Knitted heater and method of manufacture

Abstract

A cloth heater is formed by a three-dimensional (3D) knitting machine. The cloth heater includes an outer layer, an inner layer, and a carrier layer disposed between the inner layer and the outer layer. The carrier layer includes a carrier substrate and a resistive heating element sewn to the carrier substrate in a pattern by the 3D knitting machine. An insulation layer is disposed between the outer layer and the carrier layer, and the outer layer and the inner carrier layer are formed by the 3D knitting machine.

Description

Attorney Docket No.: 0100H-000554-WO-POAKNITTED HEATER AND METHOD OF MANUFACTURECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Patent Application No. 63 / 692,417, filed on September 9, 2024. The disclosure of the above application is incorporated herein by reference in its entirety.FIELD

[0002] The present disclosure relates to cloth heaters for use in heating fluid conduits, and more specifically to cloth heaters formed using three-dimensional knitting technologies.BACKGROUND

[0003] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0004] Cloth heaters are often used for heating fluid conduits, an application in which the cloth heaters are cylindrical in shape and are wrapped around the outside of the fluid conduits. Cloth heaters generally include a resistive heating element that is sandwiched between an inner and outer layer of cloth material, with an optional layer of insulation disposed between the resistive heating element and the outer cloth layer. The resistive heating element defines a trace, or pattern, which delivers a predetermined amount of heat according to application requirements.

[0005] During manufacture of the cloth heater, the resistive heating element is manually located along the inner cloth layer and "tacked" or secured in specified locations in order to create and maintain the shape of the trace, or pattern. Such tacking is typically accomplished with yarn or threads in a stitching operation, which is a labor intensive process with relatively large process tolerances, or nonuniformities. As a result, the resistive heating element varies from its nominal trace geometry, which may negatively impact heater performance and / or reliability.

[0006] These challenges associated with the manufacture of cloth heaters and their application to fluid conduits are addressed by the present disclosure.SUMMARY

[0007] This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features.

[0008] In one form, a cloth heater is formed by a three-dimensional (3D)Attorney Docket No.: 0100H-000554-WO-POA knitting machine, the cloth heater comprising an outer layer, an inner layer, and a carrier layer disposed between the inner layer and the outer layer. The carrier layer comprises a carrier substrate and a resistive heating element sewn to the carrier substrate in a pattern by the 3D knitting machine. An insulation layer is disposed between the outer layer and the carrier layer, and at least the outer layer and the inner carrier layer are formed by the 3D knitting machine.

[0009] In variations of this cloth heater, which may be implemented individually or in any combination: the insulation layer is formed by the 3D knitting machine with the outer layer and the inner layer; the outer layer and the inner layer are configured by the 3D knitting machine to form a pocket, the pocket configured to receive the insulation layer; each of the outer layer, inner layer, carrier layer, and insulation layer are formed simultaneously in a single process; a plurality of carrier substrates and a corresponding plurality of resistive heating elements are sewn to the plurality of carrier substrates, wherein the plurality of carrier substrates and plurality of resistive heating elements are arranged in zones along a length of the cloth heater; at least one sensor is secured to a portion of the cloth heater; the at least one sensor is a temperature sensor; and power leads are operatively secured to respective end portions of the resistive heating element.

[0010] In another form of the present disclosure, a method of forming a cloth heater formed by a three-dimensional (3D) knitting machine is provided. The method comprises simultaneously forming an outer layer, an inner layer, a carrier layer between the inner layer and the outer layer, the carrier layer comprising a carrier substrate and a resistive heating element sewn to the carrier substrate in a pattern by the 3D knitting machine, and an insulation layer.

[0011] In another form of the present disclosure, a method comprises forming a cloth heater by forming an inner layer and an outer layer with a pocket therebetween, inserting an insulation layer between the inner layer and the outer layer, and securing a carrier layer between the insulation layer and the inner layer, the carrier layer comprising a carrier substrate and a resistive heating element sewn to the carrier substrate in a pattern. In a variation of this method, the resistive heating element is sewn to the carrier substrate by a 3D knitting machine.

[0012] Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit theAttorney Docket No.: 0100H-000554-WO-POA scope of the present disclosure.DRAWINGS

[0013] In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

[0014] FIG. 1A is a perspective view of a cloth heater for a fluid conduit heating application according to the teachings of the present disclosure;

[0015] FIG. 1 B is a perspective cutaway view of the cloth heater of FIG. 1A showing different layers of the cloth heater according to the teachings of the present disclosure;

[0016] FIG. 1C is a schematic cross-sectional view of a portion of the cloth heater of FIGS. 1 A and 1 B;

[0017] FIG. 2 is a schematic view of a cloth heater being manufactured with an automated 3D knitting machine according to the teachings of the present disclosure;

[0018] FIG. 3 is a plan view of a portion of a cloth heater with a resistive heating element defining a trace / pattern in accordance with the teachings of the present disclosure;

[0019] FIG. 4 is a perspective view of one form of a cloth heater having an interchangeable insulation layer constructed in accordance with the teachings of the present disclosure;

[0020] FIG. 5 is a perspective view of one form of a portion of a cloth heater having an outer layer and an inner layer constructed in accordance with the teachings of the present disclosure;

[0021] FIG. 6 is an exploded perspective view of another form of a cloth heater having a resistive heating element knit to a carrier layer and constructed in accordance with the teachings of the present disclosure; and

[0022] FIG. 7 is a perspective view of various geometries that may be formed for cloth heaters constructed in accordance with the teachings of the present disclosure.

[0023] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.Attorney Docket No.: 0100H-000554-WO-POADETAILED DESCRIPTION

[0024] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0025] Referring to FIGS 1A - 1C, the construction of an exemplary cloth heater 100 for use in heating fluid conduits is illustrated. The cloth heater 100 is generally cylindrical in shape and configured to wrap around a fluid conduit 10. The fluid conduit 10 may carry any form of fluid, including gas, liquid, or plasma. In one form, the fluid conduit 10 carries gas for pump lines, fore lines, and / or exhaust lines in a semiconductor manufacturing process. It should be understood, however, that the cloth heater 100 as disclosed herein may take on any number of geometries other than cylindrical and may be used for other applications besides semiconductor manufacturing while remaining within the scope of the present disclosure.

[0026] As shown, the cloth heater 100 includes an outer layer 102, an inner layer 104 disposed proximate the fluid conduit 10, a carrier layer 106 disposed between the inner layer 104 and the outer layer 102, and an insulation layer 108 disposed between the outer layer 102 and the carrier layer 106. The carrier layer 106 is disposed proximate the inner layer 104 and includes a carrier substrate 110 and a resistive heating element 112 secured to the carrier substrate 110. As further shown, a pair of lead wires 114 are in electrical communication with end portions (not shown) of the resistive heating element 112 to provide power to the resistive heating element 112. The lead wires 114 may also include connectors 116 to further connect the lead wires 114 to either another set of lead wires 114, a controller (not shown), or other electrical component.

[0027] The outer layer 102 and the inner layer 104 are formed from an electrically insulating material, such as by way of example, a PTFE (Polytetrafluoroethylene) coated fiberglass and function to protect the environment / adjacent components from the electrically live carrier layer 106. As set forth in greater detail below, both the outer layer 102 and the inner layer 104 are in a cloth (also referred to as a "textile") form and are manufactured using an automated three-dimensional (3D) knitting machine. It should be understood that materials other than PTFE coated fiberglass may be employed while remaining within the scope of the present disclosure. For example, other materials that may be used for the outerAttorney Docket No.: 0100H-000554-WO-POA layer 102 and / or the inner layer 104 include silica glass, alumina glass, and basalt glass, and aramid fibers, with or without a polymer coating such as PTFE.

[0028] The carrier layer 106 is disposed proximate the inner layer 104 so that the resistive heating element 112 is closer to and can provide heat more effectively to the fluid conduit 10. The carrier substrate 110 is also a textile material, such as by way of example, fiberglass, silica glass, alumina glass, basalt glass, and aramid fibers, with or without a polymer coating such as PTFE. The resistive heating element 112 is an electrically conductive wire, such as by way of example, a nickel alloy wire. The resistive heating element 112 is sewn into the carrier substrate 110 by any number of methods, including the automated 3D knitting machine, as set forth in greater detail below. Further, in one form, the carrier substate 110 and the resistive heating element 112 are manufacturing using an automated three-dimensional (3D) knitting machine, which is described in greater detail below.

[0029] The insulation layer 108 is generally a thermally insulating material such as fiberglass, silica glass, alumina glass, and basalt glass, with or without a polymer coating such as PTFE, and various ceramic fibers, and functions to insulate the fluid conduit 10 and the resistive heating element 112 from an outside environment, thereby providing more efficient heat transfer from the resistive heating element 112 to the fluid conduit 10. In one form of the present disclosure, the insulation layer 108 is formed using an automated three-dimensional (3D) knitting machine as set forth in greater detail below. In another form, the insulation layer 108 is an aerogel material.

[0030] Referring specifically to FIG. 1 B, in one form of the present disclosure, one or more sensors 120, such as by way of example a temperature sensor, is secured within the cloth heater 100 in order to provide process data (e.g., temperature) during operation of the cloth heater 100. In another form, the material of the resistive heating element 112 may have a temperature coefficient of resistance (TOR) high enough such that the heater functions as a heater and a temperature sensor, thereby eliminating the need for discrete temperature sensors 120. Further, other types of sensors, such as by way of example, gas sensors, vibration sensors, and RFID (Radio Frequency Identification) sensors, among others, may be employed within or on the cloth heater 100 while remaining within the scope of the present disclosure.Attorney Docket No.: 0100H-000554-WO-POA

[0031] As further shown, the cloth heater 100 in one form includes hook and loop fasteners 130 extending along edges 132, which are used to secure the cloth heater 100 around the fluid conduit 10, or other heating target. With the various layers and their respective materials, i.e., textiles, the cloth heater 100 is relatively flexible and can be wrapped around complex shapes such as the fluid conduit 10, among other shapes as set forth below.

[0032] Referring to FIG. 2, one or more of the layers of the cloth heater 100 are formed using an automated knitting machine 200, such as by way of example, TT machines provided by H. Stoll AG & Co. In one form, the automated knitting machine 200 is an automated flat v-bed knitting machine.

[0033] Referring to FIG. 3, the 3D knitting machine 200 in one form is employed to manufacture the carrier layer 106, and more specifically the carrier substrate 110 and the resistive heating element 112 together. The 3D knitting machine 200 winds the resistive heating element 112 in a pattern (or trace) as shown, at the same time with the carrier substrate 110 to form the carrier layer 106 in a single process. The carrier substrate 100 is made up of a plurality of yarns as shown, which may be arranged in warp and / or weft directions (not shown) as a function of application requirements and capabilities of the 3D knitting machine 200.

[0034] Referring now to FIG. 4, in one form, the 3D knitting machine 200 is used to form both the outer layer 102 and the inner layer 104 together and a pocket 140 therebetween as shown. The pocket 140 is configured to receive the insulation layer 108, which may be formed with the 3D knitting machine 200 or by another method, depending on the material of the insulation layer 108. For example, if the insulation layer 108 is an aerogel material, the insulation layer 108 is preformed in a shape that can easily be inserted into the pocket 140. The insulation layer 108 would then be secured between the outer layer 102 and the inner layer 104 using, by way of example, stitching. (The carrier layer 106 is not shown for purposes of clarity).

[0035] Turning to FIG. 5, the 3D knitting machine 200 is used to form both the outer layer 102 and the inner layer 104 together in a single process. The carrier layer 106 may also be formed in the same single process with the outer layer 102 and the inner layer 104, or the carrier layer 106 may formed separately (using the 3D knitting machine 200 or other) and secured to the inner layer 104 using a separate process as set forth in greater detail below. The 3D knitting machine 200 may also beAttorney Docket No.: 0100H-000554-WO-POA employed to form each of the outer layer 102, the inner layer 104, the carrier layer 106, and the insulation layer 108 simultaneously in a single process.

[0036] Referring to FIG. 6, the 3D knitting machine 200 is used to form both the outer layer 102 and the inner layer 104 together in a single process, while the carrier layer 106 is formed separately (using, for example, the 3D knitting machine 200). In a variation of this form, the carrier layer 106, or multiple carrier layers 106, having different arrangements of resistive heating elements 112 having corresponding different watt densities can be arranged between the outer layer 102 and the inner layer 104 along the length of the cloth heater 100. Accordingly, a plurality of resistive heating elements 112 are sewn to a corresponding plurality of carrier substrates 110, wherein the plurality of carrier substrates 110 and plurality of resistive heating elements 112 may be arranged in zones along a length of the cloth heater 100. As a result, the cloth heater 100 in this form has a variable watt density along its length with the use of interchangeable segments of carrier substrates 100 and resistive heating elements 112.

[0037] As shown in FIG. 7, a number of different geometries of the cloth heater 100 may be manufactured using the 3D knitting machine 200. It should be understood that these geometries are merely exemplary and should not be construed as limiting the scope of the present disclosure.

[0038] The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. For example, in one form of the cloth heater 100, the carrier layer 106 may be eliminated and the resistive heating element 112 is sewn / secured directly to the inner layer 104. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.

[0039] Unless otherwise expressly indicated herein, all numerical values indicating mechanical / thermal properties, compositional percentages, dimensions and / or tolerances, or other characteristics are to be understood as modified by the word “about” or "approximately" in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice, material, manufacturing, and assembly tolerances, and testing capability.

[0040] As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, andAttorney Docket No.: 0100H-000554-WO-POA should not be construed to mean “at least one of A, at least one of B, and at least one of C.”

Claims

Attorney Docket No.: 0100H-000554-WO-POACLAIMSWhat is claimed is:1 . A cloth heater formed by a three-dimensional (3D) knitting machine, the cloth heater comprising: an outer layer; an inner layer; a carrier layer disposed between the inner layer and the outer layer, the carrier layer comprising a carrier substrate and a resistive heating element sewn to the carrier substrate in a pattern by the 3D knitting machine; and an insulation layer disposed between the outer layer and the carrier layer, wherein the outer layer and the inner carrier layer are formed by the 3D knitting machine.

2. The cloth heater according to claim 1 , wherein the insulation layer is formed by the 3D knitting machine with the outer layer and the inner layer.

3. The cloth heater according to claim 1 , wherein the outer layer and the inner layer are configured by the 3D knitting machine to form a pocket, the pocket configured to receive the insulation layer.

4. The cloth heater according to claim 1 , wherein each of the outer layer, inner layer, carrier layer, and insulation layer are formed simultaneously in a single process.

5. The cloth heater according to claim 1 , further comprising a plurality of carrier substrates and a corresponding plurality of resistive heating elements sewn to the plurality of carrier substrates, wherein the plurality of carrier substrates and plurality of resistive heating elements are arranged in zones along a length of the cloth heater.

6. The cloth heater according to claim 1 , further comprising at least one sensor secured to a portion of the cloth heater.Attorney Docket No.: 0100H-000554-WO-POA7. The cloth heater according to claim 6, wherein the at least one sensor is a temperature sensor.

8. The cloth heater according to claim 1 , further comprising power leads operatively secured to respective end portions of the resistive heating element.

9. A method of forming a cloth heater formed by a three-dimensional (3D) knitting machine, the method comprising simultaneously forming an outer layer, an inner layer, a carrier layer between the inner layer and the outer layer, the carrier layer comprising a carrier substrate and a resistive heating element sewn to the carrier substrate in a pattern by the 3D knitting machine, and an insulation layer.

10. A method of forming a cloth heater, the method comprising: forming an inner layer and an outer layer with a pocket therebetween; inserting an insulation layer between the inner layer and the outer layer; and securing a carrier layer between the insulation layer and the inner layer, the carrier layer comprising a carrier substrate and a resistive heating element sewn to the carrier substrate in a pattern.11 . The method according to claim 10, wherein the resistive heating element is sewn to the carrier substrate by a 3D knitting machine.

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