CN116670358A - Method for drying paper and technical textiles using inductive energy and associated paper machine dryer zone - Google Patents

Abstract

A paper machine has at least one dryer section or press section configured to receive a web of material, at least one inductive energy generator, and first and second fabrics, which may be dryer fabrics or press fabrics, including inductive heat receptors. The first and second fabrics are supported for movement through at least one of the dryer section or the press section and are adapted to contact the web of material. An inductive energy generator is used to generate heat in an inductive heat susceptor to heat a web carried by the fabric to remove moisture.

Description

Method and industrial use for drying paper using inductive energy and related paper machine dryer section textile

Cross References to Related Applications

This application asserts U.S. Provisional Application No. 63/107,807, filed October 30, 2020, U.S. Provisional Application No. 63/122,166, filed December 7, 2020, U.S. Provisional Application No. 63, filed February 22, 2021 /152,055 and priority of U.S. Provisional Application No. 63/193,671, filed May 27, 2021, the contents of which are incorporated herein by reference.

technical field

This invention relates to paper machines and more particularly to the dryer section.

Background technique

The dryer section of a paper machine typically uses a steam-heated dryer tank to dry the paper web conveyed through it. Steam heating is typical and requires a lot of thermal inertia (time to heat up and cool down). Drying costs are one of the most significant costs in papermaking, and drying consumes a lot of energy and has a great impact on the environment. A more economical, effective and environmentally friendly alternative to drying paper is desired.

Contents of the invention

In one aspect, the present invention relates to a paper machine, more particularly, usable in the dryer section or press section of a paper machine. For such applications, at least one of the dryer section or the pressurization section in the paper machine will be configured to receive a web of material and will include at least one inductive energy generator and at least one form of dryer fabric or pressurization fabric fabric, or a felt comprising inductive thermal receptors, wherein said at least one fabric is supported for movement throughout said dryer zone. The fabric may be a dryer fabric or a press fabric.

In connection with the use of the invention in the dryer section of a paper machine, there is provided at least a first dryer fabric comprising inductive thermoreceptors. In a preferred application, there is provided a first dryer fabric and a second dryer fabric, wherein the first dryer fabric is located adjacent to the second dryer fabric along at least a portion of the web path to define a web support space therebetween, Wherein the material web is adapted to be carried therein. At least one of the first dryer fabric and the second dryer fabric will include an inductive thermal sensor.

In one embodiment, the dryer fabric comprising the electro-thermosensor is a woven fabric comprising a plurality of filaments and at least a portion of the filaments comprise electro-thermo-responsive material. In another embodiment, the dryer fabric is a permeable nonwoven comprising an electrically conductive heat sensitive material. In further embodiments, the dryer fabric has an electro-thermosensitive coating.

In a preferred embodiment, said inductive energy generator is inductive thermal generation. In embodiments where there are two dryer fabrics running along the web path, both fabrics may be heated by the same inductive heat generating unit as inductive energy will pass through the web between the two fabrics. In alternative embodiments, the inductive energy generator may be a thermally insulated rotating roll, wherein the thermally insulated roll may be a ceramic roll or a thermoset polymer structure. The dryer zone may contain a plurality of inductive energy generators, which may be offset from each other. The plurality of inductive energy generators may be interleaved. Where the inductive energy generators are staggered across the machine direction of the dryer zone, when the amount of inductive heat transfer from each inductive heat generator can be adjusted, the inductive energy generators will allow Correction for cross-machine direction moisture distribution of the web. Furthermore, the inductive heat generating unit may be located, for example, in adjacent areas or between runs of the fabric, or in the area of a return run after the loaded paper has been transported to another area of the papermaking plant.

The dryer zone may include a dehumidification source. The dehumidification source can be a vacuum source, a roller source, a dryer, a mass transfer recovery source or an overpressure device. In embodiments where the dehumidification source is a vacuum source, the vacuum source may be a rotary vacuum or a stationary assembly vacuum. In a preferred embodiment, the vacuum source is a low vacuum unit - a box connected to a blower that creates negative air pressure to capture moist air evaporating from the web, using a low suction high capacity blower to create the vacuum. When the dehumidification source is a roller source, normal pressure rollers and low pressure rollers can be used for water replacement and recovery. When the dehumidification source is a mass transfer recovery source, water from the paper web is captured and reused in the papermaking process. When the dehumidification source is an overpressure device, the overpressure device may be a pressurized blower box, a pressurized roller or a fixed blower box. The dryer zone may include multiple dehumidification sources.

The dryer zone may include a transfer source. The source of transfer can be a vacuum box, suction nip roll or air duct which generates a concentrated air jet to reorient the web from the previous fabric. In a preferred embodiment, said transfer source is a vacuum box.

The dryer zone provides support for the movement of the dryer fabric. In one embodiment, the dryer fabric may be supported for movement by a plurality of rollers. In another embodiment, it may be supported by at least one vacuum source. In another embodiment, it may be supported by at least one fixed foil. In a further embodiment it may be supported by at least one rotating shroud moisture recovery unit.

In a preferred embodiment the dryer fabric in the dryer zone is supported by a plurality of rollers. The rollers may include at least one of main rollers, carrier rollers, guide rollers, or felt rollers. The main roll may include a driving roll or a stretching roll. In a preferred embodiment, there are four main rolls. In a further preferred embodiment, the four main rolls comprise two drive rolls and two draw rolls.

In a preferred embodiment said dryer zone comprises at least one guide roll for each dryer fabric.

In a preferred embodiment, the dryer zone comprises at least one load cell configured to measure the tension on the dryer fabric. Preferably, load sensors are included near the inlet and outlet of the dryer zone.

In an embodiment, said dryer zone comprises at least one rotating perforated vacuum roll. The rotating perforated vacuum roll is adjacent to at least one inductive energy generator.

A paper machine may include multiple dryer zones.

The invention also relates to an industrial textile, preferably a dryer fabric for a paper machine. The technical textile includes a fabric having first and second opposing surfaces, and an induction heating susceptibility material.

In one embodiment, said technical textile is woven. In an alternative embodiment, the technical textile is a penetrable nonwoven. In one embodiment, the technical textile comprises inductive heating susceptible filaments in at least one of the machine direction or the cross-machine direction. The inductively heating sensitive filaments may be metallic or a combination of metallic and polymeric materials, and are preferably conductive, magnetic, high thermal diffusivity materials, and may alternate with polymeric filaments within a weave pattern.

In another embodiment, the technical textile includes inductive heating receptive fibers formed from a polymer blended with an inductive heating receptive material. In further embodiments, the technical textile includes an induction heating sensitive coating. The coating may be on at least one of the first or second opposing surfaces. In other embodiments, the induction heating susceptibility material may contain at least one of graphite or magnetite.

The mass and/or contact surface area of the electro-receptive material is preferably optimized as it is more efficient to have greater mass and/or contact surface area, preferably a combination of both.

Preferably, said inductive heating sensitive filaments are arranged in said technical textile such that they are oriented at 90 degrees to the main current direction of the inductive heat generating coil.

The invention also relates to a method for drying a paper web in the dryer section of a paper machine. The method comprises receiving a paper web in a paper machine section, conveying the paper web along a transfer path through a paper machine dryer section into contact with a dryer fabric comprising an inductive heat sensor, and applying heat from at least one inductive heat generator. energy to heat the paper web, and the inductive heat generator activates the inductive thermal sensor to generate heat.

In a preferred embodiment, the inductive heat generator heats a dryer fabric comprising the inductive thermal susceptor which in turn heats the paper web.

A preferred method comprises providing a second dryer fabric comprising inductive thermoreceptors in a dryer zone of said paper machine, and conveying said web sandwiched between the dryer fabrics along said conveyance path, through At least a portion of a dryer section of the paper machine.

In one embodiment, the inductive heat generator comprises a plurality of inductive heat generators spaced along the transfer path, and the method further comprises activating the inductive heat sensor by applying the inductive heat from the plurality of inductive heat sensors. Generator energy is used to heat the paper web to generate heat to dry the paper web.

The method may also include removing moisture from the dryer zone by applying one of vacuum, rollers, dryers, or mass transport. Moisture removal from the dryer zone may be accomplished by applying a vacuum to the web at spaced intervals as the web moves along the transport path.

The resulting structure should provide a more economical, efficient and environmentally friendly paper machine dryer section. Compared with the existing steam heating technology, induction heating is a more efficient drying technology with lower driving power and consumption. The electricity used for induction heating is also more sustainable than the boilers currently used to generate steam for the dryer section of a conventional paper machine. Generating more tons per hour at a lower cost per ton can also increase production.

Additional benefits include reduced open draws, which is where the sheet breaks. A stronger web is also produced due to less stretching and pulling. Get faster set-up and heat-up due to the reduced time needed to thread the machine and activate heat-up. Inductive heating also offers the potential to reduce the dryer section footprint, and it is estimated that the dryer section of a conventional paper machine could be reduced to about half its current size, and possibly even to about four times its current size. one-third. No condensate management or complicated exhaust hoods are required.

On the other hand, the inductive thermal sensors can be considered as various components of the dryer section. In a preferred embodiment, said electrothermal sensor is a dryer drum. The dryer drum may include bearings around the outer diameter of the drum, the top drum is suspended from the machine frame and the bottom drum is supported by the frame. This external bearing arrangement allows retrofitting of existing dryer drums by removing the front and rear heads, providing dryers that are now true drums rather than steam pressurized vessels. The induction unit can be mounted across the entire inner surface of the drum to provide extremely efficient heating of the drum. Thanks to the significant weight reduction, it is now easy to feel the zone being driven. Vacuum dryer drums can also be retrofitted with a high vacuum unit inside the drum. Both retrofit dryer drums and retrofit vacuum dryer drums can be used in series. Applying this arrangement to just one or two cylinders provides comprehensive corrective control of even the most severe dryer moisture distribution problems.

In an alternative embodiment, the inductive thermal susceptor is a steel susceptor plate. The steel susceptor panel may be a barometric vented steel susceptor panel. It can be capped at both ends to create an air cushion to allow the sheet to travel over the susceptor plate.

With regard to the pressurized zone, the inductive heat generating unit may be the same as discussed above. The inductive heat generating unit can be located in the area of the material web or along the return run of the press felt.

The pressure fabric may be constructed in a similar manner as a dryer fabric with the electrothermal sensor in the woven fabric, at least a portion of the filaments in the base fabric comprising the electrothermal material, or a nonwoven fabric comprising the electrothermal material. Additionally, the electro-thermosensitive material may be provided in the batt fibers and/or the scrim needled into the base fabric.

Applicants' studies have shown that the heat transfer per unit area to be carried on the material web should be two or more times greater using an inductive energy generator than the standard heat transfer values seen with conventional dryer fabrics.

Description of drawings

The foregoing summary and the following detailed description will be better understood when read in conjunction with the accompanying drawings, which illustrate preferred embodiments of the invention. In the picture:

Fig. 1 is a schematic sectional view of a dryer section of a paper machine according to a first embodiment of the present invention.

Figure 2 is a schematic sectional view of the dryer section of a paper machine according to a second embodiment of the invention.

Fig. 3A is a schematic cross-sectional view of a dryer section of a paper machine according to a third embodiment of the present invention.

Figure 3B is a detailed view of a section of the dryer section of Figure 3A.

Fig. 4 is a schematic sectional view of a dryer section of a paper machine according to a fourth embodiment of the present invention.

Figure 4A is a schematic cross-sectional view of the dryer section of a paper machine with an inductive heat generating unit located along the run of the return fabric.

Figure 5 is a schematic sectional view of a section of the dryer section of a paper machine according to a fifth embodiment of the invention.

Figure 6 is a schematic cross-sectional view of a section of the dryer section of a paper machine according to a sixth embodiment of the invention.

Figure 7 is a schematic cross-sectional view of a section-to-section transfer of two dryer sections of a paper machine according to a first embodiment of the invention.

Figure 8 is a schematic cross-sectional view of a section-to-section transfer of two dryer sections of a paper machine according to a second embodiment of the invention.

Fig. 9A is a schematic cross-sectional view of a woven fabric with cross-machine direction filaments comprising an electrically conductive heat-sensitive material.

Figure 9B is a schematic cross-sectional view of a woven fabric having machine direction filaments comprising an electro-conductive heat-receptive material.

Figure 9C is a schematic cross-sectional view of a woven fabric having both machine direction and cross-machine direction filaments comprising an electro-thermosensitive material.

FIG. 9D is a schematic cross-sectional view of a woven fabric having machine direction filaments comprising an electrically conductive heat-sensitive material and cross-machine direction filaments comprising a combination of filaments comprising an electrically conductive heat-sensitive material and filaments not comprising an electrically conductive heat-sensitive material. .

9E is a schematic cross-sectional view of a braided fabric having cross-machine direction filaments comprising an electrically conductive thermally sensitive material and filler filaments comprising an electrically conductive thermally sensitive material (shown pivotally connected at two opposite ends of the fabric for illustrative purposes). Before).

Figure 9F is a cross-section through a metal filament.

Figure 9G is a cross-section through a metal filament with a polymeric coating.

Figure 10 is a plan view of a section of a permeable nonwoven comprising an electrically conductive heat sensitive material.

FIG. 11A is a schematic cross-sectional view of a woven fabric having an upper surface coated with a coating comprising an electroconductive thermosensitive material.

Figure 1 IB is a schematic cross-sectional view of a woven fabric with a lower surface applied with a coating comprising an electro-sensitive thermosensitive material.

Fig. 11C is a schematic cross-sectional view of a woven fabric with upper and lower surfaces coated with an electroconductive thermosensitive material.

Figure 12A is a schematic cross-sectional view of a metallic filament.

Figure 12B is a schematic cross-sectional view of a filament comprising metallic and polymeric materials.

Figure 13 is a flow chart outlining a method of drying a web of material.

14 is a plan view showing a first step in the formation of an induction coil according to one embodiment for an induction heat generating unit.

Figure 15 is a view of the induction coil of Figure 14 after a second step in which the induction coil is bent in an intermediate position so that the two parts of the coil face each other and define a gap therebetween for the web path.

Fig. 16 is a top view of the inductance coil shown in Fig. 15 .

Figure 17 is a plan view of an exemplary dryer fabric.

18 is a top view showing the exemplary dryer fabric of FIG. 17 passing through the induction coil of FIGS. 15 and 16 .

Figure 19 is a schematic cross-sectional view of the dryer section of a paper machine of an embodiment similar to that of Figure 1 using an inductive heat generating unit with the induction coils of Figures 15 and 16 .

Figure 20 is a top view of an alternative arrangement of induction coils formed as individual pancake coils arranged flat facing the fabric and spaced apart in the cross-machine direction of the dryer fabric.

FIG. 21 is a side view of the arrangement of FIG. 20 .

Figure 22 is a schematic perspective view of another alternative arrangement of an induction coil formed as a single cross-machine direction coil extending across the dryer fabric.

Figure 23 is a schematic perspective view of the arrangement of Figure 22, looking more directly at the side of the induction coil and one edge of the dryer fabric.

Figure 24 is a schematic cross-sectional view of a dryer section of a paper machine arranged with the induction coil arrangement of Figure 20 or 22 along the path of the dryer fabric(s) according to another embodiment.

Figure 25 is a top view of an alternative arrangement of induction coils formed as individual pancake coils arranged planar to the fabric and spaced apart in the machine direction of the dryer fabric.

Figure 26 is a side view of the arrangement of Figure 25 .

Figure 27 is a schematic perspective view of another alternative arrangement of an induction coil formed as a single coil extending in the machine direction of the dryer fabric.

Figure 28 is a schematic perspective view of the arrangement of Figure 27, looking more directly from the side at the induction coil and the dryer fabric extending through its aligned central opening.

Figure 29 is a schematic cross-sectional view of a dryer section of a paper machine according to another embodiment with the induction coil arrangement of Figure 25 or 27 arranged along the path of the dryer fabric(s).

Figure 30 is a plan view of an alternative embodiment of an induction coil for an inductive heat generating unit.

Fig. 31 is a plan view of another embodiment of an induction coil in the form of a pancake coil for an induction heat generating unit.

Fig. 32 is a schematic sectional view of the dryer section of the paper machine according to the first embodiment of the present invention.

Figure 33A is a schematic cross-sectional side view through a dryer drum having a solid shell.

Figure 33B is an end view of the dryer drum of Figure 33A.

Figure 33C is a schematic side elevation view of a dryer drum with a drilled or perforated shell.

Figure 33D is an end view of the dryer drum of Figure 33C.

Fig. 34 is a schematic sectional view of a dryer section of a paper machine according to a second embodiment of the present invention.

Figure 35 is a flowchart outlining a method of drying a web of material.

Figure 36 is a schematic illustration of a press zone of a paper machine according to one embodiment of the present invention.

Figure 37 is a cross-section through an exemplary press felt.

Detailed ways

Certain terms are used in the following description for convenience only and not limitation. The dryer section 10 according to the invention is a dryer section of a paper machine. Opposite sides of the fabric may represent first and second surfaces, top and bottom surfaces, or upper and lower surfaces of the fabric. Filaments are used to generally identify monofilament or multifilament fibers. The warp and weft yarns are used to select the filaments based on their vertically extending position in the fabric on the loom, which may be machine direction or cross-machine direction filaments in the fabric once installed on the paper machine. Machine direction and cross-machine direction filaments may include interwoven warp and weft filaments as well as intervening filaments extending in the machine direction or machine direction, including filler filaments at seams or other areas of the fabric.

In describing different embodiments, the same component numbers are used for components having the same function, even if there are minor differences in the specific components identified.

Referring to Figure 1, a first embodiment of a dryer zone 10 according to the invention will be described in more detail. The dryer zone 10 is configured to receive a material web 20 (paper web) along at least a portion of the web path of a web support space 22 defined by at least one dryer fabric 40 equipped with an inductive thermal sensor, and More preferably two dryer fabrics 40, 40' are defined. The dryer zone 10 has at least one inductive energy generator, shown here as an inductive heat generating unit 32 . The inductive heat generating unit 32 may be coiled, annealed, copper tube or litz wire, which generates an electromagnetic field when energized with electricity. An exemplary pancake coil 33 is shown in FIG. 31 , and each inductive heat generating unit 32 may have one or more such coils 33 . The coils may be encapsulated in thermoplastic or other suitable material to provide damage and/or wear protection. The inductive thermoreceptors of the dryer fabric 40, 40' capture the electromagnetic field and generate it via the Maxwell Lodge effect (Maxwell-

Lodge effect) generates heat from eddy currents. In a preferred embodiment, the susceptor will be oriented in a physical direction perpendicular to the current flow to maximize coupling to the electromagnetic field (EMF) generated by the inductive heat generating unit 32 . As the dryer fabrics 40 , 40 ′ transport the material web 20 through the dryer zone 10 they move supported by the main roll 80 , the carrier roll 86 and the felt roll 89 in this embodiment. The dryer zone may also include at least one dehumidification device, represented in this embodiment by a stationary vacuum box 60 . The vacuum box may be formed as one or more low vacuum units, a box connected to a blower that creates a negative air pressure to capture moist air evaporating from the web, said vacuum being established using a low suction high capacity blower. The dryer zone may also include at least one transfer source, represented in this embodiment by a transfer vacuum box 70 .

Referring to Figure 2, a second embodiment of a dryer zone 10' according to the invention is shown. The dryer zone 10 ′ is formed in a similar manner to the dryer zone 10 . This embodiment of the dryer section 10 ′ includes a plurality of drive rolls 82 and stretch rolls 84 . Guide rollers 88 configured to move to control fabric tension have been included within each of the dryer fabrics 40, 40'. A load cell 76 has also been included and is configured to measure the tension on the dryer fabric 40, 40'.

Referring to FIG. 3A, a third embodiment of a dryer zone 10" according to the present invention is shown. Similar in structure to dryer zones 10 and 10', this embodiment shows the replacement of drive roll 82 and stretch roll 84. Configuration and number. In this embodiment, additional carrier rollers 86 have been arranged outside each drive roller 82 near the edge of the dryer zone 10". Figure 3B shows a close-up view of a section of the drive roll 82 and corresponding carrier roll 86 to show the inner dryer fabric 40' wrapped around the drive roll 82 while the outer fabric separates and extends and wraps around the two carrier rolls 86 around. This configuration is to eliminate any speed mismatch effects on the material web 20 .

Referring to Figure 4, a fourth embodiment of a dryer zone 10"' according to the invention is shown. In this embodiment, the stationary vacuum box 60 of the dryer zone 10 is replaced by a rotary vacuum box 62, the rotary vacuum Box 62 may be contained within the perforated roll.

Figure 5 shows a section of the dryer section of a paper machine according to a fifth embodiment of the invention. In this embodiment, sections of the dryer zone alternate the inductive heat generating units 32 with the vacuum boxes 60 along the web path of the material web 20, with the inductive heat generating units 32 on the opposite side of the dryer fabrics 40, 40' located at Opposite the other inductive heat generating unit 32 and the vacuum box 60 on the opposite side of the dryer fabric 40 , 40 ′ is located opposite the other vacuum box 60 . A hot air scraper 78 is located adjacent to each vacuum box 60 .

Figure 6 shows a section of the dryer section of a paper machine according to a sixth embodiment of the invention. In this embodiment, sections of the dryer section alternate the inductive heat generating unit 32 with the vacuum box 60 along the web travel path of the material web 20, with the inductive heat generating unit 32 being located on the opposite side of the vacuum box from the drying fabric 40, 40' Opposite of , hot air scrapers 78 are also adjacent to each vacuum box 60 .

Figure 7 shows a section-to-section transfer of a material web 20 between two dryer zones 10a, 10b according to a first embodiment of the invention. Once the material web 20 has passed through the conveyor vacuum box 70 of the first dryer zone 10a, it will be fully supported and sandwiched between the dryer fabrics 40, 40' until it exits the section and passes into the next section, The next section is a similar section where the web path runs from top to bottom of the section instead of bottom to top.

Fig. 8 shows a section-to-section transfer of a material web between two dryer zones 10'a and 10'b according to a second embodiment of the invention, similar to Fig. 7 .

The inductive heat generating unit 32 in each of the embodiments described above may also be located in additional or alternative locations running along one or both of the dryer fabrics 40, 40'. For example, the inductive heat generating unit 32 may be provided on one or both return passes (after the separated regions above each other where the fabrics 40 , 40 ′ exit from the material web 20 ). See, eg, Figure 4A, where the inductive heat generating unit 32 is located on the return run of the dryer fabric 40'. Here, the inductive heat generating unit is located between and proximate to two sections of the dryer fabric 40'. The location of the inductive heat generating unit between the two sections of the dryer fabric is also shown in connection with Figures 24 and 29 below.

Referring to Figures 9A-E, a section of a woven fabric 42 forming part of a dryer fabric 40, 40' according to the present invention is shown. The finished dryer fabric may also include one or more needled batt materials attached to the woven fabric 42 . Woven fabric 42 includes opposing surfaces 50a and 50b and filaments 43, including machine direction (MD) filaments 44 and cross-machine direction filaments 45, woven together according to a repeating pattern. In FIG. 9A , the cross-machine direction (CD) filament 45a contains an inductive thermoreceptive material, while the machine direction filament 44b does not contain an inductive thermosensitive material as indicated by point 46 . The inductive thermal sensing material 46 is preferably a magnetic conductive material with high thermal diffusivity, and can be graphite, magnetite, carbon steel, galvanized steel, magnetic steel, various mixtures containing stainless steel, copper, aluminum or other conductive metals, Or a non-oxide ceramic material such as silicon carbide, which can be mixed with the polymer used to form the filament 45a in powder form. For example, 3-90wt% conductive material can be combined with polymers such as PPS, PEEK or PCTA with good high-temperature and high-humidity properties, or such as DuPont’s The non-melt processable aramid material is mixed and extruded to form filaments 45a. Those skilled in the art will recognize that other types of polymers can be used, as well as other electrothermosensitive materials.

Alternatively, the electro-thermosensitive material may be provided in the form of a metallic component woven into the fabric 42 in one or more MD or CD filament locations in the weave of the fabric, in place of the polymeric filaments or in addition to the polymeric filaments. outside of polymeric filaments. Such metal parts or strands are preferably in MD or CD, but may be more efficient in one direction based on coil design or orientation (i.e. when the coil is oriented in MD, the susceptor material in CD will be more efficient , and vice versa). The CD filaments 45a provided as metal strands provide better flexibility to the fabric 42 when combined with the polymeric MD filaments 44b. Metal CD strands 45a may be flat, round, or flattened round, such as metal strand 45a' shown in FIG. 9F. However, metallic MD strands 44a are also contemplated and may have a similar configuration. In a preferred embodiment, the metal MD strands 44a measure 2mm wide x 0.25mm thick (preferably with a flat cross section profile, with a minimum strand ratio of 2:1 to 8:1 for greater thermal contact area) .

Since metal-to-metal contact between components can lead to short circuits or hot spots, to avoid this problem a combination of metal and polymeric strands is preferred to prevent metal components from touching each other. Thus, this can be achieved by having metallic CD filaments 45a or metallic MD filaments 44a alternate preferably with polymeric CD filaments 45b or polymeric MD filaments 44b, respectively. Alternatively, for applications requiring a larger contact area of the susceptor material, where all metal strands are provided for MD strands 44a or CD strands 45a, if at least some of the metal strands are coated with a polymeric material, such as the coated filaments in FIG. 9G 45" section shown. This also provides additional protection should the strand break but stays with the polymeric coating.

Figure 9B provides an alternative embodiment of a woven fabric 42' in which the cross-machine direction filaments 45b do not contain an electrothermally sensitive material, while the machine direction filaments 44a contain an electrothermally sensitive material 46 and may be joined with materials such as those described above. Filaments 45a are formed. Here too, the machine direction filaments 44a containing the electrothermally sensitive material 46 may be interwoven or cabled to help prevent fatigue problems.

In FIG. 9C , another alternative embodiment provides a woven fabric 42 ″ in which both cross-machine direction filaments 45 a and machine direction filaments 44 a contain electrothermally sensitive material 46 .

In FIG. 9D, another embodiment provides a woven fabric 42"' in which both the machine direction filaments 44a and some of the cross-machine direction filaments 45a contain inductive heat-responsive material 46, while the other cross-machine direction filaments 45b contain no inductance. heat sensitive material.

In FIG. 9E, another embodiment of a woven fabric 42"" is shown. Similar to embodiment 42 in FIG. 9A, cross-machine direction filament 45a contains an inductive thermoreceptive material, as indicated by point 46, while machine direction filament 44b does not contain an inductive thermosensitive material. Additionally, a sewing loop 52 is shown at one end of the fabric 42"", while the opposite end would have similar sewing loops which could be crossed over each other and then connected with a pivot (not shown). Filler filaments 53 (one of which is shown in FIG. 9E for reference) are then inserted into the region of the attached sewing ring 52 outside the region occupied by the pivot. This preferably begins after the ends of the fabric 42"" are connected by a pivot. Here, the filling filament 53 also includes an inductive thermosensitive material 46 . While filler filaments 46 are shown at the seaming loops, such filaments including electrothermally sensitive material 46 may be inserted into other areas of the fabric, not only in the cross-machine direction, but also in the machine direction.

Referring to Figure 10, a permeable nonwoven 47 that may be used to form dryer fabrics 40, 40' in accordance with the present invention is shown. Penetrable nonwoven 47 includes opposing surfaces 50 a and 50 b and includes electro-thermosensitive material 46 . The penetrable nonwoven 47 may be at least one of a film, an extruded mesh, a composite or laminate with a penetrable layer, a foam, a non-crimped fabric with multiaxially oriented fibers, a knitted fabric, or a spiral fabric.

Referring to Figures 11A-C, a dryer fabric 40 according to the present invention is shown. Dryer fabric 40 includes opposing surfaces 50a and 50b and includes an electrically conductive heat-sensitive material coating 48 that includes electrically conductive heat-sensitive material 46'. In FIG. 11A, an inductive thermosensitive coating 48 has been applied to the upper surface 50a. In FIG. 11B, an inductive thermosensitive coating 48 has been applied to the lower surface 50b. In Figure 11C, an inductive thermosensitive coating 48 has been applied to two opposing surfaces 50a and 50b. Figures 11A-C provide a woven filamentary fabric 43, however an electro-thermosensitive coating 48 may also be applied to a non-woven fabric. Coating 48 may be a graphite pigment including a heat resistant binder. Coating 48 may alternatively include small iron particles such as magnetite and a conductive heat resistant binder in one dimension. Coating 48 may be applied to either or both sides of the finished dryer fabric 40 . Coating 48 may alternatively or additionally be applied to individual filaments 43 of woven fabric 42 prior to being woven.

Referring to Figures 12A and 12B, embodiments of filaments according to the present invention are shown. 12A provides a conductive filament 43' comprising an inductive heat sensing material 46", which may be made of, for example, graphite, magnetite, carbon steel, galvanized steel, various mixtures containing stainless steel, copper, aluminum, or other conductive metals, or Formed from a non-oxide ceramic material such as silicon carbide. Figure 12B provides a filament 43" formed as a multifilament or co-extruded as a single filament, which is a combination of a conductive electrothermosensitive material 46" and a polymeric material 49, Such as metals or ceramics mentioned above and polymers with good high temperature and high humidity properties, such as PPS, PEEK or PCTA, or non-melt processable aramids, such as DuPont's Material. The mixture must be electrically conductive and preferably magnetic.

Referring to Figure 13, a flow chart outlining the steps required to dry a web of material is provided. As represented by block 90, the first step involves receiving the paper web into the dryer section of the paper machine. A second step, provided in block 92, involves conveying the web along a conveyance path through a dryer zone of a paper machine into contact with a dryer fabric comprising an electrothermally sensitive material. Block 94 provides the final step of this embodiment of the invention and involves heating the web by applying energy from at least one inductive thermal generator that activates the inductive thermal sensing material to generate heat. Preferably, the inductive heat generator heats a dryer fabric comprising an inductive thermal susceptor that conducts heat to the web to dry the web.

In a preferred embodiment, the drying method involves providing a second dryer fabric comprising inductive thermoreceptors in a dryer zone of a paper machine, and conveying the paper web sandwiched between the dryer fabrics along a conveyance path through the papermaking At least a portion of the machine dryer zone. In another preferred embodiment, a plurality of inductive heat generators are provided spaced apart along the transport path, and the method further comprises heating the web by applying energy from said plurality of inductive heat generators, said energy activating Inductive thermal sensors to generate heat to dry the paper web. The method may further comprise removing moisture from the dryer zone by applying one of a vacuum, a roller, a dryer, or a mass transfer source, preferably by applying water to the web at spaced intervals as the web moves along the conveyance path. Apply vacuum to remove moisture from the desiccator zone. A preferred embodiment also involves forming a dryer fabric with inductive thermal receptors in or on the fabric.

14-16 show another embodiment of an inductive heating coil 34 for use in an inductive heat generating unit 32' that may be used in a dryer zone, such as that shown in FIG. 15 and 16 show the completed inductive heating coil 34 for use in the inductive heat generating unit 32 ′, and FIG. 14 shows the production steps for forming the inductive heat generating coil 34 . In FIG. 14, the inductive heat generating coil 34 is formed from annealed copper tube or other suitable material having a generally sinusoidal or other periodic curve and having a length L which is at least approximately Twice the width W of the dryer fabric 40, 40'. The inductive heat generating coil 34 is then bent in an intermediate position into the configuration shown in Figures 15 and 16 such that the two parts of said coil 34 face each other and define a gap 35 therebetween for the dryer fabrics 40, 40' Appropriate web path for travel.

An exemplary dryer fabric 40 is shown in FIG. 17 in which the weft yarns are metallic or otherwise incorporate an electrothermally sensitive material, and the warp yarns of polymeric material extend in the machine direction. FIG. 18 schematically shows a dryer fabric 40 extending through the gap 35 in the inductive heat generating coil 34 .

Figure 19 shows a dryer zone 10"" similar to the dryer zone 10 according to the first embodiment, which is configured to receive a material web 20 (paper web) along at least a part of the web path of the web support space 22, the web support The space 22 is defined by at least one dryer fabric 40 equipped with an inductive thermoreceptor, and more preferably by two dryer fabrics 40, 40'. The dryer zone 10"" has at least one inductive energy generator, shown here as an inductive heat generating unit 32' according to FIGS. 15 and 16. The inductive thermoreceptors of the dryer fabric 40, 40' capture the electromagnetic field and generate heat of eddy currents by the Maxwell-Lodge effect. As the dryer fabrics 40 , 40 ′ transport the material web 20 through the dryer zone 10 , they move supported by the main roll 80 , the carrier roll 86 and the felt roll 89 in this embodiment. The dryer zone 10"" may also include at least one dehumidification device, represented in this embodiment by a stationary vacuum box 60. The vacuum box may be formed as one or more low vacuum units comprising a box connected to a blower which creates a negative air pressure to capture humid air evaporated from the web, using a low suction high capacity blower to create the vacuum. Here, the recovered water vapor can be recycled back into the papermaking process. The dryer zone may also include at least one transfer source, represented in this embodiment by a transfer vacuum box 70 .

20 and 21 show another embodiment of an inductive heating coil 134 for an inductive heat generating unit 132 that may be used in a dryer zone, such as shown in FIG. 24 . 20 and 21 show the completed inductive heating coils 134 connected to the current sources of the inductive heat generating unit 132, respectively. The inductive heat generating coils 134 are preferably formed from annealed copper tubing or other suitable wafer-form material and are spaced apart in the cross-machine direction of the dryer fabric(s) 40, 40' from the dryer fabric Adjacent planes 40, 40' face each other but do not touch.

22 and 23 show another embodiment of an inductive heating coil 134' for an inductive heat generating unit 132' that may be used in a dryer zone, for example as shown in FIG. Figures 22 and 23 show the completed inductive heating coil 134' connected to the current source of the inductive heat generating unit 132'. The inductive heat generating coil 134' is preferably formed from annealed copper tubing or another suitable material as an elongated or flat single helical coil spanning the cross-machine direction of the dryer fabric 40, 40' with one side of the coil Towards and directly adjacent to, but not in contact with, the dryer fabrics 40, 40'.

Referring to Figure 24, another embodiment of a dryer zone 110 according to the present invention will be described in more detail. The dryer zone 110 is configured to receive a web of material 20 (paper web) along at least a portion of the web path of a web support space 22 defined by at least one dryer fabric 40 equipped with an inductive thermal sensor, and further Preferably defined by two dryer fabrics 40, 40'. The dryer section 110 has at least one inductive energy generator, shown here as an inductive heat generating unit 132 or 132'. The inductive heat generating unit 132, 132' is preferably as described above such that when powered with electricity an electromagnetic field is generated. The inductive thermoreceptors of the dryer fabric 40, 40' capture the electromagnetic field and generate heat from the eddy currents through the Maxwell-Loach effect. As the dryer fabrics 40 , 40 ′ convey the material web 20 through the dryer zone 110 , they are supported for movement by the main roll 80 , the carrier roll 86 and the felt roll 89 in this embodiment. The dryer zone 110 may also include at least one dehumidification device, such as the stationary vacuum box 60 described above. The dryer zone may also include at least one transfer source, such as the transfer vacuum box 70 discussed above.

FIGS. 25 and 26 show another embodiment of an inductive heating coil 144 for an inductive heat generating unit 142 that may be used in a dryer zone, for example as shown in FIG. 29 . 25 and 26 show the completed inductive heating coils 144 connected to the current sources of the inductive heat generating unit 142, respectively. The inductive heat generating coils 144 are preferably formed from annealed copper tubing or other suitable pancake-shaped material and are spaced apart in the machine direction plane adjacent to, but not in contact with, the dryer fabrics 40, 40'. As shown in Figure 29, the inductive heat generating units 142 may be positioned at various locations along the web path along which the dryer fabric(s) 40, 40' are adapted to travel. They may also be located along the return path of the dryer fabric(s) 40, 40'.

27 and 28 show another embodiment of an inductive heating coil 144' for an inductive heat generating unit 142' that may be used in a dryer zone, such as shown in FIG. Figures 27 and 28 show the completed inductive heating coil 144', connected to the current source of the inductive heat generating unit 142'. The inductive heat generating coil 144' is preferably formed from annealed copper tubing or another suitable material in an elongated or flat single helical coil having a central opening 146' defined through its center extending in the machine direction. The dryer fabrics 40 , 40 ′ extend in the machine direction through the central opening 146 ′ such that sections of the coil 144 ′ are adjacent but not in contact with both sides of the dryer fabrics 40 , 40 . As shown in Figure 29, the inductive heat generating units 142' may be arranged at various locations along the web path along which the dryer fabric 40, 40' is adapted to travel. They may also be positioned along the return path of the dryer fabrics 40, 40'.

Referring to Figure 29, another embodiment of a dryer zone 210 according to the present invention will be described in more detail. The dryer zone 210 is configured to receive a web of material 20 (paper web) along at least a portion of the web path of a web support space 22 defined by at least one dryer fabric 40 equipped with an inductive thermal sensor, and further Preferably bounded by two dryer fabrics 40, 40'. The dryer section 210 has at least one inductive energy generator, shown here as an inductive heat generating unit 142 or 142'. The inductive heat generating unit 142, 142' is preferably as described above such that when electrically charged an electromagnetic field is generated. The inductive thermoreceptors of the dryer fabric 40, 40' capture the electromagnetic field and generate heat from the eddy currents through the Maxwell-Loach effect. As the dryer fabrics 40, 40' convey the material web 20 through the dryer zone 210, they are supported for movement by the main roll 80, the carrier roll 86 and the felt roll 89 in this embodiment. The dryer zone 210 may further include at least one dehumidification device, such as the stationary vacuum box 60 described above. The dryer zone may also include at least one transfer source, such as the transfer vacuum box 70 discussed above.

Referring now to FIG. 30, another embodiment of an inductive heating coil 154 for an inductive heat generating unit that may be used in a dryer zone, such as any shown in the previous figures, is shown. The induction heating coil 154 is preferably formed from annealed copper tubing or another suitable material having a generally sinusoidal or other periodic curve extending across the dryer fabric 40, 40 adapted to be used therewith. 'Width W, and then extend back along a parallel path that is offset in the machine direction of the dryer fabric 40. Here, a dryer fabric is shown having cross machine direction yarns 45 made at least in part of an electrothermosensitive material.

Referring to Figure 32, another embodiment of a dryer section 310 is described. The dryer zone 310 is configured to receive the material web 20 (paper) along at least a portion of the web path of the web support space defined by at least one dryer fabric 340 (and more preferably two dryer fabrics 340, 340'). width). The dryer fabrics 340 , 340 ′ run around a series of dryer drums 334 and driven felt bag rolls 136 . The dryer zone 310 has at least one inductive energy generator, shown here as an inductive heat generating unit 332 , mounted across the inner surface of a dryer drum 334 . Bearings 312 are also provided which surround and rotatably support the outer radius of the drum. The top drum is suspended from the machine frame 314 and the bottom drum is supported by the frame 314 . The inductive heat generating unit 332 may be a coiled, annealed copper tube that generates an electromagnetic field when energized by electricity. The inductive thermal receptors are formed by the dryer drum 334 itself rather than in the dryer fabrics 340, 340'. They trap electromagnetic fields and generate heat from eddy currents through the Maxwell-Loach effect. The dryer zone may also include at least one dehumidification device, represented in this embodiment by vacuum box 60 , also located within dryer drum 334 .

Referring to Figures 33A-33D, various views of dryer drum 334 are provided. Figure 33A provides a schematic cross-sectional side view through a solid shell dryer drum 334 with an inductive heat generating unit 332 mounted across the width of the inner surface. The inductive heat generating unit 332 is fixed to the frame of the dryer zone by a steel frame 318 which is installed to the existing dryer zone frame and passed through the inductive heat generating unit 332 to the dryer drum thereon 334. A power and DCS control supply 319 is also provided. 33B is an end view of the dryer drum 334 of FIG. 33A , showing the inductive heat generating unit 332 within the dryer drum 334 , and the bearings 312 that provide rotatable support for the dryer drum 334 . One bearing 312 is preferably located at each end of the dryer drum 334 . Figure 33C provides a schematic side elevation view of a dryer drum 334' having a perforated or drilled outer shell 338 where moisture can be drawn through the vacuum box 60 located inside. Figure 33D is an end view of the dryer drum 334' of Figure 33C, showing the inductive heat generating unit 332 and vacuum box 360 within the dryer drum 334'. Bearings such as the bearings 312 described above will be located at each end of the dryer drum 334' to allow for rotation.

Referring to Figure 34, another embodiment of a dryer section 310' according to the present invention is shown. This embodiment of the dryer section 310' includes an inductive heat generating unit 332 and an inductive heat susceptor plate 336 on one side of the sheet run, while the other side of the sheet run has inductive heat generation alternating along the web path of the material web 20. unit 332 and vacuum box 360. The inductive thermal susceptor plate 336 is a steel plate positioned adjacent to the material web 20 and preferably includes a plurality of openings that can be connected to a vacuum source. The vacuum box can be formed as one or more low vacuum units, boxes connected to blowers that create negative air pressure to capture humid air evaporated from the web, using low suction high capacity blowers to create the vacuum.

Referring to Figure 35, a flow chart outlining the steps required to dry a web of material is provided. As represented by block 390, the first step involves receiving the web into the dryer section of the paper machine. A second step provided in block 392 involves conveying the web along a conveyance path through a dryer section of the paper machine proximate at least one inductive thermal susceptor. Block 394 provides the final step of this embodiment of the invention comprising heating the web by applying energy from at least one inductive heat generator that activates at least one inductive thermal sensor to generate heat. Preferably, the inductive heat generator heats at least one inductive thermal susceptor which conducts heat to the paper web to dry the paper web.

Referring to Figure 36, an exemplary pressurized zone 412 is shown. In use, the pressurization zone 412 is upstream of the dryer zone 10 . There is one or more press fabrics or felts 440, 440', 440", which carry the material web 20 from the forming zone through at least one nip formed between press rollers 484 in the press zone 412, so that the material web 20 20 to remove moisture. Press fabrics 440 , 440 ′, 440 ″ are carried on rollers 480 and driven by press rollers 484 . Tension rollers 488 are provided for tensioning the press fabrics 440, 440', 440". Here, as discussed above, the inductive heat generating unit 32 is located along the path of the press fabrics 440, 440', 440", and a One or more of the compression fabrics includes the electrothermally sensitive material in the base fabric and/or in the batting or scrim needle punched onto the base fabric. The inductive thermosensitive material may be incorporated as discussed above in connection with the dryer fabrics 40, 40'.

Referring to Fig. 37, an exemplary zone of a press felt 440 is shown. Here, the base fabric 442 is made of machine direction filaments 444a and cross-machine direction filaments 445a, similar to the filaments 44a, 45a discussed above, one or both of which may contain the electrothermally sensitive material 46. Additionally, one or more layers of batt fibers 449a, 449b are needle punched onto the base fabric 442, and the batt fibers 449 may also include electro-thermosensitive materials of the type discussed above. Although a woven base fabric 442 is shown, a non-woven base fabric may also be used.

In addition to compressing the material web 20 via the press nip and mechanical moisture removal via suction boxes that may be located along the path of the web 20, the additional heat in the press zone 412 also aids in the removal of moisture from the material web.

The above-described embodiments of the dryer zone and press zone, technical textiles and methods of drying paper are considered to be exemplary.

While the preferred embodiment has been described primarily in connection with the dryer section 10 or press section 412 of a paper machine, other applications where this technology may be applied include: other areas of the dryer section of a paper machine, as well as single pass, sizing presses , during or after coating; pressurized felt with susceptor material and induction coil, used with or instead of a steam box to heat the wet sheet as it passes through the vacuum box, and/or through the nip materials; technical textiles with susceptor materials used in the forming zone of paper machines for induction coils to heat wires for localized heat input to reduce viscosity for drainage; induction coils between pressurized and dryer zones; Technical Textiles with Sensitive Material for Pulp Machine Applications; Pressed Felt with Inductive Sensitive Material in Bat Fibers; Pressed Felt with Inductive Sensitive Web Embedded Near Paper Surface; For Extended Nip Pressing (ENP ) for technical textiles with sensory materials; and various other papermaking applications.

Having thus described the invention in detail, it is to be understood and will be apparent to those skilled in the art that numerous substantial changes may be made without altering the inventive concepts and principles embodied therein, only a few of which are in the present invention Examples are given in the detailed description. It should also be understood that many embodiments are possible incorporating only parts of the preferred embodiment, with respect to those parts, without altering the inventive concepts and principles embodied therein. Accordingly, the present embodiments and alternative configurations are to be considered in all respects as exemplary and/or illustrative and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description and all alternative embodiments and references Variations thereto are indicated, therefore, embodiments which come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Claims (25)

1. A paper machine, comprising: at least one of a dryer or a pressurized zone configured to receive a web of material, at least one inductive energy generator, and First and second fabrics comprising inductive thermal receptors, the first and second fabrics are supported for movement through at least one of the dryer zone or the pressurization zone and are adapted to contact the material web. 2. The papermaking machine of claim 1, wherein said first fabric is located adjacent said second fabric along at least a portion of the web path to define a web support space therebetween, said web of material being adapted to is carried in it. 3. The paper machine of claim 1, wherein at least one of said fabrics comprising said electro-thermoreceptors is a woven fabric comprising a plurality of filaments, wherein at least a portion of said filaments comprise electro-thermo-responsive material . 4. The paper machine of claim 1, wherein at least one of the fabrics including the electro-thermosensor is a permeable non-woven fabric including an electro-thermo-responsive material. 5. The paper machine of claim 1, wherein at least one of the fabrics comprising the susceptor is a fabric comprising an electro-thermosensitive coating. 6. The paper machine of claim 1, wherein the at least one inductive energy generator is selected from at least one of an inductive heat generating unit or a thermally insulated rotating roll. 7. The paper machine according to claim 6, wherein said at least one inductive energy generator is an inductive heat generating unit. 8. The papermaking machine of claim 7, wherein the inductive heat generating unit comprises an inductive heating coil having an opening defined therethrough, and the fabric is adapted to travel The web path extends through the opening. 9. The paper machine of claim 7, wherein said inductive heat generating unit comprises an inductive heating coil located adjacent said first and said second fabrics. 10. The papermaking machine of claim 1, wherein said at least one inductive energy generator comprises a plurality of inductive energy generators. 11. The papermaking machine of claim 10, wherein said plurality of inductive energy generators are mutually biased. 12. The paper machine of claim 10, wherein the plurality of inductive energy generators are interleaved. 13. The papermaking machine of claim 1, wherein at least one of the dryer zone or the press zone comprises a plurality of dryer zones. 14. An industrial textile comprising a fabric having first and second opposing surfaces, and an induction heating susceptibility material. 15. The technical textile according to claim 14, wherein the technical textile is a dryer fabric or a press fabric for a paper machine. 16. The technical textile according to claim 14, wherein the technical textile is woven or penetrable non-woven. 17. The industrial textile according to claim 14, wherein the induction heating sensitive material is selected from at least one of induction heating sensitive filaments or induction heating sensitive fibers. 18. The technical textile according to claim 17, wherein the filaments are formed from an electrically conductive material. 19. The technical textile according to claim 17, wherein the filaments are a combination of conductive and polymeric materials. 20. The technical textile according to claim 14, wherein said inductively heating sensitive material is a coating on at least one of said first or said second opposing surfaces. 21. The technical textile of claim 14, wherein the inductively heating sensitive material comprises at least one of graphite, carbon steel, galvanized steel, stainless steel, copper, aluminum, silicon carbide, or magnetite. 22. A method of drying a paper web comprising: a paper web received in a paper machine zone, preferably at least one of a dryer zone or a press zone; conveying the web along a conveyance path through a zone of the paper machine in contact with a fabric comprising an inductive thermoreceptor, and heating the web by applying energy from at least one inductive heat generator that activates the inductive thermal susceptors to generate heat; Wherein the inductive heat generator generates heat in the fabric comprising inductive thermal susceptors that heat the web. 23. The method of claim 22, further comprising: In said paper machine zone, providing a second fabric comprising inductive thermoreceptors; and Along the transport path, the paper web, sandwiched between the fabrics, is transported through at least a part of the paper machine section. 24. The method of claim 22, wherein the at least one inductive heat generator comprises a plurality of inductive heat generators spaced along the transfer path, and the method further comprises activating the inductive heat generator by applying The energy of the plurality of inductive heat generators of the susceptor is used to generate heat to heat the paper web to dry the paper web. 25. The method of claim 22, further comprising: The fabric having inductive thermal receptors is formed in or on the fabric.