EP1369182B1 - Painting installation - Google Patents

Abstract

Arrangement for painting objects comprises a paint line (8) with a circulation pump (16) connecting a paint reservoir/circulation container (10) to a working position (2) and having a feed (20) leading to the working position and a return (22) leading from the working position to the paint reservoir/circulation container. A device (18) producing a pressure difference is provided between the feed and return. Several removal points (4, 6) are provided via tap lines between the feed and return at the working position so that the tap lines preferably contain paint with no dead space even during longer shutdown periods. The paint line has a constant cross-section at least in the section provided with the removal points. The removal points each have a pressure-regulating device for individually adjusting the pressure difference bleeding off via the removal points so that a desired flow cross-section through the tap lines is achieved.

Description

The invention relates to a device for painting objects, such as motor vehicle bodies, with a ring-guided, a circulation pump having color line which connects a Farbvorrats- or -zirkulationsbehälter with a job, usually a paint booth, and leading to the job leading and one of the workstation for Farbvorrats- or -zirkulationsbehälter recirculating return, wherein between the flow and return a device for producing a pressure difference is provided and wherein several sampling points are provided via stubs between flow and return at the work, so that the stubs preferably largely dead space also during prolonged breaks in color flow.

Such a painting device is known for example from DE-A-101 17 917.

Furthermore, from US-A-3,023,968 a similar painting device is known, wherein the flow is connected only via the sampling points, but not via a separate device for producing a pressure difference, with the return to a Farbvorrats- or -zirkulationsbehälter. At the respective removal points, a pressure control device in the form of a flow regulator with a downstream of the respective removal point throttle is known. The like discloses WO-A-95/33574.

A distinction is usually made between paint systems for water-based paints or lacquers and those for solvent-based paints or lacquers. Waterborne basecoats behave structurally viscous or tixothropic, which means that they become thinner, ie less viscous, as the flow speed increases, or become viscous or highly viscous at low flow rate or when the lacquer "stands" within the line, as a result of which segregation, that is to say a decrease in flow Pigment ingredients or the like, is reliably prevented. This makes it possible to provide branching or stub lines in water-based paints to the tapping points, where the lacquer can "stand" for a longer period of time without causing problems with demulsification of the lacquer when restarting the system or a single tapping point.

Solvent paints, on the other hand, behave physically like water. If they "stand" in a pipe, there are unwanted segregation phenomena, which must be avoided at all costs. Therefore, it is endeavored to always circulate solvent paints or inks in a line system and to provide a possible dead space-free routing within a ring-guided management system.

Lackiereinrichtungen for solvent-based coatings or dyeing have become known under the name "Tichelmann systems", which is understood to mean a ring-shaped color line system with multiple tapping points, in which the line sections, including the branch or branch lines, to the tapping points down to immediately Always be circulated in front of a spray gun or a mechanical extraction point. However, it proves to be complicated to achieve in such a generic system at all sampling points to meet the requirements of the paint or color fair flow rate. Known devices are designed such that supply-side line sections are formed with a smaller and return-side line sections with a larger inner line diameter. Likewise, further downstream pipe sections have a larger inner pipe diameter than upstream pipe sections. Through these measures, the pressure dropping along a flow path due to the flow resistance should be taken into account and achieved so that the same pressure difference drops as far as possible at a respective removal point, so that a flow velocity corresponding to the requirements is ensured in the circulation mode, but also in the painting operation. As already mentioned, however, the implementation in practice, especially in systems with multiple outlets designed as very problematic. The usability of standardized components is difficult, since depending on the length of the cable and the arrangement of the sampling points certain line internal diameter must be used. Also, the vote at the individual sampling points and their branch or branch lines is difficult because undefined flow rates at the sampling points already result as a result of different hose lengths, for example, in manual sampling points. Also, the decommissioning of a sampling point can lead to changed conditions at the other sampling points.

On this basis, the present invention is the Object on to improve a device of the type mentioned above so that the difficulties described above do not occur, in particular the production, adjustment and tuning of the system and the operation of the system is simplified.

This object is achieved by a painting device with the features of claim 1.

As a departure from the known Tichelmann system, it is proposed with the invention to use a ring-shaped color line with a constant internal line cross-section, at least in the region of the removal points, ie usually around a paint booth, which then has the advantage of being piggable, Thus, by passing through an at least limited yielding displacement (pig) can be cleaned. Nevertheless, so despite constant line cross-section over preferably the entire color line to ensure a sufficient flow velocities in the circulation at the sampling points, there is a pressure control device between flow and return provided with the falling over the sampling point pressure difference can then be set individually. This pressure difference, in the area of a sampling point over that of the flow leading branch or branch line drops down to the re-opening in the return, namely responsible for the flow through the branch or branch line in the circulation mode or causal. On the line inner cross-section can then be closed by the flow rate, which can be easily determined by a removal in a measuring vessel, on the flow rate. Usually, flow rates of 0.1 to 0.3 m / s for water-based paints and 0.3 to 0.7 m / s for solvent-based paints prove to be expedient. The invention thus proposes to set the desired pressure difference in the region of the removal point, regardless of the pressure setting in the region of a respective removal point at the flow and at the return pressure, provided that the pressure difference is only large enough.

The invention proves to be advantageous in that it is possible to resort to standardized components during the production of the system or the annularly guided ink duct. Even the previous planning is simplified, since no changing cable cross sections have to be considered. Upon completion of the system, a certain operating pressure, for example 20 bar, could be preset on the supply side. About the device for producing a pressure difference between flow and return then a very low return pressure can be specified on the return side. By individually adjusting the respective pressure control device in the region of the sampling points, the pressure dropping there can now be adjusted individually at each sampling point. This pressure then preferably remains constant over time. He can, however, In particular, if the supply pressure changes, for example because more extraction point has been added or individual removal points have been removed, it can easily be readjusted.

It has proven to be advantageous if the device for producing a pressure difference between flow and return is provided in a branching off from the paint line and again leading back to this line section. In this case, namely during operation breaks to clean the line system a continuously piggable line route available; Flow and return can therefore be cleaned together by introducing or removing a displacer (pig). During operation of the system, the color guide via the mentioned branching and returning to the color line line section, in which said device for manufacturing and maintaining, so a pressure control device or a throttle device, is provided.

The mentioned line section is preferably attached by means of a piggable 3/2-way branching device to the color line, wherein the branching device is preferably formed by a ball valve.

It has proved to be advantageous if at a manual tapping point with a hose length of 4 to 8 m each in the flow or return, which then can form the mentioned branch or branch lines, or attached to these branch or branch lines, a pressure difference from 4 to 8 bar, in particular from 5 to 7 bar, is adjustable. At a mechanical sampling point, pressure differences of 6 to 10 bar prove in particular from 8 to 10 bar, as advantageous and expedient.

The pressure control device according to the invention comprises a return flow regulator, which is arranged with respect to the removal point downstream or return side. Such a return regulator then keeps the pressure on its flow side, ie on the side of the extraction point, at a defined value relative to the return side.

Furthermore, it proves to be advantageous that with respect to the removal point upstream of a pressure measuring device, so for example a manometer, is provided in the associated branch or branch line. A user is then always informed about the flow pressure at a respective extraction point and can make any changes or adjustments to new operating conditions that may be required via the pressure control device, without further measurements of the volume flow having to be made.

Furthermore, it proves to be particularly advantageous if in the color line on the supply side and return side of the work and from the sampling points a lock device (pig station) for introducing and discharging a line internal diameter correspondingly formed displacement (pig) is provided for cleaning the paint line.

Figur 1

eine bevorzugte Ausführungsform einer erfindungsgemäßen Lackiereinrichtung, und

Figur 2

eine Detaildarstellung im Bereich einer Entnahmestelle.

Further features, details and advantages of the invention will become apparent from the appended claims and from the drawings and the following description of a preferred embodiment of the invention. In the drawing shows:

FIG. 1

a preferred embodiment of a coating device according to the invention, and

FIG. 2

a detailed representation in the area of a sampling point.

1 shows a painting device according to the invention, which has an indicated paint booth 2, in which a plurality of removal points are provided, namely manually operated hand-off points 4 as well as associated with a painting machine so-called automated tapping points 6. The paint booth 2 and the removal points 4, 6 are about an annularly guided paint line 8 connected to a circulation container 10 for paint or paint. The circulation container 10 is located in a separate from the spray booth 2 indicated color mixing space 12. In this color mixing chamber 12 is also a paint or the color containing delivery container 14, from the color passes through a Farbzuführleitung in the circulation tank 10 and can be nachgefördert if necessary , Furthermore, a circulation pump 16 is provided in the ring-shaped color line 8, which color from the circulation tank 10 to the paint booth 2 at the respective removal points 4, 6 passes. The line section from the circulation tank 10 to a device to be described later 18 for producing a pressure difference is used as a lead 20 of the paint line. 8 designated. From the device 18 from the color line 8 leads back to the respective removal points 4, 6 over back to the circulation tank 10. This line section is called return 22.

A respective extraction point 4, 6 is connected to the flow 20 and to the return 22, so it is arranged between flow and return. For this purpose, as shown in Figure 2, from the supply line 20, a spur line 24 to the immediate removal point, for example, a hand extraction point with a spray gun out. Furthermore, another branch line 26 leads from the immediate removal point to return 22. If between 22 flow and return 22 a sufficient pressure difference in the circulation mode or in the paint operation is maintained, color is from the flow 20 via the line 24 to the extraction point and on the Sting line 26 back into the return 22 pass. The stub lines 24, 26 and optionally subsequent thereto hose lines 28, 30 preferably lead substantially dead space up to an indicated valve means 32 of the sampling point, so that at least almost the entire color can be circulated in the circulation, so that at any point paint or paint in one Lead "stands" and leads to unwanted demixing phenomena.

In order to ensure a desired flow rate, for example in solvent paints between 0.3 and 0.7 m / s through the lines 24 to 30, a pressure control device 32 is provided in the form of a return pressure regulator 34 between the flow 20 and return 22 in the stub 26 whose input side 36 of the return pressure regulator 34 is at a time constant, adjustable pressure can be maintained. If, for example, the flow 20 in the region of the connection of the spur line 24 has a pressure of 20 bar within the paint line 8 and the return 22 is kept substantially unpressurized, it would be conceivable to regulate the return pressure regulator 34 to 12 bar, which then means that between the input side 36 of the return pressure regulator 34 and the flow 20 a pressure difference of 8 bar drops. Due to this pressure difference can then be ensured through the lines 24 to 30, taking into account the hose or line length and the line cross-section, a desired flow rate of the paint or varnish, so that no settling phenomena occur. In the stub line 24 immediately at the end of the branch from the flow 20, a pressure measuring device 38 is provided in the form of a manometer. In this way, a change in the form at this point can be easily realized and readjusted by the pressure control device 32 in the form of the return pressure regulator 34 accordingly. This also proves to be advantageous, for example, if additional sampling points are added or some sampling points are blocked, or if the supply pressure is changed for some reason.

In a respective pressure control device 32 can also take into account the specific requirements of the sampling point, it is usually at manual tapping points 4, a lower pressure difference than at machine tapping points, which cooperate with automatic lacquering inside the spray booth 2 set.

The device 18 for producing a pressure difference between flow 20 and return 22 of the color line 8 is provided in a branching off from the color line 8 and again leading back to this line section 40. At the respective branch point or junction, a piggable 3/2 way branching device 42 in the form of a ball valve 44 is provided for this purpose. In painting or circulation operation, the branching device 42 is set so that the entire circulation is passed through the line section 40 and thus through the device 18 for producing the pressure difference. If a color change is carried out at regular intervals in the series painting operation and the line is cleaned for this purpose, the branching device 42 is switched such that now the entire flow communication takes place via the relatively short line section 46 between the branching devices 42 and the line section 40 is therefore no longer traversed. This opens up the possibility, with suitable design of the branching device 42 and the short line section 46, to clean the entire color line in one pass by passing a displacement body (pig) through it. For this purpose, infiltration or discharge devices 48 and 50, so-called pig stations, are provided in flow and return within the color mixing chamber 12. But they could also be arranged outside the color mixing room.

Claims (8)

1. A device for painting objects, having a circular paint supply line (8) having a circulation pump (16), said paint supply line connecting a paint-supply or circulation container (10) to a work location (2), and having an outflow line (20) leading to the work location (2) and a return line (22) leading from the work location (2) to the paint-supply or circulation container (10), whereby a device (18) for generating a pressure differential is provided between the outflow line and return line and whereby at the work location (2) a plurality of application points (4, 6) are provided via tie lines (24, 26) between the outflow line (20) and the return line (22), so that the tie lines (24, 26) advantageously permit paint to flow through them even during longer operational pauses as much as possible without wake space, wherein the paint supply line (8) has a constant line cross-section at least in the line segment in which the plurality of application points (4, 6) are provided, and is therefore piggable, and each application point (4,6) has a pressure control device (32) in the form of a return control (34), which is arranged downstream of the application point (4, 6) or on the return side in the tie line (26), and using which the pressure differential dropping off across the application point (4, 6) can be individually adjusted, so that a desired flow velocity can be realized through the tie lines (24, 26).
2. The device as recited in Claim 1, wherein the device (18) for generating a pressure differential between the outflow line (20) and the return line (22) is provided in a line segment (40) that branches off from, and then returns to, the paint supply line (8).
3. The device as recited in Claim 2, wherein the line segment (40) is attached to the paint supply line (8) by a piggable 3/2-way branching device (42).
4. The device as recited in Claim 3, wherein the piggable 3/2-way branching device (42) is formed by a ball valve (44).
5. The device as recited in any of the preceding claims, wherein at a manual application point (4) a pressure differential can be set by the pressure control device (32) at 4-8 bar, in particular 5-7 bar.
6. The device as recited in any of the preceding claims, wherein at a machine-driven application point (6) a pressure differential can be set by the pressure control device (32) at 6-10 bar, in particular 8-10 bar.
7. The device as recited in any of the preceding claims, wherein a pressure measuring device (38) is provided in the appropriate tie line (24) on the outflow-line side from the application point.
8. The device as recited in any of the preceding claims, wherein, in order to clean the paint supply line (8), on the outflow-line side and on the return-line side from the work location and from the application points, a sluicing device (48, 50) is provided in the paint supply line (8) for sending a displacement member, which is configured in accordance with the line interior diameter, through the line.

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