Method for removing paint

Description

[0001] This invention relates to a method for removing old paint layer or layers from a surface by means of a suction nozzle which is connected by a hose to a vacuum source wherein a paint dissolving agent is supplied to the paint layer or layers and is allowed to act for a period which is sufficiently long to dissolve the paint layer or layers. A method of this kind is known from US-A-932 738.

[0002] Removing paint has always been combined with great difficulties and in particular removing organic paints such as oilpaints, plastic paints etc. The old linseed oil paint was removed only when the total paint layer was too thick. Scraper and blowlamp were effective means, but needed hard work, and were not quite riskless. Also lye was used on certain occasions in order to dissolve the paint layer which was then rinsed with water. Establishing the plastic paints on the market meant that the difficulties to a great degree increased. Different plastics were used as binding agents and plastic paints were used for painting surfaces which were not suited for that kind of paint. A well known example is "tight" plastic paints on plaster.

[0003] The methods which up to now have been most common are blasting, high pressure cleaning of different kinds and use of paint removing agents which are rinsed together with the paint, often by means of a liquid under high pressure. For obvious reasons no one of these methods can be used indoors without taking very extensive protective measure. When using all said methods outdoors, they have proved to cause larger or smaller damages on the surface. In particular, this is the case with plastic painted plaster.

[0004] The three known methods leave several things to be desired with respect to the environment. Both for the person working with the method and for the environment in general terms. It is necessary to take extensive protective measure in order not to spread dust, drops of water or chemicals around the object in question.

[0005] Further in a great part of our public environment there is a particular need for a flexible and cheap method for removing paint. The public environment is exposed to an extensive scrawling activity where spray-paint, spirit-pencils etc. are the most common tools for scrawling. Today there is no flexible and cheap paint removing method.

[0006] In the patent literature removal of paint by a chemical - mechanical method has been described in US patent 932. 738. According to the method a paint removal agent applied on the painted surface after which a nozzle is used to remove the dissolved paint. The nozzle is, via a hose, connected to a vacuum source. In such a method no rinsing agent is positively supplied to the nozzle. The method has however not been used in practice during the long time which has elapsed since the patent was sealed. Probably this depends on that the mixture of paint and liquid which is to be transported away from the surface is very difficult to handle and not without further measures follows the air stream.

[0007] The purpose of this invention is to achieve a method for removing paint which has not the drawbacks which the known methods have. The purpose has been achieved by means of a method in which a paint dissolving agent is supplied on a paint layer on a surface and is allowed to act a period until the layer has been dissolved. The method is characterized in that a rinsing agent either being a liquid or warm air, is supplied to the dissolved paint by means of the nozzle, the mixture of paint and rinsing agent being immediately sucked away after the supply of the rinsing agent through the nozzle and through the hose into a collecting container. It has proved to be advantageous to combine the chemical treatment with a mechanical treatment of the surface since that supports the fragmentation and loosening of the paint from the surface. The mechanical treatment can for instance be made by scraping means, brushes or the like which are applied on the nozzle which is used for sucking up the mixture. Supply of the rinsing agent should, when removing certain types of paint, preferably be directed to the place of the nozzle where the paint is collected before it is sucked away. The choice of rinsing agent depends on the type of paint. Plastic paint usually demands chemical agents of different types and in some cases also warm air could be used whereas water can be used for alcalic paint such as oil paint. The temperature of the water should in that case be more than 40°C. An after treatment agent can be applied to the surface at the same time as the dissolved paint layer is sucked away. Such an after treatment agent is used to remove remainders of the paint solving agent and stabilize the surface after removing the paint so that a new paint layer, can be applied on the surface without being damaged by any remaining paint dissolving agent.

[0008] The rinsing water is as a rule applied at a comparatively low pressure which is choosen with respect to the character of the surface i.e. so that damages do not arise on the surface and so that not to large water quantities are pressed into any opening in the surface.

[0009] The dissolved paint is transported to a separation unit in which the paint dissolving agent together with the paint is separated from the water. Then the paint dissolving agent is separated and reactivated in an activator unit so that it can again be used for dissolving paint layers.

[0010] This invention has the advantage that the bed, that is the surface on which the paint is supplied, is spared. Also sensitive beds as for instance bad plaster can simply be cleaned without damages. Further the method is very rapid and gives a bed which is dry, stabilized and which can immediately be used for repainting. By the invention also maximum cleanness and stability is achieved. It should be pointed out that also the outer porous structure of the surface by this method can be effectively cleaned.

[0011] The method is very suitable for removing paint indoors. Scrawling is easily removed and also fire classified paint when repainting corridors, stair- wells and other evacuation rooms. (The fire classification presupposes a certain maximum paint layer). The method makes a completely controlled and environment friendly use possible. It is further possible to reuse a reactivated paint removing agent vehicle makes the method economically competitive.

[0012] The invention will be described by means of an example with reference to the accompanying figure which schematically shows a complete plan for sucking away paint, applying an after treatment agent and transportation and separation of the paint dissolved.

[0013] In the figure 10 is a surface on which a paint layer 11 is applied. A paint dissolving agent is sprayed on the paint layer 11 and is allowed to act for some time. Then a nozzle 12 is moved on the surface, the nozzle being provided with a fixed or movable brush for mechanical treatment of the surface. The nozzle 12 is, by means of a hose 13, connected to a container 14 which in turn is connected to a vacuum source 15. The nozzle is also, by means of a hose 16, connected to a rinsing agent container 17 from which a rinsing agent is transported to the nozzle in the hose 16. The rinsing agent container can be provided with means, not shown, for heating the rinsing agent. If the rinsing agent is water it should have a temperature which is more than 40°C and preferably is 70 - 90°C. The rinsing agent is mixed with the dissolved paint remainder and the paint removal agent and is sucked away in the hose 13 to the container 14 in which it is collected. By choosing the quantity of rinsing agent supplied with respect to the capacity of the suction nozzle it is possible to remove the paint and liquid with a minimum of spill.

[0014] The mixture of the paint dissolving and rinsing agent in the container 14 can then be transported to a cleaning plant 18 from which the rinsing agent is separated and leaves via an outlet 19 and as an alternative is brought back to the rinsing agent container 17. The paint dissolving agent and the dissolved paint might also be transported to a separation unit 20 in which the paint removing agent is separated from the paint remainders, these remainders, leaving through an outlet 21 and later being taken care of in a separate plant for destruction of waste which is dangerous for the environment. The paint removing agent is transported to an activator unit 22 in which the removal agent is reactivated and leaves through an outlet 23 so that it can again be used for removing paint.

[0015] The rinsing container 17 is, via a hose, connected to a container 24 for an after treatment agent. This agent is supplied to the rinsing water during the last treatment of the wall in order to give the surface a pH-value which is about 7.

Claims

1. Method for removing old paint layer or layers from a surface by means of a suction nozzle which is connected by a hose to a vacuum source, wherein a paint dissolving agent is supplied to the paint layer or layers and is allowed to act for a period which is sufficiently long to dissolve the paint layer or layers, characterized in that a rinsing agent, either being a liquid or warm air, is supplied to the dissolved paint by means of the nozzle, the mixture of paint and rinsing agent being immediately sucked away after the supply of the rinsing agent through the nozzle and through the hose into a collecting container.

2. Method according to claim 1, characterized in that the rinsing agent is water.

3. Method according to claim 1 and 2, characterized in that the chemical removal of paint is combined with a mechanical treatment.

4. Method according to any of claims 1 - 3, characterized in that the temperature of the rinsing agent is more than 40°C when it is supplied.

5. Method according to any of the preceding claims, characterized in that an after treatment agent is supplied together with the rinsing agent in order to remove remainders of the paint dissolving agent and/or give the surface a pH-value of about 7.

6. Method according to any of the preceding claims, characterized in that the dissolved paint is then transported to a cleaning plant in which the paint dissolving agent and the paint is separated from the rinsing agent.

7. Method according to claim 6, characterized in that the paint dissolving agent is separated and reactivated in an activator unit for reuse.

8. Method according to claim 3, characterized in that the rinsing agent is supplied near the part where the dissolved paint is collected on the mechanical device which is used for the treatment.

Ansprüche

1. Verfahren zum Entfernen einer oder mehrerer alter Farbschichten von einer Oberfläche mit Hilfe einer über einen Schlauch mit einer Vakuumquelle verbundenen Saugdüse, wobei auf die Farbschicht oder Farbschichten ein Farblösungsmittel aufgebracht wird, das man über einen zur Auflösung der Farbschicht oder Farbschichten ausreichend langen Zeitraum einwirken läßt, dadurch gekennzeichnet, daß der gelösten Farbe ein als entweder Flüssigkeit oder Warmluft vorliegendes Spülmittel mit Hilfe der Düse zugeführt und das Gemisch aus Farbe und Spülmittel unmittelbar nach Zufuhr des Spülmittels durch die Düse und durch den Schlauch in einen Sammelbehälter abgesaugt wird.

2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß das Spülmittel Wasser ist.

3. Verfahren nach Anspruch 1 und 2, dadurch gekennzeichnet, daß die chemische Entfernung der Farbe mit einer mechanischen Behandlung kombiniert ist.

4. Verfahren nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß die Temperatur des Spülmittels zum Zeitpunkt seiner Zufuhr mehr als 40° C beträgt.

5. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß ein Nachbehandlungsmittel zusammen mit dem Spülmittel zugeführt wird, um Rückstande des Farblösungsmittels zu entfernen und/oder der Oberfläche einen pH-Wert von etwa 7 zu verleihen.

6. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die gelöste Farbe anschließend zu einer Reinigungsanlage transportiert wird, in der das Farblösungsmittel und die Farbe von dem Spülmittel getrennt werden.

7. Verfahren nach Anspruch 6, dadurch gekennzeichnet, daß das Farblösungsmittel getrennt und in einer Aktivierungseinheit zur Wiederverwendung reaktiviert wird.

8. Verfahren nach Anspruch 3, dadurch gekennzeichnet, daß das Spülmittel nahe dem Teil zugeführt wird, wo die gelöste Farbe an der mechanischen Vorrichtung gesammelt wird, die zu der Behandlung verwendet wird.

Revendications

1. Procédé d'enlèvement d'une ou plusieurs couches de vieille peinture d'une surface à l'aide d'une buse d'aspiration qui est connectée par une tuyauterie souple à une source de vide, dans lequel un agent de dissolution de peinture est transmis à la couche ou aux couches de peinture et peut agir pendant une certaine période suffisamment longue pour que la couche ou les couches de peinture soient dissoutes, caractérisé en ce qu'un agent de rinçage, sous forme d'un liquide ou d'air chaud, est transmis à la peinture dissoute par la buse, le mélange de peinture et d'agent de rinçage étant immédiatement aspiré après application de l'agent de rinçage, à l'aide de la buse et de la tuyauterie souple, dans un réservoir collecteur.

2. Procédé selon la revendication 1, caractérisé en ce que l'agent de rinçage est de l'eau.

3. Procédé selon les revendications 1 et 2, caractérisé en ce que l'enlèvement chimique de la peinture est combiné à un traitement mécanique.

4. Procédé selon l'une quelconque des revendications 1 à 3, caractérisé en ce que la température de l'agent de rinçage est supérieure à 40° C en cours d'application.

5. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce qu'un agent de post-traitement est appliqué avec l'agent de rinçage afin qu'il supprime les restes de l'agent de dissolution de la peinture et/ou donne à la surface une valeur de pH d'environ 7.

6. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que la peinture dissoute est transportée vers une installation de nettoyage dans laquelle l'agent de dissolution de peinture et la peinture sont séparés de l'agent de rinçage.

7. Procédé selon la revendication 6, caractérisé en ce que l'agent de dissolution de la peinture est séparé et réactivé dans un ensemble d'activation afin qu'il puisse être réutilisé.

8. Procédé selon la revendication 3, caractérisé en ce que l'agent de rinçage est appliqué près de la partie dans laquelle la peinture dissoute est collectée sur le dispositif mécanique qui est utilisé pour le traitement.

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