CA2516951A1 - Plasma-treated heat exchangers - Google Patents
Plasma-treated heat exchangers Download PDFInfo
- Publication number
- CA2516951A1 CA2516951A1 CA002516951A CA2516951A CA2516951A1 CA 2516951 A1 CA2516951 A1 CA 2516951A1 CA 002516951 A CA002516951 A CA 002516951A CA 2516951 A CA2516951 A CA 2516951A CA 2516951 A1 CA2516951 A1 CA 2516951A1
- Authority
- CA
- Canada
- Prior art keywords
- heat exchanger
- plasma
- treated
- exchanger according
- 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
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
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
TRANSLATrON (T~!-651PCT .-- original) wo 2004/04,571 A1 PLASMA-TREATED HEAT EXCHANGERS
The invention pexta,ins to a heat exchanger according to the introductory clause of Claim 1. These types~of heat exchangers axe 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 mufti-nip calender rolls subject the conventional calender roll materia~.s such as white cast iron, spheroidal graphite iron, and chromium alloy cast~irorz to loads which.
exceed their capacity. Forged steel is currentJ.y 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 ox by a thermal coating process or they are case-hardened by inductive hardening or flame hardening.
Thermally applied surface coatings suffer not oxzly from insufficient reliability but also from the disadvantage of the relatively high porosity of the finished layer. dear 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 fxom 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 paperma~ing 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 coxxosion.
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 longex suffers from the disadvantages mentioned above, especially so that surface hardnesses of considerably more than 400-450 HV axe reached, and so that chemical/mechanical corrosion is minimized eaen at heat-transfer outputs of % 80 kw/m.
According to the invention, the previously described hardened and tempered forged steel rolls axe plasma-treated in the desired areas. The term "plasma-treating" is used i,n 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.~-10 mbars. The treatment temperature is in the range of 404-600°C, depending on the task to be accompl~,shed. 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. zn.
addition to this extreme hardness, these diffusion layers do npt produce any i,ncxease 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.
The invention pexta,ins to a heat exchanger according to the introductory clause of Claim 1. These types~of heat exchangers axe 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 mufti-nip calender rolls subject the conventional calender roll materia~.s such as white cast iron, spheroidal graphite iron, and chromium alloy cast~irorz to loads which.
exceed their capacity. Forged steel is currentJ.y 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 ox by a thermal coating process or they are case-hardened by inductive hardening or flame hardening.
Thermally applied surface coatings suffer not oxzly from insufficient reliability but also from the disadvantage of the relatively high porosity of the finished layer. dear 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 fxom 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 paperma~ing 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 coxxosion.
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 longex suffers from the disadvantages mentioned above, especially so that surface hardnesses of considerably more than 400-450 HV axe reached, and so that chemical/mechanical corrosion is minimized eaen at heat-transfer outputs of % 80 kw/m.
According to the invention, the previously described hardened and tempered forged steel rolls axe plasma-treated in the desired areas. The term "plasma-treating" is used i,n 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.~-10 mbars. The treatment temperature is in the range of 404-600°C, depending on the task to be accompl~,shed. 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. zn.
addition to this extreme hardness, these diffusion layers do npt produce any i,ncxease 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 suxface against oxidative attach. Microcracks, also known from the processes mentioned above, do not develop either.
Claims (10)
1. Temperable, rotatable, rotationally symmetric heat exchanger, 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, characterized in that the heat exchanger is plasma-treated.
2. Heat exchanger according to Claim 1, characterized in that the surfaces of the necks of the rolls are partially or completely plasma-treated.
3. Heat exchanger according to Claim 1 or Claim 2, characterized in that the contact surface of the heat exchanger with the web-like product is plasma-treated.
4. Heat exchanger according to one of Claims 1-3, characterized in that the surface of the barrel of the heat exchanger is plasma-treated.
5. Heat exchanger according to one of Claims 1-4, characterized in that the surface of the roll is plasma-treated.
6. Heat exchanger according to Claim 1 or Claim 3, characterized in that the surfaces in contact with the heat transfer medium are completely or partially plasma-treated.
7. Heat exchanger according to one of Claims 1-6, characterized in that a bonding layer is formed at the surface.
8. Heat exchanger according to one of Claims 1-6, characterized in that no bonding layer is formed at the surface.
9. Heat exchanger according to one of Claims 1-8, characterized in that subsurface corrosion is prevented.
10. Heat exchanger according to one of Claims 1-9, characterized in that the plasma-treated calender roll can be used at process temperatures between -20°C and 500°C.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE10307107 | 2003-02-19 | ||
| DE10307107.5 | 2003-02-19 | ||
| PCT/EP2004/001340 WO2004074571A1 (en) | 2003-02-19 | 2004-02-13 | Plasmatized heat exchanger |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2516951A1 true CA2516951A1 (en) | 2004-09-02 |
Family
ID=32891762
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002516951A Abandoned CA2516951A1 (en) | 2003-02-19 | 2004-02-13 | Plasma-treated heat exchangers |
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) |
Families Citing this family (2)
| 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 |
| JP5241455B2 (en) * | 2008-12-02 | 2013-07-17 | 新日鐵住金株式会社 | Carbonitriding member and method for producing carbonitriding member |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI82094C (en) * | 1989-02-16 | 1997-09-09 | Valmet Corp | Anvaendning av en legering av ett metallpulver och en carbid eller nitride innefattande belaeggningskomposition Foer en i en pappersmaskin anvaendbar yankeecylinder |
| JPH05304872A (en) * | 1992-04-30 | 1993-11-19 | Sanyo Electric Co Ltd | Mixer-mounting structure of automatic noodle-making machine |
| US5707705A (en) * | 1993-09-08 | 1998-01-13 | Tulip Memory Systems, Inc. | 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 |
| DE19525863A1 (en) * | 1995-07-15 | 1997-01-16 | Ae Goetze Gmbh | Mechanical seal for the tracks of caterpillars |
| DE19730449A1 (en) * | 1997-07-16 | 1999-01-21 | Mosca G Maschf | Clamping device for strapping machines |
| US6755566B2 (en) * | 2001-02-15 | 2004-06-29 | Konrad Damasko | Clockwork |
| US7465362B2 (en) * | 2002-05-08 | 2008-12-16 | Btu International, Inc. | 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 |
-
2004
- 2004-02-13 EP EP04710849A patent/EP1595025A1/en not_active Withdrawn
- 2004-02-13 WO PCT/EP2004/001340 patent/WO2004074571A1/en active Application Filing
- 2004-02-13 JP JP2006501825A patent/JP2006518013A/en active Pending
- 2004-02-13 US US10/544,603 patent/US20060144563A1/en not_active Abandoned
- 2004-02-13 CA CA002516951A patent/CA2516951A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| JP2006518013A (en) | 2006-08-03 |
| WO2004074571A1 (en) | 2004-09-02 |
| US20060144563A1 (en) | 2006-07-06 |
| EP1595025A1 (en) | 2005-11-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |