterized in that The chamfering step includes the steps of bringing the heated processing tool (5) into contact with the portion (24) of the first end (22) of the pipe (20), and moving the heated processing tool (5) relative to the pipe (20).

13. The method according to the preceding claim, characterized in that The step of relative movement of the heated processing tool (5) relative to the pipe (20) comprises relative rotation of the processing tool (5) around the pipe (20).

14. The method according to any one of claims 11 to 13, characterized in that The step of chamfering the portion (24) of the first end (22) of the respective tube (20) is performed simultaneously with the step of cutting the continuously extruded tube (21) at the first end (22).

15. The method according to any one of claims 11 to 13, characterized in that The step of chamfering said portion (24) of said first end (22) of the respective tube (20) occurs after the step of cutting the continuously extruded tube (21).

16. The method according to any one of claims 13 to 15, characterized in that The method comprises the step of heating the machining tool (5) before and / or during the chamfering step.

17. The method according to any one of claims 13 to 16, characterized in that The method includes the step of locally heating the portion (24) of the first end (22) of the tube (20) prior to the chamfering step.

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