Induction-fused thermoplastic pipe

Abstract

A pipe (110) includes an inner thermoplastic pipe (220) and an outer thermoplastic layer (240) wrapped around the inner thermoplastic pipe (220) and fused therewith. The pipe (220) also includes an induction heatable material (230) within or between at least one of the inner thermoplastic pipe (220) and the outer thermoplastic layer (240). A method of manufacturing the pipe (110) involves wrapping the outer thermoplastic layer (240) around the inner thermoplastic pipe (220), providing the inner thermoplastic pipe (220), the outer thermoplastic layer or a separate layer with induction heatable material (230), and heating with an induction heater to fuse the inner thermoplastic pipe (220) with the outer thermoplastic layer (240). The induction heatable material (230) may be porous or permeable, and may take the form of a carbon fibre mesh or a metal foil or wire made of iron or copper.

Description

15 between one or more layers. At least a portion of the IHCM 230 may be electrically conductive, which may allow for the formation of currents within the IHCM 230. The IHCM 230 may include a metal, such as iron or copper. The IHCM 230 may include a metalloid or nonmetal, such as carbon. In an example, the IHCM 230 may be carbon fiber and may include one or more of a carbon fiber 20 filament, strand, mesh, mat, or fabric. In an example, the IHCM 230 may include distributed particles in one or more of the inner thermoplastic pipe 220 or the outer layer of thermoplastic material 240.

[026] The IHCM 230 may be configured to provide heat through induction heating. The IHCM 230 may be configured to provide heat for fusing 25 the inner thermoplastic pipe 220 and the outer layer of thermoplastic material 240. The IHCM 230 may be included within one or more regions of the inner thermoplastic pipe 220. Alternatively or additionally, the IHCM 230 may be included within one or more regions of the one or more outer layers of thermoplastic material 240. The IHCM 230 may be applied to an outer layer or 30 face of the inner thermoplastic pipe 220 or an inner layer or face of the one or more outer layers of thermoplastic material 240.

[027] In an example, the IHCM 230 may include a distinct layer between the inner thermoplastic pipe 220 and the outer layer of thermoplastic material 240. For example, the IHCM 230 may be one or more of a permeable mesh or fabric 6 2024276628   04 Aug 2026 applied to the inner thermoplastic pipe 220 or between layers of the outer layer of thermoplastic material 240. The IHCM 230 might not be solid but may have pores or gaps, such as may allow a material to flow or seep through the IHCM 230.

[028] At least a portion of the pipe 110 may be conductive to electricity 5 along a length of the pipe 110, which may be due to the presence of the IHCM 230. For example, there may be a relatively low resistance path for electrons to travel along a length of pipe 110. This may allow the pipe 110 to be electrically grounded, which may lower the risk of a static discharge igniting a fire.

[029] FIG. 3 is a cross-sectional view of an example of a portion of the 10 pipe 110 of FIG. 2. FIG. 3 shows the inner thermoplastic pipe 220, the one or more layers of thermoplastic material 240, and the IHCM 230. FIG. 3 shows that an inner surface of the inner thermoplastic pipe 220 defines the bore 250 of the pipe 110. FIG. 3 also shows two outer layers of thermoplastic material 240, including 2 regions containing an IHCM 230. In an example, the IHCM 230 may 15 be applied to a face of the thermoplastic material 240, or the outer layer of thermoplastic material 240 may be manufactured with an IHCM 230. In an example, the IHCM 230 may be a distinct layer included between the inner thermoplastic pipe 220 and the outer layer of thermoplastic material 240, as well as a distinct layer between respective outer layers of thermoplastic material 240. 20

[030] FIGS. 4-5 illustrate a process for forming a thermoplastic pipe. In particular, FIG. 4 is a flow chart showing an example of a method for manufacturing portions of a pipe. FIG. 5 is a perspective view of an example of portions of a pipe 110 being manufactured and portions of the system for manufacturing the pipe. As shown in FIG. 5, an inner thermoplastic pipe 220 may 25 be wrapped 410 with an outer layer of thermoplastic material 240, where at least one of the inner thermoplastic pipe 220, the outer layer of thermoplastic material 240, or a separate layer provides an induction heating compatible material (IHCM) 230. Where the IHCM is a separate material, the process may include wrapping the inner thermoplastic pipe 220 with the IHCM material or wrapping 30 an already-applied outer layer with the IHCM material. In the example of FIG. 5, the IHCM 230 is shown as a distinct layer applied with the outer layer of thermoplastic material 240. However, the IHCM 230 may be applied separately from the outer layer of thermoplastic material 240. In an example, the IHCM 230 may not be required to be applied as a separate layer because the IHCM 230 may 7 2024276628   04 Aug 2026 already be contained within at least one of the inner thermoplastic pipe 220 or the outer layer of thermoplastic material 240 (e.g., previously embedded or otherwise incorporated into the inner thermoplastic pipe 220 or the outer layer of thermoplastic material 240). 5

[031] The outer layer of thermoplastic material 240 may be wrapped onto the inner thermoplastic pipe 220 in at least one of a tape, strand, or sheet. The outer layer of thermoplastic material 240 may be wrapped in the direction of arrows 520. For example, two separate outer layers of thermoplastic material 240 may be wrapped onto the inner thermoplastic pipe 220 in opposing directions such 10 that the layers overlap. In an example, a portion of the separate layers may overlap with themselves. In an example, the separate layers may equally cover each portion of the inner thermoplastic pipe 220. In an example, the separate layers may not cover each portion of the inner thermoplastic pipe 220, and there may be gaps between respective wraps of a given layer. 15

[032] There may be an IHCM 230 near each seam between one or more of the inner thermoplastic pipe 220 or the outer layers of thermoplastic material 240. In an example, a single IHCM 230 layer may be used to fuse more than one seam, such as by heating up a specified portion of the pipe 110. In an example, each of the separate layers may be applied with an IHCM 230. In an example, less 20 than all of the separate layers may be applied with an IHCM 230. Including an IHCM 230 either as a separate layer, on the face of, or within each separate layer of the outer layer of thermoplastic material 240 may help to ensure that there is an IHCM near every seam or junction of separate thermoplastic layers. This may help reduce the amount of heat that may be needed to form the pipe by helping to 25 ensure that every thermoplastic junction has a nearby IHCM 230.

[033] The pipe 110 may be heated 420 using an induction heater to fuse the inner thermoplastic pipe 220 with the outer layer of thermoplastic material 240. For example, the pipe may be passed through an induction heater including an induction heating coil 500 and an induction heating driver. 30

[034] The induction heating coil 500 may be wrapped around a portion of the pipe 110. The induction heating coil 500 may not be required to touch the pipe 110 or the IHCM 230 to heat the IHCM 230. The induction heating coil 500 may be a conductive coil, such as may include a conductive coil of copper or other metal. The induction heating coil 500 may be driven by an induction heating 8 2024276628   04 Aug 2026 driver, which as may produce an alternating current of a specified amplitude and frequency. In an example, the frequency of the alternating current may be relatively high, such as may include between 1000 Hz and 100,000 Hz, between 5,000 Hz and 50,000 Hz, or 10,000 Hz, as illustrative examples. The induction 5 heating coil 500 may induce a current in at least a portion of the IHCM 230 which may cause the IHCM 230 to heat up due to resistive losses. The heat from the IHCM 230 may be passed by conduction to the surrounding thermoplastic material, which may result in one or more pieces of thermoplastic material fusing together. 10

[035] The pipe may travel in the direction 510 at a specified speed such as may allow the induction heating coil 500 to heat the IHCM 230 and fuse respective layers of the pipe 110. The speed of travel in direction 510 may be configurable, which may allow an operator or computer to adjust the manufacturing process. Additionally or alternatively, the power output and / or 15 other parameters of the induction heating coil 500 may be configurable, which may further allow an operator or computer to adjust the manufacturing process. In an example, one or more of the speed of travel or the parameters of the induction heating coil 500 may be adjusted based upon a monitored condition of the pipe 110, which, for example, may include the temperature of the pipe exiting 20 the induction heating coil 500.

[036] FIG. 4 illustrates an example of a method for manufacturing pipe 110. The shown order of steps is not intended to be a limitation on the order the steps are performed in. In an example, two or more steps may be performed simultaneously or at least partially concurrently. In an example, one or more steps 25 may be omitted. In an example, one or more steps may be added.

[037] Step 410 and step 420 may be performed simultaneously or at least partially concurrently. For example, the outer layer of thermoplastic material 240 may be wrapped onto a portion of the inner thermoplastic pipe 220 at the same time as at least one of (1) the portion being wrapped or (2) another portion of the 30 pipe 110 is being heated by the induction heating coil 500. In the example of FIG. 5, one portion of the inner thermoplastic pipe 220 is wrapped with the outer layer of thermoplastic material 240 while a previously wrapped portion of the inner thermoplastic pipe 220 is heated using the induction heating coil 500. 9 2024276628   04 Aug 2026

[038] The pipe 110 may be manufactured in an ongoing or substantially continuous manufacturing or production process. The ongoing manufacturing process may include manufacturing a specified length of pipe without a significant stoppage or break in the manufacturing process. The wrapping of the 5 inner thermoplastic pipe 220 may occur in a substantially continuous fashion. The heating of the pipe 110 by the induction heating coil 500 may also occur in a substantially continuous fashion. For example, the pipe 110 may move at a specified speed longitudinally in the direction 510 to create a continuous production process. The pipe 110 may move continuously for a portion of the 10 manufacturing process. While the pipe 110 is moving, the induction heating coil 500 may heat different portions of the pipe 110. For example, when a portion of the pipe 110 enters the induction heating coil 500, it may begin being heated and when a portion of the pipe 110 exits the induction heating coil 500, it may have been heated enough to allow the layers to fuse. 15

[039] While the pipe is traveling in direction 510, the wrapping of the outer layer of thermoplastic material 240 may be occurring substantially continuously in the direction of the arrows 520. This may result in the inner thermoplastic pipe 220 being wrapped consistently by the outer layer of thermoplastic material 240. The continuous production process of the pipe 110 20 may be one or more of more efficient, quicker, or may result in a product that is more consistent or has more desirable properties (e.g. strength and durability) than a batch-manufactured pipe.

[040] In an example, the pipe 110 may be heated using both an induction heater and another heat source. For example, the pipe 110 may be heated using 25 radiant or convention heating as well as induction heating. In an example, the pipe 110 may be preheated using a radiant heater and then passed through the induction heating coil 500 to accomplish the final fusing of the respective layers. In an example, the preheating process may be accomplished by using one or more of a warm manufacturing environment, a preheated inner thermoplastic pipe 220, a 30 preheated outer layer of thermoplastic material 240, or a preheated IHCM 230. In an example, the inner thermoplastic pipe 220 may be extruded in a substantially continuous process along with the manufacturing of the pipe 110, which may provide a degree of heat for the fusing. In an example, the pipe 110 may be cooled at one or more points in the manufacturing process. For example, the pipe may be 10 2024276628   04 Aug 2026 cooled to solidify one or more seams before additional layers are added or another manufacturing process begins.

[041] The IHCM 230 may be infused or embedded in the inner thermoplastic pipe 220, the outer layer of thermoplastic material 240, or both. In 5 a case where the IHCM 230 is applied as a distinct layer between the inner thermoplastic pipe 220 and the outer layer of thermoplastic material 240, the IHCM 230 may be permeable to allow thermoplastic material to seep through the IHCM 230. For example, one or more of the inner thermoplastic pipe 220 or the outer layer of thermoplastic material 240 may seep through the IHCM 230 to fuse 10 with another layer.

[042] In a case where the IHCM 230 is included in the outer layer of thermoplastic material 240, the IHCM 230 may be infused within the outer layer of thermoplastic material 240. For example, carbon fibers in the form of a strand, mat, or fabric may be infused in a thermoplastic material to form the outer layer 15 of thermoplastic material 240. In an example, the outer layer of thermoplastic material 240 may be formed by impregnating an IHCM 230 with thermoplastic. For example, liquid thermoplastic may be poured over an IHCM and impregnate the IHCM to form the outer layer of thermoplastic material 240. In an example, the IHCM 230 can be a metal powder that is infused, embedded, or impregnated 20 into one or more portions of the pipe 110.

[043] The method of FIG. 4 may include supplying the IHCM 230 in at least one of a specified quantity or a specified form to result in a pipe 110 that is electrically conductive. For example, the IHCM 230 may be supplied in a sufficient quantity to result in a pipe of a desired level of conductivity. In an 25 example, a specified form of IHCM may result in a conductive pipe, such as a fabric or strand that spans a length of pipe.

[044] The present devices and methods are believed to apply to a range of potential applications, which is not limited to spoolable plastic pipe. For example, these devices and methods may apply to non-spoolable pipe that is 30 manufactured and transported in straight sections. For example, these devices and methods may apply to a pipe that is not thermoplastic but whose materials may behave similar to a thermoplastic (i.e. fusing when heated). For example, these devices and methods may apply to a device that is not a pipe, but may be a tank, tube, or other similar device that includes a fused inner portion and outer portion. 11 2024276628   04 Aug 2026

[045] Examples:

[046] Example 1 is a pipe comprising: an inner thermoplastic pipe; an outer layer of thermoplastic material wrapped around the inner thermoplastic pipe, wherein the outer layer of thermoplastic material is fused with the inner 5 thermoplastic pipe; and an induction heating compatible material (IHCM) within or between at least one of the inner thermoplastic pipe or the outer layer of thermoplastic material.

[047] In Example 2, the subject matter of Example 1 optionally includes wherein the IHCM is configured to provide heat through induction heating for 10 fusing the inner thermoplastic pipe and the outer layer of thermoplastic material.

[048] In Example 3, the subject matter of any one or more of Examples 1-2 optionally include wherein the outer layer of thermoplastic material includes at least one of a strand, tape, or sheet.

[049] In Example 4, the subject matter of any one or more of Examples 15   1-3 optionally include wherein the IHCM includes a distinct layer between the inner thermoplastic pipe and the outer layer of thermoplastic material.

[050] In Example 5, the subject matter of Example 4 optionally includes wherein the IHCM is permeable to allow at least one of the inner thermoplastic pipe or the outer layer of thermoplastic material to seep through the IHCM and 20 fuse with at least one of the inner thermoplastic pipe or the outer layer of thermoplastic material.

[051] In Example 6, the subject matter of any one or more of Examples 1-5 optionally include wherein the IHCM is within the outer layer of thermoplastic material. 25

[052] In Example 7, the subject matter of any one or more of Examples 1-6 optionally include wherein the IHCM includes carbon fiber.

[053] In Example 8, the subject matter of any one or more of Examples 1-7 optionally include wherein the pipe is electrically conductive.

[054] In Example 9, the subject matter of any one or more of Examples 30    1-8 optionally include wherein the pipe is reinforced with fiberglass.

[055] Example 10 is a method of manufacturing a pipe, the method comprising: wrapping an inner thermoplastic pipe with an outer layer of thermoplastic material, wherein at least one of the inner thermoplastic pipe, the outer layer of thermoplastic material, or a separate layer provides an induction 12 2024276628   04 Aug 2026 heating compatible material (IHCM); and using an induction heater, heating the IHCM to fuse the inner thermoplastic pipe with the outer layer of thermoplastic material.

[056] In Example 11, the subject matter of Example 10 optionally 5 includes applying a material including an IHCM as a distinct layer between the inner thermoplastic pipe and an outer layer of thermoplastic material.

[057] In Example 12, the subject matter of Example 11 optionally includes applying the IHCM as at least one of a tape, strand, sheet, or distributed particle. 10

[058] In Example 13, the subject matter of any one or more of Examples 11-12 optionally include wherein the IHCM is permeable to allow at least one of the inner thermoplastic pipe or the outer layer of thermoplastic material to seep through the IHCM and fuse with at least one of the inner thermoplastic pipe or the outer layer of thermoplastic material. 15

[059] In Example 14, the subject matter of any one or more of Examples 10-13 optionally include wherein the IHCM is infused in the outer layer of thermoplastic material before the wrapping the inner thermoplastic pipe with the outer layer of thermoplastic material.

[060] In Example 15, the subject matter of Example 14 optionally 20 includes wherein the outer layer of thermoplastic material is manufactured by impregnating an IHCM with a thermoplastic material.

[061] In Example 16, the subject matter of any one or more of Examples 10-15 optionally include applying the IHCM to a face of the outer layer of thermoplastic material before the wrapping the inner thermoplastic pipe with the 25 outer layer of thermoplastic material.

[062] In Example 17, the subject matter of any one or more of Examples 10-16 optionally include wherein the wrapping the inner thermoplastic pipe with the outer layer of thermoplastic material includes wrapping the inner thermoplastic pipe with at least one of a strand, tape, or sheet. 30

[063] In Example 18, the subject matter of any one or more of Examples 10-17 optionally include supplying the IHCM in at least one of a sufficient quantity or specified form such that the pipe is electrically conductive. 13 2024276628   04 Aug 2026

[064] In Example 19, the subject matter of any one or more of Examples 10-18 optionally include wherein the IHCM is located at or near a seam between the inner thermoplastic pipe and the outer layer of thermoplastic material.

[065] In Example 20, the subject matter of any one or more of Examples 5   10-19 optionally include continuously moving the pipe through the induction heater longitudinally to create a continuous production process.

[066] Example 21 is at least one machine-readable medium including instructions that, when executed by processing circuitry, cause the processing circuitry to perform operations to implement of any of Examples 1-20. 10

[067] Example 22 is an apparatus comprising means to implement of any of Examples 1-20.

[068] Example 23 is a system to implement of any of Examples 1-20.

[069] Example 24 is a method to implement of any of Examples 1-20.

[070] Each of the non-limiting aspects above can stand on its own or can 15 be combined in various permutations or combinations with one or more of the other aspects or other subject matter described in this document.

[071] The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the 20 invention can be practiced. These embodiments are also referred to generally as “examples.” Such examples can include elements in addition to those shown or described. However, the present inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the present inventors also contemplate examples using any combination or permutation of 25 those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein.

[072] In the event of inconsistent usages between this document and any documents so incorporated by reference, the usage in this document controls. 30

[073] In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In this document, 14 2024276628   04 Aug 2026 the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, composition, formulation, or process that includes elements in addition to 5 those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc., are used merely as labels, and are not intended to impose numerical requirements on their objects.

[074] Method examples described herein can be machine or computer- 10 implemented at least in part. Some examples can include a computer-readable medium or machine-readable medium encoded with instructions operable to configure an electronic device to perform methods as described in the above examples. An implementation of such methods can include code, such as microcode, assembly language code, a higher-level language code, or the like. 15 Such code can include computer readable instructions for performing various methods. The code may form portions of computer program products. Such instructions can be read and executed by one or more processors to enable performance of operations comprising a method, for example. The instructions are in any suitable form, such as but not limited to source code, compiled code, 20 interpreted code, executable code, static code, dynamic code, and the like.

[075] Further, in an example, the code can be tangibly stored on one or more volatile, non-transitory, or non-volatile tangible computer-readable media, such as during execution or at other times. Examples of these tangible computer-readable media can include, but are not limited to, hard disks, removable magnetic 25 disks, removable optical disks (e.g., compact disks and digital video disks), magnetic cassettes, memory cards or sticks, random access memories (RAMs), read only memories (ROMs), and the like.

[076] The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects 30 thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in 15 2024276628   04 Aug 2026 the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, 5 the following claims are hereby incorporated into the Detailed Description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full 10 scope of equivalents to which such claims are entitled. 16

Claims

1. A pipe comprising:an inner thermoplastic pipe;5          an outer layer of thermoplastic material wrapped around the innerthermoplastic pipe, wherein the outer layer of thermoplastic material is fused with the inner thermoplastic pipe; andan induction heating compatible material (IHCM) comprising a distinct layer between the inner thermoplastic pipe and the outer layer of thermoplastic10 material, wherein the IHCM is permeable to allow at least one of the inner thermoplastic pipe or the outer layer of thermoplastic material to seep through the IHCM and fuse with at least one of the inner thermoplastic pipe or the outer layer of thermoplastic material.15   2.     The pipe of claim 1, wherein the IHCM is configured to provide heatthrough induction heating for fusing the inner thermoplastic pipe and the outer layer of thermoplastic material.

3. The pipe of any one of the preceding claims, wherein the outer layer of20 thermoplastic material includes at least one of a strand, tape, or sheet.

4. The pipe of any one of the preceding claims, further comprising an IHCMwithin the outer layer of thermoplastic material.25   5.     The pipe of claim 1 or claim 4, wherein the IHCM includes carbon fiber.

6. The pipe of any one of the preceding claims, wherein the pipe is electricallyconductive.30   7.     The pipe of any one of the preceding claims, wherein the pipe is reinforcedwith fiberglass.

8. A method of manufacturing a pipe, the method comprising:2024276628   04 Aug 2026wrapping an inner thermoplastic pipe with an outer layer of thermoplastic material, wherein at least one of the inner thermoplastic pipe, the outer layer of thermoplastic material, or a separate layer provides an induction heating compatible material (IHCM), including supplying the IHCM in at least one of a5 sufficient quantity or specified form such that the pipe is electrically conductive along a length of the pipe; andusing an induction heater, heating the IHCM to fuse the inner thermoplastic pipe with the outer layer of thermoplastic material.10   9.     The method of claim 8, further comprising applying a material including anIHCM as a distinct layer between the inner thermoplastic pipe and an outer layer of thermoplastic material.

10. The method of any one of claims 8 to 9, further comprising applying the 15 IHCM as at least one of a tape, strand, sheet, or distributed particle.

11. The method of any one of claims 9 to 10, wherein the IHCM is permeable to allow at least one of the inner thermoplastic pipe or the outer layer of thermoplastic material to seep through the IHCM and fuse with at least one of the 20 inner thermoplastic pipe or the outer layer of thermoplastic material.

12. The method of claim 8, wherein the IHCM is infused in the outer layer of thermoplastic material before the wrapping the inner thermoplastic pipe with the outer layer of thermoplastic material.2513. The method of claim 12, wherein the outer layer of thermoplastic material is manufactured by impregnating an IHCM with a thermoplastic material.

14. The method of any one of claims 8 to 11, further comprising applying the30 IHCM to a face of the outer layer of thermoplastic material before the wrapping the inner thermoplastic pipe with the outer layer of thermoplastic material.2024276628   04 Aug 202615. The method of claim 8, wherein the wrapping the inner thermoplastic pipe with the outer layer of thermoplastic material includes wrapping the inner thermoplastic pipe with at least one of a strand, tape, or sheet.5   16. The method of claim 8, wherein the IHCM is located at or near a seambetween the inner thermoplastic pipe and the outer layer of thermoplastic material.

17. The method of any one of claims 8 to 16, further comprising continuously moving the pipe through the induction heater longitudinally to create a continuous 10 production process.

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