EP0335999A1 - Method of cleaning metal tubes, in particular cupper-tubes - Google Patents

Method of cleaning metal tubes, in particular cupper-tubes Download PDF

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Publication number
EP0335999A1
EP0335999A1 EP88105615A EP88105615A EP0335999A1 EP 0335999 A1 EP0335999 A1 EP 0335999A1 EP 88105615 A EP88105615 A EP 88105615A EP 88105615 A EP88105615 A EP 88105615A EP 0335999 A1 EP0335999 A1 EP 0335999A1
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EP
European Patent Office
Prior art keywords
tubes
abrasive
thermal treatment
cleaning metal
pipes
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.)
Withdrawn
Application number
EP88105615A
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German (de)
French (fr)
Inventor
Hans Dr. Sick
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.)
Wieland Werke AG
Original Assignee
Wieland Werke AG
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 Wieland Werke AG filed Critical Wieland Werke AG
Priority to EP88105615A priority Critical patent/EP0335999A1/en
Publication of EP0335999A1 publication Critical patent/EP0335999A1/en
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C3/00—Abrasive blasting machines or devices; Plants
    • B24C3/32—Abrasive blasting machines or devices; Plants designed for abrasive blasting of particular work, e.g. the internal surfaces of cylinder blocks
    • B24C3/325—Abrasive blasting machines or devices; Plants designed for abrasive blasting of particular work, e.g. the internal surfaces of cylinder blocks for internal surfaces, e.g. of tubes
    • B24C3/327—Abrasive blasting machines or devices; Plants designed for abrasive blasting of particular work, e.g. the internal surfaces of cylinder blocks for internal surfaces, e.g. of tubes by an axially-moving flow of abrasive particles without passing a blast gun, impeller or the like along the internal surface

Definitions

  • the invention relates to a method for cleaning metal pipes, in particular copper pipes, after drawing by removing lubricant residues.
  • drawing metal pipes it is common to use drawing oil or grease.
  • degrease the metal pipes by immersing them in hot, aqueous alkaline solutions.
  • the disadvantage here is that spot-free drying is difficult to achieve.
  • degrease the metal pipes with chlorine hydrocarbons Environmental and health risks are disadvantageous here.
  • the invention is therefore based on the object of specifying an environmentally friendly method by which the inner tube surface can be cleaned in a simple manner.
  • the object is surprisingly achieved by the process according to the invention in that the oily or greasy residues on the inner surface of the tube are removed by a sandblasting treatment. It has been shown that, in particular in the case of pipes of elongated lengths, the sandblasting of the inner surfaces has a cleaning effect which is similar to that of the methods mentioned above.
  • Sandblasting the inner surface of pipes is known per se.
  • a sandblasting treatment in order to improve the corrosion resistance (cf. for example DE-PS 3,003,228).
  • condenser tubes are also freed of scale and other layers created during thermal treatment.
  • these are regularly deposits that consist of solids of a rather brittle character (oxides). It was not to be expected that oily or greasy deposits could be removed in this way, as they are known to tend to smear.
  • the sandblasting treatment is carried out for 5-30 seconds, the grain size of the blasting medium preferably being chosen between 0.05 and 0.3 mm.
  • corundum is used as the abrasive.
  • the reprocessing can be done in particular by extraction.
  • the reprocessing takes place particularly effectively and economically by thermal treatment of the oiled abrasive in the temperature range of about 900-1,200 ° C., in particular with the addition of oxygen.
  • the thermal treatment is carried out using the eddy current principle, since it is also possible to remove finely divided, solid impurities in the blasting medium, such as oxides or crushed grit.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Cleaning In General (AREA)

Abstract

The invention relates to a method of cleaning metal tubes, in particular copper tubes, after drawing by removing lubricant residues. According to the invention, the oily or greasy residues on the inner surface of the tubes is removed by a sand-blasting treatment. This method, which is not harmful to the environment, has a similarly beneficial cleaning effect as the dip-degreasing methods used hitherto.

Description

Die Erfindung betrifft ein Verfahren zur Reinigung von Metallrohren, insbes. Kupferrohren, nach dem Ziehen durch Entfernung von Schmiermittel-Rückständen.
Beim Ziehen von Metallrohren ist es üblich, Ziehöl oder Ziehfett zu verwenden.
Es ist bekannt, die Metallrohre durch Tauchen in heiße, wässrig-alkalische Lösungen zu entfetten. Nachteilig ist hierbei allerdings, daß ein fleckenfreies Trocknen schwer zu erzielen ist.
Ferner ist es bekannt, die Metallrohre mit Chlor-Kohlenwasser­stoffen zu entfetten. Nachteilig hierbei sind Umwelt- und Gesundheitsrisiken.The invention relates to a method for cleaning metal pipes, in particular copper pipes, after drawing by removing lubricant residues.
When drawing metal pipes, it is common to use drawing oil or grease.
It is known to degrease the metal pipes by immersing them in hot, aqueous alkaline solutions. The disadvantage here, however, is that spot-free drying is difficult to achieve.
It is also known to degrease the metal pipes with chlorine hydrocarbons. Environmental and health risks are disadvantageous here.

Im Falle von Metallrohren ist es häufig (beispielsweise bei Trinkwasser-Leitungsrohren) nur erforderlich, die Innenfläche zu reinigen. Auf der Außenoberfläche wäre dagegen Rest-Ziehfett als Schutzschicht gegen Anlaufen oder Korrosion durchaus er­wünscht.In the case of metal pipes, it is often only necessary (for example in the case of drinking water pipes) to clean the inner surface. On the other hand, residual drawing grease would be desirable as a protective layer against tarnishing or corrosion.

Der Erfindung liegt daher die Aufgabe zugrunde, ein umwelt­freundliches Verfahren anzugeben, nach dem die Rohrinnenfläche auf einfache Weise gereinigt werden kann.
Die Aufgabe wird nach dem erfindungsgemäßen Verfahren über­raschenderweise dadurch gelöst, daß die öligen bzw. fettigen Rückstände auf der Rohrinnenfläche durch eine Sandstrahl-­Behandlung entfernt werden. Es hat sich gezeigt, daß insbes. bei Rohren in gestreckten Längen das Sandstrahlen der Innen­flächen eine ähnlich gute Reinigungswirkung hat wie bei den obengenannten Verfahren.The invention is therefore based on the object of specifying an environmentally friendly method by which the inner tube surface can be cleaned in a simple manner.
The object is surprisingly achieved by the process according to the invention in that the oily or greasy residues on the inner surface of the tube are removed by a sandblasting treatment. It has been shown that, in particular in the case of pipes of elongated lengths, the sandblasting of the inner surfaces has a cleaning effect which is similar to that of the methods mentioned above.

Das Sandstrahlen der Innenoberfläche von Rohren ist zwar an sich bekannt. So ist es beispielsweise zur Entfernung von Belägen aus geglühten Kupferrohren üblich, die Rohr­innenfläche zur Verbesserung der Korrosionsbeständigkeit einer Sandstrahl-Behandlung zu unterwerfen (vgl. beispiels­weise DE-PS 3.003.228).
Auch Kondensatorrohre werden standardmäßig dadurch von Zunder- und anderen bei der thermischen Behandlung ent­standenen Schichten befreit. Regelmäßig sind dies aber Beläge, die aus Feststoffen von eher sprödem Charakter (Oxide) bestehen.
Daß ölige oder fettige Beläge auf diesem Wege entfernbar sind, war nicht zu erwarten, da sie bekanntlich zum Ver­schmieren neigen.
Nach einer besonderen Ausführungsform der Erfindung wird die Sandstrahl-Behandlung für 5 - 30 Sekunden durchgeführt, wobei die Körnung des Strahlmittels vorzugsweise zwischen 0,05 und 0,3 mm zu wählen ist. Nach einer besonderen Aus­führungsform wird Korund als Strahlmittel verwendet.
In der praktischen Durchführung wird vorzugsweise in einem geschlossenen System gearbeitet; d. h. das Strahlmittel wird an einem Rohrende zugeführt und am anderen Rohrende abgesaugt.
Um eine Rückverschmutzung der Rohrinnenfläche durch veröltes Strahlmittel zu vermeiden, wird dieses vorzugsweise ausge­schleust, also entweder komplett oder - bei Umlaufbetrieb - ein Teilstrom. Es empfiehlt sich, das verölte Strahlmittel durch Entölung wiederaufzubereiten. Die Wiederaufbereitung kann insbesondere durch Extraktion erfolgen. Nach einer erfindungsgemäßen Alternative erfolgt die Wiederaufbereitung besonders wirkungsvoll und wirtschaftlich durch thermische Behandlung des verölten Strahlmittels im Temperaturbereich von etwa 900 - 1 200°C, insbesondere unter Sauerstoffzufuhr.Sandblasting the inner surface of pipes is known per se. For example, in order to remove deposits from annealed copper pipes, it is customary to subject the inner surface of the pipe to a sandblasting treatment in order to improve the corrosion resistance (cf. for example DE-PS 3,003,228).
As a standard, condenser tubes are also freed of scale and other layers created during thermal treatment. However, these are regularly deposits that consist of solids of a rather brittle character (oxides).
It was not to be expected that oily or greasy deposits could be removed in this way, as they are known to tend to smear.
According to a special embodiment of the invention, the sandblasting treatment is carried out for 5-30 seconds, the grain size of the blasting medium preferably being chosen between 0.05 and 0.3 mm. According to a special embodiment, corundum is used as the abrasive.
In practice, it is preferred to work in a closed system; ie the abrasive is fed to one end of the pipe and suctioned off at the other end of the pipe.
In order to prevent the inner surface of the pipe from being contaminated again by oiled abrasive, it is preferably discharged, i.e. either completely or - in the case of recirculating operation - a partial flow. It is recommended to reprocess the oiled abrasive by deoiling. The reprocessing can be done in particular by extraction. According to an alternative according to the invention, the reprocessing takes place particularly effectively and economically by thermal treatment of the oiled abrasive in the temperature range of about 900-1,200 ° C., in particular with the addition of oxygen.

In diesem Temperaturbereich brennt das Öl vollständig ab.
In zweckmäßiger Ausgestaltung dieses Verfahrensschrittes erfolgt die thermische Behandlung unter Verwendung des Wirbelstromprinzips, da sich dabei auch feinteilige, feste Verunreinigungen im Strahlmittel, wie etwa Oxide oder zer­trümmertes Strahlkorn, austragen lassen.The oil burns off completely in this temperature range.
In an expedient embodiment of this process step, the thermal treatment is carried out using the eddy current principle, since it is also possible to remove finely divided, solid impurities in the blasting medium, such as oxides or crushed grit.

Die Erfindung wird anhand des folgenden Ausführungsbeispieles näher erläutert:The invention is explained in more detail using the following exemplary embodiment:

Zur Untersuchung standen auf die Endabmessung 22 x 1 mm gezogene Rohre aus desoxidiertem Kupfer in gestreckter Länge von 5 m zur Verfügung. Die ziehharten Rohre wiesen im Mittel einen Schmiermittel-Rückstand (ausgedrückt in Kohlenstoff­belegung) von 1,2 mg C/dm² auf.
Nach dem erfindungsgemäßen Verfahren wurden die Rohrinnen­flächen 10 Sekunden lang mit Korund (Körnung = 0,09 - 0,25 mm) bei einem Druck von 3,5 bar sandgestrahlt. Anschließend wurde mit Druckluft ausgeblasen. Es verblieb ein Rückstand von 0,12 mg C/dm².
Zum Vergleich wurden Rohre einer Tauchentfettung mit Perchlor­äthylen unterzogen. Es ergab sich ein Rückstand von 0,10 mg C/dm².
Im Rahmen der Meßgenauigkeit sind also die Rückstandswerte etwa identisch. Bei den erfindungsgemäß behandelten Rohren zeigt jedoch die Innenoberfläche ein gleichmäßig mattiertes Aus­sehen, wobei evtl. aus dem Ziehvorgang resultierende Hetero­genitäten (Ziehriefen usw.) beseitigt sind.For the investigation, 22 x 1 mm drawn tubes made of deoxidized copper with an elongated length of 5 m were available. The tough pipes had an average lubricant residue (expressed in carbon coverage) of 1.2 mg C / dm².
In the process according to the invention, the inner tube surfaces were sandblasted with corundum (grain size = 0.09-0.25 mm) at a pressure of 3.5 bar for 10 seconds. It was then blown out with compressed air. A residue of 0.12 mg C / dm² remained.
For comparison, tubes were subjected to dip degreasing with perchlorethylene. A residue of 0.10 mg C / dm² resulted.
Within the scope of the measuring accuracy, the residue values are approximately identical. In the case of the pipes treated according to the invention, however, the inner surface has a uniformly matt appearance, any heterogeneities (drawing grooves, etc.) resulting from the drawing process being eliminated.

Claims (11)

1. Verfahren zur Reinigung von Metallrohren, insbes. Kupfer­rohren, nach dem Ziehen durch Entfernung von Schmiermittel­rückständen,
dadurch gekennzeichnet,
daß die öligen bzw. fettigen Rückstände auf der Rohrinnen­fläche durch eine Sandstrahl-Behandlung entfernt werden.1. Process for cleaning metal pipes, in particular copper pipes, after drawing by removing lubricant residues,
characterized,
that the oily or greasy residues on the inside of the pipe are removed by sandblasting. 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet,
daß die Sandstrahl-Behandlung für 5 - 30 Sekunden durchge­führt wird.2. The method according to claim 1, characterized in that
that the sandblasting treatment is carried out for 5-30 seconds. 3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet,
daß die Körnung des Strahlmittels 0,05 - 0,3 mm beträgt.3. The method according to claim 1 or 2, characterized in
that the abrasive grain size is 0.05 - 0.3 mm. 4. Verfahren nach einem oder mehreren der Ansprüche 1 - 3, dadurch gekennzeichnet,
daß als Strahlmittel Korund verwendet wird.4. The method according to one or more of claims 1-3, characterized in
that corundum is used as the abrasive. 5. Verfahren nach einem oder mehreren der Ansprüche 1 - 4, dadurch gekennzeichnet,
daß das Strahlmittel in einem geschlossenen System geführt wird.5. The method according to one or more of claims 1-4, characterized in
that the blasting agent is guided in a closed system. 6. Verfahren nach Anspruch 5, dadurch gekennzeichnet,
daß veröltes Strahlmittel ausgeschleust wird.6. The method according to claim 5, characterized in
that oiled abrasive is discharged. 7. Verfahren nach Anspruch 6, dadurch gekennzeichnet,
daß das verölte Strahlmittel durch Entölung wiederaufbe­reitet wird.7. The method according to claim 6, characterized in that
that the oiled abrasive is reprocessed by deoiling. 8. Verfahren nach Anspruch 7, dadurch gekennzeichnet,
daß die Wiederaufbereitung durch Extraktion erfolgt.8. The method according to claim 7, characterized in that
that the reprocessing is done by extraction. 9. Verfahren nach Anspruch 7, dadurch gekennzeichnet,
daß die Wiederaufbereitung durch thermische Behandlung im Temperaturbereich von etwa 900 - 1 200°C erfolgt.9. The method according to claim 7, characterized in
that the reprocessing takes place by thermal treatment in the temperature range of about 900-1,200 ° C. 10. Verfahren nach Anspruch 9, dadurch gekennzeichnet,
daß die thermische Behandlung unter Sauerstoffzufuhr erfolgt.10. The method according to claim 9, characterized in
that the thermal treatment takes place with the addition of oxygen. 11. Verfahren nach Anspruch 9 oder 10, dadurch gekennzeichnet,
daß die thermische Behandlung unter Verwendung des Wirbelschichtprinzips erfolgt.11. The method according to claim 9 or 10, characterized in
that the thermal treatment is carried out using the fluidized bed principle.
EP88105615A 1988-04-08 1988-04-08 Method of cleaning metal tubes, in particular cupper-tubes Withdrawn EP0335999A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP88105615A EP0335999A1 (en) 1988-04-08 1988-04-08 Method of cleaning metal tubes, in particular cupper-tubes

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP88105615A EP0335999A1 (en) 1988-04-08 1988-04-08 Method of cleaning metal tubes, in particular cupper-tubes

Publications (1)

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EP0335999A1 true EP0335999A1 (en) 1989-10-11

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0976845A1 (en) * 1998-07-30 2000-02-02 Outokumpu Oyj Method for producing copper tubes
EP1167563A1 (en) * 2000-06-20 2002-01-02 Outokumpu Oyj Method for manufacturing internally coated copper or copper alloy pipes

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1070867A (en) * 1964-02-11 1967-06-07 Pangborn Corp Pressure blast apparatus
DE2337022A1 (en) * 1973-07-20 1975-02-13 Liege Usines Cuivre Zinc Removing drawing lubricants from copper tubes before annealing - by alternately blowing into the bores a degreasant and steam
DE3003228B1 (en) * 1980-01-30 1981-03-26 Wieland-Werke Ag, 89079 Ulm Process for improving the corrosion resistance of copper installation pipes
DE3408828A1 (en) * 1984-03-10 1985-09-12 Rudolf 4834 Harsewinkel Ristow Method for cleaning surfaces, in particular inner surfaces of ventilation systems and system parts
US4579596A (en) * 1984-11-01 1986-04-01 Union Carbide Corporation In-situ removal of oily deposits from the interior surfaces of conduits

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1070867A (en) * 1964-02-11 1967-06-07 Pangborn Corp Pressure blast apparatus
DE2337022A1 (en) * 1973-07-20 1975-02-13 Liege Usines Cuivre Zinc Removing drawing lubricants from copper tubes before annealing - by alternately blowing into the bores a degreasant and steam
DE3003228B1 (en) * 1980-01-30 1981-03-26 Wieland-Werke Ag, 89079 Ulm Process for improving the corrosion resistance of copper installation pipes
DE3408828A1 (en) * 1984-03-10 1985-09-12 Rudolf 4834 Harsewinkel Ristow Method for cleaning surfaces, in particular inner surfaces of ventilation systems and system parts
US4579596A (en) * 1984-11-01 1986-04-01 Union Carbide Corporation In-situ removal of oily deposits from the interior surfaces of conduits

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0976845A1 (en) * 1998-07-30 2000-02-02 Outokumpu Oyj Method for producing copper tubes
EP1167563A1 (en) * 2000-06-20 2002-01-02 Outokumpu Oyj Method for manufacturing internally coated copper or copper alloy pipes

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