EP0173896A1 - Apparatus for applying a low boiling liquefied gas to the coatings in pipes - Google Patents

Apparatus for applying a low boiling liquefied gas to the coatings in pipes Download PDF

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Publication number
EP0173896A1
EP0173896A1 EP85110197A EP85110197A EP0173896A1 EP 0173896 A1 EP0173896 A1 EP 0173896A1 EP 85110197 A EP85110197 A EP 85110197A EP 85110197 A EP85110197 A EP 85110197A EP 0173896 A1 EP0173896 A1 EP 0173896A1
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EP
European Patent Office
Prior art keywords
arms
coatings
pipes
tube
low boiling
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Withdrawn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
EP85110197A
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German (de)
French (fr)
Inventor
Albert Dr. Köhler
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.)
Messer Griesheim GmbH
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Messer Griesheim 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 Messer Griesheim GmbH filed Critical Messer Griesheim GmbH
Publication of EP0173896A1 publication Critical patent/EP0173896A1/en
Withdrawn legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B13/00—Machines or plants for applying liquids or other fluent materials to surfaces of objects or other work by spraying, not covered by groups B05B1/00 - B05B11/00
    • B05B13/06—Machines or plants for applying liquids or other fluent materials to surfaces of objects or other work by spraying, not covered by groups B05B1/00 - B05B11/00 specially designed for treating the inside of hollow bodies
    • B05B13/0627—Arrangements of nozzles or spray heads specially adapted for treating the inside of hollow bodies

Definitions

  • the invention relates to a device for applying a low-boiling liquefied gas to coatings in pipes, according to the preamble of claim 1.
  • the term pipes is also intended to include long cylindrical vessels.
  • the invention has for its object to provide a device that makes it possible to apply a low-boiling liquefied gas to the inner surface of internally coated pipes, even if it is pipes with small diameters.
  • Fig.1 u. 2 shows a tube 1 which has a coating 2 on the inside which is to be removed.
  • a self-centering guide star which is arranged in the interior of the tube 1 and which can be displaced in the interior of the tube 1 serves for this purpose.
  • the guide star consists of a central piece 3, in which a spray nozzle 4 for liquid nitrogen is attached.
  • the nitrogen is supplied through a tube 5, which is surrounded by a jacket made of polyamide for insulation.
  • elastic arms 6 are attached at an angle of 120 °.
  • the free ends of the elastic arms 6 are provided with support rollers 7 which roll along the coating 2.
  • the elastic arms 6 are also inclined in the direction of movement to the tube axis.
  • the direction of movement of the guide star is indicated by an arrow 8.
  • the movement is carried out by pushing the guide star through the tube 1 by means of the tube 5.
  • the tube 5 is mounted in a ball bushing 9, the one Linear feedthrough enabled.
  • the ball bushing 9 itself is fastened in a flange 10 which is pressed onto the pipe end with the aid of three tie rods 11.
  • the counter bearing for the tie rods 11 form three small blocks 12 which are attached to the outside of the tube at an angle of 120 °.
  • the guide star When starting up, the guide star is slowly pushed through the tube in the direction of arrow 8 and the coating 2 is progressively sprayed with liquid nitrogen. The developing nitrogen gas escapes through the open pipe end. As soon as the coating 2 is permanently brittle, the flange 10 is removed, the guide star is removed and the coating is removed by mechanical action. As a rule, light hammer blows on the outside of the tube are sufficient. If the coating is not to be removed in a tube, but in a long cylindrical container, 10 openings must be provided in the flange through which the gaseous nitrogen can escape.
  • the arms 6 consist of a material which also has elastic properties even in the low temperature range.
  • the arms are advantageously formed from a plastic with corresponding properties as leaf springs. This structure is particularly simple and robust. It is advantageous if the arms 6 are attached to the central piece 3 in an easily replaceable manner. Arms 6 of different lengths can then be fastened on the central piece 3, so that an adaptation to different pipe diameters is possible.
  • the flange 10 it is expedient to design the flange 10 so that it can be attached to different pipe diameters.
  • the holes for Recording the tie rod 6 in the flange have different distances from the center of the flange. In the case of pipes with a large diameter, the holes located further inside are screwed in so that no gas can escape through them.
  • the elastic arms 6 are also possible. They can also be arranged vertically on the central piece 3 and must then be elastic perpendicular to the pipe axis. This is e.g. possible with the help of coil springs, but the material embrittlement that begins at low temperatures sets such constructions limits.
  • the central piece of the guide star is designed as a tube section 13, at the ends of which three elastic arms 6 are each arranged at 120 °. The arms 6 are inclined towards the tube axis on both sides.
  • the nitrogen is supplied through an elastic insulating tube 14, which is guided through a bore in the flange 10.
  • the guide star is pulled through the tube 1 by means of a chain 15.
  • This modified device can also be moved through a curved tube, since the insulating tube 14 and the chain 15 adapt to the tube curvature. Because of the elasticity of the arms 6, even relatively sharp curvatures can be traversed.

Abstract

Coatings, for example bonded sheets or rubber coatings can be removed by making them brittle by means of a liquified gas with a low boiling point and then knocking or scraping them off. However, because of the spatially restricted conditions this method presents difficulties with internally coated pipes and containers up to approximately 1 m diameter. Coatings (2); in pipes (1) and containers of this kind can be made brittle in a simple manner with a device which is constructed as a longitudinally displaceable guide star. This consists of a central element (3; 13) for receiving a spray nozzle (4) for the liquified gas with a low boiling point. Elastic arms (6) are attached to this central element by one end. By the other end the arms are supported in a sliding manner on the coating of the pipe or container. The guide star is pushed with the feed pipe (5) for the liquified gas with a low boiling point through the pipe or the container. <IMAGE>

Description

Die Erfindung betrifft eine Vorrichtungen zum Aufbringen eines tiefsiedenden verflüssigten Gases auf Beschichtungen in Rohren, nach dem Oberbegriff des Anspruches 1. Der Begriff Rohre soll hierbei auch lange zylindrische Gefäße mit umfassen.The invention relates to a device for applying a low-boiling liquefied gas to coatings in pipes, according to the preamble of claim 1. The term pipes is also intended to include long cylindrical vessels.

Rohre werden häufig heute von innen beschichtet, um das Grundmaterial, meiste Stahl, vor Korrosion und Angriffen von chemisch aggressiven Medien zu schützen, wenn diese durch die Rohre transportiert werden. Wenn die Beschichtung beschädigt worden ist, muß insgesamt neu beschichtet werden. Hierzu muß zuvor die gesamte Beschichtung sauber entfernt werden. Auch dann, wenn das ganze Rohr ausgetauscht wird, ist es wünschenswert, die Beschichtung zu entfernen. Der Rohrwerkstoff ist nämlich oft wertvoll. tToday, pipes are often coated from the inside to protect the base material, most of the steel, from corrosion and attack by chemically aggressive media when they are transported through the pipes. If the coating has been damaged, the entire coating must be re-coated. To do this, the entire coating must first be removed cleanly. Even if the entire tube is replaced, it is desirable to remove the coating. The pipe material is often valuable. t

Jedoch nur wenn die Beschichtung entfernt worden ist, kann das Rohr problemlos verschrottet und wieder eingeschmolzen werden.However, only when the coating has been removed can the pipe be easily scrapped and melted again.

Es ist grundsätzlich möglich, Beschichtungen durch Pyrolyse oder Abbrennen zu entfernen. Hierbei werden umweltbelastende Stoffe frei. Diese Umweltbelastung kann vermieden werden, wenn man die Beschichtung durch Benetzen mit einem tiefsiedenden verflüssigten Gas versprödet und anschließend durch mechanische Einwirkung absprengt. Die versprödete Beschichtung kann beispielsweise mit einem Schaber oder durch leichte Schläge mit einem Hammer entfernt werden. Eine solche Verfahrensweise ist beispielsweise aus der DE-OS 29 06 496 bekannt. Bei Rohren bis zu einem Durchmesser von etwa 1m bereitet es aber wegen der räumlichen Enge außerordentliche Schwierigkeiten, das tiefsiedende verflüssigte Gas, normalerweise Stickstoff, auf die Rohrinnenwand in ausreichender Menge aufzubringen.In principle, it is possible to remove coatings by pyrolysis or by burning. This releases environmentally harmful substances. This environmental impact can be avoided if the coating is embrittled by wetting it with a low-boiling liquefied gas and then blasted off by mechanical action. The embrittled coating can be removed, for example, with a scraper or by light blows with a hammer. Such a procedure is known for example from DE-OS 29 06 496. For pipes up to a diameter of about 1m, however, it is extremely difficult to apply the low-boiling liquefied gas, usually nitrogen, to the inner wall of the pipe in sufficient quantities because of the spatial confinement.

Der Erfindung liegt die Aufgabe zugrunde, eine Vorrichtung zu schaffen, die es ermöglicht, auf die Innenoberfläche von innenbeschichteten Rohren ein tiefsiedendes verflüssigtes Gas aufzubringen, und zwar auch dann, wenn es sich um Rohre mit kleinen Durchmessern handelt.The invention has for its object to provide a device that makes it possible to apply a low-boiling liquefied gas to the inner surface of internally coated pipes, even if it is pipes with small diameters.

Ausgehend von dem im Oberbegriff des Anspruches 1 berücksichtigten Stand der Technik ist diese Aufgabe erfindungsgemäß gelöst mit den im kennzeichnenden Teil des Anspruches 1 angegebenen Merkmalen.Starting from the prior art taken into account in the preamble of claim 1, this object is achieved according to the invention with the features specified in the characterizing part of claim 1.

Vorteilhafte Weiterbildungen der Erfindung sind in den Unteransprüchen angegeben.Advantageous developments of the invention are specified in the subclaims.

Zwei Ausführungsbeispiele der Erfindung sollen anhand der beigefügten Zeichnungen erläutert werden.Two embodiments of the invention are based on the attached drawings are explained.

Es zeigen:

  • Fig.1 eine bevorzugte Ausführungsform der erfindungsgemäßen Vorrichtung im Schnitt,
  • Fig.2 einen Schnitt entlang der Linie A-A in Fig.1,
  • Fig.3 eine Abwandlung der erfindungsgemäßen Vorrichtung, welche auch in gekrümmten Rohren verwendet werden kann.
Show it:
  • 1 shows a preferred embodiment of the device according to the invention in section,
  • 2 shows a section along the line AA in FIG. 1,
  • 3 shows a modification of the device according to the invention, which can also be used in curved tubes.

In den Fig.1 u. 2 ist ein Rohr 1 dargestellt, welches im Innern eine Beschichtung 2 besitzt, die entfernt werden soll. Hierzu dient erfindungsgemäß ein im Innern des Rohres 1 angeordneter, sich selbstzentrierender Führungsstern, der im Innern des Rohres 1 verschoben werden kann. Der Führungsstern besteht aus einem Zentralstück 3, in welchem eine Sprühdüse 4 für flüssigen Stickstoff befestigt ist. Die Stickstoffzufuhr erfolgt durch ein Rohr 5, welches zur Isolation von einem Mantel aus Polyamid umgeben ist. Auf dem Zentralstück 3 sind unter einem Winkel von 120° elastische Arme 6 befestigt. Die freien Enden der elastischen Arme 6 sind mit Stützrollen 7 versehen, die auf der Beschichtung 2 entlang rollen. Die elastischen Arme 6 sind zudem in Bewegungsrichtung zur Rohrachse hingeneigt. Die Bewegungsrichtung des Führungssternes ist durch einen Pfeil 8 angegeben. Die Bewegung wird ausgeführt, indem der Führungsstern mittels des Rohres 5 durch das Rohr 1 hindurchgeschoben wird. Das Rohr 5 ist in einer Kugelbuchse 9 gelagert, die eine Lineardurchführung ermöglicht. Die Kugelbuchse 9 selbst ist in einem Flansch 10 befestigt, der mit Hilfe von drei Zugankern 11 auf das Rohrende gedrückt wird. Das Gegenlager für die Zuganker 11 bilden drei kleine Klötze 12, die unter einem Winkel von 120° auf der Rohraußenseite angeheftet sind.In Fig.1 u. 2 shows a tube 1 which has a coating 2 on the inside which is to be removed. According to the invention, a self-centering guide star which is arranged in the interior of the tube 1 and which can be displaced in the interior of the tube 1 serves for this purpose. The guide star consists of a central piece 3, in which a spray nozzle 4 for liquid nitrogen is attached. The nitrogen is supplied through a tube 5, which is surrounded by a jacket made of polyamide for insulation. On the central piece 3 elastic arms 6 are attached at an angle of 120 °. The free ends of the elastic arms 6 are provided with support rollers 7 which roll along the coating 2. The elastic arms 6 are also inclined in the direction of movement to the tube axis. The direction of movement of the guide star is indicated by an arrow 8. The movement is carried out by pushing the guide star through the tube 1 by means of the tube 5. The tube 5 is mounted in a ball bushing 9, the one Linear feedthrough enabled. The ball bushing 9 itself is fastened in a flange 10 which is pressed onto the pipe end with the aid of three tie rods 11. The counter bearing for the tie rods 11 form three small blocks 12 which are attached to the outside of the tube at an angle of 120 °.

Bei Inbetriebnahme wird der Führungsstern langsam durch das Rohr in Richtung des Pfeiles 8 geschoben und fortschreitend die Beschichtung 2 mit flüssigem Stickstoff besprüht. Das sich entwickelnde Stickstoffgas entweicht durch das offene Rohrende. Sobald die Beschichtung 2 durchgehend versprödet ist, wird der Flansch 10 abgenommen, der Führungsstern entfernt und die Beschichtung durch mechanische Einwirkung entfernt. Hierzu genügen in der Regel leichte Hammerschläge auf die Außenseite des Rohres. Wenn die Beschichtung nicht in einem Rohr, sondern in einem langen zylindrischen Behälter entfernt werden soll,müssen im Flansch 10 öffnungen vorgesehen werden, durch welche der gasförmige Stickstoff entweichen kann.When starting up, the guide star is slowly pushed through the tube in the direction of arrow 8 and the coating 2 is progressively sprayed with liquid nitrogen. The developing nitrogen gas escapes through the open pipe end. As soon as the coating 2 is permanently brittle, the flange 10 is removed, the guide star is removed and the coating is removed by mechanical action. As a rule, light hammer blows on the outside of the tube are sufficient. If the coating is not to be removed in a tube, but in a long cylindrical container, 10 openings must be provided in the flange through which the gaseous nitrogen can escape.

Für die einwandfreie Funktion der erfindungsgemäßen Vorrichtung ist es wichtig, daß die Arme 6 aus einem Material bestehen, welches auch im Tieftemperaturbereich noch elastische Eigenschaften aufweist. Vorteilhafterweise werden die Arme aus einem Kunststoff mit entsprechenden Eigenschaften als Blattfedern ausgebildet. Diese Kostruktion ist besonders einfach und robust. Es ist vorteilhaft, wenn die Arme 6 leicht auswechselbar auf dem Zentralstück 3 befestigt sind. Es können dann auf dem Zentralstück 3 jeweils unterschiedlich lange Arme 6 befestigt werden, so daß eine Anpassung an verschiedene Rohrdurchmesser möglich ist. Desgleichen ist es zweckmäßig, den Flansch 10 so auszubilden, daß er an verschiedenen Rohrdurchmessern angesetzt werden kann. Hierzu können die Bohrungen zur Aufnahme der Zuganker 6 im Flansch unterschiedliche Entfernungen vom Mittelpunkt des Flansches haben. Bei Rohren mit großem Durchmesser werden die weiter innenliegenden Bohrungen zugeschraubt, damit durch sie kein Gas entweichen kann.For the proper functioning of the device according to the invention, it is important that the arms 6 consist of a material which also has elastic properties even in the low temperature range. The arms are advantageously formed from a plastic with corresponding properties as leaf springs. This structure is particularly simple and robust. It is advantageous if the arms 6 are attached to the central piece 3 in an easily replaceable manner. Arms 6 of different lengths can then be fastened on the central piece 3, so that an adaptation to different pipe diameters is possible. Likewise, it is expedient to design the flange 10 so that it can be attached to different pipe diameters. For this purpose, the holes for Recording the tie rod 6 in the flange have different distances from the center of the flange. In the case of pipes with a large diameter, the holes located further inside are screwed in so that no gas can escape through them.

Es sind selbstverständlich auch andere Konstruktionen für die elastischen Arme 6 möglich. Sie können auch senkrecht auf dem Zentralstück 3 angeordnet sein und müssen dann senkrecht zur Rohrachse elastisch sein. Dies ist z.B. mit Hilfe von Schraubenfedern möglich, doch setzt die bei tiefen Temperaturen beginnende Materialversprödung derartigen Konstruktionen Grenzen.Of course, other constructions for the elastic arms 6 are also possible. They can also be arranged vertically on the central piece 3 and must then be elastic perpendicular to the pipe axis. This is e.g. possible with the help of coil springs, but the material embrittlement that begins at low temperatures sets such constructions limits.

Fig.3 zeigt eine Abwandlung der erfindungsgemäßen Vorrichtung, die auch in gekrümmten Rohren verwendet werden kann. Für gleiche Teile wurden die gleichen Bezugsnummern verwendet. Das Zentralstück des Führungssternes ist hierbei als Rohrabschnitt 13 ausgebildet, an dessen Enden jeweils drei elastische Arme 6 unter 120° angeordnet sind. Die Arme 6 sind nach beiden Seiten zur Rohrachse hin geneigt. Die Stickstoffzufuhr erfolgt durch einen elastischen Isolierschlauch 14, der durch eine Bohrung im Flansch 10 geführt wird. Mittels einer Kette 15 wird der Führungsstern durch das Rohr 1 gezogen. Diese abgewandelte Vorrichtung kann auch durch ein gekrümmtes Rohr bewegt werden, da sich der Isolierschlauch 14 und die Kette 15 der Rohrkrümmung anpassen. Wegen der Elastizität der Arme 6 können hierbei sogar verhältnismäßig scharfe Krümmungen durchfahren werden.3 shows a modification of the device according to the invention, which can also be used in curved pipes. The same reference numbers have been used for the same parts. The central piece of the guide star is designed as a tube section 13, at the ends of which three elastic arms 6 are each arranged at 120 °. The arms 6 are inclined towards the tube axis on both sides. The nitrogen is supplied through an elastic insulating tube 14, which is guided through a bore in the flange 10. The guide star is pulled through the tube 1 by means of a chain 15. This modified device can also be moved through a curved tube, since the insulating tube 14 and the chain 15 adapt to the tube curvature. Because of the elasticity of the arms 6, even relatively sharp curvatures can be traversed.

Claims (5)

1. Vorrichtung zum Aufbringen eines tiefsiedenden verflüssigten Gases auf Beschichtungen (2) in Rohren (1), um die Beschichtungen zu verspröden und durch nachfolgende mechanische Einwirkung zu entfernen, gekennzeichnet durch einen im Rohr längsverschiebbaren Führungsstern, welcher aus einem Zentralstück (3; 13) für die Aufnahme einer Sprühdüse (4) für das tiefsiedende verflüssigte Gas besteht, an dem elastische Arme (6) mit einem Ende befestigt sind, während das jeweils andere Ende der elastischen Arme auf der Beschichtung des Rohres verschiebbar ist.1. Apparatus for applying a low-boiling liquefied gas to coatings (2) in pipes (1) in order to embrittle the coatings and to remove them by subsequent mechanical action, characterized by a guide star which can be moved longitudinally in the pipe and which consists of a central piece (3; 13) for receiving a spray nozzle (4) for the low-boiling liquefied gas, to which elastic arms (6) are attached at one end, while the other end of the elastic arms is displaceable on the coating of the tube. 2. Vorrichtung nach Anspruch 1, gekennzeichnet durch drei unter einem Winkel von 120° angeordnete Arme.2. Device according to claim 1, characterized by three arms arranged at an angle of 120 °. 3. Vorrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die Arme in Bewegungsrichtung zur Achse des Rohres geneigt angeordnet sind.3. Apparatus according to claim 1 or 2, characterized in that the arms are arranged inclined in the direction of movement to the axis of the tube. 4. Vorrichtung nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daB die auf der Beschichtung des Rohres verschiebbaren Enden der Arme mit Stützrollen (7) versehen sind.4. Device according to one of claims 1 to 3, characterized in that the ends of the arms which can be moved on the coating of the tube are provided with support rollers (7). 5. Vorrichtung nach Anspruch 3, dadurch gekennzeichnet, daß die Arme als Blattfedern ausgebildet sind und aus auch im Tieftemperaturbereich noch elastische Eigenschaften aufweisendem Kunststoff bestehen.5. The device according to claim 3, characterized in that the arms are designed as leaf springs and consist of plastic also having elastic properties even in the low temperature range.
EP85110197A 1984-09-07 1985-08-14 Apparatus for applying a low boiling liquefied gas to the coatings in pipes Withdrawn EP0173896A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19843432869 DE3432869A1 (en) 1984-09-07 1984-09-07 DEVICE FOR APPLYING A LOW-BOILED LIQUID GAS TO COATINGS IN PIPES
DE3432869 1984-09-07

Publications (1)

Publication Number Publication Date
EP0173896A1 true EP0173896A1 (en) 1986-03-12

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Family Applications (1)

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EP85110197A Withdrawn EP0173896A1 (en) 1984-09-07 1985-08-14 Apparatus for applying a low boiling liquefied gas to the coatings in pipes

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EP (1) EP0173896A1 (en)
DE (1) DE3432869A1 (en)
ZA (1) ZA856835B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4028434A1 (en) * 1990-09-07 1992-03-12 Georg Michael Prof Dr In Daerr Polluted structure repair method - renders expansion-joint material hard and brittle by sudden freezing before removal
DE19807635A1 (en) * 1998-02-23 1999-08-26 Air Liquide Gmbh Procedure for removing bituminous and other adhering layers of impurities from wall surfaces
CN104801437A (en) * 2015-05-13 2015-07-29 李梦 Inner wall spraying device of round pipeline

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2859728A (en) * 1956-08-29 1958-11-11 James D Hobdy Spray nozzle
DE1248390B (en) * 1959-04-22 1967-08-24 Alberto J Reinhart Device for de-crusting pipelines
DE1750782A1 (en) * 1967-06-28 1971-03-11 Arx Paul Von Device with the help of which the inner wall of a pipe can be cleaned and / or given a protective coating
US4164325A (en) * 1977-11-21 1979-08-14 Watson John D High-pressure-rotary-nozzle apparatus
DE2906496A1 (en) * 1979-02-20 1980-08-28 Linde Ag Removing bonded plastics sheets from panel surfaces - by supercooling panels with liquid nitrogen to destroy adhesive properties of bonding agent
US4475260A (en) * 1983-01-31 1984-10-09 Beck Richard D Pipeline servicing tool

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2859728A (en) * 1956-08-29 1958-11-11 James D Hobdy Spray nozzle
DE1248390B (en) * 1959-04-22 1967-08-24 Alberto J Reinhart Device for de-crusting pipelines
DE1750782A1 (en) * 1967-06-28 1971-03-11 Arx Paul Von Device with the help of which the inner wall of a pipe can be cleaned and / or given a protective coating
US4164325A (en) * 1977-11-21 1979-08-14 Watson John D High-pressure-rotary-nozzle apparatus
DE2906496A1 (en) * 1979-02-20 1980-08-28 Linde Ag Removing bonded plastics sheets from panel surfaces - by supercooling panels with liquid nitrogen to destroy adhesive properties of bonding agent
US4475260A (en) * 1983-01-31 1984-10-09 Beck Richard D Pipeline servicing tool

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, unexamined applications, Sektion M, Band 3, Nr. 97 (M-69), 17. August 1979 THE PATENT OFFICE JAPANESE GOVERNMENT Seite 153 M 69 * JP - A - 54-73 472 * *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4028434A1 (en) * 1990-09-07 1992-03-12 Georg Michael Prof Dr In Daerr Polluted structure repair method - renders expansion-joint material hard and brittle by sudden freezing before removal
DE19807635A1 (en) * 1998-02-23 1999-08-26 Air Liquide Gmbh Procedure for removing bituminous and other adhering layers of impurities from wall surfaces
DE19807635B4 (en) * 1998-02-23 2015-12-17 Air Liquide Gmbh Dosing weigher with means for removing bituminous and similar contaminant layers from the surface of a wall
CN104801437A (en) * 2015-05-13 2015-07-29 李梦 Inner wall spraying device of round pipeline

Also Published As

Publication number Publication date
DE3432869A1 (en) 1986-03-20
ZA856835B (en) 1986-04-30

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