FLAME COATING MACHINE AND METHOD

Abstract

A flame coating machine for coating field joints of a pipeline has a flame spray system having two flame spray units configured for heating and/or coating with a thermoplastic polymer an annular junction portion and two annular end portions of an existing coating delimiting the annular junction portion; a control system having two temperature sensors configured for acquiring temperature values along the surface collectively defined by the annular junction portion and the annular end portions, and a control unit configured for actuating the flame spray unit in a polymer flame spraying mode or in a flame heating mode as a function of the detected temperature values and at least one threshold value.

Claims

1-15. (canceled)

16: A flame coating machine configured to coat a field joint of a pipeline, the flame coating machine comprising: a flame spray system comprising a flame spray unit configured to at least one of: (i) heat an annular junction portion and two annular end portions of an applied coating that delimits the annular junction portion, and (ii) coat the annular junction portion and the two annular end portions with a thermoplastic polymer; and a control system comprising: a temperature sensor configured to acquire a plurality of temperature values along a surface defined by the annular junction portion and the two annular end portions, and a control unit configured to actuate, based on the acquired temperature values and at least one threshold value, the flame spray unit in one of: a polymer flame spraying mode and a flame heating mode.

17: The flame coating machine of claim 16, wherein the control system comprises a first position sensor configured to acquire a position of the flame spray unit with respect to the surface, and a second position sensor configured to acquire a position of the temperature sensor with respect to the surface.

18: The flame coating machine of claim 17, wherein the control unit comprises a microprocessor configured to associate each acquired temperature value to an area of the surface, and compare each temperature value with a respective threshold value associated with that area of the surface.

19: The flame coating machine of claim 16, wherein the temperature sensor is one of a pyrometer and a thermal imaging camera.

20: The flame coating machine of claim 16, further comprising a guide system selectively clampable to the pipeline within a designated distance of the annular junction portion and configured to advance the flame spray unit and the temperature sensor along an annular path and a linear path to cover the surface.

21: The flame coating machine of claim 20, further comprising two flame spray units and two temperature sensors.

22: The flame coating machine of claim 21, wherein the guide system comprises: a main frame selectively clampable to the pipeline; a rotor selectively rotatable with respect to the main frame and about the pipeline; and a carriage moveable along the rotor parallel to an axis of rotation of the rotor.

23: The flame coating machine of claim 22, wherein the carriage comprises a frame and two supports arranged at 1800 apart about the axis of rotation of the rotor, each support configured to support one of the flame spray units and one of the temperature sensors.

24: The flame coating machine of claim 23, wherein each support is adjustable in a radial direction along the main frame with respect to the axis of rotation of the rotor.

25: The flame coating machine of claim 16, wherein the flame spray system comprises a fuel supply device configured to supply a fuel to the flame spray unit and a polymer supply device configured to supply the thermoplastic polymer to the flame spray unit.

26: A method of flame coating a field joint of a pipeline, the method comprising: at least one of: (i) heating, by a flame spray unit, an annular junction portion and two annular end portions of an applied coating that delimits the annular junction portion, and (ii) coating, by the flame spray unit, the annual junction portion and the two annular end portions with a thermoplastic polymer; acquiring, by a temperature sensor, a temperature value along a surface defined by the annular junction portion and the two annular end portions; and actuating, based on the acquired temperature value and a threshold value, the flame spray unit in one of: a polymer flame spraying mode and a flame heating mode.

27: The method of claim 26, further comprising acquiring a position of the flame spray unit and a position of the temperature sensor with respect to the surface.

28: The method of claim 27, further comprising: associating each acquired temperature value to an area of the surface; and comparing each temperature value with a respective threshold value associated with that area of the surface.

29: The method of claim 26, further comprising advancing the flame spray unit and the temperature sensor along an annular path and a linear path to cover the surface.

30: The method of claim 26, further comprising: selectively supplying fuel to the flame spray unit, and selectively supplying the thermoplastic polymer to the flame spray unit.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0034] Additional characteristics and advantages of the present disclosure will become clear from the following description of its embodiments, with reference to the accompanying figures, wherein:

[0035] FIG. 1 is an elevated lateral view, with parts in cross-section and parts removed for clarity, of a pipeline to which a polymer material is applied with a flame spray unit;

[0036] FIG. 2 is an elevated lateral view, with parts shown in cross-section and parts removed for clarity, of the pipeline in FIG. 1 and provided with a field joint coating;

[0037] FIG. 3 is a perspective view, with parts removed for clarity and parts in cross-section, of a flame coating machine made in accordance with the present disclosure;

[0038] FIG. 4 is a perspective view, with parts removed for clarity and on an enlarged scale, of the machine in FIG. 3; and

[0039] FIG. 5 is a schematic view, with parts in cross-section and parts removed for clarity, of the machine in FIG. 3 coupled to a pipeline as shown in FIG. 1.

DETAILED DESCRIPTION

[0040] In FIGS. 1 and 2, the number 1 indicates a pipeline as a whole, which extends along a longitudinal axis A. In the case shown in FIG. 1, the pipeline 1 comprises two sections of pipe 2 aligned along the longitudinal axis A and joined together. Each pipe section 2 comprises a metal cylinder 3; a coating 4 made of polymer material, generally polyethylene or polypropylene, which is arranged in contact with the metal cylinder 3 and has the function of protecting the metal cylinder 3 from corrosion.

[0041] Each section of pipe 2 has two opposite uncoated ends 5 (only one of which is shown in FIG. 1), which have a chamfer 6. Two successive sections of pipe 2, which are aligned along the longitudinal axis A, are arranged with the uncoated ends 5 facing each other and they are welded together, possibly in several welding passes, so as to make an annular weld seam 7 between the two sections of pipe 2. The two sections of welded pipe 2 define an annular junction portion 8, which extends along the longitudinal axis A between the two chamfers 6 of the coating 4 and comprises the annular weld seam 7.

[0042] In general, the repetition of the joints of sections of pipe 2 makes it possible to make the pipeline 1. With reference to the present description, pipeline 1 is also understood to mean the pipeline under construction consisting, for example, of only two sections of pipe 2 joined together.

[0043] The joining of the sections of pipe 2 also involves, in addition to the welding of the metal cylinders 3, the making of a seamless coating of the existing coatings 4. This operation involves applying a polymer material by a flame spray unit 9 around and along the annular junction portion 8 and around and along two annular end portions 10 of the coating 4.

[0044] The application of the polymer material generally requires operations to prepare the face of the annular junction portion 8 and of the end portions 10, in order to facilitate the adhesion of a field joint coating 11 (FIG. 2). These operations consist in cleaning, for example, via blasting, and in heating, for example by induction, the annular junction portion 8.

[0045] Prior to the application of the field joint coating 11 (FIG. 2), a thin layer of polymer material, in particular epoxy material, can be applied to the annular junction portion, which has the function of a primer, as well as a layer of polymer adhesive.

[0046] The flame spray unit 9 is guided along an axis parallel to the longitudinal axis A and along the plane defined by that longitudinal axis A so as to repeatedly “wipe” the whole surface on which the polymer material has to be applied.

[0047] With reference to FIG. 2, a field joint coating 11 is shown, which has been made by progressive addition until reaching the required thickness and covering/adhering to the annular junction portion 8 and to the annular end portions 10.

[0048] With reference to FIG. 3, the number 12 indicates a flame coating machine configured to make the field joint coating 11 (FIG. 2). The machine 12 comprises a guide system 13 configured to be clamped to the pipeline 1 (FIG. 1) and to guide one or more flame spray units 9 along the annular junction portion 8 and the annular end portions 10 (FIG. 1); a flame spray system 14 configured to feed fuel and polymer powder material to the spray unit 9; and a control system 15 configured to control the position of the flame spray unit 9 and the operating status of the flame spray unit 9.

[0049] The guide system 13 comprises a frame 16 that can be clamped to the pipeline 1 and comprising two U-shaped structures 17 facing each other and configured to be arranged, in use, on the sides opposite an annular junction portion (FIG. 1); a rotor 18, which is supported in a rotatable manner by the frame and by the two U-shaped structures 17; and a carriage 19, which is guided along the rotor 18.

[0050] With reference to FIG. 4, the rotor 18 is shaped like an open cylindrical cage so that the rotor 18 can be arranged around the pipeline 1 (FIG. 1) via radial access together with the frame 16. In more detail, the rotor 18 comprises two annular arch-shaped sliders 20, which are facing and parallel to each other, which extend for a circular arch greater than 180°, and which are guided by their respective U-shaped structures 17, only one of which is shown in FIG. 3; and bars 21 which connect the sliders 20 to each other.

[0051] The carriage 19 is mounted to slide along at least two bars 21 and comprises a frame 22; and, in the example shown, two supports 23, each of which is configured to house a flame spray unit 9 (FIG. 1) and is adjustable with respect to the frame 22 in a transverse direction to the bars 21 and substantially radial when the guide system 13 is coupled to the pipeline 1 (FIG. 1). In the example shown, the two supports 23 are arranged at 180° from each other.

[0052] The guide system 13 also comprises an actuator 24 configured to rotate the rotor 18 via a transmission comprising a sprocket 25 and a toothed annular sector 26 coupled to one of the sliders 20; and an actuator 27 configured to advance the carriage 19 along the rotor 18 by a transmission comprising a worm gear 28; a worm screw 29; and a nut 30 associated with the carriage 19.

[0053] With reference to FIG. 5, the machine 12 is clamped to the pipeline in such a way that the rotation axis A1 of the rotor 18 essentially coincides with the longitudinal axis A of the pipeline 1.

[0054] The flame spray system 14, in addition to the above-mentioned flame spray units 9, comprises a fuel supply device 31 and a polymer supply device 32. Generally, the fuel is LPG and the polymer polypropylene powder.

[0055] The spray system 14 is a product available on the market, such as, for example, those made by the company IBIX S.r.l. La Viola no. 4,1-48022 Santa Maria in Fabriago, Lugo (RA), Italy.

[0056] With reference to FIG. 5, the control system 15 comprises a control unit 33 configured to control the operating parameters of the guide system 13 and the flame spray system 14; temperature sensors 34 configured to detect the external surface temperature of the pipeline 1; position sensors 35 to detect the position of the carriage 19 and the flame spray units 9.

[0057] In practice, the control unit 33 controls the guide system 13, the flame spray system 14 and the interactions between the guide system 13 and the flame spray system 14.

[0058] The control unit 33 comprises a microprocessor configured to compare input data with predefined parameters, process the data, and emit signals for monitoring the guide system 13 and flame spray system 14. In particular, the flame spray system 14 has a rest state and two operating states: a first operating state involves emitting only the flame for heating a surface, while a second operating state involves emitting the flame together with the polymer to make a coating via the flame spray system 14. The control system 15 selects the rest state and one of the two operating states of the flame spray system 14 as a function of the temperature detected by the temperature sensors 34 and the reference parameters.

[0059] In more detail, the temperature sensors 34 are configured to detect the surface temperature of the annular junction portion 8 and the annular end portions 10 and can be pyrometers or cameras mounted on supports 23. The actuators 24 and 27 enable temperature sensors 34 to be arranged on the whole surface collectively defined by the annular junction portion 8 and by the annular end portions 10, while the position sensors 35, which enable a particular area of the surface to be associated with a corresponding temperature value acquired by the temperature sensors 34. In this case, the position sensors can be encoders associated with the actuators 24 and 27.

[0060] The microprocessor compares the temperature values with the threshold values: if the temperature values of an area on the surface are below certain threshold values, a signal is emitted that activates one or more flame spray units 9 in the flame-only operating state to heat the area where the temperature does not meet the temperature requirements to proceed with the application of the flame coating.

[0061] If, on the other hand, the whole surface that has to be coated meets the temperature requirements, then the flame spray system 14 is set to the operating state of the flame polymer application.

[0062] The threshold values may vary as a function of the area of the surface, particularly as a function of whether the surface is defined by the annular junction portion 8 or by the annular end portions 10.

[0063] The spray units 9 are guided by the guide system 13 along a path that results from the combination of an annular path determined by the rotation of the rotor 18 around the pipeline 1 and by a linear path of the carriage 19 along the rotor 18. The combination of the annular path and the linear path enables the annular junction portion 8 and the annular end portions 10 to be fully coated.

[0064] In the case shown, the machine 12 comprises two flame spray units 9 mounted on the carriage 19 and arranged at 180° to each other. As a result, 180° rotations of the rotor 18 are sufficient to coat the whole annular surface.

[0065] The supports 23 are adjustable in the radial direction and can adapt the machine 12 to the diameter of the pipeline 1 and, in particular, to enable the positioning of the flame spray units 9 at a distance determined by the surface so that the flame is always at the optimal distance of use from the surface.

[0066] The present disclosure extends to additional variants which are not explicitly described and which fall within the scope of protection of the claims. That is, the present disclosure also covers embodiments that are not described in the detailed description above as well as equivalent embodiments that are part of the scope of protection set forth in the claims. Accordingly, various changes and modifications to the presently disclosed embodiments will be apparent to those skilled in the art.