DE102014100328A1 - painter - Google Patents

Abstract

The present invention relates to a spray device for water vapor-assisted coating of substrates, the condensation largely or even completely prevented. For this purpose, a tempered water vapor supply line (10) is proposed, in which the temperature is controlled by means of a circulating tempering fluid.

Description

FIELD OF THE INVENTION

The present invention relates to a spray device for atomizing and spraying coating material by means of water vapor. In addition, the present invention relates to a corresponding method.

STATE OF THE ART

A number of coating methods are known from the prior art, in which a substrate is provided with a coating material or paint. Corresponding coating materials contain, in addition to macromolecular or macromolecule-forming film formers, pigments, fillers, additives and / or solvents or dispersants. Solvents here are to be understood as meaning all liquids or liquid mixtures which are capable of dissolving the film former or film formers, such as e.g. Alcohols or water. By dispersant is meant liquids that do not dissolve the film former but maintain a fine, microheterogeneous distribution, e.g. Hydrocarbons or water.

In order to apply the coating materials to a substrate, spraying or spraying processes are used in particular, since they permit the most uniform possible formation of lacquer. Water vapor-assisted spraying or spraying processes have proven to be particularly advantageous in which the coating material is finely atomized by steam in a spraying or spraying device and transported to the substrate.

However, in the steam-assisted spraying method there is a risk that the water vapor may condense on the way to the spray gun or in the spray gun, so that together with the coating material drops of condensation water get on the object to be coated and thus the quality of the coating is impaired.

To avoid condensation of the water vapor, the DE 10 2006 019 365 A1 For example, the use of superheated steam at a temperature of 200 ° C or more before. Even with the use of superheated steam, it can just come in the start-up phase of the system, when all steam-carrying parts are not yet at operating temperature, or after prolonged pauses, or with long steam lines to the formation of condensation water drops. The DE 10 2005 029 687 A1 on the other hand discloses a steam air dryer which is integrated into the spray nozzle, so that the condensation water is discharged from the spray device before mixing the water vapor with the coating material. With the use of a steam dryer, however, excessive condensation may result in not enough condensate being drained and thus escaping through the nozzle.

The DE 10 2005 029 688 A1 discloses a heated steam channel in a spray head, the heating being electrical. Such a heater is insufficient because it takes place only in a short area in the spray head and water droplets that may arise on the way from the steam generator to the spray head, neither avoids nor can eliminate. In addition, the control of the required heating temperature is difficult.

OBJECT OF THE INVENTION

Starting from the prior art, it is therefore an object of the present invention to provide a device for coating objects that makes it possible that condensation is largely or even completely avoided. In addition, the device should be simple and operable.

TECHNICAL SOLUTION

The object described above is achieved by a spraying device according to claim 1 and a method for spraying and spraying coating material or lacquer according to claim 10. Advantageous developments of the invention are the subject of the subordinate claims.

According to the invention, a spraying device includes a supply device for supplying water vapor from a steam generator to a spray head or a spray gun of the spray device for spraying coating material. The supply device comprises a steam line for conducting the superheated steam, wherein the steam line is temperature controlled. This can avoid that the temperature of the water vapor in the supply line from the steam generator to the spray gun does not cool to the saturation temperature of the water vapor and thereby condenses. Thus, the water vapor can be kept at a suitable temperature for long stretches and condensate formation can be effectively avoided even at long distances between the steam generator and the spray gun.

Advantageously, the supply device has a tempering device, which can temper the steam line over a length of at least 80%, in particular at least 90%, in particular at least 95%, of the length of the steam line. Thus, it can be ensured that the inner wall of the Steam line over the length of the steam line a suitable temperature, preferably a temperature of 100 ° C-220 ° C or more, and thus does not cool the water vapor in the steam line and condensed.

For this purpose, the spraying apparatus according to the invention has a tempering fluid channel surrounding the steam line, through which a temperature control means for controlling the temperature of the steam line can be guided. For a particularly effective and simple heating of the steam line is possible, especially if water vapor is used as the temperature control, which is also used as a sputtering agent and is guided in the steam line.

The Temperierfluidkanal may be arranged coaxially to the steam line, so that a uniform annular channel is formed around the steam line and allows a uniform temperature over the entire length of the steam line.

The tempering fluid advantageously has a temperature which is equal to or higher than the temperature of the water vapor inside the inner pipe body, in particular a temperature of 100 ° C -220 ° C or more.

If steam is used as tempering fluid from the steam generator for the provision of the atomizing agent, the expense for the production of the tempering fluid is low and the condensed water vapor can be easily returned to the steam generator and is reusable. In addition, the condensation is not harmful to the environment and may also be released to the environment.

In addition, the Temperierfluidkanal, which surrounds the steam line, an electric heating unit, for example, a resistance heater, which in addition to a thermal insulation of the Temperierfluidkanals ensures a sufficiently high temperature of the Temperierfluids in Temperierfluidkanal.

The steam line and the Temperierfluidkanal can be fixed to each other by means of spacers, so that the most uniform possible flow of the temperature control is ensured by the Temperierfluidkanal.

The steam line and the Temperierfluidkanal are advantageously formed flexible. They may consist of a flexible material and / or of mutually movable members which are sealed against each other.

The supply device may further include a steam dryer, with which the steam line and / or the Temperierfluidkanal may be connected to dry the water vapor before the introduction into the steam line and / or the Temperierfluidkanal. The connection with the steam dryer thus prevents condensed water from entering the steam line and being directed towards the spray gun, and too much condensed water forming in the tempering fluid channel.

The supply device according to the invention may also contain a pressure reducer, via which the steam line is connected in particular via the steam dryer with the steam generator. The pressure reducer can be adjusted so that water vapor at a pressure between 15 bar and 20 bar, in particular 18 bar, as produced by the steam generator is reduced to a pressure of 2 to 5 bar, as it is used for atomizing and spraying , This results in superheated steam which has the same temperature as the saturated steam which is introduced as tempering in the Temperierfluidkanal, this preferably not passed through the pressure reducer, but introduced at higher pressures in Temperierfluidkanal so that the boiling temperature of the water vapor in Temperierfluidkanal higher is as the water vapor in the steam line. This measure ensures that the superheated steam used for spraying never cools down to such an extent that condensation can form. Even during the start-up phase or after longer breaks it is ensured that the water vapor used for spraying can not cool down in the line.

For introducing steam into the Temperierfluidkanal the supply device may contain at least one connecting element, via which the water vapor from the steam generator or the steam dryer in the Temperierfluidkanal can be introduced. In order to prevent condensate from accumulating in the tempering fluid channel, the supply device may contain a condensate separator which is connected to the tempering fluid channel. Furthermore, a return line from the condensate to the steam generator may be provided to re-evaporate the condensate.

The Temperierfluidkanal may further comprise at least one insulation surrounding the Temperierfluidkanal from the outside, to prevent heat loss and thus to reduce energy consumption.

The present invention further relates to a method for sputtering and spraying of coating material, wherein water vapor, while it travels through a steam line, is tempered with the aid of a tempering fluid, which flows around the steam line. To carry out the method, a spray device according to the invention, as described in the preceding paragraphs, can be used.

The steam for atomizing the coating material is preferably tempered during its supply to the spray gun or nozzle device so that it does not substantially condensed. Preferably, the steam is maintained at temperatures of 100 ° C-220 ° C or more to prevent condensation.

Advantageously, water vapor can be used as the tempering fluid. This can be dispensed with an additional provision of a tempering. The present invention thus makes it possible to easily avoid the condensation of water vapor in steam-assisted spraying process without unduly increasing the effort. In particular, the use of steam as the heating means is an efficient temperature control. This method can also be applied within the fuel gun by the channel that leads the water vapor for atomization, by another channel that leads the tempering fluid is surrounded.

BRIEF DESCRIPTION OF THE FIGURES

Hereinafter, the device according to the invention for coating objects and the associated method will be explained with reference to drawings. The accompanying drawings show in a purely schematic manner in FIG

1 a coating device according to the invention with Wasserdampftemperierung; and in

2 a coating device according to the invention with combined temperature control.

EMBODIMENTS

Further advantages, characteristics and features of the present invention will become apparent from the following detailed description of the embodiments. However, the invention is not limited to these embodiments.

The 1 shows a spray device for coating objects, in particular substrates (not shown), can be performed with the steam-assisted painting. The spray device comprises a supply device 1 , a spray gun 2 with nozzle arrangement for generating a spray jet 20 , and a steam generator 3 , The supply device 1 includes a steam line 10 through which water vapor from the steam generator 3 to the spray gun 2 to be led. The steam line 10 is from an outer tempering fluid channel 11 surrounded, the steam pipe 10 coaxial in the tempering fluid channel 11 is recorded, so that an annular cross-section 110 of the tempering fluid channel 11 arises. On the outside of the Temperierfluidkanals 11 is insulating material 12 provided to prevent heat loss.

The steam line 10 is via a steam dryer 14 and a pressure reducer 13 , Which reduces the water vapor pressure of about 18 bar in the steam generator to about 2 to 5 bar, preferably 3 to 4 bar, with the steam generator 3 connected. The tempering fluid channel 11 is via an additional conduit 15 with the steam dryer 14 connected so that water vapor from the steam dryer 14 in the tempering fluid channel 11 can be introduced. To the tempering fluid channel 11 In addition, a condensate separator is discharged 16 formed, which with the Temperierfluidkanal 11 is connected and separated condensate via a connecting line between Kondensatabscheider 16 and steam generator 3 to the steam generator 3 returns.

As a heating medium in the Temperierfluidkanal 11 introduced water vapor (saturated water vapor) has a higher pressure but the same temperature as that through the steam line 10 Guided water vapor (superheated steam), so that in the tempering fluid channel due to heat loss condensate is formed, but this condensate is constantly replaced by new saturated steam. At the same time, however, the temperature maintenance in the tempering fluid channel prevents the water vapor in the water vapor line 10 cools down, so that no condensate can form here.

Regarding the steam line 10 and the tempering fluid channel 11 It should be noted that these are purely schematic and not in proportion to the spray gun 2 and the steam generator 3 are shown. In particular, it should be noted that it is the steam line 10 and the tempering fluid channel 11 to flexible hoses, especially a coaxial hose can act.

The 2 shows a further coating device, wherein the supply device 1' a combination of steam tempering, like them in 1 is shown, and an electric temperature is. In particular, between the Temperierfluidkanal 11 and the insulation 12 an electrical resistance heater 18 provided, which additionally cooling the water vapor in the Temperierfluidkanal 11 avoids and thus even better the uniform temperature of the steam line 10 allows.

In summary, the present application provides a spray device which in a simple yet effective manner prevents the condensation of water vapor in the supply line to a nozzle assembly and in the nozzle assembly and thus ensures a uniform and high quality coating of articles.

Although the present invention has been described in detail by the embodiments, it will be understood by those skilled in the art that the invention is not limited to these embodiments, but rather variations and modifications in particular by omission or other combination of individual features of the invention are possible, as long as the scope of the appended claims. The present disclosure includes all combinations of the features presented.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102006019365a1 [0005]
• DE 102005029687 A1 [0005]
• DE 102005029688 A1 [0006]

Claims (12)

Spray device for spraying and applying coating material on an object with a supply device ( 1 ) for supplying water vapor as a sputtering agent from a steam generator ( 3 ), wherein the supply device a steam line ( 10 ) for conducting steam, characterized in that the steam line in an outer, the steam line surrounding Temperierfluidkanal ( 11 ), wherein a tempering agent can be guided through the tempering fluid channel around the steam line. Spray device according to claim 1, characterized in that the steam line ( 10 ) over a length of at least 80%, in particular at least 90%, in particular at least 95%, of a length of the steam line from the Temperierfluidkanal ( 11 ) is surrounded. Spray device according to one of the preceding claims, characterized in that the tempering fluid channel ( 11 ) coaxial to the steam line ( 10 ) is arranged. Spray device according to one of the preceding claims, characterized in that the tempering fluid channel ( 11 ) an electric heating unit ( 18 ), in particular a resistance heater. Spray device according to one of the preceding claims, characterized in that the steam line ( 10 ) and the tempering fluid channel ( 11 ) are flexible. Spray device according to one of the preceding claims, characterized in that the steam line ( 10 ) and / or the tempering fluid channel ( 11 ) with a steam dryer ( 13 ) are connected, can be introduced via the water vapor from the steam generator in the steam line and / or the Temperierfluidkanal. Spray device according to one of the preceding claims, characterized in that the steam line via a pressure reducer ( 14 ) is connected to the steam generator and / or a steam dryer. Spray device according to one of the preceding claims, characterized in that the supply device is a connecting element ( 15 ) contains, via the water vapor from the steam generator in the Temperierfluidkanal can be introduced. Spray device according to one of the preceding claims, characterized in that the Temperierfluidkanal a Kondensatabscheider ( 16 ). Method for atomising and spraying coating material, in particular using a spraying device according to one of claims 1 to 9, wherein water vapor is used as atomizing agent while passing through a steam line ( 10 ), with the aid of a tempering fluid, which flows around the steam line is tempered. A method according to claim 10, characterized in that water vapor is used as the tempering fluid, in particular water vapor from the same steam generator ( 3 ), from which comes the water vapor, which is used as atomizer. A method according to claim 10 or 11, characterized in that the tempering fluid is under a higher pressure than the water vapor in the steam line ( 10 ), whereby there is superheated steam in the steam line.

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