DE2448292A1 - Electrostatic powder spraying for pre-heated metal tubes - tube length is heated to different temperatures - Google Patents

Electrostatic powder spraying for pre-heated metal tubes - tube length is heated to different temperatures

Info

Publication number
DE2448292A1
DE2448292A1 DE19742448292 DE2448292A DE2448292A1 DE 2448292 A1 DE2448292 A1 DE 2448292A1 DE 19742448292 DE19742448292 DE 19742448292 DE 2448292 A DE2448292 A DE 2448292A DE 2448292 A1 DE2448292 A1 DE 2448292A1
Authority
DE
Germany
Prior art keywords
pipe
heated
tube
length
temperature
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.)
Granted
Application number
DE19742448292
Other languages
German (de)
Other versions
DE2448292B2 (en
DE2448292C3 (en
Inventor
Willi Ing Grad Domalski
Walter Dipl Ing Dr Zimnik
Rudolf Dipl Ing Zobl
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.)
SALZGITTER PEINE STAHLWERKE
Original Assignee
SALZGITTER PEINE STAHLWERKE
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 SALZGITTER PEINE STAHLWERKE filed Critical SALZGITTER PEINE STAHLWERKE
Priority to DE19742448292 priority Critical patent/DE2448292C3/en
Priority claimed from DE19742448292 external-priority patent/DE2448292C3/en
Publication of DE2448292A1 publication Critical patent/DE2448292A1/en
Publication of DE2448292B2 publication Critical patent/DE2448292B2/en
Application granted granted Critical
Publication of DE2448292C3 publication Critical patent/DE2448292C3/en
Expired legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
    • B05D7/146—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies to metallic pipes or tubes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D1/00—Processes for applying liquids or other fluent materials
    • B05D1/02—Processes for applying liquids or other fluent materials performed by spraying
    • B05D1/04—Processes for applying liquids or other fluent materials performed by spraying involving the use of an electrostatic field
    • B05D1/06—Applying particulate materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
    • B05D3/0218—Pretreatment, e.g. heating the substrate

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)

Abstract

During the electrostatic spraying of powderized materials onto pre-heated metal tubes, a relative speed in a longitudinal direction of the tube exists between it and the spray unit. the length of the tube is pre-heated to different temperatures, so that the tube end, where the spraying commences, has the lowest temperature. The temperature increases over the length of the tube, in a linear way, until a maximum value is reached, so that the temperature is always constant at the point of spraying. The optimal qualities of the powdered material is thereby maintained since the heating is kept within narrow tolerances.

Description

Die Erfindung betrifft ein Verfahren zum elektrostatischen Aufsprühen pulverförmiger Stoffe auf vorerhitzte Rohre aus Metall, wobei während des Aufsprühens zwischen Aufsprüheinrichtung und Rohr eine Relativgeschwindigkeit in Rohrlängsrichtung besteht.The invention relates to a method for electrostatically spraying powdery substances onto preheated tubes Metal, with between spraying device during spraying and pipe a relative speed in the pipe longitudinal direction consists.

Es ist bekannt, das zu beschichtende Rohr nach seiner Reinigung auf eine Temperatur zu erhitzen, die ausreicht, das anschließend aufgesprühte Material zum Schmelzen und Aushärten zu bringen. Bei einer Beschichtung mit Epoxidharzpulver liegt diese Temperatur bei bekannten Verfahren in der Größenordnung von 230 bis 260° C (siehe DT-OS 2 256 865). Ein derartig aufgeheiztes Rohr durchläuft unter kontinuierlicher Rotation 'um seine Längsachse eine Pulverbesprühungskammer, in der die pulverförmigen elektrostatisch polarisierten Stoffe auf den Rohrmantel aufgesprüht werden. Da die Pulversprühkammer im Vergleich zur Länge des zu beschichtenden Rohres verhältnismäßig kurz ist, beträgt die Durchlaufzeit einesIt is known that the pipe to be coated after it has been cleaned to heat to a temperature sufficient to melt and harden the subsequently sprayed material. When coated with epoxy resin powder, this temperature is in the order of magnitude of 230 to 260 ° C. in known processes (see DT-OS 2 256 865). Such a heated tube passes through a with continuous rotation 'about its longitudinal axis Powder spray chamber in which the powdery electrostatic polarized substances are sprayed onto the pipe jacket. Because the powder spray chamber compared to the length of the to be coated Pipe is relatively short, the lead time is one

609817/0994609817/0994

Rohres durch die Pulversprühkammer je nach Länge und Vorschubgeschwindigkeit mehrere Minuten. Daher weist der zuerst beschichtete Teil des Rohres eine höhere örtliche Beschichtungstemperatur auf als das zuletzt beschichtete Rohrende, dessen Temperatur während der Aufsprühzeit über die Rohrlänge durch Wärmestrahlung und dergleichen abgesunken ist.Tube through the powder spray chamber depending on the length and feed speed several minutes. Therefore, the first coated part of the pipe has a higher local coating temperature than the last coated pipe end, its temperature during the spraying time over the length of the pipe Thermal radiation and the like has decreased.

Eingehende Untersuchungen haben gezeigt, daß die aufzusprühenden pulverförmigen Stoffe nur in einem verhältnismäßig engen Temperaturbereich ihre optimalen Eigenschaften entwickeln. Schwankungen in der Beschichtungstemperatur beeinträchtigen daher die Qualität der Beschichtung.In-depth investigations have shown that the powdery substances to be sprayed on only in a relatively narrow temperature range develop their optimal properties. Fluctuations in the coating temperature therefore affect the quality the coating.

Ausgehend von dieser Erkenntnis liegt der Erfindung die Aufgabe zugrun-de, die örtliche Beschichtungstemperatur über die gesamte Rohrlänge möglichst konstant zu halten·On the basis of this knowledge, the object of the invention is to determine the local coating temperature over the entire To keep the pipe length as constant as possible

Diese Aufgabe vird gemäß der Erfindung dadurch gelöst, daß das Rohr über seine Länge auf unterschiedliche Temperaturen vorerhitzt wird derart, daß das Rohrende, an dem die Beschichtung beginnt, die niedrigste Aufheiztemperatur aufweist, die über die Rohrlänge angenähert linear auf einen maximalen Viert ansteigt, damit die Rohrtemperatur am jeweiligen Beschichtungsort annähernd gleich ist.This object is achieved according to the invention in that the tube is preheated to different temperatures over its length is such that the pipe end at which the coating begins has the lowest heating temperature that is above the Pipe length increases approximately linearly to a maximum of four, so that the pipe temperature at the respective coating location is approximately is equal to.

Beispielexample

Es soll ein Stahlrohr beschichtet werden von 811 mm Durchmesser, 9,3 mm Wandstärke und 15 mm Länge. Das Material hat die Güte PSX 70. Zwischen Rohr und Spritzsegment beträgt die Relativbewegung 3 m/min. Angestrebt wird eine konstante örtliche Beschichtungstemperatur von 290° C, Dieses Ziel wurde erreicht durchA steel pipe with a diameter of 811 mm, a wall thickness of 9.3 mm and a length of 15 mm is to be coated. The material is good PSX 70. The relative movement between the pipe and the spray segment is 3 m / min. A constant local coating temperature is aimed for of 290 ° C, this goal was achieved by

— 3 —- 3 -

6098 17/09946098 17/0994

unterschiedliche Vorwärmung des Rohres derart, daß am Rohranfang eine Temperatur von 300° C gemessen wurde, die zum Rohrende angenähert linear auf eine Temperatur von 38O C anstieg.different preheating of the pipe in such a way that a temperature of 300 ° C was measured at the beginning of the pipe, that at the end of the pipe rose approximately linearly to a temperature of 38O C.

Das Diagramm zeigt den Temperaturverlauf über ein I5 m langes Rohr.The diagram shows the temperature profile over a length of 15 m Pipe.

6098 17/0 9 946098 17/0 9 94

Claims (1)

Patentanspruch:Claim: Verfahren zum elektrostatischen Aufsprühen pulverförmiger Stoffe auf vorerhitzte Rohre aus Metall, wobei während des Aufsprühens zwischen Aufsprüheinrichtung und Rohr eine Relativgeschwindigkeit in Rohrlängsrichtung besteht, dadurch gekennzeichnet, daß das Rohr über seine Länge auf unterschiedliche Temperaturen vorerhitzt wird derart, daß das Rohrende, an dem die Beschichtung beginnt, die niedrigste Aufheiztemperatur aqfweist, die über die Rohrlänge angenähert linear auf einen maximalen Wert ansteigt, damit die Rohrtemperatur am jeweiligen Beschichtungsort annähernd gleich ist.Process for the electrostatic spraying of powdery substances on preheated metal tubes, while being sprayed there is a relative speed in the longitudinal direction of the pipe between the spraying device and the pipe, characterized in that that the tube is preheated over its length to different temperatures in such a way that the tube end on which the coating begins, the lowest heating temperature aqf shows, which is approximately linear over the length of the pipe to a maximum value increases so that the pipe temperature at the respective coating location is approximately the same. Werner GrammWerner Gramm Patentanwalt
Gr/Im Patent attorney
Gr / In 609817/0994609817/0994
DE19742448292 1974-10-10 Process for the electrostatic spraying of powdery substances onto preheated metal tubes Expired DE2448292C3 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE19742448292 DE2448292C3 (en) 1974-10-10 Process for the electrostatic spraying of powdery substances onto preheated metal tubes

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19742448292 DE2448292C3 (en) 1974-10-10 Process for the electrostatic spraying of powdery substances onto preheated metal tubes

Publications (3)

Publication Number Publication Date
DE2448292A1 true DE2448292A1 (en) 1976-04-22
DE2448292B2 DE2448292B2 (en) 1976-11-18
DE2448292C3 DE2448292C3 (en) 1977-06-30

Family

ID=

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2940388A1 (en) * 1979-10-05 1981-04-16 Hoechst Ag, 6000 Frankfurt METHOD FOR COATING METAL TUBES
US8038829B2 (en) 2006-02-22 2011-10-18 Shawcor Ltd. Coating method for pipe having weld bead

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2940388A1 (en) * 1979-10-05 1981-04-16 Hoechst Ag, 6000 Frankfurt METHOD FOR COATING METAL TUBES
US8038829B2 (en) 2006-02-22 2011-10-18 Shawcor Ltd. Coating method for pipe having weld bead

Also Published As

Publication number Publication date
DE2448292B2 (en) 1976-11-18

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Legal Events

Date Code Title Description
C3 Grant after two publication steps (3rd publication)
E77 Valid patent as to the heymanns-index 1977
8339 Ceased/non-payment of the annual fee