US20060144563A1 - Plasmatized heat exchanger - Google Patents

Plasmatized heat exchanger Download PDF

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Publication number
US20060144563A1
US20060144563A1 US10/544,603 US54460305A US2006144563A1 US 20060144563 A1 US20060144563 A1 US 20060144563A1 US 54460305 A US54460305 A US 54460305A US 2006144563 A1 US2006144563 A1 US 2006144563A1
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US
United States
Prior art keywords
heat exchanger
plasma
exchanger according
treated
heat
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US10/544,603
Inventor
Ludwig Hellenthal
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Walzen Irle GmbH
Original Assignee
Walzen Irle GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Walzen Irle GmbH filed Critical Walzen Irle GmbH
Assigned to WALZEN IRLE GMBH reassignment WALZEN IRLE GMBH ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HELLENTHAL, LUDWIG
Publication of US20060144563A1 publication Critical patent/US20060144563A1/en
Abandoned legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F5/00—Elements specially adapted for movement
    • F28F5/02—Rotary drums or rollers
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
    • D21G1/00—Calenders; Smoothing apparatus
    • D21G1/02—Rolls; Their bearings
    • D21G1/0246—Hard rolls
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F19/00—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers
    • F28F19/02—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers by using coatings, e.g. vitreous or enamel coatings
    • F28F19/06—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers by using coatings, e.g. vitreous or enamel coatings of metal

Definitions

  • the invention pertains to a heat exchanger according to the introductory clause of claim 1 .
  • These types of heat exchangers are used in the production or finishing of web-like products in the industry, primarily in calenders.
  • the heat-transfer outputs and surface temperatures required in the new multi-nip calender rolls subject the conventional calender roll materials such as white cast iron, spheroidal graphite iron, and chromium alloy cast iron to loads which exceed their capacity.
  • Forged steel is currently the material which is able to fulfill these requirements. Because adequate forged steel can be hardened and tempered only up to 400-450 HV without sacrificing the advantages of forged steel, the surfaces of these rolls are coated either by electrocoating or by a thermal coating process or they are case-hardened by inductive hardening or flame hardening.
  • Thermally applied surface coatings suffer not only from insufficient reliability but also from the disadvantage of the relatively high porosity of the finished layer. Wear particles are able to penetrate into these pores and into the softer matrix regions and to wash them out. Case-hardened forged steel rolls suffer not only from inadequate tempering properties and the associated lack of sufficient hardness but also from an unfavorable internal stress distribution, caused by the case-hardening process. High tensile stresses in the area of the zone affected by the hardening process destroy the advantages of the good mechanical properties of forged steel.
  • New coating compounds and feed materials being used in papermaking call for increased chemical and mechanical corrosion resistance not only of the barrel of the roll but also of the entire surface exposed to the environment and to the product web. Because of the enormous heat-transfer outputs (>80 kW/m) and the continually increasing heat-transfer temperatures, the contact surfaces exposed to the fluid heat transfer media are subject to ever greater chemical/mechanical corrosion.
  • the invention is based on the task of improving the heat exchanger of the general type in question in such a way that it no longer suffers from the disadvantages mentioned above, especially so that surface hardnesses of considerably more than 400-450 HV are reached, and so that chemical/mechanical corrosion is minimized even at heat-transfer outputs of >80 kW/m.
  • the previously described hardened and tempered forged steel rolls are plasma-treated in the desired areas.
  • the term “plasma-treating” is used in the following as a collective term for “plasma nitriding”, “plasma nitrocarburizing”, “plasma oxidizing”, “plasma carbonitriding”, and “plasma carborizing”. This operation is usually carried out in a vacuum chamber at treatment pressures of 0.3-10 mbars.
  • the treatment temperature is in the range of 400-600° C., depending on the task to be accomplished.
  • Ammonia, nitrogen, methane, and hydrogen are usually used as the process gases.
  • Pressure, temperature, time, and gas type are the parameters used to vary the nature of the layers and the desired surface hardnesses.
  • Hardnesses of up to 1200 HV can be reached on the desired surfaces, and a hardening depth of up to 1 mm is realized. In addition to this extreme hardness, these diffusion layers do not produce any increase in the porosity which could be damaging to the wear process. The porosity of the substrate remains intact. In addition, the resistance to chemical corrosion is enormously improved.
  • Subsurface corrosion known from thermal spray coatings or even hard chromium-alloy coatings, is not possible when plasma-treating is used.
  • the bonding layer with the surface passivates the surface against oxidative attach.
  • Microcracks also known from the processes mentioned above, do not develop either.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Coating By Spraying Or Casting (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
  • Paper (AREA)

Abstract

The invention relates to a temperature-controlled, rotating, rotational symmetric heat exchanger, particularly for the pressing mechanism, drying mechanism or smoothing mechanism of a machine for producing web-like products such as paper webs or plastic films. The heat exchanger can be temperature-controlled preferably with fluids or vaporous heat transfer media or with heating involving electrical means. The aim of the invention is to improve a heat exchanger of the aforementioned type as to achieve surface hardnesses of far greater than 400-450 HV and to minimize the chemical/mechanical corrosion even at heat transfer capacities >80 kW/m. To this end, the heat exchanger is plamatized.

Description

  • The invention pertains to a heat exchanger according to the introductory clause of claim 1. These types of heat exchangers are used in the production or finishing of web-like products in the industry, primarily in calenders.
  • The heat-transfer outputs and surface temperatures required in the new multi-nip calender rolls subject the conventional calender roll materials such as white cast iron, spheroidal graphite iron, and chromium alloy cast iron to loads which exceed their capacity. Forged steel is currently the material which is able to fulfill these requirements. Because adequate forged steel can be hardened and tempered only up to 400-450 HV without sacrificing the advantages of forged steel, the surfaces of these rolls are coated either by electrocoating or by a thermal coating process or they are case-hardened by inductive hardening or flame hardening.
  • Thermally applied surface coatings suffer not only from insufficient reliability but also from the disadvantage of the relatively high porosity of the finished layer. Wear particles are able to penetrate into these pores and into the softer matrix regions and to wash them out. Case-hardened forged steel rolls suffer not only from inadequate tempering properties and the associated lack of sufficient hardness but also from an unfavorable internal stress distribution, caused by the case-hardening process. High tensile stresses in the area of the zone affected by the hardening process destroy the advantages of the good mechanical properties of forged steel.
  • New coating compounds and feed materials being used in papermaking call for increased chemical and mechanical corrosion resistance not only of the barrel of the roll but also of the entire surface exposed to the environment and to the product web. Because of the enormous heat-transfer outputs (>80 kW/m) and the continually increasing heat-transfer temperatures, the contact surfaces exposed to the fluid heat transfer media are subject to ever greater chemical/mechanical corrosion.
  • The invention is based on the task of improving the heat exchanger of the general type in question in such a way that it no longer suffers from the disadvantages mentioned above, especially so that surface hardnesses of considerably more than 400-450 HV are reached, and so that chemical/mechanical corrosion is minimized even at heat-transfer outputs of >80 kW/m.
  • According to the invention, the previously described hardened and tempered forged steel rolls are plasma-treated in the desired areas. The term “plasma-treating” is used in the following as a collective term for “plasma nitriding”, “plasma nitrocarburizing”, “plasma oxidizing”, “plasma carbonitriding”, and “plasma carborizing”. This operation is usually carried out in a vacuum chamber at treatment pressures of 0.3-10 mbars. The treatment temperature is in the range of 400-600° C., depending on the task to be accomplished. Ammonia, nitrogen, methane, and hydrogen are usually used as the process gases. Pressure, temperature, time, and gas type are the parameters used to vary the nature of the layers and the desired surface hardnesses. Hardnesses of up to 1200 HV can be reached on the desired surfaces, and a hardening depth of up to 1 mm is realized. In addition to this extreme hardness, these diffusion layers do not produce any increase in the porosity which could be damaging to the wear process. The porosity of the substrate remains intact. In addition, the resistance to chemical corrosion is enormously improved.
  • Subsurface corrosion, known from thermal spray coatings or even hard chromium-alloy coatings, is not possible when plasma-treating is used. The bonding layer with the surface passivates the surface against oxidative attach. Microcracks, also known from the processes mentioned above, do not develop either.

Claims (10)

1. Temperable, rotatable, rotationally symmetric heat exchanger of hardened and tempered forged steel, especially for the pressing, drying, or smoothing unit of a machine for the production of web-like products such as paper webs or plastic films, which heat exchanger can be tempered preferably with fluid or gaseous heat-transfer media or by an electrical heating system, wherein the heat exchanger is plasma-treated.
2. Heat exchanger according to claim 1, wherein the surfaces of the necks of the rolls are partially or completely plasma-treated.
3. Heat exchanger according to claim 1, wherein the contact surface of the heat exchanger with the web-like product is plasma-treated.
4. Heat exchanger according to claim 1, wherein the surface of the barrel of the heat exchanger is plasma-treated.
5. Heat exchanger according to claim 1, wherein the surface of the roll is plasma-treated.
6. Heat exchanger according to claim 1, wherein the surfaces in contact with the heat-transfer medium are completely or partially plasma-treated.
7. Heat exchanger according to claim 1, wherein a bonding layer is formed at the surface.
8. Heat exchanger according to claim 1, wherein no bonding layer is formed at the surface.
9. Heat exchanger according to claim 1, wherein subsurface corrosion is prevented.
10. Heat exchanger according to claim 1, wherein the plasma-treated calender roll can be used at process temperatures between −20° C. and 500° C.
US10/544,603 2003-02-19 2004-02-13 Plasmatized heat exchanger Abandoned US20060144563A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE10307107 2003-02-19
PCT/EP2004/001340 WO2004074571A1 (en) 2003-02-19 2004-02-13 Plasmatized heat exchanger

Publications (1)

Publication Number Publication Date
US20060144563A1 true US20060144563A1 (en) 2006-07-06

Family

ID=32891762

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/544,603 Abandoned US20060144563A1 (en) 2003-02-19 2004-02-13 Plasmatized heat exchanger

Country Status (5)

Country Link
US (1) US20060144563A1 (en)
EP (1) EP1595025A1 (en)
JP (1) JP2006518013A (en)
CA (1) CA2516951A1 (en)
WO (1) WO2004074571A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110284133A1 (en) * 2008-12-02 2011-11-24 Honda Motor Co., Ltd. Carbonitrided part and process for producing carbonitrided part

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006003386A1 (en) * 2006-01-24 2007-07-26 Reichel, Walter, Dipl.-Ing. Ion implantation unit for roller surfaces, comprises an ion source, an accelerator, a vacuum chamber and a deflection unit

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5123152A (en) * 1989-02-16 1992-06-23 Tampella Telatek Oy Yankee cylinder with a plasma-sprayed carbide coating
US5413473A (en) * 1992-04-30 1995-05-09 Sanyo Electric Co., Ltd. Mechanism for mounting and dismounting mixer in an automatic noodle making machine
US5499936A (en) * 1995-01-12 1996-03-19 Outboard Marine Corporation Monolithic metallic drive shafts which are resistant to corrosion and wear
US5851014A (en) * 1995-07-15 1998-12-22 A E Goetze Gmbh Slide ring seal assembly for the running gears of track-laying vehicles
US5961792A (en) * 1993-09-08 1999-10-05 Tulip Memory Systems, Inc. Method for making titanium or titanium-alloy substrate for magnetic-recording media
US6032440A (en) * 1997-07-16 2000-03-07 Mashinenfabrik Gerd Mosca Gmbh Tensioning device for hoop-casing machines
US6755566B2 (en) * 2001-02-15 2004-06-29 Konrad Damasko Clockwork
US6966954B2 (en) * 2002-10-24 2005-11-22 General Electric Comany Spall propagation properties of case-hardened M50 and M50NiL bearings
US20060162818A1 (en) * 2002-05-08 2006-07-27 Devendra Kumar Plasma-assisted nitrogen surface-treatment

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5123152A (en) * 1989-02-16 1992-06-23 Tampella Telatek Oy Yankee cylinder with a plasma-sprayed carbide coating
US5413473A (en) * 1992-04-30 1995-05-09 Sanyo Electric Co., Ltd. Mechanism for mounting and dismounting mixer in an automatic noodle making machine
US5961792A (en) * 1993-09-08 1999-10-05 Tulip Memory Systems, Inc. Method for making titanium or titanium-alloy substrate for magnetic-recording media
US5499936A (en) * 1995-01-12 1996-03-19 Outboard Marine Corporation Monolithic metallic drive shafts which are resistant to corrosion and wear
US5851014A (en) * 1995-07-15 1998-12-22 A E Goetze Gmbh Slide ring seal assembly for the running gears of track-laying vehicles
US6032440A (en) * 1997-07-16 2000-03-07 Mashinenfabrik Gerd Mosca Gmbh Tensioning device for hoop-casing machines
US6755566B2 (en) * 2001-02-15 2004-06-29 Konrad Damasko Clockwork
US20060162818A1 (en) * 2002-05-08 2006-07-27 Devendra Kumar Plasma-assisted nitrogen surface-treatment
US6966954B2 (en) * 2002-10-24 2005-11-22 General Electric Comany Spall propagation properties of case-hardened M50 and M50NiL bearings

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110284133A1 (en) * 2008-12-02 2011-11-24 Honda Motor Co., Ltd. Carbonitrided part and process for producing carbonitrided part

Also Published As

Publication number Publication date
CA2516951A1 (en) 2004-09-02
JP2006518013A (en) 2006-08-03
WO2004074571A1 (en) 2004-09-02
EP1595025A1 (en) 2005-11-16

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Legal Events

Date Code Title Description
AS Assignment

Owner name: WALZEN IRLE GMBH, GERMANY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HELLENTHAL, LUDWIG;REEL/FRAME:017569/0972

Effective date: 20050616

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION